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1

Transition metal-promoted oxygen ion conductors as oxidation catalyst  

SciTech Connect (OSTI)

A novel metal oxide composite catalyst for the complete oxidation of carbon monoxide and hydrocarbons was prepared by combining oxygen ion conducting materials with active transition metals. The oxygen ion conductors used were typical fluorite-type oxides, such as ceria, zirconia, and others. Active base metal catalysts, such as copper, were used as additives to promote the catalytic properties of oxygen ion conductors. The intimate contact of the two kinds of materials gave rise to a highly active oxidation catalyst. On Cu-Ce-O composite catalysts, 95% of carbon monoxide was oxidized by air at {approximately} 100 C. Complete methane oxidation on the same catalyst took place at {approximately} 550 C. When the stoichiometric amount of sulfur dioxide was sued to oxidize carbon monoxide, 96% of sulfur dioxide was reduced to elemental sulfur at temperatures above 460 C with 99% of sulfur dioxide conversion. This type of composite catalyst also showed excellent resistance to water poisoning.

Liu, W.; Sarofim, A. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Chemical Engineering; Flytzani-Stephanopoulos, M. [Tufts Univ., Medford, MA (United States). Dept. of Chemical Engineering

1994-12-31T23:59:59.000Z

2

Route to transition metal carbide nanoparticles through cyanamide and metal oxides  

SciTech Connect (OSTI)

We have designed an efficient route to the synthesis of transition metal carbide nanoparticles starting from an organic reagent cyanamide and transition metal oxides. Four technologically important metal carbide nanoparticles such as tungsten carbide, niobium carbide, tantalum carbide and vanadium carbide were synthesized successfully at moderate temperatures. It is found that cyanamide is an efficient carburization reagent and that the metal oxides are completely transmitted into the corresponding carbide nanoparticles. A possible mechanism is proposed to explain the results of the reaction between cyanamide and the metal oxides.

Li, P.G. [Department of Physics, Center for Optoelectronics Materials and Devices, Zhejiang Sci-Tech University, Xiasha College Park, Hangzhou 310018 (China)], E-mail: peigangiphy@yahoo.com.cn; Lei, M.; Tang, W.H. [Department of Physics, Center for Optoelectronics Materials and Devices, Zhejiang Sci-Tech University, Xiasha College Park, Hangzhou 310018 (China)

2008-12-01T23:59:59.000Z

3

Nonpolar resistance switching of metal/binary-transition-metal oxides/metal sandwiches: Homogeneous/inhomogeneous transition of current distribution  

Science Journals Connector (OSTI)

Exotic features of a metal/oxide/metal sandwich, which will be the basis for a drastically innovative nonvolatile memory device, is brought to light from a physical point of view. Here the insulator is one of the ubiquitous and classic binary-transition-metal oxides (TMO), such as Fe2O3, NiO, and CoO. The sandwich exhibits a resistance that reversibly switches between two states: one is a highly resistive off state and the other is a conductive on state. Several distinct features were universally observed in these binary TMO sandwiches: namely, nonpolar switching, nonvolatile threshold switching, and current-voltage duality. From the systematic sample-size dependence of the resistance in on and off states, we conclude that the resistance switching is due to the formation of “electric faucet” at the interface, which shows up as a homogeneous to inhomogeneous transition of the current distribution.

I. H. Inoue; S. Yasuda; H. Akinaga; H. Takagi

2008-01-03T23:59:59.000Z

4

Photoelectron Imaging Spectroscopic Investigations of Transition Metal Silicides and Oxides.  

E-Print Network [OSTI]

??This dissertation presents the experimental progress in the use of photoelectron imaging spectroscopy to probe the electronic structure of negatively charged transition metal silicides and… (more)

Gunaratne, K. Don

2012-01-01T23:59:59.000Z

5

TRANSITION DE MOTT METAL-INSULATOR TRANSITIONS  

E-Print Network [OSTI]

predominantly non-trivalent ions favor the metallicstate. I. Introduction. -Transition metal oxides form a class that such a transition would be dis- continuous as a function of volume [8], and he later proposed a phase diagramTRANSITION DE MOTT METAL-INSULATOR TRANSITIONS IN TRANSITION METAL OXIDES by D. B. McWHAN, A. MENTH

Paris-Sud XI, Université de

6

Transition metal oxides deposited on rhodium and platinum: Surface chemistry and catalysis  

SciTech Connect (OSTI)

The surface chemistry and catalytic reactivity of transition metal oxides deposited on Rh and Pt substrates has been examined in order to establish the role of oxide-metal interactions in influencing catalytic activity. The oxides investigated included titanium oxide (TiOx), vanadium oxide (VOx), iron oxide (FeOx), zirconium oxide (ZrOx), niobium oxide (NbOx), tantalum oxide (TaOx), and tungsten oxide (WOx). The techniques used to characterize the sample included AES, XPS, LEED, TPD, ISS, and STM. After characterization of the surface in UHV, the sample was enclosed in an atmospheric reaction cell to measure the influence of the oxide deposits on the catalytic activity of the pure metal for CO and CO{sub 2} hydrogenation. The oxide deposits were found to strongly enhance the reactivity of the Rh foil. The rates of methane formation were promoted by up to 15 fold with the maximum in rate enhancement occurring at oxide coverages of approximately 0.5 ML. TiOx TaOx, and NbOx were the most effective promoters and were stable in the highest oxidation states during both reactions (compared to VOx, WOx, and FeOx). The trend in promoter effectiveness was attributed to the direct relationship between oxidation state and Lewis acidity. Bonding at the metal oxide/metal interface between the oxygen end of adsorbed CO and the Lewis acidic oxide was postulated to facilitate C-O bond dissociation and subsequent hydrogenation. 192 refs.

Boffa, A.B. [Univ. of California, Berkeley, CA (United States). Dept. of Chemistry; [Lawrence Berkeley Lab., CA (United States). Materials Sciences Div.

1994-07-01T23:59:59.000Z

7

Total oxidation of carbon monoxide and methane over transition metal-fluorite oxide composite catalysts. I. Catalyst composition and activity  

SciTech Connect (OSTI)

A novel metal oxide composite catalyst for the total oxidation of carbon monoxide and methane was prepared by combining fluorite oxides with active transition metals. The fluorite oxides, such as ceria and zirconia, are oxygen-ion-conducting materials having catalytic properties usually at high temperatures. Active base metal catalysts, such as copper, were used as additives to promote the catalytic properties of these oxides. The contact of the two types of materials gave rise to a high active oxidation catalyst. At a space velocity of about 42,000 h{sup {minus}1}, complete carbon monoxide oxidation in air occurred at room temperature on the Au{sub 0.05}[Ce(La)]{sub 0.95}L{sub x} catalyst and at ca. 100{degrees}C on Cu-Ce-O composite catalysts. At the same space velocity, total oxidation of methane on the Cu-Ce-O catalyst doped with La{sub 2}O{sub 3} or SrO took place at ca. 550{degrees}C. The specific carbon monoxide oxidation activity of the Cu-Ce-O catalyst was several orders of magnitude higher than that of conventional copper-based catalysts and comparable or superior to platinum catalysts. This type of composite catalyst also showed excellent resistance to water vapor poisoning. The enhanced catalyst activity and stability resulted from strong interaction of the transition metal and fluorite oxide materials. 44 refs., 14 figs., 5 tabs.

Liu, W.; Flytzani-Stephanopoulos, F. [Tufts Univ., Medford, MA (United States)] [Tufts Univ., Medford, MA (United States)

1995-05-01T23:59:59.000Z

8

Tar Reforming in Model Gasifier Effluents: Transition Metal/Rare Earth Oxide Catalysts  

Science Journals Connector (OSTI)

Tar Reforming in Model Gasifier Effluents: Transition Metal/Rare Earth Oxide Catalysts ... So in this work we investigated the action of transition metal oxides (TMOs) other than Ni (e.g., Fe, Mn) mixed with REOs for tar reforming, at a medium temperature range (923–1073 K) and under conditions where direct reforming would dominate. ... The heated gas mixture passed through a 1/2” stainless steel tube containing 0.2–1 g of catalyst (40–60 mesh size) diluted with mullite and positioned between beds of ?-Al2O3. ...

Rui Li; Amitava Roy; Joseph Bridges; Kerry M. Dooley

2014-04-24T23:59:59.000Z

9

Metal Oxides  

Science Journals Connector (OSTI)

Metal oxides are the class of materials having the widest application in gas sensors. This chapter presents information related to the application of various metal oxides in gas sensors designed on different p...

Ghenadii Korotcenkov

2013-01-01T23:59:59.000Z

10

Understanding the NMR shifts in paramagnetic transition metal oxides using density functional theory calculations  

E-Print Network [OSTI]

obvious. In this paper, we show by means of density functional theory DFT calcula- tions that a rationalUnderstanding the NMR shifts in paramagnetic transition metal oxides using density functional functional theory DFT calculations in the generalized gradient approximation. For each compound, we calculate

Ceder, Gerbrand

11

Methane-to-Methanol Conversion by Gas-Phase Transition Metal Oxide Cations: Experiment and Theory  

E-Print Network [OSTI]

Methane-to-Methanol Conversion by Gas-Phase Transition Metal Oxide Cations: Experiment and Theory Ricardo B. Metz Department of Chemistry, University of Massachusetts, Amherst, MA 01003 USA Abstract Gas such as methanol has attracted great experimental and theoretical interest due to its importance as an industrial

Metz, Ricardo B.

12

Borohydride reduction: A technique to synthesize nanosize transition metal oxides and nanocomposites  

SciTech Connect (OSTI)

This paper summarizes recent studies of using borohydride reduction to synthesize W, transition metal oxides such as WO{sub 2} and MoO{sub 2}, and Fe-Al{sub x}B{sub y}O{sub z}

Zhu, Yuntian T.; Lowe, T.C.; Stout, M.G. [Los Alamos National Lab., NM (United States); Manthiram, A.; Guggilla, S. [Texas Univ., Austin, TX (United States). Center for Materials Science and Engineering

1996-06-01T23:59:59.000Z

13

Roughening transition of grain boundaries in metals and oxides  

Science Journals Connector (OSTI)

Extensive theoretical analysis and experimental observations show surface roughening transitions of crystals. The surface roughening is characterized by step free energy, which gradually decreases to 0 at the roughening

D. Y. Yoon; Y. K. Cho

2005-02-01T23:59:59.000Z

14

Correlation effects in (111) bilayers of perovskite transition-metal oxides  

SciTech Connect (OSTI)

We investigate the correlation-induced Mott, magnetic, and topological phase transitions in artificial (111) bilayers of perovskite transition-metal oxides LaAuO3 and SrIrO3 for which the previous density-functional theory calculations predicted topological insulating states. Using the dynamical-mean-field theory with realistic band structures and Coulomb interactions, LaAuO3 bilayer is shown to be far away from a Mott insulating regime, and a topological-insulating state is robust. On the other hand, SrIrO3 bilayer is on the verge of an orbital-selective topological Mott transition and turns to a trivial insulator by an antiferromagnetic ordering. Oxide bilayers thus provide a novel class of topological materials for which the interplay between the spin-orbit coupling and electron-electron interactions is a fundamental ingredient.

Okamoto, Satoshi [ORNL] [ORNL; Zhu, Wenguang [University of Science and Technology of China] [University of Science and Technology of China; Nomura, Yusuke [University of Tokyo, Japan] [University of Tokyo, Japan; Arita, R. [University of Tokyo, Japan] [University of Tokyo, Japan; Xiao, Di [Carnegie Mellon University (CMU)] [Carnegie Mellon University (CMU); Nagaosa, Naoto [University of Tokyo, Japan] [University of Tokyo, Japan

2014-01-01T23:59:59.000Z

15

Synthesis and structural, magnetic, thermal, and transport properties of several transition metal oxides and aresnides  

SciTech Connect (OSTI)

Oxide compounds containing the transition metal vanadium (V) have attracted a lot of attention in the field of condensed matter physics owing to their exhibition of interesting properties including metal-insulator transitons, structural transitions, ferromagnetic and antiferromagnetic orderings, and heavy fermion behavior. Binary vanadium oxides V{sub n}O{sub 2n-1} where 2 {le} n {le} 9 have triclinic structures and exhibit metal-insulator and antiferromagnetic transitions. The only exception is V{sub 7}O{sub 13} which remains metallic down to 4 K. The ternary vanadium oxide LiV{sub 2}O{sub 4} has the normal spinel structure, is metallic, does not undergo magnetic ordering and exhibits heavy fermion behavior below 10 K. CaV{sub 2}O{sub 4} has an orthorhombic structure with the vanadium spins forming zigzag chains and has been suggested to be a model system to study the gapless chiral phase. These provide great motivation for further investigation of some known vanadium compounds as well as to explore new vanadium compounds in search of new physics. This thesis consists, in part, of experimental studies involving sample preparation and magnetic, transport, thermal, and x-ray measurements on some strongly correlated eletron systems containing the transition metal vanadium. The compounds studied are LiV{sub 2}O{sub 4}, YV{sub 4}O{sub 8}, and YbV{sub 4}O{sub 8}. The recent discovery of superconductivity in RFeAsO{sub 1-x}F{sub x} (R = La, Ce, Pr, Gd, Tb, Dy, Sm, and Nd), and AFe{sub 2}As{sub 2} (A = Ba, Sr, Ca, and Eu) doped with K, Na, or Cs at the A site with relatively high T{sub c} has sparked tremendous activities in the condensed matter physics community and a renewed interest in the area of superconductivity as occurred following the discovery of the layered cuprate high T{sub c} superconductors in 1986. To discover more superconductors with hopefully higher T{sub c}'s, it is extremely important to investigate compounds having crystal structures related to the compounds showing high T{sub c} superconductivity. Along with the vanadium oxide compounds described before, this thesis describes our investigations of magnetic, structural, thermal and transport properties of EuPd{sub 2}Sb{sub 2} single crystals which have a crystal structure closely related to the AFe{sub 2}As{sub 2} compounds and also a study of the reaction kinetics of the formation of LaFeAsO{sub 1-x}F{sub x}.

Das, Supriyo

2010-05-16T23:59:59.000Z

16

Electrical conductivity in oxygen-deficient phases of transition metal oxides from first-principles calculations.  

SciTech Connect (OSTI)

Density-functional theory calculations, ab-initio molecular dynamics, and the Kubo-Greenwood formula are applied to predict electrical conductivity in Ta2Ox (0x5) as a function of composition, phase, and temperature, where additional focus is given to various oxidation states of the O monovacancy (VOn; n=0,1+,2+). Our calculations of DC conductivity at 300K agree well with experimental measurements taken on Ta2Ox thin films and bulk Ta2O5 powder-sintered pellets, although simulation accuracy can be improved for the most insulating, stoichiometric compositions. Our conductivity calculations and further interrogation of the O-deficient Ta2O5 electronic structure provide further theoretical basis to substantiate VO0 as a donor dopant in Ta2O5 and other metal oxides. Furthermore, this dopant-like behavior appears specific to neutral VO cases in both Ta2O5 and TiO2 and was not observed in other oxidation states. This suggests that reduction and oxidation reactions may effectively act as donor activation and deactivation mechanisms, respectively, for VO0 in transition metal oxides.

Bondi, Robert James; Desjarlais, Michael Paul; Thompson, Aidan Patrick; Brennecka, Geoffrey L.; Marinella, Matthew

2013-09-01T23:59:59.000Z

17

Strain induced electronic structure changes in magnetic transition metal oxides thin films  

SciTech Connect (OSTI)

We show that the angular dependence of x-ray magnetic circular dichroism (XMCD) is strongly sensitive to strain-induced electronic structure changes in magnetic transition metal oxides. We observe a pronounced dependence of the XMCD spectral shape on the experimental geometry as well as nonvanishing XMCD with distinct spectral features in transverse geometry in compressively strained MnCr{sub 2}O{sub 4} films. The angular dependent XMCD can be described as a sum over an isotropic and anisotropic contribution, the latter linearly proportional to the axial distortion due to strain. The XMCD spectra are well reproduced by atomic multiplet calculations.

van der Laan, G.; Chopdekar, R.V.; Suzuki, Y.; Arenholz, E.

2010-07-08T23:59:59.000Z

18

Synthesis of transition metal nitride by nitridation of metastable oxide precursor  

SciTech Connect (OSTI)

Metastable transition metal oxides were used as precursors to synthesize transition metal nitrides at low temperature. Amorphous MoO{sub 2} was prepared by reduction of (NH{sub 4}){sub 6}Mo{sub 7}O{sub 24} solution with hydrazine. As-synthesized amorphous MoO{sub 2} was transformed into fcc {gamma}-Mo{sub 2}N at 400 Degree-Sign C and then into hexagonal {delta}-MoN by further increasing the temperature to 600 Degree-Sign C under a NH{sub 3} flow. The nitridation temperature employed here is much lower than that employed in nitridation of crystalline materials, and the amorphous materials underwent a unique nitridation process. Besides this, the bimetallic nitride Ni{sub 2}Mo{sub 3}N was also synthesized by nitridating amorphous bimetallic precursor. These results suggested that the nitridation of amorphous precursor possessed potential to be a general method for synthesizing many interstitial metallic compounds, such as nitrides and carbides at low temperature. - graphical abstract: Amorphous oxide was used as new precursor to prepare nitride at low temperature. Pure {gamma}-Mo{sub 2}N and {delta}-MoN were obtained at 400 Degree-Sign C and at 600 Degree-Sign C, respectively. Highlights: Black-Right-Pointing-Pointer We bring out a new method to synthesize transition metal nitrides at low temperature. Black-Right-Pointing-Pointer Both mono- and bimetallic molybdenum nitrides were synthesized at a mild condition. Black-Right-Pointing-Pointer The formation of two different molybdenum nitrides {gamma}-Mo{sub 2}N and {delta}-MoN can be controlled from the same metastable precursor. Black-Right-Pointing-Pointer The nitridation temperature was much lower than that reported from crystalline precursors. Black-Right-Pointing-Pointer The metastable precursor had different reaction process in comparison with crystalline precursor.

Wang, Huamin; Wu, Zijie; Kong, Jing [Key Laboratory of Advanced Energy Materials Chemistry (MOE), College of Chemistry, Nankai University, Tianjin 300071 (China)] [Key Laboratory of Advanced Energy Materials Chemistry (MOE), College of Chemistry, Nankai University, Tianjin 300071 (China); Wang, Zhiqiang, E-mail: zqwang@mail.nankai.edu.cn [Key Laboratory of Advanced Energy Materials Chemistry (MOE), College of Chemistry, Nankai University, Tianjin 300071 (China) [Key Laboratory of Advanced Energy Materials Chemistry (MOE), College of Chemistry, Nankai University, Tianjin 300071 (China); Tianjin Key Laboratory of Water Environment and Resources, Tianjin Normal University, No. 393 Binshui Road, Xiqing Dist., Tianjin 300387 (China); Zhang, Minghui, E-mail: zhangmh@nankai.edu.cn [Key Laboratory of Advanced Energy Materials Chemistry (MOE), College of Chemistry, Nankai University, Tianjin 300071 (China)] [Key Laboratory of Advanced Energy Materials Chemistry (MOE), College of Chemistry, Nankai University, Tianjin 300071 (China)

2012-10-15T23:59:59.000Z

19

Spectroscopic Studies of O-Vacancy Defects in Transition Metal Oxides  

SciTech Connect (OSTI)

Dielectrics comprised of nano-crystalline HfO{sub 2} in gate stacks with thin SiO{sub 2}/SiON interfacial transition regions display significant asymmetries with respect to trapping of Si substrate injected holes and electrons. Based on spectroscopic studies, and guided by ab initio theory, electron and hole traps in HfO{sub 2} and other transition metal elemental oxides are assigned to O-atom divacancies clustered at internal grain boundaries of nano-crystalline films. Engineering solutions in which grain boundary defects are suppressed include: (i) ultra-thin, <2 nm, HfO{sub 2} fims, (ii) chemically phase separated high HfO2 content silicate films, and (iii) non-crystalline Zr/Hf Si oxynitride films.

Lucovsky, G.; Luning, J.; Fleming, L.B.; Ulrich, M.D.; Rowe, J.E.; Seo, H.; Lee, S.; Lysaght, P.; Bersuker, G.

2009-06-03T23:59:59.000Z

20

Superconductors and Complex Transition Metal Oxides for Tunable THz Plasmonic Metamaterials  

SciTech Connect (OSTI)

The outline of this presentation are: (1) Motivation - Non-tunability of metal metamaterials; (2) Superconductors for temperature tunable metamaterials; (3) Ultrafast optical switching in superconductor metamaterials; (4) Controlling the conductivity with infrared pump beam; (5) Complex metal oxides as active substrates - Strontium Titanate; and (6) Conclusion. Conclusions are: (1) High Tc superconductors good for tunable and ultrafast metamaterials; (2) Large frequency and amplitude tunability in ultrathin superconductor films; (3) Such tunable properties cannot be accessed using metals; (4) Complex metal oxides can be used as active substrates - large tunability; (5) Complex oxides fail to address the issue of radiation losses in THz metamaterials.

Singh, Ranjan [Los Alamos National Laboratory; Xiong, Jie [Los Alamos National Laboratory; Azad, Md A. [Los Alamos National Laboratory; Yang, Hao [Los Alamos National Laboratory; Trugman, Stuart A. [Los Alamos National Laboratory; Jia, Quanxi [Los Alamos National Laboratory; Taylor, Antoinette [Los Alamos National Laboratory; Chen, Houtong [Los Alamos National Laboratory

2012-07-13T23:59:59.000Z

Note: This page contains sample records for the topic "transition metal oxide" 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.


21

Transition metal oxide improves overall efficiency and maintains performance with inexpensive metals.  

E-Print Network [OSTI]

of a typical device (middle); schematic energy diagram of interfacial layers PbS/MoOx, indicating carrier metals. A research team at the National Renewable Energy Laboratory (NREL) has demonstrated the overall conversion efficiency. This allows for inexpensive metals such as Al to be employed without loss

22

Transition Metal Ions in the Gas Phase  

Science Journals Connector (OSTI)

For several years we have been studying the chemistry of atomic transition metal ions with simple organic molecules. This research was ... examining the consequences of oxidation and reduction of transition metal...

Douglas P. Ridge

1982-01-01T23:59:59.000Z

23

Improved layered mixed transition metal oxides for Li-ion batteries  

SciTech Connect (OSTI)

Recent work in our laboratory has been directed towards development of mixed layered transition metal oxides with general composition Li[Ni, Co, M, Mn]O2 (M=Al, Ti) for Li ion battery cathodes. Compounds such as Li[Ni1/3Co1/3Mn1/3]O2 (often called NMCs) are currently being commercialized for use in consumer electronic batteries, but the high cobalt content makes them too expensive for vehicular applications such as electric vehicles (EV), plug-in hybrid electric vehicles (PHEVs), or hybrid electric vehicles (HEVs). To reduce materials costs, we have explored partial or full substitution of Co with Al, Ti, and Fe. Fe substitution generally decreases capacity and results in poorer rate and cycling behavior. Interestingly, low levels of substitution with Al or Ti improve aspects of performance with minimal impact on energy densities, for some formulations. High levels of Al substitution compromise specific capacity, however, so further improvements require that the Ni and Mn content be increased and Co correspondingly decreased. Low levels of Al or Ti substitution can then be used offset negative effects induced by the higher Ni content. The structural and electrochemical characterization of substituted NMCs is presented in this paper.

Doeff, Marca M.; Conry, Thomas; Wilcox, James

2010-03-05T23:59:59.000Z

24

Transition metal-catalyzed oxidation of atmospheric sulfur: Global implications for the sulfur budget  

E-Print Network [OSTI]

of the oxygen-17 excess (D17 O) of sulfate in the Arctic to quantify the sulfate source from aqueous SO2 (S concentrations, respectively. The solubility and oxidation state of these metals is determined by cloud liquid discrepancies with surface SO2 and sulfate observations in Europe. Oxygen isotope measurements of sulfate

Alexander, Becky

25

The interactions between transition metal nanoparticles and their metal-oxide supports are often critical for heterogeneous metal nanoparticle  

E-Print Network [OSTI]

for selective hydrogenations (2, 3), oxidations (3­5), and the water-gas shift (WGS) reaction (3, 6). Several to saturation kinetics, with added water affecting the kinetics of the RDS. We explored potential mechanistic oxygen from the support (21, 27). Perhaps most importantly, as Fig. 1A shows, water dramatically

Napp, Nils

26

Consistent LDA' + DMFT approach to the electronic structure of transition metal oxides: Charge transfer insulators and correlated metals  

SciTech Connect (OSTI)

We discuss the recently proposed LDA' + DMFT approach providing a consistent parameter-free treatment of the so-called double counting problem arising within the LDA + DMFT hybrid computational method for realistic strongly correlated materials. In this approach, the local exchange-correlation portion of the electron-electron interaction is excluded from self-consistent LDA calculations for strongly correlated electronic shells, e.g., d-states of transition metal compounds. Then, the corresponding double-counting term in the LDA' + DMFT Hamiltonian is consistently set in the local Hartree (fully localized limit, FLL) form of the Hubbard model interaction term. We present the results of extensive LDA' + DMFT calculations of densities of states, spectral densities, and optical conductivity for most typical representatives of two wide classes of strongly correlated systems in the paramagnetic phase: charge transfer insulators (MnO, CoO, and NiO) and strongly correlated metals (SrVO{sub 3} and Sr{sub 2}RuO{sub 4}). It is shown that for NiO and CoO systems, the LDA' + DMFT approach qualitatively improves the conventional LDA + DMFT results with the FLL type of double counting, where CoO and NiO were obtained to be metals. Our calculations also include transition-metal 4s-states located near the Fermi level, missed in previous LDA + DMFT studies of these monoxides. General agreement with optical and the X-ray experiments is obtained. For strongly correlated metals, the LDA' + DMFT results agree well with the earlier LDA + DMFT calculations and existing experiments. However, in general, LDA' + DMFT results give better quantitative agreement with experimental data for band gap sizes and oxygen-state positions compared to the conventional LDA + DMFT method.

Nekrasov, I. A., E-mail: nekrasov@iep.uran.ru; Pavlov, N. S.; Sadovskii, M. V. [Russian Academy of Sciences, Institute for Electrophysics, Ural Branch (Russian Federation)

2013-04-15T23:59:59.000Z

27

Metal oxide films on metal  

DOE Patents [OSTI]

A structure including a thin film of a conductive alkaline earth metal oxide selected from the group consisting of strontium ruthenium trioxide, calcium ruthenium trioxide, barium ruthenium trioxide, lanthanum-strontium cobalt oxide or mixed alkaline earth ruthenium trioxides thereof upon a thin film of a noble metal such as platinum is provided.

Wu, Xin D. (Los Alamos, NM); Tiwari, Prabhat (Los Alamos, NM)

1995-01-01T23:59:59.000Z

28

Semiconductor-To-Metal Transitions in Transition-Metal Compounds  

Science Journals Connector (OSTI)

The theory presented in a previous paper is applied to the transition-metal compounds which are known to exhibit semiconductor-to-metal transitions. In particular, the predictions of the theory are compared with the experimental results of Feinleib and Paul on V2O3. Very good agreement is obtained for the magnitude of the energy gap and for its pressure and stress coefficients. The theory appears to be consistent with the available data on the other oxides of vanadium and titanium as well. Band models for all of these compounds are suggested. The effects of spin-disorder scattering and broadening, polaron formation, and non-stoichiometry are considered quantitatively.

David Adler; Julius Feinleib; Harvey Brooks; William Paul

1967-03-15T23:59:59.000Z

29

High-temperature desulfurization of gasifier effluents with rare earth and rare earth/transition metal oxides  

SciTech Connect (OSTI)

We have improved the application of mixed rare-earth oxides (REOs) as hot gas desulfurization adsorbents by impregnating them on stable high surface area supports and by the inclusion of certain transition metal oxides. We report comparative desulfurization experiments at high temperature (900 K) using a synthetic biomass gasifier effluent containing 0.1 vol % H{sub 2}S, along with H{sub 2}, CO{sub 2}, and water. More complex REO sorbents outperform the simpler CeO{sub 2}/La{sub 2}O{sub 3} mixtures, in some cases significantly. Supporting REOs on Al{sub 2}O{sub 3} (?20 wt % REO) or ZrO{sub 2} actually increased the sulfur capacities found after several cycles on a total weight basis. Another major increase in sulfur capacity took place when MnO{sub x} or FeO{sub x} is incorporated. Apparently most of the Mn or Fe is dispersed on or near the surface of the mixed REOs because the capacities with REOs greatly exceeded those of Al{sub 2}O{sub 3}-supported MnO{sub x} or FeO{sub x} alone at these conditions. In contrast, incorporating Cu has little effect on sulfur adsorption capacities. Both the REO and transition metal/REO adsorbents could be regenerated completely using air for at least five repetitive cycles.

Dooley, Kerry M.; Kalakota, Vikram; Adusumilli, Sumana

2011-01-01T23:59:59.000Z

30

Oxidative dehydrogenation (ODH) of ethane with O[subscript 2] as oxidant on selected transition metal-loaded zeolites  

SciTech Connect (OSTI)

Ni-, Cu-, and Fe-loaded acidic and basic Y zeolites were synthesized, and their catalytic properties for oxidative dehydrogenation of ethane (ODHE) to ethylene were characterized. Acidic Ni-loaded Y zeolite exhibits an ethylene productivity of up to 108 g{sub C{sub 2}H{sub 4}}g{sub cat}{sup -1} h{sup -1} with a selectivity of {approx}75%. Acidic Cu- and Fe-loaded Y zeolites have an ethylene productivity of up to 0.37 g{sub C{sub 2}H{sub 4}}g{sub cat}{sup -1} h{sup -1} and a selectivity of {approx}50%. For the same metal, the acidity of the zeolite favors both ODHE productivity and ethylene selectivity. Extended X-ray absorption fine structure (EXAFS) studies show that Ni, present in particles on Ni/HY during the ODHE catalytic process, contains both Ni-Ni and Ni-O bonds, and that the ratio of oxidized Ni versus metallic Ni increases with the temperature. The insights these studies provide into the ODHE reaction mechanism are discussed.

Lin, Xufeng; Hoel, Cathleen A.; Sachtler, Wolfgang M.H.; Poeppelmeier, Kenneth R.; Weitz, Eric; (NWU)

2009-09-14T23:59:59.000Z

31

Oligocyclopentadienyl transition metal complexes  

SciTech Connect (OSTI)

Synthesis, characterization, and reactivity studies of oligocyclopentadienyl transition metal complexes, namely those of fulvalene, tercyclopentadienyl, quatercyclopentadienyl, and pentacyclopentadienyl(cyclopentadienyl) are the subject of this account. Thermal-, photo-, and redox chemistries of homo- and heteropolynuclear complexes are described.

de Azevedo, Cristina G.; Vollhardt, K. Peter C.

2002-01-18T23:59:59.000Z

32

Transition-Metal Hydrides  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Transition-Metal Hydride Electrochromics Transition-Metal Hydride Electrochromics A new type of electrochromic hydride material has interesting and unusual properties. Thin Ni-Mg films, for example, are mirror-like in appearance and have very low visible transmittance. On exposure to hydrogen gas or on reduction in alkaline electrolyte, the films become transparent. The transition is believed to result from formation of nickel magnesium hydride, Mg2NiH4. Switchable mirrors based on rare earth hydrides were discovered in 1996 at Vrije University in the Netherlands, Rare earth-magnesium alloy films were subsequently found to be superior to the pure lanthanides in maximum transparency and mirror-state reflectivity by Philips Laboratories. The newer transition-metal types which use less expensive and less reactive materials were discovered at LBNL. This has now become a very active area of study with a network of researchers.

33

Functionalized Silicone Nanospheres: Synthesis, Transition Metal...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Functionalized Silicone Nanospheres: Synthesis, Transition Metal Immobilization, and Catalytic Applications. Functionalized Silicone Nanospheres: Synthesis, Transition Metal...

34

Mechanism of oxygen reduction reaction on transition metal oxide catalysts for high temperature fuel cells  

E-Print Network [OSTI]

The solid oxide fuel cell (SOFC) with its high energy conversion efficiency, low emissions, silent operation and its ability to utilize commercial fuels has the potential to create a large impact on the energy landscape. ...

La O', Gerardo Jose Cordova

2008-01-01T23:59:59.000Z

35

Interplay between electronic structure and catalytic activity in transition metal oxide model system  

E-Print Network [OSTI]

The efficiency of many energy storage and conversion technologies, such as hydrogen fuel cells, rechargeable metal-air batteries, and hydrogen production from water splitting, is limited by the slow kinetics of the oxygen ...

Suntivich, Jin

2012-01-01T23:59:59.000Z

36

High Performance Ceramic Interconnect Material for Solid Oxide Fuel Cells (SOFCs): Ca- and Transition Metal-doped Yttrium Chromite  

SciTech Connect (OSTI)

The effect of transition metal substitution on thermal and electrical properties of Ca-doped yttrium chromite was investigated in relation to use as a ceramic interconnect in high temperature solid oxide fuel cells (SOFCs). 10 at% Co, 4 at% Ni, and 1 at% Cu substitution on B-site of 20 at% Ca-doped yttrium chromite led to a close match of thermal expansion coefficient (TEC) with that of 8 mol% yttria-stabilized zirconia (YSZ), and a single phase Y0.8Ca0.2Cr0.85Co0.1Ni0.04Cu0.01O3 remained stable between 25 and 1100 degree C over a wide oxygen partial pressure range. Doping with Cu significantly facilitated densification of yttrium chromite. Ni dopant improved both electrical conductivity and dimensional stability in reducing environments, likely through diminishing the oxygen vacancy formation. Substitution with Co substantially enhanced electrical conductivity in oxidizing atmosphere, which was attributed to an increase in charge carrier density and hopping mobility. Electrical conductivity of Y0.8Ca0.2Cr0.85Co0.1Ni0.04Cu0.01O3 at 900 degree C is 57 S/cm in air and 11 S/cm in fuel (pO2=5×10^-17 atm) environments. Chemical compatibility of doped yttrium chromite with other cell components was verified at the processing temperatures. Based on the chemical and dimensional stability, sinterability, and thermal and electrical properties, Y0.8Ca0.2Cr0.85Co0.1Ni0.04Cu0.01O3 is suggested as a promising SOFC ceramic interconnect to potentially overcome technical limitations of conventional acceptor-doped lanthanum chromites.

Yoon, Kyung J.; Stevenson, Jeffry W.; Marina, Olga A.

2011-10-15T23:59:59.000Z

37

STUDY MAGNETIC EXCITATIONS IN DOPED TRANSITION METAL OXIDES USING INELASTIC NEUTRON SCATTERING  

SciTech Connect (OSTI)

Understanding the interplay between magnetism and superconductivity continues to be a “hot” topic in modern condensed matter physics. The discovery of high-temperature superconductivity in iron-based materials in 2008 provided an unique opportunity to compare and contrast these materials with traditional high-Tc copper oxide superconductors. Neutron scattering plays an important role in determining the dynamical spin properties in these materials. This proposal is a continuation of previous DOE supported proposal. This report summarizes the final progress we have made over from May 2005 till Aug. 2013. Overall, we continue to carry out extensive neutron scattering experiments on Fe-based materials, focusing on understanding their magnetic properties. In addition, we have established a materials laboratory at UT that has allowed us to grow these superconductors. Because neutron scattering typically demands a large amount of samples, by growing these materials in our own laboratory, we can now pursuit neutron scattering experiments over the entire electronic phase diagram, focusing on regions of interests. The material synthesis laboratory at UT was established entirely with the support of DOE funding. This not only allowed us to carry out neutron scattering experiments, but also permit us to provide samples to other US/International collaborators for studying these materials.

Dai, Pengcheng

2014-02-18T23:59:59.000Z

38

Lithium metal oxide electrodes for lithium batteries  

DOE Patents [OSTI]

An uncycled electrode for a non-aqueous lithium electrochemical cell including a lithium metal oxide having the formula Li.sub.(2+2x)/(2+x)M'.sub.2x/(2+x)M.sub.(2-2x)/(2+x)O.sub.2-.delta., in which 0.ltoreq.x<1 and .delta. is less than 0.2, and in which M is a non-lithium metal ion with an average trivalent oxidation state selected from two or more of the first row transition metals or lighter metal elements in the periodic table, and M' is one or more ions with an average tetravalent oxidation state selected from the first and second row transition metal elements and Sn. Methods of preconditioning the electrodes are disclosed as are electrochemical cells and batteries containing the electrodes.

Thackeray, Michael M. (Naperville, IL); Kim, Jeom-Soo (Naperville, IL); Johnson, Christopher S. (Naperville, IL)

2008-01-01T23:59:59.000Z

39

Magnetism in Transition Metals  

Science Journals Connector (OSTI)

An attempt is made to distinguish "band-type magnetization" from "alignment-type magnetization" on the basis of whether the local moments associated with the Wannier functions on the atom sites are "induced" or "permanent." In general, the local moment is partially induced and partially permanent, and a criterion is suggested: A local moment is defined to be of the permanent variety if in the presence of magnetic forces (supposed characteristic of the crystal in a given circumstance) tending to produce a moment in one sense (z^, say) of a direction, it can maintain itself (perhaps altered in magnitude, however) in the opposite sense (-z^), as well as in z^. The internal mechanisms tending to produce permanent moments are simplified to just the Hcorr of Anderson, and the external inducing mechanism are the Heisenberg interaction and a magnetic field, Hspin, say. If Hcorr dominates Hspin, then it is shown that a local moment can maintain itself to the polarizing tendencies (whence an alignment type of magnetization calculation is appropriate), but if Hspin dominates Hcorr, then the local moment has only one sense possible in this environment (and a band type of calculation is appropriate). It is suggested that this distinction is relevant to transition metals.

M. Bailyn

1965-09-13T23:59:59.000Z

40

Selenophene transition metal complexes  

SciTech Connect (OSTI)

This research shows that selenophene transition metal complexes have a chemistry that is similar to their thiophene analogs. Selenophene coordination has been demonstrated and confirmed by molecular structure in both the {eta}{sup 5}- and the {eta}{sup 1}(Se)-coordination modes. The reaction chemistry of selenophene complexes closely resembles that of the analogous thiophene complexes. One major difference, however, is that selenophene is a better donor ligand than thiophene making the selenophene complexes more stable than the corresponding thiophene complexes. The {sup 77}Se NMR chemical shift values for selenophene complexes fall within distinct regions primarily depending on the coordination mode of the selenophene ligand. In the final paper, the C-H bond activation of {eta}{sup 1}(S)-bound thiophenes, {eta}{sup 1}(S)-benzothiophene and {eta}{sup 1}(Se)-bound selenophenes has been demonstrated. The deprotonation and rearrangement of the {eta}{sup 1}(E)-bound ligand to the carbon bound L-yl complex readily occurs in the presence of base. Reprotonation with a strong acid gives a carbene complex that is unreactive towards nucleophilic attack at the carbene carbon and is stable towards exposure to air. The molecular structure of [Cp(NO)(PPh{sub 3})Re(2-benzothioenylcarbene)]O{sub 3}SCF{sub 3} was determined and contains a Re-C bond with substantial double bond character. Methyl substitution for the thienylcarbene or selenylcarbene gives a carbene that rearranges thermally to give back the {eta}{sup 1}(E)-bound complex. Based on these model reactions, a new mechanism for the H/D exchange of thiophene over the hydrodesulfurization catalyst has been proposed.

White, C.J.

1994-07-27T23:59:59.000Z

Note: This page contains sample records for the topic "transition metal oxide" 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

Deposition of Contiguous Metal Adlayer on Transition Metal Nanostructu...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

and Abstract Primary Lab Date Application 20100099012 Application 20100099012 Electrocatalyst Synthesized by Depositing a Contiguous Metal Adlayer on Transition Metal...

42

The metal–insulator transition: a perspective  

Science Journals Connector (OSTI)

...transition in condensed phases. Phys. Rev. B...M. J. 1982 The transition to the metallic...metalnon-metal transition in expanded metals...of electrons and ions in condensed matter...The metalnonmetal transition in disordered systems...1996c The changing phase of expanded metals...

1998-01-01T23:59:59.000Z

43

Magnetism in amorphous transition metals  

Science Journals Connector (OSTI)

Overall features of magnetism in amorphous transition metals have been investigated on the basis of a finite-temperature theory of the local-environment effect. It is shown that the simple ferromagnetism of Fe, Co, and Ni is drastically changed by structural disorder; amorphous transition metals form spin glasses (SG’s) for compositions near amorphous Fe (6.7?N?7.35), ferromagnets for compositions near amorphous Co (7.35?N?9.0), and paramagnetisms for compositions near amorphous Ni (9.0?N?10.0) where N is the number of d electrons. The SG is accompanied by formation of local ferromagnetic clusters for N?7.2, and shows reentrant behavior at the ferromagnetic boundary N?7.35. The ferromagnetism in amorphous transition metals is shown to be well explained by the main-peak position in the noninteracting densities of states. It is found that structural disorder enhances the Curie temperatures (TC) in the range 7.9?N?8.5 as compared with bcc and fcc structures. These results explain recent experimental data for the SG in Fe-rich amorphous alloys and the high TC in amorphous Co-Y alloys, but they are quite different from the early picture obtained for amorphous transition-metal–metalloid alloys.

Y. Kakehashi

1991-05-01T23:59:59.000Z

44

Time-Resolved XAFS Spectroscopic Studies of B-H and N-H Oxidative Addition to Transition Metal Catalysts Relevant to Hydrogen Storage  

SciTech Connect (OSTI)

Successful catalytic dehydrogenation of aminoborane, H3NBH3, prompted questions as to the potential role of N-H oxidative addition in the mechanisms of these processes. N-H oxidative addition reactions are rare, and in all cases appear to involve initial dative bonding to the metal by the amine lone pairs followed by transfer of a proton to the basic metal. Aminoborane and its trimethylborane derivative block this mechanism and, in principle, should permit authentic N-H oxidative attrition to occur. Extensive experimental work failed to confirm this hypothesis. In all cases either B-H complexation or oxidative addition of solvent C-H bonds dominate the chemistry.

Bitterwolf, Thomas E. [University of Idaho

2014-12-09T23:59:59.000Z

45

Metal-Nonmetal Transition in Metal-Ammonia Solutions  

Science Journals Connector (OSTI)

A review is given of the properties of metal-ammonia solutions together with a summary of the evidence for the existence of a metal-nonmetal transition.

J. C. THOMPSON

1968-10-01T23:59:59.000Z

46

Au/MxOy/TiO2 catalysts for CO oxidation: promotional effect of main-group, transition, and rare-earth metal oxide additives.  

SciTech Connect (OSTI)

Au/TiO2 catalysts are active for CO oxidation, but they suffer from high-temperature sintering of the gold particles, and few attempts have been made to promote or stabilize Au/TiO2. Our recent communication addressed these issues by loading gold onto Al2O3/TiO2 prepared via surface-sol-gel processing of Al(sec-OC4H9)3 on TiO2. In our current full paper, Au/Al2O3/TiO2 catalysts were prepared alternatively by thermal decomposition of Al(NO3)3 on TiO2 followed by loading gold, and the influences of the decomposition temperature and Al2O3 content were systematically surveyed. This facile method was subsequently extended to the preparation of a battery of metal oxide-modified Au/TiO2 catalysts virtually not reported. It was found that Au/TiO2 modified by CaO, NiO, ZnO, Ga2O3, Y2O3, ZrO2, La2O3, Pr2O3, Nd2O3, Sm2O3, Eu2O3, Gd2O3, Dy2O3, Ho2O3, Er2O3, or Yb2O3 could retain significant activity at ambient temperature even after aging in O2-He at 500 C, whereas unmodified Au/TiO2 lost its activity. Moreover, some 200 C-calcined promoted catalysts showed high activity even at about -100 C. The deactivation and regeneration of some of these new catalysts were studied. This work furnished novel catalysts for further fundamental and applied research.

Ma, Zhen [ORNL; Overbury, Steven {Steve} H [ORNL; Dai, Sheng [ORNL

2007-01-01T23:59:59.000Z

47

Characterization of the reactive and dissociative behavior of transition metal oxide cluster ions in the gas phase  

Science Journals Connector (OSTI)

The reactive and dissociative behavior of molybdenum and tungsten oxide cluster ions has been studied in the gas phase using a triple quadrupole mass spectrometer. Cluster ions (MO3) n ...

Simin Maleknia; Jennifer Brodbelt…

1991-05-01T23:59:59.000Z

48

Approximating Metal-Insulator Transitions  

E-Print Network [OSTI]

We consider quantum wave propagation in one-dimensional quasiperiodic lattices. We propose an iterative construction of quasiperiodic potentials from sequences of potentials with increasing spatial period. At each finite iteration step the eigenstates reflect the properties of the limiting quasiperiodic potential properties up to a controlled maximum system size. We then observe approximate metal-insulator transitions (MIT) at the finite iteration steps. We also report evidence on mobility edges which are at variance to the celebrated Aubry-Andre model. The dynamics near the MIT shows a critical slowing down of the ballistic group velocity in the metallic phase similar to the divergence of the localization length in the insulating phase.

C. Danieli; K. Rayanov; B. Pavlov; G. Martin; S. Flach

2014-05-06T23:59:59.000Z

49

Process for making transition metal nitride whiskers  

DOE Patents [OSTI]

A process for making metal nitrides, particularly titanium nitride whiskers, using a cyanide salt as a reducing agent for a metal compound in the presence of an alkali metal oxide. Sodium cyanide, various titanates and titanium oxide mixed with sodium oxide react to provide titanium nitride whiskers that can be used as reinforcement to ceramic composites. 1 fig., 1 tab.

Bamberger, C.E.

1988-04-12T23:59:59.000Z

50

METAL OXIDE NANOPARTICLES  

SciTech Connect (OSTI)

This chapter covers the fundamental science, synthesis, characterization, physicochemical properties and applications of oxide nanomaterials. Explains fundamental aspects that determine the growth and behavior of these systems, briefly examines synthetic procedures using bottom-up and top-down fabrication technologies, discusses the sophisticated experimental techniques and state of the art theory results used to characterize the physico-chemical properties of oxide solids and describe the current knowledge concerning key oxide materials with important technological applications.

FERNANDEZ-GARCIA,M.; RODGRIGUEZ, J.A.

2007-10-01T23:59:59.000Z

51

Lithium metal reduction of plutonium oxide to produce plutonium metal  

DOE Patents [OSTI]

A method is described for the chemical reduction of plutonium oxides to plutonium metal by the use of pure lithium metal. Lithium metal is used to reduce plutonium oxide to alpha plutonium metal (alpha-Pu). The lithium oxide by-product is reclaimed by sublimation and converted to the chloride salt, and after electrolysis, is removed as lithium metal. Zinc may be used as a solvent metal to improve thermodynamics of the reduction reaction at lower temperatures. Lithium metal reduction enables plutonium oxide reduction without the production of huge quantities of CaO--CaCl.sub.2 residues normally produced in conventional direct oxide reduction processes.

Coops, Melvin S. (Livermore, CA)

1992-01-01T23:59:59.000Z

52

Synthesis of transition metal carbonitrides  

DOE Patents [OSTI]

Transition metal carbonitrides (in particular, titanium carbonitride, TiC.sub.0.5 N.sub.0.5) are synthesized by a self-propagating reaction between the metal (e.g., titanium) and carbon in a nitrogen atmosphere. Complete conversion to the carbonitride phase is achieved with the addition of TiN as diluent and with a nitrogen pressure .gtoreq.0.6 MPa. Thermodynamic phase-stability calculations and experimental characterizations of quenched samples provided revealed that the mechanism of formation of the carbonitride is a two-step process. The first step involves the formation of the nonstoichiometric carbide, TiC.sub.0.5, and is followed by the formation of the product by the incorporation of nitrogen in the defect-structure carbide.

Munir, Zuhair A. R. (Davis, CA); Eslamloo-Grami, Maryam (Davis, CA)

1994-01-01T23:59:59.000Z

53

Laser Desorption/Ionization of Transition Metal Atoms and Oxides from Solid Argon Lester Andrews,*, Andreas Rohrbacher, Christopher M. Laperle, and Robert E. Continetti  

E-Print Network [OSTI]

, approximately 10% of the gas sample condensed on the 10K copper plate. For ablation a focused (10 cm f of the laser-ablated metal atoms and O2 in excess argon during condensation at 10 K, have been laser desorbed spectrometry. Adding the C6H5Br chromophore to the Ar/O2 gas mixture also enhanced the metal and oxide ion

Continetti, Robert E.

54

Metal-Insulator Transition in Metal—Rare-Gas Alloys  

Science Journals Connector (OSTI)

We present the results of electrical resistivity and optical absorption measurements for compositions spanning the metal-insulator transition in RbKr and CsXe alloys. The two transitions are similar and exhibit an apparently percolative character. No marked emergence of excitons accompanies the disappearance of conductivity. Spectral features associated with metallic conduction also persist through the transitions.

D. J. Phelps; R. Avci; C. P. Flynn

1975-01-06T23:59:59.000Z

55

NANO - "Green" metal oxides ... | ornl.gov  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

NANO - "Green" metal oxides ... Water and nano-sized particles isolated from trees, plants and algae are the ingredients of a new recipe for low-cost metal oxides that are widely...

56

Insulating gap in the transition-metal oxides: A calculation using the local-spin-density approximation with the on-site Coulomb U correlation correction  

Science Journals Connector (OSTI)

The electron-electron correlation has been considered by using the local-spin-density approximation (LSDA) with on-site Coulomb interaction (LSDA+U) in the first-principles discrete variational cluster method. Based on the correction to LSDA, we have carried out the self-consistent electronic-structure calculations for the strongly correlated electronic systems of NiO, CoO, and FeO. In contrast to LSDA, the LSDA+U calculations reveal the experimentally observed antiferromagnetic and insulating ground state. The values of the energy gap and the magnetic moment for these compounds are in good agreement with experimental results. The calculations suggest that the energy gap changes from the Mott-Hubbard characters for the early-3d-transition-metal monoxide to charge-transfer character for the late-3d-transition-metal monoxide.

