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Sample records for cu-based catalyst systems

  1. Orthogonal Pd- and Cu-Based Catalyst Systems for the C- and N-Arylation of Oxindoles

    PubMed Central

    Altman, Ryan A.; Hyde, Alan M.; Huang, Xiaohua; Buchwald, Stephen L.

    2008-01-01

    In the cross-coupling reactions of unprotected oxindoles with aryl halides, Pd- and Cu-based catalyst systems displayed orthogonal chemoselectivity. A Pd/dialkylbiarylphosphine-based catalyst system chemoselectively arylated oxindole at the 3-position, while arylation occurred exclusively at the nitrogen using a Cu/diamine-based catalyst system. Computational examination of the relevant L1Pd(Ar)(oxindolate) and diamine-Cu-(oxindolate) species were performed to gain mechanistic insight into the controlling features of the observed chemoselectivity. PMID:18588302

  2. Heterogeneous Catalytic Conversion of Dry Syngas to Ethanol and Higher Alcohols on Cu-Based Catalysts

    SciTech Connect

    Gupta, Mayank; Smith, Miranda L.; Spivey, James J.

    2011-04-19

    Ethanol and higher alcohols have been identified as potential fuel additives or hydrogen carriers for use in fuel cells. One method of ethanol production is catalytic conversion of syngas (a mixture of CO, H₂, CO₂, and H₂O), derived from biomass, coal, or natural gas. Thermodynamics of CO hydrogenation shows that ethanol is favored as the sole product at conditions of practical interest, but if methane is allowed as product in this analysis, essentially no ethanol is formed at equilibrium. The kinetics of ethanol formation must therefore be maximized. Although rhodium-based catalysts give C{sup 2+} oxygenates with high selectivity, their prohibitive cost has spurred research on less expensive copper-based alternatives. Copper-based catalysts require an optimum amount of promoter to suppress undesired reactions and maximize the yields of ethanol and higher alcohols. Common promoters include alkali, transition metals and their oxides, and rare earth oxides. Careful selection of operating variables is also necessary to achieve the desired activity and selectivity. This review describes the effects of promoters, supports, and operating conditions on the performance of copper-based catalysts for conversion of dry syngas to ethanol and higher alcohols. Proposed mechanisms from the literature for ethanol and higher-alcohol synthesis are outlined.

  3. System for reactivating catalysts

    SciTech Connect

    Ginosar, Daniel M.; Thompson, David N.; Anderson, Raymond P.

    2010-03-02

    A method of reactivating a catalyst, such as a solid catalyst or a liquid catalyst is provided. The method comprises providing a catalyst that is at least partially deactivated by fouling agents. The catalyst is contacted with a fluid reactivating agent that is at or above a critical point of the fluid reactivating agent and is of sufficient density to dissolve impurities. The fluid reactivating agent reacts with at least one fouling agent, releasing the at least one fouling agent from the catalyst. The at least one fouling agent becomes dissolved in the fluid reactivating agent and is subsequently separated or removed from the fluid reactivating agent so that the fluid reactivating agent may be reused. A system for reactivating a catalyst is also disclosed.

  4. Plasmatron-catalyst system

    SciTech Connect

    Bromberg, Leslie; Cohn, Daniel R.; Rabinovich, Alexander; Alexeev, Nikolai

    2007-10-09

    A plasmatron-catalyst system. The system generates hydrogen-rich gas and comprises a plasmatron and at least one catalyst for receiving an output from the plasmatron to produce hydrogen-rich gas. In a preferred embodiment, the plasmatron receives as an input air, fuel and water/steam for use in the reforming process. The system increases the hydrogen yield and decreases the amount of carbon monoxide.

  5. Catalyst system comprising a first catalyst system tethered to a supported catalyst

    DOEpatents

    Angelici, R.J.; Gao, H.

    1998-08-04

    The present invention provides new catalyst formats which comprise a supported catalyst tethered to a second and different catalyst by a suitable tethering ligand. A preferred system comprises a heterogeneous supported metal catalyst tethered to a homogeneous catalyst. This combination of homogeneous and heterogeneous catalysts has a sufficient lifetime and unusually high catalytic activity in arene hydrogenations, and potentially many other reactions as well, including, but not limited to hydroformylation, hydrosilication, olefin oxidation, isomerization, hydrocyanidation, olefin metathesis, olefin polymerization, carbonylation, enantioselective catalysis and photoduplication. These catalysts are easily separated from the products, and can be reused repeatedly, making these systems very economical. 2 figs.

  6. Catalyst system comprising a first catalyst system tethered to a supported catalyst

    DOEpatents

    Angelici, Robert J.; Gao, Hanrong

    1998-08-04

    The present invention provides new catalyst formats which comprise a supported catalyst tethered to a second and different catalyst by a suitable tethering ligand. A preferred system comprises a heterogeneous supported metal catalyst tethered to a homogeneous catalyst. This combination of homogeneous and heterogeneous catalysts has a sufficient lifetime and unusually high catalytic activity in arene hydrogenations, and potentially many other reactions as well, including, but not limited to hydroformylation, hydrosilation, olefin oxidation, isomerization, hydrocyanation, olefin metathesis, olefin polymerization, carbonylation, enantioselective catalysis and photoduplication. These catalysts are easily separated from the products, and can be reused repeatedly, making these systems very economical.

  7. Catalyst systems and uses thereof

    DOEpatents

    Ozkan, Umit S [Worthington, OH; Holmgreen, Erik M [Columbus, OH; Yung, Matthew M [Columbus, OH

    2012-07-24

    A method of carbon monoxide (CO) removal comprises providing an oxidation catalyst comprising cobalt supported on an inorganic oxide. The method further comprises feeding a gaseous stream comprising CO, and oxygen (O.sub.2) to the catalyst system, and removing CO from the gaseous stream by oxidizing the CO to carbon dioxide (CO.sub.2) in the presence of the oxidation catalyst at a temperature between about 20 to about 200.degree. C.

  8. HERFD-XANES and XES as complementary operando tools for monitoring the structure of Cu-based zeolite catalysts during NOx-removal by ammonia SCR

    NASA Astrophysics Data System (ADS)

    Günter, T.; Doronkin, D. E.; Carvalho, H. W. P.; Casapu, M.; Grunwaldt, J.-D.

    2016-05-01

    In this article, we demonstrate the potential of hard X-ray techniques to characterize catalysts under working conditions. Operando high energy resolution fluorescence detected (HERFD) XANES and valence to core (vtc) X-ray emission spectroscopy (XES) have been used in a spatially-resolved manner to study Cu-zeolite catalysts during the standard-SCR reaction and related model conditions. The results show a gradient in Cu oxidation state and coordination along the catalyst bed as the reactants are consumed. Vtc-XES gives complementary information on the direct adsorption of ammonia at the Cu sites. The structural information on the catalyst shows the suitability of X-ray techniques to understand catalytic reactions and to facilitate catalyst optimization.

  9. Catalyst for microelectromechanical systems microreactors

    DOEpatents

    Morse, Jeffrey D [Martinez, CA; Sopchak, David A [Livermore, CA; Upadhye, Ravindra S [Pleasanton, CA; Reynolds, John G [San Ramon, CA; Satcher, Joseph H [Patterson, CA; Gash, Alex E [Brentwood, CA

    2011-11-15

    A microreactor comprising a silicon wafer, a multiplicity of microchannels in the silicon wafer, and a catalyst coating the microchannels. In one embodiment the catalyst coating the microchannels comprises a nanostructured material. In another embodiment the catalyst coating the microchannels comprises an aerogel. In another embodiment the catalyst coating the microchannels comprises a solgel. In another embodiment the catalyst coating the microchannels comprises carbon nanotubes.

  10. Catalyst for microelectromechanical systems microreactors

    DOEpatents

    Morse, Jeffrey D.; Sopchak, David A.; Upadhye, Ravindra S.; Reynolds, John G.; Satcher, Joseph H.; Gash, Alex E.

    2010-06-29

    A microreactor comprising a silicon wafer, a multiplicity of microchannels in the silicon wafer, and a catalyst coating the microchannels. In one embodiment the catalyst coating the microchannels comprises a nanostructured material. In another embodiment the catalyst coating the microchannels comprises an aerogel. In another embodiment the catalyst coating the microchannels comprises a solgel. In another embodiment the catalyst coating the microchannels comprises carbon nanotubes.

  11. Synergy in Lignin Upgrading by a Combination of Cu-Based Mixed Oxide and Ni-Phosphide Catalysts in Supercritical Ethanol

    PubMed Central

    2017-01-01

    The depolymerization of lignin to bioaromatics usually requires a hydrodeoxygenation (HDO) step to lower the oxygen content. A mixed Cu–Mg–Al oxide (CuMgAlOx) is an effective catalyst for the depolymerization of lignin in supercritical ethanol. We explored the use of Ni-based cocatalysts, i.e. Ni/SiO2, Ni2P/SiO2, and Ni/ASA (ASA = amorphous silica alumina), with the aim of combining lignin depolymerization and HDO in a single reaction step. While the silica-supported catalysts were themselves hardly active in lignin upgrading, Ni/ASA displayed comparable lignin monomer yield as CuMgAlOx. A drawback of using an acidic support is extensive dehydration of the ethanol solvent. Instead, combining CuMgAlOx with Ni/SiO2 and especially Ni2P/SiO2 proved to be effective in increasing the lignin monomer yield, while at the same time reducing the oxygen content of the products. With Ni2P/SiO2, the lignin monomer yield was 53 wt %, leading to nearly complete deoxygenation of the aromatic products.

  12. Process of activation of a palladium catalyst system

    SciTech Connect

    Sobolevskiy, Anatoly; Rossin, Joseph A.; Knapke, Michael J.

    2011-08-02

    Improved processes for activating a catalyst system used for the reduction of nitrogen oxides are provided. In one embodiment, the catalyst system is activated by passing an activation gas stream having an amount of each of oxygen, water vapor, nitrogen oxides, and hydrogen over the catalyst system and increasing a temperature of the catalyst system to a temperature of at least 180.degree. C. at a heating rate of from 1-20.degree./min. Use of activation processes described herein leads to a catalyst system with superior NOx reduction capabilities.

  13. Supported catalyst systems and method of making biodiesel products using such catalysts

    DOEpatents

    Kim, Manhoe; Yan, Shuli; Salley, Steven O.; Ng, K. Y. Simon

    2015-10-20

    A heterogeneous catalyst system, a method of preparing the catalyst system and a method of forming a biodiesel product via transesterification reactions using the catalyst system is disclosed. The catalyst system according to one aspect of the present disclosure represents a class of supported mixed metal oxides that include at least calcium oxide and another metal oxide deposited on a lanthanum oxide or cerium oxide support. Preferably, the catalysts include CaO--CeO.sub.2ZLa.sub.2O.sub.3 or CaO--La.sub.2O.sub.3/CeO.sub.2. Optionally, the catalyst may further include additional metal oxides, such as CaO--La.sub.2O.sub.3--GdOxZLa.sub.2O.sub.3.

  14. Correlation between viscous-flow activation energy and phase diagram in four systems of Cu-based alloys

    NASA Astrophysics Data System (ADS)

    Ning, Shuang; Bian, Xiufang; Ren, Zhenfeng

    2010-09-01

    Activation energy is obtained from temperature dependence of viscosities by means of a fitting to the Arrhenius equation for liquid alloys of Cu-Sb, Cu-Te, Cu-Sn and Cu-Ag systems. We found that the changing trend of activation energy curves with concentration is similar to that of liquidus in the phase diagrams. Moreover, a maximum value of activation energy is in the composition range of the intermetallic phases and a minimum value of activation energy is located at the eutectic point. The correlation between the activation energy and the phase diagrams has been further discussed.

  15. Multi-stage catalyst systems and uses thereof

    DOEpatents

    Ozkan, Umit S.; Holmgreen, Erik M.; Yung, Matthew M.

    2009-02-10

    Catalyst systems and methods provide benefits in reducing the content of nitrogen oxides in a gaseous stream containing nitric oxide (NO), hydrocarbons, carbon monoxide (CO), and oxygen (O.sub.2). The catalyst system comprises an oxidation catalyst comprising a first metal supported on a first inorganic oxide for catalyzing the oxidation of NO to nitrogen dioxide (NO.sub.2), and a reduction catalyst comprising a second metal supported on a second inorganic oxide for catalyzing the reduction of NO.sub.2 to nitrogen (N.sub.2).

  16. Stability of a Bifunctional Cu-Based Core@Zeolite Shell Catalyst for Dimethyl Ether Synthesis Under Redox Conditions Studied by Environmental Transmission Electron Microscopy and In Situ X-Ray Ptychography.

    PubMed

    Baier, Sina; Damsgaard, Christian D; Klumpp, Michael; Reinhardt, Juliane; Sheppard, Thomas; Balogh, Zoltan; Kasama, Takeshi; Benzi, Federico; Wagner, Jakob B; Schwieger, Wilhelm; Schroer, Christian G; Grunwaldt, Jan-Dierk

    2017-04-05

    When using bifunctional core@shell catalysts, the stability of both the shell and core-shell interface is crucial for catalytic applications. In the present study, we elucidate the stability of a CuO/ZnO/Al2O3@ZSM-5 core@shell material, used for one-stage synthesis of dimethyl ether from synthesis gas. The catalyst stability was studied in a hierarchical manner by complementary environmental transmission electron microscopy (ETEM), scanning electron microscopy (SEM) and in situ hard X-ray ptychography with a specially designed in situ cell. Both reductive activation and reoxidation were applied. The core-shell interface was found to be stable during reducing and oxidizing treatment at 250°C as observed by ETEM and in situ X-ray ptychography, although strong changes occurred in the core on a 10 nm scale due to the reduction of copper oxide to metallic copper particles. At 350°C, in situ X-ray ptychography indicated the occurrence of structural changes also on the µm scale, i.e. the core material and parts of the shell undergo restructuring. Nevertheless, the crucial core-shell interface required for full bifunctionality appeared to remain stable. This study demonstrates the potential of these correlative in situ microscopy techniques for hierarchically designed catalysts.

  17. CATALYSTS NHI Thermochemical Systems FY 2009 Year-End Report

    SciTech Connect

    Daniel M. Ginosar

    2009-09-01

    Fiscal Year 2009 work in the Catalysts project focused on advanced catalysts for the decomposition of sulfuric acid, a reaction common to both the Sulfur-Iodine (S-I) cycle and the Hybrid Sulfur cycle. Prior years’ effort in this project has found that although platinum supported on titanium oxide will be an acceptable catalyst for sulfuric acid decomposition in the integrated laboratory scale (ILS) project, the material has short comings, including significant cost and high deactivation rates due to sintering and platinum evaporation. For pilot and larger scale systems, the catalyst stability needs to be improved significantly. In Fiscal Year 2008 it was found that at atmospheric pressure, deactivation rates of a 1 wt% platinum catalyst could be reduced by 300% by adding either 0.3 wt% iridium (Ir) or 0.3 wt% ruthenium (Ru) to the catalyst. In Fiscal Year 2009, work focused on examining the platinum group metal catalysts activity and stability at elevated pressures. In addition, simple and complex metal oxides are known to catalyze the sulfuric acid decomposition reaction. These metal oxides could offer activities comparable to platinum but at significantly reduced cost. Thus a second focus for Fiscal Year 2009 was to explore metal oxide catalysts for the sulfuric acid decomposition reaction. In Fiscal Year 2007 several commercial activated carbons had been identified for the HI decomposition reaction; a reaction specific to the S-I cycle. Those materials should be acceptable for the pilot scale project. The activated carbon catalysts have some disadvantages including low activity at the lower range of reactor operating temperature (350 to 400°C) and a propensity to generate carbon monoxide in the presence of water that could contaminate the hydrogen product, but due to limited funding, this area had low priority in Fiscal Year 2009. Fiscal Year 2009 catalyst work included five tasks: development, and testing of stabilized platinum based H2SO4 catalysts

  18. Catalyst system for the polymerization of alkenes to polyolefins

    DOEpatents

    Miller, Stephen A.; Bercaw, John E.

