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


1

Metallic Ferroelectricity and Superconductivity in the Transition Metal Oxide Pyrochlore Cd2Re2O7.  

E-Print Network (OSTI)

??Single crystalline samples of transition metal oxide Cd2Re2O7, the first superconductor among pyrochlore oxides with general formula A2B2O7 and the first example of “ferroelectric metal”… (more)

He, Jian

2004-01-01T23:59:59.000Z

2

High-Pressure Thermodynamic Properties of f-electron Metals, Transition Metal Oxides, and Half-Metallic Magnets  

SciTech Connect

This project involves research into the thermodynamic properties of f-electron metals, transition metal oxides, and half-metallic magnets at high pressure. These materials are ones in which the changing importance of electron-electron interactions as the distance between atoms is varied can tune the system through phase transitions from localized to delocalized electrons, from screened to unscreened magnetic moments, and from normal metal to one in which only a single spin specie can conduct. Three main thrusts are being pursued: (1) Mott transitions in transition metal oxides, (2) magnetism in half-metallic compounds, and (3) large volume-collapse transitions in f-band metals.

Scalettar, Richard T.; Pickett, Warren E.

2004-07-01T23:59:59.000Z

3

High-Pressure Thermodynamic Properties of f-electron Metals, Transition Metal Oxides, and Half-Metallic Magnets  

SciTech Connect

This project involves research into the thermodynamic properties of f-electron metals, transition metal oxides, and half-metallic magnets at high pressure. These materials are ones in which the changing importance of electron-electron interactions as the distance between atoms is varied can tune the system through phase transitions from localized to delocalized electrons, from screened to unscreened magnetic moments, and from normal metal to one in which only a single spin specie can conduct. Three main thrusts are being pursued: (i) Mott transitions in transition metal oxides, (ii) magnetism in half-metallic compounds, and (iii) large volume-collapse transitions in f-band metals.

Richard T. Scalettar; Warren E. Pickett

2005-08-02T23:59:59.000Z

4

Catalytic effects of period iv transition metal in the oxidation of biodiesel.  

E-Print Network (OSTI)

??CATALYTIC EFFECTS OF PERIOD IV TRANSITION METALS IN THE OXIDATION OF BIODIESEL BRADLEY R CLARK December 2011 Advisors: Dr. Steve Salley, Dr. Simon Ng, Dr.… (more)

Clark, Bradley

2012-01-01T23:59:59.000Z

5

Electrochemical lithiation and delithiation for control of magnetic properties of nanoscale transition metal oxides  

E-Print Network (OSTI)

Transition metal oxides comprise a fascinating class of materials displaying a variety of magnetic and electronic properties, ranging from half-metallic ferromagnets like CrO2, ferrimagnetic semiconductors like Fey's, and ...

Sivakumar, Vikram

2008-01-01T23:59:59.000Z

6

Functional transport properties in complex transition metal oxides  

Science Conference Proceedings (OSTI)

Transition oxide materials have a long and high-flying history due to their attractive properties. They are well-known today for magnets, high temperature superconductors as well as promising electronic materials. For example, BaTiO 3 ...

Hee Taek Yi / Sang-Wook Cheong

2010-01-01T23:59:59.000Z

7

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

DOE Green Energy (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

8

On the behavior of Bronsted-Evans-Polanyi Relations for Transition Metal Oxides  

SciTech Connect

Versatile Broensted-Evans-Polanyi (BEP) relations are found from density functional theory for a wide range of transition metal oxides including rutiles and perovskites. For oxides, the relation depends on the type of oxide, the active site and the dissociating molecule. The slope of the BEP relation is strongly coupled to the adsorbate geometry in the transition state. If it is final state-like the dissociative chemisorption energy can be considered as a descriptor for the dissociation. If it is initial state-like, on the other hand, the dissociative chemisorption energy is not suitable as descriptor for the dissociation. Dissociation of molecules with strong intramolecular bonds belong to the former and molecules with weak intramolecular bonds to the latter group. We show, for the prototype system La-perovskites, that there is a 'cyclic' behavior in the transition state characteristics upon change of the active transition metal of the oxide.

Vojvodic, Aleksandra

2011-08-22T23:59:59.000Z

9

O-vacancies in transition metal (TM) oxides: Coordination and local site symmetry of transition and negative ion states in TM2O3 and TMO2 oxides  

Science Conference Proceedings (OSTI)

Removal of neutral O-atoms from a transition metal (TM) oxide results in two electrons residing within the vacated site. Two-electron multiplet theory has been used to develop a d^2equivalent model. When applied to tetragonal HfO"2, the two electrons ... Keywords: Negative ion states, O-vacancy, Second derivative O K pre-edge spectra, Tanabe-Sugano diagrams, Transition metal oxides: X-ray absorption spectroscopy

G. Lucovsky; D. Zeller; J. L. Whitten

2011-07-01T23:59:59.000Z

10

Structure formation upon reactive direct current magnetron sputtering of transition metal oxide films  

Science Conference Proceedings (OSTI)

A comparative study of reactive direct current magnetron sputtering for different transition metal oxides reveals crystalline films at room temperature for group 4 and amorphous films for groups 5 and 6. This observation cannot be explained by the known growth laws and is attributed to the impact of energetic particles, originating from the oxidized target, on the growing film. This scenario is supported by measured target characteristics, the evolution of deposition stress of the films, and the observed backsputtering.

Ngaruiya, J.M.; Kappertz, O.; Mohamed, S.H.; Wuttig, M. [I. Physikalisches Institut der RWTH Aachen, D-52056 Aachen, Germany and Jomo Kenyatta University of Agriculture and Technology, Box 62000 Nairobi (Kenya); I. Physikalisches Institut der RWTH Aachen, D-52056 Aachen (Germany)

2004-08-02T23:59:59.000Z

11

The optical properties of magnesium oxide containing transition metal ions and defects produced by fast neutron irradiation  

Science Conference Proceedings (OSTI)

The photoluminescence (PL), its excitation (PLE) and optical absorption of MgO crystals containing transition metal ions and defects produced by fast neutron irradiation fluence up to 1020cm-2 (E>0.1 MeV) are investigated. Three ... Keywords: absorption, luminescence spectra, magnesium oxide, radiation defect, transition metal ions

Vera Skvortsova; Laima Trinkler

2010-11-01T23:59:59.000Z

12

Metal Oxidation Kinetics and the Transition from Thin to Thick Films  

SciTech Connect

We report an investigation of growth kinetics and transition from thin to thick films during metal oxidation. In the thin film limit (< 20 nm), Cabrera and Mott’s theory is usually adopted by explicitly considering ionic drift through the oxide in response to electric fields, where the growth kinetics follow an inverse logarithmic law . It is generally accepted that Wagner’s theory, involving self-diffusion, is valid only in the limit of thick film regime (>1?m) and leads to parabolic growth kinetics , where l is the oxide film thickness. Theory presented here unifies the two models and provides a complete description of oxidation including the transition from thin to thick film. The range of validity of Cabrera and Mott’s theory and Wagner’s theory can be well defined in terms of the Debye-Hückel screening length. The transition from drift-dominated ionic transport for thin film to diffusion-dominated transport for thick film is found to strictly follow the direct logarithmic law that is frequently observed in many experiments.

Xu, Zhijie; Rosso, Kevin M.; Bruemmer, Stephen M.

2012-09-01T23:59:59.000Z

13

Synthesis of transition metal nitride by nitridation of metastable oxide precursor  

SciTech Connect

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

14

Superconductors and Complex Transition Metal Oxides for Tunable THz Plasmonic Metamaterials  

Science Conference Proceedings (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

15

Hydrocracking and hydroisomerization of long-chain alkanes and polyolefins over metal-promoted anion-modified transition metal oxides  

DOE Patents (OSTI)

A method of cracking a feedstock by contacting the feedstock with a metal-promoted anion-modified metal oxide catalyst in the presence of hydrogen gas. The metal oxide of the catalyst is one or more of ZrO.sub.2, HfO.sub.2, TiO.sub.2 and SnO.sub.2, and the feedstock is principally chains of at least 20 carbon atoms. The metal-promoted anion-modified metal oxide catalyst contains one or more of Pt, Ni, Pd, Rh, Ir, Ru, (Mn & Fe) or mixtures of them present between about 0.2% to about 15% by weight of the catalyst. The metal-promoted anion-modified metal oxide catalyst contains one or more of SO.sub.4, WO.sub.3, or mixtures of them present between about 0.5% to about 20% by weight of the catalyst.

Venkatesh, Koppampatti R. (Pittsburgh, PA); Hu, Jianli (Cranbury, NJ); Tierney, John W. (Pittsburgh, PA); Wender, Irving (Pittsburgh, PA)

2001-01-01T23:59:59.000Z

16

Hydrocracking and hydroisomerization of long-chain alkanes and polyolefins over metal-promoted anion-modified transition metal oxides  

DOE Patents (OSTI)

A method is described for cracking a feedstock by contacting the feedstock with a metal-promoted anion-modified metal oxide catalyst in the presence of hydrogen gas. The metal oxide of the catalyst is one or more of ZrO{sub 2}, HfO{sub 2}, TiO{sub 2} and SnO{sub 2}, and the feedstock is principally chains of at least 20 carbon atoms. The metal-promoted anion-modified metal oxide catalyst contains one or more of Pt, Ni, Pd, Rh, Ir, Ru, (Mn and Fe) or mixtures of them present between about 0.2% to about 15% by weight of the catalyst. The metal-promoted anion-modified metal oxide catalyst contains one or more of SO{sub 4}, WO{sub 3}, or mixtures of them present between about 0.5% to about 20% by weight of the catalyst.

Venkatesh, Koppampatti R.; Hu, Jianli; Tierney, John W.; Wender, Irving

1996-12-01T23:59:59.000Z

17

Transition metal sulfide loaded catalyst  

DOE Patents (OSTI)

A zeolite-based catalyst is described for activation and conversion of methane. A zeolite support includes a transition metal (Mo, Cr or W) sulfide disposed within the micropores of the zeolite. The catalyst allows activation and conversion of methane to C[sub 2]+ hydrocarbons in a reducing atmosphere, thereby avoiding formation of oxides of carbon.

Maroni, V.A.; Iton, L.E.; Pasterczyk, J.W.; Winterer, M.; Krause, T.R.

1994-04-26T23:59:59.000Z

18

Transition metal sulfide loaded catalyst  

DOE Patents (OSTI)

A zeolite based catalyst for activation and conversion of methane. A zeolite support includes a transition metal (Mo, Cr or W) sulfide disposed within the micropores of the zeolite. The catalyst allows activation and conversion of methane to C.sub.2 + hydrocarbons in a reducing atmosphere, thereby avoiding formation of oxides of carbon.

Maroni, Victor A. (Naperville, IL); Iton, Lennox E. (Downers Grove, IL); Pasterczyk, James W. (Westmont, IL); Winterer, Markus (Westmont, IL); Krause, Theodore R. (Lisle, IL)

1994-01-01T23:59:59.000Z

19

Process for fabrication of metal oxide films  

DOE Patents (OSTI)

This invention is comprised of a method of fabricating metal oxide films from a plurality of reactants by inducing a reaction by plasma deposition among the reactants. The plasma reaction is effective for consolidating the reactants and producing thin films of metal oxides, e.g. electro-optically active transition metal oxides, at a high deposition rate. The presence of hydrogen during the plasma reaction enhances the deposition rate of the metal oxide. Various types of metal oxide films can be produced.

Tracy, C.E.; Benson, D.; Svensson, S.

1990-07-17T23:59:59.000Z

20

Semiconducting Transition-Metal Oxides Based on D5 Cations: Theory for MnO and Fe2O3  

SciTech Connect

Transition-metal oxides with partially filled d shells are typically Mott or charge-transfer insulators with notoriously poor transport properties due to large effective electron/hole masses or due to carrier self-trapping. Employing band-structure calculations and ab initio small-polaron theory for MnO and Fe{sub 2}O{sub 3}, we explore the potential of d{sup 5} oxides for achieving desirable semiconducting properties, e.g., in solar energy applications. The quantification of self-trapping energies and the trends with the coordination symmetry suggest strategies to overcome the main bottlenecks, i.e., the tendency for self-trapping of holes due to Mn(II) and of electrons due to Fe(III).

Peng, H.; Lany, S.

2012-05-15T23:59:59.000Z

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

NLE Websites -- All DOE Office Websites (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.

22

Fluorescence-based detection methodologies for nitric oxide using transition metal scaffolds  

E-Print Network (OSTI)

Chapter 1. Fluorescence-Based Detection Methodologies for Nitric Oxide: A Review. Chapter 2. Cobalt Chemistry with Mixed Aminotroponimine Salicylaldimine Ligands: Synthesis, Characterization, and Nitric Oxide Reactivity. ...

Hilderbrand, Scott A. (Scott Alan), 1976-

2004-01-01T23:59:59.000Z

23

Ab initio screening of lithium diffusion rates in transition metal oxide cathodes for lithium ion batteries  

E-Print Network (OSTI)

A screening metric for diffusion limitations in lithium ion battery cathodes is derived using transition state theory and common materials properties. The metric relies on net activation barrier for lithium diffusion. ...

Moore, Charles J. (Charles Jacob)

2012-01-01T23:59:59.000Z

24

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

25

The detection of nitric oxide and its reactivity with transition metal thiolate complexes  

E-Print Network (OSTI)

Nitric oxide (NO) is a molecule that is essential for life and regulates both beneficial and harmful processes. Because this gaseous radical influences many aspects of health and disease, we wish to explore the relationship ...

Tennyson, Andrew Gregory

2008-01-01T23:59:59.000Z

26

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

27

Method for dry etching of transition metals  

DOE Patents (OSTI)

A method for dry etching of transition metals. The method for dry etching of a transition metal (or a transition metal alloy such as a silicide) on a substrate comprises providing at least one nitrogen- or phosphorous-containing .pi.-acceptor ligand in proximity to the transition metal, and etching the transition metal to form a volatile transition metal/.pi.-acceptor ligand complex. The dry etching may be performed in a plasma etching system such as a reactive ion etching (RIE) system, a downstream plasma etching system (i.e. a plasma afterglow), a chemically-assisted ion beam etching (CAIBE) system or the like. The dry etching may also be performed by generating the .pi.-acceptor ligands directly from a ligand source gas (e.g. nitrosyl ligands generated from nitric oxide), or from contact with energized particles such as photons, electrons, ions, atoms, or molecules. In some preferred embodiments of the present invention, an intermediary reactant species such as carbonyl or a halide ligand is used for an initial chemical reaction with the transition metal, with the intermediary reactant species being replaced at least in part by the .pi.-acceptor ligand for forming the volatile transition metal/.pi.-acceptor ligand complex.

Ashby, Carol I. H. (Edgewood, NM); Baca, Albert G. (Albuquerque, NM); Esherick, Peter (Albuquerque, NM); Parmeter, John E. (Albuquerque, NM); Rieger, Dennis J. (Tijeras, NM); Shul, Randy J. (Albuquerque, NM)

1998-01-01T23:59:59.000Z

28

Method for dry etching of transition metals  

DOE Patents (OSTI)

A method for dry etching of transition metals is disclosed. The method for dry etching of a transition metal (or a transition metal alloy such as a silicide) on a substrate comprises providing at least one nitrogen- or phosphorus-containing {pi}-acceptor ligand in proximity to the transition metal, and etching the transition metal to form a volatile transition metal/{pi}-acceptor ligand complex. The dry etching may be performed in a plasma etching system such as a reactive ion etching (RIE) system, a downstream plasma etching system (i.e. a plasma afterglow), a chemically-assisted ion beam etching (CAIBE) system or the like. The dry etching may also be performed by generating the {pi}-acceptor ligands directly from a ligand source gas (e.g. nitrosyl ligands generated from nitric oxide), or from contact with energized particles such as photons, electrons, ions, atoms, or molecules. In some preferred embodiments of the present invention, an intermediary reactant species such as carbonyl or a halide ligand is used for an initial chemical reaction with the transition metal, with the intermediary reactant species being replaced at least in part by the {pi}-acceptor ligand for forming the volatile transition metal/{pi}-acceptor ligand complex.

Ashby, C.I.H.; Baca, A.G.; Esherick, P.; Parmeter, J.E.; Rieger, D.J.; Shul, R.J.

1998-09-29T23:59:59.000Z

29

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

Science Conference Proceedings (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

30

Metal atom oxidation laser  

DOE Patents (OSTI)

A chemical laser which operates by formation of metal or carbon atoms and reaction of such atoms with a gaseous oxidizer in an optical resonant cavity is described. The lasing species are diatomic or polyatomic in nature and are readily produced by exchange or other abstraction reactions between the metal or carbon atoms and the oxidizer. The lasing molecules may be metal or carbon monohalides or monoxides. (auth)

Jensen, R.J.; Rice, W.W.; Beattie, W.H.

1975-10-28T23:59:59.000Z

31

Metal atom oxidation laser  

DOE Patents (OSTI)

A chemical laser which operates by formation of metal or carbon atoms and reaction of such atoms with a gaseous oxidizer in an optical resonant cavity is described. The lasing species are diatomic or polyatomic in nature and are readily produced by exchange or other abstraction reactions between the metal or carbon atoms and the oxidizer. The lasing molecules may be metal or carbon monohalides or monoxides.

Jensen, R.J.; Rice, W.W.; Beattie, W.H.

1975-10-28T23:59:59.000Z

32

Extracting metals directly from metal oxides  

DOE Patents (OSTI)

A method of extracting metals directly from metal oxides by exposing the oxide to a supercritical fluid solvent containing a chelating agent is described. Preferably, the metal is an actinide or a lanthanide. More preferably, the metal is uranium, thorium or plutonium. The chelating agent forms chelates that are soluble in the supercritical fluid, thereby allowing direct removal of the metal from the metal oxide. In preferred embodiments, the extraction solvent is supercritical carbon dioxide and the chelating agent is selected from the group consisting of .beta.-diketones, halogenated .beta.-diketones, phosphinic acids, halogenated phosphinic acids, carboxylic acids, halogenated carboxylic acids, and mixtures thereof. In especially preferred embodiments, at least one of the chelating agents is fluorinated. The method provides an environmentally benign process for removing metals from metal oxides without using acids or biologically harmful solvents. The chelate and supercritical fluid can be regenerated, and the metal recovered, to provide an economic, efficient process.

Wai, Chien M. (Moscow, ID); Smart, Neil G. (Moscow, ID); Phelps, Cindy (Moscow, ID)

1997-01-01T23:59:59.000Z

33

Extracting metals directly from metal oxides  

DOE Patents (OSTI)

A method of extracting metals directly from metal oxides by exposing the oxide to a supercritical fluid solvent containing a chelating agent is described. Preferably, the metal is an actinide or a lanthanide. More preferably, the metal is uranium, thorium or plutonium. The chelating agent forms chelates that are soluble in the supercritical fluid, thereby allowing direct removal of the metal from the metal oxide. In preferred embodiments, the extraction solvent is supercritical carbon dioxide and the chelating agent is selected from the group consisting of {beta}-diketones, halogenated {beta}-diketones, phosphinic acids, halogenated phosphinic acids, carboxylic acids, halogenated carboxylic acids, and mixtures thereof. In especially preferred embodiments, at least one of the chelating agents is fluorinated. The method provides an environmentally benign process for removing metals from metal oxides without using acids or biologically harmful solvents. The chelate and supercritical fluid can be regenerated, and the metal recovered, to provide an economic, efficient process. 4 figs.

Wai, C.M.; Smart, N.G.; Phelps, C.

1997-02-25T23:59:59.000Z

34

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

35

MESOPOROUS METAL OXIDE MICROSPHERE ELECTRODE COMPOSITIONS AND ...  

Compositions and methods of making are provided for mesoporous metal oxide microspheres electrodes. The mesoporous metal oxide microsphere ...

36

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

37

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

SciTech Connect

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

38

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

39

Nanostructured Metal Oxide Anodes (Presentation)  

DOE Green Energy (OSTI)

This summarizes NREL's FY09 battery materials research activity in developing metal oxide nanostructured anodes to enable high-energy, durable and affordable li-ion batteries for HEVs and PHEVs.

Dillon, A. C.; Riley, L. A.; Lee, S.-H.; Kim, Y.-H.; Ban, C.; Gillaspie, D. T.; Pesaran, A.

2009-05-01T23:59:59.000Z

40

Nanostructured Metal Oxide Anodes (Presentation)  

SciTech Connect

This summarizes NREL's FY09 battery materials research activity in developing metal oxide nanostructured anodes to enable high-energy, durable and affordable li-ion batteries for HEVs and PHEVs.

Dillon, A. C.; Riley, L. A.; Lee, S.-H.; Kim, Y.-H.; Ban, C.; Gillaspie, D. T.; Pesaran, A.

2009-05-01T23:59:59.000Z

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

METAL OXIDE NANOPARTICLES  

SciTech Connect

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

42

Metal oxide porous ceramic membranes with small pore sizes  

DOE Patents (OSTI)

A method is disclosed for the production of metal oxide ceramic membranes of very small pore size. The process is particularly useful in the creation of titanium and other transition metal oxide membranes. The method utilizes a sol-gel process in which the rate of particle formation is controlled by substituting a relatively large alcohol in the metal alkoxide and by limiting the available water. Stable, transparent metal oxide ceramic membranes are created having a narrow distribution of pore size, with the pore diameter being manipulable in the range of 5 to 40 Angstroms.

Anderson, Marc A. (Madison, WI); Xu, Qunyin (Madison, WI)

1992-01-01T23:59:59.000Z

43

Metal oxide porous ceramic membranes with small pore sizes  

DOE Patents (OSTI)

A method is disclosed for the production of metal oxide ceramic membranes of very small pore size. The process is particularly useful in the creation of titanium and other transition metal oxide membranes. The method utilizes a sol-gel process in which the rate of particle formation is controlled by substituting a relatively large alcohol in the metal alkoxide and by limiting the available water. Stable, transparent metal oxide ceramic membranes are created having a narrow distribution of pore size, with the pore diameter being manipulable in the range of 5 to 40 Angstroms.

Anderson, Marc A. (Madison, WI); Xu, Qunyin (Madison, WI)

1991-01-01T23:59:59.000Z

44

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

45

Machinable dissolved metal oxide superconductors  

DOE Patents (OSTI)

Powders of a metal oxide superconductor are mixed with sufficient amount (10--80 mol%) of In, Sn, and/or Al, to become nonbrittle, machinable. Preferred superconductors are YBa[sub 2]Cu[sub 3]O[sub 7[minus]x] and Bi-Sr-Ca-Cu-O compounds.

Chen, Chung-Hsuan.

1991-01-01T23:59:59.000Z

46

Machinable dissolved metal oxide superconductors  

DOE Patents (OSTI)

Powders of a metal oxide superconductor are mixed with sufficient amount (10--80 mol%) of In, Sn, and/or Al, to become nonbrittle, machinable. Preferred superconductors are YBa{sub 2}Cu{sub 3}O{sub 7{minus}x} and Bi-Sr-Ca-Cu-O compounds.

Chen, Chung-Hsuan

1991-12-31T23:59:59.000Z

47

Method of boronizing transition metal surfaces  

SciTech Connect

A method is presented for preparing a boride layer on a transition metal substrate for use in corrosive environments or as a harden surface in machine applications. This method is particularly useful in treating current collectors for use within a high temperature and corrosive electrochemical cell environment. A melt of a alkali metal boride tetrafluoride salt including such as KF to lower its melting point is prepared including a dissolved boron containing material, for instance NiB, MnB.sub.2, or CrB.sub.2. A transition metal to be coated is immersed in the melt at a temperature of no more than 700.degree. C. and a surface boride layer of that transition metal is formed within a period of about 24 hours on the substrate surface.

Koyama, Koichiro (Hyogo, JP); Shimotake, Hiroshi (Hinsdale, IL)

1983-01-01T23:59:59.000Z

48

Method of boronizing transition-metal surfaces  

DOE Green Energy (OSTI)

A method is presented for preparing a boride layer on a transition metal substrate for use in corrosive environments or as a harden surface in machine applications. This method is particularly useful in treating current collectors for use within a high temperature and corrosive electrochemical cell environment. A melt of a alkali metal boride tetrafluoride salt including such as KF to lower its melting point is prepared including a dissolved boron containing material, for instance NiB, MnB/sub 2/, or CrB/sub 2/. A transition metal to be coated is immersed in the melt at a temperature of no more than 700/sup 0/C and a surface boride layer of that transition metal is formed within a period of about 24 hours on the substrate surface.

Koyama, K.; Shimotake, H.

1981-08-28T23:59:59.000Z

49

Ammonia release method for depositing metal oxides  

DOE Patents (OSTI)

A method of depositing metal oxides on substrates which is indifferent to the electrochemical properties of the substrates and which comprises forming ammine complexes containing metal ions and thereafter effecting removal of ammonia from the ammine complexes so as to permit slow precipitation and deposition of metal oxide on the substrates.

Silver, G.L.; Martin, F.S.

1993-12-31T23:59:59.000Z

50

Metal oxide composite dosimeter method and material  

DOE Patents (OSTI)

The present invention is a method of measuring a radiation dose wherein a radiation responsive material consisting essentially of metal oxide is first exposed to ionizing radiation. The metal oxide is then stimulating with light thereby causing the radiation responsive material to photoluminesce. Photons emitted from the metal oxide as a result of photoluminescence may be counted to provide a measure of the ionizing radiation.

Miller, Steven D. (Richland, WA)

1998-01-01T23:59:59.000Z

51

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

52

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

53

Metal Current Collector Protected by Oxide Film  

For Industry; For Researchers; Success Stories; About Us; ... metal felt made substantially of inexpensive ferritic steel coated with a thin oxide film, ...

54

Reduction of Metal Oxide to Metal using Ionic Liquids  

Science Conference Proceedings (OSTI)

A novel pathway for the high efficiency production of metal from metal oxide means of electrolysis in ionic liquids at low temperature was investigated. The main emphasis was to eliminate the use of carbon and high temperature application in the reduction of metal oxides to metals. The emphasis of this research was to produce metals such as Zn, and Pb that are normally produced by the application of very high temperatures. The reduction of zinc oxide to zinc and lead oxide to lead were investigated. This study involved three steps in accomplishing the final goal of reduction of metal oxide to metal using ionic liquids: 1) Dissolution of metal oxide in an ionic liquid, 2) Determination of reduction potential using cyclic voltammetry (CV) and 3) Reduction of the dissolved metal oxide. Ionic liquids provide additional advantage by offering a wide potential range for the deposition. In each and every step of the process, more than one process variable has been examined. Experimental results for electrochemical extraction of Zn from ZnO and Pb from PbO using eutectic mixtures of Urea ((NH2)2CO) and Choline chloride (HOC2H4N(CH3)3+Cl-) or (ChCl) in a molar ratio 2:1, varying voltage and temperatures were carried out. Fourier Transform Infra-Red (FTIR) spectroscopy studies of ionic liquids with and without metal oxide additions were conducted. FTIR and induction coupled plasma spectroscopy (ICPS) was used in the characterization of the metal oxide dissolved ionic liquid. Electrochemical experiments were conducted using EG&G potentiostat/galvanostat with three electrode cell systems. Cyclic voltammetry was used in the determination of reduction potentials for the deposition of metals. Chronoamperometric experiments were carried out in the potential range of -0.6V to -1.9V for lead and -1.4V to -1.9V for zinc. The deposits were characterized using XRD and SEM-EDS for phase, morphological and elemental analysis. The results showed that pure metal was deposited on the cathode. Successful extraction of metal from metal oxide dissolved in Urea/ChCl (2:1) was accomplished. The current efficiencies were relatively high in both the metal deposition processes with current efficiency greater than 86% for lead and 95% for zinc. This technology will advance the metal oxide reduction process by increasing the process efficiency and also eliminate the production of CO2 which makes this an environmentally benign technology for metal extraction.

Dr. Ramana Reddy

2012-04-12T23:59:59.000Z

55

(Electronic structure and reactivities of transition metal clusters)  

DOE Green Energy (OSTI)

The following are reported: theoretical calculations (configuration interaction, relativistic effective core potentials, polyatomics, CASSCF); proposed theoretical studies (clusters of Cu, Ag, Au, Ni, Pt, Pd, Rh, Ir, Os, Ru; transition metal cluster ions; transition metal carbide clusters; bimetallic mixed transition metal clusters); reactivity studies on transition metal clusters (reactivity with H{sub 2}, C{sub 2}H{sub 4}, hydrocarbons; NO and CO chemisorption on surfaces). Computer facilities and codes to be used, are described. 192 refs, 13 figs.

Not Available

1992-01-01T23:59:59.000Z

56

[Electronic structure and reactivities of transition metal clusters  

DOE Green Energy (OSTI)

The following are reported: theoretical calculations (configuration interaction, relativistic effective core potentials, polyatomics, CASSCF); proposed theoretical studies (clusters of Cu, Ag, Au, Ni, Pt, Pd, Rh, Ir, Os, Ru; transition metal cluster ions; transition metal carbide clusters; bimetallic mixed transition metal clusters); reactivity studies on transition metal clusters (reactivity with H{sub 2}, C{sub 2}H{sub 4}, hydrocarbons; NO and CO chemisorption on surfaces). Computer facilities and codes to be used, are described. 192 refs, 13 figs.

Not Available

1992-08-01T23:59:59.000Z

57

Single-layer transition metal sulfide catalysts  

SciTech Connect

Transition Metal Sulfides (TMS), such as molybdenum disulfide (MoS.sub.2), are the petroleum industry's "workhorse" catalysts for upgrading heavy petroleum feedstocks and removing sulfur, nitrogen and other pollutants from fuels. We have developed an improved synthesis technique to produce SLTMS catalysts, such as molybdenum disulfide, with potentially greater activity and specificity than those currently available. Applications for this technology include heavy feed upgrading, in-situ catalysis, bio-fuel conversion and coal liquefaction.

Thoma, Steven G. (Albuquerque, NM)

2011-05-31T23:59:59.000Z

58

Single-layer transition metal sulfide catalysts  

DOE Patents (OSTI)

Transition Metal Sulfides (TMS), such as molybdenum disulfide (MoS.sub.2), are the petroleum industry's "workhorse" catalysts for upgrading heavy petroleum feedstocks and removing sulfur, nitrogen and other pollutants from fuels. We have developed an improved synthesis technique to produce SLTMS catalysts, such as molybdenum disulfide, with potentially greater activity and specificity than those currently available. Applications for this technology include heavy feed upgrading, in-situ catalysis, bio-fuel conversion and coal liquefaction.

Thoma, Steven G. (Albuquerque, NM)

2011-05-31T23:59:59.000Z

59

Nanocomposite of graphene and metal oxide materials  

SciTech Connect

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

60

Metal-insulator transition in holography  

E-Print Network (OSTI)

We exhibit an interaction-driven metal-insulator quantum phase transition in a holographic model. Use of a helical lattice enables us to break translation invariance while preserving homogeneity. The metallic phase is characterized by a sharp Drude peak and a d.c. resistivity that increases with temperature. In the insulating phase the Drude spectral weight is transferred into a `mid-infrared' peak and to energy scales of order the chemical potential. The d.c. resistivity now decreases with temperature. In the metallic phase, operators breaking translation invariance are irrelevant at low energy scales. In the insulating phase, translation symmetry breaking effects are present at low energies. We find the near horizon extremal geometry that captures the insulating physics.

Aristomenis Donos; Sean A. Hartnoll

2012-12-12T23:59:59.000Z

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

Method for making monolithic metal oxide aerogels  

DOE Patents (OSTI)

Transparent, monolithic metal oxide aerogels of varying densities are produced using a method in which a metal alkoxide solution and a catalyst solution are prepared separately and reacted. The resulting hydrolyzed-condensed colloidal solution is gelled, and the wet gel is contained within a sealed, but gas permeable, containment vessel during supercritical extraction of the solvent. The present invention is especially advantageous for making metal oxides other than silica that are prone to forming opaque, cracked aerogels.

Droege, Michael W. (Livermore, CA); Coronado, Paul R. (Livermore, CA); Hair, Lucy M. (Livermore, CA)

1995-01-01T23:59:59.000Z

62

Method for making monolithic metal oxide aerogels  

DOE Patents (OSTI)

Transparent, monolithic metal oxide aerogels of varying densities are produced using a method in which a metal alkoxide solution and a catalyst solution are prepared separately and reacted. The resulting hydrolyzed-condensed colloidal solution is gelled, and the wet gel is contained within a sealed, but gas permeable, containment vessel during supercritical extraction of the solvent. The present invention is especially advantageous for making metal oxides other than silica that are prone to forming opaque, cracked aerogels. 6 figs.

Droege, M.W.; Coronado, P.R.; Hair, L.M.

1995-03-07T23:59:59.000Z

63

Transition-metal-doped chalcogenide lasers  

Science Conference Proceedings (OSTI)

Broadly tunable mid-infrared lasers are desirable for a number of scientific, remote-sensing, and military applications. Recently, Cr2+-doped chalcogenide lasers have emerged as an attractive source of tunable laser radiation in the 2-3.4-µm ... Keywords: Cr:CdMnTe, Cr:CdSe, Cr:ZnS, Cr:ZnSe, Fe:ZnSe, chalcogenide, continuous-wave laser, diode-pumped solid-state laser, mode-locked laser, solid-state laser, transition-metal ion

Timothy J. Carrig

2002-07-01T23:59:59.000Z

64

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

65

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

66

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

67

Process for etching mixed metal oxides  

DOE Patents (OSTI)

An etching process is described 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 Angstrom range may be achieved by this method. 1 fig.

Ashby, C.I.H.; Ginley, D.S.

1994-10-18T23:59:59.000Z

68

Method for making monolithic metal oxide aerogels  

DOE Patents (OSTI)

Transparent, monolithic metal oxide aerogels of varying densities are produced using a method in which a metal alkoxide solution and a catalyst solution are prepared separately and reacted. The resulting hydrolyzed-condensed colloidal solution is gelled, and the wet gel is contained within a sealed, but gas permeable, containment vessel during supercritical extraction of the solvent. The containment vessel is enclosed within an aqueous atmosphere that is above the supercritical temperature and pressure of the solvent of the metal alkoxide solution.

Coronado, Paul R. (Livermore, CA)

1999-01-01T23:59:59.000Z

69

Mg-Transition Metal Mirrors - Lawrence Berkeley National Laboratory  

mixed metal thin films containing magnesium and first -row transition ... The dotted line indicates ... Mg K -edge EXAFS transmission spectra of ...

70

The Organometallic Chemistry of the Transition Metals, Fourth ... - TMS  

Science Conference Proceedings (OSTI)

The Organometallic Chemistry of the Transition Metals by Professor Robert Crabtree is one impressive and compressive book. It is very professionally done.

71

TRANSITION METAL CATALYZED BIOMASS CONVERSION AND POLYMER SYNTHESIS.  

