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1

Relativity and Magnetism in Ni-Pd and Ni-Pt Alloys Abstract  

E-Print Network (OSTI)

We show that the differences in the magnetic properties of Ni-Pd and Ni-Pt alloys arise mainly due to relativity. In particular, we find that the local magnetic moment of Ni increases with the addition of Pd in Ni-Pd while it decreases with the addition of Pt in Ni-Pt, as found experimentally, only if relativity is present. Our analysis is based on the effects of relativity on (i) the spin-polarized densities of states of Ni, (ii) the splitting of majority and minority spin d-band centers of Ni, and (iii) the separation between s-d band centers of Pd and Pt in Ni-Pd and Ni-Pt alloys. 1

Prabhakar P. Singh

2002-01-01T23:59:59.000Z

2

Middle distillate hydrotreatment zeolite catalysts containing Pt/Pd or Ni  

E-Print Network (OSTI)

A study on middle distillate hydrotreatment zeolite catalysts containing Pt/Pd and/or Ni was performed. The effect of the addition of the corresponding CoMo, CoMoPd, CoMoPtPd and CoMoNi in PdNiPt-zeolite, Pt-zeolite, Ni-zeolite, and PdPt-zeolite was studied. The catalysts were characterized physically and chemically by methods and techniques such as Brunauer-Emmett-Teller (BET), Barret-Joyner-Hallenda (BJH), and neutron activation analysis. The structures of the Ni and Pt containing zeolite were studied by X-ray Photoelectron Spectroscopy (XPS). An experimental apparatus was constructed to investigate the activity of the experimental catalysts. The catalysts activity measured in terms of conversion of dibenzothiophene (DBT), substituted dibenzothiophenes (sDBT) and phenanthrene as well as molar-averaged conversion was evaluated in a continuous flow Robinson Mahoney reactor with stationary basket in the hydrodesulfurization and hydrogenation of heavy gas oil which contains sulphur refractory compounds such as 4- methyldibenzotiophene (4-MDBT) and 4,6- dimethyldibenzothiophene (4,6-DMDBT). DBT, 4-MDBT, 3-MDBT, 1-EDBT, 3-EDBT, 4,6-DMDBT, 3,6-DMDBT, 2,8- DMDBT and 4-methylnaphtho[2,1-b]thiophene were selected to calculate the molaraveraged conversion. The conversions of the sulfur containing compounds and phenanthrene were determined as a function of the operating variables: space time (W/Fo DBT), temperature, H2/HC mol ratio and pressure. The Conversions of DBT and 4,6-DMDBT into their reaction products such as Biphenyl (BPH), Cyclohexylbenzene (CHB), Bicyclohexyl (BCH) and 3,4-Dimethylbiyphenyl (3,4-DMBPH) were determined only as a function of space time in the interval of 4000-6000 kgcath/kmol. The results of this work showed that Pt-HY and PdPt-HY are good noble metals catalysts for the hydrodesulfurization of heavy gas oil. Moreover, this study showed that CoMoPd/Pt-HY and CoMoNi/PdPt-HY catalysts are good candidates for deep HDS and hydrogenation of heavy gas oil. It was found that the conversions of sulfur compounds were higher than the conversions provided by the conventional CoMo/Al2O3 catalyst. Also higher hydrogenation of phenanthrene was observed. Deactivation of the catalysts was not observed during the operation. Finally, the study not only contributed to define the technical bases for the preparation of the noble metal catalysts for hydrodesulfurization of heavy gas oil at pilot scale, but also provided technical information for developing the kinetic modeling of the hydrodesulfurization of heavy gas oil with the noble metal catalysts.

Marin-Rosas, Celia

2006-12-01T23:59:59.000Z

3

{sup 45}Sc Solid State NMR studies of the silicides ScTSi (T=Co, Ni, Cu, Ru, Rh, Pd, Ir, Pt)  

SciTech Connect

The silicides ScTSi (T=Fe, Co, Ni, Cu, Ru, Rh, Pd, Ir, Pt) were synthesized by arc-melting and characterized by X-ray powder diffraction. The structures of ScCoSi, ScRuSi, ScPdSi, and ScIrSi were refined from single crystal diffractometer data. These silicides crystallize with the TiNiSi type, space group Pnma. No systematic influences of the {sup 45}Sc isotropic magnetic shift and nuclear electric quadrupolar coupling parameters on various structural distortion parameters calculated from the crystal structure data can be detected. {sup 45}Sc MAS-NMR data suggest systematic trends in the local electronic structure probed by the scandium atoms: both the electric field gradients and the isotropic magnetic shifts relative to a 0.2 M aqueous Sc(NO{sub 3}){sub 3} solution decrease with increasing valence electron concentration and within each T group the isotropic magnetic shift decreases monotonically with increasing atomic number. The {sup 45}Sc nuclear electric quadrupolar coupling constants are generally well reproduced by quantum mechanical electric field gradient calculations using the WIEN2k code. Highlights: Black-Right-Pointing-Pointer Arc-melting synthesis of silicides ScTSi. Black-Right-Pointing-Pointer Single crystal X-ray data of ScCoSi, ScRuSi, ScPdSi, and ScIrSi. Black-Right-Pointing-Pointer {sup 45}Sc solid state NMR of silicides ScTSi.

Harmening, Thomas [Institut fuer Anorganische und Analytische Chemie and NRW Graduate School of Chemistry, Universitaet Muenster, Corrensstrasse 30, D-48149 Muenster (Germany); Eckert, Hellmut, E-mail: eckerth@uni-muenster.de [Institut fuer Physikalische Chemie, Universitaet Muenster, Corrensstrasse 30, D-48149 Muenster (Germany); Fehse, Constanze M. [Institut fuer Physikalische Chemie, Universitaet Muenster, Corrensstrasse 30, D-48149 Muenster (Germany); Sebastian, C. Peter, E-mail: sebastiancp@jncasr.ac.in [New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064 (India); Poettgen, Rainer, E-mail: pottgen@uni-muenster.de [Institut fuer Anorganische und Analytische Chemie and NRW Graduate School of Chemistry, Universitaet Muenster, Corrensstrasse 30, D-48149 Muenster (Germany)

2011-12-15T23:59:59.000Z

4

K[sub 10]In[sub 10]Z (Z = Ni, Pd, or Pt): Zintl phases containing isolated decaindium clusters centered by transition elements  

Science Conference Proceedings (OSTI)

The isostructural title compounds are obtained by high yield by slowly cooling the appropriate fused mixture in welded Ta. They occur in the orthorhombic space group Pnma, Z = 12, with a = 15.948(6), 16.043(6), 16.056(3) Angstroms, b = 32.565(6), 32.73(1) Angstroms, and c = 18.822(3), 18.895(5), 18.896(3) Angstroms for the Ni, Pd, and Pt derivatives, respectively. The structure of the Ni phase was refined by single crystal means (R, R[sub w] = 2.9, 3.3%) and shown to be constructed from the close-packed layers of Ni-centered In[sub 10] clusters that are separated by potassium ions both within and between the cluster layers. The compounds have large resistivities at room temperature by two-probe methods and are diamagnetic, with no moments on the transition metals. The geometry of the clusters can be derived from an ideal tetracapped trigonal prism (C[sub 3v]) of In centered by Z through axial compression along the 3-fold axis and opening of the capped triangular face so as to yield substantially equal Ni-In distances. The clusters are also related to Sb[sub 7][sup 3[minus

Sevov, S.C.; Corbett, J.D. (Iowa State Univ., Ames, IA (United States))

1993-10-06T23:59:59.000Z

5

The Role of Al on the Thermodynamics of Hydrogen Absorption/Desorption by Some Ternary Pd-M-Al Alloys where M=Rh, Ni, Pt, Cr, Ag.  

DOE Green Energy (OSTI)

The solution of hydrogen and hydride formation in FCC substitutional solid solution Pd0.9Rh0.1-xAlx alloys have been examined. In contrast to some other Pd ternary alloys, a linear relation does not obtain between the H capacity and x for the Pd0.9Rh0.1-xAlx alloys investigated here where the H capacity of the alloys is estimated from the H content of the steeply rising part of the isotherms in the hydride phase regions. A linear increase of the dilute phase H solubility with x for these Pd0.9Rh0.1-xAlx alloys does, however, obtain for these alloys. Although Pd-Rh binary alloys have broader plateaux than does Pd itself, small amounts of Al substituted into Pd0.85Rh0.15 or Pd0.80Rh0.20 alloys can reduce or eliminate the two phase regions, the plateaux; there is, however, not much effect on the dilute phase solubilities. For example, small amounts of Al substituted into the Pd0.85Rh0.15 or Pd0.80Rh0.20 alloys eliminate the plateaux. On the other hand, alloying Pd with Al to form binary alloys with Xal equals 0.015 or 0.030 does not eliminate the plateaux which are present in these binary alloys up to Xal equals 0.075 (298 K). Small amounts of Al substitution do not have such a dramatic effect on the plateau widths of the Pd0.90Ni0.10 and Pd0.80Ni0.20 alloys and similarly substitution of Al into Pd-Cr and Pd-Ag alloys does not introduce any anomalous effects into the isotherms.

Shanahan, K.L.

2002-04-10T23:59:59.000Z

6

Catalyst and process development for hydrogen preparation from future fuel cell feedstocks. Quarterly progress report, January 1, 1980-March 31, 1980. [Pt/Rh, Pd, Pt, Rh, Ni/Rh, Rh/Re, Ni  

DOE Green Energy (OSTI)

Catalysts are being screened to steam reform hydrocarbons in an autothermal reformer (STR). Twenty-one samples have been screened in a 1-in.-diam (ATR) reactor using No. 2 oil as the hydrocarbon feed. A series of platinum-rhodium catalysts were evaluated to study the effect of varying compositions. A sample containing 1.7% Pt/0.3% Rh was most active but the difference among the samples was within the range of test variability. Development of a more realistic test has been started. The effect of O/sub 2//C level on the gas composition leaving the catalytic partial oxidation section has been determined. The amount of unreacted oil increases as O/sub 2//C level decreases. The unreacted oil is more aromatic than the feedstock. The gas composition contains considerably more olefins as the O/sub 2//C level decreases. Post-run catalyst characterization indicates that the catalyst carrier does not deteriorate in the ATR test. A drastic decrease in CO chemisorption is noted on the Pt/Rh samples. This decline in CO chemisorption could either be due to metal sintering or to carbon deposition on the metal. Other analysis are required to determine which is causing the decline in CO chemisorption. Very low coke levels were found on Pt, Rh, and Pt/Rh samples. Addition of Rh to nickel reduces the coke level over that observed for nickel catalysts.

Yarrington, R M; Feins, I R; Hwang, H S

1980-04-01T23:59:59.000Z

7

Thermodynamic approach to glass-forming ability of water-quenched Pd-P-based and Pt{sub 60}Ni{sub 15}P{sub 25} bulk metallic glasses  

SciTech Connect

Despite its importance, a thermodynamic approach to determining the glass-forming ability (GFA) of bulk metallic glass (BMG) remains a goal to be achieved. We examined the GFA of water-quenched Pd-P-based and Pt{sub 60}Ni{sub 15}P{sub 25} BMG's in which their molten alloys were sufficiently treated with a dehydrated B{sub 2}O{sub 3} flux prior to and during quenching to room temperature. This allowed us to envisage the applicability of the classical steady-state homogeneous nucleation theory because the suppression of heterogeneous nucleation worked effectively. GFA was examined by comparing the critical cooling rate R{sub c}{sup h} for glass formation with the maximum diameter d{sub max} of glass. To calculate R{sub c}{sup h}, the homogeneous nucleation rate I{sub ss}(T), and the growth rate u{sub c}(T) were estimated as functions of the undercooling temperature of molten alloys. Then, the free energy difference {Delta}G{sub L-x}(T) between the liquid and crystalline phases, and the viscosity {eta}(T) of the liquid were experimentally determined while the surface energy {sigma}{sub sL}(T) at the liquid-nucleus interface was estimated by calculation. The d{sub max} of rod BMG's correlated strongly to R{sub c}{sup h} through the relation R{sub c}{sup h} {approx_equal}d{sub max}{sup -3}/10 mm{sup 3} Ks{sup -1}.

Haruyama, O.; Watanabe, T.; Yuki, K.; Horiuchi, M. [Faculty of Science and Technology, Tokyo University of Science, Noda 278-8510 (Japan); Kato, H. [Institute of Materials Research, Tohoku University, Sendai 980-8577 (Japan); Nishiyama, N. [RIMCOF Tohoku University Laboratory, The Materials Process Technology Center, Sendai 980-8577 (Japan)

2011-02-01T23:59:59.000Z

8

Preparation of PtNi Nanoparticles for the Electrocatalytic Oxidation of Methanol  

E-Print Network (OSTI)

Carbon supported PtNi nanoparticles were prepared by hydrazine reduction of Pt and Ni precursor salts under different conditions, namely by conventional heating (PtNi-1), by prolonged reaction at room temperature (PtNi-2) ...

Deivaraj, T.C.

9

Deactivation Mechanisms of Pt/Pd-based Diesel Oxidation Catalysts  

Science Conference Proceedings (OSTI)

Currently precious metal-based diesel oxidation catalysts (DOC) containing platinum (Pt) and palladium (Pd) are most commonly used for the oxidation of hydrocarbon and NO in diesel exhaust hydrocarbon oxidation. The present work has been carried out to investigate the deactivation mechanisms of the DOC from its real-world vehicle operation by coupling its catalytic activity measurements with surface characterization including x-ray diffraction, transmission electron microscopy, and x-ray photoelectron spectroscopy. A production Pt-Pd DOC was obtained after being aged on a vehicle driven for 135,000 miles in order to study its deactivation behavior. The performance of the vehicle-aged part was correlated with that of the simulated hydrothermal lab aged sample assuming that Pt-Pd sintering plays a major role in irreversible catalyst deactivation. In addition to the hydrothermal sintering, the deterioration of hydrocarbon and NO oxidation performance was caused by surface poisoning. The role of the various aging factors in determining long-term performance in mobile applications will be discussed.

Wiebenga, Michelle H.; Kim, Chang H.; Schmieg, Steven J.; Oh, Se H.; Brown, David B.; Kim, Do Heui; Lee, Jong H.; Peden, Charles HF

2012-04-30T23:59:59.000Z

10

Ni-Pt silicide formation through Ti mediating layers  

Science Conference Proceedings (OSTI)

With Ni"1"-"xPt"xSi, the variation in queue time between the final surface cleaning and Ni-Pt deposition represents a significant manufacturability issue. A short queue time is often difficult to maintain, leading to the formation of an oxide layer on ... Keywords: Mediated reaction, Nickel silicide, Oxidation, Titanium

Paul Besser; Christian Lavoie; Ahmet Ozcan; Conal Murray; Jay Strane; Keith Wong; Michael Gribelyuk; Yun-Yu Wang; Christopher Parks; Jean Jordan-Sweet

2007-11-01T23:59:59.000Z

11

CO adsorption and kinetics on well-characterized Pd films on Pt(111) in alkaline solutions  

DOE Green Energy (OSTI)

The electrochemistry of CO on a bare Pt(111) electrode as well as a Pt(111) electrode modified with pseudomorphic thin palladium films has been studied in alkaline solution by means of Fourier transform infrared (FTIR) spectroscopy. First Pd films were prepared and well characterized in UHV and subsequently transferred into the electrochemical cell for the registration of the voltammetric profiles. The charge corresponding to the formation of underpotentially deposited hydrogen (H{sub upd}) on these Pt(111)-xPd surfaces was established in sulfuric acid solution as a function of x (0 {le} x {le} 1 Pd monolayer (ML)). All subsequent measurements were then performed on electrochemically deposited palladium films using the above H{sub upd}-charge vs. Pd coverage relationship to evaluate the amount of electrochemically deposited palladium. FTIR spectra for CO adsorbed on one monolayer and a submonolayer coverage are compared to those of the unmodified Pt(111) surface, all surfaces having identical 2D lattice structures. Infrared absorption bands of CO bound on either Pt(111) or Pt(111)-1ML Pd are clearly distinguished. Spectra of CO adsorbed on Pd submonolayers show characteristic features of both CO bound to Pt and to Pd, indicating that on Pt(111)-xPd surfaces there is no coupling between Pt-CO{sub ad} and Pd-CO{sub ad} molecules. The kinetics of CO oxidation on these surfaces is determined either by rotating disk electrode (RDE) measurements or by FTIR spectroscopy, monitoring the CO{sub 3}{sup 2-} production. The oxidation of CO{sub ad} on Pt(111) and on Pd modified platinum surfaces starts at the same potential, ca. at 0.2 V. The oxidation rate is, however, considerably lower on the Pt(111)-xPd surfaces than on the Pt(111) surface. The kinetics of CO oxidation appears to be determined by the nature of adsorbed hydroxyl anions (OH{sub ad}), which are more strongly (less active) adsorbed on the highly oxophilic Pd atoms.

Arenz, M.; Stamenkovic, V.; Wandelt, K.; Ross, P.N.; Markovic, N.M.

2002-01-01T23:59:59.000Z

12

Study of bifunctional imidazolylphosphine ligands on Pd and Pt  

E-Print Network (OSTI)

Reaction between 2 and Pt(cod) 2 ……………………………………119 Figurewas purchased from Sigma Aldrich. Preparation of Pt(cod) 2 .Pt(cod) 2 was prepared according to the literature

Gong, Yi

2007-01-01T23:59:59.000Z

13

Pt/Pd electrocatalyst electrons for fuel cells  

DOE Patents (OSTI)

This invention relates to improved electrochemical cells and to novel electrodes for use therein. In particular, the present invention comprises a fuel cell used primarily for the consumption of impure hydrogen fuels containing carbon monoxide or carbonaceous fuels where the electrode in contact with the fuel is not substantially poisoned by carbon monoxide. The anode of the fuel cell comprises a Pd/Pt alloy supported on a graphitized or partially graphitized carbon material. Fuel cells which comprise as essential elements a fuel electrode, an oxidizing electrode, and an electrolyte between said electrodes are devices for the direct production of electricity through the electrochemical combustion of a fuel and oxidant. These devices are recognized for their high efficiency as energy conversion units, since unlike conventional combustion engines, they are not subject to the limitations of the Carnot heat cycle. It is the primary object of the present invention to provide an electrode having high electrochemical activity for an electrochemical cell. It is another object of the present invention to provide an electrode having an electro-catalyst which is highly resistant to the corrosive environment of an electrochemical cell.

Stonehart, P.

1981-11-03T23:59:59.000Z

14

Recent Advances in Pt Monolayer Electrocatalysts for Oxygen Reduction Reaction: Scale-up Synthesis, Structure, and Activity of Pt Shells on Pd Cores  

Science Conference Proceedings (OSTI)

We have established a scale-up synthesis method to produce gram-quantities of Pt monolayer electrocatalysts. The core-shell structure of the Pt/Pd/C electrocatalyst has been verified using the HAADF-STEM Z-contrast images, STEM/EELS, and STEM/EDS line profile analysis. The atomic structure of this electrocatalyst and formation of a Pt monolayer on Pd nanoparticle surfaces were examined using in situ EXAFS. The Pt mass activity of the Pt/Pd/C electrocatalyst for ORR is considerably higher than that of commercial Pt/C electrocatalysts. The results with Pt monolayer electrocatalysts may significantly impact science of electrocatalysis and fuel-cell technology, as they have demonstrated an exceptionally effective way of using Pt that can resolve problems of other approaches, including electrocatalysts inadequate activity and high Pt content.

Sasaki, K. [Brookhaven National Laboratory (BNL); Wang, J.X. [Brookhaven National Laboratory (BNL); Naohara, H. [Toyota Motor Corp.; Marinkovic, N. [University of Delaware; More, Karren Leslie [ORNL; Inada, H. [Hitachi High Technologies America; Adzic, R.R. [Brookhaven National Laboratory (BNL)

2010-01-01T23:59:59.000Z

15

Monte Carlo Simulations of Segregation in Pt-Ni Catalyst Nanoparticles  

E-Print Network (OSTI)

of Segregation in Pt-Ni Catalyst Nanoparticles Guofengsurface chemistry of catalyst nanoparticles (also called "Pt-Ni alloy is an electro-catalyst of interest in the air

Wang, Guofeng; Van Hove, Michel A.; Ross, Philip N.; Baskes, M.I.

2004-01-01T23:59:59.000Z

16

Shape Memory Response of NiTiHfPd High Strength and High ...  

Science Conference Proceedings (OSTI)

In this study, shape memory and superelastic properties of NiTiHfPd polycrystalline and single crystalline SMAs as functions of aging temperature and time were ...

17

Synthesis of Pt?Pd Core?Shell Nanostructures by Atomic Layer Deposition: Application in Propane Oxidative Dehydrogenation to Propylene  

Science Conference Proceedings (OSTI)

Atomic layer deposition (ALD) was employed to synthesize supported Pt?Pd bimetallic particles in the 1 to 2 nm range. The metal loading and composition of the supported Pt?Pd nanoparticles were controlled by varying the deposition temperature and by applying ALD metal oxide coatings to modify the support surface chemistry. Highresolution scanning transmission electron microscopy images showed monodispersed Pt?Pd nanoparticles on ALD Al2O3 - and TiO2 -modi?ed SiO2 gel. X-ray absorption spectroscopy revealed that the bimetallic nanoparticles have a stable Pt-core, Pd-shell nanostructure. Density functional theory calculations revealed that the most stable surface con?guration for the Pt? Pd alloys in an H2 environment has a Pt-core, Pd-shell nanostructure. In comparison to their monometallic counterparts, the small Pt?Pd bimetallic core?shell nanoparticles exhibited higher activity in propane oxidative dehydrogenation as compared to their physical mixture.

Lei, Y.; Liu, Bin; Lu, Junling; Lobo-Lapidus, Rodrigo J.; Wu, Tianpin; Feng, Hao; Xia, Xiaoxing; Mane, Anil U.; Libera, Joseph A.; Greeley, Jeffrey P.; Miller, Jeffrey T.; Elam, J. W.

2012-08-20T23:59:59.000Z

18

Surface segregation effects in electrocatalysis: Kinetics ofoxygen reduction reaction on polycrystalline Pt3Ni alloy surfaces  

DOE Green Energy (OSTI)

Effects of surface segregation on the oxygen reduction reaction (ORR) have been studied on a polycrystalline Pt3Ni alloy in acid electrolyte using ultra high vacuum (UHV) surface sensitive probes and the rotating ring disk electrode (RRDE) method. Preparation, modification and characterization of alloy surfaces were done in ultra high vacuum (UHV). Depending on the preparation method, two different surface compositions of the Pt3Ni alloy are produced: a sputtered surface with 75 % Pt and an annealed surface (950 K ) with 100 % Pt. The latter surface is designated as the 'Pt-skin' structure, and is a consequence of surface segregation, i.e., replacement of Ni with Pt atoms in the first few atomic layers. Definitive surface compositions were established by low energy ion scattering spectroscopy (LEISS). The cyclic voltammetry of the 'Pt-skin' surface as well as the pseudocapacitance in the hydrogen adsorption/desorption potential region is similar to a polycrystalline Pt electrode. Activities of ORR on Pt3Ni alloy surfaces were compared to polycrystalline Pt in 0.1M HClO4 electrolyte for the observed temperature range of 293 < T < 333 K. The order of activities at 333 K was: 'Pt-skin' > Pt3Ni (75% Pt) > Pt with the maximum catalytic enhancement obtained for the 'Pt-skin' being 4 times that for pure Pt. Catalytic improvement of the ORR on Pt3Ni and 'Pt-skin' surfaces was assigned to the inhibition of Pt-OHad formation (on Pt sites) versus polycrystalline Pt. Production of H2O2 on both surfaces were similar compared to the pure Pt. Kinetic analyses of RRDE data confirmed that kinetic parameters for the ORR on the Pt3Ni and 'Pt-skin' surfaces are the same as on pure Pt: reaction order, m=1, two identical Tafel slopes, activation energy, {approx} 21-25 kJ/mol. Therefore the reaction mechanism on both Pt3Ni and 'Pt-skin' surfaces is the same as one proposed for pure Pt i.e. 4e{sup -} reduction pathway.

Stamenkovic, V.; Schmidt, T.J.; Ross, P.N.; Markovic, N.M.

2002-11-01T23:59:59.000Z

19

Cluster Chemistry in Electron-Poor Ae-Pt-Cd Systems (Ae=Ca, Sr, Ba): (Sr,Ba)Pt2Cd4, Ca6Pt8Cd16, and Its Known Antitype Er6Pd16Sb8  

SciTech Connect

Three new ternary polar intermetallic compounds, cubic Ca6Pt8Cd16, and tetragonal (Sr, Ba)Pt2Cd4 have been discovered during explorations of the Ae–Pt–Cd systems. Cubic Ca6Pt8Cd16 (Fm-3m, Z = 4, a = 13.513(1) Å) contains a 3D array of separate Cd8 tetrahedral stars (TS) that are both face capped along the axes and diagonally bridged by Pt atoms to generate the 3D anionic network Cd8[Pt(1)]6/2[Pt(2)]4/8. The complementary cationic surface of the cell consists of a face-centered cube of Pt(3)@Ca6 octahedra. This structure is an ordered ternary variant of Sc11Ir4 (Sc6Ir8Sc16), a stuffed version of the close relative Na6Au7Cd16, and a network inverse of the recent Er6Sb8Pd16 (compare Ca6Pt8Cd16). The three groups of elements each occur in only one structural version. The new AePt2Cd4, Ae = Sr, Ba, are tetragonal (P42/mnm,Z = 2, a ? 8.30 Å, c ? 4.47 Å) and contain chains of edge-sharing Cd4 tetrahedra along c that are bridged by four-bonded Ba/Sr. LMTO-ASA and ICOHP calculation results and comparisons show that the major bonding (Hamilton) populations in Ca6Pt8Cd16 and Er6Sb8Pd16 come from polar Pt–Cd and Pd–Sb interactions, that Pt exhibits larger relativistic contributions than Pd, that characteristic size and orbital differences are most evident for Sb 5s, Pt8, and Pd16, and that some terms remain incomparable, Ca–Cd versus Er–Pd.

Samal, Saroj L. [Ames Laboratory; Gulo, Fakhili [Ames Laboratory; Corbett, John D. [Ames Laboratory

2013-02-18T23:59:59.000Z

20

Well-defined ultrathin Pd films on Pt(111): electrochemical preparation and interfacial chemistry  

E-Print Network (OSTI)

Well-defined ultrathin films of palladium, with coverages ranging from submonolayer, ?Pd = 0.5 monolayer (ML), to multilayer, ?P d = 8 ML, were electrochemically deposited on Pt(111) using potentiostatic and potentiodynamic methods. In both methods, between the coverage regimes studied, the growth of the Pd films follows the Stranski-Krastanov mechanism. The interfacial electrochemical properties associated with the film-to-bulk transition were characterized by conventional voltammetric techniques in combination with low-energy electron diffraction (LEED) and Auger electron spectroscopy (AES). The voltammetric peaks associated with H-atom adsorption and desorption on terrace sites indicate that the Pd electrodeposit starts to exhibit bulk-like properties at a coverage of 3 ML. Voltammetric cycling, in sulfuric acid solution, between the hydrogen evolution and the double-layer regions, was found to exert minimal influence on the annealing (smoothening) of the electrodeposited Pd films. However, cycling within the same potential region in the presence of bromide anions (at which Br- adsorption/Br desorption takes place) smoothens the initially rough Pd films essentially as well as high-temperature annealing. The influence of chemisorbed bromine on the anodic dissolution of Pd was also studied; this was for comparison with previous work on the anodic dissolution of Pd, in inert electrolyte, catalyzed by chemisorbed iodine. The present studies indicated that a small but measurable amount of bromine was desorbed along with dissolution of the Pd step atoms; bromine at the Pd terrace behaved identically to iodine in that the coverage of iodine is maintained regardless of the amount or origin of the of anodically stripped Pd. Atomically smooth, well-defined ultrathin Pd films were prepared by a constant potential deposition (CPD) method followed by multiple potential cycles, in dilute Brsolution, within the double-layer region and reductive removal of Brads, by simple emersion at a potential just before the hydrogen evolution reaction potential (EHER). A previously adapted method for the same purpose involved the chemisorption of iodine onto ultrathin PdCPD films, from dilute I- solution, followed by reductive desorption of Iads in iodide-free solution at pH 10 and at a potential just before EHER.

Park, Yeon Su

2003-05-01T23:59:59.000Z

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21

Characterizations Of Precipitate Phases In a Ti-Ni-Pd Alloy  

Science Conference Proceedings (OSTI)

Precipitates in the Ti46Ni37.5Pd16.5 alloy were investigated by electron diffraction and high-resolution scanning transmission electron microscopy. The phase content and stability were determined at several different temperatures and times. Aging at 400 C for an hour results in a new phase, which is consumed by P-phase at longer aging time. At 450 C, the new phase appears first, and then coexists with P-phase. At 500 C, the entire alloy transformed into the new phase. At 550 C, Ti3(Ni,Pd)4 phase begins to form.

Yang, Fan; Kovarik, Libor; Phillips, Patrick J.; Noebe, Ronald D.; Mills, M. J.

2012-06-01T23:59:59.000Z

22

Molecular beam epitaxy growth of exchange-biased PtMn/NiFe bilayers with a spontaneously ordered PtMn layer  

Science Conference Proceedings (OSTI)

We report the direct epitaxial growth of equiatomic ordered antiferromagnetic PtMn layers by molecular beam epitaxy. Such layers are used in giant magnetoresistance spin valve sensors as the antiferromagnetic pinning layer. Structural characterization and phase identification confirmed the spontaneous formation of the chemically ordered face-centered-tetragonal (L1{sub 0}) phase of PtMn with about 87.4% ordering. Based on the antiferromagnetic PtMn layer, we prepared exchange-biased PtMn/NiFe bilayers with various PtMn thicknesses. The exchange anisotropy field of the bilayer with NiFe grown on PtMn stabilizes at about 50 Oe beyond a PtMn thickness of 15 nm. Although the exchange anisotropy field is small compared to that of the polycrystalline system, the antiferromagnetic domain structure is stable over repetitive external magnetic field cycling and no training effect is observed.

Choi, Y. S.; Petford-Long, A. K.; Ward, R. C. C.; Fan, R.; Goff, J. P.; Hase, T. P. A. [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom); Department of Physics, University of Liverpool, Liverpool L69 7ZE (United Kingdom); Department of Physics, University of Durham, Durham DH1 3LE (United Kingdom)

2006-04-15T23:59:59.000Z

23

Ultrathin Co/Pt and Co/Pd superlattice films for MgO-based perpendicular magnetic tunnel junctions  

SciTech Connect

Ultrathin [Co/Pt]{sub n} and [Co/Pd]{sub n} superlattice films consisting of 0.14-0.20-nm-thick Co and Pt(Pd) layers were deposited by sputtering. A large perpendicular magnetic anisotropy [(3-9)x10{sup 6} ergs/cm{sup 3}] and an ideal square out-of-plane hysteresis loop were attained even for ultrathin superlattice films with a total thickness of 1.2-2.4 nm. The films were stable against annealing up to 370 deg. C. MgO-based perpendicular magnetic tunnel junctions with this superlattice layer as the free layer showed a relatively high magnetoresistance ratio (62%) and an ultralow resistance-area product (3.9 {Omega} {mu}m{sup 2}) at room temperature. The use of these films will enable the development of gigabit-scale nonvolatile memory.

Yakushiji, K.; Saruya, T.; Kubota, H.; Fukushima, A.; Nagahama, T.; Yuasa, S.; Ando, K. [Spintronics Research Center, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568 (Japan)

2010-12-06T23:59:59.000Z

24

Activity and Evolution of Vapor Deposited Pt-Pd Oxygen Reduction Catalysts for Solid Acid Fuel Cells  

SciTech Connect

The performance of hydrogen fuel cells based on the crystalline solid proton conductor CsH2PO4 is circumscribed by the mass activity of platinum oxygen reduction catalysts in the cathode. Here we report on the first application of an alloy catalyst in a solid acid fuel cell, and demonstrate an activity 4.5 times greater than Pt at 0.8 V. These activity enhancements were obtained with platinum-palladium alloys that were vapor-deposited directly on CsH2PO4 at 210 C. Catalyst mass activity peaks at a composition of 84 at% Pd, though smaller activity enhancements are observed for catalyst compositions exceeding 50 at% Pd. Prior to fuel cell testing, Pd-rich catalysts display lattice parameter expansions of up to 2% due to the presence of interstitial carbon. After fuel cell testing, a Pt-Pd solid solution absent of lattice dilatation and depleted in carbon is recovered. The structural evolution of the catalysts is correlated with catalyst de-activation.

Papandrew, Alexander B [ORNL; Chisholm, Calum R [ORNL; Zecevic, strahinja [LiOx, Inc., Pasadena, California 91106, United States; Veith, Gabriel M [ORNL; Zawodzinski, Thomas A [ORNL

2013-01-01T23:59:59.000Z

25

Hydrogen induced C-C, C-N, and C-S bond activation on Pt and Ni surfaces  

SciTech Connect

The work has focussed on hydrogen induced bond activation in adsorbed organic molecules and intermediates containin C-S and C-N and C-C bonds on Ni(100), Ni(111), and Pt(111) surfaces. Fluorescence Yield Near Edge Spectroscopy (FYNES) above the carbon K edge was used for adsorbed organic reactants and in-situ kinetic studies of bond activation. Results indicate that the activation is enhanced on Ni relative to Pt. Methylthiolate and methylamine adsorbed on Pt(111) were studied.

Gland, J.L.

1992-01-01T23:59:59.000Z

26

Hydrogen induced C-C, C-N, and C-S bond activation on Pt and Ni surfaces  

SciTech Connect

The work has focussed on hydrogen induced bond activation in adsorbed organic molecules and intermediates containin C-S and C-N and C-C bonds on Ni(100), Ni(111), and Pt(111) surfaces. Fluorescence Yield Near Edge Spectroscopy (FYNES) above the carbon K edge was used for adsorbed organic reactants and in-situ kinetic studies of bond activation. Results indicate that the activation is enhanced on Ni relative to Pt. Methylthiolate and methylamine adsorbed on Pt(111) were studied.

Gland, J.L.

1992-12-01T23:59:59.000Z

27

Final Technical Report: First Principles Investigations for the Ensemble Effects of PdAu and PtAu Bimetallic Nanocatalysts  

DOE Green Energy (OSTI)

Bimetallic surfaces with tunable chemical properties have attracted broad attention in recent years due to their ample potential for heterogeneous catalysis applications. The local chemical properties of constituents are strongly altered from their parent metals by 'ligand effect', a term encompassing the influences of charge transfer, orbital rehybridization and lattice strain. In comparison to the aforementioned, the 'ensemble effect' associated with particular arrangements of the active constituents have received much less attention, despite their notable importance towards the determination of reactivity and selectivity of bimetallic catalysts. We performed theoretical studies for understanding the ensemble effects on bimetallic catalysis: (i) simulations for the formation of different ensembles on PdAu and PtAu nanoclusters; (ii) studies of the size, shape, and substrate dependence of their electronic properties; and (iii) simulations for model reactions such as CO oxidation, methanol, ethylene and water dehydrogenation on PdAu and PtAu nanoclusters. In close collaboration with leading experimental groups, our theoretical research elucidated the fundamentals of Au based bimetallic nanocatalysts.

Ruqian Wu

2012-05-18T23:59:59.000Z

28

Enhancing hydrogen evolution activities in water splitting by tailoring Li+/Ni(OH){<_2}/Pt interfaces.  

DOE Green Energy (OSTI)

Improving the sluggish kinetics for the electrochemical reduction of water to molecular hydrogen in alkaline environments is one key to reducing the high overpotentials and associated energy losses in water-alkali and chlor-alkali electrolyzers. We found that a controlled arrangement of nanometer-scale Ni(OH){sub 2} clusters on platinum electrode surfaces manifests a factor of 8 activity increase in catalyzing the hydrogen evolution reaction relative to state-of-the-art metal and metal-oxide catalysts. In a bifunctional effect, the edges of the Ni(OH){sub 2} clusters promoted the dissociation of water and the production of hydrogen intermediates that then adsorbed on the nearby Pt surfaces and recombined into molecular hydrogen. The generation of these hydrogen intermediates could be further enhanced via Li{sup +}-induced destabilization of the HO-H bond, resulting in a factor of 10 total increase in activity.

Subbaraman, S.; Tripkovic, D.; Strmcnik, D.; Chang, K-C.; Uchimura, M.; Paulikas, A. P.; Stamenkovic, V.; Markovic, N. M. (Materials Science Division); ( NE); (Nissan Res. Ctr.)

2011-12-02T23:59:59.000Z

29

Pt effects in c-Ni(Al)/a-Al 2O3 adhesion  

Science Conference Proceedings (OSTI)

might potentially affect adhesion by noble-metal Pt and to quantify their .... over different interlayer planes and search for the minimum. Wsep that results from the

30

Suppression of the spin pumping in Pd/Ni{sub 81}Fe{sub 19} bilayers with nano-oxide layer  

SciTech Connect

We demonstrate that the spin pumping effect can be effectively suppressed with a nano-oxide layer. Spin pumping effect manifests itself by an enhancement of the Gilbert damping parameter in normal metal/ferromagnetic hetero-structures, while many spintronics devices prefer smaller damping parameter. Since the spin pumping effect is directly related with the spin dependent interface conductance, we can modify the spin pumping by altering the interface conductance with the nano-oxide layer. We prepared series of Pd/Ni{sub 81}Fe{sub 19} bilayers with different pausing time between Pd and Ni{sub 81}Fe{sub 19} depositions in order to control the interface conductance. The Gilbert damping parameters are determined from the line-width measurements in the ferromagnetic resonance spectra for each pausing time sample. They are 0.0490, 0.0296, 0.0278, and 0.0251 for 0, 6, 30, and 60 s pausing time, respectively. We find that the damping parameter of Pd/Ni{sub 81}Fe{sub 19} is almost recovered to one of the Cu/Ni{sub 81}Fe{sub 19} bilayer with 60 s pausing time, while the static magnetic properties are not noticeably changed.

Kim, Duck-Ho; Kim, Hong-Hyoun; You, Chun-Yeol [Department of Physics, Inha University, Namgu Incheon 402-751 (Korea, Republic of)

2011-08-15T23:59:59.000Z

31

Mechanisms Associated with Rumpling of Pt-Modified Beta-NiAl Coatings  

SciTech Connect

The formation of surface undulations (i.e. rumpling) at the bond coat/thermally grown oxide (TGO) interface has been shown to cause failure by spallation of the ceramic top coat in aero-turbine systems. Many mechanisms have been proposed concerning the cause of these surface distortions; however, there is little agreement on what may be the dominating cause of the rumpling behavior. Of there mechanisms, the reversible phase transformation from a cubic {beta}-NiAl structure to a face centered tetragonal (FCT) martensitic phase was of particular interest because of its ability to form surface rumpling in Pt-modified {beta} bulk alloys. However, the bulk alloys used in obtaining that result were simple ternary systems and not relevant to actual coating compositions as other alloying elements enter the coating due to coating/substrate interdiffusion at high temperature. In the current study, the depletion behavior of a commercial coating was studied. Compositions from the depletion path were determined and bulk alloys representing these coating compositions were prepared. The martensitic phase transformation was then characterized using DSC and XRD. The martensitic start temperature on cooling, Ms, was consistently found to be significantly lower than previously reported values (e.g. 530 C vs 100 C). Because of the low Ms temperature, the formation of the martensitic phase was concluded to be unnecessary for the occurrence of rumpling. However, cyclic exposure treatments at low temperature ({approx} 400 C) of bulk alloys and commercial coatings did show the detrimental effects of the phase transformation in the form of crack formation and propagation leading to eventual failure of the alloys. The current work also infers that the differences in coefficient of thermal expansion (CTE) mismatch between the coating and substrate are the dominating factor leading to rumpling. Dilatometry measurements were made on bulk alloys representing depleted coatings and the superalloy substrate to determine CTE as a function of temperature. Finally, simulations were completed to help determine the role of CTE mismatch. It was found that these results compared closely to those collected during experimental cyclic exposure treatments; although, modification to the current model were found to be needed in order to truly simulate rumpling.

Joseph Peter Henderkott

2007-12-01T23:59:59.000Z

32

Structure-Property Relationships for Ni-Ti-Pt High Temperature ...  

Science Conference Proceedings (OSTI)

Development of a SMA-Based Drive Unit for Prehension Orthoses to Support Disabled People · Effect of H in Metals and Alloys: An Application to bcc W and NiTi ...

33

Comparison of dc performance of Pt/Ti/Au- and Ni/Au-Gated AlGaN/GaN High Electron Mobility Transistors  

Science Conference Proceedings (OSTI)

We have demonstrated significant improvements of AlGaN/GaN High Electron Mobility Transistors (HEMTs) dc performance by employing Pt/Ti/Au instead of the conventional Ni/Au gate metallization. During off-state bias stressing, the typical critical voltage for HEMTs with Ni/Au gate metallization was ~ -45 to -65V. By sharp contrast, no critical voltage was observed for HEMTs with Pt/Ti/Au gate metallization, even up to -100V, which was the instrumental limitation in this experiment. After the off-state stressing, the drain current of Ni/Au gated-HEMTs decreased by~ 15%. For the Pt-gate HEMTs, no degradation of the drain current occurred and there were minimal changes in the Schottky gate characteristics for both forward and reverse bias conditions. The HEMTs with Pt/Ti/Au metallization showed an excellent drain on/off current ratio of 1.5 108. The on/off drain current ratio of Ni-gated HEMTs was dependent on the drain bias voltage and ranged from 1.2 107 at Vds=5V and 6 105

Liu, L. [University of Florida, Gainesville; Lo, C. F. [University of Florida; Kang, Tsung Sheng [University of Florida, Gainesville; Pearton, S. J. [University of Florida; Kravchenko, Ivan I [ORNL; Laboutin, O. [Kopin Corporation, Taunton, MA; Johnson, Wayne J. [Kopin Corporation, Taunton, MA; Ren, F. [University of Florida

2011-01-01T23:59:59.000Z

34

Catalyst and process development for hydrogen preparation from future fuel cell feedstocks. Quarterly progress report, October 1, 1979-December 31, 1979. [Pt/Rh, Ni/Rh, Ni/Pt/Rh, Ni, Ni/Ru, Ni/Pt, Ni/Co  

DOE Green Energy (OSTI)

Twelve steam reforming catalysts were evaluated using an autothermal reforming screening unit. Duplicate tests were run with two samples to determine test variability. The samples tested contained either base metals, precious metals, or combinations of base and precious metals. The test was capable of distinguishing among samples where gross variations in composition are the main factor; for example, catalysts containing 2% by weight precious metals are more active than catalysts containing 15% by weight nickel. The results show a decrease in hydrocarbon breakthrough as the weight of nickel charged to the constant volume reactor increases. A commercial nickel catalyst, G90C, appears slightly better than some Engelhard prepared samples of equal nickel concentrations due to the higher density of G90C. Visual observation of the used catalysts show that samples containing only precious metals (Pt/Rh) did not coke during the run. The samples containing only base metals (nickel, cobalt) were coked and were magnetic. Samples containing 14.5% nickel by weight with 0.5% precious metals by weight added were not coked, were not magnetic, and had a blue colored core as compared to the black core of the virgin samples. Some speculation about deactivation mechanisms based on these observations are made.

Yarrington, R M; Feins, I R; Hwang, H S; Mayer, C P

1980-01-01T23:59:59.000Z

35

Reactivity of Transition Metals (Pd, Pt, Cu, Ag, Au) toward Molecular Hydrogen Dissociation: Extended Surfaces versus Particles Supported on TiC(001) or Small Is Not Always Better and Large Is Not Always Bad  

DOE Green Energy (OSTI)

The reactivity of Pd{sub 4}, Pt{sub 4}, Cu{sub 4}, Ag{sub 4}, and Au{sub 4} clusters supported on TiC(001) toward molecular hydrogen dissociation has been studied by means of density functional based theory and periodic models and compared to that of the (111) and (001) surfaces. Pd{sub 4} and Pt{sub 4} interact rather strongly with the TiC(001) substrate, but the interaction of molecular hydrogen with the Pd{sub 4}/TiC and Pt{sub 4}/TiC systems is also very strong. As a consequence of the substantial admetal {leftrightarrow} carbide interactions, the adsorbed H{sub 2} molecule becomes more difficult to dissociate than on the corresponding extended (111) and (001) surfaces. Here, having a small supported particle does not lead to an enhanced chemical activity. On the contrary, for the Cu{sub 4}/TiC, Ag{sub 4}/TiC, and Au{sub 4}/TiC systems the combination of the small size of the particle and the polarization induced by the underlying carbide facilitates the dissociation of the hydrogen molecule with respect to the case of the extended surfaces. Here, the reduced size effectively enhances the activity of the supported particle. Thus, our results for the M(111), M(100), and M{sub 4}/TiC(001) systems show the complex interplay that can take place among the nature of the admetal, particle size effects, and support interactions.

Rodriguez, J.A.; Gomez, T.; Florez, E.; Illas, F.

2011-05-11T23:59:59.000Z

36

Reactivity of Transition Metals (Pd Pt Cu Ag Au) toward Molecular Hydrogen Dissociation: Extended Surfaces versus Particles Supported on TiC(001) or Small Is Not Always Better and Large Is Not Always Bad  

DOE Green Energy (OSTI)

The reactivity of Pd{sub 4}, Pt{sub 4}, Cu{sub 4}, Ag{sub 4}, and Au{sub 4} clusters supported on TiC(001) toward molecular hydrogen dissociation has been studied by means of density functional based theory and periodic models and compared to that of the (111) and (001) surfaces. Pd{sub 4} and Pt{sub 4} interact rather strongly with the TiC(001) substrate, but the interaction of molecular hydrogen with the Pd{sub 4}/TiC and Pt{sub 4}/TiC systems is also very strong. As a consequence of the substantial admetal {leftrightarrow} carbide interactions, the adsorbed H{sub 2} molecule becomes more difficult to dissociate than on the corresponding extended (111) and (001) surfaces. Here, having a small supported particle does not lead to an enhanced chemical activity. On the contrary, for the Cu{sub 4}/TiC, Ag{sub 4}/TiC, and Au{sub 4}/TiC systems the combination of the small size of the particle and the polarization induced by the underlying carbide facilitates the dissociation of the hydrogen molecule with respect to the case of the extended surfaces. Here, the reduced size effectively enhances the activity of the supported particle. Thus, our results for the M(111), M(100), and M{sub 4}/TiC(001) systems show the complex interplay that can take place among the nature of the admetal, particle size effects, and support interactions.

Rodriguez J. A.; Gomez T.; Florez E.; Illas F.

2011-06-16T23:59:59.000Z

37

Inhomogeneity and glass-forming ability in the bulk metallic glass Pd{sub 42.5}Ni{sub 7.5}Cu{sub 30}P{sub 20} as seen via x-ray spectroscopies  

Science Conference Proceedings (OSTI)

Core-level photoemission spectroscopy and anomalous x-ray scattering (AXS) measurements were performed for the Pd{sub 42.5}Ni{sub 7.5}Cu{sub 30}P{sub 20} (PNCP) excellent metallic glass to investigate the chemical nature and local atomic structure, and the results were compared to those in Pd{sub 40}Ni{sub 40}P{sub 20} and Pd{sub 40}Cu{sub 40}P{sub 20}. The P 2p core levels clearly separate into two states, indicating that the P atoms have two different chemical sites, which is a strong experimental proof for the existence of an elastic inhomogeneity. From the AXS close to the Pd K edge, a specific Pd-P-Pd atomic configuration was observed, which is related to the stable state in the P 2p core levels. All of the core levels measured in PNCP have the deepest binding energies among these glasses, indicating the most stable electronic states. Local structure around the P atoms is discussed by the AXS data and a metastable crystal appeared in a supercooled metallic alloy close to PNCP.

Hosokawa, S. [Center for Materials Research Using Third-Generation Synchrotron Radiation Facilities, Hiroshima Institute of Technology, Hiroshima 731-5193 (Japan); Physikalische Chemie, Fachbereich Chemie, Philipps Universitaet Marburg, D-35032 Marburg (Germany); Sato, H.; Nakatake, M. [Hiroshima Synchrotron Radiation Center, Hiroshima University, Higashi-Hiroshima 739-0046 (Japan); Ichitsubo, T.; Matsubara, E. [Department of Materials Science and Engineering, Graduate School of Engineering, Kyoto University, Kyoto 606-8501 (Japan); Happo, N. [Graduate School of Information Sciences, Hiroshima City University, Hiroshima 731-3194 (Japan); Berar, J.-F.; Boudet, N. [Institut Neel, CNRS, F-38042 Grenoble Cedex (France); Usuki, T. [Department of Material and Biological Chemistry, Faculty of Science, Yamagata University, Yamagata 990-8560 (Japan); Pilgrim, W.-C. [Physikalische Chemie, Fachbereich Chemie, Philipps Universitaet Marburg, D-35032 Marburg (Germany); Nishiyama, N. [R and D Institute of Metals and Composites for Future Industries, Sendai 980-8577 (Japan)

2009-11-01T23:59:59.000Z

38

Catalyst and process development for hydrogen preparation from future fuel cell feedstocks. Quarterly report, April 1-June 30, 1980. [Pt/Pd  

DOE Green Energy (OSTI)

Phase II of the contract, which involved catalyst preparation and evaluation, was nearly completed this quarter. Phase III, which calls for the design and construction of a fuel processor, was started. During the quarter, four types of tests were run on the small scale catalyst screening unit. The operating line for coke-free operations was found to be approximately between 0.41 to 0.44 O/sub 2//C level. Screening at lower O/sub 2//C levels led to problems with plugging. In other tests, increased severity for screening steam reforming catalysts was obtained by doubling the space velocity. Another series of tests were run to determine the gas composition from the catalytic partial oxidation (CPO) section and to evaluate two CPO catalysts. In the other series of tests, catalysts were aged for about 20 hours using a propane, steam, and air mixture before testing with No. 2 oil for another five hours. This latter test has been used to study Pt/Rh catalysts made with various supports. Differences were readily determined for Pt/Rh supported on alpha alumina and Pt/Rh supported on stabilized alumina. This test method will find continued use in evaluating metal-support interactions. Several samples must be evaluated by this method before aging runs are made in the larger unit. After leaching alumina from a used Pt/Rh catalyst, the x-ray diffraction pattern showed the presence of a Pt-Rh alloy in the metal residue. Experiments were run to show that the alloy was formed in the reactor during testing and not during catalyst preparation. A larger version of the ATR reactor has been designed and major components are on order. Completion of the construction phase is scheduled for the next quarter.

Yarrington, R M; Feins, I R; Hwang, H S

1980-07-01T23:59:59.000Z

39

Durable pd-based alloy and hydrogen generation membrane thereof  

SciTech Connect

A durable Pd-based alloy is used for a H.sub.2-selective membrane in a hydrogen generator, as in the fuel processor of a fuel cell plant. The Pd-based alloy includes Cu as a binary element, and further includes "X", where "X" comprises at least one metal from group "M" that is BCC and acts to stabilize the .beta. BCC phase for stability during operating temperatures. The metal from group "M" is selected from the group consisting of Fe, Cr, Nb, Ta, V, Mo, and W, with Nb and Ta being most preferred. "X" may further comprise at least one metal from a group "N" that is non-BCC, preferably FCC, that enhances other properties of the membrane, such as ductility. The metal from group "N" is selected from the group consisting of Ag, Au, Re, Ru, Rh, Y, Ce, Ni, Ir, Pt, Co, La and In. The at. % of Pd in the binary Pd--Cu alloy ranges from about 35 at. % to about 55 at. %, and the at. % of "X" in the higher order alloy, based on said binary alloy, is in the range of about 1 at. % to about 15 at. %. The metals are selected according to a novel process.

Benn, Raymond C. (Madison, CT); Opalka, Susanne M. (Glastonbury, CT); Vanderspurt, Thomas Henry (Glastonbury, CT)

2010-02-02T23:59:59.000Z

40

An analysis of the pull strength behaviors of fine-pitch, flip chip solder interconnections using a Au-Pt-Pd thick film conductor on Low-Temperature, Co-fired Ceramic (LTCC) substrates.  

Science Conference Proceedings (OSTI)

The assembly of the BDYE detector requires the attachment of sixteen silicon (Si) processor dice (eight on the top side; eight on the bottom side) onto a low-temperature, co-fired ceramic (LTCC) substrate using 63Sn-37Pb (wt.%, Sn-Pb) in a double-reflow soldering process (nitrogen). There are 132 solder joints per die. The bond pads were gold-platinum-palladium (71Au-26Pt-3Pd, wt.%) thick film layers fired onto the LTCC in a post-process sequence. The pull strength and failure modes provided the quality metrics for the Sn-Pb solder joints. Pull strengths were measured in both the as-fabricated condition and after exposure to thermal cycling (-55/125 C; 15 min hold times; 20 cycles). Extremely low pull strengths--referred to as the low pull strength phenomenon--were observed intermittently throughout the product build, resulting in added program costs, schedule delays, and a long-term reliability concern for the detector. There was no statistically significant correlation between the low pull strength phenomenon and (1) the LTCC 'sub-floor' lot; (2) grit blasting the LTCC surfaces prior to the post-process steps; (3) the post-process parameters; (4) the conductor pad height (thickness); (5) the dice soldering assembly sequence; or (5) the dice pull test sequence. Formation of an intermetallic compound (IMC)/LTCC interface caused by thick film consumption during either the soldering process or by solid-state IMC formation was not directly responsible for the low-strength phenomenon. Metallographic cross sections of solder joints from dice that exhibited the low pull strength behavior, revealed the presence of a reaction layer resulting from an interaction between Sn from the molten Sn-Pb and the glassy phase at the TKN/LTCC interface. The thick film porosity did not contribute, explicitly, to the occurrence of reaction layer. Rather, the process of printing the very thin conductor pads was too sensitive to minor thixotropic changes to ink, which resulted in inconsistent proportions of metal and glassy phase particles present during the subsequent firing process. The consequences were subtle, intermittent changes to the thick film microstructure that gave rise to the reaction layer and, thus, the low pull strength phenomenon. A mitigation strategy would be the use of physical vapor deposition (PVD) techniques to create thin film bond pads; this is multi-chip module, deposited (MCM-D) technology.

Uribe, Fernando R.; Kilgo, Alice C.; Grazier, John Mark; Vianco, Paul Thomas; Zender, Gary L.; Hlava, Paul Frank; Rejent, Jerome Andrew

2008-09-01T23:59:59.000Z

Note: This page contains sample records for the topic "ni pd pt" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

[Hydrogen induced C-C, C-N, and C-S bond activities on Pi and Ni surfaces]: Summary  

SciTech Connect

This document summarizes research applied to chemical bond activation studies. Topics summarized include: Carbon nitrogen bonds experimentation with aniline on Ni(111), Mi(100), and Pt(111) surfaces; carbon sulfur bonds experimentation with methanethiol, phenylthiol, and dimethyl disulfide on Pt(111) and Ni(111) surfaces; carbon-carbon bonds experimentation on Ni(100), Ni(111) and Pt(111) surfaces; and in-situ fluorescence yield near edge spectroscopy.