    2002-01-01

    The invention provides metallocene catalyst systems for the controlled polymerization of alkenes to a wide variety of polyolefins and olefin coplymers. Catalyst systems are provided that specifically produce isotactic, syndiotactic and steroblock polyolefins. The type of polymer produced can be controlled by varying the catalyst system, specifically by varying the ligand substituents. Such catalyst systems are particularly useful for the polymerization of polypropylene to give elastomeric polypropylenes. The invention also provides novel elastomeric polypropylene polymers characterized by dyad (m) tacticities of about 55% to about 65%, pentad (mmmm) tacticities of about 25% to about 35%, molecular weights (M.sub.w)in the range of about 50,000 to about 2,000,000, and have mmrm+rrmr peak is less than about 5%.

  19. Catalyst system for the polymerization of alkenes to polyolefins

    DOEpatents

    Miller, Stephen A.; Bercaw, John E.

    2004-02-17

    The invention provides metallocene catalyst systems for the controlled polymerization of alkenes to a wide variety of polyolefins and olefin coplymers. Catalyst systems are provided that specifically produce isotactic, syndiotactic and steroblock polyolefins. The type of polymer produced can be controlled by varying the catalyst system, specifically by varying the ligand substituents. Such catalyst systems are particularly useful for the polymerization of polypropylene to give elastomeric polypropylenes. The invention also provides novel elastomeric polypropylene polymers characterized by dyad (m) tacticities of about 55% to about 65%, pentad (mmmm) tacticities of about 25% to about 35%, molecular weights (M.sub.W) in the range of about 50,000 to about 2,000,000, and have mmrm+rrmr peak is less than about 5%.

  20. Low temperature catalyst system for methanol production

    DOEpatents

    Sapienza, R.S.; Slegeir, W.A.; O'Hare, T.E.

    1984-04-20

    This patent discloses a catalyst and process useful at low temperatures (150/sup 0/C) and preferably in the range 80 to 120/sup 0/C used in the production of methanol from carbon monoxide and hydrogen. The catalyst components are used in slurry form and comprise (1) a complex reducing agent derived from the component structure NaH-ROH-M(OAc)/sub 2/ where M is selected from the group consisting of Ni, Pd, and Co and R is a lower alkyl group containing 1 to 6 carbon atoms and (2) a metal carbonyl of a group VI (Mo, Cr, W) metal. For the first component, Nic is preferred (where M = Ni and R = tertiary amyl). For the second component, Mo(CO)/sub 6/ is preferred. The mixture is subjected to a conditioning or activating step under temperature and pressure, similar to the parameters given above, to afford the active catalyst.

  1. Oxidation catalyst

    DOEpatents

    Ceyer, Sylvia T.; Lahr, David L.

    2010-11-09

    The present invention generally relates to catalyst systems and methods for oxidation of carbon monoxide. The invention involves catalyst compositions which may be advantageously altered by, for example, modification of the catalyst surface to enhance catalyst performance. Catalyst systems of the present invention may be capable of performing the oxidation of carbon monoxide at relatively lower temperatures (e.g., 200 K and below) and at relatively higher reaction rates than known catalysts. Additionally, catalyst systems disclosed herein may be substantially lower in cost than current commercial catalysts. Such catalyst systems may be useful in, for example, catalytic converters, fuel cells, sensors, and the like.

  2. Cathodic catalysts in bioelectrochemical systems for energy recovery from wastewater.

    PubMed

    Liu, Xian-Wei; Li, Wen-Wei; Yu, Han-Qing

    2014-11-21

    Bioelectrochemical systems (BESs), in which microorganisms are utilized as a self-regenerable catalyst at the anode of an electrochemical cell to directly extract electrical energy from organic matter, have been widely recognized as a promising technology for energy-efficient wastewater treatment or even for net energy generation. However, currently BES performance is constrained by poor cathode reaction kinetics. Thus, there is a strong impetus to improve the cathodic catalysis performance through proper selection and design of catalysts. This review introduces the fundamentals and current development status of various cathodic catalysts (including electrocatalysts, photoelectrocatalysts and bioelectrocatalysts) in BES, identifies their limitations and influential factors, compares their catalytic performances in terms of catalytic efficiency, stability, selectivity, etc., and discusses the possible optimization strategies and future research directions. Special focus is given on the analysis of how the catalytic performance of different catalysts can be improved by fine tuning their physicochemical or physiological properties.

  3. Catalysts for portable, solid state hydrogen genration systems

    NASA Astrophysics Data System (ADS)

    Gabl, Jason Robert

    Hydrogen and air powered proton exchange membrane fuel cells are a potential alternative to batteries. In portable power systems, the design requirements often focus on cost efficiency, energy density, storability, as well as safety. Ammonia borane (AB), a chemical hydride containing 19.6 wt. % hydrogen, has a high hydrogen capacity and is a stable and non-toxic candidate for storing hydrogen in portable systems. Throughout this work, Department of Energy guidelines for low power portable hydrogen power systems were used as a baseline and comparison with commercially available systems. In order to make this comparison, the system parameters of a system using AB hydrolysis were estimated by developing capacity and cost correlations from the commercial systems and applying them to this work. Supporting experiments were designed to evaluate a system that would use a premixed solid storage bed of AB and a catalyst. This configuration would only require a user input of water in order to initiate the hydrogen production. Using ammonia borane hydrolysis, the hydrogen yield is ˜9 wt. %, when all reactants are considered. In addition to the simplicity of initiating the reaction, hydrolysis of AB has the advantage of suppressing the production of some toxic borazines that are present when AB is thermally decomposed. However, ammonia gas will be formed and this problem must be addressed, as ammonia is damaging to PEM fuel cells. The catalyst focused on throughout this work was Amberlyst - 15; an ion exchange resin with an acid capacity of 4.7 eq/kg and ammonia adsorbent. At less than 0.30/g, this is a cost effective alternative to precious metal catalysts. The testing with this catalyst was compared to a traditional catalyst in literature, 20% platinum in carbon, costing more than 40/g. The Amberlyst catalyst was found to reduce the formation of ammonia in the gas products from ˜3.71 wt. % with the Pt/C catalyst to <0.01 wt. %. Since Amberlyst adsorbs ammonia, it acts as a

  4. A Primer for the NEWBASIC/CATALYST System.

    ERIC Educational Resources Information Center

    Dwyer, Thomas A.; And Others

    Assuming no previous experience with computers, this primer is designed to help students, teachers, scientists, and other scholars to learn how to use the NEWBASIC/CATALYST system (NBS). The primer contains nine sections: (1) instructions for establishing contact with the computer (logging on); (2) examples and problems to lead the student through…

  5. Sol-gel based oxidation catalyst and coating system using same

    NASA Technical Reports Server (NTRS)

    Watkins, Anthony N. (Inventor); Leighty, Bradley D. (Inventor); Oglesby, Donald M. (Inventor); Ingram, JoAnne L. (Inventor); Schryer, Jacqueline L. (Inventor)

    2010-01-01

    An oxidation catalyst system is formed by particles of an oxidation catalyst dispersed in a porous sol-gel binder. The oxidation catalyst system can be applied by brush or spray painting while the sol-gel binder is in its sol state.

  6. Reducing fischer-tropsch catalyst attrition losses in high agitation reaction systems

    DOEpatents

    Singleton, Alan H.; Oukaci, Rachid; Goodwin, James G.

    2001-01-01

    A method for reducing catalyst attrition losses in hydrocarbon synthesis processes conducted in high agitation reaction systems; a method of producing an attrition-resistant catalyst; a catalyst produced by such method; a method of producing an attrition-resistant catalyst support; and a catalyst support produced by such method. The inventive method of reducing catalyst attrition losses comprises the step of reacting a synthesis gas in a high agitation reaction system in the presence of a catalyst. In one aspect, the catalyst preferably comprises a .gamma.-alumina support including an amount of titanium effective for increasing the attrition resistance of the catalyst. In another aspect, the catalyst preferably comprises a .gamma.-alumina support which has been treated, after calcination, with an acidic, aqueous solution. The acidic aqueous solution preferably has a pH of not more than about 5. In another aspect, the catalyst preferably comprises cobalt on a .gamma.-alumina support wherein the cobalt has been applied to the .gamma.-alumina support by totally aqueous, incipient wetness-type impregnation. In another aspect, the catalyst preferably comprises cobalt on a .gamma.-alumina support with an amount of a lanthana promoter effective for increasing the attrition resistance of the catalyst. In another aspect, the catalyst preferably comprises a .gamma.-alumina support produced from boehmite having a crystallite size, in the 021 plane, in the range of from about 30 to about 55 .ANG.ngstrons. In another aspect, the inventive method of producing an attrition-resistant catalyst comprises the step of treating a .gamma.-alumina support, after calcination of and before adding catalytic material to the support, with an acidic solution effective for increasing the attrition resistance of the catalyst. In another aspect, the inventive method of producing an attrition-resistant catalyst support comprises the step of treating calcined .gamma.-alumina with an acidic, aqueous

  7. Self-Supported Cu-Based Nanowire Arrays as Noble-Metal-Free Electrocatalysts for Oxygen Evolution.

    PubMed

    Hou, Chun-Chao; Fu, Wen-Fu; Chen, Yong

    2016-08-23

    Crystalline Cu-based nanowire arrays (NWAs) including Cu(OH)2 , CuO, Cu2 O, and CuOx are facilely grown on Cu foil and are found to act as highly efficient, low-cost, and robust electrocatalysts for the oxygen evolution reaction (OER). Impressively, this noble-metal-free 3 D Cu(OH)2 -NWAs/Cu foil electrode shows the highest catalytic activity with a Tafel slope of 86 mV dec(-1) , an overpotential (η) of about 530 mV at ∼10 mA cm(-2) (controlled-potential electrolysis method without iR correction) and almost 100 % Faradic efficiency, paralleling the performance of the state-of-the-art RuO2 OER catalyst in 0.1 m NaOH solution (pH 12.8). To the best of our knowledge, this work represents one of the best results ever reported on Cu-based OER systems.

  8. CATALYST ACTIVITY MAINTENANCE FOR THE LIQUID PHASE SYNTHESIS GAS-TO-DIMETHYL ETHER PROCESS PART II: DEVELOPMENT OF ALUMINUM PHOSPHATE AS THE DEHYDRATION CATALYST FOR THE SINGLE-STEP LIQUID PHASE SYNGAS-TO-DME PROCESS

    SciTech Connect

    Xiang-Dong Peng

    2002-05-01

    At the heart of the single-step liquid phase syngas-to-DME process (LPDME{trademark}) is a catalyst system that can be active as well as stable. In the Alternative Fuels I program, a dual-catalyst system containing a Cu-based commercial methanol synthesis catalyst (BASF S3-86) and a commercial dehydration material ({gamma}-alumina) was demonstrated. It provided the productivity and selectivity expected from the LPDME process. However, the catalyst system deactivated too rapidly to warrant a viable commercial process [1]. The mechanistic investigation in the early part of the DOE's Alternative Fuels II program revealed that the accelerated catalyst deactivation under LPDME conditions is due to detrimental interaction between the methanol synthesis catalyst and methanol dehydration catalyst [2,3]. The interaction was attributed to migration of Cu- and/or Zn-containing species from the synthesis catalyst to the dehydration catalyst. Identification of a dehydration catalyst that did not lead to this detrimental interaction while retaining adequate dehydration activity was elusive. Twenty-nine different dehydration materials were tested, but none showed the desired performance [2]. The search came to a turning point when aluminum phosphate was tested. This amorphous material is prepared by precipitating a solution containing Al(NO{sub 3}){sub 3} and H{sub 3}PO{sub 4} with NH{sub 4}OH, followed by washing, drying and calcination. The aluminum phosphate catalyst has adequate dehydration activity and good stability. It can co-exist with the Cu-based methanol synthesis catalyst without negatively affecting the latter catalyst's stability. This report documents the details of the development of this catalyst. These include initial leads, efforts in improving activity and stability, investigation and development of the best preparation parameters and procedures, mechanistic understanding and resulting preparation guidelines, and the accomplishments of this work.

  9. Photo-oxidation catalysts

    DOEpatents

    Pitts, J. Roland; Liu, Ping; Smith, R. Davis

    2009-07-14

    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.

  10. ENVIRONMENTAL TECHNOLOGY VERIFICATION, TEST REPORT OF MOBILE SOURCE EMISSIONS CONTROL DEVICES/CLEAN DIESEL TECHNOLOGIES FUEL BORNE CATALYST WITH CLEANAIR SYSTEM'S DIESEL OXIDATION CATALYST

    EPA Science Inventory

    The Environmental Technology Verification report discusses the technology and performance of the Fuel-Borne Catalyst with CleanAir System's Diesel Oxidation Catalyst manufactured by Clean Diesel Technologies, Inc. The technology is a fuel-borne catalyst used in ultra low sulfur d...

  11. Novel catalysts and photoelectrochemical system for solar fuel production

    NASA Astrophysics Data System (ADS)

    Zhang, Yan

    Solar fuel production from abundant raw chemicals such as CO2 and water is highly desired as a clean renewable energy solution for the future. Developing photoelectrochemical cells is viewed as a promising approach to realize this energy conversion and storage process. Efficient and robust oxygen evolution catalyst made from non-precious materials remains a major challenge for such a system. This thesis basically consists of three parts of work, including studies on enhancing the photocatalytic oxygen evolution activity of cobalt-based spinel nanoparticles by manganese3+ substitution, in situ formation of cobalt oxide nanocubanes as highly active catalyst for photocatalytic oxygen evolution reaction, and development of a photoanode-driven photoelectrochemical cell for CO2 reduction with water. The first part of this thesis work devotes efforts in the development and study on cobalt and other transition metal oxide based oxygen evolution catalyst. Photocatalytic oxygen evolution is a critical step for solar fuel production from abundant sources. It poses a significant challenge because it requires an efficient catalyst to bridge the one-electron photon capture process with the four-electron oxygen reaction. Among all the metal oxides, Co3O4 spinel exhibits a high activity as an oxygen evolution catalyst. The results of this work demonstrate that the photocatalytic oxygen evolution activity of Co3O4 spinel can be further enhanced by substituting Co with Mn in the spinel structure. Using a facile hydrothermal approach, Co3O4 spinel nanoparticles as well as Mn-substituted and Ni-substituted Co3O4 spinel nanoparticles with a typical particle size of 5-7 nm were successfully synthesized. The morphology and crystal structures of the as-synthesized nanoparticle catalysts have been carefully examined using various structural characterization techniques, including powder x-ray diffraction (PXRD), transmission electron microscope (TEM), gas adsorption, and x-ray absorption

  12. Water-gas shift on gold catalysts: catalyst systems and fundamental studies.

    PubMed

    Tao, Franklin Feng; Ma, Zhen

    2013-10-07

    Since the pioneering finding by Haruta et al. that small gold nanoparticles on reducible supports can be highly active for low-temperature CO oxidation, the synthesis, characterization, and application of supported gold catalysts have attracted much attention. The water-gas shift reaction (WGSR: CO + H2O = CO2 + H2) is important for removing CO and upgrading the purity of H2 for fuel cell applications, ammonia synthesis, and selective hydrogenation processes. In recent years, much attention has been paid to exploration the possibility of using supported gold nanocatalysts for WGSR and understanding the fundamental aspects related to catalyst deactivation mechanisms, nature of active sites, and reaction mechanisms. Here we summarize recent advances in the development of supported gold catalysts for this reaction and fundamental insights that can be gained, and furnish our assessment on the status of research progress.