E-Print Network (OSTI)

??I have mainly worked on two areas during my graduate study in Dr. Ayusman Sen’s group. One is about transition metal catalyzed biomass conversion to… (more)

Yang, Weiran

2010-01-01T23:59:59.000Z

72

Structure Sensitivity of Methanol Electrooxidation on Transition Metals  

DOE Green Energy (OSTI)

We have investigated the structure sensitivity of methanol electrooxidation on eight transition metals (Au, Ag, Cu, Pt, Pd, Ir, Rh, and Ni) using periodic, self-consistent density functional theory (DFTGGA). Using the adsorption energies of 16 intermediates on two different facets of these eight face-centeredcubic transition metals, combined with a simple electrochemical model, we address the differences in the reaction mechanism between the (111) and (100) facets of these metals. We investigate two separate mechanisms for methanol electrooxidation: one going through a CO* intermediate (the indirect pathway) and another that oxidizes methanol directly to CO2 without CO* as an intermediate (the direct pathway). A comparison of our results for the (111) and (100) surfaces explains the origin of methanol electrooxidation’s experimentally-established structure sensitivity on Pt surfaces. For most metals studied, on both the (111) and (100) facets, we predict that the indirect mechanism has a higher onset potential than the direct mechanism. Ni(111), Au(100), and Au(111) are the cases where the direct and indirect mechanisms have the same onset potential. For the direct mechanism, Rh, Ir, and Ni show a lower onset potential on the (111) facet, whereas Pt, Cu, Ag, and Au possess lower onset potential on the (100) facet. Pd(100) and Pd(111) have the same onset potential for the direct mechanism. These results can be rationalized by the stronger binding energy of adsorbates on the (100) facet versus the (111) facet. Using linear scaling relations, we establish reactivity descriptors for the (100) surface similar to those recently developed for the (111) surface; the free energies of adsorbed CO* and OH* can describe methanol electrooxidation trends on various metal surfaces reasonably well.

Ferrin, Peter A.; Mavrikakis, Manos

2009-10-14T23:59:59.000Z

73

Activation of methane by transition metal-substituted aluminophosphate molecular sieves  

DOE Patents (OSTI)

Aluminophosphate molecular sieves substituted with cobalt, manganese or iron and having the AlPO.sub.4 -34 or AlPO.sub.4 -5, or related AlPO.sub.4 structure activate methane starting at approximately 350.degree. C. Between 400.degree. and 500.degree. C. and at methane pressures .ltoreq.1 atmosphere the rate of methane conversion increases steadily with typical conversion efficiencies at 500.degree. C. approaching 50% and selectivity to the production of C.sub.2+ hydrocarbons approaching 100%. The activation mechanism is based on reduction of the transition metal(III) form of the molecular sieve to the transition metal(II) form with accompanying oxidative dehydrogenation of the methane. Reoxidation of the - transition metal(II) form to the transition metal(III) form can be done either chemically (e.g., using O.sub.2) or electrochemically.

Iton, Lennox E. (Downers Grove, IL); Maroni, Victor A. (Naperville, IL)

1991-01-01T23:59:59.000Z

74

Aromaticity and Antiaromaticity in Transition-Metal Systems  

SciTech Connect

Aromaticity is an important concept in chemistry primarily for hydrocarbon compounds, but it has been extended to compounds containing transition-metal atoms. Recent findings of aromaticity and antiaromaticy in all-metal clusters have stimulated further researches in describing the chemical bonding, structures, and stability in transition-metal clusters and compounds on the basis of aromaticity and antiaromaticity, which are reviewed here. The presence of d-orbitals endows much more diverse chemistry, structure, and chemical bonding to transition-metal clusters and compounds. One interesting feature is the existence of a new type of ?-aromaticity, in addition to ?- and ?-aromaticity that are only possible for main group compounds. Another striking characteristic in the chemical bonding of transition-metal systems is the multi-fold nature of aromaticity, antiaromaticity, or even conflicting aromaticity. Separate sets of counting rules have been proposed for cyclic transition-metal systems to account for the three types of ?-, ?-, and ?-aromaticity/antiaromaticity. The diverse transition-metal clusters and compounds reviewed here indicate that multiple aromaticity and antiaromaticity may be much more common in chemistry than one would anticipate. It is hoped that the current review will stimulate interest in further understanding the structure and bonding, on the basis of aromaticity and antiaromaticity, of other known or unknown transition-metal systems, such as the active sites of enzymes or other biomolecules, which contain transition-metal atoms and clusters.

Zubarev, Dmitry Y.; Averkiev, Boris B.; Zhai, Hua Jin; Wang, Lai S.; Boldyrev, Alexander I.

2008-01-14T23:59:59.000Z

75

Magnetism In 3d Transition Metals at High Pressures  

SciTech Connect

This research project examined the changes in electronic and magnetic properties of transition metals and oxides under applied pressures, focusing on complex relationship between magnetism and phase stability in these correlated electron systems. As part of this LDRD project, we developed new measurement techniques and adapted synchrotron-based electronic and magnetic measurements for use in the diamond anvil cell. We have performed state-of-the-art X-ray spectroscopy experiments at the dedicated high-pressure beamline HP-CAT (Sector 16 Advanced Photon Source, Argonne National Laboratory), maintained in collaboration with of University of Nevada, Las Vegas and Geophysical Laboratory of The Carnegie Institution of Washington. Using these advanced measurements, we determined the evolution of the magnetic order in the ferromagnetic 3d transition metals (Fe, Co and Ni) under pressure, and found that at high densities, 3d band broadening results in diminished long range magnetic coupling. Our experiments have allowed us to paint a unified picture of the effects of pressure on the evolution of magnetic spin in 3d electron systems. The technical and scientific advances made during this LDRD project have been reported at a number of scientific meetings and conferences, and have been submitted for publication in technical journals. Both the technical advances and the physical understanding of correlated systems derived from this LDRD are being applied to research on the 4f and 5f electron systems under pressure.

Iota, V

2006-02-09T23:59:59.000Z

76

Method of making metal oxide ceramic membranes with small pore sizes  

DOE Patents (OSTI)

A method for the production of metal oxide ceramic membranes is composed of very small pore size. The process is particularly useful in the creation of titanium and other transition metal oxide membranes. The method utilizes a sol-gel process in which the rate of particle formation is controlled by substituting a relatively large alcohol in the metal alkoxide and by limiting the available water. Stable, transparent metal oxide ceramic membranes are created having a narrow distribution of pore size, with the pore diameter being manipulable in the range of 5 to 40 Angstroms.

Anderson, Marc A. (Madison, WI); Xu, Qunyin (Madison, WI)

1992-01-01T23:59:59.000Z

77

Spectroscopic studies of metal growth on oxides  

E-Print Network (OSTI)

Metal/oxide chemistry and metal cluster growth on oxides are fundamental to our understanding of the catalytic activity and selectivity of metal catalysts, thus considerable research recently has addressed the physical and chemical properties of metal clusters on well-defined oxide surfaces. In this work, the nucleation and growth modes of Ag on TiO?(110)(1x1) and (1x2) surfaces, Ag on ultra-thin Al?O? films, and Au on ultra-thin SiO? films were studied by scanning tunneling microscopy (STM), low energy ion scattering spectroscopy (LEIS) and X-ray photoelectron spectroscopy (XPS). In general, Ag grows three-dimensionally (3D) on both TiO?(110) and Al?O? film at 300 K. The growth mode of Au at fractional monolayer coverages is quasi-two dimensional (2D); at higher coverages, three-dimensional growth of Au was found. In these three systems, Ag/TiO?, Ag/Al?O?, and Au/SiO?, no strong chemical interaction was observed between metal clusters and substrates. Sintering was observed for all metal clusters upon annealing. A non-zero order desorption was observed for Ag/Al?O? and Au/SiO? in temperature programmed desorption (TPD) studies. The desorption activation energies decrease with decreasing metal coverages.

Luo, Kai

2000-01-01T23:59:59.000Z

78

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

Science Conference Proceedings (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).

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

79

Reduction of metal oxides through mechanochemical processing  

DOE Patents (OSTI)

The low temperature reduction of a metal oxide using mechanochemical processing techniques. The reduction reactions are induced mechanically by milling the reactants. In one embodiment of the invention, titanium oxide TiO.sub.2 is milled with CaH.sub.2 to produce TiH.sub.2. Low temperature heat treating, in the range of 400.degree. C. to 700.degree. C., can be used to remove the hydrogen in the titanium hydride.

Froes, Francis H. (Moscow, ID); Eranezhuth, Baburaj G. (Moscow, ID); Senkov, Oleg N. (Moscow, ID)

2000-01-01T23:59:59.000Z

80

Mechanistic aspects of photooxidation of polyhydroxylated molecules on metal oxides.  

Science Conference Proceedings (OSTI)

Polyhydroxylated molecules, including natural carbohydrates, are known to undergo photooxidation on wide-gap transition-metal oxides irradiated by ultraviolet light. In this study, we examine mechanistic aspects of this photoreaction on aqueous TiO{sub 2}, {alpha}-FeOOH, and {alpha}-Fe{sub 2}O{sub 3} particles using electron paramagnetic resonance (EPR) spectroscopy and site-selective deuteration. We demonstrate that the carbohydrates are oxidized at sites involved in the formation of oxo bridges between the chemisorbed carbohydrate molecule and metal ions at the oxide surface. This bridging inhibits the loss of water (which is the typical reaction of the analogous free radicals in bulk solvent) promoting instead a rearrangement that leads to elimination of the formyl radical. For natural carbohydrates, the latter reaction mainly involves carbon-1, whereas the main radical products of the oxidation are radical arising from H atom loss centered on carbon-1, -2, and -3 sites. Photoexcited TiO{sub 2} oxidizes all of the carbohydrates and polyols, whereas {alpha}-FeOOH oxidizes some of the carbohydrates, and {alpha}-Fe{sub 2}O{sub 3} is unreactive. These results serve as a stepping stone for understanding the photochemistry on mineral surfaces of more complex biomolecules such as nucleic acids.

Shkrob, I. A.; Marin, T. M.; Sevilla, M. D.; Chemerisov, S. (Chemical Sciences and Engineering Division); (Benedictine Univ.); (Oakland Univ.)

2011-03-24T23:59:59.000Z

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

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

82

Desulfurization with transition metal catalysts. Quarterly summary  

SciTech Connect

The overall objective of this research is to develop desulfurizing transition metal catalysts, which are active in homogeneous media at moderate temperatures and pressures for the purification of coal-derived fuels and chemicals. To this end, the mechanism of action is being examined whereby newly identified nickel(0) complexes desulfurize organosulfur compounds in solution at 65 to 70/sup 0/C. The sulfur compounds under investigation are typical of those commonly encountered in coal-derived liquids and solids, such as thiophenes, sulfides and mercaptans. The following studies on the homogeneous, stoichiometric desulfurizing agent, bis(1,5-cyclooctadiene) nickel(0) ((COD)/sub 2/Ni), were continued: (a) activation of the agent by means of added mono-, bi-/sup 2/ and tri-dentate amines, either of the tertiary or primary amine type; (b) labeling studies designed to reveal the source of the hydrogen that replaces the sulfur in the desulfurization of dibenzothiophene; (c) comparison of the desulfurizing activity of (COD)/sub 2/Ni, both in the presence and in the absence of lithium aluminum hydride; and (d) testing for the role of any biphenylene intermediate in these desulfurizations. Results are reported.

Eisch, J J

1980-04-10T23:59:59.000Z

83

Oxidation Behavior of Metallic Glass - Programmaster.org  

Science Conference Proceedings (OSTI)

Symposium, M. Bulk Metallic Glasses, Nanocrystalline Materials, and ... Application of Metallic Glass for High Performance Si Solar Cell: Oxidation Behavior of ...

84

Template synthesis and surface modification of metal oxides.  

E-Print Network (OSTI)

??Porous metal oxide monoliths, specifically silica, titania, zirconia and mixed oxides containing aluminum and yttrium, were prepared in a one-pot synthesis. Macroporosity was induced using… (more)

Drisko, Glenna Lynn

2010-01-01T23:59:59.000Z

85

Tuning of the Metal-Insulator Transition via Alkali Adsorption  

NLE Websites -- All DOE Office Websites (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.

86

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

87

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.

Anderson, Marc A. (Madison, WI)

1994-01-01T23:59:59.000Z

88

Tin, Antimony, Bismuth, and Tellurium Lewis Acids in sigma-Accepting Ligands for Transition Metals  

E-Print Network (OSTI)

The interactions between ligands and transition metals have been an essential subject in inorganic chemistry. Other than the commonly known L-type (two-electron donors) and X-type ligands (one-electron donors), Z-type ligands (two-electron acceptors) have begun to surface in the past decade. Capable of drawing a pair of d-electrons away from a metal, Z-ligands affect the electronic structures of transition metals leading to fascinating properties as well as reactivity. In particular, recent advance in Z-ligand chemistry have resulted in the discovery of transition metal borane complexes featuring metal ? boron interactions. Owing to the presence of a metal ? boron interaction which stabilizes the low valent state, these complexes have been shown to activate small molecules such as H2, CO2, and CHCl3. Further, the concept of Z-ligand has been extended to s- and d-block Lewis acids. In spite of these achievements, Z-ligands that contain Group 14-16 elements as Lewis acids remain scarce and relatively unexplored. For this reason, we have launched a series of investigations targeting complexes with transition metal ? Group 14-16 interactions. These investigations have allowed us to synthesize a series of novel complexes with palladium, platinum, or gold as metallobasic late transition metals and tin, antimony, bismuth, and tellurium as Lewis acids. The transition metal ? Lewis acid interactions of these complexes, which are supported by o-phosphinophenylene, 1,8-naphthalenediyl or 8-quinolinyl buttresses, have been established experimentally and theoretically. Further, the reactivity of these complexes toward anions and oxidants has also been explored. These experiments have led to the discovery of tellurium-platinum complexes that sustain reversible two-electron redox processes including the photo-reductive elimination of chlorine. Other noteworthy outcomes of this research include the isolation of the first telluroxanyl-metal complex as well as the discovery of complexes with HgII ? SbV interactions.

Lin, Tzu-Pin

2012-08-01T23:59:59.000Z

89

Free Energies of Novel Metal Oxides and Metal Oxide Surfaces at ...  

Science Conference Proceedings (OSTI)

Abstract Scope, The deposition of metal oxides on nuclear fuel rods in ... melds first principles calculations with experimental free energies of formation, we have ... and Pressures using Thermodynamics Informed by Density Functional Theory.

90

Metal Oxide Semiconductor Nanoparticles Open the Door to ...  

Using metal oxide semiconductor nanoparticles to target and control biological molecules could fuel medical breakthroughs in many areas, including ...

91

Methanol tolerant oxygen reduction catalysts based on transition metal sulfides  

Science Conference Proceedings (OSTI)

The oxygen reduction activity and methanol tolerance of a range of transition metal sulfide electrocatalysts have been evaluated in half-cell experiments and in a liquid-feed solid polymer electrolyte direct methanol fuel cell. These catalysts were prepared in high surface area form by direct synthesis onto various surface-functionalized carbon blacks. Of the materials tested, mixed-metal catalysts based on ReRuS and MoRuS were observed to give the best oxygen reduction activities. In addition, significant increases in performance were observed when employing sulfur-functionalized carbon black, which were attributed to the preferential deposition of active Ru sites in the catalyst-preparation process. Although the intrinsic activity of the best material tested, namely, Mo{sub 2}Ru{sub 5}S{sub 5} on sulfur-treated XC-72, was lower than Pt (by ca. 1545 mV throughout the entire polarization curve), its activity relative to Pt increased significantly in methanol-contaminated electrolytes. This was due to methanol oxidation side reactions reducing the net activity of the Pt, especially at low overpotentials.

Reeve, R.W.; Christensen, P.A.; Hamnett, A.; Haydock, S.A.; Roy, S.C. [Univ. of Newcastle, Newcastle upon Tyne (United Kingdom). Dept. of Chemistry

1998-10-01T23:59:59.000Z

92

Femtosecond NEXAFS of Photoinduced Insulator-Metal Transition...  

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

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...

93

Nitrene transfer reactions by late transition metal complexes  

E-Print Network (OSTI)

This thesis presents nitrene transfer reactions that are catalyzed or mediated by late transition metal complexes. Sterically large, fluorinated supporting ligands are used to minimize potential side reactions. A new ...

Hamilton, Charles W., Ph. D. Massachusetts Institute of Technology

2007-01-01T23:59:59.000Z

94

Transition Metal Sulfide Electrocatalysts for PEM Fuel Cells  

NLE Websites -- All DOE Office Websites (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

Photochemical reductive elimination of halogen from transition metal complexes  

E-Print Network (OSTI)

This thesis is focused on the synthesis and study of transition metal complexes that undergo halogen elimination when irradiated with UV and visible light. This chemistry is relevant for solar energy storage schemes in ...

Cook, Timothy R. (Timothy Raymond), 1982-

2010-01-01T23:59:59.000Z

96

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

SciTech Connect

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

97

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

SciTech Connect

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

98

Impact Dynamics of Oxidized Liquid Metal Drops  

E-Print Network (OSTI)

With exposure to air, many liquid metals spontaneously generate an oxide layer on their surface. In oscillatory rheological tests, this skin is found to introduce a yield stress that typically dominates the elastic response but can be tuned by exposing the metal to hydrochloric acid solutions of different concentration. We systematically studied the normal impact of eutectic gallium-indium (eGaIn) drops under different oxidation conditions and show how this leads to two different dynamical regimes. At low impact velocity (or low Weber number), eGaIn droplets display strong recoil and rebound from the impacted surface when the oxide layer is removed. In addition, the degree of drop deformation or spreading during the impact is controlled by the oxide skin. We show that the scaling law known from ordinary liquids for the maximum spreading radius as a function of impact velocity can still be applied to the case of oxidized eGaIn if an effective Weber number $We^{\\star}$ is employed that uses an effective surface...

Xu, Qin; Jaeger, Heinrich M

2013-01-01T23:59:59.000Z

99

Reactor vessel 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.

Anderson, Marc A. (Madison, WI); Zeltner, Walter A. (Oregon, WI)

1992-08-11T23:59:59.000Z

100

Metal oxide and metal fluoride nanostructures and methods of making same  

SciTech Connect

The present invention includes pure single-crystalline metal oxide and metal fluoride nanostructures, and methods of making same. These nanostructures include nanorods and nanoarrays.

Wong, Stanislaus S. (Stony Brook, NY); Mao, Yuanbing (Los Angeles, CA)

2009-08-18T23:59:59.000Z

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

Thermal barrier and overlay coating systems comprising composite metal/metal oxide bond coating layers  

DOE Patents (OSTI)

The present invention generally describes multilayer coating systems comprising a composite metal/metal oxide bond coat layer. The coating systems may be used in gas turbines.

Goedjen, John G. (Oviedo, FL); Sabol, Stephen M. (Orlando, FL); Sloan, Kelly M. (Longwood, FL); Vance, Steven J. (Orlando, FL)

2001-01-01T23:59:59.000Z

102

Hydrous metal oxide catalysts for oxidation of hydrocarbons  

DOE Green Energy (OSTI)

This report describes work performed at Sandia under a CRADA with Shell Development of Houston, Texas aimed at developing hydrous metal oxide (HMO) catalysts for oxidation of hydrocarbons. Autoxidation as well as selective oxidation of 1-octene was studied in the presence of HMO catalysts based on known oxidation catalysts. The desired reactions were the conversion of olefin to epoxides, alcohols, and ketones, HMOs seem to inhibit autoxidation reactions, perhaps by reacting with peroxides or radicals. Attempts to use HMOs and metal loaded HMOs as epoxidation catalysts were unsuccessful, although their utility for this reaction was not entirely ruled out. Likewise, alcohol formation from olefins in the presence of HMO catalysts was not achieved. However, this work led to the discovery that acidified HMOs can lead to carbocation reactions of hydrocarbons such as cracking. An HMO catalyst containing Rh and Cu that promotes the reaction of {alpha}-olefins with oxygen to form methyl ketones was identified. Although the activity of the catalyst is relatively low and isomerization reactions of the olefin simultaneously occur, results indicate that these problems may be addressed by eliminating mass transfer limitations. Other suggestions for improving the catalyst are also made. 57 refs.

Miller, J.E.; Dosch, R.G.; McLaughlin, L.I. [Sandia National Labs., Albuquerque, NM (United States). Process Research Dept.

1993-07-01T23:59:59.000Z

103

Method for producing metal oxide aerogels  

DOE Patents (OSTI)

A two-step hydrolysis-condensation method was developed to form metal oxide aerogels of any density, including densities of less than 0.003g/cm{sup 3} and greater than 0.27g/cm{sup 3}. High purity metal alkoxide is reacted with water, alcohol solvent, and an additive to form a partially condensed metal intermediate. All solvent and reaction-generated alcohol is removed, and the intermediate is diluted with a nonalcoholic solvent. The intermediate can be stored for future use to make aerogels of any density. The aerogels are formed by reacting the intermediate with water, nonalcoholic solvent, and a catalyst, and extracting the nonalcoholic solvent directly. The resulting monolithic aerogels are hydrophobic and stable under atmospheric conditions, and exhibit good optical transparency, high clarity, and homogeneity. The aerogels have high thermal insulation capacity, high porosity, mechanical strength and stability, and require shorter gelation times than aerogels formed by conventional methods. 8 figs.

Tillotson, T.M.; Poco, J.F.; Hrubesh, L.W.; Thomas, I.M.

1995-04-25T23:59:59.000Z

104

Method for producing metal oxide aerogels  

SciTech Connect

A two-step hydrolysis-condensation method was developed to form metal oxide aerogels of any density, including densities of less than 0.003g/cm.sup.3 and greater than 0.27g/cm.sup.3. High purity metal alkoxide is reacted with water, alcohol solvent, and an additive to form a partially condensed metal intermediate. All solvent and reaction-generated alcohol is removed, and the intermediate is diluted with a nonalcoholic solvent. The intermediate can be stored for future use to make aerogels of any density. The aerogels are formed by reacting the intermediate with water, nonalcoholic solvent, and a catalyst, and extracting the nonalcoholic solvent directly. The resulting monolithic aerogels are hydrophobic and stable under atmospheric conditions, and exhibit good optical transparency, high clarity, and homogeneity. The aerogels have high thermal insulation capacity, high porosity, mechanical strength and stability, and require shorter gelation times than aerogels formed by conventional methods.

Tillotson, Thomas M. (Tracy, CA); Poco, John F. (Livermore, CA); Hrubesh, Lawrence W. (Pleasanton, CA); Thomas, Ian M. (Livermore, CA)

1995-01-01T23:59:59.000Z

105

Tuning of the Metal-Insulator Transition via Alkali Adsorption  

NLE Websites -- All DOE Office Websites (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.

106

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.; Wen, Shi-Jie

1998-12-01T23:59:59.000Z

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

Metal oxide membranes for gas separation  

DOE Patents (OSTI)

A method for permformation of a microporous ceramic membrane onto a porous support includes placing a colloidal suspension of metal oxide particles on one side of the porous support and exposing the other side of the porous support to a drying stream of gas or a reactive gas stream so that the particles are deposited on the drying side of the support as a gel. The gel so deposited can be sintered to form a supported ceramic membrane having mean pore sizes less than 30 Angstroms and useful for ultrafiltration, reverse osmosis, or gas separation.

Anderson, Marc A. (Madison, WI); Webster, Elizabeth T. (Madison, WI); Xu, Qunyin (Plainsboro, NJ)

1994-01-01T23:59:59.000Z

109

Metal oxide membranes for gas separation  

DOE Patents (OSTI)

A method for formation of a microporous ceramic membrane onto a porous support includes placing a colloidal suspension of metal oxide particles on one side of the porous support and exposing the other side of the porous support to a drying stream of gas or a reactive gas stream so that the particles are deposited on the drying side of the support as a gel. The gel so deposited can be sintered to form a supported ceramic membrane having mean pore sizes less than 30 Angstroms and useful for ultrafiltration, reverse osmosis, or gas separation. 4 figs.

Anderson, M.A.; Webster, E.T.; Xu, Q.

1994-08-30T23:59:59.000Z

110

On superconductivity of high-spin transition metal compounds  

SciTech Connect

The possibility of Cooper instability in transition metal compounds is established based of the concept of the strong interaction in the same unit cell. The multicomponent scattering amplitude of excitations is calculated. The superconductivity equations are derived for compounds of 3d transition metals. It is shown that in the pole approximation, the superconductivity equations can be reduced to the multicomponent superconductivity equations with preset BCS constants. A method is developed for calculating one-orbital constants and constants with different orbitals as functions of the total spin. The concentration ranges of superconducting ordering are obtained for one-orbital equations.

Zaitsev, R. O., E-mail: Zaitsev_rogdai@mail.ru [Moscow Institute of Physics and Technology (State University) (Russian Federation)

2011-11-15T23:59:59.000Z

111

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

112

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 that about /minus/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, V.A.; von Winbush, S.

1987-05-01T23:59:59.000Z

113

High temperature superconductivity in metallic region near Mott transition  

E-Print Network (OSTI)

The spin-singlet superconductivity without phonons is examined in consideration of correlations on an extended Hubbard model. It is shown that the superconductivity requires not only the total correlation should be strong enough but also the density of state around Fermi energy should be large enough, which shows that the high temperature superconductivity could only be found in the metallic region near the Mott metal insulator transition (MIT). Other properties of superconductors are also discussed on these conclusions.

Tian De Cao

2009-06-11T23:59:59.000Z

114

Kinetic Consequences of Chemisorbed Oxygen Atoms during Methane Oxidation on Group VIII Metal Clusters  

E-Print Network (OSTI)

v for the oxidation of bulk Pt metals. The bulk oxidation isbulk, cluster size and metal coordination effects on thermodynamic tendencies of bulk oxidation,O s * sites at metal surfaces. Bulk oxidation exposes Pd 2+

Chin, Ya Huei

2011-01-01T23:59:59.000Z

115

Near room temperature lithographically processed metal-oxide transistors  

E-Print Network (OSTI)

A fully lithographic process at near-room-temperature was developed for the purpose of fabricating transistors based on metal-oxide channel materials. The combination of indium tin oxide (ITO) as the source/drain electrodes, ...

Tang, Hui, M. Eng. Massachusetts Institute of Technology

2008-01-01T23:59:59.000Z

116

Metal Oxide Semiconductor Nanoparticles Pave the Way for ...  

Argonne researchers have developed a unique application of technology that involves using metal oxide semiconductor nanoparticles to target and control biological ...

117

Metal Oxide-Graphene Nanocomposites for Li-Ion Battery  

Science Conference Proceedings (OSTI)

Presentation Title, Metal Oxide-Graphene Nanocomposites for Li-Ion Battery. Author(s), Donghai Wang, Daiwon Choi, Juan Li, Zhenguo Yang, Zimin Nie, Rong ...

118

Flame Synthesized Metal Oxide Nanowires as Effective Photoanodes  

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

Stanford, CA 94305, USA I will discuss an atmospheric, cost-effective and scalable flame synthesis method for the growth and doping of metal oxide nanowires and these...

119

Activation of methane by transition metal-substituted aluminophosphate molecular sieves  

DOE Patents (OSTI)

Aluminophosphate molecular sieves substituted with cobalt, manganese or iron and having the AlPO{sub 4}-34 or AlPO{sub 4}-5, or related AlPO{sub 4} structure activate methane starting at approximately 350{degree}C. Between 400 and 500{degree}C and at methane pressures {le} 1 atmosphere the rate of methane conversion increases steadily with typical conversion efficiencies at 500{degree}C approaching 50% and selectivity to the production of C{sub 2+} hydrocarbons approaching 100%. The cobalt substituted AlPO{sub 4}-34 structure (CoAPSO-34) produces ethylene, ethane, propylene, and propane in varying proportions, depending on reaction conditions. The cobalt-substituted AlPO{sub 4}-5 (CoAPSO-5) produces polypropylene in very high yield, with ethane, ethylene, and propane also produced. The activation mechanism is based on reduction of the transition metal (III) from of the molecular sieve to the transition metal(II) form with accompanying oxidative dehydrogenation of the methane. Reoxidation of the transition metal(II) form to the transition metal (III) form can be done either chemically (e.g., using O{sub 2}) or electrochemically. 4 figs.

Iton, L.E.; Maroni, V.A.

1990-03-16T23:59:59.000Z

120

Conductive metal oxide film and method of making  

DOE Patents (OSTI)

The present invention is a method for reducing a dopant in a film of a metal oxide wherein the dopant is reduced and the first metal oxide is substantially not reduced. The method of the present invention relies upon exposing the film to reducing conditions for a predetermined time and reducing a valence of the metal from a positive valence to a zero valence and maintaining atoms with a zero valence in an atomic configuration within the lattice structure of the metal oxide. According to the present invention, exposure to reducing conditions may be achieved electrochemically or achieved in an elevated temperature gas phase.

Windisch, Jr., Charles F. (Kennewick, WA); Exarhos, Gregory J. (Richland, WA)

1999-01-01T23:59:59.000Z

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

Solder for oxide layer-building metals and alloys  

DOE Patents (OSTI)

A low-temperature solder and method for soldering an oxide layer-building metal such as Al, Ti, Ta or stainless steel. The composition comprises Sn and Zn; Ge as a wetting agent; preferably small amounts of Cu and Sb; and a grit, such as SiC. The grit abrades any oxide layer formed on the surface of the metal as the Ge penetrates beneath and loosens the oxide layer to provide good metal-to-metal contact. The Ge comprises less than 10 wt.% of the solder composition so that it provides sufficient wetting action but does not result in a melting temperature above 300 C. The method comprises the steps rubbing the solder against the metal surface so that the grit in the solder abrades the surface while heating the surface until the solder begins to melt and the germanium penetrates the oxide layer, then brushing aside any oxide layer loosened by the solder.

Kronberg, J.W.

1991-04-08T23:59:59.000Z

122

Cross-linking proteins with bimetallic tetracarboxylate compounds of transition metals  

DOE Patents (OSTI)

Stable cross-linked complexes of transition-metal tetracarboxylates and proteins are formed. The preferred transition-metal is rhodium. The protein may be collagen or an enzyme such as a proteolytic enzyme.

Kostic, Nenad M. (Ames, IA); Chen, Jian (Ames, IA)

1991-03-05T23:59:59.000Z

123

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

DOE Green Energy (OSTI)

Carbon-supported metal catalysts are widely used in heterogeneous catalysis and electrocatalysis. In this paper, we report a novel method to deposit metal catalysts and metal oxide nanoparticles on two-dimensional graphene sheets to improve the catalytic performance and stability of the catalyst materials. The new synthesis method allows indium tin oxide (ITO) nanocrystals to be directly grown on functionalized graphene sheets forming the ITO-graphene hybrids. Pt nanoparticles are then deposited to form a special triple-junction structure (Pt-ITO-graphene). Both experimental study and periodic density functional theory calculations show that the supported Pt nanoparticles are stable at Pt-ITO-graphene triple junction points. The new catalyst materials were tested for oxygen reduction for potential applications in polymer electrolyte membrane fuel cells, and they exhibited greatly enhanced stability and activity. The reasons for the high stability and activity of Pt-ITO-graphene are analyzed.

Kou, Rong; Shao, Yuyan; Mei, Donghai; Nie, Zimin; Wang, Donghai; Wang, Chong M.; Viswanathan, Vilayanur V.; Park, Seh K.; Aksay, Ilhan A.; Lin, Yuehe; Wang, Yong; Liu, Jun

2011-03-02T23:59:59.000Z

124

Metal-Insulator Transitions in Degenerate Hubbard Models and  

E-Print Network (OSTI)

Mott-Hubbard metal-insulator transitions in N-fold degenerate Hubbard models are studied within the Gutzwiller approximation. For any rational filling with x (integer) electrons per site it is found that metal-insulator transition occurs at a critical correlation energy Uc(N,x) = Uc(N,2N ? x) = ?(N,x)|¯?(N,x)|, where ¯? is the band energy per particle for the uncorrelated Fermi-liquid state and ?(N,x) is a geometric factor which increases linearly with x. We propose that the alkali metal doped fullerides AxC60 can be described by a 3-fold degenerate Hubbard model. Using the current estimate of band width and correlation energy this implies that most of AxC60, at integer x, are Mott-Hubbard insulators and A3C60 is a strongly correlated metal. PACS numbers: 71.10.+x,71.30.+h,74.70.W 1 Typeset using REVTEXThe discovery of superconductivity in A3C60 [1] has spurred great interest in alkali metal doped fullerides [2]. Beside A3C60, stable phases such as Rb1C60, Na2C60, K4C60 were

Jian Ping Lu

2008-01-01T23:59:59.000Z

125

A superconductor to superfluid phase transition in liquid metallic hydrogen  

E-Print Network (OSTI)

Although hydrogen is the simplest of atoms, it does not form the simplest of solids or liquids. Quantum effects in these phases are considerable (a consequence of the light proton mass) and they have a demonstrable and often puzzling influence on many physical properties, including spatial order. To date, the structure of dense hydrogen remains experimentally elusive. Recent studies of the melting curve of hydrogen indicate that at high (but experimentally accessible) pressures, compressed hydrogen will adopt a liquid state, even at low temperatures. In reaching this phase, hydrogen is also projected to pass through an insulator-to-metal transition. This raises the possibility of new state of matter: a near ground-state liquid metal, and its ordered states in the quantum domain. Ordered quantum fluids are traditionally categorized as superconductors or superfluids; these respective systems feature dissipationless electrical currents or mass flow. Here we report an analysis based on topological arguments of the projected phase of liquid metallic hydrogen, finding that it may represent a new type of ordered quantum fluid. Specifically, we show that liquid metallic hydrogen cannot be categorized exclusively as a superconductor or superfluid. We predict that, in the presence of a magnetic field, liquid metallic hydrogen will exhibit several phase transitions to ordered states, ranging from superconductors to superfluids.

Egor Babaev; Asle Sudbo; N. W. Ashcroft

2004-10-18T23:59:59.000Z

126

Reduction of spalling in mixed metal oxide desulfurization sorbents by addition of a large promoter metal oxide  

DOE Patents (OSTI)

Mixed metal oxide pellets for removing hydrogen sulfide from fuel gas mixes derived from coal are stabilized for operation over repeated cycles of desulfurization and regeneration reactions by addition of a large promoter metal oxide such as lanthanum trioxide. The pellets, which may be principally made up of a mixed metal oxide such as zinc titanate, exhibit physical stability and lack of spalling or decrepitation over repeated cycles without loss of reactivity. The lanthanum oxide is mixed with pellet-forming components in an amount of 1 to 10 weight percent.

Poston, James A. (Star City, WV)

1997-01-01T23:59:59.000Z

127

Reduction of spalling in mixed metal oxide desulfurization sorbents by addition of a large promoter metal oxide  

DOE Patents (OSTI)

Mixed metal oxide pellets for removing hydrogen sulfide from fuel gas mixtures derived from coal are stabilized for operation over repeated cycles of desulfurization and regeneration reactions by addition of a large promoter metal oxide such as lanthanum trioxide. The pellets, which may be principally made up of a mixed metal oxide such as zinc titanate, exhibit physical stability and lack of spalling or decrepitation over repeated cycles without loss of reactivity. The lanthanum oxide is mixed with pellet-forming components in an amount of 1 to 10 weight percent.

Poston, J.A.

1996-12-31T23:59:59.000Z

128

Selectivity of the reactions of oxygenates on transition metal surfaces  

Science Conference Proceedings (OSTI)

The goal of this research has been to understand, by means of surface science studies, the elementary processes involved in the synthesis of higher oxygenates on transition metals, and the dependence of these processes upon the nature of the surface. We have completed a considerable body of work (Ph.D. thesis of J. Lynn Davis, 1988) on the reactions of alcohols, aldehydes, and carboxylic acids on clean and oxygen-containing Pd(111) surfaces. Work during the past year has focused on the surface chemistry of rhodium. We find both interesting similarities and differences between rhodium and palladium. Comparison of the two sheds light on common reaction networks among the transition metals, and on the differences between them which permit control of selectivities in catalytic reactions.

Barteau, M.A.