Gland, J.L.

1994-12-31T23:59:59.000Z

42

(Ni,Pt)Al Systems Measured by  

Science Conference Proceedings (OSTI)

... Haide Ruiz-Luna, Luis Alberto Cáceres-Díaz, John Edison García-Herrera, Juan Muñoz-Saldaña, Jose Luis Ortiz-Merino, Gerardo Trapaga-Martinez, Ricardo ...

43

Investigation of the electrocatalysis for oxygen reduction reaction by Pt and binary Pt alloys: an XRD, XAS and electrochemical study  

DOE Green Energy (OSTI)

Electrocatalysis for the oxygen reduction reaction (ORR) on five binary Pt alloy electrocatalysts (PtCr/C, PtMn/C, PtFe/C, PtCo/C and PtNi/C) supported on carbon have been investigated. The electrochemical characteristics for ORR in a proton conducting fuel cell environment has been correlated with the electronic and structural parameters determined under in situ conditions using XANES and EXAFS technique respectively. Results indicate that all the alloys possess higher Pt 5d band vacancies as compared to Pt/C. There is also evidence of lattice contraction in the alloys (supported by XRD results). Further, the Pt/C shows increase in Pt 5 d band vacancies during potential transitions from 0.54 to 0.84 V vs. RHE, which has been ration@ on the basis of OH type adsorption. In contrast to this, the alloys do not exhibit such an enhancement. Detailed EXAFS analysis supports the presence of OH species on Pt/C and its relative absence in the alloys. Correlation of the electrochemical results with bond distances and d-band vacancies show a volcano type behavior with the PtCr/C on top of the curve.

Mukerjee, S.; McBreen, J. [Brookhaven National Lab., Upton, NY (United States); Srinivasan, S. [Texas A and M Univ., College Station, TX (United States). Texas Engineering Experiment Station

1995-12-31T23:59:59.000Z

44

Fuel cell with Pt/Pd electrocatalyst electrode  

DOE Patents (OSTI)

An electrode for use in a phosphoric acid fuel cell comprising a graphitized or partially graphitized carbon support having a platinum/palladium electrocatalyst thereon. Preferably, the platinum/palladium catalyst comprises 20 to 65 weight percent palladium.

Stonehart, Paul (Madison, CT)

1983-01-01T23:59:59.000Z

45

Method for the prediction of the hydriding thermodynamics of ternary PD-based alloys.  

DOE Green Energy (OSTI)

A method has been developed to calculate the hydriding thermodynamics of ternary Pd-X-Y systems, where X and Y are substitutional alloying elements, by using the properties of the binary Pd-X and Pd-Y systems. Experimental data was collected on the Pd-Rh-Co system to test the validity of this method. Hydrogen pressure-composition isotherms of several binary Pd-Rh and Pd-Co alloys and Pd-Rh-Co ternary alloys were measured to determine the thermodynamics of hydrogen absorption, hydride formation and decomposition, and hydrogen capacity. Good agreement between the calculated and measured values for the ternary Pd-Rh-Co system, in the dilute alloying regime (< 10 at.% total alloying additions), was obtained using our method. Examining literature results on other ternary Pd-X-Y systems checked the universality of this method. Again, the method succeeds in predicting the hydriding thermodynamics for both lattice contracted and lattice expanded alloy systems, Pd-Ni-Rh and Pd-Ag-Y respectively.

Teter, D. F. (David F.); Mauro, M. E. (Michael Ernest)

2001-01-01T23:59:59.000Z

46

Chemical interactions in multimetal/zeolite catalysts  

SciTech Connect

This report treats four subject areas: PtCu/NaY and Pd/Cu/NaY catalysts; reducibility of Ni in PdNi/NaY catalysts; CO hydrogenation over PdNi/NaY catalysts; and PdFe/NaY, Ga/H-ZSM5 and PtGa/H-ZSM5 catalysts.

Sachtler, W.M.H.

1992-02-07T23:59:59.000Z

47

High Aspect Ratio Nano-Structured Pt-based PEM Fuel Cell Catalysts...  

NLE Websites -- All DOE Office Websites (Extended Search)

or * nanoplates - Ni, Co, and Fe have been selected as V.D.14 High Aspect Ratio Nano-Structured Pt-Based PEM Fuel Cell Catalysts Table 1. Technical Targets for...

48

Carbon-Supported bimetallic Pd-Fe catalysts for vapor-phase hydrodeoxygenation of guaiacol  

Science Conference Proceedings (OSTI)

Abstract Carbon supported metal catalysts (Cu/C, Fe/C, Pd/C, Pt/C, PdFe/C and Ru/C) have been prepared, characterized and tested for vapor-phase hydrodeoxygenation (HDO) of guaiacol (GUA) at atmospheric pressure. Phenol was the major intermediate on all catalysts. Over the noble metal catalysts saturation of the aromatic ring was the major pathway observed at low temperature (250 °C), forming predominantly cyclohexanone and cyclohexanol. Substantial ring opening reaction was observed on Pt/C and Ru/C at higher reaction temperatures (e.g., 350 °C). Base metal catalysts, especially Fe/C, were found to exhibit high HDO activity without ring-saturation or ring-opening with the main products being benzene, phenol along with small amounts of cresol, toluene and trimethylbenzene (TMB). A substantial enhancement in HDO activity was observed on the PdFe/C catalysts. Compared with Fe/C, the yield to oxygen-free aromatic products (i.e., benzene/toluene/TMB) on PdFe/C increased by a factor of four at 350 °C, and by approximately a factor of two (83.2% versus 43.3%) at 450 °C. The enhanced activity of PdFe/C is attributed to the formation of PdFe alloy as evidenced by STEM, EDS and TPR.

Sun, Junming; Karim, Ayman M.; Zhang, He; Kovarik, Libor; Li, Xiaohong S.; Hensley, Alyssa; McEwen, Jean-Sabin; Wang, Yong

2013-10-01T23:59:59.000Z

49

Oxygen Reduction Activity of PtxNi1-x Alloy Nanoparticles on Multiwall Carbon Nanotubes  

E-Print Network (OSTI)

PtxNi1 - x nanoparticles (Pt:Ni; 1:0, 4:1, 3:1 and 0.7:1) of ~5 nm, were synthesized on carboxylic acid-functionalized multiwall carbon nanotubes (PtxNi1 - x NPs/MWNT). The oxygen reduction reaction (ORR) activity measurements ...

Kim, Junhyung

50

Aniline hydrogenolysis on the Pt(111) single crystal surface: Mechanisms for C-N bond activation  

SciTech Connect

Hydrogenolysis of C-N bond on transition metals is a crucial step in hydrodenitrogenation (HDN) reactions. Despite the overall complexity of HDN processes, the details of important surface reactions can be characterized using model reactions of organonitrogen compounds on single crystal model catalysts. The structure and reactivity of well characterized aniline monolayers on the Pt(111) surface both in vacuum and in the presence of hydrogen is discussed here. Adsorption and reactions of aniline were studied by Gland and Somorjai on the Pt(111) and Pt(100) surfaces, and more recently by Benziger`s group on the Ni(111) and Ni(100) surfaces. On both Pt and Ni surfaces, aniline {pi} bonds through the aromatic ring with its ring parallel to the substrate surface.

Huang, S.X.; Gland, J.L. [Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Chemistry; Fischer, D.A. [Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Chemistry]|[National Inst. of Standards and Technology, Gaithersburg, MD (United States). Materials Dept.

1993-12-31T23:59:59.000Z

51

ALTERNATIVE MATERIALS TO PD MEMBRANES FOR HYDROGEN PURIFICATION  

DOE Green Energy (OSTI)

Development of advanced hydrogen separation membranes in support of hydrogen production processes such as coal gasification and as front end gas purifiers for fuel cell based system is paramount to the successful implementation of a national hydrogen economy. Current generation metallic hydrogen separation membranes are based on Pd-alloys. Although the technology has proven successful, at issue is the high cost of palladium. Evaluation of non-noble metal based dense metallic separation membranes is currently receiving national and international attention. The focal point of the reported work was to evaluate two different classes of materials for potential replacement of conventional Pd-alloy purification/diffuser membranes. Crystalline V-Ni-Ti and Amorphous Fe- and Co-based metallic glass alloys have been evaluated using both electrochemical and gaseous hydrogen permeation testing techniques..

Adams, T; Paul Korinko, P

2007-11-13T23:59:59.000Z

52

ALTERNATIVE MATERIALS TO PD MEMBRANES FOR HYDROGEN PURIFICATION  

DOE Green Energy (OSTI)

Development of advanced hydrogen separation membranes in support of hydrogen production processes such as coal gasification and as front end gas purifiers for fuel cell based system is paramount to the successful implementation of a national hydrogen economy. Current generation metallic hydrogen separation membranes are based on Pd-alloys. Although the technology has proven successful, at issue is the high cost of palladium. Evaluation of non-noble metal based dense metallic separation membranes is currently receiving national and international attention. The focal point of the reported work was to evaluate two different classes of materials for potential replacement of conventional Pd-alloy purification/diffuser membranes. Crystalline V-Ni-Ti and Amorphous Fe- and Co-based metallic glass alloys have been evaluated using gaseous hydrogen permeation testing techniques.

Korinko, P; T. Adams

2008-09-12T23:59:59.000Z

53

X-ray Photoelectron Spectroscopy and Kinetic Study: Pt-Group Metals and Bimetallic Surfaces  

E-Print Network (OSTI)

Pt-group metals were some of the first metals to be studied as catalysts for industrial use. The goal of these studies was to ascertain a fundamental understanding of CO oxidation and acetylene cyclotrimerization reactions on Ptgroup metals. A further goal was to determine the optimal conditions for each reaction. CO oxidation on Rh(111),Pt(100), and Pd(100) was scrutinized on various oxide surfaces from chemisorbed to bulk metal oxides. Low pressure reactions on Rh(111) reveal the highest activity was a CO uninhibited surface with oxidation revealed that only oxidation reactions on Pd(100) show oxygen penetration after CO has been consumed; however, during the highest activity XPS found only chemisorbed species. The cyclotrimerization of acetylene to benzene is another reaction found in industry typically carried out on Pd. The active site is considered to be a 7 atom configuration with 6 atoms surrounding a central atom. By adding relatively catalytically inert Au atoms to the active Pd(111) surface the acetylene coupling activity is enhanced. Cyclization activity is a function of the surface composition and the surface structure. A single Pd atom surrounded by six Au atoms is found to have the highest activity at 300K for acetylene cyclotrimerization.

Gath, Kerrie K.

2008-12-01T23:59:59.000Z

54

H Diffusion through Partially Internally Oxidized Pd-alloy Membranes (U)  

DOE Green Energy (OSTI)

In 1998 Kirchheim et al remarked that ''to their knowledge, experimental results on the diffusion of hydrogen through multi-layers have not yet been reported'' [1]. Their research dealt with diffusion through ultra-thin multi-layers of Nb/Pd which they followed electrochemically using a time-lag method. Their results were somewhat uncertain in that no final conclusion about any effect of the internal interfaces could be reached. Very recently Yamakawa et al [2] investigated Pd/Fe and Pd/Ni multilayers at 378-625 K and found no strong influence of the interfaces, however, there was grain boundary diffusion for the Pd/Ni layers and retardation, possibly due to dislocation trapping. Takano et al [3] studied H diffusion through thin layers of Pd, Ni, or Cu deposited electrochemically on Fe and concluded that complications are introduced by thin films perhaps H trapping at vacancies as the thickness of the layer decreases to very small values. Holleck [4] measured H diffusion through mm thick Pd{sub 0.75}Ag{sub 0.25}/Ta/Pd{sub 0.75}Ag{sub 0.25} layers in the gas phase from 540-873 K and determined D{sub H,Ta} from the overall diffusion constant and the known D{sub H,alloy}; he concluded that the interface did not play a significant role at these temperatures. As in Holleck's, the present research does not concern very thin multi-layers but macroscopic ones, in this case, prepared by internal oxidation. The measurements will be carried out at a lower temperature than Holleck's and with a variety of layer thicknesses. Most previous investigations have employed electrochemical time-lag methods [1,3,5,6] at ambient temperature and have assumed that the solubilities at the interfaces are in the ideal range. To our knowledge, an investigation of diffusion through layers prepared by internal oxidation has not been carried out. Partial internal oxidation of Pd-M alloys leads to outer layers of Pd containing M oxide precipitates while the inner layer remains unoxidized Pd-M alloy. The alloy employed in this research is Pd{sub 0.96}Al{sub 0.04} which was chosen because the authors have had extensive experience with its internal oxidation [7,8] and it has been shown that internally oxidized Pd-Al alloys are more resistant to poisoning by CO than pure Pd [9]. The specific Al content was chosen in order for it to be large enough for the alloy to have a significantly lower permeability than Pd but small enough to internally oxidize. The diffusion results may give some information about internal oxidation.

Wang, D.; Flanagan, Ted B.; Shanahan, K. L.

2005-10-01T23:59:59.000Z

55

Bimetallic IrNi Core Platinum Monolayer Shell Electrocatalysts for the Oxygen Reduction Reaction  

DOE Green Energy (OSTI)

We synthesized a low-Pt content electrocatalyst consisting of a Pt monolayer placed on carbon-supported thermally treated IrNi core-shell structured nanoparticles using galvanic displacement of a Cu monolayer deposited at underpotentials. The Pt mass activity of the Pt{sub ML}/IrNi/C electrocatalyst obtained in a scale-up synthesis is approximately 3 times higher than that of the commercial Pt/C electrocatalyst. The electronic and geometrical effects of the IrNi substrate on the Pt monolayer result in its higher catalytic activity than that of Pt nanoparticles. The structure and composition of the core-shell nanoparticles were verified using transmission electron microscopy and in situ X-ray absorption spectroscopy, while a potential cycling test was employed to confirm the stability of the electrocatalyst. Our experimental results, supported by the density functional calculations using a sphere-like model, demonstrate an effective way of using Pt that can resolve key problems of cathodic oxygen reduction hampering fuel cell commercialization.

Kuttiyiel K. A.; Sasaki, K.; Choi, Y.M.; Su, D.; Liu, P.; Adzic, R.R.

2012-01-01T23:59:59.000Z

56

(Ni,Pt)Ti High Temperature Shape Memory Alloys  

Science Conference Proceedings (OSTI)

About this Abstract. Meeting, Materials Science & Technology 2011. Symposium, Shape Memory Alloys. Presentation Title, Phase Field Modeling of P-Phase ...

57

Overall Photocatalytic Water Splitting with NiOx-SrTiO3 – A Revised Mechanism  

Science Conference Proceedings (OSTI)

NiOx (0 water splitting under UV light. The established mechanism for this and many other NiOx containing catalysts assumes water oxidation to occur at the early transition metal oxide and water reduction at NiOx. Here we show that NiOx-STO is more likely a three component Ni-STO-NiO catalyst, in which STO absorbs the light, Ni reduces protons, and NiO oxidizes water. This interpretation is based on systematic H2/O2 evolution tests of appropriately varied catalyst compositions using oxidized, chemically and photochemically added nickel and NiO nanoparticle cocatalysts. Surface photovoltage (SPV) measurements reveal that Ni(0) serves as an electron trap (site for water reduction) and that NiO serves as a hole trap (site for water oxidation). Electrochemical measurements show that the overpotential for water oxidation correlates with NiO content, whereas the water reduction overpotential depends on Ni content. Photodeposition experiments with NiCl2 and H2PtCl6 on NiO-STO show that electrons are available on the STO surface, not on the NiO particles. Based on photoelectrochemistry, both NiO and Ni particles suppress the Fermi level in STO, but the effect of this shift on catalytic activity is not clear. Overall, the results suggest a revised role for NiO in NiOx-STO and in many other nickel-containing water splitting systems, including NiOx-La:KTaO3, and many layered perovskites.

Townsend, Troy K.; Browning, Nigel D.; Osterloh, Frank

2012-11-01T23:59:59.000Z

58

Oxygen Reduction on Well-Defined Core-Shell Nanocatalysts: Particle Size, Facet, and Pt Shell Thickness Effects  

DOE Green Energy (OSTI)

We examined the effects of the thickness of the Pt shell, lattice mismatch, and particle size on specific and mass activities from the changes in effective surface area and activity for oxygen reduction induced by stepwise Pt-monolayer depositions on Pd and Pd{sub 3}Co nanoparticles. The core?shell structure was characterized at the atomic level using Z-contrast scanning transmission electron microscopy coupled with element-sensitive electron energy loss spectroscopy. The enhancements in specific activity are largely attributed to the compressive strain effect based on the density functional theory calculations using a nanoparticle model, revealing the effect of nanosize-induced surface contraction on facet-dependent oxygen binding energy. The results suggest that moderately compressed (111) facets are most conducive to oxygen reduction reaction on small nanoparticles and indicate the importance of concerted structure and component optimization for enhancing core?shell nanocatalysts activity and durability.

Wang, J.X.; Inada, H.; Wu, L.; Zhu, Y.; Choi, Y.; Liu, P.; Zhou, W.-P.; Adzic, R.R.

2009-11-09T23:59:59.000Z

59

EXAMINATION OF 80 DEGREES C DESORPTION ISOTHERMS OFTRITIUM AGED PD/K AND LANA.75  

Science Conference Proceedings (OSTI)

Metal hydrides, specifically Pd deposited on kieselguhr (Pd/k) and LaNi{sub 4.25}Al{sub 0.75} (LANA.75), have been used at the Savannah River Site for almost twenty years for hydrogen isotope separation and storage. Radiolytic decay of tritium to helium-3 in the metal matrix causes three classic changes in the performance of the hydride: the plateau pressure decreases, the plateau slope increases, and a heel forms, reducing the reversible capacity of the hydride. Deuterium and tritium isotherms were collected on the virgin materials, only tritium isotherms were collected at approximately 2 years, and both deuterium and tritium isotherms were collected at approximately 3.5 years of quiescent aging. Points of interest include those mentioned above as well as the effects of cycling the materials. The methods and results are presented.

Staack, G; Kirk Shanahan, K; Tom Walters, T; Roger Pilgrim, R

2007-08-28T23:59:59.000Z

60

Improved Off-State Stress Critical Voltage on AlGaN/GaN High Electron Mobility Transistors Utilizing Pt/Ti/Au Based Gate Metallization  

Science Conference Proceedings (OSTI)

The critical voltage for degradation of AlGaN/GaN high electron mobility transistors (HEMTs) employed with the Pt/Ti/Au gate metallization instead of the commonly used Ni/Au was significantly increased during the off-state stress. The typical critical voltage for HEMTs with Ni/Au gate metallization was around -60V. By sharp contrast, no critical voltage was observed for the HEMTs with Pt/Ti/Au gate metallization, even up to -100V, which was the instrumental limitation in this experiment. Both Schottky forward and reverse gate characteristics of the Ni/Au degraded once the gate voltage passed the critical voltage of around -60V. There was no degradation exhibited for the HEMTs with Pt-gated HEMTs.

Lo, C. F. [University of Florida; Liu, L. [University of Florida, Gainesville; Kang, Tsung Sheng [University of Florida, Gainesville; Davies, Ryan [University of Florida; Gila, Brent P. [University of Florida, Gainesville; Pearton, S. J. [University of Florida; Kravchenko, Ivan I [ORNL; Laboutin, O. [Kopin Corporation, Taunton, MA; Cao, Yu [Kopin Corporation, Taunton, MA; Johnson, Wayne J. [Kopin Corporation, Taunton, MA; Ren, F. [University of Florida

2011-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "ni pd pt" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
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61

AcqGuide9pt1.doc | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

pt1.doc&0; AcqGuide9pt1.doc&0; AcqGuide9pt1.doc&0; More Documents & Publications Chapter 9 - Contracting Qualifications AcqGuide3pt1.doc&0; OPAM Policy Acquisition Guides...

62

Characterization of Ce-Pd(111) and Ce-Pd(110) surface alloys  

SciTech Connect

Cerium-palladium surface alloys have been studied by x-ray and ultraviolet photoelectron spectroscopy (XPS), low energy electron diffraction (LEED), and photoemission electron microscopy. Desorption of CO has been studied by temperature programed desorption spectroscopy. Thin layers of Ce were deposited on Pd(111) and Pd(110) single crystal substrates to form surface alloys upon annealing to 1000 K. An enrichment of Pd at the surface is observed and the work functions of the surface alloys are found to be 0.2-0.6 eV less than the value for the bare Pd substrate, which are substantially larger than the values for the as-deposited Ce-Pd samples. Several different LEED patterns were observed depending on the annealing temperature. The estimated Ce valence from XPS was found to be in the range from 3.16 to 3.22 for the surface alloys after annealing.

Tollefsen, H.; Berstad, L. J.; Raaen, S. [Physics Department, Norwegian University of Science and Technology (NTNU), N-7491 Trondheim (Norway)

2007-09-15T23:59:59.000Z

63

Electrodeposition of ultrathin Pd, Co and Bi films on well-defined noble-metal electrodes: studies by ultrahigh vacuum-electrochemistry (UHV-EC)  

E-Print Network (OSTI)

Three illustrative cases involving the electrodeposition of ultrathin metal films of varying reactivities onto noble-metal substrates were investigated: (i) Pd on Pt(111), a noble admetal on a noble-metal surface; (ii) Bi on Pd(111), a less noble admetal on a noble-metal surface; and (iii) Co on polycrystalline Pd and Pd(111), a reactive metal on a noble-metal surface. The interfacial electrochemistry of these prototypical systems was characterized using a combination of electrochemical methods (voltammetry and coulometry) and ultrahigh vacuum electron spectroscopies (Auger electron spectroscopy, AES; low energy electron diffraction, LEED; and X-ray photoelectron spectroscopy, XPS). Potential-controlled adsorption-desorption cycles of aqueous bromide exerted surface smoothening effects on ultrathin Pd films with defect sites (steps). This procedure, dubbed as electrochemical (EC) annealing, constituted a nonthermal analogue to conventional annealing. EC-annealed ultrathin Pd films exhibited long-range surface order and remained free of oxygen adspecies. Pdadatoms occupying step-sites were selectively dissolved and/or rearranged to assume equilibrium positions in a well-ordered (1x1) film. Electrodeposition of Co was found to be highly surface-structuresensitive. While virtually no Co electrodeposition transpired on a clean Pd(111) surface, Co was voltammetrically deposited on (i) a Pd(111) electrode roughened by oxidation-reduction cycles; and (ii) thermally annealed polycrystalline Pd, which is a composite of the (111) and (100) facets. Electrodeposition of Co was also observed to be kinetically hindered and slow potential scan rates (0.1 mV/s) were required. Well-defined ultrathin Bi films were potentiostatically electrodeposited onto Pd(111); a Stranski-Krastanov growth mode was indicated. The electrochemical reactivity of ultrathin Bi films was characterized using two surface probes: aqueous iodide and D-glucose. (i) Exposure of the prepared Bi adlayers (��Bi 0.33) to aqueous iodide gave rise to (�3x�7) I-on-Bi superlattice. The same superlattice was obtained if Bi was electrodeposited onto Pd(111)(�3x�3)R30o-I. (ii) With respect to electrooxidation of D-glucose on Pd(111), the presence of Bi adlayers inhibited the by-product-induced "surface poisoning" of Pd(111) but reduced its electrocatalytic efficiency.

Baricuatro, Jack Hess L

2006-08-01T23:59:59.000Z

64

THE EFFECT OF CO ON HYDROGEN PERMEATION THROUGH PD AND INTERNALLY OXIDIZED AND UN-OXIDIZED PD ALLOY MEMBRANES  

DOE Green Energy (OSTI)

The H permeation of internally oxidized Pd alloy membranes such as Pd-Al and Pd-Fe, but not Pd-Y alloys, is shown to be more resistant to inhibition by CO(g) as compared to Pd or un-oxidized Pd alloy membranes. The increased resistance to CO is found to be greater at 423 K than at 473 K or 523 K. In these experiments CO was pre-adsorbed onto the membranes and then CO-free H{sub 2} was introduced to initiate the H permeation.

Shanahan, K.; Flanagan, T.; Wang, D.

2010-10-20T23:59:59.000Z

65

Hydrogen Permeability of Mulitphase V-Ti-Ni Metallic Membranes  

DOE Green Energy (OSTI)

Development of advanced hydrogen separation membranes in support of hydrogen production processes such as coal gasification and as front end gas purifiers for fuel cell based system is paramount to the successful implementation of a national hydrogen economy. Current generation metallic hydrogen separation membranes are based on Pd-alloys. Although the technology has proven successful, at issue is the high cost of palladium. Evaluation of non-noble metal based dense metallic separation membranes is currently receiving national and international attention. The focal point of the reported work was to evaluate a Group 5A-Ta, Nb, V-based alloy with respect to microstructural features and hydrogen permeability. Electrochemical hydrogen permeation testing of the V-Ti-Ni alloy is reported herein and compared to pure Pd measurements recorded as part of this same study. The V-Ti-Ni was demonstrated to have a steady state hydrogen permeation rate an order of magnitude higher than the pure Pd material in testing conducted at 22 C.

Adams, T. M.; Mickalonis, J.

2005-10-18T23:59:59.000Z

66

Cu-Ni  

Science Conference Proceedings (OSTI)

... Ternary Fe-Cu-Ni many-body potential to model reactor pressure vessel ... alloy, This file was provided by Giovanni Bonny (Nuclear Materials Science ...

2013-07-06T23:59:59.000Z

67

PT-Rotations, PT-Spherical Harmonics and the PT-Hydrogen Atom  

E-Print Network (OSTI)

We have constructed a set of non-Hermitian operators that satisfy the commutation relations of the SO(3)-Lie algebra. It is shown that this operators generate rotations in the configuration space and not in the momentum space but in a modified non-Hermitian momentum space. This generators are related with a new type of spherical harmonics that result to be PT-orthonormal. Additionally, we have shown that this operators represent conserved quantities for a non-Hermitian Hamiltonian with an additional complex term. As a particular case, the solutions of the corresponding PT-Hydrogen atom that includes a complex term are obtained, and it is found that a non-Hermitian Runge-Lenz vector is a conserved quantity. In this way, we obtain a set of non-Hermitian operators that satisfy the SO(4)-Lie algebra.

Juan M. Romero; R. Bernal-Jaquez; O. Gonzalez-Gaxiola

2010-01-11T23:59:59.000Z

68

Examination of 80 deg. C desorption isotherms of tritium aged Pd/k and LANA.75  

Science Conference Proceedings (OSTI)

Metal hydrides, specifically Pd deposited on kieselguhr (Pd/k) and LaNi{sub 4.25}Al{sub 0.75} (LANA.75), have been used at the Savannah River Site for almost twenty years for hydrogen isotope separation and storage. Radiolytic decay of tritium to helium-3 in the metal matrix causes three classic changes in the performance of the hydride: the plateau pressure decreases, the plateau slope increases, and a heel forms, reducing the reversible capacity of the hydride. Deuterium and tritium isotherms were collected on the virgin materials, only tritium isotherms were collected at approximately 2 years, and both deuterium and tritium isotherms were collected at approximately 3.5 years of quiescent aging at 26 deg. C. Each sample was loaded to 0.5-0.6 T/M prior to each aging period. Points of interest include comparisons of each sample at different aging periods and isotope effects on aged hydride isotherms. Partial restoration of thermodynamic properties by sample cycling has been observed in LANA. 75, though not previously reported in Pd. The methods and results are presented. (authors)

Staack, G. C.; Shanahan, K. L.; Walters, R. T.; Pilgrim, R. D. [Savannah River National Laboratory, Aiken, SC 29808 (United States)

2008-07-15T23:59:59.000Z

69

Direct Determination of the Ionization Energies of PtC, PtO, and PtO2 with VUVRadiation  

SciTech Connect

Photoionization efficiency curves were measured for gas-phase PtC, PtO, and PtO2 using tunable vacuum ultraviolet (VUV) radiation at the Advanced Light Source. The molecules were prepared by laser ablation of a platinum tube, followed by reaction with CH4 or N2O and supersonic expansion. These measurements providethe first directly measured ionization energy for PtC, IE(PtC) = 9.45 +- 0.05 eV. The direct measurement also gives greatly improved ionization energies for the platinum oxides, IE(PtO) = 10.0 +- 0.1 eV and IE(PtO2) = 11.35 +- 0.05 eV. The ionization energy connects the dissociation energies of the neutral and cation, leading to greatly improved 0 K bond dissociation energies for the neutrals: D0(Pt-C) = 5.95 +- 0.07 eV, D0(Pt-O)= 4.30 +- 0.12 eV, and D0(OPt-O) = 4.41 +- 0.13 eV, as well as enthalpies of formation for the gas-phase molecules Delta H0 f,0(PtC(g)) = 701 +- 7 kJ/mol, Delta H0f,0(PtO(g)) = 396 +- 12 kJ/mol, and Delta H0f,0(PtO2(g)) = 218 +- 11 kJ/mol. Much of the error in previous Knudsen cell measurements of platinum oxide bond dissociation energies is due to the use of thermodynamic second law extrapolations. Third law values calculated using statistical mechanical thermodynamic functions are in much better agreement with values obtained from ionization energies and ion energetics. These experiments demonstrate that laser ablation production with direct VUV ionization measurements is a versatile tool to measure ionization energies and bond dissociation energies for catalytically interesting species such as metal oxides and carbides.

Citir, Murat; Metz, Ricardo B.; Belau, Leonid; Ahmed, Musahid

2008-07-21T23:59:59.000Z

70

Pd modified Au on carbon as an effective and durable catalyst for the direct oxidation of HMF to FDCA  

Science Conference Proceedings (OSTI)

We show that the modification of a gold/carbon catalyst with Pt or Pd produces stable and recyclable catalysts for the selective oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA). This finding is a significant advance over current conversion technology because of the technological importance of FDCA. Indeed, FDCA has been identified as one of twelve potential building blocks for the production of value added chemicals derived from biosources.1 FDCA is a potential replacement source of terephthalic acid, the monomer presently used for the production of polyethylene terephthalate (PET) and derived from hydrocarbon sources.2

Villa, Alberto [Universita di Milano, Italy; Schiavoni, Marco [University of Milan and INFN, Milano, Italy; Campisi, Sebastiano [University of Milan and INFN, Milano, Italy; Veith, Gabriel M [ORNL; Prati, Laura [Universita di Milano, Italy

2013-01-01T23:59:59.000Z

71

The Office of Proliferation Detection (PD) | National Nuclear...  

National Nuclear Security Administration (NNSA)

Proliferation Detection (PD) | National Nuclear Security Administration Our Mission Managing the Stockpile Preventing Proliferation Powering the Nuclear Navy Emergency Response...

72

Neutron Powder Diffraction of the Mg6Pd and Mg6Pd + Fe ...  

Science Conference Proceedings (OSTI)

To improve magnesium's hydrogen absorption properties, palladium was ball milled ... hydrogen in three disproportional reactions; Mg6Pd + 2.35H2 + energy ... In-situ Chemistry Mapping of Hydrogen Storage Materials by Neutron Diffraction.

73

Development of membranes for hydrogen separation: Pd-coated V-10Pd  

DOE Green Energy (OSTI)

Numerous Group IVB and VB alloys were prepared and tested as potential membrane materials but most of these materials were brittle or exhibited cracking during hydrogen exposure. One of the more ductile alloys, V-10Pd (at. %), was fabricated into a thin (107-{micro}m thick) composite membrane coated with 100 nm of Pd on each side. The material was tested for hydrogen permeability, resistance to hydrogen embrittlement, and long term hydrogen flux stability. The hydrogen permeability, {phi}, of the V-10Pd membrane was 3.86 x 10{sup -8} mol H{sub 2} m{sup -1} s{sup -1} Pa{sup -0.5} (avg. of three different samples) at 400 C, which is slightly higher than the permeability of Pd-23Ag at that temperature. A 1400 h hydrogen flux test at 400 C demonstrated that the rate of metallic interdiffusion was slow between the V-10Pd foil and the 100-nm-thick Pd coating on the surface. However, at the end of testing the membrane cracked at 118 C because of hydrogen embrittlement.

Paglieri, Stephen N [Los Alamos National Laboratory; Wermer, Joseph R [Los Alamos National Laboratory; Buxbaum, Robert E [REB RESEARCH AND CONSULTING; Ciocco, Michael V [NETL; Howard, Bret H [NETL; Morreale, Bryan D [NETL

2009-01-01T23:59:59.000Z

74

Ca{sub 2}Pd{sub 3}Ge, a new fully ordered ternary Laves phase structure  

SciTech Connect

The title compound, Ca{sub 2}Pd{sub 3}Ge, was prepared as a part of a systematic investigation of the Ca-Pd-Ge ternary phase diagram. The structure was determined and refined from single-crystal X-ray diffraction data. It is a new fully ordered ternary Laves phase with the space group R-3m, Z=3, a=5.6191 (5) A, c=12.1674 (7) A, wR{sub 2}=0.054 (all data) and is isostructural to Mg{sub 2}Ni{sub 3}Si (Noreus et al., 1985 [17]) but due to the larger size of all elements in Ca{sub 2}Pd{sub 3}Ge, the cell axes are approximately 10% longer. The compound may formally be considered as a Zintl compound, with [Pd{sub 3}Ge]{sup 4-} forming a poly-anionic network and divalent Ca cations located in truncated tetrahedral interstices. The electronic structure and chemical bonding of Ca{sub 2}Pd{sub 3}Ge is discussed in terms of LMTO band structure calculations and compared with CaPd{sub 2} (MgCu{sub 2}-type). - Graphical abstract: The title compound, Ca{sub 2}Pd{sub 3}Ge is a new fully ordered ternary Laves phase which may formally be considered as a Zintl compound, with [Pd{sub 3}Ge]{sup 4-} forming a poly-anionic network and divalent Ca cations located in truncated tetrahedral interstices. The structure is composed of Kagome net layers, consisting of Pd atoms only, which are stacked in an ABC sequence. Band structure calculations show that the Fermi level is located at a local minimum of the DOS (pseudo-gap) indicating that the charge is roughly optimized in the structure. Highlights: Black-Right-Pointing-Pointer Site specific segregation in a Laves phase that is also a Zintl phase. Black-Right-Pointing-Pointer Pseudo-gap at the Fermi level in a Laves phase. Black-Right-Pointing-Pointer Distorted Frank-Kasper polyhedron.

Doverbratt, Isa, E-mail: isa.doverbratt@polymat.lth.se [Centre for Analysis and Synthesis, Lund University, P.O. Box 124, 22100 Lund (Sweden); Ponou, Simeon; Lidin, Sven [Centre for Analysis and Synthesis, Lund University, P.O. Box 124, 22100 Lund (Sweden)

2013-01-15T23:59:59.000Z

75

Fabrication of Pd/Pd-Alloy Films by Surfactant Induced Electroless Plating for Hydrogen Separation from Advanced Coal Gasification Processes  

SciTech Connect

Dense Pd, Pd-Cu and Pd-Ag composite membranes on microporous stainless steel substrate (MPSS) were fabricated by a novel electroless plating (EP) process. In the conventional Pd-EP process, the oxidation-reduction reactions between Pd-complex and hydrazine result in an evolution of NH{sub 3} and N{sub 2} gas bubbles. When adhered to the substrate surface and in the pores, these gas bubbles hinder uniform Pd-film deposition which results in dendrite growth leading to poor film formation. This problem was addressed by introducing cationic surfactant in the electroless plating process known as surfactant induced electroless plating (SIEP). The unique features of this innovation provide control of Pd-deposition rate, and Pd-grain size distribution. The surfactant molecules play an important role in the EP process by tailoring grain size and the process of agglomeration by removing tiny gas bubbles through adsorption at the gas-liquid interface. As a result surfactant can tailor a nanocrystalline Pd, Cu and Ag deposition in the film resulting in reduced membrane film thickness. Also, it produces a uniform, agglomerated film structure. The Pd-Cu and Pd-Ag membranes on MPSS support were fabricated by sequential deposition using SIEP method. The pre- and post-annealing characterizations of these membranes (Pd, Pd-Cu and Pd-Ag on MPSS substrate) were carried out by SEM, EDX, XRD, and AFM studies. The SEM images show significant improvement of the membrane surface morphology, in terms of metal grain structures and grain agglomeration compared to the membranes fabricated by conventional EP process. The SEM images and helium gas-tightness studies indicate that dense and thinner films of Pd, Pd-Cu and Pd-Ag membranes can be produced with shorter deposition time using surfactant. H{sub 2} Flux through the membranes fabricated by SIEP shows large improvement compared to those by CEP with comparable permselectivity. Pd-MPSS composite membrane was subjected to test for long term performance and thermal cycling (573 - 723 - 573 K) at 15 psi pressure drop for 1200 hours. Pd membranes showed excellent hydrogen permeability and thermal stability during the operational period. Under thermal cycling (573 K - 873 K - 573 K), Pd-Cu-MPSS membrane was stable and retained hydrogen permeation characteristics for over three months of operation. From this limited study, we conclude that SIEP is viable method for fabrication of defect-free, robust Pd-alloy membranes for high-temperature H{sub 2}-separation applications.

Ilias, Shamsuddin; Kumar, Dhananjay

2012-07-31T23:59:59.000Z

76

Highly Active Pt(3)Pb and Core-Shell Pt(3)Pb-Pt Electrocatalysts for Formic Acid Oxidation  

DOE Green Energy (OSTI)

Formic acid is a promising chemical fuel for fuel cell applications. However, due to the dominance of the indirect reaction pathway and strong poisoning effects, the development of direct formic acid fuel cells has been impeded by the low activity of existing electrocatalysts at desirable operating voltage. We report the first synthesis of Pt{sub 3}Pb nanocrystals through solution phase synthesis and show they are highly efficient formic acid oxidation electrocatalysts. The activity can be further improved by manipulating the Pt{sub 3}Pb-Pt core-shell structure. Combined experimental and theoretical studies suggest that the high activity from Pt{sub 3}Pb and the Pt-Pb core-shell nanocrystals results from the elimination of CO poisoning and decreased barriers for the dehydrogenation steps. Therefore, the Pt{sub 3}Pb and Pt-Pb core-shell nanocrystals can improve the performance of direct formic acid fuel cells at desired operating voltage to enable their practical application.

Kang Y.; Stach E.; Qi L.; Li M.; Diaz R.E.; Su D.; Adzic R.R.; Li J.; Murray C.B.

2012-03-27T23:59:59.000Z

77

PT1_US.xls  

Gasoline and Diesel Fuel Update (EIA)

PT1. Energy Production Estimates in Physical Units, United States, 1960 - 2011 PT1. Energy Production Estimates in Physical Units, United States, 1960 - 2011 1960 436,425 12,771,038 2,574,933 NA 1961 422,535 13,254,025 2,621,758 NA 1962 441,072 13,876,622 2,676,189 NA 1963 479,356 14,746,663 2,752,723 NA 1964 506,453 15,546,592 2,786,822 NA 1965 529,355 16,039,753 2,848,514 NA 1966 549,065 17,206,628 3,027,763 NA 1967 567,031 18,171,325 3,215,742 NA 1968 558,995 19,322,400 3,329,042 NA 1969 573,226 20,698,240 3,371,751 NA 1970 614,969 21,920,642 3,517,450 NA 1971 563,122 22,493,012 3,453,914 NA 1972 602,491 22,531,698 3,455,368 NA 1973 598,569 22,647,549 3,360,903 NA 1974 610,021 21,600,522 3,202,585 NA 1975 654,641 20,108,661 3,056,779 NA 1976 684,914 19,952,438 2,976,180 NA 1977 697,205 20,025,463 3,009,265 NA 1978 670,164 19,974,033 3,178,216 NA 1979 781,135 20,471,260 3,121,310 NA 1980 829,747 20,179,724 3,146,365 NA

78

Au-Pt heteroaggregate dendritic nanostructures and Au-Pt alloy nanoparticles and their use as catalysts  

DOE Patents (OSTI)

Au--Pt heteroaggregate dendritic nanostructures and AuPt alloy nanoparticles, and their use as anodic catalysts in fuel cells.

Eichhorn, Bryan W. (University Park, MD); Zhou, Shenghu (Greenbelt, MD); Jackson, Gregory Scott (University Park, MD)

2011-10-18T23:59:59.000Z

79

Interaction of CO with Surface PdZn Alloys  

SciTech Connect

The adsorption and bonding configuration of CO on clean and Zn-covered Pd(111) surfaces was studied using Low Energy Electron Diffraction (LEED), Temperature Programmed Desorption (TPD) and High Resolution Electron Energy Loss Spectroscopy (HREELS). LEED and TPD results indicate that annealing at 520 K is sufficient to induce reaction between adsorbed Zn atoms and the Pd(111) surface resulting in the formation of an ordered surface PdZn alloy. Carbon monoxide was found to bond more weakly to the Zn/Pd(111) alloy surfaces compared to clean Pd(111). Zn addition was also found to alter the preferred adsorption sites for CO from threefold hollow to atop sites. Similar behavior was observed for supported Pd-Zn/Al2O3 catalysts. The results of this study show that both ensemble and electronic effects play a role in how Zn alters the interactions of CO with the surface.

Jeroro, E.; Lebarbier, Vanessa MC; Datye, Abhaya; Wang, Yong; Vohs, John M.

2007-12-01T23:59:59.000Z

80

Bismuth as a modifier of Au Pd catalyst: Enhancing selectivity in alcohol oxidation by suppressing parallel reaction  

SciTech Connect

Bi has been widely employed as a modifier for Pd and Pt based catalyst mainly in order to improve selectivity. We found that when Bi was added to the bimetallic system AuPd, the effect on activity in alcohol oxidation mainly depends on the amount of Bi regardless its position, being negligible when Bi was 0.1 wt% and detectably negative when the amount was increased to 3 wt%. However, the selectivity of the reactions notably varied only when Bi was deposited on the surface of metal nanoparticles suppressing parallel reaction in both benzyl alcohol and glycerol oxidation. After a careful characterization of all the catalysts and additional catalytic tests, we concluded that the Bi influence on the activity of the catalysts could be ascribed to electronic effect whereas the one on selectivity mainly to a geometric modification. Moreover, the Bi-modified AuPd/AC catalyst showed possible application in the production of tartronic acid, a useful intermediate, from glycerol.

Villa, Alberto [Universita di Milano, Italy; Wang, Di [Fritz Haber Institute of the Max Planck Society, Berlin, Germany; Veith, Gabriel M [ORNL; Prati, Laura [Universita di Milano, Italy

2012-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "ni pd pt" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Current-Voltage and Capacitance-Voltage characteristics of Pd ...  

Science Conference Proceedings (OSTI)

Presentation Title, Current-Voltage and Capacitance-Voltage characteristics of Pd ... Nonlocal Modeling in High Rate Deformation and Ductile Fracture of ...

82

Ternary CuPdM Alloys for Hydrogen Separation Membranes  

Science Conference Proceedings (OSTI)

Pd-Based Membrane Reactor for Simultaneous CO2 Sequestration and Hydrogen Production from Syngas Produced from IGCC · Search and Study of a Solid ...

83

Synthesis of Au-Pd Nanoflowers Through Nanocluster Assembly  

SciTech Connect

Reduction of Pd ions by hydroquinone in the presence of gold nanoparticles and polyvinylpyrrolidone resulted in the formation of nanoflowers with a Au core and Pd petals. Addition of HCl to the synthesis halted the reduction by hydroquinone and enabled the acquisition of snapshots of the nanoflowers at different stages of growth. TEM images of the reaction after 10 s show that the nanoflower morphology resulted from the homogeneous nucleation of Pd clusters in solution and their subsequent attachment to gold seeds coated with a thin (0.8 {+-} 0.1 nm) shell of Pd. UV-visible spectra also indicate Pd clusters formed in the early stages of the reaction and disappeared as the nanoflowers grew. The speed at which this reaction can be halted is useful not only for producing a variety of bimetallic nanostructures with precisely controlled dimensions and morphologies but also for understanding the growth mechanism of these structures. The ability of the AuPd core-shell structure to catalyze the Suzuki coupling reaction of iodobenzene to phenylboronic acid was probed and compared against the activity of Pd nanocubes and thin-shelled AuPd core-shell nanoparticles. The results of this study suggest that Suzuki coupling was not affected by the surface structure or subsurface composition of the nanoparticles, but instead was primarily catalyzed by molecular Pd species that leached from the nanostructures.

Xu, Jianguang [Duke University; Howe, Jane Y [ORNL; Chi, Miaofang [ORNL; Wilson, Adria [Duke University; Rathmall, Aaron [Duke University; Wiley, Benjamin J [ORNL

2011-01-01T23:59:59.000Z

84

PT2_US.xls  

Gasoline and Diesel Fuel Update (EIA)

PT2. Energy Production Estimates in Trillion Btu, United States, 1960 - 2011 PT2. Energy Production Estimates in Trillion Btu, United States, 1960 - 2011 1960 10,590 14,119 14,935 6 NA 2,928 2,928 42,578 1961 10,239 14,642 15,206 20 NA 2,952 2,952 43,060 1962 10,671 15,322 15,522 26 NA 3,117 3,117 44,658 1963 11,605 16,270 15,966 38 NA 3,096 3,096 46,976 1964 12,274 17,152 16,164 40 NA 3,225 3,225 48,854 1965 12,832 17,691 16,521 43 NA 3,396 3,396 50,483 1966 13,281 18,967 17,561 64 NA 3,432 3,432 53,305 1967 13,697 20,019 18,651 88 NA 3,690 3,690 56,146 1968 13,487 21,276 19,308 142 NA 3,773 3,773 57,986 1969 13,833 22,764 19,556 154 NA 4,095 4,095 60,402 1970 14,877 24,098 20,401 239 NA 4,070 4,070 63,686 1971 13,518 24,747 20,033 413 NA 4,262 4,262 62,972 1972 14,392 24,819 20,041 584 NA 4,382 4,382 64,218 1973 14,006 24,873 19,493 910 NA 4,411 4,411 63,694 1974 14,025 23,723 18,575 1,272 NA 4,742 4,742 62,336 1975 14,982 22,098 17,729 1,900 NA 4,687 4,687

85

Department of Energy Pt. 824, App. A  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Sfmt 8002 Y:SGML223033.XXX 223033 jdjones on DSK8KYBLC1PROD with CFR 529 Department of Energy Pt. 824, App. A penalties will also take into account the gravity, circumstances,...

86

Reactivity and stability of platinum and platinum alloy catalysts toward the oxygen reduction reaction  

E-Print Network (OSTI)

Density functional theory (DFT) is used to study the reactivity of Pt and Pt-M (M: Pd, Co, Ni, V, and Rh) alloy catalysts towards the oxygen reduction reaction (ORR) as a function of the alloy overall composition and surface atomic distribution and compared to that on pure Pt surfaces. Reactivity is evaluated on the basis of the adsorption strength of oxygenated compounds which are intermediate species of the four-electron oxygen reduction reaction, separating the effect of the first electron-proton transfer from that of the three last electron-proton transfer steps. It is found that most homogeneous distribution PtxM catalysts thermodynamically favor the dissociation of adsorbed OOH in comparison with pure Platinum and adsorb strongly O and OH due to the strong oxyphilicity of the M elements. On the other hand, in all cases skin Platinum surfaces catalysts do not favor the dissociation of adsorbed OOH and do favor the reduction of M-O and M-OH with respect to Platinum. Considering the overall pathway of the reactions to catalyze the ORR most of the skin Platinum monolayer catalysts provide more negative free energy changes and should behave at least in a similar way than Platinum in following order: Pt3V (skin Pt) > Pt3Co (skin Pt) > Pt3Ni (skin Pt) > Pt > PtPd (skin) > Pt4Rh (skin Pt) > PtPd3 (skin ). In all cases, the reactivity is shown to be not only sensitive to the overall composition of the catalyst, but most importantly to the surface atomic distribution. Proposed electrochemical dissolution reactions of the catalyst atoms are also analyzed for the ORR catalysts, by computing the free energy changes of Platinum and bimetallic Pt-X (X: Co, Pd, Ni, and Rh) catalysts. It is found that Platinum is thermodynamically more stable than Pt-alloys in Pt3Co, Pt3Pd, Pt3Ni and Pt4Rh.

Calvo, Sergio Rafael

2007-12-01T23:59:59.000Z

87

Mechanical Properties of High Strength NiTiHfPd Shape Memory ...  

Science Conference Proceedings (OSTI)

About this Abstract. Meeting, Materials Science & Technology 2011. Symposium, Shape Memory Alloys. Presentation Title, Mechanical Properties of High ...

88

Biosupported Bimetallic Pd Au Nanocatalysts for Dechlorination of Environmental Contaminants  

SciTech Connect

Biologically produced monometallic palladium nanoparticles (bio-Pd) have been shown to catalyze the dehalogenation of environmental contaminants, but fail to efficiently catalyze the degradation of other important recalcitrant halogenated compounds. This study represents the first report of biologically produced bimetallic Pd/Au nanoparticle catalysts. The obtained catalysts were tested for the dechlorination of diclofenac and trichloroethylene. When aqueous bivalent Pd(II) and trivalent Au(III) ions were both added to concentrations of 50 mg L{sup -1} and reduced simultaneously by Shewanella oneidensis in the presence of H{sub 2}, the resulting cell-associated bimetallic nanoparticles (bio-Pd/Au) were able to dehalogenate 78% of the initially added diclofenac after 24 h; in comparison, no dehalogenation was observed using monometallic bio-Pd or bio-Au. Other catalyst-synthesis strategies did not show improved dehalogenation of TCE and diclofenac compared with bio-Pd. Synchrotron-based X-ray diffraction, (scanning) transmission electron microscopy and energy dispersive X-ray spectroscopy indicated that the simultaneous reduction of Pd and Au supported on cells of S. oneidensis resulted in the formation of a unique bimetallic crystalline structure. This study demonstrates that the catalytic activity and functionality of possibly environmentally more benign biosupported Pd-catalysts can be improved by coprecipitation with Au.

De Corte, S.; Fitts, J.; Hennebel, T.; Sabbe, T.; Bliznuk, V.; Verschuere, S.; van der Lelie, D.; Verstraete, W.; Boon, N.

2011-08-30T23:59:59.000Z

89

Catalytic studies of supported Pd-Au catalysts  

E-Print Network (OSTI)

Although Pd-Au high-surface area catalysts are used in industry to improve activity and selectivity, a thorough understanding of the nature of these enhancements is lacking. A molecular-level understanding of catalytic reactions under actual reaction conditions is the ultimate goal. This thesis is mainly focused on the application of Pd-Au supported catalysts for vinyl acetate synthesis and CO oxidation reactions using highsurface area catalysts. We have attempted to improve the conventional Pd-Au based catalyst by synthesizing novel acetate-based and polymer-based catalysts. The corresponding catalytic reactivity and selectivity were measured and compared to conventional Pd-Au based catalyst systems. Subsequent characterization was performed using characterization techniques, such as, X-ray diffraction (XRD) and transmission electron microscopy (TEM). From our bimetallic catalytic studies, it was evident that the addition of Au to Pd leads to increased reactivity and selectivity. This surface modification is an important factor in the altered reaction kinetics for vinyl acetate (VA) synthesis and CO oxidation reactions. Promoted and unpromoted Pd-Au/SiO2/K+ catalyst were used for VA synthesis and the effect of pre-adsorbed O2, acetic acid and the role of oxygen were explored. The VA reaction rate of novel acetate-based Pd-Au/SiO2 catalyst was 3.5 times higher than conventional Pd-Au catalysts. Also, 100% selectivity was obtained for acetate-based Pd-Au/SiO2 at 130 oC and the VA formation rate was comparable to that of conventional Pd-Au catalysts. Therefore, the acetate-based Pd-Au/SiO2 catalyst seems very promising and can be explored further. Also, Pd(1):Au(4)/SiO2 catalysts demonstrate 100% CO conversion at much lower temperatures (90 oC) compared with other Pd-Au based catalysts. Furthermore, we were successful in obtaining sufficient CO oxidation activity with increased metal loading (5 wt%) and these catalysts did not deactivate under above-ambient reaction temperature conditions, which make 1:4 Pd- Au/SiO2 catalyst a good candidate for further exploration in CO oxidation reactions.

Boopalachandran, Praveenkumar

90

Carbon-Supported IrNi Core-Shell Nanoparticles: Synthesis Characterization and Catalytic Activity  

Science Conference Proceedings (OSTI)

We synthesized carbon-supported IrNi core-shell nanoparticles by chemical reduction and subsequent thermal annealing in H{sub 2}, and verified the formation of Ir shells on IrNi solid solution alloy cores by various experimental methods. The EXAFS analysis is consistent with the model wherein the IrNi nanoparticles are composed of two-layer Ir shells and IrNi alloy cores. In situ XAS revealed that the Ir shells completely protect Ni atoms in the cores from oxidation or dissolution in an acid electrolyte under elevated potentials. The formation of Ir shell during annealing due to thermal segregation is monitored by time-resolved synchrotron XRD measurements, coupled with Rietveld refinement analyses. The H{sub 2} oxidation activity of the IrNi nanoparticles was found to be higher than that of a commercial Pt/C catalyst. This is predominantly due to Ni-core-induced Ir shell contraction that makes the surface less reactive for IrOH formation, and the resulting more metallic Ir surface becomes more active for H{sub 2} oxidation. This new class of core-shell nanoparticles appears promising for application as hydrogen anode fuel cell electrocatalysts.

K Sasaki; K Kuttiyiel; L Barrio; D Su; A Frenkel; N Marinkovic; D Mahajan; R Adzic

2011-12-31T23:59:59.000Z

91

Pd/k for RTF and 232-H TCAP units  

DOE Green Energy (OSTI)

The Thermal Cycling Absorption Process (TCAP) will be used in the Replacement Tritium Facility (RTF) and 232-H Tritium Facility for separation of hydrogen isotopes. These TCAP units will be filled with palladium deposited on kieselguhr (Pd/k) that has been heat treated to reduce particle breakdown and sieved to remove particles smaller than 50 mesh (300{mu}m). Pd/k ordered for several applications in the RTF, including TCAP, was received at SRL in April 1989. Shortly thereafter, flow restriction caused by breakdown of the Pd/k particles was detected during operation of a TCAP unit in the Advanced Hydride Laboratory (AHL). Subsequent research at SRL showed that heating Pd/k at 1100{degrees}C in air for 2 hours greatly reduces mechanical breakdown. Based on these favorable results, sufficient Pd/k was heat treated to fill RTF and Building 232-H TCAP units. 11 refs., 11 figs., 7 tabs.

Mosley, W.C.