Pan Wei and Zheng Qing Qi

1994-04-15T23:59:59.000Z

57

E-Print Network 3.0 - alkaline-earth metal oxides Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

differ in the nature of the angle... ). Weidner and Hamaya (1983) observed that the transition-metal oxides and the alkaline-earth oxides fail... ... Source: Price, G. David -...

58

Journal Article: Graphene physics and insulator-metal transition...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Graphene physics and insulator-metal transition in compressed hydrogen Citation Details Title: Graphene physics and insulator-metal transition in compressed hydrogen Authors:...

59

Observation of Metal-insulator and Metal-Metal Transitions in Hydrogen Iodide under Pressure  

Science Journals Connector (OSTI)

Hydrogen iodide has been studied up to pressures of 70 GPa at low temperatures in a diamondanvil cell. Electrical-conductivity and optical measurements have been used to observe pressure-induced phase transitions which are interpreted as follows: First a metal-insulator transition takes place in the molecular solid; with increased pressure a metal-metal molecular-to-atomic transition occurs. An additional transition due to intrinsic impurities has been observed. Implications for metallic hydrogen are discussed.

J. van Straaten and Isaac F. Silvera

1986-08-11T23:59:59.000Z

60

Vibronic spectroscopy of unsaturated transition metal complexes: CrC2H, CrCH3 , and NiCH3  

E-Print Network [OSTI]

to characterize diatomic transition metal oxides, nitrides, and carbides.8­22 In addition to these pure metallicVibronic spectroscopy of unsaturated transition metal complexes: CrC2H, CrCH3 , and NiCH3 Dale J investigation of small transition metal clusters and organo- metallic radicals is that these species serve

Morse, Michael D.

Note: This page contains sample records for the topic "transition metal oxide" 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.


61

Metal complexes of substituted Gable porphyrins as oxidation catalysts  

DOE Patents [OSTI]

Transition metal complexes of Gable porphyrins having two porphyrin rings connected through a linking group, and having on the porphyrin rings electron-withdrawing groups, such as halogen, nitro or cyano. These complexes are useful as catalysts for the oxidation of organic compounds, e.g. alkanes.

Lyons, James E. (Wallingford, PA); Ellis, Jr., Paul E. (Downingtown, PA); Wagner, Richard W. (Murrysville, PA)

1996-01-01T23:59:59.000Z

62

Metal complexes of substituted Gable porphyrins as oxidation catalysts  

DOE Patents [OSTI]

Transition metal complexes of Gable porphyrins are disclosed having two porphyrin rings connected through a linking group, and having on the porphyrin rings electron-withdrawing groups, such as halogen, nitro or cyano. These complexes are useful as catalysts for the oxidation of organic compounds, e.g. alkanes.

Lyons, J.E.; Ellis, P.E. Jr.; Wagner, R.W.

1996-01-02T23:59:59.000Z

63

Theory of bonding of transition metals to nontransition metals  

Science Journals Connector (OSTI)

We present a theory of the chemical bond in compounds consisting of both transition metals and nontransition metals. Chemical trends in the bonding properties are established by directly comparing the total energies of a large number of such compounds with the total energies of their constituents. These chemical trends are analyzed in terms of the s-, p-, and d-like state densities of the compounds and the constituents. Rather different types of bonding are shown to result when the atomic s and p levels of the nontransition metal lie above, below, and near the energy of the transition-metal d level. The heat of compound formation is shown to result from a competition between two simple physical effects: (1) the weakening of the transition-metal bonds by the lattice dilatation required for the accommodation of the nontransition metal, and (2) the increased bonding which results from the occupation of the bonding members of the hybrid states formed from the interaction between the transition-metal d states and the s-p states on the nontransition metal. Our theoretical values for the heats of formation of these compounds are generally similar to those given by Miedema's empirical formula. Distinctive aspects of the variation of the heat of formation with the number of valence electrons reveal, however, that the microscopic picture on which the empirical formula is based is quite different from that given by our self-consistent energy-band theory.

C. D. Gelatt; Jr.; A. R. Williams; V. L. Moruzzi

1983-02-15T23:59:59.000Z

64

Nanocomposite of graphene and metal oxide materials  

SciTech Connect (OSTI)

Nanocomposite materials comprising a metal oxide bonded to at least one graphene material. The nanocomposite materials exhibit a specific capacity of at least twice that of the metal oxide material without the graphene at a charge/discharge rate greater than about 10C.

Liu, Jun; Aksay, Ilhan A.; Choi, Daiwon; Wang, Donghai; Yang, Zhenguo

2012-09-04T23:59:59.000Z

65

Metallic to insulating transition in disordered pulsed laser deposited silicide thin films.  

E-Print Network [OSTI]

??A metal-to-insulating transition has been observed in iron, iron oxide, iron silicide and cobalt silicide thin films when deposited on Si substrate with a native… (more)

Abou Mourad, Houssam

2005-01-01T23:59:59.000Z

66

Methods of producing adsorption media including a metal oxide  

DOE Patents [OSTI]

Methods of producing a metal oxide are disclosed. The method comprises dissolving a metal salt in a reaction solvent to form a metal salt/reaction solvent solution. The metal salt is converted to a metal oxide and a caustic solution is added to the metal oxide/reaction solvent solution to adjust the pH of the metal oxide/reaction solvent solution to less than approximately 7.0. The metal oxide is precipitated and recovered. A method of producing adsorption media including the metal oxide is also disclosed, as is a precursor of an active component including particles of a metal oxide.

Mann, Nicholas R; Tranter, Troy J

2014-03-04T23:59:59.000Z

67

Three-Electrode Metal Oxide Reduction Cell  

DOE Patents [OSTI]

A method of electrochemically reducing a metal oxide to the metal in an electrochemical cell is disclosed along with the cell. Each of the anode and cathode operate at their respective maximum reaction rates. An electrolyte and an anode at which oxygen can be evolved, and a cathode including a metal oxide to be reduced are included as is a third electrode with independent power supplies connecting the anode and the third electrode and the cathode and the third electrode.

Dees, Dennis W. (Downers Grove, IL); Ackerman, John P. (Downers Grove, IL)

2005-06-28T23:59:59.000Z

68

Three-electrode metal oxide reduction cell  

DOE Patents [OSTI]

A method of electrochemically reducing a metal oxide to the metal in an electrochemical cell is disclosed along with the cell. Each of the anode and cathode operate at their respective maximum reaction rates. An electrolyte and an anode at which oxygen can be evolved, and a cathode including a metal oxide to be reduced are included as is a third electrode with independent power supplies connecting the anode and the third electrode and the cathode and the third electrode.

Dees, Dennis W. (Downers Groves, IL); Ackerman, John P. (Downers Grove, IL)

2008-08-12T23:59:59.000Z

69

Direct electrochemical reduction of metal-oxides  

DOE Patents [OSTI]

A method of controlling the direct electrolytic reduction of a metal oxide or mixtures of metal oxides to the corresponding metal or metals. A non-consumable anode and a cathode and a salt electrolyte with a first reference electrode near the non-consumable anode and a second reference electrode near the cathode are used. Oxygen gas is produced and removed from the cell. The anode potential is compared to the first reference electrode to prevent anode dissolution and gas evolution other than oxygen, and the cathode potential is compared to the second reference electrode to prevent production of reductant metal from ions in the electrolyte.

Redey, Laszlo I. (Downers Grove, IL); Gourishankar, Karthick (Downers Grove, IL)

2003-01-01T23:59:59.000Z

70

Graphene/metal Oxide Nanocomposites for Li-ion Batteries  

Science Journals Connector (OSTI)

Our work focuses on preparing the graphene/metal oxide nanocomposites by facile methold and exploring the graphene/metal oxide composites with unique structural or compositions for...

Liang, Junfei; Li, Lidong; Guo, Lin

71

Understanding Atom Probe Tomography of Oxide-Supported Metal...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Atom Probe Tomography of Oxide-Supported Metal Nanoparticles by Correlation with Atomic Resolution Electron Understanding Atom Probe Tomography of Oxide-Supported Metal...

72

Intrasphere and extrasphere effects of the influence of ammine complexes of transition metals on their catalytic activity in reactions of oxidation of manganese sulfate to the dioxide by atmospheric oxygen  

SciTech Connect (OSTI)

Manganese(II) sulfate is a waste product from the large-tonnage redox process for production of anthraquinone from aniline. Recovery of the original manganese dioxide and removal of manganese(II) sulfate from the wastewaters are economically and ecologically necessary. Liquid-phase low-temperature conversion of manganese(II) sulfate by the action of atmospheric oxygen blown through an aqueous solution of the salt containing ammine complexes of transition metals was studied earlier. It was shown that it does not depend only on intrasphere cations or extrasphere anions; it may be influenced by the effects of their interactions. The purpose of the present work was to study this influence in a complete factorial experiment of the CFE-3T type. It was found that homogeneous catalysis of oxidation of manganese(II) sulfate by atmospheric oxygen in presence of transition-metal ammines is determined to a considerable extent by the effects of pair interactions between complex-forming cations and extrasphere anions.

Eremeev, A.P.; Veselovskii, P.F.

1986-12-10T23:59:59.000Z

73

Catalytic production of metal carbonyls from metal oxides  

DOE Patents [OSTI]

This invention relates to the formation of metal carbonyls from metal oxides and specially the formation of molybdenum carbonyl and iron carbonyl from their respective oxides. Copper is used here in admixed form or used in chemically combined form as copper molybdate. The copper/metal oxide combination or combined copper is utilized with a solvent, such as toluene and subjected to carbon monoxide pressure of 25 atmospheres or greater at about 150 to 260/sup 0/C. The reducing metal copper is employed in catalytic concentrations or combined concentrations as CuMoO/sub 4/ and both hydrogen and water present serve as promoters. It has been found that the yields by this process have been salutary and that additionally the catalytic metal may be reused in the process to good effect. 3 tables.

Sapienza, R.S.; Slegeir, W.A.; Foran, M.T.

1984-01-06T23:59:59.000Z

74

High surface area, electrically conductive nanocarbon-supported metal oxide  

DOE Patents [OSTI]

A metal oxide-carbon composite includes a carbon aerogel with an oxide overcoat. The metal oxide-carbon composite is made by providing a carbon aerogel, immersing the carbon aerogel in a metal oxide sol under a vacuum, raising the carbon aerogel with the metal oxide sol to atmospheric pressure, curing the carbon aerogel with the metal oxide sol at room temperature, and drying the carbon aerogel with the metal oxide sol to produce the metal oxide-carbon composite. The step of providing a carbon aerogel can provide an activated carbon aerogel or provide a carbon aerogel with carbon nanotubes that make the carbon aerogel mechanically robust.

Worsley, Marcus A; Han, Thomas Yong-Jin; Kuntz, Joshua D; Cervanted, Octavio; Gash, Alexander E; Baumann, Theodore F; Satcher, Jr., Joe H

2014-03-04T23:59:59.000Z

75

Metal-insulator transition in dilute alkali-metal systems  

Science Journals Connector (OSTI)

The metal-insulator transition is studied for dilute systems of alkali metals. Using a spin-split self-consistent band-structure approach, we find the transition density, a strikingly enhanced magnetic susceptibility, and the electron effective mass. The critical density nc is found to be given by the simple relation rsc=r0+2.8. Here rsc=[3(4?nc)]13 and r0 is the model potential radius which is roughly the radius of the neutral atom. The Mott criterion of nc13aB?0.25 (where aB is the appropriate Bohr orbit) is found to be inadequate for describing these systems. The predicted effective mass and magnetic susceptibility enhancements are largest for Li and become systematically smaller for the heavier alkalis. We compare our results for the transition density with two sets of experiments, namely the gas-liquid critical density and the metal-insulator transition for codeposited thick films of alkali-metal and rare-gas atoms. Good agreement is found in both cases.

J. H. Rose

1981-01-15T23:59:59.000Z

76

Alkane oxidation with porphyrins and metal complexes thereof having haloalkyl side chains  

DOE Patents [OSTI]

Transition metal complexes of meso-haloalkylporphyrins are disclosed, wherein the haloalkyl groups contain 2 to 8 carbon atoms have been found to be highly effective catalysts for oxidation of alkanes and for the decomposition of hydroperoxides. 7 figs.

Wijesekera, T.; Lyons, J.E.; Ellis, P.E. Jr.; Bhinde, M.V.

1998-06-23T23:59:59.000Z

77

Alkane oxidation with porphyrins and metal complexes thereof having haloalkyl side chains  

DOE Patents [OSTI]

Transition metal complexes of meso-haloalkylporphyrins, wherein the haloalkyl groups contain 2 to 8 carbon atoms have been found to be highly effective catalysts for oxidation of alkanes and for the decomposition of hydroperoxides.

Wijesekera, Tilak (Glen Mills, PA); Lyons, James E. (Wallingford, PA); Ellis, Jr., Paul E. (Downingtown, PA); Bhinde, Manoj V. (Boothwyn, PA)

1998-01-01T23:59:59.000Z

78

Process for etching mixed metal oxides  

DOE Patents [OSTI]

An etching process using dicarboxylic and tricarboxylic acids as chelating etchants for mixed metal oxide films such as high temperature superconductors and ferroelectric materials. Undesirable differential etching rates between different metal oxides are avoided by selection of the proper acid or combination of acids. Feature sizes below one micron, excellent quality vertical edges, and film thicknesses in the 100 Angstom range may be achieved by this method.

Ashby, Carol I. H. (Edgewood, NM); Ginley, David S. (Evergreen, CO)

1994-01-01T23:59:59.000Z

79

Nonmetal-metal transition in metal–molten-salt solutions  

Science Journals Connector (OSTI)

The method of ab initio molecular dynamics, based on finite-temperature density-functional theory, is used to study the nonmetal-metal transition in two different metal–molten-salt solutions, Kx(KCl)1-x and Nax(NaBr)1-x. As the excess metal concentration is increased the electronic density becomes delocalized and percolating conducting paths are formed, making a significant dc electrical conductivity possible. This marks the onset of the metallic regime. By calculating several electronic and structural properties, remarkable differences between the two solutions are observed. The anomalous behavior of Nax(NaBr)1-x, typical of all the Na-NaX solutions, is found to be related to the strong attractive interaction between the sodium ions and the excess electrons. © 1996 The American Physical Society.

Pier Luigi Silvestrelli; Ali Alavi; Michele Parrinello; Daan Frenkel

1996-05-15T23:59:59.000Z

80

(Electronic structure and reactivities of transition metal clusters)  

SciTech Connect (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

Note: This page contains sample records for the topic "transition metal oxide" 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

Corrosion behavior of mesoporous transition metal nitrides  

SciTech Connect (OSTI)

Transition metal nitrides (TMN) have many desirable characteristics such as high hardness and good thermal stability under reducing conditions. This work reports an initial survey of the chemical stability of mesoporous TMNs (TM=Nb, V, Cr and Ti) in water at 80 °C at neutral, acidic and alkaline pH. The mesoporous TMNs had specific surface areas of 25–60 m{sup 2}/g with average pore sizes ranging from 10 to 50 nm. The high surface areas of these materials enhance the rate of corrosion per unit mass over that of a bulk material, making detection of corrosion much easier. The products were characterized by Rietveld refinement of powder X-ray diffraction (PXRD) patterns and by scanning electron microscopy (SEM). Several nitrides have corrosion rates that are, within error, not distinguishable from zero (±1 Å/day). Of the nitrides examined, CrN appears to be the most corrosion resistant under acidic conditions. None of the nitrides studied are corrosion resistant under alkaline conditions. - Graphical abstract: Corrosion behavior of mesoporous transition metal nitrides (TM=Nb, V, Cr and Ti) in acidic and alkaline solutions at 80 °C for 2 weeks. Display Omitted - highlights: • Corrosion rates of mesoporous transition metal nitrides in aqueous solution is reported. • The mesoporous TMNs had surface areas of 25–60 m{sup 2}/g. • CrN is the most corrosion resistant under the conditions studied.

Yang, Minghui, E-mail: m.yang@cornell.edu [Department of Chemistry, Cornell University, Ithaca 14853-1301, NY (United States); Allen, Amy J.; Nguyen, Minh T. [Department of Chemistry, Cornell University, Ithaca 14853-1301, NY (United States); Ralston, Walter T. [College of Chemistry, University of California, Berkeley 94720-1460, CA (United States); MacLeod, Michelle J. [Department of Chemistry, Massachusetts Institute of Technology, Cambridge 02139-4307, MA (United States); DiSalvo, Francis J., E-mail: fjd3@cornell.edu [Department of Chemistry, Cornell University, Ithaca 14853-1301, NY (United States)

2013-09-15T23:59:59.000Z

82

Selective Catalytic Oxidation (SCO) of NH3 to N2 for Hot Exhaust Treatment  

Broader source: Energy.gov [DOE]

Investigation of a series of transition metal oxides and precious metal based catalysts for ammonia selective oxidation at low temperatures

83

Reactor process using metal oxide ceramic membranes  

DOE Patents [OSTI]

A reaction vessel for use in photoelectrochemical reactions includes as its reactive surface a metal oxide porous ceramic membrane of a catalytic metal such as titanium. The reaction vessel includes a light source and a counter electrode. A provision for applying an electrical bias between the membrane and the counter electrode permits the Fermi levels of potential reaction to be favored so that certain reactions may be favored in the vessel. The electrical biasing is also useful for the cleaning of the catalytic membrane. Also disclosed is a method regenerating a porous metal oxide ceramic membrane used in a photoelectrochemical catalytic process by periodically removing the reactants and regenerating the membrane using a variety of chemical, thermal, and electrical techniques. 2 figures.

Anderson, M.A.

1994-05-03T23:59:59.000Z

84

Chapter 14 - Metal oxide nanopowder  

Science Journals Connector (OSTI)

Research into soft chemical techniques has gained an importance for the synthesis of high quality advanced nanosized materials with desired properties at the low crystallization temperature. The closer interaction between the material chemists and alkoxide chemists has led to the molecular design of more suitable precursors, for fabrication of functional material has resulted in synergetic developments in both the fields. Metal alkoxide is a versatile precursor and is used for the synthesis of functional gradient nanomaterials, and characterization of materials was carried out in term of composition, microstructure and specific surface area. The write-up provides simple and convenient routes to many building blocks for assembling the structure with novel properties and its functional use in nanotechnology.

Taimur Athar

2015-01-01T23:59:59.000Z

85

Correlation between resistance-change effect in transition-metal oxides and secondary-electron contrast of scanning electron microscope images  

SciTech Connect (OSTI)

Conductive atomic-force microscopy (C-AFM) writing is attracting attention as a technique for clarifying the switching mechanism of resistive random-access memory by providing a wide area filled with filaments, which can be regarded as one filament with large radius. The writing area on a nickel-oxide (NiO) film formed by conductive atomic-force microscopy was observed by scanning electron microscope, and a correlation between the contrast in a secondary-electron image (SEI) and the resistance written by C-AFM was revealed. In addition, the dependence of the SEI contrast on the beam accelerating voltage (V{sub accel}) suggests that the resistance-change effect occurs near the surface of the NiO film. As for the effects of electron irradiation and vacuum annealing on the C-AFM writing area, it was shown that the resistance-change effect is caused by exchange of oxygen with the atmosphere at the surface of the NiO film. This result suggests that the low-resistance and high-resistance areas are, respectively, p-type Ni{sub 1+{delta}}O ({delta} < 0) and insulating (stoichiometric) or n-type Ni{sub 1+{delta}}O ({delta}{>=} 0).

Kinoshita, K.; Kishida, S. [Department of Information and Electronics, Graduate School of Engineering, Tottori University, 4-101 Koyama-Minami, Tottori 680-8552 (Japan); Tottori University Electronic Display Research Center, 522-2 Koyama-Kita, Tottori 680-0941 (Japan); Yoda, T. [Department of Information and Electronics, Graduate School of Engineering, Tottori University, 4-101 Koyama-Minami, Tottori 680-8552 (Japan)

2011-09-15T23:59:59.000Z

86

Partial oxidation of lower alkanes by active lattice oxygen of metal oxide systems: 2. Synthesis of solid contacts and syngas production in a pilot plant with a riser reactor  

Science Journals Connector (OSTI)

Metal oxide systems with a high lattice-oxygen content, which exhibit reversibility of oxidationreduction transitions, have been synthesized and characterized. Oxidant Solid Contacts have been prepared using t...

I. M. Gerzeliev; N. Ya. Usachev; A. Yu. Popov; S. N. Khadzhiev

2012-09-01T23:59:59.000Z

87

Metal-nonmetal transition in metal-ammonia solutions  

Science Journals Connector (OSTI)

In this paper we present a coherent physical picture of the metal-nonmetal transition in metal-ammonia solutions in the intermediate concentration range. We propose that in Li-NH3 and Na-NH3 solutions the metallic propagation regime is separated from a nonmetallic regime by a microscopically inhomogeneous regime in which the concentration fluctuates locally about either of two well-defined values M0 and M1, M0>M1, the local concentration remaining near M0 or M1 over radii approximately equal to the Debye short correlation length b for concentration fluctuations. Provided that the concentration-fluctuation decay length is much smaller than b, we can define a percolation problem in which a volume fraction C of the material is occupied by metallic regions of concentration M0, the remainder containing the low concentration M1 of dissociated electron-cation complexes. M0 and M1 constitute the upper and the lower bounds of the inhomogeneous regime, respectively, while C exhibits a linear dependence on M. This physical picture is borne out by concentration-fluctuation determinations based on chemical-potential measurements in Li and Na solutions and by small-angle x-ray and neutron scattering in Li solutions. Assuming that the phase-coherence length of the conduction electrons is shorter than b and having demonstrated that tunneling corrections are negligible, we can define local electronic structure and transport properties. The limits of the inhomogeneous regime were determined from a combination of concentration-fluctuation measurements, electrical conductivity, Hall effect, and paramagnetic susceptibility data to be M0=9 mole percent metal (MPM) and M1=2(13) MPM, which yield the C scale, C=[M-2(13)]6(23), for both Li-NH3 at 223°K and for Na-NH3 at 240°K. We have also established the consistency of our picture with the available magnetic data for Na solutions. An analysis of the electronic and the thermal transport properties was carried out in terms of an effective-medium theory, modified to account for scattering from the boundaries of the metallic clusters. For low values of the conductivity ratio (? 10-3) between the nonmetallic and the metallic regions the modified effective-medium theory is valid for C>0.4. In an attempt to mimic the features of continuous percolation, we have carried out numerical simulations of the conductivity in a simple cubic lattice incorporating correlation between metallic bonds. An excellent fit of the experimental conductivity data for Li and Na with the results of the numerical simulations has been obtained over a three order of magnitude variation of the conductivity throughout the entire inhomogeneous regime. A small systematic negative deviation of the conductivity from the predictions of the effective-medium theory for C>0.4 can be properly accounted for in terms of boundary scattering corrections resulting in b?15 Å for Li at 223°K and b?32 Å for Na at 240°K. The overall agreement of the experimental Hall effect, Hall mobility, thermalconductivity, and thermoelectric-power data with the effective-medium theory is good. The proposed inhomogeneous regime in Li and Na solutions resembles a macroscopic mixed phase at a concentration inside a coexistence curve but with mixing on a microscopic scale. The concentration fluctuations in the inhomogeneous state have nothing to do with critical fluctuations; nevertheless, this state seems to be closely associated with the occurrence of a phase separation.

Joshua Jortner and Morrel H. Cohen

1976-02-15T23:59:59.000Z

88

Magnetism at the surface of transition-metal alloys  

Science Journals Connector (OSTI)

We study magnetic properties of transition-metal atoms at the surface of transition-metal alloys. Using two simple models for the local environment dependence of the magnetic moment of transition-metal atoms in transition-metal alloys, we determine the magnetic moments in the first few atomic layers parallel to the surface for various alloy compositions. Results are presented for Ni in Cu-Ni alloys. Results for different surface directions are given. Segregation and short-range order are taken into account. One finds that the magnetic properties at the surface of the alloys are strongly affected by surface segregation. Furthermore, in view of our results one expects changes in the magnetic behavior of transition-metal alloys due to chemisorption. We expect that surface studies are a reasonable tool to study the dependence of magnetic moments on local atomic environment.

J. L. Morán-López; F. Brouers; K. H. Bennemann

1978-01-01T23:59:59.000Z

89

Transition metal-free olefin polymerization catalyst  

DOE Patents [OSTI]

Ethylene and/or propylene are polymerized to form high molecular weight, linear polymers by contacting ethylene and/or propylene monomer, in the presence of an inert reaction medium, with a catalyst system which consists essentially of (1) an aluminum alkyl component, such as trimethylaluminum, triethylaluminum, triisobutylaluminum, tri-n-octylaluminum and diethylaluminum hydride and (2) a Lewis acid or Lewis acid derivative component, such as B (C.sub.6 F.sub.5).sub.3, [(CH.sub.3).sub.2 N (H) (C.sub.6 H.sub.5)].sup.+ [B (C.sub.6 F.sub.5)4].sup.-, [(C.sub.2 H.sub.5).sub.3 NH].sup.+ [B C.sub.6 F.sub.5).sub.4 ],.sup.-, [C(C.sub.6 F.sub.5).sub.3 ].sup.+ [B(C.sub.6 F.sub.5).sub.4 ].sup.-, (C.sub.2 H.sub.5).sub.2 Al(OCH.sub.3), (C.sub.2 H.sub.5).sub.2 Al(2,6-di-t-butyl-4-methylphenoxide), (C.sub.2 H.sub.5)Al(2,6 -di-t-butylphenoxide).sub.2, (C.sub.2 H.sub.5).sub.2 Al(2,6-di-t-butylphonoxide) , 2,6 -di-t-butylphenol.multidot.methylaluminoxane or an alkylaluminoxane, and which may be completely free any transition metal component(s).

Sen, Ayusman (State College, PA); Wojcinski, II, Louis M. (State College, PA); Liu, Shengsheng (State College, PA)

2001-01-01T23:59:59.000Z

90

The strong reactions of Lewis-base noble-metals with vanadium and other acidic transition metals  

SciTech Connect (OSTI)

The noble metals often thought of as unreactive solids,react strongly with nearly 40% of the elements in the periodictable: group IIIB-VB transition metals, lanthanides, theactinides, and group IIIA-IVA non-transition metals. These strong reactions arise from increased bonding/electron transfer fromnonbonding electrons d electron pairs on the noble metal tovacant orbitals on V, etc. This effect is a generalized Lewis acid-base interaction. The partial Gibbs energy of V in the noblemetals has been measured as a function of concentration at a temperature near 1000C. Thermodynamics of the intermetallics are determined by ternary oxide equilibria, ternary carbide equilibria, and the high-temperature galvanic cell technique. These experimental methods use equilibrated solid composite mixtures in which grains of V oxides or of V carbides are interspersed with grains of V-NM(noble-metal) alloys. In equilibrium the activity of V in the oxide or the carbide equals the activity in the alloy. Consequently, the thermodynamics available in the literature for the V oxides and V carbides are reviewed. Test runs on the galvanic cell were attempted. The V oxide electrode reacts with CaF[sub 2], ThO[sub 2], YDT(0.85ThO[sub 2]-0.15YO[sub 1.5]), and LDT(0.85ThO[sub 2]- 0.15LaO[sub 1.5]) to interfere with the measured data observed toward the beginning of a galvanic cell experiment are the most accurate. The interaction of vanadium at infinite dilution in the noble-metals was determined.

Ebbinghaus, B.B.

1991-05-01T23:59:59.000Z

91

The strong reactions of Lewis-base noble-metals with vanadium and other acidic transition metals  

SciTech Connect (OSTI)

The noble metals often thought of as unreactive solids,react strongly with nearly 40% of the elements in the periodictable: group IIIB-VB transition metals, lanthanides, theactinides, and group IIIA-IVA non-transition metals. These strong reactions arise from increased bonding/electron transfer fromnonbonding electrons d electron pairs on the noble metal tovacant orbitals on V, etc. This effect is a generalized Lewis acid-base interaction. The partial Gibbs energy of V in the noblemetals has been measured as a function of concentration at a temperature near 1000C. Thermodynamics of the intermetallics are determined by ternary oxide equilibria, ternary carbide equilibria, and the high-temperature galvanic cell technique. These experimental methods use equilibrated solid composite mixtures in which grains of V oxides or of V carbides are interspersed with grains of V-NM(noble-metal) alloys. In equilibrium the activity of V in the oxide or the carbide equals the activity in the alloy. Consequently, the thermodynamics available in the literature for the V oxides and V carbides are reviewed. Test runs on the galvanic cell were attempted. The V oxide electrode reacts with CaF{sub 2}, ThO{sub 2}, YDT(0.85ThO{sub 2}-0.15YO{sub 1.5}), and LDT(0.85ThO{sub 2}- 0.15LaO{sub 1.5}) to interfere with the measured data observed toward the beginning of a galvanic cell experiment are the most accurate. The interaction of vanadium at infinite dilution in the noble-metals was determined.

Ebbinghaus, B.B.

1991-05-01T23:59:59.000Z

92

Tuning of the Metal-Insulator Transition via Alkali Adsorption  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Tuning of the Metal-Insulator Transition via Alkali Adsorption Print Tuning of the Metal-Insulator Transition via Alkali Adsorption Print Turning a material from an insulator to a metal, or vice versa, by light irradiation, exposure to electric or magnetic fields, or applying small changes in temperature, pressure, or doping-such intriguing control of a material's electronic properties is possible by exploiting strongly interacting or "correlated" electrons. Now a team of researchers from the University of Kiel in Germany and the ALS has found a novel, surprising way to continuously transform a layered metallic transition-metal compound, TaS2, into an insulator. Using angle-resolved photoemission spectroscopy (ARPES), they have demonstrated that adsorption of alkali atoms onto this material's surface gradually makes it more insulating, although in general, alkali adsorption should lead to more metallic behavior, as alkali atoms easily give away their loosely bound outermost electron.

93

Designing Semiconductor Metal Oxides for Photoelectrochemical Energy Conversion  

Science Journals Connector (OSTI)

Innovative materials hold the key for renewable energy conversion. In this talk, we will introduce our recent progress in semiconducting metal oxides, which underpin a number of...

Wang, Lianzhou

94

Transition Metal Sulfide Electrocatalysts for PEM Fuel Cells  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Transition Metal Sulfide Transition Metal Sulfide Electrocatalysts for PEM Fuel Cells Hua Zhang 1 , Ysmael Verde-Gómez 1 and Allan J. Jacobson 1 Alejandra Ramirez 2 and Russell R. Chianelli 2 1 Department of Chemistry, University of Houston Houston, TX 77204 2 Materials Research and Technology Institute, University of Texas at El Paso, El Paso, TX 79968 Transition Metal Sulfide Electrocatalysts for PEM Fuel Cells Hua Zhang 1 , Ysmael Verde-Gómez 1 and Allan J. Jacobson 1 Alejandra Ramirez 2 and Russell R. Chianelli 2 1 Department of Chemistry, University of Houston Houston, TX 77204 2 Materials Research and Technology Institute, University of Texas at El Paso, El Paso, TX 79968 March 21, 2003 Objectives ¾ Investigate non-platinum electro-catalysts with CO tolerance ¾ Focus on transition metal sulfides as electro-catalysts

95

Mechanisms of transition-metal gettering in silicon  

SciTech Connect (OSTI)

The atomic process, kinetics, and equilibrium thermodynamics underlying the gettering of transition-metal impurities in Si are reviewed from a mechanistic perspective. Methods for mathematical modeling of gettering are reviewed and illustrated. Needs for further research are discussed.

MYERS JR.,SAMUEL M.; SEIBT,M.; SCHROTER,W.

2000-03-23T23:59:59.000Z

96

Phase-Transfer Catalysis-Transition Metal Cocatalyzed Reactions  

Science Journals Connector (OSTI)

Transition metals are active catalysts for a variety of organic reactions. Sometimes they are also useful in conjunction with phase-transfer catalysts, particularly when hydroxide anions and other inorganic sp...

Charles M. Starks; Charles L. Liotta; Marc E. Halpern

1994-01-01T23:59:59.000Z

97

Controlled Doping of Transition Metal Cations in Alumina Pillared Clays  

Science Journals Connector (OSTI)

First, calcined Al-PILC was dispersed into an aqueous solution of sodium or ammonium ions. ... The ion-doped Al-PILC was then exchanged with an aqueous solution of transition metal salt at a pH of ?4.5 to replace Na+ or NH4+ ions by transition metal cations. ... Analytical techniques such as atomic absorption spectroscopy, X-ray diffraction, diffuse reflectance?ultraviolet?visible spectroscopy, as well as N2 adsorption were used to characterize the PILC products with and without the loading of metal ions. ...

H. Y. Zhu; Z. H. Zhu; G. Q. Lu

2000-05-31T23:59:59.000Z

98

Structure, adhesion, and stability of metal/oxide and oxide/oxide interfaces  

SciTech Connect (OSTI)

Studies of structural, electronic, and chemical properties of metal/oxide and oxide/oxide interfaces were performed on well-defined interfaces that created by depositing ultra-thin potassium and aluminum films and their oxides onto single crystal TiO[sub 2] and NiO surfaces. Work focused on determining the structure, growth mechanisms, and morphologies of metal and oxide films as they are deposited an single crystal oxide surfaces using RHEED and atomic force microscopy probing electronic structure, bonding and chemical interactions at the interfaces using x-ray and uv photoelectron spectroscopies (XPS, UPS) and Auger electron spectroscopy (AES), and understanding factors affecting stability and reactivity of the interface regions including the role of defects and impurities. Results indicate that kinetic effects have an important influence on interface structure and composition, and they also show that defects in the oxide substrate induce new electronic states at the interface which play a major role in cation-anion bonding and interface interactions. The results establish a link between electronic and chemical bonding properties and the interface structure and morphology, which is required to successfully manipulate the interfacial properties of advanced ceramic materials.

Lad, R.J.

1992-11-01T23:59:59.000Z

99

Structure, adhesion, and stability of metal/oxide and oxide/oxide interfaces  

SciTech Connect (OSTI)

During the past six months, we have begun our studies of the fundamental properties of metal/oxide and oxide/oxide heterogeneous interfaces which are being prepared by epitaxial growth of ultra-thin-films on single crystal TiO{sub 2} and NiO surfaces. A new ultra-high vacuum film growth chamber was assembled and coupled to an existing surface analysis chamber; a sample transfer system, metal deposition sources, and a RHEED systems with microchannel plate detection were constructed and implemented. Atomic Force Microscopy was used to characterize and refine the preparation procedures for the single crystal surfaces. The electronic structure of stoichiometric, oxygen-deficient, and potassium-covered TiO{sub 2} (110) surfaces was investigated. Preliminary results on the Al/TiO{sub 2} (110) system have been obtained. Two graduate students have begun thesis research on the project. 6 figs.

Lad, R.J.

1991-01-01T23:59:59.000Z

100

Biofuels production from hydrotreating of vegetable oil using supported noble metals, and transition metal carbide and nitride.  

E-Print Network [OSTI]

?? The focus of this research is to prepare non-sulfided hydrotreating catalysts, supported noble metal and transition metal carbide/ nitride, and evaluate their hydrocracking activities… (more)

Wang, Huali

2012-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "transition metal oxide" 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

Molten salt extraction process for the recovery of valued transition metals from land-based and deep-sea minerals  

DOE Patents [OSTI]

A process for extracting transition metals and particularly cobalt and manganese together with iron, copper and nickel from low grade ores (including ocean-floor nodules) by converting the metal oxides or other compositions to chlorides in a molten salt, and subsequently using a combination of selective distillation at temperatures below about 500.degree. C., electrolysis at a voltage not more negative than about -1.5 volt versus Ag/AgCl, and precipitation to separate the desired manganese and cobalt salts from other metals and provide cobalt and manganese in metallic forms or compositions from which these metals may be more easily recovered.

Maroni, Victor A. (Naperville, IL); von Winbush, Samuel (Huntington, NY)

1988-01-01T23:59:59.000Z

102

Flexible metallic seal for transition duct in turbine system  

SciTech Connect (OSTI)

A turbine system is disclosed. In one embodiment, the turbine system includes a transition duct. The transition duct includes an inlet, an outlet, and a passage extending between the inlet and the outlet and defining a longitudinal axis, a radial axis, and a tangential axis. The outlet of the transition duct is offset from the inlet along the longitudinal axis and the tangential axis. The transition duct further includes an interface member for interfacing with a turbine section. The turbine system further includes a flexible metallic seal contacting the interface member to provide a seal between the interface member and the turbine section.

Flanagan, James Scott; LeBegue, Jeffrey Scott; McMahan, Kevin Weston; Dillard, Daniel Jackson; Pentecost, Ronnie Ray

2014-04-22T23:59:59.000Z

103

Tuning of the Metal-Insulator Transition via Alkali Adsorption  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Tuning of the Metal-Insulator Tuning of the Metal-Insulator Transition via Alkali Adsorption Tuning of the Metal-Insulator Transition via Alkali Adsorption Print Wednesday, 29 March 2006 00:00 Turning a material from an insulator to a metal, or vice versa, by light irradiation, exposure to electric or magnetic fields, or applying small changes in temperature, pressure, or doping-such intriguing control of a material's electronic properties is possible by exploiting strongly interacting or "correlated" electrons. Now a team of researchers from the University of Kiel in Germany and the ALS has found a novel, surprising way to continuously transform a layered metallic transition-metal compound, TaS2, into an insulator. Using angle-resolved photoemission spectroscopy (ARPES), they have demonstrated that adsorption of alkali atoms onto this material's surface gradually makes it more insulating, although in general, alkali adsorption should lead to more metallic behavior, as alkali atoms easily give away their loosely bound outermost electron.

104

Method and apparatus for the production of metal oxide powder  

DOE Patents [OSTI]

The present invention provides a method for preparing metal oxide powder. A first solution, which is substantially organic, is prepared. A second solution, which is an aqueous solution substantially immiscible in the first solution, is prepared and delivered as drops to the first solution. The drops of the second solution are atomized by a pulsed electric field forming micro-drops of the second solution. Reagents in the first solution diffuse into and react with reactants in the micro-drops of the second solution forming metal hydroxide or oxalate particles. The metal hydroxide or metal oxalate particles are then recovered and dried to produce the metal oxide powder. An apparatus for preparing a metal oxide powder is also disclosed.

Harris, Michael T. (Knoxville, TN); Scott, Timothy C. (Knoxville, TN); Byers, Charles H. (Oak Ridge, TN)

1993-01-01T23:59:59.000Z

105

Method and apparatus for the production of metal oxide powder  

DOE Patents [OSTI]

The present invention provides a method for preparing metal oxide powder. A first solution, which is substantially organic, is prepared. A second solution, which is an aqueous solution substantially immiscible in the first solution, is prepared and delivered as drops to the first solution. The drops of the second solution are atomized by a pulsed electric field forming micro-drops of the second solution. Reagents in the first solution diffuse into and react with reactants in the micro-drops of the second solution forming metal hydroxide or oxalate particles. The metal hydroxide or metal oxalate particles are then recovered and dried to produce the metal oxide powder. An apparatus for preparing a metal oxide powder is also disclosed.

Harris, Michael T. (Knoxville, TN); Scott, Timothy C. (Knoxville, TN); Byers, Charles H. (Oak Ridge, TN)

1992-01-01T23:59:59.000Z

106

Method and apparatus for the production of metal oxide powder  

DOE Patents [OSTI]

The present invention provides a method for preparing metal oxide powder. A first solution, which is substantially organic, is prepared. A second solution, which is an aqueous solution substantially immiscible in the first solution, is prepared and delivered as drops to the first solution. The drops of the second solution are atomized by a pulsed electric field forming micro-drops of the second solution. Reagents in the first solution diffuse into and react with reactants in the micro-drops of the second solution forming metal hydroxide or oxalate particles. The metal hydroxide or metal oxalate particles are then recovered and dried to produce the metal oxide powder. An apparatus for preparing a metal oxide powder is also disclosed. 2 figs.

Harris, M.T.; Scott, T.C.; Byers, C.H.

1992-06-16T23:59:59.000Z

107

Nanodisperse transition metal electrodes (NTME) for electrochemical cells  

DOE Patents [OSTI]

Disclosed are transition metal electrodes for electrochemical cells using gel-state and solid-state polymers. The electrodes are suitable for use in primary and secondary cells. The electrodes (either negative electrode or positive electrode) are characterized by uniform dispersion of the transition metal at the nanoscale in the polymer. The transition metal moiety is structurally amorphous, so no capacity fade should occur due to lattice expansion/contraction mechanisms. The small grain size, amorphous structure and homogeneous distribution provide improved charge/discharge cycling performance, and a higher initial discharge rate capability. The cells can be cycled at high current densities, limited only by the electrolyte conductivity. A method of making the electrodes (positive and negative), and their usage in electrochemical cells are disclosed.

Striebel, Kathryn A. (Oakland, CA); Wen, Shi-Jie (Sunnyvale, CA)

2000-01-01T23:59:59.000Z

108

Memristor using a transition metal nitride insulator  

DOE Patents [OSTI]

Apparatus is disclosed in which at least one resistive switching element is interposed between at least a first and a second conducting electrode element. The resistive switching element comprises a metal oxynitride. A method for making such a resistive switching element is also disclosed.

Stevens, James E; Marinella, Matthew; Lohn, Andrew John

2014-10-28T23:59:59.000Z

109

Metal-insulator transition in rare-gas-alkali-metal thin films  

Science Journals Connector (OSTI)

We report measurements of the conductivity and optical absorption in KrRb and XeCs thin films through the composition range spanning the metal-insulator transition. It is argued from chemical properties of the constituents that the conductivity loss must take the form of a percolative transition. In agreement with this assignment, the optical absorption shows no discontinuous or even marked change through the transitions. "Metallic" and "excitonic" features both persist on each side of the observed transitions in the two systems. The resistivity in metal-rich alloys yields residual resistivities for rare-gas impurities close to the values expected of vacancies, and the resistivity transitions at ? 75 at.% rare gas conform rather closely to the prediction of percolation theory.

D. J. Phelps and C. P. Flynn

1976-12-15T23:59:59.000Z

110

Method of physical vapor deposition of metal oxides on semiconductors  

DOE Patents [OSTI]

A process for growing a metal oxide thin film upon a semiconductor surface with a physical vapor deposition technique in a high-vacuum environment and a structure formed with the process involves the steps of heating the semiconductor surface and introducing hydrogen gas into the high-vacuum environment to develop conditions at the semiconductor surface which are favorable for growing the desired metal oxide upon the semiconductor surface yet is unfavorable for the formation of any native oxides upon the semiconductor. More specifically, the temperature of the semiconductor surface and the ratio of hydrogen partial pressure to water pressure within the vacuum environment are high enough to render the formation of native oxides on the semiconductor surface thermodynamically unstable yet are not so high that the formation of the desired metal oxide on the semiconductor surface is thermodynamically unstable. Having established these conditions, constituent atoms of the metal oxide to be deposited upon the semiconductor surface are directed toward the surface of the semiconductor by a physical vapor deposition technique so that the atoms come to rest upon the semiconductor surface as a thin film of metal oxide with no native oxide at the semiconductor surface/thin film interface. An example of a structure formed by this method includes an epitaxial thin film of (001)-oriented CeO.sub.2 overlying a substrate of (001) Ge.

Norton, David P. (Knoxville, TN)

2001-01-01T23:59:59.000Z

111

Plutonium metal and oxide container weld development and qualification  

SciTech Connect (OSTI)

Welds were qualified for a container system to be used for long-term storage of plutonium metal and oxide. Inner and outer containers are formed of standard tubing with stamped end pieces gas-tungsten-arc (GTA) welded onto both ends. The weld qualification identified GTA parameters to produce a robust weld that meets the requirements of the Department of Energy standard DOE-STD-3013-94, ``Criteria for the Safe Storage of Plutonium Metals and Oxides.``

Fernandez, R.; Horrell, D.R.; Hoth, C.W.; Pierce, S.W.; Rink, N.A.; Rivera, Y.M.; Sandoval, V.D.

1996-01-01T23:59:59.000Z

112

Inert electrode containing metal oxides, copper and noble metal  

DOE Patents [OSTI]

A cermet composite material is made by treating at an elevated temperature a mixture comprising a compound of iron and a compound of at least one other metal, together with an alloy or mixture of copper and a noble metal. The alloy or mixture preferably comprises particles having an interior portion containing more copper than noble metal and an exterior portion containing more noble metal than copper. The noble metal is preferably silver. The cermet composite material preferably includes alloy phase portions and a ceramic phase portion. At least part of the ceramic phase portion preferably has a spinel structure.

Ray, Siba P. (Murrysville, PA); Woods, Robert W. (New Kensington, PA); Dawless, Robert K. (Monroeville, PA); Hosler, Robert B. (Sarver, PA)

2001-01-01T23:59:59.000Z

113

Inert electrode containing metal oxides, copper and noble metal  

DOE Patents [OSTI]

A cermet composite material is made by treating at an elevated temperature a mixture comprising a compound of iron and a compound of at least one other metal, together with an alloy or mixture of copper and a noble metal. The alloy or mixture preferably comprises particles having an interior portion containing more copper than noble metal and an exterior portion containing more noble metal than copper. The noble metal is preferably silver. The cermet composite material preferably includes alloy phase portions and a ceramic phase portion. At least part of the ceramic phase portion preferably has a spinel structure.

Ray, Siba P. (Murrysville, PA); Woods, Robert W. (New Kensington, PA); Dawless, Robert K. (Monroeville, PA); Hosler, Robert B. (Sarver, PA)

2000-01-01T23:59:59.000Z

114

Electrophoretic-like Gating Used To Control Metal-Insulator Transitions in Electronically Phase Separated Manganite Wires  

E-Print Network [OSTI]

characteristics are shown to be fully reversible, polarity independent, and highly resistant to thermal breakdown, electrophoretic switching, transition metal oxides Resistive switching is observed across many different material, Elbio Dagotto,, Jian Shen,*,,# and T. Zac Ward*, Materials Science and Technology Division, Oak Ridge

Tennessee, University of

115

Hall effect at a tunable metal-insulator transition  

E-Print Network [OSTI]

Using a rotating magnetic field, the Hall effect in three-dimensional amorphous GdxSi1-x has been measured in the critical regime of the metal-insulator transition for a constant total magnetic field. The Hall coefficient R-0 is negative, indicating...

Teizer, Winfried; Hellman, F.; Dynes, RC.

2003-01-01T23:59:59.000Z

116

Insulator-metal transition on the triangular lattice  

Science Journals Connector (OSTI)

Mott insulators with a half-filled band of electrons on the triangular lattice have been recently studied in a variety of organic compounds. All of these compounds undergo transitions to metallic and/or superconducting states under moderate hydrostatic pressure. We describe the Mott insulator using its hypothetical proximity to a Z2 spin liquid of bosonic spinons. This spin liquid has quantum phase transitions to descendant confining states with Néel or valence bond solid order, and the insulator can be on either side of one of these transitions. We present a theory of fermionic charged excitations in these states and describe the route to metallic states with Fermi surfaces. We argue that an excitonic condensate can form near this insulator-metal transition due to the formation of charge neutral pairs of charge +e and charge ?e fermions. This condensate breaks the lattice space group symmetry, and we propose its onset as an explanation of a low temperature anomaly in ?-(ET)2Cu2(CN)3. We also describe the separate BCS instability of the metallic states to the pairing of like-charge fermions and the onset of superconductivity.

Yang Qi and Subir Sachdev

2008-04-09T23:59:59.000Z

117

Enhanced Half-Metallicity in Edge-Oxidized Zigzag Graphene  

E-Print Network [OSTI]

Enhanced Half-Metallicity in Edge-Oxidized Zigzag Graphene Nanoribbons Oded Hod,* Vero´nica Barone theoretical study of the electronic properties and relative stabilities of edge-oxidized zigzag graphene with nanometer scale dimen- sions. Recently, a new type of graphene-based material was experimentally realized.12

Hod, Oded

118

Metal-oxide-based energetic materials and synthesis thereof  

DOE Patents [OSTI]

A method of preparing energetic metal-oxide-based energetic materials using sol-gel chemistry has been invented. The wet chemical sol-gel processing provides an improvement in both safety and performance. Essentially, a metal-oxide oxidizer skeletal structure is prepared from hydrolyzable metals (metal salts or metal alkoxides) with fuel added to the sol prior to gelation or synthesized within the porosity metal-oxide gel matrix. With metal salt precursors a proton scavenger is used to destabilize the sol and induce gelation. With metal alkoxide precursors standard well-known sol-gel hydrolysis and condensation reactions are used. Drying is done by standard sol-gel practices, either by a slow evaporation of the liquid residing within the pores to produce a high density solid nanocomposite, or by supercritical extraction to produce a lower density, high porous nanocomposite. Other ingredients may be added to this basic nanostructure to change physical and chemical properties, which include organic constituents for binders or gas generators during reactions, burn rate modifiers, or spectral emitters.

Tillotson, Thomas M. (Tracy, CA), Simpson; Randall L. (Livermore, CA); Hrubesh, Lawrence W. (Pleasanton, CA)

2006-01-17T23:59:59.000Z

119

Comparative study of polyoxometalates and semiconductor metal oxides as catalyst. Photochemical oxidative degradation of thioethers  

SciTech Connect (OSTI)

The photochemical degradation of thioether substrates catalyzed by representative semiconductor metal oxides and sulfides (anatase TiO{sub 2}, SnO{sub 2}, cubic WO{sub 3}, and CdS) and photoredox-active early-transition-metal polyometalates (W{sub 10}O{sub 32}{sup 4{minus}}, PMo{sub 12}O{sub 40}{sup 3{minus}}, PW{sub 12}O{sub 40}{sup 3{minus}}, SiMo{sub 12}O{sub 40}{sup 4{minus}}, PV{sub 2}Mo{sub 10}O{sub 10}{sup 5{minus}}, and P{sub 2}W{sub 18}O{sub 62}{sup 6{minus}}) have been examined under both anaerobic and aerobic conditions. Under anaerobic conditions, all the semiconductors are completely ineffective at photochemically oxidizing or degrading the exemplary thioether substrate tetrahydrothiophene (THT) in the oxidatively resistant solvent acetonitrile. In contrast, all the homogeneous polyoxometalate systems under the same reaction condition, except the neutral tetra-n-butylammonium (Q) salt of PW{sub 12}O{sub 40}{sup 3{minus}}, are quite effective. The latter systems generate products derived from the carbon-based radical {alpha} to the sulfur atom and not sulfoxide or sulfone, the usual products of thioether oxidation by oxometal species. The rate for the most active anaerobic system, that involving the photochemical degradation of THT by Q{sub 4}W{sub 10}O{sub 32}, under optically dilute conditions, is first order in W{sub 10}O{sub 32} {sup 4{minus}} and light intensity and variable order in THT substrate. A rate law consistent with these data is given. Upon addition of O{sub 2}, TiO{sub 2} (with or without Pt(O)) becomes highly active, SnO{sub 2} becomes active, but WO{sub 3} and CdS remain inactive. Reactivity in thioether oxidation is dominated by the interactions of the semiconductors with O{sub 2} and O{sub 2}-derived intermediates; there is no correlation between reactivity and semiconductor band gap. Upon addition of O{sub 2}, all the polyoxometalate systems become more active. 29 refs., 4 figs., 3 tabs.