1989-01-01T23:59:59.000Z

129

Anomalous oxidation reactions at noble metal surfaces at low potentials: With particular reference to palladium  

Science Conference Proceedings (OSTI)

Multilayer palladium hydrous oxide films, produced by potential cycling, were more stable in acid solution at 0 C (as compared with room temperature). The electrochemical responses for the reduction of such films were more consistent at the lower temperature and were remarkably similar to those of platinum under similar conditions. Both metals yield a hydrous oxide containing two components, HO1 and HO2. The cyclic voltammogram for the bare metal (Pd or Pt) in acid contains an unusual feature at low potentials in the absorbed hydrogen region. This feature, a low level reversible transition at ca. 0.24 V(RHE) for palladium, was reported in earlier independent work. It is attributed here to a premonolayer oxidation effect, i.e., an active metal atom/incipient hydrous oxide transition. The peak maximum potential (E{sub p}) for HO2 reduction in multilayer Pd hydrous oxide reduction experiments, on extrapolation to either very low sweep rates or low film thicknesses, gave a similar potential value. The relevance of this result to noble metal electrocatalysis is outlined. Electrocatalysis is a topic of major interest at the present time, especially in connection with fuel cell development.

Burke, L.D.; Buckley, D.T. [University College Cork (Ireland). Dept. of Chemistry

1996-03-01T23:59:59.000Z

130

P-64: A Comparative Study of Metal Oxide Coated Indium-tin Oxide Anodes  

E-Print Network (OSTI)

Indium-tin oxide anodes capped with certain oxides of metals enhance while other oxides degrade the hole-injection and quantum efficiencies of organic light-emitting diodes (OLEDs). The oxides of tin, zinc, praseodymium, yttrium, gallium, terbium and titanium have been investigated. The power efficiency of an OLED with a 1nm thick praseodymium oxide cap is improved by 2.5 times over that of a conventional OLED without an oxide capped anode.

For Organic Light-Emitting; Chengfeng Qiu; Haiying Chen; Zhilang Xie; Man Wong; Hoi Sing Kwok

2002-01-01T23:59:59.000Z

131

Catalysis using hydrous metal oxide ion exchangers  

DOE Patents (OSTI)

In a process which is catalyzed by a catalyst comprising an active metal on a carrier, said metal being active as a catalyst for the process, an improvement is provided wherein the catalyst is a hydrous, alkali metal or alkaline earth metal titanate, zirconate, niobate or tantalate wherein alkali or alkaline earth metal cations have been exchanged with a catalytically effective amount of cations of said metal.

Dosch, R.G.; Stephens, H.P.; Stohl, F.V.

1983-07-21T23:59:59.000Z

132

Catalysis using hydrous metal oxide ion exchanges  

DOE Patents (OSTI)

In a process which is catalyzed by a catalyst comprising an active metal on a carrier, said metal being active as a catalyst for the process, an improvement is provided wherein the catalyst is a hydrous, alkali metal or alkaline earth metal titanate, zirconate, niobate or tantalate wherein alkali or alkaline earth metal cations have been exchanged with a catalytically effective amount of cations of said metal.

Dosch, Robert G. (Albuquerque, NM); Stephens, Howard P. (Albuquerque, NM); Stohl, Frances V. (Albuquerque, NM)

1985-01-01T23:59:59.000Z

133

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

134

Formation of metal oxides by cathodic arc deposition  

DOE Green Energy (OSTI)

Metal oxide thin films are of interest for a number of applications. Cathodic arc deposition, an established, industrially applied technique for formation of nitrides (e.g. TiN), can also be used for metal oxide thin film formation. A cathodic arc plasma source with desired cathode material is operated in an oxygen atmosphere, and metal oxides of various stoichiometric composition can be formed on different substrates. We report here on a series of experiments on metal oxide formation by cathodic arc deposition for different applications. Black copper oxide has been deposited on ALS components to increase the radiative heat transfer between the parts. Various metal oxides such as tungsten oxide, niobium oxide, nickel oxide and vanadium oxide have been deposited on ITO glass to form electrochromic films for window applications. Tantalum oxide films are of interest for replacing polymer electrolytes. Optical waveguide structures can be formed by refractive index variation using oxide multilayers. We have synthesized multilayers of Al{sub 2}O{sub 3}/Y{sub 2}O{sub 3}/AI{sub 2}O{sub 3}/Si as possible basic structures for passive optoelectronic integrated circuits, and Al{sub 2-x}Er{sub x}O{sub 3} thin films with a variable Er concentration which is a potential component layer for the production of active optoelectronic integrated devices such as amplifiers or lasers at a wavelength of 1.53 {mu}m. Aluminum and chromium oxide films have been deposited on a number of substrates to impart improved corrosion resistance at high temperature. Titanium sub-oxides which are electrically conductive and corrosion resistant and stable in a number of aggressive environments have been deposited on various substrates. These sub-oxides are of great interest for use in electrochemical cells.

Anders, S.; Anders, A.; Rubin, M.; Wang, Z.; Raoux, S.; Kong, F.; Brown, I.G.

1995-03-01T23:59:59.000Z

135

Method for converting uranium oxides to uranium metal  

DOE Green Energy (OSTI)

A process is described for converting scrap and waste uranium oxide to uranium metal. The uranium oxide is sequentially reduced with a suitable reducing agent to a mixture of uranium metal and oxide products. The uranium metal is then converted to uranium hydride and the uranium hydride-containing mixture is then cooled to a temperature less than -100.degree. C. in an inert liquid which renders the uranium hydride ferromagnetic. The uranium hydride is then magnetically separated from the cooled mixture. The separated uranium hydride is readily converted to uranium metal by heating in an inert atmosphere. This process is environmentally acceptable and eliminates the use of hydrogen fluoride as well as the explosive conditions encountered in the previously employed bomb-reduction processes utilized for converting uranium oxides to uranium metal.

Duerksen, Walter K. (Norris, TN)

1988-01-01T23:59:59.000Z

136

Method for converting uranium oxides to uranium metal  

DOE Patents (OSTI)

A process is described for converting scrap and waste uranium oxide to uranium metal. The uranium oxide is sequentially reduced with a suitable reducing agent to a mixture of uranium metal and oxide products. The uranium metal is then converted to uranium hydride and the uranium hydride-containing mixtures is then cooled to a temperature less than -100/sup 0/C in an inert liquid which renders the uranium hydride ferromagnetic. The uranium hydride is then magnetically separated from the cooled mixture. The separated uranium hydride is readily converted to uranium metal by heating in an inert atmosphere. This process is environmentally acceptable and eliminates the use of hydrogen fluoride as well as the explosive conditions encountered in the previously employed bomb-reduction processes utilized for converting uranium oxides to uranium metal.

Duerksen, W.K.

1987-01-01T23:59:59.000Z

137

NREL Demonstrates Efficient Solar Water Splitting by Metal Oxide Photoabsorber (Fact Sheet)  

SciTech Connect

New development demonstrates that inexpensive and robust metal oxide photoabsorbers hold great promise as photoanodes for water oxidation.

Not Available

2014-01-01T23:59:59.000Z

138

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

DOE Green Energy (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

139

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

140

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

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

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

142

Solution-mediated strategies for synthesizing metal oxides, borates and phosphides using nanocrystals as reactive precursors  

E-Print Network (OSTI)

Because of their high surface area (and hence, increased reactivity) nanocrystals can be used as reactive precursors in the low-temperature synthesis of solid state materials. When nanocrystals are used as reactants, the temperatures needed for diffusion between them can be significantly lower than for bulk-scale reactions—often at temperatures attainable using solution-based techniques. In the following work, two synthetic strategies are defined and developed for accessing metal oxides, borates and phosphides using nanocrystalline precursors and solution-mediated techniques. Broadly, the strategies involve either 1) the formation of a nano-sized precursor in solution which is post-annealed after isolation to form a target metal oxide or borate or 2) the solution-mediated diffusion of phosphorus into a nanocrystalline metal to form target metal phosphides. To form multi-metal oxides using the first strategy, metal oxide nanoparticle precursors are mixed in stoichiometric ratios in solution to form a nanocomposite. After isolation, the nanocomposite is annealed in air at 700-800 °C to form target ternary metal oxides, including Y2Ti2O7, Eu2Ti2O7, NiTiO3, Zn2SnO4 and CuInO2. As a variation of this method, rare earth borate nanoparticle precursors can be formed in solution by the reaction of RE3+ with NaBH4. After isolation, annealing in air at 700-800 °C crystallizes a range of REBO3 and Al3RE(BO3)4 powders. Using solution-based techniques, metal phosphides can be formed by the reaction of pre-formed metal nanocrystals with trioctylphosphine (TOP), which acts as a mild phosphorus-source, at 300-370 °C. A range of transition metal phosphide nanocrystals are accessible using this strategy, including the polyphosphides PdP2, AgP2 and Au2P3. Furthermore, shape and size of the metal phosphide product can be influenced by the shape and size of the metal precursor, allowing for the templated-design of nanostructured metal phosphides. The utility of this technique is not limited to the nano-regime. Bulk-scale metal powders, wires, foils, thin films and nanostructured metals can be converted to metal phosphides using analogous reactions with hot TOP. The two-fold purpose of this work is to extend these solution-mediated nanocrystal-based synthetic strategies to new classes of materials, and to compliment the existing library of low-temperature methods for making solid state materials.

Henkes, Amanda Erin

2008-05-01T23:59:59.000Z

143

Properties and Characterization of Nano-Structured Metal Oxides ...  

Science Conference Proceedings (OSTI)

The objective of this study was to synthesize numerous metal oxide nano- structures including TiO2, Nb-doped TiO2, SnO2, ZnO, and NiO and deposit these ...

144

Displacement method and apparatus for reducing passivated metal powders and metal oxides  

DOE Patents (OSTI)

A method of reducing target metal oxides and passivated metals to their metallic state. A reduction reaction is used, often combined with a flux agent to enhance separation of the reaction products. Thermal energy in the form of conventional furnace, infrared, or microwave heating may be applied in combination with the reduction reaction.

Morrell; Jonathan S. (Knoxville, TN), Ripley; Edward B. (Knoxville, TN)

2009-05-05T23:59:59.000Z

145

Catalytic graphitization of carbon aerogels by transition metals  

Science Conference Proceedings (OSTI)

Carbon aerogels and Cr-, Fe-, Co-, and Ni-containing carbon aerogels were obtained by pyrolysis, at temperatures between 500 and 1,800 C, of the corresponding aerogels prepared by the sol-gel method from polymerization of resorcinol with formaldehyde. All samples were characterized by mercury porosimetry, nitrogen adsorption, X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), and Raman spectroscopy. Results obtained show that carbon aerogels are, essentially, macroporous materials that maintain large pore volumes even after pyrolysis at 1,800 C. For pyrolysis at temperatures higher than 1,000 C, the presence of the transition metals produced graphitized areas with three-dimensional stacking order, as shown by HRTEM, XRD, and Raman spectroscopy. HRTEM also showed that the metal-carbon containing aerogels were formed by polyhedral structures. Cr and Fe seem to be the best catalysts for graphitization of carbon aerogels.

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

2000-05-02T23:59:59.000Z

146

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

147

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.

Schmidt, Frederick A. (Ames, IA); Peterson, David T. (Ames, IA); Wheelock, John T. (Nevada, IA); Jones, Lawrence L. (Des Moines, IA); Lincoln, Lanny P. (Woodward, IA)

1992-02-11T23:59:59.000Z

148

Direct probe of Mott-Hubbard to charge-transfer insulator transition and electronic structure evolution in transition-metal systems  

DOE Green Energy (OSTI)

We report the most direct experimental verification of Mott-Hubbard and charge-transfer insulators through x-ray emission spectroscopy in transition-metal (TM) fluorides. The p-d hybridization features in the spectra allow a straightforward energy alignment of the anion-2p and metal-3d valence states, which visually shows the difference between the two types of insulators. Furthermore, in parallel with the theoretical Zaanen-Sawatzky-Allen diagram, a complete experimental systematics of the 3d Coulomb interaction and the 2p-3d charge-transfer energy is reported and could serve as a universal experimental trend for other TM systems including oxides.

Olalde-Velasco, P; Jimenez-Mier, J; Denlinger, JD; Hussain, Z; Yang, WL

2011-07-11T23:59:59.000Z

149

Interactions of Hydrogen Isotopes and Oxides with Metal Tubes  

DOE Green Energy (OSTI)

Understanding and accounting for interaction of hydrogen isotopes and their oxides with metal surfaces is important for persons working with tritium systems. Reported data from several investigators have shown that the processes of oxidation, adsorption, absorption, and permeation are all coupled and interactive. A computer model has been developed for predicting the interaction of hydrogen isotopes and their corresponding oxides in a flowing carrier gas stream with the walls of a metallic tube, particularly at low hydrogen concentrations. An experiment has been constructed to validate the predictive model. Predictions from modeling lead to unexpected experiment results.

Glen R. Longhurst

2008-08-01T23:59:59.000Z

150

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, and as having a crystalline orientation defined as predominantly C-axis oriented by x-ray diffraction is disclosed.

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

1990-04-16T23:59:59.000Z

151

Internal zone growth method for producing metal oxide metal eutectic composites  

DOE Patents (OSTI)

An improved method for preparing a cermet comprises preparing a compact having about 85 to 95 percent theoretical density from a mixture of metal and metal oxide powders from a system containing a eutectic composition, and inductively heating the compact in a radiofrequency field to cause the formation of an internal molten zone. The metal oxide particles in the powder mixture are effectively sized relative to the metal particles to permit direct inductive heating of the compact by radiofrequency from room temperature. Surface melting is prevented by external cooling or by effectively sizing the particles in the powder mixture.

Clark, Grady W. (Oak Ridge, TN); Holder, John D. (Knoxville, TN); Pasto, Arvid E. (Oak Ridge, TN)

1980-01-01T23:59:59.000Z

152

Methods of making metal oxide nanostructures and methods of controlling morphology of same  

DOE Patents (OSTI)

The present invention includes a method of producing a crystalline metal oxide nanostructure. The method comprises providing a metal salt solution and providing a basic solution; placing a porous membrane between the metal salt solution and the basic solution, wherein metal cations of the metal salt solution and hydroxide ions of the basic solution react, thereby producing a crystalline metal oxide nanostructure.

Wong, Stanislaus S; Hongjun, Zhou

2012-11-27T23:59:59.000Z

153

Ethanol oxidation on metal oxide-supported platinum catalysts  

SciTech Connect

Ethanol is a renewable fuel that can be used as an additive to gasoline (or its substitute) with the advantage of octane enhancement and reduced carbon monoxide exhaust emissions. However, on Ethanol is a renewable fuel that can be used as an additive to gasoline (or its substitute) with the advantage of octane enhancement and reduced carbon monoxide exhaust emissions. However, on the standard three-way catalysts, the conversion of unburned ethanol is low because both ethanol and some of its partially oxidized derivatives are highly resistant to oxidation. A combination of first-principles density-functional theory (DFT) based calculations and in-situ diffuse reflectance infrared spectroscopy (DRIFTS) analysis was applied to uncover some of the fundamental phenomena associated with ethanol oxidation on Pt containing catalysts. In particular, the objective was to analyze the role of the oxide (i.e., ?-Al2O3 or SiO2) substrate on the ethanol oxidation activity. The results showed that Pt nanoparticles trap and accumulate oxygen at their surface and perimeter sites and play the role of “stoves” that burn ethanol molecules and their partially oxidized derivatives to the “final” products. The ?-Al2O3 surfaces provided higher mobility of the fragments of ethanol molecules than the SiO2 surface and hence increased the supply rate of these objects to the Pt particles. This will in turn produce a higher conversion rate of unburned ethanol.and some of its partially oxidized derivatives are highly resistant to oxidation. A combination of first-principles density-functional theory (DFT) based calculations and in-situ diffuse reflectance infrared spectroscopy (DRIFTS) analysis was applied to uncover some of the fundamental phenomena associated with ethanol oxidation on Pt containing catalysts. In particular, the objective was to analyze the role of the oxide (i.e., ?-Al2O3 or SiO2) substrate on the ethanol oxidation activity. The results showed that Pt nanoparticles trap and accumulate oxygen at their surface and perimeter sites and play the role of “stoves” that burn ethanol molecules and their partially oxidized derivatives to the “final” products. The ?-Al2O3 surfaces provided higher mobility of the fragments of ethanol molecules than the SiO2 surface and hence increased the supply rate of these objects to the Pt particles. This will in turn produce a higher conversion rate of unburned ethanol.

L. M. Petkovic 090468; Sergey N. Rashkeev; D. M. Ginosar

2009-09-01T23:59:59.000Z

154

An experimental study of isobutane oxidation at transition temperatures  

SciTech Connect

The oxidation of isobutane at temperatures in the range 563-693 K has been studied experimentally using a static reactor. Gas chromatographic analysis was used to measure stable species concentrations. The experimental results were used to postulate the main reaction paths of the mechanism at these temperatures. A region of negative temperature coefficient (NTC) was observed between 650 and 680 K. Changes in the product yields and product distribution indicated a transition in the mechanism across the NTC region, from low to intermediate temperatures. Analysis of the experimental results and comparison with results for other fuels, such as n-butane, propane and propene, indicated that the NTC and mechanism transition were strongly dependent on the shift in the equilibrium of CH/sub 3/ + O/sub 2/ <==> CH/sub 3/O/sub 2/. The results are also discussed in relation in relation to recent engine results.

Wilk, R.D.; Cernansky, N.P.; Miller, D.L.

1986-01-01T23:59:59.000Z

155

PAD: Polymer-Assisted Deposition of Metal-Oxide and Metal ...  

Wind Energy; Partners (27) Visual Patent ... for the successful production of both simple and complex metal-oxide films such as TiO2, ITO, SrTiO3, TiN, AlN, and ...

156

Initial stages of high temperature metal oxidation  

Science Conference Proceedings (OSTI)

The application of XPS and UPS to the study of the initial stages of high temperature (> 350/sup 0/C) electrochemical oxidation of iron and nickel is discussed. In the high temperature experiments, iron and nickel electrodes were electrochemically oxidized in contact with a solid oxide electrolyte in the uhv system. The great advantages of this technique are that the oxygen activity at the interface may be precisely controlled and the ability to run the reactions in uhv allows the simultaneous observation of the reactions by XPS.

Yang, C.Y.; O'Grady, W.E.

1981-01-01T23:59:59.000Z

157

Strong Bond Activation with Late Transition-Metal Pincer Complexes as a Foundation for Potential Catalysis  

E-Print Network (OSTI)

Strong bond activation mediated by pincer ligated transiton-metal complexes has been the subject of intense study in recent years, due to its potential involvement in catalytic transformations. This dissertation has focused on the net heterolytic cleavage of B-H and B-B bonds across the N-Pd bond in a cationic (PNP)Pd fragment, the C-H oxidative addition to a (PNP)Ir center and the recent results on the C-H and C-O oxidative addition in reactions of aryl carboxylates with the (PNP)Rh fragment. Transition metal carbene and carbyne complexes are of great interest because of their role in a wide variety of catalytic reactions. Our work has resulted in the isolation of a rhodium(I) difluorocarbene. Reaction of the rhodium difluorocarbene complex with a silylium salt led to the C-F bond cleavage and the formation of a terminal fluorocarbyne complex. Reductive elimination is a critical step of cross coupling reactions. In order to examine the effect of the pincer ligand on the reductive elimination reactions from Rh(III), the first pi-accepting PNP ligand bearing pyrrolyl substituents was prepared and installed onto the rhodium center. Arylhalide (halide = Br, I) oxidative addition was achieved in the presence of donor ligands such as acetonitrile to form stable six-coordinate Rh(III) compounds. The C-O reductive elimination reactions in this system were also explored.

Zhu, Yanjun

2012-05-01T23:59:59.000Z

158

A Phenomenological Study of the Metal-Oxide Interface: The Role of Catalysis in Hydrogen Production from Renewable Resources  

SciTech Connect

The truth about Cats: The metal-oxide interface of a Pd-Rh/CeO{sub 2} catalyst was studied in the context of developing active, selective and durable solid catalytic materials for the production of hydrogen from renewables. The presence of a stable contact between finely dispersed transition-metal clusters (Pd and Rh) on the nanoparticles of the CeO{sub 2} support leads to a highly active and stable catalyst for the steam reforming of ethanol.

Idriss, H.; Llorca, J; Chan, S; Blackford, M; Pas, S; Hill, A; Alamgir, F; Rettew, R; Petersburg, C; Barteau, M

2008-01-01T23:59:59.000Z

159

Surfactant-Modified Diffusion on Transition-Metal Surfaces  

DOE Green Energy (OSTI)

Wanting to convert surface impurities from a nuisance to a systematically applicable nano-fabrication tool, we have sought to understand how such impurities affect self-diffusion on transition-metal surfaces. Our field-ion microscope experiments reveal that in the presence of surface hydrogen, self-diffusion on Rh(100) is promoted, while on Pt(100), not only is it inhibited, but its mechanism changes. First-principles calculations aimed at learning how oxygen fosters perfect layerwise growth on a growing Pt(111) crystal contradict the idea in the literature that it does so by directly promoting transport over Pt island boundaries. The discovery that its real effect is to burn off adventitious adsorbed carbon monoxide demonstrates the predictive value of state-of-the-art calculation methods.

FEIBELMAN,PETER J.; KELLOGG,GARY LEE

1999-12-01T23:59:59.000Z

160

SOME AB$sub 3$ COMPOUNDS OF THE TRANSITION METALS  

SciTech Connect

Crystal structure data for fifteen AB/sub 3/ compounds of the transition metals were studied. The alloys were made by arc melting 3 to 5 of the elements in a water-cooled copper crucible. AB/sub 3/ compounds with the Cu/sub 3/Au- structure, Ll/sub 2/, space group Pm/sub 3/m included: ScRh/sub 3/, ScPd/sub 3/, ScPt/sub 3/, YPd/sub 3/, YPt/sub 3/, LaPd/sub 3/, HoPd/sub 3/, HoPt/sub 3/, ThRh/ sub 3/, URh/sub 3/, and Ulr/sub 3/. AB /sub 3/ compounds with close-packed ordered structures included ThPd/sub 3/, VPd/sub 3/, VPt/sub 3/, and HfAl/sub 3/. (M.C.G.)

Dwight, A.E.; Downey, J.W.; Conner, R.A. Jr.

1961-01-10T23:59:59.000Z

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

Flame Synthesis of One-Dimensional Metal Oxide Nanomaterials  

NLE Websites -- All DOE Office Websites (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

162

OXIDATION BEHAVIOR OF WELDED AND BASE METAL UNS N06025  

Science Conference Proceedings (OSTI)

The oxidation behavior of specimens containing tungsten inert gas welds of UNS N06025 (NiCrFeAlY) was investigated in air for up to 5,000h at 900 -1000 C and 1,000h at 1100 -1200 C. In general, the microstructure was very homogeneous in the weld with smaller carbides and the Al2O3 penetrations were similar or smaller compared to those formed in the base metal. Above 1000 C, significant spallation was observed and Al and Cr depletion in the metal was observed to a similar extent in the weld and base metal. The maximum internal oxidation depth of the base metal at 900 and 1100 C was lower than several other commercial Ni-base alloys.

Pint, Bruce A [ORNL; Paul, Larry D. [Thyssen-Krupp VDM

2007-01-01T23:59:59.000Z

163

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

DOE Green Energy (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

164

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

165

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

166

Carbon monoxide oxidation over three different states of copper: Development of a model metal oxide catalyst  

SciTech Connect

Carbon monoxide oxidation was performed over the three different oxidation states of copper -- metallic (Cu), copper (I) oxide (Cu{sub 2}O), and copper (II) oxide (CuO) as a test case for developing a model metal oxide catalyst amenable to study by the methods of modern surface science and catalysis. Copper was deposited and oxidized on oxidized supports of aluminum, silicon, molybdenum, tantalum, stainless steel, and iron as well as on graphite. The catalytic activity was found to decrease with increasing oxidation state (Cu > Cu{sub 2}O > CuO) and the activation energy increased with increasing oxidation state (Cu, 9 kcal/mol < Cu{sub 2}O, 14 kcal/mol < CuO, 17 kcal/mol). Reaction mechanisms were determined for the different oxidation states. Lastly, NO reduction by CO was studied. A Cu and CuO catalyst were exposed to an equal mixture of CO and NO at 300--350 C to observe the production of N{sub 2} and CO{sub 2}. At the end of each reaction, the catalyst was found to be Cu{sub 2}O. There is a need to study the kinetics of this reaction over the different oxidation states of copper.

Jernigan, G.G. [California Univ., Berkeley, CA (United States). Dept. of Chemistry]|[Lawrence Berkeley Lab., CA (United States). Materials and Chemical Sciences Div.

1994-10-01T23:59:59.000Z

167

Measurement system for metal-oxide gas sensors  

Science Conference Proceedings (OSTI)

A study on smell sensing and classification has been developed for a long time by many ways. Most of these have been focused on bad smells, when factors of bad smells were known chemically. Many gas sensors have been developed to detect specific chemicals. ... Keywords: Metal-oxide gas sensor, Multi-channel sensors, Smell measurement

Hideo Araki; Sigeru Omatu

2013-02-01T23:59:59.000Z

168

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

169

SP-29: Oxidation Behavior of Zr56Al16Co28 Metallic Glasses  

Science Conference Proceedings (OSTI)

Abstract Scope, The oxidation behavior of Zr56A16Co28 bulk metallic glass was ... A high resistance against oxidation in Zr56Al16Co28 bulk metallic glasses ...

170

Production of Oxygen Gas and Liquid Metal by Electrochemical Decomposition of Molten Iron Oxide  

E-Print Network (OSTI)

Molten oxide electrolysis (MOE) is the electrolytic decomposition of a metal oxide, most preferably into liquid metal and oxygen gas. The successful deployment of MOE hinges upon the existence of an inert anode capable of ...

Wang, Dihua

171

Viscoelastic properties of oxide-coated liquid metals  

E-Print Network (OSTI)

Many liquid metals exposed to air develop an oxide film on their outer surface. This film is sufficiently solid-like to provide mechanical stability to small liquid metal droplets, yet weak enough to allow the droplets to be malleable. These properties are useful in both micro-electronics and microfluidics; however, little is known about how to characterize them. Here we probe the elastic, yielding, and relaxation properties of oxide-coated gallium and eutectic gallium indium using a rheometer equipped with a parallel-plate geometry. By using parallel plates of different size, we show that surface stresses dominate bulk stresses. These experiments also demonstrate that the apparent elastic properties of the oxide film are highly sensitive to its strain history. Moreover, the apparent elasticity is sensitive to the stresses stored in the oxide skin. We probe these stresses and their time-dependence, with both torque and normal force measurements. We also characterize the time-dependence of the elasticity by observing free vibrations of the rheometer. We rationalize the strain history and time-dependence in terms of oxidation and show that despite this dependence, reproducible elasticity measurements can be obtained due to the ability of shear to produce a state that is independent of the strain history. © 2009 The Society of Rheology. ?DOI: 10.1122/1.3236517? I.

Ryan J. Larsen A; Michael D. Dickey B; George M. Whitesides; David A. Weitz C

2009-01-01T23:59:59.000Z

172

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

173

For cermet inert anode containing oxide and metal phases useful for the electrolytic production of metals  

DOE Patents (OSTI)

A cermet inert anode for the electrolytic production of metals such as aluminum is disclosed. The inert anode comprises a ceramic phase including an oxide of Ni, Fe and M, where M is at least one metal selected from Zn, Co, Al, Li, Cu, Ti, V, Cr, Zr, Nb, Ta, W, Mo, Hf and rare earths, preferably Zn and/or Co. Preferred ceramic compositions comprise Fe.sub.2 O.sub.3, NiO and ZnO or CoO. The cermet inert anode also comprises a metal phase such as Cu, Ag, Pd, Pt, Au, Rh, Ru, Ir and/or Os. A preferred metal phase comprises Cu and Ag. The cermet inert anodes may be used in electrolytic reduction cells for the production of commercial purity aluminum as well as other metals.

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

2002-01-01T23:59:59.000Z

174

Properties of molecular beam epitaxy grown Eu{sub x}(transition metal){sub y} films (transition metals: Mn, Cr)  

Science Conference Proceedings (OSTI)

The electronic and crystallographic structures, as well as the magnetic properties, of Eu{sub x}(transition metal){sub y} (transition metals: Mn, Cr) thin films grown by molecular beam epitaxy were studied. Relative changes of the Eu/Mn and Eu/Cr ratios derived from the XPS lines, as well as x-ray reflectivity, indicate mixing of the Eu/Mn and Eu/Cr layers. Valency transitions from Eu{sup 2+} to Eu{sup 3+} were observed in both systems for most studied stoichiometries. A transition to a magnetically ordered phase was observed at 15 K, 40 K, and 62 K for selected films in the Eu-Mn system, and at 50 K for the film with a Eu/Cr ratio of 0.5.

Balin, K. [A. Chelkowski Institute of Physics, University of Silesia, Katowice, 40-007 (Poland); Center for Magnetism and Magnetic Nanostructures, University of Colorado at Colorado Springs, Colorado Springs, Colorado 80918 (United States); Nowak, A. [A. Chelkowski Institute of Physics, University of Silesia, Katowice, 40-007 (Poland); Laboratoire de Physique de l'Etat Condense, University du Maine, Le Mans Cedex, 72085 (France); Gibaud, A. [Laboratoire de Physique de l'Etat Condense, University du Maine, Le Mans Cedex, 72085 (France); Szade, J. [A. Chelkowski Institute of Physics, University of Silesia, Katowice, 40-007 (Poland); Celinski, Z. [Center for Magnetism and Magnetic Nanostructures, University of Colorado at Colorado Springs, Colorado Springs, Colorado 80918 (United States)

2011-04-01T23:59:59.000Z

175

Dual-environment effects on the oxidation of metallic interconnects  

DOE Green Energy (OSTI)

Metallic interconnects in solid oxide fuel cells are exposed to a dual environment: fuel on one side (i.e., H2 gas) and oxidizer on the other side (i.e., air). It has been observed that the oxidation behavior of thin stainless steel sheet in air is changed by the presence of H2 on the other side of the sheet. The resulting dual-environment scales are flaky and more friable than the single-environment scales. The H2 disrupts the scale on the air side. A model to explain some of the effects of a dual environment is presented where hydrogen diffusing through the stainless steel sheet reacts with oxygen diffusing through the scale to form water vapor, which has sufficient vapor pressure to mechanically disrupt the scale. Experiments on preoxidized 316L stainless steel tubing exposed to air-air, H2-air, and H2-Ar environments are reported in support of the model.

Holcomb, G.R.; Ziomek-Moroz, M.; Covino, B.S., Jr.; Bullard, S.J.

2006-08-01T23:59:59.000Z

176

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

177

Thermodynamic properties of some metal oxide-zirconia systems  

SciTech Connect

Metal oxide-zirconia systems are a potential class of materials for use as structural materials at temperatures above 1900 K. These materials must have no destructive phase changes and low vapor pressures. Both alkaline earth oxide (MgO, CaO, SrO, and BaO)-zirconia and some rare earth oxide (Y2O3, Sc2O3, La2O3, CeO2, Sm2O3, Gd2O3, Yb2O3, Dy2O3, Ho2O3, and Er2O3)-zirconia system are examined. For each system, the phase diagram is discussed and the vapor pressure for each vapor species is calculated via a free energy minimization procedure. The available thermodynamic literature on each system is also surveyed. Some of the systems look promising for high temperature structural materials.

Jacobson, N.S.

1989-12-01T23:59:59.000Z

178

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

179

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

NLE Websites -- All DOE Office Websites (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

180

Metal-Semiconductor Transitions in Nanoscale Vanadium Dioxide - Thin Films, Subwavelength Holes, and Nanoparticles.  

E-Print Network (OSTI)

??Large-volume (bulk) vanadium dioxide (VO2) is an unusual material that undergoes a critical transition from insulating-like to metal-like when the temperature is raised above approximately… (more)

Donev, Eugenii U.

2008-01-01T23:59:59.000Z

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

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

182

Pressure-Induced Phase Transitions in Metallic Glasses  

Science Conference Proceedings (OSTI)

... research activities in several directional substances, e.g., ice, silicon, silica, and ... In this talk, we review recent progress of phase transitions in Ce-

183

Atomic Structure and its Change during Glass Transition of Metallic ...  

Science Conference Proceedings (OSTI)

In addition, we will discuss how the atomic structure evolves during glass transition ... Age Hardening of 7075 Alloy Processed by High-pressure Sliding ( HPS).

184

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

185

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

186

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

187

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

NLE Websites -- All DOE Office Websites (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.

188

Tuning of the Metal-Insulator Transition via Alkali Adsorption  

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

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,...

189

Sintering Performance of YSZ Ceramics with Transition Metal Oxide ...  

Science Conference Proceedings (OSTI)

Density Functional Theory Study of Grain Boundary Properties in Ni-Base ... Development of Friction Stir Welding Technology for Coal and Nuclear Power ... Low Cost Aqueous Electrolyte Based Energy Storage: Materials and Performance.

190

SYNTHESIZING THIN FILMS OF LITHIATED TRANSITION METAL OXIDE ...  

Biomass and Biofuels; Building Energy Efficiency; ... (140) a source material (322) within a deposition chamber (310) such as a target for sputtering, and the ...

191

Transition Metal Doping of Manganese Cobalt Spinel Oxides for ...  

Science Conference Proceedings (OSTI)

... Nanoparticle Catalysts for Hydrogen Production from Methanol and Methane ... of Long Term Aging on Creep Properties of HP Alloy Hydrogen Reformer Tubes ... of Traditionally Wrought Ni-Based Superalloys for USC Steam Turbines.

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

One-Dimensional Nanostructures of Transition Metal Oxides with ...  

Science Conference Proceedings (OSTI)

Approaching Multimaterial 3D Nanostructured Gas Phase Nanoxerographic Printers · Carbon Nanotube Coatings Laser Power and Energy Measurements.

194

Nanosized Transition Metal Oxides for Energy Storage Applications  

Science Conference Proceedings (OSTI)

Chemical Synthesis and Structural Analysis of Gd2O3 Nanoparticles for Optical Applications · Complex Crystallization Dynamics in Amorphous Germanium ...

195

Work function control at metal high-dielectric-constant gate oxide interfaces  

Science Conference Proceedings (OSTI)

There has been difficulty in finding metals of sufficiently large or small effective work function to act as metal electrodes on high-dielectric-constant gate oxides. To understand the factors affecting the effective work function, we have calculated ... Keywords: High K oxides, Metal gates

K. Tse; J. Robertson

2008-01-01T23:59:59.000Z

196

Theory of quantum metal to superconductor transitions in highly conducting systems  

SciTech Connect

We derive the theory of the quantum (zero temperature) superconductor to metal transition in disordered materials when the resistance of the normal metal near criticality is small compared to the quantum of resistivity. This can occur most readily in situations in which 'Anderson's theorem' does not apply. We explicitly study the transition in superconductor-metal composites, in an swave superconducting film in the presence of a magnetic field, and in a low temperature disordered d-wave superconductor. Near the point of the transition, the distribution of the superconducting order parameter is highly inhomogeneous. To describe this situation we employ a procedure which is similar to that introduced by Mott for description of the temperature dependence of the variable range hopping conduction. As the system approaches the point of the transition from the metal to the superconductor, the conductivity of the system diverges, and the Wiedemann-Franz law is violated. In the case of d-wave (or other exotic) superconductors we predict the existence of (at least) two sequential transitions as a function of increasing disorder: a d-wave to s-wave, and then an s-wave to metal transition.

Spivak, B.

2010-04-06T23:59:59.000Z

197

Femtosecond NEXAFS of Photoinduced Insulator-Metal Transition in VO2  

NLE Websites -- All DOE Office Websites (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).