  13. Ruthenium on rutile catalyst, catalytic system, and method for aqueous phase hydrogenations

    DOEpatents

    Elliot, Douglas C.; Werpy, Todd A.; Wang, Yong; Frye, Jr., John G.

    2001-01-01

    An essentially nickel- and rhenium-free catalyst is described comprising ruthenium on a titania support where the titania is greater than 75% rutile. A catalytic system containing a nickel-free catalyst comprising ruthenium on a titania support where the titania is greater than 75% rutile, and a method using this catalyst in the hydrogenation of an organic compound in the aqueous phase is also described.

  14. Low-temperature NOx reduction processes using combined systems of pulsed corona discharge and catalysts

    NASA Astrophysics Data System (ADS)

    Kim, H. H.; Takashima, K.; Katsura, S.; Mizuno, A.

    2001-02-01

    In this paper, we will report NOx removal via reduction processes using two types of combined system of pulse corona discharge and catalysts: the single-stage plasma-driven catalyst (PDC) system, and the two-stage plasma-enhanced selective catalytic reduction (PE-SCR) system. Several catalysts, such as γ-alumina catalysts, mechanically mixed catalysts of γ-alumina with BaTiO3 or TiO2, and Co-ZSM-5 were tested. In the PDC system, which is directly activated by the discharge plasma, it was found that the use of additives was necessary to achieve NOx removal by reduction. Removal rates of NO and NOx were linearly increased as the molar ratio of additive to NOx increased. The dependence of NO and NOx removal on the gas hourly space velocity (GHSV) at a fixed specific input energy (SIE) indicates that plasma-induced surface reaction on the catalyst plays an important role in the PDC system. It was found that the optimal GHSV of the PDC system with the γ-alumina catalyst was smaller than 6000 h-1. Mechanical mixing of γ-alumina with BaTiO3 or TiO2 did not enhance NO and NOx removal and γ-alumina alone was found to be the most suitable catalyst. The dielectric constant of the catalyst only influenced the plasma intensity, not the NOx removal. In the PE-SCR system, plasma-treated NOx (mostly NO2) was reduced effectively with NH3 over the Co-ZSM-5 catalyst at a relatively low temperature of 150 °C. Under optimal conditions the energy cost and energy yield were 25 eV/molecule and 21 g-N (kWh)-1, respectively.

  15. Non-precious bimetallic catalysts for selective dehydrogenation of an organic chemical hydride system.

    PubMed

    Al-ShaikhAli, Anaam H; Jedidi, Abdesslem; Cavallo, Luigi; Takanabe, Kazuhiro

    2015-08-21

    Methylcyclohexane (MCH)-toluene (TOL) chemical hydride cycles as hydrogen carrier systems are successful with the selective dehydrogenation of MCH to TOL, which has been achieved only using precious Pt-based catalysts. Herein, we report improved selectivity using non-precious metal nickel-based bimetallic catalysts, where the second metal occupies the unselective step sites.

  16. Development of micro-cogeneration system with porous catalyst microcombustor

    NASA Astrophysics Data System (ADS)

    Takahashi, S.; Tanaka, M.; Ieda, N.; Ihara, T.

    2015-10-01

    A self-standing micro-cogeneration system was developed by coupling a microcombustor, thermoelectric (TE) modules, and an air supply device. The microcombustor has a porous monolithic Pt catalyst layer, and a combustion efficiency of 90% was achieved. A microblower is used to supply air to the combustor, and it is driven by electricity from the Bi-Te TE modules through a dc-dc converter. We investigated the optimal point where the output became maximal and the system was self-standing. At the optimal point, the input fuel enthalpy was 13.2 W, and 440 mW of electricity was generated from the TE modules. The microblower consumed 280 mW, and the net generated electricity was 160 mW. Therefore, the final thermal efficiency was 1.21%. The net thermal efficiency of the developed system was the same magnitude as that of TeeDee01 (COX Co. Ltd.), the world’s smallest model plane engine (0.163 cc), even though the magnitude of the output power was less than 1/20 in comparison.

  17. Catalysts, systems and methods to reduce NOX in an exhaust gas stream

    DOEpatents

    Castellano, Christopher R.; Moini, Ahmad; Koermer, Gerald S.; Furbeck, Howard

    2010-07-20

    Catalysts, systems and methods are described to reduce NO.sub.x emissions of an internal combustion engine. In one embodiment, an emissions treatment system for an exhaust stream is provided having an SCR catalyst comprising silver tungstate on an alumina support. The emissions treatment system may be used for the treatment of exhaust streams from diesel engines and lean burn gasoline engines. An emissions treatment system may further comprise an injection device operative to dispense a hydrocarbon reducing agent upstream of the catalyst.

  18. PILOT TESTING OF MERCURY OXIDATION CATALYSTS FOR UPSTREAM OF WET FGD SYSTEMS

    SciTech Connect

    Gary M. Blythe

    2003-07-01

    This document summarizes progress on Cooperative Agreement DE-FC26-01NT41185, ''Pilot Testing of Mercury Oxidation Catalysts for Upstream of Wet FGD Systems,'' during the time-period April 1, 2003 through June 30, 2003. The objective of this project is to demonstrate at pilot scale the use of solid honeycomb catalysts to promote the oxidation of elemental mercury in the flue gas from coal combustion. The project is being funded by the U.S. DOE National Energy Technology Laboratory under Cooperative Agreement DE-FC26-01NT41185. EPRI, Great River Energy (GRE), and City Public Service (CPS) of San Antonio are project cofunders. URS Group is the prime contractor. The mercury control process under development uses catalyst materials applied to honeycomb substrates to promote the oxidation of elemental mercury in the flue gas from coal-fired power plants that have wet lime or limestone flue gas desulfurization (FGD) systems. Oxidized mercury is removed in the wet FGD absorbers and co-precipitates with the byproducts from the FGD system. The current project is testing previously identified, effective catalyst materials at a larger, pilot scale and in a commercial form, to provide engineering data for future full-scale designs. The pilot-scale tests will continue for approximately 14 months at each of two sites to provide longer-term catalyst life data. This is the seventh full reporting period for the subject Cooperative Agreement. During this period, project efforts included continued operation of the first pilot unit, conducting catalyst activity measurements, installing sonic horns for on-line catalyst cleaning, and installing the fourth catalyst, all for the GRE Coal Creek site. CPS began installation of the second mercury oxidation catalyst pilot unit at their Spruce Plant during the quarter. Laboratory efforts were conducted to support catalyst selection for that second pilot unit. This technical progress report provides an update on these efforts.

  19. PILOT TESTING OF MERCURY OXIDATION CATALYSTS FOR UPSTREAM OF WET FGD SYSTEMS

    SciTech Connect

    Gary M. Blythe

    2003-10-01

    This document summarizes progress on Cooperative Agreement DE-FC26-01NT41185, ''Pilot Testing of Mercury Oxidation Catalysts for Upstream of Wet FGD Systems,'' during the time-period July 1, 2003 through September 30, 2003. The objective of this project is to demonstrate at pilot scale the use of solid honeycomb catalysts to promote the oxidation of elemental mercury in the flue gas from coal combustion. The project is being funded by the U.S. DOE National Energy Technology Laboratory under Cooperative Agreement DE-FC26-01NT41185. EPRI, Great River Energy (GRE), and City Public Service (CPS) of San Antonio are project cofunders. URS Group is the prime contractor. The mercury control process under development uses catalyst materials applied to honeycomb substrates to promote the oxidation of elemental mercury in the flue gas from coal-fired power plants that have wet lime or limestone flue gas desulfurization (FGD) systems. Oxidized mercury is removed in the wet FGD absorbers and co-precipitates with the byproducts from the FGD system. The current project is testing previously identified, effective catalyst materials at a larger, pilot scale and in a commercial form, to provide engineering data for future full-scale designs. The pilot-scale tests will continue for approximately 14 months at each of two sites to provide longer-term catalyst life data. This is the eighth full reporting period for the subject Cooperative Agreement. During this period, project efforts included continued operation of the first pilot unit at the GRE Coal Creek site with all four catalysts in service and sonic horns installed for on-line catalyst cleaning. During the quarter, a catalyst activity measurement trip and mercury SCEM relative accuracy tests were completed, and catalyst pressure drop was closely monitored with the sonic horns in operation. CPS completed the installation of the second mercury oxidation catalyst pilot unit at their Spruce Plant during the quarter, and the four

  20. Reforming catalysts

    SciTech Connect

    Givens, E.N.; Plank, C.J.; Rosinski, E.J.

    1980-03-04

    Crystalline aluminosilicate zeolites are mixed with conventional reforming catalysts to produce new catalytic compositions with high catalytic activity and selectivity and excellent aging characteristics. These new catalytic compositions may be utilized alone or in conjunction with conventional reforming catalysts. The acidic activity of the total catalyst system is controlled within defined limits. When so controlled the utility of these catalyst systems in reforming hydrocarbon mixtures is to reduce the C1 and C2 concentrations in reformer gas product, while increasing the C3 and C4 concentrations and maintaining high liquid yield at high octane numbers.

  1. PILOT TESTING OF MERCURY OXIDATION CATALYSTS FOR UPSTREAM OF WET FGD SYSTEMS

    SciTech Connect

    Gary M. Blythe

    2003-05-01

    This document summarizes progress on Cooperative Agreement DE-FC26-01NT41185, ''Pilot Testing of Mercury Oxidation Catalysts for Upstream of Wet FGD Systems,'' during the time period January 1, 2003 through March 31, 2003. The objective of this project is to demonstrate at pilot scale the use of solid honeycomb catalysts to promote the oxidation of elemental mercury in the flue gas from coal combustion. The project is being funded by the U.S. DOE National Energy Technology Laboratory under Cooperative Agreement DE-FC26-01NT41185. EPRI, Great River Energy (GRE), and City Public Service (CPS) of San Antonio are project cofunders. URS Group is the prime contractor. The mercury control process under development uses catalyst materials applied to honeycomb substrates to promote the oxidation of elemental mercury in the flue gas from coal-fired power plants that have wet lime or limestone flue gas desulfurization (FGD) systems. Oxidized mercury is removed in the wet FGD absorbers and co-precipitates with the byproducts from the FGD system. The current project is testing previously identified, effective catalyst materials at a larger, pilot scale and in a commercial form, to provide engineering data for future full-scale designs. The pilot-scale tests will continue for up to 14 months at each of two sites to provide longer-term catalyst life data. This is the sixth full reporting period for the subject Cooperative Agreement. During this period, project efforts included continued operation of the pilot unit with three catalysts, conducting catalyst activity measurements, and procuring the fourth catalyst, all for the GRE Coal Creek pilot unit site. Laboratory efforts were also conducted to support catalyst selection for the second pilot unit site, at CPS' Spruce Plant. This technical progress report provides an update on these efforts.

  2. Pilot Testing of Mercury Oxidation Catalysts for Upstream of Wet FGD Systems

    SciTech Connect

    Richard Rhudy

    2006-06-30

    This final report presents and discusses results from a mercury control process development project entitled ''Pilot Testing of Mercury Oxidation Catalysts for Upstream of Wet FGD Systems''. The objective of this project was to demonstrate at pilot scale a mercury control technology that uses solid honeycomb catalysts to promote the oxidation of elemental mercury in the flue gas from coal combustion. Oxidized mercury is removed in downstream wet flue gas desulfurization (FGD) absorbers and leaves with the FGD byproducts. The goal of the project was to achieve 90% oxidation of elemental mercury in the flue gas and 90% overall mercury capture with the downstream wet FGD system. The project was co-funded by EPRI and the U.S. Department of Energy's National Energy Technology Laboratory (DOE NETL) under Cooperative Agreement DE-FC26-01NT41185. Great River Energy (GRE) and City Public Service (now CPS Energy) of San Antonio were also project co-funders and provided host sites. URS Group, Inc. was the prime contractor. Longer-term pilot-scale tests were conducted at two sites to provide catalyst life data. GRE provided the first site, at their Coal Creek Station (CCS), which fires North Dakota lignite, and CPS Energy provided the second site, at their Spruce Plant, which fires Powder River Basin (PRB) coal. Mercury oxidation catalyst testing began at CCS in October 2002 and continued through the end of June 2004, representing nearly 21 months of catalyst operation. An important finding was that, even though the mercury oxidation catalyst pilot unit was installed downstream of a high-efficiency ESP, fly ash buildup began to plug flue gas flow through the horizontal catalyst cells. Sonic horns were installed in each catalyst compartment and appeared to limit fly ash buildup. A palladium-based catalyst showed initial elemental mercury oxidation percentages of 95% across the catalyst, declining to 67% after 21 months in service. A carbon-based catalyst began with almost 98

  3. Removal of ammonia from urine vapor by a dual-catalyst system

    NASA Technical Reports Server (NTRS)

    Budininkas, P.

    1977-01-01

    The feasibility of removing ammonia from urine vapor by a low-temperature dual-catalyst system has been demonstrated. The process is based on the catalytic oxidation of ammonia to a mixture of nitrogen, nitrous oxide, and water, followed by a catalytic decomposition of the nitrous oxide into its elements. Potential ammonia oxidation and nitrous oxide decomposition catalysts were first screened with artificial gas mixtures, then tested with the actual urine vapor produced by boiling untreated urine. A suitable dual-catalyst bed arrangement was found that achieved the removal of ammonia and also organic carbon, and recovered water of good quality from urine vapor.

  4. System and method for determining an ammonia generation rate in a three-way catalyst

    SciTech Connect

    Sun, Min; Perry, Kevin L; Kim, Chang H

    2014-12-30

    A system according to the principles of the present disclosure includes a rate determination module, a storage level determination module, and an air/fuel ratio control module. The rate determination module determines an ammonia generation rate in a three-way catalyst based on a reaction efficiency and a reactant level. The storage level determination module determines an ammonia storage level in a selective catalytic reduction (SCR) catalyst positioned downstream from the three-way catalyst based on the ammonia generation rate. The air/fuel ratio control module controls an air/fuel ratio of an engine based on the ammonia storage level.

  5. Exhaust system having a gold-platinum group metal catalyst

    DOEpatents

    Ragle, Christie Susan [Havana, IL; Silver, Ronald G [Peoria, IL; Zemskova, Svetlana Mikhailovna [Edelstein, IL; Eckstein, Colleen J [Metamora, IL

    2011-12-06

    A method of providing an exhaust treatment device is disclosed. The method includes applying a catalyst including gold and a platinum group metal to a particulate filter. The concentration of the gold and the platinum group metal is sufficient to enable oxidation of carbon monoxide and nitric oxide.

  6. Exhaust system having a gold-platinum group metal catalyst

    DOEpatents

    Ragle, Christie Susan; Silver, Ronald G.; Zemskova, Svetlana Mikhailovna; Eckstein, Colleen J.

    2012-08-07

    A method of providing an exhaust treatment device is disclosed. The method includes applying a catalyst including gold and a platinum group metal to a particulate filter. The concentration of the gold and the platinum group metal is sufficient to enable oxidation of carbon monoxide and nitric oxide.