Chambers, R.C.; Hill, C.L. (Emory Univ., Atlanta, GA (United States))

1991-06-26T23:59:59.000Z

120

Aerosol chemical vapor deposition of metal oxide films  

DOE Patents [OSTI]

A process of preparing a film of a multicomponent metal oxide including: forming an aerosol from a solution comprised of a suitable solvent and at least two precursor compounds capable of volatilizing at temperatures lower than the decomposition temperature of said precursor compounds; passing said aerosol in combination with a suitable oxygen-containing carrier gas into a heated zone, said heated zone having a temperature sufficient to evaporate the solvent and volatilize said precursor compounds; and passing said volatilized precursor compounds against the surface of a substrate, said substrate having a sufficient temperature to decompose said volatilized precursor compounds whereby metal atoms contained within said volatilized precursor compounds are deposited as a metal oxide film upon the substrate is disclosed. In addition, a coated article comprising a multicomponent metal oxide film conforming to the surface of a substrate selected from the group consisting of silicon, magnesium oxide, yttrium-stabilized zirconium oxide, sapphire, or lanthanum gallate, said multicomponent metal oxide film characterized as having a substantially uniform thickness upon said substrate.

Ott, K.C.; Kodas, T.T.

1994-01-11T23:59:59.000Z

Note: This page contains sample records for the topic "transition metal oxide" 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.


121

Activation energy of hydrogen and muon in transition metals  

Science Journals Connector (OSTI)

The quantum theory of diffusion due to Flynn and Stoneham is used to calculate the activation energies of H, D, ?+, O, and N in bcc transition metals Nb, V, Ta, Mo, ?-W, and ?-Cr, and in fcc metals Pd, Ni, Cu, Ag, Au, and Al. It is found that the symmetric-mode contribution to the activation energy dominates in fcc metals while the reverse is the situation for bcc metals. The strain field produced by ?+ is found to be almost isotropic. The larger anisotropy and the volume of solution leads to large activation energy for heavy impurities. The calculated activation energies are found in good agreement with the experimental values. The variation of activation energy with the anisotropy parameter is also studied.

L. L. Dhawan and S. Prakash

1981-09-15T23:59:59.000Z

122

E-Print Network 3.0 - alb2-type transition-metal diborides Sample...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

alb2-type transition-metal diborides Search Powered by Explorit Topic List Advanced Search Sample search results for: alb2-type transition-metal diborides Page: << < 1 2 3 4 5 > >>...

123

E-Print Network 3.0 - adsorbate-modified transition metal Sample...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

adsorbate-modified transition metal Search Powered by Explorit Topic List Advanced Search Sample search results for: adsorbate-modified transition metal Page: << < 1 2 3 4 5 > >> 1...

124

E-Print Network 3.0 - acidic transition metals Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

liquids, chlorates, nitrites, sulfur, finely... hypochlorite, all oxidizing agents Carbon tetrachloride Sodium Chlorates Ammonium salts, acids, powdered metals... , copper,...

125

Metal-to-Semiconductor Transition in Hexagonal NiS  

Science Journals Connector (OSTI)

Recent electrical resistivity measurements have shown that the hexagonal form of stoichiometric NiS exhibits an abrupt metal-to-semiconductor transition at 264°K. Neutron diffraction studies have shown that a first-order paramagnetic-to-antiferromagnetic transition also occurs at 264°K. No crystal lattice distortion is observed at the transition nor detected at 4.2°K, suggesting that this may be a transition of the kind considered by Adler and Brooks. The measured magnetic moment at 4.2°K is 1.66±0.08 ?? and at 260°K it is 150.±0.10 ?? indicating that the sublattice magnetization is within 10% of saturation immediately upon ordering. The neutron data also shown that no more than about 1% of the Ni atoms migrate to tetragonal interstitial sites on warming from 4.2°K to room temperature. Thus, Ni atom migration apparently plays no part in this transition. The powder magnetic susceptibility is 2.24×10-6 emu/g at 300°K and is virtually temperature-independent above the transition. ? increases abruptly at 264°K by about 15% and exhibits some field-cooling effects. Studies on the compounds NiXS, for X=1.01, 0.99, 0.97, and 0.94 show that excess sulfur lowers the transition temperature.

JOSEPH T. SPARKS and TED KOMOTO

1968-10-01T23:59:59.000Z

126

Promises and Challenges of Lithium- and Manganese-Rich Transition...  

Broader source: Energy.gov (indexed) [DOE]

Promises and Challenges of Lithium- and Manganese-Rich Transition-Metal Layered-Oxide Cathodes Promises and Challenges of Lithium- and Manganese-Rich Transition-Metal Layered-Oxide...

127

Holographic Polarons, the Metal-Insulator Transition and Massive Gravity  

E-Print Network [OSTI]

Massive gravity is holographically dual to `realistic' materials with momentum relaxation. The dual graviton potential encodes the phonon dynamics and it allows for a much broader diversity than considered so far. We construct a simple family of isotropic and homogeneous materials that exhibit an interaction-driven Metal-Insulator transition. The transition is triggered by the formation of polarons -- phonon-electron quasi-bound states that dominate the conductivities, shifting the spectral weight above a mass gap. We characterize the polaron gap, width and dispersion.

Baggioli, Matteo

2014-01-01T23:59:59.000Z

128

Holographic Polarons, the Metal-Insulator Transition and Massive Gravity  

E-Print Network [OSTI]

Massive gravity is holographically dual to `realistic' materials with momentum relaxation. The dual graviton potential encodes the phonon dynamics and it allows for a much broader diversity than considered so far. We construct a simple family of isotropic and homogeneous materials that exhibit an interaction-driven Metal-Insulator transition. The transition is triggered by the formation of polarons -- phonon-electron quasi-bound states that dominate the conductivities, shifting the spectral weight above a mass gap. We characterize the polaron gap, width and dispersion.

Matteo Baggioli; Oriol Pujolas

2014-11-04T23:59:59.000Z

129

Vacancy Hardening and Softening in Transition Metal Carbides and Nitrides  

SciTech Connect (OSTI)

The effects of vacancies on mechanical properties of the transition metal carbides and nitrides are studied using the ab initio pseudopotential approach. Calculated shear elastic stiffness and electronic structures show that the vacancy produces entirely different effects on the mechanical strength of groups IVb nitrides and Vb carbides. It is found that the occupation of shear-unstable metallic dd bonding states changes essentially in an opposite way for the carbides and nitrides in the presence of vacancies, resulting in different responses to shear stress. Our study provides an atomistic understanding of the anomaly in hardness for these substoichiometric materials.

Jhi, Seung-Hoon; Louie, Steven G.; Cohen, Marvin L.; Ihm, Jisoon

2001-04-09T23:59:59.000Z

130

X-ray Absorption Spectroscopy of Transition Metal-Magnesium Hydride Thin Films  

E-Print Network [OSTI]

X-ray Absorption Spectroscopy of Transition Metal-Magnesium Hydride Thin Films T. J. Richardsona@lbl.gov Abstract Mixed metal thin films containing magnesium and a first-row transition element exhibit very large and coordination of the magnesium and transition metal atoms during hydrogen absorption were studied using dynamic

131

Electronic structure and pairwise interactions in substoichiometric transition metal carbides and nitrides  

E-Print Network [OSTI]

1001 Electronic structure and pairwise interactions in substoichiometric transition metal carbides observations expéri- mentales. Abstract 2014 In substoichiometric transition metal carbides and nitrides This paper is devoted to the study of the ordering processes in substoichiometric transition metal carbi- des

Paris-Sud XI, Université de

132

Trends in elasticity and electronic structure of transition-metal nitrides and carbides from first principles  

E-Print Network [OSTI]

Trends in elasticity and electronic structure of transition-metal nitrides and carbides from first 2005 The elastic properties of selected transition-metal TM nitrides and carbides in B1 structure the transition-metal nitrides and carbides remain unclear and a challenge for engineering hard materials

Wu, Zhigang

133

Metallic Materials in Solid Oxide Fuel Cells  

Science Journals Connector (OSTI)

Fe-Cr alloys with variations in chromium content and additions of different elements were studied for potential application in intermediate temperature Solid Oxide Fuel Cell (SOFC). Recently, a new type of FeC...

V. Shemet; J. Piron-Abellan; W.J. Quadakkers…

2005-01-01T23:59:59.000Z

134

Investigation of methods for the selective removal and characterization of transition metals associated with solids in the marine environment  

SciTech Connect (OSTI)

The operation of an OTEC plant will result in the mixing of large volumes of seawater from different depths within the ocean. Because suspended particulate material is intimately involved in marine food webs and transition metals, such as copper, can have toxic effects, it is important to develop a sound methodology for characterizing and quantifying transition metal behavior associated with the solid material. The characterization of solid-phase-associated transition metals in the marine environment has largely been directed at marine sediments. These studies have generally indicated that it is not possible to uniquely identify the solid phases or chemical speciation of a given metal. There are many reasons for this difficulty, but the probable major analytical problems arise from the fact that many of the transition metals of interest are present only in trace concentrations as adsorbed species on amorphous oxides or as coprecipitates. In one approach transition metals are classified according to how easily they are solubilized when exposed to different types of chemical attack, as defined in chemical extraction schemes. In this study, several of the most widely accepted extraction techniques were compared for many of the most commonly measured transition metals to a variety of marine sediments. Based on the results of this study, the sequential extraction scheme of Tessler et al. (1979) is the recommended method for the characterization of solid-phase associated transition metals. An increase of the reducing agent concentration in the intermediate step and temperature decrease with an additional HCl digestion in the residual step are recommended as improvements, based on the results of the individual extraction method studies.

Van Valin, R.; Morse, J.W.

1981-02-01T23:59:59.000Z

135

Zwitterionic Group VIII transition metal initiators supported by olefin ligands  

DOE Patents [OSTI]

A zwitterionic Group VIII transition metal complex containing the simple and relatively small 3-(arylimino)-but-1-en-2-olato ligand that catalyzes the formation of polypropylene and high molecular weight polyethylene. A novel feature of this catalyst is that the active species is stabilized by a chelated olefin adduct. The present invention also provides methods of polymerizing olefin monomers using zwitterionic catalysts, particularly polypropylene and high molecular weight polyethylene.

Bazan, Guillermo C. (Goleta, CA); Chen, Yaofeng (Shanghai, CN)

2011-10-25T23:59:59.000Z

136

Energy conversion catalysis using semiconducting transition metal cluster compounds  

Science Journals Connector (OSTI)

... semiconducting materials that provide a high density of transition metal d-states bordering the forbidden energy region (d-band semiconductors). During a detailed study of RuS2, the best material ... for photo-induced evolution of oxygen3, it became apparent that ~0.5 eV of energy per transferred electron is lost in the course of trapping positive charge carriers in the ...

N. Alonso Vante; H. Tributsch

1986-10-02T23:59:59.000Z

137

Catalytic Graphitization of Carbon Aerogels by Transition Metals  

Science Journals Connector (OSTI)

Catalytic Graphitization of Carbon Aerogels by Transition Metals ... Carbon aerogels and Cr-, Fe-, Co-, and Ni-containing carbon aerogels were obtained by pyrolysis, at temperatures between 500 and 1800 °C, of the corresponding aerogels prepared by the sol?gel method from polymerization of resorcinol with formaldehyde. ... Results obtained show that carbon aerogels are, essentially, macroporous materials that maintain large pore volumes even after pyrolysis at 1800 °C. ...

F. J. Maldonado-Hódar; C. Moreno-Castilla; J. Rivera-Utrilla; Y. Hanzawa; Y. Yamada

2000-03-24T23:59:59.000Z

138

Flame Synthesis of One-Dimensional Metal Oxide Nanomaterials  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Synthesis of One-Dimensional Metal Oxide Nanomaterials Synthesis of One-Dimensional Metal Oxide Nanomaterials Alexei V. Saveliev Dept. of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC 27695, USA Robust, scalable, and energy efficient methods of nanomaterial synthesis are needed to meet the demands of current and potential applications. Flames have been successfully applied for the synthesis of metal oxide and ceramic nanopowders largely composed of spherical particles and their aggregates. In recent years, premixed and diffusion flames have been employed for the synthesis of 1-D carbon nanoforms such as carbon fibers and carbon nanotubes. The extension of flame methods to gas phase and solid support synthesis of 1-D inorganic nanoforms is of great interest and significance. This talk presents

139

Transition-metal doped sulfide, selenide, and telluride laser crystal and lasers  

DOE Patents [OSTI]

A new class of solid state laser crystals and lasers are formed of transition metal doped sulfide, selenide, and telluride host crystals which have four fold coordinated substitutional sites. The host crystals include II-VI compounds. The host crystal is doped with a transition metal laser ion, e.g., chromium, cobalt or iron. In particular, Cr{sup 2+}-doped ZnS and ZnSe generate laser action near 2.3 {micro}m. Oxide, chloride, fluoride, bromide and iodide crystals with similar structures can also be used. Important aspects of these laser materials are the tetrahedral site symmetry of the host crystal, low excited state absorption losses and high luminescence efficiency, and the d{sup 4} and d{sup 6} electronic configurations of the transition metal ions. The same materials are also useful as saturable absorbers for passive Q-switching applications. The laser materials can be used as gain media in amplifiers and oscillators; these gain media can be incorporated into waveguides and semiconductor lasers. 18 figs.

Krupke, W.F.; Page, R.H.; DeLoach, L.D.; Payne, S.A.

1996-07-30T23:59:59.000Z

140

Metal current collect protected by oxide film  

DOE Patents [OSTI]

Provided are low-cost, mechanically strong, highly electronically conductive current collects and associated structures for solid-state electrochemical devices, techniques for forming these structures, and devices incorporating the structures. The invention provides solid state electrochemical devices having as current interconnects a ferritic steel felt or screen coated with a protective oxide film.

Jacobson, Craig P. (Lafayette, CA); Visco, Steven J. (Berkeley, CA); DeJonghe, Lutgard C. (Lafayette, CA)

2004-05-25T23:59:59.000Z

Note: This page contains sample records for the topic "transition metal oxide" 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

Amorphous semiconducting and conducting transparent metal oxide thin films and production thereof  

DOE Patents [OSTI]

Metal oxide thin films and production thereof are disclosed. An exemplary method of producing a metal oxide thin film may comprise introducing at least two metallic elements and oxygen into a process chamber to form a metal oxide. The method may also comprise depositing the metal oxide on a substrate in the process chamber. The method may also comprise simultaneously controlling a ratio of the at least two metallic elements and a stoichiometry of the oxygen during deposition. Exemplary amorphous metal oxide thin films produced according to the methods herein may exhibit highly transparent properties, highly conductive properties, and/or other opto-electronic properties.

Perkins, John (Boulder, CO); Van Hest, Marinus Franciscus Antonius Maria (Lakewood, CO); Ginley, David (Evergreen, CO); Taylor, Matthew (Golden, CO); Neuman, George A. (Holland, MI); Luten, Henry A. (Holland, MI); Forgette, Jeffrey A. (Hudsonville, MI); Anderson, John S. (Holland, MI)

2010-07-13T23:59:59.000Z

142

Design Principles for Oxygen-Reduction Activity on Perovskite Oxide Catalysts for Fuel Cells and Metal-air Batteries  

SciTech Connect (OSTI)

The prohibitive cost and scarcity of the noble-metal catalysts needed for catalysing the oxygen reduction reaction (ORR) in fuel cells and metal-air batteries limit the commercialization of these clean-energy technologies. Identifying a catalyst design principle that links material properties to the catalytic activity can accelerate the search for highly active and abundant transition-metal-oxide catalysts to replace platinum. Here, we demonstrate that the ORR activity for oxide catalysts primarily correlates to {sigma}*-orbital (e{sub g}) occupation and the extent of B-site transition-metal-oxygen covalency, which serves as a secondary activity descriptor. Our findings reflect the critical influences of the {sigma}* orbital and metal-oxygen covalency on the competition between O{sub 2}{sup 2-}/OH{sup -} displacement and OH{sup -} regeneration on surface transition-metal ions as the rate-limiting steps of the ORR, and thus highlight the importance of electronic structure in controlling oxide catalytic activity.

J Suntivich; H Gasteiger; N Yabuuchi; H Nakanishi; J Goodenough; Y Shao-Horn

2011-12-31T23:59:59.000Z

143

Nonprecious Metal Catalysts for Low Temperature Solid Oxide Fuel Cells  

Science Journals Connector (OSTI)

Nonprecious Metal Catalysts for Low Temperature Solid Oxide Fuel Cells ... Initial and final state geometries are found with standard geometry optimization, then a number of intermediate states are generated by interpolation of atomic positions. ... A special "metric" and a special "preconditioning" optimized for a plane-wave basis set will be introduced. ...

Timothy P. Holme; Fritz B. Prinz

2011-05-24T23:59:59.000Z

144

245H. Dreysse et al.: Calculation of Interactions Between Adsorbates on Transition Metal Surfaces Calculation of Interactions Between Adsorbates on Transition Metal Surfaces  

E-Print Network [OSTI]

245H. Dreysse et al.: Calculation of Interactions Between Adsorbates on Transition Metal Surfaces ------------- Calculation of Interactions Between Adsorbates on Transition Metal Surfaces H. Dreysse*), D. Tomanek, and K. H the interaction W n (i) between n adsorbed atoms of type A in a geometrical arrangement i (given

145

Low-temperature oriented growth of vanadium dioxide films on CoCrTa metal template on Si and vertical metal-insulator transition  

SciTech Connect (OSTI)

The authors achieved oriented growth of vanadium dioxide (VO{sub 2}) films on CoCrTa metal template grown on an Si substrate. Low-temperature ({approx}250 Degree-Sign C) deposition of VO{sub 2} films using inductively coupled-plasma-assisted sputtering technique realized an abrupt interface between VO{sub 2} and CoCrTa layers, suppressing the oxidation and diffusion of metal components. The films revealed a metal-insulator transition with resistance change of over 2 orders of magnitude. The CoCrTa film, in which Co hexagonal crystalline grains with c-axis orientation were surrounded by segregated Cr and Ta, serves for the oriented growth of VO{sub 2} crystalline film, enabling higher orders of transition in resistance and low voltage switching, even for the vertical (out-of-plane) direction.

Okimura, Kunio; Mian, Md.Suruz [School of Engineering, Tokai University, 4-1-1 Kitakaname, Hiratsuka, Kanagawa 259-1292 (Japan)

2012-09-15T23:59:59.000Z

146

Metal Oxide Nanoparticles as Bactericidal Agents  

Science Journals Connector (OSTI)

8 Magnesium oxide prepared through an aerogel procedure (AP-MgO)9 yields square and polyhedral shaped nanoparticles with diameters varying slightly around 4 nm, arranged in an extensive porous structure with considerable pore volume. ... Approximately 106 CFU (colony forming units) of bacteria or spores were deposited on water filtration membranes with pore size 0.45 ?m (Millipore Corp.). ... The filters were dried at ambient conditions for 30 min and then completely covered with 0.25 g of AP-MgO/X2 (X = Cl, Br, none). ...

Peter K. Stoimenov; Rosalyn L. Klinger; George L. Marchin; Kenneth J. Klabunde

2002-07-04T23:59:59.000Z

147

Reduction of Metal Oxides by Microwave Heating of Multi-walled...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Reduction of Metal Oxides by Microwave Heating of Multi-walled Carbon Nanotubes Microwave heating of a metal oxide in the presence of multi-walled carbon nanotubes may result in...

148

Electrical excitation of colloidally synthesized quantum dots in metal oxide structures  

E-Print Network [OSTI]

This thesis develops methods for integrating colloidally synthesized quantum dots (QDs) and metal oxides in optoelectronic devices, presents three distinct light emitting devices (LEDs) with metal oxides surrounding a QD ...

Wood, Vanessa Claire

2010-01-01T23:59:59.000Z

149

Metal-insulator Transition by Holographic Charge Density Waves  

E-Print Network [OSTI]

We construct a gravity dual for charge density waves (CDW) in which the translational symmetry along one spatial direction is spontaneously broken. Our linear perturbation calculation on the gravity side produces the frequency dependence of the optical conductivity, which exhibits the two familiar features of charge density waves, namely the pinned collective mode and gapped single-particle excitation. These two features indicate that our gravity dual also provides a new mechanism to implement the metal to insulator phase transition by CDW, which is further supported by the fact that d.c. conductivity decreases with the decreased temperature below the critical temperature.

Yi Ling; Chao Niu; Jianpin Wu; Zhuoyu Xian; Hongbao Zhang

2014-04-03T23:59:59.000Z

150

Rare earth-transition metal scrap treatment method  

DOE Patents [OSTI]

Rare earth-transition metal (e.g. iron) scrap (e.g. Nd-Fe-B scrap) is melted to reduce the levels of tramp oxygen and nitrogen impurities therein. The tramp impurities are reduced in the melt by virtue of the reaction of the tramp impurities and the rare earth to form dross on the melt. The purified melt is separated from the dross for reuse. The oxygen and nitrogen of the melt are reduced to levels acceptable for reuse of the treated alloy in the manufacture of end-use articles, such as permanent magnets. 3 figs.

Schmidt, F.A.; Peterson, D.T.; Wheelock, J.T.; Jones, L.L.; Lincoln, L.P.

1992-02-11T23:59:59.000Z

151

Cross-plane thermal properties of transition metal dichalcogenides  

SciTech Connect (OSTI)

In this work, we explore the thermal properties of hexagonal transition metal dichalcogenide compounds with different average atomic masses but equivalent microstructures. Thermal conductivity values of sputtered thin films were compared to bulk crystals. The comparison revealed a >10 fold reduction in thin film thermal conductivity. Structural analysis of the films revealed a turbostratic structure with domain sizes on the order of 5-10 nm. Estimates of phonon scattering lengths at domain boundaries based on computationally derived group velocities were consistent with the observed film microstructure, and accounted for the reduction in thermal conductivity compared to values for bulk crystals.

Muratore, C. [Department of Chemical and Materials Engineering, University of Dayton, Dayton, Ohio 45469 (United States) [Department of Chemical and Materials Engineering, University of Dayton, Dayton, Ohio 45469 (United States); Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright-Patterson AFB, Ohio 45433 (United States); Varshney, V. [Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright-Patterson AFB, Ohio 45433 (United States) [Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright-Patterson AFB, Ohio 45433 (United States); Universal Technology Corporation, Dayton, Ohio 45432 (United States); Gengler, J. J. [Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright-Patterson AFB, Ohio 45433 (United States) [Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright-Patterson AFB, Ohio 45433 (United States); Spectral Energies LLC, Dayton, Ohio 45431 (United States); Hu, J. J.; Bultman, J. E. [Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright-Patterson AFB, Ohio 45433 (United States) [Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright-Patterson AFB, Ohio 45433 (United States); University of Dayton Research Institute, Dayton, Ohio 45469 (United States); Smith, T. M. [Department of Materials Science and Engineering, Ohio State University, Columbus, Ohio 43210 (United States)] [Department of Materials Science and Engineering, Ohio State University, Columbus, Ohio 43210 (United States); Shamberger, P. J.; Roy, A. K.; Voevodin, A. A. [Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright-Patterson AFB, Ohio 45433 (United States)] [Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright-Patterson AFB, Ohio 45433 (United States); Qiu, B.; Ruan, X. [Department of Mechanical Engineering and Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907 (United States)] [Department of Mechanical Engineering and Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907 (United States)

2013-02-25T23:59:59.000Z

152

Incompressibility and Hardness of Solid Solution Transition Metal Diborides: Os1-xRuxB2  

E-Print Network [OSTI]

cannot be used to cut steel or other ferrous metals because of the formation of iron carbide at elevatedIncompressibility and Hardness of Solid Solution Transition Metal Diborides: Os1-xRuxB2 Michelle B materials has prompted studies of transition metal diboride solid solutions. We have synthesized pure RuB2

Tolbert, Sarah

153

Transition-metal silicides as materials for magnet-semiconductor heterostructures*  

E-Print Network [OSTI]

Transition-metal silicides as materials for magnet-semiconductor heterostructures* Peter Kratzer as of binary late transition metal monosilicides, in contact with the Si surface. For the Heusler alloy Co2MnSi, we could show that the 001 surface retains the half-metallic character of the bulk if a fully Mn

154

Cyclic catalytic upgrading of chemical species using metal oxide materials  

DOE Patents [OSTI]

Processes are disclosure which comprise alternately contacting an oxygen-carrying catalyst with a reducing substance, or a lower partial pressure of an oxidizing gas, and then with the oxidizing gas or a higher partial pressure of the oxidizing gas, whereby the catalyst is alternately reduced and then regenerated to an oxygenated state. In certain embodiments, the oxygen-carrying catalyst comprises at least one metal oxide-containing material containing a composition having the following formulas: (a) Ce.sub.xB.sub.yB'.sub.zB''O.sub..delta., wherein B=Ba, Sr, Ca, or Zr; B'=Mn, Co, and/or Fe; B''=Cu; 0.01metal oxides.

White, James H; Schutte, Erick J; Rolfe, Sara L

2013-05-07T23:59:59.000Z

155

Influence of uranium hydride oxidation on uranium metal behaviour  

SciTech Connect (OSTI)

This work addresses concerns that the rapid, exothermic oxidation of active uranium hydride in air could stimulate an exothermic reaction (burning) involving any adjacent uranium metal, so as to increase the potential hazard arising from a hydride reaction. The effect of the thermal reaction of active uranium hydride, especially in contact with uranium metal, does not increase in proportion with hydride mass, particularly when considering large quantities of hydride. Whether uranium metal continues to burn in the long term is a function of the uranium metal and its surroundings. The source of the initial heat input to the uranium, if sufficient to cause ignition, is not important. Sustained burning of uranium requires the rate of heat generation to be sufficient to offset the total rate of heat loss so as to maintain an elevated temperature. For dense uranium, this is very difficult to achieve in naturally occurring circumstances. Areas of the uranium surface can lose heat but not generate heat. Heat can be lost by conduction, through contact with other materials, and by convection and radiation, e.g. from areas where the uranium surface is covered with a layer of oxidised material, such as burned-out hydride or from fuel cladding. These rates of heat loss are highly significant in relation to the rate of heat generation by sustained oxidation of uranium in air. Finite volume modelling has been used to examine the behaviour of a magnesium-clad uranium metal fuel element within a bottle surrounded by other un-bottled fuel elements. In the event that the bottle is breached, suddenly, in air, it can be concluded that the bulk uranium metal oxidation reaction will not reach a self-sustaining level and the mass of uranium oxidised will likely to be small in relation to mass of uranium hydride oxidised. (authors)

Patel, N.; Hambley, D. [National Nuclear Laboratory (United Kingdom); Clarke, S.A. [Sellafield Ltd (United Kingdom); Simpson, K.

2013-07-01T23:59:59.000Z

156

Preparation and evaluation of novel hydrous metal oxide (HMO)-supported noble metal catalysts  

SciTech Connect (OSTI)

Hydrous Metal Oxides (HMOs) are chemically synthesized materials that, because of their high cation exchange capacity, possess a unique ability to allow the preparation of highly dispersed supported-metal catalyst precursors with high metal loadings. This study evaluates high weight loading Rh/HMO catalysts with a wide range of HMO support compositions, including hydrous titanium oxide (HTO), silica-doped hydrous titanium oxide (HTO:Si), hydrous zirconium oxide (HZO), and silica-doped hydrous zirconium oxide (HZO:Si), against conventional oxide-supported Rh catalysts with similar weight loadings and support chemistries. Catalyst activity measurements for a structure-sensitive model reaction (n-butane hydrogenolysis) as a function of catalyst activation conditions show superior activity and stability for the ZrO{sub 2}, HZO, and HZO:Si supports, although all of the Rh/HMO catalysts have high ethane selectivity indicative of high Rh dispersion. For the TiO{sub 2}-, HTO-, and HTO:Si supported Rh catalysts, a significant loss of both catalyst activity and Rh dispersion is observed at more aggressive activation conditions, consistent with TiO{sub x} migration associated with SMSI phenomena. Of all the Rh/HMO catalysts, the Rh/HZO:Si catalysts appear to offer the best tradeoff in terms of high Rh dispersion, high activity, and high selectivity.

Gardner, T.J.; McLaughlin, L.I.; Evans, L.R. [Sandia National Labs., Albuquerque, NM (United States). Catalysis and Chemical Technologies Dept.; Datye, A.K. [Univ. of New Mexico, Albuquerque, NM (United States)

1998-04-01T23:59:59.000Z

157

Reactions of S-nitrosothiols with biomimetic iron complexes and other transition metals  

E-Print Network [OSTI]

Chapter 1. Bioinorganic Chemistry of Nitric Oxide and S-Nitrosothiols The interplay of nitric oxide (NO), biological thiols, and metals has been a topic of intense study since the discovery of NO as the endothelium-derived ...

Victor, Eric, Ph. D. Massachusetts Institute of Technology

2014-01-01T23:59:59.000Z

158

Metal-insulator transition in expanded alkali-metal fluids and alkali-metal—rare-gas films  

Science Journals Connector (OSTI)

We have developed a theoretical model for expanded alkali metals and alkali-metal—rare-gas films that is based on a physically realistic picture of the atomic-scale structure of these materials. It emphasizes the disorder in the systems, in particular the random atomic coordination number. Using this model we have calculated the density- and the energy-dependent conductivity as a function of the mean alkali-metal atomic coordination number. Although the theory contains only two parameters, both of which are fixed by the properties of pure materials at normal temperatures, we have been able to explain results measured over a temprature range from 4.2 to >2000 K in a variety of different alkali-metal systems. Conductivity and magnetic-susceptibility measurements, in particular, have been considered in some detail. In addition, the theory provides insight into the nature and location of the metal-insulator transition, the nature of the critical point for the alkali metals, and the thermal instability of the alkali-metal—rare-gas films.

Judy R. Franz

1984-02-15T23:59:59.000Z

159

ARC DISCHARGE SYNTHESIS AND MORPHOLOGY CONTROL OF EARLY TRANSITION METAL CARBIDE NANOPATICLES.  

E-Print Network [OSTI]

??This work is directed to the understanding of the synthesis and morphology control of early transition metal carbides. Chapter 1 gives an introduction to fcc… (more)

Grove , David

2010-01-01T23:59:59.000Z

160

Transition metal interaction and Ni-Fe-Cu-Si phases in silicon T. Buonassisi,b  

E-Print Network [OSTI]

precipitation may reduce the lattice mismatch compared to single-metal precipitates, rendering mixed-metal-silicide recombination activity of metal silicide clusters. Common solar cell materials are not contaminated with justTransition metal interaction and Ni-Fe-Cu-Si phases in silicon M. Heuer,a T. Buonassisi,b A. A

Note: This page contains sample records for the topic "transition metal oxide" 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

Strengthening of metallic alloys with nanometer-size oxide dispersions  

DOE Patents [OSTI]

Austenitic stainless steels and nickel-base alloys containing, by wt. %, 0.1 to 3.0% V, 0.01 to 0.08% C, 0.01 to 0.5% N, 0.05% max. each of Al and Ti, and 0.005 to 0.10% O, are strengthened and ductility retained by atomization of a metal melt under cover of an inert gas with added oxygen to form approximately 8 nanometer-size hollow oxides within the alloy grains and, when the alloy is aged, strengthened by precipitation of carbides and nitrides nucleated by the hollow oxides. Added strengthening is achieved by nitrogen solid solution strengthening and by the effect of solid oxides precipitated along and pinning grain boundaries to provide temperature-stabilization and refinement of the alloy grains.

Flinn, John E. (Idaho Falls, ID); Kelly, Thomas F. (Madison, WI)

1999-01-01T23:59:59.000Z

162

Strengthening of metallic alloys with nanometer-size oxide dispersions  

DOE Patents [OSTI]

Austenitic stainless steels and nickel-base alloys containing, by wt. %, 0.1 to 3.0% V, 0.01 to 0.08% C, 0.01 to 0.5% N, 0.05% max. each of Al and Ti, and 0.005 to 0.10% O, are strengthened and ductility retained by atomization of a metal melt under cover of an inert gas with added oxygen to form approximately 8 nanometer-size hollow oxides within the alloy grains and, when the alloy is aged, strengthened by precipitation of carbides and nitrides nucleated by the hollow oxides. Added strengthening is achieved by nitrogen solid solution strengthening and by the effect of solid oxides precipitated along and pinning grain boundaries to provide temperature-stabilization and refinement of the alloy grains. 20 figs.

Flinn, J.E.; Kelly, T.F.

1999-06-01T23:59:59.000Z

163

Lithium Metal Oxide Electrodes For Lithium Cells And Batteries  

DOE Patents [OSTI]

A lithium metal oxide positive electrode for a non-aqueous lithium cell is disclosed. The cell is prepared in its initial discharged state and has a general formula xLiMO.sub.2.(1-x)Li.sub.2 M'O.sub.3 in which 0oxidation state and with at least one ion being Mn or Ni, and where M' is one or more ion with an average tetravalent oxidation state. Complete cells or batteries are disclosed with anode, cathode and electrolyte as are batteries of several cells connected in parallel or series or both.

Thackeray, Michael M. (Naperville, IL); Johnson, Christopher S. (Naperville, IL); Amine, Khalil (Downers Grove, IL); Kim, Jaekook (Naperville, IL)

2004-01-20T23:59:59.000Z

164

Lithium metal oxide electrodes for lithium cells and batteries  

DOE Patents [OSTI]

A lithium metal oxide positive electrode for a non-aqueous lithium cell is disclosed. The cell is prepared in its initial discharged state and has a general formula xLiMO.sub.2.(1-x)Li.sub.2M'O.sub.3 in which 0oxidation state and with at least one ion being Mn or Ni, and where M' is one or more ion with an average tetravalent oxidation state. Complete cells or batteries are disclosed with anode, cathode and electrolyte as are batteries of several cells connected in parallel or series or both.

Thackeray, Michael M. (Naperville, IL); Johnson, Christopher S. (Naperville, IL); Amine, Khalil (Oakbrook, IL)

2008-12-23T23:59:59.000Z

165

The Role of Carbon in Catalytically Stabilized Transition Metal Sulfides  

SciTech Connect (OSTI)

Since WWII considerable progress has been made in understanding the basis for the activity and the selectivity of molybdenum and tungsten based hydrotreating catalysts. Recently, the focus of investigation has turned to the structure of the catalytically stabilized active catalyst. The surface of the catalytically stabilized MoS2 has been shown to be carbided with the formula MoSxCy under hydrotreating conditions. In this paper we review the basis for this finding and present new data extending the concept to the promoted TMS (transition metal sulfides) systems CoMoC and NiMoC. Freshly sulfided CoMoS and NiMoS catalyst have a strong tendency to form the carbided surface phases from any available carbon source.

Kelty,S.; Berhault, G.; Chianelli, R.

2007-01-01T23:59:59.000Z

166

Alkali monolayers on transition metal surfaces: electronic promotion in catalysis  

SciTech Connect (OSTI)

Potassium monolayers on the platinum (111) crystal surface were studied most extensively. Ultraviolet photoelectron spectroscopy showed a large decrease in the work function of the surface when potassium was adsorbed. The heat of desorption of potassium decreased with increasing coverage. Low energy electron diffraction (LEED) showed that potassium forms hexagonal (close packed) overlayer structures. The effects of potassium on the chemisorption of various small molecules on Pt(111) were studied. Oxygen and nitric oxide were readily adsorbed and dissociated by potassium, forming stable potassium-oxide complexes on the surface. Adsorption heat of carbon monoxide on Pt(111) increased with potassium coadsorption. High resolution electron energy loss spectroscopy showed that the carbon-oxygen bond of adsorbed carbon monoxide was weakened by potassium. Adsorption heat of benzene, however, was decreased by coadsorbed potassium. A molecular orbital explanation was given to explain the effects of potassium. CO hydrogenation reactions performed on metal foils showed that the addition of alkali adlayers tends to decrease the overall rate of reaction. Changes in selectivity were noted, shifting the product distribution in favor of higher molecular weight species and from alkanes to alkenes.

Garfunkel, E.

1983-08-01T23:59:59.000Z

167

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

Science Journals Connector (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 critical components of low and zero emission vehicles produce much higher levels of engine-out NO x and current three-way catalytic converters are not sufficient to meet Clean Air Act standards. Platinum catalysts were formed by the reaction of modified Pt coordination compounds with selected transition–metal alkoxides through sol–gel techniques into aerogels. Photoemission measurements of the Pt 4f Si 2p Ti 2p O 1s and C 1s core lines were used to evaluate the chemistry of the material after each processing step. Results indicate Pt–O bonding and reduced Pt disbursed in the aerogel. In addition Si 2p Ti 2p and O 1s binding energies indicate an oxo-bridged network structure.

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

2001-01-01T23:59:59.000Z

168

Multilayered thermal insulation formed of zirconia bonded layers of zirconia fibers and metal oxide fibers and method for making same  

DOE Patents [OSTI]

A multilayered thermal insulating composite is formed of a first layer of zirconia-bonded zirconia fibers for utilization near the hot phase or surface of a furnace or the like. A second layer of zirconia-bonded metal oxide fibers is attached to the zirconia fiber layer by a transition layer formed of intermingled zirconia fibers and metal oxide fibers. The thermal insulation is fabricated by vacuum molding with the layers being sequentially applied from aqueous solutions containing the fibers to a configured mandrel. A portion of the solution containing the fibers forming the first layer is intermixed with the solution containing the fibers of the second layer for forming the layer of mixed fibers. The two layers of fibers joined together by the transition layer are saturated with a solution of zirconium oxynitrate which provides a zirconia matrix for the composite when the fibers are sintered together at their nexi.

Wrenn, Jr., George E. (Clinton, TN); Holcombe, Jr., Cressie E. (Farragut, TN)

1988-01-01T23:59:59.000Z

169

Magnetic preferential orientation of metal oxide superconducting materials  

DOE Patents [OSTI]

A superconductor comprised of a polycrystalline metal oxide such as YBa[sub 2]Cu[sub 3]O[sub 7[minus]X] (where 0 < X < 0.5) exhibits superconducting properties and is capable of conducting very large current densities. By aligning the two-dimensional Cu-O layers which carry the current in the superconducting state in the a- and b-directions, i.e., within the basal plane, a high degree of crystalline axes alignment is provided between adjacent grains permitting the conduction of high current densities. The highly anisotropic diamagnetic susceptibility of the polycrystalline metal oxide material permits the use of an applied magnetic field to orient the individual crystals when in the superconducting state to substantially increase current transport between adjacent grains. In another embodiment, the anisotropic paramagnetic susceptibility of rare-earth ions substituted into the oxide material is made use of as an applied magnetic field orients the particles in a preferential direction. This latter operation can be performed with the material in the normal (non-superconducting) state. 4 figs.

Capone, D.W.; Dunlap, B.D.; Veal, B.W.

1990-07-17T23:59:59.000Z

170

Magnetic preferential orientation of metal oxide superconducting materials  

DOE Patents [OSTI]

A superconductor comprised of a polycrystalline metal oxide such as YBa.sub.2 Cu.sub.3 O.sub.7-X (where 0metal oxide material permits the use of an applied magnetic field to orient the individual crystals when in the superconducting state to substantially increase current transport between adjacent grains. In another embodiment, the anisotropic paramagnetic susceptibility of rare-earth ions substituted into the oxide material is made use of as an applied magnetic field orients the particles in a preferential direction. This latter operation can be performed with the material in the normal (non-superconducting) state.

Capone, Donald W. (Bolingbrook, IL); Dunlap, Bobby D. (Bolingbrook, IL); Veal, Boyd W. (Downers Grove, IL)

1990-01-01T23:59:59.000Z

171

Electrodepositionof Metal Alloyand Mixed Oxide Films Usinga Single-PrecursorTetranuclearCopper-NickelComplex  

E-Print Network [OSTI]

Compositionally uniform mixed metals, metal oxides, and alloys are used extensively as corrosion protective and catalysts. I-~For example, nickel-containing oxides and alloys are used for oxidative protection of very. Although Cu-Ni alloy deposition has been stud- ied for many years, none of the previous approaches has led

Kounaves, Samuel P.

172

A tight-binding potential for atomistic simulations of carbon interacting with transition metals: Application to the Ni-C system  

E-Print Network [OSTI]

for transition metals, carbon, and transition metal carbides, which has been optimized through a systematicA tight-binding potential for atomistic simulations of carbon interacting with transition metals of the transition metal, is used to obtain a transferable tight-binding model of the carbon-carbon, metal-metal

Paris-Sud XI, Université de

173

Interfacial oxide re-growth in thin film metal oxide III-V semiconductor systems  

SciTech Connect (OSTI)

The Al{sub 2}O{sub 3}/GaAs and HfO{sub 2}/GaAs interfaces after atomic layer deposition are studied using in situ monochromatic x-ray photoelectron spectroscopy. Samples are deliberately exposed to atmospheric conditions and interfacial oxide re-growth is observed. The extent of this re-growth is found to depend on the dielectric material and the exposure temperature. Comparisons with previous studies show that ex situ characterization can result in misleading conclusions about the interface reactions occurring during the metal oxide deposition process.

McDonnell, S.; Dong, H.; Hawkins, J. M.; Brennan, B.; Milojevic, M.; Aguirre-Tostado, F. S.; Zhernokletov, D. M.; Hinkle, C. L.; Kim, J.; Wallace, R. M.

2012-04-02T23:59:59.000Z

174

Use of high-temperature gas-tight electrochemical cells to measure electronic transport and thermodynamics in metal oxides  

SciTech Connect (OSTI)

By using a gas-tight electrochemical cell, the authors can perform high-temperature coulometric titration and measure electronic transport properties to determine the electronic defect structure of metal oxides. This technique reduces the time and expense required for conventional thermogravimetric measurements. The components of the gas-tight coulometric titration cell are an oxygen sensor, Pt/yttria stabilized zirconia (YSZ)/Pt, and an encapsulated metal oxide sample. Based on cell design, both transport and thermodynamic measurements can be performed over a wide range of oxygen partial pressures (pO{sub 2} = 10{sup {minus}35} to 1 atm). This paper describes the high-temperature gas-tight electrochemical cells used to determine electronic defect structures and transport properties for pure and doped-oxide systems, such as YSZ, doped and pure ceria (Ca-CeO{sub 2} and CeO{sub 2}), copper oxides, and copper-oxide-based ceramic superconductors, transition metal oxides, SrFeCo{sub 0.5}O{sub x}, and BaTiO{sub 3}.

Park, J.H.; Ma, B.; Park, E.T. [Argonne National Lab., IL (United States). Energy Technology Div.

1997-10-01T23:59:59.000Z

175

First spectroscopic investigation of the 4d transition metal monocarbide MoC  

E-Print Network [OSTI]

C simply fills the 2 orbital. Next in the 4d metal-carbide series is another well studied mol- ecule, RhFirst spectroscopic investigation of the 4d transition metal monocarbide MoC Dale J. Brugh transition metal monocarbides, of which only FeC,1­3 CoC,4,5 and NiC Ref. 6 have been studied in detail

Morse, Michael D.

176

Cyclic catalytic upgrading of chemical species using metal oxide materials  

DOE Patents [OSTI]

Processes are disclosure which comprise alternately contacting an oxygen-carrying catalyst with a reducing substance, or a lower partial pressure of an oxidizing gas, and then with the oxidizing gas or a higher partial pressure of the oxidizing gas, whereby the catalyst is alternately reduced and then regenerated to an oxygenated state. In certain embodiments, the oxygen-carrying catalyst comprises at least one metal oxide-containing material containing a composition having one of the following formulas: (a) Ce.sub.xB.sub.yB'.sub.zB''O.sub..delta., wherein B=Ba, Sr, Ca, or Zr; B'=Mn, Co, or Fe; B''=Cu; 0.01

White, James H. (Boulder, CO); Schutte, Erick J. (Thornton, CO); Rolfe, Sara L. (Loveland, CO)

2010-11-02T23:59:59.000Z

177

Lithium metal oxide electrodes for lithium cells and batteries  

DOE Patents [OSTI]

A lithium metal oxide positive electrode for a non-aqueous lithium cell is disclosed. The cell is prepared in its initial discharged state and has a general formula xLiMO.sub.2.(1-x)Li.sub.2 M'O.sub.3 in which 0

Thackeray, Michael M. (Naperville, IL); Johnson, Christopher S. (Naperville, IL); Amine, Khalil (Downers Grove, IL); Kim, Jaekook (Naperville, IL)

2004-01-13T23:59:59.000Z

178

Transition metal co-precipitation mechanisms in silicon T. Buonassisi a,*, M. Heuer a,1  

E-Print Network [OSTI]

-temperature annealing, co-localized single-metal silicide phases are observed, consistent with classical models, upon supersaturation, precipitate into their solid equilibrium metal silicide phase (e.g., FeSi2 [6Transition metal co-precipitation mechanisms in silicon T. Buonassisi a,*, M. Heuer a,1 , A

179

A Low Temperature Fully Lithographic Process For Metal–Oxide Field-Effect Transistors  

E-Print Network [OSTI]

We report a low temperature ( ~ 100à °C) lithographic method for fabricating hybrid metal oxide/organic field-effect transistors (FETs) that combine a zinc-indium-oxide (ZIO) semiconductor channel and organic, parylene, ...

Sodini, Charles G.

180

Development of metallic substrate supported planar solid oxide fuel cells fabricated by atmospheric plasma spraying  

Science Journals Connector (OSTI)

A planar solid oxide fuel cell (SOFC) consisting of a cell supported with a porous metallic substrate and a metallic separator has been developed. In the fabrication of the cell, anodes and electrolytes were form...

Shunji Takenoiri; Naruaki Kadokawa; Kazuo Koseki

2000-09-01T23:59:59.000Z

Note: This page contains sample records for the topic "transition metal oxide" 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

Bipolar plating of metal contacts onto oxide interconnection for solid oxide electrochemical cell  

DOE Patents [OSTI]

Disclosed is a method of forming an adherent metal deposit on a conducting layer of a tube sealed at one end. The tube is immersed with the sealed end down into an aqueous solution containing ions of the metal to be deposited. An ionically conducting aqueous fluid is placed inside the tube and a direct current is passed from a cathode inside the tube to an anode outside the tube. Also disclosed is a multi-layered solid oxide fuel cell tube which consists of an inner porous ceramic support tube, a porous air electrode covering the support tube, a non-porous electrolyte covering a portion of the air electrode, a non-porous conducting interconnection covering the remaining portion of the electrode, and a metal deposit on the interconnection.

Isenberg, Arnold O. (Forest Hills Boro, PA)

1987-01-01T23:59:59.000Z

182

High-throughput synthesis and characterization of vanadium mixed metal oxide pigments using synchroton radiation.  

E-Print Network [OSTI]

??UNA range of inorganic vanadium mixed metal oxides, with potential applications as inorganic pigments, have been synthesised and characterised in terms of their crystal structure,… (more)

Russu, Sergio

2008-01-01T23:59:59.000Z

183

E-Print Network 3.0 - active complementary metal-oxide-semiconductor...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

ion-implanted p and n dopants in germanium Summary: wavelength spectrum allowing optoelectronic integra- tion to enhance complementary-metal-oxide- semiconductor... lim- its in...

184

E-Print Network 3.0 - area metal-oxide-semiconductor electron...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

inversion layer mobility Joo-Hiuk Son,a) Seongtae... measured absorption of terahertz radiation pulses by metal-oxide-semiconductor MOS inversion layers... of the...

185

Project Profile: Thermochemical Heat Storage for CSP Based on Multivalent Metal Oxides  

Broader source: Energy.gov [DOE]

General Atomics (GA), under the Thermal Storage FOA, is developing a high-density thermochemical heat storage system based on solid metal oxides.

186

Synergistic Metal–Metal Oxide Nanoparticles Supported Electrocatalytic Graphene for Improved Photoelectrochemical Glucose Oxidation  

Science Journals Connector (OSTI)

Panels a and b in Figure 1 depict the schematic representation of mechanism of glucose oxidation at the graphene–WO3–Au hybrid membrane modified with glucose oxidase (GOD) enzyme. ... The efficiency improvement seems to be due to (1) the enhancement of electron transport through the TiO2 layer by inter-particle necking of primary TiO2 particles and (2) an increase in the recombination resistance at TiO2/QD/electrolyte interfaces by healing the surface states or managing the oxygen vacancies upon N-ion doping. ...

Anitha Devadoss; P. Sudhagar; Santanu Das; Sang Yun Lee; C. Terashima; K. Nakata; A. Fujishima; Wonbong Choi; Yong Soo Kang; Ungyu Paik

2014-03-09T23:59:59.000Z

187

Enrichment of Fe and Ni at metal and oxide grain boundaries in corroded Zircaloy-2  

Science Journals Connector (OSTI)

Atom probe tomography has been used to study for the first time the metal–oxide interface region in Zircaloy-2. Segregation of Fe and Ni to both deformation-induced sub-grain boundaries in the metal and planar features in the oxide has been found. Apparently, the oxide inherits the chemistry of the sub-grain boundaries as the material oxidizes, which may have implications for the waterside corrosion kinetics of the alloy.