198

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

199

Giant magnetoresistance in oxide-based metallic multilayers  

Science Conference Proceedings (OSTI)

The authors report on the first measurement of low-field giant magnetoresistance in metallic multilayers of perovskite oxides. The authors performed in-plane measurements of the magnetoelectric transport properties in La{sub 0.75}Sr{sub 0.25}MnO{sub 3}/LaNiO{sub 3} trilayers and succeeded in distinguishing the giant magnetoresistance effect from other contributions to the total magnetoresistance. The samples were grown on single-crystalline SrTiO{sub 3} substrates by dc sputtering.

Granada, Mara; Rojas Sanchez, J. Carlos; Steren, Laura B. [Centro Atomico Bariloche and Instituto Balseiro, Comision Nacional de Energia Atomica (R8402AGP) San Carlos de Bariloche, Rio Negro (Argentina)

2007-08-13T23:59:59.000Z

200

Neutral bimetallic transition metal phenoxyiminato catalysts and related polymerization methods  

SciTech Connect

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

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

2012-08-07T23:59:59.000Z

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

Acoustic plane wave preferential orientation of metal oxide superconducting materials  

DOE Patents (OSTI)

A polycrystalline metal oxide such as YBa.sub.2 Cu.sub.3 O.sub.7-X (where 0metal oxide in the form of a ceramic slip which has not yet set, orientation of the crystal basal planes parallel with the direction of desired current flow is accomplished by an applied acoustic plane wave in the acoustic or ultrasonic frequency range (either progressive or standing) in applying a torque to each crystal particle. The ceramic slip is then set and fired by conventional methods to produce a conductor with preferentially oriented grains and substantially enhanced current carrying capacity.

Tolt, Thomas L. (North Olmsted, OH); Poeppel, Roger B. (Glen Ellyn, IL)

1991-01-01T23:59:59.000Z

202

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

DOE Green Energy (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

203

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. 1 fig.

Isenberg, A.O.

1987-03-10T23:59:59.000Z

204

Metal-based turn-on fluorescent probes for nitric oxide sensing  

E-Print Network (OSTI)

Chapter 1. Metal-Based Turn-On Fluorescent Probes for Sensing Nitric Oxide. Nitric oxide, a reactive free radical, regulates a variety of biological processes. The absence of tools to detect NO directly, rapidly, specifically ...

Lim, Mi Hee

2006-01-01T23:59:59.000Z

205

Investigation of the nature of electronic states in the alkali_metal oxides  

Science Conference Proceedings (OSTI)

Hartree-Fock and Density functional theories have been applied to investigate the density of electronic states and electronic band structures. We studied: oxides, peroxides, nadoxides and ozonides, alkali-metal oxides M2O, peroxides M2O2, ...

O. O. Obolonskaya

2010-05-01T23:59:59.000Z

206

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.

207

Oxidation Resistance of Zr- and Ti- Based Bulk Metallic Glasses in ...  

Science Conference Proceedings (OSTI)

About this Abstract. Meeting, 2012 TMS Annual Meeting & Exhibition. Symposium , Bulk Metallic Glasses IX. Presentation Title, Oxidation Resistance of Zr- and ...

208

The use of natural gas for reduction of metal oxides: constraints and ...  

Science Conference Proceedings (OSTI)

Presentation Title, The use of natural gas for reduction of metal oxides: constraints ... Reaction mechanism and reaction rate of Sn evaporation from liquid steel.

209

Theory of a Continuous Stripe Melting Transition in a Two-Dimensional Metal: A Possible Application to Cuprate Superconductors  

E-Print Network (OSTI)

We construct a theory of continuous stripe melting quantum phase transitions in two-dimensional metals and the associated Fermi surface reconstruction. Such phase transitions are strongly coupled but yet theoretically ...

Mross, David Fabian

210

Dual Environment Effects on the Oxidation of Metallic Interconnects  

DOE Green Energy (OSTI)

Metallic interconnects in solid oxide fuel cells are exposed to a dual environment: fuel on one side (i.e. H2 gas) and oxidizer on the other side (i.e. air). It has been observed that the oxidation behavior of thin stainless steel sheet in air is changed by the presence of H2 on the other side of the sheet. The resulting dual environment scales are flaky and more friable than the single environment scales. The H2 disrupts the scale on the air-side. A model to explain some of the effects of a dual environment is presented where hydrogen diffusing through the stainless steel sheet reacts with oxygen diffusing through the scale to form water vapor, which has sufficient vapor pressure to mechanically disrupt the scale. Experiments on preoxidized 316L stainless steel tubing exposed to air/air, H2/air, and H2/Ar environments are reported in support of the model.

Holcomb, Gordon R.; Ziomek-Moroz, Malgorzata; Cramer, Stephen D.; Covino, Jr., Bernard S.; and Bullard, Sophie J.

2004-10-20T23:59:59.000Z

211

Transition metal catalysis in the generation of petroleum and natural gas. Progress report, [1992--1993  

DOE Green Energy (OSTI)

A new hypothesis is introduced for the generation of petroleum and natural gas. The transition metals, activated under the reducing conditions of diagenesis, are proposed as catalysts in the generation of light hydrocarbons. The objective of this proposal is to test that hypothesis. Transition metals (Ni, V, Ti, Co, Fe), in kerogen, porphyrins, and as pure compounds, will be tested under catagenic conditions for catalytic activity in the conversion of normal paraffins and hydrogen into light hydrocarbons. If the hypothesis is correct, kerogenous transition metals should become catalytically active under the reducing conditions of diagenesis and catalyze the conversion of paraffins into the light hydrocarbons seen in petroleum. Moreover, the C{sub 1}-C{sub 4} hydrocarbons generated catalytically should be similar in molecular and isotopic compositions to natural gas.

Mango, F.

1993-08-01T23:59:59.000Z

212

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

213

Surface Oxidation and Dissolution of Metal Nanocatalysts in Acid Medium  

E-Print Network (OSTI)

One of the most important challenges in low-temperature fuel cell technology is improving the catalytic efficiency at the electrode-catalyst where the oxygen reduction reaction (ORR) occurs. Platinum is the best pure catalyst for this reaction but its high cost and scarcity hinder the commercial implementation of fuel cells in automobiles. Pt-based alloys are promising alternatives to substitute platinum while maintaining the efficiency and life-time of the pure catalyst. However, the acid medium and the oxidation of the surface reduce the activity and durability of the alloy catalyst through changes in its local composition and structure. Molecular simulation techniques are applied to characterize the thermodynamics and dynamic evolution of the surface of platinum-based alloy catalysts under reaction conditions.1-10 A simulation scheme of the surface oxidation is proposed which combines classical molecular dynamics (MD) and density functional theory (DFT). This approach is able to reproduce the main features of the oxidation phenomena observed experimentally, it is concluded that the dissolution mechanism of metal atoms involves: 1) Surface segregation of alloy atoms, 2) oxygen absorption into the subsurface of the catalyst, and 3) metal detachment through the interaction with ions in the solvent. Therefore, to improve the durability of platinum-based alloy catalysts, the steps of the dissolution mechanism must be prevented. A versatile 3-D kinetic Monte Carlo (KMC) code is developed to study the degradation and dealloying in nanocatalysts. The results on the degradation of Pt nanoparticles under different potential regimes demonstrate that the dissolution depends on the potential path to which the nanocatalyst is exposed. Metal atoms detach from the boundaries of (111) facets expecting a reduction in the activity of the nanoparticle. Also, the formation of Pt hollow nanoparticles by the Kirkendall effect is addressed, the role of vacancies is crucial in the removal of the non-noble core that yields to hollow nanoparticles. To investigate the reasons for the experimentally found enhanced ORR activity in porous/hollow nanoparticles, the effect of subsurface vacancies on the main ORR activity descriptors is studied with DFT. It is found that an optimum amount of vacancies may enhance the ORR activity of Pt-monolayer catalysts over certain alloy cores by changing the binding energies of O and OH.

Callejas-Tovar, Juan

2012-08-01T23:59:59.000Z

214

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

Science Conference Proceedings (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

215

Femtosecond NEXAFS of Photoinduced Insulator-Metal Transition in VO2  

NLE Websites -- All DOE Office Websites (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.

216

Femtosecond NEXAFS of Photoinduced Insulator-Metal Transition in VO2  

NLE Websites -- All DOE Office Websites (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.

217

Femtosecond NEXAFS of Photoinduced Insulator-Metal Transition in VO2  

NLE Websites -- All DOE Office Websites (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.

218

Femtosecond NEXAFS of Photoinduced Insulator-Metal Transition in VO2  

NLE Websites -- All DOE Office Websites (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.

219

Solar Thermal Electrolytic Production of Metals from Their Oxides  

Science Conference Proceedings (OSTI)

Symposium, Alternative Energy Resources for Metals and Materials Production Symposium. Presentation Title, Solar Thermal Electrolytic Production of Metals ...

220

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

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

GaN Metal Oxide Semiconductor Field Effect Transistors  

SciTech Connect

A GaN based depletion mode metal oxide semiconductor field effect transistor (MOSFET) was demonstrated using Ga{sub 2}O{sub 3}(Gd{sub 2}O{sub 3}) as the gate dielectric. The MOS gate reverse breakdown voltage was > 35V which was significantly improved from 17V of Pt Schottky gate on the same material. A maximum extrinsic transconductance of 15 mS/mm was obtained at V{sub ds} = 30 V and device performance was limited by the contact resistance. A unity current gain cut-off frequency, f{sub {tau}}, and maximum frequency of oscillation, f{sub max} of 3.1 and 10.3 GHz, respectively, were measured at V{sub ds} = 25 V and V{sub gs} = {minus}20 V.

Ren, F.; Pearton, S.J.; Abernathy, C.R.; Baca, A.; Cheng, P.; Shul, R.J.; Chu, S.N.G.; Hong, M.; Lothian, J.R.; Schurman, M.J.

1999-03-02T23:59:59.000Z

222

Metal oxide morphology in argon-assisted glancing angle deposition  

Science Conference Proceedings (OSTI)

Glancing angle deposition (GLAD) is a thin film deposition technique capable of fabricating columnar architectures such as posts, helices, and chevrons with control over nanoscale film features. Argon bombardment during deposition modifies the GLAD process, producing films with new morphologies which have shown promise for sensing and photonic devices. The authors report modification of column tilt angle, film density, and specific surface area for 12 different metal oxide and fluoride film materials deposited using Ar-assisted GLAD. For the vapor flux/ion beam geometry and materials studied here, with increasing argon flux, the column tilt increases, film density increases, and specific surface area decreases. With a better understanding of the nature of property modification and the mechanisms responsible, the Ar-assisted deposition process can be more effectively targeted towards specific applications, including birefringent thin films or photonic crystal square spirals.

Sorge, J. B.; Taschuk, M. T.; Wakefield, N. G.; Sit, J. C.; Brett, M. J. [Department of Electrical and Computer Engineering, University of Alberta, Edmonton, AB T6G 2V4 (Canada); Department of Electrical and Computer Engineering, University of Alberta, Edmonton, AB T6G 2V4 (Canada) and NRC National Institute for Nanotechnology, Edmonton, AB T6G 2M9 (Canada)

2012-03-15T23:59:59.000Z

223

Chemical bonding of hydrogen molecules to transition metal complexes  

DOE Green Energy (OSTI)

The complex W(CO){sub 3}(PR{sub 3}){sub 2}(H{sub 2}) (CO = carbonyl; PR{sub 3} = organophosphine) was prepared and was found to be a stable crystalline solid under ambient conditions from which the hydrogen can be reversibly removed in vacuum or under an inert atmosphere. The weakly bonded H{sub 2} exchanges easily with D{sub 2}. This complex represents the first stable compound containing intermolecular interaction of a sigma-bond (H-H) with a metal. The primary interaction is reported to be donation of electron density from the H{sub 2} bonding electron pair to a vacant metal d-orbital. A series of complexes of molybdenum of the type Mo(CO)(H{sub 2})(R{sub 2}PCH{sub 2}CH{sub 2}PR{sub 2}){sub 2} were prepared by varying the organophosphine substitutent to demonstrate that it is possible to bond either dihydrogen or dihydride by adjusting the electron-donating properties of the co-ligands. Results of infrared and NMR spectroscopic studies are reported. 20 refs., 5 fig.

Kubas, G.J.

1990-01-01T23:59:59.000Z

224

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

SciTech Connect

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

225

Method of dissolving metal oxides with di- or polyphosphonic acid and a redundant  

DOE Patents (OSTI)

A method of dissolving metal oxides using a mixture of a di- or polyphosphonic acid and a reductant wherein each is present in a sufficient amount to provide a synergistic effect with respect to the dissolution of metal oxides and optionally containing corrosion inhibitors and pH adjusting agents.

Horwitz, Earl P. (Argonne, IL); Chiarizia, Renato (Argonne, IL)

1996-01-01T23:59:59.000Z

226

HIGH TEMPERATURE OXIDATION/CORROSION BEHAVIOR OF METALS AND ALLOYS UNDER A HYDROGEN GRADIENT  

Science Conference Proceedings (OSTI)

Metallic interconnects in SOFC stacks, perform in challenging environment, as they are simultaneously exposed to a reducing environment (e.g. hydrogen, reformate) on one side and an oxidizing environment (e.g. air) on the other side at elevated temperatures. To understand the oxidation/corrosion behavior of metals and alloys under the dual exposures and assess their suitability, selected metals and alloys, including nickel, Fe-Cr and Ni-Cr base chromia forming alloys, alumina forming Fecralloy®, were investigated. It was found that the oxidation/corrosion behavior of metals and alloys in the presence of dual environment can be significantly different in terms of scale structure and/or chemistry from their exposure in a single oxidizing or reducing atmosphere. The anomalous oxidization/corrosion is attributed to the presence of hydrogen diffusion flux from the fuel side to the air side under the influence of a hydrogen gradient across the metallic substrates.

Yang, Z Gary; Xia, Gordon; Walker, Matthew S.; Wang, Chong M.; Stevenson, Jeffry W.; Singh, Prabhakar

2007-11-01T23:59:59.000Z

227

Thermal battery. [solid metal halide electrolytes with enhanced electrical conductance after a phase transition  

DOE Patents (OSTI)

The patent describes an improved thermal battery whose novel design eliminates various disadvantages of previous such devices. Its major features include a halide cathode, a solid metal halide electrolyte which has a substantially greater electrical conductance after a phase transition at some temperature, and a means for heating its electrochemical cells to activation temperature.

Carlsten, R.W.; Nissen, D.A.

1973-03-06T23:59:59.000Z

228

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

229

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

Science Conference Proceedings (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

230

Transition metal-catalyzed process for addition of amines to carbon-carbon double bonds  

DOE Patents (OSTI)

The present invention is directed to a process for addition of amines to carbon-carbon double bonds in a substrate, comprising: reacting an amine with a compound containing at least one carbon-carbon double bond in the presence a transition metal catalyst under reaction conditions effective to form a product having a covalent bond between the amine and a carbon atom of the former carbon-carbon double bond. The transition metal catalyst comprises a Group 8 metal and a ligand containing one or more 2-electron donor atoms. The present invention is also directed to enantioselective reactions of amine compounds with compounds containing carbon-carbon double bonds, and a calorimetric assay to evaluate potential catalysts in these reactions.

Hartwig, John F. (Durham, CT); Kawatsura, Motoi (Chatham, NJ); Loeber, Oliver (New Haven, CT)

2002-01-01T23:59:59.000Z

231

Rate limiting mechanism of transition metal gettering in multicrystalline silicon  

DOE Green Energy (OSTI)

The authors have performed studies on multicrystalline silicon used for solar cells in the as-grown state and after a series of processing and gettering steps. The principal goal of this work is to determine the rate limiting step for metal impurity gettering from multicrystalline silicon with an emphasis on the release of impurities from structural defects. Synchrotron-based x-ray fluorescence mapping was used to monitor the release process. Copper and nickel impurities were found to reside primarily at dislocations in the as-grown state of the material. Short annealing treatments rapidly dissolved the impurity agglomerates. Based on these results and modeling of the dissolution process, copper and nickel is in the form of small agglomerates (< 10 nm) clustered together over micron-scale regions in the as-grown material. Aluminum gettering further disintegrated the agglomerates to below the sensitivity of the system, 2--5 nm in radii. No significant barrier to release of copper or nickel from dislocations was observed.

McHugo, S.A.; Thompson, A.C. [Lawrence Berkeley National Lab., CA (United States); Imaizumi, M. [Toyota Technological Inst., Nagoya (Japan); Hieslmair, H.; Weberr, E.R. [Univ. of California, Berkeley, CA (United States). Dept. of Materials Science

1997-07-01T23:59:59.000Z

232

Process and apparatus for generating elemental sulfur and re-usable metal oxide from spent metal sulfide sorbents  

DOE Patents (OSTI)

A process and apparatus for generating elemental sulfur and re-usable metal oxide from spent metal-sulfur compound. Spent metal-sulfur compound is regenerated to re-usable metal oxide by moving a bed of spent metal-sulfur compound progressively through a single regeneration vessel having a first and second regeneration stage and a third cooling and purging stage. The regeneration is carried out and elemental sulfur is generated in the first stage by introducing a first gas of sulfur dioxide which contains oxygen at a concentration less than the stoichiometric amount required for complete oxidation of the spent metal-sulfur compound. A second gas containing sulfur dioxide and excess oxygen at a concentration sufficient for complete oxidation of the partially spent metal-sulfur compound, is introduced into the second regeneration stage. Gaseous sulfur formed in the first regeneration stage is removed prior to introducing the second gas into the second regeneration stage. An oxygen-containing gas is introduced into the third cooling and purging stage. Except for the gaseous sulfur removed from the first stage, the combined gases derived from the regeneration stages which are generally rich in sulfur dioxide and lean in oxygen, are removed from the regenerator as an off-gas and recycled as the first and second gas into the regenerator. Oxygen concentration is controlled by adding air, oxygen-enriched air or pure oxygen to the recycled off-gas.

Ayala, Raul E. (Clifton Park, NY); Gal, Eli (Lititz, PA)

1995-01-01T23:59:59.000Z

233

Electronically conductive ceramics for high temperature oxidizing environments  

DOE Patents (OSTI)

This invention pertains to a high temperature, ceramic composition having electronic conductivity as measured by resistivity below about 500 ohm-cm, chemical stability particularly with respect to cathode conditions in a molten carbonate fuel cell, and composed of an alkali metal, transition metal oxide containing a dopant metal in the crystalline structure to replace a portion of the alkali metal or transition metal.

Kucera, G.H.; Smith, J.L.; Sim, J.W.

1983-11-10T23:59:59.000Z

234

Block entanglement of the Gutzwiller state and metal-insulator transition in nanochains  

E-Print Network (OSTI)

The block entanglement entropy is investigated in the Gutzwiller state as a function of the correlation projection parameter. A chain of $N$ sites is partitioned into two equal blocks. The entanglement entropy follows the conformal field theory (CFT) prediction of a logarithmic divergence with the size of the block in both the insulating limit (g=0) with central charge c=1, and the metallic limit (g=1) with c=2. In the metal-insulator crossover regime, it deviates from the CFT result. A scaling form is proposed that gives a good data collapse, exhibiting a metal-insulator crossover at g*N^(1/3) ~ 0.24. The entanglement spectrum also shows noticeable deviation, from the CFT prediction, in the crossover regime, thus it can also track a metal-insulator transition. The spacing distribution of the eigenvalues of the block reduced density matrix is investigated as a function of g, and is seen to exhibit a weak signature of the metal-insulator crossover. These results compare well with recent experiments on metal-insulator transitions in Ni nanochains.

Archak Purkayastha; V. Subrahmanyam

2013-07-06T23:59:59.000Z

235

Chemically Modified Metal Oxide Nanostructure for Photoelectrochemical Water Splitting  

E-Print Network (OSTI)

nanoparticle seeded indium-tin oxide (ITO) substrate usingarrays were grown on an indium-tin oxide substrate followedof a double-sided indium-tin-oxide (ITO) glass substrate

Wang, Gongming

2013-01-01T23:59:59.000Z

236

Method for heat treating and sintering metal oxides with microwave radiation  

DOE Patents (OSTI)

A method for microwave sintering materials, primarily metal oxides, is described. Metal oxides do not normally absorb microwave radiation at temperatures ranging from about room temperature to several hundred degrees centrigrade are sintered with microwave radiation without the use of the heretofore required sintering aids. This sintering is achieved by enclosing a compact of the oxide material in a housing or capsule formed of a oxide which has microwave coupling properties at room temprature up to at least the microwave coupling temperature of the oxide material forming the compact. The heating of the housing effects the initial heating of the oxide material forming the compact by heat transference and then functions as a thermal insulator for the encased oxide material after the oxide material reaches a sufficient temperature to adequately absorb or couple with microwave radiation for heating thereof to sintering temperature.

Holcombe, Cressie E. (Farragut, TN); Dykes, Norman L. (Oak Ridge, TN); Meek, Thomas T. (Knoxville, TN)

1989-01-01T23:59:59.000Z

237

Production of crystalline refractory metal oxides containing colloidal metal precipitates and useful as solar-effective absorbers  

DOE Patents (OSTI)

This invention is a new process for producing refractory crystalline oxides having improved or unusual properties. The process comprises the steps of forming a doped-metal crystal of the oxide; exposing the doped crystal in a bomb to a reducing atmosphere at superatmospheric pressure and a temperature effecting precipitation of the dopant metal in the crystal lattice of the oxide but insufficient to effect net diffusion of the metal out of the lattice; and then cooling the crystal. Preferably, the cooling step is effected by quenching. The process forms colloidal precipitates of the metal in the oxide lattice. The process may be used, for example, to produce thermally stable black MgO crystalline bodies containing magnetic colloidal precipitates consisting of about 99% Ni. The Ni-containing bodies are solar-selective absorbers, having a room-temperature absorptivity of about 0.96 over virtually all of the solar-energy spectrum and exhibiting an absorption edge in the region of 2 .mu.m. The process parameters can be varied to control the average size of the precipitates. The process can produce a black MgO crystalline body containing colloidal Ni precipitates, some of which have the face-centered-cubic structure and others of which have the body-centered cubic structure. The products of the process are metal-precipitate-containing refractory crystalline oxides which have improved or unique optical, mechanical, magnetic, and/or electronic properties.

Narayan, Jagdish (Knoxville, TN); Chen, Yok (Oak Ridge, TN)

1983-01-01T23:59:59.000Z

238

Extrusion of metal oxide superconducting wire, tube or ribbon  

DOE Patents (OSTI)

A process and apparatus for extruding a superconducting metal oxide composition YBa{sub 2}Cu{sub 3}O{sub 7-x} provides a wire (tube or ribbon) having a cohesive mass and a degree of flexibility together with enhanced electrical properties. Wire diameters in the range of 6--85 mils have been produced with smaller wires on the order of 10 mils in diameter exhibiting enhanced flexibility for forming braided, or multistrand, configurations for greater current carrying capacity. The composition for extrusion contains a polymeric binder to provide a cohesive mass to bind the particles together during the extrusion process with the binder subsequently removed at lower temperatures during sintering. The composition for extrusion further includes a deflocculent, an organic plasticizer and a solvent which also are subsequently removed during sintering. Electrically conductive tubing with an inner diameter of 52 mil and an outer diameter of 87--335 mil has also been produced. Flat ribbons have been produced in the range of 10--125 mil thick by 100--500 mil wide. The superconducting wire, tube or ribbon may include an outer ceramic insulating sheath co-extruded with the wire, tubing or ribbon.

Dusek, J.T.

1990-01-01T23:59:59.000Z

239

Protonation enthalpies of metal oxides from high temperature electrophoresis.  

Science Conference Proceedings (OSTI)

Surface protonation reactions play an important role in the behavior of mineral and colloidal systems, specifically in hydrothermal aqueous environments. However, studies addressing the reactions at the solid/liquid interface at temperatures above 100 C are scarce. In this study, newly and previously obtained high temperature electrophoresis data (up to 260 C) - zeta potentials and isoelectric points - for metal oxides, including SiO{sub 2}, SnO{sub 2}, ZrO{sub 2}, TiO{sub 2}, and Fe{sub 3}O{sub 4}, were used in thermodynamic analysis to derive the standard enthalpies of their surface protonation. Two different approaches were used for calculating the protonation enthalpy: one is based on thermodynamic description of the 1-pKa model for surface protonation, and another one - on a combination of crystal chemistry and solvation theories which link the relative permittivity of the solid phase and the ratio of the Pauling bond strength and bond length to standard protonation enthalpy. From this analysis, two expressions relating the protonation enthalpy to the relative permittivity of the solid phase were obtained.

Rodriguez-Santiago, V [Oak Ridge National Laboratory (ORNL); Fedkin, Mark V [ORNL; Lvov, Serguei N. [Pennsylvania State University

2012-01-01T23:59:59.000Z

240

Protonation enthalpies of metal oxides from high temperature electrophoresis  

SciTech Connect

Surface protonation reactions play an important role in the behavior of mineral and colloidal systems, specifically in hydrothermal aqueous environments. However, studies addressing the reactions at the solid/liquid interface at temperatures above 100 C are scarce. In this study, newly and previously obtained high temperature electrophoresis data (up to 260 C) zeta potentials and isoelectric points for metal oxides, including SiO2, SnO2, ZrO2, TiO2, and Fe3O4, were used in thermodynamic analysis to derive the standard enthalpies of their surface protonation. Two different approaches were used for calculating the protonation enthalpy: one is based on thermodynamic description of the 1-pKa model for surface protonation, and another one on a combination of crystal chemistry and solvation theories which link the relative permittivity of the solid phase and the ratio of the Pauling bond strength and bond length to standard protonation enthalpy. From this analysis, two expressions relating the protonation enthalpy to the relative permittivity of the solid phase were obtained.

Rodriguez-Santiago, V [Oak Ridge National Laboratory (ORNL); Fedkin, Mark V. [Pennsylvania State University; Lvov, Serguei N. [Pennsylvania State University

2012-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "transition metal oxides" 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.
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241

Energy ratings for metal oxide varistors under repetitively pulsed operation  

DOE Green Energy (OSTI)

Nonlinear resistors can be used to improve the energy transfer efficiency of inductive energy storage systems that use resistive transfer elements. Improved energy transfer efficiency can result in significant cost savings in some large systems if the cost of the nonlinear resistor is less than the cost of the energy storage and charging hardware that the resistor replaces. This report describes experimental tests that were done to determine appropriate energy ratings for ZnO Metal Oxide Varistors (MOVs) for pulsed conditions from 10 to 20 ms long. Tests were performed first on single MOV units which were forced to failure in a small number of shots. Then several sets of matched pairs were operated under identical conditions to investigate current sharing and the statistics of failure. Test results show that the standard rating method used by manufacturers relating peak current, pulse length, and expected lifetime are adequate, but somewhat conservative. The manufacturers' energy ratings project to a very economical nonlinear transfer resistor. 7 refs., 4 figs., 1 tab.

Melton, J.G.

1989-01-01T23:59:59.000Z

242

Extrusion of metal oxide superconducting wire, tube or ribbon  

DOE Patents (OSTI)

A process for extruding a superconducting metal oxide composition YBa.sub.2 Cu.sub.3 O.sub.7-x provides a wire (tube or ribbon) having a cohesive mass and a degree of flexibility together with enhanced electrical properties. Wire diameters in the range of 6-85 mils have been produced with smaller wires on the order of 10 mils in diameter exhibiting enhanced flexibility for forming braided, or multistrand, configurations for greater current carrying capacity. The composition for extrusion contains a polymeric binder to provide a cohesive mass to bind the particles together during the extrusion process with the binder subsequently removed at lower temperatures during sintering. The composition for extrusion further includes a deflocculent, an organic plasticizer and a solvent which also are subsequently removed during sintering. Electrically conductive tubing with an inner diameter of 52 mil and an outer diameter of 87-355 mil has also been produced. Flat ribbons have been produced in the range of 10-125 mil thick by 100-500 mil wide. The superconducting wire, tube or ribbon may include an outer ceramic insulating sheath co-extruded with the wire, tubing or ribbon.

Dusek, Joseph T. (Lombard, IL)

1993-01-01T23:59:59.000Z

243

METHOD FOR THE PREPARATION OF STABLE ACTINIDE METAL OXIDE-CONTAINING SLURRIES AND OF THE OXIDES THEREFOR  

DOE Patents (OSTI)

This patent deals with a method of preparing actinide metal oxides of a very fine particle size and of forming stable suspensions therefrom. The process consists of dissolving the nitrate of the actinide element in a combustible organic solvent, converting the solution obtained into a spray, and igniting the spray whereby an oxide powder is obtained. The oxide powder is then slurried in an aqueous soiution of a substance which is adsorbable by said oxides, dspersed in a colloid mill whereby a suspension is obtained, and electrodialyzed until a low spectiic conductance is reached.

Hansen, R.S.; Minturn, R.E.

1958-02-25T23:59:59.000Z

244

Hydrogen Adsorption, Absorption and Diffusion on and in Transition Metal Surfaces: A DFT Study  

Science Conference Proceedings (OSTI)

Periodic, self-consistent DFT-GGA(PW91) calculations are used to study the interaction of hydrogen with different facets of seventeen transition metals—the (100) and (111) facets of face-centered cubic (fcc) metals, the (0001) facet of hexagonal-close packed (hcp) metals, and the (100) and (110) facets of body-centered cubic (bcc) metals. Calculated geometries and binding energies for surface and subsurface hydrogen are reported and are, in general, in good agreement with both previous modeling studies and experimental data. There are significant differences between the binding on the close-packed and more open (100) facets of the same metal. Geometries of subsurface hydrogen on different facets of the same metal are generally similar; however, binding energies of hydrogen in the subsurface of the different facets studied showed significant variation. Formation of surface hydrogen is exothermic with respect to gas-phase H? on all metals studied with the exception of Ag and Au. For each metal studied, hydrogen in its preferred subsurface state is always less stable than its preferred surface state. The magnitude of the activation energy for hydrogen diffusion from the surface layer into the first subsurface layer is dominated by the difference in the thermodynamic stability of these two states. Diffusion from the first subsurface layer to one layer further into the bulk does not generally have a large thermodynamic barrier but still has a moderate kinetic barrier. Despite the proximity to the metal surface, the activation energy for hydrogen diffusion from the first to the second subsurface layer is generally similar to experimentally-determined activation energies for bulk diffusion found in the literature. There are also some significant differences in the activation energy for hydrogen diffusion into the bulk through different facets of the same metal.

Ferrin, Peter A.; Kandoi, Shampa; Nilekar, Anand U.; Mavrikakis, Manos

2012-01-04T23:59:59.000Z

245

Structural phase transitions and superconductivity in lanthanum copper oxides  

SciTech Connect

Despite the enormous effort expended over the past ten years to determine the mechanism underlying high temperature superconductivity in cuprates there is still no consensus on the physical origin of this fascinating phenomenon. This is a consequence of a number of factors, among which are the intrinsic difficulties in understanding the strong electron correlations in the copper oxides, determining the roles played by antiferromagnetic interactions and low dimensionality, analyzing the complex phonon dispersion relationships, and characterizing the phase diagrams which are functions of the physical parameters of temperature and pressure, as well as the chemical parameters of stoichiometry and hole concentration. In addition to all of these intrinsic difficulties, extrinsic materials issues such as sample quality and homogeneity present additional complications. Within the field of high temperature superconductivity there exists a subfield centered around the material originally reported to exhibit high temperature superconductivity by Bednorz and Mueller, Ba doped La{sub 2}CuO{sub 4}. This is structurally the simplest cuprate superconductor. The authors report on studies of phase differences observed between such base superconductors doped with Ba or Sr. What these studies have revealed is a fascinating interplay of structural, magnetic and superconducting properties which is unique in the field of high temperature superconductivity and is summarized in this paper.

Crawford, M.K.; Harlow, R.L.; McCarron, E.M. [DuPont, Wilmington, DE (United States)] [and others

1996-12-31T23:59:59.000Z

246

Carrier Localization, Metal-Insulator Transitions and Stripe Formation in Inhomogeneous Hole-Doped Cuprates  

E-Print Network (OSTI)

We propose a unified approach for describing the carrier localization, metal-insulator transitions (MITs) and stripe formation in high-$T_c$ cuprates. The ground-state energy of a carrier interacting with a defect and with lattice vibrations is calculated within the continuum model and adiabatic approximation. At low doping levels, hole carriers in $\\rm{La}$-based systems with large-radius dopants are localized near the dopants with the formation of hydrogenic impurity centers.

S. Dzhumanov; O. K. Ganiev; Z. S. Khudayberdiev

2010-08-13T23:59:59.000Z

247

Scaling at the Energy-driven Metal-Insulator Transition and  

E-Print Network (OSTI)

The electronic properties of disordered systems at the Anderson metal-insulator transition (MIT) have been the subject of intense study for several decades. Thermoelectric properties at the MIT, such as thermopower and thermal conductivity, however, have been relatively neglected. Using the recursive Green’s function method and the Chester-Thellung-Kubo-Greenwood formalism, we calculate numerically the low temperature behaviour of all kinetic coefficients Lij. From these we can deduce for example the electrical conductivity ? and the thermopower S at finite temperatures. Here we present results for the case of completely coherent transport in cubic 3D systems. Copyright line will be provided by the publisher 1 Introduction The Anderson model [1] is widely used to investigate the phenomenon of localisation in disordered materials. Especially the possibility of a quantum phase transition driven by disorder from an insulating phase, where all states are localised, to a metallic phase with extended states has lead to extensive analytical and numerical investigations of the critical properties of this metal-insulator transition (MIT) [2].

The Thermoelectric Power; Er Croy; Rudolf A. Römer

2005-01-01T23:59:59.000Z

248

Synthesis of Nano-Structured Metal-Oxides and Deposition via Ink ...  

Science Conference Proceedings (OSTI)

The objective of this study was to synthesize numerous metal oxide nano- structures including TiO2, Nb-doped TiO2, and SnO2 and deposit these materials on ...

249

Recovery of Metal Oxides From Fly Ash, Volumes 1-3  

Science Conference Proceedings (OSTI)

By processing fly ash to obtain metal oxides and other commercial products, utilities can realize both sales revenues and reduced disposal costs. A commercial-scale processing plant could be ready for demonstration by 1992.

1984-06-01T23:59:59.000Z

250

Design and construction of rigs for studying surface condensation and creating anodized metal oxide surfaces  

E-Print Network (OSTI)

This thesis details the design and construction of a rig for studying surface condensation and a rig for creating anodized metal oxides (AMOs). The condensation rig characterizes condensation for different surfaces; this ...

Sun, Wei-Yang

2011-01-01T23:59:59.000Z

251

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

Science Conference Proceedings (OSTI)

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

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

2001-01-01T23:59:59.000Z

252

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

253

Porous desulfurization sorbent pellets containing a reactive metal oxide and an inert zirconium compound  

DOE Patents (OSTI)

Sorbent pellets for removing hydrogen sulfide from coal gas are prepared by combining a reactive oxide, in particular zinc oxide, with a zirconium compound such as an oxide, silicate, or aluminate of zirconium, and an inorganic binder and pelletizing and calcining the mixture. Alternately, the zinc oxide may be replaced by copper oxide or a combination of copper, molybdenum, and manganese oxides. The pellet components may be mixed in dry form, moistened to produce a paste, and converted to pellets by forming an aqueous slurry of the components and spray drying the slurry, or the reactive oxide may be formed on existing zirconium-containing catalyst-carrier pellets by infusing a solution of a salt of the active metal onto the existing pellets and firing at a high temperature to produce the oxide. Pellets made according to this invention show a high reactivity with hydrogen sulfide and durability such as to be useful over repeated cycles of sorption and regeneration.