1991-01-29T23:59:59.000Z

92

CX-009904: Categorical Exclusion Determination | Department of...  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

using high surface area nitrogen doped titania nanotube arrays, sensitized with nano-dimensional islands of co-catalysts copper and Ni, Pd or Pt. CX-009904.pdf More...

93

CNST NanoFab Equipment - Dry Etch  

Science Conference Proceedings (OSTI)

... Features: Milling of metals (such as Au, Co, Cu, Fe, Ir, Mn, Ni, Permalloy, Pd, Pt ... SIMS can detect the composition of ion mill by-products for up to four ...

2013-04-05T23:59:59.000Z

94

Metrology and Precision for Nanoscale Manufacturing:  

Science Conference Proceedings (OSTI)

... 27 cobalt Co 78 platinum Pt 45 palladium Pd 28 nickel Ni 35 Br35 Bromine Br 30 zinc Zn 32 germanium Ge 83 bismuth Bi 6 carbon C 2 helium He ...

95

Neutral bimetallic transition metal phenoxyiminato catalysts and related polymerization methods  

SciTech Connect

A catalyst composition comprising a neutral bimetallic diphenoxydiiminate complex of group 10 metals or Ni, Pd or Pt is disclosed. The compositions can be used for the preparation of homo- and co-polymers of olefinic monomer compounds.

Marks, Tobin J. (Evanston, IL); Rodriguez, Brandon A. (Evanston, IL); Delferro, Massimiliano (Chicago, IL)

2012-08-07T23:59:59.000Z

96

Hydrogen catalysis and scavenging action of Pd-POSS nanoparticles  

DOE Green Energy (OSTI)

Prompted by the need for a self-supported, chemically stable, and functionally flexible catalytic nanoparticle system, we explore a system involving Pd clusters coated with a monolayer of polyhedral oligomeric silsesquioxane (POSS) cages. With an initial theoretical focus on hydrogen catalysis and sequestration in the Pd-POSS system, we report Density Functional Theory (DFT) results on POSS binding energies to the Pd(110) surface, hydrogen storing ability of POSS, and possible pathways of hydrogen radicals from the catalyst surface to unsaturated bonds away from the surface.

Maiti, A; Gee, R H; Maxwell, R; Saab, A

2007-02-01T23:59:59.000Z

97

Electrical current suppression in Pd-doped vanadium pentoxide nanowires caused by reduction in PdO due to hydrogen exposure  

SciTech Connect

Pd nanoparticle-doped vanadium pentoxide nanowires (Pd-VONs) were synthesized. Electrical current suppression was observed when the Pd-VON was exposed to hydrogen gas, which cannot be explained by the work function changes mentioned in previous report such as Pd-doped carbon nanotubes and SnO{sub 2} nanowires. Using the x-ray photoelectron spectroscopy, we found that the reduction in PdO due to hydrogen exposure plays an important role in the current suppression of the Pd-VON.

Kim, Byung Hoon; Oh, Soon-Young; Yu, Han Young; Yun, Yong Ju; Kim, Yark Yeon; Hong, Won G. [Electronics and Telecommunications Research Institute (ETRI), Daejeon 305-700 (Korea, Republic of); Jeong, Hu Young; Lee, Jeong Yong [Department of Materials Science and Engineering, KAIST, Daejeon 305-701 (Korea, Republic of); Kim, Hae Jin [Korea Basic Science Institute, Daejeon 305-333 (Korea, Republic of)

2010-04-19T23:59:59.000Z

98

Decomposition of Furan on Pd(111)  

SciTech Connect

Periodic density functional theory calculations (GGA-PBE) have been performed to investigate the mechanism for the decomposition of furan up to CO formation on the Pd(111) surface. At 1/9 ML coverage, furan adsorbs with its molecular plane parallel to the surface in several states with nearly identical adsorption energies of -1.0 eV. The decomposition of furan begins with the opening of the ring at the C-O position with an activation barrier of E{sub a} = 0.82 eV, which yields a C{sub 4}H{sub 4}O aldehyde species that rapidly loses the {alpha} H to form C{sub 4}H{sub 3}O (E{sub a} = 0.40 eV). C{sub 4}H{sub 3}O further dehydrogenates at the {delta} position to form C{sub 4}H{sub 2}O (E{sub a} = 0.83 eV), before the {alpha}-{beta} C-C bond dissociates (E{sub a} = 1.08 eV) to form CO. Each step is the lowest-barrier dissociation step in the respective species. A simple kinetic analysis suggests that furan decomposition begins at 240-270 K and is mostly complete by 320 K, in close agreement with previous experiments. It is suggested that the C{sub 4}H{sub 2}O intermediate delays the decarbonylation step up to 350 K.

Xu, Ye [ORNL

2012-01-01T23:59:59.000Z

99

Composite Pd and Pd Alloy Porous Stainless Steel Membranes for Hydrogen Production and Process Intensification  

DOE Green Energy (OSTI)

The synthesis of composite Pd membranes has been modified by the addition of a Al(OH){sub 3} graded layer and sequential annealing at high temperatures to obtain membranes with high permeance and outstanding selectivity stability for over 4000 hours at 450°C. Most of the membranes achieved in this work showed H{sub 2} flux well above 2010 DOE targets and in some case, also above 2015 DOE targets. Similar composite membranes were tested in water gas shift reaction atmospheres and showed to be stable with high CO conversion and high hydrogen recovery for over 1000 hours. The H{sub 2} permeance of composite Pd-Au membranes was studied as well as its resistance in H{sub 2}S containing atmospheres. H{sub 2}S poisoning of Pd-based membranes was reduced by the addition of Au and the loss undergone by membranes was found to be almost totally recoverable with 10-30 wt%Au. PSA technique was studied to test the possibility of H{sub 2}S and COS removal from feed stream with limited success since the removal of H{sub 2}S also led to the removal of a large fraction of the CO{sub 2}. The economics of a WGS bundle reactor, using the information of the membranes fabricated under this project and integrated into an IGCC plant were studied based on a 2D reactor modeling. The calculations showed that without a government incentive to impose a CO{sub 2} tax, application of WGS membrane reactors in IGCC would be not as economically attractive as regular pulverized coal plants.

Yi Hua Ma; Nikolaos Kazantzis; Ivan Mardilovich; Federico Guazzone; Alexander Augustine; Reyyan Koc

2011-11-06T23:59:59.000Z

100

Cluster expansion of fcc Pd-V intermetallics  

Science Conference Proceedings (OSTI)

A cluster expansion is used to compute fcc ground states from first principles for the Pd-V system. Intermetallic structures are not assumed but derived rigorously by minimizing the configurational energy subject to linear constraints. A large number of concentration-independent interactions are calculated by the method of direct configurational averaging. Agreement with the fcc-based portion of the experimentally-determined Pd-V phase diagram is quite satisfactory. 25 refs., 2 figs.

de Fontaine, D.; Wolverton, C.; Ceder, G. (Lawrence Berkeley Lab., CA (United States)); Dreysse, H. (Nancy-1 Univ., 54 (France). Lab. de Physique du Solide)

1991-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "ni pd pt" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Ni-Zr (Nickel - Zirconium)  

Science Conference Proceedings (OSTI)

Ni-Zr crystallographic data...99.9 to 100 hP 2 P 6 3 / mmc (a) Triclinic. (b) Stoichiometric. (c) Zr-rich...

102

Imaging Chemical Aggregation of Ni/NiO Particles from Reduced NiO-YSZ  

SciTech Connect

Energy dispersive X-ray spectroscopy (EDS) mapping of nickel oxide yttria-stabilized zirconia (NiO-YSZ) was carried out after various hydrogen reducing and methane steam reforming conditions. Nickel aggregation was visualized after methane steam reforming by correlating Ni K{sub {alpha}} map with scanning transmission electron microscopy (STEM) images. From the reduced O K{sub {alpha}} intensities in the Ni K{sub {alpha}} dominated regions after methane steam reforming, NiO reduction in to Ni can be interpreted. From correlation between Zr K{sub {alpha}} and O K{sub {alpha}} maps, high stability of YSZ was also realized. Examples of NiO-YSZ overlapped particles are considered to discuss chemical imaging of a single particle.

Saraf, Laxmikant V.

2011-07-20T23:59:59.000Z

103

Oxygen Reduction Reaction on Dispersed and Core-Shell Metal Alloy Catalysts: Density Functional Theory Studies  

E-Print Network (OSTI)

Pt-based alloy surfaces are used to catalyze the electrochemical oxygen reduction reaction (ORR), where molecular oxygen is converted into water on fuel cell electrodes. In this work, we address challenges due to the cost of high Pt loadings in the cathode electrocatalyst, as well as those arising from catalyst durability. We aim to develop an increased understanding of the factors that determine ORR activity together with stability against surface segregation and dissolution of Pt-based alloys. We firstly focus on the problem of determining surface atomic distribution resulting from surface segregation phenomena. We use first-principles density functional theory (DFT) calculations on PtCo and Pt3Co overall compositions, as well as adsorption of water and atomic oxygen on PtCo(111) and Pt-skin structures. The bonding between water and surfaces of PtCo and Pt-skin monolayers are investigated in terms of orbital population. Also, on both surfaces, the surface reconstruction effect due to high oxygen coverage and water co-adsorption is investigated. Although the PtCo structures show good activity, a large dissolution of Co atoms tends to occur in acid medium. To tackle this problem, we examine core-shell structures which showed improved stability and activity compared to Pt(111), in particular, one consisting of a surface Pt-skin monolayer over an IrCo or Ir3Co core, with or without a Pd interlayer between the Pt surface and the Ir-Co core. DFT analysis of surface segregation, surface stability against dissolution, surface Pourbaix diagrams, and reaction mechanisms provide useful predictions on catalyst durability, onset potential for water oxidation, surface atomic distribution, coverage of oxygenated species, and activity. The roles of the Pd interlayer in the core-shell structures that influence higher ORR activity are clarified. Furthermore, the stability and activity enhancement of new shell-anchor-core structures of Pt/Fe-C/core, Pt/Co-C/core and Pt/Ni-C/core are demonstrated with core materials of Ir, Pd3Co, Ir3Co, IrCo and IrNi. Based on the analysis, Pt/Fe-C/Ir, Pt/Co-C/Ir, Pt/Ni-C/Ir, Pt/Co-C/Pd3Co, Pt/Fe-C/Pd3Co, Pt/Co- C/Ir3Co, Pt/Fe-C/Ir3Co, Pt/Co-C/IrCo, Pt/Co-C/IrNi, and Pt/Fe-C/IrNi structures show promise in terms of both improved durability and relatively high ORR activity.

Hirunsit, Pussana

2010-08-01T23:59:59.000Z

104

MgO buffer layers on rolled nickel or copper as superconductor substrates  

SciTech Connect

Buffer layer architectures are epitaxially deposited on biaxially-textured rolled-Ni and/or Cu substrates for high current conductors, and more particularly buffer layer architectures such as MgO/Ag/Pt/Ni, MgO/Ag/Pd/Ni, MgO/Ag/Ni, MgO/Ag/Pd/Cu, MgO/Ag/Pt/Cu, and MgO/Ag/Cu. Techniques used to deposit these buffer layers include electron beam evaporation, thermal evaporation, rf magnetron sputtering, pulsed laser deposition, metal-organic chemical vapor deposition (MOCVD), combustion CVD, and spray pyrolysis.

Paranthaman, Mariappan (Knoxville, TN); Goyal, Amit (Knoxville, TN); Kroeger, Donald M. (Knoxville, TN); List, III, Frederic A. (Andersonville, TN)

2001-01-01T23:59:59.000Z

105

Method for making MgO buffer layers on rolled nickel or copper as superconductor substrates  

SciTech Connect

Buffer layer architectures are epitaxially deposited on biaxially-textured rolled-Ni and/or Cu substrates for high current conductors, and more particularly buffer layer architectures such as MgO/Ag/Pt/Ni, MgO/Ag/Pd/Ni, MgO/Ag/Ni, MgO/Ag/Pd/Cu, MgO/Ag/Pt/Cu, and MgO/Ag/Cu. Techniques used to deposit these buffer layers include electron beam evaporation, thermal evaporation, rf magnetron sputtering, pulsed laser deposition, metal-organic chemical vapor deposition (MOCVD), combustion CVD, and spray pyrolysis.

Paranthaman, Mariappan (Knoxville, TN); Goyal, Amit (Knoxville, TN); Kroeger, Donald M. (Knoxville, TN); List, III, Frederic A. (Andersonville, TN)

2002-01-01T23:59:59.000Z

106

Reactivity of hydrogen with uranium in the presence of Pt  

DOE Green Energy (OSTI)

The surface-reaction of di-hydrogen with uranium in the presence of Pt clusters has been studied using scanning tunneling microscopy (STM). Uranium was deposited on highly oriented pyrolytic graphite (HOPG) and annealed at temperatures up to 1200{degrees}C to obtain atomically pyrolytic flat surfaces. Pt clusters were then formed using evaporation from a Pt source onto the surface and subsequent annealing. Hydrogen mainly attacked uranium in the vicinity of Pt clusters and formed hydride. The hydride formation probability is almost constant at 2.3x10{sup -4} over the range of exposures studied.

Balooch, M.; Siekhaus, W.J.

1997-07-01T23:59:59.000Z

107

Controlling Composition at the Individual FePt Nanoparticle Level  

Science Conference Proceedings (OSTI)

CNT Based Thermoelectric Devices for Energy Harvesting · Controlling Composition at the Individual FePt Nanoparticle Level · Corrosion Rates and Mechanical ...

108

Comparative and Functional Genomics of Rhodococcus opacus PD630 for Biofuels Development  

E-Print Network (OSTI)

Comparative and Functional Genomics of Rhodococcus opacus PD630 for Biofuels Development Jason W and Functional Genomics of Rhodococcus opacus PD630 for Biofuels Development. PLoS Genet 7(9): e1002219. doi:10

Sinskey, Anthony J.

109

Development and Applications of Pd Catalysts for C-N Cross-Coupling Reactions  

E-Print Network (OSTI)

Chapter 1 A procedure for forming a highly active Pd(0) catalyst from Pd(OAc) 2, water, and biarylphosphine ligands has been developed. This protocol generates a catalyst system, which exhibits excellent reactivity and ...

Fors, Brett P

2011-01-01T23:59:59.000Z

110

Hydrogen Absorption in Pd-based Nanostructures - Final Report  

DOE Green Energy (OSTI)

Pd is known to absorb hydrogen. Molecules are normally chemisorbed at the surface in a process where the molecule breaks into two hydrogen atoms, and the protons are then absorbed into the bulk. This process consists of electron filling holes in the Pd 4d band near the Fermi energy, which due to the high density of states at the Fermi energy, is an energetically favorable process. Our aim with this project was to determine possible changes in magnetic properties with Pd nm-length-scale thick layers intercalated by magnetic materials. Before the start of this work, the literature indicated that there were several possible scenarios by which this could happen: i) the Pd will be magnetized due to a proximity effect with nearby magnetic layers, resulting in changes in the magnetization due to H2 absorption; ii) some H will be absorbed into the magnetic layers, causing a change in the magnetic exchange interactions; or iii) absorption of H2 will cause an expansion of the lattice, resulting in a magnetoelastic effect which changes the magnetic properties.

David Lederman

2012-10-22T23:59:59.000Z

111

Ethylene combustion on unsupported and supported Pd: a comparative , Y.-F. Hana,b  

E-Print Network (OSTI)

Ethylene combustion on unsupported and supported Pd: a comparative study D. Kumara , Y.-F. Hana Ethylene combustion is studied at elevated pressures on Pd(100) and compared with supported Pd catalysts with increasing O2 pressure. The combustion kinetics is related to the corresponding surface carbon coverage

Goodman, Wayne

112

Influence of nuclear structure on sub-barrier hindrance in Ni+Ni fusion  

E-Print Network (OSTI)

Fusion-evaporation cross sections for $^{64}$Ni+$^{64}$Ni have been measured down to the 10 nb level. For fusion between two open-shell nuclei, this is the first observation of a maximum in the $S$-factor, which signals a strong sub-barrier hindrance. A comparison with the $^{58}$Ni+$^{58}$Ni, $^{58}$Ni+$^{60}$Ni, and $^{58}$Ni+$^{64}$Ni systems indicates a strong dependence of the energy where the hindrance occurs on the stiffness of the interacting nuclei.

C. L. Jiang; K. E. Rehm; R. V. F. Janssens; H. Esbensen; I. Ahmad; B. B. Back; P. Collon; C. N. Davids; J. P. Greene; D. J. Henderson; G. Mukherjee; R. C. Pardo; M. Paul; T. O. Pennington; D. Seweryniak; S. Sinha; Z. Zhou

2004-02-25T23:59:59.000Z

113

Further studies on hydration of alkynes by the PtCl4-CO catalyst  

E-Print Network (OSTI)

for the hydration of alkynes by the PtCl 4 -CO catalystalkynes by the PtCl 4 -CO catalyst in aqueous glyme aalkynes by the PtCl 4 -CO catalyst Osnat Israelsohn a , K.

Israelsohn, Osnat; Vollhardt, K. Peter C.; Blum, Jochanan

2002-01-01T23:59:59.000Z

114

Sulfur Tolerant Pd/Cu and Pd/Au Alloy Membranes for H2 Separation with High Pressure CO2 for Sequestration  

DOE Green Energy (OSTI)

The effect of H{sub 2}S poisoning on Pd, Pd/Cu, and Pd/Au alloy composite membranes prepared by the electroless deposition method on porous Inconel supports was investigated to provide a fundamental understanding of the durability and preparation of sulfur tolerant membranes. X-ray photoelectron spectroscopy (XPS) studies showed that the exposure of pure Pd to 50 ppm H{sub 2}S/H{sub 2} mixtures caused bulk sulfide formation at lower temperatures and surface sulfide formation at higher temperatures. Lower temperatures, longer exposure times, and higher H{sub 2}S concentrations resulted in a higher degree of sulfidation. In a Pd membrane, the bulk sulfide formation caused a drastic irrecoverable H{sub 2} permeance decline and an irreparable loss in selectivity. Pd/Cu and Pd/Au alloy membranes exhibited permeance declines due to surface sulfide formation upon exposure to 50 ppm H{sub 2}S/H{sub 2} gas mixtures. However in contrast to the pure Pd membrane, the permeances of the Pd/Cu and Pd/Au alloy membranes were mostly recovered in pure H{sub 2} and the selectivity of the Pd alloy layers remained essentially intact throughout the characterization in H{sub 2}, He and H{sub 2}S/H{sub 2} mixtures which lasted several thousand hours. The amount of irreversible sulfur poisoning decreased with increasing temperature due to the exothermicity of H{sub 2}S adsorption. Longer exposure times increased the amount of irreversible poisoning of the Pd/Cu membrane but not the Pd/Au membrane. Pd/Au coupon studies of the galvanic displacement method showed that higher Au{sup 3+} concentrations, lower pH values, higher bath temperatures and stirring the bath at a rate of 200 rpm yielded faster displacement rates, more uniform depositions, and a higher Au content within the layers. While 400 C was found to be sufficient to form a Pd/Au alloy on the surface, high temperature X-ray diffraction (HTXRD) studies showed that even after annealing between 500-600 C, the Pd/Cu alloys could have part or all of the surface in the less sulfur resistant {beta} phase.

Yi Hua Ma; Natalie Pomerantz; Chao-Huang Chen

2008-09-30T23:59:59.000Z

115

Composition-Mediated Order-Disorder Transformation in FePt Nanoparticles  

SciTech Connect

Thumbnail image of graphical abstract Heat-treated alloy FePt nanoparticles transform into L10 FePt and mixed L10/L12 FePt3 intermetallic phases. Enrichment in Pt in some nanoparticles, rather than intrinsic thermodynamic effects, drives phase segregation. FePt nanoparticles of uniform, equimolar composition are expected to transform into phase-pure, highly ordered L10 FePt nanoparticles.

Johnston-Peck, Aaron C [ORNL; Cullen, David A [ORNL; Tracy, Joseph B [North Carolina State University

2013-01-01T23:59:59.000Z

116

The Interaction of Dissolved H with Internally Oxidized Pd-Rh Alloys  

DOE Green Energy (OSTI)

Binary Pd-M alloys containing small amounts of readily oxidizable solute metals such as M equals Al, Mg, or Zr, can be internally oxidized to form essentially pure Pd matrices containing a second phase of nano-sized oxide precipitates. During internal oxidation Pd atoms are transported to the surface forming Pd nodules while vacancies are transported from the surface to the metal/oxide interface relieving the compressive stress which develops within the alloy due to the expanding metal oxide precipitates. The Pd alloys that have been studied contain that form very stable oxides.

Shanahan, K.L.

2001-04-20T23:59:59.000Z

117

Monte carlo simulations of segregation in Pt-Re catalyst nanoparticles  

E-Print Network (OSTI)

and design of Pt-Re catalyst nanoparticles. ACKNOWLEDGMENTSJ.H. Sinfelt, Bimetallic Catalysts: Discoveries, concepts,of segregation in Pt-Re catalyst nanoparticles Guofeng Wang

Wang, Guofeng; Van Hove, M.A.; Ross, P.N.; Baskes, M.I.

2004-01-01T23:59:59.000Z

118

Surface Structures of Cubo-octahedral Pt-Mo Catalyst Nanoparticles from Monte Carlo Simulations  

E-Print Network (OSTI)

of Cubo-octahedral Pt-Mo Catalyst Nanoparticles from Montefuel cells, new electrode catalysts that have less preciousto designing Pt bimetallic catalysts is knowledge of the

Wang, Guofeng; Van Hove, M.A.; Ross, P.N.; Baskes, M.I.

2005-01-01T23:59:59.000Z

119

Department of Energy Pt. 824, App. A  

NLE Websites -- All DOE Office Websites (Extended Search)

5 5 Department of Energy Pt. 824, App. A not been paid within sixty calendar days after the assessment has been issued, the DOE shall institute an ac- tion in the appropriate District Court of the United States for an order af- firming the assessment of the civil pen- alty. § 824.15 Collection of civil penalties. If any person fails to pay an assess- ment of a civil penalty after it has be- come a final order or after the appro- priate District Court has entered final judgment for DOE under § 824.14, DOE shall institute an action to recover the amount of such penalty in an appro- priate District Court of the United States. § 824.16 Direction to NNSA contrac- tors. (a) Notwithstanding any other provi- sion of this part, the NNSA Adminis- trator, rather than the Director, signs,

120

Department of Energy Pt. 824, App. A  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

5 5 Department of Energy Pt. 824, App. A not been paid within sixty calendar days after the assessment has been issued, the DOE shall institute an ac- tion in the appropriate District Court of the United States for an order af- firming the assessment of the civil pen- alty. § 824.15 Collection of civil penalties. If any person fails to pay an assess- ment of a civil penalty after it has be- come a final order or after the appro- priate District Court has entered final judgment for DOE under § 824.14, DOE shall institute an action to recover the amount of such penalty in an appro- priate District Court of the United States. § 824.16 Direction to NNSA contrac- tors. (a) Notwithstanding any other provi- sion of this part, the NNSA Adminis- trator, rather than the Director, signs,

Note: This page contains sample records for the topic "ni pd pt" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
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121

Methanol oxidation on PtRu electrodes. Influence of surface structure and Pt-Ru atom distribution  

Science Conference Proceedings (OSTI)

The activities of different types of PtRu catalysts for methanol oxidation are compared. Materials used were: UHV-cleaned PtRu alloys, UHV-evaporated Ru onto Pt(111) as well as adsorbed Ru on Pt(111) prepared with and without additional reduction by hydrogen. Differences in the catalytic activity are observed to depend on the preparation procedure of the catalysts. The dependence of the respective catalytic activities upon the surface composition is reported. UHV-STM data for Pt(111)/Ru show the formation of two- and three-dimensional structures depending on surface coverage. A molecular insight on the electrochemical reaction is given via in situ infrared spectroscopy. Analysis of the data indicates that the most probable rate-determining step is the reaction of adsorbed CO with Ru oxide.

Iwasita, T.; Hoster, H.; John-Anacker, A.; Lin, W.F.; Vielstich, W.

2000-01-25T23:59:59.000Z

122

Neutron Imaging @ SNS (NI@SNS 2008)  

NLE Websites -- All DOE Office Websites (Extended Search)

Neutron Imaging at SNS Workshop (NI@SNS 2008) November 3, 2008 * Building 8600, Central Laboratory & Office Building * Oak Ridge, TN 37831 NI@SNS2008 home Neutron Imaging Agenda...

123

Density Functional Studies of Methanol Decomposition on Subnanometer Pd Clusters  

DOE Green Energy (OSTI)

A density functional theory study of the decomposition of methanol on subnanometer palladium clusters (primarily Pd4) is presented. Methanol dehydrogenation through C-H bond breaking to form hydroxymethyl (CH2OH) as the initial step, followed by steps involving formation of hydroxymethylene (CHOH), formyl (CHO), and carbon monoxide (CO), is found to be the most favorable reaction pathway. A competing dehydrogenation pathway with O-H bond breaking as the first step, followed by formation of methoxy (CH3O) and formaldehyde (CH2O), is slightly less favorable. In contrast, pathways involving C-O bond cleavage are much less energetically favorable, and no feasible pathways involving C-O bond formation to yield dimethyl ether (CH3OCH3) are found. Comparisons of the results are made with methanol decomposition products adsorbed on more extended Pd surfaces; all reaction intermediates are found to bind slightly more strongly to the clusters than to the surfaces.

Mehmood, Faisal; Greeley, Jeffrey P.; Curtiss, Larry A.

2009-12-31T23:59:59.000Z

124

SF 6432-NI (02-22-10)  

interpreted in accordance with laws of New Mexico, and, where appropriate, the United States federal law. NI03 – ASSIGNMENT

125

Interactions of Oxygen and Hydrogen on Pd(111) surface  

DOE Green Energy (OSTI)

The coadsorption and interactions of oxygen and hydrogen on Pd(1 1 1) was studied by scanning tunneling microscopy and density functional theory calculations. In the absence of hydrogen oxygen forms a (2 x 2) ordered structure. Coadsorption of hydrogen leads to a structural transformation from (2 x 2) to a ({radical}3 x {radical}3)R30 degree structure. In addition to this transformation, hydrogen enhances the mobility of oxygen. To explain these observations, the interaction of oxygen and hydrogen on Pd(1 1 1) was studied within the density functional theory. In agreement with the experiment the calculations find a total energy minimum for the oxygen (2 x 2) structure. The interaction between H and O atoms was found to be repulsive and short ranged, leading to a compression of the O islands from (2 x 2) to ({radical}3 x {radical}3)R30 degree ordered structure at high H coverage. The computed energy barriers for the oxygen diffusion were found to be reduced due to the coadsorption of hydrogen, in agreement with the experimentally observed enhancement of oxygen mobility. The calculations also support the finding that at low temperatures the water formation reaction does not occur on Pd(1 1 1).

Demchenko, D.O.; Sacha, G.M.; Salmeron, M.; Wang, L.-W.

2008-06-25T23:59:59.000Z

126

Extended, Continuous Pt Nanostructures in Thick, Dispersed Electrodes  

NLE Websites -- All DOE Office Websites (Extended Search)

Bryan Pivovar (PI) Bryan Pivovar (PI) National Renewable Energy Laboratory Sept 30, 2009 Extended, Continuous Pt Nanostructures in Thick, Dispersed Electrodes This presentation does not contain any proprietary, confidential, or otherwise restricted information Objectives To assist the DOE Fuel Cell Technologies (FCT) Program in meeting cost, durability, and performance targets in the areas of Electrocatalysts and MEAs. Approach: Novel Synthesis and Electrode Studies Pt nanotubes (UC-R) Pt coated carbon nanotubes Synthesis of novel catalysts based on extended surfaces due to 3M's demonstrated improvements in specific activity and durability using similar systems. Electrode architecture design, based on novel catalyst structures that allow thick (~10 µm), dispersed electrodes to

127

Microstructure and Corrosion Behavior of the Cu-Pd-X Ternary Alloys for Hydrogen Separation Membranes  

DOE Green Energy (OSTI)

CuPd alloys are among the most promising candidate materials for hydrogen separation membranes and membrane reactor applications due to their high hydrogen permeability and better sulfur resistance. In order to reduce the Pd content and, therefore, the cost of the membrane materials, efforts have been initiated to develop CuPdM ternary alloys having a bcc structure. The advantages of having Pd as a hydrogen separation membrane are: (1) high hydrogen selectivity; and (2) high hydrogen permeability. The disadvantages are: (1) high cost; (2) hydrogen embrittlement ({alpha} {yields} {beta} Pd hydride); and (3) sulfur poisoning. Experiments (XRD, SEM/EDS) verified that Mg, Al, La, Y and Ti are promising alloying elements to expand the B2 phase region in Cu-Pd binary system. HT-XRD showed that the B2 to FCC transition temperatures for Cu-Pd-X (X = Mg, Al, La, Y and Ti) are higher than that of Cu-Pd binary alloys. While the Cu-50Pd alloy had the highest corrosion resistance to the H2S containing syngas, the Cu-Pd-Mg alloy had a comparable resistance.

O.N. Dogan; M.C. Gao; B.H. Howard

2012-02-26T23:59:59.000Z

128

Table PT1. Energy Production Estimates in Physical Units, Michigan ...  

U.S. Energy Information Administration (EIA)

Table PT1. Energy Production Estimates in Physical Units, Michigan, 1960 - 2011 1960 0 20,790 15,899 NA 1961 0 27,697 18,901 NA 1962 0 28,987 17,114 NA

129

Surface characterization of Pd/Al2O3 sorbents for mercury capture from fuel gas  

SciTech Connect

The surface composition of a series of Pd/alumina sorbents has been characterized to better understand the factors influencing their ability to adsorb mercury from fuel gas. Both a temperature effect and a dispersion effect were found. Maximum adsorption of Hg occurred at the -lowest temperature tested, 204°C, and decreased with increasing temperatures. Maximum adsorption of Hg on a per-atom basis of Pd is observed at low loadings of Pd ( < 8.5% Pd) due to better dispersion of Pd at those loadings; a change in its partitioning occurs at higher loadings. The presence of H2S 'in the fuel gas acts to promote the adsorption of Hg through its association with Hg in the Pd lattice.

Baltrus, J.P.; Granite, E.J.; Stanko, D.C.; Pennline, H.W.

2008-01-01T23:59:59.000Z

130

Hydrogenation of Acetylene-Ethylene Mixtures over Pd and Pd-Ag Alloys: First-Principles Based Kinetic Monte Carlo Simulations  

DOE Green Energy (OSTI)

The kinetics for the selective hydrogenation of acetylene-ethylene mixtures over model Pd(111) and bimetallic Pd-Ag alloy surfaces were examined using first principles based kinetic Monte Carlo (KMC) simulations to elucidate the effects of alloying as well as process conditions (temperature and hydrogen partial pressure). The mechanisms that control the selective and unselective routes which included hydrogenation, dehydrogenation and C-?C bond breaking pathways were analyzed using first-principle density functional theory (DFT) calculations. The results were used to construct an intrinsic kinetic database that was used in a variable time step kinetic Monte Carlo simulation to follow the kinetics and the molecular transformations in the selective hydrogenation of acetylene-ethylene feeds over Pd and Pd-Ag surfaces. The lateral interactions between coadsorbates that occur through-surface and through-space were estimated using DFT-parameterized bond order conservation and van der Waal interaction models respectively. The simulation results show that the rate of acetylene hydrogenation as well as the ethylene selectivity increase with temperature over both the Pd(111) and the Pd-Ag/Pd(111) alloy surfaces. The selective hydrogenation of acetylene to ethylene proceeds via the formation of a vinyl intermediate. The unselective formation of ethane is the result of the over-hydrogenation of ethylene as well as over-hydrogenation of vinyl to form ethylidene. Ethylidene further hydrogenates to form ethane and dehydrogenates to form ethylidyne. While ethylidyne is not reactive, it can block adsorption sites which limit the availability of hydrogen on the surface and thus act to enhance the selectivity. Alloying Ag into the Pd surface decreases the overall rated but increases the ethylene selectivity significantly by promoting the selective hydrogenation of vinyl to ethylene and concomitantly suppressing the unselective path involving the hydrogenation of vinyl to ethylidene and the dehydrogenation ethylidene to ethylidyne. This is consistent with experimental results which suggest only the predominant hydrogenation path involving the sequential addition of hydrogen to form vinyl and ethylene exists over the Pd-Ag alloys. Ag enhances the desorption of ethylene and hydrogen from the surface thus limiting their ability to undergo subsequent reactions. The simulated apparent activation barriers were calculated to be 32-44 kJ/mol on Pd(111) and 26-31 kJ/mol on Pd-Ag/Pd(111) respectively. The reaction was found to be essentially first order in hydrogen over Pd(111) and Pd-Ag/Pd(111) surfaces. The results reveal that increases in the hydrogen partial pressure increase the activity but decrease ethylene selectivity over both Pd and Pd-Ag/Pd(111) surfaces. Pacific Northwest National Laboratory is operated by Battelle for the US Department of Energy.

Mei, Donghai; Neurock, Matthew; Smith, C Michael

2009-10-22T23:59:59.000Z

131

Spin observables for pion production from pd collisions  

E-Print Network (OSTI)

We have calculated the proton analyzing power A_{y0} of the pion-production reaction from pd collisions for one energy close to threshold and for another in the region of the $\\Delta$-resonance. A fair reproduction of the experimental data could be obtained in both cases with a model which includes isoscalar and isovector $\\pi N$ rescatterings in s waves, as well as the p-wave rescattering mechanisms mediated by the $\\pi NN$ and $\\pi N \\Delta$ vertices. For the analyzing power at threshold we found that the initial-state interaction (ISI) is also quite important.

Canton, L; Schadow, W; Svenne, J P

2001-01-01T23:59:59.000Z

132

Annealing, lattice disorder and non-Fermi liquid behavior in UCu4Pd  

Science Conference Proceedings (OSTI)

The magnetic and electronic properties of non-Fermi liquid UCu{sub 4Pd} depend on annealing conditions. Local structural changes due to this annealing are reported from UL{sub III}- and Pd K-edge x-ray absorption fine-structure measurements. In particular, annealing decreases the fraction of Pd atoms on nominally Cu 16e sites and the U-Cu pair-distance distribution width. This study provides quantitative information on the amount of disorder in UCu{sub 4Pd} and allows an assessment of its possible importance to the observed non-Fermi liquid behavior.

Booth, C.H.; Scheidt, E.-W.; Killer, U.; Weber, A.; Kehrein, S.

2002-07-30T23:59:59.000Z

133

Improving the phase stability and oxidation resistance of B-NiAl  

SciTech Connect

High temperature alloys are essential to many industries that require a stable material to perform in harsh oxidative environments. Many of these alloys are suited for specific applications such as jet engine turbine blades where most other materials would either melt or oxidize and crumble (1). These alloys must have a high melting temperature, excellent oxidation resistance, good creep resistance, and decent fracture toughness to be successfully used in such environments. The discovery of Ni based superalloys in the 1940s revolutionized the high temperature alloy industry and there has been continued development of these alloys since their advent (2). These materials are capable of operating in oxidative environments in the presence of combustion gases, water vapor and at temperatures around 1050 C. Demands for increased f uel efficiency, however, has highlighted the need for materials that can be used under similar atmospheres and at temperatures in excess of 1200 C. The current Ni based superalloys are restricted to lower temperatures due to the presence of a number of low melting phases that result in softening of the alloys above 1000 C. Therefore, recent research has been aimed at exploring and developing newer alloy systems that can meet the escalating requirements. This thesis comprises a part of such an effort. The motivation of this work is to develop a novel high temperature alloy system that shows improved performance at higher temperatures than the currently employed alloys. The desired alloy should be in accordance with the requirements established in the National Energy Technology Laboratory (NETL) FutureGen program having an operating temperature around 1300 C. Alloys based on NiAl offer significant potential payoffs as structural materials in gas turbine applications due to a unique range of physical and mechanical properties. Alloying additions to NiAl could be used to further improve the pertinent properties that currently limit this system from replacing Ni based superalloys. Modifications to NiAl were explored to increase the phase stability and oxidation resistance which would allow these alloys to be used at even higher temperatures yielding greater efficiencies. The extended Miedema model was an effective tool that screened all of the potential phase space for ternary substitutions to NiAl and found the few potential systems worth further investigation. After production of the alloys it was determined that Ir, Rh, and Pd were the top candidates for substitution on Ni site up to 12 at%. The melting temperature of NiAl could be increased as much as 150 C with 12 at% Ir and 130 C with 12 at% Rh substitution. Pall adium on the other hand decreased the melting temperature by 50 C at the 12 at% substitution level. The grain size was found to have a profound influence on the oxidation resistance. Both Ir and Rh substitutions resulted in finer grain sizes compared to Pd substitutions or base NiAl. The grain size increased drastically during high temperature annealing with the PGM substitutions hindering grain growth only slightly. However, the addition of 0.05 at% Hf limited the grain growth dramatically during high temperature annealing. NiAl inherently has respectable oxidation resistance up to 1100 C. It was found through experimental testing that both Ir and Rh substitutions improve the oxidation resistance of NiAl at ultra-high temperatures with Ir performing the best. Both PGM substitutions decreased the growth rate as well as forming a more adherent oxide scale. Pd substitutions appeared to have a negligible effect to the oxidation resistance of NiAl. Hafnium addition of 0.05 at% was found to decrease the oxidation rate as well as increase the scale adherence. The combination of both Ir substitution (6-9 at%) and Hf addition (0.05 at%) produced the alloy with the best oxidation resistance. Although improvements in phase stability and oxidation resistance have been made to the NiAl system, more development and testing are still needed. Two major issues yet to be resolved are the low fracture toughn

Brammer, Travis

2011-08-15T23:59:59.000Z

134

Diffusion in L12 Structures: A Comparison of Ni3Al, Ni3Ga and Ni3Ge  

Science Conference Proceedings (OSTI)

... that while the diffusivities of the majority component Ni in these compounds are similar, ... First Order Structural Transformations in Symmetrical Tilt S5 Grain ...

135

Carbon-Hydrogen Bond Activation and Cyclodehydrogenation Reactions of Cyclic C8 Hydrocarbons on Pt(111)  

E-Print Network (OSTI)

, but do not contribute to steady-state catalytic reforming rates. The high reactivity of Pd surfaces in C

Girolami, Gregory S.

136

Preparation and characterization of Ni(OH)2 and NiO mesoporous nanosheets  

Science Conference Proceedings (OSTI)

Mesoporous nanosheets of single-crystalline ?-nickel hydroxide (?-Ni(OH)2) were successfully synthesized via a facile hydrothermal method using Ni(NO3)2 ? 6H2O as precursor in a mixed solution ...

Changyu Li; Shouxin Liu

2012-01-01T23:59:59.000Z

137

Surface Structures of Cubo-octahedral Pt-Mo Catalyst Nanoparticles from Monte Carlo Simulations  

DOE Green Energy (OSTI)

The surface structures of cubo-octahedral Pt-Mo nanoparticles have been investigated using the Monte Carlo method and modified embedded atom method potentials that we developed for Pt-Mo alloys. The cubo-octahedral Pt-Mo nanoparticles are constructed with disordered fcc configurations, with sizes from 2.5 to 5.0 nm, and with Pt concentrations from 60 to 90 at. percent. The equilibrium Pt-Mo nanoparticle configurations were generated through Monte Carlo simulations allowing both atomic displacements and element exchanges at 600 K. We predict that the Pt atoms weakly segregate to the surfaces of such nanoparticles. The Pt concentrations in the surface are calculated to be 5 to 14 at. percent higher than the Pt concentrations of the nanoparticles. Moreover, the Pt atoms preferentially segregate to the facet sites of the surface, while the Pt and Mo atoms tend to alternate along the edges and vertices of these nanoparticles. We found that decreasing the size or increasing the Pt concentration leads to higher Pt concentrations but fewer Pt-Mo pairs in the Pt-Mo nanoparticle surfaces.

Wang, Guofeng; Van Hove, M.A.; Ross, P.N.; Baskes, M.I.

2005-03-31T23:59:59.000Z

138

Elliptic flow orientation, saturation and low $p_t$ behavior  

E-Print Network (OSTI)

We consider general model with factorization between macroscopic flow and matter decay distribution. We show universality of $p_t^2$ behavior of elliptic flow at small $p_t$ for identified final particles in the symmetric nucleus collision. At high $p_t$ we compare non-relativistic and relativistic models for boosted decay distribution. In the relativistic models with distribution having power-like tail we show existence of elliptic flow saturation. This means that the elliptic flow value $v_2$ tend to constant at high $p_t$. We discuss the importance of determination of elliptic flow orientation which can help us to compare different models. For example, we introduce potential expansion model which can reproduce azimuthal asymmetry but based on the assumption that there are only cold strong forces and no thermalization. This model show opposite sign of elliptic flow orientation in comparison with thermal model. We also show that at small $p_t$ sign of elliptic flow can change due to sign of second derivative of decay distribution. This fact tell us that we must more carefully link elliptic flow sign and properties of the model.

V. A. Abramovsky; A. V. Popov

2003-12-26T23:59:59.000Z

139

Online PD Monitoring and Analysis for Step-up Transformers of Hydropower Plant  

Science Conference Proceedings (OSTI)

As we known, to evaluate and diagnosis the insulation faults of large-size power transformers, partial discharges (PDs) can be detected via ultra high frequency (UHF) technique. In this paper, an UHF PD online monitoring system was developed for large-size ... Keywords: Partial Discharge (PD), Transformers, Online monitoring, Ultra high frequency (UHF), Correlative analysis

Wan Yuan; Gong Chuangli; Wei Zhipeng; Deng Pengcheng

2011-01-01T23:59:59.000Z

140

Pitch rate damping of an aircraft by fuzzy and classical PD controller  

Science Conference Proceedings (OSTI)

Aircraft dynamics are in general nonlinear, time varying, and uncertain. A control system (classical control systems) designed for a flight condition, may not provide the desired stability and performance characteristics in case of deviation from the ... Keywords: aircraft, classical PD control, flight control, fuzzy and fuzzy PD control, pitch rate

Yasemin Isik

2010-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "ni pd pt" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

Novel Audio Amplifier System Using Opt-Coupling of LED and PD  

Science Conference Proceedings (OSTI)

This paper proposes a completely new and simple audio amplifier system using the opt-coupling of LED (Light Emitting Diode) and PD (Photo Diode), without using conventional devices such as Transistor IC and Vacuum Tube. This paper also explains that ... Keywords: audio amplifier, LED and PD, opt-coupling, distar, transistor, low noise, kansei product

Junichi Fujita, Tetsuo Hattori, Kensho Okamoto

2013-07-01T23:59:59.000Z

142

Development of an inter-atomic potential for the Pd-H binary system.  

DOE Green Energy (OSTI)

Ongoing research at Sandia National Laboratories has been in the area of developing models and simulation methods that can be used to uncover and illuminate the material defects created during He bubble growth in aging bulk metal tritides. Previous efforts have used molecular dynamics calculations to examine the physical mechanisms by which growing He bubbles in a Pd metal lattice create material defects. However, these efforts focused only on the growth of He bubbles in pure Pd and not on bubble growth in the material of interest, palladium tritide (PdT), or its non-radioactive isotope palladium hydride (PdH). The reason for this is that existing inter-atomic potentials do not adequately describe the thermodynamics of the Pd-H system, which includes a miscibility gap that leads to phase separation of the dilute (alpha) and concentrated (beta) alloys of H in Pd at room temperature. This document will report the results of research to either find or develop inter-atomic potentials for the Pd-H and Pd-T systems, including our efforts to use experimental data and density functional theory calculations to create an inter-atomic potential for this unique metal alloy system.

Zimmerman, Jonathan A.; Hoyt, Jeffrey John (McMaster University, Hamilton, Ontario, Canada); Leonard, Francois Leonard; Griffin, Joshua D.; Zhou, Xiao Wang

2007-09-01T23:59:59.000Z

143

Why Is Pt So Unique A Chemical Physics Approach  

NLE Websites -- All DOE Office Websites (Extended Search)

Is Pt So Unique Is Pt So Unique A Chemical Physics Approach Philip N. Ross, Jr. Materials Sciences Division Lawrence Berkeley National Laboratory Berkeley, CA 94708 Outline * A brief history of electrode kinetics * Reaction pathway for oxygen reduction * Effect of pH * Systematic trends across Periodic Table * One electron makes a big difference d 9 s 1 versus d 10 s 1 * Pt at the top of the Volcano Curve Mechanism of the ORR at metal electrodes Addition of first electron needed to break O-O bond Rate limiting step in electrochemical reduction of O 2 is 1 st electron transfer O 2 + - → (O 2 - ) sol Outer Sphere E 0 ' =-0.3 V) O 2 + - → (O 2 - ) ads Inner Sphere (E 0 ' + ∆G ad /F) O 2 - adsorption strength nic properties of the electrode material Establish general trends across Periodic Table using

144

Radiosonde observations at Pt. Reyes and cloud properties retrieved from  

NLE Websites -- All DOE Office Websites (Extended Search)

Radiosonde observations at Pt. Reyes and cloud properties retrieved from Radiosonde observations at Pt. Reyes and cloud properties retrieved from GOES-WEST Inoue, Toshiro MRI/JMA Category: Field Campaigns Low-level cloud formed off the west coast of continents plays an important role in general circulation and climate. Marine Stratus Radiation Aerosol and Drizzle (MASRAD) was conducted at the ARM mobile site deployed at Pt Reyes, California during April to September. Here, we studied the relationship between meteorological parameters observed by GPS sonde and cloud properties observed from GOES-WEST during the MASRAD intensive operational period. Cloud properties are retrieved from VISST (Visible Infrared Solar-infrared Split window Technique). The vertical profile of stability, relative humidity (RH) and wind speed observed by GPS sonde are

145

Nearly itinerant ferromagnetism in CaNi2 and CaNi3  

SciTech Connect

Single crystals of CaNi2 and CaNi3 are successfully grown out of excess Ca. Both compounds manifest a metallic ground state with enhanced, temperature-dependent magnetic susceptibility. The relatively high Stoner factors of Z=0.79 and 0.87 found for CaNi2 and CaNi3, respectively, reveal their close vicinity to ferromagnetic instabilities. The pronounced field dependence of the magnetic susceptibility of CaNi3 at low temperatures (T<25 K) suggests strong ferromagnetic fluctuations. A corresponding contribution to the specific heat with a temperature dependence of T3lnT is also observed.

Jesche, Anton; Dennis, Kevin W.; Kreyssig, Andreas; Canfield, Paul C.

2012-06-26T23:59:59.000Z

146

Development of Ni Base Superalloy for Industrial Gas Turbine  

Science Conference Proceedings (OSTI)

In response to this demand, Ni-base superalloys have been developed by MHI's alloy design system. These Ni-base superalloys have been applied to rotating ...

147

Direct photons at low $p_{T}$ measured in PHENIX  

E-Print Network (OSTI)

Direct photon spectra measured at small $p_T$ in p+p, d+Au and Au+Au collisions at $\\sqrt{s_{NN}}=200$ GeV are presented. Several measurement techniques including statistical subtraction, tagging, and internal and external conversion were applied and found to produce consistent results. The p+p and d+Au results are found to be in very good agreement with pQCD predictions over the entire $p_T$ range. No excess of direct photons in Au+Au collisions with respect to binary scaled d+Au data is observed within systematic errors.

D. Peressounko

2007-02-12T23:59:59.000Z

148

Electrodeposited NiCo/Cu Superlattices  

Science Conference Proceedings (OSTI)

NiCo/Cu superlattices were electrodeposited on polycrystalline Cu substrates from a single electrolyte under potentiostatic control. The X-ray diffraction (XRD) patterns showed that NiCo/Cu superlattices have the same crystal structure and texture as in their substrates. The films exhibited giant magnetoresistance (GMR) or anisotropic magnetoresistance (AMR), depending on the Cu layer thicknesses.

Safak, M.; Alper, M. [Department of Physics, Faculty of Science and Literature, University of Uludag, Goeruekle, Bursa (Turkey)

2007-04-23T23:59:59.000Z

149

48pt0ValueEngineeringinMOContracts.pdf | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Technology Centers Field Sites Power Marketing Administration Other Agencies You are here Home 48pt0ValueEngineeringinMOContracts.pdf 48pt0ValueEngineeringinMOContracts.pdf...

150

Polyol-free synthesis of uniformly dispersed Pt/graphene oxide electrocatalyst by sulfuric acid treatment  

Science Conference Proceedings (OSTI)

Polyol-free synthesis of highly loaded Pt catalysts on sulfuric-acid-treated graphene oxide (SGO) was reported. Sulfuric acid treatment increased the surface hydroxyl groups on graphene oxide (GO), which contributed to the reduction of Pt precursors ...

Tae Kyu Lee, Hyang Jin Park, Min Ki Kwon, Ju Hae Jung, Junbom Kim, Seung Hyun Hur

2012-01-01T23:59:59.000Z

151

L10-FePt Media for Next-Generation Data Storage Devices  

E-Print Network (OSTI)

MgO/Fe 55 Pt 45 (no Ar milling, no Ta). The second set ofPt 45 , with substrate Ar-ion milling performed before filmdeposition (with Ar milling, no Ta). The third set of

Fernandez, Robert Anthony

2010-01-01T23:59:59.000Z

152

Microsoft Word - AcqGuide70pt31B.doc | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Microsoft Word - AcqGuide70pt31B.doc More Documents & Publications OPAM Policy Acquisition Guides Microsoft Word - AcqGuide70pt31A.doc PolicyFlash2010-12(2).pdf...

153

Microsoft Word - AcqGuide16pt1 Nov 2010 | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

- AcqGuide16pt1 Nov 2010 Microsoft Word - AcqGuide16pt1 Nov 2010 More Documents & Publications OPAM Policy Acquisition Guides Chapter 16 - Types of Contracts Policy Flash 2012-56...

154

Model for the Prediction of the Hydriding Thermodynamics of Pd-Rh-Co Ternary Alloys  

DOE Green Energy (OSTI)

A dilute solution model (with respect to the substitutional alloying elements) has been developed, which accurately predicts the hydride formation and decomposition thermodynamics and the storage capacities of dilute ternary Pd-Rh-Co alloys. The effect of varying the rhodium and cobalt compositions on the thermodynamics of hydride formation and decomposition and hydrogen capacity of several palladium-rhodium-cobalt ternary alloys has been investigated using pressure-composition (PC) isotherms. Alloying in the dilute regime (<10 at.%) causes the enthalpy for hydride formation to linearly decrease with increasing alloying content. Cobalt has a stronger effect on the reduction in enthalpy than rhodium for equivalent alloying amounts. Also, cobalt reduces the hydrogen storage capacity with increasing alloying content. The plateau thermodynamics are strongly linked to the lattice parameters of the alloys. A near-linear dependence of the enthalpy of hydride formation on the lattice parameter was observed for both the binary Pd-Rh and Pd-Co alloys, as well as for the ternary Pd-Rh-Co alloys. The Pd-5Rh-3Co (at. %) alloy was found to have similar plateau thermodynamics as a Pd-10Rh alloy, however, this ternary alloy had a diminished hydrogen storage capacity relative to Pd-10Rh.

Teter, D.F.; Thoma, D.J.

1999-03-01T23:59:59.000Z

155

Table PT1. Energy Production Estimates in Physical Units, Ohio ...  

U.S. Energy Information Administration (EIA)

Table PT1. Energy Production Estimates in Physical Units, Ohio, 1960 - 2011 1960 33,957 36,074 5,405 NA 1961 32,226 36,423 5,639 NA 1962 34,125 36,747 5,835 NA

156

Table PT2. Energy Production Estimates in Trillion Btu, Oklahoma ...  

U.S. Energy Information Administration (EIA)

Table PT2. Energy Production Estimates in Trillion Btu, Oklahoma, 1960 - 2011 1960 33.9 902.0 1,118.9 0.0 NA 17.8 17.8 2,072.6 1961 26.1 976.9 1,119.9 0.0 NA 20.2 20 ...

157

Table PT2. Energy Production Estimates in Trillion Btu, California ...  

U.S. Energy Information Administration (EIA)

Table PT2. Energy Production Estimates in Trillion Btu, California, 1960 - 2011 1960 0.0 589.7 1,771.0 (s) NA 270.2 270.2 2,630.9 1961 0.0 633.8 1,737.7 0.1 NA 248.2 ...

158

Table PT2. Energy Production Estimates in Trillion Btu, Delaware ...  

U.S. Energy Information Administration (EIA)

Table PT2. Energy Production Estimates in Trillion Btu, Delaware, 1960 - 2011 1960 0.0 0.0 0.0 0.0 NA 5.0 5.0 5.0 1961 0.0 0.0 0.0 0.0 NA 5.1 5.1 5.1

159

Table PT2. Energy Production Estimates in Trillion Btu, Texas ...  

U.S. Energy Information Administration (EIA)

Table PT2. Energy Production Estimates in Trillion Btu, Texas, 1960 - 2011 1960 26.4 6,610.7 5,379.4 0.0 NA 50.2 50.2 12,066.6 1961 26.5 6,690.2 5,447.3 0.0 NA 52.0 ...

160

Table PT2. Energy Production Estimates in Trillion Btu, Indiana ...  

U.S. Energy Information Administration (EIA)

Table PT2. Energy Production Estimates in Trillion Btu, Indiana, 1960 - 2011 1960 346.3 0.3 69.9 0.0 NA 24.6 24.6 441.1 1961 336.7 0.4 66.7 0.0 NA 24.2 24.2 428.0

Note: This page contains sample records for the topic "ni pd pt" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Table PT2. Energy Production Estimates in Trillion Btu, Oregon ...  

U.S. Energy Information Administration (EIA)

Table PT2. Energy Production Estimates in Trillion Btu, Oregon, 1960 - 2011 1960 0.0 0.0 0.0 0.0 NA 190.5 190.5 190.5 1961 0.0 0.0 0.0 0.0 NA 188.9 188.9 188.9

162

Table PT2. Energy Production Estimates in Trillion Btu, Arizona ...  

U.S. Energy Information Administration (EIA)

Table PT2. Energy Production Estimates in Trillion Btu, Arizona, 1960 - 2011 1960 0.1 0.0 0.4 0.0 NA 36.2 36.2 36.7 1961 0.0 0.0 0.4 0.0 NA 35.1 35.1 35.5

163

Table PT1. Energy Production Estimates in Physical Units, Texas ...  

U.S. Energy Information Administration (EIA)

Table PT1. Energy Production Estimates in Physical Units, Texas, 1960 - 2011 1960 2,098 5,892,704 927,479 NA 1961 2,108 5,963,605 939,191 NA 1962 2,054 6,080,210 ...