  7. PILOT TESTING OF MERCURY OXIDATION CATALYSTS FOR UPSTREAM OF WET FGD SYSTEMS

    SciTech Connect

    Gary M. Blythe

    2003-01-21

    This document summarizes progress on Cooperative Agreement DE-FC26-01NT41185, Pilot Testing of Mercury Oxidation Catalysts for Upstream of Wet FGD Systems, during the time period October 1, 2002 through December 31, 2002. The objective of this project is to demonstrate at pilot scale the use of solid honeycomb catalysts to promote the oxidation of elemental mercury in the flue gas from coal combustion. The project is being funded by the U.S. DOE National Energy Technology Laboratory under Cooperative Agreement DE-FC26-01NT41185. EPRI, Great River Energy (GRE), and City Public Service (CPS) of San Antonio are project co-funders. URS Group is the prime contractor. The mercury catalytic oxidation process under development uses catalyst materials applied to honeycomb substrates to promote the oxidation of elemental mercury in the flue gas from coal-fired power plants that have wet lime or limestone flue gas desulfurization (FGD) systems. Oxidized mercury is removed in the wet FGD absorbers and co-precipitates with the byproducts from the FGD system. The co-precipitated mercury does not appear to adversely affect the disposal or reuse properties of the FGD byproduct. The current project testing previously identified, effective catalyst materials at a larger, pilot scale and in a commercial form, to provide engineering data for future fullscale designs. The pilot-scale tests will continue for up to 14 months at each of two sites to provide longer-term catalyst life data. This is the fifth full reporting period for the subject Cooperative Agreement. During this period, project efforts included starting up the pilot unit with three catalysts at the first site, conducting catalyst activity measurements, completing comprehensive flue gas sampling and analyses, and procuring additional catalysts for the pilot unit. This technical progress report provides an update on these efforts.

  8. Evaluation of Bosch-Based Systems Using Non-Traditional Catalysts at Reduced Temperatures

    NASA Technical Reports Server (NTRS)

    Abney, Morgan B.; Mansell, J. Matthew

    2011-01-01

    Oxygen and water resupply make open loop atmosphere revitalization (AR) systems unfavorable for long-term missions beyond low Earth orbit. Crucial to closing the AR loop are carbon dioxide reduction systems with low mass and volume, minimal power requirements, and minimal consumables. For this purpose, NASA is exploring using Bosch-based systems. The Bosch process is favorable over state-of-the-art Sabatier-based processes due to complete loop closure. However, traditional operation of the Bosch required high reaction temperatures, high recycle rates, and significant consumables in the form of catalyst resupply due to carbon fouling. A number of configurations have been proposed for next-generation Bosch systems. First, alternative catalysts (catalysts other than steel wool) can be used in a traditional single-stage Bosch reactor to improve reaction kinetics and increase carbon packing density. Second, the Bosch reactor may be split into separate stages wherein the first reactor stage is dedicated to carbon monoxide and water formation via the reverse water-gas shift reaction and the second reactor stage is dedicated to carbon formation. A series system will enable maximum efficiency of both steps of the Bosch reaction, resulting in optimized operation and maximum carbon formation rate. This paper details the results of testing of both single-stage and two-stage Bosch systems with alternative catalysts at reduced temperatures. These results are compared to a traditional Bosch system operated with a steel wool catalyst.

  9. Full-Scale Testing of a Mercury Oxidation Catalyst Upstream of a Wet FGD System

    SciTech Connect

    Gary Blythe; Jennifer Paradis

    2010-06-30

    This document presents and discusses results from Cooperative Agreement DE-FC26-06NT42778, 'Full-scale Testing of a Mercury Oxidation Catalyst Upstream of a Wet FGD System,' which was conducted over the time-period July 24, 2006 through June 30, 2010. The objective of the project was to demonstrate at full scale the use of solid honeycomb catalysts to promote the oxidation of elemental mercury in pulverized-coal-fired flue gas. Oxidized mercury is removed downstream in wet flue gas desulfurization (FGD) absorbers and collected with the byproducts from the FGD system. The project was co-funded by EPRI, the Lower Colorado River Authority (LCRA), who also provided the host site, Great River Energy, Johnson Matthey, Southern Company, Salt River Project (SRP), the Tennessee Valley Authority (TVA), NRG Energy, Ontario Power and Westar. URS Group was the prime contractor and also provided cofunding. The scope of this project included installing and testing a gold-based catalyst upstream of one full-scale wet FGD absorber module (about 200-MW scale) at LCRA's Fayette Power Project (FPP) Unit 3, which fires Powder River Basin coal. Installation of the catalyst involved modifying the ductwork upstream of one of three wet FGD absorbers on Unit 3, Absorber C. The FGD system uses limestone reagent, operates with forced sulfite oxidation, and normally runs with two FGD modules in service and one spare. The full-scale catalyst test was planned for 24 months to provide catalyst life data. Over the test period, data were collected on catalyst pressure drop, elemental mercury oxidation across the catalyst module, and mercury capture by the downstream wet FGD absorber. The demonstration period began on May 6, 2008 with plans for the catalyst to remain in service until May 5, 2010. However, because of continual increases in pressure drop across the catalyst and concerns that further increases would adversely affect Unit 3 operations, LCRA decided to end the demonstration early, during

  10. Recycling nanoparticle catalysts without separation based on a pickering emulsion/organic biphasic system.

    PubMed

    Liu, Huifang; Zhang, Zhiming; Yang, Hengquan; Cheng, Fangqin; Du, Zhiping

    2014-07-01

    A conceptually novel methodology is explored for in situ recycling of nanoparticle catalysts based on transforming a conventional organic/aqueous biphasic system into a Pickering emulsion/organic biphasic system (PEOBS). The suggested PEOBS exists as two phases, with the nanoparticle catalyst "anchored" in the Pickering emulsion phase, but is "continuous" between the organic phase and the continuous phase of the Pickering emulsion. Aqueous hydrogenations are used to evaluate the reaction performances of PEOBS, and the underlying principles of PEOBS are preliminarily elaborated. The unique properties of PEOBS lead to many intriguing findings, which are unlikely to be achieved in the reported biphasic systems. PEOBS exhibits more than a fourfold enhancement in catalysis efficiency in comparison with a conventional biphasic system. Impressively, PEOBS enables the organic product to be facilely isolated through simple decantation and the nanoparticle catalyst can be recycled in situ without the need for "separation". Its recycling effectiveness is justified by ten reaction cycles without significant catalyst loss. The simple protocol, in conjunction with the stability to simultaneously achieve high catalysis efficiency and excellent catalyst recyclability, makes PEOBS a promising methodology to develop more sustainable nanocatalysis.

  11. Environmentally-benign catalysts for the selective catalytic reduction of NO(x) from diesel engines: structure-activity relationship and reaction mechanism aspects.

    PubMed

    Liu, Fudong; Yu, Yunbo; He, Hong

    2014-08-11

    Selective catalytic reduction of NOx using NH3 or hydrocarbons (NH3-SCR or HC-SCR) in oxygen-rich exhaust from diesel engines remains a major challenge in environmental catalysis. The development of highly efficient, stable and environmentally-benign catalysts for SCR processes is very important for practical use. In this feature article, the structure-activity relationship of vanadium-free catalysts in the NH3-SCR reaction is discussed in detail, including Fe-, Ce-based oxide catalysts and Fe-, Cu-based zeolite catalysts, which is beneficial for catalyst redesign and activity improvement. Based on our research, a comprehensive mechanism contributing to the performance of Ag/Al2O3 in HC-SCR is provided, giving a clue to the design of a catalytic system with high efficiency.

  12. PILOT TESTING OF MERCURY OXIDATION CATALYSTS FOR UPSTREAM OF WET FGD SYSTEMS

    SciTech Connect

    Gary M. Blythe

    2002-10-04

    This document summarizes progress on Cooperative Agreement DE-FC26-01NT41185, Pilot Testing of Mercury Oxidation Catalysts for Upstream of Wet FGD Systems, during the time period July 1, 2002 through September 30, 2002. The objective of this project is to demonstrate at pilot scale the use of solid honeycomb catalysts to promote the oxidation of elemental mercury in the flue gas from coal combustion. The project is being funded by the U.S. DOE National Energy Technology Laboratory under Cooperative Agreement DE-FC26-01NT41185. EPRI, Great River Energy (GRE), and City Public Service (CPS) of San Antonio are project co-funders. URS Group is the prime contractor. The mercury catalytic oxidation process under development uses catalyst materials applied to honeycomb substrates to promote the oxidation of elemental mercury in the flue gas from coal-fired power plants that have wet lime or limestone flue gas desulfurization (FGD) systems. Oxidized mercury is removed in the wet FGD absorbers and co-precipitates in a stable form with the byproducts from the FGD system. The coprecipitated mercury does not appear to adversely affect the disposal or reuse properties of the FGD byproduct. The current project will test previously identified, effective catalyst materials at a larger, pilot scale and in a commercial form, so as to provide engineering data for future full-scale designs. The pilot-scale tests will continue for up to 14 months at each of two sites to provide longer-term catalyst life data. This is the fourth full reporting period for the subject Cooperative Agreement. During this period, most of the project efforts were related to completing, installing and starting up the pilot unit, completing laboratory runs to size catalysts, and procuring catalysts for the pilot unit. This technical progress report provides an update on these efforts.

  13. Pilot Testing of Mercury Oxidation Catalysts for Upstream of Wet FGD Systems

    SciTech Connect

    Gary M. Blythe

    2006-03-31

    This document summarizes progress on Cooperative Agreement DE-FC26-04NT41992, ''Pilot Testing of Mercury Oxidation Catalysts for Upstream of Wet FGD Systems'', during the time-period January 1 through March 31, 2006. The objective of this project is to demonstrate at pilot scale the use of solid honeycomb catalysts to promote the oxidation of elemental mercury in flue gas from coal combustion, and the use of a wet flue gas desulfurization (FGD) system downstream to remove the oxidized mercury at high efficiency. The project is being co-funded by the U.S. DOE National Energy Technology Laboratory, EPRI, Great River Energy (GRE), TXU Generation Company LP, the Southern Company, and Duke Energy. URS Group is the prime contractor. The mercury control process under development uses honeycomb catalysts to promote the oxidation of elemental mercury in the flue gas from coal-fired power plants that have wet lime or limestone FGD systems. Oxidized mercury is removed in the wet FGD absorbers and leaves with the byproducts from the FGD system. The current project is testing previously identified catalyst materials at pilot scale and in a commercial form to provide engineering data for future full-scale designs. The pilot-scale tests will continue for approximately 14 months or longer at each of two sites to provide longer-term catalyst life data. Pilot-scale wet FGD tests are being conducted periodically at each site to confirm the ability to scrub the catalytically oxidized mercury at high efficiency. This is the ninth reporting period for the subject Cooperative Agreement. During this period, project efforts primarily consisted of operating the catalyst pilot units at the TXU Generation Company LP's Monticello Steam Electric Station and at Georgia Power's Plant Yates. Two catalyst activity measurement trips were made to Plant Yates during the quarter. This Technical Progress Report presents catalyst activity results from the oxidation catalyst pilot unit at Plant Yates and

  14. Catalyst system and process for benzyl ether fragmentation and coal liquefaction

    DOEpatents

    Zoeller, J.R.

    1998-04-28

    Dibenzyl ether can be readily cleaved to form primarily benzaldehyde and toluene as products, along with minor amounts of bibenzyl and benzyl benzoate, in the presence of a catalyst system comprising a Group 6 metal, preferably molybdenum, a salt, and an organic halide. Although useful synthetically for the cleavage of benzyl ethers, this cleavage also represents a key model reaction for the liquefaction of coal; thus this catalyst system and process should be useful in coal liquefaction with the advantage of operating at significantly lower temperatures and pressures.

  15. Effect of plasma-catalyst system on NO removal using M-Cu (M = Mn, Ce, Cr, Co, and Fe) catalysts

    NASA Astrophysics Data System (ADS)

    Wang, Tao; Liu, Han-Zi; Yang, Bin; Sun, Bao-Min; Xiao, Hai-Ping; Zhang, Yong-Sheng

    2016-11-01

    A series of M-Cu (M = Mn, Ce, Cr, Co, and Fe) bimetal oxide catalysts combined with plasma were prepared for NO x removal at various temperatures. All catalysts combined with plasma exhibited excellent deNO x activity. The Mn-Cu catalyst showed the highest selective catalytic reduction (SCR) activity; the NO removal efficiency of the Mn-Cu catalyst could reach 90% at a gas temperature of 25 °C. E/N increased as gas temperature increased; the mean electron energy and the proportion of high-energy electrons also increased considerably, producing more active radicals. Without any catalyst, the increase in temperature inhibited NO removal owing to O3 consumption. As the temperature increased, NO removal efficiency decreased below 100 °C however, it increased in the range of 100-300 °C, and then decreased above 300 °C in the plasma-catalyst system. NO2 concentration decreased markedly at 150 °C via the fast SCR reaction.

  16. Metal-silicate catalysts: Single site, mesoporous systems without templates

    SciTech Connect

    Barnes, Craig E.; Sharp, Katherine; Albert, Austin A; Abbott, Joshua; Peretich, Michael E; Fulvio, Pasquale; Ciesielski, Peter N.; Donohoe, Bryon S.

    2015-06-01

    The textural properties of a family of silicate and mixed metal-silicate materials prepared by a nonaqueous sol-gel reaction involving the cubic silicate Si8O20(SnMe3)8 and metal chlorides MCl4 (M = Si, Ti, Zr) cross-linking reagents are described. Nitrogen adsorption isotherm data is presented and surface area and pore size distribution analyses for several examples of these materials are developed and correlated with the ratio of cross-linking reagent and the cubic silicate building block at the time of synthesis. Significant surface area and pore size distributions that shift to higher pore diameters are observed as the ratio of cross-linking reagent-to-cubic building block increases. A simple strategy for simultaneously controlling the porosity of these matrices while homogeneously dispersing identical metal centers on their surfaces for next generation catalysts is described.

  17. PILOT TESTING OF MERCURY OXIDATION CATALYSTS FOR UPSTREAM OF WET FGD SYSTEMS

    SciTech Connect

    Gary M. Blythe

    2002-07-17

    This document summarizes progress on Cooperative Agreement DE-FC26-01NT41185, Pilot Testing of Mercury Oxidation Catalysts for Upstream of Wet FGD Systems, during the time period April 1, 2002 through June 30, 2002. The objective of this project is to demonstrate at pilot scale the use of solid honeycomb catalysts to promote the oxidation of elemental mercury in the flue gas from coal combustion. The project is being funded by the U.S. DOE National Energy Technology Laboratory under Cooperative Agreement DE-FC26-01NT41185. EPRI, Great River Energy (GRE), and City Public Service (CPS) of San Antonio are project co-funders. URS Group is the prime contractor. The mercury catalytic oxidation process under development uses catalyst materials applied to honeycomb substrates to promote the oxidation of elemental mercury in the flue gas from coal-fired power plants that have wet lime or limestone flue gas desulfurization (FGD) systems. Oxidized mercury is removed in the wet FGD absorbers and co-precipitates in a stable form with the byproducts from the FGD system. The co-precipitated mercury does not appear to adversely affect the disposal or reuse properties of the FGD byproduct. The current project will test previously identified, effective catalyst materials at a larger, pilot scale and in a commercial form, so as to provide engineering data for future full-scale designs. The pilot-scale tests will continue for up to 14 months at each of two sites to provide longer-term catalyst life data. This is the third full reporting period for the subject Cooperative Agreement. During this period, most of the project efforts were related to constructing the pilot unit and conducting laboratory runs to help size catalysts for the pilot unit. This technical progress report provides an update on these two efforts.

  18. NO.sub.x catalyst and method of suppressing sulfate formation in an exhaust purification system

    DOEpatents

    Balmer-Millar, Mari Lou; Park, Paul W.; Panov, Alexander G.

    2006-08-22

    The activity and durability of a zeolite lean-bum NOx catalyst can be increased by loading metal cations on the outer surface of the zeolite. However, the metal loadings can also oxidize sulfur dioxide to cause sulfate formation in the exhaust. The present invention is a method of suppressing sulfate formation in an exhaust purification system including a NO.sub.x catalyst. The NO.sub.x catalyst includes a zeolite loaded with at least one metal. The metal is selected from among an alkali metal, an alkaline earth metal, a lanthanide metal, a noble metal, and a transition metal. In order to suppress sulfate formation, at least a portion of the loaded metal is complexed with at least one of sulfate, phosphate, and carbonate.