Gardner, Todd H.; Gasper-Galvin, Lee D.

1996-12-01T23:59:59.000Z

254

Towards Sustainable Metals Production by Molten Oxide Electrolysis  

Science Conference Proceedings (OSTI)

Liquid-metal/molten-salt cells have been shown to operate as rechargeable batteries that have the potential to handle colossal currents thereby enabling us to ...

255

Platinum Group Metal Oxide Absorption Properties of Perovskite ...  

Science Conference Proceedings (OSTI)

In this study, the absorption properties of various perovskite-type oxide is .... Influence of Different Cooling Structure on Surface Crack of HSLA Steel Plate by

256

DEVELOPMENT OF GLASS COMPOSITIONS TO IMMOBILIZE ALKALI, ALKALINE EARTH, LANTHANIDE AND TRANSITION METAL FISSION PRODUCTS FROM NUCLEAR FUEL REPROCESSING  

Science Conference Proceedings (OSTI)

The Advanced Fuel Cycle Initiative (AFCI) waste management strategy revolves around specific treatment of individual or groups of separated waste streams. A goal for the separations processes is to efficiently manage the waste to be dispositioned as high level radioactive waste. The Advanced Fuel Cycle Initiative (AFCI) baseline technology for immobilization of the lanthanide (Ln) and transition metal fission product (TM) wastes is vitrification into a borosilicate glass. A current interest is to evaluate the feasibility of vitrifying combined waste streams to most cost effectively immobilize the wastes resulting from aqueous fuel reprocessing. Studies showed that high waste loadings are achievable for the Ln only (Option 1) stream. Waste loadings in excess of 60 wt % (on a calcined oxide basis) were demonstrated via a lanthanide borosilicate (LaBS) glass. The resulting glasses had excellent relative durability as determined by the Product Consistency Test (PCT). For a combined Ln and TM waste stream glass (Option 2), noble metal solubility was found to limit waste loading. However, the measured PCT normalized elemental releases for this glass were at least an order of magnitude below that of Environmental Assessment (EA) glass. Current efforts to evaluate the feasibility of vitrifying combined Ln, TM, alkali (Cs is the primary radionuclide of concern) and alkaline earth (Sr is the primary radionuclide of concern) wastes (Option 3) have shown that these approaches are feasible. However, waste loading limitations with respect to heat load (Cs/Sr loading), molybdenum solubility and/or noble metal solubility will likely be realized and must be considered in determining the cost effectiveness of these approaches.

Marra, J.; Billings, A.

2009-06-24T23:59:59.000Z

257

Measurement of the Nickel/Nickel Oxide Phase Transition in High Temperature Hydrogenated Water Using the Contact Electric Resistance (CER) Technique  

DOE Green Energy (OSTI)

Prior studies of Alloy 600 and Alloy X-750 have shown the existence of a maximum in stress corrosion cracking (SCC) susceptibility in high temperature water (e.g., at 360 C), when testing is conducted over a range of dissolved (i.e., aqueous) hydrogen (H{sub 2}) concentrations. It has also been shown that this maximum in SCC susceptibility tends to occur in proximity to the nickel/nickel oxide (Ni/NiO) phase transition, suggesting that oxide phase stability may affect primary water SCC (PWSCC) resistance. Previous studies have estimated the Ni/NiO transition using thermodynamic calculations based on free energies of formation for NiO and H{sub 2}O. The present study reports experimental measurements of the Ni/NiO transition performed using a contact electric resistance (CER) instrument. The CER is capable of measuring the surface resistance of a metal to determine whether it is oxide-covered or oxide-free at a given condition. The transition aqueous hydrogen (H{sub 2}) concentration corresponding to the Ni/NiO equilibrium was measured at 288, 316, 338 and 360 C using high purity Ni specimens. The results showed an appreciable deviation (i.e., 7 to 58 scc H{sub 2}/kg H{sub 2}O) between the measured Ni/NiO transition and the theoretical Ni/NiO transition previously calculated using free energy data from the Journal of Solution Chemistry. The CER-measured position of the Ni/NiO transition is in good agreement with the maxima in PWSCC susceptibility at 338 and 360 C. The measured Ni/NiO transition provides a reasonable basis for estimating the aqueous H{sub 2} level at which the maximum in SCC susceptibility is likely to be observed at temperatures lower than 338 to 360 C, at which SCC tests are time-consuming to perform. Limited SCC data are presented which are consistent with the observation that SCC susceptibility is maximized near the Ni/NiO transition at 288 C.

S.A. Attanasio; D.S. Morton; M.A. Ando; N.F. Panayotou; C.D. Thompson

2001-05-08T23:59:59.000Z

258

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

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

Transition-Metal Strings Templated on Boron-Doped Carbon Nanotubes: A DFT Investigation  

SciTech Connect

The binding nature, magnetic, and electronic properties of transition-metal (TM) monatomic chains anchored on boron-doped single-walled carbon nanotubes (B-SWCNTs) are studied using density-functional theory. The TM systems studied here include Au, Pt, Ru, Pd, Ag, Co, Ni, Cu, W, and Ti, which are well-known for their technical importance. In conjunction, prototype semiconducting SWCNT(8,0) and metallic SWCNT(6,6) were chosen to model the general features of B-doped SWCNTs. It is found that the TM-strings exhibit well-defined covalent bonds with the boron-doped SWCNTs, in contrast to the pristine SWCNTs. The TMstring/ B-SWCNT composites exhibit high stability and unexpected electronic properties, which are relevant to applications in nanoelectronics, spintronics, nanocatalysis, and sensor devices.

An, Wei; Turner, C. H.

2009-08-27T23:59:59.000Z

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

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

262

Study of intermediates from transition metal excited-state electron-transfer reactions  

SciTech Connect

Conventional and fast-kinetics techniques of photochemistry, photophysics, radiation chemistry, and electrochemistry were used to study the intermediates involved in transition metal excited-state electron-transfer reactions. These intermediates were excited state of Ru(II) and Cr(III) photosensitizers, their reduced forms, and species formed in reactions of redox quenchers and electron-transfer agents. Of particular concern was the back electron-transfer reaction between the geminate pair formed in the redox quenching of the photosensitizers, and the dependence of its rate on solution medium and temperature in competition with transformation and cage escape processes. (DLC)

Hoffman, M.Z.

1992-07-31T23:59:59.000Z

263

The chemical control of high-TC superconductivity: metal-superconductor-insulator transition in (Tl1-yPby)Sr2(Ca1-xYx)Cu2O7  

Science Conference Proceedings (OSTI)

Keywords: (Tl,Pb)-1212, Hall effect, Mott criterion, metal-insulator transition, resistivity, strontium, yttrium

R. S. Liu; P. P. Edwards; S. F. Hu; D. A. Jefferson; Y. T. Huang; S. F. Wu; M.-J. Tsai

1993-10-01T23:59:59.000Z

264

Aerosol synthesis of nano and micro-scale zero valent metal particles from oxide precursors  

SciTech Connect

In this work a novel aerosol method, derived form the batch Reduction/Expansion Synthesis (RES) method, for production of nano / micro-scale metal particles from oxides and hydroxides is presented. In the Aerosol-RES (A-RES) method, an aerosol, consisting of a physical mixture of urea and metal oxide or hydroxides, is passed through a heated oven (1000 C) with a residence time of the order of 1 second, producing pure (zero valent) metal particles. It appears that the process is flexible regarding metal or alloy identity, allows control of particle size and can be readily scaled to very large throughput. Current work is focused on creating nanoparticles of metal and metal alloy using this method. Although this is primarily a report on observations, some key elements of the chemistry are clear. In particular, the reducing species produced by urea decomposition are the primary agents responsible for reduction of oxides and hydroxides to metal. It is also likely that the rapid expansion that takes place when solid/liquid urea decomposes to form gas species influences the final morphology of the particles.

Phillips, Jonathan [Los Alamos National Laboratory; Luhrs, Claudia [UNM; Lesman, Zayd [UNM; Soliman, Haytham [UNM; Zea, Hugo [UNM

2010-01-01T23:59:59.000Z

265

A New Mechanism of Charge Density Wave Discovered in Transition Metal  

NLE Websites -- All DOE Office Websites (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.

266

Sulfidation of mixed metal oxides in a fluidized-bed reactor  

SciTech Connect

Mixed metal oxides were used for the removal of hydrogen sulfide from a hot gas stream. Sorbents were prepared according to the dry and wet impregnation techniques. The desulfurization performance of the metal oxide sorbents was experimentally tested in a fluidized-bed reactor system. Sulfidation experiments performed under reaction conditions similar to those at the exit of a coal gasifier showed that the preparation procedure and technique, the type and the amount of the impregnated metal oxide, the type of the solid carrier, and the size of the solid reactant affect the H[sub 2]S removal capacity of the sorbents. The pore structure of fresh and sulfided sorbents was analyzed using mercury porosimetry, nitrogen adsorption, and scanning electron microscopy.

Christoforou, S.C.; Efthimiadis, E.A.; Vasalos, I.A. (Aristotelian Univ. of Thessaloniki (Greece))

1995-01-01T23:59:59.000Z

267

Noble Metal Catalysts for Mercury Oxidation in Utility Flue Gas: Gold, Palladium and Platinum Formulations  

Science Conference Proceedings (OSTI)

The use of noble metals as catalysts for mercury oxidation in flue gas remains an area of active study. To date, field studies have focused on gold and palladium catalysts installed at pilot scale. In this article, we introduce bench-scale experimental results for gold, palladium and platinum catalysts tested in realistic simulated flue gas. Our initial results reveal some intriguing characteristics of catalytic mercury oxidation and provide insight for future research into this potentially important process.

Presto, A.A.; Granite, E.J

2008-07-01T23:59:59.000Z

268

Metal oxide coatings for piezoelectric exhaust gas sensors  

DOE Green Energy (OSTI)

We have deposited ZrO{sub 2}, TiO{sub 2}, and SnO{sub 2} films on ST-cut quartz surface acoustic wave (SAW) devices via sol-gel techniques. The films range from 100 to 300 nm thick and have porosities after calcination at 300{degrees}C that range from 82-88 % for ZrO{sub 2}, 77-81% for TiO{sub 2}, and 57-66% for SnO{sub 2}. In all cases, we have varied the synthesis and processing parameters over a wide range to optimize film properties: metal ion concentration (0.05-1.0 M), the H{sub 2}O:metal ratio (0.3-5.3), the acid concentration in the sol (0.02-0.7 M), the modifier ligand:metal ratio (r = 0.0-1.0), the processing conditions (100-900{degrees}C). The modifier ligand, triethanolamine (TEA), is added to each solution to allow multilayer films to be made crack free. The multilayer films are studied by optical microscopy, ellipsometry, X-ray diffraction, and N{sub 2} sorption. Preliminary high temperature frequency response measurements to target gases, such as, H{sub 2}, NO, NO{sub 2}, and propylene indicate limited sensitivity for the configurations tested.

Anderson, M.T.; Cernosek, R.W.

1996-06-01T23:59:59.000Z

269

METAL INTERCONNECTS FOR SOLID OXIDE FUEL CELL POWER SYSTEMS  

DOE Green Energy (OSTI)

Interconnect development is identified by the U.S. Department of Energy as a key technical area requiring focused research to meet the performance and cost goals under the Solid State Energy Conversion Alliance initiative. In the Phase I SECA Core Technology Program, Ceramatec investigated a commercial ferritic stainless steel composition for oxidation resistance properties by measuring the weight gain when exposed to air at the fuel cell operating temperature. A pre-treatment process that results in a dense, adherent scale was found to reduce the oxide scale growth rate significantly. A process for coating the surface of the alloy in order to reduce the in-plane resistance and potentially inhibit chromium oxide evaporation was also identified. The combination of treatments provided a very low resistance through the scale. The resistance measured was as low as 10 milliohm-cm{sup 2} at 750 C in air. The oxide scale was found to be stable in humidified air at 750 C. The resistance value was stable over several thermal cycles. A similar treatment and coating for the fuel side of the interconnect also showed an exceptionally low resistance of one milliohm-cm{sup 2} in humidified hydrogen at 750 C, and was stable through multiple thermal cycles. Analysis of the scale after exposure to various atmospheres showed the presence of a stable composition. When exposed to a dual (air and hydrogen) atmosphere however, the scale composition contains a mixture of phases. Based on results to-date, the alloy selection and the treatment processes appear to be well suited for SOFC interconnect application.

S. Elangovan; S. Balagopal; M. Timper; I. Bay; D. Larsen; J. Hartvigsen

2003-10-01T23:59:59.000Z

270

Electrical and physical characteristics of HfLaON-gated metal-oxide-semiconductor capacitors with various nitrogen concentration profiles  

Science Conference Proceedings (OSTI)

The comparative studies of electrical and physical characteristics of HfLaON-gated metal-oxide-semiconductor (MOS) capacitors with various nitrogen concentration profiles (NCPs) were investigated. Various NCPs in HfLaON gate dielectrics were adjusted ... Keywords: Charge trapping, Current-conduction, High-k dielectric, Metal-oxide-semiconductor (MOS), Nitrogen concentration profiles (NCPs)

Chin-Lung Cheng; Jeng-Haur Horng; Hung-Yang Tsai

2011-02-01T23:59:59.000Z

271

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 and SnO2 play a central role in solar energy conversion applications.1­7 In fact, the discovery of low-cost high-efficiency dye-sensitized solar cells (DSSCs) (i.e., exceeding 10% solar-to-electric energy

272

The Use of Soluble Polyolefins as Supports for Transition Metal Catalysts  

E-Print Network (OSTI)

The use of polymer supports for transition metal catalysts are very important and useful in synthetic organic chemistry as they make possible the separation and isolation of catalysts and products quite easy. These polymer-bound ligands/catalysts/reagents can, often, be recovered and recycled numerous times and typically yield products in high purity, negating the need for further purification steps (i.e. column chromatography). Because of this, interest in these systems has garnered international attention in the scientific community as being “Green”. Historically, insoluble, polymer-supports (i.e. Merrifield resin) were used to develop recoverable catalysts. This has the advantage of easy separation and isolation from products after a reaction; because of their insolubility, such supported catalysts can be easily removed by gravity filtration. However, these catalysts often have relatively poor reactivity and selectivity when compared to homogeneous catalysts. Because of this disadvantage, our lab has had interest in the development of soluble polymer-supports for transition metal catalysts. We have developed several separation methods for these soluble polymer-bound catalysts. These include thermomorphic liquid/liquid and solid/liquid as well as latent biphasic liquid/liquid separation techniques. This dissertation describes the use of both, latent biphasic liquid/liquid separation systems and thermomorphic solid/liquid separation systems. In order to perform a latent biphasic iii liquid/liquid separation, a polymer-bound catalyst must have a very high selectivity for one liquid phase over the other. Our lab has pioneered the use of polyisobutylene (PIB) oligomers as supports for transition metal catalysts. Previous work has shown that these oligomers are > 99.96 % phase selectively soluble in nonpolar solvents. This has allowed us to prepare PIB-supported salen Cr(III) complexes that can be used in a latent biphasic liquid/liquid solvent system. The synthesis of these complexes is quite straightforward and such species can be characterized using solution state 1H and 13C NMR spectroscopy. Also, these complexes can be used to catalyze the ring opening of meso epoxides with azidotrimethylsilane (TMS-N3) and can be recovered and recycled up to 6 times, with no loss in catalytic activity. To perform a thermomorphic solid/liquid separation, a polymer-bound catalyst that is completely insoluble at room temperature but soluble upon heating must be used. Our lab has pioneered the use of polyethylene oligomers (PEOlig) as supports for transition metal catalysts. Such PEOlig-supported catalysts are able perform homogeneous catalytic reactions at elevated temperatures (ca. 65 ?C), but, upon cooling, precipitate out of solution as solids while the products stay in solution. This process allows for the easy separation of a solid catalyst from the product solution. Described herein, is the development of PEOlig-supported salen-Cr(III) complexes and PEOlig-supported NHC-Ru complexes. The preparation of these complexes is also straightforward and such species can be characterized using solution state variable temperature (VT) 1H and 13C NMR spectroscopy. In the case of the PEOlig-supported salen-Cr(III) complex, it was found to be a recoverable/recyclable catalyst for the ring opening of epoxides with TMS-N3 and could be reused 6 times with no loss in activity. The PE-supported NHC-Ru complex was able to be used as a recyclable ring closing metathesis (RCM) catalyst and could be used up to 10 times.

Hobbs, Christopher Eugene

2011-08-01T23:59:59.000Z

273

Study of intermediates from transition metal excited-state electron-transfer reactions  

SciTech Connect

During this period, conventional and fast-kinetics techniques of photochemistry, photophysics, radiation chemistry, and electrochemistry were used for the characterization of the intermediates that are involved in transition metal excited-state electron-transfer reactions. The intermediates of interest were the excited states of Ru(II) and Cr(III) photosensitizers, their reduced forms, and the species formed in the reactions of redox quenchers and electron-transfer agents. Of particular concern has been the back electron-transfer reaction between the geminate pair formed in the redox quenching of the photosensitizers, and the dependence of its rate on solution medium and temperature in competition with transformation and cage escape processes.

Hoffman, M.Z.

1991-12-31T23:59:59.000Z

274

Surfactant-modified diffusion on transition-metal surfaces (reprinted with the addition of the appendices)  

DOE Green Energy (OSTI)

Wanting to convert surface impurities from a nuisance to a systematically applicable nano-fabrication tool, the authors have sought to understand how such impurities affect self-diffusion on transition-metal surfaces. Their field-ion microscope experiments reveal that in the presence of surface hydrogen, self-diffusion on Rh(100) is promoted, while on Pt(100), not only is it inhibited, but its mechanism changes. First-principles calculations aimed at learning how oxygen fosters perfect layerwise growth on a growing Pt(111) crystal contradict the idea in the literature that it does so by directly promoting transport over Pt island boundaries. The discovery that its real effect is to burn off adventitious adsorbed carbon monoxide demonstrates the predictive value of state-of-the-art calculation methods.

FEIBELMAN,PETER J.; KELLOGG,GARY LEE

2000-03-01T23:59:59.000Z

275

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

DOE Green Energy (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

276

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

277

Syntheses and applications of soluble polyisobutylene (PIB)-supported transition metal catalysts  

E-Print Network (OSTI)

Soluble polymer supports facilitate the recovery and recycling of expensive transition metal complexes. Recently, polyisobutylene (PIB) oligomers have been found to be suitable polymer supports for the recovery of a variety of transition metal catalysts using liquid/liquid biphasic separations after a homogeneous reaction. Our work has shown that PIB-supported Ni(II) and Co(II) ?-diketonates prepared from commercially available vinyl terminated PIB oligomers possess catalytic activity like that of their low molecular weight analogs in Mukaiyama epoxidation of olefins. Carboxylic acid terminated PIB derivatives can act as carboxylate ligands for Rh(II) cyclopropanation catalysts. An achiral PIB-supported Rh(II) carboxylate catalyst showed good activity in cyclopropanation of styrene in hydrocarbon solvents, and could be easily recycled nine times by a post reaction extraction. Further application of PIB supports in asymmetric cyclopropanation reactions were investigated using PIBsupported arenesulfonyl Rh(II) prolinates derived from L-proline as examples. The PIBsupported chiral Rh carboxylates demonstrated moderate activity and were recovered and reused for four to five cycles. The prolinate catalyst prepared from PIB-anisole also showed encouraging enantioselectivity and about 8% ee and 13% ee were observed on trans- and cis-cyclopropanation product respectively. Finally, PIB oligomers can be modified in a multi step sequence to prepare PIBsupported chiral bisoxazolines that can in turn be used to prepare active, recyclable PIBsupported Cu(I) bisoxazoline complexes for olefin cyclopropanation. These chiral copper catalysts showed moderate catalytic activity and good stereoselectivity in cyclopropanation of styrene. A chiral ligand prepared from D-phenylglycinol provided the most effective stereo control and gave the trans- and cis-cyclopropanation product in 94% ee and 68% ee respectively. All three PIB-supported chiral bisoxazoline-Cu(I) catalysts could be reused five to six times.

Tian, Jianhua

2008-12-01T23:59:59.000Z

278

Production of hydrogen. [metals oxidation/carbon reduction process; and cyyclic electrolytic; carbon reduction  

SciTech Connect

Hydrogen is produced in a cyclic metals oxidation/carbon reduction process. In particular, elemental iron or cobalt is oxidized in an aqueous solution of an alkali metal hydroxide with the simultaneous generation of hydrogen. The iron or cobalt oxidation products of the reaction are thereafter reduced to elemental iron or cobalt by contact with a carbonaceous reducing agent at elevated temperatures and the reduced material recycled for reoxidation. In an alternate operation, hydrogen is produced in a cyclic electrolytic/carbon reduction process wherein elemental iron or cobalt is electrolytically converted to corresponding oxidation products with the simultaneous generation of hydrogen. The electrolytic cell used in this process comprises a cathode, a magnetic anode that is adapted to attract and retain iron and/or cobalt particles and an aqueous electrolyte. In the electrolytic cell, hydrogen is produced at the cathode and metal particles contained on the magnetic electrode are oxidized to a non-ferromagnetic specie, such as ferrous hydroxide. The nonferromagnetic species are recovered from the electrolytic cell and thereafter reconverted to particulate elemental iron and/or cobalt by treating the material with a carbonaceous reductant at an elevated temperature.

Batzold, J.S.; Pan, Y.

1980-05-13T23:59:59.000Z

279

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

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

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

280

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

SciTech Connect

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

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

Trends in Selective Hydrogen Peroxide Production on Transition Metal Surfaces from First Principles  

Science Conference Proceedings (OSTI)

We present a comprehensive, Density Functional Theory-based analysis of the direct synthesis of hydrogen peroxide, H2O2, on twelve transition metal surfaces. We determine the full thermodynamics and selected kinetics of the reaction network on these metals, and we analyze these energetics with simple, microkinetically motivated rate theories to assess the activity and selectivity of hydrogen peroxide production on the surfaces of interest. By further exploiting Brønsted-Evans-Polanyi relationships and scaling relationships between the binding energies of different adsorbates, we express the results in the form of a two dimensional contour volcano plot, with the activity and selectivity being determined as functions of two independent descriptors, the atomic hydrogen and oxygen adsorption free energies. We identify both a region of maximum predicted catalytic activity, which is near Pt and Pd in descriptor space, and a region of selective hydrogen peroxide production, which includes Au. The optimal catalysts represent a compromise between activity and selectivity and are predicted to fall approximately between Au and Pd in descriptor space, providing a compact explanation for the experimentally known performance of Au-Pd alloys for hydrogen peroxide synthesis, and suggesting a target for future computational screening efforts to identify improved direct hydrogen peroxide synthesis catalysts. Related methods of combining activity and selectivity analysis into a single volcano plot may be applicable to, and useful for, other aqueous phase heterogeneous catalytic reactions where selectivity is a key catalytic criterion.

Rankin, Rees B.; Greeley, Jeffrey P.

2012-10-19T23:59:59.000Z

282

Half-Metallicity in Europium Oxide Conductively Matched with Silicon  

SciTech Connect

EuO1-x--a remarkably versatile ferromagnetic semiconductor with variable transport properties--incorporated into a heterostructure with n+ doped silicon is shown to be {approx}90% spin polarized by Andreev reflection (AR) spin spectroscopy. The AR measurements were done in a planar geometry with an InSn superconducting film. A simple reactive growth technique was used to controllably introduce oxygen vacancies into EuO1-x to adjust its carrier concentration. We demonstrate by direct measurements of spin polarization that half-metallicity of EuO1-x can be achieved in the films conductively matched with Si, thus making EuO1-x one of the most attractive materials for silicon-based spintronics.

Panguluri,R.; Santos, T.; Negusse, E.; Dvorak, J.; Idzerda, Y.; Moodera, J.; Nadgorny, B.

2008-01-01T23:59:59.000Z

283

Niobium Oxide-Metal Based Seals for High Temperature Applications  

Science Conference Proceedings (OSTI)

The present final report describes technical progress made in regards to evaluating niobium oxide/alumina as a high temperature seal material. Fabrication and characterization of specimens comprising niobium oxide and alumina composites of various compositions was performed. The goal was to identify regions where a glass formed. There were no experimental conditions where a glassy phase was unequivocally identified. However, the results led to the formation of an interesting class of fibrous composites which may have applications where high compliance and high toughness are needed. It is clear that vapor phase sintering is an active mass transport mechanism in Nb{sub 2}O{sub 5}-Al{sub 2}O{sub 3} composites (Figure 1), and it may be possible to design porous materials by utilizing vapor phase sintering. The compositions evaluated in the present work are 52, 60, 73, 82 and 95 mol. % Nb{sub 2}O{sub 5} with the remainder Al{sub 2}O{sub 3}. These were chosen so that some eutectic composition was present during cooling, in an attempt to encourage glass formation. However, the presence of large, elongated crystals, both in the slow cool and the quench experiments indicates that the driving force for crystallization is very high. Several joints were formed between high purity alumina with two compositions (60 and 82 mol. %) forming the joint. These were created by grinding and polishing alumina surfaces and stacking them end-to-end with the powdered Nb{sub 2}O{sub 5}-Al{sub 2}O{sub 3} material in between. Joining was accomplished in air at temperatures between 1400 C and 1450 C. The joints failed during subsequent machining for strength bars, indicating low strength. It may be possible to use the compositions evaluated here as a joint material, but it seems unlikely that a glassy phase could be produced while joining.

Ivar Reimanis

2006-08-14T23:59:59.000Z

284

Final Scientific Report : Development of Transition Metal/ Chalcogen Based Cathode Catalysts for PEM Fuel Cells  

DOE Green Energy (OSTI)

The aim of this project was to investigate the potential for using base metal sulfides and selenides as low cost replacements for precious metal catalysts, such as platinum, currently being used in PEM fuel cells. The approach was to deposit thin films of the materials to be evaluated onto inert electrodes and evaluate their activity for the cathode reaction (oxygen reduction) as well as ex-situ structural and compositional characterization. The most active materials identified are CoS2 and the 50:50 solid solution (Co,Ni)S2. However, the OCP of these materials is still considered too low, at 0.83V and 0.89V vs. RHE respectively, for testing in fuel cells. The methods employed here were necessary to compare with the activity of platinum as, when nano-dispersed on carbon supports, the active surface area of these materials is difficult to measure, making comparisons inaccurate. This research adds to the knowledge of potential candidates for platinum replacement in order to reduce the cost of PEM fuel cell technology and promote commercialization. Although the fabrication methods employed here are strictly experimental, methods were also developed to produce nano-dispersed catalysts with similar compositions, structure and activity. Cycling of these catalysts to highly oxidizing potentials resulted in an increase of the open circuit voltage to approach that of platinum, however, it proved difficult to determine why using these dispersed materials. The potential for non-precious, non-metallic, low cost, compound catalysts for PEM fuel cells has been investigated and demonstrated.

Campbell, Stephen, A.

2008-02-29T23:59:59.000Z

285

Composition-tailored synthesis of gradient transition metal precursor particles for lithium-ion battery cathode materials.  

DOE Green Energy (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

286

Method for removing heavy metal and nitrogen oxides from flue gas, device for removing heavy metal and nitrogen oxides from flue gas  

DOE Patents (OSTI)

A method for the simultaneous removal of oxides and heavy metals from a fluid is provided comprising combining the fluid with compounds containing alkali and sulfur to create a mixture; spray drying the mixture to create a vapor phase and a solid phase; and isolating the vapor phase from the solid phase. A device is also provided comprising a means for spray-drying flue gas with alkali-sulfide containing liquor at a temperature sufficient to cause the flue gas to react with the compounds so as to create a gaseous fraction and a solid fraction and a means for directing the gaseous fraction to a fabric filter.

Huang, Hann-Sheng; Livengood, Charles David

1997-12-01T23:59:59.000Z

287

Catalytic hydrocarbon reactions over supported metal oxides. Progress report, April 1, 1994--January 31, 1995  

DOE Green Energy (OSTI)

Oxide catalysis plays a central role in hydrocarbon processing and improvements in catalytic activity or selectivity are of great technological importance because these improvements will translate directly into more efficient utilization of hydrocarbon supplies and lower energy consumption in separation processes. An understanding of the relationships between surface structure and catalytic properties is needed to describe and improve oxide catalysts. Our approach has been to prepare supported oxides that have a specific structure and oxidation state and then employ these structures in reaction studies. Our current research program is focused on studying the fundamental relationships between structure and reactivity for two important reactions that are present in many oxide-catalyzed processes, partial oxidation and carbon-carbon bond formation. Oxide catalysis can be a complex process with both metal cation and oxygen anions participating in the chemical reactions. From an energy perspective carbon-carbon bond formation is particularly relevant to CO hydrogenation in isosynthesis. Hydrogenolysis and hydrogenation form the basis for heteroatom removal in fuels processing. Understanding the catalysis of these processes (and others) requires isolating reaction steps in the overall cycle and determining how structure and composition influence the individual reaction steps. Specially designed oxides, such as we use, permit one to study some of the steps in oxidation, carbon-carbon coupling and heteroatom removal catalysis. During the course of our studies we have: (1) developed methods to form and stabilize various Mo and W oxide structures on silica; (2) studied C-H abstraction reactions over the fully oxidized cations; (3) studied C-C bond coupling by methathesis and reductive coupling of aldehydes and ketones over reduced cation structures; and (4) initiated a study of hydrogenation and hydrogenolysis over reduced cation structures.

Ekerdt, J.G.

1995-01-31T23:59:59.000Z

288

A unified view of coherent and incoherent dihydrogen exchange in transition metal hydrides by nuclear resonance and inelastic neutron scattering  

SciTech Connect

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

289

Metal oxide coating of carbon supports for supercapacitor applications.  

DOE Green Energy (OSTI)

The global market for wireless sensor networks in 2010 will be valued close to $10 B, or 200 M units. TPL, Inc. is a small Albuquerque based business that has positioned itself to be a leader in providing uninterruptible power supplies in this growing market with projected revenues expected to exceed $26 M in 5 years. This project focused on improving TPL, Inc.'s patent-pending EnerPak{trademark} device which converts small amounts of energy from the environment (e.g., vibrations, light or temperature differences) into electrical energy that can be used to charge small energy storage devices. A critical component of the EnerPak{trademark} is the supercapacitor that handles high power delivery for wireless communications; however, optimization and miniaturization of this critical component is required. This proposal aimed to produce prototype microsupercapacitors through the integration of novel materials and fabrication processes developed at New Mexico Technology Research Collaborative (NMTRC) member institutions. In particular, we focused on developing novel ruthenium oxide nanomaterials and placed them into carbon supports to significantly increase the energy density of the supercapacitor. These improvements were expected to reduce maintenance costs and expand the utility of the TPL, Inc.'s device, enabling New Mexico to become the leader in the growing global wireless power supply market. By dominating this niche, new customers were expected to be attracted to TPL, Inc. yielding new technical opportunities and increased job opportunities for New Mexico.

Boyle, Timothy J.; Tribby, Louis, J (University of New Mexico, Albuquerque, NM); Lakeman, Charles D. E. (TPL, Inc., Albuquerque, NM); Han, Sang M. (University of New Mexico, Albuquerque, NM); Lambert, Timothy N.; Fleig, Patrick F. (TPL, Inc., Albuquerque, NM)

2008-07-01T23:59:59.000Z

290

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

291

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

292

NiO as a peculiar support for metal nanoparticles in polyols oxidation  

SciTech Connect

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

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

2013-01-01T23:59:59.000Z

293

Brazing a Mixed Ionic/Electronic Conductor to an Oxidation Resistant Metal  

DOE Green Energy (OSTI)

Mixed ionically/electrically conducting oxides such as lanthanum calcium manganate are currently being investigated for use as electrodes in a number of high temperature devices, including solid oxide fuel cells. Traditionally, glass seals have been employed as a means of hermetically joining the ceramic components that lie at the heart of these devices to the heat resistant metal frame that gives the device its structural integrity. The present paper outlines an alternative brazing technique for joining these dissimilar materials and discusses recent findings regarding the wettability of the braze on the two joining surfaces, as well as the strength of the resulting joint.

Weil, K. Scott; Hardy, John S.

2003-09-05T23:59:59.000Z

294

Investigation of Molecular Magnetic Compounds Incorporating 4d and 5d Transition Metal Cyanometallates  

E-Print Network (OSTI)

The field of molecular magnetism has expanded rapidly since the discovery of single molecule magnets (SMMs) in the 1990’s and has witnessed extraordinary advances in the last several decades. One of the current trends in molecular magnetic research is to incorporate metal ions that have pronounced single-ion anisotropy in an effort to improve magnetic exchange interactions. The 4d and 5d transition metal ions have large spin-orbit coupling parameters which contribute to the orbital angular momentum effects that lead to anisotropic behavior. The work herein describes efforts to synthesize and characterize new cyanide-bridged molecular materials incorporating 4d and 5d transition metal ions, specifically the [Os(CN)_(6)]^(3-), [Mo(CN)_(6)]^(3-) and [W(CN)_(8)]^(3-) ions. The 5d hexacyanometallate [Os(CN)_(6)]^(3-) was incorporated into a trinuclear cyanide bridged molecule and the [Fe(CN)_(6)]^(3-) analog was prepared as a reference compound for assessing the effect of the 5d versus 3d metal ion on the magnetic properties. Both molecules exhibit SMM bistability with a pronounced increase (~90 %) in the blocking temperature (TB) of the OsIII analogue. In addition to typical SMM behavior, both compounds exhibit exchange-biased SMM behavior, a shift in the quantum tunneling of the magnetization (QTM) from zero field. This exchange-bias can be turned “on” or “off” depending on the presence of interstitial methanol molecules. New trigonal bipyramidal (TBP) molecules incorporating the rarely studies hexacyanomolybdate(III) ion are presented in chapter III of this dissertation. The molecules of general formula [M(tmphen)_(2)]_(3)[Mo(CN)_(6)]_(2) (M = V^(II), Mn^(II) and Fe^(II); tmphen = 3,4,7,8-tetramethyl-1,10-phenanthroline), represent additions to a large homologous family of TBP molecules reported by the Dunbar group over the years. The [Mo(CN)_(6)]^(3-) ion was prepared in situ by loss of one cyanide ligand from [Mo(CN)_(7)]^(4-). Of particular interest among the compounds reported is the V_(3)Mo_(2) analog which exhibits extraordinarily strong antiferromagnetic coupling (estimated J = -134 cm^(-1). The observed exchange coupling parameter is more than twice the current record for the antiferromagnetic coupling parameter for a cyanide-bridged magnetic molecule. Another set of results were obtained using the octacyanometallate anion [WV(CN)_(8)]^(3-) as a building block for the synthesis and magnetic studies of a family of new cyanide-bridged magnetic materials. The compounds exhibit several different structural motifs including three 0-D molecular compounds (two pentanuclear molecules and a linear trinuclear molecule) and a 1-D chain, findings that illustrate the structural versatility of the octacyanotungstate(V) ions. The TBP molecule, [Mn(tmphen)_(2)]_(3)[W(CN)_(8)]_(2), exhibits evidence for an out-of-phase signal when subjected to ac measurements in zero applied field. The 1-D chain also reveals evidence for the beginning of an out-of-phase signal under zero applied field which hints at single chain magnet behavior.