164

Comparison of Cobalt and Nickel Complexes with Sterically Demanding Cyclic Diphosphine Ligands: Electrocatalytic H2 Production by [Co(PtBu2NPh2)(CH3CN)3](BF4)2  

DOE Green Energy (OSTI)

The cyclic diphosphine ligands PtBu2NPh2 and PtBu2NBz2 have been synthesized and used to prepare new complexes of Co(II) and Ni(II) with the formula [M(PtBu2NR2)(CH3CN)n](BF4)2 (n = 2, 3). The products have been characterized by variable temperature NMR data, X-ray diffraction studies, and cyclic voltammetry, and properties of the new complexes have been compared with previously studied complexes containing PPh2NR2 ligands. The variation of either phosphorus or nitrogen substituents in these ligands can result in significant differences in the structure, electrochemistry and reactivity of the metal complexes. [Co(PtBu2NPh2)(CH3CN)3](BF4)2 is found to be an effective electrocatalyst for the formation of hydrogen using bromoanilinium tetrafluoroborate as the acid, with a turnover frequency of 62 s-1 and an overpotential of 160 mV, and these cobalt derivatives are a promising class of catalysts for further study and optimization. This work was supported by the US Department of Energy Basic Energy Sciences' Chemical Sciences, Geosciences & Biosciences Division. Pacific Northwest National Laboratory is operated by Battelle for the US Department of Energy. This material is based upon work supported as part of the Center for Molecular Electrocatalysis, an Energy Frontier Research Center funded by the US Department of Energy, Office of Science, Office of Basic Energy Sciences.

Wiedner, Eric S.; Yang, Jenny Y.; Dougherty, William G.; Kassel, W. S.; Bullock, R. Morris; Rakowski DuBois, Mary; DuBois, Daniel L.

2010-11-08T23:59:59.000Z

165

PtRu/C electrocatalysts prepared using gamma and electron beam irradiation for methanol electrooxidation  

Science Conference Proceedings (OSTI)

PtRu/C electrocatalysts (carbon-supported PtRu nanoparticles) were prepared in a single step submitting water/2-propanol mixtures containing Pt(IV) and Ru(III) ions and the carbon support to gamma and electron beam irradiation. The electrocatalysts were ...

Dionisio F. Silva, Adriana N. Geraldes, Eddy S. Pino, Almir Oliveira Neto, Marcelo Linardi, Estevam V. Spinacé

2012-01-01T23:59:59.000Z

166

High pressure study of changes in energy and intensity of excitations in crystalline metal glyoximes  

SciTech Connect

The effect of high pressure has been measured on the energy and integrated intensity of electronic excitations of several layered crystals of glyoximes containing Ni, Pd, or Pt. Large changes in both energy and intensity were observed, both of which were completely reversible. The shifts in energy with pressure, are explained in terms of the relative spatial extent of the outer d and p orbitals of Ni, Pd, and Pt. The effects of back donation from the ligands and intensity borrowing from the higher energy charge transfer excitations are considered as possible causes of the observed intensity changes. It was concluded that intensity borrowing was the major cause of the observed changes.

Tkacz, M.; Drickamer, H.G.

1986-07-15T23:59:59.000Z

167

Hydrogen Induced C-C, C-N, & C-S Bond Activation on Pt & Ni Surfaces  

SciTech Connect

The primary reactions investigated were chosen based on their importance in fuel and chemical production as well as in environmental remediation, and include reactions for hydrodesulfurization (HDS), hydrodenitrogenation (HDN), carbon-carbon hydrogenolysis, and hydrocarbon oxidation.

Gland, J. L.

2004-07-29T23:59:59.000Z

168

ARPA-e's "PD Roadshow" | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

ARPA-e's "PD Roadshow" ARPA-e's "PD Roadshow" ARPA-e's "PD Roadshow" November 4, 2010 - 3:36pm Addthis Andy Oare Andy Oare Former New Media Strategist, Office of Public Affairs At the end of October, the Advanced Research Projects Agency's (ARPA-E) Program Directors (PDs) launched the "PD Roadshow" - a series of day-long campus visits to top science and engineering schools. Meeting with university students and faculty, we will use this as an opportunity to exchange ideas with the next generation of energy innovators, and introduce ARPA-E's role in advancing innovation. ARPA-E kicked off the tour with a visit to Cornell University on October 21. On each visit, PDs and an ARPA-E Fellow will share meals with students and staff, meet with university researchers and present a seminar on ARPA-E's

169

A Multi-Ligand Based Pd Catalyst for C–N Cross-Coupling Reactions  

E-Print Network (OSTI)

An alternative approach to catalyst development, which led to a Pd catalyst based on two biarylphosphine ligands for C?N cross-coupling reactions, is reported. By effectively being able to take the form of multiple catalysts ...

Fors, Brett P.

170

The Extension of P.D. Thompson' Scheme to Multiple Times  

Science Conference Proceedings (OSTI)

P.D. Thompson devised a scheme to correct imperfect analyses of a conservative quantity at two observation times. His scheme has been extended to include a sequence of observation times. When the times are equally spaced, the governing adjustment ...

John M. Lewis; Lee Panetta

1983-09-01T23:59:59.000Z

171

Process design and modeling for the production of triacylglycerols (TAGs) in Rhodococcus opacus PD630  

E-Print Network (OSTI)

The oleaginous microorganism Rhodococcus opacus PD630 was used to study the characteristics and kinetics of the accumulation of triacylglycerols (TAGs) in cells. In this process, accumulation of TAG is stimulated when a ...

Miller, Neidi

2012-01-01T23:59:59.000Z

172

Comparative and Functional Genomics of Rhodococcus opacus PD630 for Biofuels Development  

E-Print Network (OSTI)

The Actinomycetales bacteria Rhodococcus opacus PD630 and Rhodococcus jostii RHA1 bioconvert a diverse range of organic substrates through lipid biosynthesis into large quantities of energy-rich triacylglycerols (TAGs). ...

Ghiviriga, Ion

173

A New Biarylphosphine Ligand for the Pd-Catalyzed Synthesis of Diaryl Ethers under Mild Conditions  

E-Print Network (OSTI)

A new bulky biarylphosphine ligand (L8) has been developed that allows the Pd-catalyzed C–O cross-coupling of a wide range of aryl halides and phenols under milder conditions than previously possible. A direct correlation ...

Salvi, Luca

174

ARPA-e's "PD Roadshow" | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

e's "PD Roadshow" e's "PD Roadshow" ARPA-e's "PD Roadshow" November 4, 2010 - 3:36pm Addthis Andy Oare Andy Oare Former New Media Strategist, Office of Public Affairs At the end of October, the Advanced Research Projects Agency's (ARPA-E) Program Directors (PDs) launched the "PD Roadshow" - a series of day-long campus visits to top science and engineering schools. Meeting with university students and faculty, we will use this as an opportunity to exchange ideas with the next generation of energy innovators, and introduce ARPA-E's role in advancing innovation. ARPA-E kicked off the tour with a visit to Cornell University on October 21. On each visit, PDs and an ARPA-E Fellow will share meals with students and staff, meet with university researchers and present a seminar on ARPA-E's

175

Phase Field Simulation of Ni4Ti3 Precipitation in Porous NiTi Shape ...  

Science Conference Proceedings (OSTI)

Generally, porous NiTi alloys may undergo thermomechnical treatment which .... of First Derivative of Dilatation in Low Carbon Steels Multi-Phase Presenting.

176

Solidification and Microstructure Evaluation of the Ni-Ga and Co-Ni ...  

Science Conference Proceedings (OSTI)

Ni-Ga binary system is thus one of the basic binary system which forms the dominated ? ... The Effects of Natural and Marangoni Convection on the Resultant ...

177

Layering and temperature-dependent magnetization and anisotropy of naturally produced Ni/NiO multilayers  

Science Conference Proceedings (OSTI)

Ni/NiO multilayers were grown by magnetron sputtering at room temperature, with the aid of the natural oxidation procedure. That is, at the end of the deposition of each single Ni layer, air is let to flow into the vacuum chamber through a leak valve. Then, a very thin NiO layer ({approx}1.2 nm) is formed. Simulated x-ray reflectivity patterns reveal that layering is excellent for individual Ni-layer thickness larger than 2.5 nm, which is attributed to the intercalation of amorphous NiO between the polycrystalline Ni layers. The magnetization of the films, measured at temperatures 5-300 K, has almost bulk-like value, whereas the films exhibit a trend to perpendicular magnetic anisotropy (PMA) with an unusual significant positive interface anisotropy contribution, which presents a weak temperature dependence. The power-law behavior of the multilayers indicates a non-negligible contribution of higher order anisotropies in the uniaxial anisotropy. Bloch-law fittings for the temperature dependence of the magnetization in the spin-wave regime show that the magnetization in the multilayers decreases faster as a function of temperature than the one of bulk Ni. Finally, when the individual Ni-layer thickness decreases below 2 nm, the multilayer stacking vanishes, resulting in a dramatic decrease of the interface magnetic anisotropy and consequently in a decrease of the perpendicular magnetic anisotropy.

Pappas, S. D.; Trachylis, D.; Velgakis, M. J. [Laboratory of High-Tech Materials, School of Engineering, University of Patras, 26504 Patras (Greece); Kapaklis, V.; Joensson, P. E.; Papaioannou, E. Th. [Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala (Sweden); Delimitis, A. [Chemical Process Engineering Research Institute (CPERI), Centre for Research and Technology Hellas (CERTH), 57001 Thermi, Thessaloniki (Greece); Poulopoulos, P. [Laboratory of High-Tech Materials, School of Engineering, University of Patras, 26504 Patras (Greece); Institut fuer Experimentalphysik, Freie Universitaet Berlin, Arnimallee 14, D-14195 Berlin-Dahlem (Germany); Materials Science Department, University of Patras, 26504 Patras (Greece); Fumagalli, P. [Institut fuer Experimentalphysik, Freie Universitaet Berlin, Arnimallee 14, D-14195 Berlin-Dahlem (Germany); Politis, C. [Laboratory of High-Tech Materials, School of Engineering, University of Patras, 26504 Patras (Greece); Department of Materials Science and Engineering, University of Texas at Arlington, Arlington, Texas 76019 (United States)

2012-09-01T23:59:59.000Z

178

Transitions magntiques dans des alliages Pd-Co hydrogns B. Souffach et J. P. Burger  

E-Print Network (OSTI)

magnétiques du type verre de spin dans les alliages Pd-Co hydro- génés. Les températures d'ordre observées'abaisser considerablement la densite d'etats au niveau de Fermi car 1'electron ajoute par chaque atome d'hydrogene contribue hydro- g6nation du magnetisme d'alliages a base de Pd [5, 6]. Nous nous proposons surtout d'etendre nos

Paris-Sud XI, Université de

179

On the differences in the reaction mechanism for CO and CO/H{sub 2} electrooxidation on PtRu and PtSn alloy electrodes  

DOE Green Energy (OSTI)

Electrooxidation kinetics of mixtures of carbon monoxide and hydrogen were studied on well-characterized surfaces of Pt and alloys of PtRu and PtSn in 0.5 M H{sub 2}SO{sub 4} at room temperature and 60 C. The alloy electrode surfaces were prepared in UHV by sputter/anneal cycles and their surface compositions were determined via low energy ion scattering. Subsequently, the electrodes were transferred contamination-free from UHV into a rotating disk electrode (RDE) configuration in a conventional electrochemical cell and their activity was measured both by CO stripping voltammetry and under the continuous flow of CO and CO/H{sub 2} gas mixtures in RDE-experiments. The overpotential for the continuous oxidation of pure CO on PtSn electrodes with a Sn surface composition of x{sub Sn,s} {approximately} 0.2 is significantly smaller than on PtRu alloys (x{sub Ru,s} {approximately} 0.5) and on pure Pt. The reaction order with respect to solution phase CO is negative on PtRu alloys due to the competition between OH{sub ads} nucleation and CO adsorption on Ru surface atoms. Owing to the lack of CO adsorption on OH{sub ads}-providing Sn surface atoms, the reaction order with respect to CO is positive on PtSn electrodes. Therefore, the activity enhancement of PtSn electrodes versus PtRu and Pt electrodes is most pronounced in pure CO and decreases with the CO concentration in CO/N{sub 2} and CO/H{sub 2} mixtures.

Gasteiger, H.A. [Univ. Ulm (Germany). Abteilung Oberflaechenchemie und Katalyse; Markovic, N.M.; Ross, P.N. Jr. [Lawrence Berkeley National Lab., CA (United States)

1997-04-01T23:59:59.000Z

180

The origins of ordering in CuPt  

Science Conference Proceedings (OSTI)

The alloy CuPt is one of the few that order into a L1{sub 1} crystal structure, i.e. planes of copper and planes of planes of planes of platinum perpendicular to the direction. For disordered CuPt, the calculated Warren-Cowley short-range order parameter indicates an instability to concentration fluctuations with a wave-vector of ({1/2}, {1/2}, {1/2}), consistent with L1{sub 1} ordering. We show that this rare tendency is due to this ordering vector arising from the large joint density of states associated with L point and X point van-Hove singularities which lie near the Fermi energy.

Clark, J.F.; Pinski, F.J. [Cincinnati Univ., OH (United States). Dept. of Physics; Sterne, P.A. [California Univ., Davis, CA (United States)]|[Lawrence Livermore National Lab., CA (United States); Johnson, D.D. [Sandia National Labs., Albuquerque, NM (United States); Staunton, J.B. [Warwick Univ., Coventry (United Kingdom). Dept. of Physics; Ginatempo, B. [Messina Univ. (Italy). Ist. di Fisica Teorica

1993-08-04T23:59:59.000Z

Note: This page contains sample records for the topic "ni pd pt" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

The origins of ordering in CuPt  

SciTech Connect

The alloy CuPt is one of the few that order into a L1{sub 1} crystal structure, i.e. planes of copper and planes of planes of planes of platinum perpendicular to the < 111 > direction. For disordered CuPt, the calculated Warren-Cowley short-range order parameter indicates an instability to concentration fluctuations with a wave-vector of ({1/2}, {1/2}, {1/2}), consistent with L1{sub 1} ordering. We show that this rare tendency is due to this ordering vector arising from the large joint density of states associated with L point and X point van-Hove singularities which lie near the Fermi energy.

Clark, J.F.; Pinski, F.J. [Cincinnati Univ., OH (United States). Dept. of Physics; Sterne, P.A. [California Univ., Davis, CA (United States)]|[Lawrence Livermore National Lab., CA (United States); Johnson, D.D. [Sandia National Labs., Albuquerque, NM (United States); Staunton, J.B. [Warwick Univ., Coventry (United Kingdom). Dept. of Physics; Ginatempo, B. [Messina Univ. (Italy). Ist. di Fisica Teorica

1993-08-04T23:59:59.000Z

182

Isopiestic Kinetics of Pd/C/DPB Composite: Temperature Dependence  

DOE Green Energy (OSTI)

In 2007, a continuation of experiments studying the uptake kinetics of a DPB getter material was conducted. In these experiments, a powder formed from ground pellets of DPB getter as currently deployed was subject to multiple hydrogenations in an isopiestic hydrogen reactor. The objective was to observe the reaction kinetics of the powdered material as a function of ambient hydrogen pressure at room temperature, with the intention of resolving key issues of the DPB reaction mechanism that could relate to its aging and capacity characteristics. The results indicated, in agreement with work performed in 2006 as part of the same project, that the likely mechanism of DPB/Hydrogen reaction occurs via the diffusion of unreacted DPB toward the catalyst surface. They also demonstrated that at a sufficiently high pressure (on the order of a few torr) of hydrogen, the reaction was vigorous enough to release sufficient heat to vaporize both the DPB getter and its hydrogenate away from the surface of the Pd catalyst at which the reaction takes place. The consequence was a premature slowing of the reaction kinetics and a drop in overall capacity. In the present work, the isopiestic reaction scheme is expanded to study the dependence of the reaction rate of this material on both hydrogen pressure and temperature. The dependence of the reaction rate on both temperature and pressure can provide both valuable clues about the reaction mechanism, as well as the activation energy of the principal reaction. The activation energy is an especially important term for purposes of doing lifetime predictions for getters under conditions of varying temperature.

Dinh, L N; Meulenberg, R; Saab, A P

2009-05-27T23:59:59.000Z

183

Consistent Data Assimilation of Isotopes: 242Pu and 105Pd  

SciTech Connect

In this annual report we illustrate the methodology of the consistent data assimilation that allows to use the information coming from integral experiments for improving the basic nuclear parameters used in cross section evaluation. A series of integral experiments are analyzed using the EMPIRE evaluated files for 242Pu and 105Pd. In particular irradiation experiments (PROFIL-1 and -2, TRAPU-1, -2 and -3) provide information about capture cross sections, and a critical configuration, COSMO, where fission spectral indexes were measured, provides information about fission cross section. The observed discrepancies between calculated and experimental results are used in conjunction with the computed sensitivity coefficients and covariance matrix for nuclear parameters in a consistent data assimilation. The results obtained by the consistent data assimilation indicate that not so large modifications on some key identified nuclear parameters allow to obtain reasonable C/E. However, for some parameters such variations are outside the range of 1 s of their initial standard deviation. This can indicate a possible conflict between differential measurements (used to calculate the initial standard deviations) and the integral measurements used in the statistical data adjustment. Moreover, an inconsistency between the C/E of two sets of irradiation experiments (PROFIL and TRAPU) is observed for 242Pu. This is the end of this project funded by the Nuclear Physics Program of the DOE Office of Science. We can indicate that a proof of principle has been demonstrated for a few isotopes for this innovative methodology. However, we are still far from having explored all the possibilities and made this methodology to be considered proved and robust. In particular many issues are worth further investigation: • Non-linear effects • Flexibility of nuclear parameters in describing cross sections • Multi-isotope consistent assimilation • Consistency between differential and integral experiments

G. Palmiotti; H. Hiruta; M. Salvatores

2012-09-01T23:59:59.000Z

184

Novel Pt/Mg(In)(Al)O catalysts for ethane and propane dehydrogenation  

Science Conference Proceedings (OSTI)

Catalysts for the dehydrogenation of light alkanes were prepared by dispersing Pt on the surface of a calcined hydrotalcite-like support containing indium, Mg(In)(Al)O. Upon reduction in H{sub 2} at temperatures above 673 K, bimetallic particles of PtIn are observed by TEM, which have an average diameter of 1 nm. Analysis of Pt LIII-edge extended X-ray absorption fine structure (EXAFS) data shows that the In content of the bimetallic particles increases with increasing bulk In/Pt ratio and reduction temperature. Pt LIII-edge X-ray absorption near edge structure (XANES) indicates that an increasing donation of electronic charge from In to Pt occurs with increasing In content in the PtIn particles. The activity and selectivity of the Pt/Mg(In)(Al)O catalysts for ethane and propane dehydrogenation reactions are strongly dependent on the bulk In/Pt ratio. For both reactants, maximum activity was achieved for a bulk In/Pt ratio of 0.48, and at this In/Pt ratio, the selectivity to alkene was nearly 100%. Coke deposition was observed after catalyst use for either ethane or propane dehydrogenation, and it was observed that the alloying of Pt with In greatly reduced the amount of coke deposited. Characterization of the deposit by Raman spectroscopy indicates that the coke is present as highly disordered graphite particles propane dehydrogenation are comparable, the effects on activity are dependent on reactant composition. Coke deposition had no effect on ethane dehydrogenation activity, but caused a loss in propane dehydrogenation activity. This difference is attributed to the greater ease with which coke produced on the surface of PtIn nanoparticles migrates to the support during ethane dehydrogenation versus propane dehydrogenation.

Sun, Pingping; Siddiqi, Georges; Vining, William C.; Chi, Miaofang; Bell, Alexis T. (UCB); (ORNL)

2011-10-28T23:59:59.000Z

185

Improvement of thermoelectric properties for half-Heusler TiNiSn by interstitial Ni defects  

SciTech Connect

We have synthesized off-stoichiometric Ti-Ni-Sn half-Heusler thermoelectrics in order to investigate the relation between randomly distributed defects and thermoelectric properties. A small change in the composition of Ti-Ni-Sn causes a remarkable change in the thermal conductivity. An excess content of Ni realizes a low thermal conductivity of 2.93 W/mK at room temperature while keeping a high power factor. The low thermal conductivity originates in the defects generated by an excess content of Ni. To investigate the detailed defect structure, we have performed first-principles calculations and compared with x ray photoemission spectroscopy measurement. Based on these analyses, we conclude that the excess Ni atoms randomly occupy the vacant sites in the half-Heusler structure, which play as phonon scattering centers, resulting in significant improvement of the figure of merit without any substitutions of expensive heavy elements, such as Zr and Hf.

Hazama, Hirofumi; Matsubara, Masato; Asahi, Ryoji [Toyota Central R and D Labs., Inc., Nagakute, Aichi 480-1192 (Japan); Takeuchi, Tsunehiro [Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan)

2011-09-15T23:59:59.000Z

186

EXAFS of carbon monoxide oxidation on supported Pt fuel cell electrocatalysts  

Science Conference Proceedings (OSTI)

The potential dependence of the extended X-ray absorption fine structure (EXAFS) obtained at the Pt L{sub III} absorption edge for a carbon supported Pt electrocatalyst exposed to carbon monoxide is presented. The data have been analyzed using the difference file method to separate the dominant contributions of the Pt neighbors from contributions to the EXAFS from the adsorbed species. The presence of adsorbed CO is clearly observed with a Pt-C distance of 1.85 {angstrom} at potentials less than 0.5 V vs. RHE. Increasing the potential above 0.5 V resulted first in the removal of the adsorbed CO and at more positive potentials, e.g., 1.05 V, in the formation of an oxide layer, as evidenced by the presence of a Pt-O coordination shell at 2.00 {angstrom}. These results demonstrate that in situ EXAFS of supported Pt electrocatalysts may be used to probe adsorbate structures.

Maniguet, S.; Mathew, R.J.; Russell, A.E.

2000-03-09T23:59:59.000Z

187

EFFECT OF PRETREATMENT ON PT-CO/C CATHODE CATALYSTS FOR THE OXYGEN-REDUCTION REACTION  

DOE Green Energy (OSTI)

Carbon supported Pt and Pt-Co electrocatalysts for the oxygen reduction reaction in low temperature fuel cells were prepared by the reduction of the metal salts with sodium borohydride and sodium formate. The effect of surface treatment with nitric acid on the carbon surface and Co on the surface of carbon prior to the deposition of Pt was studied. The catalysts where Pt was deposited on treated carbon the ORR reaction preceded more through the two electron pathway and favored peroxide production, while the fresh carbon catalysts proceeded more through the four electron pathway to complete the oxygen reduction reaction. NaCOOH reduced Pt/C catalysts showed higher activity that NaBH{sub 4} reduced Pt/C catalysts. It was determined that the Co addition has a higher impact on catalyst activity and active surface area when used with NaBH{sub 4} as reducing agent as compared to NaCOOH.

Fox, E.; Colon-Mercado, H.

2010-01-19T23:59:59.000Z

188

Columnar grain growth of FePt(L1{sub 0}) thin films  

SciTech Connect

An experimental approach for obtaining perpendicular FePt-SiOx thin films with a large height to diameter ratio FePt(L1{sub 0}) columnar grains is presented in this work. The microstructure for FePt-SiOx composite thin films as a function of oxide volume fraction, substrate temperature, and film thickness is studied by plan view and cross section TEM. The relations between processing, microstructure, epitaxial texture, and magnetic properties are discussed. By tuning the thickness of the magnetic layer and the volume fraction of oxide in the film at a sputtering temperature of 410 deg. C, a 16 nm thick perpendicular FePt film with {approx}8 nm diameter of FePt grains was obtained. The height to diameter ratio of the FePt grains was as large as 2. Ordering at lower temperature can be achieved by introducing a Ag sacrificial layer.

Yang En; Ho Hoan [Data Storage Systems Center, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States); Laughlin, David E. [Data Storage Systems Center, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States); ALCOA Professor of Physical Metallurgy, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States); Zhu Jiangang [Data Storage Systems Center, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States); ABB Professor of Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States)

2012-04-01T23:59:59.000Z

189

Adsorption studies of gases on Pt-Rh bimetallic catalysts by reversed-flow gas chromatography  

SciTech Connect

In the present work, the relatively new technique of reversed-flow gas chromatography was applied for the study of adsorption of carbon monoxide, oxygen, and carbon dioxide on Pt-Rh bimetallic catalysts. Using suitable mathematical analysis, equations were derived by means of which rate constants for adsorption, desorption, and disproportionation reaction were calculated. From the variation of these rate constants with temperature and the nature of the catalyst (Pt content), as well as from the finding that the CO adsorption is a dissociative process, useful conclusions concerning the mechanism for the CO oxidation reaction over Pt-Rh bimetallic catalysts were extracted. The catalytic fractional conversions for the CO disproportionation reaction were found to be higher for the Pt-RH bimetallic catalysts than those for the pure Pt catalyst, indicating the presence of beneficial Pt-Rh synergism.

Gavril, D.; Koliadima, A.; Karaiskakis, G. [Univ. of Patras (Greece). Dept. of Chemistry

1999-05-25T23:59:59.000Z

190

Security Testing Tool for End-User Devices (PT2) Version 1.0  

Science Conference Proceedings (OSTI)

The Penetration Testing Toolkit is a software tool to aid end users in the security assessment of power systems sector specific embedded devices.  The PT2 provides the end user with a centralized interface for managing and executing penetration test activities.  The PT2 gives the end user the ability to execute the full range of penetration test activities such as: script execution, data collection, data analysis, traffic injection, and fuzzing.  Additionally, the PT2 provides access ...

2012-11-29T23:59:59.000Z

191

Airtricity Developments NI Ltd | Open Energy Information  

Open Energy Info (EERE)

NI Ltd NI Ltd Jump to: navigation, search Name Airtricity Developments NI Ltd Place Belfast, Northern Ireland, United Kingdom Zip BT2 7AF Sector Wind energy Product Focused on construction of wind farms in Northern Ireland. Coordinates 54.595295°, -5.934524° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":54.595295,"lon":-5.934524,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}

192

Carbon Nanotube Growth Using Ni Catalyst in Different Layouts  

E-Print Network (OSTI)

Vertically aligned carbon nanotubes have been grown using Ni as catalyst by plasma enhanced chemical vapor deposition system (PECVD) in various pre-patterned substrates. Ni was thermally evaporated on silicon substrates ...

Nguyen, H. Q.

193

Novel and NiTi-based Shape Memory Alloys  

Science Conference Proceedings (OSTI)

Mar 4, 2013 ... Phase Constitution, Mechanical and Shape Memory Properties of (Pt,Co)Ti Alloys: Hideki Hosoda1; Satoshi Tsutsumi1; Masaki Tahara1; ...

194

Description of the shape evolution in the yrast states of 186Pt  

E-Print Network (OSTI)

186Pt was tested in the framework of IBM-1 and the X(3) model. The results show that 186Pt is located close to the shape phase transition point, but the B(E2) values little agree with the X(3) model. The shape evolution in the yrast states of 186Pt is also discussed in detail. TRS calculation exhibits a at bottomed potential at low spin states, but a relatively deep minimum at high spin states. It suggests that a shape evolution from vibrational mode to rotational mode happens in 186Pt. The result is in agreement with the E-GOS calculation.

Chuang-Ye, He; Yun, Zheng; Cong-Bo, Li

2013-01-01T23:59:59.000Z

195

Description of the shape evolution in the yrast states of 186Pt  

E-Print Network (OSTI)

186Pt was tested in the framework of IBM-1 and the X(3) model. The results show that 186Pt is located close to the shape phase transition point, but the B(E2) values little agree with the X(3) model. The shape evolution in the yrast states of 186Pt is also discussed in detail. TRS calculation exhibits a at bottomed potential at low spin states, but a relatively deep minimum at high spin states. It suggests that a shape evolution from vibrational mode to rotational mode happens in 186Pt. The result is in agreement with the E-GOS calculation.

He Chuang-Ye; Wu Xiao-Guang; Zheng Yun; Li Cong-Bo

2013-09-25T23:59:59.000Z

196

Ni spin switching induced by magnetic frustration in FeMn/Ni/Cu(001)  

SciTech Connect

Epitaxially grown FeMn/Ni/Cu(001) films are investigated by Photoemission Electron Microscopy and Magneto-Optic Kerr Effect. We find that as the FeMn overlayer changes from paramagnetic to antiferromagnetic state, it could switch the ferromagnetic Ni spin direction from out-of-plane to in-plane direction of the film. This phenomenon reveals a new mechanism of creating magnetic anisotropy and is attributed to the out-of-plane spin frustration at the FeMn-Ni interface.

Wu, J.; Choi, J.; Scholl, A.; Doran, A.; Arenholz, E.; Hwang, Chanyong; Qiu, Z. Q.

2009-03-08T23:59:59.000Z

197

CO Oxidation on supported single Pt atoms - Experimental and Ab Initio density functional studies of CO interaction with Pt atom on theta-alumina(010) surface  

Science Conference Proceedings (OSTI)

Although there are only a few known examples of supported single atoms, they are unique because they bridge the gap between homogenous and heterogeneous catalysis. The metal center is single supported atoms can be isoelectronic with their homogenous catalyst counterpart and may allow mechanistic pathways normally seen in homogenous catalysts. Here, we report CO oxidation activity of mono-disperse single Pt atoms supported on an inert substrate, -alumina (Al2O3), in the presence of stoichiometric oxygen. Since CO oxidation on single Pt atoms cannot occur via a conventional Langmuir-Hinshelwood scheme (L-H scheme) which requires at least one Pt-Pt bond, we have carried out a first principles density functional theoretical study of a proposed pathway which is a variation on the conventional L-H scheme and is inspired by organometallic chemistry of platinum. We find that a single supported Pt atom prefers to bond to O2 over CO. The CO then bonds with the oxygenated Pt atom and forms a carbonate which dissociates to liberate CO2, leaving an oxygen atom on Pt. A subsequent reaction with another CO molecule regenerates the single atom catalyst. An in-situ diffuse reflectance infrared study of CO adsorption on the catalyst s supported single atoms has been carried out to infer information on CO absorption modes and compare the observed spectra with calculated ones for intermediates in the proposed CO oxidation pathway. Our results clearly show that supported Pt single atoms are catalytically active and that this catalytic activity can occur without involving the substrate. Characterization by electron microscopy and X-ray absorption studies of the mono-disperse Pt/ -Al2O3, synthesized by solution methods, are also presented.

Narula, Chaitanya Kumar [ORNL; Debusk, Melanie Moses [ORNL; Yoon, Mina [ORNL; Allard Jr, Lawrence Frederick [ORNL; Mullins, David R [ORNL; Wu, Zili [ORNL; Yang, Xiaofan [ORNL; Veith, Gabriel M [ORNL; Stocks, George Malcolm [ORNL

2013-01-01T23:59:59.000Z

198

Cu-Pd Hydrogen Separation Membranes with Reduced Palladium Content and Improved Performance  

NLE Websites -- All DOE Office Websites (Extended Search)

Cu-Pd Hydrogen Separation Membranes with Reduced Cu-Pd Hydrogen Separation Membranes with Reduced Palladium Content and Improved Performance Opportunity This patent-pending technology, "Cu-Pd Hydrogen Separation Membranes with Reduced Palladium Content and Improved Performance," consists of copper-palladium alloy compositions for hydrogen separation membranes that use less palladium and have a potential increase in hydrogen permeability and resistance to sulfur degradation compared to currently available copper-palladium membranes. This technology is available for licensing and/or further collaborative research with the U.S. Department of Energy's National Energy Technology Laboratory. Overview NETL is working to help produce and deliver hydrogen from fossil fuels including coal in commercially applicable and environmentally

199

Segregation at CuxPd1-x alloy hydrogen purification membranes  

Science Conference Proceedings (OSTI)

CuxPd1-x alloy membranes have exhibited sulfur tolerance in their application as hydrogen purification membranes. The surfaces of such membranes are known to have compositions that differ from those of the bulk and furthermore, compositions that vary with environment. XPS, LEIS and hydrogen adsorption have been used to characterize the surfaces of a Cu30Pd70 membrane over temperatures ranging from 300 – 1000 K. On timescales of ~1 hour, the surface is found to equilibrate with the near surface region at all temperatures above 300 K but is only equilibrated with the bulk at temperatures in excess of 800 K. The clean alloy surface is Cu rich, but once modified by the adsorption of sulfur the surface exposes only Pd.

Gellman, A.J.; Ye, P.; Miller, J.B.; Matranga, C.S.

2007-03-01T23:59:59.000Z

200

Magnetoelastic Coupling in NiMnGa Ferromagnetic Shape ...  

Science Conference Proceedings (OSTI)

... Magnetoelastic Coupling in NiMnGa Ferromagnetic Shape Memory Alloys. Peng Zhao (Dept. of Materials Science and ...

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201

High Temperature coatings based on {beta}-NiAI  

Science Conference Proceedings (OSTI)

High temperature alloys are reviewed, focusing on current superalloys and their coatings. The synthesis, characerization, and oxidation performance of a NiAl–TiB{sub 2} composite are explained. A novel coating process for Mo–Ni–Al alloys for improved oxidation performance is examined. The cyclic oxidation performance of coated and uncoated Mo–Ni–Al alloys is discussed.

Severs, Kevin

2012-07-10T23:59:59.000Z

202

Upper limits to fusion rates of isotopic hydrogen molecules in Pd  

SciTech Connect

We have calculated upper bounds for {ital p}-{ital d} and {ital d}-{ital d} fusion rates at octahedral and tetrahedral sites in saturated PdH. Our molecular potentials include Thomas-Fermi screening for two centers and realistic Pd crystal potentials. Accurate numerical techniques were used to solve for radial wave functions down to {ital r}=0. From these wave functions we find rates that are considerably enhanced over those for the free molecules, but 10--20 orders of magnitude lower than the claims of early experiments.

Alberg, M.A. (Department of Physics, Seattle University, Seattle, Washington 98122 (USA) Department of Physics, Institute for Nuclear Theory, FM-15, University of Washington, Seattle, Washington 98195, (USA)); Wilets, L. (Department of Physics, University of Washington, Seattle, Washington 98195, (USA) Institute for Nuclear Theory, FM-15, University of Washington, Seattle, Washington 98195, (USA)); Rehr, J.J.; Mustre de Leon, J. (Department of Physics, FM-15, University of Washington, Seattle, Washington 98195, (USA))

1990-06-01T23:59:59.000Z

203

Heterogeneous Catalysis on Atomically Dispersed Supported Metals: CO2 Reduction on Multifunctional Pd Catalysts  

Science Conference Proceedings (OSTI)

Temperature programmed reaction and scanning transmission electron microscopy experiments were applied to prove the requirement of two different catalyst functionalities for the reduction of CO2 with hydrogen on Pd/Al2O3 and Pd/MWCNT catalysts. The research described in this paper was supported by the Laboratory Directed Research and Development (LDRD) program of the Pacific Northwest National Laboratory (PNNL) and was performed at the Environmental Molecular Sciences Laboratory (EMSL), a national scientific user facility sponsored by the DOE’s Office of Biological and Environmental Research and located at PNNL. PNNL is operated for the US DOE by Battelle Memorial Institute.

Kwak, Ja Hun; Kovarik, Libor; Szanyi, Janos

2013-11-01T23:59:59.000Z

204

Exactly solvable PT-symmetric Hamiltonian having no Hermitian counterpart  

E-Print Network (OSTI)

In a recent paper Bender and Mannheim showed that the unequal-frequency fourth-order derivative Pais-Uhlenbeck oscillator model has a realization in which the energy eigenvalues are real and bounded below, the Hilbert-space inner product is positive definite, and time evolution is unitary. Central to that analysis was the recognition that the Hamiltonian $H_{\\rm PU}$ of the model is PT symmetric. This Hamiltonian was mapped to a conventional Dirac-Hermitian Hamiltonian via a similarity transformation whose form was found exactly. The present paper explores the equal-frequency limit of the same model. It is shown that in this limit the similarity transform that was used for the unequal-frequency case becomes singular and that $H_{\\rm PU}$ becomes a Jordan-block operator, which is nondiagonalizable and has fewer energy eigenstates than eigenvalues. Such a Hamiltonian has no Hermitian counterpart. Thus, the equal-frequency PT theory emerges as a distinct realization of quantum mechanics. The quantum mechanics associated with this Jordan-block Hamiltonian can be treated exactly. It is shown that the Hilbert space is complete with a set of nonstationary solutions to the Schr\\"odinger equation replacing the missing stationary ones. These nonstationary states are needed to establish that the Jordan-block Hamiltonian of the equal-frequency Pais-Uhlenbeck model generates unitary time evolution.

Carl M. Bender; Philip D. Mannheim

2008-04-25T23:59:59.000Z

205

Isonitrile radionuclide complexes for labelling and imaging agents  

DOE Patents (OSTI)

A coordination complex of an isonitrile ligand and radionuclide such as Tc, Ru, Co, Pt, Fe, Os, Ir, W, Re, Cr, Mo, Mn, Ni, Rh, Pd, Nb and Ta, is useful as a diagnostic agent for labelling liposomes or vesicles, and selected living cells containing lipid membranes, such as blood clots, myocardial tissue, gall bladder tissue, etc.

Jones, Alun G. (Newton Centre, MA); Davison, Alan (Needham, MA); Abrams, Michael J. (Allston, MA)

1984-06-04T23:59:59.000Z

206

Measurement of {sup 63}Ni and {sup 59}Ni by accelerator mass spectrometry using characteristic projectile x-rays  

Science Conference Proceedings (OSTI)

The long-lived isotopes of nickel ({sup 59}Ni, {sup 63}Ni) have current and potential use in a number of applications including cosmic radiation studies, biomedical tracing, characterization of low-level radioactive wastes, and neutron dosimetry. Methods are being developed at LLNL for the routine detection of these isotopes by AMS. One intended application is in Hiroshima dosimetry. The reaction {sup 63}Cu(n,p){sup 63}Ni has been identified as one of a small number of reactions which might be used for the direct determination of the fast neutron fluence emitted by the Hiroshima bomb. AMS measurement of {sup 63}Ni(t{sub 1/2} = 100 y) requires the chemical removal of {sup 63}Cu, which is a stable isobar of {sup 63}Ni. Following the electrochemical separation of Ni from gram-sized copper samples, the Cu concentration is further lowered to Hiroshima hypocenter. For the demonstration samples, the Cu content was chemically reduced by a factor of 10{sup 12} with quantitative retention of {sup 63}Ni. Detection sensitivity (3{sigma}) was {approximately}20 fg {sup 63}Ni in 1 mg Ni carrier ({sup 63}Ni/Ni {approx} 2 x 10{sup -11}). Significant improvements in sensitivity are expected with planned incremental changes in the methods. Preliminary results indicate that a similar sensitivity is achievable for {sup 59}Ni (t{sub 1/2} = 10{sup 5} y).

McAninch, J.E.; Hainsworth, L.J.; Marchetti, A.A. [and others

1996-05-01T23:59:59.000Z

207

Kinetics of chemical ordering in a Ag-Pt nanoalloy particle via first-principles simulations  

SciTech Connect

The energetics and kinetic energy barriers of vacancy/atom exchange in a 37-atom truncated octahedron Ag-Pt binary cluster in the Ag-rich range of compositions are investigated via a first-principles atomistic approach. The energy of the local minima obtained considering various distributions of a single vacancy and a few Pt atoms within the cluster and the energy barriers connecting them are evaluated using accurate density-functional calculations. The effects of the simultaneous presence of a vacancy and Pt atoms are found to be simply additive when their distances are larger than first-neighbors, whereas when they can be stabilizing at low Pt content due to the release of strain by the Pt/vacancy interaction or destabilizing close to a perfect Pt(core)/Ag(shell) arrangement. It is found that alloying with Pt appreciably increases the barriers for homotops transformations, thus rationalizing the issues encountered at the experimental level in producing Ag-Pt equilibrated nanoparticles and bulk phase diagram.

Negreiros, F. R.; Fortunelli, A. [CNR-IPCF, Istituto per i Processi Chimico-Fisici del Consiglio Nazionale delle Ricerche, Molecular Modeling Laboratory, via G. Moruzzi 1, Pisa I56124 (Italy); Taherkhani, F. [Department of Chemistry, Razi University, Kermanshah (Iran, Islamic Republic of); Parsafar, G. [Department of Chemistry and Nanotechnology Center, Sharif University of Technology, Tehran (Iran, Islamic Republic of); Caro, A. [Los Alamos National Laboratories, Division of Materials Science and Technology, Los Alamos, New Mexico 87545 (United States)

2012-11-21T23:59:59.000Z

208

CO adsorption on Ce-Pt(111) studied with LEED, XPS, and temperature programmed desorption  

Science Conference Proceedings (OSTI)

CO adsorption on Ce-Pt(111) has been studied by temperature programmed desorption (TPD), low energy electron diffraction (LEED) and x-ray photoelectron spectroscopy (XPS). Thin layers (1 to 3 ML) of Ce on Pt(111) form upon annealing to 1000 K a surface alloy which most likely is Pt terminated. The CO overlayer structure on Ce-Pt(111) at saturation coverage is argued to be an intermediate between (2x2) and c(4x2) superstructures. This intermediate structure exhibits a c(4x2) LEED pattern in which some of the spots appear together as ordered triangles. The thermal desorption spectra for the Ce-Pt(111) surface alloy are shifted down by a temperature of about 120 K compared to the CO desorption of pure Pt(111), most likely due to a change in the d-band due to hybridization between Ce and Pt states, which results in a weakening of the resonant interaction between CO 5{sigma} and Pt 5d states.

Vermang, B.; Juel, M.; Raaen, S. [Physics Department, Norwegian University of Science and Technology, N-7491 Trondheim (Norway)

2006-01-15T23:59:59.000Z

209

A carbon riveted Pt/Graphene catalyst with high stability for direct methanol fuel cell  

Science Conference Proceedings (OSTI)

Pt/Graphene catalyst was prepared by microwave-assisted polyol process, and carbonization was riveted onto the catalyst surface to enhance the catalyst stability. The physical properties of the obtained catalysts were characterized by X-ray diffraction ... Keywords: Direct methanol fuel cell, Methanol electrooxidation, Pt/Graphene, Stability

Xiaowei Liu, Jialin Duan, Hailong Chen, Yufeng Zhang, Xuelin Zhang

2013-10-01T23:59:59.000Z

210

Comparison of Three Ni-Hard I Alloys  

Office of Scientific and Technical Information (OSTI)

Comparison of Three Ni-Hard I Alloys Comparison of Three Ni-Hard I Alloys Ö. N. Do-an 1 , J.A. Hawk 1 , and J.Rice 2 1 U.S. Department of Energy, Albany Research Center, Albany, Oregon 2 Texaloy Foundry Co., Inc., Floresville, Texas Keywords: Ni-Hard white irons, Bainite, Martensite, Austenite, Abrasion resistant iron Abstract This report documents the results of an investigation which was undertaken to reveal the similarities and differences in the mechanical properties and microstructural characteristics of three Ni-Hard I alloys. One alloy (B1) is ASTM A532 class IA Ni-Hard containing 4.2 wt. pct. Ni. The second alloy (B2) is similar to B1 but higher in Cr, Si, and Mo. The third alloy (T1) also falls in the same ASTM specification, but it contains 3.3 wt. pct. Ni. The alloys were evaluated in both as-cast and

211

Synthesis and characterization of T[Ni(CN){sub 4}].2pyz with T=Fe, Ni; pyz=pyrazine: Formation of T-pyz-Ni bridges  

Science Conference Proceedings (OSTI)

The formation of T-pyz-Ni bridges (pyz=pyrazine) in the T[Ni(CN){sub 4}].2pyz series is known for T=Mn, Zn, Cd and Co but not with T=Fe, Ni. In this contribution the existence of such bridges also for T=Fe, Ni is discussed. The obtained pillared solids, T[Ni(CN){sub 4}].2pyz, were characterized from XRD, TG, UV-Vis, IR, Raman, Moessbauer and magnetic data. Their crystal structures were refined in the orthorhombic Pmna space group from XRD powder patterns. The structural behavior of these solids on cooling down to 77 K was also studied. In the 180-200 K temperature range the occurrence of a structural transition to a monoclinic structure (P2{sub 1}/c space group) was observed. No temperature induced spin transition was observed for Fe[Ni(CN){sub 4}].2pyz. The iron (II) was found to be in high spin electronic state and this configuration is preserved on cooling down to 2 K. The magnetic data indicate the occurrence of a low temperature weak anti-ferromagnetic interaction between T metal centers within the T[Ni(CN){sub 4}] layer. In the paramagnetic region for Ni[Ni(CN){sub 4}].2pyz, a reversible temperature induced spin transition for the inner Ni atom was detected. - Graphical abstract: Rippled sheets structure for the pillared solids T[Ni(CN){sub 4}].2pyz. The pyrazine molecule is found forming T-pyz-Ni bridges between neighboring layers. Highlights: > Pillared 2D solids. > Inorganic-organic solids. > Assembling of molecular blocks. > From 1D and 2D building blocks to 3D solids.

Lemus-Santana, A.A. [Center for Applied Science and Advanced Technology, Legaria Unit, National Polytechnic Institute of Mexico, Mexico D.F. (Mexico); Rodriguez-Hernandez, J. [Center for Applied Science and Advanced Technology, Legaria Unit, National Polytechnic Institute of Mexico, Mexico D.F. (Mexico); Institute of Materials Science and Technology, University of Havana (Cuba); Gonzalez, M. [Center for Applied Science and Advanced Technology, Legaria Unit, National Polytechnic Institute of Mexico, Mexico D.F. (Mexico); Demeshko, S. [Institut fuer Anorganische Chemie, Georg-August-Universitaet Goettingen, Tammannstrasse 4, 37077 Goettingen (Germany); Avila, M. [Center for Applied Science and Advanced Technology, Legaria Unit, National Polytechnic Institute of Mexico, Mexico D.F. (Mexico); Knobel, M. [Institute of Physics 'Gleb Wataghin', UNICAMP, 13083-970 Campinas, SP (Brazil); Reguera, E., E-mail: ereguera@yahoo.com [Center for Applied Science and Advanced Technology, Legaria Unit, National Polytechnic Institute of Mexico, Mexico D.F. (Mexico)

2011-08-15T23:59:59.000Z

212

From PD to Nonlinear Adaptive Depth-Control of a Tethered Autonomous Underwater Vehicle  

E-Print Network (OSTI)

From PD to Nonlinear Adaptive Depth-Control of a Tethered Autonomous Underwater Vehicle D and an adaptive nonlinear state feedback one, both applied on a tethered autonomous underwater vehicle. The aim performed using each of the above mentioned control laws. Keywords: Underwater robotics, Depth control

Paris-Sud XI, Université de

213

Experimental Astrophysical Reaction Rates of Threshold (p,n)-Reactions on Pd Isotopes  

SciTech Connect

Astrophysical S-factors for (p,n) reactions on stable Pd isotopes derived from experimental cross sections were compared to statistical model predictions with the NON-SMOKER code. Satisfactory agreement was found. Reaction rates were derived by combining experiment and theory.

Skakun, Ye. [Kharkiv Institute of Physics and Technology, Academicheskaja str., 1, 61108 Kharkiv (Ukraine); Rauscher, T. [Departement fuer Physik, Universitaet Basel, Klingelbergstr, 82, CH-4056 Basel (Switzerland)

2008-05-21T23:59:59.000Z

214

Electrochemical and neutron diffraction measurements of PdD{sub x} cathodes  

DOE Green Energy (OSTI)

Potentiometric and in-situ neutron diffraction measurements have been carried out on PdD{sub x} cathodes in LiOD-saturated D{sub 2}O solution. Open-circuit potentials of the PdD{sub x} electrode after interruption of high-intensity cathodic currents (300--500 mA/cm{sup 2}) showed a more negative potential ({epsilon} = 1010 mV, measured against a Hg/HgO reference electrode) than that expected from the literature. The anomalous potentials were observed for about 10--20 min after current interruption at x > 0.7 concentrations of deuterium. This phenomenon may indicate a metastable phase of the Pd-D system, which may be detected by neutron diffraction. In-situ neutron diffraction measurements, so far, have indicated only the evolution of the known {alpha} and {beta} phases of PdD{sub x}. Successful neutron diffraction measurements in electrochemical cells suggest the viability of this technique for in-situ investigations of metal-hydride battery electrodes in experiments when heavy-water electrolyte is used to model the MH{sub 2}/H{sub 2}O electrode.

Redey, L.; Myles, K.M.; Rotella, F.J.; Richardson, J.W. Jr.; Felcher, G.P.; Hitterman, R.L.; Kleb, R.

1991-12-31T23:59:59.000Z

215

CO2 + CH4 Chemistry over Pd: Results of Kinetic Simulations Relevant to  

E-Print Network (OSTI)

hydrogen (methane is `reformed' to synthesis gas or `syngas'). Rezaei et al. [3] reported the production of syngas by methane reforming on a number of transition metal surfaces. They attribute the relatively low efficacy of Pd for the syngas production by methane reforming to carbon deposits on the surface

Spiteri, Raymond J.

216

Adaptation of P.D. Thompson's Scheme to the Constraint of Potential vorticity Conservation  

Science Conference Proceedings (OSTI)

The dynamical adjustment scheme of P.D. Thompson (1969) has been adapted to the two-parameter baroclinic model which has potential vorticity as the constraint. In contrast to Thompson's approach, which used a differential-difference form of the ...

John M. Lewis

1982-11-01T23:59:59.000Z

217

ADSORPTION AND BONDING OF BUTANE AND PENTANE ON THE Pt(111) CRYSTAL SURFACES. EFFECTS OF OXYGEN TREATMENTS AND DEUTERIUM PREADSORPTION  

E-Print Network (OSTI)

ADSORPTION AND BONDING OF BUTANE AND PENTANE ON THE .Pt(111)ADSORPTION AND BONDING OF BUTANE AND PENTANE ON THE Pt(lll)adsorption characteristics of butane and pentane on the (

Salmeron, M.

2012-01-01T23:59:59.000Z

218

FePt-based exchange-coupled composite perpendicular recording media.  

Science Conference Proceedings (OSTI)

In order to demonstrate the strong and proper exchange coupling between bottom magnetic layer and capping magnetic layer in FePt-based exchange-coupled composite (ECC) perpendicular recording media, we have investigated the thermal stability, writability, degree of exchange coupling, and ECC gain factor of FePt-based ECC media as a function of the thickness of the capping FePt layer. With increasing the thickness of capping FePt layer, both thermal stability and media writability increase simultaneously as a result of the change from strong exchange coupling to proper exchange coupling. The proper exchange-coupled FePt ECC is a promising candidate for future high-density perpendicular recording.

Sun, C.; Stafford, D.; Acharya, R.; X-Ray Science Division; Western Digital Media

2010-06-01T23:59:59.000Z

219

Stripe-to-bubble transition of magnetic domains at the spin reorientation of (Fe/Ni)/Cu/Ni/Cu(001)  

Science Conference Proceedings (OSTI)

Magnetic domain evolution at the spin reorientation transition (SRT) of (Fe/Ni)/Cu/Ni/Cu(001) is investigated using photoemission electron microscopy. While the (Fe/Ni) layer exhibits the SRT, the interlayer coupling of the perpendicularly magnetized Ni layer to the (Fe/Ni) layer serves as a virtual perpendicular magnetic field exerted on the (Fe/Ni) layer. We find that the perpendicular virtual magnetic field breaks the up-down symmetry of the (Fe/Ni) stripe domains to induce a net magnetization in the normal direction of the film. Moreover, as the virtual magnetic field increases to exceed a critical field, the stripe domain phase evolves into a bubble domain phase. Although the critical field depends on the Fe film thickness, we show that the area fraction of the minority domain exhibits a universal value that determines the stripe-to-bubble phase transition.

Wu, J.; Choi, J.; Won, C.; Wu, Y. Z.; Scholl, A.; Doran, A.; Hwang, Chanyong; Qiu, Z.

2010-06-09T23:59:59.000Z

220

High-$\\pt$ processes measured with ALICE at the LHC  

E-Print Network (OSTI)

The study of single-particle and jet production in heavy-ion collisions provides insights into the density of the medium and the energy-loss mechanisms. The observed suppression of high-$\\pt$ particle production is generally attributed to energy loss of partons as they propagate through the hot and dense QCD medium - Quark-Gluon-Plasma (QGP). Such measurements allow the characterization of the QGP, the deconfined state of quarks and gluons, predicted by QCD. In these proceedings we present the analysis results of Pb--Pb collisions at $\\sqrt{\\sNN}=2.76$ TeV recorded by ALICE. The nuclear modification factors ($\\RAA$) and the results from jet reconstruction in Pb--Pb are presented. Comparison with other measurements and with theory models is discussed.

Jacek Otwinowski; for the ALICE Collaboration

2013-01-22T23:59:59.000Z

Note: This page contains sample records for the topic "ni pd pt" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

HYDROGEN CHEMISORPTION ON Pt SINGLE CRYSTAL SURFACES IN ACIDIC SOLUTIONS  

DOE Green Energy (OSTI)

Hydrogen chemisorption from dilute acidic solution onto Pt single crystal surfaces was examined using an electrochemical cell directly coupled to LEED/Auger analytical system. No pre-anodization was used prior to observing hydrogen adsorption by cyclic voltammetry so that clean surfaces having the ordered structures indicated by LEED were studied. The problem of contributions from non-ordered parts of the electrode like support wires and edges was solved by using a gold evaporation masking technique. The specific contribution of atomic imperfections to the voltammetry curve was deduced from the ordered and countable imperfections occurring on high Miller index single crystal surfaces that have a stepped structure. The H-Pt bond energy Has found to be structure sensitive, and sensitive both to local site geometry and long range order in the surface. The bond strength was found to vary systematically: n(111)x(100) > (100) > n(111)x(111) > (110) > (111). Distinct states for hydrogen at steps versus hydrogen on terraces could be distinguished. The (110) surface is shown to be a (111) vicinal, probably the [3(111) x 2(111)] microfacetted surface. The zero coverage heat of adsorption on the well-ordered (111) surface (48 kJ/mol) in solutions is the same as the value reported by Ertl and co-workers for adsorption on a (111) surface in vacuum. Adsorption Isotherms for hydrogen on the (111) and (100) surfaces is adequately fit by the classical model for immobile adsorption at single sites with nearest neighbor repulsive interaction.

Ross, Jr., Philip N.