G. Sundell; M. Thuvander; H.-O. Andrén

2012-01-01T23:59:59.000Z

188

Bond-order potential for transition metal carbide cluster for the growth simulation of a single-walled carbon nanotube  

E-Print Network [OSTI]

Bond-order potential for transition metal carbide cluster for the growth simulation of a single for transition metal carbide cluster is developed in the form of the bond-order type potential function-order potential; Carbon nanotube; transition metal carbide cluster *Corresponding Author. Fax: +81-3-5841-8653 E

Maruyama, Shigeo

189

Doping-induced metal-insulator transition in aluminum-doped 4H silicon P. Achatz,1,2,a  

E-Print Network [OSTI]

Doping-induced metal-insulator transition in aluminum-doped 4H silicon carbide P. Achatz,1,2,a J an experimental determination of the doping-induced metal-insulator transition in aluminum-doped 4H silicon concentration lying between 6.4 and 8.7 1020 cm-3 for the metal-insulator transition in these epilayers grown

Paris-Sud XI, Université de

190

E-Print Network 3.0 - activated yttrium oxide Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

copper oxide," G. Srinivasan, Guo-mei Wu, and T. T. Srinivasan, J... frequencies in transition metal ion substituted yttrium barium copper oxide superconductors," G. Srinivasan......

191

Microalloying of transition metal silicides by mechanical activation and field-activated reaction  

DOE Patents [OSTI]

Alloys of transition metal suicides that contain one or more alloying elements are fabricated by a two-stage process involving mechanical activation as the first stage and densification and field-activated reaction as the second stage. Mechanical activation, preferably performed by high-energy planetary milling, results in the incorporation of atoms of the alloying element(s) into the crystal lattice of the transition metal, while the densification and field-activated reaction, preferably performed by spark plasma sintering, result in the formation of the alloyed transition metal silicide. Among the many advantages of the process are its ability to accommodate materials that are incompatible in other alloying methods.

Munir, Zuhair A. (Davis, CA); Woolman, Joseph N. (Davis, CA); Petrovic, John J. (Los Alamos, NM)

2003-09-02T23:59:59.000Z

192

Models for transition metal oxides and for protein design  

E-Print Network [OSTI]

A large number of properties of solid state materials can now be predicted with standard first-principles methods such as the Local Density (LDA) or Generalized Gradient Approximation (GGA). However, known problems exist ...

Zhou, Fei, Ph. D. Massachusetts Institute of Technology

2006-01-01T23:59:59.000Z

193

Transition metal oxides on organic semiconductors Yongbiao Zhao a  

E-Print Network [OSTI]

semiconductors (OSs) structure has been widely used in inverted organic optoelectronic devices, including toward in simplifying the fabrication process of the organic optoelectronic devices. Ã? 2014 Elsevier B], have gained great attention because of their wide applications in optoelectronic devices composed

Demir, Hilmi Volkan

194

Copyright A. J. Millis 2013 Columbia University Transition Metal Oxides  

E-Print Network [OSTI]

Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium 2 P°1/2 ? 1.1 1.3 1.5 1.38 1.36 1.28 1.3 1

Millis, Andrew

195

Studies on supported metal oxide-oxide support interactions (an incorporation model)  

SciTech Connect (OSTI)

XRD, XPS, SSIMS, LRS, and FT-IR are used to explore the valency, composition and structure of the dispersed metal oxide species on supports with different structures, i.e., on ceria and {gamma}-alumina. The results indicated that the dispersion of various ionic compounds are proceeded by the incorporation of the metal cations into the surface vacant sites on the support provided that the loading amounts of the compounds are not higher than their dispersion capacities. The key factors determining the dispersion capacities of the ionic compounds are: (1) the surface structure of the support which determines the size and number of the vacant sites available. (2) the valency of the dispersed ionic compound and the size of the anion, from which the shielding effect of the capping anion(s) can be evaluated, and (3) the sizes of the dispersed cations and the vacant sites on the surface, from which the sites can be used for incorporation can be identified. The Quantitative results deduced from the incorporation model and from the independent experiments are consistent, providing further evidence that the model captures the essentials of the interactions between the dispersed metal oxide and support.

Yi Chen; Lin Dong; Y.S. Jin; Bing Xu; Weijie Ji [Nanjing Univ. (China)

1996-12-31T23:59:59.000Z

196

X-RAY ABSORPTION SPECTROSCOPY OF TRANSITION METAL-MAGNESIUM HYDRIDE FILMS  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Spectroscopy of Transition Metal-Magnesium Spectroscopy of Transition Metal-Magnesium Hydride Thin Films T. J. Richardson a, *, B. Farangis a , J. L. Slack a , P. Nachimuthu b , R. Pereira b , N. Tamura b , and M. Rubin a a Environmental Energy Technologies Division, b Advanced Light Source, Ernest Orlando Lawrence Berkeley National Laboratory Berkeley, California 94720, USA *Corresponding author, E-mail address: tjrichardson@lbl.gov Abstract Mixed metal thin films containing magnesium and a first-row transition element exhibit very large changes in both reflectance and transmittance on exposure to hydrogen gas. Changes in electronic structure and coordination of the magnesium and transition metal atoms during hydrogen absorption were studied using dynamic in situ transmission mode X-ray absorption

197

The nature of the metal-insulator transition in silicon germanide quantum wells.  

E-Print Network [OSTI]

??A study of the temperature dependence of the resistivity of gated SiGe quantum well structures has revealed a metal-insulator transition as a function of carrier… (more)

Lam, Jennifer Eleanor.

2009-01-01T23:59:59.000Z

198

Electrical characterization of metal-to-insulator transition in iron silicide thin films on sillicone substrates.  

E-Print Network [OSTI]

??Iron Silicide (FeSi) films deposited on silicon substrates with the native SiO2 layer have shown a Metal-to-Insulator Transition (MIT) of more than four order of… (more)

Weerasinghe, Hasitha C

2006-01-01T23:59:59.000Z

199

Oxidation catalysts comprising metal exchanged hexaaluminate wherein the metal is Sr, Pd, La, and/or Mn  

DOE Patents [OSTI]

The present invention provides metal-exchanged hexaaluminate catalysts that exhibit good catalytic activity and/or stability at high temperatures for extended periods with retention of activity as combustion catalysts, and more generally as oxidation catalysts, that make them eminently suitable for use in methane combustion, particularly for use in natural gas fired gas turbines. The hexaaluminate catalysts of this invention are of particular interest for methane combustion processes for minimization of the generation of undesired levels (less than about 10 ppm) of NOx species. Metal exchanged hexaaluminate oxidation catalysts are also useful for oxidation of volatile organic compounds (VOC), particularly hydrocarbons. Metal exchanged hexaaluminate oxidation catalysts are further useful for partial oxidation, particularly at high temperatures, of reduced species, particularly hydrocarbons (alkanes and alkenes).

Wickham, David (Boulder, CO); Cook, Ronald (Lakewood, CO)

2008-10-28T23:59:59.000Z

200

Self assembled multi-layer nanocomposite of graphene and metal oxide materials  

DOE Patents [OSTI]

Nanocomposite materials having at least two layers, each layer consisting of one metal oxide bonded to at least one graphene layer were developed. The nanocomposite materials will typically have many alternating layers of metal oxides and graphene layers, bonded in a sandwich type construction and will be incorporated into an electrochemical or energy storage device.

Liu, Jun; Aksay, Ilhan A; Choi, Daiwon; Kou, Rong; Nie, Zimin; Wang, Donghai; Yang, Zhenguo

2013-10-22T23:59:59.000Z

Note: This page contains sample records for the topic "transition metal oxide" 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.


201

Self assembled multi-layer nanocomposite of graphene and metal oxide materials  

SciTech Connect (OSTI)

Nanocomposite materials having at least two layers, each layer consisting of one metal oxide bonded to at least one graphene layer were developed. The nanocomposite materials will typically have many alternating layers of metal oxides and graphene layers, bonded in a sandwich type construction and will be incorporated into an electrochemical or energy storage device.

Liu, Jun; Choi, Daiwon; Kou, Rong; Nie, Zimin; Wang, Donghai; Yang, Zhenguo

2014-09-16T23:59:59.000Z

202

Development of a Plasma Arc Manufacturing Process and Machine to Create Metal Oxide Particles in Water From Wire Feedstock.  

E-Print Network [OSTI]

??A plasma arc erosion process can be used to create metal and metal oxide particles in the ultra-fine size range (<70 um). An electric arc… (more)

George, Jonathan Alan 1983-

2010-01-01T23:59:59.000Z

203

Bridged transition-metal complexes and uses thereof for hydrogen separation, storage and hydrogenation  

DOE Patents [OSTI]

The present invention constitutes a class of organometallic complexes which reversibly react with hydrogen to form dihydrides and processes by which these compounds can be utilized. The class includes bimetallic complexes in which two cyclopentadienyl rings are bridged together and also separately .pi.-bonded to two transition metal atoms. The transition metals are believed to bond with the hydrogen in forming the dihydride. Transition metals such as Fe, Mn or Co may be employed in the complexes although Cr constitutes the preferred metal. A multiple number of ancilliary ligands such as CO are bonded to the metal atoms in the complexes. Alkyl groups and the like may be substituted on the cyclopentadienyl rings. These organometallic compounds may be used in absorption/desorption systems and in facilitated transport membrane systems for storing and separating out H.sub.2 from mixed gas streams such as the product gas from coal gasification processes.

Lilga, Michael A. (Richland, WA); Hallen, Richard T. (Richland, WA)

1991-01-01T23:59:59.000Z

204

Bridged transition-metal complexes and uses thereof for hydrogen separation, storage and hydrogenation  

DOE Patents [OSTI]

The present invention constitutes a class of organometallic complexes which reversibly react with hydrogen to form dihydrides and processes by which these compounds can be utilized. The class includes bimetallic complexes in which two cyclopentadienyl rings are bridged together and also separately .pi.-bonded to two transition metal atoms. The transition metals are believed to bond with the hydrogen in forming the dihydride. Transition metals such as Fe, Mn or Co may be employed in the complexes although Cr constitutes the preferred metal. A multiple number of ancilliary ligands such as CO are bonded to the metal atoms in the complexes. Alkyl groups and the like may be substituted on the cyclopentadienyl rings. These organometallic compounds may be used in absorption/desorption systems and in facilitated transport membrane systems for storing and separating out H.sub.2 from mixed gas streams such as the produce gas from coal gasification processes.

Lilga, Michael A. (Richland, WA); Hallen, Richard T. (Richland, WA)

1990-01-01T23:59:59.000Z

205

Bridged transition-metal complexes and uses thereof for hydrogen separation, storage and hydrogenation  

DOE Patents [OSTI]

The present invention constitutes a class of organometallic complexes which reversibly react with hydrogen to form dihydrides and processes by which these compounds can be utilized. The class includes bimetallic complexes in which two cyclopentadienyl rings are bridged together and also separately [pi]-bonded to two transition metal atoms. The transition metals are believed to bond with the hydrogen in forming the dihydride. Transition metals such as Fe, Mn or Co may be employed in the complexes although Cr constitutes the preferred metal. A multiple number of ancillary ligands such as CO are bonded to the metal atoms in the complexes. Alkyl groups and the like may be substituted on the cyclopentadienyl rings. These organometallic compounds may be used in absorption/desorption systems and in facilitated transport membrane systems for storing and separating out H[sub 2] from mixed gas streams such as the producer gas from coal gasification processes. 3 figs.

Lilga, M.A.; Hallen, R.T.

1990-08-28T23:59:59.000Z

206

Bridged transition-metal complexes and uses thereof for hydrogen separation, storage and hydrogenation  

DOE Patents [OSTI]

The present invention constitutes a class of organometallic complexes which reversibly react with hydrogen to form dihydrides and processes by which these compounds can be utilized. The class includes bimetallic complexes in which two cyclopentadienyl rings are bridged together and also separately [pi]-bonded to two transition metal atoms. The transition metals are believed to bond with the hydrogen in forming the dihydride. Transition metals such as Fe, Mn or Co may be employed in the complexes although Cr constitutes the preferred metal. A multiple number of ancillary ligands such as CO are bonded to the metal atoms in the complexes. Alkyl groups and the like may be substituted on the cyclopentadienyl rings. These organometallic compounds may be used in absorption/desorption systems and in facilitated transport membrane systems for storing and separating out H[sub 2] from mixed gas streams such as the product gas from coal gasification processes. 3 figures.

Lilga, M.A.; Hallen, R.T.

1991-10-15T23:59:59.000Z

207

Stabilization of Electrocatalytic Metal Nanoparticles at Metal...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Electrocatalytic Metal Nanoparticles at Metal-Metal Oxide-Graphene Triple Junction Points. Stabilization of Electrocatalytic Metal Nanoparticles at Metal-Metal Oxide-Graphene...

208

Sulfur resistance of Group VIII transition metal promoted nickel catalysts for synthesis gas methanation  

E-Print Network [OSTI]

SULFUR RESISTANCE OF GROUP VIII TRANSITION METAL PROMOTED NICKEL CATALYSTS FOR SYNTHESIS GAS METHANATION A Thesis by KELLEE HALL HAMLIN Submitted to the Graduate College of Texas AgrM University in partial fulfillment of the requirement...: Aydin Akger n (Chairman of Co 'ttee) Ahme M. Gadalla (Member) Michael . Rosynek (Member) aries D. Holland . ( ead of Department) May 1986 ABSTRACT Sulfur Resistance of Group VIII Transition Metal Promoted Nickel Catalysts For Synthesis Gas...

Hamlin, Kellee Hall

2012-06-07T23:59:59.000Z

209

Electric pulse induced resistance change effect in manganites due to polaron localization at the metal-oxide interfacial region  

Science Journals Connector (OSTI)

Combining pulse-probe measurements as well as local transport measurements in an electron microscope system by a simultaneous monitoring of the structural changes, we show that the nonvolatile electric pulse induced resistance change in Ca-doped praseodymium manganite is related to a polaron order-disorder transition, modified by electronic band bending in the vicinity of an interface to a metallic electrode. A pronounced resistance change requires a critical distance between the two electrode and/or oxide interfaces to form an insulating incommensurate polaron-ordered phase during the initialization of the device. Based on these observations, a qualitative model for the electronic structure of the metal-oxide interface is developed.

Ch. Jooss, J. Hoffmann, J. Fladerer, M. Ehrhardt, T. Beetz, L. Wu, and Y. Zhu

2008-04-23T23:59:59.000Z

210

X-Ray Absorption Spectroscopy of Transition Metal-Magnesium Hydride Thin  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

X-Ray Absorption Spectroscopy of Transition Metal-Magnesium Hydride Thin X-Ray Absorption Spectroscopy of Transition Metal-Magnesium Hydride Thin Films Title X-Ray Absorption Spectroscopy of Transition Metal-Magnesium Hydride Thin Films Publication Type Journal Article LBNL Report Number LBNL-50574 Year of Publication 2002 Authors Richardson, Thomas J., Baker Farangis, Jonathan L. Slack, Ponnusamy Nachimuthu, Rupert C. C. Perera, Nobumichi Tamura, and Michael D. Rubin Journal Journal of Alloys and Compounds Volume 356-357 Start Page 204 Pagination 204-207 Date Published 08/2003 Keywords A. hydrogen storage materials, NEXAFS, thin film s; C. EXAFS, x-ray diffraction Abstract Mixed metal thin films containing magnesium and a first-row transition element exhibit very large changes in both reflectance and transmittance on exposure to hydrogen gas. Changes in electronic structure and coordination of the magnesium and transition metal atoms during hydrogen absorption were studied using dynamic in situ transmission mode X-ray absorption spectroscopy. Mg K-edge and Ni, Co, and Ti L-edge spectra reflect both reversible and irreversible changes in the metal environments. A significant shift in the nickel L absorption edge shows it to be an active participant in hydride formation. The effect on cobalt and titanium is much less dramatic, suggesting that these metals act primarily as catalysts for formation of magnesium hydride.

211

Reversible mechanism for spin crossover in transition-metal cyanides  

E-Print Network [OSTI]

We report the mechanisms for reversible and repeatable spin transition in a Prussian blue analog crystal, KCo[Fe(CN)[subscript 6

Kabir, Mohammad Mukul

212

Copper-induced oxidative stress in three-spined stickleback : relationship with hepatic metal levels  

E-Print Network [OSTI]

contamination of aquatic ecosystems by heavy metals. Among them, copper is a widespread pollutant found, 1999). Although this metal is a required element, high concentrations appear to be toxic to freshwater1 Copper-induced oxidative stress in three-spined stickleback : relationship with hepatic metal

Paris-Sud XI, Université de

213

Metal-insulator transition and electrically driven memristive characteristics of SmNiO{sub 3} thin films  

SciTech Connect (OSTI)

The correlated oxide SmNiO{sub 3} (SNO) exhibits an insulator to metal transition (MIT) at 130 deg. C in bulk form. We report on synthesis and electron transport in SNO films deposited on LaAlO{sub 3} (LAO) and Si single crystals. X-ray diffraction studies show that compressively strained single-phase SNO grows epitaxially on LAO while on Si, mixed oxide phases are observed. MIT is observed in resistance-temperature measurements in films grown on both substrates, with charge transport in-plane for LAO/SNO films and out-of-plane for Si/SNO films. Electrically driven memristive behavior is realized in LAO/SNO films, suggesting that SNO may be relevant for neuromorphic devices.

Ha, Sieu D.; Aydogdu, Gulgun H.; Ramanathan, Shriram [School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachussets 02138 (United States)

2011-01-03T23:59:59.000Z

214

Toward Photochemical Water Splitting Using Band-Gap-Narrowed Semiconductors and Transition-Metal Based Molecular Catalysts  

SciTech Connect (OSTI)

We are carrying out coordinated theoretical and experimental studies of toward photochemical water splitting using band-gap-narrowed semiconductors (BGNSCs) with attached multi-electron molecular water oxidation and hydrogen production catalysts. We focus on the coupling between the materials properties and the H{sub 2}O redox chemistry, with an emphasis on attaining a fundamental understanding of the individual elementary steps in the following four processes: (1) Light-harvesting and charge-separation of stable oxide or oxide-derived semiconductors for solar-driven water splitting, including the discovery and characterization of the behavior of such materials at the aqueous interface; (2) The catalysis of the four-electron water oxidation by dinuclear hydroxo transition-metal complexes with quinonoid ligands, and the rational search for improved catalysts; (3) Transfer of the design principles learned from the elucidation of the DuBois-type hydrogenase model catalysts in acetonitrile to the rational design of two-electron hydrogen production catalysts for aqueous solution; (4) Combining these three elements to examine the function of oxidation catalysts on BGNSC photoanode surfaces and hydrogen production catalysts on cathode surfaces at the aqueous interface to understand the challenges to the efficient coupling of the materials functions.

Muckerman,J.T.; Rodriguez, J.A.; Fujita, E.

2009-06-07T23:59:59.000Z

215

Femtosecond NEXAFS of Photoinduced Insulator-Metal Transition in VO2  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Femtosecond NEXAFS of Femtosecond NEXAFS of Photoinduced Insulator-Metal Transition in VO2 Femtosecond NEXAFS of Photoinduced Insulator-Metal Transition in VO2 Print Wednesday, 28 September 2005 00:00 The grand goal motivating femtosecond studies of condensed-matter dynamics is to directly measure the structural pathways that connect different crystallographic, electronic, and magnetic phases of solids, as well as the short-lived transition states between reactants and products in chemical and biochemical reactions. Researchers from Berkeley Lab and the Université du Québec have taken a big step forward by adding femtosecond x-ray spectroscopy to the experimental toolkit with their first use of the laser-slicing technique to study the photoinduced metal-insulator phase transition in vanadium dioxide (VO2).

216

J. Am. Chem. SOC.1994,116, 8733-8740 8733 Energetics of Third-Row Transition Metal Methylidene Ions  

E-Print Network [OSTI]

J. Am. Chem. SOC.1994,116, 8733-8740 8733 Energetics of Third-Row Transition Metal Methylidene Ions methylidene ions MCH2+ of the 5d transition series. On the basis of our calculations and available first- row (3d) and second-row (4d) transition metals. Indeed, recent gas-phase studies of the reactions

Goddard III, William A.

217

New Routes to Transition Metal-Carbido Species: Synthesis and Characterization of the Carbon-Centered Trigonal Prismatic Clusters  

E-Print Network [OSTI]

New Routes to Transition Metal-Carbido Species: Synthesis and Characterization of the Carbon 94720-1460 Received May 5, 2003; E-mail: jlong@cchem.berkeley.edu Transition metal-carbon clusters have long been of interest as fragments of refractory metal carbides and models for intermediates

218

Regenerable MgO promoted metal oxide oxygen carriers for chemical looping combustion  

DOE Patents [OSTI]

The disclosure provides an oxygen carrier comprised of a plurality of metal oxide particles in contact with a plurality of MgO promoter particles. The MgO promoter particles increase the reaction rate and oxygen utilization of the metal oxide when contacting with a gaseous hydrocarbon at a temperature greater than about 725.degree. C. The promoted oxide solid is generally comprised of less than about 25 wt. % MgO, and may be prepared by physical mixing, incipient wetness impregnation, or other methods known in the art. The oxygen carrier exhibits a crystalline structure of the metal oxide and a crystalline structure of MgO under XRD crystallography, and retains these crystalline structures over subsequent redox cycles. In an embodiment, the metal oxide is Fe.sub.2O.sub.3, and the gaseous hydrocarbon is comprised of methane.

Siriwardane, Ranjani V.; Miller, Duane D.

2014-08-19T23:59:59.000Z

219

Mechanisms of transition-metal catalyzed additions to olefins  

E-Print Network [OSTI]

....................................................................................................... 33 10 Reaction schematic for 13C KIE studies on free-radical polymerization and ATRP ........... 34 11 Transition structures for (a) the addition of methyl radical to ethylene and (b) the addition of formylmethyl radical to acrolein...

Nowlan, Daniel Thomas

2005-08-29T23:59:59.000Z

220

Neutral bimetallic transition metal phenoxyiminato catalysts and related polymerization methods  

DOE Patents [OSTI]

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

Note: This page contains sample records for the topic "transition metal oxide" 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

Magnetization-driven Metal-insulator Transition in Strongly...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Israel Science Foundation Grant No. 63306. NHMFL is supported by NSF Cooperative Agreement No. DMR-0654118, the State of Florida, and the DOE. Magnetization-driven Metal-insulator...

222

Ternary rare earth and actinoid transition metal carbides viewed as carbometalates  

SciTech Connect (OSTI)

Ternary carbides A{sub x}T{sub y}C{sub z} (A=rare earth metals and actinoids; T=transition metals) with monoatomic species C{sup 4-} as structural entities are classified according to the criteria (i) metal to carbon ratio, (ii) coordination number of the transition metal by carbon atoms, and (iii) the dimensionality of the anionic network [T{sub y}C{sub z}]{sup n-}. Two groups are clearly distinguishable, depending on the metal to carbon ratio. Those where this ratio is equal to or smaller than 2 may be viewed as carbometalates, thus extending the sequence of complex anions from fluoro-, oxo-, and nitridometalates to carbometalates. The second group, metal-rich carbides with metal to carbon ratios equal to or larger than 4 is better viewed as typical intermetallics (''interstitial carbides''). The chemical bonding properties have been investigated by analyzing the Crystal Orbital Hamilton Population (COHP). The chemical bonding situation with respect to individual T-C bonds is similar in both classes. The main difference is the larger number of metal-metal bonds in the crystal structures of the metal-rich carbides.

Dashjav, Enkhtsetseg [Max-Planck-Institut fuer Chemische Physik fester Stoffe, Noethnitzer Strasse 40, D-01187 Dresden (Germany); Kreiner, Guido [Max-Planck-Institut fuer Chemische Physik fester Stoffe, Noethnitzer Strasse 40, D-01187 Dresden (Germany); Schnelle, Walter [Max-Planck-Institut fuer Chemische Physik fester Stoffe, Noethnitzer Strasse 40, D-01187 Dresden (Germany); Wagner, Frank R. [Max-Planck-Institut fuer Chemische Physik fester Stoffe, Noethnitzer Strasse 40, D-01187 Dresden (Germany); Kniep, Ruediger [Max-Planck-Institut fuer Chemische Physik fester Stoffe, Noethnitzer Strasse 40, D-01187 Dresden (Germany)], E-mail: Kniep@cpfs.mpg.de; Jeitschko, Wolfgang [Institut fuer Anorganische und Analytische Chemie, Universitaet Muenster, Wilhelm-Klemm-Strasse 8, D-48149 Muenster (Germany)], E-mail: jeitsch@uni-muenster.de

2007-02-15T23:59:59.000Z

223

Cyclopentadienyl-containing low-valent early transition metal olefin polymerization catalysts  

DOE Patents [OSTI]

A catalyst system useful to polymerize and co-polymerize polar and non-polar olefin monomers is formed by in situ reduction with a reducing agent of a catalyst precursor comprising {Cp*MRR'.sub.n }.sup.+ {A}.sup.- wherein Cp* is a cyclopentadienyl or substituted cyclopentadienyl moiety; M is an early transition metal; R is a C.sub.1 -C.sub.20 hydrocarbyl; R' are independently selected from hydride, C.sub.1 -C.sub.20 hydrocarbyl, SiR".sub.3, NR".sub.2, OR", SR", GeR".sub.3, and SnR".sub.3 containing groups (R"=C.sub.1 -C.sub.10 hydrocarbyl); n is an integer selected to balance the oxidation state of M; and A is a suitable non-coordinating anionic cocatalyst or precursor. This catalyst system may form stereoregular olefin polymers including syndiotactic polymers of styrene and methylmethacrylate and isotactic copolymers of polar and nonpolar olefin monomers such as methylmethacrylate and styrene.

Marks, Tobin J. (Evanston, IL); Luo, Lubin (Baton Rouge, LA); Yoon, Sung Cheol (Evanston, IL)

2003-04-08T23:59:59.000Z

224

Cyclopentadienyl-Containing Low-Valent Early Transition Metal Olefin Polymerization Catalysts  

DOE Patents [OSTI]

A catalyst system useful to polymerize and co-polymerize polar and non-polar olefin monomers is formed by in situ reduction with a reducing agent of a catalyst precursor comprising {Cp*MRR'.sub.n }.sup.+ {A}.sup.- wherein Cp* is a cyclopentadienyl or substituted cyclopentadienyl moiety; M is an early transition metal; R is a C.sub.1 -C.sub.20 hydrocarbyl; R' are independently selected from hydride, C.sub.1 -C.sub.20 hydrocarbyl, SiR".sub.3, NR".sub.2, OR", SR", GeR".sub.3, SnR".sub.3, and C.dbd.C-containing groups (R"=C.sub.1 -C.sub.10 hydrocarbyl); n is an integer selected to balance the oxidation state of M; and A is a suitable non-coordinating anionic cocatalyst or precursor. This catalyst system may form stereoregular olefin polymers including syndiotactic polymers of styrene and methylmethacrylate and isotactic copolymers of polar and nonpolar olefin monomers such as methylmethacrylate and styrene.

Marks, Tobin J. (Evanston, IL); Luo, Lubin (Baton Rouge, LA); Yoon, Sung Cheol (Evanston, IL)

2004-06-08T23:59:59.000Z

225

Reactivity of biogenic manganese oxide for metal sequestration and photochemistry: Computational solid state physics study  

SciTech Connect (OSTI)

Many microbes, including both bacteria and fungi, produce manganese (Mn) oxides by oxidizing soluble Mn(II) to form insoluble Mn(IV) oxide minerals, a kinetically much faster process than abiotic oxidation. These biogenic Mn oxides drive the Mn cycle, coupling it with diverse biogeochemical cycles and determining the bioavailability of environmental contaminants, mainly through strong adsorption and redox reactions. This mini review introduces recent findings based on quantum mechanical density functional theory that reveal the detailed mechanisms of toxic metal adsorption at Mn oxide surfaces and the remarkable role of Mn vacancies in the photochemistry of these minerals.

Kwon, K.D.; Sposito, G.

2010-02-01T23:59:59.000Z

226

Transition from metallic to tunneling-type conductance in metal-metal and normal-metal–superconductor point contacts  

Science Journals Connector (OSTI)

We have investigated the microshort–to–tunneling crossover in normal-normal (N-N) and normal-metal–superconductor (N-S) point-contact junctions at 4.2 K as the junction conductance (G0) is varied. The microshort (or ‘‘metallic’’) point contact with the dynamic conductance G (V) having a negative derivative with respect to bias V (i.e., ?G/?V0 when G0?3–5 mS. We show that this is the region where the contact radius ? is a few times kF-1 (kF is the Fermi wave vector) and the crossover in the sign of ?G/?V occurs due to electron confinement in a length scale comparable to kF-1. The effect of confinement is to make the electrons crossing the constriction evanescent in nature as the junction size is reduced progressively and the energy for lateral confinement becomes comparable to EF. We argue that in this extreme ballistic regime, the classical Sharvin approach breaks down as quantum effects due to electron confinement takes over. This happens much before ‘‘single-atom’’ contact is reached which signals the onset of vacuum tunneling. As a further test of the electron confinement effects in point contacts, we investigated clean N-S microshorts showing near-ideal Andreev reflection. We find that in N-S junctions, the Andreev reflection (which is a manifestation of superconductivity) gradually vanishes when the contact radius ??0.1? (? is the coherence length) and the energy cost of electron confinement is larger than the superconducting energy gap ?.

H. Srikanth and A. K. Raychaudhuri

1992-12-01T23:59:59.000Z

227

Oxidative Dissolution of Nickel Metal in Hydrogenated Hydrothermal Solutions  

SciTech Connect (OSTI)

A platinum-lined, flowing autoclave facility is used to investigate the solubility behavior of metallic nickel in hydrogenated ammonia and sodium hydroxide solutions between 175 and 315 C. The solubility measurements were interpreted by means of an oxidative dissolution reaction followed by a sequence of Ni(II) ion hydrolysis reactions: Ni(s) + 2H+(aq) = Ni2+(aq) + H2(g) and Ni{sup 2+}(aq) + nH{sub 2}O = Ni(OH){sub n}{sup 2-n}(aq) + nH{sup +}(aq) where n = 1 and 2. Gibbs energies associated with these reaction equilibria were determined from a least-squares analysis of the data. The extracted thermochemical properties ({Delta}fG{sup 0}, {Delta}fH{sup 0} and S{sup 0}) for Ni2{sup +}(aq), Ni(OH){sup +}(aq) and Ni(OH){sub 2}(aq) were found to be consistent with those determined in a previous solubility study of NiO/Ni(OH){sub 2} conducted in our laboratory. The thermodynamic basis of the Ni/NiO phase boundary in aqueous solutions is examined to show that Ni(s) is stable relative to NiO(s) in solutions saturated at 25 C with 1 atm H{sub 2} for temperatures below 309 C.

Ziemniak SE, Guilmette PA, Turcotte RA, Tunison HM

2007-03-27T23:59:59.000Z

228

Notes on the photo-induced characteristics of transition metal-doped and undoped titanium dioxide thin films  

E-Print Network [OSTI]

­gel method using titanium n-butoxide, acetylacetone, and transition metal acetylacetonates as precursors dioxide with transition met- als such as iron [28], cobalt [29], nickel [30], manganese [31], chro- mium

Cirkva, Vladimir

229

Fabrication of carbon nanotube films from alkyne-transition metal complexes  

DOE Patents [OSTI]

A simple method for the production or synthesis of carbon nanotubes as free-standing films or nanotube mats by the thermal decomposition of transition metal complexed alkynes with aryl, alkyl, alkenyl, or alkynyl substituents. In particular, transition metal (e.g. Co, Ni, Fe, Mo) complexes of diarylacetylenes, e.g. diphenylacetylene, and solid mixtures of these complexes with suitable, additional carbon sources are heated in a vessel. More specifically, the heating of the transition metal complex is completed at a temperature between 400-800.degree. C. and more particularly 550-700.degree. C. for between 0.1 to 24 hours and more particularly 0.5-3 hours in a sealed vessel under a partial pressure of argon or helium.

Iyer, Vivekanantan S. (Delft, NL); Vollhardt, K. Peter C. (Oakland, CA)

2007-08-28T23:59:59.000Z

230

Near-infrared photodetector consisting of J-aggregating cyanine dye and metal oxide thin films  

E-Print Network [OSTI]

We demonstrate a near-infrared photodetector that consists of a thin film of the J-aggregating cyanine dye, U3, and transparent metal-oxide charge transport layers. The high absorption coefficient of the U3 film, combined ...

Osedach, Timothy P.

231

Low temperature lithographically patterned metal oxide transistors for large area electronics  

E-Print Network [OSTI]

Optically transparent, wide bandgap metal oxide semiconductors are a promising candidate for large-area electronics technologies that require lightweight, temperature-sensitive flexible substrates. Because these thin films ...

Wang, Annie I. (Annie I-Jen), 1981-

2011-01-01T23:59:59.000Z

232

Long-term research in Japan: amorphous metals, metal oxide varistors, high-power semiconductors and superconducting generators  

SciTech Connect (OSTI)

The review revealed that significant activity is under way in the research of amorphous metals, but that little fundamental work is being pursued on metal oxide varistors and high-power semiconductors. Also, the investigation of long-term research program plans for superconducting generators reveals that activity is at a low level, pending the recommendations of a study currently being conducted through Japan's Central Electric Power Council.

Hane, G.J.; Yorozu, M.; Sogabe, T.; Suzuki, S.

1985-04-01T23:59:59.000Z

233

Studies of high temperature ternary phases in mixed-metal-rich early transition metal sulfide and phosphide systems  

SciTech Connect (OSTI)

Investigations of ternary mixed early transition metal-rich sulfide and phosphide systems resulted in the discovery of new structures and new phases. A new series of Zr and Hf - group V transition metal - sulfur K-phases was synthesized and crystallographically characterized. When the group V transition metal was Nb or Ta, the unit cell volume was larger than any previously reported K-phase. The presence of adventitious oxygen was determined in two K-phases through a combination of neutron scattering and X-ray diffraction experiments. A compound Hf{sub 10}Ta{sub 3}S{sub 3} was found to crystallize in a new-structure type similar to the known gamma brasses. This structure is unique in that it is the only reported {open_quotes}stuffed{close_quotes} gamma-brass type structure. The metal components, Hf and Ta, are larger in size and more electropositive than the metals found in normal gamma brasses (e.g. Cu and Zn) and because of the larger metallic radii, sulfur can be incorporated into the structure where it plays an integral role in stabilizing this phase relative to others. X-ray single-crystal, X-ray powder and neutron powder refinements were performed on this structure. A new structure was found in the ternary Nb-Zr-P system which has characteristics in common with many known early transition metal-rich sulfides, selenides, and phosphides. This structure has the simplest known interconnection of the basic building blocks known for this structural class. Anomalous scattering was a powerful tool for differentiating between Zr and Nb when using Mo K{alpha} X-radiation. The compounds ZrNbP and HfNbP formed in the space group Prima with the simple Co{sub 2}Si structure which is among the most common structures found for crystalline solid materials. Solid solution compounds in the Ta-Nb-P, Ta-Zr-P, Nb-Zr-P, Hf-Nb-P, and Hf-Zr-S systems were crystallographically characterized. The structural information corroborated ideas about bonding in metal-rich compounds.

Marking, G.A.

1994-01-04T23:59:59.000Z

234

Investigation of metal-insulator like transition through the ab initio density matrix renormalization group approach  

E-Print Network [OSTI]

We have studied the Metal-Insulator like Transition (MIT) in lithium and beryllium ring-shaped clusters through ab initio Density Matrix Renormalization Group (DMRG) method. Performing accurate calculations for different interatomic distances and using Quantum Information Theory (QIT) we investigated the changes occurring in the wavefunction between a metallic-like state and an insulating state built from free atoms. We also discuss entanglement and relevant excitations among the molecular orbitals in the Li and Be rings and show that the transition bond length can be detected using orbital entropy functions. Also, the effect of different orbital basis on the effectiveness of the DMRG procedure is analyzed comparing the convergence behavior.

Fertitta, E; Barcza, G; Legeza, Ö

2014-01-01T23:59:59.000Z

235

Nanoscale structural evolution of electrically driven insulator to metal transition in vanadium dioxide  

SciTech Connect (OSTI)

The structural evolution of tensile strained vanadium dioxide thin films was examined across the electrically driven insulator-to-metal transition by nanoscale hard X-ray diffraction. A metallic filament with rutile (R) structure was found to be the dominant conduction pathway for an electrically driven transition, while the majority of the channel area remained in the monoclinic M1 phase. The filament dimensions were estimated using simultaneous electrical probing and nanoscale X-ray diffraction. Analysis revealed that the width of the conducting channel can be tuned externally using resistive loads in series, enabling the M1/R phase ratio in the phase coexistence regime to be tuned.

Freeman, Eugene, E-mail: exf181@psu.edu; Shukla, Nikhil; Datta, Suman [Department of Electrical Engineering, Pennsylvania State University, University Park, Pennsylvania 16802 (United States)] [Department of Electrical Engineering, Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Stone, Greg; Engel-Herbert, Roman; Gopalan, Venkatraman [Department of Materials Science and Engineering, Pennsylvania State University, University Park, Pennsylvania 16802 (United States)] [Department of Materials Science and Engineering, Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Paik, Hanjong [Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853 (United States)] [Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853 (United States); Moyer, Jarrett A. [Department of Physics and Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States)] [Department of Physics and Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States); Cai, Zhonghou; Wen, Haidan [Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States)] [Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Schlom, Darrell G. [Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853 (United States) [Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853 (United States); Kavli Institute at Cornell for Nanoscale Science, Ithaca, New York 14853 (United States)

2013-12-23T23:59:59.000Z

236

Steam Reforming on Transition-metal Carbides from Density-functional Theory  

SciTech Connect (OSTI)

A screening study of the steam reforming reaction on clean and oxygen covered early transition-metal carbides surfaces is performed by means of density-functional theory calculations. It is found that carbides provide a wide spectrum of reactivities, from too reactive via suitable to too inert. Several molybdenum-based systems are identified as possible steam reforming catalysts. The findings suggest that carbides provide a playground for reactivity tuning, comparable to the one for pure metals.

Vojvodic, Aleksandra

2012-05-11T23:59:59.000Z

237

M5Si3(M=Ti, Nb, Mo) Based Transition-Metal Silicides for High Temperature Applications  

SciTech Connect (OSTI)

Transition metal silicides are being considered for future engine turbine components at temperatures up to 1600 C. Although significant improvement in high temperature strength, room temperature fracture toughness has been realized in the past decade, further improvement in oxidation resistance is needed. Oxidation mechanism of Ti{sub 5}Si{sub 3}-based alloys was investigated. Oxidation behavior of Ti{sub 5}Si{sub 3}-based alloy strongly depends on the atmosphere. Presence of Nitrogen alters the oxidation behavior of Ti{sub 5}Si{sub 3} by nucleation and growth of nitride subscale. Ti{sub 5}Si{sub 3.2} and Ti{sub 5}Si{sub 3}C{sub 0.5} alloys exhibited an excellent oxidation resistance in nitrogen bearing atmosphere due to limited dissolution of nitrogen and increased Si/Ti activity ratio. MoSi{sub 2} coating developed by pack cementation to protect Mo-based Mo-Si-B composites was found to be effective up to 1500 C. Shifting coating composition to T1+T2+Mo{sub 3}Si region showed the possibility to extend the coating lifetime above 1500 C by more than ten times via formation of slow growing Mo{sub 3}Si or T2 interlayer without sacrificing the oxidation resistance of the coating. The phase equilibria in the Nb-rich portion of Nb-B system has been evaluated experimentally using metallographic analysis and differential thermal analyzer (DTA). It was shown that Nb{sub ss} (solid solution) and NbB are the only two primary phases in the 0-40 at.% B composition range, and the eutectic reaction L {leftrightarrow} Nb{sub SS} + NbB was determined to occur at 2104 {+-} 5 C by DTA.

Zhihong Tang

2007-12-01T23:59:59.000Z

238

Emerging Applications of Liquid Metals Featuring Surface Oxides  

Science Journals Connector (OSTI)

Figure 4. 3D printing of free-standing liquid metal structures. ... Ladd, C.; So, J.-H.; Muth, J.; Dickey, M. D.3D Printing of Free Standing Liquid Metal Microstructures Adv. ... 3D Printing of Free Standing Liquid Metal Microstructures ...

Michael D. Dickey

2014-10-06T23:59:59.000Z

239

Femtosecond NEXAFS of Photoinduced Insulator-Metal Transition in VO2  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Femtosecond NEXAFS of Photoinduced Insulator-Metal Transition in VO2 Print Femtosecond NEXAFS of Photoinduced Insulator-Metal Transition in VO2 Print The grand goal motivating femtosecond studies of condensed-matter dynamics is to directly measure the structural pathways that connect different crystallographic, electronic, and magnetic phases of solids, as well as the short-lived transition states between reactants and products in chemical and biochemical reactions. Researchers from Berkeley Lab and the Université du Québec have taken a big step forward by adding femtosecond x-ray spectroscopy to the experimental toolkit with their first use of the laser-slicing technique to study the photoinduced metal-insulator phase transition in vanadium dioxide (VO2). Ultrafast X-Ray Science Only a moment's reflection is enough to confirm that the world around us is in constant flux. That change is everywhere and ever present yields the conclusion that extracting the full story requires time-resolved experiments in which one can trace in detail on the time scale on which atoms move the pathways (including transient intermediate states) by which matter changes from one form to another (phase transitions). For example, the making and breaking of chemical bonds and the rearrangement of atoms, which occur on the fundamental time scale of a vibrational period (about 100 femtoseconds), ultimately determine the course of phase transitions in solids, the kinetic pathways of chemical reactions, and even the efficiency and function of biological processes.

240

Femtosecond NEXAFS of Photoinduced Insulator-Metal Transition in VO2  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Femtosecond NEXAFS of Photoinduced Insulator-Metal Transition in VO2 Print Femtosecond NEXAFS of Photoinduced Insulator-Metal Transition in VO2 Print The grand goal motivating femtosecond studies of condensed-matter dynamics is to directly measure the structural pathways that connect different crystallographic, electronic, and magnetic phases of solids, as well as the short-lived transition states between reactants and products in chemical and biochemical reactions. Researchers from Berkeley Lab and the Université du Québec have taken a big step forward by adding femtosecond x-ray spectroscopy to the experimental toolkit with their first use of the laser-slicing technique to study the photoinduced metal-insulator phase transition in vanadium dioxide (VO2). Ultrafast X-Ray Science Only a moment's reflection is enough to confirm that the world around us is in constant flux. That change is everywhere and ever present yields the conclusion that extracting the full story requires time-resolved experiments in which one can trace in detail on the time scale on which atoms move the pathways (including transient intermediate states) by which matter changes from one form to another (phase transitions). For example, the making and breaking of chemical bonds and the rearrangement of atoms, which occur on the fundamental time scale of a vibrational period (about 100 femtoseconds), ultimately determine the course of phase transitions in solids, the kinetic pathways of chemical reactions, and even the efficiency and function of biological processes.

Note: This page contains sample records for the topic "transition metal oxide" from the National Library of EnergyBeta (NLEBeta).
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241

Femtosecond NEXAFS of Photoinduced Insulator-Metal Transition in VO2  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Femtosecond NEXAFS of Photoinduced Insulator-Metal Transition in VO2 Print Femtosecond NEXAFS of Photoinduced Insulator-Metal Transition in VO2 Print The grand goal motivating femtosecond studies of condensed-matter dynamics is to directly measure the structural pathways that connect different crystallographic, electronic, and magnetic phases of solids, as well as the short-lived transition states between reactants and products in chemical and biochemical reactions. Researchers from Berkeley Lab and the Université du Québec have taken a big step forward by adding femtosecond x-ray spectroscopy to the experimental toolkit with their first use of the laser-slicing technique to study the photoinduced metal-insulator phase transition in vanadium dioxide (VO2). Ultrafast X-Ray Science Only a moment's reflection is enough to confirm that the world around us is in constant flux. That change is everywhere and ever present yields the conclusion that extracting the full story requires time-resolved experiments in which one can trace in detail on the time scale on which atoms move the pathways (including transient intermediate states) by which matter changes from one form to another (phase transitions). For example, the making and breaking of chemical bonds and the rearrangement of atoms, which occur on the fundamental time scale of a vibrational period (about 100 femtoseconds), ultimately determine the course of phase transitions in solids, the kinetic pathways of chemical reactions, and even the efficiency and function of biological processes.

242

Femtosecond NEXAFS of Photoinduced Insulator-Metal Transition in VO2  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Femtosecond NEXAFS of Photoinduced Insulator-Metal Transition in VO2 Print Femtosecond NEXAFS of Photoinduced Insulator-Metal Transition in VO2 Print The grand goal motivating femtosecond studies of condensed-matter dynamics is to directly measure the structural pathways that connect different crystallographic, electronic, and magnetic phases of solids, as well as the short-lived transition states between reactants and products in chemical and biochemical reactions. Researchers from Berkeley Lab and the Université du Québec have taken a big step forward by adding femtosecond x-ray spectroscopy to the experimental toolkit with their first use of the laser-slicing technique to study the photoinduced metal-insulator phase transition in vanadium dioxide (VO2). Ultrafast X-Ray Science Only a moment's reflection is enough to confirm that the world around us is in constant flux. That change is everywhere and ever present yields the conclusion that extracting the full story requires time-resolved experiments in which one can trace in detail on the time scale on which atoms move the pathways (including transient intermediate states) by which matter changes from one form to another (phase transitions). For example, the making and breaking of chemical bonds and the rearrangement of atoms, which occur on the fundamental time scale of a vibrational period (about 100 femtoseconds), ultimately determine the course of phase transitions in solids, the kinetic pathways of chemical reactions, and even the efficiency and function of biological processes.

243

Characterization of metal oxide layers grown on CVD graphene  

SciTech Connect (OSTI)

Growth of a fully oxidized aluminum oxide layer with low surface roughness on graphene grown by chemical vapor deposition is demonstrated. This is accomplished by the deposition of a 0.2 nm thick titanium seed layer on the graphene prior to the deposition of the aluminum under ultra high vacuum conditions, which was subsequently oxidized. The stoichiometry and surface roughness of the oxide layers were measured for a range of titanium and aluminum depositions utilizing ex situ x-ray photoelectron spectrometry and atomic force microscopy. These fully oxidized films are expected to produce good dielectric layers for use in graphene based electronic devices.

Matsubayashi, Akitomo; Abel, Joseph; Prasad Sinha, Dhiraj; Lee, Ji Ung; LaBella, Vincent P. [College of Nanoscale Science and Engineering, University at Albany, SUNY, Albany, New York 12203 (United States)

2013-03-15T23:59:59.000Z

244

Synthesis, reactivity, and variable-temperature NMR studies of transition-metal complexes containing the 2,3-dihydrothiophene ligand  

SciTech Connect (OSTI)

The transition-metal complexes W(CO)5(2,3-DHT) (1), (Re(CO)5(2,3-DHT))SO3CF3 (3), PdCl2(2,3-DHT)2 (4), and Ru(CO)3Cl2(2,3-DHT) (5) containing S-bound 2,3-dihydrothiophene (2.3-DHT), a proposed intermediate in thiophene hydrodesulfurization, have been prepared and characterized. Variable-temperature H NMR studies of complexes 1, 3, and 5 establish that the barrier to inversion of the coordinated sulfur increases with the oxidation state of the metal: W(O) < Re(I) < Ru(II). In the series of W(CO)5(L) complexes, where L = 2,3-DHT, 2,5-DHT, and tetrahydrothiophene (THT), the inversion barriers decrease in the order 2,3-DHT (48.5 kJ/mol) > 2,5-DHT (45.6) > THT (43.9), which is also the order of decreasing ring strain in the sulfur ligands. Thus, the less strained the ligand, the more easily it achieves the planar transition state required for inversion. 30 references, 3 figures.

Sauer, N.N.; Angelici, R.J.

1987-07-01T23:59:59.000Z

245

Controlled incorporation of mid-to-high Z transition metals in CVD diamond  

SciTech Connect (OSTI)

We report on a general method to fabricate transition metal related defects in diamond. Controlled incorporation of Mo and W in synthetic CVD diamond was achieved by adding volatile metal precursors to the diamond chemical vapor deposition (CVD) growth process. Effects of deposition temperature, grain structure and precursor exposure on the doping level were systematically studied, and doping levels of up to 0.25 at.% have been achieved. The metal atoms are uniformly distributed throughout the diamond grains without any indication of inclusion formation. These results are discussed in context of the kinetically controlled growth process of CVD diamond.

Biener, M M; Biener, J; Kucheyev, S O; Wang, Y M; El-Dasher, B; Teslich, N E; Hamza, A V; Obloh, H; Mueller-Sebert, W; Wolfer, M; Fuchs, T; Grimm, M; Kriele, A; Wild, C

2010-01-08T23:59:59.000Z

246

Sharp semiconductor-to-metal transition of VO{sub 2} thin films on glass substrates  

SciTech Connect (OSTI)

Outstanding phase transition properties of vanadium dioxide (VO{sub 2}) thin films on amorphous glass were achieved and compared with the ones grown on c-cut sapphire and Si (111) substrates, all by pulsed laser deposition. The films on glass substrate exhibit a sharp semiconductor-to-metal transition (?4.3?°C) at a near bulk transition temperature of ?68.4?°C with an electrical resistance change as high as 3.2?×?10{sup 3} times. The excellent phase transition properties of the films on glass substrate are correlated with the large grain size and low defects density achieved. The phase transition properties of VO{sub 2} films on c-cut sapphire and Si (111) substrates were found to be limited by the high defect density.

Jian, Jie; Chen, Aiping [Department of Electrical and Computer Engineering, Texas A and M University, College Station, Texas 77843-3128 (United States); Zhang, Wenrui [Material Science and Engineering Program, Texas A and M University, College Station, Texas 77843-3128 (United States); Wang, Haiyan, E-mail: wangh@ece.tamu.edu [Department of Electrical and Computer Engineering, Texas A and M University, College Station, Texas 77843-3128 (United States); Material Science and Engineering Program, Texas A and M University, College Station, Texas 77843-3128 (United States)

2013-12-28T23:59:59.000Z

247

The structures of CO, NO and benzene on various transition metal surfaces: Overview of LEED (low-energy electron diffraction) and HREELS (high-resolution electron energy loss) results  

SciTech Connect (OSTI)

Recent results are summarized concerning the adsorption structures of carbon monoxide (CO) and nitric oxide (NO) chemisorbed on various transition metal surfaces, and of benzene (C6H6) on Pd, Rh and Pt(111). These results were for the most part obtained with intensity analysis of low-energy electron diffraction (LEED) and high-resolution electron energy loss spectroscopy (HREELS).