Southerland, Heather Irene

2013-08-01T23:59:59.000Z

295

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

DOE Green Energy (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

296

Investigation on Durability and Reactivity of Promising Metal Oxide Sorbents During Sulfidation and Regeneration  

SciTech Connect

Research activities and efforts of this research project were concentrated on formulating various metal oxide sorbents with various additives under various formulation conditions, conducting experiments on initial reactivity of formulated sorbents with hydrogen sulfide, and testing hardness of formulated sorbents. Experiments on reactivity of formulated metal oxide sorbents with wet hydrogen sulfide contained in a simulated coal gas mixture were carried out for 120 seconds at 550 o C (see Table 1) to evaluate reactivity of formulated sorbents with hydrogen sulfide. Hardness of formulated sorbents was evaluated in addition to testing their reactivity with hydrogen sulfide. A typical simulated coal gas mixture consists of 9107-ppm hydrogen sulfide (0.005 g; 1 wt %), 0.085-g water (15.84 wt %), 0.0029-g hydrogen (0.58 wt %), and 0.4046-g nitrogen (81.34 wt%).

K. C. Kwon

1997-05-01T23:59:59.000Z

297

Removal of NOx or its conversion into harmless gases by charcoals and composites of metal oxides  

SciTech Connect

In recent years, much attention has been devoted to environmental problems such as acid rain, photochemical smog and water pollution. In particular, NOx emissions from factories, auto mobiles, etc. in urban areas have become worse. To solve these problems on environmental pollution on a global scale, the use of activated charcoal to reduce air pollutants is increasing. However, the capability of wood-based charcoal materials is not yet fully known. The removal of NOx or its conversion into harmless gases such as N{sub 2} should be described. In this study, the adsorption of NO over wood charcoal or metal oxide-dispersed wood charcoal was investigated. In particular, carbonized wood powder of Sugi (Cryptomeria japonica D. Don) was used to study the effectivity of using these materials in adsorbing NOx. Since wood charcoal is chemically stable, metal oxide with the ability of photocatalysis was dispersed into wood charcoal to improve its adsorption and capability to use the light energy effectively.

Ishihara, Shigehisa; Furutsuka, Takeshi [Kyoto Univ. (Japan)

1996-12-31T23:59:59.000Z

298

NANOSTRUCTURED METAL OXIDES FOR ANODES OF LI-ION RECHARGEABLE BATTERIES  

DOE Green Energy (OSTI)

The aligned nanorods of Co{sub 3}O{sub 4} and nanoporous hollow spheres (NHS) of SnO{sub 2} and Mn{sub 2}O{sub 3} were investigated as the anodes for Li-ion rechargeable batteries. The Co{sub 3}O{sub 4} nanorods demonstrated 1433 mAh/g reversible capacity. The NHS of SnO{sub 2} and Mn{sub 2}O{sub 3} delivered 400 mAh/g and 250 mAh/g capacities respectively in multiple galvonastatic discharge-charge cycles. It was found that high capacity of NHS of metal oxides is sustainable attributed to their unique structure that maintains material integrity during cycling. The nanostructured metal oxides exhibit great potential as the new anode materials for Li-ion rechargeable batteries with high energy density, low cost and inherent safety.

Au, M.

2009-12-04T23:59:59.000Z

299

Tubular solid oxide fuel cells with porous metal supports and ceramic interconnections  

DOE Patents (OSTI)

An intermediate temperature solid oxide fuel cell structure capable of operating at from 600.degree. C. to 800.degree. C. having a very thin porous hollow elongated metallic support tube having a thickness from 0.10 mm to 1.0 mm, preferably 0.10 mm to 0.35 mm, a porosity of from 25 vol. % to 50 vol. % and a tensile strength from 700 GPa to 900 GPa, which metallic tube supports a reduced thickness air electrode having a thickness from 0.010 mm to 0.2 mm, a solid oxide electrolyte, a cermet fuel electrode, a ceramic interconnection and an electrically conductive cell to cell contact layer.

Huang, Kevin (Export, PA); Ruka, Roswell J. (Pittsburgh, PA)

2012-05-08T23:59:59.000Z

300

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

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301

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

302

Synthesis and Study of Boron and Antimony Lewis Acids as Small Anion Receptors and Ligands Towards Transition Metals  

E-Print Network (OSTI)

Although fluoride is used at low concentrations in drinking water as a means of promoting dental health, it poses a danger at high exposure levels where it can lead to skeletal fluorosis or other adverse effects. Cyanide is notoriously toxic, and its large scale use in industrial processes warrants the need for close monitoring to remain aware of potential contamination of water sources and other environmental resources. Based on these considerations, it is critical to continue to develop improved methods of monitoring fluoride and cyanide concentrations in water. However, molecular recognition of these anions in water poses considerable challenges. For fluoride, this is due largely to its high hydration enthalpy (?Ho = -504 kJ mol-1), which drastically reduces its reactivity in water. Additionally, the strong basicity of cyanide (pKa of (HCN) = 9.3) may obscure its detection in neutral water due to protonation. In addition to achieving detection of these anions in water, it is most desirable to have information of the detection event relayed in the form of a positive, rather than negative, response (i.e., turn-on vs turn-off). The general strategy of appending cationic groups to triarylboranes imparts beneficial Coulombic, inductive, and sometimes chelate effects that have allowed a number of these Lewis acidic receptors to sense fluoride and cyanide in aqueous environments. With the goal of developing new triarylborane-based receptors that show enhanced affinities for these anions, as well as turn-on responses to detection, a series of pyridinium boranes were synthesized and studied. Having recognized that the inherent Lewis acidity of antimony(V) species might be exploited for anion sensing, we also describe initial studies on the ability of tetraorganostibonium ions (R4Sb+) and cationic transition metal-triarylstibine complexes (R3SbM+) to complex fluoride. Finally, the electropositivity of antimony and its ability to form stable compounds in both the +3 and +5 oxidation states have led us to begin investigations into the bonding and redox reactivity of novel metal stibine/stiborane complexes.

Wade, Casey

2011-12-01T23:59:59.000Z

303

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

Science Conference Proceedings (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

304

Kh a 1,2 hyperesatellites of 3d transition metals and their photoexcitation energy dependence.  

SciTech Connect

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

305

Beyond the Lone-Pair Model for Structurally Distorted Metal Oxides  

NLE Websites -- All DOE Office Websites (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.

306

Beyond the Lone-Pair Model for Structurally Distorted Metal Oxides  

NLE Websites -- All DOE Office Websites (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.

307

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

DOE Green Energy (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

308

Polarization Dependence of L- and M-Edge Resonant Inelastic X-Ray Scattering in Transition-Metal Compounds  

SciTech Connect

The resonant inelastic x-ray scattering (RIXS) cross section at the L and M edges of transition-metal compounds is studied using an effective scattering operator. The intensities of the elastic peak and for spin-flip processes are derived. It is shown how the polarization dependence can be used to select transitions. Comparisons are made with experiment. A detailed analysis of the polarization and angular dependence of L- and M-edge RIXS for divalent copper compounds, such as the high-T{sub c} superconductors, is given.

van Veenendaal, Michel (ANL/NIU)

2010-12-03T23:59:59.000Z

309

Mercury Removal from Aqueous Systems Using Commercial and Laboratory Prepared Metal Oxide Nanoparticles  

E-Print Network (OSTI)

Five commercial metal oxide nanoparticles (CuO, SiO2, Fe2O3, TiO2 and Al2O3) have been individually screened for mercury removal in a batch reactor under bicarbonate buffered and non-buffered aqueous solutions (DI water). Copper oxide was then selected for surface modification to enhance mercury removal. The surfaces of both laboratory prepared and commercially available copper oxide nanoparticles were treated with 1-octanethiol to produce copper sulfide and/or copper alkanethiol nanoparticles. The resulting particles were characterized using X-Ray Fluorescence(XRF), X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The novel nanoparticles demonstrated very high mercury removal (> 99%) from both the buffered and non-buffered aqueous solutions.

Desai, Ishan

2009-08-01T23:59:59.000Z

310

Primary Water SCC Understanding and Characterization Through Fundamental Testing in the Vicinity of the Nickel/Nickel Oxide Phase Transition  

DOE Green Energy (OSTI)

This paper quantifies the nickel alloy stress corrosion crack growth rate (SCCGR) dissolved hydrogen level functionality. SCCGR has been observed to exhibit a maximum in proximity to the nickel/nickel oxide phase transition. The dissolved hydrogen level SCCGR dependency has been quantified in a phenomenological model in terms of the stability of nickel oxide not the dissolved hydrogen level. The observed SCCGR dependency has been extended to lower temperatures through the developed model and Contact Electrical Resistance (CER) measurements of the nickel/nickel oxide phase transition. Understanding obtained from this hydrogen level SCC functionality and complementary SCC subprocesses test results is discussed. Specifically, the possible SCC fundamental subprocesses of corrosion kinetics, hydrogen permeation and pickup have also been measured for nickel alloys. Secondary Ion Mass Spectroscopy (SIMS) analysis has been performed on SCCGR specimens tested in heavy water (D{sub 2}O).

D.S. Morton; S.A. Attanasio; G.A. Young

2001-05-08T23:59:59.000Z

311

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

Science Conference Proceedings (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

312

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

313

Transition metal ion-assisted photochemical generation of alkyl halides and hydrocarbons from carboxylic acids  

Science Conference Proceedings (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

314

WASP-36b: A new transiting planet around a metal-poor G-dwarf, and an analysis of correlated noise in transit light curves  

E-Print Network (OSTI)

We report the discovery, from WASP and CORALIE, of a transiting exoplanet in a 1.54-d orbit. The host star, WASP-36, is a magnitude 12.7, metal-poor G2 dwarf (Teff = 5881 +/- 137 K), with [Fe/H] = -0.31 +/- 0.12. We determine the planet to have mass and radius respectively 2.27 +/- 0.07 and 1.27 +/- 0.03 times that of Jupiter. We have eight partial or complete transit light curves, from four different observatories, which allows us to investigate the extent to which red noise in follow-up light curves affects the fitted system parameters. We find that the solutions obtained by analysing 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.

Smith, A M S; Cameron, A Collier; Gillon, M; Hellier, C; Lendl, M; Maxted, P F L; Queloz, D; Smalley, B; Triaud, A H M J; West, R G; Barros, S C C; Jehin, E; Pepe, F; Pollacco, D; Segransan, D; Southworth, J; Street, R A; Udry, S

2011-01-01T23:59:59.000Z

315

WASP-36b: A NEW TRANSITING PLANET AROUND A METAL-POOR G-DWARF, AND AN INVESTIGATION INTO ANALYSES BASED ON A SINGLE TRANSIT LIGHT CURVE  

SciTech Connect

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 (T{sub eff} = 5959 {+-} 134 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.

Smith, A. M. S.; Anderson, D. R.; Hellier, C.; Maxted, P. F. L.; Smalley, B.; Southworth, J. [Astrophysics Group, Keele University, Staffordshire, ST5 5BG (United Kingdom); Collier Cameron, A. [SUPA, School of Physics and Astronomy, University of St Andrews, North Haugh, Fife, KY16 9SS (United Kingdom); Gillon, M.; Jehin, E. [Institut d'Astrophysique et de Geophysique, Universite de Liege, Allee du 6 Aout, 17 Bat. B5C, Liege 1 (Belgium); Lendl, M.; Queloz, D.; Triaud, A. H. M. J.; Pepe, F.; Segransan, D.; Udry, S. [Observatoire de Geneve, Universite de Geneve, 51 Chemin des Maillettes, 1290 Sauverny (Switzerland); West, R. G. [Department of Physics and Astronomy, University of Leicester, Leicester, LE1 7RH (United Kingdom); Barros, S. C. C.; Pollacco, D. [Astrophysics Research Centre, School of Mathematics and Physics, Queen's University, University Road, Belfast, BT7 1NN (United Kingdom); Street, R. A., E-mail: amss@astro.keele.ac.uk [Las Cumbres Observatory, 6740 Cortona Drive Suite 102, Goleta, CA 93117 (United States)

2012-04-15T23:59:59.000Z

316

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

317

Pre-Oxidized and Nitrided Stainless Steel Foil for Proton Exchange ...  

Science Conference Proceedings (OSTI)

Post-test analyses of the membrane electrode assemblies (MEAs) by x-ray ... Simulation of Oxygen Ion Transport in Mixed-Conducting Solid Oxide Fuel Cell ... Sintering Performance of YSZ Ceramics with Transition Metal Oxide Sintering Aid

318

Transition Metal Catalyzed Hydroarylation of Multiple Bonds: Exploration of Second Generation Ruthenium Catalysts and Extension to Copper Systems  

DOE Green Energy (OSTI)

Catalysts provide foundational technology for the development of new materials and can enhance the efficiency of routes to known materials. New catalyst technologies offer the possibility of reducing energy and raw material consumption as well as enabling chemical processes with a lower environmental impact. The rising demand and expense of fossil resources has strained national and global economies and has increased the importance of accessing more efficient catalytic processes for the conversion of hydrocarbons to useful products. The goals of the research are to develop and understand single-site homogeneous catalysts for the conversion of readily available hydrocarbons into useful materials. A detailed understanding of these catalytic reactions could lead to the development of catalysts with improved activity, longevity and selectivity. Such transformations could reduce the environmental impact of hydrocarbon functionalization, conserve energy and valuable fossil resources and provide new technologies for the production of liquid fuels. This project is a collaborative effort that incorporates both experimental and computational studies to understand the details of transition metal catalyzed C-H activation and C-C bond forming reactions with olefins. Accomplishments of the current funding period include: (1) We have completed and published studies of C-H activation and catalytic olefin hydroarylation by TpRu{l_brace}P(pyr){sub 3}{r_brace}(NCMe)R (pyr = N-pyrrolyl) complexes. While these systems efficiently initiate stoichiometric benzene C-H activation, catalytic olefin hydroarylation is hindered by inhibition of olefin coordination, which is a result of the steric bulk of the P(pyr){sub 3} ligand. (2) We have extended our studies of catalytic olefin hydroarylation by TpRu(L)(NCMe)Ph systems to L = P(OCH{sub 2}){sub 3}CEt. Thus, we have now completed detailed mechanistic studies of four systems with L = CO, PMe{sub 3}, P(pyr){sub 3} and P(OCH{sub 2}){sub 3}CEt, which has provided a comprehensive understanding of the impact of steric and electronic parameters of 'L' on the catalytic hydroarylation of olefins. (3) We have completed and published a detailed mechanistic study of stoichiometric aromatic C-H activation by TpRu(L)(NCMe)Ph (L = CO or PMe{sub 3}). These efforts have probed the impact of functionality para to the site of C-H activation for benzene substrates and have allowed us to develop a detailed model of the transition state for the C-H activation process. These results have led us to conclude that the C-H bond cleavage occurs by a {sigma}-bond metathesis process in which the C-H transfer is best viewed as an intramolecular proton transfer. (4) We have completed studies of Ru complexes possessing the N-heterocyclic carbene IMes (IMes = 1,3-bis-(2,4,6-trimethylphenyl)imidazol-2-ylidene). One of these systems is a unique four-coordinate Ru(II) complex that catalyzes the oxidative hydrophenylation of ethylene (in low yields) to produce styrene and ethane (utilizing ethylene as the hydrogen acceptor) as well as the hydrogenation of olefins, aldehydes and ketones. These results provide a map for the preparation of catalysts that are selective for oxidative olefin hydroarylation. (5) The ability of TpRu(PMe{sub 3})(NCMe)R systems to activate sp{sup 3} C-H bonds has been demonstrated including extension to subsequent C-C bond forming steps. These results open the door to the development of catalysts for the functionalization of more inert C-H bonds. (6) We have discovered that Pt(II) complexes supported by simple nitrogen-based ligands serve as catalysts for the hydroarylation of olefins. Given the extensive studies of Pt-based catalytic C-H activation, we believe these results will provide an entry point into an array of possible catalysts for hydrocarbon functionalization.

T. Brent Gunnoe

2011-02-17T23:59:59.000Z

319

An exploratory program for using hydrous metal oxide ion exchangers as Fischer-Tropsch catalysts  

SciTech Connect

The purpose of this program is to investigate the potential of hydrous metal oxide (HMO) ion exchangers, invented at Sandia National Laboratories, as Fischer-Tropsch (F-T) catalysts. Metals known to be active in F-T synthesis (e.g. Fe, Co) were ion exchanged on hydrous metal oxide supports. Although HMO catalysts based on Zr, Nb, and Ta have been investigated in direct coal liquefaction studies, this effect focused on formulations based on the hydrous titanium oxide (HTO) system. The program has the goals of developing a catalyst with (1) high activity, (2) selectively to fuel range or other useful products, and (3) better properties for use in slurry reactors. The program has three main tasks: (1) catalyst synthesis, to develop methods for preparing catalysts having desirable F-T properties, (2) characterization, to investigate catalysts proving to have desirable properties by a variety of analytical techniques to determine correlations between activity and material properties and (3) testing to determine activity and selectivity of catalysts. This paper discussed results of activity testing of Ruhrchemie catalyst and some catalyst formulations prepared using ion exchange on hydrous titanium oxide and precipitation. For example, at 250{degree}C the Ruhrchemie catalyst converts {approximately}50% of the syngas feed to reaction products. In comparison, iron catalysts prepared by ion exchange and precipitation had conversions ranging from 20 to 50% over a temperature range of 250 to 275{degree}C of the syngas feed. In addition, results are Auger surface analysis of Ruhrchemie catalyst are presented. 6 refs., 2 figs., 2 tabs.

Lynch, A.W.; Dosch, R.G.; Sault, A.G.

1990-01-01T23:59:59.000Z

320

Incorporation of 4d and 5d Transition Metal Cyanometallates into Magnetic Clusters and Materials.  

E-Print Network (OSTI)

The work presented herein describes efforts to synthesize and characterize new types of cyanide-bridged molecular materials encompassing both discrete clusters and extended solids. This investigation focused on the incorporation of anisotropic 4d and 5d transition metal ion building blocks into such materials. In this vein, systematic studies on the magnetic properties of families of these cyano-bridges species were conducted and these new materials represent a new addition to the field of cyanide chemistry incorporating for the first time the hexacyanometallates of [Ru(CN)6]3- and [Os(CN)6]3- into discrete molecules and extended networks. These compounds will serve as models for new theoretical studies in understanding the role of magnetic exchange interactions, both isotropic and anisotropic, in the study of nanomagnetic materials. Results were obtained from using the well known octacyanometallates of MoV and WV as building blocks for the synthesis and the magnetic investigation of both trigonal bipyramidal and pentadecanuclear clusters including the discovery of a new SMM. By expanding the research to previously unused hexacyanometallates, the synthesis and characterization of the first known examples of clusters based on hexacyanoosmate(III) and hexacyanoruthenate(III) building blocks and their use in preparing new theoretical models of magnetic species. A novel pair of clusters is further detailed in the study of the trigonal bipyramidal clusters of [Fe(tmphen)2]3[Os(CN)6]2 and [Fe(tmphen)2]3[Ru(CN)6]2 and an in depth study of the CTIST behavior of these clusters using Mossbauer spectroscopy, variable temperature crystallography, epr, and variable temperature IR measurements. Finally, this work discusses new magnetic Prussian Blue analogs prepared from the hexacyanoosmate(III) and hexacyanoruthenate(III) anions with a comparison to the trigonal bipyramidal clusters presented based on these hexacyanoosmate(III) and hexacyanoruthenate(III) building blocks.

Hilfiger, Matthew Gary

2010-05-01T23:59:59.000Z

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321

Generation, Detection and Characterization of Gas-phase Transition Metal Containing Molecules  

SciTech Connect

The reactive products of laser ablated metals with simple gaseous reagents were characterized using high resolution molecular beam optical spectroscopy.

Timothy C. Steimle

2005-06-28T23:59:59.000Z

322

Solid-State 17O NMR Study of Benzoic Acid Adsorption On Metal Oxide Surfaces  

Science Conference Proceedings (OSTI)

Solid-state 17O NMR spectra of 17O-labeled benzoic and anisic acids are reported and benzoic acid is used to probe the surface of metal oxides. Complexes formed when benzoic acid is dry-mixed with mesoporous silica, and nonporous titania and alumina are characterized. Chemical reactions with silica are not observed. The nature of benzoic acid on silica is a function of the water content of the oxide. The acid disperses in the pores of the silica if the silica is in equilibrium with ambient laboratory humidity. The acid displays high mobility as evidenced by a liquid-like, Lorentzian resonance. Excess benzoic acid remains as the crystalline hydrogen-bonded dimer. Benzoic acid reacts with titania and alumina surfaces in equilibrium with laboratory air to form the corresponding titanium and aluminum benzoates. In both materials the oxygen of the 17O-labeled acid is bound to the metal, showing the reaction proceeds by bond formation between oxygen deficient metal sites and the oxygen of the carboxylic acid. 27Al MAS NMR confirms this mechanism for the reaction on alumina. Dry mixing of benzoic acid with alumina rapidly quenches pentacoordinate aluminum sites, excellent evidence that these sites are confined to the surface of the alumina particles.

Hagaman, Edward {Ed} W [ORNL; Chen, Banghao [ORNL; Jiao, Jian [ORNL; Parsons, Williams [Oak Ridge National Laboratory (ORNL)

2012-01-01T23:59:59.000Z

323

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

DOE Green Energy (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

324

Manganese Doping of Magnetic Iron Oxide Nanoparticles: Tailoring Surface Reactivity for a Regenerable Heavy Metal Sorbent  

SciTech Connect

A method for tuning the analyte affinity of magnetic, inorganic nanostructured sorbents for heavy metal contaminants is described. The manganese-doped iron oxide nanoparticle sorbents have a remarkably high affinity compared to the precursor material. Sorbent affinity can be tuned toward an analyte of interest simply by adjustment of the dopant quantity. The results show that following the Mn doping process there is a large increase in affinity and capacity for heavy metals (i.e., Co, Ni, Zn, As, Ag, Cd, Hg, and Tl). Capacity measurements were carried out for the removal of cadmium from river water and showed significantly higher loading than the relevant commercial sorbents tested for comparison. The reduction in Cd concentration from 100 ppb spiked river water to 1 ppb (less than the EPA drinking water limit of 5 ppb for Cd) was achieved following treatment with the Mn-doped iron oxide nanoparticles. The Mn-doped iron oxide nanoparticles were able to load 1 ppm of Cd followed by complete stripping and recovery of the Cd with a mild acid wash. The Cd loading and stripping is shown to be consistent through multiple cycles with no loss of sorbent performance.

Warner, Cynthia L.; Chouyyok, Wilaiwan; Mackie, Katherine E.; Neiner, Doinita; Saraf, Laxmikant; Droubay, Timothy C.; Warner, Marvin G.; Addleman, Raymond S.

2012-02-28T23:59:59.000Z

325

X-Ray Absorption Studies of Vanadium-Containing Metal Oxide Nanocrystals  

Science Conference Proceedings (OSTI)

Metal oxide nanocrystals offer significant potential for use as catalysts or catalyst supports due to their high surface areas and unique chemical properties that result from the high number of exposed corners and edges. However, little is known about the catalytic activity of these materials, especially as oxidation catalysts. This research focused on the preparation, characterization and use of vanadium-containing nanocrystals as selective oxidation catalysts. Three vanadium-containing nanocrystals were prepared using a modified sol-gel procedure: V/MgO, V/SiO2, and vanadium phosphate (VPO). These represent active oxidation catalysts for a number of industrially relevant reactions. The catalysts were characterized by x-ray diffraction and Raman, UV-VIS, infrared and x-ray absorption spectroscopies with the goal of determining the primary structural and chemical differences between nanocrystals and microcrystals. The catalytic activity of these catalysts was also studied in oxidative dehydrogenation of butane and methanol oxidation to formaldehyde. V/MgO nanocrystals were investigated for activity in oxidative dehydrogenation of butane and compared to conventional V/MgO catalysts. Characterization of V/MgO catalysts using Raman spectroscopy and x-ray absorption spectroscopy showed that both types of catalysts contained magnesium orthovanadate at vanadium loadings below 15 weight%, but above that loading, magnesium pyrovanadate may have been present. In general, MgO nanocrystals had roughly half the crystal size and double the surface area of the conventional MgO. In oxidative dehydrogenation of butane, nanocrystalline V/MgO gave higher selectivity to butene than conventional V/MgO at the same conversion. This difference was attributed to differences in vanadium domain size resulting from the higher surface areas of the nanocrystalline support, since characterization suggested that similar vanadium phases were present on both types of catalysts. Experiments in methanol oxidation were used to probe the chemical differences between sol-gel prepared and conventionally prepared metal oxides. Both V/MgO and V/SiO2 were studied. For both catalysts, similar product selectivities were noted for either preparation method, suggesting similar acid/base and redox properties for the catalysts. At lower weight loadings (butane oxidation to maleic anhydride. In this method vanadium (V) triisopropoxide was reacted with orthophosphoric acid in THF to form a gel. Drying this gel under air resulted in an intercalated VOPO4 compound, where solvent molecules were trapped between layers of the vanadium phosphate compound. Higher surface areas could be achieved by drying this gel at high pressure in an autoclave. The amount of solvent (THF) placed in the autoclave was important in this process. Low amounts of solvent led to a lower surface area, as the solvent evaporated before reaching the critical point and collapsed the gel's pores. In addition, vanadium reduction occurred in the autoclave due to reaction of isopropanol with the vanadium phosphate. Higher amounts of THF reduced the concentration of isopropanol, leading to less reduction. Surfaces areas in excess of 100 m2/g were achieved with this method, and the product was confirmed through XPS and IR to be VOHPO4*0.5H2O, the common precursor for industrial VPO catalysts. Furthermore, this product displayed a platelet morphology, which is desirable for butane oxidation. Further work showed that this material could be transformed to (VO)2P2O7 (the industrial catalyst for butane oxidation to maleic anhydride) by heating under nitrogen without losing much surface are

Hohn, Keith, L.

2006-01-09T23:59:59.000Z

326

Variation of the shape and morphological properties of silica and metal oxide powders by electro homogeneous precipitation  

DOE Patents (OSTI)

The present invention provides a method for preparing irreversible linear aggregates (fibrils) of metal oxide powders by utilizing static or pulsed DC electrical fields across a relatively non-conducting liquid solvent in which organometal compounds or silicon alkoxides have been dissolved. The electric field is applied to the relatively non-conducting solution throughout the particle formation and growth process promoting the formation of either linear aggregates (fibrils) or spherical shaped particles as desired. Thus the present invention provides a physical method for altering the size, shape and porosity of precursor hydrous metal oxide or hydrous silicon oxide powders for the development of advanced ceramics with improved strength and insulating capacity.

Harris, Michael T. (Knoxville, TN); Basaran, Osman A. (Oak Ridge, TN); Sisson, Warren G. (Oak Ridge, TN); Brunson, Ronald R. (Lenoir City, TN)

1997-01-01T23:59:59.000Z

327

Impact of metal nano layer thickness on tunneling oxide and memory performance of core-shell iridium-oxide nanocrystals  

SciTech Connect

The impact of iridium-oxide (IrO{sub x}) nano layer thickness on the tunneling oxide and memory performance of IrO{sub x} metal nanocrystals in an n-Si/SiO{sub 2}/Al{sub 2}O{sub 3}/IrO{sub x}/Al{sub 2}O{sub 3}/IrO{sub x} structure has been investigated. A thinner (1.5 nm) IrO{sub x} nano layer has shown better memory performance than that of a thicker one (2.5 nm). Core-shell IrO{sub x} nanocrystals with a small average diameter of 2.4 nm and a high density of {approx}2 x 10{sup 12}/cm{sup 2} have been observed by scanning transmission electron microscopy. The IrO{sub x} nanocrystals are confirmed by x-ray photoelectron spectroscopy. A large memory window of 3.0 V at a sweeping gate voltage of {+-}5 V and 7.2 V at a sweeping gate voltage of {+-} 8 V has been observed for the 1.5 nm-thick IrO{sub x} nano layer memory capacitors with a small equivalent oxide thickness of 8 nm. The electrons and holes are trapped in the core and annular regions of the IrO{sub x} nanocrystals, respectively, which is explained by Gibbs free energy. High electron and hole-trapping densities are found to be 1.5 x 10{sup 13}/cm{sup 2} and 2 x 10{sup 13}/cm{sup 2}, respectively, due to the small size and high-density of IrO{sub x} nanocrystals. Excellent program/erase endurance of >10{sup 6} cycles and good retention of 10{sup 4} s with a good memory window of >1.2 V under a small operation voltage of {+-} 5 V are obtained. A large memory size of >10 Tbit/sq. in. can be designed by using the IrO{sub x} nanocrystals. This study is not only important for the IrO{sub x} nanocrystal charge-trapping memory investigation but it will also help to design future metal nanocrystal flash memory.

Banerjee, W.; Maikap, S. [Thin Film Nano Tech. Lab., Department of Electronic Engineering, Chang Gung University, Tao-Yuan, Taiwan 333, Taiwan (China); Tien, T.-C. [Material Research Laboratories, Industrial Technology Research Institute, Hsinchu, Taiwan 310, Taiwan (China); Li, W.-C.; Yang, J.-R. [Department of Materials Science and Engineering, National Taiwan University, Taipei 106, Taiwan (China)

2011-10-01T23:59:59.000Z

328

Effect of Temperature on GaGdO/GaN Metal Oxide Semiconductor Field Effect Transistors  

SciTech Connect

GaGdO was deposited on GaN for use as a gate dielectric in order to fabricate a depletion metal oxide semiconductor field effect transistor (MOSFET). This is the fmt demonstration of such a device in the III-Nitride system. Analysis of the effect of temperature on the device shows that gate leakage is significantly reduced at elevated temperature relative to a conventional metal semiconductor field effeet transistor (MESFET) fabricated on the same GaN layer. MOSFET device operation in fact improved upon heating to 400 C. Modeling of the effeet of temperature on contact resistance suggests that the improvement is due to a reduction in the parasitic resistances present in the device.

Abernathy, C.R.; Baca, A.; Chu, S.N.G.; Hong, M.; Lothian, J.R.; Marcus, M.A.; Pearton, S.J.; Ren, F.; Schurman, M.J.

1998-10-14T23:59:59.000Z

329

Low temperature photochemical vapor deposition of alloy and mixed metal oxide films  

DOE Patents (OSTI)

Method and apparatus for formation of an alloy thin film, or a mixed metal oxide thin film, on a substrate at relatively low temperatures. Precursor vapor(s) containing the desired thin film constituents is positioned adjacent to the substrate and irradiated by light having wavelengths in a selected wavelength range, to dissociate the gas(es) and provide atoms or molecules containing only the desired constituents. These gases then deposit at relatively low temperatures as a thin film on the substrate. The precursor vapor(s) is formed by vaporization of one or more precursor materials, where the vaporization temperature(s) is selected to control the ratio of concentration of metals present in the precursor vapor(s) and/or the total precursor vapor pressure.

Liu, David K. (San Pablo, CA)

1992-01-01T23:59:59.000Z

330

Post-Deposition Induced Conductivity in Pulsed Laser Irradiated Metal Doped Zinc Oxide Films  

DOE Green Energy (OSTI)

The optical and electrical properties of doped solution-deposited and rf sputter-deposited thin metal oxide films were investigated following post deposition pulsed laser irradiation. Solution deposited films were annealed at 450 ºC. Following the heating regiment, the transparent metal oxide films were subjected to 355 nm pulsed Nd:YAG laser irradiation (4 nsec pulsewidth) at fluences between 5 and 150 mJ/cm2. Irradiation times at pulse frequencies of 30 Hz ranged from seconds to tens of minutes. Film densification, index change and a marked increase in conductivity were observed following irradiation in air and under vacuum of Al:ZnO (AZO), Ga:ZnO (GZO), and In:ZnO (IZO) films deposited on silica substrates. Despite the measured increase in conductivity, all films continued to show high transparency on the order of 90% at wavelengths from the band edge well into the near infrared region of the spectrum. Laser energies required for turning on the conductivity of these films varied depending upon the dopant. Irradiations in air yielded resistivity measurements on the order of 16 ?.cm. Resistivities of films irradiated under vacuum were on the order of 0.1 ?.cm. The increase in conductivity can be attributed to the formation of oxygen vacancies and subsequent promotion of free carriers into the conduction band. All irradiated films become insulating after around 24 hours. Oxygen atoms in air become reduced by electrons in the metal conduction band and diffuse into the vacancies in the lattice. The rate of this reduction process depends on the type of dopant. This work also sheds light on the damage threshold, correlating the optical properties with the presence of free carriers that have been introduced into the conduction band. All films were characterized by means of UV-VIS-NIR transmission spectroscopy, visible and UV Raman spectroscopy and Hall measurements. Analysis of interference fringes in measured transmission spectra allowed film density and refractive index to be evaluated while the Raman measurements showed an increase in LO mode intensity with respect to the TO mode intensity as the films became more conducting. Results of this study are not only important for the continued development of transparent conducting oxide films that find use in photovoltaic cells and solid state lighting modules, but also provide evidence for the role of free carriers in initiating the laser damage process in these wide bandgap metal oxide films.

Wang, Lisa J.; Exarhos, Gregory J.

2009-12-03T23:59:59.000Z

331

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

DOE Green Energy (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

332

Rapid thermal cycling of metal-supported solid oxide fuel cellmembranes  

DOE Green Energy (OSTI)

Solid oxide fuel cell (SOFC) membranes were developed in which zirconia-based electrolyte thin films were supported by a composite metal/ceramic electrode, and were subjected to rapid thermal cycling between 200 and 800 C. The effects of this cycling on membrane performance were evaluated. The membranes, not yet optimized for performance, showed a peak power density of 350mW/cm2at 900 C in laboratory-sized SOFCs that was not affected by the thermal cycling. This resistance to cycling degradation is attributed to the close matching of thermal expansion coefficient of the cermet support electrode with that of the zirconia electrolyte.

Matus, Yuriy B.; De Jonghe, Lutgard C.; Jacobson, Craig P.; Visco, Steven J.

2004-01-02T23:59:59.000Z

333

A New In Situ Method of Determining Relative Abundances and Charge States of Implanted Transition Metals in Individual Grains Using Synchrotron X-Ray Fluorescence  

SciTech Connect

We report on a new in situ method of determining relative abundances and charge states of implanted transition metals in individual grains using synchrotron X-ray fluorescence. In order to determine in situ the relative abundances and charge states of the transition metals in implanted solar wind in individual lunar plagioclase grains, we have developed a new microbeam x-ray fluorescence method using the synchrotron x-ray microprobe at the Advanced Photon Source (GSECARS sector 13) at Argonne National Laboratory.

Kitts, K.; Sutton, S.; Newville, M. (NIU); (UofC)

2007-03-06T23:59:59.000Z

334

Impact of Iron-Reducing Bacteria on Metals and Radionuclides Adsorbed to Humic-Coated Iron(III) Oxides  

Science Conference Proceedings (OSTI)

This is the final report for Grant No. DEFGO2-98ER62691 submitted to the DOE NABR Program. This research has focused on (1) the role of natural organic matter (NOM), quinines, and complexants in enhancing the biological reduction of solid-phase crystalline ferric oxides, (2) the effect of heavy metals (specifically zinc) and NOM on ferric oxide bioreduction, (3) the sorption of Me(II) [Cu(II), Fe(II), Mn(II) and Zn(II)] to ferric oxides and subsequent Me(II)-promoted phase transformations of the ferric oxides, and (4) the development of reaction-based biogeochemical models to numerically simulate our experimental results.

Burgos, W. D.