  19. NO.sub.x catalyst and method of suppressing sulfate formation in an exhaust purification system

    DOEpatents

    Balmer-Millar, Mari Lou; Park, Paul W.; Panov, Alexander G.

    2007-06-26

    The activity and durability of a zeolite lean-burn NOx catalyst can be increased by loading metal cations on the outer surface of the zeolite. However, the metal loadings can also oxidize sulfur dioxide to cause sulfate formation in the exhaust. The present invention is a method of suppressing sulfate formation in an exhaust purification system including a NO.sub.x catalyst. The NO.sub.x catalyst includes a zeolite loaded with at least one metal. The metal is selected from among an alkali metal, an alkaline earth metal, a lanthanide metal, a noble metal, and a transition metal. In order to suppress sulfate formation, at least a portion of the loaded metal is complexed with at least one of sulfate, phosphate, and carbonate.

  20. "Catalyst Data": Perverse Systemic Effects of Audit and Accountability in Australian Schooling

    ERIC Educational Resources Information Center

    Lingard, Bob; Sellar, Sam

    2013-01-01

    This paper examines the perverse effects of the new accountability regime central to the Labor government's national reform agenda in schooling. The focus is on National Assessment Program -- Literacy and Numeracy (NAPLAN) results that now act as "catalyst data" and are pivotal to school and system accountability. We offer a case study,…

  1. The synergistic effect in the Fe-Co bimetallic catalyst system for the growth of carbon nanotube forests

    SciTech Connect

    Hardeman, D.; Esconjauregui, S. Cartwright, R.; D'Arsié, L.; Robertson, J.; Bhardwaj, S.; Cepek, C.; Oakes, D.; Clark, J.; Ducati, C.

    2015-01-28

    We report the growth of multi-walled carbon nanotube forests employing an active-active bimetallic Fe-Co catalyst. Using this catalyst system, we observe a synergistic effect by which—in comparison to pure Fe or Co—the height of the forests increases significantly. The homogeneity in the as-grown nanotubes is also improved. By both energy dispersive spectroscopy and in-situ x-ray photoelectron spectroscopy, we show that the catalyst particles consist of Fe and Co, and this dramatically increases the growth rate of the tubes. Bimetallic catalysts are thus potentially useful for synthesising nanotube forests more efficiently.

  2. Evaluation of a novel catalyst system for producing jet fuel from whole crude shale oil. Final report 15 August 1982-31 December 1983

    SciTech Connect

    Tait, A.M.; Hensley, A.L.

    1984-02-01

    The purpose of this experimental study was to evaluate a novel catalyst system for the production of JP-4 jet fuels from a whole shale oil on a once-through basis. The dual-catalyst system consists of a pretreat catalyst specifically designed to remove nitrogen, as ammonia, from organo-nitrogen compounds, and the previously developed hydrocracking catalyst. Since hydrocracking activity is critically dependent upon almost total removal of contaminant nitrogen compounds, it was proposed that the use of the dual-catalyst system would significantly improve the process with respect to catalyst lifetimes and feed throughput.

  3. Enhancement of interfacial catalysis in a biphasic system using catalyst-binding ligands

    NASA Astrophysics Data System (ADS)

    Chaudhari, R. V.; Bhanage, B. M.; Deshpande, R. M.; Delmas, H.

    1995-02-01

    TO avoid the problem of separation of products from catalyst in homogeneous catalysis1, two-phase systems have been developed in which the catalytic complex (usually a water-soluble organo-metallic complex) remains in one (generally aqueous) phase while the products remain in a second, immiscible phase2. Catalysis relies on the transfer of organic substrates into the aqueous catalyst phase; but the limited solubility of these substrates in water leads to reaction rates much lower than those for conventional homo-geneous catalysis. Here we show that catalysis at the interface of a two-phase system can be enhanced by using a 'promoter ligand' which, although soluble in the organic phase, will bind to the organometallic catalyst and thus increase its concentration close to the interface in the aqueous phase. We demonstrate this approach for the hydroformylation of 1-octene using a rhodium-based catalyst. A rate enhancement by a factor of 10-50 is observed when we introduce the promoter ligand PPh3 in the organic phase.

  4. Method of preparing and utilizing a catalyst system for an oxidation process on a gaseous hydrocarbon stream

    DOEpatents

    Berry, David A; Shekhawat, Dushyant; Smith, Mark; Haynes, Daniel

    2013-07-16

    The disclosure relates to a method of utilizing a catalyst system for an oxidation process on a gaseous hydrocarbon stream with a mitigation of carbon accumulation. The system is comprised of a catalytically active phase deposited onto an oxygen conducting phase, with or without supplemental support. The catalytically active phase has a specified crystal structure where at least one catalytically active metal is a cation within the crystal structure and coordinated with oxygen atoms within the crystal structure. The catalyst system employs an optimum coverage ratio for a given set of oxidation conditions, based on a specified hydrocarbon conversion and a carbon deposition limit. Specific embodiments of the catalyst system are disclosed.

  5. High-throughput reactor system with individual temperature control for the investigation of monolith catalysts.

    PubMed

    Dellamorte, Joseph C; Vijay, Rohit; Snively, Christopher M; Barteau, Mark A; Lauterbach, Jochen

    2007-07-01

    A high-throughput parallel reactor system has been designed and constructed to improve the reliability of results from large diameter catalysts such as monoliths. The system, which is expandable, consists of eight quartz reactors, 23.5 mm in diameter. The eight reactors were designed with separate K type thermocouples and radiant heaters, allowing for the independent measurement and control of each reactor temperature. This design gives steady state temperature distributions over the eight reactors within 0.5 degrees C of a common setpoint from 50 to 700 degrees C. Analysis of the effluent from these reactors is performed using rapid-scan Fourier transform infrared (FTIR) spectroscopic imaging. The integration of this technique to the reactor system allows a chemically specific, truly parallel analysis of the reactor effluents with a time resolution of approximately 8 s. The capabilities of this system were demonstrated via investigation of catalyst preparation conditions on the direct epoxidation of ethylene, i.e., on the ethylene conversion and the ethylene oxide selectivity. The ethylene, ethylene oxide, and carbon dioxide concentrations were calibrated based on spectra from FTIR imaging using univariate and multivariate chemometric techniques. The results from this analysis showed that the calcination conditions significantly affect the ethylene conversion, with a threefold increase in the conversion when the catalyst was calcined for 3 h versus 12 h at 400 degrees C.

  6. A systems evaluation on the effectiveness of a catalyst retrofit program in China.

    PubMed

    Jones, M; Wilson, R; Norbeck, J M; Han, W; Hurley, R; Schuetzle, D

    2001-09-01

    A low-cost, rare-earth oxide (REO) catalyst has been recommended as part of China's retrofit program for Chinese carbureted vehicles. This study evaluated: (1) the emission reduction efficiency of the REO catalyst during chassis dynamometer testing on the FTP cycle; (2) the effect that fuel properties had on tailpipe emissions and catalyst efficiency; (3) the importance of vehicle premaintenance as part of a retrofit protocol; and (4) the emission reductions obtained following implementation of the program. Results also show that current in-use Chinese noncatalyst, carbureted vehicles operate excessively rich, resulting in extremely high emissions of CO, gaseous toxic compounds, and other non-methane hydrocarbon species (NMHC). Preretrofit maintenance alone has the potential to reduce these emissions by approximately 50%. Dynamometer emission tests showed emissions reductions of >95% for hydrocarbons, CO, and gaseous toxics after retrofit of the REO catalyst. In particular, the relative unit health risk associated with the decrease in emissions of airborne toxic compounds using unleaded Chinese fuel was reduced from 6.33 to 0.30. (Use of low-sulfur California Phase II gasoline rather than current in-use Chinese fuel reduced emissions further.) Following implementation of the program, a follow-up study showed that in-use emissions benefits were considerably less than anticipated, primarily because of poor quality control at the retrofit service centers, a less aggressive preretrofit maintenance procedure, and unauthorized modification to the recommended retrofit control system. Overall results indicate that a carefully controlled retrofit program using REO catalyst technology can reduce emissions significantly. However, well-defined implementation guidelines, and strict adherence to these guidelines are needed to achieve maximum benefits.

  7. Studying Zeolite Catalysts with a 2D Model System

    SciTech Connect

    Boscoboinik, Anibal

    2016-12-07

    Anibal Boscoboinik, a materials scientist at Brookhaven’s Center for Functional Nanomaterials, discusses the surface-science tools and 2D model system he uses to study catalysis in nanoporous zeolites, which catalyze reactions in many industrial processes.

  8. Evaluation of a novel catalyst system for producing jet fuel from whole-crude shale oil. Final report, August 1982-December 1983

    SciTech Connect

    Tait, A.M.; Hensley, A.L.

    1984-02-01

    In a previous study the development of a single-catalyst system was reported which had the unique ability to sequentially saturate, denitrogenate, and hydrocrack a whole shale oil into high yields of jet fuel on a once-through basis. Examination of the kinetics suggested that improvements in the process and in catalyst activity could be achieved by using a dual-catalyst system. The dual-catalyst system would consist of the previously developed catalyst and a pretreat catalyst specifically designed to remove nitrogen as ammonia from organo-nitrogen compounds. The increased effectiveness of the dual-catalyst system was monitored in two six-month catalyst deactivation studies using fully automated, high-pressure, fixed-bed, minipilot plants. The results indicated that use of a dual-catalyst system gave significant improvements in catalyst lifetime and unit throug hput as compared to the single-catalyst system. Dual-catalyst system lifetimes were projected at approximately 2.0 years for production of 76 wt% JP-4 fuel material from whole-crude shale oil.

  9. An Improved Catalyst System for the Pd-Catalyzed Fluorination of (Hetero)Aryl Triflates

    PubMed Central

    Buchwald, Stephen L.

    2013-01-01

    The stable Pd(0) species [(1,5-cyclooctadiene)(L•Pd)2] (L = AdBrettPhos) has been prepared and successfully evaluated as a precatalyst for the fluorination of aryl triflates derived from biologically active and heteroaryl phenols, challenging substrates for our previously reported catalyst system. Additionally, this precatalyst activates at room temperature under neutral conditions, generates 1,5-cyclooctadiene as the only byproduct, and leads to overall cleaner reaction profiles. PMID:24138611

  10. An efficient and convenient palladium catalyst system for the synthesis of amines from allylic alcohols.

    PubMed

    Banerjee, Debasis; Jagadeesh, Rajenahally V; Junge, Kathrin; Junge, Henrik; Beller, Matthias

    2012-10-01

    A novel catalyst system for efficient amination of allylic alcohols with aryl and alkyl amines is presented. By applying a convenient combination consisting of Pd(OAc)(2)/1,10-phenanthroline, a variety of allylic alcohols reacted smoothly to give the corresponding secondary and tertiary amines in good to excellent yields with high regioselectivity. The usefulness of our protocol is demonstrated in the one-step synthesis of the antifungal drug naftifine and the calcium channel blocker flunarizine.

  11. PILOT TESTING OF MERCURY OXIDATION CATALYSTS FOR UPSTREAM OF WET FGD SYSTEMS

    SciTech Connect

    Gary M. Blythe

    2002-04-26

    This document summarizes progress on Cooperative Agreement DE-FC26-01NT41185, Pilot Testing of Mercury Oxidation Catalysts for Upstream of Wet FGD Systems, during the time period January 1, 2002 through March 31, 2002. The objective of this project is to demonstrate at pilot scale the use of solid honeycomb catalysts to promote the oxidation of elemental mercury in the flue gas from coal combustion. The project is being funded by the U.S. DOE National Energy Technology Laboratory under Cooperative Agreement DE-FC26-01NT41185. EPRI, Great River Energy (GRE) and City Public Service (CPS) of San Antonio are project co-funders. URS Group is the prime contractor. The mercury catalytic oxidation process under development uses catalyst materials applied to honeycomb substrates to promote the oxidation of elemental mercury in the flue gas from coal-fired power plants that have wet lime or limestone flue gas desulfurization (FGD) systems. Oxidized mercury is removed in the wet FGD absorbers and co-precipitates in a stable form with the byproducts from the FGD system. The co-precipitated mercury does not appear to adversely affect the disposal or reuse properties of the FGD byproduct. The current project will test previously identified, effective catalyst materials at a larger, pilot scale and in a commercial form, so as to provide engineering data for future full-scale designs. The pilot-scale tests will continue for up to 14 months at each of two sites to provide longer-term catalyst life data. This is the second full reporting period for the subject Cooperative Agreement. During this period, most of the project efforts were related to pilot unit design and conducting laboratory runs to help select candidate catalysts. This technical progress report provides an update on these two efforts. A Test Plan for the upcoming pilot-scale evaluations was also prepared and submitted to NETL for review and comment. Since this document was already submitted under separate cover, this

  12. Studying Zeolite Catalysts with a 2D Model System

    ScienceCinema

    Boscoboinik, Anibal

    2016-12-14

    Anibal Boscoboinik, a materials scientist at Brookhaven’s Center for Functional Nanomaterials, discusses the surface-science tools and 2D model system he uses to study catalysis in nanoporous zeolites, which catalyze reactions in many industrial processes.

  13. PILOT TESTING OF MERCURY OXIDATION CATALYSTS FOR UPSTREAM OF WET FGD SYSTEMS

    SciTech Connect

    Gary M. Blythe

    2002-02-22

    The objective of this project is to demonstrate at pilot scale the use of solid honeycomb catalysts to promote the oxidation of elemental mercury in the flue gas from coal combustion. The project is being funded by the U.S. DOE National Energy Technology Laboratory under Cooperative Agreement DE-FC26-01NT41185. EPRI, Great River Energy (GRE), and City Public Service (CPS) of San Antonio are project co-funders. URS Group is the prime contractor. The mercury catalytic oxidation process under development uses catalyst materials applied to honeycomb substrates to promote the oxidation of elemental mercury in the flue gas from coal-fired power plants that have wet lime or limestone flue gas desulfurization (FGD) systems. Oxidized mercury is removed in the wet FGD absorbers and co-precipitates in a stable form with the byproducts from the FGD system. The co-precipitated mercury does not appear to adversely affect the disposal or reuse properties of the FGD byproduct. The current project will test previously identified, effective catalyst materials at a larger, pilot scale and in a commercial form, so as to provide engineering data for future full-scale designs. The pilot-scale tests will continue for up to 14 months at each of two sites to provide longer-term catalyst life data. This is the first full reporting period for the subject Cooperative Agreement. During this period, most of the project efforts were related to project initiation and planning. There is no significant technical progress to report for the current period.

  14. Synthesis of dimethyl ether and alternative fuels in the liquid phase from coal-derived synthesis gas. Task 2.2: Definition of preferred catalyst system; Task 2.3: Process variable scans on the preferred catalyst system; Task 2.4: Life-test on the preferred catalyst system

    SciTech Connect

    Bhatt, B.L.

    1992-09-01

    As part of the DOE-sponsored contract for the Synthesis of Dimethyl Ether (DME) and Alternative Fuels in the Liquid Phase from Coal- Derived Syngas, the single-step, slurry phase DME synthesis process was developed. The development involved screening of catalyst systems, process variable studies, and catalyst life studies in two 300 ml stirred autoclaves. As a spin-off of the Liquid Phase Methanol (LPMEOH*) process, the new process significantly improves the syngas conversion efficiency of the LPMEOH process. This improvement can be achieved by replacing a portion of methanol catalyst with a dehydration catalyst in the reactor, resulting in the product methanol being converted to DME, thus avoiding the thermodynamic equilibrium constraint of the methanol reaction. Overall, this increases syngas conversion per-pass. The selectivity and productivity of DME and methanol are affected by the catalyst system employed as well as operating conditions. A preferred catalyst system, consisting of a physical mixture of a methanol catalyst and a gamma alumina, was identified. An improvement of about 50% in methanol equivalent productivity was achieved compared to the LPMEOH process. Results from the process variable study indicate that higher pressure and CO{sub 2} removal benefit the process significantly. Limited life studies performed on the preferred catalyst system suggest somewhat higher than expected deactivation rate for the methanol catalyst. Several DME/methanol mixtures were measured for their key properties as transportation fuels. With small amounts of DME added, significant improvements in both flash points and Reid Vapor Pressure (RVP) were observed over the corresponding values of methanol alone.