Ohtani, H.; Van Hove, M.A.; Somorjai, G.A.

1987-06-01T23:59:59.000Z

248

Catalytic proton reduction with transition metal complexes of the redox-active ligand bpy2PYMe  

E-Print Network [OSTI]

for a variety of earth abundant transition metal complexes in organic solvents2,3 as well as in aqueous media.4 of proton reduction catalysis by Co complexes have been performed in organic solvents utilizing strong acids Sciences, Bowling Green State University, Bowling Green, Ohio 43403, USA d Chemical Sciences Division

249

Mapping the Valence States of Transition-Metal Elements Using Energy-Filtered Transmission Electron Microscopy  

E-Print Network [OSTI]

spectrum of MnO2 acquired at 200 kV using a Hitachi HF-2000 transmission electron microscope equipped lines observed in electron energy-loss spectroscopy in a transmission electron microscope (TEMMapping the Valence States of Transition-Metal Elements Using Energy-Filtered Transmission Electron

Wang, Zhong L.

250

Journal of Crystal Growth 287 (2006) 402407 Transition metals in photovoltaic-grade ingot-cast multicrystalline  

E-Print Network [OSTI]

Journal of Crystal Growth 287 (2006) 402­407 Transition metals in photovoltaic-grade ingot silicon (mc-Si) ingot casting for cost-effective solar cell wafer production. Highly sensitive to the invited talk ``Transition metals in photovoltaic-grade multicrystalline silicon'' by A.A. Istratov, T

251

Comprehensive study of the metal-insulator transition in pulsed laser deposited epitaxial VO2 thin films  

E-Print Network [OSTI]

Comprehensive study of the metal-insulator transition in pulsed laser deposited epitaxial VO2 thin properties of high-quality VO2 thin films across its metal-insulator phase transition. Detailed x-ray deposition,9 sol-gel deriving,10 sputtering,11 and pulsed laser deposition,12 the study of VO2 is reviving

Wu, Junqiao

252

Vacancies and small vacancy clusters in BCC transition metals : calculation of binding energy, atomic relaxation and electronic  

E-Print Network [OSTI]

921 Vacancies and small vacancy clusters in BCC transition metals : calculation of binding energy(E) and gi(03C9), for vacancy-type lattice defects in BCC transition metals : The short-range repulsive energies between neighbouring atomic sites are simulated by a Born-Mayer potential. Binding energies of di-vacancies

Paris-Sud XI, Université de

253

Thermal resistance of contact with oxidized metal surfaces  

Science Journals Connector (OSTI)

A model of an elementary heat channel is analyzed which simulates the ... is derived which describes the increment of contact resistance due to the presence of an oxide...

V. M. Popov; A. I. Krasnoborod'ko

1973-10-01T23:59:59.000Z

254

Lattice site and thermal stability of transition metals in germanium  

E-Print Network [OSTI]

Although the first transistor was based on germanium, current chip technology mainly uses silicon due to its larger abundance, a lower price and higher quality silicon-oxide. However, a very important goal in microelectronics is to obtain faster integrated circuits. The advantages of germanium compared to silicon (e.g. a higher mobility of the charge carriers) motivates further research on germanium based materials. Semiconductor doping (e.g. introducing impurities into silicon and germanium in order to alter - and control - their properties) can be done by ion implantation or by in situ doping, whereby the host material is doped during growth. This thesis focuses on introducing dopants by ion implantation. The implantation as well as the subsequent measurements were performed in ISOLDE (CERN) using the emission channeling technique. Although ion implantation generates undesired defects in the host material (e.g. vacancies), such damage can be reduced by performing the implantation at an elevated temperature....

Augustyns, Valérie; Pereira, Lino

255

Plasmonic transparent conducting metal oxide nanoparticles and films for optical sensing applications  

DOE Patents [OSTI]

The disclosure relates to a method of detecting a change in a chemical composition by contacting a doped oxide material with a monitored stream, illuminating the doped oxide material with incident light, collecting exiting light, monitoring an optical signal based on a comparison of the incident light and the exiting light, and detecting a shift in the optical signal. The doped metal oxide has a carrier concentration of at least 10.sup.18/cm.sup.3, a bandgap of at least 2 eV, and an electronic conductivity of at least 10.sup.1 S/cm, where parameters are specified at a temperature of 25.degree. C. The optical response of the doped oxide materials results from the high carrier concentration of the doped metal oxide, and the resulting impact of changing gas atmospheres on that relatively high carrier concentration. These changes in effective carrier densities of conducting metal oxide nanoparticles are postulated to be responsible for the change in measured optical absorption associated with free carriers. Exemplary doped metal oxides include but are not limited to Al-doped ZnO, Sn-doped In.sub.2O.sub.3, Nb-doped TiO.sub.2, and F-doped SnO.sub.2.

Ohodnicki, Jr., Paul R; Wang, Congjun; Andio, Mark A

2014-01-28T23:59:59.000Z

256

Electronically conducting metal oxide nanoparticles and films for optical sensing applications  

DOE Patents [OSTI]

The disclosure relates to a method of detecting a change in a chemical composition by contacting a conducting oxide material with a monitored stream, illuminating the conducting oxide material with incident light, collecting exiting light, monitoring an optical signal based on a comparison of the incident light and the exiting light, and detecting a shift in the optical signal. The conducting metal oxide has a carrier concentration of at least 10.sup.17/cm.sup.3, a bandgap of at least 2 eV, and an electronic conductivity of at least 10.sup.-1 S/cm, where parameters are specified at the gas stream temperature. The optical response of the conducting oxide materials is proposed to result from the high carrier concentration and electronic conductivity of the conducting metal oxide, and the resulting impact of changing gas atmospheres on that relatively high carrier concentration and electronic conductivity. These changes in effective carrier densities and electronic conductivity of conducting metal oxide films and nanoparticles are postulated to be responsible for the change in measured optical absorption associated with free carriers. Exemplary conducting metal oxides include but are not limited to Al-doped ZnO, Sn-doped In.sub.2O.sub.3, Nb-doped TiO.sub.2, and F-doped SnO.sub.2.

Ohodnicki, Jr., Paul R.; Wang, Congjun; Andio, Mark A

2014-09-16T23:59:59.000Z

257

Halogen adsorption on transition-metal surfaces: A case study of Cl on Ta(110)  

Science Journals Connector (OSTI)

Through a series of ab initio calculations, we not only predict the atomic and electronic structure of Cl on Ta(110), but also provide a quantitative basis for understanding a number of controversial questions regarding halogen adsorption on transition-metal surfaces. We demonstrate that a simple dipole layer model accurately describes the unexpected decrease in the work function upon halogen absorption, and that our proposed overlayer structure explains the one-dimensional streaking in the low-energy electron-diffraction pattern of the adsorbate-covered surface. An analysis of the electronic structure suggests that transition metals such as Ta look like simple metals from the point of view of highly electronegative adsorbates such as Cl.

Christine J. Wu and John E. Klepeis

1997-04-15T23:59:59.000Z

258

Investigation of coal char-slag transition during oxidation: effect of temperature and residual carbon  

SciTech Connect (OSTI)

The transition of coal char to molten slag at high conversion was studied for a bituminous coal using a laminar entrained-flow reactor under oxidizing conditions. Post-oxidized char particles were analyzed by various techniques including loss-on-ignition, gas adsorption analysis, and scanning electron microscopy to determine carbon content, internal surface area and pore size distribution, and char morphology, respectively. These analyses provide information concerning the effect of temperature and residual carbon on the transition from porous char to molten slag. Results showed that, at temperatures above the ash flow temperature, the transition from porous char to molten slag occurred at about 90% conversion for the coal used in this study. No transition occurred at temperatures below the ash flow temperature. This finding explains previous observations that there is a coal-dependent critical carbon conversion at which the ash stickiness increases dramatically. This result also indicates that surface area can be used as a criterion for determining the critical conversion of the transition. In addition, it was found that the randomly overlapping pore model cannot be directly applied to predict the surface area evolution of char particles during the transition without considering the reopening of closed micropores during the initial reaction and the ash fusion effect. 33 refs., 9 figs., 2 tabs.

Suhui Li; Kevin J. Whitty [University of Utah, Salt Lake City, UT (United States). Institute for Clean and Secure Energy

2009-04-15T23:59:59.000Z

259

Method of nitriding, carburizing, or oxidizing refractory metal articles using microwaves  

DOE Patents [OSTI]

A method of nitriding an article of refractory-nitride-forming metal or metalloids. A consolidated metal or metalloid article is placed inside a microwave oven and nitrogen containing gas is introduced into the microwave oven. The metal or metalloid article is heated to a temperature sufficient to react the metal or metalloid with the nitrogen by applying a microwave energy within the microwave oven. The metal or metalloid article is maintained at that temperature for a period of time sufficient to convert the article of metal or metalloid to an article of refractory nitride. in addition, a method of applying a coating, such as a coating of an oxide, a carbide, or a carbo-nitride, to an article of metal or metalloid by microwave heating.

Holcombe, C.E.; Dykes, N.L.; Tiegs, T.N.

1992-10-13T23:59:59.000Z

260

Method of nitriding, carburizing, or oxidizing refractory metal articles using microwaves  

DOE Patents [OSTI]

A method of nitriding an article of refractory-nitride-forming metal or metalloids. A consolidated metal or metalloid article is placed inside a microwave oven and nitrogen containing gas is introduced into the microwave oven. The metal or metalloid article is heated to a temperature sufficient to react the metal or metalloid with the nitrogen by applying a microwave energy within the microwave oven. The metal or metalloid article is maintained at that temperature for a period of time sufficient to convert the article of metal or metalloid to an article of refractory nitride. in addition, a method of applying a coating, such as a coating of an oxide, a carbide, or a carbo-nitride, to an article of metal or metalloid by microwave heating.

Holcombe, Cressie E. (Knoxville, TN); Dykes, Norman L. (Oak Ridge, TN); Tiegs, Terry N. (Lenoir City, TN)

1992-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "transition metal oxide" 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

Bulk diffusion induced structural modifications of carbon-transition metal nanocomposite films  

SciTech Connect (OSTI)

The influence of transition metal (TM = V,Co,Cu) type on the bulk diffusion induced structural changes in carbon:TM nanocomposite films is investigated. The TMs have been incorporated into the carbon matrix via ion beam co-sputtering, and subsequently the films have been vacuum annealed in the temperature range of 300 - 700 deg. C. The structure of both the dispersed metal rich and the carbon matrix phases has been determined by a combination of elastic recoil detection analysis, x-ray diffraction, transmission electron microscopy, and Raman spectroscopy. The as-grown films consist of carbidic (V and Co) and metallic (Cu) nanoparticles dispersed in the carbon matrix. Thermal annealing induces surface segregation of Co and Cu starting at {>=} 500 deg. C, preceded by the carbide-metal transformation of Co-carbide nanoparticles at {approx} 300 deg. C. No considerable morphological changes occur in C:V films. In contrast to the surface diffusion dominated regime where all the metals enhance the six-fold ring clustering of C, in the bulk diffusion controlled regime only Co acts as a catalyst for the carbon graphitization. These results are consistent with the metal-induced crystallization mechanism in the C:Co films. The results are discussed on the basis of the metal-carbide phase stability, carbon solubility in metals or their carbides, and interface species.

Berndt, M.; Abrasonis, G.; Kovacs, Gy. J.; Krause, M.; Munnik, F.; Heller, R.; Kolitsch, A.; Moeller, W.

2011-03-15T23:59:59.000Z

262

CHEMISTRY OF SO{sub 2} ON MODEL METAL AND OXIDE CATALYSTS: PHOTOEMISSION AND XANES STUDIES  

SciTech Connect (OSTI)

High-resolution synchrotron based photoemission and x-ray absorption spectroscopy have been used to study the interaction of SO{sub 2} with a series of metals and oxides. The chemistry of SO{sub 2} on metal surfaces is rich. At low coverages, the molecule fully decomposes into atomic S and O. At large coverages, the formation of SO{sub 3} and SO{sub 4} takes place. The following sequence was found for the reactivity of the metals towards SO{sub 2}: Pt {approx} Rh < Ru < Mo << Zn, Sn, Cs. Alloying can be useful for reducing the chemical affinity of a metal for SO{sub 2} and controlling S poisoning. Pd atoms bonded to Rh and Pt atoms bonded to Sn interact weakly with SO{sub 2}. In general, SO{sub 2} mainly reacts with the O centers of metal oxides. SO{sub 4} is formed on CeO{sub 2} and SO{sub 3} on ZnO. On these systems there is no decomposition of SO{sub 2}. Dissociation of the molecule is observed after introducing a large amount of Ce{sup 3+} sites in ceria, or after depositing Cu or alkali metals on the oxide surfaces. These promote the catalytic activity of the oxides during the destruction of SO{sub 2}.

RODRIGUEZ,J.A.; JIRSAK,T.; CHATURVEDI,S.; HRBEK,J.; FREITAG,A.; LARESE,J.Z.

2000-07-09T23:59:59.000Z

263

Fabrication of superconducting metal-oxide textiles by heating impregnated polymeric material in a weakly oxidizing atmosphere  

SciTech Connect (OSTI)

A process is described for producing crystalline fibers, textiles or shapes comprised of YBa[sub 2]Cu[sub 3]O[sub 7[minus]x] where x varies from about 0 to about 0.4, said process comprising: (a) impregnating a preformed organic polymeric material with three metal compounds to provide metal elements in said material in substantially the atomic ratio occurring in said YBa[sub 2]Cu[sub 3]O[sub 7[minus]x]; (b) heating said impregnated material in a weakly oxidizing atmosphere containing from about 0.05% to about 2% oxygen by volume to a temperature sufficiently high to at least partially pyrolize and oxidize said organic material and at least partially oxidize said metal compounds substantially without ignition of said organic material and without formation of a molten phase or reaching a decomposition temperature of said YBa[sub 2]Cu[sub 3]O[sub 7[minus]x]; and (c) cooling the resulting material in at least a moderately oxidizing atmosphere to room temperature so as to obtain said fibers, textiles or shapes.

Van den Sype, J.S.

1993-07-13T23:59:59.000Z

264

Perspectives on the metallic interconnects for solid oxide fuel cells  

Science Journals Connector (OSTI)

The various stages and progress in the development of interconnect materials for solid oxide fuel cells (SOFCs) over the last two decades are reviewed. The criteria for the application of materials as intercon...

Wei-zhong Zhu; Mi Yan

2004-12-01T23:59:59.000Z

265

Electrostatic Cooperativity of Hydroxyl Groups at Metal Oxide...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Oxide Surfaces. Abstract: The O-H bond distribution of hydroxyl groups at the 110 goethite (R-FeOOH) surface was investigated by molecular dynamics. This distribution was...

266

The chemistry of transition metal complexes related to solar energy storage : H? production and small molecule (CO? and HX; X = Cl, Br) chemistry.  

E-Print Network [OSTI]

The studies in this thesis have focused on the chemistry of transition metal complexes related to solar energy storage: electrochemical H? production, HX splitting and CO? activation mediated by transition metal complexes. ...

Lee, Changhoon, Ph. D. Massachusetts Institute of Technology

2011-01-01T23:59:59.000Z

267

ALLOYING-DRIVEN PHASE STABILITY IN GROUP-VB TRANSITION METALS UNDER COMPRESSION  

SciTech Connect (OSTI)

The change in phase stability of Group-VB (V, Nb, and Ta) transition metals due to pressure and alloying is explored by means of first-principles electronic-structure calculations. It is shown that under compression stabilization or destabilization of the ground-state body-centered cubic (bcc) phase of the metal is mainly dictated by the band-structure energy that correlates well with the position of the Kohn anomaly in the transverse acoustic phonon mode. The predicted position of the Kohn anomaly in V, Nb, and Ta is found to be in a good agreement with data from the inelastic x-ray or neutron scattering measurements. In the case of alloying the change in phase stability is defined by the interplay between the band-structure and Madelung energies. We show that band-structure effects determine phase stability when a particular Group-VB metal is alloyed with its nearest neighbors within the same d-transition series: the neighbor with less and more d electrons destabilize and stabilize the bcc phase, respectively. When V is alloyed with neighbors of a higher (4d- or 5d-) transition series, both electrostatic Madelung and band-structure energies stabilize the body-centered-cubic phase. The opposite effect (destabilization) happens when Nb or Ta is alloyed with neighbors of the 3d-transition series.

Landa, A; Soderlind, P

2011-04-11T23:59:59.000Z

268

Metallic magnetism and change of conductivity in the nano to bulk transition of cobalt ferrite  

SciTech Connect (OSTI)

Variations in conductivity with particle size have been observed in cobalt ferrite, when synthesized by solgel auto-combustion method. Impedance analysis reveals metallic and semiconducting behavior at room temperature for a particle size of 6?nm and 52?nm, respectively. Upon thermal activation, metallic to semiconducting phase transition has been observed as a function of particle size and vice-versa. Grainboundary Resistance (R{sub gb}), increased drastically with particle size (19?M? for 6?nm and 259?M? for 52?nm) at room temperature. AC conductivity and dielectric constants exhibit similar metallic to semiconducting phase transition at 6?nm and semiconducting behavior at 52?nm with temperature in the selected frequencies. Enhanced magnetic moment with an increase in the grain size along with decreased coercivity (1444?G to 1146?G) reveals transition from single domain to multi-domain. Increased inter-particle interaction is responsible for metallicity at the nano level and on the contrary semiconductivity is attributed to bulk.

Arunkumar, A.; Vanidha, D.; Kannan, R., E-mail: kannan@pec.edu [Department of Physics, Pondicherry Engineering College, Puducherry–605 014 (India); Oudayakumar, K. [Department of Physics, Sri Manakula Vinayagar Engineering College, Puducherry–605 107 (India); Rajagopan, S. [Department of Chemistry, Pondicherry Engineering College, Puducherry–605 014 (India)

2013-11-14T23:59:59.000Z

269

Formation and distribution of neutral vanadium, niobium, and tantalum oxide clusters: Single photon ionization at 26.5 eV  

E-Print Network [OSTI]

. INTRODUCTION Transition metals, as well as their oxides, carbides, ni- trides, and sulfides, are unique bonds at a surface.1 Transition metal oxides are employed extensively as catalysts in the chemical. During the ionization process the metal oxide clusters are almost free of fragmentation. The most stable

Rocca, Jorge J.

270

Structure, adhesion, and stability of metal/oxide and oxide/oxide interfaces. Technical progress report, August 1, 1992--July 31, 1993  

SciTech Connect (OSTI)

Studies of structural, electronic, and chemical properties of metal/oxide and oxide/oxide interfaces were performed on well-defined interfaces that created by depositing ultra-thin potassium and aluminum films and their oxides onto single crystal TiO{sub 2} and NiO surfaces. Work focused on determining the structure, growth mechanisms, and morphologies of metal and oxide films as they are deposited an single crystal oxide surfaces using RHEED and atomic force microscopy probing electronic structure, bonding and chemical interactions at the interfaces using x-ray and uv photoelectron spectroscopies (XPS, UPS) and Auger electron spectroscopy (AES), and understanding factors affecting stability and reactivity of the interface regions including the role of defects and impurities. Results indicate that kinetic effects have an important influence on interface structure and composition, and they also show that defects in the oxide substrate induce new electronic states at the interface which play a major role in cation-anion bonding and interface interactions. The results establish a link between electronic and chemical bonding properties and the interface structure and morphology, which is required to successfully manipulate the interfacial properties of advanced ceramic materials.

Lad, R.J.

1992-11-01T23:59:59.000Z

271

Mesoporous metal oxide microsphere electrode compositions and their methods of making  

SciTech Connect (OSTI)

Compositions and methods of making are provided for treated mesoporous metal oxide microspheres electrodes. The compositions comprise (a) microspheres with an average diameter between 200 nanometers (nm) and 10 micrometers (.mu.m); (b) mesopores on the surface and interior of the microspheres, wherein the mesopores have an average diameter between 1 nm and 50 nm and the microspheres have a surface area between 50 m.sup.2/g and 500 m.sup.2/g, and wherein the composition has an electrical conductivity of at least 1.times.10.sup.-7 S/cm at 25.degree. C. and 60 MPa. The methods of making comprise forming a mesoporous metal oxide microsphere composition and treating the mesoporous metal oxide microspheres by at least one method selected from the group consisting of: (i) annealing in a reducing atmosphere, (ii) doping with an aliovalent element, and (iii) coating with a coating composition.

Parans Paranthaman, Mariappan; Bi, Zhonghe; Bridges, Craig A; Brown, Gilbert M

2014-12-16T23:59:59.000Z

272

Book Review of Mössbauer Spectroscopy and Transition Metal Chemistry: Fundamentals and Applications  

Science Journals Connector (OSTI)

Book Review of Mössbauer Spectroscopy and Transition Metal Chemistry: Fundamentals and Applications ... The first four chapters cover the fundamentals of Mössbauer spectroscopy, from its discovery in 1958 through the first observation of hyperfine interactions to the use of these interactions to better understand a compound’s electronic and magnetic properties. ... The examples of iron-57 Mössbauer spectroscopy found in Chapter 8 are largely limited to the excellent work of the authors on electronic spin-state transitions, unusual spin and valence states, and applications to earth and space science. ...

Fernande Grandjean

2011-11-14T23:59:59.000Z

273

Ag and Au atoms intercalated in bilayer heterostructures of transition metal dichalcogenides and graphene  

SciTech Connect (OSTI)

The diffusive motion of metal nanoparticles Au and Ag on monolayer and between bilayer heterostructures of transition metal dichalcogenides and graphene are investigated in the framework of density functional theory. We found that the minimum energy barriers for diffusion and the possibility of cluster formation depend strongly on both the type of nanoparticle and the type of monolayers and bilayers. Moreover, the tendency to form clusters of Ag and Au can be tuned by creating various bilayers. Tunability of the diffusion characteristics of adatoms in van der Waals heterostructures holds promise for controllable growth of nanostructures.

Iyikanat, F., E-mail: fadiliyikanat@iyte.edu.tr; Senger, R. T. [Department of Physics, Izmir Institute of Technology, 35430 Izmir (Turkey); Sahin, H., E-mail: hasan.sahin@uantwerpen.be; Peeters, F. M. [Department of Physics, University of Antwerp, 2610 Antwerp (Belgium)

2014-09-01T23:59:59.000Z

274

The near-edge structure in energy-loss spectroscopy: many-electron and magnetic effects in transition metal nitrides and carbides  

E-Print Network [OSTI]

in transition metal nitrides and carbides This article has been downloaded from IOPscience. Please scroll down-loss spectroscopy: many-electron and magnetic effects in transition metal nitrides and carbides A T Paxton, M van energies are systematically overestimated by 4.22 ± 0.44 eV in twelve transition metal carbides

Paxton, Anthony T.

275

Electronic structure of the 4d transition metal carbides: Dispersed fluorescence spectroscopy of MoC, RuC, and PdC  

E-Print Network [OSTI]

Electronic structure of the 4d transition metal carbides: Dispersed fluorescence spectroscopy of Mo transition metal carbides is also provided. © 2001 American Institute of Physics. DOI: 10.1063/1.1316042 I, and astrochemistry. Within the 4d se- ries, the diatomic transition metal carbides have aroused considerable interest

Morse, Michael D.

276

Determination of Interfacial Adhesion Strength between Oxide Scale and Substrate for Metallic SOFC Interconnects  

SciTech Connect (OSTI)

The interfacial adhesion strength between the oxide scale and the substrate is crucial to the reliability and durability of metallic interconnects in SOFC operating environments. It is necessary, therefore, to establish a methodology to quantify the interfacial adhesion strength between the oxide scale and the metallic interconnect substrate, and furthermore to design and optimize the interconnect material as well as the coating materials to meet the design life of an SOFC system. In this paper, we present an integrated experimental/analytical methodology for quantifying the interfacial adhesion strength between oxide scale and a ferritic stainless steel interconnect. Stair-stepping indentation tests are used in conjunction with subsequent finite element analyses to predict the interfacial strength between the oxide scale and Crofer 22 APU substrate.

Sun, Xin; Liu, Wenning N.; Stephens, Elizabeth V.; Khaleel, Mohammad A.

2008-01-21T23:59:59.000Z

277

Metal oxide coating on first mirror in fusion reactor with carbon wall  

Science Journals Connector (OSTI)

Abstract The lifetime of diagnostic equipment in a fusion reactor is typically very short. The first mirror used to reflect optical signals for diagnostics plays a crucial role in the reactor, and it is highly important to develop a more durable first mirror which can survive in the hostile environment. In this work, by conducting electron beam deposition on molybdenum substrates, metallic oxide mirrors are prepared and studied in the simulated environment. The multi-layered metal oxide mirror exhibits much higher reflectivity than the original molybdenum one and the in situ technique to monitor the performance of the first mirror is developed and described.

Xirui Hou; Zhengwei Wu; Paul K. Chu

2014-01-01T23:59:59.000Z

278

Chemicl-looping combustion of coal with metal oxide oxygen carriers  

SciTech Connect (OSTI)

The combustion and reoxidation properties of direct coal chemical-looping combustion (CLC) over CuO, Fe2O3, Co3O4, NiO, and Mn2O3 were investigated using thermogravimetric analysis (TGA) and bench-scale fixed-bed flow reactor studies. When coal is heated in either nitrogen or carbon dioxide (CO2), 50% of weight loss was observed because of partial pyrolysis, consistent with the proximate analysis. Among various metal oxides evaluated, CuO showed the best reaction properties: CuO can initiate the reduction reaction as low as 500 °C and complete the full combustion at 700 °C. In addition, the reduced copper can be fully reoxidized by air at 700 °C. The combustion products formed during the CLC reaction of the coal/metal oxide mixture are CO2 and water, while no carbon monoxide was observed. Multicycle TGA tests and bench-scale fixed-bed flow reactor tests strongly supported the feasibility of CLC of coal by using CuO as an oxygen carrier. Scanning electron microscopy (SEM) images of solid reaction products indicated some changes in the surface morphology of a CuO-coal sample after reduction/oxidation reactions at 800 °C. However, significant surface sintering was not observed. The interactions of fly ash with metal oxides were investigated by X-ray diffraction and thermodynamic analysis. Overall, the results indicated that it is feasible to develop CLC with coal by metal oxides as oxygen carriers.

Siriwardane, R.; Tian, H.; Richards, G.; Simonyi, T.; Poston, J.

2009-01-01T23:59:59.000Z

279

Metallization of Fluid Nitrogen and the Mott Transition in Highly Compressed Low-Z Fluids  

Science Journals Connector (OSTI)

Electrical conductivities are reported for degenerate fluid nitrogen at pressures up to 180 GPa (1.8 Mbar) and temperatures of ?7000??K. These extreme quasi-isentropic conditions were achieved with multiple-shock compression generated with a two-stage light-gas gun. Nitrogen undergoes a nonmetal-metal transition at 120 GPa, probably in the monatomic state. These N data and previous conductivity data for H, O, Cs, and Rb are used to develop a general picture of the systematics of the nonmetal-metal transition in these fluids. Specifically, the density dependences of electrical conductivities in the semiconducting fluid are well correlated with the radial extent of the electronic charge-density distributions of H, N, O, Cs, and Rb atoms. These new data for N scale with previous data for O, as expected from their similar charge-density distributions.

R. Chau, A. C. Mitchell, R. W. Minich, and W. J. Nellis

2003-06-18T23:59:59.000Z

280

Ab initio calculation of the tetragonal shear moduli of the cubic transition metals  

Science Journals Connector (OSTI)

A new approach for ground-state-energy calculations, based on the density-functional formalism, is proposed. It enables us to express a shear modulus as a sum of two simple terms, a one-electron "band term," based on a "frozen-potential" condition, and a "Madelung term" based on an effective ionic charge. This method is applied for the tetragonal shear moduli of the thirteen nonferromagnetic cubic transition metals, using the linear muffin-tin orbital—atomic sphere approximation band method. The results agree fairly well with experiment. To our knowledge, this is the first successful ab initio calculation of shear moduli in transition metals, and the results for Rh preceded the experimental measurement.

M. Dacorogna; J. Ashkenazi; M. Peter

1982-08-15T23:59:59.000Z

Note: This page contains sample records for the topic "transition metal oxide" 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 interactions in nonreactive coadsorption: H/sub 2/ and CO on transition-metal surfaces  

SciTech Connect (OSTI)

A short overview is given of the nonreactive coadsorption of hydrogen and carbon monoxide on transition metals with particular attention given to Ni(100) single-crystal surfaces where complex interactions are noted. Data derived from several complimentary surface science techniques are presented. Different organizations of the coadsorbed species are found on different crystal faces emphasizing structure sensitivity. The relation between these results and catalytic processes is noted.

White, J.M.

1983-03-17T23:59:59.000Z

282

Full-potential calculations using the generalized gradient approximation: Structural properties of transition metals  

Science Journals Connector (OSTI)

The equilibrium volumes and bulk moduli of nonmagnetic 3d, 4d, and 5d transition metals have been calculated using a full-potential linear-muffin-tin-orbitals (FP-LMTO) method and the generalized gradient approximation (PW91) of Perdew and Wang [in Electronic Structure of Solids 1991, edited by P. Ziesche and H. Eschrig (Akademie Verlag, Berlin, 1991), Vol. 11]. The gradient-corrected FP-LMTO results are found to be superior to the corresponding local-density approximation (LDA) results in all transition-metal series. Furthermore, the atomic-spheres approximation (ASA) is found to yield larger equilibrium volumes and smaller bulk moduli than the FP method. The inaccuracies introduced by the ASA are of the same magnitude as the gradient corrections, suggesting that a FP treatment is important for gradient-corrected calculations. Excellent agreement with experiment is found for the c/a ratios of the hcp metals using both the LDA and the PW91, while for the fcc-bcc structural energy differences of 4d metals disagreement with semiempirical estimates remains.

V. Ozoli?š and M. Körling

1993-12-15T23:59:59.000Z

283

Metal oxide/organic interface investigations for photovoltaic devices  

E-Print Network [OSTI]

summarises work I have carried out as a PhD student of the Optoelectronics Group at Cavendish Laboratory of the University of Cambridge since October 2010. I am thankful to the Engineering and Physical Sciences Research Council and the A.G. Leventis... are often used in many other optoelectronic devices such as photovoltaics and light emitting diodes. Sufficiently conducting oxides with the appropriate electron affinities and ionisation potentials, can be employed as charge transport and injection layers...

Pachoumi, Olympia

2014-10-07T23:59:59.000Z

284

Gas-phase ion/ion reactions of transition metal complex cations with multiply charged oligodeoxynucleotide anions  

Science Journals Connector (OSTI)

Multiply deprotonated hexadeoxyadenylate anions, (A6?nH)n?, where n...=3–5, have been subjected to reaction with a range of divalent transition-metal complex cations in the gas phase. The cations studied included...

Christopher K. Barlow; Brittany D. M. Hodges…

2008-02-01T23:59:59.000Z

285

Selective separation of some ecotoxic transition metal ions from aqueous solutions using immobilized macrocyclic material containing solid phase extraction system  

Science Journals Connector (OSTI)

A simple flow-based method was developed for the simultaneous separation of certain transition metal ions (Co, Ni, Cu, Zn, Cd) from aqueous systems, which ions show ecotoxic effects when present at elevated ... (...

Ismail M. M. Rahman; Yoshiaki Furusho…

2011-12-01T23:59:59.000Z

286

Composition-Tailored Synthesis of Gradient Transition Metal Precursor Particles for Lithium-Ion Battery Cathode Materials  

Science Journals Connector (OSTI)

Composition-Tailored Synthesis of Gradient Transition Metal Precursor Particles for Lithium-Ion Battery Cathode Materials ... Collected particles were lithiated, and one promising material was evaluated as the active cathode component in a lithium-ion battery. ...

Gary M. Koenig, Jr.; Ilias Belharouak; Haixai Deng; Yang-Kook Sun; Khalil Amine

2011-03-09T23:59:59.000Z

287

Ab initio study of structural stability of small 3d late transition metal clusters: Interplay of magnetization and hybridization  

E-Print Network [OSTI]

Using first-principles density-functional-theory–based calculations, we analyze the structural stability of small clusters of 3d late transition metals. We consider the relative stability of the two structures: layer-like ...

Datta, Soumendu

288

Criteria for Preparing and Packaging Plutonium Metals and Oxides for Long-Term Storage  

SciTech Connect (OSTI)

This Standard provides criteria for packaging of plutonium metals and stabilized oxides for storage periods of at least 50 years. To meet the criteria, plutonium-bearing materials must be in stable forms and be packaged in containers designed to maintain their integrity both under normal storage conditions and during anticipated handling accidents.

NONE

1994-12-01T23:59:59.000Z

289

Nanotube Formation: Researchers Learn To Control The Dimensions Of Metal Oxide Nanotubes  

E-Print Network [OSTI]

Nanotube Formation: Researchers Learn To Control The Dimensions Of Metal Oxide Nanotubes ScienceDaily (Aug. 29, 2007) -- Moving beyond carbon nanotubes, researchers are developing insights-walled inorganic nanotubes could be useful in a range of nanotechnology applications that require precise control

Nair, Sankar

290

Evaluation of Novel Ceria-Supported Metal Oxides As Oxygen Carriers for Chemical-Looping Combustion  

E-Print Network [OSTI]

Evaluation of Novel Ceria-Supported Metal Oxides As Oxygen Carriers for Chemical-Looping Combustion and examined as oxygen carrier materials for chemical-looping combustion (CLC). Unlike conventional support agglomeration. 1. INTRODUCTION 1.1. Chemical-Looping Combustion. Chemical-looping combustion (CLC

Azad, Abdul-Majeed

291

Self-assembly of oxide-supported metal clusters into ring-like Kristoffer Meinander,  

E-Print Network [OSTI]

Self-assembly of oxide-supported metal clusters into ring-like structures Kristoffer Meinander, Kai, Finland Abstract Self-assembly is a phenomenon that continuously occurs at the nanoscale, as atoms form of these organized systems, but the precise mechanism, with which this self-assembly progresses, is seldom known

Nordlund, Kai

292

Electrochromic nickel oxide simultaneously doped with lithium and a metal dopant  

DOE Patents [OSTI]

An electrochromic device comprising a counter electrode layer comprised of lithium metal oxide which provides a high transmission in the fully intercalated state and which is capable of long-term stability, is disclosed. Methods of making an electrochromic device comprising such a counter electrode are also disclosed.

Gillaspie, Dane T; Weir, Douglas G

2014-04-01T23:59:59.000Z

293

AC conductivity of nanoporous metal-oxide photoanodes for solar energy conversion  

E-Print Network [OSTI]

AC conductivity of nanoporous metal-oxide photoanodes for solar energy conversion Steven J. Konezny% solar-to-electric energy conversion efficiency) exploited the large surface area of nanoporous thin of nanoporous thin films without increasing the recombination rate. To ensure efficient charge carrier

Konezny, Steven J.

294

High density adsorbed oxygen on Rh,,111... and enhanced routes to metallic oxidation using atomic oxygen  

E-Print Network [OSTI]

High density adsorbed oxygen on Rh,,111... and enhanced routes to metallic oxidation using atomic oxygen K. D. Gibson, Mark Viste, Errol C. Sanchez, and S. J. Sibener The James Franck Institute; accepted 30 November 1998 Exposure of Rh 111 to atomic oxygen leads to the facile formation of a full

Sibener, Steven

295

Surfactant Organic Molecules Restore Magnetism in Metal-Oxide Nanoparticle Surfaces  

E-Print Network [OSTI]

Surfactant Organic Molecules Restore Magnetism in Metal-Oxide Nanoparticle Surfaces Juan Salafranca, Nashville, Tennessee 37235, United States *S Supporting Information ABSTRACT: The properties of magnetic nanoparticles tend to be depressed by the unavoidable presence of a magnetically inactive surface layer. However

Pennycook, Steve

296

Structural transition in rare earth doped zirconium oxide: A positron annihilation study  

SciTech Connect (OSTI)

Graphical abstract: New microstructural analysis and phase transition of rare earth doped mixed oxide compounds such as: Sm{sub 2?x}Dy{sub x}Zr{sub 2}O{sub 7} (where x = 0.0 ? x ? 2.0) that are potentially useful as solid oxide fuels, ionic conductors, optoelectronic materials and most importantly as radiation resistant host for high level rad-waste disposal, structural transition in the system is reported through positron annihilation spectroscopy as there is an indication in the X-ray diffraction analysis. Highlights: ? Zirconium oxide material doped with rare earth ions. ? The method of positron annihilation spectroscopy suggests a phase transition in the system. ? The crystal structure transformation from pure pyrochlore to defect fluorite type of structure is shown by X-ray diffraction results. -- Abstract: A series of compounds with the general composition Sm{sub 2?x}Dy{sub x}Zr{sub 2}O{sub 7} (where 0 ? x ? 2.0) were synthesized by chemical route and characterized by powder X-ray diffraction (XRD) analysis. The rare earth ion namely Sm{sup +3} in the compound was gradually replaced with another smaller and heavier ion, Dy{sup +3} of the 4f series, there by resulting in order–disorder structural transition, which has been studied by positron annihilation lifetime and Doppler broadening spectroscopy. This study reveals the subtle electronic micro environmental changes in the pyrochlore lattice (prevalent due to the oxygen vacancy in anti-site defect structure of the compound) toward its transformation to defect fluorite structure as found in Dy{sub 2}Zr{sub 2}O{sub 7}. A comparison of the changes perceived with PAS as compared to XRD analysis is critically assayed.

Chakraborty, Keka [Applied Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India)] [Applied Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Bisoi, Abhijit [Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064 (India)] [Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064 (India); Ganguly, Bichitra Nandi, E-mail: bichitra.ganguly@saha.ac.in [Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064 (India); Grover, Vinita; Sayed, Farheen Nasir; Tyagi, A.K. [Applied Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India)] [Applied Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India)

2012-11-15T23:59:59.000Z

297

Metal-Insulator Transition Revisited for Cold Atoms in Non-Abelian Gauge Potentials  

E-Print Network [OSTI]

We discuss the possibility of realizing metal-insulator transitions with ultracold atoms in two-dimensional optical lattices in the presence of artificial gauge potentials. Such transitions have been extensively studied for magnetic fields corresponding to Abelian gauges; they occur when the magnetic flux penetrating the lattice plaquette is an irrational multiple of the magnetic flux quantum. Here we present the first study of these transitions for non-Abelian U(2) gauge fields, which can be realized with atoms with two pairs of degenerate internal states. In contrast to the Abelian case, the spectrum and localization transition in the non-Abelian case is strongly influenced by atomic momenta. In addition to determining the localization boundary, the momentum fragments the spectrum and the minimum energy viewed as a function of momentum exhibits a step structure. Other key characteristics of the non-Abelian case include the absence of localization for certain states and satellite fringes around the Bragg peaks in the momentum distribution and an interesting possibility that the transition can be tuned by the atomic momenta.

Indubala I. Satija; Daniel C. Dakin; Charles W. Clark

2006-07-10T23:59:59.000Z

298

Electrospun and oxidized cellulose materials for environmental remediation of heavy metals in groundwater  

SciTech Connect (OSTI)

This chapter focuses on the use of modified cellulosic materials in the field of environmental remediation. Two different chemical methods were involved in fabricating oxidized cellulose (OC), which has shown promise as a metal ion chelator in environmental applications. Electrospinning was utilized to introduce a more porous structure into an oxidized cellulose matrix. FTIR and Raman spectroscopy were used to study both the formation of OC and its surface complexation with metal ions. IR and Raman spectroscopic data demonstrate the formation of characteristic carboxylic groups in the structure of the final products and the successful formation of OC-metal complexes. Subsequent field tests at the Field Research Site at Oak Ridge National Laboratory confirmed the value of OC for sorption of both U and Th ions.

Han, Dong [Stony Brook University (SUNY); Halada, Gary P. [Stony Brook University (SUNY); Spalding, Brian Patrick [ORNL; Brooks, Scott C [ORNL

2009-12-01T23:59:59.000Z

299

ESS 2012 Peer Review - Architectural Diversity of Metal Oxide Nanostructures - Esther Takeuchi, Stony Brook University  

Broader source: Energy.gov (indexed) [DOE]

Architectural Diversity of Metal Oxide Nanostructures: Architectural Diversity of Metal Oxide Nanostructures: An Opportunity for the Rational Optimization of Group II Cation Based Batteries. Esther S. Takeuchi, Kenneth J. Takeuchi, Amy C. Marschilok esther.takeuchi@stonybrook.edu, kenneth.takeuchi.1@stonybrook.edu, amy.marschilok@stonybrook.edu Utilize earth abundant, low cost elements with minimal environmental impact as battery materials. Exploit magnesium due to air stability and ~1,000X higher natural abundance than lithium and ~5,000X higher abundance than lead. Cathode materials feature Mn, Fe or V metal centers. Strategy Results Results This project targets some of the unique needs of large scale power storage: 1) reduced cost 2) low environmental impact 3) scalability 4) reversibility

300

Experimental and Theoretical Studies on the Reaction of H2 with NiO: Role of O Vacancies and Mechanism for Oxide  

E-Print Network [OSTI]

, metal oxides are also used as supports of many other catalytic materials (metals, sulfides, carbides are poorly understood in most situations.7 Among the transition-metal oxides, the reduction of H2. I. Introduction Metal oxides are used as catalysts in a large variety of commercial processes

Frenkel, Anatoly

Note: This page contains sample records for the topic "transition metal oxide" 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.


301

Evaluation of reaction mechanism of coal-metal oxide interactions in chemical-looping combustion  

SciTech Connect (OSTI)

The knowledge of reaction mechanism is very important in designing reactors for chemical-looping combustion (CLC) of coal. Recent CLC studies have considered the more technically difficult problem of reactions between abundant solid fuels (i.e. coal and waste streams) and solid metal oxides. A definitive reaction mechanism has not been reported for CLC reaction of solid fuels. It has often been assumed that the solid/solid reaction is slow and therefore requires that reactions be conducted at temperatures high enough to gasify the solid fuel, or decompose the metal oxide. In contrast, data presented in this paper demonstrates that solid/solid reactions can be completed at much lower temperatures, with rates that are technically useful as long as adequate fuel/metal oxide contact is achieved. Density functional theory (DFT) simulations as well as experimental techniques such as thermo-gravimetric analysis (TGA), flow reactor studies, in situ X-ray photo electron spectroscopy (XPS), in situ X-ray diffraction (XRD) and scanning electron microscopy (SEM) are used to evaluate how the proximal interaction between solid phases proceeds. The data indicate that carbon induces the Cu-O bond breaking process to initiate the combustion of carbon at temperatures significantly lower than the spontaneous decomposition temperature of CuO, and the type of reducing medium in the vicinity of the metal oxide influences the temperature at which the oxygen release from the metal oxide takes place. Surface melting of Cu and wetting of carbon may contribute to the solid-solid contacts necessary for the reaction. (author)

Siriwardane, Ranjani; Richards, George; Poston, James [US Department of Energy, National Energy Technology Laboratory, 3610 Collins Ferry Road, P.O. Box 880, Morgantown, WV 26507-0880 (United States); Tian, Hanjing; Miller, Duane; Simonyi, Thomas [US Department of Energy, National Energy Technology Laboratory, 3610 Collins Ferry Road, P.O. Box 880, Morgantown, WV 26507-0880 (United States); URS, 3610 Collins Ferry Road, Morgantown, WV 26505 (United States)

2010-11-15T23:59:59.000Z

302

Metal oxide catalysts for the low temperature selective oxidation of propane to iso-propanol.  

E-Print Network [OSTI]

??A range of Ga203/Mo03 and C03O4 catalysts have been prepared and tested for the oxidative dehydrogenation of propane to propene. The Ga2(VMo03 physical mixture demonstrated… (more)

Davies, Thomas Edward.

2006-01-01T23:59:59.000Z

303

Abstract No. pan0505 Sorption of Heavy Metal Contaminants onto Hydrated Ferric Oxides: Mechanistic Modeling using X-ray  

E-Print Network [OSTI]

Abstract No. pan0505 Sorption of Heavy Metal Contaminants onto Hydrated Ferric Oxides: Mechanistic. Hence, to understand the mobility and bioavailability of these metal contaminants, these sorption suggesting that sorption of these metal ions onto ferrihydrite can be described by one average type of site

Sparks, Donald L.

304

The Velocity of Oxidation of the Metals and the Structure of Coloured Oxide Films  

Science Journals Connector (OSTI)

... The simplest explanation of these facts would appear to be that the treatment causes a roughening of the surface, whereby the effective area of the metal is increased. If this ...

D. H. BANGHAM; J. STAFFORD

1925-01-17T23:59:59.000Z

305

Method of making a catalytic metal oxide selective for the conversion of a gas and a coating system for the selective oxidation of hydrocarbons and carbon monoxide  

SciTech Connect (OSTI)

A method is described of making a catalytic metal oxide selective to catalyzing the conversion of given gas species, comprising: intimately supporting a solid film of catalytic metal oxide on an electrically conducting material, said film having an exposed outer surface spaced no greater than 1,000 angstroms from said conducting material and said conducting material being matched to the composition of said oxide to change the electron state of the exposed outer surface to promote a reaction between given gas species and said oxide, said metal oxide being selected from the group consisting of TiO[sub 2], SnO[sub 2], FeO, SrTiO[sub 3], and CoO, and said conducting material being selected from the group consisting of Au, Pt, TiN, Pd, Rh, Ni, and Co.

Logothetis, E.M.; Soltis, R.E.

1993-07-20T23:59:59.000Z

306

Direct Observation of Decoupled Structural and Electronic Transitions and an Ambient Pressure Monocliniclike Metallic Phase of VO2  

Science Journals Connector (OSTI)

We report the simultaneous measurement of the structural and electronic components of the metal-insulator transition (MIT) of VO2 using electron and photoelectron spectroscopies and microscopies. We show that these evolve over different temperature scales, and are separated by an unusual monocliniclike metallic phase. Our results provide conclusive evidence that the new monocliniclike metallic phase, recently identified in high-pressure and nonequilibrium measurements, is accessible in the thermodynamic transition at ambient pressure, and we discuss the implications of these observations on the nature of the MIT in VO2.

J. Laverock; S. Kittiwatanakul; A.?A. Zakharov; Y.?R. Niu; B. Chen; S.?A. Wolf; J.?W. Lu; K.?E. Smith

2014-11-17T23:59:59.000Z

307

Chemical-looping combustion of coal with metal oxide oxygen carriers  

SciTech Connect (OSTI)

The combustion and reoxidation properties of direct coal chemical-looping combustion (CLC) over CuO, Fe{sub 2}O{sub 3}, CO{sub 3}O{sub 4}, NiO, and Mn{sub 2}O{sub 3} were investigated using thermogravimetric analysis (TGA) and bench-scale fixed-bed flow reactor studies. When coal is heated in either nitrogen or carbon dioxide (CO{sub 2}), 50% of weight loss was observed because of partial pyrolysis, consistent with the proximate analysis. Among various metal oxides evaluated, CuO showed the best reaction properties: CuO can initiate the reduction reaction as low as 500{sup o}C and complete the full combustion at 700{sup o}C. In addition, the reduced copper can be fully reoxidized by air at 700{sup o}C. The combustion products formed during the CLC reaction of the coal/metal oxide mixture are CO{sub 2} and water, while no carbon monoxide was observed. Multicycle TGA tests and bench-scale fixed-bed flow reactor tests strongly supported the feasibility of CLC of coal by using CuO as an oxygen carrier. Scanning electron microscopy (SEM) images of solid reaction products indicated some changes in the surface morphology of a CuO-coal sample after reduction/oxidation reactions at 800 {sup o}C. However, significant surface sintering was not observed. The interactions of fly ash with metal oxides were investigated by X-ray diffraction and thermodynamic analysis. Overall, the results indicated that it is feasible to develop CLC with coal by metal oxides as oxygen carriers. 22 refs., 12 figs., 2 tabs.

Ranjani Siriwardane; Hanjing Tian; George Richards; Thomas Simonyi; James Poston [United States Department of Energy, Morgantown, WN (United States). National Energy Technology Laboratory

2009-08-15T23:59:59.000Z

308

Effect of the Support on the Electronic Structure of Au Nanoparticles Supported on Transition Metal Carbides: Choice of the Best Substrate for Au Activation  

SciTech Connect (OSTI)

Periodic density functional theory calculations on large supercells have been carried out to investigate the atomic and electronic structure of small gold particles (Au{sub 2}, Au{sub 4}, Au{sub 9}, Au{sub 13}, and Au{sub 14}) supported on the (001) surface of various transition metal carbides (TiC, ZrC, VC, and {delta}-MoC). All the supported Au particles exhibited strong interactions with the C sites of the metal-carbide surfaces. Nevertheless, the interactions between adsorbed Au atoms were attractive, thus ultimately facilitating nucleation of two- or three-dimensional metal particles. The presence of the underlying carbide strongly modified the electronic structure and charge density of the supported metal particles resulting in the experimentally proven improved catalytic performance of the resulting systems as compared with cases where the support is an oxide. The electronic perturbations were quite strong for two-dimensional gold particles directly in contact with the carbide substrates and gradually decreased for two-layer and three-layer thick supported particles. While all the metal carbides examined induced a qualitatively similar perturbation on the supported Au particles, the effect is significantly larger for ZrC thus suggesting that the resulting model catalyst would perform even better than the already tried Au/TiC system.

Rodriguez, J.A.; Florez, E.; Feria, L.; Viñes, F.; Illas, F.