2005-02-01T23:59:59.000Z

335

Periodic Properties of Force Constants of Small Transition-Metal and Lanthanide Clusters  

E-Print Network (OSTI)

(CASI), The City College of New York, Convent Ave. at 138th Street, New York, New York 10031 Received from the extensive knowledge we have about the physical properties of both atoms and metallic crystals. The relationship between atomic and metallic properties can be probed by following the attributes of clusters

Lombardi, John R.

336

Aqueous-phase hydrogenation of acetic acid over transition metal catalysts  

SciTech Connect

Catalytic hydrogenation of acetic acid to ethanol has been carried out in aqueous phase on several metals, with ruthenium being the most active and selective. DFT calculations suggest that the initial CO bond scission yielding acetyl is the key step and that the intrinsic reactivity of the metals accounts for the observed activity.

Olcay, Hakan [University of Massachusetts, Amherst; Xu, Lijun [ORNL; Xu, Ye [ORNL; Huber, George [University of Massachusetts, Amherst

2010-01-01T23:59:59.000Z

337

Air-Oxidation of a (Zr55Cu30Al10Ni5)98Er2 Bulk Metallic Glass at ...  

Science Conference Proceedings (OSTI)

About this Abstract. Meeting, 2010 TMS Annual Meeting & Exhibition. Symposium , Bulk Metallic Glasses VII. Presentation Title, Air-Oxidation of a ...

338

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

339

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

340

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  

Science Conference Proceedings (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

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

Metal-insulator transition by isovalent anion substitution in Ga1-xMnxAs: Implications to ferromagnetism  

SciTech Connect

We have investigated the effect of partial isovalent anion substitution in Ga1-xMnxAs on electrical transport and ferromagnetism. Substitution of only 2.4percent of As by P induces a metal-insulator transition at a constant Mn doping of x=0.046 while the replacement of 0.4 percent As with N results in the crossover from metal to insulator for x=0.037. This remarkable behavior is consistent with a scenario in which holes located within an impurity band are scattered by alloy disorder in the anion sublattice. The shorter mean free path of holes, which mediate ferromagnetism, reduces the Curie temperature TC from 113 K to 60 K (100 K to 65 K) upon the introduction of 3.1 percent P (1percent N) into the As sublattice.

Stone, P.R.; Alberi, K.; Tardif, S.K.Z.; Beeman, J.W.; Yu, K.M.; Walukiewicz, W.; Dubon, O.D.

2008-02-07T23:59:59.000Z

342

Trends in Methanol Decomposition on Transition Metal Alloy Clusters from Scaling and Brønsted–Evans–Polanyi Relationships  

Science Conference Proceedings (OSTI)

A combination of ?rst principles Density Functional Theory calculations and thermochemical scaling relationships are employed to estimate the thermochemistry and kinetics of methanol decomposition on unsupported subnanometer metal clusters. The approach uses binding energies of various atomic and molecular species, determined on the pure metal clusters, to develop scaling relationships that are then further used to estimate the methanol decomposition thermodynamics for a series of pure and bimetallic clusters with four atoms per cluster. Additionally, activation energy barriers are estimated from Brønsted–Evans–Polanyi plots relating transition and ?nal state energies on these clusters. The energetic results are combined with a simple, microkineticallyinspired rate expression to estimate reaction rates as a function of important catalytic descriptors, including the carbon and atomic oxygen binding energies to the clusters. Based on these analyses, several alloy clusters are identi?ed as promising candidates for the methanol decomposition reaction.

Mehmood, Faisal; Rankin, Rees B.; Greeley, Jeffrey P.; Curtiss, Larry A.

2012-05-15T23:59:59.000Z

343

Disposition of Uranium -233 (sup 233U) in Plutonium Metal and Oxide at the Rocky Flats Environmental Technology Site  

Science Conference Proceedings (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

344

Process for improving metal production in steelmaking processes  

DOE Patents (OSTI)

A process and apparatus for improving metal production in ironmaking and steelmaking processes is disclosed. The use of an inert metallic conductor in the slag containing crucible and the addition of a transition metal oxide to the slag are the disclosed process improvements.

Pal, Uday B. (Malden, MA); Gazula, Gopala K. M. (Somerville, MA); Hasham, Ali (Karachi, PK)

1996-01-01T23:59:59.000Z

345

Process for improving metal production in steelmaking processes  

DOE Patents (OSTI)

A process and apparatus for improving metal production in ironmaking and steelmaking processes is disclosed. The use of an inert metallic conductor in the slag containing crucible and the addition of a transition metal oxide to the slag are the disclosed process improvements. 6 figs.

Pal, U.B.; Gazula, G.K.M.; Hasham, A.

1996-06-18T23:59:59.000Z

346

Interfacial transition regions at germanium/Hf oxide based dielectric interfaces: Qualitative differences between non-crystalline Hf Si oxynitride and nanocrystalline HfO2 gate stacks  

Science Conference Proceedings (OSTI)

The contribution from a relatively low-K SiON (K~6) interfacial transition region (ITR) between Si and transition metal high-K gate dielectrics such as nanocrystalline HfO"2 (K~20), and non-crystalline Hf Si oxynitride (K~10-12) places a significant ... Keywords: Di-vacancy defects, Ge substrates, High-K gate dielectrics, Interfacial transition regions, MOS devices, Native Ge dielectrics, Spectroscopic ellipsometry, X-ray absorption spectroscopy

G. Lucovsky; S. Lee; J. P. Long; H. Seo; J. Lüning

2009-03-01T23:59:59.000Z

347

Evidence of a transition to reorientational disorder in the cubic alkali-metal dodecahydro-closo-dodecaborates  

Science Conference Proceedings (OSTI)

A neutron powder diffraction and differential scanning calorimetry (DSC) study indicates that Cs{sub 2}B{sub 12}H{sub 12} undergoes a second-order phase transition near 529 K that can be described as a reorientational disordering of the B{sub 12}H{sub 12}{sup 2-} icosahedral anions between two lowest-energy configurations within the cubic structure. Such a disordering requires the addition of another mirror plane to the low-temperature Fm3-bar structural symmetry to become Fm3-bar m. Differential scanning calorimetry measurements suggest the possible persistence of some short-range anion order at and above the transition. Additional DSC measurements of the lighter alkali-metal cubic isomorphs, Rb{sub 2}B{sub 12}H{sub 12} and K{sub 2}B{sub 12}H{sub 12}, also indicate second-order transitions for these compounds near 742 K and 811 K, respectively. These results are suggestive of similar order-disorder phase changes as for Cs{sub 2}B{sub 12}H{sub 12}, although confirmation of their existence requires analogous diffraction measurements. - Graphical Abstract: Cs{sub 2}B{sub 12}H{sub 12} undergoes an order-disorder phase transition near 529 K. Similar transitions are observed for K{sub 2}B{sub 12}H{sub 12} and Rb{sub 2}B{sub 12}H{sub 12}. Highlights: > Diffraction and DSC reveal that Cs{sub 2}B{sub 12}H{sub 12} undergoes a 2nd-order phase transition near 529 K. > This phase transition is from the low-temperature Fm3-bar symmetry to Fm3-bar m at high temperatures. > DSC of Rb{sub 2}B{sub 12}H{sub 12} and K{sub 2}B{sub 12}H{sub 12} indicate 2nd-order transitions near 742 K and 811 K, respectively.

Verdal, Nina, E-mail: nina.verdal@nist.gov [NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899-6102 (United States); Wu, Hui [NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899-6102 (United States); Department of Materials Science and Engineering, University of Maryland, College Park, MD 20742-2115 (United States); Udovic, Terrence J. [NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899-6102 (United States); Stavila, Vitalie [Sandia National Laboratories, Livermore, CA 94551-0969 (United States); Zhou Wei; Rush, John J. [NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899-6102 (United States); Department of Materials Science and Engineering, University of Maryland, College Park, MD 20742-2115 (United States)

2011-11-15T23:59:59.000Z

348

X-Ray Absorption Studies of Vanadium-Containing Metal Oxide Nanocrystals  

SciTech Connect

Metal oxide nanocrystals offer significant potential for use as catalysts or catalyst supports due to their high surface areas and unique chemical properties that result from the high number of exposed corners and edges. However, little is known about the catalytic activity of these materials, especially as oxidation catalysts. This research focused on the preparation, characterization and use of vanadium-containing nanocrystals as selective oxidation catalysts. Three vanadium-containing nanocrystals were prepared using a modified sol-gel procedure: V/MgO, V/SiO2, and vanadium phosphate (VPO). These represent active oxidation catalysts for a number of industrially relevant reactions. The catalysts were characterized by x-ray diffraction and Raman, UV-VIS, infrared and x-ray absorption spectroscopies with the goal of determining the primary structural and chemical differences between nanocrystals and microcrystals. The catalytic activity of these catalysts was also studied in oxidative dehydrogenation of butane and methanol oxidation to formaldehyde. V/MgO nanocrystals were investigated for activity in oxidative dehydrogenation of butane and compared to conventional V/MgO catalysts. Characterization of V/MgO catalysts using Raman spectroscopy and x-ray absorption spectroscopy showed that both types of catalysts contained magnesium orthovanadate at vanadium loadings below 15 weight%, but above that loading, magnesium pyrovanadate may have been present. In general, MgO nanocrystals had roughly half the crystal size and double the surface area of the conventional MgO. In oxidative dehydrogenation of butane, nanocrystalline V/MgO gave higher selectivity to butene than conventional V/MgO at the same conversion. This difference was attributed to differences in vanadium domain size resulting from the higher surface areas of the nanocrystalline support, since characterization suggested that similar vanadium phases were present on both types of catalysts. Experiments in methanol oxidation were used to probe the chemical differences between sol-gel prepared and conventionally prepared metal oxides. Both V/MgO and V/SiO2 were studied. For both catalysts, similar product selectivities were noted for either preparation method, suggesting similar acid/base and redox properties for the catalysts. At lower weight loadings (<5%), activity was also similar, but at higher weight loadings the sol-gel prepared catalysts were more active. This was attributed to the greater dispersion of vanadium on sol-gel prepared catalysts, and it was suggested that small vanadium oxide domains were more active in methanol oxidation than polymeric and bulk domains. A novel sol-gel method was developed for preparation of VPO catalysts, which are used industrially in butane oxidation to maleic anhydride. In this method vanadium (V) triisopropoxide was reacted with orthophosphoric acid in THF to form a gel. Drying this gel under air resulted in an intercalated VOPO4 compound, where solvent molecules were trapped between layers of the vanadium phosphate compound. Higher surface areas could be achieved by drying this gel at high pressure in an autoclave. The amount of solvent (THF) placed in the autoclave was important in this process. Low amounts of solvent led to a lower surface area, as the solvent evaporated before reaching the critical point and collapsed the gel's pores. In addition, vanadium reduction occurred in the autoclave due to reaction of isopropanol with the vanadium phosphate. Higher amounts of THF reduced the concentration of isopropanol, leading to less reduction. Surfaces areas in excess of 100 m2/g were achieved with this method, and the product was confirmed through XPS and IR to be VOHPO4*0.5H2O, the common precursor for industrial VPO catalysts. Furthermore, this product displayed a platelet morphology, which is desirable for butane oxidation. Further work showed that this material could be transformed to (VO)2P2O7 (the industrial catalyst for butane oxidation to maleic anhydride) by heating under nitrogen without losing much surface are

Hohn, Keith, L.

2006-01-09T23:59:59.000Z

349

Process for making whiskers, fibers and flakes of transition metal compounds  

DOE Patents (OSTI)

A process for making titanium and chromium nitrides of known morphology by reacting potassium titanate and chromium oxide in the gas phase with NH.sub.3. The products exhibit the same morphology as the starting material.

Bamberger, Carlos E. (Oak Ridge, TN)

1992-01-01T23:59:59.000Z

350

A New Route to Nanoscale Conducting Channels in Insulating Oxides  

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

scale is comparable to the electron wavelength). A multi-orbital two-dimensional electron gas created at the surface of transition-metal oxides, such as SrTiO3 and KTaO3, upon...

351

MEAM with Charge Transfer for TM Oxide Modeling  

Science Conference Proceedings (OSTI)

Abstract Scope, Transition metal (TM) oxides are important material with diverse applications including ... Density functional theory (DFT) modeling studies have provided useful bulk ... Atomistic Modeling of Radiation Damage in bcc Uranium.

352

Engineering Escherichia coli for molecularly defined electron transfer to metal oxides and electrodes  

E-Print Network (OSTI)

1-thiogalactopyranoside Indium tin oxide Microbial fuel cellone type of electrode: indium tin oxide (ITO) coated glasssurface, specifically indium tin oxide (ITO), with nanoscale

Jensen, Heather Marie

2013-01-01T23:59:59.000Z

353

Transition-metal oxides, sulphide and sulphur composites for lithium batteries.  

E-Print Network (OSTI)

??Lithium batteries are important energy storage systems and can make energy storage and usage more efficient than with previous solutions. Moreover, among the lithium batteries,… (more)

Lu, Lin

2012-01-01T23:59:59.000Z

354

Synthesis and characterization of nanostructured transition metal oxides for energy storage devices  

E-Print Network (OSTI)

finding a promising supercapacitor material, (2) developingbeen applied to supercapacitor materials, even though it has

Kim, Jong Woung

2012-01-01T23:59:59.000Z

355

Synthesis and characterization of nanostructured transition metal oxides for energy storage devices  

E-Print Network (OSTI)

Figure 1.1. Ragone plot of various energy storage systems [in technology and energy storage has become the limitingthe limit of commercial energy storage technology comprised

Kim, Jong Woung

2012-01-01T23:59:59.000Z

356

Role of Subsurface Oxygen in Oxide Formation at Transition Metal Surfaces M. Todorova,1  

E-Print Network (OSTI)

:69 AA, Ewf max ¼ 17 Ry, Epot max ¼ 169 Ry, lwf max ¼ 12, lpot max ¼ 4, 19 k- points in the irreducible

Li, Weixue

357

Synthesis and characterization of nanostructured transition metal oxides for energy storage devices  

E-Print Network (OSTI)

Wang, H. Zhou, Angewandte Chemie International Edition 2008,K. Müllen, Angewandte Chemie International Edition W. -M.F. Schulte, Angewandte Chemie International Edition in

Kim, Jong Woung

2012-01-01T23:59:59.000Z

358

Improved layered mixed transition metal oxides for Li-ion batteries  

E-Print Network (OSTI)

Radiation Lightsource (SSRL). We would like to acknowledgeMèhta for the work done at SSRL. REFERENCES [I] Yabuuchi,

Doeff, Marca M.

2010-01-01T23:59:59.000Z

359

Improved layered mixed transition metal oxides for Li-ion batteries  

E-Print Network (OSTI)

vehicles (EV), plug-in hybrid electric vehicles (PHEVs),or hybrid electric vehicles (HEVs). To reduce materialsapplications (plug-in hybrid electric vehicles (PHEVs) and

Doeff, Marca M.

2010-01-01T23:59:59.000Z

360

Sub-Nanostructured Non Transition Metal Complex Grids for Hydrogen Storage  

DOE Green Energy (OSTI)

This project involved growing sub-nanostructured metal grids to increase dynamic hydrogen storage capacity of metal hydride systems. The nano particles of any material have unique properties unlike its bulk form. Nano-structuring metal hydride materials can result in: {sm_bullet}Increased hydrogen molecule dissociation rate, {sm_bullet} Increased hydrogen atom transport rate, {sm_bullet} Decreased decrepitation caused by cycling, {sm_bullet} Increased energy transfer in the metal matrix, {sm_bullet} Possible additional contribution by physical adsorption, and {sm_bullet} Possible additional contribution by quantum effects The project succeeded in making nano-structured palladium using electrochemical growth in templates including zeolites, mesoporous silica, polycarbonate films and anodized alumina. Other metals were used to fine-tune the synthesis procedures. Palladium was chosen to demonstrate the effects of nano-structuring since its bulk hydrogen storage capacity and kinetics are well known. Reduced project funding was not sufficient for complete characterization of these materials for hydrogen storage application. The project team intends to seek further funding in the future to complete the characterization of these materials for hydrogen storage.

Dr. Orhan Talu; Dr. Surendra N. Tewari

2007-10-27T23:59:59.000Z

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

Method for producing metal oxide aerogels having densities less than 0. 02 g/cc  

DOE Patents (OSTI)

A two-step method is described for making transparent aerogels which have a density of less than 0.003 g/cm[sup 3] to those with a density of more than 0.8 g/cm[sup 3], by a sol/gel process and supercritical extraction. Condensed metal oxide intermediate made with purified reagents can be diluted to produce stable aerogels with a density of less than 0.02 g/cm[sup 3]. High temperature, direct supercritical extraction of the liquid phase of the gel produces hydrophobic aerogels which are stable at atmospheric moisture conditions. Monolithic, homogeneous silica aerogels with a density of less than 0.02 to higher than 0.8 g/cm[sup 3], with high thermal insulation capacity, improved mechanical strength and good optical transparency, are described. 7 figures.

Tillotson, T.M.; Poco, J.F.; Hrubesh, L.W.; Thomas, I.M.

1994-01-04T23:59:59.000Z

362

Method for producing metal oxide aerogels having densities less than 0.02 g/cc  

Science Conference Proceedings (OSTI)

A two-step method is described for making transparent aerogels which have a density of less than 0.003 g/cm.sup.3 to those with a density of more than 0.8 g/cm.sup.3, by a sol/gel process and supercritical extraction. Condensed metal oxide intermediate made with purified reagents can be diluted to produce stable aerogels with a density of less than 0.02 g/cm.sup.3. High temperature, direct supercritical extraction of the liquid phase of the gel produces hydrophobic aerogels which are stable at atmospheric moisture conditions. Monolithic, homogeneous silica aerogels with a density of less than 0.02 to higher than 0.8 g/cm.sup.3, with high thermal insulation capacity, improved mechanical strength and good optical transparency, are described.

Tillotson, Thomas M. (Tracy, CA); Poco, John F. (Livermore, CA); Hrubesh, Lawrence W. (Pleasanton, CA); Thomas, Ian M. (Livermore, CA)

1994-01-01T23:59:59.000Z

363

HEU to LEU conversion and blending facility: Metal blending alternative to produce LEU oxide for disposal  

SciTech Connect

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.

1995-09-01T23:59:59.000Z

364

Corrosion and Protection of Metallic Interconnects in Solid Oxide Fuel Cells  

SciTech Connect

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

365

Modeling Ethanol Decomposition on Transition Metals: A Combined Application of Scaling and Brønsted-Evans-Polanyi Relations  

SciTech Connect

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

366

Synthesis, reactivity, and coordination chemistry relevant to the copolymerization of CO2 and epoxides by first row transition metal schiff base complexes  

E-Print Network (OSTI)

Excepting agricultural based products, which themselves require a great deal of energy to produce, our supply of natural resources such as minerals, metal ore, fresh water, coal, oil and natural gas are all limited in supply. The depletion of these substances is imminent and this knowledge weighs heavily on humankind. The utilization of CO2 for the production of polycarbonates is one attempt at exploiting a profoundly abundant and renewable resource. The importance of research in this and similar fields justifies the detailed study of the chemicals and procedures involved with this chemistry. This current work concentrates on the fundamental study of transition metal Schiff base complexes that have shown a great deal of promise in their ability to catalyze the copolymerization of CO2 and epoxide to form aliphatic polycarbonates. A new chromium(III) Schiff base complex has been synthesized and evaluated for its ability to catalyze the formation of polymer. The ligand employed bears an N2O2 coordination sphere identical to the widely utilized chromium(III) and cobalt(III) salen catalysts. This complex was shown to be active towards the copolymerization of CO2 and cyclohexene oxide. Although the activity was less than that seen with chromium(III) salen complex, the study demonstrates that new ligand systems are available beyond salen and deserve further attention. A class of manganese(III) Schiff base complexes was also synthesized and evaluated as catalysts. Although crystallographic data has shown that these complexes are structural analogs to chromium(III) salens, the difference in metal center leads to a nearly complete elimination of catalytic activity. Such a marked difference has been taken advantage of by using this very low activity to study the ring-opening of epoxide in the initial step of the copolymerization both mechanistically and kinetically. It has also been utilized in an evaluation of the coordination chemistry of the polymerization process. This has led to some valuable conclusions about the nature and role of the metal center that previously have not been studied. Manganese(III) salen complexes were also synthesized and evaluated in an effort to compare these important ligands to other Schiff bases and confirm the findings mentioned above.

Frantz, Eric Benjamin

2008-08-01T23:59:59.000Z

367

Investigating the First-Cycle Irreversibility of Lithium Metal Oxide Cathodes for Li Batteries  

DOE Green Energy (OSTI)

Layered lithium metal oxide cathodes typically exhibit irreversibility during the first cycle in lithium cells when cycled in conventional voltage ranges (e.g., 3-4.3 V vs. Li+/Li). In this work, we have studied the first-cycle irreversibility of lithium cells containing various layered cathode materials using galvanostatic cycling and in situ synchrotron X-ray diffraction. When cycled between 3.0 and 4.3 V vs. Li+/Li, the cells containing LiCoO2, LiNi0.8Co0.15Al0.05O2, and Li1.048(Ni1/3Co1/3Mn1/3)0.952O2 as cathodes showed initial coulombic efficiencies of 98.0, 87.0, and 88.6%, respectively, at relatively slow current (8 mA/g). However, the 'lost capacity' could be completely recovered by discharging the cells to low voltages (<2 V vs Li+/Li). During this deep discharge, the same cells exhibited voltage plateaus at 1.17, 1.81, and 1.47 V, respectively, which is believed to be associated with formation of a Li2MO2-like phase (M = Ni, Co, Mn) on the oxide particle surface due to very sluggish lithium diffusion in LieMO2 with {var_epsilon}{yields} 1 (i.e., near the end of discharge). The voltage relaxation curve and in situ X-ray diffraction patterns, obtained from a Li/Li1.048(Ni1/3Co1/3Mn1/3)0.952O2 cell, showed that the oxide cathode reversibly returned to its original state [i.e., Li1.048(Ni1/3Co1/3Mn1/3)0.952O2] during relaxation following the deep discharge to achieve 100% cycle efficiency.

Kang,S.; Yoon , W.; Nam, K.; Yang, X.; Abraham, D.

2008-01-01T23:59:59.000Z

368

INFLUENCE OF OXIDE GROWTH AND METAL CREEP ON STRAIN DEVELOPMENT IN THE STEAM-SIDE OXIDE IN BOILER TUBES  

SciTech Connect

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

369

Relationship between the shear viscosity and heating rate in metallic glasses below the glass transition  

Science Conference Proceedings (OSTI)

It has been shown that first-order irreversible structural relaxation with distributed activation energies must lead to a linear decrease of the logarithm of Newtonian shear viscosity with the logarithm of heating rate upon linear heating of glass. Such a behavior is indeed observed in the experiments on metallic glasses. Structural relaxation-induced viscous flow leads to infra-low-frequency Maxwell viscoelastic internal friction, which is predicted to increase with the heating rate.

Khonik, Vitaly A.; Kobelev, N. P. [Department of General Physics, State Pedagogical University, Lenin Street 86, 394043 Voronezh (Russian Federation); Institute for Solid State Physics, Chernogolovka, 142432 Moscow District (Russian Federation)

2008-04-01T23:59:59.000Z

370

Published on Web 10/28/2008 Gas-Phase, Bulk Production of Metal Oxide Nanowires and Nanoparticles Using a Microwave Plasma Jet Reactor  

E-Print Network (OSTI)

We report gas-phase production of metal oxide nanowires (NWs) and nanoparticles (NPs) using direct oxidation of micron-size metal particles in a high-throughput, atmospheric pressure microwave plasma jet reactor. We demonstrate the concept with production of SnO2, ZnO, TiO2, and Al2O3 NWs. The results suggest that the NW production primarily depends upon the starting metal particle size, microwave power, and the gas-phase composition. The resulting NW powders could be separated from the unreacted metal and metal oxide NPs by sonication in 1-methoxy 2-propanol followed by gravity sedimentation. The experiments conducted using higher microwave powers resulted in spherical, unagglomerated, metal oxide NPs. The results obtained using various metal oxides suggest that the mechanism of NW nucleation and growth in the gas phase is similar to that observed in experiments with metal particles supported on substrates. A simplified analysis suggests that the metal powders melt in the plasma primarily with the heat generated from chemical reactions, such as radical recombination and oxidation reactions on the particle surface.

Jeong H. Kim; Rashekhar Pendyala; Boris Chernomordik; Mahendra K. Sunkara

2008-01-01T23:59:59.000Z

371

Hydrogen incorporation induced metal-semiconductor transition in ZnO:H thin films sputtered at room temperature  

Science Conference Proceedings (OSTI)

The room temperature deposited ZnO:H thin films having high conductivity of 500 Ohm-Sign {sup -1} cm{sup -1} and carrier concentration reaching 1.23 Multiplication-Sign 10{sup 20} cm{sup -3} were reactively sputter deposited on glass substrates in the presence of O{sub 2} and 5% H{sub 2} in Ar. A metal-semiconductor transition at 165 K is induced by the increasing hydrogen incorporation in the films. Hydrogen forms shallow donor complex with activation energy of {approx}10-20 meV at oxygen vacancies (V{sub O}) leading to increase in carrier concentration. Hydrogen also passivates V{sub O} and V{sub Zn} causing {approx}4 times enhancement of mobility to 25.4 cm{sup 2}/V s. These films have potential for use in transparent flexible electronics.

Singh, Anil; Chaudhary, Sujeet; Pandya, D. K. [Thin Film Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi 110016 (India)] [Thin Film Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi 110016 (India)

2013-04-29T23:59:59.000Z

372

Calculations of resistivity and superconducting T/sub c/ in transition metals  

Science Conference Proceedings (OSTI)

A survey is given of various electron-phonon effects which have been calculated for the metals Nb, Mo, Ta, Pd, and Cu. These effects include the mass enhancement lambda, superconducting T/sub c/, electrical and thermal resistivity, Hall coefficient, magnetoresistance, and the successfully tested predictions of linewidths ..gamma../sub 0/ of phonons. The calculations use local density approximations (LDA) energy bands, experimental phonons, and the rigid muffin tin (RMT) approximation. Mesh size noise is less than 1% and the Bloch-Boltzmann integral equation has been solved to unprecedented accuracy.

Allen, P.B.; Beaulac, T.P.; Khan, F.S.; Butler, W.H.; Pinski, F.J.; Swihart, J.C.

1985-01-01T23:59:59.000Z

373

Fully Integrated Complementary Metal Oxide Semiconductor (CMOS) Bio-Assay Platform  

E-Print Network (OSTI)

Oxide Semiconductor (CMOS) Bio-Assay Platform by OctavianOxide Semiconductor (CMOS) Bio-Assay Platform by OctavianOxide Semiconductor (CMOS) Bio-Assay Platform by Octavian

Florescu, Octavian

2010-01-01T23:59:59.000Z

374

Rapid thermal cycling of metal-supported solid oxide fuel cell membranes  

E-Print Network (OSTI)

effect of pressure on solid oxide fuel cell performance," inflat plate solid oxide fuel cells," in Proceedings of theSymposium 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

375

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

DOE Green Energy (OSTI)

Several different catalytic reactions must be carried out in order to convert hydrocarbons (or alcohols) into hydrogen for use as a fuel for polyelectrolyte membrane (PEM) fuel cells. Each reaction in the fuel-processing sequence has a different set of characteristics, which influences the type of catalyst support that should be used for that particular reaction. A wide range of supports are being evaluated for the various reactions in the fuel-processing scheme, including porous and non-porous particles, ceramic and metal straight-channel monoliths, and ceramic and metal monolithic foams. These different types of support have distinctly different transport characteristics. The best choice of support for a given reaction will depend on the design constraints for the system, e.g., allowable pressure drop, and on the characteristics of the reaction for which the catalyst is being designed. Three of the most important reaction characteristics are the intrinsic reaction rate, the exothermicity/endothermicity of the reaction, and the nature of the reaction network, e.g., whether more than one reaction takes place and, in the case of multiple reactions, the configuration of the network. Isotopic transient kinetic analysis was used to study the surface intermediates. The preferential oxidation of low concentrations of carbon monoxide in the presence of high concentrations of hydrogen (PROX) is an important final step in most fuel processor designs. Data on the behavior of straight-channel monoliths and foam monolith supports will be presented to illustrate some of the factors involved in choosing a support for this reaction.

Mr. Paul Chin; Dr. Xiaolei Sun; Professor George W. Roberts; Professor James J. Spivey; Mr. Amornmart Sirijarhuphan; Dr. James G. Goodwin, Jr.; Dr. Richard W. Rice

2002-12-31T23:59:59.000Z

376

Electronic Spin Transition in Nano-size Stoichiometric Lithium Cobalt Oxide  

E-Print Network (OSTI)

A change in the electronic spin state of the surfaces relevant to Li (de)intercalation of nanosized stoichiometric lithium cobalt oxide LiCo(III)O[subscript 2] from low-spin to intermediate and high spin is observed for ...

Qian, Danna

377

NMR Study of the Magnetic and Metal-Insulator Transitions in Na0:5CoO2: A Nesting Scenario J. Bobroff,1  

E-Print Network (OSTI)

NMR Study of the Magnetic and Metal-Insulator Transitions in Na0:5CoO2: A Nesting Scenario J, France (Received 22 July 2005; published 13 March 2006) Co and Na NMR are used to probe the local have performed a 59Co and 23Na NMR study which allows us to differentiate the two Co sites and to give

Paris-Sud 11, Université de

378

Mesoporous mixed metal oxides derived from P123-templated Mg-Al layered double hydroxides  

SciTech Connect

We report the preparation of mesoporous mixed metal oxides (MMOs) through a soft template method. Different amounts of P123 were used as structure directing agent to synthesize P123-templated Mg-Al layered double hydroxides (LDHs). After calcination of as-synthesized LDHs at 500 {sup o}C, the ordered mesopores were obtained by removal of P123. The mesoporous Mg-Al MMOs fabricated by using 2 wt% P123 exhibited a high specific surface area of 108.1 m{sup 2}/g, and wide distribution of pore size (2-18 nm). An investigation of the 'memory effect' of the mesoporous MMOs revealed that they were successfully reconstructed to ibuprofen intercalated LDHs having different gallery heights, which indicated different intercalation capacities. Due to their mesoporosity these unique MMOs have particular potential as drug or catalyst carriers. - Graphical abstract: Ordered mesoporous Mg-Al MMOs can be obtained through the calcination of P123-templated Mg-Al-CO{sub 3} LDHs. The pore diameter is 2.2 nm. At the presence of ibuprofen, the Mg-Al MMOs can recover to Mg-Al-IBU LDHs, based on its 'remember effect'. Display Omitted

Wang Jun, E-mail: zhqw1888@sohu.co [College of Material Science and Chemical Engineering, Harbin Engineering University, Harbin 150001 (China); College of Chemical Engineering, Harbin Institute of Technology, Harbin 150001 (China); Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, 150001 (China); Zhou Jideng; Li Zhanshuang; He Yang; Lin Shuangshuang; Liu Qi [College of Material Science and Chemical Engineering, Harbin Engineering University, Harbin 150001 (China); Zhang Milin [College of Material Science and Chemical Engineering, Harbin Engineering University, Harbin 150001 (China); Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, 150001 (China); Jiang Zhaohua [College of Chemical Engineering, Harbin Institute of Technology, Harbin 150001 (China)

2010-11-15T23:59:59.000Z

379

Final LDRD report : metal oxide films, nanostructures, and heterostructures for solar hydrogen production.  

Science Conference Proceedings (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

380

Investigation of zinc oxide doped with metal impurities for use as thin film conductive phosphors  

E-Print Network (OSTI)

Various technologies for manufacturing flat panel displays are currently being pursued world-wide. These include active matrix LCD, passive matrix LCD, and LED technologies, as well as several field emission approaches. To facilitate the development of a viable flat panel display, low voltage, conductive phosphors which emit blue, red, and green light will be required for the field emission technology. This thesis examines zinc oxide (ZnO) based thin ( ) phosphors for such an application. ZnO is a 11-VI wide bandgap semiconductor which exhibits green luminescence and has been shown to produce red luminescence as well. However, no blue light emission from ZnO thin film phosphors has been reported. An experimental survey has been conducted in which metal dopants were introduced in ZnO. This survey has revealed tungsten doped ZnO to be a previously unreported brilliant blue phosphor with high resistivity. Additional experiments indicated aluminum could be introduced in conjunction with the tungsten to increase the conductivity of the new blue ZnO phosphors. ZnO doped samples with varying amounts of tungsten and aluminum were subsequently prepared and tested. Optimization of the annealing conditions was then studied. The survey results are contained herein. Finally, it should be noted these phosphors have produced light when used as the anode material in vacuum field emission diodes.

Evatt, Steven R.

1994-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "transition metal oxides" from the National Library of EnergyBeta (NLEBeta).
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381

Titanium Oxide Aerogel Prepared from Titanium Metal and HydrogenPeroxide  

SciTech Connect

The reaction of hydrogen peroxide with excess titanium metal produces rigid titanium oxide aquagels. Subsequent solvent exchanges with ethanol and carbon dioxide, and supercritical drying produces the corresponding aerogels. The aerogels are translucent yellow in appearance, are amorphous to X-rays, and have a BET surface area of 350 m{sup 2}/g. The empirical formula of the material, as prepared, is TiO{sub 3}H{sub 2.7}C{sub 0.35}. Infrared spectroscopy indicates the presence of peroxide and carbonate groups. the microstructure of the aerogel consists of a network of elongated particles 2-5 nm in diameter and tens of nm in length. Thermal treatment under argon at 473 K causes rapid decomposition of the aerogel, forming a blue-gray powder consisting of a mixture of rutile and anatase with a surface area of 80 m{sup 2}/g. Additional thermal treatment at 973 K under air forms predominantly rutile, with a surface area of 20 m{sup 2}/g.

Ayers, M.R.; Hunt, A.J.

1997-03-01T23:59:59.000Z

382

Investigation of Some Transparent Metal Oxides as Damp Heat Protective Coating for CIGS Solar Cells: Preprint  

DOE Green Energy (OSTI)

We investigated the protective effectiveness of some transparent metal oxides (TMO) on CIGS solar cell coupons against damp heat (DH) exposure at 85oC and 85% relative humidity (RH). Sputter-deposited bilayer ZnO (BZO) with up to 0.5-um Al-doped ZnO (AZO) layer and 0.2-um bilayer InZnO were used as 'inherent' part of device structure on CdS/CIGS/Mo/SLG. Sputter-deposited 0.2-um ZnSnO and atomic layer deposited (ALD) 0.1-um Al2O3 were used as overcoat on typical BZO/CdS/CIGS/Mo/SLG solar cells. The results were all negative -- all TMO-coated CIGS cells exhibited substantial degradation in DH. Combining the optical photographs, PL and EL imaging, SEM surface micro-morphology, coupled with XRD, I-V and QE measurements, the causes of the device degradations are attributed to hydrolytic corrosion, flaking, micro-cracking, and delamination induced by the DH moisture. Mechanical stress and decrease in crystallinity (grain size effect) could be additional degrading factors for thicker AZO grown on CdS/CIGS.

Pern, F. J.; Yan, F.; Zaaunbrecher, B.; To, B.; Perkins, J.; Noufi, R.

2012-10-01T23:59:59.000Z

383

Resonant soft X-ray emission spectroscopy of vanadium oxides and related compounds  

E-Print Network (OSTI)

lithium-ion battery comprises a lithium containing transition metal oxide (TMO) cathode,ion battery using a Li- TMO cathode [95] (e.g. LiCoO 2 ), lithium

Schmitt, Thorsten

2004-01-01T23:59:59.000Z

384

Removal of metal oxide defects through improved semi-anisotropic wet etching process  

E-Print Network (OSTI)

Data recently collected from an industrial thin film manufacturer indicate that almost 8% of devices are rejected due to excess metal, or unwanted metal on the device surface. Experimentation and analysis suggest that ...