1980-04-01T23:59:59.000Z

222

SF 6432-NI (04-95)  

NLE Websites -- All DOE Office Websites (Extended Search)

6/14/11 6/14/11 Page 1 of 14 Printed copies of this document are uncontrolled. Retrieve latest version electronically. SF 6432-NI (06/14/11) SECTION II STANDARD TERMS AND CONDITIONS FOR FIXED PRICE CONTRACTS WITH THE NEWLY INDEPENDENT STATES OF THE FORMER SOVIET UNION INDEX OF CLAUSES. THE FOLLOWING CLAUSES APPLY TO REQUESTS FOR QUOTATION AND CONTRACTS AS INDICATED UNLESS SPECIFICALLY DELETED, OR EXCEPT TO THE EXTENT THEY ARE SPECIFICALLY SUPPLEMENTED OR AMENDED IN WRITING IN THE SIGNATURE PAGE OR SECTION I. NI01 - ACCEPTANCE OF TERMS AND CONDITIONS Contractor, by signing this Agreement, beginning performance, and/or delivering Items or services ordered under this Agreement, agrees to comply with all the terms and conditions and all specifications and other documents that this Contract incorporated by

223

Microsoft Word - NiR.doc  

NLE Websites -- All DOE Office Websites (Extended Search)

Side-on Cu-Nitrosyl Coordination by Nitrite Reductase Side-on Cu-Nitrosyl Coordination by Nitrite Reductase Elitza I. Tocheva and Michael E. P. Murphy Department of Microbiology & Immunology, The University of British Columbia, Vancouver, BC, Canada V6T 1Z3. Nitric oxide (NO) is one of the smallest and simplest biologically active molecules. In mammals, NO is produced from arginine by isoforms of nitric oxide synthase, and it func- tions in signal transduction and as a cytoprotective or cytotoxic agent. In bacteria, NO is produced by nitrite reductase (NiR), a copper-containing enzyme, which is responsible for the reduction of nitrite to nitric oxide (NO) in the process of dissimilatory denitrification. Cu- containing NiRs are homotrimers with two distinct Cu sites per monomeric unit (1). The type

224

Cross sections for proton-induced reactions on Pd isotopes at energies relevant for the {gamma} process  

Science Conference Proceedings (OSTI)

Proton-activation reactions on natural and enriched palladium samples were investigated via the activation technique in the energy range of E{sub p}=2.75-9 MeV, close to the upper end of the respective Gamow window of the {gamma} process. We have determined cross sections for {sup 102}Pd(p, {gamma}){sup 103}Ag, {sup 104}Pd(p, {gamma}){sup 105}Ag, and {sup 105}Pd(p, n){sup 105}Ag, as well as partial cross sections of {sup 104}Pd(p, n){sup 104}Ag{sup g}, {sup 105}Pd(p, {gamma}){sup 106}Ag{sup m}, {sup 106}Pd(p, n){sup 106}Ag{sup m}, and {sup 110}Pd(p, n){sup 110}Ag{sup m} with uncertainties between 3% and 15% for constraining theoretical Hauser-Feshbach rates and for direct use in {gamma}-process calculations.

Dillmann, I.; Coquard, L.; Domingo-Pardo, C.; Kaeppeler, F.; Marganiec, J.; Uberseder, E.; Giesen, U.; Heiske, A.; Feinberg, G.; Hentschel, D.; Hilpp, S.; Leiste, H.; Rauscher, T.; Thielemann, F.-K. [Karlsruher Institut fuer Technologie (KIT), Campus Nord, Institut fuer Kernphysik, Postfach 3640, D-76021 Karlsruhe (Germany); Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, D-38116 Braunschweig (Germany); Soreq Nuclear Research Center, Yavne (Israel); Karlsruher Institut fuer Technologie (KIT), Campus Nord, Institut fuer Nukleare Entsorgung, Postfach 3640, D-76021 Karlsruhe (Germany); Karlsruher Institut fuer Technologie (KIT), Campus Nord, Institut fuer Angewandte Materialien, Postfach 3640, D-76021 Karlsruhe (Germany); Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel (Switzerland)

2011-07-15T23:59:59.000Z

225

C?H Bond Activation by Pd-substituted CeO[subscript 2]: Substituted Ions versus Reduced Species  

Science Conference Proceedings (OSTI)

Substituted metal oxides containing ionic species have been attracting a great deal of attention because of their potential ability to reduce the usage of precious metals in heterogeneous catalysts. We investigate Pd-substituted CeO{sub 2} for C-H bond activation reactions including the partial oxidation and dry reforming of CH{sub 4}. This catalyst has been previously studied for CO oxidation, NO{sub x} reduction, and the water-gas shift reaction. Pd-substituted CeO{sub 2}, Ce{sub 1-x}Pd{sub x}O{sub 2-{delta}}, was prepared as a powder with high surface area and a hollow sphere morphology using ultrasonic spray pyrolysis. The catalysts were extensively characterized using synchrotron X-ray diffraction and other techniques, confirming phase pure samples up to 10 mol % Pd substitution. Ce{sub 0.95}Pd{sub 0.05}O{sub 2-{delta}} was found to be active for partial oxidation of CH{sub 4} around 500 C and higher. Our studies, including postcatalytic synchrotron diffraction, suggest that the single-phase Ce{sub 1-x}Pd{sub x}O{sub 2-{delta}} material is not the active species and that catalysis occurs instead over the reduced two-phase Pd{sup 0}/CeO{sub 2}. This observation has been further confirmed by verifying the activity of the reduced Pd{sup 0}/CeO{sub 2} catalysts for ethylene hydrogenation, a reaction that is known to require Pd{sup 0}.

Misch, Lauren M.; Kurzman, Joshua A.; Derk, Alan R.; Kim, Young-Il; Seshadri, Ram; Metiu, Horia; McFarland, Eric W.; Stucky, Galen D. (Yeungnam); (UCSB)

2012-02-07T23:59:59.000Z

226

Size Influence on the Oxygen Reduction Reaction Activity and Instability of Supported Pt Nanoparticles  

DOE Green Energy (OSTI)

Size-dependent oxygen reduction reaction activity (ORR) and instability of Pt nanoparticles is of great importance in proton exchange membrane fuel cell applications. In this study, the size-dependence of ORR activity on Pt nanoparticles (NPs) was investigated on high-surface-area carbon supported Pt NPs below 5 nm in acidic electrolytes using rotating disk electrode method. The ORR activity was correlated to the estimated surface coverage by OH anion from cyclic voltammogram measurements and the surface composition and electronic structure of Pt NPs, which was studied using X-ray photoemission spectroscopy, and ultraviolet photoemission spectroscopy. The results revealed a size-independent ORR activity on Pt NPs below 5 nm, which was attributed to similar surface compositions and surface electronic structures of Pt NPs below 5 nm as well as comparable OH anion coverage at the potential where ORR was evaluated. In contrast, the instability of Pt NPs under accelerated potential cycling was found to be strongly dependent on the particle size.

Sheng W.; Vescovo E.; Shuo, C. & Shao-Horn, Y.

2011-12-15T23:59:59.000Z

227

Synthesis, Structure and bonding Analysis of the Polar Intermetallic Phase Ca2Pt2Cd  

SciTech Connect

The polar intermetallic phase Ca2Pt2Cd was discovered during explorations of the Ca-Pt-Cd system. The compound was synthesized by high temperature reactions, and its structure refined by single-crystal X-ray diffraction as orthorhombic, Immm, a = 4.4514(5), b = 5.8415(6), c = 8.5976(9) Å, Z = 2. The structure formally contains infinite, planar networks of [Pt2Cd]4– along the ab plane, which can be described as tessellation of six and four-member rings of the anions, with cations stuffed between the anion layers. The infinite condensed platinum chains show a substantial long–short distortion of 0.52 Å, an appreciable difference between Ca2Pt2Cd (26 valence electrons) and the isotypic but regular Ca2Cu2Ga (29 VE). The relatively large cation proportion diminishes the usual dominance of polar (Pt–Cd) and 5d–5d (Pt–Pt) contributions to the total Hamilton populations.

Samal, Saroj L.; Corbett, John D.

2012-08-14T23:59:59.000Z

228

Measurement of {sup 63}Ni and {sup 59}Ni by accelerator mass spectrometry using characteristic projectile x-rays  

SciTech Connect

The long-lived isotopes of nickel ({sup 59}Ni, {sup 63}Ni) have current and potential use in a number of applications including cosmic radiation studies, biomedical tracing, characterization of low-level radioactive wastes, and neutron dosimetry. Methods are being developed at LLNL for the routine detection of these isotopes by AMS. One intended application is in Hiroshima dosimetry. The reaction {sup 63}Cu(n,p){sup 63}Ni has been identified as one of a small number of reactions which might be used for the direct determination of the fast neutron fluence emitted by the Hiroshima bomb. AMS measurement of {sup 63}Ni(t{sub 1/2} = 100 y) requires the chemical removal of {sup 63}Cu, which is a stable isobar of {sup 63}Ni. Following the electrochemical separation of Ni from gram-sized copper samples, the Cu concentration is further lowered to < 2 x 10{sup -8} (Cu/Ni) using the reaction of Ni with carbon monoxide to form the gas Ni(CO){sub 4}. The Ni(CO){sub 4} is thermally decomposed directly in sample holders for measurement by AMS. After analysis in the AMS spectrometer, the ions are identified using characteristic projectile x-rays, allowing further rejection of remaining {sup 63}Cu. In a demonstration experiment, {sup 63}Ni was measured in Cu wires (2-20 g) which had been exposed to neutrons from a {sup 252}Cf source. We successfully measured {sup 63}Ni at levels necessary for the measurement of Cu samples exposed near the Hiroshima hypocenter. For the demonstration samples, the Cu content was chemically reduced by a factor of 10{sup 12} with quantitative retention of {sup 63}Ni. Detection sensitivity (3{sigma}) was {approximately}20 fg {sup 63}Ni in 1 mg Ni carrier ({sup 63}Ni/Ni {approx} 2 x 10{sup -11}). Significant improvements in sensitivity are expected with planned incremental changes in the methods. Preliminary results indicate that a similar sensitivity is achievable for {sup 59}Ni (t{sub 1/2} = 10{sup 5} y).

McAninch, J.E.; Hainsworth, L.J.; Marchetti, A.A. [and others

1996-05-01T23:59:59.000Z

229

NiW and NiRu Bimetallic Catalysts for Ethylene Steam Reforming: Alternative Mechanisms for Sulfur Resistance  

SciTech Connect

Previous investigations of Ni-based catalysts for the steam reforming of hydrocarbons have indicated that the addition of a second metal can reduce the effects of sulfur poisoning. Two systems that have previously shown promise for such applications, NiW and NiRu, are considered here for the steam reforming of ethylene, a key component of biomass derived tars. Monometallic and bimetallic Al{sub 2}O{sub 3}-supported Ni and W catalysts were employed for ethylene steam reforming in the presence and absence of sulfur. The NiW catalysts were less active than Ni in the absence of sulfur, but were more active in the presence of 50 ppm H{sub 2}S. The mechanism for the W-induced improvements in sulfur resistance appears to be different from that for Ru in NiRu. To probe reasons for the sulfur resistance of NiRu, the adsorption of S and C{sub 2}H{sub 4} on several bimetallic NiRu alloy surfaces ranging from 11 to 33 % Ru was studied using density functional theory (DFT). The DFT studies reveal that sulfur adsorption is generally favored on hollow sites containing Ru. Ethylene preferentially adsorbs atop the Ru atom in all the NiRu (111) alloys investigated. By comparing trends across the various bimetallic models considered, sulfur adsorption was observed to be correlated with the density of occupied states near the Fermi level while C{sub 2}H{sub 4} adsorption was correlated with the number of unoccupied states in the d-band. The diverging mechanisms for S and C{sub 2}H{sub 4} adsorption allow for bimetallic surfaces such as NiRu that enhance ethylene binding without accompanying increases in sulfur binding energy. In contrast, bimetallics such as NiSn and NiW appear to decrease the affinity of the surface for both the reagent and the poison.

Rangan, M.; Yung, M. M.; Medlin, J. W.

2012-06-01T23:59:59.000Z

230

Characterization of nanocrystalline Pd by x-ray diffraction and EXAFS  

DOE Green Energy (OSTI)

Since the fraction of atoms located within a few atomic distances of one or more internal interfaces increases rapidly with decreasing grain size in the nanometer regime, it is expected that the structure of grain boundaries plays an important role in determining and controlling the properties of nanocrystalline materials. A high resolution electron microscopy study of nanocrystalline Pd found no evidence for extended, disordered boundary regions that would differ from boundaries in coarse-grained materials. Recent results from x-ray diffraction, EXAFS and hydriding studies have yielded clear evidence that the boundaries in nanocrystalline Pd are ordered and/or extremely localized in nature. The present paper will summarize and discuss the principal results of these three studies. 12 refs., 4 figs.

Eastman, J.A. (Argonne National Lab., IL (USA)); Fitzsimmons, M.R.; Mueller-Stach, M.; Wallner, G. (Ludwig-Maximilians-Universitaet, Munich (Germany, F.R.)); Elam, W.T. (Naval Research Lab., Washington, DC (USA))

1990-12-01T23:59:59.000Z

231

Local structural and compositional determination via electron scattering: Heterogeneous Cu(001)-Pd surface alloy  

SciTech Connect

We have measured the structure and chemical composition of ultrathin Pd films on Cu(001) using low-energy electron microscopy. We determine their local stoichiometry and structure, with 8.5 nm lateral spatial resolution, by quantitatively analyzing the scattered electron intensity and comparing it to dynamical scattering calculations, as in a conventional low-energy electron diffraction (LEED)-IV analysis. The average t-matrix approximation is used to calculate the total atomic scattering matrices for this random substitutional alloy. As in the traditional LEED analysis, the structural and compositional parameters are determined by comparing the computed diffraction intensity of a trial structure to that measured in experiment. Monte Carlo simulations show how the spatial and compositional inhomogeneity can be used to understand the energetics of Cu-Pd bonding.

Sun, J.; Pohl, K. [Department of Physics, University of New Hampshire, Durham, New Hampshire 03824 (United States); Hannon, J. B. [IBM Research Division, T. J. Watson Research Center, Yorktown Heights, New York 10598 (United States); Kellogg, G. L. [Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States)

2007-11-15T23:59:59.000Z

232

Exchange Coupling Nanophase Fe-Pd Ferromagnets Through Solid State Transformation  

SciTech Connect

This study continues previous work on off stoichiometric Fe-Pd alloys using a combined reaction strategy during thermomechanical processing [1,2]. Severe plastic deformation of the initial disordered fcc gamma phase ( ), followed by heat treatment in the two phase field produces a nano-composite ferromagnet comprised of soft alpha-Fe/ferrite in a high-anisotropy L10 FePd matrix. The length scale and morphology of the transformation products have been characterized using x-ray diffraction, and scanning and transmission electron microscopy. The transformed microstructures exhibit strong texture retention similar to the stoichiometric alloy suggesting a massive ordering mode. The alloy has shown a proclivity to exchange couple at a length scale not in agreement with proposed theories of exchange coupling [3,4]. The magnetic properties were measured using standard vibrating sample magnetometry (VSM). This research has been supported by the National Science Foundation (NSF-DMR).

Shugart, Kathleen N. [University of Virginia, Charlottesville; Ludtka, Gerard Michael [ORNL; Ludtka, Gail Mackiewicz- [ORNL; Soffa, William A [University of Virginia

2011-01-01T23:59:59.000Z

233

Simplified Production of Ni-Based Oxide Dispersion Strengthened  

Science Conference Proceedings (OSTI)

Austenitic Steel Oxidation in Steam: Alloy Composition and Surface Modification ... Ni-Base Alloys for Use as Components in Advanced-USC Steam Turbines.

234

Development of Ni-Fe Hydrogenation Catalyst from D. Gigas ...  

Development of Ni-Fe Hydrogenation Catalyst from D. Gigas Hydrogenase Note: The technology described above is an early stage opportunity. Licensing rights to this ...

235

Cyclic Oxidation Behavior of Detonation Gun Sprayed Ni-20Cr ...  

Science Conference Proceedings (OSTI)

Presentation Title, Cyclic Oxidation Behavior of Detonation Gun Sprayed Ni-20Cr Coating on a Boiler Steel at 900°C. Author(s), Gagandeep Kaushal, Harpreet ...

236

Hot Tearing in Directionally Solidified Ni-Based Superalloys  

Science Conference Proceedings (OSTI)

It is found that in most of the Ni-based superalloys studied there exists a critical ..... welds: minor elements do not individually cause significant increases in heat

237

Synthesis of Ni-Al Intermetallic Nanoparticle Catalysts by Vacuum ...  

Science Conference Proceedings (OSTI)

... methanol decomposition and methane steam reforming, indicating a possibility to develop Ni-Al intermetallic compounds as catalysts for hydrogen production.

238

Thermochemical Simulation of Cu-Ni Smelting Operations  

Science Conference Proceedings (OSTI)

As a second example, an advanced on-line thermochemical simulation of Xstrata Nickel's Sudbury Ni–Cu sulphide smelting plant will be presented. The on-line ...

239

Study of Supercritical CO2 Emulsion in Ni Electroplating and ...  

Science Conference Proceedings (OSTI)

Presentation Title, Study of Supercritical CO2 Emulsion in Ni Electroplating and Application in Fabrication of Defect-Free Micromechanical Component with High  ...

240

Carbon Fiber with Ni-Coated Reinforced Aluminum Alloy Matrix ...  

Science Conference Proceedings (OSTI)

May 1, 2007 ... Carbon Fiber with Ni-Coated Reinforced Aluminum Alloy Matrix Composites by Bianhua Han, Tianjiao Luo, Chunlin Liang,Guangchun Yao, ...

Note: This page contains sample records for the topic "ni pd pt" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

An Exploration of Catalytic Chemistry on Au/Ni(111)  

Science Conference Proceedings (OSTI)

This project explored the catalytic oxidation chemistry that can be effected on a Au/Ni(111) surface alloy. A Au/Ni(111) surface alloy is a Ni(111) surface on which less than 60% of the Ni atoms are replaced at random positions by Au atoms. The alloy is produced by vapor deposition of a small amount of Au onto Ni single crystals. The Au atoms do not result in an epitaxial Au overlayer or in the condensation of the Au into droplets. Instead, Au atoms displace and then replace Ni atoms on a Ni(111) surface, even though Au is immiscible in bulk Ni. The two dimensional structure of the clean Ni surface is preserved. This alloy is found to stabilize an adsorbed peroxo-like O2 species that is shown to be the critical reactant in the low temperature catalytic oxidation of CO and that is suspected to be the critical reactant in other oxidation reactions. This investigation revealed a new, practically important catalyst for CO oxidation that has since been patented.

Sylvia T. Ceyer

2011-12-09T23:59:59.000Z

242

Determination of Atomistic Structure of Ni-Base Single Crystal ...  

Science Conference Proceedings (OSTI)

l-2-1, Sengen, Tsukuba Science City, 305, Japan. *Department of ... The atomic locations of alloying elements in some Ni-base single crystal superalloys have ...

243

Ni-Based Molecular Electrocatalysts for Hydrogen Oxidation  

NLE Websites -- All DOE Office Websites (Extended Search)

Ni-Based Molecular Electrocatalysts for Hydrogen Oxidation Dan DuBois National Renewable Energy Laboratory Nicolet, Y.; de Lacey, A. L.; Vernde, X.; Fernandez, V. M.; Hatchikian,...

244

Lessons Learned in Sputtering TiNi Thin Film  

Science Conference Proceedings (OSTI)

Experimental results have been published in journals and conference proceedings, but as yet TiNi thin film is not commercially available. The author and ...

245

Catalytic Properties of Ni-Al Intermetallic Nanoparticle Catalysts for ...  

Science Conference Proceedings (OSTI)

In order to pursue high catalytic performance of Ni-Al intermetallic ... very high catalytic activity for methanol decomposition and methane steam reforming.

246

Fusion of radioactive $^{132}$Sn with $^{64}$Ni  

E-Print Network (OSTI)

Evaporation residue and fission cross sections of radioactive $^{132}$Sn on $^{64}$Ni were measured near the Coulomb barrier. A large sub-barrier fusion enhancement was observed. Coupled-channel calculations including inelastic excitation of the projectile and target, and neutron transfer are in good agreement with the measured fusion excitation function. When the change in nuclear size and shift in barrier height are accounted for, there is no extra fusion enhancement in $^{132}$Sn+$^{64}$Ni with respect to stable Sn+$^{64}$Ni. A systematic comparison of evaporation residue cross sections for the fusion of even $^{112-124}$Sn and $^{132}$Sn with $^{64}$Ni is presented.

J. F. Liang; D. Shapira; J. R. Beene; C. J. Gross; R. L. Varner; A. Galindo-Uribarri; J. Gomez del Campo; P. A. Hausladen; P. E. Mueller; D. W. Stracener; H. Amro; J. J. Kolata; J. D. Bierman; A. L. Caraley; K. L. Jones; Y. Larochelle; W. Loveland; D. Peterson

2007-04-05T23:59:59.000Z

247

Microstructure Control of Ni Base Alloys with High Volume Fraction ...  

Science Conference Proceedings (OSTI)

hypo-stoichiometric composition of Ni3V, formation of "multi- variant structure ... reasons; one is the high TC (1318 K) at its stoichiometric composition [1, 2], and ...

248

COMMENTS ON ANOMALOUS EFFECTS IN CHARGING OF PD POWDERS WITH HIGH DENSITY HYDROGEN ISOTOPES  

DOE Green Energy (OSTI)

In Kitamura, et al, Pd-containing materials are exposed to isotopes of hydrogen and anomalous results obtained. These are claimed to be a replication of another experiment conducted by Arata and Zhang. Erroneous basic assumptions are pointed out herein that alter the derived conclusions significantly. The final conclusion is that the reported results are likely normal chemistry combined with noise. Thus the claim to have proven that cold fusion is occurring in these systems is both premature and unlikely.

Shanahan, K.

2009-10-01T23:59:59.000Z

249

Glass forming ability of the Mo-Pd system studied by thermodynamic modeling and ion beam mixing  

SciTech Connect

Glass forming ability/range of the Mo-Pd binary metal system was studied by thermodynamic calculations employing Miedema's model and ion beam mixing of multiple metal layers. The thermodynamic calculations predict a narrow composition range of 8-26 at% Pd, within which metallic glass formation is energetically favored, whereas the experimental results showed that ion beam mixing was able to synthesize metallic glasses within a composition range 13-30 at% Pd, which was well in accordance with the prediction. Besides, in the Mo{sub 70}Pd{sub 30} multilayered films, with varying the irradiation dose, a dual-phase metallic glass was formed, and it could be considered as an intermediate state. The possible mechanism for the formation of the metallic glasses was also discussed in terms of the atomic collision theory.

Ding, N.; Li, J. H.; Liu, B. X.

2011-07-01T23:59:59.000Z

250

Synthesis of Methanol and Dimethyl Ether from Syngas over Pd/ZnO/Al2O3 Catalysts  

SciTech Connect

A Pd/ZnO/Al2O3 catalyst was developed for the synthesis of methanol and dimethyl ether (DME) from syngas. Studied were temperatures of operation ranging from 250°C to 380°C. High temperatures (e.g. 380°C) are necessary when combining methanol and DME synthesis with a methanol to gasoline (MTG) process in a single reactor bed. A commercial Cu/ZnO/Al2O3 catalyst, utilized industrially for the synthesis of methanol at 220-280°C, suffers from a rapid deactivation when the reaction is conducted at high temperature (>320°C). On the contrary, a Pd/ZnO/Al2O3 catalyst was found to be highly stable for methanol and DME synthesis at 380°C. The Pd/ZnO/Al2O3 catalyst was thus further investigated for methanol and DME synthesis at P=34-69 bars, T= 250-380°C, GHSV= 5 000-18 000 h-1, and molar feeds H2/CO= 1, 2, and 3. Selectivity to DME increased with decreasing operating temperature, and increasing operating pressure. Increased GHSV’s and H2/CO syngas feed ratios also enhanced DME selectivity. Undesirable CH4 formation was observed, however, can be minimized through choice of process conditions and by catalyst design. By studying the effect of the Pd loading and the Pd:Zn molar ratio the formulation of the Pd/ZnO/Al2O3 catalyst was optimized. A catalyst with 5% Pd and a Pd:Zn molar ratio of 0.25:1 has been identified as the preferred catalyst. Results indicate that PdZn particles are more active than Pdº particles for the synthesis of methanol and less active for CH4 formation. A correlation between DME selectivity and the concentration of acid sites of the catalysts has been established. Hence, two types of sites are required for the direct conversion of syngas to DME: 1) PdZn particles are active for the synthesis of methanol from syngas, and 2) acid sites which are active for the conversion of methanol to DME. Additionally, CO2 formation was problematic as PdZn was found to be active for the water-gas-shift (WGS) reaction, under all the conditions evaluated.

Lebarbier, Vanessa MC; Dagle, Robert A.; Kovarik, Libor; Lizarazo Adarme, Jair A.; King, David L.; Palo, Daniel R.

2012-10-01T23:59:59.000Z

251

Hydrogen Sensor Based on Pd/GeO{sub 2} Using a Low Cost Electrochemical Deposition  

Science Conference Proceedings (OSTI)

This work reports on a synthesis of sub micron germanium dioxide (GeO{sub 2}) on porous silicon (PS) by electrochemical deposition. n-type Si (100) wafer was used to fabricate (PS) using conventional method of electrochemical etching in HF based solution. A GeCl{sub 4} was directly hydrolyzed by hydrogen peroxide to produce pure GeO{sub 2}, and then electrochemically deposited on PS. Followed by palladium (Pd) contact on GeO{sub 2} /PS was achieved by using RF sputtering technique. The grown GeO{sub 2} crystals were characterized using SEM and EDX. I-V characteristics of Pd/ GeO{sub 2} were recorded before and after hydrogen gas exposure as well as with different H{sub 2} concentrations and different applied temperatures. The sensitivity of Pd/ GeO{sub 2} also has been investigated it could be seen to increase significantly with increased hydrogen concentration while it decreased with increase temperature.

Jawad, M. J.; Hashim, M. R. [School of Physics, Universiti Sains Malaysia, 11800-Penang (Malaysia); Ali, N. K. [Material Innovations and Nanoelectronics Research Group, Faculty of Electrical Engineering, Department of electronic engineering, Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia)

2011-05-25T23:59:59.000Z

252

Metal-and hydrogen-bonding competition during water absorption on Pd(111) and Ru(0001)  

SciTech Connect

The initial stages of water adsorption on the Pd(111) and Ru(0001) surfaces have been investigated experimentally by Scanning Tunneling Microscopy in the temperature range between 40 K and 130 K, and theoretically with Density Functional Theory (DFT) total energy calculations and STM image simulations. Below 125 K water dissociation does not occur at any appreciable rate and only molecular films are formed. Film growth starts by the formation of flat hexamer clusters where the molecules bind to the metal substrate through the O-lone pair while making H-bonds with neighboring molecules. As coverage increases, larger networks of linked hexagons are formed with a honeycomb structure, which requires a fraction of the water molecules to have their molecular plane perpendicular to the metal surface with reduced water-metal interaction. Energy minimization favors the growth of networks with limited width. As additional water molecules adsorb on the surface they attach to the periphery of existing islands, where they interact only weakly with the metal substrate. These molecules hop along the periphery of the clusters at intermediate temperatures. At higher temperatures they bind to the metal to continue the honeycomb growth. The water-Ru interaction is significantly stronger than the water-Pd interaction, which is consistent with the greater degree of hydrogen-bonded network formation and reduced water-metal bonding observed on Pd relative to Ru.

Tatarkhanov, Mouslim; Ogletree, D. Frank; Rose, Franck; Mitsui, Toshiyuki; Fomin, Evgeny; Rose, Mark; Cerda, Jorge I.; Salmeron, Miquel

2009-09-03T23:59:59.000Z

253

Break-up of Pt catalyst surfaces by high CO coverage  

E-Print Network (OSTI)

and atomic arrangement of catalyst surface under reactionof reactant molecules on the catalyst surfaces are the norm.Break-up of Pt catalyst surfaces by high CO coverage Feng

Tao, Feng

2010-01-01T23:59:59.000Z

254

Size Influence on the Oxygen Reduction Reaction Activity and Instability of Supported Pt Nanoparticles  

E-Print Network (OSTI)

Size-dependent oxygen reduction reaction activity (ORR) and instability of Pt nanoparticles is of great importance in proton exchange membrane fuel cell applications. In this study, the size-dependence of ORR activity on ...

Sheng, Wenchao

255

PT symmetry and necessary and sufficient conditions for the reality of energy eigenvalues  

E-Print Network (OSTI)

Despite its common use in quantum theory, the mathematical requirement of Dirac Hermiticity of a Hamiltonian is sufficient to guarantee the reality of energy eigenvalues but not necessary. By establishing three theorems, this paper gives physical conditions that are both necessary and sufficient. First, it is shown that if the secular equation is real, the Hamiltonian is necessarily PT symmetric. Second, if a linear operator C that obeys the two equations [C,H]=0 and C^2=1 is introduced, then the energy eigenvalues of a PT-symmetric Hamiltonian that is diagonalizable are real only if this C operator commutes with PT. Third, the energy eigenvalues of PT-symmetric Hamiltonians having a nondiagonalizable, Jordan-block form are real. These theorems hold for matrix Hamiltonians of any dimensionality.

Carl M. Bender; Philip D. Mannheim

2009-02-09T23:59:59.000Z

256

EFFECT OF PRETREATMENT ON PT-CO/C CATHODE CATALYSTS FOR THE OXYGEN-REDUCTION REACTION  

DOE Green Energy (OSTI)

In order to reduce the precious metal loading without sacrificing activity and stability, a new method for the preparation of bimetallic catalysts is proposed. Currently, Pt-alloy particles, with 2 to 3 nm in diameter, are loaded on high surface area carbon supports. Of the Pt loaded, only the surface atoms interact with the reactants. In order to increase the Pt utilization per metal particle the new process for catalyst preparation will incorporate a non-noble transition metal core coated with a skin layer of Pt deposited on high surface area carbon. The effect of reducing agent strength during synthesis was also explored. It was determined that the Co addition has a higher impact on catalyst when used with NaBH4 as reducing agent as compared to NaCOOH.

Fox, E.

2009-05-13T23:59:59.000Z

257

Effect of near atmospheric pressure nitrogen plasma treatment on Pt/ZnO interface  

SciTech Connect

The effect of near atmospheric pressure nitrogen plasma (NAP) treatment of platinum (Pt)/zinc oxide (ZnO) interface was investigated. NAP can nitride the ZnO surface at even room temperature. Hard x-ray photoelectron spectroscopy revealed that NAP treatment reduced the surface electron accumulation at the ZnO surface and inhibited the Zn diffusion into the Pt electrode, which are critical issues affecting the Schottky barrier height and the ideality factor of the Pt/ZnO structure. After NAP treatment, the Pt Schottky contact indicated an improvement of electrical properties. NAP treatment is effective for the surface passivation and the Schottky contact formation of ZnO.

Nagata, Takahiro; Haemori, Masamitsu; Chikyow, Toyohiro [International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Yamashita, Yoshiyuki [International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Synchrotron X-ray Station at SPring-8, National Institute for Materials Science, 1-1-1 Koto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Yoshikawa, Hideki; Kobayashi, Keisuke [Synchrotron X-ray Station at SPring-8, National Institute for Materials Science, 1-1-1 Koto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Uehara, Tsuyoshi [Sekisui Chemical Co., Ltd., Wadai, Tsukuba, Ibaraki 300-4292 (Japan)

2012-12-01T23:59:59.000Z

258

Electric field control of domain wall propagation in Pt/Co/GdOx films  

E-Print Network (OSTI)

The influence of a gate voltage on domain wall (DW) propagation is investigated in ultrathin Pt/Co/gadolinium oxide (GdOx) films with perpendicular magnetic anisotropy. The DW propagation field can be enhanced or retarded ...

Bauer, Uwe

259

Pt–metal oxide aerogel catalysts: X-ray photoemission investigation  

Science Conference Proceedings (OSTI)

X-ray photoemission spectroscopy was used to study Pt–metal oxide aerogel catalysts that have been developed to respond to increased NO x emissions of lean-burn engines. Lean-burn engines

A. J. Nelson; John G. Reynolds; R. D. Sanner; P. R. Coronado; L. M. Hair

2001-01-01T23:59:59.000Z

260

NREL Improves Hole Transport in Sensitized CdS?NiO Nanoparticle...  

NLE Websites -- All DOE Office Websites (Extended Search)

effective sensitizing dyes for p-type NiO. One of the factors limiting the use of NiO for solar cell application is the low hole conductivity in p-NiO. A team of researchers from...

Note: This page contains sample records for the topic "ni pd pt" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Influence of support material on Ni catalysts for propane dry reforming to synthesis gas.  

E-Print Network (OSTI)

??Ni/SiO2 and Ni/Mg(Al)O catalysts with difference metal loadings have been prepared. The activity, selectivity and stability of supported Ni catalysts for propane dry reforming to… (more)

Dai, Xin

2008-01-01T23:59:59.000Z

262

El Ni~no and La Ni~na: Causes and Global Consequences Michael J McPhaden  

E-Print Network (OSTI)

of an El Niño, the Aleutian low pressure system tends to be larger and more intense than in other years

263

Formation of a Novel Ordered Ni3Al Surface Structure by Codeposition on NiAl(110)  

SciTech Connect

The formation of a new type of ordered 2D Ni3Al overlayer by low-temperature codeposition on NiAl(110) is demonstrated by kinetic Monte Carlo simulation of a multisite atomistic lattice-gas model with a precise treatment of surface diffusion kinetics. Simultaneous codeposition with 3?1 Ni?Al yields poor ordering at 300 K but well-ordered structures by ?500??K. Sequential codeposition of Ni then Al yields unmixed core-ring nanostructures at 300 K but strong intermixing and ordering by ?500??K.

Han, Yong; Unal, Baris; Evans, James W.

2012-05-23T23:59:59.000Z

264

Almost zero-dimensional PT-symmetric quantum field theories  

E-Print Network (OSTI)

In 1992 Bender, Boettcher, and Lipatov proposed in two papers a new and unusual nonperturbative calculational tool in quantum field theory. The objective was to expand the Green's functions of the quantum field theory as Taylor series in powers of the space-time dimension D. In particular, the vacuum energy for a massless \\phi^{2N} (N=1,2,3,...) quantum field theory was studied. The first two Taylor coefficients in this dimensional expansion were calculated {\\it exactly} and a set of graphical rules were devised that could be used to calculate approximately the higher coefficients in the series. This approach is mathematically valid and gives accurate results, but it has not been actively pursued and investigated. Subsequently, in 1998 Bender and Boettcher discovered that PT-symmetric quantum-mechanical Hamiltonians of the form H=p^2+x^2(ix)^\\epsilon, where \\epsilon\\geq0, have real spectra. These new kinds of complex non-Dirac-Hermitian Hamiltonians define physically acceptable quantum-mechanical theories. Th...

Bender, Carl M

2010-01-01T23:59:59.000Z

265

Kinetics of Ni Sorption in Soils: Roles of Soil Organic Matter and Ni Precipitation  

E-Print Network (OSTI)

Aqueous Model (WHAM),6,20 which is able to account for the effects of solution chemistry and SOM WHAM VI was integrated into the kinetics model to account for the effects of SOM concentrations by an electrostatic model built in WHAM VI for cation exchange on clay minerals. Ni precipitation kinetics were

Sparks, Donald L.

266

Roles of Surface Step on Pt Nanoparticles in Electro-oxidation of Carbon Monoxide and Methanol  

DOE Green Energy (OSTI)

Design of highly active nanoscale catalysts for electro-oxidation of small organic molecules is of great importance to the development of efficient fuel cells. Increasing steps on single-crystal Pt surfaces is shown to enhance the activity of CO and methanol electro-oxidation up to several orders of magnitude. However, little is known about the surface atomic structure of nanoparticles with sizes of practical relevance, which limits the application of fundamental understanding in the reaction mechanisms established on single-crystal surfaces to the development of active, nanoscale catalysts. In this study, we reveal the surface atomic structure of Pt nanoparticles supported on multiwall carbon nanotubes, from which the amount of high-index surface facets on Pt nanoparticles is quantified. Correlating the surface steps on Pt nanoparticles with the electrochemical activity and stability clearly shows the significant role of surface steps in enhancing intrinsic activity for CO and methanol electro-oxidation. Here, we show that increasing surface steps on Pt nanoparticles of {approx}2 nm can lead to enhanced intrinsic activity up to {approx}200% (current normalized to Pt surface area) for electro-oxidation of methanol.

Lee, S.W.; Vescovo, E.; Chen, S.; Sheng, W.; Yabuuchi, N.; Kim, Y.T.; Mitani, T.; Shao-Horn, Y.

2009-10-13T23:59:59.000Z

267

Combined electrochemical/surface science investigations of Pt/Cr alloy electrodes  

DOE Green Energy (OSTI)

Chromium addition improves the performance of carbon-supported Pt electrodes for oxygen reduction in phosphoric acid fuel cells. To clarify the role of chromium and its chemical nature at the electrode surface, we have performed a combined electrochemical/surface science investigation of a series of bulk Pt/sub x/Cr/sub (1-x)/ alloys (0 less than or equal to x less than or equal to 1). In this paper we report the surface characterization of the starting electrodes by XPS, electrochemical results from cyclic voltammetry in 85% phosphoric acid, and post-electrochemical surface characterization. For Cr contents less than 40%, the electrodes were quite stable up to +1.6 V vs DHE. The surface Cr was largely oxidized to Cr/sup +3/ for surfaces at open circuit ad those exposed at potentials < +1.4 V. For intermediate Cr levels, Cr was leached from the surface region by +1.5 V, leaving a porous Pt electrode with increased electrochemical hydrogen adsorption capacity. For Pt/sub 0.2//Cr/sub 0.8/, treatments at +1.4 V and above led to the appearance of Pt/sup 4 +/ and Cr/sup 6 +/ species, apparently stabilized in a porous phosphate overlayer up to 50 A thick. The Pt electrochemical hydrogen adsorption capacity was simultaneously increased by a factor of 15. 18 refs., 4 figs.

Daube, K.A.; Paffett, M.T.; Gottesfeld, S.; Campbell, C.T.

1985-01-01T23:59:59.000Z

268

Wetting at the BaTiO{sub 3}/Pt interface  

SciTech Connect

Using density functional theory, we analyze the wetting conditions for Pt on the (001) surface of ferroelectric BaTiO{sub 3} (BTO). We estimate the surface energy of (100), (110), and (111) Pt to be 2.42, 2.49, and 2.00 J/m{sup 2}, respectively. We find the BTO surface energy to vary between 0.26 and 2.28 J/m{sup 2} depending on termination, polarization, and chemical environment. The interface energy between TiO{sub 2}-terminated out-of-plane polarized BTO and (100) Pt is found to be between 1.64 and 2.62 J/m{sup 2}, indicating that (100) Pt cannot wet BTO for this interface. A similar result is found for an interface with (110) Pt. Cross-sectional transmission electron microscopy of Pt films grown on BTO by molecular beam epitaxy with a low flux at high deposition temperature shows Volmer-Weber islands, consistent with first principles calculations.

Fredrickson, Kurt D.; Posadas, Agham B.; Demkov, Alexander A. [Department of Physics, The University of Texas at Austin, Austin, Texas 78712 (United States)] [Department of Physics, The University of Texas at Austin, Austin, Texas 78712 (United States); Dubourdieu, Catherine; Bruley, John [IBM T. J. Watson Research Center, Yorktown Heights, New York 10598 (United States)] [IBM T. J. Watson Research Center, Yorktown Heights, New York 10598 (United States)

2013-05-14T23:59:59.000Z

269

Compatibility of Pt-3008 with selected components of the selenide isotope generator system  

DOE Green Energy (OSTI)

The first in a new generation of radioisotopic thermoelectric generators being built by Teledyne Energy Systems and designated the Selenide Isotope Generator has thermoelectric materials that can be degraded by reaction with O/sub 2/, H/sub 2/O, CO, and other gases. Consequently, for at least the first ground demonstration system a protective xenon atmosphere will be maintained over the thermoelectrics. The high-temperature portion of the atmosphere-retaining structure will be fabricated from the alloy Pt-3008 (Pt--30 wt % Rh--8 wt % W), which was developed at Oak Ridge National Laboratory. For this application Pt-3008 must be compatible with the various insulations and thermoelectric materials. A study of the compatibility of Pt-3008 with these materials and showed that Pt-3008 was embrittled after exposure to some of the insulations that were not adequately outgassed and by one of the thermoelectric materials (Cu/sub 2/Se) in some of the isothermal tests. It is believed that Pt-3008 will be compatible with the Selenide Isotope Generator materials when they are well outgassed and under the temperature gradient conditions of the operating system.

Keiser, J.R.

1979-04-01T23:59:59.000Z

270

Structural and Electrocatalytic Properties of PtIrCo/C Catalysts for Oxygen Reduction Reaction  

Science Conference Proceedings (OSTI)

This paper describes the results of an investigation of the synthesis of PtIrCo nanoparticles (2-3 nm) for electrocatalytic oxygen reduction reaction. The carbon-supported PtIrCo catalysts (PtIrCo/C) were thermally treated at temperatures ranging from 400 to 900 C. The size, composition, and atomic-scale structures of the PtIrCo/C catalysts were characterized for establishing their correlation with the electrocatalytic activity toward oxygen reduction reaction. The specific activity was found to increase by a factor of 3-5 for the PtIrCo/C catalysts in comparison with Pt/C catalysts. A correlation was identified between the specific activity and the nanoparticle's fcc-type lattice parameter. The specific activity increases whereas the fcc-type lattice parameter decreases with the thermal treatment temperature. This correlation was further substantiated by analyzing the interatomic spatial parameters in the trimetallic nanoparticles based on X-ray absorption fine structure spectroscopic and high-energy XRD experiments. Implications of these findings, along with the durability of the catalysts, to the design of active electrocatalysts were also discussed.

Loukrakpam, Rameshwori; Wanjala, Bridgid N.; Yin, Jun; Fang, Bin; Luo, Jin; Shao, Minhua; Protsailo, Lesia; Kawamura, Tetsuo; Chen, Yongsheng; Petkov, Valeri; Zhong, Chuan-Jian (CMU); (SUNY-Binghamton); (UTC Power); (Toyota); (Penn)

2011-08-29T23:59:59.000Z

271

TUNING OF SIZE AND SHAPE OF AU-PT NANOCATALYST FOR DIRECT METHANOL FUEL CELLS  

DOE Green Energy (OSTI)

In this paper, we report the precise control of the size, shape and surface morphology of Au-Pt nanocatalysts (cubes, blocks, octahedrons and dogbones) synthesized via a seed-mediated approach. Gold 'seeds' of different aspect ratios (1 to 4.2), grown by a silver-assisted approach, were used as templates for high-yield production of novel Au-Pt nanocatalysts at a low temperature (40 C). Characterization by electron microscopy (SEM, TEM, HRTEM), energy dispersive X-ray analysis (EDX), UV-Vis spectroscopy, zeta-potential (surface charge), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and inductively coupled plasma mass spectrometry (ICP-MS) were used to better understand their physico-chemical properties, preferred reactivities and underlying nanoparticle growth mechanism. A rotating disk electrode was used to evaluate the Au-Pt nanocatalysts electrochemical performance in the oxygen reduction reaction (ORR) and the methanol oxidation reaction (MOR) of direct methanol fuel cells. The results indicate the Au-Pt dogbones are partially and in some cases completely unaffected by methanol poisoning during the evaluation of the ORR. The ORR performance of the octahedron particles in the absence of MeOH is superior to that of the Au-Pt dogbones and Pt-black, however its performance is affected by the presence of MeOH.

Murph, S.

2011-04-20T23:59:59.000Z

272

Schottky barrier height behavior of Pt-Ru alloy contacts on single-crystal n-ZnO  

SciTech Connect

We investigated the Schottky barrier height (SBH) behavior of binary alloy Schottky contacts on n-type zinc oxide (n-ZnO) single crystals. Pt-Ru alloy electrodes were deposited on the Zn-polar and O-polar faces of ZnO substrates by combinatorial ion-beam deposition under identical conditions. The crystal structures of the Pt-Ru alloy film changed from the Pt phase (cubic structure) to the Ru phase (hexagonal structure) in the Pt-Ru alloy phase diagram with decreasing Pt content. The SBH, determined from current-voltage measurements, decreased with decreasing Pt content, indicating that the SBH behavior also followed the Pt-Ru alloy phase diagram. The alloy electrodes on the Zn-polar face showed better Schottky properties than those on the O-polar face. Hard x-ray photoelectron spectroscopy revealed a difference in the interface oxidization of the Pt-Ru alloy: the interface of the O-polar face and Pt-Ru mixed phase with poor crystallinity had a more oxidized layer than that of the Zn-polar face. As a result of this oxidization, the O-polar face, Pt-Ru mixed, and Ru phases showed poor Schottky properties.

Nagata, T.; Haemori, M.; Hayakawa, R.; Yoshitake, M.; Chikyow, T. [Advanced Electronic Materials Center, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Volk, J. [Research Institute for Technical Physics and Materials Science, H-1121 Budapest, Konkoly Thege Miklos ut 29-33 (Hungary); Yamashita, Y. [Advanced Electronic Materials Center, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); NIMS Beamline Station at SPring-8, National Institute for Materials Science, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Yoshikawa, H.; Ueda, S.; Kobayashi, K. [NIMS Beamline Station at SPring-8, National Institute for Materials Science, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan)

2010-05-15T23:59:59.000Z

273

Effect of Pt and H{sub 2} on n-butane isomerization over Fe and Mn promoted sulfated zirconia  

Science Conference Proceedings (OSTI)

The activity of a 0.4 wt% Pt-containing Fe and Mn promoted sulfated zirconia (PtSFMZ) catalyst in n-butane isomerization at 35{degrees}C was compared to that of a Pt-free catalyst (SFMZ). The maximum rate of n-butane conversion observed in helium over PtSFMZ was found to be 2.5 times higher than that over the SFMZ catalyst under the same conditions. It is believed that n-butane isomerization proceeds via a bimolecular mechanism in which the formation of hydrogen-deficient intermediates (carbenium ions and butenes), is necessary and the presence of transition metals such as Pt, Fe, and Mn on sulfated zirconia facilitates the formation/accumulation of these intermediates and increases their stability on the catalyst surface. The presence of H{sub 2} had a strong negative effect on n-butane conversion over PtSFMZ, but had no effect over SFMZ. The negative effect of H{sub 2} on PtSFMZ catalyst in n-butane isomerization reaction was attributed to the decreased concentration of butenes in the presence of hydrogen atoms which are formed by the dissociation of H{sub 2} on Pt. The ability of calcined Pt-containing catalysts to activate hydrogen at 35{degrees}C was demonstrated. Reduced SFMZ with or without Pt was not active at 35{degrees}C regardless of the nature of the carrier gas. 42 refs., 5 figs.

Song, Xuemin; Reddy, K.R.; Sayari, A. [Universite Laval, Quebec (Canada)] [Universite Laval, Quebec (Canada)

1996-06-01T23:59:59.000Z

274

Rejuvenation of Ni-based Superalloys GTD444(DS) and René N5(SX)  

Science Conference Proceedings (OSTI)

D3: Weld Solidification Behavior of Ni-base Superalloys for Use in Advanced Supercritical Coal-fired Power Plants · D4: Sputtered Ni-base Superalloys for ...

275

Ni-Base Alloys for Use as Components in Advanced-USC Steam ...  

Science Conference Proceedings (OSTI)

Symposium, Properties, Processing, and Performance of Steels and Ni-Based Alloys for Advanced Steam Conditions. Presentation Title, Ni-Base Alloys for Use

276

Low temperature epitaxial growth of Ge on cube- textured Ni  

SciTech Connect

Quasi- single crystal Ge films were grown on [001]<010> textured Ni substrate at a temperature of 350 oC using an insulating buffer layer of CaF2. A direct deposition of Ge on Ni at 350 oC was shown to alloy with Ni. From x- ray pole figure analysis, it was shown that Ge grew epitaxially with the same orientation as CaF2 and the dispersions in the out- of- plane and in- plane directions were found to be 1.7 0.1o and 6 1o, respectively. In the out- of- plane direction, Ge[111]||CaF2[111]||Ni[001]. In addition, the Ge consisted of four equivalent in- plane oriented domains such that two mutually orthogonal directions: Ge 211 and Ge 011 are parallel to mutually orthogonal directions: Ni 110 and Ni 110 , respectively of the Ni(001) surface. This was shown to be originated from the four equivalent in- plane oriented domains of CaF2 created to minimize the mismatch strain between CaF2 and Ni in those directions.

GIARE, C [Rensselaer Polytechnic Institute (RPI); Palazzo, J [Rensselaer Polytechnic Institute (RPI); Goyal, Amit [ORNL; WANG, G [Rensselaer Polytechnic Institute (RPI); LU, T [Rensselaer Polytechnic Institute (RPI)

2012-01-01T23:59:59.000Z

277

Lanthanide Al-Ni base Ericsson cycle magnetic refrigerants  

DOE Patents (OSTI)

A magnetic refrigerant for a magnetic refrigerator using the Ericsson thermodynamic cycle comprises DyAlNi and (Gd{sub 0.54}Er{sub 0.46})AlNi alloys having a relatively constant {Delta}Tmc over a wide temperature range. 16 figs.

Gschneidner, K.A. Jr.; Takeya, Hiroyuki

1995-10-31T23:59:59.000Z

278

Lanthanide Al-Ni base Ericsson cycle magnetic refrigerants  

DOE Patents (OSTI)

A magnetic refrigerant for a magnetic refrigerator using the Ericsson thermodynamic cycle comprises DyAlNi and (Gd.sub.0.54 Er.sub.0.46)AlNi alloys having a relatively constant .DELTA.Tmc over a wide temperature range.

Gschneidner, Jr., Karl A. (Ames, IA); Takeya, Hiroyuki (Ibaraki, JP)

1995-10-31T23:59:59.000Z

279

Ultrathin Silver Films on Ni(111)  

SciTech Connect

The growth and atomic structure of ultrathin silver films on Ni(111) was investigated by low-energy electron microscopy and diffraction (LEEM/LEED) as well as intensity-voltage [I(V)]-LEEM in the growth temperature range between 470 and 850 K. We find that silver grows in a Stranski-Krastanov mode with a two monolayer thin wetting layer which takes on a p(7 x 7) reconstruction at temperatures lower than 700 K and a ({radical}52 x {radical}52)R13.9{sup o} reconstruction at higher temperatures. The occurrence of the two distinct reconstructions is shown to have profound implications for the growth characteristics of films exhibiting thicknesses of one and two monolayers. The nanoscale I(V) characteristics of the films were analyzed by means of multiple-scattering calculations based on dynamical LEED theory. Furthermore, the vertical interatomic spacing at the interface between the Ag film and the Ni substrate was determined to (2.8 {+-} 0.1) {angstrom} for all film thicknesses (<13 ML) while the uppermost silver layer relaxes by about (4 {+-} 1)% toward the crystal.

Meyer, A.; Flege, J; Rettew, R; Senanayake, S; Schmidt, T; Alamgir, F; Falta, J

2010-01-01T23:59:59.000Z

280

Ultrathin Silver Films on Ni(111)  

SciTech Connect

The growth and atomic structure of ultrathin silver films on Ni(111) was investigated by low-energy electron microscopy and diffraction (LEEM/LEED) as well as intensity-voltage [I(V)]-LEEM in the growth temperature range between 470 and 850 K. We find that silver grows in a Stranski-Krastanov mode with a two monolayer thin wetting layer which takes on a p(7 x 7) reconstruction at temperatures lower than 700 K and a ({radical}52 x {radical}52)R13.9{sup o} reconstruction at higher temperatures. The occurrence of the two distinct reconstructions is shown to have profound implications for the growth characteristics of films exhibiting thicknesses of one and two monolayers. The nanoscale I(V) characteristics of the films were analyzed by means of multiple-scattering calculations based on dynamical LEED theory. Furthermore, the vertical interatomic spacing at the interface between the Ag film and the Ni substrate was determined to (2.8 {+-} 0.1) {angstrom} for all film thicknesses (<13 ML) while the uppermost silver layer relaxes by about (4 {+-} 1)% toward the crystal.

Flege, J.I.; Senanayake, S.; Meyer, A.; Rettew, R.E.; Schmidt, T.; Alamgir, F.M.; Falta, J.

2010-08-16T23:59:59.000Z

Note: This page contains sample records for the topic "ni pd pt" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Surface electrochemistry of CO on Pt(111): Anion Effects  

DOE Green Energy (OSTI)

In-situ studies of CO adsorption by surface x-ray scattering (SXS) and Fourier transform infrared (FTIR) spectroscopy techniques are used to create the link between the macroscopic kinetic rates of CO oxidation and the microscopic level of understanding the structure/site occupancy of CO on Pt(111). A remarkable difference in activity was observed between alkaline and acid solutions. In alkaline solution the oxidation of CO proceeds at low overpotential (<0.2 V) by the surface reaction between the adsorbed CO and OH, the latter forming selectively in the hydrogen underpotential potential region at defect sites. In acid solution these sites are blocked by specific adsorption of anions, and consequently in a solution containing Br{sup -} the ignition potential is shifted positively by 0.6 V. Anions of supporting electrolytes also have dramatic effects on both the potential range of stability and the domain size of the p(2x2)-3CO structure which is formed at 0.05 V. The stability/domain size of this structure increases from KOH (ca. 30 {angstrom} between 0.05 < E < 0.3V), to HClO{sub 4} (ca. 140 {angstrom} between 0.05 < E < 0.6V) to HClO{sub 4} + Br{sup -} (ca 350 {angstrom} between 0.05 < E < 0.8V). The larger the ordered domains of the p(2x2)-CO{sub ad} structure are, the less active the surface is towards CO oxidation.

Markovic, N.M.; Lucas, C.A.; Rodes, A.; Stamenkovic, V.; Ross, P.N.

2001-07-30T23:59:59.000Z

282

Kinetics, FTIR and controlled atmosphere EXAFS study of the effect of chlorine on Pt supported catalysts during oxidation reactions.  

SciTech Connect

The poisoning effect of Cl on the activity of Pt-supported catalysts for CO, methane, and ethane oxidation has been investigated by kinetic studies and in situ IR and controlled atmosphere EXAFS spectroscopies. Catalysts containing 1.5% Pt/Al{sub 2}O{sub 3} were prepared by incipient wetness from H{sub 2}PtCl{sub 6} and Pt(NH{sub 3}){sub 4}(NO{sub 3}){sub 2} precursors. The reduced catalysts have similar dispersion (0.8) as estimated by H{sub 2} chemisorption. The Cl-free catalyst was 10 times more active than the Cl-containing catalyst during CO and ethane oxidation. Addition of HCl to the Cl-free catalyst rendered its activity identical to the catalyst prepared from Cl-containing precursors. The presence of Cl also affects the activity of 2% Pt/SiO{sub 2} catalysts, but to a lower extent. On the Cl-free oxidation catalyst, Pt-Pt and Pt-O bonds were detected using EXAFS, suggesting that the reduced metal particles are not fully oxidized under the reaction conditions. Additionally, chemisorption of CO by the oxidized catalyst indicates that a portion of the reduced Pt atoms is exposed to the reactants. On the Cl-containing catalyst, there are also Pt-Cl as well as Pt-Pt and Pt-O bonds. The later catalyst, however, does not chemisorb CO, indicating that there are no reduced surface Pt atoms. The effect of Cl poisoning on the oxidation activity of Pt supported on silica is similar to that on alumina. IR results show that chlorine significantly reduces the amount of CO adsorbed on metallic Pt sites. At low temperature there is little CO adsorbed on the Cl-containing Pt/silica catalyst, while at higher temperature the amount of adsorbed CO increases, likely due to reduction of the oxidized surface. The catalyst activities correlate well with the amount of reduced surface sites, and a model is proposed to explain the mechanism of chloride poisoning, which is shown to occur mainly by site blocking.