2009-10-16T23:59:59.000Z

309

Effect of the Support on the Electronic Structure of Au Nanoparticles Supported on Transition Metal Carbides: Choice of the Best Substrate for Au Activation  

SciTech Connect (OSTI)

Periodic density functional theory calculations on large supercells have been carried out to investigate the atomic and electronic structure of small gold particles (Au{sub 2}, Au{sub 4}, Au{sub 9}, Au{sub 13}, and Au{sub 14}) supported on the (001) surface of various transition metal carbides (TiC, ZrC, VC, and {delta}-MoC). All the supported Au particles exhibited strong interactions with the C sites of the metal-carbide surfaces. Nevertheless, the interactions between adsorbed Au atoms were attractive, thus ultimately facilitating nucleation of two- or three-dimensional metal particles. The presence of the underlying carbide strongly modified the electronic structure and charge density of the supported metal particles resulting in the experimentally proven improved catalytic performance of the resulting systems as compared with cases where the support is an oxide. The electronic perturbations were quite strong for two-dimensional gold particles directly in contact with the carbide substrates and gradually decreased for two-layer and three-layer thick supported particles. While all the metal carbides examined induced a qualitatively similar perturbation on the supported Au particles, the effect is significantly larger for ZrC thus suggesting that the resulting model catalyst would perform even better than the already tried Au/TiC system.

Florez, E.; Feria, L; Vines, F; Rodriguez, J; Illas, F

2009-01-01T23:59:59.000Z

310

Steam reforming on transition-metal carbides from density-functional theory  

E-Print Network [OSTI]

A screening study of the steam reforming reaction (CH_4 + H_2O -> CO + 3H_2) on early transition-metal carbides (TMC's) is performed by means of density-functional theory calculations. The set of considered surfaces includes the alpha-Mo_2C(100) surfaces, the low-index (111) and (100) surfaces of TiC, VC, and delta-MoC, and the oxygenated alpha-Mo_2C(100) and TMC(111) surfaces. It is found that carbides provide a wide spectrum of reactivities towards the steam reforming reaction, from too reactive via suitable to too inert. The reactivity is discussed in terms of the electronic structure of the clean surfaces. Two surfaces, the delta-MoC(100) and the oxygen passivated alpha-Mo_2C(100) surfaces, are identified as promising steam reforming catalysts. These findings suggest that carbides provide a playground for reactivity tuning, comparable to the one for pure metals.

Vojvodic, Aleksandra

2009-01-01T23:59:59.000Z

311

Pressure-induced phase transitions in Pa metal from first-principles theory  

Science Journals Connector (OSTI)

Protactinium metal is shown to undergo a phase transition to the ?-U orthorhombic structure below 1 Mbar pressure. At higher pressures, the bct phase reenters in the phase diagram and at the highest pressures, an ideal hcp structure becomes stable. Hence, Pa undergoes a sequence of transitions; bct??-U?bct?hcp, with the first transition taking place at 0.25 Mbar and the subsequent ones above 1 Mbar. The bct??-U transition is triggered by the pressure-induced promotion of the spd valence states to 5f states. In this regard, Pa approaches uranium which at ambient conditions has one more 5f electron than Pa at similar conditions. At higher compression of Pa, the 5f band broadens and electrostatic interactions in combination with Born-Mayer repulsion become increasingly important and this drives Pa to gradually more close-packed structures. At ultrahigh pressures, the balance between electrostatic energy, Born-Mayer repulsion, and one-electron band energy stabilizes the hcp (ideal packing) structure. The electrostatic energy and Born-Mayer repulsion rule out open crystal structures under these conditions in Pa and between the close-packed structures, the hcp structure is shown to be stabilized by filling of the 5f band.

Per Söderlind and Olle Eriksson

1997-11-01T23:59:59.000Z

312

White lines and d-electron occupancies for the 3d and 4d transition metals  

Science Journals Connector (OSTI)

We used electron-energy-loss spectrometry to measure the intensities of the white lines found at the onsets of the L2 and L3 absorption edges for most of the 3d and 4d transition metals. The intensities of the white lines, normalized to the trailing background, decreased nearly linearly with increasing atomic number, reflecting the filling of the d states. One-electron Hartree-Slater calculations of the white-line intensities were in good agreement with observed spectra. Empirical correlations between normalized white-line intensity and d-state occupancy provide a method for measuring changes in d-state occupancy due to alloying.

D. H. Pearson; C. C. Ahn; B. Fultz

1993-04-01T23:59:59.000Z

313

Exploring a Metal-Insulator Transition with Ultracold Atoms in Standing Light Waves?  

Science Journals Connector (OSTI)

We suggest the possibility to realize an optical quasicrystal with ultracold atoms in far-detuned, bichromatic standing light waves. If the optical potentials created by the individual light waves have sufficiently different strength, one obtains an atom-optical realization of Harper's model. This model exhibits a metal-insulator transition at a certain value of the site-to-site hopping integral. Since this hopping integral is effectively renormalized by an additional oscillating force, one can switch from the regime of extended states to the regime of localized states by varying the amplitude of that force.

Klaus Drese and Martin Holthaus

1997-04-14T23:59:59.000Z

314

Mechanical Instability and Ideal Shear Strength of Transition Metal Carbides and Nitrides  

SciTech Connect (OSTI)

The ideal shear strength of transition metal carbides and nitrides is calculated with the use of the ab initio pseudopotential density functional method. The microscopic mechanism that limits the ideal strength is studied using full atomic and structural relaxation and the results of electronic structure calculations. It is shown that plasticity in perfect crystals can be triggered by electronic instabilities at finite strains. Our study explicitly demonstrates that the ideal strength in these materials is limited by the elastic instability which is in turn initiated by electronic instabilities. The potential application of alloy hardening due to the onset of instabilities at different strains is also discussed.

Jhi, Seung-Hoon; Louie, Steven G.; Cohen, Marvin L.; Morris, J. W.

2001-08-13T23:59:59.000Z

315

Behavior of the thermopower in amorphous materials at the metal-insulator transition C. Villagonzalo , R. A. Romer, and M. Schreiber  

E-Print Network [OSTI]

is the metal-insulator transition (MIT). This quantum phase transition from a good conducting material values or vice versa at low temperature T . This corresponds to a change of thermal conductors fromBehavior of the thermopower in amorphous materials at the metal-insulator transition C

Chemnitz, Technische Universität

316

Secondary cell with orthorhombic alkali metal/manganese oxide phase active cathode material  

DOE Patents [OSTI]

An alkali metal manganese oxide secondary cell is disclosed which can provide a high rate of discharge, good cycling capabilities, good stability of the cathode material, high specific energy (energy per unit of weight) and high energy density (energy per unit volume). The active material in the anode is an alkali metal and the active material in the cathode comprises an orthorhombic alkali metal manganese oxide which undergoes intercalation and deintercalation without a change in phase, resulting in a substantially linear change in voltage with change in the state of charge of the cell. The active material in the cathode is an orthorhombic structure having the formula M.sub.x Z.sub.y Mn.sub.(1-y) O.sub.2, where M is an alkali metal; Z is a metal capable of substituting for manganese in the orthorhombic structure such as iron, cobalt or titanium; x ranges from about 0.2 in the fully charged state to about 0.75 in the fully discharged state, and y ranges from 0 to 60 atomic %. Preferably, the cell is constructed with a solid electrolyte, but a liquid or gelatinous electrolyte may also be used in the cell.

Doeff, Marca M. (Hayward, CA); Peng, Marcus Y. (Cupertino, CA); Ma, Yanping (Albany, CA); Visco, Steven J. (Berkeley, CA); DeJonghe, Lutgard C. (Lafayette, CA)

1996-01-01T23:59:59.000Z

317

Secondary cell with orthorhombic alkali metal/manganese oxide phase active cathode material  

DOE Patents [OSTI]

An alkali metal manganese oxide secondary cell is disclosed which can provide a high rate of discharge, good cycling capabilities, good stability of the cathode material, high specific energy (energy per unit of weight) and high energy density (energy per unit volume). The active material in the anode is an alkali metal and the active material in the cathode comprises an orthorhombic alkali metal manganese oxide which undergoes intercalation and deintercalation without a change in phase, resulting in a substantially linear change in voltage with change in the state of charge of the cell. The active material in the cathode is an orthorhombic structure having the formula M{sub x}Z{sub y}Mn{sub (1{minus}y)}O{sub 2}, where M is an alkali metal; Z is a metal capable of substituting for manganese in the orthorhombic structure such as iron, cobalt or titanium; x ranges from about 0.2 in the fully charged state to about 0.75 in the fully discharged state, and y ranges from 0 to 60 atomic %. Preferably, the cell is constructed with a solid electrolyte, but a liquid or gelatinous electrolyte may also be used in the cell. 11 figs.

Doeff, M.M.; Peng, M.Y.; Ma, Y.; Visco, S.J.; DeJonghe, L.C.

1996-09-24T23:59:59.000Z

318

Final Report: Catalytic Hydrocarbon Reactions over Supported Metal Oxides, August 1, 1995 - July 31, 1999  

SciTech Connect (OSTI)

The research program focused on the catalysis of hydrodesulfurization (HDS) over molybdenum-based catalysts and how catalyst composition, redox ability, structure and neighboring sites control the catalytic properties of metal oxides. We sought to understand the catalytic features/sites that control hydrogenation, hydrogenolysis, and isomerization during HDS. Unprompted silica-supported molybdenum oxides and molybdenum sulfides were studied. Model catalyst systems were prepared from organometallic precursors or cluster compounds to generate supported structures that feature Mo(II) and Mo(IV) cations that are isolated or in ensembles and that have either Mo-O or Mo-S bonds. Conventional MOS{sub 2} catalysts, which contain both edge and rim sites, were be studied. Finally, single-layer MOS{sub 2} structures were also prepared from 2H-MoS{sub 2} powder so that the model systems could be compared against a disulfide catalyst that only involves rim sites. Catalytic reactions for thiophene and tetrahydrothione were studied over the various catalysts. Oxidation states were determined using X-ray photoelectron spectroscopy. X-ray crystallography was used to characterize and follow changes in the MOS{sub 2} structures. The program on metal oxides prepared supported oxides that have a specific structure and oxidation state to serve as model templates for the more complex commercial catalysts and then employed these structures in reaction studies. This focus area examined the relationships between structure and cation redox characteristics in oxidation catalysis. Infrared and Raman spectroscopy were used to characterize the cations and reaction intermediates.

Ekerdt, John G.

1999-07-31T23:59:59.000Z

319

Preparation of iron oxide thin film by metal organic deposition from Fe(III)-acetylacetonate: a study of photocatalytic properties  

Science Journals Connector (OSTI)

Iron oxide thin films have been deposited over fused quartz substrate by simple metal organic deposition from Fe-(III) acetylacetonate as the organic precursor. The decomposition of Fe-acetylacetonate is characterised by its distinct transition temperatures and thermogravimetric loss rates, which have been measured by thermal gravimetric analysis. As-deposited films were sintered in the temperature range 365–800°C and the structural changes of the iron oxide thin films as they transform into different crystalline phases have been studied by X-ray diffraction, Fourier transform infrared spectroscopy, ultraviolet-visible absorption spectroscopy and scanning electron microscopy techniques. Mainly amorphous ?-Fe2O3 is formed at an annealing temperature of approximately 365–400°C, which transforms to ?-Fe2O3 phase with a further increase (600–800°C) in sintering temperature. The film sintered at 800°C consists of mainly crystalline ?-Fe2O3 phase, which shows photocatalytic degradation of an oxygenated aqueous solution of phenol upon visible light illumination.

Bonamali Pal; Maheshwar Sharon

2000-01-01T23:59:59.000Z

320

Study of metallic materials for solid oxide fuel cell interconnect applications.  

SciTech Connect (OSTI)

Metallic interconnect acts as a gas separator and a gas distributor and therefore, it needs to function adequately in two widely different environments. The interconnect material will be exposed to air on one side and natural gas or coal-derived synthesis gas on the other side. The viable material for the interconnect application must be resistant not only to oxidation but also carburization in hydrocarbon containing low-oxygen environments. In addition, the scales that develop on the exposed surfaces must possess adequate electrical conductivity for them to function as current leads over long service life of the fuel cell. This report addresses five topics of interest for the development of metallic interconnects with adequate performance in fuel cells for long service life. The research conducted over the years and the conclusions reached were used to identify additional areas of research on materials for improved performance of components, especially metallic interconnects, in the complex fuel cell environments. This report details research conducted in the following areas: measurement of area specific electrical resistivity, corrosion performance in dual gas environments by experiments using alloy 446, long term corrosion performance of ferritic and austenitic alloys in hydrogen and methane-reformed synthesis fuel-gas environments, approaches to reduce the area resistance of metallic interconnect, and reduction of electrical resistivity of alumina scales on metallic interconnect. Based on the key requirements for metallic interconnects and the data developed on the corrosion behavior of candidate materials in meeting those requirements, several areas are recommended for further research to develop metallic interconnects with acceptable and reliable long-term performance in solid oxide fuel cells.

Natesan, K.; Zeng, Z.; Nuclear Engineering Division

2009-04-24T23:59:59.000Z

Note: This page contains sample records for the topic "transition metal oxide" 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

Composite materials with metal oxide attached to lead chalcogenide nanocrystal quantum dots with linkers  

DOE Patents [OSTI]

Composite materials useful for devices such as photoelectrochemical solar cells include a substrate, a metal oxide film on the substrate, nanocrystalline quantum dots (NQDs) of lead sulfide, lead selenide, and lead telluride, and linkers that attach the NQDs to the metal oxide film. Suitable linkers preserve the 1s absorption peak of the NQDs. A suitable linker has a general structure A-B-C where A is a chemical group adapted for binding to a MO.sub.x and C is a chemical group adapted for binding to a NQD and B is a divalent, rigid, or semi-rigid organic spacer moiety. Other linkers that preserve the 1s absorption peak may also be used.

Fuke, Nobuhiro; Koposov, Alexey Y; Sykora, Milan; Hoch, Laura

2014-12-16T23:59:59.000Z

322

Inert anode containing oxides of nickel iron and cobalt useful for the electrolytic production of metals  

DOE Patents [OSTI]

An inert anode for the electrolytic production of metals such as aluminum is disclosed. The inert anode includes a ceramic oxide material preferably made from NiO, Fe.sub.2 O.sub.3 and CoO. The inert anode composition may comprise the following mole fractions of NiO, Fe.sub.2 O.sub.3 and CoO: 0.15 to 0.99 NiO; 0.0001 to 0.85 Fe.sub.2 O.sub.3 ; and 0.0001 to 0.45 CoO. The inert anode may optionally include other oxides and/or at least one metal phase, such as Cu, Ag, Pd, Pt, Au, Rh, Ru, Ir and/or Os. The Ni--Fe--Co--O ceramic material exhibits very low solubility in Hall cell baths used to produce aluminum.

Ray, Siba P. (Murrysville, PA); Liu, Xinghua (Monroeville, PA); Weirauch, Jr., Douglas A. (Murrysville, PA)

2002-01-01T23:59:59.000Z

323

Inert anode containing oxides of nickel, iron and zinc useful for the electrolytic production of metals  

DOE Patents [OSTI]

An inert anode for the electrolytic production of metals such as aluminum is disclosed. The inert anode includes a ceramic oxide material preferably made from NiO, Fe.sub.2 O.sub.3 and ZnO. The inert anode composition may comprise the following mole fractions of NiO, Fe.sub.2 O.sub.3 and ZnO: 0.2 to 0.99 NiO; 0.0001 to 0.8 Fe.sub.2 O.sub.3 ; and 0.0001 to 0.3 ZnO. The inert anode may optionally include other oxides and/or at least one metal phase, such as Cu, Ag, Pd, Pt, Au, Rh, Ru, Ir and/or Os. The Ni--Fe--Co--O ceramic material exhibits very low solubility in Hall cell baths used to produce aluminum.

Ray, Siba P. (Murrysville, PA); Weirauch, Jr., Douglas A. (Murrysville, PA); Liu, Xinghua (Monroeville, PA)

2002-01-01T23:59:59.000Z

324

Thermodynamics of the ferromagnetic phase transition in nearly half metallic CoS2 at high pressures  

SciTech Connect (OSTI)

The volume change and heat capacity at the ferromagnetic phase transition in COS2 were measured at high pressures using X-rays generated by the Argonne synchrotron light source and by ac-calorimetry, respectively. The transition entropy, calculated on the basis of these experimental data, drops along the transition line due to quantum degradation, as required by Nernst's law. The volume change increases strongly along the transition line, which is explained by specifics of the compressibility difference of coexisting phases that results from nearly half metallic nature of the ferromagnetic phase of COS2. (C) 2013 Elsevier Ltd. All rights reserved.

Elkin, F. S. [Institute for High Pressure Physics of Russian Academy of Sciences; Zibrov, I. P. [Institute for High Pressure Physics of Russian Academy of Sciences; Novikov, A. P. [Institute for High Pressure Physics of Russian Academy of Sciences; Khasanov, S. S. [Institute for Solid State Physics Russian Academy of Sciences; Sidorov, V. A. [Institute for High Pressure Physics of Russian Academy of Sciences; Petrova, A. E. [Institute for High Pressure Physics of Russian Academy of Sciences; Lograsso, Thomas A. [Ames Laboratory; Thompson, J. D. [Los Alamos National Laboratory; Stishov, S. M. [Institute for High Pressure Physics of Russian Academy of Sciences

2013-12-06T23:59:59.000Z

325

A New Mechanism of Charge Density Wave Discovered in Transition Metal  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

8 8 A New Mechanism of Charge Density Wave Discovered in Transition Metal Dichalcogenides Charge density waves (CDW) are a type of coupled electronic-lattice instability found in quasi-low dimensional materials. The driving force behind the instability is the reduction in energy of electrons in the material as a consequence of establishing a spontaneous periodic modulation of the crystalline lattice with an appropriate wave vector. The symmetry of the CDW state is very sensitive to the electronic structure of the host material. Charge density wave has been observed in quasi-one dimensional compounds, high temperature superconductors, manganites and many others.1-4 Conventionally, Fermi surface nesting is the dominant and textbook mechanism for CDW. However, it fails to explain the CDW in the 2H-structured transition metal dichalcogenides (2H-TMD's), which is actually the first two-dimensional CDW materials discovered in 1975.5 Even after three decades of intensive research on this subject, the CDW mechanism of 2H-TMD's remain mysterious and controversial.

326

Kinetics and mechanism of thiophene hydrodesulfurization over carbon-supported transition metal sulfides  

SciTech Connect (OSTI)

Results of a detailed kinetic study on the thiophene hydrodesulfurization reaction at atmospheric pressure over a set of carbon-supported transition metal sulfides, i.e., the sulfides of Co, Mo, Rh, and the mixed CoMo sulfide, are presented. It is found that (partially) hydrogenated thiophenes, i.e., 2,3-dihydrothiophene, 2,5-dihydrothiophene, and tetrahydrothiophene, are important intermediates in the reaction mechanism. The reaction orders of thiophene suggest that carbon-sulfur bond cleavage is rate limiting for most of the catalysts. The CoMo catalyst may have hydrogenative sulfur removal as the rate limiting step. This catalyst shows a strong decrease in apparent activation energy with temperature to be ascribed to a large change in steady state surface coverage by thiophene (or H{sub 2}S) as a function of temperature. This is consistent with a strong interaction between catalyst and thiophene. The Rh catalyst most probably shows a phase transition leading to different kinetic parameters. A strong interaction between the metal sulfide and thiophene is important for a high HDS activity. 38 refs., 4 figs., 5 tabs.

Hensen, E.J.M.; Vissenberg, M.J.; Beer, V.H.J. de [Eindhoven Univ. of Technology (Netherlands)] [and others] [Eindhoven Univ. of Technology (Netherlands); and others

1996-10-01T23:59:59.000Z

327

Pseudocrystalline model of the magnetic anisotropy in amorphous rare-earth–transition-metal thin films  

Science Journals Connector (OSTI)

A pseudocrystalline model is proposed to explain the occurrence of perpendicular anisotropy in amorphous rare-earth–transition metal (R-T) thin films. It is based on the central hypothesis that during layer-by-layer growth small planar hexagonal units are formed defining on average a preferential axis perpendicular to the film plane. The units are similar in structure to relaxed crystalline ones and are estimated to typically comprise six rare-earth atoms. They are regarded as an idealized model of the short-range order and are consistent with the known nearest-neighbor R-T and T-T coordination numbers in the amorphous state. This model is able to explain the known experimental results concerning the influence of composition, substrate temperature, annealing, and bombardment effects during sputter deposition on the magnetic anisotropy of thin amorphous rare-earth–transition-metal films of the system (Nd, Tb, Dy) (Fe, Co), as well as the destruction of this anisotropy by additives.

D. Mergel; H. Heitmann; P. Hansen

1993-01-01T23:59:59.000Z

328

Performance limits of tunnel transistors based on mono-layer transition-metal dichalcogenides  

SciTech Connect (OSTI)

Performance limits of tunnel field-effect transistors based on mono-layer transition metal dichalcogenides are investigated through numerical quantum mechanical simulations. The atomic mono-layer nature of the devices results in a much smaller natural length ?, leading to much larger electric field inside the tunneling diodes. As a result, the inter-band tunneling currents are found to be very high as long as ultra-thin high-k gate dielectric is possible. The highest on-state driving current is found to be close to 600??A/?m at V{sub g}?=?V{sub d}?=?0.5?V when 2?nm thin HfO{sub 2} layer is used for gate dielectric, outperforming most of the conventional semiconductor tunnel transistors. In the five simulated transition-metal dichalcogenides, mono-layer WSe{sub 2} based tunnel field-effect transistor shows the best potential. Deep analysis reveals that there is plenty room to further enhance the device performance by either geometry, alloy, or strain engineering on these mono-layer materials.

Jiang, Xiang-Wei, E-mail: xwjiang@semi.ac.cn; Li, Shu-Shen [State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China); Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China)

2014-05-12T23:59:59.000Z

329

DFT calculations of EPR parameters of transition metal complexes: Implications for catalysis  

SciTech Connect (OSTI)

Transition metal and ligand hyperfine coupling constants for paramagnetic vanadium and copper model complexes have been calculated using DFT methods that are available in commercial software packages. Variations in EPR parameters with ligand identity and ligand orientation are two of the trends that have been investigated with DFT calculations. For example, the systematic variation of the vanadium hyperfine coupling constant with orientation for an imidazole ligand in a VO2+ complex has been observed experimentally and has also been reproduced by DFT calculations. Similarly, changes in the vanadium hyperfine coupling constant with ligand binding have been calculated using model complexes and DFT methods. DFT methods were also used to calculate ligand hyperfine coupling constants in transition metal systems. The variation of the proton hyperfine coupling constant with water ligand orientation was investigated for [VO(H2O)5]2+ and the results were used to interpret high resolution EPR data of VO2+-exchanged zeolites. Nitrogen hyperfine and quadrupole coupling constants for VO2+ model complexes were calculated and compared with experimental data. The computational results were used to enhance the interpretation of the EPR data for vanadium-exchanged zeolites which are promising catalytic materials. The implications of the DFT calculations of EPR parameters with respect to catalysis will be discussed

Saladino, Alexander C.; Larsen, Sarah C.

2005-07-15T23:59:59.000Z

330

Compressibilities and phonon spectra of high-hardness transition metal-nitride materials  

SciTech Connect (OSTI)

We report compressibilities measured by synchrotron X-ray diffraction and phonon spectra from Raman scattering at high pressure in the diamond anvil cell (DAC) for cubic transition metal nitrides TiN{sub 1-x}, {gamma}-Mo{sub 2}N and VN{sub x}. The high-hardness metal nitride compounds have large values of the bulk modulus. B1-structured nitrides normally have no allowed first-order Raman spectra. However, they exhibit broad bands that reflect the vibrational density of states g({omega}) associated with breakdown of q=0 selection rules because of the presence of N{sup 3-} vacancies on anion sites. Peaks in g({omega}) at low frequency are identified with the longitudinal and transverse acoustic (TA) branches. The maximum in the TA band is correlated with the superconducting transition temperature in these materials (T{sub c}). In situ Raman scattering measurements in the DAC thus permit predictions of the T{sub c} variation with pressure for cubic nitrides and isostructural carbide materials.

Shebanova, O.; Soignard, E.; Mcmillan, P.F. (ASU); (UCL)

2010-01-20T23:59:59.000Z

331

Electronic Structure of Transition Metal Clusters, Actinide Complexes and Their Reactivities  

SciTech Connect (OSTI)

This is a continuing DOE-BES funded project on transition metal and actinide containing species, aimed at the electronic structure and spectroscopy of transition metal and actinide containing species. While a long term connection of these species is to catalysis and environmental management of high-level nuclear wastes, the immediate relevance is directly to other DOE-BES funded experimental projects at DOE-National labs and universities. There are a number of ongoing gas-phase spectroscopic studies of these species at various places, and our computational work has been inspired by these experimental studies and we have also inspired other experimental and theoretical studies. Thus our studies have varied from spectroscopy of diatomic transition metal carbides to large complexes containing transition metals, and actinide complexes that are critical to the environment. In addition, we are continuing to make code enhancements and modernization of ALCHEMY II set of codes and its interface with relativistic configuration interaction (RCI). At present these codes can carry out multi-reference computations that included up to 60 million configurations and multiple states from each such CI expansion. ALCHEMY II codes have been modernized and converted to a variety of platforms such as Windows XP, and Linux. We have revamped the symbolic CI code to automate the MRSDCI technique so that the references are automatically chosen with a given cutoff from the CASSCF and thus we are doing accurate MRSDCI computations with 10,000 or larger reference space of configurations. The RCI code can also handle a large number of reference configurations, which include up to 10,000 reference configurations. Another major progress is in routinely including larger basis sets up to 5g functions in thee computations. Of course higher angular momenta functions can also be handled using Gaussian and other codes with other methods such as DFT, MP2, CCSD(T), etc. We have also calibrated our RECP methods with all-electron Douglas-Kroll relativistic methods. We have the capabilities for computing full CI extrapolations including spin-orbit effects and several one-electron properties and electron density maps including spin-orbit effects. We are continuously collaborating with several experimental groups around the country and at National Labs to carry out computational studies on the DOE-BES funded projects. The past work in the last 3 years was primarily motivated and driven by the concurrent or recent experimental studies on these systems. We were thus significantly benefited by coordinating our computational efforts with experimental studies. The interaction between theory and experiment has resulted in some unique and exciting opportunities. For example, for the very first time ever, the upper spin-orbit component of a heavy trimer such as Au{sub 3} was experimentally observed as a result of our accurate computational study on the upper electronic states of gold trimer. Likewise for the first time AuH{sub 2} could be observed and interpreted clearly due to our computed potential energy surfaces that revealed the existence of a large barrier to convert the isolated AuH{sub 2} back to Au and H{sub 2}. We have also worked on yet to be observed systems and have made predictions for future experiments. We have computed the spectroscopic and thermodynamic properties of transition metal carbides transition metal clusters and compared our electronic states to the anion photodetachment spectra of Lai Sheng Wang. Prof Mike Morse and coworkers(funded also by DOE-BES) and Prof Stimle and coworkers(also funded by DOE-BES) are working on the spectroscopic properties of transition metal carbides and nitrides. Our predictions on the excited states of transition metal clusters such as Hf{sub 3}, Nb{sub 2}{sup +} etc., have been confirmed experimentally by Prof. Lombardi and coworkers using resonance Raman spectroscopy. We have also been studying larger complexes critical to the environmental management of high-level nuclear wastes. In collaboration with experimental co

Krishnan Balasubramanian

2009-07-18T23:59:59.000Z

332

The steady-state thermal-hydraulic performance of 3500 MWth metal and oxide fueled LMRs  

SciTech Connect (OSTI)

The thermal-hydraulic performance of a 3500 MWth metal and oxide fueled LMR is reported. Orifice zones are defined and coolant flowrates are given for use in safety analyses. The flux calculations were carried out in three-dimensional hexagonal-Z geometry using a finite differenced diffusion theory code. The heating calculations included the transport and deposition of gamma energy. The assembly temperature calculations were performed using a subchannel code.

Vilim, R.B.; Hill, R.N.

1989-03-01T23:59:59.000Z

333

Surface Science Letters Bulk-defect dependent adsorption on a metal oxide surface  

E-Print Network [OSTI]

-6028(01)01067-6 #12;Titanium dioxide is a wide-band gap semicon- ductor (Egap 3 eV) that can easily be reducedSurface Science Letters Bulk-defect dependent adsorption on a metal oxide surface: S/TiO2(1 1 0) E Abstract The adsorption of molecular sulfur on TiO2(1 1 0)(1 Ã? 1) has been studied with scanning tunneling

Diebold, Ulrike

334

Beyond the Lone-Pair Model for Structurally Distorted Metal Oxides  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Beyond the Lone-Pair Model for Structurally Distorted Metal Oxides Print Beyond the Lone-Pair Model for Structurally Distorted Metal Oxides Print "Ferroelectricity," by analogy to ferromagnetism, is defined as the presence of spontaneous electrical polarization in a material, often arising from distortions in the material's crystal structure. In oxides of the metals lead and bismuth, such distortions were for many years attributed to the existence of "lone pair" electrons: pairs of chemically inert, nonbonding valence electrons in hybrid orbitals that leave noticeable voids in the crystal structure. At the ALS, researchers from the U.K., Ireland, and the U.S. have now obtained definitive experimental evidence that this lone-pair model must be revised. High-resolution x-ray photoemission spectroscopy (XPS) and soft x-ray emission spectroscopy (XES) have clarified the subtle electronic origins of the prototypical distortions in these crystal structures. The results have important implications for the tantalizing possibility of spintronic or superconducting devices combining ferroelectric and ferromagnetic properties.

335

Beyond the Lone-Pair Model for Structurally Distorted Metal Oxides  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Beyond the Lone-Pair Model for Structurally Distorted Metal Oxides Print Beyond the Lone-Pair Model for Structurally Distorted Metal Oxides Print "Ferroelectricity," by analogy to ferromagnetism, is defined as the presence of spontaneous electrical polarization in a material, often arising from distortions in the material's crystal structure. In oxides of the metals lead and bismuth, such distortions were for many years attributed to the existence of "lone pair" electrons: pairs of chemically inert, nonbonding valence electrons in hybrid orbitals that leave noticeable voids in the crystal structure. At the ALS, researchers from the U.K., Ireland, and the U.S. have now obtained definitive experimental evidence that this lone-pair model must be revised. High-resolution x-ray photoemission spectroscopy (XPS) and soft x-ray emission spectroscopy (XES) have clarified the subtle electronic origins of the prototypical distortions in these crystal structures. The results have important implications for the tantalizing possibility of spintronic or superconducting devices combining ferroelectric and ferromagnetic properties.

336

Oxidation Resistant, Cr Retaining, Electrically Conductive Coatings on Metallic Alloys for SOFC Interconnects  

SciTech Connect (OSTI)

This report describes significant results from an on-going, collaborative effort to enable the use of inexpensive metallic alloys as interconnects in planar solid oxide fuel cells (SOFCs) through the use of advanced coating technologies. Arcomac Surface Engineering, LLC, under the leadership of Dr. Vladimir Gorokhovsky, is investigating filtered-arc and filtered-arc plasma-assisted hybrid coating deposition technologies to promote oxidation resistance, eliminate Cr volatility, and stabilize the electrical conductivity of both standard and specialty steel alloys of interest for SOFC metallic interconnect (IC) applications. Arcomac has successfully developed technologies and processes to deposit coatings with excellent adhesion, which have demonstrated a substantial increase in high temperature oxidation resistance, stabilization of low Area Specific Resistance values and significantly decrease Cr volatility. An extensive matrix of deposition processes, coating compositions and architectures was evaluated. Technical performance of coated and uncoated sample coupons during exposures to SOFC interconnect-relevant conditions is discussed, and promising future directions are considered. Cost analyses have been prepared based on assessment of plasma processing parameters, which demonstrate the feasibility of the proposed surface engineering process for SOFC metallic IC applications.

Vladimir Gorokhovsky

2008-03-31T23:59:59.000Z

337

Plasmonic transparent conducting metal oxide nanoparticles and nanoparticle films for optical sensing applications  

SciTech Connect (OSTI)

The ability to monitor gas species selectively, sensitively, and reliably in extreme temperatures and harsh conditions is critically important for more efficient energy production using conventional fossil energy based production technologies, enabling advanced technologies for fossil based power plants of the future, and improving efficiency in domestic manufacturing industries. Optical waveguide based sensing platforms have become increasingly important but a need exists for materials that exhibit useful changes in optical properties in response to changing gas atmospheres at high temperatures. In this manuscript, the onset of a near-IR absorption associated with an increase in free carrier density in doped metal oxide nanoparticles to form so-called conducting metal oxides is discussed in the context of results obtained for undoped and Al-doped ZnO nanoparticle based films. Detailed film characterization results are presented along with measured changes in optical absorption resulting from various high temperature treatments in a range of gas atmospheres. Optical property changes are also discussed in the context of a simple model for optical absorption in conducting metal oxide nanoparticles and thin films. The combination of experimental results and theoretical modeling presented here suggests that such materials have potential for high temperature optical gas sensing applications. Simulated sensing experiments were performed at 500 °C and a useful, rapid, and reproducible near-IR optical sensing response to H{sub 2} confirms that this class of materials shows great promise for optical gas sensing.

Ohodnicki, Paul R., Jr.; Wang, Congjun; Andio, Mark

2013-07-31T23:59:59.000Z

338

Activation of Noble Metals on Metal-Carbide Surfaces: Novel Catalysts for CO Oxidation, Desulfurization and Hydrogenation Reactions  

SciTech Connect (OSTI)

This perspective article focuses on the physical and chemical properties of highly active catalysts for CO oxidation, desulfurization and hydrogenation reactions generated by depositing noble metals on metal-carbide surfaces. To rationalize structure-reactivity relationships for these novel catalysts, well-defined systems are required. High-resolution photoemission, scanning tunneling microscopy (STM) and first-principles periodic density-functional (DF) calculations have been used to study the interaction of metals of Groups 9, 10 and 11 with MC(001) (M = Ti, Zr, V, Mo) surfaces. DF calculations give adsorption energies that range from 2 eV (Cu, Ag, Au) to 6 eV (Co, Rh, Ir). STM images show that Au, Cu, Ni and Pt grow on the carbide substrates forming two-dimensional islands at very low coverage, and three-dimensional islands at medium and large coverages. In many systems, the results of DF calculations point to the preferential formation of admetal-C bonds with significant electronic perturbations in the admetal. TiC(001) and ZrC(001) transfer some electron density to the admetals facilitating bonding of the adatom with electron-acceptor molecules (CO, O{sub 2}, C{sub 2}H{sub 4}, SO{sub 2}, thiophene, etc.). For example, the Cu/TiC(001) and Au/TiC(001) systems are able to cleave both S-O bonds of SO{sub 2} at a temperature as low as 150 K, displaying a reactivity much larger than that of TiC(001) or extended surfaces of bulk copper and gold. At temperatures below 200 K, Au/TiC is able to dissociate O{sub 2} and perform the 2CO + O{sub 2} {yields} 2CO{sub 2} reaction. Furthermore, in spite of the very poor hydrodesulfurization performance of TiC(001) or Au(111), a Au/TiC(001) surface displays an activity for the hydrodesulfurization of thiophene higher than that of conventional Ni/MoS{sub x} catalysts. In general, the Au/TiC system is more chemically active than systems generated by depositing Au nanoparticles on oxide surfaces. Thus, metal carbides are excellent supports for enhancing the chemical reactivity of noble metals.

Rodriguez J. A.; Illas, F.

2012-01-01T23:59:59.000Z

339

Electronic and mechanical properties of 5d transition metal mononitrides via first principles  

SciTech Connect (OSTI)

The electronic and mechanical properties of 5d transition metal mononitrides from LaN to AuN are systematically investigated by use of the density-functional theory. For each nitride, six structures are considered, i.e., rocksalt, zinc blende, CsCl, wurtzite, NiAs and WC structures. Among the considered structures, rocksalt structure is the most stable for LaN, HfN and AuN, WC structure for TaN, NiAs structure for WN, wurtzite structure for ReN, OsN, IrN and PtN. The most stable structure for each nitride is mechanically stable. The formation enthalpy increases from LaN to AuN. For LaN, HfN and TaN, the formation enthalpy is negative for all the considered structures, while from WN to AuN, except wurtzite structure in ReN, the formation enthalpy is positive. The calculated density of states shows that they are all metallic. ReN in NiAs structure has the largest bulk modulus, 418 GPa. The largest shear modulus 261 GPa is from TaN in WC structure. Trends are discussed. - Graphical abstract: Formation enthalpy per formula unit {delta}H (eV) for all the considered structures of 5d transition metal mononitrides MN (M=La-Au). It was shown that the formation enthalpy increases from LaN to AuN. The nitrides with negative values indicate that they can be synthesized experimentally at ambient conditions.

Zhao Erjun [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Graduate School, Chinese Academy of Sciences, Beijing 100049 (China); Wu Zhijian [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China)], E-mail: zjwu@ciac.jl.cn

2008-10-15T23:59:59.000Z

340

Catalytic activity of tetravalent metal phosphates and phosphonates on the oxidation of (+)-3-carene  

Science Journals Connector (OSTI)

Tetravalent metal phosphates and phosphonates form highly insoluble inorganic polymers and can act as good catalysts in some oxidative reactions. In the present work, zirconium phosphate amorphous (ZrPA), scandium exchanged zirconium phosphate amorphous (ScZrPA), sodium exchanged zirconium phosphate amorphous (NaZrPA), potassium exchanged zirconium phosphate amorphous (KZrPA), zirconium phenylphosphonate amorphous (ZrPPA) and zirconium phenylphosphonate phosphate amorphous (ZrPA/ZrPPA), were prepared and evaluated as catalysts for the oxidation of 3,7,7-trimethylbicyclo[4.1.0]hept-3-ene [(+)-3-carene)] by hydrogen peroxide, in different solvents. It was found that the oxidation reaction of (+)-3-carene yielded three major products, namely ?-3,4-epoxycarane, carane-3?,4?-diol and 3?-acetoxycaran-4?-ol, depending on the catalyst and solvent conditions. No ?-3,4-epoxycarane was detected in the studied conditions.

Graça M.S.R.O. Rocha; Rui M.A. Domingues; Mário M.Q. Simões; Artur M.S. Silva

2009-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "transition metal oxide" 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

Modelling of thermo-mechanical and irradiation behavior of metallic and oxide fuels for sodium fast reactors  

E-Print Network [OSTI]

A robust and reliable code to model the irradiation behavior of metal and oxide fuels in sodium cooled fast reactors is developed. Modeling capability was enhanced by adopting a non-empirical mechanistic approach to the ...

Karahan, Aydin

2009-01-01T23:59:59.000Z

342

Recent trends in the microwave-assisted synthesis of metal oxide nanoparticles supported on carbon nanotubes and their applications  

Science Journals Connector (OSTI)

The study of coating carbon nanotubes with metal/oxides nanoparticles is now becoming a promising and challenging area of research. To optimize the use of carbon nanotubes in various applications, it is necessary to attach functional groups or other ...

Sarah C. Motshekga; Sreejarani K. Pillai; Suprakas Sinha Ray; Kalala Jalama; Rui. W. M. Krause

2012-01-01T23:59:59.000Z

343

First-Principles Study of MetalCarbide/Nitride Adhesion: Al/VC vs. Al/VN Donald J. Siegel  

E-Print Network [OSTI]

-oxide ce- ramics. Within this class, the transition metal carbides and ni- trides are a particularly knowledge, there have been only three studies of adhesion between metals and transition metal carbidesFirst-Principles Study of Metal­Carbide/Nitride Adhesion: Al/VC vs. Al/VN Donald J. Siegel

Adams, James B

344

Electrocatalytic Measurement Methodology of Oxide Catalysts Using a Thin-Film Rotating Disk Electrode  

E-Print Network [OSTI]

Transition-metal oxides can exhibit high electrocatalytic activity for reactions such as the oxygen reduction reaction (ORR) in alkaline media. It is often difficult to measure and compare the activities of oxide catalysts ...

Suntivich, Jin

345

Modifications of the surface properties of metals by oxide overlayers: 1, Oxidized zirconium deposited on the Pt(100) single crystal surface  

SciTech Connect (OSTI)

Metallic zirconium was deposited on a single crystal Pt(100) surface by thermal evaporation in UHV conditions. The deposit was oxidized by exposure to oxygen immediately after deposition. Oxidized zirconium was found to grow on the platinum ace by the layer-by-layer mechanism. The adsorption of carbon monoxide on the surface was studied as a function of the zirconium coverage. The results show that oxidized zirconium forms a chemically inert layer which blocks the adsorptive sites of the underlying platinum substrate. The properties of the free Pt surface were unaffected by the presence of the oxidized zirconium layer.

Bardi, U.; Ross, P.N.

1986-06-01T23:59:59.000Z

346

Photochemical activation and reactivity of polynuclear transition metal complex molecules. Progress report, June, 1980-May 31, 1981  

SciTech Connect (OSTI)

Progress on this project during the past year has proceeded in three different but complementary directions. The first involves a continuing effort to synthesize new and unusual polynuclear transition metal complexes that (1) exhibit multi-electron transfer reactions, (2) can be expected to have long-lived excited states, and/or (3) will undergo photochemically initiated intramolecular energy transfer to produce reactive species. The second involves the electrochemical investigation of multi-electron transfer reactions of polynuclear transition metal complexes. The third is concerned with the study of the photophysics of binuclear complexes in which electron transfer could take place between a photochemically excited metal ion and the metal ion in the same molecule thereby producing two new reactive sites.

Endicott, J.F.; Lintvedt, R.L.

1981-01-01T23:59:59.000Z

347

Hydrogen Peroxide Formation in a Surrogate Lung Fluid by Transition Metals and Quinones Present in Particulate Matter  

Science Journals Connector (OSTI)

To address this, we use a cell-free, surrogate lung fluid (SLF) to quantify the initial rate of HOOH formation from 10 transition metals and 4 quinones commonly identified in PM. ... Copper, 1,2-naphthoquinone, 1,4-naphthoquinone, and phenanthrenequinone all form HOOH in a SLF, but only copper and 1,2-naphthoquinone are likely important at ambient concentrations. ... Given the uncertainties in our understanding of HOOH production from ambient PM, our purpose is to quantify HOOH formation from transition metals and quinones (both individually and in mixtures) in a more representative (though still cell-free) surrogate lung fluid (SLF). ...

Jessica G. Charrier; Alexander S. McFall; Nicole K. Richards-Henderson; Cort Anastasio

2014-05-23T23:59:59.000Z

348

From electronic structure to catalytic activity: A single descriptor for adsorption and reactivity on transition-metal carbides  

E-Print Network [OSTI]

Adsorption and catalytic properties of the polar (111) surface of transition-metal carbides (TMC's) are investigated by density-functional theory. Atomic and molecular adsorption are rationalized with the concerted-coupling model, in which two types of TMC surface resonances (SR's) play key roles. The transition-metal derived SR is found to be a single measurable descriptor for the adsorption processes, implying that the Br{\\o}nsted-Evans-Polanyi relation and scaling relations apply. This gives a picture with implications for ligand and vacancy effects and which has a potential for a broad screening procedure for heterogeneous catalysts.

Vojvodic, Aleksandra; Ruberto, Carlo; Lundqvist, Bengt I

2009-01-01T23:59:59.000Z

349

Solid oxide fuel cell with transitioned cross-section for improved anode gas management at the open end  

DOE Patents [OSTI]

A solid oxide fuel cell (400) is made having a tubular, elongated, hollow, active section (445) which has a cross-section containing an air electrode (452) a fuel electrode (454) and solid oxide electrolyte (456) between them, where the fuel cell transitions into at least one inactive section (460) with a flattened parallel sided cross-section (462, 468) each cross-section having channels (472, 474, 476) in them which smoothly communicate with each other at an interface section (458).

Zafred, Paolo R. (Murrysville, PA); Draper, Robert (Pittsburgh, PA)

2012-01-17T23:59:59.000Z

350

IEEE TRANSACTIONS ON NANOTECHNOLOGY, VOL. 10, NO. 3, MAY 2011 499 TiSi2 Nanocrystal Metal Oxide Semiconductor Field  

E-Print Network [OSTI]

IEEE TRANSACTIONS ON NANOTECHNOLOGY, VOL. 10, NO. 3, MAY 2011 499 TiSi2 Nanocrystal Metal Oxide memory window, faster writing and erasing, and longer retention lifetime as a result of the metallic property of the silicide NCs. Due to thermally stable, CMOS compatible properties, TiSi2 NCs are highly

Yang, Zheng

351

Photovoltaic effect in transition metal modified polycrystalline BiFeO3 thin films  

Science Journals Connector (OSTI)

We report photovoltaic (PV) effect in multiferroic Bi0.9Sm0.1Fe0.95Co0.05O3 (BSFCO) thin films. Transition metal modified polycrystalline BiFeO3 (BFO) thin films have been deposited on Pt/TiO2/SiO2/Si substrate successfully through pulsed laser deposition (PLD). PV response is observed under illumination both in sandwich and lateral electrode configurations. The open-circuit voltage (Voc) and the short-circuit current density (Jsc) of the films in sandwich electrode configuration under illumination are measured to be 0.9 V and ?0.051 µA cm?2. Additionally, we report piezoresponse for BSFCO films, which confirms ferroelectric piezoelectric behaviour.

Venkata Sreenivas Puli; Dhiren Kumar Pradhan; Rajesh Kumar Katiyar; Indrani Coondoo; Neeraj Panwar; Pankaj Misra; Douglas B Chrisey; J F Scott; Ram S Katiyar

2014-01-01T23:59:59.000Z

352

Dirac cones in artificial structures of 3d transitional-metals doped Mg-Al spinels  

SciTech Connect (OSTI)

Motivated by recent theoretical predications for Dirac cone in two-dimensional (2D) triangular lattice [H. Ishizuka, Phys. Rev. Lett. 109, 237207 (2012)], first-principles studies are performed to predict Dirac cones in artificial structures of 3d transitional-metals (TM?=?Ti, V, Cr, Mn, Fe, Co, Ni, and Cu) doped Mg-Al spinels. In investigated artificial structures, TM dopants substitute specific positions of the B sub-lattice in Mg-Al spinel, and form a quasi-2D triangular lattice in the a-b plane. Calculated results illustrate the existence of the spin-polarized Dirac cones formed in d-wave bands at (around) the K-point in the momentum space. The study provides a promising route for engineering Dirac physics in condensed matters.

Lu, Yuan; Zuo, Xu, E-mail: xzuo@nankai.edu.cn [College of Electronic Information and Optical Engineering, Nankai University, Tianjin 300071 (China); Feng, Min [School of Physics, Nankai University, Tianjin 300071 (China); Shao, Bin [Department of Physics, Tsinghua University, Beijing 100084 (China)

2014-05-07T23:59:59.000Z

353

Spin Hall effect in spin-valley coupled monolayers of transition metal dichalcogenides  

SciTech Connect (OSTI)

We study both the intrinsic and extrinsic spin Hall effect in spin-valley coupled monolayers of transition metal dichalcogenides. We find that whereas the skew-scattering contribution is suppressed by the large band gap, the side-jump contribution is comparable to the intrinsic one with opposite sign in the presence of scalar andmagnetic scattering. Intervalley scattering tends to suppress the side-jump contribution due to the loss of coherence. By tuning the ratio of intra- to intervalley scattering, the spin Hall conductivity shows a sign change in hole-doped samples. The multiband effect in other doping regimes is considered, and it is found that the sign change exists in the heavily hole-doped regime, but not in the electron-doped regime.

Shan, Wen-Yu [Carnegie Mellon University (CMU); Lu, Hai-Zhou [University of Hong Kong, The; Xiao, Di [Carnegie Mellon University (CMU)

2013-01-01T23:59:59.000Z

354

Transition Metal Catalyzed Reactions of Carbohydrates: a Nonoxidative Approach to Oxygenated Organics  

SciTech Connect (OSTI)

There is a critical need for new environmentally friendly processes in the United States chemical industry as legislative and economic pressures push the industry to zero-waste and cradle-to-grave responsibility for the products they produce. Carbohydrates represent a plentiful, renewable resource, which for some processes might economically replace fossil feedstocks. While the conversion of biomass to fuels, is still not generally economical, the selective synthesis of a commodity or fine chemical, however, could compete effectively if appropriate catalytic conversion systems can be found. Oxygenated organics, found in a variety of products such as nylon and polyester, are particularly attractive targets. We believe that with concerted research efforts, homogeneous transition metal catalyzed reactions could play a significant role in bringing about this future green chemistry technology.

Andrews, Mark

1997-01-08T23:59:59.000Z

355

Thermoelectric material including a multiple transition metal-doped type I clathrate crystal structure  

DOE Patents [OSTI]

A thermoelectric material includes a multiple transition metal-doped type I clathrate crystal structure having the formula A.sub.8TM.sub.y.sub.1.sup.1TM.sub.y.sub.2.sup.2 . . . TM.sub.y.sub.n.sup.nM.sub.zX.sub.46-y.sub.1.sub.-y.sub.2.sub.- . . . -y.sub.n.sub.-z. In the formula, A is selected from the group consisting of barium, strontium, and europium; X is selected from the group consisting of silicon, germanium, and tin; M is selected from the group consisting of aluminum, gallium, and indium; TM.sup.1, TM.sup.2, and TM.sup.n are independently selected from the group consisting of 3d, 4d, and 5d transition metals; and y.sub.1, y.sub.2, y.sub.n and Z are actual compositions of TM.sup.1, TM.sup.2, TM.sup.n, and M, respectively. The actual compositions are based upon nominal compositions derived from the following equation: z=8q.sub.A-|.DELTA.q.sub.1|y.sub.1-|.DELTA.q.sub.2|y.sub.2- . . . -|.DELTA.q.sub.n|y.sub.n, wherein q.sub.A is a charge state of A, and wherein .DELTA.q.sub.1, .DELTA.q.sub.2, .DELTA.q.sub.n are, respectively, the nominal charge state of the first, second, and n-th TM.