  15. Development of a ruthenium/phosphite catalyst system for domino hydroformylation-reduction of olefins with carbon dioxide.

    PubMed

    Liu, Qiang; Wu, Lipeng; Fleischer, Ivana; Selent, Detlef; Franke, Robert; Jackstell, Ralf; Beller, Matthias

    2014-06-02

    An efficient domino ruthenium-catalyzed reverse water-gas-shift (RWGS)-hydroformylation-reduction reaction of olefins to alcohols is reported. Key to success is the use of specific bulky phosphite ligands and triruthenium dodecacarbonyl as the catalyst. Compared to the known ruthenium/chloride system, the new catalyst allows for a more efficient hydrohydroxymethylation of terminal and internal olefins with carbon dioxide at lower temperature. Unwanted hydrogenation of the substrate is prevented. Preliminary mechanism investigations uncovered the homogeneous nature of the active catalyst and the influence of the ligand and additive in individual steps of the reaction sequence.

  16. System and method for controlling an engine based on ammonia storage in multiple selective catalytic reduction catalysts

    SciTech Connect

    Sun, MIn; Perry, Kevin L.

    2015-11-20

    A system according to the principles of the present disclosure includes a storage estimation module and an air/fuel ratio control module. The storage estimation module estimates a first amount of ammonia stored in a first selective catalytic reduction (SCR) catalyst and estimates a second amount of ammonia stored in a second SCR catalyst. The air/fuel ratio control module controls an air/fuel ratio of an engine based on the first amount, the second amount, and a temperature of a substrate disposed in the second SCR catalyst.

  17. Pilot Testing of Mercury Oxidation Catalysts for Upstream of Wet FGD Systems

    SciTech Connect

    Gary Blythe; Conor Braman; Katherine Dombrowski; Tom Machalek

    2010-12-31

    This document is the final technical report for Cooperative Agreement DE-FC26-04NT41992, 'Pilot Testing of Mercury Oxidation Catalysts for Upstream of Wet FGD Systems,' which was conducted over the time-period January 1, 2004 through December 31, 2010. The objective of this project has been to demonstrate at pilot scale the use of solid catalysts and/or fixed-structure mercury sorbents to promote the removal of total mercury and oxidation of elemental mercury in flue gas from coal combustion, followed by wet flue gas desulfurization (FGD) to remove the oxidized mercury at high efficiency. The project was co-funded by the U.S. DOE National Energy Technology Laboratory (DOE-NETL), EPRI, Great River Energy (GRE), TXU Energy (now called Luminant), Southern Company, Salt River Project (SRP) and Duke Energy. URS Group was the prime contractor. The mercury control process under development uses fixed-structure sorbents and/or catalysts to promote the removal of total mercury and/or oxidation of elemental mercury in the flue gas from coal-fired power plants that have wet lime or limestone FGD systems. Oxidized mercury not adsorbed is removed in the wet FGD absorbers and leaves with the byproducts from the FGD system. The project has tested candidate materials at pilot scale and in a commercial form, to provide engineering data for future full-scale designs. Pilot-scale catalytic oxidation tests have been completed for periods of approximately 14 to19 months at three sites, with an additional round of pilot-scale fixed-structure sorbent tests being conducted at one of those sites. Additionally, pilot-scale wet FGD tests have been conducted downstream of mercury oxidation catalysts at a total of four sites. The sites include the two of three sites from this project and two sites where catalytic oxidation pilot testing was conducted as part of a previous DOE-NETL project. Pilot-scale wet FGD tests were also conducted at a fifth site, but with no catalyst or fixed

  18. Selective catalytic reduction system and process for treating NOx emissions using a palladium and rhodium or ruthenium catalyst

    DOEpatents

    Sobolevskiy, Anatoly; Rossin, Joseph A.; Knapke, Michael J.

    2011-07-12

    A process for the catalytic reduction of nitrogen oxides (NOx) in a gas stream (29) in the presence of H.sub.2 is provided. The process comprises contacting the gas stream with a catalyst system (38) comprising zirconia-silica washcoat particles (41), a pre-sulfated zirconia binder (44), and a catalyst combination (40) comprising palladium and at least one of rhodium, ruthenium, or a mixture of ruthenium and rhodium.

  19. Nanolithographic Fabrication and Heterogeneous Reaction Studies ofTwo-Dimensional Platinum Model Catalyst Systems

    SciTech Connect

    Contreras, Anthony Marshall

    2006-05-20

    In order to better understand the fundamental components that govern catalytic activity, two-dimensional model platinum nanocatalyst arrays have been designed and fabricated. These catalysts arrays are meant to model the interplay of the metal and support important to industrial heterogeneous catalytic reactions. Photolithography and sub-lithographic techniques such as electron beam lithography, size reduction lithography and nanoimprint lithography have been employed to create these platinum nanoarrays. Both in-situ and ex-situ surface science techniques and catalytic reaction measurements were used to correlate the structural parameters of the system to catalytic activity.

  20. Practical Aerobic Oxidations of Alcohols and Amines with Homogeneous Cu/TEMPO and Related Catalyst Systems

    PubMed Central

    Ryland, Bradford L.; Stahl, Shannon S.

    2014-01-01

    Alcohol and amine oxidations are common reactions in laboratory and industrial synthesis of organic molecules. Aerobic oxidation methods have long been sought for these transformations, but few practical methods exist that offer advantages over traditional oxidation methods. Recently developed homogeneous Cu/TEMPO (TEMPO = 2,2,6,6-tetramethylpiperidinyl-N-oxyl) and related catalyst systems appear to fill this void. The reactions exhibit high levels of chemoselectivity and broad functional-group tolerance, and they often operate efficiently at room temperature with ambient air as the oxidant. These advances, together with their historical context and recent applications, are highlighted in this minireview. PMID:25044821

  1. Strong, ductile, and thermally stable Cu-based metal-intermetallic nanostructured composites

    NASA Astrophysics Data System (ADS)

    Dusoe, Keith J.; Vijayan, Sriram; Bissell, Thomas R.; Chen, Jie; Morley, Jack E.; Valencia, Leopolodo; Dongare, Avinash M.; Aindow, Mark; Lee, Seok-Woo

    2017-01-01

    Bulk metallic glasses (BMGs) and nanocrystalline metals (NMs) have been extensively investigated due to their superior strengths and elastic limits. Despite these excellent mechanical properties, low ductility at room temperature and poor microstructural stability at elevated temperatures often limit their practical applications. Thus, there is a need for a metallic material system that can overcome these performance limits of BMGs and NMs. Here, we present novel Cu-based metal-intermetallic nanostructured composites (MINCs), which exhibit high ultimate compressive strengths (over 2 GPa), high compressive failure strain (over 20%), and superior microstructural stability even at temperatures above the glass transition temperature of Cu-based BMGs. Rapid solidification produces a unique ultra-fine microstructure that contains a large volume fraction of Cu5Zr superlattice intermetallic compound; this contributes to the high strength and superior thermal stability. Mechanical and microstructural characterizations reveal that substantial accumulation of phase boundary sliding at metal/intermetallic interfaces accounts for the extensive ductility observed.

  2. Strong, ductile, and thermally stable Cu-based metal-intermetallic nanostructured composites

    PubMed Central

    Dusoe, Keith J.; Vijayan, Sriram; Bissell, Thomas R.; Chen, Jie; Morley, Jack E.; Valencia, Leopolodo; Dongare, Avinash M.; Aindow, Mark; Lee, Seok-Woo

    2017-01-01

    Bulk metallic glasses (BMGs) and nanocrystalline metals (NMs) have been extensively investigated due to their superior strengths and elastic limits. Despite these excellent mechanical properties, low ductility at room temperature and poor microstructural stability at elevated temperatures often limit their practical applications. Thus, there is a need for a metallic material system that can overcome these performance limits of BMGs and NMs. Here, we present novel Cu-based metal-intermetallic nanostructured composites (MINCs), which exhibit high ultimate compressive strengths (over 2 GPa), high compressive failure strain (over 20%), and superior microstructural stability even at temperatures above the glass transition temperature of Cu-based BMGs. Rapid solidification produces a unique ultra-fine microstructure that contains a large volume fraction of Cu5Zr superlattice intermetallic compound; this contributes to the high strength and superior thermal stability. Mechanical and microstructural characterizations reveal that substantial accumulation of phase boundary sliding at metal/intermetallic interfaces accounts for the extensive ductility observed. PMID:28067334

  3. Catalytic and surface properties of nanocrystalline gold water gas shift catalysts

    NASA Astrophysics Data System (ADS)

    Kim, Chang Hwan

    A series of CeO2 supported gold catalysts were prepared and found to possess a high activities for the water gas shift reaction (WGS), a critical step in the production of H2 for use in petroleum refining, chemicals synthesis, and proton exchange membrane fuel cells. The deposition-precipitation method was employed in synthesizing these highly active, nanocrystalline gold catalysts. X-ray photoelectron spectroscopy (XPS), infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), and dynamic sorption analyses were performed to characterize the gold catalysts. While some of these catalysts were initially four times more active than a commercial Cu-based catalyst, they were susceptible to deactivation. Characterization using techniques including temperature programmed oxidation, XPS, and FT-IR indicated that the deactivation was caused primarily by blockage of the active sites by carbonates and/or formates. Formation of these carbonaceous species appeared to be facilitated by oxygen deficient sites on the ceria surface and may have been associated with hydroxyl groups formed on the nanocrystalline gold particles under the H2 rich conditions. The deactivation could be managed by conditioning the CeO2 surface or adding constituents to minimize oxygen deficiency. The catalytic activity was fully recovered by calcining the deactivated materials in flowing air at elevated temperatures. The gold catalyst was washcoated onto microporous Fe-Al alloy foams for use in a micro-channel WGS reactor. The performance of these coated foams was inferior to that of the powder catalyst; however, a two stage micro-channel WGS reactor employing the gold catalyst was sufficient for a 100 W fuel processor system.

  4. Selective catalytic reduction system and process for treating NOx emissions using a zinc or titanium promoted palladium-zirconium catalyst

    DOEpatents

    Sobolevskiy, Anatoly; Rossin, Joseph A.; Knapke, Michael J.

    2011-08-02

    A process and system (18) for reducing NO.sub.x in a gas using hydrogen as a reducing agent is provided. The process comprises contacting the gas stream (29) with a catalyst system (38) comprising sulfated zirconia washcoat particles (41), palladium, a pre-sulfated zirconia binder (44), and a promoter (45) comprising at least one of titanium, zinc, or a mixture thereof. The presence of zinc or titanium increases the resistance of the catalyst system to a sulfur and water-containing gas stream.

  5. Using reduced catalysts for oxidation reactions: mechanistic studies of the "Periana-Catalytica" system for CH4 oxidation.

    PubMed

    Mironov, Oleg A; Bischof, Steven M; Konnick, Michael M; Hashiguchi, Brian G; Ziatdinov, Vadim R; Goddard, William A; Ahlquist, Mårten; Periana, Roy A

    2013-10-02

    Designing oxidation catalysts based on CH activation with reduced, low oxidation state species is a seeming dilemma given the proclivity for catalyst deactivation by overoxidation. This dilemma has been recognized in the Shilov system where reduced Pt(II) is used to catalyze methane functionalization. Thus, it is generally accepted that key to replacing Pt(IV) in that system with more practical oxidants is ensuring that the oxidant does not over-oxidize the reduced Pt(II) species. The "Periana-Catalytica" system, which utilizes (bpym)Pt(II)Cl2 in concentrated sulfuric acid solvent at 200 °C, is a highly stable catalyst for the selective, high yield oxy-functionalization of methane. In lieu of the over-oxidation dilemma, the high stability and observed rapid oxidation of (bpym)Pt(II)Cl2 to Pt(IV) in the absence of methane would seem to contradict the originally proposed mechanism involving CH activation by a reduced Pt(II) species. Mechanistic studies show that the originally proposed mechanism is incomplete and that while CH activation does proceed with Pt(II) there is a solution to the over-oxidation dilemma. Importantly, contrary to the accepted view to minimize Pt(II) overoxidation, these studies also show that increasing that rate could increase the rate of catalysis and catalyst stability. The mechanistic basis for this counterintuitive prediction could help to guide the design of new catalysts for alkane oxidation that operate by CH activation.

  6. Continuous Production of Carbon-Supported Cubic and Octahedral Platinum-Based Catalysts Using Conveyor Transport System.

    PubMed

    Tsao, Kai-Chieh; Yang, Hong

    2016-09-01

    A conveyor transport system is developed for the continuous production of carbon-supported uniform Pt nanocubes, and Pt3 Ni nanocubes and octahedra in a single-reaction system under hot carbon monoxide environment. Oleylamine is critical for the high loading and even the dispersion of Pt nanocubes on a carbon support. The metal catalyst shows high performance in electrocatalytic oxidation of methanol.

  7. Efficient solar-to-fuels production from a hybrid microbial-water-splitting catalyst system.

    PubMed

    Torella, Joseph P; Gagliardi, Christopher J; Chen, Janice S; Bediako, D Kwabena; Colón, Brendan; Way, Jeffery C; Silver, Pamela A; Nocera, Daniel G

    2015-02-24

    Photovoltaic cells have considerable potential to satisfy future renewable-energy needs, but efficient and scalable methods of storing the intermittent electricity they produce are required for the large-scale implementation of solar energy. Current solar-to-fuels storage cycles based on water splitting produce hydrogen and oxygen, which are attractive fuels in principle but confront practical limitations from the current energy infrastructure that is based on liquid fuels. In this work, we report the development of a scalable, integrated bioelectrochemical system in which the bacterium Ralstonia eutropha is used to efficiently convert CO2, along with H2 and O2 produced from water splitting, into biomass and fusel alcohols. Water-splitting catalysis was performed using catalysts that are made of earth-abundant metals and enable low overpotential water splitting. In this integrated setup, equivalent solar-to-biomass yields of up to 3.2% of the thermodynamic maximum exceed that of most terrestrial plants. Moreover, engineering of R. eutropha enabled production of the fusel alcohol isopropanol at up to 216 mg/L, the highest bioelectrochemical fuel yield yet reported by >300%. This work demonstrates that catalysts of biotic and abiotic origin can be interfaced to achieve challenging chemical energy-to-fuels transformations.

  8. Efficient solar-to-fuels production from a hybrid microbial–water-splitting catalyst system

    PubMed Central

    Torella, Joseph P.; Gagliardi, Christopher J.; Chen, Janice S.; Bediako, D. Kwabena; Colón, Brendan; Way, Jeffery C.; Silver, Pamela A.; Nocera, Daniel G.