Gracia, F. J.; Wolf, E. E.; Miller, J. T.; Kropf, A. J.; Chemical Engineering; Univ. of Notre Dame; BP Research Center

2002-07-25T23:59:59.000Z

283

Formation of a Novel Ordered Ni3Al Surface Structure by Codeposition on NiAl(110)  

E-Print Network (OSTI)

The formation of a new type of ordered 2D Ni3Al overlayer by low-temperature codeposition on NiAl(110) is demonstrated by kinetic Monte Carlo simulation of a multisite atomistic lattice-gas model with a precise treatment ...

Han, Yong

284

Evaluation of electron capture reaction rates in Ni isotopes in stellar environments  

SciTech Connect

Electron capture rates in Ni isotopes are studied in stellar environments, that is, at high densities and high temperatures during the core-collapse and postbounce explosive nucleosynthesis in supernovae. Reaction rates in {sup 58}Ni and {sup 60}Ni, as well as in {sup 56}Ni, {sup 62}Ni, and {sup 64}Ni, are evaluated by shell-model calculations with the use of a new shell-model Hamiltonian in the fp shell, GXPF1J. While the previous shell-model calculations failed to reproduce the measured peaks of Gamow-Teller strength in {sup 58}Ni and {sup 60}Ni, the present new Hamiltonian is found to reproduce them very well, as well as the capture rates obtained from the observed strengths. Strengths and energies of the Gamow-Teller transitions in {sup 56}Ni, {sup 62}Ni, and {sup 64}Ni are also found to be consistent with the observations.

Suzuki, Toshio [Department of Physics and Graduate School of Integrated Basic Sciences, College of Humanities and Sciences, Nihon University Sakurajosui 3-25-40, Setagaya-ku, Tokyo 156-8550 (Japan); Center for Nuclear Study, University of Tokyo, Hirosawa, Wako-shi, Saitama 351-0198 (Japan); National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588 (Japan); Honma, Michio [Center for Mathematical Sciences, University of Aizu, Aizu-Wakamatsu, Fukushima 965-8580 (Japan); Mao, Helene [ENSPS, Pole API-Parc d'Innovation, Boulevard Sebastien Brant, BP 10413, F-67412 Illkirch Cedex (France); Otsuka, Takaharu [Department of Physics and Center for Nuclear Study, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (United States); Kajino, Toshitaka [National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588 (Japan); Deaprtment of Astronomy, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0033 (Japan)

2011-04-15T23:59:59.000Z

285

Catalytic decomposition of alcohols over size-selected Pt nanoparticles supported on ZrO2: A study of activity, selectivity, and stability  

E-Print Network (OSTI)

, but do not contribute to steady-state catalytic reforming rates. The high reactivity of Pd surfaces in C

Kik, Pieter

286

Modification of Ni state to promote the stability of Ni-Al{sub 2}O{sub 3} catalyst in methane decomposition to produce hydrogen and carbon nanofibers  

SciTech Connect

The methodology was illustrated for modifying the state of Ni to promote the stability of the coprecipitated Ni-Al{sub 2}O{sub 3} catalyst via incorporating ZnO and Cu in methane decomposition to produce hydrogen and carbon nanofibers. The influences of the incorporation on the state of Ni were examined with XRD, TPR, XPS and TEM. For the incorporation of ZnO, ZnAl{sub 2}O{sub 4} spinel-like structure could be formed in the interface between ZnO and Al{sub 2}O{sub 3}. The interaction between Ni and the ZnAl{sub 2}O{sub 4} structure can promote both the activity and the stability of Ni in methane decomposition. The formation of a Ni-Cu alloy from Ni and the incorporated Cu decreases the activity of Ni, however, promotes the stability pronouncedly. - Graphical abstract: Highlights: Black-Right-Pointing-Pointer Methodology for modifying Ni state of coprecipitated Ni-Al{sub 2}O{sub 3} was illustrated. Black-Right-Pointing-Pointer Influence of incorporating ZnO/Cu on Ni state of Ni-Al{sub 2}O{sub 3} was compared. Black-Right-Pointing-Pointer Influence of modifying Ni state on performance of Ni-Al{sub 2}O{sub 3} was investigated.

Chen Jiuling, E-mail: cjlchen@yahoo.com [Department of Catalysis Science and Technology, School of Chemical Engineering, Tianjin University, Tianjin 300072 (China); Qiao Yuanhua; Li Yongdan [Department of Catalysis Science and Technology, School of Chemical Engineering, Tianjin University, Tianjin 300072 (China)

2012-07-15T23:59:59.000Z

287

Balance of Nanostructure and Bimetallic Interactions in Pt Model Fuel Cell Catalysts: An in Situ XAS and DFT Study  

DOE Green Energy (OSTI)

We have studied the effect of nanostructuring in Pt monolayer model electrocatalysts on a Rh(111) single-crystal substrate on the adsorption strength of chemisorbed species. In situ high energy resolution fluorescence detection X-ray absorption spectroscopy at the Pt L(3) edge reveals characteristic changes of the shape and intensity of the 'white-line' due to chemisorption of atomic hydrogen (H(ad)) at low potentials and oxygen-containing species (O/OH(ad)) at high potentials. On a uniform, two-dimensional Pt monolayer grown by Pt evaporation in ultrahigh vacuum, we observe a significant destabilization of both H(ad) and O/OH(ad) due to strain and ligand effects induced by the underlying Rh(111) substrate. When Pt is deposited via a wet-chemical route, by contrast, three-dimensional Pt islands are formed. In this case, strain and Rh ligand effects are balanced with higher local thickness of the Pt islands as well as higher defect density, shifting H and OH adsorption energies back toward pure Pt. Using density functional theory, we calculate O adsorption energies and corresponding local ORR activities for fcc 3-fold hollow sites with various local geometries that are present in the three-dimensional Pt islands.

Friebel, Daniel; Viswanathan, Venkatasubramanian; Miller, Daniel James; Anniyev, Toyli; Ogasawara, Hirohito; Larsen, Ask Hjorth; O'Grady, Christopher P.; Norskov, Jens K.; Nilsson, Anders

2012-05-31T23:59:59.000Z

288

Graphene decorated with PtAu alloy nanoparticles: facile synthesis and promising application for formic acid oxidation  

DOE Green Energy (OSTI)

PtAu alloy nanoparticles (~ 3.2 nm in diameter) are synthesized in poly(diallyldimethylammonium chloride) (PDDA) aqueous solution and uniformly dispersed on graphene nanosheets. PtAu/graphene exhibits high electrocatalytic activity and stability for formic acid oxidation, which is attributed to the high dispersion of PtAu nanoparticles and the specific interaction between PtAu and graphene, indicating a promising catalyst for direct formic acid fuel cells. The facile method can be readily extended to the synthesis of other alloy nanoparticles.

Zhang, Sheng; Shao, Yuyan; Liao, Honggang; Liu, Jun; Aksay, Ilhan A.; Yin, Geping; Lin, Yuehe

2011-03-01T23:59:59.000Z

289

The effect of Ru and Sn additions to Pt on the electrocatalysis of methanol oxidation: An in situ XAS investigation  

DOE Green Energy (OSTI)

Elements such as Ru and Sn used as ad-atoms or as alloying elements are known to enhance methanol oxidation reaction (MOR). Ru, both as alloying element as well as upd deposited on Pt/C is widely acknowledged for enhancing MOR. Sn on the other hand is more controversial, with evidence indicating enhancements for MOR when present as upd layer and marginally effective when present as an alloying element. In situ XAS is used to investigate some of these inconsistencies in the electrocatalysis of MOR. Results indicate that alloying Sn with Pt (Pt{sub 3}Sn primary phase) causes partial filling of the Pt 5 d-band vacancies and increase in the Pt-Pt bond distances which is directly opposite to a similar situation with Ru. Upd Sn however does not perturb Pt structurally or electronically. Ru and Sn (both as alloying element and as upd ad-layer) are associated with oxygenated species, the nature and strength of the Ru. and Sn - oxygen interactions are potential dependent. Hence alloying with Sn renders Pt surface unfavorable for methanol adsorption in contrast to alloying with Ru. Both Ru and Sn however promote MOR via their ability to nucleate oxygenated species on their surface at lower potentials as compared to pure Pt.

Mukerjee, S.; McBreen, J.

1997-07-01T23:59:59.000Z

290

Tiling theory applied to the surface structure of icosahedral AlPdMn quasicrystals  

E-Print Network (OSTI)

Surfaces in i-Al68Pd23Mn9 as observed with STM and LEED experiments show atomic terraces in a Fibonacci spacing. We analyze them in a bulk tiling model due to Elser which incorporates many experimental data. The model has dodecahedral Bergman clusters within an icosahedral tiling T^*(2F) and is projected from the 6D face-centered hypercubic lattice. We derive the occurrence and Fibonacci spacing of atomic planes perpendicular to any 5fold axis, compute the variation of planar atomic densities, and determine the (auto-) correlation functions. Upon interpreting the planes as terraces at the surface we find quantitative agreement with the STM experiments.

Peter Kramer; Zorka Papadopolos; Harald Teuscher

1999-03-04T23:59:59.000Z

291

DPB hydrogen getters on Pd (110) - its action and the effect of impurities  

DOE Green Energy (OSTI)

Density Functional Theory (DFT) is used to investigate the action of hydrogen getter 1,4-diphenyl-butadiyne, or DPB, on Pd(110) surface. We study reaction pathways and energetics of several relevant processes, including H{sub 2} adsorption, dissociation and migration on the metal surface, getter-metal interaction, and the energetics of H uptake by the getter. We also explore the effect of impurities like CO and CO{sub 2} on the action of the getter. Activation barriers for certain reactions are computed to shed light on the feasibility of such processes at room temperature.

Maiti, A; Gee, R

2005-03-11T23:59:59.000Z

292

Geometric and Electronic Structures of the Ni(I) and Methyl-Ni(III)  

NLE Websites -- All DOE Office Websites (Extended Search)

9 9 Geometric and Electronic Structures of the Ni(I) and Methyl-Ni(III) Intermediates of Methyl-Coenzyme M Reductase Methyl-coenzyme M reductase (MCR) from methanogenic archaea catalyzes the terminal step in biological methane synthesis. Using coenzyme B (CoBSH) as the two-electron donor, MCR reduces methyl-coenzyme M (methyl-SCoM) to form methane and the heterodisulfide product, CoBS-SCoM. MCR contains an essential redox active nickel tetrapyrrolic cofactor called coenzyme F430 at its active site, which is active in the reduced Ni(I) state (MCRred1). All of the biologically generated methane, amounting to 1 billion tons per annum globally, is formed by MCR. Furthermore, recent evidence indicates that anaerobic methane oxidation is also catalyzed by MCR and occurs by a reversal of the methane synthesis reaction. Methane is a potent greenhouse gas, trapping 20 times more heat than CO2. In addition, methane is also an important and clean fuel as it produced the least amount of CO2 per unit of heat released. Thus, it is critically important to understand the mechanism of formation of the smallest hydrocarbon in nature.

293

Mesoscale assembly of NiO nanosheets into spheres  

SciTech Connect

NiO solid/hollow spheres with diameters about 100 nm have been successfully synthesized through thermal decomposition of nickel acetate in ethylene glycol at 200 deg. C. These spheres are composed of nanosheets about 3-5 nm thick. Introducing poly(vinyl pyrrolidone) (PVP) surfactant to reaction system can effectively control the products' morphology. By adjusting the quantity of PVP, we accomplish surface areas-tunable NiO assembled spheres from {approx}70 to {approx}200 m{sup 2} g{sup -1}. Electrochemical tests show that NiO hollow spheres deliver a large discharge capacity of 823 mA h g{sup -1}. Furthermore, these hollow spheres also display a slow capacity-fading rate. A series of contrastive experiments demonstrate that the surface area of NiO assembled spheres has a noticeable influence on their discharge capacity. - Graphical abstract: The mesoscale assembly of NiO nanosheets into spheres have been achieved by a solvothermal method. N{sub 2} adsorption/desorption isotherms show the S{sub BET} of NiO is tunable. NiO spheres show large discharge capacity and slow capacity-fading rate.

Zhang Meng, E-mail: meng_zhang@haut.edu.c [School of Materials Science and Engineering, Henan University of Technology, Zhengzhou, Henan 450007 (China); Yan Guojin; Hou Yonggai; Wang Chunhua [School of Materials Science and Engineering, Henan University of Technology, Zhengzhou, Henan 450007 (China)

2009-05-15T23:59:59.000Z

294

Comparison of Bond Scission Sequence of Methanol on Tungsten Monocarbide and Pt-Modified Tungsten Monocarbide  

Science Conference Proceedings (OSTI)

The ability to control the bond scission sequence of O-H, C-H, and C-O bonds is of critical importance in the effective utilization of oxygenate molecules, such as in reforming reactions and in alcohol fuel cells. In the current study, we use methanol as a probe molecule to demonstrate the possibility to control the decomposition pathways by supporting monolayer coverage of Pt on a tungsten monocarbide (WC) surface. Density functional theory (DFT) results reveal that on the WC and Pt/WC surfaces CH{sub 3}OH decomposes via O-H bond scission to form the methoxy (*CH{sub 3} O) intermediate. The subsequent decomposition of methoxy on the WC surface occurs through the C-O bond scission to form *CH{sub 3}, which reacts with surface *H to produce CH{sub 4}. In contrast, the decomposition of methoxy on the Pt/WC surface favors the C-H bond scission to produce *CH{sub 2} O, which prevents the formation of the *CH{sub 3} species and leads to the formation of a *CO intermediate through subsequent deprotonation steps. The DFT predictions are validated using temperature programmed desorption to quantify the gas-phase product yields and high resolution electron energy loss spectroscopy to determine the surface intermediates from methanol decomposition on Pt, WC, and Pt/WC surfaces.

Liu, P.; Stottlemyer, A.L.; Chen, J.G.

2010-09-14T23:59:59.000Z

295

Graphene Monolayer Rotation on Ni(111) Facilities Bilayer Graphene Growth  

Science Conference Proceedings (OSTI)

Synthesis of bilayer graphene by chemical vapor deposition is of importance for graphene-based field effect devices. Here, we demonstrate that bilayer graphene preferentially grows by carbon-segregation under graphene sheets that are rotated relative to a Ni(111) substrate. Rotated graphene monolayer films can be synthesized at growth temperatures above 650 C on a Ni(111) thin-film. The segregated second graphene layer is in registry with the Ni(111) substrate and this suppresses further C-segregation, effectively self-limiting graphene formation to two layers.

Batzill M.; Sutter P.; Dahal, A.; Addou, R.

2012-06-11T23:59:59.000Z

296

EFFECT OF IMPURITIES ON THE PERFORMANCE OF A Pd-Ag DIFFUSER  

DOE Green Energy (OSTI)

A commercially fabricated diffuser purchased from Johnson-Matthey, Inc. was evaluated for performance characterization testing at the Savannah River National Laboratory (SRNL). Different impurities are often present in the feed streams of the process diffusers, but the effect of these impurities on the diffuser performance is currently unknown. Various impurities were introduced into the feed stream of the diffuser at various levels ranging from 0.5% to 10% of the total flow in order to determine the effect that these impurities have on the permeation of hydrogen through the palladium-silver membrane. The introduction of various impurities into the feed stream of the diffuser had a minimal effect on the overall permeation of hydrogen through the Pd-Ag membrane. Of the four impurities introduced into the feed stream, carbon monoxide (CO) was the only impurity that showed any evidence of causing a reduction in the amount of hydrogen permeating through the Pd-Ag membrane. The hydrogen permeation returned to its baseline level after the CO was removed from the feed stream. There were no lasting effects of the CO exposure on the ability of the membrane to effectively separate hydrogen from the non-hydrogen species in the gas stream under the conditions tested.

Morgan, G.

2010-12-16T23:59:59.000Z

297

CHARACTERIZATION OF PD IMPURITIES AND TWIN BOUNDARY DEFECTS IN DETECTOR GRADE CDZNTE CRYSTALS  

Science Conference Proceedings (OSTI)

Synthetic CdZnTe or ''CZT'' crystals are highly suitable for {gamma}-spectrometers operating at the room temperature. Secondary phases (SP) in CZT are known to inhibit detector performance, particularly when they are present in large numbers or dimensions. These SP may exist as voids or composites of non-cubic phase metallic Te layers with bodies of polycrystalline and amorphous CZT material and voids. Defects associated with crystal twining may also influence detector performance in CZT. Using transmission electron microscopy, we identify two types of defects that are on the nano scale. The first defect consists of 40 nm diameter metallic Pd/Te bodies on the grain boundaries of Te-rich composites. Although the nano-Pd/Te bodies around these composites may be unique to the growth source of this CZT material, noble metal impurities like these may contribute to SP formation in CZT. The second defect type consists of atom-scale grain boundary dislocations. Specifically, these involve inclined ''finite-sized'' planar defects or interfaces between layers of atoms that are associated with twins. Finite-sized twins may be responsible for the subtle but observable striations that can be seen with optical birefringence imaging and synchrotron X-ray topographic imaging.

Duff, M.

2011-06-22T23:59:59.000Z

298

ARM - Field Campaign - MASRAD: Cloud Study from the 2NFOV at Pt. Reyes  

NLE Websites -- All DOE Office Websites (Extended Search)

govCampaignsMASRAD: Cloud Study from the 2NFOV at Pt. Reyes Field govCampaignsMASRAD: Cloud Study from the 2NFOV at Pt. Reyes Field Campaign Campaign Links AMF Point Reyes Website Related Campaigns MArine Stratus Radiation Aerosol and Drizzle (MASRAD) IOP 2005.03.14, Miller, AMF Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Campaign : MASRAD: Cloud Study from the 2NFOV at Pt. Reyes Field Campaign 2005.06.02 - 2005.09.30 Lead Scientist : Warren Wiscombe For data sets, see below. Description Cloud optical depth is one of the most important cloud optical properties, and vital for any cloud-radiation parameterization. Our ARM Science Team project has pioneered an algorithm to retrieve cloud optical depth in a fully three-dimensional cloud situation using zenith radiances from the ARM

299

Ultra-low loading Pt nanocatalysts prepared by atomic layer deposition on carbon aerogels  

SciTech Connect

Using atomic layer deposition (ALD), we show that Pt nanoparticles can be deposited on the inner surfaces of carbon aerogels (CA). The resultant Pt-loaded materials exhibit high catalytic activity for the oxidation of CO even at loading levels as low as {approx}0.05 mg Pt/cm{sup 2}. We observe a conversion efficiency of nearly 100% in the temperatures range 150-250 C, and the total conversion rate seems to be only limited by the thermal stability of our CA support in ambient oxygen. Our ALD approach described here is universal in nature, and can be applied to the design of new catalytic materials for a variety of applications, including fuel cells, hydrogen storage, pollution control, green chemistry, and liquid fuel production.

King, J S; Wittstock, A; Biener, J; Kucheyev, S O; Wang, Y M; Baumann, T F; Giri, S; Hamza, A V; Baeumer, M; Bent, S F

2008-04-21T23:59:59.000Z

300

Thermoelectric performance of electron and hole doped PtSb2  

Science Conference Proceedings (OSTI)

We investigate the thermoelectric properties of electron and hole doped PtSb2. Our results show that for doping of 0.04 holes per unit cell (1:5 1020 cm 3) PtSb2 shows a high Seebeck coefficient at room temperature, which can also be achieved at other temperatures by controlling the carrier concentration (both electron and hole). The electrical conductivity becomes temperature independent when the doping exceeds some 0.2 electrons/holes per unit cell. The figure of merit at 800 K in electron and hole doped PtSb2 is comparatively low at 0.13 and 0.21, respectively, but may increase significantly with As alloying due to the likely opening of a band gap and reduction of the lattice thermal conductivity

Saeed, Yasir [King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia; Singh, Nirprenda [King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia; Schwingenschlogl, Udo [King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia; Parker, David S [ORNL

2013-01-01T23:59:59.000Z

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301

Power-law scaling of asymmetries in viscous flow with PT-symmetric inflow and outflow  

E-Print Network (OSTI)

In recent years, open systems with balanced loss and gain, that are invariant under the combined parity and time-reversal (PT) operations, have been studied via asymmetries of their solutions. They represent systems as diverse as coupled optical waveguides, silicon photonic circuits, and electrical or mechanical oscillators. We numerically investigate the asymmetries of incompressible viscous flow in two and three dimensions with "balanced" inflow-outflow (PT-symmetric) configurations. By introducing configuration-dependent classes of asymmetry functions in velocity, kinetic energy density, and vorticity fields, we find that the flow asymmetries exhibit power-law scaling in the laminar regime with the Reynolds number ranging over four decades. At small Reynolds numbers, the flow asymmetries in the balanced configurations are orders of magnitude smaller than those that occur in traditional configurations. Our results imply that PT-symmetric inflow-outflow configurations provide a hitherto unexplored avenue to tune flow properties.

Huidan; Yu; Xi Chen; Yousheng Xu; Yogesh N. Joglekar

2013-04-19T23:59:59.000Z

302

Evaluation of the dose distribution for prostate implants using various {sup 125}I and {sup 103}Pd sources  

Science Conference Proceedings (OSTI)

Recently, several different models of {sup 125}I and {sup 103}Pd brachytherapy sources have been introduced in order to meet the increasing demand for prostate seed implants. These sources have different internal structures; hence, their TG-43 dosimetric parameters are not the same. In this study, the effects of the dosimetric differences among the sources on their clinical applications were evaluated. The quantitative and qualitative evaluations were performed by comparisons of dose distributions and dose volume histograms of prostate implants calculated for various designs of {sup 125}I and {sup 103}Pd sources. These comparisons were made for an identical implant scheme with the same number of seeds for each source. The results were compared with the Amersham model 6711 seed for {sup 125}I and the Theragenics model 200 seed for {sup 103}Pd using the same implant scheme.

Meigooni, Ali S.; Luerman, Christine M.; Sowards, Keith T. [Department of Radiation Medicine, North Shore University Hospital, Manhasset, New York 11030 and Department of Radiation Medicine, University of Kentucky Medical Center, Lexington, Kentucky 40536 (United States); Department of Radiation Medicine, University of Kentucky Medical Center, Lexington, Kentucky 40536 (United States); James Graham Brown Cancer Center, University of Louisville, Louisville, Kentucky 40202 (United States)

2009-04-15T23:59:59.000Z

303

$^{64}$Ni+$^{64}$Ni fusion reaction calculated with the density-constrained time-dependent Hartree-Fock formalism  

E-Print Network (OSTI)

We study fusion reactions of the $^{64}$Ni+$^{64}$Ni system using the density-constrained time-dependent Hartree-Fock (TDHF) formalism. In this formalism the fusion barriers are directly obtained from TDHF dynamics. In addition, we incorporate the entrance channel alignments of the slightly deformed (oblate) $^{64}$Ni nuclei due to dynamical Coulomb excitation. We show that alignment leads to a fusion barrier distribution and alters the naive picture for defining which energies are actually sub-barrier. We also show that core polarization effects could play a significant role in fusion cross section calculations.

A. S. Umar; V. E. Oberacker

2007-09-25T23:59:59.000Z

304

Excellent Sulfur Resistance of Pt/BaO/CeO2 Lean NOx Trap Catalysts  

SciTech Connect

In this work, we investigated the NOx storage behavior of Pt-BaO/CeO2 catalysts, especially in the presence of SO2. High surface area CeO2 (~ 110 m2/g) with a rod like morphology was synthesized and used as a support. The Pt-BaO/CeO2 sample demonstrated slightly higher NOx conversion in the entire temperature range studied compared with Pt-BaO/?-Al2O3. More importantly, this ceria-based catalyst showed higher sulfur tolerance than the alumina-based one. The time of complete NOx uptake was maintained even after exposing the sample to ~3 g/L of SO2. The same sulfur exposure, on the other hand, eliminated the complete NOx uptake time on the alumina-based NOx storage catalysts. TEM images show no evidence of either Pt sintering or BaS phase formation during reductive de-sulfation up to 600°C on the ceria based catalyst, while the same process over the alumina-based catalyst resulted in both a significant increase in the average Pt cluster size and the agglomeration of a newly-formed BaS phase into large crystallites. XPS results revealed the presence of about 5 times more residual sulfur after reductive de-sulfation at 600°C on the alumina based catalysts in comparison with the ceria-based ones. All of these results strongly support that, besides their superior intrinsic NOx uptake properties, ceria based catalysts have a) much higher sulfur tolerance and b) excellent resistance against Pt sintering when they are compared to the widely used alumina based catalysts.

Kwak, Ja Hun; Kim, Do Heui; Szanyi, Janos; Peden, Charles HF

2008-10-21T23:59:59.000Z

305

Powder Metallurgy Processing of Replicated Ni-Mn-Ga Foams  

Science Conference Proceedings (OSTI)

Development of a SMA-Based Drive Unit for Prehension Orthoses to Support Disabled People · Effect of H in Metals and Alloys: An Application to bcc W and NiTi ...

306

The Application of CALPHAD Calculations to Ni-Based Superalloys  

Science Conference Proceedings (OSTI)

The Cr content was raised from 20 to 24wt% to increase coal ash corrosion resistance. 2. ..... Ni-based Alloys”, Univ.Cambridge report to Rolls-Royce plc.,. Derby ...

307

Electrochemically Preparing of Ni-Fe Alloys in Molten Sodium ...  

Science Conference Proceedings (OSTI)

A Pilot-plant Scale Test of Coal-based Rotary Kiln Direct Reduction of Laterite Ore for Fe-Ni Production · A Pilot-plant Scale Test on DRI Preparation from ...

308

Characterization of New Phases in the Ti-Pt System Relevant to ...  

Science Conference Proceedings (OSTI)

Development of a SMA-Based Drive Unit for Prehension Orthoses to Support Disabled People · Effect of H in Metals and Alloys: An Application to bcc W and NiTi ...

309

Structure and Electrocatalysis of Sputtered RuPt Thin-film Electrodes  

DOE Green Energy (OSTI)

The structural and electrochemical properties of RuPt thin-film electrodes fabricated by RF magnetron sputtering have been investigated. Grazing incidence X-ray diffraction data show a transition from a face-centered-cubic (fcc) to hexagonal-cubic-packed (hcp) structure as Ru percentage increases. The transition occurs gradually between 32-58% Ru, which is significantly different from the bulk RuPt phase diagram. The catalytic activity of the thin-film electrodes for methanol oxidation shows a broad peak near 40-60% Ru, consistent with previous reports. The relationship between catalytic activity and film structure is discussed and contrasted with previous investigations.

Kim, T-W

2005-02-02T23:59:59.000Z

310

Oxidation of stepped Pt(111) studied by x-ray photoelectron spectroscopy and density functional theory  

SciTech Connect

In this comparative density functional theory and x-ray photoelectron spectroscopy study on the interaction of oxygen with stepped Pt(111) surfaces, we show that both the initial adsorption and oxidation occur at the steps rather than terraces. An equivalent behavior was observed for the oxide formation at higher chemical potentials, where, after the formation of a one-dimensional PtO{sub 2}-type oxide at the steps, similar oxide chains form on the (111) terraces, indicating the initial stages of bulk oxide formation.

Bandlow, Jochen; Kaghazchi, Payam; Jacob, Timo [Institut fuer Elektrochemie, Universitaet Ulm, Albert-Einstein-Allee 47, D-89069 Ulm (Germany); Papp, C.; Traenkenschuh, B.; Streber, R.; Lorenz, M. P. A.; Fuhrmann, T.; Steinrueck, H.-P. [Lehrstuhl fuer Physikalische Chemie II, Universitaet Erlangen-Nuernberg, Egerlandstr. 3, D-91058 Erlangen (Germany); Denecke, R. [Wilhelm-Ostwald-Institut fuer Physikalische und Theoretische Chemie, Universitaet Leipzig, Linnestr. 2, D-04103 Leipzig (Germany)

2011-05-01T23:59:59.000Z

311

Design of graphene sheets-supported Pt catalyst layer in PEM fuel cells  

DOE Green Energy (OSTI)

A series of cathodes using Pt supported onto graphene sheets with different contents of carbon black in the catalyst layer were prepared and characterized. Carbon black was added as a spacer between two-dimensional graphene sheets in the catalyst layer to study its effect on the performances of proton exchange membrane fuel cell. Electrochemical properties and surface morphology of the cathodes with and without carbon black were characterized using cyclic voltammetry, ac-impedance spectroscopy, electrochemical polarization technique, and scanning electron microscopy. The results indicated that carbon black effectively modifies the array of graphene supports, resulting in more Pt nanoparticles available for electrochemical reaction and better mass transport in the catalyst layer.

Park, Seh K.; Shao, Yuyan; Wan, Haiying; Rieke, Peter C.; Viswanathan, Vilayanur V.; Towne, Silas A.; Saraf, Laxmikant V.; Liu, Jun; Lin, Yuehe; Wang, Yong

2011-03-01T23:59:59.000Z

312

Nanostructured electrocatalyst for fuel cells : silica templated synthesis of Pt/C composites.  

DOE Green Energy (OSTI)

Platinum-based electrocatalysts are currently required for state-of-the-art fuel cells and represent a significant portion of the overall fuel cell cost. If fuel cell technology is to become competitive with other energy conversion technologies, improve the utilization of precious metal catalysts is essential. A primary focus of this work is on creating enhanced nanostructured materials which improve precious-metal utilization. The goal is to engineer superior electrocatalytic materials through the synthesis, development and investigation of novel templated open frame structures synthesized in an aerosol-based approach. Bulk templating methods for both Pt/C and Pt-Ru composites are evaluated in this study and are found to be limited due to the fact that the nanostructure is not maintained throughout the entire sample. Therefore, an accurate examination of structural effects was previously impossible. An aerosol-based templating method of synthesizing nanostructured Pt-Ru electrocatalysts has been developed wherein the effects of structure can be related to electrocatalytic performance. The aerosol-based templating method developed in this work is extremely versatile as it can be conveniently modified to synthesize alternative materials for other systems. The synthesis method was able to be extended to nanostructured Pt-Sn for ethanol oxidation in alkaline media. Nanostructured Pt-Sn electrocatalysts were evaluated in a unique approach tailored to electrocatalytic studies in alkaline media. At low temperatures, nanostructured Pt-Sn electrocatalysts were found to have significantly higher ethanol oxidation activity than a comparable nanostructured Pt catalyst. At higher temperatures, the oxygen-containing species contribution likely provided by Sn is insignificant due to a more oxidized Pt surface. The importance of the surface coverage of oxygen-containing species in the reaction mechanism is established in these studies. The investigations in this work present original studies of anion exchange ionomers as entrapment materials for rotating disc electrode (RDE) studies in alkaline media. Their significance is linked to the development of membrane electrode assemblies (MEAs) with the same ionomer for a KOH-free alkaline fuel cell (AFC).

Stechel, Ellen Beth; Switzer, Elise E.; Fujimoto, Cy H.; Atanassov, Plamen Borissov; Cornelius, Christopher James; Hibbs, Michael R.

2007-09-01T23:59:59.000Z

313

Tests of Four PT-415 Coolers Installed in the Drop-in Mode  

DOE Green Energy (OSTI)

The superconducting magnets and absorbers for MICE will be cooled using PT415 pulse tube coolers. The cooler 2nd stage will be connected to magnets and the absorbers through a helium or hydrogen re-condensing system. It was proposed that the coolers be connected to the magnets in such a way that the cooler can be easily installed and removed, which permits the magnets to be shipped without the coolers. The drop-in mode requires that the cooler 1st stage be well connected to the magnet shields and leads through a low temperature drop demountable connection. The results of the PT415 drop-in cooler tests are presented.

Green, Michael A.; Wang, S.T.

2008-07-08T23:59:59.000Z

314

PT symmetry, Cartan decompositions, Lie triple systems and Krein space related Clifford algebras  

E-Print Network (OSTI)

Gauged PT quantum mechanics (PTQM) and corresponding Krein space setups are studied. For models with constant non-Abelian gauge potentials and extended parity inversions compact and noncompact Lie group components are analyzed via Cartan decompositions. A Lie triple structure is found and an interpretation as PT-symmetrically generalized Jaynes-Cummings model is possible with close relation to recently studied cavity QED setups with transmon states in multilevel artificial atoms. For models with Abelian gauge potentials a hidden Clifford algebra structure is found and used to obtain the fundamental symmetry of Krein space related J-selfadjoint extensions for PTQM setups with ultra-localized potentials.

Uwe Guenther; Sergii Kuzhel

2010-06-06T23:59:59.000Z

315

g factors of the low-lying states in {sup 106}Pd: Examination of the vibrational character of {sup 106}Pd  

SciTech Connect

The transient field (TF) technique in inverse kinematics was used to measure the g factors of the low lying 2{sub 1}{sup +}, 4{sub 1}{sup +}, and 2{sub 2}{sup +} states in {sup 106}Pd. The g factor of the 4{sub 1}{sup +} state was determined and the g(2{sub 1}{sup +}) and g(2{sub 2}{sup +}) factors were remeasured. The values of g(2{sub 1}{sup +}) and g(2{sub 2}{sup +}) had been determined earlier in integral perturbed angular correlation (IPAC) experiments and the value of the former served to calibrate the TF. The three g factors, g(2{sub 1}{sup +}), g(2{sub 2}{sup +}), and g(4{sub 1}{sup +}), agree with each other and with the collective Z/A value. The uncertainties in the g(2{sub 2}{sup +}) and g(4{sub 1}{sup +}) factors remain fairly large in spite of long measuring times because of the weak excitation of the two-phonon states. The lifetimes of the 2{sub 2}{sup +} and 4{sub 1}{sup +} states were newly determined from line-shape fits.

Guerdal, G.; Kumbartzki, G. J.; Benczer-Koller, N.; Sharon, Y. Y.; Zamick, L. [Department of Physics and Astronomy, Rutgers University, New Brunswick, New Jersey 08903 (United States); Robinson, S. J. Q. [Millsaps College, Jackson, Mississippi 39210 (United States); Ahn, T.; Casperson, R.; Heinz, A.; Ilie, G.; Qian, J.; Werner, V.; Williams, E.; Winkler, R. [A. W. Wright Nuclear Structure Laboratory, Yale University, New Haven, Connecticut 06520 (United States); McCarthey, D. [A. W. Wright Nuclear Structure Laboratory, Yale University, New Haven, Connecticut 06520 (United States); Department of Physics, University of Surrey, Guildford, Surrey (United Kingdom)

2010-12-15T23:59:59.000Z

316

The Role of Partial Crystallinity on Hydrogen Permeation in Fe–Ni–B–Mo Based Metallic Glass Membranes  

Science Conference Proceedings (OSTI)

A potentially exciting material for membrane separations are metallic glass materials due to their low cost, high elastic toughness and resistance to hydrogen embrittlement as compared to crystalline Pd-based membrane systems. However, at elevated temperatures and extended operation times structural changes including partial crystallinity may appear in these amorphous metallic systems. This study reports on the investigation of time and temperature dependent crystalline phase formation in conjunction with in situ crystallization/hydrogen permeation experiments at elevated temperatures. At temperatures near 400 C a FeNi crystalline phase appears as 22 vol.% inside the host amorphous matrix and the resulting composite structure remains stable over 3 h at temperature. The hydrogen permeation at 400 C of the partially crystalline material is similar to the fully amorphous material near 5 x 10{sup -9} mol H{sub 2}/m s Pa{sup 1/2}, while ambient temperature electrochemical permeation at 25 C revealed an order of magnitude decrease in the permeation of partially crystalline materials due to differences in the amorphous versus crystalline phase activation energy for hydrogen permeation.

Brinkman, K.; Su, D.; Fox, E.; Korinko, P.; Missimer, D.; Adams, T.

2011-08-15T23:59:59.000Z

317

MgO-Supported Cluster Catalysts with Pt-Ru Interactions Prepared from Pt3Ru6(CO)21(u3-H)(u-H)3  

Science Conference Proceedings (OSTI)

Bimetallic MgO-supported catalysts were prepared by adsorption of Pt{sub 3}Ru{sub 6}(CO){sub 21}({mu}{sub 3}-H)({mu}-H){sub 3} on porous MgO. Characterization of the supported clusters by infrared (IR) spectroscopy showed that the adsorbed species were still in the form of metal carbonyls. The supported clusters were decarbonylated by treatment in flowing helium at 300 C, as shown by IR and extended X-ray absorption fine structure (EXAFS) data, and the resulting supported PtRu clusters were shown by EXAFS spectroscopy to have metal frames that retained Pt-Ru bonds but were slightly restructured relative to those of the precursor; the average cluster size was almost unchanged as a result of the decarbonylation. These are among the smallest reported bimetallic clusters of group-8 metals. The decarbonylated sample catalyzed ethylene hydrogenation with an activity similar to that reported previously for {gamma}-Al{sub 2}O{sub 3}-supported clusters prepared in nearly the same way and having nearly the same structure. Both samples were also active for n-butane hydrogenolysis, with the MgO-supported catalyst being more active than the {gamma}-Al{sub 2}O{sub 3}-supported catalyst.

Chotisuwan,S.; Wittapyakun, J.; Lobo-Lapidus, R.; Gates, B.

2007-01-01T23:59:59.000Z

318

XPS study of Ni-Fe manganite thermistor material  

SciTech Connect

The resistivity of the as-fabricated thermistor material, nickel-iron-manganite, changes during initial aging in the temperature range of 150-300{degrees}C before becoming stable. X-ray photoelectron spectroscopy (XPS) was used to determine if any valency change or chemical shift of the cations or oxygen occurred after aging. The goal of the study was to identify any ionic changes that might affect thermistor stability. The only observed changes in 2p{sub 3/2} peaks due to aging were those related to Ni ions; the same peaks for Mn, Fe, and O remained unchanged. The changes in the Ni 2p{sub 3/2} peak may be related to: (a) the migration of Ni{sup 2+} ions from octahedral to tetrahedral sites, (b) subtle changes in the energy states of Ni{sup 2+} which promoted a more stable ionic structure, and/or (c) the presence of Ni{sup 3+} ions, some of which revert back to Ni{sup 2+}.

Braski, D.N. [Oak Ridge National Lab., TN (United States); Osborne, N.R. [Univ. of Dayton Research Institute, OH (United States); Zurbuchen, J.M. [Yellow Springs Instruments, Inc., OH (United States)

1995-03-01T23:59:59.000Z

319

Thermal Treatment of PtNiCo Electrocatalysts: Effects of Nanoscale Strain and Structure on the Activity and Stability for the Oxygen Reduction Reaction  

SciTech Connect

The ability to control the nanoscale size, composition, phase, and facet of multimetallic catalysts is important for advancing the design and preparation of advanced catalysts. This report describes the results of an investigation of the thermal treatment temperature on nanoengineered platinum-nickel-cobalt catalysts for oxygen reduction reaction, focusing on understanding the effects of lattice strain and surface properties on activity and stability. The thermal treatment temperatures ranged from 400 to 926 C. The catalysts were characterized by microscopic, spectroscopic, and electrochemical techniques for establishing the correlation between the electrocatalytic properties and the catalyst structures. The composition, size, and phase properties of the trimetallic nanoparticles were controllable by our synthesis and processing approach. The increase in the thermal treatment temperature of the carbon-supported catalysts was shown to lead to a gradual shrinkage of the lattice constants of the alloys and an enhanced population of facets on the nanoparticle catalysts. A combination of the lattice shrinkage and the surface enrichment of nanocrystal facets on the nanoparticle catalysts as a result of the increased temperature was shown to play a major role in enhancing the electrocatalytic activity for catalysts. Detailed analyses of the oxidation states, atomic distributions, and interatomic distances revealed a certain degree of changes in Co enrichment and surface Co oxides as a function of the thermal treatment temperature. These findings provided important insights into the correlation between the electrocatalytic activity/stability and the nanostructural parameters (lattice strain, surface oxidation state, and distribution) of the nanoengineered trimetallic catalysts.

B Wanjala; R Loukrakpam; J Luo; P Njoki; D Mott; C Zhong; M Shao; L Protsailo; T Kawamura

2011-12-31T23:59:59.000Z

320

Transformation Induced Fatigue of Ni-Rich NiTi Shape Memory Alloy Actuators  

E-Print Network (OSTI)

In this work the transformation induced fatigue of Ni-rich NiTi shape memory alloys (SMAs) was investigated. The aerospace industry is currently considering implementing SMA actuators into new applications. However, before any new applications can be put into production they must first be certified by the FAA. Part of this certification process includes the actuator fatigue life. In this study, as-received and polished at dogbone SMA specimens underwent transformation induced fatigue testing at constant loading. The constant applied loading ranged from 100 MPa to 200 MPa. Specimens were thermally cycled through complete actuation (above Af to below Mf ) by Joule heating and environmental cooling. There were three cooling environments studied: liquid, gaseous nitrogen and vortex cooled air. It was shown that polished specimens had fatigue lives that were two to four times longer than those of as-received specimens. Test environment was also found to have an effect on fatigue life. Liquid cooling was observed to be corrosive, while the gaseous nitrogen and vortex air cooling were observed to be non-corrosive. The two non-corrosive cooling environments performed similarly with specimen fatigue lives that were twice that of specimens fatigue tested in the corrosive cooling environment. Transformation induced fatigue testing of polished specimens in a non-corrosive environment at 200 MPa had an average fatigue life of 14400 actuation cycles; at 150 MPa the average fatigue life was 20800 cycles and at 100 MPa it was 111000 cycles. For all specimens constant actuation from the beginning of testing until failure was observed, without the need for training. Finally, a microstructural study showed that the Ni3Ti precipitates in the material were one of the causes of crack initiation and propagation in the actuators.

Schick, Justin Ryan

2009-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "ni pd pt" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Improved performance of NOx reduction by H2 and CO over a Pd/Al2O3 catalyst at low temperatures under lean-burn conditions  

E-Print Network (OSTI)

Improved performance of NOx reduction by H2 and CO over a Pd/Al2O3 catalyst at low temperatures 4 June 2004; accepted 6 June 2004 Available online 28 July 2004 Abstract Selective reduction of NOx of lean-burn vehicle exhaust. Macleod and Lambert [9] found that Pd/Al2O3 promotes lean NOx reduction

Gulari, Erdogan

322

(001) textured L1{sub 0}-FePt pseudo spin valve with TiN spacer  

Science Conference Proceedings (OSTI)

TiN was investigated as a potential spacer material in L1{sub 0}-FePt based pseudo spin valves (PSV). PSVs with the structure MgO/L1{sub 0}-Fe{sub 50}Pt{sub 50} (20 nm)/TiN (5 nm)/L1{sub 0}-Fe{sub 50}Pt{sub 50} (x nm) were fabricated, where x was varied from 5 to 20 nm. The highest giant magnetoresistance (GMR) ratio of 0.61% was obtained for the PSV with a top L1{sub 0}-FePt thickness of 20 nm. Contributions to the GMR arose from both the spin dependent scattering at the FePt/TiN interfaces and domain wall resistivity. Magnon magnetoresistance was also observed in the fabricated PSVs.

Ho, P. [Department of Materials Science and Engineering, National University of Singapore, 117576 Singapore (Singapore) and Data Storage Institute, Agency of Science, Technology and Research (A-STAR), 117608 Singapore (Singapore); Han, G. C. [Data Storage Institute, Agency of Science, Technology and Research (A-STAR), 117608 Singapore (Singapore); He, K. H.; Chow, G. M.; Chen, J. S. [Department of Materials Science and Engineering, National University of Singapore, 117576 Singapore (Singapore)

2011-12-19T23:59:59.000Z

323

Synthesis of graphene-based Pt nanoparticles by a one-step in situ plasma approach under mild conditions  

Science Conference Proceedings (OSTI)

Herein, a one-step in situ plasma approach to synthesize the highly dispersed Pt nanoparticles on graphene under mild conditions is reported. The graphene oxide (GO) was transformed into graphene and H{sub 2}PtCl{sub 6} was simultaneously transformed into Pt nanoparticles under argon plasma conditions. The synthesized graphene-based Pt nanoparticles were characterized by scanning electron microscopy, atomic force microscopy, x-ray diffraction, and Fourier transform infrared spectroscopy. The analysis showed that the Pt nanoparticles were deposited on graphene as a form of face-centered cubical structure and the oxygen groups on graphene oxide were partially removed. The results of x-ray photoelectron spectroscopy analysis further confirmed the results.

Wang Qi; Song Mingming; Chen Changlun; Wei Yu; Zuo Xiao; Wang Xiangke [Key Laboratory of Novel Thin Film Solar Cells, Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei 230031 (China)

2012-07-16T23:59:59.000Z

324

Synthesis of Zr Doped NiO Layers on NiSi2 Linling Gu/Si-MCP Structures for Supercapacitors  

Science Conference Proceedings (OSTI)

Three-dimensional super capacitors consisting of NiSi2/silicon micro channel plates (MCPs) with Zr doped NiO layers have been fabricated. The silicon MCPs produced by electrochemical etching is utilized as a backbone of the 3D structure. Nickle layer ... Keywords: Zr doped NiO, Electrochemical properties, Silicon microchannel plate

Linling Gu; Tao Liu; Fei Wang; Shaohui Xu; Lianwei Wang; Paul K. Chu

2012-04-01T23:59:59.000Z

325

DIFFUSION OF H THROUGH PD MEMBRANES EFFECTS OF NON-IDEALITY ON DH AND ED  

DOE Green Energy (OSTI)

H diffusion constants, D{sub H}, have been obtained from steady-state fluxes across Pd membranes with the downstream side maintained at p{sub H2} {approx} 0. Good linearity of plots of H flux versus (1/d), where d is the thickness, attests to the H permeation being bulk diffusion controlled in this temperature (423 to 523K) and p{sub H2} range ({le} 0.2 MPa). D{sub H} values have been determined at constant p{sub up} and also at constant (H/Pd)=r conditions. H fluxes through Pd membranes with three different surface treatments have been investigated (polished (un-oxidized), oxidized, and palladized) in order to determine the effects of these pretreatments. The palladized and oxidized membranes give similar D{sub H} values but the polished membranes give values about 12% lower. For diffusion in a concentration gradient D{sub H}*(c{sub H}/RT)(d{mu}{sub H}/dx) is the more proper description, where c{sub H} is the H concentration, rather than D{sub H}(dc{sub H}/dx) where D{sub H} and D{sub H}* are the concentration-dependent and independent diffusion constants. D{sub H}* can be obtained from D{sub H} using the thermodynamic factor, D{sub H}(r) = D{sub H}*({partial_derivative}lnp{sub H2}{sup 1/2}/{partial_derivative}lnr){sub T} = D{sub H}*f(r). In the commonly employed situation where there is a large difference in concentrations between the upstream and downstream sides of a membrane, the thermodynamic factor varies with distance through the membrane and this should be allowed for in obtaining D{sub H}*. Procedures are given and utilized for using D{sub H}(c{sub H}) to determine D{sub H}* values when there is a large concentration gradient through the membrane. Activation energies for diffusion, E{sub D}(c{sub H}), have been determined. E{sub D} is found to increase with c{sub H} which can be attributed to the thermodynamic factor. D{sub H}* values have been found to increase with H content.

Shanahan, K

2007-03-09T23:59:59.000Z

326

(ME = Co, Ni and Cu) Materials: Metathesis Reaction  

Science Conference Proceedings (OSTI)

Presentation Title, D15: Facile Synthesis and Electrical Properties of ... hydrated bismuth and metal nitrates as required by stoichiometry and milling them .... of Pt Nanoparticles on ITO Substrate: Morphological Effect on Ammonia Oxidation ... E20: Study on Cavitation Erosion Mechanism in Friction Stir Processed Mild Steel .

327

Acceptability of Four Transformer Top-Oil Thermal Models: Pt. 2: Comparing Metrics  

E-Print Network (OSTI)

1 Acceptability of Four Transformer Top-Oil Thermal Models: Pt. 2: Comparing Metrics Lida Jauregui transformer top-oil thermal models are examined vis-à-vis training with measured data. Acceptability is unacceptable for model identification purposes. The linear top-oil model is acceptable for FOFA transformers

328

Nanopore Patterned Pt Array Electrodes for Triple Phase Boundary Study in Low Temperature SOFC  

E-Print Network (OSTI)

Nanopore Patterned Pt Array Electrodes for Triple Phase Boundary Study in Low Temperature SOFC structural integrity and thermal stability at the solid oxide fuel cell SOFC operating temperature of 450, Meeting of the Society, October 4­9, 2009. Solid oxide fuel cells SOFCs are efficient energy conversion

Cui, Yi

329

Table PT2. Energy Production Estimates in Trillion Btu, Ohio, 1960 ...  

U.S. Energy Information Administration (EIA)

Table PT2. Energy Production Estimates in Trillion Btu, Ohio, 1960 - 2011 1960 796.6 36.9 31.3 0.0 NA 37.0 37.0 901.9 1961 756.0 37.3 32.7 0.0 NA 36.4 36.4 862.4

330

Overview of Hard processes at RHIC: high-pt light hadron and charm production  

E-Print Network (OSTI)

An overview of the experimental results on high-pt light hadron production and open charm production is presented. Data on particle production in elementary collisions are compared to next-to-leading order perturbative QCD calculations. Particle production in Au+Au collisions is then compared to this baseline.

M. van Leeuwen

2004-12-10T23:59:59.000Z

331

Studies of switching field and thermal energy barrier distributions in a FePt nanoparticle system  

E-Print Network (OSTI)

Studies of switching field and thermal energy barrier distributions in a FePt nanoparticle system X dependence of the thermal stability factor, the width of the thermal energy barrier distribution- ropy energy distribution and the interaction and the thermal energy barrier distribution determined

Laughlin, David E.

332

Spectroscopic study of tetradecyltrimethylammonium bromide Pt-C14TAB nanoparticles: Structure and Stability  

Science Conference Proceedings (OSTI)

The vibrational spectra of platinum nanoparticles (12 nm) capped with tetradecyltrimethylammonium bromide, C{sub 14}TAB, were investigated by Fourier transform infrared (FTIR) spectroscopy. We have shown that the thermal decay of Pt-C{sub 14}TAB nanoparticles in N{sub 2}, H{sub 2} and O{sub 2} atmospheres leads to the release of hydrocarbon chain of surfactant and the formation of strongly bonded layer of ammonium cations on the platinum surface. The platinum atoms accessible to CO chemisorptions were not reducible by hydrogen in the temperature ranging from 30 C to 200 C. A FTIR spectrum of C{sub 14}TAB adsorbed on Pt nanoparticles dramatically perturbed as compared with pure C{sub 14}TAB. New intense and broad bands centered at 1450 cm{sup -1} and 760 cm{sup -1} are making their appearance in Pt-C{sub 14}TAB. It may be speculated, that new bands are result of coupling between conducting electrons of Pt and molecular vibrations of adsorbed C{sub 14}TAB and as a consequence specific vibrational modes of ammonium cation transformed into electron-vibrational modes.

Borodko, Y.; Jones, L.; Frei, H.; Somorjai, G.

2009-01-09T23:59:59.000Z

333

Photodeposition of Pt on Colloidal CdS and CdSe/CdS Semiconductor Nanostructures  

E-Print Network (OSTI)

on Colloidal CdS and CdSe/CdS Semiconductor Nanostructuresof Pt on colloidal CdS and CdSe/CdS core/shell nanocrystals.photoexcitation of CdS and CdSe/CdS in the presence of an

Dukovic, Gordana

2008-01-01T23:59:59.000Z

334

Manipulation and patterning of the surface hydrogen concentrationon Pd(111) electric fields  

DOE Green Energy (OSTI)

Modification of the structure of materials at the nanoscale level is one goal of current nanoscience research. For example, by purposefully modifying the spatial distribution of adsorbates one could control the rate of chemical reactions on a local scale. Here we show how this can be accomplished in the case of H on Pd(111) through the application of local electric fields. Hydrogen adsorption on the platinum group metals is particularly interesting because these metals are used as catalysts in a variety of industrial processes, including hydrogenation and dehydrogenation reactions. Electric fields on surfaces are also of primary interest in electrochemistry where despite the considerable amount of experimental and theoretical work done to date, there still remains more work to be done before a clear understanding of phenomena at the atomic scale can be accomplished.

Mitsui, T.; Fomin, E.; Ogletree, D.F.; Salmeron, M.; Nilekar,A.U.; Mavrikakis, M.

2007-05-10T23:59:59.000Z

335

Surface Segregation in a PdCu Alloy Hydrogen Separation Membrane  

DOE Green Energy (OSTI)

Separation of hydrogen from mixed gas streams is an important step for hydrogen generation technologies, including hydrocarbon reforming and coal/biomass gasification. Dense palladium-based membranes have received significant attention for this application because of palladium’s ability to dissociatively adsorb molecular hydrogen at its surface for subsequent transport of hydrogen atoms through its bulk. Alloying palladium with minor components, like copper, has been shown to improve both the membrane’s structural characteristics and resistance to poisoning of its catalytic surface [1]. Surface segregation—a composition difference between the bulk material and its surface—is common in alloys and can affect important surface processes. Rational design of alloy membranes requires that surface segregation be understood, and possibly controlled. In this work, we examine surface segregation in a polycrystalline Pd70Cu30 hydrogen separation membrane as a function of thermal treatment and adsorption of hydrogen sulfide.

Miller, J.B.; Matranga, C.S.; Gellman, A.J.

2007-06-01T23:59:59.000Z

336

001 A Novel Protocol for Synthesis of Pd/TiO2/SiO2 Nanocomposite ...  

Science Conference Proceedings (OSTI)

... with an aqueous solution of nitric acid are mixed with Pd.The latter was previously reduced via a ... 008 Effect of Crystallinity on Dissolution Properties of Plasma Sprayed ... 015 Highly Sensitive Determination of Ascorbic Acid over Polyaniline ... of Strontium Sulfualuminate Sr4Al6O12SO4 with Molten Aluminum Alloys.

337

Synthesis and study of ligands for Pd-catalyzed C-O and C-N coupling  

E-Print Network (OSTI)

A new ligand, AdBrettPhos, was synthesized and its use, along with tBuBrettPhos, in C-O coupling reactions at low temperatures was investigated. Using Pd catalysts containing these ligands, electron-neutral aryl bromides ...

Davis, Nicole R

2009-01-01T23:59:59.000Z

338

Probing the nuclides {sup 102}Pd, {sup 106}Cd, and {sup 144}Sm for resonant neutrinoless double-electron capture  

SciTech Connect

The Q values for double-electron capture in {sup 102}Pd, {sup 106}Cd, and {sup 144}Sm have been measured by Penning-trap mass spectrometry. The results exclude at present all three nuclides from the list of suitable candidates for a search for resonant neutrinoless double-electron capture.