Yang, Jihui (Lakeshore, CA); Shi, Xun (Troy, MI); Bai, Shengqiang (Shanghai, CN); Zhang, Wenqing (Shanghai, CN); Chen, Lidong (Shanghai, CN); Yang, Jiong (Shanghai, CN)

2012-01-17T23:59:59.000Z

356

REFORMULATION OF COAL-DERIVED TRANSPORTATION FUELS: SELECTIVE OXIDATION OF CARBON MONOXIDE ON METAL FOAM CATALYSTS  

SciTech Connect (OSTI)

Uses for structured catalytic supports, such as ceramic straight-channel monoliths and ceramic foams, have been established for a long time. One of the most prominent examples is the washcoated ceramic monolith as a three-way catalytic converter for gasoline-powered automobiles. A distinct alternative to the ceramic monolith is the metal foam, with potential use in fuel cell-powered automobiles. The metal foams are characterized by their pores per inch (ppi) and density ({rho}). In previous research, using 5 wt% platinum (Pt) and 0.5 wt% iron (Fe) catalysts, washcoated metal foams, 5.08 cm in length and 2.54 cm in diameter, of both varying and similar ppi and {rho} were tested for their activity (X{sub CO}) and selectivity (S{sub CO}) on a CO preferential oxidation (PROX) reaction in the presence of a H{sub 2}-rich gas stream. The variances in these metal foams' activity and selectivity were much larger than expected. Other structured supports with 5 wt% Pt, 0-1 wt% Fe weight loading were also examined. A theory for this phenomenon states that even though these structured supports have a similar nominal catalyst weight loading, only a certain percentage of the Pt/Fe catalyst is exposed on the surface as an active site for CO adsorption. We will use two techniques, pulse chemisorption and temperature programmed desorption (TPD), to characterize our structured supports. Active metal count, metal dispersion, and other calculations will help clarify the causes for the activity and selectivity variations between the supports. Results on ceramic monoliths show that a higher Fe loading yields a lower dispersion, potentially because of Fe inhibition of the Pt surface for CO adsorption. This theory is used to explain the reason for activity and selectivity differences for varying ppi and {rho} metal foams; less active and selective metal foams have a lower Fe loading, which justifies their higher metal dispersion. Data on the CO desorption temperature and average metal crystallite size for TPD are also collected.

Paul Chin; George W. Roberts; James J. Spivey

2003-12-31T23:59:59.000Z

357

Tunable hydrogen storage in magnesium–transition metal compounds: First-principles calculations  

Science Journals Connector (OSTI)

Magnesium dihydride (MgH2) stores 7.7?wt?% hydrogen but it suffers from a high thermodynamic stability and slow (de)hydrogenation kinetics. Alloying Mg with lightweight transition metals (TM) (=Sc,Ti,V,Cr) aims at improving the thermodynamic and kinetic properties. We study the structure and stability of MgxTM1?xH2 compounds, x=[0–1], by first-principles calculations at the level of density functional theory. We find that the experimentally observed sharp decrease in hydrogenation rates for x?0.8 correlates with a phase transition of MgxTM1?xH2 from a fluorite to a rutile phase. The stability of these compounds decreases along the series Sc, Ti, V, and Cr. Varying the TM and the composition x, the formation enthalpy of MgxTM1?xH2 can be tuned over the substantial range of 0–2 eV/f.u. Assuming however that the alloy MgxTM1?x does not decompose upon dehydrogenation, the enthalpy associated with reversible hydrogenation of compounds with a high magnesium content (x=0.75) is close to that of pure Mg.

Süleyman Er; Dhirendra Tiwari; Gilles A. de Wijs; Geert Brocks

2009-01-09T23:59:59.000Z

358

Magnetic properties of transition metal doped AlN nanosheet: First-principle studies  

SciTech Connect (OSTI)

We carry out our first-principles calculations within density functional theory to study the 3d transition metal (TM) doped AlN nanosheets. The calculated results indicate that a stoichiometric AlN nanosheet is graphene-like structure and nonmagnetic. The TM impurities can induce magnetic moments, localized mainly on the 3d TM atoms and neighboring N atoms. Our calculated results of TM-doped nanosheet systems indicate a strong interaction between 3d orbit of TM atom and the 2p orbit of N atoms. In addition, the Mn- and Ni-doped AlN nanosheet with half-metal characters seems to be good candidates for spintronic applications. When substituting two Al atoms, the relative energies of the states between ferromagnetic and antiferromagnetic coupling are investigated sufficiently. The exchange coupling of Co- and Ni-doped AlN nanosheets exhibits a transformation with different distances of two TM atoms and that of Cr-, Mn-, and Fe-doped AlN nanosheets is not changed.

Shi, Changmin; Qin, Hongwei, E-mail: qin-hw@vip.163.com; Zhang, Yongjia; Hu, Jifan; Ju, Lin [School of Physics, State Key Laboratory for Crystal Materials, Shandong University, Jinan 250100 (China)

2014-02-07T23:59:59.000Z

359

Inelastic exchange scattering in electron-energy-loss spectroscopy: Localized excitations in transition-metal and rare-earth systems  

Science Journals Connector (OSTI)

Cross sections for quasiatomic excitation by exchange scattering of electrons are calculated in the Born-Ochkur approximation for 3p-3d and 3d-3d transitions in transition-metal systems, and for 4d-4f and 4f-4f transitions in rare earths. The energy dependence of the spin polarization of 3p-3d and 4d-4f losses in reflection electron-energy-loss spectroscopy from ferromagnetic surfaces involves a balance of small-angle spin-dependent inelastic processes accompanied by a high-angle elastic scattering, and large-angle spin-flip exchange scattering without the need for elastic scattering. Both 3d-3d excitations, e.g., in transition-metal compounds, and 4f-4f excitations in rare earths involve spin-flip transitions whose scattering amplitudes g fall off with momentum transfer q such that the full width at half maximum q1/2 (in a.u.) is given by q1/2?rnl??2, where ?rnl? is the expectation value of r for the 3d or 4f electron. The angular width of the spin-flip differential cross section is then much greater than for dipole transitions, a pattern that helps to account for how these intra-atomic transitions compete with dipole processes for primary energies in excess of 100 eV.

S. J. Porter; J. A. D. Matthew; R. J. Leggott

1994-07-15T23:59:59.000Z

360

Composition-tailored synthesis of gradient transition metal precursor particles for lithium-ion battery cathode materials.  

SciTech Connect (OSTI)

We report the tailored synthesis of particles with internal gradients in transition metal composition aided by the use of a general process model. Tailored synthesis of transition metal particles was achieved using a coprecipitation reaction with tunable control over the process conditions. Gradients in the internal composition of the particles was monitored and confirmed experimentally by analysis of particles collected during regularly timed intervals. Particles collected from the reactor at the end of the process were used as the precursor material for the solid-state synthesis of Li{sub 1.2}(Mn{sub 0.62}Ni{sub 0.38}){sub 0.8}O{sub 2}, which was electrochemically evaluated as the active cathode material in a lithium battery. The Li{sub 1.2}(Mn{sub 0.62}Ni{sub 0.38}){sub 0.8}O{sub 2} material was the first example of a structurally integrated multiphase material with a tailored internal gradient in relative transition metal composition as the active cathode material in a lithium-ion battery. We believe our general synthesis strategy may be applied to produce a variety of new cathode materials with tunable interior, surface, and overall relative transition metal compositions.

Koenig, G. M.; Belharouak, I.; Deng, H.; Amine, K.; Sun, Y. K. (Chemical Sciences and Engineering Division)

2011-04-12T23:59:59.000Z

Note: This page contains sample records for the topic "transition metal oxide" 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

3d transition metal impurities in aluminum: A first-principles study M. Mantina, S. L. Shang, Y. Wang, L. Q. Chen, and Z. K. Liu  

E-Print Network [OSTI]

3d transition metal impurities in aluminum: A first-principles study M. Mantina, S. L. Shang, Y September 2009; published 18 November 2009 In this work, appropriate description of interactions of 3d transition metals in aluminum Al-3d is attained from first-principles using LDA+U potential within density

Chen, Long-Qing

362

Atomic polar tensors and acid-base properties of metal-oxide building blocks  

SciTech Connect (OSTI)

The sensitivity of the atomic polar tensor to compositional substituents is reported for the alkali silicate series. Rotational invariants, effective atomic charge (GAPT) and charge normalized anisotropy and dipole ({alpha}{sub n} and {gamma}{sub n}) are used to characterize the charge distribution and chemical environment of the atomic sites. Comparison of {alpha}{sub n} and {gamma}{sub n} with a series of known Bronsted and Lewis acids and bases suggests that these rotational invariants may act as indicators for metal-oxide site acidities. Basis set and electron correlation particularly affect the determined effective charge, but show minimal effect on {alpha} and {gamma} quantities.

Ferris, K.F.

1993-02-01T23:59:59.000Z

363

Atomic polar tensors and acid-base properties of metal-oxide building blocks  

SciTech Connect (OSTI)

The sensitivity of the atomic polar tensor to compositional substituents is reported for the alkali silicate series. Rotational invariants, effective atomic charge (GAPT) and charge normalized anisotropy and dipole ([alpha][sub n] and [gamma][sub n]) are used to characterize the charge distribution and chemical environment of the atomic sites. Comparison of [alpha][sub n] and [gamma][sub n] with a series of known Bronsted and Lewis acids and bases suggests that these rotational invariants may act as indicators for metal-oxide site acidities. Basis set and electron correlation particularly affect the determined effective charge, but show minimal effect on [alpha] and [gamma] quantities.

Ferris, K.F.

1993-02-01T23:59:59.000Z

364

REFORMULATION OF COAL-DERIVED TRANSPORTATION FUELS: SELECTIVE OXIDATION OF CARBON MONOXIDE ON METAL FOAM CATALYSTS  

SciTech Connect (OSTI)

Hydrocarbon fuels must be reformed in a series of steps to provide hydrogen for use in proton exchange membrane fuel cells (PEMFCs). Preferential oxidation (PROX) is one method to reduce the CO concentration to less than 10 ppm in the presence of {approx}40% H{sub 2}, CO{sub 2}, and steam. This will prevent CO poisoning of the PEMFC anode. Structured supports, such as ceramic monoliths, can be used for the PROX reaction. Alternatively, metal foams offer a number of advantages over the traditional ceramic monolith.

Paul Chin; Xiaolei Sun; George W. Roberts; Amornmart Sirijarhuphan; Sourabh Pansare; James G. Goodwin Jr; Richard W. Rice; James J. Spivey

2005-06-01T23:59:59.000Z

365

Synchronization of pairwise-coupled, identical, relaxation oscillators based on metal-insulator phase transition devices: A Model Study  

E-Print Network [OSTI]

Computing with networks of synchronous oscillators has attracted wide-spread attention as novel materials and device topologies have enabled realization of compact, scalable and low-power coupled oscillatory systems. Of particular interest are compact and low-power relaxation oscillators that have been recently demonstrated using MIT (metal- insulator-transition) devices using properties of correlated oxides. This paper presents an analysis of the dynamics and synchronization of a system of two such identical coupled relaxation oscillators implemented with MIT devices. We focus on two implementations of the oscillator: (a) a D-D configuration where complementary MIT devices (D) are connected in series to provide oscillations and (b) a D-R configuration where it is composed of a resistor (R) in series with a voltage-triggered state changing MIT device (D). The MIT device acts like a hysteresis resistor with different resistances in the two different states. The synchronization dynamics of such a system has been analyzed with purely charge based coupling using a resistive (Rc) and a capacitive (Cc) element in parallel. It is shown that in a D-D configuration symmetric, identical and capacitively coupled relaxation oscillator system synchronizes to an anti-phase locking state, whereas when coupled resistively the system locks in phase. Further, we demonstrate that for certain range of values of Rc and Cc, a bistable system is possible which can have potential applications in associative computing. In D-R configuration, we demonstrate the existence of rich dynamics including non-monotonic flows and complex phase relationship governed by the ratios of the coupling impedance. Finally, the developed theoretical formulations have been shown to explain experimentally measured waveforms of such pairwise coupled relaxation oscillators.

Abhinav Parihar; Nikhil Shukla; Suman Datta; Arijit Raychowdhury

2014-08-11T23:59:59.000Z

366

A unified view of coherent and incoherent dihydrogen exchange in transition metal hydrides by nuclear resonance and inelastic neutron scattering  

SciTech Connect (OSTI)

In this paper a unified view of coherent and incoherent dihydrogen exchange in transition metal hydrides by nuclear magnetic resonance (NMR) and inelastic neutron scattering (INS) is presented. It is shown that both exchange processes coexist i.e. do not transform into each other although they may dominate the spectra in different temperature ranges. This superposition is the consequence of the incorporation of the tunnel frequency J of the coherent process into the nuclear two-spin hamiltonian of hydrogen pairs which allows to treat the problem using the well known density matrix theory of NMR line-shapes developed by Alexander and Binsch. It is shown that this theory can also be used to predict the line-shapes of the rotational tunneling transitions observed in the INS spectra of transition metal dihydrogen complexes and that both NMR and INS spectra depend on similar parameters.

Limbach, H.H.; Ulrich, S.; Buntkowsky, G. [Freie Univ. Berlin (Germany). Inst. fuer Organische Chemie; Sabo-Etienne, S.; Chaudret, B. [Toulouse-3 Univ., 31 (France). Lab. de Chimie de Coordination du C.N.R.S.; Kubas, G.J.; Eckert, J. [Los Alamos National Lab., NM (United States)

1995-08-12T23:59:59.000Z

367

Effect of pre-oxidation and environmental aging on the seal strength of a novel high-temperature solid oxide fuel cell (SOFC) sealing glass with metallic interconnect  

SciTech Connect (OSTI)

A novel high-temperature alkaline-earth silicate sealing glass was developed for solid oxide fuel cell (SOFC) applications. The glass was used to join two ferritic stainless steel coupons for strength evaluation. The steel coupons were pre-oxidized at elevated temperatures to promote thick oxide layers to simulate long-term exposure conditions. In addition, seals to as-received metal coupons were also tested after aging in oxidizing or reducing environments to simulate the actual SOFC environment. Room temperature tensile testing showed strength degradation when using pre-oxidized coupons, and more extensive degradation after aging in air. Fracture surface and microstructural analysis confirmed that the cause of degradation was formation of SrCrO4 at the outer sealing edges exposed to air.

Chou, Y. S.; Stevenson, Jeffry W.; Singh, Prabhakar

2008-09-15T23:59:59.000Z

368

Effect of hydrogen sulfide on chemical looping combustion of coal-derived synthesis gas over bentonite-supported metal-oxide oxygen carriers  

SciTech Connect (OSTI)

The effect of hydrogen sulfide (H{sub 2}S) on the chemical looping combustion of coal-derived synthesis gas with bentonite-supported metal oxides - such as iron oxide, nickel oxide, manganese oxide, and copper oxide - was investigated by thermogravimetric analysis, mass spectrometry, and X-ray photoelectron spectroscopy (XPS). During the reaction with synthesis gas containing H{sub 2}S, metal-oxide oxygen carriers were first reduced by carbon monoxide and hydrogen, and then interacted with H{sub 2}S to form metal sulfide, which resulted in a weight gain during the reduction/sulfidation step. The reduced/sulfurized compounds could be regenerated to form sulfur dioxide and oxides during the oxidation reaction with air. The reduction/oxidation capacities of iron oxide and nickel oxide were not affected by the presence of H{sub 2}S, but both manganese oxide and copper oxide showed decreased reduction/oxidation capacities. However, the rates of reduction and oxidation decreased in the presence of H{sub 2}S for all four metal oxides.

Tian, H.J.; Simonyi, T.; Poston, J.; Siriwardane, R. [US DOE, Morgantown, WV (United States). National Energy Technology Laboratory

2009-09-15T23:59:59.000Z

369

Water growth on metals and oxides: binding, dissociation and role of hydroxyl groups  

SciTech Connect (OSTI)

The authors discuss the role of the presence of dangling H bonds from water or from surface hydroxyl species on the wetting behavior of surfaces. Using Scanning Tunneling and Atomic Force Microscopies, and Photoelectron Spectroscopy, they have examined a variety of surfaces, including mica, oxides, and pure metals. They find that in all cases, the availability of free, dangling H-bonds at the surface is crucial for the subsequent growth of wetting water films. In the case of mica electrostatic forces and H-bonding to surface O atoms determine the water orientation in the first layer and also in subsequent layers with a strong influence in its wetting characteristics. In the case of oxides like TiO{sub 2}, Cu{sub 2}O, SiO{sub 2} and Al{sub 2}O{sub 3}, surface hydroxyls form readily on defects upon exposure to water vapor and help nucleate the subsequent growth of molecular water films. On pure metals, such as Pt, Pd, and Ru, the structure of the first water layer and whether or not it exhibits dangling H bonds is again crucial. Dangling H-bonds are provided by molecules with their plane oriented vertically, or by OH groups formed by the partial dissociation of water. By tying the two II atoms of the water molecules into strong H-bonds with pre-adsorbed O on Ru can also quench the wettability of the surface.

Salmeron, M.; Bluhm, H.; Tatarkhanov, M.; Ketteler, G.; Shimizu, T.K.; Mugarza, A.; Deng, Xingyi; Herranz, T.; Yamamoto, S.; Nilsson, A.

2008-09-01T23:59:59.000Z

370

Ab initio study of lithium intercalation in metal oxides and metal dichalcogenides M. K. Aydinol, A. F. Kohan, and G. Ceder  

E-Print Network [OSTI]

-metal-oxides due to their application potential as rechargeable battery electrodes1 and electrochromic displays.2. In electrochromic applications, band filling is used to adjust the electronic and optical properties.3 Figure 1-potential difference between cathode and anode is desirable as this leads to a high OCV. For electrochromic

Ceder, Gerbrand

371

First-principles study of thin magnetic transition-metal silicide films on Si(001) Hua Wu, Peter Kratzer, and Matthias Scheffler  

E-Print Network [OSTI]

First-principles study of thin magnetic transition-metal silicide films on Si(001) Hua Wu, Peter of ferromag- netic FM materials have been suggested for the fabrication of metal/semiconductor heterojunctions s : 75.70. i, 73.20.At, 68.35.Md I. INTRODUCTION Metal-semiconductor heterojunctions have received much

372

Extending surface-enhanced Raman spectroscopy to transition-metal surfaces: carbon monoxide adsorption and electrooxidation on platinum- and palladium-coated gold electrodes  

SciTech Connect (OSTI)

Thin (ca. one to three monolayers) films of platinum and palladium electrodeposited on electrochemically roughened gold are observed to yield surface-enhanced Raman (SER) spectra for adsorbed carbon monoxide. The major vibrational band(s) on these surfaces are diagnosed from their frequencies as arising from C-O stretching vibrations, nu/sub CO/ bound to the transition-metal overlayers rather than to residual gold sites. The observed SFR nu/sub CO/ frequencies are closely similar to (within ca. 10 cm/sup -1/ of) those obtained for these systems from potential-difference infrared (PDIR) spectra. The major SERS and PDIR nu/sub CO/ features for the platinum and palladium surfaces appear at 2060-2090 and 1965-1985 cm/sup -1/, respectively, consistent with the presence of terminal and bridging CO on these two electrodes. The infrared as well as electrochemical properties of these systems are closely similar to those for the corresponding polycrystalline bulk electrodes. A difference between the SER- and IR-active adsorbed CO, however, is that the former undergoes electrooxidation on both surfaces at 0.2-0.3 V higher overpotentials than the latter form. Examination of the potential-dependent SERS bands for metal oxide vibrations, nu/sub PtO/, on the platinum surface shows that the electrooxidation potential for the SERS-active adsorbed CO coincides with that for the appearance of the nu/sub PtO/ band. Some broader implications to the utilization of SERS for examining transition-metal surfaces are pointed out.

Leung, L.W.H.; Weaver, M.J.

1987-08-19T23:59:59.000Z

373

E-Print Network 3.0 - apparent metal-insulator transition Sample...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

mathmatiques Collection: Mathematics 51 Superconductor-Correlated metal-Superconductor Josephson junctions Summary: -potential approximation which displays a metal-insulator...

374

Disposition of Uranium -233 (sup 233U) in Plutonium Metal and Oxide at the Rocky Flats Environmental Technology Site  

SciTech Connect (OSTI)

This report documents the position that the concentration of Uranium-233 ({sup 233}U) in plutonium metal and oxide currently stored at the DOE Rocky Flats Environmental Technology Site (RFETS) is well below the maximum permissible stabilization, packaging, shipping and storage limits. The {sup 233}U stabilization, packaging and storage limit is 0.5 weight percent (wt%), which is also the shipping limit maximum. These two plutonium products (metal and oxide) are scheduled for processing through the Building 371 Plutonium Stabilization and Packaging System (PuSPS). This justification is supported by written technical reports, personnel interviews, and nuclear material inventories, as compiled in the ''History of Uranium-233 ({sup 233}U) Processing at the Rocky Flats Plant In Support of the RFETS Acceptable Knowledge Program'' RS-090-056, April 1, 1999. Relevant data from this report is summarized for application to the PuSPS metal and oxide processing campaigns.

Freiboth, Cameron J.; Gibbs, Frank E.

2000-03-01T23:59:59.000Z

375

Gate Metal-Induced Diffusion and Interface Reactions in Hf Oxide Films on Si  

SciTech Connect (OSTI)

When metal electrodes are deposited on a high-{kappa} metal-oxide/SiO{sub 2}/Si stack, chemical interactions may occur both at the metal/high-{kappa} and the high-{kappa}/Si interfaces, causing changes in electrical performance. We report here results from medium energy ion scattering (MEIS) and x-ray photoelectron (XPS) studies of oxygen and silicon transport and interfacial layer reactions in multilayer gate stacks. Our results show that Ti deposition on HfO{sub 2}/SiO{sub 2}/Si stacks causes reduction of the SiO{sub 2} interfacial layer and (to a lesser extent) the HfO{sub 2} layer. Silicon atoms initially present in the interfacial SiO{sub 2} layer incorporate into the bottom of the high-{kappa} layer. Some evidence for titanium-silicon interdiffusion through the high-{kappa} film in the presence of a titanium gate in crystalline HfO{sub 2} films is also reported.

Goncharova, Lyudmila V.; Dalponte, Mateus; Celik, Ozgur; Garfunkel, Eric; Gustafsson, Torgny [Departments of Physics and Chemistry, and Laboratory for Surface Modification, Rutgers University, Piscataway, NJ 08854 (United States); Lysaght, Pat S.; Bersuker, Gennadi I. [Sematech, Austin, Texas 78741 (United States)

2007-09-26T23:59:59.000Z

376

Method and apparatus for preparation of spherical metal carbonates and lithium metal oxides for lithium rechargeable batteries  

DOE Patents [OSTI]

A number of materials with the composition Li.sub.1+xNi.sub..alpha.Mn.sub..beta.Co.sub..gamma.M'.sub..delta.O.sub.2-- zF.sub.z (M'=Mg,Zn,Al,Ga,B,Zr,Ti) for use with rechargeable batteries, wherein x is between about 0 and 0.3, .alpha. is between about 0.2 and 0.6, .beta. is between about 0.2 and 0.6, .gamma. is between about 0 and 0.3, .delta. is between about 0 and 0.15, and z is between about 0 and 0.2. Adding the above metal and fluorine dopants affects capacity, impedance, and stability of the layered oxide structure during electrochemical cycling. Another aspect of the invention includes materials with the composition Li.sub.1+xNi.sub..alpha.Co.sub..beta.Mn.sub..gamma.M'.sub..delta.O.sub.yF- .sub.z (M'=Mg,Zn,Al,Ga,B,Zr,Ti), where the x is between 0 and 0.2, the .alpha. between 0 and 1, the .beta. between 0 and 1, the .gamma. between 0 and 2, the .delta. between about 0 and about 0.2, the y is between 2 and 4, and the z is between 0 and 0.5.

Kang, Sun-Ho (Naperville, IL); Amine, Khalil (Downers Grove, IL)

2008-10-14T23:59:59.000Z

377

Kh a 1,2 hyperesatellites of 3d transition metals and their photoexcitation energy dependence.  

SciTech Connect (OSTI)

Hollow atoms in which the K shell is empty while the outer shells are populated allow studying a variety of important and unusual properties of atoms. The diagram x-ray emission lines of such atoms, the K{sup h} {alpha}{sub 1,2} hypersatellites (HSs), were measured for the 3d transition metals, Z = 23-30, with a high energy resolution using photoexcitation by monochromatized synchrotron radiation. Good agreement with ab initio relativistic multiconfigurational Dirac-Fock calculations was found. The measured HS intensity variation with the excitation energy yields accurate values for the excitation thresholds, excludes contributions from shake-up processes, and indicates domination near threshold of a nonshake process. The Z variation of the HS shifts from the diagram line K{alpha}{sub 1,2}, the K{sup h}{alpha}{sub 1}-K{sup h}{alpha}{sub 2} splitting, and the K{sup h}{alpha}{sub 1}/K{sup h}{alpha}{sub 2} intensity ratio, derived from the measurements, are also discussed with a particular emphasis on the QED corrections and Breit interaction.

Diamant, R.; Kao, C.; Huotari, S; Hamalainen, K; Sharon, R; Deutsch, M.

2009-06-25T23:59:59.000Z

378

Gas-phase chemical reactions of transition metal clusters with simple molecules  

SciTech Connect (OSTI)

Chemical reactions of isolated transition metal clusters are studied in a laser-vaporization cluster source coupled to a continuous-flow reactor. Detection of reaction products is via laser ionization and time-of-flight mass spectrometry. Experimental probes that have been developed include: (1) kinetics measurements, in which the disappearance of bare cluster signal with increasing reagent gas flow is used to determine absolute reaction rate constants for the addition of the first adsorbate molecule; (2) product composition measurements, in which inferences as to cluster structure and the nature of surface binding sites are derived by determining the total number of adsorbates the clusters can accommodate; (3) laser-induced desorption experiments, from which adsorbate binding energies can be derived; and (4) the observation of actual chemical reactions on cluster surfaces, such as hydrogen/deuterium exchange or adsorbate photochemistry. In addition, a new experimental procedure has been developed that, in a single series of measurements, provides measures of the first three parameters listed above. A review is given of earlier studies of the reaction of iron clusters with hydrogen. More recent results on the reaction of iron clusters with ammonia, and the reaction of ammoniated iron clusters with hydrogen, are also presented.

Riley, S.J.; Parks, E.K.

1986-01-01T23:59:59.000Z

379

First-principles prediction of magnetic superatoms in 4d-transition-metal-doped magnesium clusters  

SciTech Connect (OSTI)

We theoretically predict magnetic superatoms in the 4d-transition-metal-doped Mg{sub 8} clusters using a spin-polarized density functional theory method. We demonstrate that TcMg{sub 8} is highly energetically stable in both structure and magnetic states, and identify it as a magnetic superatom with a magnetic moment as large as 5 ?{sub B}. The magnetic TcMg{sub 8} with 23 valence electrons has a configuration of 1S{sup 2}1P{sup 6}1D{sup 10} closed shell and 2S{sup 1}2D{sup 4} open shell, complying with Hund's rule similar to the single atom. We elucidate the formation mechanism of the magnetic TcMg{sub 8} superatom based on the detailed analysis of molecular orbitals, and attribute it to the large exchange interaction and moderate crystal field effect. Finally, we predict that the magnetic TcMg{sub 8} may exhibit semiconductor-like property with spin polarization characteristics.

Ge, Gui-Xian [National Laboratory of Solid State Microstructures, and Department of Physics, Nanjing University, Nanjing 210093 (China) [National Laboratory of Solid State Microstructures, and Department of Physics, Nanjing University, Nanjing 210093 (China); Key Laboratory of Ecophysics and Department of Physics, College of Science, Shihezi University, Xinjiang 832003 (China); Han, Yan; Wan, Jian-Guo, E-mail: wanjg@nju.edu.cn; Wang, Guang-Hou [National Laboratory of Solid State Microstructures, and Department of Physics, Nanjing University, Nanjing 210093 (China)] [National Laboratory of Solid State Microstructures, and Department of Physics, Nanjing University, Nanjing 210093 (China); Zhao, Ji-Jun [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Dalian University of Technology, Ministry of Education, Dalian 116024 (China)] [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Dalian University of Technology, Ministry of Education, Dalian 116024 (China)

2013-11-07T23:59:59.000Z

380

Durability study of transition metal based non-precious cathode in PEFC  

SciTech Connect (OSTI)

This paper focuses on performance durability of newly developed polyaniline (PANI)-derived non-precious cathode catalyst, whose high oxygen-reduction activity was verified in electrochemical and fuel cell testing, exhibiting onset and half-wave potential (E{sup 1/2}) of oxygen reduction at 0.90 V and 0.77 V, respectively, as well as an insignificant H{sub 2}O{sub 2} yields below 1%. It was found catalyst durability in fuel cell life tests is greatly dependent on the catalyst synthesis including nitrogen precursors, employed transition metals, and supporting materials. Importantly, the working voltages in fuel cell testing have a profound impact on the stability, which much more stable performance can be observed at lower voltage such as 0.4 V when compared with higher voltage, 0.6 V. Preliminary physical and electrochemical characterization present to provide insight into the origin of the possible degradation mechanism for the non-precious active sites.

Wu, Gang [Los Alamos National Laboratory; Zelenay, Piotr [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "transition metal oxide" 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.


381

Transition metal ion-assisted photochemical generation of alkyl halides and hydrocarbons from carboxylic acids  

SciTech Connect (OSTI)

Near-UV photolysis of aqueous solutions of propionic acid and aqueous Fe3+ in the absence of oxygen generates a mixture of hydrocarbons (ethane, ethylene and butane), carbon dioxide, and Fe2+. The reaction becomes mildly catalytic (about five turnovers) in the presence of oxygen which converts a portion of alkyl radicals to oxidizing intermediates that reoxidize Fe2+. The photochemistry in the presence of halide ions (X? = Cl?, Br?) generates ethyl halides via halogen atom abstraction from FeXn3?n by ethyl radicals. Near-quantitative yields of C2H5X are obtained at ?0.05 M X?. Competition experiments with Co(NH3)5Br2+ provided kinetic data for the reaction of ethyl radicals with FeCl2+ (k = (4.0 ± 0.5) × 106 M?1 s?1) and with FeBr2+ (k = (3.0 ± 0.5) × 107 M?1 s?1). Photochemical decarboxylation of propionic acid in the presence of Cu2+ generates ethylene and Cu+. Longer-chain acids also yield alpha olefins as exclusive products. These reactions become catalytic under constant purge with oxygen which plays a dual role. It reoxidizes Cu+ to Cu2+, and removes gaseous olefins to prevent accumulation of Cu+(olefin) complexes and depletion of Cu2+. The results underscore the profound effect that the choice of metal ions, the medium, and reaction conditions exert on the photochemistry of carboxylic acids.

Carraher, Jack; Pestovsky, Oleg; Bakac, Andreja

2012-03-14T23:59:59.000Z

382

Picosecond soft x-ray absorption measurement of the photoinduced insulator-to-metal transition in VO2  

Science Journals Connector (OSTI)

We directly measure the photoinduced insulator-to-metal transition in VO2 using time-resolved near-edge x-ray absorption. Picosecond pulses of synchrotron radiation are used to detect the redshift in the vanadium L3 edge at 516 eV, which is associated with the transient collapse of the low-temperature band gap. We identify a two-component temporal response, corresponding to an ultrafast transformation over a 50 nm surface layer, followed by 40 m/s thermal growth of the metallic phase into the bulk.

A. Cavalleri, H. H. W. Chong, S. Fourmaux, T. E. Glover, P. A. Heimann, J. C. Kieffer, B. S. Mun, H. A. Padmore, and R. W. Schoenlein

2004-04-28T23:59:59.000Z

383

Strong segregation gettering of transition metals by implantation-formed cavities and boron-silicide precipitates in silicon  

SciTech Connect (OSTI)

We have mechanistically and quantitatively characterized the binding of transition-metal impurities in Si to cavities formed by He implantation and to B-Si precipitates resulting from B implantation. Both sinks are inferred to act by the segregation of metal atoms to pre-existing low-energy sites, namely surface chemisorption sites in the case of cavities and bulk solution sites in the case of the B-Si phase. These gettering processes exhibit large binding energies, and they are predicted to remain active for arbitrarily small initial impurity concentrations as a result of the segregation mechanisms. Both appear promising for gettering in Si devices.

Myers, S.M.; Petersen, G.A.; Follstaedt, D.M.; Headley, T.J. [and others

1996-06-01T23:59:59.000Z

384

Porphyrins and metal complexes thereof having haloalkyl side chains  

DOE Patents [OSTI]

Transition metal complexes of meso-haloalkylporphyrins, wherein the haloalkyl groups contain 2 to 8 carbon atoms have been found to be highly effective catalysts for oxidation of alkanes and for the decomposition of hydroperoxides. 7 figs.

Wijesekera, T.; Lyons, J.E.; Ellis, P.E. Jr.; Bhinde, M.V.

1997-03-04T23:59:59.000Z

385

Porphyrins and metal complexes thereof having haloalkyl side chains  

DOE Patents [OSTI]

Transition metal complexes of meso-haloalkylporphyrins, wherein the haloalkyl groups contain 2 to 8 carbon atoms have been found to be highly effective catalysts for oxidation of alkanes and for the decomposition of hydroperoxides.

Wijesekera, Tilak (Glen Mills, PA); Lyons, James E. (Wallingford, PA); Ellis, Jr., Paul E. (Downingtown, PA); Bhinde, Manoj V. (Boothwyn, PA)

1997-01-01T23:59:59.000Z

386

Effect of hydrogen sulfide on chemical looping of coal-derived synthesis gas over bentonite-supported metal---oxide oxygen carriers  

SciTech Connect (OSTI)

The effect of hydrogen sulfide (H2S) on the chemical looping combustion of coal-derived synthesis gas with bentonite-supported metal oxidesssuch as iron oxide, nickel oxide, manganese oxide, and copper oxideswas investigated by thermogravimetric analysis, mass spectrometry, and X-ray photoelectron spectroscopy (XPS). During the reaction with synthesis gas containing H2S, metal-oxide oxygen carriers were first reduced by carbon monoxide and hydrogen, and then interacted with H2S to form metal sulfide, which resulted in a weight gain during the reduction/sulfidation step. The reduced/sulfurized compounds could be regenerated to form sulfur dioxide and oxides during the oxidation reaction with air. The reduction/oxidation capacities of iron oxide and nickel oxide were not affected by the presence of H2S, but both manganese oxide and copper oxide showed decreased reduction/oxidation capacities. However, the rates of reduction and oxidation decreased in the presence of H2S for all four metal oxides.

Tian, H.; Simonyi, T.; Poston, J.; Siriwardane, R.

2009-01-01T23:59:59.000Z

387

FINAL TECHNICAL REPORT Synthetic, Structural and Mechanistic Investigations of Olefin Polymerization Catalyzed by Early Transition Metal Compounds  

SciTech Connect (OSTI)

The goal of this project is to develop new catalysts and provide understanding of ligand effects on catalyst composition in order to guide development of superior catalyst systems for polymerization of olefins. Our group is designing and synthesizing new “LX2”,“pincer” type ligands and complexing early transition metals to afford precatalysts. In a collaboration with Hans Brintzinger from the University of Konstanz, we are also examining the structures of the components of catalyst systems obtained from reaction of zirconocene dichlorides with aluminum alkyls and aluminum hydrides. Such systems are currently used commercially to produce polyolefins, but the nature of the active and dormant species as well as the mechanisms of their interconversions are not understood. New information on catalyst design and performance may lead to new types of polymers and/or new chemical transformations between hydrocarbons and transition metal centers, ultimately contributing to the development of catalytic reactions for the production of fuels, commodity and polymeric materials.

Bercaw, John E. [California Institute of Technology

2014-05-23T23:59:59.000Z

388

WASP-36b: A New Transiting Planet around a Metal-poor G-dwarf, and an Investigation into Analyses Based on a Single Transit Light Curve  

Science Journals Connector (OSTI)

We report the discovery, from WASP and CORALIE, of a transiting exoplanet in a 1.54 day orbit. The host star, WASP-36, is a magnitude V = 12.7, metal-poor G2 dwarf ( K), with [Fe/H] =?0.26 ? 0.10. We determine the planet to have mass and radius, respectively, 2.30 ? 0.07 and 1.28 ? 0.03 times that of Jupiter. We have eight partial or complete transit light curves, from four different observatories, which allow us to investigate the potential effects on the fitted system parameters of using only a single light curve. We find that the solutions obtained by analyzing each of these light curves independently are consistent with our global fit to all the data, despite the apparent presence of correlated noise in at least two of the light curves.

A. M. S. Smith; D. R. Anderson; A. Collier Cameron; M. Gillon; C. Hellier; M. Lendl; P. F. L. Maxted; D. Queloz; B. Smalley; A. H. M. J. Triaud; R. G. West; S. C. C. Barros; E. Jehin; F. Pepe; D. Pollacco; D. Segransan; J. Southworth; R. A. Street; S. Udry

2012-01-01T23:59:59.000Z

389

Note: An ion source for alkali metal implantation beneath graphene and hexagonal boron nitride monolayers on transition metals  

SciTech Connect (OSTI)

The construction of an alkali-metal ion source is presented. It allows the acceleration of rubidium ions to an energy that enables the penetration through monolayers of graphene and hexagonal boron nitride. Rb atoms are sublimated from an alkali-metal dispenser. The ionization is obtained by surface ionization and desorption from a hot high work function surface. The ion current is easily controlled by the temperature of ionizer. Scanning Tunneling Microscopy measurements confirm ion implantation.

Lima, L. H. de [Instituto de Física “Gleb Wataghin”, Universidade Estadual de Campinas, 13083-859, Campinas, SP (Brazil)] [Instituto de Física “Gleb Wataghin”, Universidade Estadual de Campinas, 13083-859, Campinas, SP (Brazil); Cun, H. Y.; Hemmi, A.; Kälin, T.; Greber, T. [Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich (Switzerland)] [Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich (Switzerland)

2013-12-15T23:59:59.000Z

390

Semiconducting chalcogenide buffer layer for oxide heteroepitaxy on Si,,001...  

E-Print Network [OSTI]

controlled laminar growth of a crystalline transition metal oxide on Si 001 without SiOx or silicide/or silicides at the Si/oxide interface. Subnanometer buffer layers can prevent interface reac- tions while, also enables flexible strain relief. We observe nei- ther oxide nor silicide formation at the buried Si

Olmstead, Marjorie

391

HEU to LEU conversion and blending facility: Metal blending alternative to produce LEU oxide for disposal  

SciTech Connect (OSTI)

US DOE is examining options for disposing of surplus weapons-usable fissile materials and storage of all weapons-usable fissile materials. The nuclear material is converted to a form more proliferation- resistant than the original form. Blending HEU (highly enriched uranium) with less-enriched uranium to form LEU has been proposed as a disposition option. Five technologies are being assessed for blending HEU. This document provides data to be used in environmental impact analysis for the HEU-LEU disposition option that uses metal blending with an oxide waste product. It is divided into: mission and assumptions, conversion and blending facility descriptions, process descriptions and requirements, resource needs, employment needs, waste and emissions from plant, hazards discussion, and intersite transportation.

NONE

1995-09-01T23:59:59.000Z

392

Performance and degradation of metal-supported solid oxide fuel cells with impregnated electrodes  

Science Journals Connector (OSTI)

Abstract Metal-supported solid oxide fuel cells (MS-SOFCs) containing porous 430L stainless steel supports, YSZ electrolytes and porous YSZ cathode backbones are fabricated by tape casting, laminating and co-firing in a reducing atmosphere. Nano-scale Ni and La0.6Sr0.4Fe0.9Sc0.1O3?? (LSFSc) coatings are impregnated onto the internal surfaces of porous 430L and YSZ, acting as the anode and the cathode catalysts, respectively. The resulting MS-SOFCs exhibit maximum power densities of 193, 418, 636 and 907 mW cm?2 at 650, 700, 750 and 800 °C, respectively. Nevertheless, a continuous degradation in the fuel cell performance is observed at 650 °C and 0.7 V during a 200-h durability measurement. Possible degradation mechanisms were discussed in detail.

Yucun Zhou; Xianshuang Xin; Junliang Li; Xiaofeng Ye; Changrong Xia; Shaorong Wang; Zhongliang Zhan

2014-01-01T23:59:59.000Z

393

Corrosion and Protection of Metallic Interconnects in Solid Oxide Fuel Cells  

SciTech Connect (OSTI)

Energy security and increased concern over environmental protection have spurred a dramatic world-wide growth in research and development of fuel cells, which electrochemically convert incoming fuel into electricity with no or low pollution. Fuel cell technology has become increasingly attractive to a number of sectors, including utility, automotive, and defense industries. Among the various types of fuel cells, solid oxide fuel cells (SOFCs) operate at high temperature (typically 650-1,000 C) and have advantages in terms of high conversion efficiency and the flexibility of using hydrocarbon fuels, in addition to hydrogen. The high temperature operation, however, can lead to increased mass transport and interactions between the surrounding environment and components that are required to be stable during a lifetime of thousands of hours and up to hundreds of thermal cycles. For stacks with relatively low operating temperatures (<800 C), the interconnects that are used to electrically connect a number of cells in series are typically made from cost-effective metals or alloys. The metallic interconnects must demonstrate excellent stability in a very challenging environment during SOFC operation, as they are simultaneously exposed to both an oxidizing (air) environment on the cathode side and a reducing environment (hydrogen or a reformed hydrocarbon fuel) on the anode side. Other challenges include the fact that water vapor is likely to be present in both of these environments, and the fuel is likely to contain impurities, such as sulfides. Since the fuel is usually a reformed hydrocarbon fuel, such as natural gas, coal gas, biogas, gasoline, etc., the interconnect is exposed to a wet carbonaceous environment at the anode side. Finally, the interconnect must be stable towards any adjacent components, such as electrodes, seals and electrical contact materials, with which it is in physical contact.

Yang, Z Gary; Stevenson, Jeffry W.; Singh, Prabhakar

2007-12-09T23:59:59.000Z

394

Combined SIMS, AES, and XPS Investigations of Oxygen-Covered 3d Transition Metal Surfaces  

Science Journals Connector (OSTI)

The interaction of some 3d metals with oxygen in the monolayer range under UHV conditions has been investigated by quasisimultaneous static SIMS, static AES, and XPS. The combination ... metal-oxygen interaction ...

O. Ganschow; L. Wiedmann; A. Benninghoven

1979-01-01T23:59:59.000Z

395

High Charge State Ions Extracted from Metal Plasmas in the Transition Regime from Vacuum Spark to High Current Vacuum Arc  

SciTech Connect (OSTI)

Metal ions were extracted from pulsed discharge plasmas operating in the transition region between vacuum spark (transient high voltage of kV) and vacuum arc (arc voltage ~;; 20 V). At a peak current of about 4 kA, and with a pulse duration of 8 ?s, we observed mean ion charges states of about 6 for several cathode materials. In the case of platinum, the highest average charge state was 6.74 with ions of charge states as high as 10 present. For gold we found traces of charge state 11, with the highest average charge state of 7.25. At currents higher than 5 kA, non-metallic contaminations started to dominate the ion beam, preventing further enhancement of the metal charge states.

Yushkov, Georgy Yu.; Anders, A.

2008-06-19T23:59:59.000Z

396

AlGaN/GaN metal-oxide-semiconductor heterostructure field-effect transistors using barium strontium titanate  

E-Print Network [OSTI]

AlGaN/GaN metal-oxide-semiconductor heterostructure field-effect transistors using barium strontium-effect transistors have been formed by incorporating barium strontium titanate (BST) deposited by rf magnetron in increased leakage. Due to its large dielectric constant, barium strontium ti- tanate [Ba1-xSrxTiO3, (BST

York, Robert A.

397

High-temperature corrosion of metallic alloys in an oxidizing atmosphere containing NaCl  

SciTech Connect (OSTI)

A particular heat-exchanger application involved metallic alloys exposed to flue gases of an aluminum remelt furnace. Because the flue gases might contain NaCl and other halides, the corrosion behavior of the alloys was to be investigated. Planned direct exposure of candidate alloys to the flue gases, however, was not conducted because of premature termination of the project. Complementary laboratory testing was conducted on seven commercially available alloys and two nickel aluminides. These materials were exposed to an oxidizing atmosphere containing 0.06 wt % NaCl for 1100 h at 1000/degree/C. Most of the alloy exhibited grain-boundary attack, which resulted in complete oxidation of enveloped grains. The alloys Incoloy MA-956, Incoloy 800, Inconel 625, Inconel 601, Hastelloy X, Haynes 188, and nickel aluminide IC-50 were substantially more corroded than Alloy 214 and nickel aluminide IC-221. The latter two alloys, therefore, would probably be superior to the others in application involving flue gases containing NaCl. Strength fabricability, and weldability, which are briefly discussed, would also affect selection of materials. 8 refs., 12 figs., 5 tabs.

Federer, J.I.

1989-02-01T23:59:59.000Z

398

Metal-gate-induced reduction of the interfacial layer in Hf oxide gate stacks  

SciTech Connect (OSTI)

The properties of high-{kappa} metal oxide gate stacks are often determined in the final processing steps following dielectric deposition. We report here results from medium energy ion scattering and x-ray photoelectron spectroscopy studies of oxygen and silicon diffusion and interfacial layer reactions in multilayer gate stacks. Our results show that Ti metallization of HfO{sub 2}/SiO{sub 2}/Si stacks reduces the SiO{sub 2} interlayer and (to a more limited extent) the HfO{sub 2} layer. We find that Si atoms initially present in the interfacial SiO{sub 2} layer incorporate into the bottom of the high-{kappa} layer. Some evidence for Ti-Si interdiffusion through the high-{kappa} film in the presence of a Ti gate in the crystalline HfO{sub 2} films is also reported. This diffusion is likely to be related to defects in crystalline HfO{sub 2} films, such as grain boundaries. High-resolution transmission electron microscopy and corresponding electron energy loss spectroscopy scans show aggressive Ti-Si intermixing and oxygen diffusion to the outermost Ti layer, given high enough annealing temperature. Thermodynamic calculations show that the driving forces exist for some of the observed diffusion processes.

Goncharova, L. V.; Dalponte, M.; Gustafsson, T.; Celik, O.; Garfunkel, E.; Lysaght, P. S.; Bersuker, G. [Department of Physics and Astronomy, and Laboratory for Surface Modification, Rutgers University, 136 Frelinghuysen Rd., Piscataway, New Jersey 08854 (United States); Department of Chemistry and Chemical Biology, and Laboratory for Surface Modification, Rutgers University, 610 Taylor Rd., Piscataway, New Jersey 08854 (United States); SEMATECH, 2705 Montopolis Dr., Austin, Texas 78741 (United States)

2007-03-15T23:59:59.000Z

399

INFLUENCE OF OXIDE GROWTH AND METAL CREEP ON STRAIN DEVELOPMENT IN THE STEAM-SIDE OXIDE IN BOILER TUBES  

SciTech Connect (OSTI)

This effort is concerned with developing a quantitative description of the exfoliation behavior of oxide scales grown inside steam tubes in a pressure boiler. Consideration of the development of stress/strain in growing oxides has included expansion mismatch-induced strains during thermal cycling as well as inelastic mechanical effects from oxide/alloy creep phenomena and volume change from oxide growth. The magnitude of the parameters used has been closely matched to actual boiler operating practice. The creep model used was validated against published data. Representation of oxide growth-induced strain was found to be a difficult challenge because the processes involved are not fully understood. In addition to the traditional uniaxial (radial) and dilatational models, lateral growth models are discussed in the context of experimentally-derived criteria, such as the level of elastic strains involved in oxide exfoliation. It was found that strain variation in the oxide cannot be neglected.

Sabau, Adrian S [ORNL; Wright, Ian G [ORNL

2010-01-01T23:59:59.000Z

400

Formation and fragmentation of gas-phase ion-molecule complexes of transition-metal ions with organic molecules containing two functional groups  

Science Journals Connector (OSTI)

A mass spectrometer fast atom bombardment source has been used to synthesize, in the gas phase, the ion-molecule complexes of transition-metal ions (Ni+, CO+, Fe+, and Mn+) with ?- or ?-unsaturated alkenenitriles...

Lin-Zhi Chen; Jack M. Miller

1992-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "transition metal oxide" 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 influence of transition metal ions on the catalytic performance of Ru particles during the liquid phase hydrogenation of benzene to cyclohexene  

Science Journals Connector (OSTI)

The influence of some transition metal ions including Fe2+, Ni2+, Cr3+, Mn2+, Zn2+, Cd2+...on the catalytic performance of Ru particles during the liquid phase partial hydrogenation of benzene to cyclohexene was ...

Yixin Qu; Chengxuan Fang; Chengyang Qian…

2014-04-01T23:59:59.000Z

402

Ion-molecule reaction of alkanenitriles and transition-metal ions in the gas phase: A study on fragmentation mechanism of the adducts  

Science Journals Connector (OSTI)

Gas-phase ion-molecule reactions between transition-metal ions (Mn +, Fe+, Co+, ... +) and propionitri1e and acetonitrile were investigated. Ion-molecule adducts were prepared in a modified...

Lin-Zhi Chen; Jack M. Miller

1991-04-01T23:59:59.000Z

403

EPR identification of intrinsic and transition metal-related defects in ZnGeP2 and other IIIVV2 compounds  

E-Print Network [OSTI]

EPR identification of intrinsic and transition metal-related defects in ZnGeP2 and other II­IV­V2 studies of native defects and their transition energies, EPR investigations of isolated TMs on the two be obtained in a unique way by magnetic resonance methods, especially by electron paramagnetic resonance (EPR

Nabben, Reinhard

404

Promises and problems with metallic interconnects for reduced temperature solid oxide fuel cells  

E-Print Network [OSTI]

Symposium on Solid Oxide Fuel Cells (SOFC-VI) ed. S. C.FOR REDUCED TEMPERATURE SOLID OXIDE FUEL CELLS Peggy Y. Hou,for low temperature solid oxide fuel cell is discussed in

Hou, Peggy Y.; Huang, Keqin; Bakker, Wate T.

1999-01-01T23:59:59.000Z

405

Rapid thermal cycling of metal-supported solid oxide fuel cell membranes  

E-Print Network [OSTI]

effect of pressure on solid oxide fuel cell performance," inand flat plate solid oxide fuel cells," in Proceedings ofSymposium on Solid Oxide Fuel Cells. Electrochem. Soc. 1993,

Matus, Yuriy B.; De Jonghe, Lutgard C.; Jacobson, Craig P.; Visco, Steven J.