Dave, Neha H. (Neha Hemang)

2012-01-01T23:59:59.000Z

385

Measurement of the Nickel/Nickel Oxide Transition in Ni-Cr-Fe Alloys and Updated Data and Correlations to Quantify the Effect of Aqueous Hydrogen on Primary Water SCC  

DOE Green Energy (OSTI)

Alloys 600 and X-750 have been shown to exhibit a maximum in primary water stress corrosion cracking (PWSCC) susceptibility, when testing is conducted over a range of aqueous hydrogen (H{sub 2}) levels. Contact electric resistance (CER) and corrosion coupon testing using nickel specimens has shown that the maximum in SCC susceptibility occurs in proximity to the nickel-nickel oxide (Ni/NiO) phase transition. The measured location of the Ni/NiO transition has been shown to vary with temperature, from 25 scc/kg H{sub 2} at 360 C to 4 scc/kg H{sub 2} at 288 C. New CER measurements show that the Ni/NiO transition is located at 2 scc/kg H{sub 2} at 260 C. An updated correlation of the phase transition is provided. The present work also reports CER testing conducted using an Alloy 600 specimen at 316 C. A large change in resistance occurred between 5 and 10 scc/kg H{sub 2}, similar to the results obtained at 316 C using a nickel specimen. This result adds confidence in applying the Ni/NiO transition measurements to Ni-Cr-Fe alloys. The understanding of the importance of the Ni/NiO transition to PWSCC has been used previously to quantify H{sub 2} effects on SCC growth rate (SCCGR). Specifically, the difference in the electrochemical potential (EcP) of the specimen or component from the Ni/NiO transition (i.e., EcP{sub Ni/NiO}-EcP) has been used as a correlating parameter. In the present work, these SCCGR-H{sub 2} correlations, which were based on SCCGR data obtained at relatively high test temperatures (338 and 360 C), are evaluated via SCCGR tests at a reduced temperature (316 C). The 316 C data are in good agreement with the predictions, implying that the SCCGR-H{sub 2} correlations extrapolate well to reduced temperatures. The SCCGR-H{sub 2} correlations have been revised to reflect the updated Ni/NiO phase transition correlation. New data are presented for EN82H weld metal (also known as Alloy 82) at 338 C. Similar to other nickel alloys, SCC of EN82H is a function of the aqueous H{sub 2} level, with the SCCGR exhibiting a maximum near the Ni/NiO transition. For example, the SCCGR at 8 scc/kg H{sub 2} is {approx} 81 x higher than at 60 scc/kg H{sub 2}. The 8 scc/kg H{sub 2} condition is near the Ni/NiO transition (located at {approx} 14 scc/kg H{sub 2} at 338 C), while 60 scc/kg H{sub 2} is well into the nickel metal regime. A hydrogen-SCCGR correlation is provided for EN82H. The data and understanding obtained from the present work show that SCC can be mitigated by adjusting the aqueous H{sub 2} level. For example, SCCGR is typically minimized at relatively high aqueous H{sub 2} levels, that are well into the nickel metal regime (i.e., far from the Ni/NiO transition).

Steven A. Attanasio; David S. Morton

2003-06-16T23:59:59.000Z

386

Promises and problems with metallic interconnects for reduced temperature solid oxide fuel cells  

E-Print Network (OSTI)

Proceedings of Ist European SOFC Forum, U. Bossel , Editor,on Solid Oxide Fuel Cells (SOFC-VI) ed. S. C. Singhal etsolid oxide fuel cell (SOFC) development is towards lower

Hou, Peggy Y.; Huang, Keqin; Bakker, Wate T.

1999-01-01T23:59:59.000Z

387

High Activity of Ce1-xNixO2-y for H2 Production through Ethanol Steam Reforming: Tuning Catalytic Performance through Metal-Oxide Interactions  

SciTech Connect

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

388

On the Dissociation of Molecular Hydrogen by Au Supported on Transition Metal Carbides: Choice of the Most Active Support  

DOE Green Energy (OSTI)

A systematic density functional study of the adsorption and dissociation of H{sub 2} on the clean (001) surface of various transition metal carbides (TMCs; TM = Ti, Zr, V, Mo) and on Au{sub 4} nanoclusters supported on these TMCs is presented. It is found that the H{sub 2} dissociation on the bare clean TMCs strongly depends on the chemical nature of the support. Thus, the H{sub 2} molecule interacts rather strongly with TiC(001) and ZrC(001) but very weakly with VC(001) and {delta}-MoC(001). For the supported Au{sub 4} cluster, two different types of molecular mechanisms are found. For Au{sub 4}/TiC(001) and Au{sub 4}/ZrC(001), H{sub 2} dissociation leads to a H atom directly interacting with the Au{sub 4} cluster while the second H atom is transferred to the support. In contrast, for Au{sub 4}/VC(001) and Au{sub 4}/{delta}-MoC(001), both H atoms interact with the Au{sub 4} cluster. Overall, the present study suggests that, among the systems studied, Au/ZrC is the best substrate for H{sub 2} dissociation.

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

2011-03-15T23:59:59.000Z

389

HAT-P-18b and HAT-P-19b: Two Low-Density Saturn-Mass Planets Transiting Metal-Rich K Stars  

E-Print Network (OSTI)

We report the discovery of two new transiting extrasolar planets. HAT-P-18b orbits the V=12.759 K2 dwarf star GSC 2594-00646, with a period P=5.508023+-0.000006 d, transit epoch Tc=2454715.02174+-0.00020 (BJD), and transit duration 0.1131+-0.0009 d. The host star has a mass of 0.77+-0.03 Msun, radius of 0.75+-0.04 Rsun, effective temperature 4803+-80 K, and metallicity [Fe/H]=+0.10+-0.08. The planetary companion has a mass of 0.197+-0.013 Mjup, and radius of 0.995+-0.052 Rjup yielding a mean density of 0.25+-0.04 g cm-3. HAT-P-19b orbits the V=12.901 K1 dwarf star GSC 2283-00589, with a period P=4.008778+-0.000006 d, transit epoch Tc=2455091.53417+-0.00034 (BJD), and transit duration 0.1182+-0.0014 d. The host star has a mass of 0.84+-0.04 Msun, radius of 0.82+-0.05 Rsun, effective temperature 4990+-130 K, and metallicity [Fe/H]=+0.23+-0.08. The planetary companion has a mass of 0.292+-0.018 Mjup, and radius of 1.132+-0.072 Rjup yielding a mean density of 0.25+-0.04 g cm-3. The radial velocity residuals for H...

Hartman, J D; Sato, B; Torres, G; Noyes, R W; Latham, D W; Kovács, G; Fischer, D A; Howard, A W; Johnson, J A; Marcy, G W; Buchhave, L A; Füresz, G; Perumpilly, G; Béky, B; Stefanik, R P; Sasselov, D D; Esquerdo, G A; Everett, M; Csubry, Z; Lázár, J; Papp, I; Sári, P

2010-01-01T23:59:59.000Z

390

Support shape effect in metal oxide catalysis: ceria nanoshapes supported vanadia catalysts for oxidative dehydrogenation of iso-butane  

SciTech Connect

The activation energy of VOx/CeO2 catalysts in oxidative dehydrogenation of iso-butane was found dependent on the shape of ceria support: rods < octahedra, closely related to the surface oxygen vacancy formation energy and defects amount of the two ceria supports with different crystallographic surface planes.

Wu, Zili [ORNL; Schwartz, Viviane [ORNL; Li, Meijun [ORNL; Rondinone, Adam Justin [ORNL; Overbury, Steven {Steve} H [ORNL

2012-01-01T23:59:59.000Z

391

C-V characteristics of epitaxial germanium metal-oxide-semiconductor capacitor on GaAs substrate with ALD Al2O3 dielectric  

Science Conference Proceedings (OSTI)

Epitaxial germanium metal-oxide-semiconductor capacitors (MOSCAP) were fabricated on GaAs substrate using atomic layer deposited Al"2O"3 gate dielectric with surface treatments including pure HF and HF plus rapid thermal oxidation (RTO). The electrical ... Keywords: ALD Al2O3, CMOS integration, Ge MOSCAP, Ge epitaxial film, RTO

Shih Hsuan Tang; Chien I. Kuo; Hai Dang Trinh; Mantu Hudait; Edward Yi Chang; Ching Yi Hsu; Yung Hsuan Su; Guang-Li Luo; Hong Quan Nguyen

2012-09-01T23:59:59.000Z

392

Equation of State and Material Property Measurements of Hydrogen Isotopes at the High-Pressure, High-Temperature, Insulator-Metal Transition  

Science Conference Proceedings (OSTI)

A high-intensity laser was used to shock compress liquid deuterium to pressures between 0.22 and 3.4 megabars (Mbar). Shock density, pressure, and temperature were determined using a variety of experimental techniques and diagnostics. This pressure regime spans the transformation of deuterium from an insulating molecular fluid to an atomic metallic fluid. Data reveal a significant increase in compressibility and a temperature inflection near 1 Mbar, both indicative of such a transition. Single-wavelength reflectivity measurements of the shock front demonstrated that deuterium shocked above {approx}0.5 Mbar is indeed metallic. (c) 2000 The American Astronomical Society.

Cauble, R.; Celliers, P. M.; Collins, G. W.; Silva, L. B. da; Gold, D. M.; Foord, M. E.; Budil, K. S.; Wallace, R. J.; Ng, A.

2000-04-01T23:59:59.000Z

393

De Haas-Van Alphen measurements of one-electron and many-body effects in transition metals and intermetallic compounds  

SciTech Connect

Examples are given which demonstrate the power and versatility of the dHvA effect in studying electronic behavior in metals. In transition metals the parametrization schemes give a very complete and consistent picture of the k-dependent and surface averaged electronic properties. Because the one-electron behavior is fairly well known, the many body contribution to the Fermi velocity can be isolated and its detailed anisotropy can be displayed. This kind of information is directly relevant to the calculation of electron-phonon interaction effects and cannot be derived by any other means.

Crabtree, G.W.; Johanson, W.R.; Campbell, S.A.; Dye, D.H.; Karim, D.P.; Ketterson, J.B.

1980-01-01T23:59:59.000Z

394

Structurally-driven metal-insulator transition in Ca{sub 2}Ru{sub 1-x}Cr{sub x}O{sub 4} (0{<=}x<0.14): A single crystal X-ray diffraction study  

Science Conference Proceedings (OSTI)

Correlation between structure and transport properties are investigated in high-quality single-crystals of Ca{sub 2}Ru{sub 1-x}Cr{sub x}O{sub 4} with 013.5% and the system behaves as an insulator. Such a large, sharp metal-insulator transition and tuneable transition temperature may have potential applications in electronic devices. -- Graphical abstract: The metal-insulator transition temperature (T{sub MI}) was drastically reduced by Cr doping, and is closely related to the distortion of structure. Display Omitted Research highlights: {yields} The metal-insulator transition temperature (T{sub MI}) was drastically reduced by doping Cr into Ca{sub 2}RuO{sub 4} single crystal. {yields} Detailed single crystal structural analysis provided important insight into this structurally-driven metal-insulator transition. {yields} Negative Volume Thermal Expansion (NVTE) was observed with increasing temperature.

Qi, T.F., E-mail: tqi2@uky.ed [Center for Advanced Materials, University of Kentucky, Lexington, KY 40506 (United States); Department of Physics and Astronomy, University of Kentucky, Lexington, KY 40506 (United States); Ge, M. [Center for Advanced Materials, University of Kentucky, Lexington, KY 40506 (United States); High Magnetic Field Laboratory, University of Science and Technology of China, Hefei, Anhui 230026 (China); Korneta, O.B. [Center for Advanced Materials, University of Kentucky, Lexington, KY 40506 (United States); Department of Physics and Astronomy, University of Kentucky, Lexington, KY 40506 (United States); Parkin, S. [Center for Advanced Materials, University of Kentucky, Lexington, KY 40506 (United States); Department of Chemistry, University of Kentucky, Lexington, KY 40506 (United States); De Long, L.E.; Cao, G. [Center for Advanced Materials, University of Kentucky, Lexington, KY 40506 (United States); Department of Physics and Astronomy, University of Kentucky, Lexington, KY 40506 (United States)

2011-04-15T23:59:59.000Z

395

Solar Thermo-Chemical Splitting of Carbon Dioxide by Metal Oxide ...  

Science Conference Proceedings (OSTI)

Presentation Title, Solar Thermo-Chemical Splitting of Carbon Dioxide by Metal ... which can split carbon dioxide as well as water molecules by abstracting ...

396

The oxidation of binary alloys of chromium with metals of the first ...  

Science Conference Proceedings (OSTI)

oxide as the essential scale constituent is responsible for the change in ... Coles for laboratory facilities, and to the Science. Research Council for financial ...

397

In Vitro Evolution of a Peptide with a Hematite Binding Motif That May Constitute a Natural Metal-Oxide Binding Archetype  

DOE Green Energy (OSTI)

Phage-display technology was used to evolve peptides that selectively bind to the metal-oxide hematite (Fe2O3) from a library of approximately 3 billion different polypeptides. The sequences of these peptides contained the highly conserved amino acid motif, Ser/Thr-hydrophobic/aromatic-Ser/Thr-Pro-Ser/Thr. To better understand the nature of the peptide?metal oxide binding demonstrated by these experiments, molecular dynamics simulations were carried out for Ser-Pro-Ser at a hematite surface. These simulations show that hydrogen bonding occurs between the two serine amino acids and the hydroxylated hematite surface and that the presence of proline between the hydroxide residues restricts the peptide flexibility, thereby inducing a structural-binding motif. A search of published sequence data revealed that the binding motif (Ser/Thr-Pro-Ser/Thr) is adjacent to the terminal heme-binding domain of both OmcA and MtrC, which are outer membrane cytochromes from the metal-reducing bacterium Shewanella oneidensis MR-1. The entire five amino acid consensus sequence (Ser/Thr-hydrophobic/aromatic-Ser/Thr-Pro-Ser/Thr) was also found as multiple copies in the primary sequences of metal-oxide binding proteins Sil1 and Sil2 from Thalassiosira pseudonana. We suggest that this motif constitutes a natural metal-oxide binding archetype that could be exploited in enzyme-based biofuel cell design and approaches to synthesize tailored metal-oxide nanostructures.

Lower, Brian H.; Lins, Roberto D.; Oestreicher, Zachery W.; Straatsma, TP; Hochella Jr., Michael F.; Shi, Liang; Lower, Steven

2008-05-15T23:59:59.000Z

398

Rapid thermal cycling of metal-supported solid oxide fuel cell membranes  

E-Print Network (OSTI)

complete Fe30Cr+6AT-supported SOFC membrane after firing atof Fe-Cr ferritic steels as SOFC interconnect material," inmass production route for metallic SOFC-interconnectors," in

Matus, Yuriy B.; De Jonghe, Lutgard C.; Jacobson, Craig P.; Visco, Steven J.

2004-01-01T23:59:59.000Z

399

Study of Metal-oxide Composites Prepared by Ball Milling and ...  

Science Conference Proceedings (OSTI)

Aerosol Route Synthesis of Copper Oxide Nanoparticles Using Copper Nitrate Solution · AlGaAs-Based Optical ... Defect Energetics and Fission Product Transport in ZrC ... Enhancing Mineral Beneficiation by High Intensity Power Ultrasound.

400

Comparison between chemical vapor deposited and physical vapor deposited WSi{sub 2} metal gate for InGaAs n-metal-oxide-semiconductor field-effect transistors  

Science Conference Proceedings (OSTI)

We compare chemical vapor deposition (CVD) and physical vapor deposition (PVD) WSi{sub 2} metal gate process for In{sub 0.53}Ga{sub 0.47}As n-metal-oxide-semiconductor field-effect transistors using 10 and 6.5 nm Al{sub 2}O{sub 3} as dielectric layer. The CVD-processed metal gate device with 6.5 nm Al{sub 2}O{sub 3} shows enhanced transistor performance such as drive current, maximum transconductance and maximum effective mobility. These values are relatively better than the PVD-processed counterpart device with improvement of 51.8%, 46.4%, and 47.8%, respectively. The improvement for the performance of the CVD-processed metal gate device is due to the fluorine passivation at the oxide/semiconductor interface and a nondestructive deposition process.

Ong, B. S.; Pey, K. L. [Advanced Materials for Micro and Nano-Systems, Singapore-MIT Alliance, Singapore 637460 (Singapore); School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798 (Singapore); Ong, C. Y.; Tan, C. S. [School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798 (Singapore); Antoniadis, D. A. [Advanced Materials for Micro and Nano-Systems, Singapore-MIT Alliance, Singapore 637460 (Singapore); Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Fitzgerald, E. A. [Advanced Materials for Micro and Nano-Systems, Singapore-MIT Alliance, Singapore 637460 (Singapore); Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

2011-05-02T23:59:59.000Z

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

Electrical Contacts between Cathodes and Metallic Interconnects in Solid Oxide Fuel Cells  

Science Conference Proceedings (OSTI)

To minimize electrical resistance, contact layers are often included between interconnects and electrodes during construction of a SOFC stack. In this work, simulated cathode/interconnect structures were used to investigate the effects of different contact materials on the contact resistance between a LSF cathode and a Crofer22 APU interconnect.. The results from the resistance measurements are reported and correlated to interfacial interactions occurring between the metallic interconnect and the contact materials, particularly perovskites. The materials requirements for the contact layers between cathodes and metallic interconnects in intermediate temperature SOFCs are also discussed.

Yang, Z Gary; Xia, Gordon; Singh, Prabhakar; Stevenson, Jeffry W.

2006-04-21T23:59:59.000Z

402

Oxides having high energy densities  

DOE Patents (OSTI)

Certain disclosed embodiments generally relate to oxide materials having relatively high energy and/or power densities. Various aspects of the embodiments are directed to oxide materials having a structure B.sub.i(M.sub.jY.sub.k)O.sub.2, for example, a structure Li.sub.j(Ni.sub.jY.sub.k)O.sub.2 such as Li(Ni.sub.0.5Mn.sub.0.5)O.sub.2. In this structure, Y represents one or more atoms, each independently selected from the group consisting of alkaline earth metals, transition metals, Group 14 elements, Group 15, or Group 16 elements. In some embodiments, such an oxide material may have an O3 crystal structure, and/or a layered structure such that the oxide comprises a plurality of first, repeating atomic planes comprising Li, and a plurality of second, repeating atomic planes comprising Ni and/or Y.

Ceder, Gerbrand; Kang, Kisuk

2013-09-10T23:59:59.000Z

403

J8: Micro Fabrication of Metallic and Oxide Glasses for Terahertz ...  

Science Conference Proceedings (OSTI)

C19: Dissolution Behavior of Cu Under Bump Metallization in Ball Grid Array Structure ... E11: Evolution of the Grain Boundary Character Distribution During Grain ... for High Volume and Fast Turnaround Automated Inline TEM Sample Preparation .... H2: Triboluminescent Smart Sensors for Structural Health Monitoring.

404

Accelerated Publication: Ge metal-oxide-semiconductor devices with Al2O3/Ga2O3(Gd2O3) as gate dielectric  

Science Conference Proceedings (OSTI)

Ga"2O"3(Gd"2O"3) [GGO] 3.5nm-thick, with an in situ Al"2O"3 cap 1.5nm thick, has been directly deposited on Ge substrate without employing interfacial passivation layers. The equivalent oxide thickness (EOT) of the gate stack is 1.38-nm. The metal-oxide-semiconductor ... Keywords: EOT, Germanium, High-? dielectric, MOS

L. K. Chu; T. H. Chiang; T. D. Lin; Y. J. Lee; R. L. Chu; J. Kwo; M. Hong

2012-03-01T23:59:59.000Z

405

Method of producing highly oxidized superconductors containing barium, copper, and a third metal  

DOE Patents (OSTI)

Novel superconducting materials in the form of compounds, structures or phases are formed by performing otherwise known syntheses in a highly oxidizing atmosphere rather than that created by molecular oxygen at atmospheric pressure or below. This leads to the successful synthesis of novel superconducting compounds which are thermodynamically stable at the conditions under which they are formed.

Morris, Donald E. (Kensington, CA)

1996-01-01T23:59:59.000Z

406

Method of producing highly oxidized superconductors containing barium, copper, and a third metal  

DOE Patents (OSTI)

Novel superconducting materials in the form of compounds, structures or phases are formed by performing otherwise known syntheses in a highly oxidizing atmosphere rather than that created by molecular oxygen at atmospheric pressure or below. This leads to the successful synthesis of novel superconducting compounds which are thermodynamically stable at the conditions under which they are formed. 16 figs.

Morris, D.E.

1996-02-20T23:59:59.000Z

407

Bulk Metallic Glasses XI  

Science Conference Proceedings (OSTI)

Jul 15, 2013 ... A Bulk Metallic Glass with Record-breaking Damage Tolerance ... Oxidation on the Surface Characteristics of Zr-based Bulk Metallic Glasses.

408

Study of intermediates from transition metal excited-state electron-transfer reactions. [Annual] progress report, August 1, 1989--July 31, 1992  

SciTech Connect

Conventional and fast-kinetics techniques of photochemistry, photophysics, radiation chemistry, and electrochemistry were used to study the intermediates involved in transition metal excited-state electron-transfer reactions. These intermediates were excited state of Ru(II) and Cr(III) photosensitizers, their reduced forms, and species formed in reactions of redox quenchers and electron-transfer agents. Of particular concern was the back electron-transfer reaction between the geminate pair formed in the redox quenching of the photosensitizers, and the dependence of its rate on solution medium and temperature in competition with transformation and cage escape processes. (DLC)

Hoffman, M.Z.

1992-07-31T23:59:59.000Z

409

Spectroscopic investigations of small molecule interactions on metal oxide surfaces. Progress report, September 1, 1979-October 31, 1980  

DOE Green Energy (OSTI)

Significant advances were made over the past year in surveying with angle integrated uv photoelectron spectroscopy (UPS) the interactions of general classes of chemically important small molecules with metal oxide surfaces, and in elucidating in detail the geometric and electronic structures of the small molecule-surface complexes observed by angle resolved UPS. Progress can be divided into several areas: (1) a detailed understanding of the unique active site structures associated with the interaction of CO with ZnO utilizing angle integrated and angle resolved photoemission spectroscopy; (2) initiating survey studies into new small molecule systems with emphasis on hydrogen and ethylene; (3) successful construction and testing of a high resoltuion electron energy loss spectrometer (HREELS).

Solomon, E.I.; McFeeley, F.R.

1980-10-31T23:59:59.000Z

410

Use of impure inert gases in the controlled heating and cooling of mixed conducting metal oxide materials  

SciTech Connect

Method for processing an article comprising mixed conducting metal oxide material. The method comprises contacting the article with an oxygen-containing gas and either reducing the temperature of the oxygen-containing gas during a cooling period or increasing the temperature of the oxygen-containing gas during a heating period; during the cooling period, reducing the oxygen activity in the oxygen-containing gas during at least a portion of the cooling period and increasing the rate at which the temperature of the oxygen-containing gas is reduced during at least a portion of the cooling period; and during the heating period, increasing the oxygen activity in the oxygen-containing gas during at least a portion of the heating period and decreasing the rate at which the temperature of the oxygen-containing gas is increased during at least a portion of the heating period.

Carolan, Michael Francis (Allentown, PA); Bernhart, John Charles (Fleetwood, PA)

2012-08-21T23:59:59.000Z

411

Functionalized Graphene Sheets as Molecular Templates for Controlled Nucleation and Self-Assembly of Metal Oxide-Graphene Nanocomposites  

Science Conference Proceedings (OSTI)

Graphene sheets have been extensively studied as a key functional component of graphene-based nanocomposites for electronics, energy, catalysis,and sensing applications. However, fundamental understanding of the interfacial binding and nucleation processes at graphene surfaces remains lacking, and the range of controlled structures that can be produced are limited. Here, by using a combination of theoretical and experimental approaches, we demonstrate that functionalized graphene sheets (FGS) can function as a new class of molecular templates to direct nucleation and self-assembly and produce novel, three-dimensional nanocomposite materials. Two key aspects are demonstrated: First, the functional groups on FGS surface determine the nucleation energy, and thus control the nucleation sites and nucleation density, as well as the preferred crystalline phases. Second, FGS can function as a template to direct the self-assembly of surfactant micelles and produce ordered, mesoporous arrays of crystalline metal oxides and composites.

Li, Xiaolin; Qi, Wen N.; Mei, Donghai; Sushko, Maria L.; Aksay, Ilhan A.; Liu, Jun

2012-09-25T23:59:59.000Z

412

Method for improving the oxidation-resistance of metal substrates coated with thermal barrier coatings  

DOE Patents (OSTI)

A method for providing a protective coating on a metal-based substrate is disclosed. The method involves the application of an aluminum-rich mixture to the substrate to form a discontinuous layer of aluminum-rich particles, followed by the application of a second coating over the discontinuous layer of aluminum-rich particles. Aluminum diffuses from the aluminum-rich layer into the substrate, and into any bond coat layer which is subsequently applied. Related articles are also described.

Thompson, Anthony Mark (Niskayuna, NY); Gray, Dennis Michael (Delanson, NY); Jackson, Melvin Robert (Niskayuna, NY)

2002-01-01T23:59:59.000Z

413

Design and construction of a radiation resistant quadrupole using metal oxide insulated CICC  

SciTech Connect

The construction of a engineering test model of a radiation resistant quadrupole is described. The cold-iron quadrupole uses coils fabricated from metal-oixide (synthetic spinel) insulated Cable-In-Conduit-Conductor (CICC). The superconductor is NbTi in a copper matrix. The quadrupole is designed to produce a pole-tip field of 2 T with an operating current of 7,000 A.

Albert F. Zeller

2012-12-28T23:59:59.000Z

414

Degradation of solid oxide fuel cell metallic interconnects in fuels containing sulfur  

DOE Green Energy (OSTI)

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

415

Transition metal complexes of oxazolinylboranes and cyclopentadienyl-bis(oxazolinyl)borates: Catalysts for asymmetric olefin hydroamination and acceptorless alcohol decarbonylation  

Science Conference Proceedings (OSTI)

The research presented and discussed in this dissertation involves the synthesis of transition metal complexes of oxazolinylboranes and cyclopentadienyl-bis(oxazolinyl)borates, and their application in catalytic enantioselective olefin hydroamination and acceptorless alcohol decarbonylation. Neutral oxazolinylboranes are excellent synthetic intermediates for preparing new borate ligands and also developing organometallic complexes. Achiral and optically active bis(oxazolinyl)phenylboranes are synthesized by reaction of 2-lithio-2-oxazolide and 0.50 equiv of dichlorophenylborane. These bis(oxazolinyl)phenylboranes are oligomeric species in solid state resulting from the coordination of an oxazoline to the boron center of another borane monomer. The treatment of chiral bis(oxazolinyl)phenylboranes with sodium cyclopentadienide provide optically active cyclopentadienyl-bis(oxazolinyl)borates H[PhB(C{sub 5}H{sub 5})(Ox{sup R}){sub 2}] [Ox{sup R} = Ox{sup 4S-iPr,Me2}, Ox{sup 4R-iPr,Me2}, Ox{sup 4S-tBu]}. These optically active proligands react with an equivalent of M(NMe{sub 2}){sub 4} (M = Ti, Zr, Hf) to afford corresponding cyclopentadienyl-bis(oxazolinyl)borato group 4 complexes {PhB(C{sub 5}H{sub 4})(Ox{sup R}){sub 2}}M(NMe{sub 2}){sub 2} in high yields. These group 4 compounds catalyze cyclization of aminoalkenes at room temperature or below, providing pyrrolidine, piperidine, and azepane with enantiomeric excesses up to 99%. Our mechanistic investigations suggest a non-insertive mechanism involving concerted C?N/C?H bond formation in the turnover limiting step of the catalytic cycle. Among cyclopentadienyl-bis(oxazolinyl)borato group 4 catalysts, the zirconium complex {PhB(C{sub 5}H{sub 4})(Ox{sup 4S-iPr,Me2}){sub 2}}Zr(NMe{sub 2}){sub 2} ({S-2}Zr(NMe{sub 2}){sub 2}) displays highest activity and enantioselectivity. Interestingly, {S-2}Zr(NMe{sub 2}){sub 2} also desymmetrizes olefin moieties of achiral non-conjugated aminodienes and aminodiynes during cyclization. The cyclization of aminodienes catalyzed by {S-2}Zr(NMe{sub 2}){sub 2} affords diastereomeric mixture of cis and trans cylic amines with high diasteromeric ratios and excellent enantiomeric excesses. Similarly, the desymmetrization of alkyne moieties in {S-2}Zr(NMe{sub 2}){sub 2}-catalyzed cyclization of aminodiynes provides corresponding cyclic imines bearing quaternary stereocenters with enantiomeric excesses up to 93%. These stereoselective desymmetrization reactions are significantly affected by concentration of the substrate, temperature, and the presence of a noncyclizable primary amine. In addition, both the diastereomeric ratios and enantiomeric excesses of the products are markedly enhanced by N-deuteration of the substrates. Notably, the cationic zirconium-monoamide complex [{S-2}Zr(NMe{sub 2})][B(C{sub 6}F{sub 5}){sub 4}] obtained from neutral {S-2}Zr(NMe{sub 2}){sub 2} cyclizes primary aminopentenes providing pyrrolidines with S-configuration; whereas {S-2}Zr(NMe{sub 2}){sub 2} provides R-configured pyrrolidines. The yttrium complex {S-2}YCH{sub 2}SiMe{sub 3} also affords S-configured pyrrolidines by cyclization of aminopentenes, however the enantiomeric excesses of products are low. An alternative optically active yttrium complex {PhB(C{sub 5}H{sub 4})(Ox{sup 4S-tBu}){sub 2}}YCH{sub 2}SiMe{sub 3} ({S-3}YCH{sub 2}SiMe{sub 3}) is synthesized, which displays highly enantioselective in the cyclization of aminoalkenes at room temperature affording S-configured cyclic amines with enantiomeric excesses up to 96%. A noninsertive mechanism involving a six-membered transition state by a concerted C?N bond formation and N?H bond cleavage is proposed for {S-3}YCH{sub 2}SiMe{sub 3} system based on the kinetic, spectroscopic, and stereochemical features. In the end, a series of bis- and tris(oxazolinyl)borato iridium and rhodium complexes are synthesized with bis(oxazolinyl)phenylborane [PhB(Ox{sup Me2}){sub 2}]{sub n}, tris(oxazolinyl)borane [B(Ox{sup Me2}){sub 3}]n, and tris(4,4-dimethyl-2-oxazolinyl)phenylborate [To{sup M}]{sup ?}. All these new an

Manna, Kuntal [Ames Laboratory

2012-12-17T23:59:59.000Z

416

Creation of Exotic Features in Metal Oxides by Surface Treatment for Enhanced Gas Sensing  

E-Print Network (OSTI)

followed by oxidation in a well-defined pO2 regime near the M-MOx proximity line by a suitable buffer gas Model. Fig. 4. Thermodynamic criteria for several M/MOx coexistence and practical pO2 regimes for phase as a function of temperature for several M-MOx pairs. By manipulating the ambient pO2 across these lines, one

Azad, Abdul-Majeed

417

Photo-oxidation catalysts  

DOE Patents (OSTI)

Photo-oxidation catalysts and methods for cleaning a metal-based catalyst are disclosed. An exemplary catalyst system implementing a photo-oxidation catalyst may comprise a metal-based catalyst, and a photo-oxidation catalyst for cleaning the metal-based catalyst in the presence of light. The exposure to light enables the photo-oxidation catalyst to substantially oxidize absorbed contaminants and reduce accumulation of the contaminants on the metal-based catalyst. Applications are also disclosed.

Pitts, J. Roland (Lakewood, CO); Liu, Ping (Irvine, CA); Smith, R. Davis (Golden, CO)

2009-07-14T23:59:59.000Z

418

Melanin as a target for melanoma chemotherapy: Pro-oxidant effect of oxygen and metals on melanoma viability  

E-Print Network (OSTI)

La Jolla, CA, USA). Indium tin oxide plates were purchasedand hydrophilic indium tin oxide (ITO). While the magnitude

Farmer, Patrick J; Gidanian, S; Shahandeh, B; Di Bilio, A J; Tohidian, N; Meyskens, F L

2003-01-01T23:59:59.000Z

419

Reducing the deactivation of Ni-metal during the catalytic partial oxidation of a surrogate diesel fuel mixture  

SciTech Connect

Ni catalysts are active and selective for the conversion of hydrocarbon into synthesis gas. However, conventional supported Ni catalysts rapidly deactivate at the high temperatures required for partial oxidation of diesel fuel by sintering and metal vaporization, as well as by carbon deposition and sulfur poisoning. Thus, to reduce deactivation Ni (3 wt%) was substituted into the structures of Ba-hexaaluminate (BNHA) and La–Sr–Zr pyrochlore (LSZN), and their activity was compared to a supported Ni/Al2O3 for the catalytic partial oxidation (CPOX) of a surrogate diesel fuel. Characterization by XRD showed a single phase #2;-alumina for the hexaaluminate, while LSZN had a pyrochlore structure with a defect SrZrO3 perovskite phase. Temperature programmed reduction experiments confirmed Ni was reducible in all catalysts. XANES results confirmed that Ni atoms were substituted into the hexaaluminate and pyrochlore structures, as spectra for each catalyst showed different coordination environments for Ni compared to a NiO standard. During CPOX activity tests (T = 900 ?C and WHSV= 50,000 scc/gcat/h), the LSZN pyrochlore produced stable H2 and CO yields in the presence of 5 wt% 1-methylnaphthalene and 50ppmw dibenzothiophene/n-tetradecane for 2 h, while both Ni/Al2O3 and BNHA catalysts were irreversibly deactivated by this mixture over the same time. Activity loss was strongly linked to carbon formation.

Haynes, D.; Campos, A.; Smith, M.; Berry, D.; Shekhawat, D.; Spivey, J.

2010-01-01T23:59:59.000Z

420

Molybdenum-based additives to mixed-metal oxides for use in hot gas cleanup sorbents for the catalytic decomposition of ammonia in coal gases  

DOE Patents (OSTI)

This invention relates to additives to mixed-metal oxides that act simultaneously as sorbents and catalysts in cleanup systems for hot coal gases. Such additives of this type, generally, act as a sorbent to remove sulfur from the coal gases while substantially simultaneously, catalytically decomposing appreciable amounts of ammonia from the coal gases.

Ayala, Raul E. (Clifton Park, NY)

1993-01-01T23:59:59.000Z

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

Strained Ge channel p-type metal-oxide-semiconductor field-effect transistors grown on Siâ?â??xGex/Si virtual substrates  

E-Print Network (OSTI)

We have fabricated strained Ge channel p-type metal-oxide-semiconductor field-effect transistors (p-MOSFETs) on Siâ??.â??Geâ??.â?? virtual substrates. The poor interface between silicon dioxide (SiOâ??) and the Ge channel ...

Lee, Minjoo L.

422

Determining the Behavior of RuO(x) Nanoparticles in Mixed-Metal Oxides:  

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

Mechanism of Ethanol Synthesis from Syngas on Rh(111) Understanding of Mechanism of Ethanol Synthesis from Syngas on Rh(111) Understanding of ethanol decomposition on Rh(1 1 1) from density functional theory and kinetic Monte Carlo simulations Theoretical perspective of alcohol decomposition and synthesis from CO2 hydrogenation