Goncharov, M.; Blaum, K.; Eliseev, S. [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany); Block, M.; Herfurth, F.; Minaya Ramirez, E. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Planckstrasse 1, D-64291 Darmstadt (Germany); Droese, C.; Schweikhard, L. [Institut fuer Physik, Ernst-Moritz-Arndt-Universitaet, D-17487 Greifswald (Germany); Novikov, Yu. N. [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany); Petersburg Nuclear Physics Institute, Gatchina, RU-188300 St. Petersburg (Russian Federation); Department of Physics, St. Petersburg State University, RU-198504 St. Petersburg (Russian Federation); Zuber, K. [Institut fuer Kern- und Teilchenphysik, Technische Universitaet, D-01069 Dresden (Germany)

2011-08-15T23:59:59.000Z

339

The Role of -Al2O3 Single Crystal Support to Pt Nanoparticles Construction Zhongfan Zhang*, Long Li*, Lin-lin Wang**, Sergio I. Sanchez***, Qi Wang****,  

E-Print Network (OSTI)

The Role of -Al2O3 Single Crystal Support to Pt Nanoparticles Construction Zhongfan Zhang*, Long Li the preparation of a model Pt/-Al2O3 catalyst and its characterization by a cross-sectional high-resolution electron microscopy (XHREM) method. Pt/-Al2O3 is the most important technologically-relevant heterogeneous

Frenkel, Anatoly

340

Modified COMS Plaques for {sup 125}I and {sup 103}Pd Iris Melanoma Brachytherapy  

Science Conference Proceedings (OSTI)

Purpose: Novel plaques are used to treat iris melanoma at the Mayo Clinic Rochester. The plaques are a modification of the Collaborative Ocular Melanoma Study (COMS) 22 mm plaque design with a gold alloy backing, outer lip, and silicone polymer insert. An inner lip surrounds a 10 mm diameter cutout region at the plaque center. Plaques span 360{sup o}, 270{sup o}, and 180{sup o} arcs. This article describes dosimetry for these plaques and others used in the treatment of anterior eye melanomas. Methods and Materials: The EGSnrc user-code BrachyDose is used to perform Monte Carlo simulations. Plaques and seeds are fully modeled. Three-dimensional dose distributions for different plaque models, TG-43 calculations, and {sup 125}I (model 6711) and {sup 103}Pd (model 200) seeds are compared via depth-dose curves, tabulation of doses at points of interest, and isodose contours. Results: Doses at points of interest differ by up to 70% from TG-43 calculations. The inner lip reduces corneal doses. Matching plaque arc length to tumor extent reduces doses to eye regions outside the treatment area. Maintaining the same prescription dose, {sup 103}Pd offers lower doses to critical structures than {sup 125}I, with the exception of the sclera adjacent to the plaque. Conclusion: The Mayo Clinic plaques offer several advantages for anterior eye tumor treatments. Doses to regions outside the treatment area are significantly reduced. Doses differ considerably from TG-43 predictions, illustrating the importance of complete Monte Carlo simulations. Calculations take a few minutes on a single CPU, making BrachyDose sufficiently fast for routine clinical treatment planning.

Thomson, Rowan M., E-mail: rthomson@physics.carleton.c [Ottawa Carleton Institute of Physics, Carleton University, Ottawa, ON (Canada); Furutani, Keith M.; Pulido, Jose S.; Stafford, Scott L. [Mayo Clinic College of Medicine, Rochester, MN (United States); Rogers, D.W.O. [Ottawa Carleton Institute of Physics, Carleton University, Ottawa, ON (Canada)

2010-11-15T23:59:59.000Z

Note: This page contains sample records for the topic "ni pd pt" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

NiO as a peculiar support for metal nanoparticles in polyols oxidation  

SciTech Connect

The peculiar influence of a NiO support was studied by preparing gold catalysts supported on NiO(1-x) TiO2(x) mixed oxides. PVA protected Au nanoparticles showed high activity when supported on NiO for the selective oxidation of glycerol and ethan-1,2-diol. A detailed characterization of the resulting Au catalysts revealed a preferential deposition of the metal nanoparticles on the NiO phase. However, the activity of Au on NiO(1-x)-TiO2(x) decreased with respect to pure NiO and the selectivity evolved with changes to the support.

Villa, Alberto [Universita di Milano, Italy; Veith, Gabriel M [ORNL; Ferri, Davide [EMPA, Laboratory for High Performance Ceramics, Duebendorf, Switzerland; Weidenkaff, Anke [EMPA, Laboratory for High Performance Ceramics, Duebendorf, Switzerland; Perry, Kelly A [ORNL; Campisi, Sebastiano [University of Milan and INFN, Milano, Italy; Prati, Laura [Universita di Milano, Italy

2013-01-01T23:59:59.000Z

342

Diffusion bonding of commercially pure Ni using Cu interlayer  

Science Conference Proceedings (OSTI)

The concentration dependence of diffusivity in a multi-component diffusion system makes it complicated to predict the concentration profiles of diffusing species. This so called chemical diffusivity can be expressed as a function of thermodynamic and kinetic data. DICTRA software can calculate the concentration profiles using appropriate mobility and thermodynamic data. It can also optimize the diffusivity data using experimental diffusivity data. Then the optimized diffusivity data is stored as mobility data which is a linear function of temperature. In this work, diffusion bonding of commercially pure Ni using Cu interlayers is reported. The mobility parameters of Ni-Cu alloy binary systems were optimized using DICTRA/Thermocalc software from the available self-, tracer and chemical diffusion coefficients. The optimized mobility parameters were used to simulate concentration profiles of Ni-Cu diffusion joints using DICTRA/Thermocalc software. The calculated and experimental concentration profiles agreed well at 1100 Degree-Sign C. Agreement between the simulated and experimental profiles was less good at 1050 Degree-Sign C due to the grain boundary contribution to the overall diffusion. - Highlights: Black-Right-Pointing-Pointer The concentration profiles of Cu in Ni-Cu diffusion joints are modeled. Black-Right-Pointing-Pointer Interdiffusion coefficients in Ni-Cu system are optimized. Black-Right-Pointing-Pointer Optimized interdiffusion coefficients are expressed as mobility parameters. Black-Right-Pointing-Pointer Simulated profiles are comparable with experimental profiles.

Rahman, A.H.M.E., E-mail: a.rahman@my.und.edu; Cavalli, M.N.

2012-07-15T23:59:59.000Z

343

Mitigation of Sulfur Poisoning of Ni/Zirconia SOFC Anodes by Antimony and Tin  

Science Conference Proceedings (OSTI)

Surface Ni/Sb and Ni/Sb alloys were found to efficiently minimize the negative effects of sulfur on the performance of Ni/zirconia anode-supported solid oxide fuel cells (SOFC). Prior to operating on fuel gas containing low concentrations of H2S, the nickel/zirconia anodes were briefly exposed to antimony or tin vapor, which only slightly affected the SOFC performance. During the subsequent exposures to 1 and 5 ppm H2S, increases in anodic polarization losses were minimal compared to those observed for the standard nickel/zirconia anodes. Post-test XPS analyses showed that Sb and Sn tended to segregate to the surface of Ni particles, and further confirmed a significant reduction of adsorbed sulfur on the Ni surface in Ni/Sn and Ni/Sb samples compared to the Ni. The effect may be the result of weaker sulfur adsorption on bimetallic surfaces, adsorption site competition between sulfur and Sb or Sn on Ni, or other factors. The use of dilute binary alloys of Ni-Sb or Ni-Sn in the place of Ni, or brief exposure to Sb or Sn vapor, may be effective means to counteract the effects of sulfur poisoning in SOFC anodes and Ni catalysts. Other advantages, including suppression of coking or tailoring the anode composition for the internal reforming, are also expected.

Marina, Olga A.; Coyle, Christopher A.; Engelhard, Mark H.; Pederson, Larry R.

2011-02-28T23:59:59.000Z

344

Spin-Orbit Strength Driven Crossover between Intrinsic and Extrinsic Mechanisms of the Anomalous Hall Effect in the Epitaxial L10-Ordered Ferromagnets FePd and FePt  

E-Print Network (OSTI)

, APEEM ¼ Iþ�I� IþþI� . For constant absolute value of the magnetic moments, APEEM is proportional

Kuch, Wolfgang

345

Superlubricity through graphene multilayers between Ni(111) surfaces  

E-Print Network (OSTI)

A single graphene layer placed between two parallel Ni(111) surfaces screens the strong attractive force and results in a significant reduction of adhesion and sliding friction. When two graphene layers are inserted, each graphene is attached to one of the metal surfaces with a significant binding and reduces the adhesion further. In the sliding motion of these surfaces the transition from stick-slip to continuous sliding is attained, whereby non-equilibrium phonon generation through sudden processes is suppressed. The adhesion and corrugation strength continues to decrease upon insertion of the third graphene layer and eventually saturates at a constant value with increasing number of graphene layers. In the absence of Ni surfaces, the corrugation strength of multilayered graphene is relatively higher and practically independent of the number of layers. Present first-principles calculations reveal the superlubricant feature of graphene layers placed between pseudomorphic Ni(111) surfaces, which is achieved t...

Cahangirov, S; Özçelik, V Ongun

2013-01-01T23:59:59.000Z

346

Photodeposition of Pt on Colloidal CdS and CdSe/CdS Semiconductor Nanostructures  

DOE Green Energy (OSTI)

Semiconductor photocatalysis has been identified as a promising avenue for the conversion of solar energy into environmentally friendly fuels, most notably by the production of hydrogen from water.[1-5] Nanometer-scale materials in particular have attracted considerable scientific attention as the building blocks for light-harvesting applications.[6,7] Their desirable attributes include tunability of the optical properties with size, amenability to relatively inexpensive low-temperature processing, and a high degree of synthetic sophistication leading to increasingly complex and multi-functional architectures. For photocatalysis in particular, the high surface-to-volume ratios in nanoscale materials should lead to an increased availability of carriers for redox reactions on the nanoparticle surface. Recombination of photoexcited carriers directly competes with photocatalytic activity.[3] Charge separation is often achieved with multi-component heterostructures. An early example is the case of TiO2 powders functionalized with Pt and RuO2 particles, where photoexcited electrons are transferred to Pt (the reduction site) and holes to RuO2 (the oxidation site).[8] More recently, many colloidally synthesized nanometer-scale metal-semiconductor heterostructures have been reported.[7,9,10] A majority of these structures are made by thermal methods.[7,10] We have chosen to study photochemical formation of metal-semiconductor heterostructures. The detailed understanding of the mechanisms involved in photodeposition of metals on nanometer-scale semiconductors is necessary to enable a high degree of synthetic control. At the same time, because the results of metal deposition can be directly observed by electron microscopy, it can be used to understand how factors such as nanocrystal composition, shape, carrier dynamics, and surface chemistry influence the photochemical properties of semiconductor nanocrystals. In this communication, we report on the photodeposition of Pt on colloidal CdS and CdSe/CdS core/shell nanocrystals. Among the II-VI semiconductors, CdS is of particular interest because it has the correct band alignment for water photolysis[2] and has been demonstrated to be photocatalytically active.[11-16] We have found that the photoexcitation of CdS and CdSe/CdS in the presence of an organometallic Pt precursor leads to deposition of Pt nanoparticles on the semiconductor surface. Stark differences are observed in the Pt nanoparticle location on the two substrates, and the photodeposition can be completely inhibited by the modification of the semiconductor surface. Our results suggest that tuning of the semiconductor band structure, spatial organization and surface chemistry should be crucial in the design of photocatalytic nanostructures.

Dukovic, Gordana; Merkle, Maxwell G.; Nelson, James H.; Hughes, Steven M.; Alivisatos, A. Paul

2008-08-06T23:59:59.000Z

347

CoNiFe Alloy Powder Synthesis by High Energy Milling  

Science Conference Proceedings (OSTI)

CoNiFe alloy powder was synthesized by high energy milling of mixtures of Co, Ni and Fe powder as a bulk processing method for producing powder. A milling ...

348

The Effect of Pellet Geometry on The Specific Activity of Ni-63.  

E-Print Network (OSTI)

?? 63Ni [Nickel-63] is routinely produced at HFIR with a specific activity of ~15 Ci/g [Curies/gram] by irradiating highly enriched stable 62Ni [Nickel-62] (86.31 %)… (more)

Walsh, Spenser Riley

2013-01-01T23:59:59.000Z

349

An in situ X-ray absorption spectroscopy investigation of the effect of Sn additions to carbon-supported Pt electrocatalysts: Part 1  

Science Conference Proceedings (OSTI)

Carbon-supported platinum (Pt/C) with an adsorbed layer of underpotential deposited (upd) Sn is a much better catalyst for the methanol oxidation reaction (MOR) than a carbon-supported platinum-tin (PtSn/C) alloy. In situ X-ray absorption (XAS) was used to determine the differences in the effects that the two methods of Sn addition have on the electronic properties and the structural properties of the catalyst. X-ray diffraction and XAS at the Pt L{sub 3} and L{sub 2} edges indicate that the PtSn/C catalyst has a Pt{sub 3}Sn L1{sub 2} structure, and alloying with Sn causes partial filling of the Pt d band vacancies and an increase in the Pt-Pt bond distance from 2.77 to 2.8 {angstrom}. However, upd Sn does not perturb Pt structurally or electronically. XAS at the Sn K edge indicates that both the upd Sn on Pt/C and the surface Sn on PtSn/C are associated with oxygenated species at all potentials, and that the nature and strength of the Sn-O bonds are potential dependent. The differences in the activity of the two catalysts for the MOR are due to the effects of alloying on the Pt electronic structure that inhibit the ability of the Pt to adsorb methanol and dissociate C-H bonds. The ability of PtSn/C to adsorb oxygen at low potentials enhances its activity for CO oxidation.

Mukerjee, S.; McBreen, J. [Brookhaven National Lab., Upton, NY (United States). Dept. of Applied Science

1999-02-01T23:59:59.000Z

350

Effect of amorphous Mg{sub 50}Ni{sub 50} on hydriding and dehydriding behavior of Mg{sub 2}Ni alloy  

SciTech Connect

Composite Mg{sub 2}Ni (25 wt.%) amorphous Mg{sub 50}Ni{sub 50} was prepared by mechanical milling starting with nanocrystalline Mg{sub 2}Ni and amorphous Mg{sub 50}Ni{sub 50} powders, by using a SPEX 8000 D mill. The morphological and microstructural characterization of the powders was performed via scanning electron microscopy and X-ray diffraction. The hydriding characterization of the composite was performed via a solid gas reaction method in a Sievert's-type apparatus at 363 K under an initial hydrogen pressure of 2 MPa. The dehydriding behavior was studied by differential thermogravimetry. On the basis of the results, it is possible to conclude that amorphous Mg{sub 50}Ni{sub 50} improved the hydriding and dehydriding kinetics of Mg{sub 2}Ni alloy upon cycling. A tentative rationalization of experimental observations is proposed. - Research Highlights: {yields} First study of the hydriding behavior of composite Mg{sub 2}Ni (25 wt.%) amorphous Mg{sub 50}Ni{sub 50}. {yields} Microstructural characterization of composite material using XRD and SEM was obtained. {yields} An improved effect of Mg{sub 50}Ni{sub 50} on the Mg{sub 2}Ni hydriding behavior was verified. {yields} The apparent activation energy for the hydrogen desorption of composite was obtained.

Guzman, D., E-mail: danny.guzman@uda.cl [Departamento de Ingenieria en Metalurgia, Facultad de Ingenieria, Universidad de Atacama y Centro Regional de Investigacion y Desarrollo Sustentable de Atacama (CRIDESAT), Av. Copayapu 485, Copiapo (Chile); Ordonez, S. [Departamento de Ingenieria Metalurgica, Facultad de Ingenieria, Universidad de Santiago de Chile, Av. Lib. Bernardo O'Higgins 3363, Santiago (Chile); Fernandez, J.F.; Sanchez, C. [Departamento de Fisica de Materiales, Facultad de Ciencias, Universidad Autonoma de Madrid, Cantoblanco 28049, Madrid (Spain); Serafini, D. [Departamento de Fisica, Facultad de Ciencias, Universidad de Santiago de Chile and Center for Interdisciplinary Research in Materials, CIMAT, Av. Lib. Bernardo O'Higgins 3363, Santiago (Chile); Rojas, P.A. [Escuela de Ingenieria Mecanica, Facultad de Ingenieria, Av. Los Carrera 01567, Quilpue, Pontificia Universidad Catolica de Valparaiso, PUCV (Chile); Aguilar, C. [Departamento de Ingenieria Metalurgica y Materiales, Universidad Tecnica Federico Santa Maria, Av. Espana 1680, Valparaiso (Chile); Tapia, P. [Departamento de Ingenieria en Metalurgia, Facultad de Ingenieria, Universidad de Atacama, Av. Copayapu 485, Copiapo (Chile)

2011-04-15T23:59:59.000Z

351

Single-step Precipitation of Ni Nanoparticle Catalyst on Zeolite and ...  

Science Conference Proceedings (OSTI)

Abstract Scope, Ni nanoparticle catalyst was prepared on zeolite (pores size: 2 production rate from the methanol stream reforming reaction ...

352

(Electronic structure and reactivities of transition metal clusters)  

DOE Green Energy (OSTI)

The following are reported: theoretical calculations (configuration interaction, relativistic effective core potentials, polyatomics, CASSCF); proposed theoretical studies (clusters of Cu, Ag, Au, Ni, Pt, Pd, Rh, Ir, Os, Ru; transition metal cluster ions; transition metal carbide clusters; bimetallic mixed transition metal clusters); reactivity studies on transition metal clusters (reactivity with H{sub 2}, C{sub 2}H{sub 4}, hydrocarbons; NO and CO chemisorption on surfaces). Computer facilities and codes to be used, are described. 192 refs, 13 figs.

Not Available

1992-01-01T23:59:59.000Z

353

[Electronic structure and reactivities of transition metal clusters  

DOE Green Energy (OSTI)

The following are reported: theoretical calculations (configuration interaction, relativistic effective core potentials, polyatomics, CASSCF); proposed theoretical studies (clusters of Cu, Ag, Au, Ni, Pt, Pd, Rh, Ir, Os, Ru; transition metal cluster ions; transition metal carbide clusters; bimetallic mixed transition metal clusters); reactivity studies on transition metal clusters (reactivity with H{sub 2}, C{sub 2}H{sub 4}, hydrocarbons; NO and CO chemisorption on surfaces). Computer facilities and codes to be used, are described. 192 refs, 13 figs.

Not Available

1992-08-01T23:59:59.000Z

354

Tracking down localized modes in PT-symmetric Hamiltonians under the influence of a competing nonlinearity  

E-Print Network (OSTI)

The relevance of parity and time reversal (PT)-symmetric structures in optical systems is known for sometime with the correspondence existing between the Schrodinger equation and the paraxial equation of diffraction where the time parameter represents the propagating distance and the refractive index acts as the complex potential. In this paper, we systematically analyze a normalized form of the nonlinear Schrodinger system with two new families of PT-symmetric potentials in the presence of competing nonlinearities. We generate a class of localized eigenmodes and carry out a linear stability analysis on the solutions. In particular, we find an interesting feature of bifurcation charaterized by the parameter of perturbative growth rate passing through zero where a transition to imaginary eigenvalues occurs.

Bijan Bagchi; Subhrajit Modak; Prasanta K. Panigrahi

2013-07-27T23:59:59.000Z

355

High-Yield Solvothermal Formation of Magnetic CoPt Alloy Nanowires  

SciTech Connect

One-dimensional (1D) magnetic nanomaterials have attracted much attention recently because of their applications in magnetic recording and spintronics. Nevertheless, it remains a challenge to prepare free-standing magnetic nanowires in high yield. This Communication reports the successful high-yield synthesis of an interesting 1D ferromagnetic CoPt alloy by direct decomposition of platinum acetylacetonate and cobalt carbonyl compound in ethylenediamine solvent through a solvothermal reaction. The CoPt alloy nanowires obtained have a tunable diameter of 10-50 nm and a length along the longitudinal axis of up to several microns, depending on crystallization temperature and reaction time. A unique formation mechanism involving coarsening and ripening under solvothermal conditions was discovered. This research opens new opportunities in synthesizing nanomaterials through low-temperature solvothermal processes.

Zhang, Zongtao [ORNL; Blom, Douglas Allen [ORNL; Gai, Zheng [ORNL; Thompson, James R [ORNL; Shen, Jian [ORNL; Dai, Sheng [ORNL

2003-01-01T23:59:59.000Z

356

Durability of Low Pt Fuel Cells Operating at High Power Density  

NLE Websites -- All DOE Office Websites (Extended Search)

SPIRE Program Kickoff SPIRE Program Kickoff Topic 3A. Cell Degradation Studies / Degradation Studies Durability of Low Pt Fuel Cells Operating at High Power Density US DOE Fuel Cell Projects Kickoff Meeting DOE Award: DE-EE0000469 October 1 st , 2009 Program Objectives The objective of this program is to study and identify strategies to assure durability of fuel cells designed to meet DOE cost targets. Technical Barriers Barrier Approach Strategy A. Durability Reinforced, Stabilized Membrane MEA Partner Durability-Enhanced Electrodes Electrocatalyst/MEA Partner Optimized Operating Conditions Parametric model & experimental studies B. Cost Low Pt Loadings (0.2 mg/cm 2 ) Electrocatalyst/MEA Partner High Power Density (>1.0W/cm 2 ) Open Flowfield Stack Metallic Stack Architecture Incumbent Derivative

357

DOE-STD-1073-93-Pt. 1; DOE Standard Guide for Operational Configuration Management Program  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

3-93-Pt.2 3-93-Pt.2 November 1993 DOE STANDARD GUIDE FOR OPERATIONAL CONFIGURATION MANAGEMENT PROGRAM Including the Adjunct Programs of Design Reconstitution and Material Condition and Aging Management PART ll U.S. Department of Energy AREA CMAN Washington, D.C. 20585 DISTRIBUTION STATEMENT A: Approved for public release; distribution Is unlimited. This document has been reproduced directly from the best available copy. Available to DOE and DOE contractors from the Office of Scientific and Technical Information, P.O. Box 62, Oak Ridge, TN 37831; (615) 576-8401. Available to the public from the National Technical Information Service, U.S. Department of Commerce, 5285 Port Royal Rd., Springfield, VA 22161. Order No. DE94005408 i CONTENTS FOREWORD .

358

Irradiation-controlled giant magnetoresistance of PtMn-based spin valve  

Science Conference Proceedings (OSTI)

He{sup +}-ion irradiation resulted in the direct ordering of PtMn without postannealing. Samples were irradiated with 2 MeV He{sup +} ions and a beam current of 1.08 {mu}A/cm{sup 2} such that the corresponding surface temperature was 190 deg. C. The exchange bias direction was set in situ during irradiation in a field of 900 Oe. A high giant magnetoresistance (GMR) ratio of 11% was obtained in PtMn-based spin valves after He{sup +} irradiation. The GMR is completely eliminated after it is irradiated with oxygen ions at 42 keV. Combining He{sup +} with oxygen-ion irradiation can provide magnetic patterning for GMR sensors.

Huang, S.-H.; Lai, C.-H.; Chiang, C. C.; Yang, C.-H. [Department of Materials Science and Engineering, National Tsing Huang University, 101, Section 2, Kuang Fu Road, Hsinchu, Taiwan 30013 (China)

2006-04-15T23:59:59.000Z

359

First principles study of effect of surface structure on chemical activity of Pt electrocatalysts in fuel cells  

E-Print Network (OSTI)

To facilitate commercialization of fuel cell systems as alternative energy device, the enhancement of Pt electrocatalysts activity is one of the most challenging issues. The first step to the solution is elucidating ...

Han, Byungchan

2008-01-01T23:59:59.000Z

360

Place-exchange mechanism of Pt (111) oxidation/reduction as observed by synchrotron X-ray scattering  

DOE Green Energy (OSTI)

Structural changes in the Pt(111) single crystal surface associated with incipient electrochemical oxidation/reduction were studied by {ital in}{ital situ} synchrotron x-ray reflectivity. It was shown that lifting of Pt atoms of the surface layer occurs, substantiating the long-standing hypothesis of a place-exchange mechanism for solution/metal interface oxidation. It was also shown that, for a charge transfer of {approx_lt}1.7 e{sup -}/Pt atom, the initially flat surface structure could be recovered by electrochemical reduction. In constrast, the surface was irreversibly roughened for amounts of charge transfer exceeding {approx}1.7 e{sup -}/Pt, but the roughening involved only the atoms in the top layer of the original flat surface. A detailed mechanism is proposed for the place-exchange mechanism and the subsequent roughening of the electrode surface.

You, H.; Nagy, Z.; Zurawski, D.J.; Chiarello, R.P.

1996-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "ni pd pt" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Steam effect on NOx reduction over lean NOx trap Pt–BaO/Al2O3 ...  

Science Conference Proceedings (OSTI)

Compared to dry atmosphere, steam promoted NOx reduction; however, under ... stored NOx over Pt–BaO/Al2O3 suggest that steam causes NH3 formation over ...

362

Synthesis, Activity and Durability of Pt Nanoparticles Supported on Multi-walled Carbon Nanotubes for Oxygen Reduction  

E-Print Network (OSTI)

Carbon nanotube supported metal nanoparticles (NPs) have attracted considerable attention due to their great potential for heterogeneous catalysis. In this paper, surfactant-free and well dispersed platinum (Pt) NPs supported ...

Massachusetts Institute of Technology. Dept. of Chemistry; Massachusetts Institute of Technology. Dept. of Mechanical Engineering; Massachusetts Institute of Technology. Dept. of Materials Science and Engineering; Sheng, Wenchao; Lee, Seung Woo; Crumlin, Ethan J.; Chen, Shuo; Shao-Horn, Yang

363

Improved thermal stability of Ni-silicides on Si: C epitaxial layers  

Science Conference Proceedings (OSTI)

The thermal stability of Ni-silicides on tensily strained in situ P doped Si:C epitaxial layers was evaluated. The baseline Ni silicidation process was shown to be compatible with Si:C Recessed Source-Drain (RSD) stressors for NMOS strain engineering ... Keywords: Epitaxy, Ni, SiC stressors, Silicide, Thermal stability

V. Machkaoutsan; S. Mertens; M. Bauer; A. Lauwers; K. Verheyden; K. Vanormelingen; P. Verheyen; R. Loo; M. Caymax; S. Jakschik; D. Theodore; P. Absil; S. G. Thomas; E. H. A. Granneman

2007-11-01T23:59:59.000Z

364

First principles study of Li diffusion in I-Li_{2}NiO_{2} structure  

E-Print Network (OSTI)

First principles computations have been used to study Li mobility in the orthorhombic Li2NiO2 structure with the Immm space group (I-Li2NiO2). Understanding Li mobility in I-Li2NiO2 structure other than the conventional ...

Ceder, Gerbrand

365

Preparation and Hydrogen storage properties of Mg-rich Mg-Ni ultrafine particles  

Science Conference Proceedings (OSTI)

In the present work, Mg-rich Mg-Ni ultrafine powders were prepared through an arc plasma method. The phase components, microstructure, and hydrogen storage properties of the powders were carefully investigated. It is found that Mg2Ni and MgNi2 ...

Jianxin Zou, Haiquan Sun, Xiaoqin Zeng, Gang Ji, Wenjiang Ding

2012-01-01T23:59:59.000Z

366

Stress evolution during Ni-Si compound formation for fully silicided (FUSI) gates  

Science Conference Proceedings (OSTI)

The stress (force) evolution during the formation of different Ni silicide phases was monitored by in situ curvature measurements, for the reaction of thin Ni films of various thicknesses with 100nm polycrystalline-Si deposited on oxidized (100) Si substrates. ... Keywords: In situ XRD, In situ curvature measurements, Ni-silicides

C. Torregiani; C. Van Bockstael; C. Detavernier; C. Lavoie; A. Lauwers; K. Maex; J. A. Kittl

2007-11-01T23:59:59.000Z

367

Microstructure and Corrosion Resistance of Pulse Electroplated Ni/nano-Al2O3 Composite Coatings  

Science Conference Proceedings (OSTI)

The Ni/nano-Al2O3 composite coatings were prepared by pulse electro-plating. The experiments of corrosion resistance were carried for 304 stainless steel, pure Ni coating and Ni/nano-Al2O3 composite coating in 3.5% NaCl and 10% HCl solutions. The microstrcuture ... Keywords: pulse electro-plating, composite coating, microhardness, corrosion resistance

Hu Bin-Liang, Tan Yuan-Qiang

2012-07-01T23:59:59.000Z

368

Matching method and exact solvability of discrete PT-symmetric square wells  

E-Print Network (OSTI)

Discrete PT-symmetric square wells are studied. Their wave functions are found proportional to classical Tshebyshev polynomials of complex argument. The compact secular equations for energies are derived giving the real spectra in certain intervals of non-Hermiticity strengths Z. It is amusing to notice that although the known square well re-emerges in the usual continuum limit, a twice as rich, upside-down symmetric spectrum is exhibited by all its present discretized predecessors.

Miloslav Znojil

2006-05-24T23:59:59.000Z

369

Effect of Nafion dispersion on the stability of Pt/WO{sub 3} electrodes  

Science Conference Proceedings (OSTI)

Coelectrodeposited Pt/WO{sub 3} electrodes have very high activity for the oxidation of methanol and formic acid. However, WO{sub 3} has a slight solubility at 60 C in sulfuric acid media and this significantly reduces its activity and stability. By covering such an electrode with a thin layer of Nafion dispersion, the solubility of WO{sub 3} is reduced significantly, electrode performance is stable, and electrode activity is not affected.

Chen, K.Y.; Tseung, A.C.C. [Univ. of Essex, Colchester (United Kingdom)

1996-09-01T23:59:59.000Z

370

Stress-induced martensitic transformations in NiTi and NiTi-TiC composites investigated by neutron diffraction  

SciTech Connect

Superelastic NiTi (51.0 at% Ni) with 0, 10 and 20 vol% TiC particles were deformed under uniaxial compression as neutron diffraction spectra were simultaneously obtained. The experiments yielded in-situ measurements of the thermoelastic stress-induced transformation. A detailed Rietveld determination is made of the phase fractions and the evolving strains in the reinforcing TiC particles and the austenite as it transforms to martensite on loading (and its subsequent back transformation on unloading). These strains are used to shed light on the phenomenon of load transfer in composites where the matrix undergoes a stress-induced phase transformation.

Vaidyanathan, R. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Materials Science and Engineering; Bourke, M.A.M. [Los Alamos National Lab., NM (United States); Dunand, D.C. [Northwestern Univ., Evanston, IL (United States)

1998-12-31T23:59:59.000Z

371

INVESTIGATION OF NOVEL ALLOY TiC-Ni-Ni3Al FOR SOLID OXIDE FUEL CELL INTERCONNECT APPLICATIONS  

DOE Green Energy (OSTI)

Solid oxide fuel cell interconnect materials must meet stringent requirements. Such interconnects must operate at temperatures approaching 800 C while resisting oxidation and reduction, which can occur from the anode and cathode materials and the operating environment. They also must retain their electrical conductivity under these conditions and possess compatible coefficients of thermal expansion as the anode and cathode. Results are presented in this report for fuel cell interconnect candidate materials currently under investigation based upon nano-size titanium carbide (TiC) powders. The TiC is liquid phase sintered with either nickel (Ni) or nickel-aluminide (Ni{sub 3}Al) in varying concentrations. The oxidation resistance of the submicron grain TiC-metal materials is presented as a function weight change versus time at 700 C and 800 C for varying content of metal/intermetallic in the system. Electrical conductivity at 800 C as a function of time is also presented for TiC-Ni to demonstrate the vitality of these materials for interconnect applications. TGA studies showed that the weight gain was 0.8 mg/cm{sup 2} for TiC(30)-Ni(30wt.%) after 100 hours in wet air at 800 C and the weight gain was calculated to be 0.5205 mg/cm{sup 2} for TiC(30)- Ni(10 wt.%) after 100 hours at 700 C and 100 hours at 800 C. At room temperature the electrical conductivity was measured to be 2444 1/[ohm.cm] for TiC-Ni compositions. The electrical conductivities at 800 C in air was recorded to be 19 1/[ohm.cm] after 125 hours. Two identical samples were supplied to PNNL (Dr. Jeff Stevenson) for ASR testing during the pre-decision period and currently they are being tested there. Fabrication, oxidation resistance and electrical conductivity studies indicate that TiC-Ni-Ni{sub 3}Al ternary appears to be a very important system for the development of interconnect composition for solid oxide fuel cells.

Rasit Koc; Geoffrey Swift; Hua Xie

2005-01-25T23:59:59.000Z

372

Aqueous Phase Glycerol Reforming by PtMo Bimetallic Nano-Particle Catalyst: Product Selectivity and Structural Characterization  

Science Conference Proceedings (OSTI)

A carbon supported PtMo aqueous phase reforming catalyst for producing hydrogen from glycerol was characterized by analysis of the reaction products and pathway, TEM, XPS and XAS spectroscopy. Operando X-ray absorption spectroscopy (XAS) indicates the catalyst consists of bimetallic nano-particles with a Pt rich core and a Mo rich surface. XAS of adsorbed CO indicates that approximately 25% of the surface atoms are Pt. X-ray photoelectron spectroscopy indicates that there is unreduced and partially reduced Mo oxide (MoO{sub 3} and MoO{sub 2}), and Pt-rich PtMo bimetallic nano-particles. The average size measured by transmission electron microscopy of the fresh PtMo nano-particles is about 2 nm, which increases in size to 5 nm after 30 days of glycerol reforming at 31 bar and 503 K. The catalyst structure differs from the most energetically stable structure predicted by density functional theory (DFT) calculations for metallic Pt and Mo atoms. However, DFT indicates that for nano-particles composed of metallic Pt and Mo oxide, the Mo oxide is at the particle surface. Subsequent reduction would lead to the experimentally observed structure. The aqueous phase reforming reaction products and intermediates are consistent with both C-C and C-OH bond cleavage to generate H{sub 2}/CO{sub 2} or the side product CH{sub 4}. While the H{sub 2} selectivity at low conversion is about 75%, cleavage of C-OH bonds leads to liquid products with saturated carbon atoms. At high conversions (to gas), these will produced additional CH{sub 4} reducing the H{sub 2} yield and selectivity.

Stach E. A.; Dietrich, P.J.; Lobo-Lapidus, R.J.; Wu, T.; Sumer, A.; Akatay, M.C.; Fingland, B.R.; Guo, N.; Dumesic, J.A.; Marshall, C.L.; Jellinek, J.; Delgass, W.N.; Ribeiro, F.H.; Miller, J.T.

2012-03-01T23:59:59.000Z

373

X-ray photoelectron spectroscopy studies on Pd doped SnO{sub 2} liquid petroleum gas sensor  

Science Conference Proceedings (OSTI)

The present investigation deals with the electrical response of palladium doped tin oxide, as a means of improving the selectivity for liquid petroleum gas (LPG) in the presence of CO, CH{sub 4}. The sensor element with the composition of Pd(1.5 wt{percent}) in the base material SnO{sub 2} sintered at 800{degree}C, has shown a high sensitivity towards LPG with a negligible cross interference of CO and CH{sub 4} at an operating temperature of 350{degree}C. This greatly suggests the possibility of utilizing the sensor for the detection of LPG. X-ray photoelectron spectroscopy studies have been carried out to determine the possible chemical species involved in the gas-solid interaction and the enhancing mechanism of the Pd doped SnO{sub 2} sensor element, towards LPG sensitivity. {copyright} {ital 1997 American Institute of Physics.}

Phani, A.R. [Department of Physics, University of LAquila, 67040, LAquila (Italy)

1997-10-01T23:59:59.000Z

374

Proposed License Amendments "Revised Pressure/Temperature (P/T) Curves, and  

E-Print Network (OSTI)

(FPL) requests that Appendix A of Facility Operating Licenses DPR-31 and DPR-41 for Turkey Point Units 3 and 4 be amended to extend the heatup, cooldown, and inservice test limitations for the Reactor Coolant System (RCS). The present pressure/temperature (P/T) limits specified in Technical Specification (TS) 3/4.4.9, and in TS Figures 3.4-2, 3.4-3 and 3.4-4 apply for operation up to 19 Effective Full Power Years (EFPY). The proposed amendments will extend the service period for the new P/T limits to a maximum of 32 EFPY. The proposed amendments also revise TS 3.4.9.3, Cold Overpressure Mitigation System (COMS) setpoints. COMS is the Westinghouse version of Low Temperature Overpressure Protection (LTOP). The maximum permissible Power Operated Relief Valve (PORV) setpoint for low temperature operation of the RCS is being changed from 415 + 15 psig to < 561 psig, which includes instrument uncertainty of 70 psig, as a result of the P/T limit changes. The enable temperature for the

In Accordance Cfr; Florida Power; Light Company

2000-01-01T23:59:59.000Z

375

Microstructure and ordering parameter studies in multilayer [FePt(x)/Os]{sub n} films  

SciTech Connect

The microstructure, ordering parameter, and magnetic properties of multilayer [FePt(x)/Os]{sub n} films on glass substrate by dc-magnetron sputtering (with x being thickness in nm; Os with a fixed thickness 5 nm; n being the number of layers) have been studied as a function of the annealing temperatures between 300 and 900 deg. C. The grain size of multilayer films can be controlled by annealing temperature and thickness of the FePt layer with Os space layer. The coercivity as a function of the annealing temperature for samples with n = 1 and pure FePt behaves roughly saturated after annealing above 700 deg. C. However, for samples with n > 4 the value of H{sub c} seems still increasing with increasing annealing temperature between 600 and 900 deg. C, and the ordering parameter decreases with increasing the number of Os layers. Our experimental results are reasonably well to describe the effect of strain-assisted transformation.

Chiang, D. P. [Division of Natural Science, Ming Hsin University of Sci. and Techn., Hsinchu 304, Taiwan (China); Department of Materials Engineering, Tatung University, Taipei 104, Taiwan (China); Chen, S. Y.; Chen, Y. Y. [Institute of Physics, Academia Sinica, Taipei 115, Taiwan (China); Yao, Y. D. [Institute of Applied Science and Engineering, Fu Jen University, Taipei 242, Taiwan (China); Ouyang, H. [Department of Materials Sci. and Engn., Tsing Hua University, Hsinchu 300, Taiwan (China); Yu, C. C. [Department of Applied Physics, National University of Kaohsiung, Kaohsiung 811, Taiwan (China); Lin, H. M. [Department of Materials Engineering, Tatung University, Taipei 104, Taiwan (China)

2011-04-01T23:59:59.000Z

376

Tritium generation and neutron measurements in Pd-Si under high deuterium gas pressure  

SciTech Connect

This paper summarizes some of the methods applicable for low level tritium detection needed in the search for anomalous fusion in metal hydrides. It is also intended to further detail our tritium and neutron results that have been obtained with the Pd-Si-D system, originally presented at earlier workshops. A measure of reproducibility that was not evident in our previous work has been achieved partially due to the better detection sensitivity afforded by the use of low tritium deuterium and partially from the fact that the foil-wafer cells can be made with nearly identical electrical characteristics. This reproducibility has allowed us to narrow the optimum conditions for the experiment. While this experiment is rather different from the standard'' electrolytic cell or the Ti gas hydride experiment, similarities exist in that non equilibrium conditions are sought and the tritium generation levels are low and neutron emission is extremely weak. In contrast to many electrochemical cell experiments, the system used in these experiments is completely sealed during operation and uses no electrolyte. The major improvements to the experiment have been the use of vary low tritium deuterium for the hydriding and the replacement of the aluminum neutron counter tubes with ones of stainless steel. These changes have resulted in pronounced improvements to the detection systems since the background tritium level in the gas has been reduced by a factor of 300 and the neutron background has been decreased by a factor of 14. 16 refs., 8 figs., 1 tab.

Claytor, T.N.; Tuggle, D.G.; Menlove, H.O.

1991-01-01T23:59:59.000Z

377

Improved $^{192,194,195,196}$Pt($n,?$) and $^{192}$Ir($n,?$) astrophysical reactions rates  

E-Print Network (OSTI)

$^{192}$Pt is produced solely by the slow neutron capture (\\textit{s}) nucleosynthesis process and hence an accurate ($n$,$\\gamma $) reaction rate for this nuclide would allow its use as an important calibration point near the termination of the \\textit{s}-process nucleosynthesis flow. For this reason, we have measured neutron capture and total cross sections for $% ^{192,194,195,196,nat}$Pt in the energy range from 10 eV to several hundred keV at the Oak Ridge Electron Linear Accelerator. Measurements on the other Pt isotopes were, in part, necessitated by the fact that only a relatively small $^{192}$Pt sample of modest enrichment was available. Astrophysical $% ^{192,194,195,196}$Pt($n,\\gamma $) reaction rates, accurate to approximately 3%--5 %, were calculated from these data. No accurate reaction rates have been published previously for any of these isotopes. At \\textit{s}-process temperatures, previously recommended rates are larger (by as much as 35%) and have significantly different shapes as functions of temperature, than our new rates. We used our new Pt results, together with $^{191,193}$Ir(n,$% \\gamma $) data, to calibrate nuclear statistical model calculations and hence obtain an improved rate for the unmeasured \\textit{s}-process branching-point isotope $^{192}$Ir.

P. E. Koehler; K. H. Guber

2013-09-03T23:59:59.000Z

378

High Permeability Ternary Palladium Alloy Membranes with Improved Sulfur and Halide Tolerances  

DOE Green Energy (OSTI)

The project team consisting of Southwest Research Institute{reg_sign} (SwRI{reg_sign}), Georgia Institute of Technology (GT), the Colorado School of Mines (CSM), TDA Research, and IdaTech LLC was focused on developing a robust, poison-tolerant, hydrogen selective free standing membrane to produce clean hydrogen. The project completed on schedule and on budget with SwRI, GT, CSM, TDA and IdaTech all operating independently and concurrently. GT has developed a robust platform for performing extensive DFT calculations for H in bulk palladium (Pd), binary alloys, and ternary alloys of Pd. Binary alloys investigated included Pd96M4 where M = Li, Na, Mg, Al, Si, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Y, Zr, Nb, Mo, Tc, Ru, Rh, Ag, Cd, In, Sn, Sb, Te, Hf, Ta, W, Re, Os, Ir, Pt, Au, Tl, Pb, Bi, Ce, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu. They have also performed a series of calculations on Pd{sub 70}Cu{sub 26}Ag{sub 4}, Pd{sub 70}Cu{sub 26}Au{sub 4}, Pd{sub 70}Cu{sub 26}Ni{sub 4}, Pd{sub 70}Cu{sub 26}Pt{sub 4}, and Pd{sub 70}Cu{sub 26}Y{sub 4}. SwRI deposited and released over 160 foils of binary and ternary Pd alloys. There was considerable work on characterizing and improving the durability of the deposited foils using new alloy compositions, post annealing and ion bombardment. The 10 and 25 {micro}m thick films were sent to CSM, TDA and IdaTech for characterization and permeation testing. CSM conducted over 60 pure gas permeation tests with SwRI binary and ternary alloy membranes. To date the PdAu and PdAuPt membranes have exhibited the best performance at temperatures in the range of 423-773 C and their performance correlates well with the predictions from GT. TDA completed testing under the Department of Energy (DOE) WGS conditions on over 16 membranes. Of particular interest are the PdAuPt alloys that exhibited only a 20% drop in flux when sulfur was added to the gas mixture and the flux was completely recovered when the sulfur flow was stopped. IdaTech tested binary and ternary membranes on a simulated flue gas stream and experienced significant difficulty in mounting and testing the sputter deposited membranes. IdaTech was able to successfully test PdAu and PdAuPt membranes and saw similar sulfur tolerance to what TDA found. The Program met all the deliverables on schedule and on budget. Over ten presentations at national and international conferences were made, four papers were published (two in progress) in technical journals, and three students (2 at GT and 1 at CSM) completed their doctorates using results generated during the course of the program. The three major findings of program were; (1) the DFT modeling was verified as a predictive tool for the permeability of Pd based ternary alloys, (2) while magnetron sputtering is useful in precisely fabricating binary and ternary alloys, the mechanical durability of membranes fabricated using this technique are inferior compared to cold rolled membranes and this preparation method is currently not ready for industrial environments, (3) based on both modeling and experimental verification in pure gas and mixed gas environments PdAu and PdAuPt alloys were found to have the combination of the highest permeability and tolerance to sulfur.

K. Coulter

2010-12-31T23:59:59.000Z

379

Mechanical, Electrical, and Magnetic Properties of Ni Nanocontacts  

Science Conference Proceedings (OSTI)

The dynamic deformation upon stretching of Ni nanowires as those formed with mechanically controllable break junctions or with a scanning tunneling microscope is studied both experimentally and theoretically. Molecular dynamics simulations of the breaking ... Keywords: Ab initio, ab initio, conductance, nanocontacts, spintronics

M. R. Calvo; M. J. Caturla; D. Jacob; C. Untiedt; J. J. Palacios

2008-03-01T23:59:59.000Z

380

Molecular Dynamics Simulation of Reactions Forming Ni-Al ...  

Science Conference Proceedings (OSTI)

Abstract Scope, Alloying reactions of a Ni-coated Al nanoparticle, Al-coated ... Atomistic Modeling of Screw Dislocation Mobility in Alpha-Fe ... Mesoscale Polycrystal Calculations of Damage Histories in Shock Loaded Metals ... Multi- time Scale Modeling of the Annealing of Radiation-Induced Defects at Tilt Grain Boundaries.

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381

Electron Phonon Superconductivity in LaNiPO  

Science Conference Proceedings (OSTI)

We report first principles calculations of the electronic structure, phonon dispersions and electron phonon coupling of LaNiPO. These calculations show that this material can be explained as a conventional electron phonon superconductor in contrast to theFeAs based high temperature superconductors.

Subedi, Alaska P [ORNL; Singh, David J [ORNL; Du, Mao-Hua [ORNL

2008-01-01T23:59:59.000Z

382

In situ oxidation of ultrathin silver films on Ni(111)  

Science Conference Proceedings (OSTI)

Oxidation of silver films of one- and two-monolayer thicknesses on the Ni(111) surface was investigated by low-energy electron microscopy at temperatures of 500 and 600 K. Additionally, intensity--voltage curves were measured in situ during oxidation ...

A. Meyer; J. I. Flege; S. D. Senanayake; B. Kaemena; R. E. Rettew; F. M. Alamgir; J. Falta

2011-07-01T23:59:59.000Z

383

U.S. Department of Energy Hydrogen and Fuel Cells Program 2013...  

NLE Websites -- All DOE Office Websites (Extended Search)

Roadmap (http:www1.eere.energy.govvehiclesandfuelspdfsprogramfcttroadmapjune2013.pdf) to substantiate durability of the Pd-containing catalysts, especially the PtPdW...

384

B(E2) value of even-even 108-112Pd isotopes by interacting boson model-1*  

E-Print Network (OSTI)

This work studies the systematic reduced transition probabilities B(E2), intrinsic quadrupole moments and deformation parameters of Pd isotopes with even neutrons from N= 62 to 66. The downward reduced transition probabilities B(E2) from gamma transition 8+ to 6+, 6+ to 4+, 4+ to 2+ and 2+ to 0+ states of even-even 108-112Pd isotopes were calculated by the Interacting Boson Model (IBM-1) and compared with the available previous experimental results. The ratio of the excitation energies of the first 4+ and the first 2+ excited states, R4/2, is also studied for the classification of symmetry of these nuclei. Furthermore we have studied systematically the transition rate R of some of the low-lying quadrupole collective states in comparison with the available experimental data. The associated quadrupole moments and deformation parameters have been calculated. The results of this calculation are in good agreement with the corresponding available experimental data. The 108-112Pd isotopes show the O(6) symmetry.

I. Hossain; H. Y. Abdullah; I. M. Ahmad; M. A. Saeed

2013-10-10T23:59:59.000Z

385

Y73-004PD, B&W Y-12 10 CFR Part 851 Worker Safety and Health Program  

NLE Websites -- All DOE Office Websites (Extended Search)

Y73-004PD Rev. Date: 05/10/2011 Supersedes: 4/27/2009 Page 2 of 59 Y73-004PD Rev. Date: 05/10/2011 Supersedes: 4/27/2009 Page 2 of 59 Subject: B&W Y-12 10 CFR Part 851 Worker Safety and Health Program REVISION LOG Revision Date Description of Change Pages Affected 5/10/2011 DMR number: 11-Y12-144 Changed Wackenhut Services to WSI-Oak Ridge Added "All Other Off-site Facilities" to facility list Updated procedure titles and numbers that have been revised since April, 2009. Corrected typographical errors 5,7 7 All All 4/27/2009 DMR number: 09-Y12-259 Updated the change in company name and corrected typographical errors All 5/16/2007 New procedure DMR number: 06-ESH-21 All Y73-004PD Rev. Date: 05/10/2011 Supersedes: 4/27/2009 Page 3 of 59 Subject: B&W Y-12 10 CFR Part 851 Worker Safety and Health Program

386

Continuous spin reorientation transition in epitaxially grown antiferromagnetic NiO thin films  

SciTech Connect

Fe/NiO/MgO/Ag(001) films were grown epitaxially, and the Fe and NiO spin orientations were determined using x-ray magnetic dichroism. We find that the NiO spins are aligned perpendicularly to the in-plane Fe spins. Analyzing both the in-plane and out-of-plane spin components of the NiO layer, we demonstrate unambiguously that the antiferromagnetic NiO spins undergo a continuous spin reorientation transition from the in-plane to out-of-plane directions with increasing of the MgO thickness.

Li, J.; Arenholz, E.; Meng, Y.; Tan, A.; Park, J.; Jin, E.; Son, H.; Wu, J.; Jenkins, C. A.; Scholl, A.; Hwang, Chanyong; Qiu, Z. Q.

2011-03-01T23:59:59.000Z

387

Effect of Aging Heat Treatments on Ni52Ti48 Shape Memory Alloy  

E-Print Network (OSTI)

Ni-rich NiTi shape memory alloys (SMAs) are capable of attaining a wide range of transformation temperatures depending on the heat treatment conditions and superior thermo-mechanical cycling stability, which are desired for repeated solid-state actuation. High Ni-content Ni-rich SMAs have very low transformation temperatures in a solutionized condition due to the high Ni-content of the matrix. Slow cooling (furnacecooling) from solutionizing temperature and additional aging heat treatments result in the formation of Ni-rich precipitates such as Ni4Ti3, Ni3Ti2 and Ni3Ti and increase transformation temperatures above ambient by depleting excess Ni from the matrix. However, the precipitates do not undergo a martensitic phase transformation and they decrease the transformation strain by reducing the volume fraction of the material capable of transforming. Meanwhile, recent preliminary work shows that Ni3Ti precipitates dominate fatigue failure. The objectives of the present study are: (1) to eliminate Ni3Ti but still have Ni4Ti3 precipitates, which are responsible for the dimensional stability and increase transformation temperatures, (2) to investigate the effect of heat treatments on the transformation strain, and (3) to select single variant Ni4Ti3 precipitates through constrained aging for the formation of oriented internal stress and eventually obtain twoway shame memory effect (TWSME) and enhanced dimensional stability. Based on these objectives, the effect of aging heat treatment on transformation temperatures, microstructural evolution, and shape memory behavior were investigated for a Ni52Ti48 shape memory alloy (SMA) by using differential scanning calorimetry (DSC), optical microscopy, scanning electron microscopy (SEM), and thermo-mechanical testing, including isobaric heating-cooling experiments under various stress levels. It was observed that solutionizing at 900 degree C for 24 hours eliminated Ni3Ti type precipitates, but additional aging heat treatments are needed to form Ni4Ti3 precipitates to increase transformation temperatures. Furnace-cooling and additional aging heat treatment results in the multi-stage martensitic transformation due to chemical and stress inhomogeneities in the microstructure. Aging of the controlled furnace-cooled material at 400 degree C for 48 hours resulted in the highest transformation temperatures among all processing conditions investigated due to the combination of Ni3Ti precipitates and 27 percent volume fraction of the Ni4Ti3 precipitates, which led to the depletion of Ni from the transforming matrix. However, since overaging results in losing coherency of the precipitates, dimensional stability during isobaric thermal cycling was negatively impacted.

Akin, Erhan

2010-08-01T23:59:59.000Z

388

One-pot, high-yield synthesis of titanate nanotube bundles decorated by Pd (Au) clusters for stable electrooxidation of methanol  

Science Conference Proceedings (OSTI)

Titanate nanotube bundles assembled by several simple nanotubes were synthesized through a simple reaction between TiO{sub 2} crystallites and highly concentrated NaOH in the presence of Au or Pd sols. Due to the unique scrolling growth mechanism of titanate nanotubes (TNTs), Au or Pd clusters were encapsulated in situ by TNTs, and titanate/Au and titanate/Pd nanotube bundles were formed. In comparison with carbon nanotubes (CNTs) or active carbon that was widely used as carriers to support metal clusters, TNTs bundles can immobilize the metal clusters tightly and overcome the shortcoming of exfoliation of metal clusters from the carriers. The as-prepared titanate/metal hybrids possess mesoporosity and high surface area. The electrochemical oxidation of methanol demonstrates that titanate/Pd hybrids exhibit high electrocatalytic activity and excellent stability, and hence they should be ideal catalyst candidates in direct methanol fuel cells (DMFCs). - Graphical abstract: Titanate/Au and titanate/Pd nanotube bundles have been fabricated by taking advantage of the unique scrolling growth mechanism of titanate tubes. The titanate/Pd hybrids show stable catalytic effects toward the electrooxidation of methanol.

Xue Xiudong [Key Lab of Organic Synthesis of Jiangsu Province and Department of Chemistry, Soochow University, Suzhou, Jiangsu 215123 (China); Gu Li [College of Biology and Chemical Engineering, Jiaxing University, Jiaxing, Zhejiang 314001 (China); Cao Xuebo, E-mail: xbcao@suda.edu.c [Key Lab of Organic Synthesis of Jiangsu Province and Department of Chemistry, Soochow University, Suzhou, Jiangsu 215123 (China); Song Yingying; Zhu Lianwen; Chen Peng [Key Lab of Organic Synthesis of Jiangsu Province and Department of Chemistry, Soochow University, Suzhou, Jiangsu 215123 (China)

2009-10-15T23:59:59.000Z

389

Generic microelectronic smart sensor platform for detection of toxic, hazardous, and flammable gases  

DOE Green Energy (OSTI)

Extensive work has been performed in the past which demonstrates that various metal alloys can be used to detect different toxic, hazardous, and flammable gases. Work has been performed using Pd, Pt, Ir, PdNi, PdAg and Pt/Pd for detecting things such as Hydrogen, Hydrazine, Hydrogen Sulfide, Deuterium, Tritium, Ethanol and Hexane. Perhaps the most familiar is the use of Pd and PdNi for the detection of Hydrogen. These devices work by examining the effect of the gases on the material properties of the metal alloys. Two of the most common material properties examined in these sensors are the resistance of thin film resistors, and the flatband or threshold voltage shifts of MOS structures fabricated with a particular alloy as the gate material. While research into these sensing techniques has shown much promise, few manufacturable, fieldable devices have resulted. These sensing techniques are prone to drift problems due to temperature variations, and typically have large sample to sample variations in performance due to process control issues. Typically, these sensors require significant external instrumentation for measurement and control, making the systems large and expensive. Sandia National Laboratories has designed, fabricated and demonstrated complete functionality of a generic microelectronic based smart sensor platform intended to effectively exploit the research mentioned above into high performance, manufacturable, fieldable devices. This smart sensor platform technology fabricates 2 {mu}m CMOS digital and analog control electronics, sensing elements, and temperature control elements on the same silicon integrated circuit. Our initial demonstration of this technology incorporates PdNi as the sensing alloy for the detection of hydrogen.