2004-01-01T23:59:59.000Z

406

E-Print Network 3.0 - alkali-transition metal borohydrides Sample...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

alkaline earth metal) ... Source: DOE Office of Energy Efficiency and Renewable Energy, Hydrogen, Fuel Cells and Infrastructure Technologies Program Collection: Energy Storage,...

407

Ab initio modeling of the two-dimensional energy landscape of screw dislocations in bcc transition metals  

Science Journals Connector (OSTI)

A density functional theory (DFT) study of the 1/2?111? screw dislocation was performed in the following body-centered cubic transition metals: V, Nb, Ta, Cr, Mo, W, and Fe. The energies of the easy, hard, and split core configurations, as well as the pathways between them, were investigated and used to generate the two-dimensional (2D) Peierls potential, i.e. the energy landscape seen by the dislocation as a function of its position in the (111) plane. In all investigated elements, the nondegenerate easy core is the minimum energy configuration, while the split core configuration, centered in the immediate vicinity of a ?111? atomic column, has a high energy near or above that of the hard core. This unexpected result yields 2D Peierls potentials very different from the usually assumed landscapes. The 2D Peierls potential in Fe differs from the other transition metals, with a monkey saddle instead of a local maximum located at the hard core. An estimation of the Peierls stress from the shape of the Peierls barrier is presented in all investigated metals. A strong group dependence of the core energy is also evidenced, related to the position of the Fermi level with respect to the minimum of the pseudogap of the electronic density of states.

L. Dezerald; Lisa Ventelon; E. Clouet; C. Denoual; D. Rodney; F. Willaime

2014-01-15T23:59:59.000Z

408

Solution-mediated strategies for synthesizing metal oxides, borates and phosphides using nanocrystals as reactive precursors  

E-Print Network [OSTI]

substrates can be transformed into their corresponding phosphides. Furthermore, this strategy is applicable towards the conversion of supported metal nanocrystals into metal phosphides. Supported metal phosphides are used as hydrotreating catalysts...

Henkes, Amanda Erin

2009-05-15T23:59:59.000Z

409

Oxidation of Metals, Vol. 61, Nos. 3/4, April 2004 ( 2004) Thermal Conductivity, Phase Stability, and Oxidation  

E-Print Network [OSTI]

, and Oxidation Resistance of Y3Al5O12 (YAG)/Y2O3­ZrO2 (YSZ) Thermal-Barrier Coatings Y. J. Su, R. W. Trice,# K oxidation resistance while maintaining low thermal conductivity and good phase stability. Padture) is proposed. The objective of this work is to quantify the effect of YAG on thermal resistance, long

Trice, Rodney W.

410

Calculations of the electronic structure and transitions of actinide metal hexafluorides  

Science Journals Connector (OSTI)

SCF?X??SW calculations are reported for the actinidemetal hexafluorides UF6 NpF6 and PuF6. Eigenvalues and charge densities analyzed according to angular momentum contributions within atomic spheres are given for the ground states and several transitions have been calculated using the electronic transition state concept.

Michael Boring; Harry G. Hecht

1978-01-01T23:59:59.000Z

411

Ultra-high vacuum fabrication and electrical characterization of environmentally sensitive metal oxide semiconductor capacitors  

SciTech Connect (OSTI)

We describe an integrated, ultra-high vacuum system for metal oxide semiconductor (MOS) device fabrication and characterization. Such a system is advantageous for electrical property measurements of electronic devices consisting of environmentally sensitive materials especially as device dimensions approach the nanoscale. Without exposure to atomosphere, MOS capacitors were fabricated by evaporating gate metal on molecular-beam-epitaxy (MBE) grown dielectrics on 3 inch-diameter substrates through a shadow mask in a UHV electrode-patterning chamber. The finished device is transferred in vacuum to an in-situ, UHV electrical characterization probe station that was designed with standard UHV coaxial feedthroughs and UHV-compatible, Kapton-insulated coaxial cable. The probe station also includes a heated sample stage that allows for annealing and measurements in a controlled ambient. We obtained excellent agreement between air-ambient ex-situ and in-situ probe station measurements utilizing a capacitor standard compatible with UHV based on single crystal sapphire as the dielectric. The measurements show less than 0.3 % dispersion for frequencies from 20 Hz to 1 MHz. We have successfully measured MOS capacitors and are sensitive to a density of interface states of 1x1010 states cm-2 eV-1. These measurements also show 0.5 % dispersion for measurement frequencies from 20 Hz to 1 kHz and less than 0.1 % from 1 kHz to 1 MHz. The integrated system presented here is one where complex, MBE-grown MOS heterostructures can be synthesized and tested rapidly to elucidate new field-effect-device physics and functionality.

Billman, Curt [Oak Ridge National Laboratory (ORNL); Walker, Frederick Joseph [ORNL

2007-01-01T23:59:59.000Z

412

Improved layered mixed transition metal oxides for Li-ion batteries  

E-Print Network [OSTI]

for rechargeable lithium batteries," Science 311(5763), 977-^ for Advanced Lithium-Ion Batteries," J. Electrochem. Soc.02 for lithium-ion batteries," Chem. Lett. , [3] Yabuuchi,

Doeff, Marca M.

2010-01-01T23:59:59.000Z

413

Improved layered mixed transition metal oxides for Li-ion batteries  

E-Print Network [OSTI]

out at the Stanford Synchroton Radiation Lightsource (SSRL).electrodes at the Stanford Synchroton Radiation Lightsourcein situ at the Stanford Synchroton Radiation Lightsource.

Doeff, Marca M.

2010-01-01T23:59:59.000Z

414

Thermodynamic Investigations of Lithium- and Manganese-Rich Transition Metal Oxides  

Broader source: Energy.gov [DOE]

2013 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Program Annual Merit Review and Peer Evaluation Meeting

415

The design of new ligands and transition metal compounds for the oxidation of organic compounds  

E-Print Network [OSTI]

..................................... 2 1.3 Epoxidation of ?,?-unsaturated carboxylic acids with catalytic sodium tungstate and hydrogen peroxide ........................................ 3 1.4 The Sharpless asymmetric epoxidation reaction.............................. 4 1.5... as Jacobsen?s catalyst 1-3 but generally only olefins with cis geometry or trisubstituted olefins are epoxidized in high ee. 6 Scheme 1.5. Salen ligands A crystallographic study of these catalysts provides valuable insight...

Grill, Joseph Michael

2009-06-02T23:59:59.000Z

416

Synthesis and characterization of nanostructured transition metal oxides for energy storage devices  

E-Print Network [OSTI]

insertion and is also electrochromic. These studies led toelectrode and as an electrochromic window. Lithium insertionone of the best inorganic electrochromic materials. [13] The

Kim, Jong Woung

2012-01-01T23:59:59.000Z

417

Synthesis and characterization of nanostructured transition metal oxides for energy storage devices  

E-Print Network [OSTI]

in Figure 3.1. Hydrothermal carbonization occurs throughassisted hydrothermal reaction promotes the carbonization ofhydrothermal process followed by thermal annealing for carbonization

Kim, Jong Woung

2012-01-01T23:59:59.000Z

418

Synthesis and characterization of nanostructured transition metal oxides for energy storage devices  

E-Print Network [OSTI]

the electrode material to provide either high energy or highhigh energy and power within the same basic material.materials having intercalation pseudocapacitance in order to obtain high energy

Kim, Jong Woung

2012-01-01T23:59:59.000Z

419

Promises and Challenges of Lithium- and Manganese-Rich Transition-Metal Layered-Oxide Cathodes  

Broader source: Energy.gov [DOE]

2013 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Program Annual Merit Review and Peer Evaluation Meeting

420

Transition Metal Oxide Nanoparticles Anchored Nanocarbon Hybrid Foam for High Performance Electrochemical Energy Storage Applications.  

E-Print Network [OSTI]

??In real life applications, supercapacitors (SCs) often can only be used as part of a hybrid system together with other high energy storage devices due… (more)

Wang, Wei

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "transition metal oxide" 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

Safety and core design of large liquid-metal cooled fast breeder reactors  

E-Print Network [OSTI]

Absorption Metal (Zr) Metal (Mo) Carbide Nitride Oxidef /? a k ? Metal (Zr) Metal (Mo) Carbide Nitride Oxide Table? a k ? Metal (Zr) Metal (Mo) Carbide Nitride Oxide CHAPTER

Qvist, Staffan Alexander

2013-01-01T23:59:59.000Z

422

High-Temperature Zirconia Oxygen Sensor with Sealed Metal/Metal...  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

High-Temperature Zirconia Oxygen Sensor with Sealed MetalMetal Oxide Internal Reference High-Temperature Zirconia Oxygen Sensor with Sealed MetalMetal Oxide Internal Reference...

423

Magnetism, structure, and charge correlation at a pressure-induced Mott-Hubbard insulator-metal transition  

SciTech Connect (OSTI)

We use synchrotron x-ray diffraction and electrical transport under pressure to probe both the magnetism and the structure of single-crystal NiS{sub 2} across its Mott-Hubbard transition. In the insulator, the low-temperature antiferromagnetic order results from superexchange among correlated electrons and couples to a (1/2, 1/2, 1/2) superlattice distortion. Applying pressure suppresses the insulating state, but enhances the magnetism as the superexchange increases with decreasing lattice constant. By comparing our results under pressure to previous studies of doped crystals, we show that this dependence of the magnetism on the lattice constant is consistent for both band broadening and band filling. In the high-pressure metallic phase the lattice symmetry is reduced from cubic to monoclinic, pointing to the primary influence of charge correlations at the transition. There exists a wide regime of phase separation that may be a general characteristic of correlated quantum matter.

Feng, Y.; Jaramillo, R.; Banerjee, A.; Honig, J. M.; Rosenbaum, T. F. (X-Ray Science Division); (Univ. of Chicago); (Harvard Univ.); (Purdue Univ.)

2011-01-01T23:59:59.000Z

424

Final LDRD report : metal oxide films, nanostructures, and heterostructures for solar hydrogen production.  

SciTech Connect (OSTI)

The distinction between electricity and fuel use in analyses of global power consumption statistics highlights the critical importance of establishing efficient synthesis techniques for solar fuels-those chemicals whose bond energies are obtained through conversion processes driven by solar energy. Photoelectrochemical (PEC) processes show potential for the production of solar fuels because of their demonstrated versatility in facilitating optoelectronic and chemical conversion processes. Tandem PEC-photovoltaic modular configurations for the generation of hydrogen from water and sunlight (solar water splitting) provide an opportunity to develop a low-cost and efficient energy conversion scheme. The critical component in devices of this type is the PEC photoelectrode, which must be optically absorptive, chemically stable, and possess the required electronic band alignment with the electrochemical scale for its charge carriers to have sufficient potential to drive the hydrogen and oxygen evolution reactions. After many decades of investigation, the primary technological obstacle remains the development of photoelectrode structures capable of efficient conversion of light with visible frequencies, which is abundant in the solar spectrum. Metal oxides represent one of the few material classes that can be made photoactive and remain stable to perform the required functions.

Kronawitter, Coleman X. [Lawrence Berkeley National Laboratory, Berkeley, CA; Antoun, Bonnie R.; Mao, Samuel S. [Lawrence Berkeley National Laboratory, Berkeley, CA

2012-01-01T23:59:59.000Z

425

Degradation of solid oxide fuel cell metallic interconnects in fuels containing sulfur  

SciTech Connect (OSTI)

Hydrogen is the main fuel for all types of fuel cells except direct methanol fuel cells. Hydrogen can be generated from all manner of fossil fuels, including coal, natural gas, diesel, gasoline, other hydrocarbons, and oxygenates (e.g., methanol, ethanol, butanol, etc.). Impurities in the fuel can cause significant performance problems and sulfur, in particular, can decrease the cell performance of fuel cells, including solid oxide fuel cells (SOFC). In the SOFC, the high (800-1000°C) operating temperature yields advantages (e.g., internal fuel reforming) and disadvantages (e.g., material selection and degradation problems). Significant progress in reducing the operating temperature of the SOFC from ~1000 ºC to ~750 ºC may allow less expensive metallic materials to be used for interconnects and as balance of plant (BOP) materials. This paper provides insight on the material performance of nickel, ferritic steels, and nickel-based alloys in fuels containing sulfur, primarily in the form of H2S, and seeks to quantify the extent of possible degradation due to sulfur in the gas stream.

Ziomek-Moroz, M.; Hawk, Jeffrey A.

2005-01-01T23:59:59.000Z

426

Synthesis of Metal Oxide Nanomaterials for Chemical Sensors by Molecular Beam Epitaxy  

SciTech Connect (OSTI)

Since the industrial revolution, detection and monitoring of toxic matter, chemical wastes, and air pollutants has become an important environmental issue. Thus, it leads to the development of chemical sensors for various environmental applications. The recent disastrous oil spills over the near-surface of ocean due to the offshore drilling emphasize the use of chemical sensors for prevention and monitoring of the processes that might lead to these mishaps.1, 2 Chemical sensors operated on a simple principle that the sensing platform undergoes a detectable change when exposed to the target substance to be sensed. Among all the types of chemical sensors, solid state gas sensors have attracted a great deal of attention due to their advantages such as high sensitivity, greater selectivity, portability, high stability and low cost.3, 4 Especially, semiconducting metal oxides such as SnO2, TiO2, and WO3 have been widely used as the active sensing platforms in solid state gas sensors.5 For the enhanced properties of solid state gas sensors, finding new sensing materials or development of existing materials will be needed. Thus, nanostructured materials such as nanotubes,6-8 nanowires,9-11 nanorods,12-15 nanobelts,16, 17 and nano-scale thin films18-23 have been synthesized and studied for chemical sensing applications.

Nandasiri, Manjula I.; Kuchibhatla, Satyanarayana V N T; Thevuthasan, Suntharampillai

2013-12-01T23:59:59.000Z

427

Growth of monodisperse mesoscopic metal-oxide colloids under constant monomer supply  

Science Journals Connector (OSTI)

In closed systems, control over the size of monodisperse metal-oxide colloids is generally limited to submicrometric dimensions. To overcome this difficulty, we explore the formation and growth of silica particles under constant monomer supply. The monomer source is externally driven by the progressive addition into the system of one of the precursors. Monodisperse spherical particles are produced up to a mesoscopic size. We analyze their growth versus the monomer addition rate at different temperatures. Our results show that in the presence of a continuous monomer addition, growth is limited by diffusion over the investigated temporal window. Using the temperature variation of the growth rate, we prove that rescaling leads to a data reduction onto a single master curve. Contrary to the growth process, the final particle’s size reached after the end of the reagent supply strongly depends on the addition rate. The variation of the final particle size versus addition rate can be deduced from an analogy with crystal formation in jet precipitation. Within this framework, and using the temperature dependences of both the particle growth law and the final size, we determine the value of the molecular heat of dissolution associated to the silica solubility. These observations support the fact that classical theories of phase-ordering dynamics can be extended to the synthesis of inorganic particles. The emergence of a master behavior in the presence of continuous monomer addition also suggests the extension of these theories to open systems.

Koh Nozawa; Marie-Hélène Delville; Hideharu Ushiki; Pascal Panizza; Jean-Pierre Delville

2005-07-11T23:59:59.000Z

428

Doped palladium containing oxidation catalysts  

DOE Patents [OSTI]

A supported oxidation catalyst includes a support having a metal oxide or metal salt, and mixed metal particles thereon. The mixed metal particles include first particles including a palladium compound, and second particles including a precious metal group (PMG) metal or PMG metal compound, wherein the PMG metal is not palladium. The oxidation catalyst may also be used as a gas sensor.

Mohajeri, Nahid

2014-02-18T23:59:59.000Z

429

Metallic Interconnects for Solid Oxide Fuel Cell: Performance of Reactive Element Oxide Coating During 10, 20 and 30 Months Exposure  

Science Journals Connector (OSTI)

One of challenges in improving the performance and cost-effectiveness of SOFCs (Solid Oxide Fuel Cells) is the development of suitable interconnect materials. Chromia-forming alloys and especially ferritic sta...

S. Fontana; S. Chevalier; G. Caboche

2012-12-01T23:59:59.000Z

430

Gas Phase Ion Chemistry of Transition Metal Clusters: Production, Reactivity, and Catalysis  

Science Journals Connector (OSTI)

This review focuses on the use of mass spectrometry to examine the gas phase ion chemistry of metal clusters. Ways of forming gas phase clusters are briefly overviewed and then the gas phase chemistry of silve...

Richard A. J. O'Hair; George N. Khairallah

2004-09-01T23:59:59.000Z

431

Scaling properties in the adsorption of ionic polymeric surfactants on generic nanoparticles of metallic oxides by mesoscopic simulation  

E-Print Network [OSTI]

We study the scaling of adsorption isotherms of polyacrylic dispersants on generic surfaces of metallic oxides $XnOm$ as a function of the number of monomeric units, using Electrostatic Dissipative Particle Dynamics simulations. The simulations show how the scaling properties in these systems emerge and how the isotherms rescale to a universal curve, reproducing reported experimental results. The critical exponent for these systems is also obtained, in perfect agreement with the scaling theory of deGennes. Some important applications are mentioned.

E. Mayoral; E. Nahmad-Achar

2014-02-11T23:59:59.000Z

432

Geochemical, metagenomic and metaproteomic insights into trace metal utilization by methane-oxidizing microbial consortia in sulfidic marine sediments  

SciTech Connect (OSTI)

Microbes have obligate requirements for trace metals in metalloenzymes that catalyze important biogeochemical reactions. In anoxic methane- and sulfide-rich environments, microbes may have unique adaptations for metal acquisition and utilization due to decreased bioavailability as a result of metal sulfide precipitation. However, micronutrient cycling is largely unexplored in cold ( 10 C) and sulfidic (>1 mM H2S) deep-sea methane seep ecosystems. We investigated trace metal geochemistry and microbial metal utilization in methane seeps offshore Oregon and California, USA, and report dissolved concentrations of nickel (0.5-270 nM), cobalt (0.5-6 nM), molybdenum (10-5,600 nM) and tungsten (0.3-8 nM) in Hydrate Ridge sediment porewaters. Despite low levels of cobalt and tungsten, metagenomic and metaproteomic data suggest that microbial consortia catalyzing anaerobic oxidation of methane utilize both scarce micronutrients in addition to nickel and molybdenum. Genetic machinery for cobalt-containing vitamin B12 biosynthesis was present in both anaerobic methanotrophic archaea (ANME) and sulfate-reducing bacteria (SRB). Proteins affiliated with the tungsten-containing form of formylmethanofuran dehydrogenase were expressed in ANME from two seep ecosystems, the first evidence for expression of a tungstoenzyme in psychrotolerant microorganisms. Finally, our data suggest that chemical speciation of metals in highly sulfidic porewaters may exert a stronger influence on microbial bioavailability than total concentration

Glass, DR. Jennifer [California Institute of Technology, Pasadena; Yu, DR. Hang [California Institute of Technology, Pasadena; Steele, Joshua [California Institute of Technology, Pasadena; Dawson, Katherine [California Institute of Technology, Pasadena; Sun, S [University of California, San Diego; Chourey, Karuna [ORNL; Hettich, Robert {Bob} L [ORNL; Orphan, V [California Institute of Technology, Pasadena

2014-01-01T23:59:59.000Z

433

Product/metal ratio (PMR): A novel criterion for the evaluation of electrolytes on micro-arc oxidation (MAO) of Mg and its alloys  

Science Journals Connector (OSTI)

Product/metal ratio (PMR...) was introduced as a novel criterion for the evaluation of electrolytes on micro-arc oxidation (MAO) of Mg and its alloys....PBR), focused on the roles of electrolytes for the compactn...

LaiWen Song; YingWei Song; DaYong Shan; GuoYi Zhu…

2011-10-01T23:59:59.000Z

434

Single crystal flow reactor for studying reactivities on metal oxide model catalysts at atmospheric pressure to bridge the pressure gap to the adsorption properties determined under UHV conditions  

Science Journals Connector (OSTI)

A flow reactor for the investigation of heterogeneous catalytic reactions on single crystalline metal oxide model catalysts has been designed. It is located in a high pressure cell attached to an UHV analysis cha...

C. Kuhrs; M. Swoboda; W. Weiss

2001-01-01T23:59:59.000Z

435

Investigation on edge fringing effect and oxide thickness dependence of inversion current in metal-oxide-semiconductor tunneling diodes with comb-shaped electrodes  

SciTech Connect (OSTI)

A particular edge-dependent inversion current behavior of metal-oxide-semiconductor (MOS) tunneling diodes was investigated utilizing square and comb-shaped electrodes. The inversion tunneling current exhibits the strong dependence on the tooth size of comb-shaped electrodes and oxide thickness. Detailed illustrations of current conduction mechanism are developed by simulation and experimental measurement results. It is found that the electron diffusion current and Schottky barrier height lowering for hole tunneling current both contribute on inversion current conduction. In MOS tunneling photodiode applications, the photoresponse can be improved by decreasing SiO{sub 2} thickness and using comb-shaped electrodes with smaller tooth spacing. Meantime, the high and steady photosensitivity can also be approached by introducing HfO{sub 2} into dielectric stacks.

Lin, Chien-Chih; Hsu, Pei-Lun; Lin, Li; Hwu, Jenn-Gwo, E-mail: jghwu@ntu.edu.tw [Graduate Institute of Electronics Engineering, Department of Electrical Engineering, National Taiwan University, Taipei 10617, Taiwan (China)

2014-03-28T23:59:59.000Z

436

E-Print Network 3.0 - award metal ion Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

-5 A number of recent experiments have sought to extend the realm of gas phase transition metal ion chemistry... to ex- amples where the ion occupies an oxidation state that...

437

High Activity of Ce1-xNixO2-y for H2 Production through Ethanol Steam Reforming: Tuning Catalytic Performance through Metal-Oxide Interactions  

SciTech Connect (OSTI)

The importance of the oxide: Ce{sub 0.8}Ni{sub 0.2}O{sub 2-y} is an excellent catalyst for ethanol steam reforming. Metal-oxide interactions perturb the electronic properties of the small particles of metallic nickel present in the catalyst under the reaction conditions and thus suppress any methanation activity. The nickel embedded in ceria induces the formation of O vacancies, which facilitate cleavage of the OH bonds in ethanol and water.

G Zhou; L Barrio; S Agnoli; S Senanayake; J Evans; A Kubacka; M Estrella; J Hanson; A Martinez-Arias; et al.

2011-12-31T23:59:59.000Z

438

Electronic structure of perovskite oxide surfaces at elevated temperatures and its correlation with oxygen reduction reactivity  

E-Print Network [OSTI]

The objective is to understand the origin of the local oxygen reduction reaction (ORR) activity on the basis of the local electronic structure at the surface of transition metal oxides at elevated temperatures and in oxygen ...

Chen, Yan, Ph. D. Massachusetts Institute of Technology

2014-01-01T23:59:59.000Z

439

Fabrication of Metal/Oxide Nanostructures by Anodization Processes for Biosensor, Drug Delivery and Supercapacitor Applications  

E-Print Network [OSTI]

applications of micro/nano structures; (2) novel processes to innovate anodic aluminum oxide nanotube template; (3) the supercapacitor applications of anodic titanium oxide. First, the extremely high surface area AAO coated microneedle and microneedle array...

Chen, Po-Chun

2014-01-13T23:59:59.000Z

440

Operation of mixed conducting metal oxide membrane systems under transient conditions  

DOE Patents [OSTI]

Method of operating an oxygen-permeable mixed conducting membrane having an oxidant feed side, an oxidant feed surface, a permeate side, and a permeate surface, which method comprises controlling the differential strain between the permeate surface and the oxidant feed surface at a value below a selected maximum value by varying the oxygen partial pressure on either or both of the oxidant feed side and the permeate side of the membrane.

Carolan, Michael Francis (Allentown, PA)

2008-12-23T23:59:59.000Z

Note: This page contains sample records for the topic "transition metal oxide" 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.


441

Gettering of transition metals by cavities in silicon formed by helium ion implantation  

SciTech Connect (OSTI)

We have recently completed studies which quantitatively characterize the ability of nanometer-size cavities formed by He ion implantation to getter detrimental metal impurities in Si. Cavity microstructures formed in Si by ion implantation of He and subsequent annealing have been found to capture metal impurities by two mechanisms: (1) chemisorption on internal walls at low concentrations and (2) silicide precipitation at concentrations exceeding the solid solubility. Experiments utilizing ion-beam analysis, cross-sectional transmission electron microscopy, and secondary ion mass spectrometry were performed to quantitatively characterize the gettering effects and to determine the free energies associated with the chemisorbed metal atoms as a function of temperature. Mathematical models utilizing these results have been developed to predict gettering behavior.

Petersen, G.A.; Myers, S.M.; Follstaedt, D.M.

1996-09-01T23:59:59.000Z

442

Modeling Ethanol Decomposition on Transition Metals: A Combined Application of Scaling and Brønsted-Evans-Polanyi Relations  

SciTech Connect (OSTI)

Applying density functional theory (DFT) calculations to the rational design of catalysts for complex reaction networks has been an ongoing challenge, primarily because of the high computational cost of these calculations. Certain correlations can be used to reduce the number and complexity of DFT calculations necessary to describe trends in activity and selectivity across metal and alloy surfaces, thus extending the reach of DFT to more complex systems. In this work, the well-known family of Brønsted-Evans-Polanyi (BEP) correlations, connecting minima with maxima in the potential energy surface of elementary steps, in tandem with a scaling relation, connecting binding energies of complex adsorbates with those of simpler ones (e.g., C, O), is used to develop a potential-energy surface for ethanol decomposition on 10 transition metal surfaces. Using a simple kinetic model, the selectivity and activity on a subset of these surfaces are calculated. Experiments on supported catalysts verify that this simple model is reasonably accurate in describing reactivity trends across metals, suggesting that the combination of BEP and scaling relations may substantially reduce the cost of DFT calculations required for identifying reactivity descriptors of more complex reactions.

Ferrin, Peter A.; Simonetti, Dante A.; Kandoi, Shampa; Kunkes, Edward L.; Dumesic, James A.; Norskov, Jens K.; Mavrikakis, Manos

2009-04-29T23:59:59.000Z

443

Anomalous magnetic behavior in the transition metal ions doped Cu{sub 2}O flower-like nanostructures  

SciTech Connect (OSTI)

Cuprous oxide (Cu{sub 2}O) flower-like nanostructures doped with various metal ions i.e. Fe, Co, Ni and Mn have been synthesized by an organic phase solution method. The powder X-ray diffraction study clearly reveals them as single phase simple cubic cuprite lattice. Study of their magnetic properties have shown that these doped samples are ferromagnetic in nature; however, no such property was observed for the undoped Cu{sub 2}O sample. The magnitude of the ferromagnetic behavior was found to be dependent on the dopant metal ions amount, which increased consistently with its increase. As total magnetic moment contribution of the doped metal ions calculated was insignificant, it is believed to have originated from the induced magnetic moments at cation deficiency sites in the material, created possibly due to the disturbance of the crystal lattice by the dopant ions. The existence of the defects has been supported by photoluminescence spectra of the doped samples. -- Graphical abstract: Room temperature ferromagnetic behavior was observed in the Cu{sub 2}O nanoflowers doped with Fe, Co, Ni and Mn ions. Cation deficiencies formed due to dopant ions were possibly responsible for ferromagnetism. Display Omitted

Ahmed, Asar [Department of Chemistry, Indian Institute of Technology Kanpur, Uttar Pradesh (India); Gajbhiye, Namdeo S., E-mail: nsg@iitk.ac.i [Department of Chemistry, Indian Institute of Technology Kanpur, Uttar Pradesh (India)

2011-01-15T23:59:59.000Z

444

The transformation of organic amines by transition metal cluster compounds. Progress report, 1993--1994  

SciTech Connect (OSTI)

In the recent year, the authors extended investigations into insertion reactions by investigating the insertion of dicarboxylate acetylene into the metal-metal bond of Re{sub 2}(CO){sub 9}(NCMe). Secondly, the authors considered the ring opening reactions of the cyclic thioethers: tetrahydrothiophene and thiacyclohexane when complexed to Os{sub 3}(CO){sub 10}(NCMe){sub 2}. In a third effort, various osmium complexes of cyclobutynes were synthesized and the subsequent reactivity probed. Finally, energy storage (via absorption of UV-visible photons) in osmium cluster compounds was investigated.

Adams, R.D.

1994-01-01T23:59:59.000Z

445

E-Print Network 3.0 - alkali metal oxides Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

, sodium carbide, turpentine, finely divided metals Calcium water, carbon dioxide, carbon tetrachloride... , and chlorinated hydrocarbons Carbon, activated calcium...

446

Low Temperature Deposition of Metal Oxide Thin Films in Supercritical Carbon Dioxide using Metal-organic Precursors  

E-Print Network [OSTI]

and are driven by the energy provided by a heated substrate. Both these vacuum-based techniques require in the precursor adsorption, oxidation and by-product desorption. [5] Use of solvation energy may provide a viable. Pressurized CO2 was delivered using an ISCO 260D syringe pump through a high- pressure manifold. Resistive

Gougousi, Theodosia

447

Hydrolysis of Naptalam and Structurally Related Amides: Inhibition by Dissolved Metal Ions and Metal (Hydr)Oxide Surfaces  

E-Print Network [OSTI]

. INTRODUCTION Several important classes of agrochemicals possess amide and anilide functional groups. Naptalam). Agrochemicals often possess functional groups in the vicinity of amide and anilide linkages; participation and anilide agrochemicals. Granados et al. (1995) reported no significant effects of dissolved divalent metal

Huang, Ching-Hua

448

Axially Engineered Metal-Insulator Phase Transition by Graded Doping VO2 Nanowires  

E-Print Network [OSTI]

transition yields an extremely high temperature coefficient of resistivity 10%/K, simultaneously with a very low resistivity down to 0.001 ·cm, making these NWs promising infrared sensing materials for uncooled microbolometers. Lastly, they form bimorph thermal actuators that bend with an unusually high curvature, 900 m-1

Wu, Junqiao

449

Physica B 398 (2007) 407411 Metal-insulator transition in correlated systems  

E-Print Network [OSTI]

, CNEA, (8400) San Carlos de Bariloche, Argentina c Laboratoire de Physique des Solides, CNRS-UMR8502, Ciudad Universitaria, Pabello´n 1, Buenos Aires (1428), Argentina Abstract We study the Mott transition correlated systems in which the competition between the kinetic and Coulomb energy of electrons, which

Miranda, Eduardo

450

Copolymerization Studies of Vinyl Chloride and Vinyl Acetate with Ethylene Using a Transition-Metal Catalyst  

E-Print Network [OSTI]

monomers with polar functionality (such as vinyl acetate (VA), vinyl chloride (VC), and acrylates).1 OverCopolymerization Studies of Vinyl Chloride and Vinyl Acetate with Ethylene Using a Transition-Flory constants were identical (0.81) for the ethylene homopolymerizations and the ethylene/vinyl chloride

Goddard III, William A.

451

Stereochemistryof Reactionsat Carbon-Transition Metal o Bonds. (CH,),CCHDCHDFe(CO),C,H^'  

E-Print Network [OSTI]

involvesintermediatefree carbon radicalsor ions or occurs by SN2 or Sn2 transition states. It is experimentally difficult,3-dimethylbutan-l-ol-1,2-dz(1) are de- scribed. Reaction of the p-bromobenzenesulfonateestersof 1 with C,4-dimethylpentanoic-2,3-d2acid with >90% retention of configuration at carbon. Reaction of 2 with sulfur dioxide

Prentiss, Mara

452

Computational Studies of the Electronic Structures and Mechanisms of Late Transition Metal Systems  

E-Print Network [OSTI]

that were studied. The first system focuses on the formation of a carbon-bromine bond from the reaction of Ni(Ar)(Br)(pic) (Ar = 2-phenylpyridine, pic = 2-picoloine) with Br2. Unlike the typical behavior of heavier group 10 metals that have a wider range...

Pitts, Amanda

2013-08-27T23:59:59.000Z

453

Transition metal chemistry of 1,3-diynes, poly-ynes, and related compounds  

Science Journals Connector (OSTI)

Publisher Summary This chapter discusses the complexes with ?-bonded diynyl and poly-ynyl ligands, together with a description of their reaction chemistry and routine spectroscopic properties, followed by a description of the various ?2-bonded systems featuring one or more metal centers. Introduction of two or more terminal diyne units, either at a metal center or, for example, on a ?-ring complex, leads to the possibility of generating metal-containing polymers. Experimental and theoretical work leading to a description of the MC- and CC-bonding interactions in di- and poly-ynyl systems is presented in the chapter. Numerous reactions of diynes and poly-ynes with metal species that lead to products distinct from those previously discussed are described in, as are C–C bond forming reactions that lead to poly-ynes. Other ligands containing diynyl groups are discussed in the chapter. The preparative chemistry and electronic structures (where possible) of metalladiynes are discussed, and a survey of novel materials obtained from diyne complexes are reviewed.

Paul J. Low; Michael I. Bruce

2001-01-01T23:59:59.000Z

454

Synthesis of Mixed Metal Oxides for Hydrodeoxygenation of Pyrolysis Oil for Alternative Fuels Sarah McNew, Tiorra Ross and Carsten Sievers  

E-Print Network [OSTI]

· Flash pyrolysis on biomass [1] · Short residence times and flexible feed · Bio-oils produced are close to dissociate hydrogen Goal: synthesize metal free, sulfur free, catalysts for HDO Biomass Pyrolysis OilSynthesis of Mixed Metal Oxides for Hydrodeoxygenation of Pyrolysis Oil for Alternative Fuels Sarah

Das, Suman

455

Cu–Zn–Al mixed metal oxides derived from hydroxycarbonate precursors for H2S removal at low temperature  

Science Journals Connector (OSTI)

One series of Cu–Zn and two series of Cu–Zn–Al hydroxycarbonate precursors with varying metal molar ratios were prepared via co-precipitation or multi-precipitation method, and the mixed metal oxides obtained by calcination of the precursor materials were used as adsorbents for H2S removal in the range of 25–100 °C. The results of H2S adsorption tests showed that these mixed oxides, especially two series of Cu–Zn–Al mixed metal oxides exhibited markedly high breakthrough sulfur capacities (ranging from 4.4 to 25.7 g S/100 g-sorbent with increase of Cu/Zn molar ratio) at 40 °C. Incorporation Cu and/or Al decreased the mean crystalline sizes of ZnO and CuO species in the Cu–Zn and Cu–Zn–Al mixed metal oxide adsorbents by decreasing of mean crystalline sizes of hydroxycarbanate phases mainly including hydrozincite, aurichalcite and malachite, segregation of Al phase, etc. Higher breakthrough sulfur capacity of each adsorbent in two ternary series than that of the corresponding adsorbent in binary series should be ascribed to the enhancement of the dispersion of ZnO and/or CuO species with incorporation of aluminum, thereby increasing the overall rate of reaction between the adsorbent and H2S by reducing the thickness of potential sulfide shell on the outer layer of the oxide crystalline grains and increasing the area of the interface for the exchange of HS?/S2? and O2?. For each series of adsorbents, the breakthrough sulfur capacity increased with the increase of Cu/Zn molar ratio regardless of changes of the dispersion of CuO and/or ZnO. This phenomenon might be mainly attributed to faster rate of the lattice diffusion of HS?, S2? and O2? or exchange of HS?/S2? and O2? during the sulfidation of CuO than that during the sulfidation of ZnO due to less rearrangement of the anion lattice.

Dahao Jiang; Lianghu Su; Lei Ma; Nan Yao; Xiaoliang Xu; Haodong Tang; Xiaonian Li

2010-01-01T23:59:59.000Z

456

Ab initio calculations of the physical properties of transition metal carbides and nitrides and possible routes to high-T{sub c} superconductivity  

SciTech Connect (OSTI)

We report ab initio linear-response calculations of the phonon spectra and the electron-phonon interaction for several transition metal carbides and nitrides in a NaCl-type structure. For NbC, the kinetic, optical, and superconducting properties are calculated in detail at various pressures and the normal-pressure results are found to agree well with the experiment. Factors accounting for the relatively low critical temperatures T{sub c} in transition metal compounds with light elements are considered and the possible ways of increasing T{sub c} are discussed.

Maksimov, E. G., E-mail: maksimov@lpi.ru; Ebert, S. V. [Lebedev Physics Institute (Russian Federation); Magnitskaya, M. V.; Karakozov, A. E. [Vereshchagin Institute for High Pressure Physics (Russian Federation)

2007-10-15T23:59:59.000Z

457

Electronic Structure of Transition Metal Clusters and Actinide Complexes and Their Reactivity  

SciTech Connect (OSTI)

Our research in this area since October 2007 has resulted in seven completed publications and more papers of the completed work are in progress. Our work during this period principally focused on actinide complexes with secondary emphasis on spectroscopic properties and electronic structure of metal complexes. As the publications are available online with all of the details of the results, tables and figures, we are providing here only a brief summary of major highlights, in each of the categories.

Balasubramanian, K

2008-10-06T23:59:59.000Z

458

J. Am. Chem. SOC.1993, 115, 2357-2362 2357 Metal-Metal Bonding in Engel-Brewer Intermetallics  

E-Print Network [OSTI]

. Introduction Materials that exhibit high thermal stability and resistance to oxidation and corrosion of transition metals might possibly serve as both highly stable catalysts and as thermally stable, oxidation-resistant to be extremely thermally stable in the bulk form. We find the atomization energy of the ZrPt, cluster at its bulk

Carter, Emily A.

459

The transformation of organic amines by transition metal cluster compounds: Progress report  

SciTech Connect (OSTI)

Research during the current award period has covered several related topics which have emerged and grown as a consequence of the various discoveries that have been made during this award period. They have been divided into the following subsections for clarity and emphasis: The activation of tertiary amines by osmium cluster complexes; CH bond activation and ring opening of a nitrogen containing strained ring heterocycle by an osmium cluster complex; Ring opening of cyclic thioethers; cyclooligomerization of Thietanes; Studies of the cyclobutyne ligand; Insertion of an alkynes into metal-metal bonds; and Energy storage in metal clusters. A summary of the results of these studies is given in the following sections of this report. These studies have resulted in 50 scientific publications over the last three years and details of their studies beyond that given in the following sections can be found in those reports. All of these reports are listed in the final section of this report by the author`s names, title and journal citation.

Adams, R.D.

1994-11-01T23:59:59.000Z

460

Crystalline to amorphous phase transition of tin oxide nanocrystals induced by SHI at low temperature  

SciTech Connect (OSTI)

Tin oxide (SnO{sub 2}) thin films were deposited using pulsed laser deposition (PLD) technique on Si substrates. The as-deposited films were irradiated using 100 MeV Ag ions at different fluences ranging from 3x10{sup 13} to 3x10{sup 14} ions/cm{sup 2} at an incidence angle of 75 deg. with respect to surface normal at liquid nitrogen (LN2) temperature. The as-deposited and irradiated films have been characterized using X-ray diffraction (XRD) and atomic force microscopy (AFM) techniques to study the modifications in structural and surface morphological properties. Nanocrystalline film become completely amorphous and nanograins of tin oxide disappeared from the surface as indicated by XRD spectra and AFM micrographs respectively.

Kumar, Vijay; Pratap, Deepti; Jain, Anshul; Agarwal, D. C.; Sulania, I.; Tripathi, A.; Chaudhary, R. J.; Chauhan, R. S. [Department of Physics, R.B.S. College, Agra, U.P.,-282 002 (India); Inter-University Accelerator Centre, New Delhi, -110 067 (India); UGC-DAE CSR, Khandwa Road, Indore, M.P., -452 017 (India); Department of Physics, R.B.S. College, Agra, U.P., -282 002 (India)

2012-06-05T23:59:59.000Z

Note: This page contains sample records for the topic "transition metal oxide" from the National Library of EnergyBeta (NLEBeta).
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461

Control of differential strain during heating and cooling of mixed conducting metal oxide membranes  

DOE Patents [OSTI]

Method of operating an oxygen-permeable mixed conducting membrane having an oxidant feed side and a permeate side, which method comprises controlling the differential strain between the oxidant feed side and the permeate side by varying either or both of the oxygen partial pressure and the total gas pressure on either or both of the oxidant feed side and the permeate side of the membrane while changing the temperature of the membrane from a first temperature to a second temperature.

Carolan, Michael Francis (Allentown, PA)

2007-12-25T23:59:59.000Z

462

Model of thermally activated magnetization reversal in thin films of amorphous rare-earth-transition-metal alloys  

Science Journals Connector (OSTI)

Monte Carlo simulations on a two-dimensional lattice of magnetic dipoles have been performed to investigate the magnetic reversal by thermal activation in rare-earth-transition-metal (RE-TM) alloys. Three mechanisms of magnetization reversal were observed: nucleation dominated growth, nucleation followed by the growth of magnetic domains containing no seeds of unreversed magnetization, and nucleation followed by dendritic domain growth by successive branching in the motion of the domain walls. The domain structures are not fractal; however, the fractal dimension of the domain wall was found to be a good measure of the jaggedness of the domain boundary surface during the growth process. The effects of the demagnetizing field on the hysteretic and time-dependent properties of the thin films were studied and some limitations in the application of the Fatuzzo model on magneto-optic media are identified.

A. Lyberatos; J. Earl; R. W. Chantrell

1996-03-01T23:59:59.000Z

463

Transition-metal (Au, Pt, Ir, Re) bonding to Al,Si,Ge: X-ray-absorption studies  

Science Journals Connector (OSTI)

We report transition-metal (T) L2 and L3 near-edge x-ray-absorption spectroscopy measurements on more than a score of T-X compounds with T=Au, Pt, Ir, and Re and X=Al, Si, and Ge. We correlate the strength of the (2p?5d)-related ‘‘white line’’ feature at these edges to the degree of chemical-bonding-induced 5d-orbital charge transfer in these materials. Similar bonding trends are shown to be present in 1:2:2 compounds involving these T and X elements. Finally, the bonding-induced charge-transfer effects in such T-X compounds are discussed along with the Pauling electronegativity scale. [L. Pauling, The Nature of the Chemical Bond (Cornell University Press, New York, 1960), p. 93.

Y. Jeon, Boyun Qi, F. Lu, and M. Croft

1989-07-15T23:59:59.000Z

464

Electron Core-Hole Interaction in the X-Ray Absorption Spectroscopy of 3d Transition Metals  

Science Journals Connector (OSTI)

A fully relativistic scheme is presented that allows one to deal with the electronic band structure of a solid and the influence of the electron core-hole interaction on its x-ray absorption spectra on the same level. This is achieved in a parameter-free way by working throughout in the framework of the time-dependent density functional theory and linear response formalism. Application to the L2,3-absorption spectra of 3d transition metals demonstrates that the electron core-hole interaction intermixes the L2 and L3 partial spectra, strongly affecting the so-called branching ratio. The consequences of this for the magnetic circular x-ray dichroism sum rules are discussed.

J. Schwitalla and H. Ebert

1998-05-18T23:59:59.000Z

465

Divacancy-nitrogen-assisted transition metal dispersion and hydrogen adsorption in defective graphene: A first-principles study  

Science Journals Connector (OSTI)

We propose a route to dispersing hydrogen-adsorbing transition metals (TMs) on a large scale onto vacancy-engineered defective graphenes by employing natural carbon-nitrogen-TM complexes, i.e., TM-containing porphyrins. Based on first-principles density-functional calculations, the TM-porphyrin core—made of one central TM and four surrounding nitrogen atoms—can be effectively generated by three defect-engineering processes of graphenes: (1) creation of carbon divacancies, (2) nitrogen substitution of unsaturated carbons, and (3) TM incorporation. The atomistically dispersed Sc, Ti, and V are able to adsorb hydrogen molecules as strongly as 0.2–0.4 eV with the Kubas coordination. The Fe-porphyrin-like unit in graphenes can also have the Kubas adsorption of hydrogen, if the exchange splitting is reduced by a compressive in-plane strain.

Woon Ih Choi; Seung-Hoon Jhi; Kwiseon Kim; Yong-Hyun Kim

2010-02-25T23:59:59.000Z

466

Molten Metal Anodes for Direct Carbon-Solid Oxide Fuel Cells.  

E-Print Network [OSTI]

??The aim of this thesis was to enable the direct utilization of solid carbonaceous fuels like coal and biomass, in solid oxide fuel cells (SOFC).… (more)

Jayakumar, Abhimanyu

2012-01-01T23:59:59.000Z

467

First-Order Transition from Superfluid to Bose-Metal State in Systems with Resonant Pairing  

Science Journals Connector (OSTI)

Systems showing resonant superfluidity, driven by an exchange coupling of strength g between uncorrelated pairs of itinerant fermions and tightly bound ones, undergo a first-order phase transition as g increases beyond some critical value gc. The superfluid phase for g?gc is characterized by a gap in the fermionic single-particle spectrum and an acoustic sound-wave-like collective mode of the bosonic resonating fermion pairs inside this gap. For g>gc this state gives way to a phase-uncorrelated bosonic liquid with a q2 spectrum.

T. Stauber and J. Ranninger

2007-07-26T23:59:59.000Z

468

Superconducting Transition-Temperature and Other Properties of Thin Metallic-Films  

E-Print Network [OSTI]

March 1975) We point out that the results of (1) Shapoval, for the superconducting transition temperature of a thin film, (2) Nedorezov, for the surface contributions to the density of states, Fermi energy, and specific heat, and (3) Cooper and Hu...) the value of (( 4(r) [ ) increases inside the film, away from the surface, and (b) the Fermi energy also increases. [Here (~4(r)(~) is an average of the square of the electronic wave function. ] These are the two effects which, in conjunction, according...

Allen, Roland E.

1975-01-01T23:59:59.000Z

469

Strain controlled systematic variation of metal-insulator transition in epitaxial NdNiO{sub 3} thin films  

SciTech Connect (OSTI)

We report here the strain dependent structural and electrical transport properties of epitaxial NdNiO{sub 3} thin films. Pulsed laser deposition technique was used to grow the NdNiO{sub 3} thin films on c-axis oriented SrTiO{sub 3} single crystals. Deposited films were irradiated using 200 MeV Ag{sup 15+} ion beam at the varying fluence (1 Multiplication-Sign 10{sup 11}, 5 Multiplication-Sign 10{sup 11}, and 1 Multiplication-Sign 10{sup 12} ions/cm{sup 2}). X-ray diffraction studies confirm the epitaxial growth of the deposited films, which is maintained even up to the highest fluence. Rise in the in-plane compressive strain has been observed after the irradiation. All the films exhibit metal-insulator transition, however, a systematic decrease in the transition temperature (T{sub MI}) has been observed after irradiation, which may be attributed to the increase in the in-plane compression. Raman spectroscopy data reveal that this reduction in T{sub MI}, with the irradiation, is related to the decrease in band gap due to the stress generated by the in-plane compressive strain.

Kumar, Yogesh [Materials Science Division, Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110 067 (India); Choudhary, R. J. [UGC-DAE Consortium for Scientific Research, Indore 452 001 (India); Kumar, Ravi [Materials Science Division, Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110 067 (India); Centre for Material Science and Engineering, National Institute of Technology, Hamirpur 177 005 (India)

2012-10-01T23:59:59.000Z

470

Thermal ionization induced metal-semiconductor transition and room temperature ferromagnetism in trivalent doped ZnO codoped with lithium  

SciTech Connect (OSTI)

Thermal ionization induced metallic to semiconductor (MST) transition occurring at 460?K for Zn{sub 0.97}Al{sub 0.03}O, 463?K for Zn{sub 0.94}Al{sub 0.03}Li{sub 0.03}O, and 503?K for Zn{sub 0.91}Al{sub 0.03}Li{sub 0.03}Mn{sub 0.03}O has been found in the sol-gel synthesized (using hexamethylenetetramine), trivalent doped (Al, Mn) ZnO codoped with lithium. Increase in the thermally ionized carrier concentration due to Al doping is responsible for near band edge (NBE) peak shift causing Fermi level to move into conduction band making it metallic consistent with resistivity results. Free carrier (thermally activated) neutralization with ionized donor is responsible for semiconducting nature, which is supported from the free carrier screening produced energy shift in the NBE of photoluminescence peak. Furthermore, independently band gap shrinkage is also obtained from UV-Visible studies confirming localization induced MST. An anti-correlation is found between defect density (DLE) and room temperature ferromagnetism (RTFM) indicating intrinsic defects are not directly responsible for RTFM.

Sivagamasundari, A.; Chandrasekar, S.; Pugaze, R.; Kannan, R., E-mail: kannan@pec.edu [Department of Physics, Pondicherry Engineering College, Puducherry 605 014 (India); Rajagopan, S. [Department of Chemistry, Pondicherry Engineering College, Puducherry 605 014 (India)

2014-03-07T23:59:59.000Z

471

Transition Metal Decorated Graphyne: An Efficient Catalyst for Oxygen Reduction Reaction  

Science Journals Connector (OSTI)

(63, 64) In the case of TM-N4 catalysts also, often the TMs are found to be ferromagnetic in nature and are shown to catalyze ORR. ... The prohibitive cost and scarcity of the noble-metal catalysts needed for catalyzing the O redn. ... Polarization graphs for the ORR reaction in PEMFC with Pt/(f-G-f-MWNT) as an electrocatalyst resulted in the best performance of 540 mW/cm2 for the Pt/(50% f-G+50% f-MWNT) cathode catalyst, agreeing with the electrochem. ...

K. Srinivasu; Swapan K. Ghosh

2013-11-20T23:59:59.000Z

472

Formation of amorphous superconducting transition-metal alloys by liquid quenching on hot substrates  

SciTech Connect (OSTI)

An improved cooling rate has been achieved by liquid quenching on a hot substrate, which facilitates the preparation of amorphous and metastable crystalline states of refractory-metal-based alloys. The effectiveness has been proved by the experimental results for Mo-Zr and Nb-Si-Ge alloys. A single amorphous phase was obtained from 40--60 at. % Zr. In the Nb-Si-Ge alloy system, amorphous and metastable A15 phases were obtained in a wide composition range. The superconducting properties and thermal stability of these phases have been studied.

Togano, K.; Kumakura, H.; Tachikawa, K.

1982-01-01T23:59:59.000Z

473

Experimental Study of Electron Transport through Nanometer-Scale Metal-Oxide Junctions  

E-Print Network [OSTI]

-annealing. The resistive bistability effect has been observed for all these materials, wi