    2015-01-01

    Photovoltaic cells have considerable potential to satisfy future renewable-energy needs, but efficient and scalable methods of storing the intermittent electricity they produce are required for the large-scale implementation of solar energy. Current solar-to-fuels storage cycles based on water splitting produce hydrogen and oxygen, which are attractive fuels in principle but confront practical limitations from the current energy infrastructure that is based on liquid fuels. In this work, we report the development of a scalable, integrated bioelectrochemical system in which the bacterium Ralstonia eutropha is used to efficiently convert CO2, along with H2 and O2 produced from water splitting, into biomass and fusel alcohols. Water-splitting catalysis was performed using catalysts that are made of earth-abundant metals and enable low overpotential water splitting. In this integrated setup, equivalent solar-to-biomass yields of up to 3.2% of the thermodynamic maximum exceed that of most terrestrial plants. Moreover, engineering of R. eutropha enabled production of the fusel alcohol isopropanol at up to 216 mg/L, the highest bioelectrochemical fuel yield yet reported by >300%. This work demonstrates that catalysts of biotic and abiotic origin can be interfaced to achieve challenging chemical energy-to-fuels transformations. PMID:25675518

  9. Incorporation of Water-Oxidation Catalysts into Photoinduced Electron Transfer Systems: Toward Solar Fuel Generation via Artificial Photosynthesis

    NASA Astrophysics Data System (ADS)

    Vagnini, Michael Thomas

    mechanisms and probing highly-reactive intermediates, and it also establishes a basis in systems design for photodriving catalytic processes. Covalent dye-catalyst assemblies have been gaining recognition as a useful motif for incorporation into dye-sensitized photoanodes for photoelectrochemical water-splitting cells, and the PMI-Ir catalyst unit is well-poised, both in the energetics and kinetics of its electron transfer properties, to improve upon current solar-driven fuel-forming devices.

  10. Copper(I)/ABNO-catalyzed aerobic alcohol oxidation: alleviating steric and electronic constraints of Cu/TEMPO catalyst systems.

    PubMed

    Steves, Janelle E; Stahl, Shannon S

    2013-10-23

    Cu/TEMPO catalyst systems promote efficient aerobic oxidation of sterically unhindered primary alcohols and electronically activated substrates, but they show reduced reactivity with aliphatic and secondary alcohols. Here, we report a catalyst system, consisting of ((MeO)bpy)Cu(I)(OTf) and ABNO ((MeO)bpy = 4,4'-dimethoxy-2,2'-bipyridine; ABNO = 9-azabicyclo[3.3.1]nonane N-oxyl), that mediates aerobic oxidation of all classes of alcohols, including primary and secondary allylic, benzylic, and aliphatic alcohols with nearly equal efficiency. The catalyst exhibits broad functional group compatibility, and most reactions are complete within 1 h at room temperature using ambient air as the source of oxidant.

  11. Ab initio investigation on hydrogen adsorption capability in Zn and Cu-based metal organic frameworks

    NASA Astrophysics Data System (ADS)

    Tanuwijaya, V. V.; Hidayat, N. N.; Agusta, M. K.; Dipojono, H. K.

    2015-09-01

    One of the biggest challenge in material technology for hydrogen storage application is to increase hydrogen uptake in room temperature and pressure. As a class of highly porous material, Metal-Organic Frameworks (MOF) holds great potential with its tunable structure. However, little is known about the effect of metal cluster to its hydrogen storage capability. Investigation on this matter has been carried out carefully on small cluster of Zn and Cu-based MOF using first principles method. The calculation of two distinct building units of MOFs, namely octahedral and paddle-wheel models, have been done with B3LYP density functional method using 6-31G(d,p) and LANL2DZ basis sets. From geometry optimization of Zn-based MOF linked by benzene-dicarboxylate (MOF-5), it is found that hydrogen tends to keep distance from metal cluster group and stays above benzene ring. In the other hand, hydrogen molecule prefers to stay atop of the exposed Cu atom in Cu-based MOF system linked by the same linker group (Cu-bdc). Calculated hydrogen binding enthalpies for Zn and Cu octahedral cages at ZnO3 sites are 1.64kJ/mol and 2.73kJ/mol respectively, while hydrogen binding enthalpies for Zn and Cu paddle-wheel cages calculated on top of metal atoms are found to be at 6.05kJ/mol and 6.10kJ/mol respectively. Major difference between Zn-MOF-5 and Cu-bdc hydrogen uptake performance might be caused by unsaturated metal sites present in Cu-bdc system and the influence of their geometric structures, although a small difference on binding energy in the type of transition metal used is also observed. The comparison between Zn and Cu-based MOF may contribute to a comprehensive understanding of metal clusters and the importance of selecting best transition metal for design and synthesis of metal-organic frameworks.

  12. Ab initio investigation on hydrogen adsorption capability in Zn and Cu-based metal organic frameworks

    SciTech Connect

    Tanuwijaya, V. V.; Hidayat, N. N. Agusta, M. K. Dipojono, H. K.

    2015-09-30

    One of the biggest challenge in material technology for hydrogen storage application is to increase hydrogen uptake in room temperature and pressure. As a class of highly porous material, Metal-Organic Frameworks (MOF) holds great potential with its tunable structure. However, little is known about the effect of metal cluster to its hydrogen storage capability. Investigation on this matter has been carried out carefully on small cluster of Zn and Cu-based MOF using first principles method. The calculation of two distinct building units of MOFs, namely octahedral and paddle-wheel models, have been done with B3LYP density functional method using 6-31G(d,p) and LANL2DZ basis sets. From geometry optimization of Zn-based MOF linked by benzene-dicarboxylate (MOF-5), it is found that hydrogen tends to keep distance from metal cluster group and stays above benzene ring. In the other hand, hydrogen molecule prefers to stay atop of the exposed Cu atom in Cu-based MOF system linked by the same linker group (Cu-bdc). Calculated hydrogen binding enthalpies for Zn and Cu octahedral cages at ZnO{sub 3} sites are 1.64kJ/mol and 2.73kJ/mol respectively, while hydrogen binding enthalpies for Zn and Cu paddle-wheel cages calculated on top of metal atoms are found to be at 6.05kJ/mol and 6.10kJ/mol respectively. Major difference between Zn-MOF-5 and Cu-bdc hydrogen uptake performance might be caused by unsaturated metal sites present in Cu-bdc system and the influence of their geometric structures, although a small difference on binding energy in the type of transition metal used is also observed. The comparison between Zn and Cu-based MOF may contribute to a comprehensive understanding of metal clusters and the importance of selecting best transition metal for design and synthesis of metal-organic frameworks.

  13. Surface chemistry and catalytic properties of VOX/Ti-MCM-41 catalysts for dibenzothiophene oxidation in a biphasic system

    NASA Astrophysics Data System (ADS)

    González, J.; Chen, L. F.; Wang, J. A.; Manríquez, Ma.; Limas, R.; Schachat, P.; Navarrete, J.; Contreras, J. L.

    2016-08-01

    A series of vanadium oxide supported on Ti-MCM-41 catalysts was synthesized via the incipient impregnation method by varying the vanadia loading from 5 wt% to 10, 15, 20 and 25 wt%. These catalysts were characterized by a variety of advanced techniques for investigating their crystalline structure, textural properties, and surface chemistry information including surface acidity, reducibility, vanadium oxidation states, and morphological features. The catalytic activities of the catalysts were evaluated in a biphasic reaction system for oxidative desulfurization (ODS) of a model diesel containing 300 ppm of dibenzothiophene (DBT) where acetonitrile was used as extraction solvent and H2O2 as oxidant. ODS activity was found to be proportional to the V5+/(V4+ + V5+) values of the catalysts, indicating that the surface vanadium pentoxide (V2O5) was the active phase. Reaction temperature would influence significantly the ODS efficiency; high temperature, i.e., 80 °C, would lead to low ODS reaction due to the partial decomposition of oxidant. All the catalysts contained both Lewis and Brønsted acid sites but the former was predominant. The catalysts with low vanadia loading (5 or 10 wt%V2O5) had many Lewis acid sites and could strongly adsorb DBT molecule via the electron donation/acceptance action which resulted in an inhibition for the reaction of DBT with the surface peroxometallic species. The catalyst with high vanadia loading (25wt%V2O5/Ti-MCM-41) showed the highest catalytic activity and could remove 99.9% of DBT at 60 °C within 60 min.

  14. Glass formation, chemical properties and surface analysis of Cu-based bulk metallic glasses.

    PubMed

    Qin, Chunling; Zhao, Weimin; Inoue, Akihisa

    2011-01-01

    This paper reviews the influence of alloying elements Mo, Nb, Ta and Ni on glass formation and corrosion resistance of Cu-based bulk metallic glasses (BMGs). In order to obtain basic knowledge for application to the industry, corrosion resistance of the Cu-Hf-Ti-(Mo, Nb, Ta, Ni) and Cu-Zr-Ag-Al-(Nb) bulk glassy alloy systems in various solutions are reported in this work. Moreover, X-ray photoelectron spectroscopy (XPS) analysis is performed to clarify the surface-related chemical characteristics of the alloy before and after immersion in the solutions; this has lead to a better understanding of the correlation between the surface composition and the corrosion resistance.

  15. Perfectly alternating copolymerization of CO2 and epichlorohydrin using cobalt(III)-based catalyst systems.

    PubMed

    Wu, Guang-Peng; Wei, Sheng-Hsuan; Ren, Wei-Min; Lu, Xiao-Bing; Xu, Tie-Qi; Darensbourg, Donald J

    2011-09-28

    Selective transformations of carbon dioxide and epoxides into biodegradable polycarbonates by the alternating copolymerization of the two monomers represent some of the most well-studied and innovative technologies for potential large-scale utilization of carbon dioxide in chemical synthesis. For the most part, previous studies of these processes have focused on the use of aliphatic terminal epoxides or cyclohexene oxide derivatives, with only rare reports concerning the synthesis of CO(2) copolymers from epoxides containing electron-withdrawing groups such as styrene oxide. Herein we report the production of the CO(2) copolymer with more than 99% carbonate linkages from the coupling of CO(2) with epichlorohydrin, employing binary and bifunctional (salen)cobalt(III)-based catalyst systems. Comparative kinetic studies were performed via in situ infrared measurements as a function of temperature to assess the activation barriers for the production of cyclic carbonate versus copolymer involving two electronically different epoxides: epichlorohydrin and propylene oxide. The relative small activation energy difference between copolymer versus cyclic carbonate formation for the epichlorohydrin/CO(2) process (45.4 kJ/mol) accounts in part for the selective synthesis of copolymer to be more difficult in comparison with the propylene oxide/CO(2) case (53.5 kJ/mol). Direct observation of the propagating polymer-chain species from the binary (salen)CoX/MTBD (X = 2,4-dinitrophenoxide and MTBD = 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene) catalyst system by means of electrospray ionization mass spectrometry confirmed the perfectly alternating nature of the copolymerization process. This observation in combination with control experiments suggests possible intermediates involving MTBD in the CO(2)/epichlorohydrin copolymerization process.

  16. Molecular Photocatalytic Systems for Solar Energy Conversion: Catalysts for the Evolution of Hydrogen and Oxygen from Water

    NASA Astrophysics Data System (ADS)

    Zamaraev, Kirill I.; Parmon, Valentin N.

    1983-09-01

    This review is devoted to recent advances in the development and study of homogeneous and heterogeneous catalysts for the reduction of water to molecular hydrogen and its oxidation to molecular oxygen. The production of micro-heterogeneous systems for photocatalytic charge separation is also discussed. 114 references.

  17. Reformer assisted lean NO.sub.x catalyst aftertreatment system and method

    DOEpatents

    Kalyanaraman, Mohan; Park, Paul W.; Ragle, Christie S.

    2010-06-29

    A method and apparatus for catalytically processing a gas stream passing therethrough to reduce the presence of NO.sub.x therein, wherein the apparatus includes a first catalyst composed of a silver-containing alumina that is adapted for catalytically processing the gas stream at a first temperature range, a second catalyst composed of a copper-containing zeolite located downstream from the first catalyst, wherein the second catalyst is adapted for catalytically processing the gas stream at a lower second temperature range relative to the first temperature range, a hydrocarbon compound for injection into the gas stream upstream of the first catalyst to provide a reductant, and a reformer for reforming a portion of the hydrocarbon compound into H.sub.2 and/or oxygenated hydrocarbon for injection into the gas stream upstream of the first catalyst. The second catalyst is adapted to facilitate the reaction of reducing NOx into N.sub.2, whereby the intermediates are produced via the first catalyst reacting with NOx and hydrocarbons.

  18. Effects of particulates, heavy metals and acid gas on the removals of NO and PAHs by V2O5-WO3 catalysts in waste incineration system.

    PubMed

    Chang, Feng-Yim; Chen, Jyh-Cherng; Wey, Ming-Yen; Tsai, Shih-An

    2009-10-15

    This study investigated the activities of prepared and commercial V(2)O(5)-WO(3) catalysts for simultaneous removals of NO and polycyclic aromatic hydrocarbons (PAHs) and the influences of particulates, heavy metals, SO(2), and HCl on the performances of catalysts. The experiments were carried out in a laboratory-scale waste incineration system equipped with a catalyst reactor. The DREs of PAHs by prepared and commercial V(2)O(5)-WO(3) catalysts were 64% and 72%, respectively. Increasing the particulate concentrations in flue gas suppressed the DRE of PAHs, but increasing the carbon content on surface of catalysts promotes the NO conversions. The DRE of PAHs by the catalysts was significantly decreased by the increased concentrations of heavy metal Cd, but was promoted by high concentration of Pb. The influence level of SO(2) was higher than HCl on the performances of V(2)O(5)-WO(3) catalysts for PAHs removal, but was lower than HCl for NO removal. Prepared and commercial V(2)O(5)-WO(3) catalysts have similar trends on the effects of particulates, heavy metals, SO(2), and HCl. The results of ESCA analysis reveal that the presence of these pollutants on the surface of catalysts did not change the chemical state of V and W.

  19. A simple and effective catalytic system for epoxidation of aliphatic terminal alkenes with manganese(II) as the catalyst.

    PubMed

    Ho, Kam-Piu; Wong, Wing-Leung; Lam, Kin-Ming; Lai, Cheuk-Piu; Chan, Tak Hang; Wong, Kwok-Yin

    2008-01-01

    A simple catalytic system that uses commercially available manganese(II) perchlorate as the catalyst and peracetic acid as the oxidant is found to be very effective in the epoxidation of aliphatic terminal alkenes with high product selectivity at ambient temperature. Many terminal alkenes are epoxidised efficiently on a gram scale in less than an hour to give excellent yields of isolated product (>90 %) of epoxides in high purity. Kinetic studies with some C9-alkenes show that the catalytic system is more efficient in epoxidising terminal alkenes than internal alkenes, which is contrary to most commonly known epoxidation systems. The reaction rate for epoxidation decreases in the order: 1-nonene>cis-3-nonene>trans-3-nonene. ESI-MS and EPR spectroscopic studies suggest that the active form of the catalyst is a high-valent oligonuclear manganese species, which probably functions as the oxygen atom-transfer agent in the epoxidation reaction.

  20. Polypyrrole-functionalized ruthenium carbene catalysts as efficient heterogeneous systems for olefin epoxidation.

    PubMed

    Dakkach, Mohamed; Fontrodona, Xavier; Parella, Teodor; Atlamsani, Ahmed; Romero, Isabel; Rodríguez, Montserrat

    2014-07-14

    New Ru complexes containing the bpea-pyr ligand (bpea-pyr stands for N,N-bis(pyridin-2-ylmethyl)-3-(1H-pyrrol-1-yl)propan-1-amine), with the formula [RuCl2(bpea-pyr)(dmso)] (isomeric complexes 2a and 2b) or [Ru(CN-Me)(bpea-pyr)X)](n+) (CN-Me = 3-methyl-1-(pyridin-2-yl)-1H-imidazol-3-ium-2-ide; X = Cl, 3, or X = H2O, 4), have been prepared and fully characterized. Complexes 3 and 4 have been anchored onto an electrode surface through electropolymerization of the attached pyrrole group, yielding stable polypyrrole films. The electrochemical behaviour of 4, which displays a bielectronic Ru(IV/II) redox pair in solution, is dramatically affected by the electropolymerization process leading to the occurrence of two monoelectronic Ru(IV/III) and Ru(III/II) redox pairs in the heterogeneous system. A carbon felt modified electrode containing complex 4 (C-felt/poly-4) has been evaluated as a heterogeneous catalyst in the epoxidation of various olefin substrates using PhI(OAc)2 as an oxidant, displaying TON values of several thousands in all cases and good selectivity for the epoxide product.