Rodriguez, J.; Corbett, W.; Montague, S.; Knoll, M.; McWhorter, P.

1993-07-01T23:59:59.000Z

390

First-principles investigations of Ni3Al(111) and NiAl(110) surfaces at metal dusting conditions  

SciTech Connect

We investigate the structure and surface composition of the {gamma}{prime}-Ni{sub 3}Al(111) and {beta}-NiAl(110) alloy surfaces at conditions relevant for metal dusting corrosion related to catalytic steam reforming of natural gas. In regular service as protective coatings, nickel-aluminum alloys are protected by an oxide scale, but in case of oxide scale spallation, the alloy surface may be directly exposed to the reactive gas environment and vulnerable to metal dusting. By means of density functional theory and thermochemical calculations for both the Ni{sub 3}Al and NiAl surfaces, the conditions under which CO and OH adsorption is to be expected and under which it is inhibited, are mapped out. Because CO and OH are regarded as precursors for nucleating graphite or oxide on the surfaces, phase diagrams for the surfaces provide a simple description of their stability. Specifically, this study shows how the CO and OH coverages depend on the steam to carbon ratio (S/C) in the gas and thereby provide a ranking of the carbon limits on the different surface phases.

Saadi, Souheil

2011-03-01T23:59:59.000Z

391

Calculation of thermodynamic, electronic, and optical properties of monoclinic Mg2NiH4  

DOE Green Energy (OSTI)

Ab initio total-energy density functional theory is used to investigate the low temperature (LT) monoclinic form of Mg2NiH4. The calculated minimum energy geometry of LT Mg2NiH4 is close to that determined from neutron diffraction data, and the NiH4 complex is close to a regular tetrahedron. The enthalpies of the phase change to high temperature (HT) pseudo-cubic Mg2NiH4 and of hydrogen absorption by Mg2Ni are calculated and compared with experimental values. LT Mg2NiH4 is found to be a semiconductor with an indirect band gap of 1.4 eV. The optical dielectric function of LT Mg2NiH4 differs somewhat from that of the HT phase. A calculated thin film transmittance spectrum is consistent with an experimental spectrum.

Myers, W.R.; Richardson, T.J.; Rubin, M.D.; Wang, L-W.

2001-10-01T23:59:59.000Z

392

Effect of Cr Content on Annealing Twin Formation of Cold-Rolled Ni ...  

Science Conference Proceedings (OSTI)

Design of Pre-Weakening and Evaluation of Structural Safety for Explosive ... Crystallization Temperature of Pd-Cu-Si System Using Integrated Thin Film Samples ... Mechanical Properties of 5083 Aluminium Welds after Manual and Automatic ...

393

Effect of hydrostatic pressure on the ambient pressure superconductor CePt3Si  

E-Print Network (OSTI)

We studied the evolution of superconductivity (sc) and antiferromagnetism (afm) in the heavy fermion compound CePt3Si with hydrostatic pressure. We present a pressure-temperature phase diagram established by electrical transport measurements. Pressure shifts the superconducting transition temperature, Tc, to lower temperatures. Antiferromagnetism is suppressed at a critical pressure Pc ? 0.5 GPa. Key words: CePt3Si, superconductivity, antiferromagnetism, hydrostatic pressure Superconductivity (sc) is one of the most striking effects in solid state physics. In a conventional superconductor Cooper pairing is mediated by phonons. In general, magnetism destroys superconductivity. In heavy fermion systems, however, sc exists in close proximity to magnetism, promoting the suspicion that the sc is mediated by magnetic excitations. Since the discovery of sc in the heavy fermion compound CeCu2Si2 at atmospheric pressure [1], only a few Ce-based systems were found which also exhibit sc at atmospheric pressure, like CeMIn5 (M=Co, Ir) [4]. Most superconducting pure Ce-based systems show sc only under applied pressure sufficient to suppress long range magnetic order, like CeIn3 [2] or CeRh2Si2 [3]. CeIn3 displays a typical temperature-pressure phase diagram for these compounds; antiferromagnetism (afm) is suppressed to zero temperature with pressure and sc develops right in the vicinity where afm disappears [2]. Very recently another material, namely CePt3Si, was found showing magnetic order and sc at atmospheric pressure [5]. In contrast to the systems mentioned before, the crystal

M. Nicklas A

2004-01-01T23:59:59.000Z

394

Structure Determination of Two Modulated g-Brass Structures in the Zn-Pd System through a (3+1)-Dimensional Space Description  

Science Conference Proceedings (OSTI)

The structure determination of two composite compounds in the Zn-Pd system with close relationships to the cubic g-brass structure Zn11-dPd2+d is reported. Their structures have been solved from single crystal X-ray diffraction data within a (3 + 1)-dimensional [(3 + 1)D] formalism. Zn75.7(7)Pd24.3 and Zn78.8(7)Pd21.2 crystallize with orthorhombic symmetry, super space group Xmmm(00g)0s0 X=[(1/2,1/2,0,0);(0,1/2,1/2,1/2); (1/2,0,1/2,1/2)], with the following lattice parameters, respectively: as = 12.929(3) , bs = 9.112(4) , cs = 2.5631(7) , q = 8/13 c* and Vs = 302.1(3) A3 and as = 12.909(3) , bs = 9.115(3) , cs = 2.6052(6) , q = 11/18 c* and Vs = 306.4(2) A3. Their structures may be considered as commensurate because they can be refined in the conventional 3D space groups (Cmcm and Cmce, respectively) using super cells, but they also refined within the (3 + 1)D formalism to residual factors R = 3.22% for 139 parameters and 1184 independent reflections for Zn75.7(7)Pd24.3 and R = 3.46% for 197 parameters and 1804 independent reflections for Zn78.8(7)Pd21.2. The use of the (3 + 1)D formalism improves the results of the refinement and leads to a better understanding of the complexity of the atomic arrangement through the various modulations (occupation waves and displacive waves). Our refinements emphasize a unique Pd/Zn occupation modulation at the center of the icosahedra which is correlated with the distortion of the sites.

Gourdon, Olivier [ORNL; Izaola, Zunbeltz [Hahn-Meitner Institut, Berlin, Germany; Elcoro, Luis [University of Pais Vasco; Petricek, Vaclav [Institute of Physics, Czech Republic; Miller, Gordon J. [Iowa State University

2009-01-01T23:59:59.000Z

395

Auxiliary Ligand-Dependent Assembly of Several Ni/Ni-Cd Compounds with N2O2 Donor Tetradentate Symmetrical Schiff Base Ligand  

DOE Green Energy (OSTI)

Several low-dimensional Ni/Ni-Cd complexes containing N2O2 donor tetradentate symmetrical Schiff base ligand bis(acetylacetone)ethylene-diamine (sy-H2L2), namely, [Ni(sy-L2)]2?HLa?ClO4 (2), (HLa)2?(ClO4)?(NO3) (3), [Ni(sy-L2)X]2](4,4’-bipy) (where La = 5,7-dimethyl-3,6-dihydro-2H-1,4-diazepine, X = ClO4 (4), X=NO3 (5), [Ni(sy-L2)Cd(SCN)2]n (6) and [Ni(sy-L2)?Cd(N3)2]n (7) have been synthesized from [Ni(sy-L2)]2?H2O (1). Complex 2, is three component discrete assembly generated from (HLa)+ moiety bridged with [Ni(sy-L2)] unit and ClO4- anion. A solution containing complex 2 and Cd(NO3)2 results in a mixture of 1 and 3. Further re-crystallization of 1 and 3 with various auxiliary ligands, provides coordination complexes 4 – 7 stabilized by weak hydrogen bonds in which 6 and 7 represent the first 1D heteronuclear complexes based on symmetric acacen-base Schiff base ligand.

Ge, Ying Ying; Li, Guo-Bi; Fang, Hua-Cai; Zhan, Xu Lin; Gu, Zhi-Gang; Chen, Jin Hao; Sun, Feng; Cai, Yue-Peng; Thallapally, Praveen K.

2010-09-18T23:59:59.000Z

396

Environmentally Assisted Cracking of Ni-Base Alloys [Corrosion and  

NLE Websites -- All DOE Office Websites (Extended Search)

LWRs > Environmentally Assisted LWRs > Environmentally Assisted Cracking of Ni-Base Alloys Capabilities Materials Testing Environmentally Assisted Cracking (EAC) of Reactor Materials Corrosion Performance/Metal Dusting Overview Light Water Reactors Fatigue Testing of Carbon Steels and Low-Alloy Steels Environmentally Assisted Cracking of Ni-Base Alloys Irradiation-Induced Stress Corrosion Cracking of Austenitic Stainless Steels Steam Generator Tube Integrity Program Air Oxidation Kinetics for Zr-based Alloys Fossil Energy Fusion Energy Metal Dusting Publications List Irradiated Materials Steam Generator Tube Integrity Other Facilities Work with Argonne Contact us For Employees Site Map Help Join us on Facebook Follow us on Twitter NE on Flickr Corrosion and Mechanics of Materials Light Water Reactors

397

Gamow-Teller transitions from {sup 56}Ni  

Science Conference Proceedings (OSTI)

A new technique to measure (p,n) charge-exchange reactions in inverse kinematics at intermediate energies on unstable isotopes was successfully developed and used to study the {sup 56}Ni(p,n) reaction at 110 MeV/u. Gamow-Teller transition strengths from {sup 56}Ni to {sup 56}Cu were obtained and compared with shell-model predictions in the pf-shell using the KB3G and GXPF1A interactions. The calculations with the GXPF1A interaction reproduce the experimental GT strength distribution much better than the calculations that employed the KB3G interaction, indicating deficiencies in the spin-orbit and proton-neutron residual potentials for the latter. The results are important for improving the description of electron-capture rates on nuclei in the iron region, which are important for modeling the late evolution of core-collapse and thermonuclear supernovae.

Sasano, M. [RIKEN Nishina Center, Wako, 351-0198 (Japan); Perdikakis, G. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824-1321 (United States) and Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, MI 48824 (United States); Zegers, R.G.T. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824-1321 (United States) and Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); and others

2012-11-12T23:59:59.000Z

398

Novel electrolyte chemistries for Mg-Ni rechargeable batteries.  

DOE Green Energy (OSTI)

Commercial hybrid electric vehicles (HEV) and battery electric vehicles (BEV) serve as means to reduce the nation's dependence on oil. Current electric vehicles use relatively heavy nickel metal hydride (Ni-MH) rechargeable batteries. Li-ion rechargeable batteries have been developed extensively as the replacement; however, the high cost and safety concerns are still issues to be resolved before large-scale production. In this study, we propose a new highly conductive solid polymer electrolyte for Mg-Ni high electrochemical capacity batteries. The traditional corrosive alkaline aqueous electrolyte (KOH) is replaced with a dry polymer with conductivity on the order of 10{sup -2} S/cm, as measured by impedance spectroscopy. Several potential novel polymer and polymer composite candidates are presented with the best-performing electrolyte results for full cell testing and cycling.

Garcia-Diaz, Brenda (Savannah River National Laboratory); Kane, Marie; Au, Ming (Savannah River National Laboratory)

2010-10-01T23:59:59.000Z

399

Fabrication Of Buried Self-Organized Stripes In The Ni/C{sub 60} Composite  

Science Conference Proceedings (OSTI)

A periodic array of striped nanoscopic domains, embedded in the epitaxially grown Ni layer, was formed after thermal annealing of the Ni/Ni+C{sub 60}/C{sub 60}/Ni thin multilayer sequence deposited on the MgO(001) monocrystal. The composite was annealed in 100 deg. C/1 hr increments in the range of 200-600 deg. C, and the structural evolution of the composite was analyzed mainly by Rutherford Backscattering and Scanning Electron Microscopy. The periodic system of the stripes was revealed after annealing at 600 deg. C. The possible mechanism of the domain formation is suggested as follows: temperatures below 500 deg. C incite diffusion (and consecutive disintegration) of the C{sub 60} molecules; temperatures above 500 deg. C induce forceful intermixing of the upper Ni/Ni+C{sub 60}/C{sub 60} layers; due to the pronounced immiscibility of the Ni and C (C{sub 60}) components the process of the phase separation is triggered. In the confined crystalline matrix of the buffer Ni layer the separation proceeds coordinately according to the Ni lattice template - the stripe domains are formed in a direction parallel to the main crystallographic orientation (001) of the Ni epilayer.

Vacik, J. [Nuclear Physics Institute (NPI) of AS CR, CZ-25068 Husinec - Rez (Czech Republic); Research Center Rez, 250 68 Husinec - Rez (Czech Republic); Lavrentiev, V.; Horak, P. [Nuclear Physics Institute (NPI) of AS CR, CZ-25068 Husinec - Rez (Czech Republic); Narumi, K. [Japan Atomic Energy Agency (JAEA), 1233 Watanuki, Takasaki, 370-1292 Gunma (Japan)

2011-06-01T23:59:59.000Z

400

Swift heavy ion irradiation of Pt nanocrystals: I. shape transformation and dissolution  

Science Conference Proceedings (OSTI)

We report on the effects of swift heavy ion irradiation of embedded Pt nanocrystals (NCs), which change from spheres to prolate spheroids to rods upon irradiation. Using a broad range of ion irradiation energies and NC mean sizes we demonstrate that the elongation and dissolution processes are energy and size dependent, attaining comparable levels of shape transformation and dissolution upon a given energy density deposited in the matrix. The NC shape transformation remains operative despite discontinuous ion tracks in the matrix and exhibits a constant threshold size for elongation. In contrast, for ion irradiations in which the ion tracks are continuous, the threshold size for elongation is clearly energy dependent.

Giulian, R.; Araujo, L.L.; Kluth, P.; Sprouster, D.J.; Schnohr, C.S.; Byrne, A.P.; Ridgway, M.C. (ANU)

2011-12-09T23:59:59.000Z

Note: This page contains sample records for the topic "ni pd pt" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

The kaon mass in 2+1+1 flavor twisted mass Wilson ChPT  

E-Print Network (OSTI)

We construct the chiral low-energy effective theory for 2+1+1 flavor lattice QCD with twisted mass Wilson fermions. In contrast to existing results we assume a heavy charm quark mass such that the D mesons are too heavy to appear as degrees of freedom in the effective theory. As an application we compute the kaon mass to 1-loop order in the LCE regime. The result contains a chiral logarithm involving the neutral pion mass which has no analogue in continuum ChPT.

Bar, Oliver

2013-01-01T23:59:59.000Z

402

The method of Hill determinants in PT-symmetric quantum mechanics  

E-Print Network (OSTI)

Hill-determinant method is described and shown applicable within the so called PT-symmetric quantum mechanics. We demonstrate that in a way paralleling its traditional Hermitian applications and proofs the method guarantees the necessary asymptotic decrease of wave functions as resulting from a fine-tuned mutual cancellation of their asymptotically growing exponential components. Technically, the rigorous proof is needed/offered that in a quasi-variational spirit the method allows us to work, in its numerical implementations, with a sequence of truncated forms of the rigorous Hill-determinant power series for the normalizable bound states.

Miloslav Znojil

2004-10-04T23:59:59.000Z

403

Persistent oscillations of x-ray speckles: Pt(001) step flow.  

Science Conference Proceedings (OSTI)

We observed well-defined oscillations of speckle intensities from Pt (001) surfaces at high temperatures, persisting for tens of minutes. We used a model of hex-reconstructed terraces to show that the coherent x-rays reflected from the terraces retain their phases relative to the illumination boundary and the observed oscillations come from surface dynamics due to 'step-flow' motion. Our results demonstrate a possibility that x-ray speckles can be applied to monitor the real-time evolution of surfaces.

Pierce, M. S.; Hennessy, D. C.; Chang, K. C.; Komanicky, V.; Strzalka, J.; Sandy, A.; Barbour, A.; You, H. (Materials Science Division); ( XSD); (Safarik Univ.)

2011-01-01T23:59:59.000Z

404

Neutron to proton ratios of quasiprojectile and midrapidity emission in the {sup 58}Ni+{sup 58}Ni reaction at 52 MeV/nucleon  

SciTech Connect

By combining data from a charged particle {sup 58}Ni+{sup 58}Ni experiment at 52 MeV/nucleon with an {sup 36}Ar+{sup 58}Ni experiment at 50 MeV/nucleon for which free neutrons have been detected, an increase in the neutron to proton ratio of the whole nuclear material at midrapidity has been experimentally observed in the reaction {sup 58}Ni+{sup 58}Ni at 52 MeV/nucleon. The neutron-to-proton ratio of the quasi-projectile emission is analyzed for the same reactions and is seen to decrease below the ratio of the initial system. Those observations suggest that an asymmetric exchange of neutrons and protons between the quasiprojectile and the midrapidity region exists.

Theriault, D.; Vallee, A.; Gingras, L.; Larochelle, Y.; Roy, R.; April, A.; Beaulieu, L.; Grenier, F.; Lemieux, F.; Moisan, J.; St-Pierre, C.; Turbide, S. [Laboratoire de Physique Nucleaire, Departement de Physique, Universite Laval, Quebec, G1K 7P4 (Canada); Samri, M. [Laboratoire de Physique Nucleaire et Applications, Universite Ibn Tofail, Kenitra (Morocco); Borderie, B.; Rivet, M. F. [Institut de Physique Nucleaire, IN2P3-CNRS, F-91406 Orsay Cedex (France); Bougault, R.; Colin, J.; Cussol, D.; Durand, D.; Lecolley, J.F. [LPC, IN2P3-CNRS, ISMRA and Universite, F-14050 Caen Cedex (France)] [and others

2005-01-01T23:59:59.000Z

405

Observation of Laser Induced Magnetization Dynamics in Co/Pd Multilayers with Coherent X-ray Scattering  

SciTech Connect

We report on time-resolved coherent x-ray scattering experiments of laser induced magnetization dynamics in Co/Pd multilayers with a high repetition rate optical pump x-ray probe setup. Starting from a multi-domain ground state, the magnetization is uniformly reduced after excitation by an intense 50 fs laser pulse. Using the normalized time correlation, we study the magnetization recovery on a picosecond timescale. The dynamic scattering intensity is separated into an elastic portion at length scales above 65 nm which retains memory of the initial domain magnetization, and a fluctuating portion at smaller length scales corresponding to domain boundary motion during recovery.

Wu, Benny

2012-04-05T23:59:59.000Z

406

Pt-Co Bimetallic Catalyst Supported on Single-Walled Carbon Nanotubes: Effect of Alloy Formation and Oxygen Containing Groups †  

E-Print Network (OSTI)

Pt monometallic and Pt-Co bimetallic catalysts have been prepared on single-walled carbon nanotubes (SWNT) with and without HNO3 treatment. The HNO3 treatment introduced oxygen containing groups (OCGs), which affect both the structure and activity of the catalyst. The introduction of OCGs does not affect the structure of Pt monometallic catalysts but increased the dispersion in the bimetallic catalysts. The aqueous phase reforming (APR) activity of the bimetallic catalysts is also affected by the OCGs, because the local concentration of the reactant around the SWNT support with OCGs is less than the case without OCGs. The two effects act on activity in opposing directions so the bimetallic catalysts on the two supports give similar APR yields, but this discovery gives us direction and a basis for the future design and improvement of SWNT supported catalysts. 1.

Xiaoming Wang; Nan Li; Lisa D. Pfefferle; Gary L. Haller

2010-01-01T23:59:59.000Z

407

Fabrication of [001]L1{sub 0}-FePtRh ferro-antiferromagnetic pattern by flat-patterning method  

Science Conference Proceedings (OSTI)

A flat-patterning method that exploits the ferromagnetic (FM) - antiferromagnetic (AF) transition in [001]-oriented L1{sub 0} FePt{sub 1-x}Rh{sub x} films was investigated. FM-AF patterns with dot diameters between 15 and 1000 nm were fabricated by locally diffusing a small percentage of FePt atoms onto the FePt{sub 1-x}Rh{sub x} film. The geometric and magnetic properties of the patterns were analyzed in detail. Only the area whose composition crossed the FM-AF threshold underwent a magnetic phase change to the FM phase. FM dots with single-domain structures were observed in the AF matrix in the range of 15-100 nm by magnetic force microscopy.

Hasegawa, T.; Tomioka, T.; Ishio, S. [Department of Materials Science and Engineering, Akita University, 1-1 Tegata Gakuen-machi, Akita (Japan); Kondo, Y.; Yamane, H. [Akita Industrial Technology Center (AIT), 4-11 Sanuki Araya, Akita (Japan)

2012-04-01T23:59:59.000Z

408

Tribological behavior of NiTi alloy against 52100 steel and WC at elevated temperatures  

SciTech Connect

The dry tribological behavior of a Ti-50.3 at.% Ni alloy at temperatures of 25 deg. C, 50 deg. C and 200 deg. C was studied. The wear tests were performed on a high temperature pin-on-disk tribometer using 52100 steel and tungsten carbide pins. The worn surfaces of the NiTi alloy were examined by scanning electron microscope. The results showed that in the wear tests involving steel pins, the wear rate of the NiTi decreased as the wear testing temperature was increased. However, for the NiTi/WC contact, a reverse trend was observed. There was also a large decrease in the coefficient of friction for the NiTi/steel contact with increasing wear testing temperature. The formation of compact tribological layers could be the main reason for the reduction of the wear rate and coefficient of friction of the NiTi/steel contact at higher wear testing temperatures.

Abedini, M. [School of Metallurgy and Materials Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Ghasemi, H.M., E-mail: hghasemi@ut.ac.ir [School of Metallurgy and Materials Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Ahmadabadi, M. Nili [School of Metallurgy and Materials Engineering, University of Tehran, Tehran (Iran, Islamic Republic of)

2010-07-15T23:59:59.000Z

409

Methanol electro-oxidation on unsupported Pt-Ru alloys at different temperatures  

Science Conference Proceedings (OSTI)

A wide compositional range of unsupported platinum-ruthenium alloy catalysts were prepared by thermal decomposition of the chlorides and chloroacids. The electrocatalysts were characterized by cyclic voltammetry, X-ray diffraction, and energy-dispersive X-ray spectroscopy. The BET surface area of the electrocatalysts increases with increasing Ru content up to {approximately}70 atomic percent (a/o) and then reaches a plateau value. Electrodes fabricated from the electrocatalysts were also evaluated as anodes for methanol electro-oxidation in sulfuric acid over a range of temperatures. Unlike the situation for pure Pt, Ru is inactive for methanol electro-oxidation at 25 C but becomes active at higher temperatures. The peak current observed during an anodic potential scan gradually shifts to more cathodic potentials with increasing temperature. When a comparison is made on the basis of electrode geometric surface area, a {approximately}50 a/o ruthenium electrocatalyst provides the highest activity for methanol electro-oxidation at both 25 and 60C. The methanol electro-oxidation rate is 0.5 orders with respect to methanol concentration (between 0.1 and 2 M) for the Pt-Ru ({approximately}50:50) electrode.

Chu, D.; Gilman, S. [Army Research Lab., Fort Monmouth, NJ (United States). Physical Sciences Directorate

1996-05-01T23:59:59.000Z

410

PT-symmetry breaking in complex nonlinear wave equations and their deformations  

E-Print Network (OSTI)

We investigate complex versions of the Korteweg-deVries equations and an Ito type nonlinear system with two coupled nonlinear fields. We systematically construct rational, trigonometric/hyperbolic, elliptic and soliton solutions for these models and focus in particular on physically feasible systems, that is those with real energies. The reality of the energy is usually attributed to different realisations of an antilinear symmetry, as for instance PT-symmetry. It is shown that the symmetry can be spontaneously broken in two alternative ways either by specific choices of the domain or by manipulating the parameters in the solutions of the model, thus leading to complex energies. Surprisingly the reality of the energies can be regained in some cases by a further breaking of the symmetry on the level of the Hamiltonian. In many examples some of the fixed points in the complex solution for the field undergo a Hopf bifurcation in the PT-symmetry breaking process. By employing several different variants of the symmetries we propose many classes of new invariant extensions of these models and study their properties. The reduction of some of these models yields complex quantum mechanical models previously studied.

Andrea Cavaglia; Andreas Fring; Bijan Bagchi

2011-03-09T23:59:59.000Z

411

PT-symmetry breaking in complex nonlinear wave equations and their deformations  

E-Print Network (OSTI)

We investigate complex versions of the Korteweg-deVries equations and an Ito type nonlinear system with two coupled nonlinear fields. We systematically construct rational, trigonometric/hyperbolic, elliptic and soliton solutions for these models and focus in particular on physically feasible systems, that is those with real energies. The reality of the energy is usually attributed to different realisations of an antilinear symmetry, as for instance PT-symmetry. It is shown that the symmetry can be spontaneously broken in two alternative ways either by specific choices of the domain or by manipulating the parameters in the solutions of the model, thus leading to complex energies. Surprisingly the reality of the energies can be regained in some cases by a further breaking of the symmetry on the level of the Hamiltonian. In many examples some of the fixed points in the complex solution for the field undergo a Hopf bifurcation in the PT-symmetry breaking process. By employing several different variants of the sym...

Cavaglia, Andrea; Bagchi, Bijan

2011-01-01T23:59:59.000Z

412

Evaluation of PEMFC System Contaminants on the Performance of Pt Catalyst via Cyclic Voltammetry: Preprint  

DOE Green Energy (OSTI)

Using electrochemical cyclic voltammetry as a quick ex-situ screening tool, the impact of the extracted solution and the individual leachable constituents from prospective BOP component materials on the performance and recoverability of the platinum catalyst were evaluated. Taking an extract from Zytel{trademark} HTN51G35HSLR (PPA) as an example, the major leachable organic components are caprolactam and 1,6 hexanediol. While these organic compounds by themselves do poison the Pt catalyst to some extent, such influence is mostly recoverable by means of potential holding and potential cycling. The extracted solution, however, shows a more drastic poisoning effect and it was not recoverable. Therefore the non-recoverable poisoning effect observed for the extracted solution is not from the two organic species studied. This demonstrates the complexity of such a contaminant study. Inorganic compounds that are known poisons like sulfur even in very low concentrations, may have a more dominant effect on the Pt catalyst and the recoverability.

Wang, H.; Macomber, C.; Dinh, H. N.

2012-07-01T23:59:59.000Z

413

Advanced Electrocatalysts for PEM Fuel Cells  

NLE Websites -- All DOE Office Websites (Extended Search)

Pt 3 Ni (111) Unique Adsorption Properties of Pt-Skin Surface: Pt 3 Ni(111) Agewandte Chemie 51(2012)3139 6 Experimental activity trends In situ characterized and computationally...

414

INTERPRTATION DES FAUTES D'EMPILEMENT DANS L'ANTIFERROMAGNTIQUE K2NiF4  

E-Print Network (OSTI)

859. INTERPR�TATION DES FAUTES D'EMPILEMENT DANS L'ANTIFERROMAGN�TIQUE K2NiF4 Par R. PLUMIER. 2014 Nous montrons qu'une légère déformation orthorhombique de la maille de K2NiF4 entraîne parNiF4 cell leads to a decrease of the free energy of the crystal through an exchange striction

Paris-Sud XI, Université de

415

High Temperature Corrosion Resistance of Fe-Ni-Cr Alloys in CO2 ...  

Science Conference Proceedings (OSTI)

Austenitic Steel Oxidation in Steam: Alloy Composition and Surface Modification ... Ni-Base Alloys for Use as Components in Advanced-USC Steam Turbines.

416

In-Situ Neutron Diffraction Study of Porous NiO-YSZ Composite ...  

Science Conference Proceedings (OSTI)

Presentation Title, In-Situ Neutron Diffraction Study of Porous NiO-YSZ Composite ... Gas Turbines of the Future: Hydrogen and Oxy-Combustion Environments.

417

Investigation on Oxidation Resistance of NiCoCrAlY Coating ...  

Science Conference Proceedings (OSTI)

Presentation Title, Investigation on Oxidation Resistance of NiCoCrAlY Coating Irradiated by High Current Pulsed Electron Beam. Author(s), Xianxiu Mei, Cunxia  ...

418

Pressure Water Leaching Molybdenum and Nickel from Mo-Ni ore of ...  

Science Conference Proceedings (OSTI)

Presentation Title, Pressure Water Leaching Molybdenum and Nickel from Mo-Ni ore of Black Shale without Reagent. Author(s), Zhigan Deng. On-Site Speaker ...

419

Further Characterization of New NiTi Wire and Rotary Endodontic ...  

Science Conference Proceedings (OSTI)

Presentation Title, Further Characterization of New NiTi Wire and Rotary ... Higher-resolution transmission electron microscopy examination of M-Wire used to ...

420

Effects of Changes in Alloy Composition on Toughness of Ni-Ta-X ...  

Science Conference Proceedings (OSTI)

On-Site Speaker (Planned), John J Lewandowski. Abstract Scope, The effects of changes in alloy chemistry on the fracture behavior of Ni-Ta-X glasses are ...

Note: This page contains sample records for the topic "ni pd pt" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

F-8: Modeling of Mn-Ni-Si-Cu Precipitation in Reactor Pressure ...  

Science Conference Proceedings (OSTI)

Presentation Title, F-8: Modeling of Mn-Ni-Si-Cu Precipitation in Reactor .... Steels 316 and Comparison with the Rate Theory Model of a Multicomponent System.

422

SF6432-NI (02-01-12) Fixed Price Former Soviet Union  

NLE Websites -- All DOE Office Websites (Extended Search)

CORPORATION SF 6432-NI (072013) SECTION II STANDARD TERMS AND CONDITIONS FOR FIXED PRICE CONTRACTS WITH THE NEWLY INDEPENDENT STATES OF THE FORMER SOVIET UNION INDEX OF...

423

Mixed Conducting Molten Salt Electrolyte for Na/NiCl 2 Cell  

Science Conference Proceedings (OSTI)

Catalytic Properties of Ni-Al Intermetallic Nanoparticle Catalysts for Hydrogen Production from Methanol and Methane · Ca, Li and Mg Based Lightweight ...

424

Thermal and irradiation-induced phase separation in Fe-Ni based ...  

Science Conference Proceedings (OSTI)

magnetic, low-expansion Invar-type alloys and model austenitic Fe-Ni based alloys studied for ...... fast reactors such as the Fast Flux Test Facility (FFTF).

425

Thermodynamic Modeling of the Mg-Cu-Ni Ternary System using ...  

Science Conference Proceedings (OSTI)

About this Abstract. Meeting, COM 2011. Symposium, LIGHT METALS. Presentation Title, Thermodynamic Modeling of the Mg-Cu-Ni Ternary System using the ...

426

Effect of Steam Exposure on the Creep Properties of Ni-Based Alloys  

Science Conference Proceedings (OSTI)

Symposium, Properties, Processing, and Performance of Steels and Ni-Based Alloys for Advanced Steam Conditions. Presentation Title, Effect of Steam ...

427

Steam Oxidation of Fe-20Cr-30Ni-2Nb Austenitic Steel at 973 K  

Science Conference Proceedings (OSTI)

Symposium, Properties, Processing, and Performance of Steels and Ni-Based Alloys for Advanced Steam Conditions. Presentation Title, Steam Oxidation of ...

428

Influence of the Water Vapour on the Oxidation Behaviour of a Ni ...  

Science Conference Proceedings (OSTI)

Presentation Title, Influence of the Water Vapour on the Oxidation Behaviour of a Ni-based Alloy – Interest of an In-situ Microscopic Approach of Phenomena.

429

Ageing and Toughness of a Mn-Ni-Mo PWR Steel  

Science Conference Proceedings (OSTI)

Abstract Scope, Mn-Ni-Mo steels are widely used in the fabrication of pressurisers, steam generators and pressure vessels of pressurised water reactors (PWR).

430

Reduction of the Ni- and Ti-oxide mixtures by natural gas  

Science Conference Proceedings (OSTI)

In this work, the reduction of Ni- and Ti-oxides by natural gas has been studied. ... Reaction mechanism and reaction rate of Sn evaporation from liquid steel.

431

D3: Weld Solidification Behavior of Ni-base Superalloys for Use in ...  

Science Conference Proceedings (OSTI)

Presentation Title, D3: Weld Solidification Behavior of Ni-base Superalloys for Use in Advanced Supercritical Coal-fired Power Plants. Author(s), David Tung, ...

432

Investigation on Corrosion Behaviour of Ni-Based Alloys in Molten ...  

Science Conference Proceedings (OSTI)

In this paper, corrosion processes of Ni-based superalloys including Inconel 600, Hastelloy X and Hastelloy C-276 were investigated in molten fluoride salts ...

433

Self-assembly of Ni-nanoparticles in Aerosols Produced Thermally ...  

Science Conference Proceedings (OSTI)

Abstract Scope, The self-assembly behavior in Ni-aerosols was studied on- ground ... In microgravity, convection within the thermally produced aerosols could be ...

434

Electron Microscopy Study of Hypo-Stoichiometric Fe-Pd Nanocomposites Resulting from Combined Reaction Thermomechanical Processing  

Science Conference Proceedings (OSTI)

Hypo stoichiometric Fe-Pd binary alloys (35-45 at% Pd) were severely deformed (>90%) and subsequently aged to induce concomitant recrystallization, precipitation, and ordering. This thermomechanical processing strategy was articulated by Hornbogen [1] over thirty years ago. The resulting exchange-coupled ferromagnets contain ferrite precipitates and a complex metastable twophase lamellar transformation product comprised of ordered L10 and a metastable FCC phase. The later duplex microconstituent is suggested to form in conjunction with a so-called pseudospinodal reaction [2] involving emerging cubic and tetragonal phases, whereby phase separation and ordering result from continuous changes in composition and a reduction in symmetry, cubic to tetragonal. The deformation texture of the parent austenite is substantially retained in the transformation product, resulting in anisotropy of the magnetic properties as determined by magnetometry (VSM). This paper presents electron microscopy results elucidating the crystallography and morphology of the phase mixtures including HREM. Magnetic field annealing is also included as a branch of our thermomechanical processing strategy, and we discuss the influence of the external fields on recrystallization, precipitation, and ordering. This work was performed in cooperation with ORNL and the NHMFL and is supported by the NSF DMR.

Cantando, Elizabeth Dawn [University of Virginia; Ludtka, Gerard Michael [ORNL; Ludtka, Gail Mackiewicz- [ORNL; Soffa, William A [University of Virginia

2011-01-01T23:59:59.000Z

435

Anisotropic short-range structure of Co{sub 0.16}Pd{sub 0.84} alloy films having perpendicular magnetic anisotropy  

SciTech Connect

Polarized CoK edge extended x-ray absorption fine structure measurements obtained with electric vector parallel and perpendicular to the film plane indicate differences in Co bonding along these two directions in room-temperature evaporated Co{sub 0.16}Pd{sub 0.84} alloy films. A local modulation of the Co fraction whose amplitudes are 0.05{endash}0.09 exists along the growth direction in the alloy films. Pd underlayer and Pd spacer layers alternated with the alloy layer induce coherency strains resulting in an anisotropic effective strain state. Both anisotropic strain and local compositional modulation are likely to contribute to the perpendicular magnetic anisotropy observed in these alloys. {copyright} {ital 1997 American Institute of Physics.}

Kim, S. [Advanced Light Source, Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720 (United States)] [Advanced Light Source, Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720 (United States); Chernov, V.A. [Siberian Synchrotron Radiation Center of Budker Institute of Nuclear Physics, Institute of Catalysis, 630090 Novosibirsk (Russia)] [Siberian Synchrotron Radiation Center of Budker Institute of Nuclear Physics, Institute of Catalysis, 630090 Novosibirsk (Russia); Kortright, J.B. [Materials Science Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720 (United States)] [Materials Science Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720 (United States); Koo, Y.M. [Department of Materials Science and Engineering, Pohang University of Science and Technology, Pohang 790-784 (Republic of Korea)] [Department of Materials Science and Engineering, Pohang University of Science and Technology, Pohang 790-784 (Republic of Korea)

1997-07-01T23:59:59.000Z

436

Direct observation of surface ethyl to ethane interconversion upon C2H4 hydrogenation over Pt/Al2O3 catalyst by time-resolved FT-IR spectroscopy  

E-Print Network (OSTI)

In-Situ Spectroscopy of Catalysts; Weckhuysen, B.M. , Ed. ;Hydrogenation over Pt/Al 2 O 3 Catalyst by Time-Resolved FT-over alumina-supported Pt catalyst were recorded at 25 ms

Wasylenko, Walter; Frei, Heinz

2004-01-01T23:59:59.000Z

437

$J/?$ production at low $p_T$ in Au+Au and Cu+Cu collisions at $\\sqrt{s_{_{NN}}}$ = 200 GeV at STAR  

E-Print Network (OSTI)

The $J/\\psi$ $p_T$ spectrum and nuclear modification factor ($R_{\\textit{AA}}$) are reported for $p_T < 5$ GeV/c and $|y|<1$ from 0-60% central Au+Au and Cu+Cu collisions at $\\sqrt{s_{_{NN}}} =200$ GeV at STAR. A significant suppression of $p_T$-integrated $J/\\psi$ production is observed in central Au+Au events, with less suppression observed in Cu+Cu. The $p_T$ dependence of the $R_{\\textit{AA}}$ is observed to increase at a higher $p_T$ region. The data are compared with the previously published RHIC results. Comparing with model calculations, it is found that the invariant yields at low $p_T$ are significantly above hydrodynamic flow predictions but are consistent with models that include color screening and regeneration.

STAR Collaboration; L. Adamczyk; J. K. Adkins; G. Agakishiev; M. M. Aggarwal; Z. Ahammed; I. Alekseev; J. Alford; C. D. Anson; A. Aparin; D. Arkhipkin; E. C. Aschenauer; G. S. Averichev; J. Balewski; A. Banerjee; Z. Barnovska; D. R. Beavis; R. Bellwied; A. Bhasin; A. K. Bhati; P. Bhattarai; H. Bichsel; J. Bielcik; J. Bielcikova; L. C. Bland; I. G. Bordyuzhin; W. Borowski; J. Bouchet; A. V. Brandin; S. G. Brovko; S. Bültmann; I. Bunzarov; T. P. Burton; J. Butterworth; H. Caines; M. Calderón de la Barca Sánchez; D. Cebra; R. Cendejas; M. C. Cervantes; P. Chaloupka; Z. Chang; S. Chattopadhyay; H. F. Chen; J. H. Chen; L. Chen; J. Cheng; M. Cherney; A. Chikanian; W. Christie; J. Chwastowski; M. J. M. Codrington; R. Corliss; J. G. Cramer; H. J. Crawford; X. Cui; S. Das; A. Davila Leyva; L. C. De Silva; R. R. Debbe; T. G. Dedovich; J. Deng; A. A. Derevschikov; R. Derradi de Souza; S. Dhamija; B. di Ruzza; L. Didenko; C. Dilks; F. Ding; P. Djawotho; X. Dong; J. L. Drachenberg; J. E. Draper; C. M. Du; L. E. Dunkelberger; J. C. Dunlop; L. G. Efimov; J. Engelage; K. S. Engle; G. Eppley; L. Eun; O. Evdokimov; R. Fatemi; S. Fazio; J. Fedorisin; P. Filip; E. Finch; Y. Fisyak; C. E. Flores; C. A. Gagliardi; D. R. Gangadharan; D. Garand; F. Geurts; A. Gibson; M. Girard; S. Gliske; D. Grosnick; Y. Guo; A. Gupta; S. Gupta; W. Guryn; B. Haag; O. Hajkova; A. Hamed; L-X. Han; R. Haque; J. W. Harris; J. P. Hays-Wehle; S. Heppelmann; A. Hirsch; G. W. Hoffmann; D. J. Hofman; S. Horvat; B. Huang; H. Z. Huang; P. Huck; T. J. Humanic; G. Igo; W. W. Jacobs; H. Jang; E. G. Judd; S. Kabana; D. Kalinkin; K. Kang; K. Kauder; H. W. Ke; D. Keane; A. Kechechyan; A. Kesich; Z. H. Khan; D. P. Kikola; I. Kisel; A. Kisiel; D. D. Koetke; T. Kollegger; J. Konzer; I. Koralt; W. Korsch; L. Kotchenda; P. Kravtsov; K. Krueger; I. Kulakov; L. Kumar; R. A. Kycia; M. A. C. Lamont; J. M. Landgraf; K. D. Landry; J. Lauret; A. Lebedev; R. Lednicky; J. H. Lee; W. Leight; M. J. LeVine; C. Li; W. Li; X. Li; X. Li; Y. Li; Z. M. Li; L. M. Lima; M. A. Lisa; F. Liu; T. Ljubicic; W. J. Llope; R. S. Longacre; X. Luo; G. L. Ma; Y. G. Ma; D. M. M. D. Madagodagettige Don; D. P. Mahapatra; R. Majka; S. Margetis; C. Markert; H. Masui; H. S. Matis; D. McDonald; T. S. McShane; N. G. Minaev; S. Mioduszewski; B. Mohanty; M. M. Mondal; D. A. Morozov; M. G. Munhoz; M. K. Mustafa; B. K. Nandi; Md. Nasim; T. K. Nayak; J. M. Nelson; L. V. Nogach; S. Y. Noh; J. Novak; S. B. Nurushev; G. Odyniec; A. Ogawa; K. Oh; A. Ohlson; V. Okorokov; E. W. Oldag; R. A. N. Oliveira; M. Pachr; B. S. Page; S. K. Pal; Y. X. Pan; Y. Pandit; Y. Panebratsev; T. Pawlak; B. Pawlik; H. Pei; C. Perkins; W. Peryt; P. Pile; M. Planinic; J. Pluta; D. Plyku; N. Poljak; J. Porter; A. M. Poskanzer; N. K. Pruthi; M. Przybycien; P. R. Pujahari; H. Qiu; A. Quintero; S. Ramachandran; R. Raniwala; S. Raniwala; R. L. Ray; C. K. Riley; H. G. Ritter; J. B. Roberts; O. V. Rogachevskiy; J. L. Romero; J. F. Ross; A. Roy; L. Ruan; J. Rusnak; N. R. Sahoo; P. K. Sahu; I. Sakrejda; S. Salur; A. Sandacz; J. Sandweiss; E. Sangaline; A. Sarkar; J. Schambach; R. P. Scharenberg; A. M. Schmah; W. B. Schmidke; N. Schmitz; J. Seger; P. Seyboth; N. Shah; E. Shahaliev; P. V. Shanmuganathan; M. Shao; B. Sharma; W. Q. Shen; S. S. Shi; Q. Y. Shou; E. P. Sichtermann; R. N. Singaraju; M. J. Skoby; D. Smirnov; N. Smirnov; D. Solanki; P. Sorensen; U. G. deSouza; H. M. Spinka; B. Srivastava; T. D. S. Stanislaus; J. R. Stevens; R. Stock; M. Strikhanov; B. Stringfellow; A. A. P. Suaide; M. Sumbera; X. Sun; X. M. Sun; Y. Sun; Z. Sun; B. Surrow; D. N. Svirida; T. J. M. Symons; A. Szanto de Toledo; J. Takahashi; A. H. Tang; Z. Tang; T. Tarnowsky; J. H. Thomas; A. R. Timmins; D. Tlusty; M. Tokarev; S. Trentalange; R. E. Tribble; P. Tribedy; B. A. Trzeciak; O. D. Tsai; J. Turnau; T. Ullrich; D. G. Underwood; G. Van Buren; G. van Nieuwenhuizen; J. A. Vanfossen, Jr.; R. Varma; G. M. S. Vasconcelos; A. N. Vasiliev; R. Vertesi; F. Videbæk; Y. P. Viyogi; S. Vokal; A. Vossen; M. Wada; M. Walker; F. Wang; G. Wang; H. Wang; J. S. Wang; X. L. Wang; Y. Wang; Y. Wang; G. Webb; J. C. Webb; G. D. Westfall; H. Wieman; S. W. Wissink; R. Witt; Y. F. Wu; Z. Xiao; W. Xie; K. Xin; H. Xu; N. Xu; Q. H. Xu; Y. Xu; Z. Xu; W. Yan; C. Yang; Y. Yang; Y. Yang; Z. Ye; P. Yepes; L. Yi; K. Yip; I-K. Yoo; Y. Zawisza; H. Zbroszczyk; W. Zha; Zhang; J. B. Zhang; S. Zhang; X. P. Zhang; Y. Zhang; Z. P. Zhang; F. Zhao; J. Zhao; C. Zhong; X. Zhu; Y. H. Zhu; Y. Zoulkarneeva; M. Zyzak

2013-10-14T23:59:59.000Z

438

Large energy absorption in Ni-Mn-Ga/polymer composites  

SciTech Connect

Ferromagnetic shape memory alloys can respond to a magnetic field or applied stress by the motion of twin boundaries and hence they show large hysteresis or energy loss. Ni-Mn-Ga particles made by spark erosion have been dispersed and oriented in a polymer matrix to form pseudo 3:1 composites which are studied under applied stress. Loss ratios have been determined from the stress-strain data. The loss ratios of the composites range from 63% to 67% compared to only about 17% for the pure, unfilled polymer samples.

Feuchtwanger, Jorge; Richard, Marc L.; Tang, Yun J.; Berkowitz, Ami E.; O'Handley, Robert C.; Allen, Samuel M. [Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); University of California, San Diego, La Joya, California 92093 (United States); Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

2005-05-15T23:59:59.000Z

439

Upper critical field of Mo-Ni heterostructures  

SciTech Connect

Upper critical field and its anisotropy have been measured on two very short wavelength Mo-Ni heterostructures of different degrees of perfection, lambda = 13.8A (disordered structure) and lambda = 16.6A (layered structure). In both cases the parallel critical field has an unexpected temperature dependence, a large and temperature dependent anisotropy, and over 60% enhancement over the Clogston-Chandrasekhar limit. Data are fit to the Werthamer-Helfand-Hohenberg theory and the spin-orbit scattering times are found to be 1.79 x 10 T s and 2 x 10 T s, respectively.

Uher, C.; Watson, W.J.; Cohn, J.L.; Schuller, I.K.

1985-12-01T23:59:59.000Z

440

Grain Refinement in TiC-Ni3Al Composites  

DOE Green Energy (OSTI)

The Cooperative Research and Development Agreement (CRADA) was to develop composites of TiC-Ni{sub 3}Al with refined grain microstructures for application in diesel engine fuel injection devices. Grain refinement is important for improved wear resistance and high strength for the applications of interest. Attrition milling effectively reduces the initial particle size and leads to a reduction of the final grain size. However, an increase in the oxygen content occurs concomitantly with the grinding operation and decreased densification of the compacts occurs during sintering.

Tiegs, T.N.

2001-01-30T23:59:59.000Z

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441

Spectromicroscopy study of interfacial Co/NiO(001)  

SciTech Connect

Photoemission electron microscopy (PEEM) with linearly polarized x-rays is used to determine the orientation of antiferromagnetic domains by monitoring the relative peak intensities at the 3d transition metal L{sub 2} absorption edge. In such an analysis the orientations of the x-ray polarization E and magnetization H with respect to the crystalline axes has to be taken into account. We address this problem by presenting a general expression of the angular dependence for both x-ray absorption spectroscopy and x-ray magnetic linear dichroism (XMLD) for arbitrary direction of E and H in the (001) cubic plane. In cubic symmetry the angular dependent XMLD is a linear combination of two spectra with different photon energy dependence, which reduces to one spectrum when E or H is along a high-symmetry axis. The angular dependent XMLD can be separated into an isotropic term, which is symmetric along H, and an anisotropic term, which depends on the orientation of the crystal axes. The anisotropic term has maximal intensity when E and H have equal but opposite angles with respect to the [100] direction. The Ni{sup 2+} L{sub 2} edge has the peculiarity that the isotropic term vanishes, which means that the maximum in the XMLD intensity is observed not only for E {parallel} H {parallel} [100] but also for (E {parallel} [110], H {parallel} [110]). We apply the angular dependent theory to determine the spin orientation near the Co/NiO(100) interface. The PEEM images show that the ferromagnetic Co moments and antiferromagnetic NiO moments are aligned perpendicular to each other. By rotating the sample with respect to the linear x-ray polarization we furthermore find that the perpendicular coupling with the ferromagnetic Co layer at the interface causes a canting of the antiferromagnetic Ni moments. This shows that taking into account the angular dependence of the XMLD in the detailed analysis of PEEM images leads to an accurate retrieval of the spin axes of the antiferromagnetic domains.

van der Laan, Gerrit; Telling, Neil; Potenza, Alberto; Dhesi, Sarnjeet; Arenholz, Elke

2010-09-26T23:59:59.000Z

442

Improved oxidation sulfidation resistance of Fe-Cr-Ni alloys  

DOE Patents (OSTI)

High temperature resistance of Fe-Cr-Ni alloy compositions to oxidative and/or sulfidative conditions is provided by the incorporation of about 1 to 8 wt % of Zr or Nb and results in a two-phase composition having an alloy matrix as the first phase and a fine grained intermetallic composition as the second phase. The presence and location of the intermetallic composition between grains of the matrix provides mechanical strength, enhanced surface scale adhesion, and resistance to corrosive attack between grains of the alloy matrix at temperatures of 500 to 1000/sup 0/C.

Natesan, K.; Baxter, D.J.

1983-07-26T23:59:59.000Z

443

10 CFR Ch. III (1-1-11 Edition) Pt. 851, App. B  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

10 CFR Ch. III (1-1-11 Edition) Pt. 851, App. B must meet the applicable electrical safety codes and standards referenced in § 851.23. 11. NANOTECHNOLOGY SAFETY-RESERVED The Department has chosen to reserve this section since policy and procedures for nano- technology safety are currently being devel- oped. Once these policies and procedures have been approved, the rule will be amended to include them through a rulemaking con- sistent with the Administrative Procedure Act. 12. WORKPLACE VIOLENCE PREVENTION- RESERVED The Department has chosen to reserve this section since the policy and procedures for workplace violence prevention are currently being developed. Once these policies and pro- cedures have been approved, the rule will be amended to include them through a rule-

444

Tsallis Fits to p_T Spectra and Multiple Hard Scattering in pp Collisions at LHC  

Science Conference Proceedings (OSTI)

Phenomenological Tsallis fits to the CMS, ATLAS, and ALICE transverse momentum spectra of hadrons for pp collisions at LHC were recently found to extend over a large range of the fitting transverse momentum. We investigate whether the few degrees of freedom in the Tsallis parametrization may arising from the relativistic parton-parton hard-scattering and related hard processes. The effects of multiple hard-scattering and parton showering on the power law are discussed. We find that although the transverse spectra of both hadrons and jets exhibit power-law behaviour of 1/pT^n at high pT, the power indices n for hadrons are categorically greater than those for jets, for which n~4.

Wong, Cheuk-Yin [ORNL; Wilk, Grzegorz [National Centre for Nuclear Research, Warsaw, Poland

2013-01-01T23:59:59.000Z

445

Improvement of Pt/C/PTFE catalyst type used for hydrogen isotope separation  

Science Conference Proceedings (OSTI)

The CANDU reactor from the Nuclear Power plant Cernavoda (Romania)) is the most powerful tritium source from Europe. This reactor is moderated and cooled by heavy water that becomes continuously contaminated with tritium. Because of this reason, the National R and amp;D Inst. for Cryogenic and Isotopic Technologies developed a detritiation technology based on catalytic isotopic exchange and cryogenic distillation. The main effort of our Inst. was focused on finding more efficient catalysts with a longer operational life. Some of the tritium removal processes involved in Fusion Science and Technology use this type of catalyst 1. Several Pt/C/PTFE hydrophobic catalysts that could be used in isotopic exchange process 2,3,4 were produced. The present paper presents a comparative study between the physical and morphological properties of different catalysts manufactured by impregnation at our institute. The comparison consists of a survey of specific surface, pores volume and pores distribution. (authors)

Vasut, F.; Preda, A.; Zamfirache, M.; Bornea, A. M.; Stefanescu, I.; Pearsica, C. [INC-DTCI, ICSI Rm. Valcea, Uzinei Street 4, Rm. Valcea (Romania)

2008-07-15T23:59:59.000Z

446

Force Field Development and Molecular Dynamics of [NiFe] Hydrogenase  

Science Conference Proceedings (OSTI)

Classical molecular force-field parameters describing the structure and motion of metal clusters in [NiFe] hydrogenase enzymes can be used to compare the dynamics and thermodynamics of [NiFe] under different oxidation, protonation, and ligation circumstances. Using density functional theory (DFT) calculations of small model clusters representative of the active site and the proximal, medial, and distal Fe/S metal centers and their attached protein side chains, we have calculated classical force-field parameters for [NiFe] in reduced and oxidized states, including internal coordinates, force constants, and atom-centered charges. Derived force constants revealed that cysteinate ligands bound to the metal ions are more flexible in the Ni-B active site, which has a bridging hydroxide ligand, than in the Ni-C active site, which has a bridging hydride. Ten nanosecond all-atom, explicit-solvent MD simulations of [NiFe] hydrogenase in oxidized and reduced catalytic states established the stability of the derived force-field parameters in terms of C{alpha} and metal cluster fluctuations. Average active site structures from the protein MD simulations are consistent with [NiFe] structures from the Protein Data Bank, suggesting that the derived force-field parameters are transferrable to other hydrogenases beyond the structure used for testing. A comparison of experimental H{sub 2}-production rates demonstrated a relationship between cysteinate side chain rotation and activity, justifying the use of a fully dynamic model of [NiFe] metal cluster motion.

Smith, Dayle MA; Xiong, Yijia; Straatsma, TP; Rosso, Kevin M.; Squier, Thomas C.

2012-05-09T23:59:59.000Z

447

A Linear Combination Analyses Approach For Directly Speciating Ni Contaminated Soils.  

E-Print Network (OSTI)

A Linear Combination Analyses Approach For Directly Speciating Ni Contaminated Soils. (S02-trivedi215458-Oral) Abstract: To provide an accurate description of the fate of Ni in aerial- contaminated soils to combine multiple analytical techniques to accurately determine metal speciation in complex soil systems

Sparks, Donald L.