  1. Orthogonal Cu- and Pd-Based Catalyst Systems for the O- and N-Arylation of Aminophenols

    PubMed Central

    Maiti, Debabrata; Buchwald, Stephen L.

    2009-01-01

    O- or N-arylated aminophenol products constitute a common structural motif in various potentially useful therapeutic agents and/or drug candidates. We have developed a complementary set of Cu- and Pd-based catalyst systems for the selective O- and N-arylation of unprotected aminophenols using aryl halides. Selective O-arylation of 3- and 4-aminophenols is achieved with copper-catalyzed methods employing picolinic acid or CyDMEDA, trans-N,N′-dimethyl-1,2-cyclohexanediamine, respectively, as the ligand. The selective formation of N-arylated products of 3- and 4-aminophenols can be obtained with BrettPhos precatalyst, a biarylmonophosphine-based palladium catalyst. 2-Aminophenol can be selectively N-arylated with CuI, although no system for the selective O-arylation could be found. Coupling partners with diverse electronic properties and a variety of functional groups can be selectively transformed under these conditions. PMID:19899753

  2. Catalyst separation method reduces Platformer turnaround costs

    SciTech Connect

    Blashka, S.R.; Welch, J.G.; Nite, K.; Furfaro, A.P.

    1995-09-18

    A catalyst separation technology that segregates catalyst particles by density has proved successful in recovering CCR (continuous catalyst regeneration) Platforming catalyst that had been contaminated with heel catalyst, non-flowing catalyst. UOP`s CCR Platforming process converts naphtha to high-octane gasoline components and aromatics for petrochemical use. The reforming reactions take place in a series of Platforming reactors loaded with platinum-containing reforming catalyst. CCR Platforming technology incorporates a moving catalyst bed in a system that permits addition and withdrawal of catalyst from the reactor while the unit is operating. As the catalyst circulates through the reactors, it builds up typical carbon levels of 5%. Over time, the heel catalyst will build up carbon levels as high as 50%. When the catalyst is unloaded, heel catalyst is released, contaminating the last fraction of catalyst removed from the reactor. The heel-contaminated catalyst should not be reused because only a small fraction of the carbon on the heel catalyst is removed in the regeneration section. If returned to inventory, the carbon would react rapidly, causing temperature excursions. If heel-contaminated catalyst is reused, there is a high potential for damage to the unit. Density grading was used, after ex situ regeneration to recover the uncontaminated catalyst for reuse.

  3. Advanced cathode materials for polymer electrolyte fuel cells based on pt/ metal oxides: from model electrodes to catalyst systems.

    PubMed

    Fabbri, Emiliana; Pătru, Alexandra; Rabis, Annett; Kötz, Rüdiger; Schmidt, Thomas J

    2014-01-01

    The development of stable catalyst systems for application at the cathode side of polymer electrolyte fuel cells (PEFCs) requires the substitution of the state-of-the-art carbon supports with materials showing high corrosion resistance in a strongly oxidizing environment. Metal oxides in their highest oxidation state can represent viable support materials for the next generation PEFC cathodes. In the present work a multilevel approach has been adopted to investigate the kinetics and the activity of Pt nanoparticles supported on SnO2-based metal oxides. Particularly, model electrodes made of SnO2 thin films supporting Pt nanoparticles, and porous catalyst systems made of Pt nanoparticles supported on Sb-doped SnO2 high surface area powders have been investigated. The present results indicate that SnO2-based supports do not modify the oxygen reduction reaction mechanism on the Pt nanoparticle surface, but rather lead to catalysts with enhanced specific activity compared to Pt/carbon systems. Different reasons for the enhancement in the specific activity are considered and discussed.

  4. Modified Fe3O4- hydroxyapatite nanocomposites as heterogeneous catalysts in three UV, Vis and Fenton like degradation systems

    NASA Astrophysics Data System (ADS)

    Valizadeh, S.; Rasoulifard, M. H.; Dorraji, M. S. Seyed

    2014-11-01

    The magnetite-hydroxyapatite (M-HAP) nanocomposites were prepared by a chemical co- precipitation procedure and characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and diffuse reflectance spectra (DRS). The ability of the synthesized catalyst for photocatalytic degradation of Acid Blue 25 (AB25), as an organic dye, under UV irradiation was studied. The catalyst was modified employing transition metals (Mn, Fe, Co, Ni, Cu and Zn) trying to improve the catalytic performance of HAP in absence of UV irradiation and in the presence of hydrogen peroxide i.e. a Fenton like reaction. The best results obtained for Cu and Co modified M-HAPs and the effect of operational parameters such pH, amount of catalyst and hydrogen peroxide concentration was studied. In order to investigate the performance of HAP based photocatalyst in visible light region, M-HAP was modified with silver ions. At the end, Langmuir-Hinshelwood kinetic expression used to evaluate and compare the catalytic systems. The strongest degradation activity was observed for Ag-M-HAP/Vis system because of Ag3PO4 formation. Apparent reaction rate constant (Kapp) by Ag-M-HAP/Vis was 63, 36 and 19 times faster than Cu-M-HAP(II)/H2O2, Co-M-HAP(II)/H2O2 and M-HAP (I)/UV systems, respectively.

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

    SciTech Connect

    T. Brent Gunnoe

    2011-02-17

    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

  6. Assessment of microcapsule—catalyst particles healing system in high performance fibre reinforced polymer composite

    NASA Astrophysics Data System (ADS)

    Bolimowski, P. A.; Wass, D. F.; Bond, I. P.

    2016-08-01

    Autonomous self-healing in carbon fibre reinforced polymer (CFRP) is demonstrated using epoxy resin filled microcapsules and a solid-state catalyst. Microcapsules filled with oligomeric epoxy resin (20-450 μm) and particles of Sc(OTf)3 are embedded in an interleave region of a unidirectional CFRP laminate and tested under mode I loading. Double cantilever beam (DCB) test specimens containing variable concentrations of microcapsules and catalyst were prepared, tested and compared to those healed by manual injection with corresponding healing resin formulation. The healing efficiency was evaluated by comparing the maximum peak load recorded on load-displacement curves for pristine and healed specimens. A 44% maximum recovery was observed for specimens containing 10 wt% of solid phase catalyst and 11 wt% of epoxy microcapsules. However, a significant (80%) decrease in initial strain energy release rate (G IC) was observed for specimens with the embedded healing chemistries.

  7. Tuning the properties of copper-based catalysts based on molecular in situ studies of model systems.

    PubMed

    Stacchiola, Darío J

    2015-07-21

    Studying catalytic processes at the molecular level is extremely challenging, due to the structural and chemical complexity of the materials used as catalysts and the presence of reactants and products in the reactor's environment. The most common materials used on catalysts are transition metals and their oxides. The importance of multifunctional active sites at metal/oxide interfaces has been long recognized, but a molecular picture of them based on experimental observations is only recently emerging. The initial approach to interrogate the surface chemistry of catalysts at the molecular level consisted of studying metal single crystals as models for reactive metal centers, moving later to single crystal or well-defined thin film oxides. The natural next iteration consisted in the deposition of metal nanoparticles on well-defined oxide substrates. Metal nanoparticles contain undercoordinated sites, which are more reactive. It is also possible to create architectures where oxide nanoparticles are deposited on top of metal single crystals, denominated inverse catalysts, leading in this case to a high concentration of reactive cationic sites in direct contact with the underlying fully coordinated metal atoms. Using a second oxide as a support (host), a multifunctional configuration can be built in which both metal and oxide nanoparticles are located in close proximity. Our recent studies on copper-based catalysts are presented here as an example of the application of these complementary model systems, starting from the creation of undercoordinated sites on Cu(111) and Cu2O(111) surfaces, continuing with the formation of mixed-metal copper oxides, the synthesis of ceria nanoparticles on Cu(111) and the codeposition of Cu and ceria nanoparticles on TiO2(110). Catalysts have traditionally been characterized before or after reactions and analyzed based on static representations of surface structures. It is shown here how dynamic changes on a catalyst's chemical state

  8. A highly versatile catalyst system for the cross-coupling of aryl chlorides and amines.

    PubMed

    Lundgren, Rylan J; Sappong-Kumankumah, Antonia; Stradiotto, Mark

    2010-02-08

    The syntheses of 2-(di-tert-butylphosphino)-N,N-dimethylaniline (L1, 71%) and 2-(di-1-adamantylphosphino)-N,N-dimethylaniline (L2, 74 %), and their application in Buchwald-Hartwig amination, are reported. In combination with [Pd(allyl)Cl](2) or [Pd(cinnamyl)Cl](2), these structurally simple and air-stable P,N ligands enable the cross-coupling of aryl and heteroaryl chlorides, including those bearing as substituents enolizable ketones, ethers, esters, carboxylic acids, phenols, alcohols, olefins, amides, and halogens, to a diverse range of amine and related substrates that includes primary alkyl- and arylamines, cyclic and acyclic secondary amines, N-H imines, hydrazones, lithium amide, and ammonia. In many cases, the reactions can be performed at low catalyst loadings (0.5-0.02 mol % Pd) with excellent functional group tolerance and chemoselectivity. Examples of cross-coupling reactions involving 1,4-bromochlorobenzene and iodobenzene are also reported. Under similar conditions, inferior catalytic performance was achieved when using Pd(OAc)(2), PdCl(2), [PdCl(2)(cod)] (cod = 1,5-cyclooctadiene), [PdCl(2)(MeCN)(2)], or [Pd(2)(dba)(3)] (dba = dibenzylideneacetone) in combination with L1 or L2, or by use of [Pd(allyl)Cl](2) or [Pd(cinnamyl)Cl](2) with variants of L1 and L2 bearing less basic or less sterically demanding substituents on phosphorus or lacking an ortho-dimethylamino fragment. Given current limitations associated with established ligand classes with regard to maintaining high activity across the diverse possible range of C-N coupling applications, L1 and L2 represent unusually versatile ligand systems for the cross-coupling of aryl chlorides and amines.

  9. Enhanced High- and Low-Temperature Performance of NOx Reduction Catalyst Materials

    SciTech Connect

    Gao, Feng; Muntean, George G.; Peden, Charles HF; Howden, Ken; Currier, Neal; Kamasamudram, Krishna; Kumar, Ashok; Li, Junhui; Luo, Jinyong; Stafford, Randy; Yezerets, Aleksey; Castagnola, Mario; Chen, Hai-Ying; Hess, Howard ..

    2014-12-09

    In this annual CRADA program report, we will briefly highlight results from our recent studies of the stability of candidate K-based high temperature NSR materials, and comparative studies of low temperature performance of SSZ-13 and SAPO-34 CHA catalysts; in particular, recent results comparing Fe- and Cu-based CHA materials.

  10. Bimetallic Catalysts.

    ERIC Educational Resources Information Center

    Sinfelt, John H.

    1985-01-01

    Chemical reaction rates can be controlled by varying composition of miniscule clusters of metal atoms. These bimetallic catalysts have had major impact on petroleum refining, where work has involved heterogeneous catalysis (reacting molecules in a phase separate from catalyst.) Experimentation involving hydrocarbon reactions, catalytic…

  11. Oxyhydrochlorination catalyst

    DOEpatents

    Taylor, Charles E.; Noceti, Richard P.

    1992-01-01

    An improved catalyst and method for the oxyhydrochlorination of methane is disclosed. The catalyst includes a pyrogenic porous support on which is layered as active material, cobalt chloride in major proportion, and minor proportions of an alkali metal chloride and of a rare earth chloride. On contact of the catalyst with a gas flow of methane, HCl and oxygen, more than 60% of the methane is converted and of that converted more than 40% occurs as monochloromethane. Advantageously, the monochloromethane can be used to produce gasoline boiling range hydrocarbons with the recycle of HCl for further reaction. This catalyst is also of value for the production of formic acid as are analogous catalysts with lead, silver or nickel chlorides substituted for the cobalt chloride.

  12. High-Activity Dealloyed Catalysts

    SciTech Connect

    Kongkanand, Anusorn

    2014-09-30

    Reduction of costly Pt usage in proton exchange membrane fuel cell electrodes is one of the major challenges towards development and commercialization of fuel cell vehicles. Although few have met the initial-kinetic activity requirements in a realistic fuel cell device, no catalyst material has ever met the demanding fuel cell durability targets set by DOE. In this project, a team of 4 universities and 2 companies came together to investigate a concept that appeared promising in preliminary non-fuel cell tests then to further develop the catalyst to a mature level ready for vehicle implementation. The team consists of academia with technical leadership in their respective areas, a catalyst supplier, and a fuel cell system integrator.The tightly collaborative project enabled development of a highly active and durable catalyst with performance that significantly exceeds that of previous catalysts and meets the DOE targets for the first time (Figure 1A). The catalyst was then further evaluated in full-active-area stack in a realistic vehicle operating condition (Figure 1B). This is the first public demonstration that one can realize the performance benefit and Pt cost reduction over a conventional pure Pt catalyst in a long-term realistic PEMFC system. Furthermore, systematic analyses of a range of catalysts with different performance after fuel cell testing allowed for correlation between catalyst microstructure and its electrocatalytic activity and durability. This will in turn aid future catalyst development.

  13. Key structure-activity relationships in the vanadium phosphorus oxide catalyst system

    SciTech Connect

    Thompson, M.R. ); Ebner, J.R. )

    1990-04-01

    The crystal structure of vanadyl pyrophosphate has been redetermined using single crystals obtained from a near solidified melt of a microcrystalline catalyst sample. Crystals that index as vanadyl pyrophosphate obtained from this melt are variable in color. Crystallographic refinement of the single crystal x-ray diffraction data indicates that structural differences among these materials can be described in terms of crystal defects associated with linear disorder of the vanadium atoms. The importance of the disorder is outlined in the context of its effect on the proposed surface topology parallel to (1,0,0). Models of the surface topology simply and intuitively account for the non-stoichometric surface atomic P/V ratio exhibited by selective catalysts of this phase. These models also point to the possible role of the excess phosphorus in providing site isolation of reactive centers at the surface. 33 refs., 7 figs.

  14. Experimental reactor system for investigation of indirect liquefaction catalysts in slurry phase operation

    SciTech Connect

    Zarochak, M.F.; Pennline, H.W.; Schehl, R.R.

    1984-02-01

    A detailed description of the slurry (three-phase) reactor scheme employed at the Pittsburgh Energy Technology Center for Fischer-Tropsch synthesis is reported. Emphasis is placed on materials of construction, equipment operation, and product collection and analysis. The unit's functional limits and safety features are also provided. Operational problems and the resolving remedial action are discussed. The reactor scheme now operates such that near isothermal conditions exist over the reactor internal length. Thus, with excellent temperature control assured, reliable information for evaluation of potential catalyst candidates for slurry phase Fischer-Tropsch synthesis is possible within a wide range of operating conditions. Test results with a fused-iron catalyst suspended in a paraffinic liquid medium are given as an example.

  15. SU-E-T-350: Verification of Gating Performance of a New Elekta Gating Solution: Response Kit and Catalyst System

    SciTech Connect

    Xie, X; Cao, D; Housley, D; Mehta, V; Shepard, D

    2014-06-01

    Purpose: In this work, we have tested the performance of new respiratory gating solutions for Elekta linacs. These solutions include the Response gating and the C-RAD Catalyst surface mapping system.Verification measurements have been performed for a series of clinical cases. We also examined the beam on latency of the system and its impact on delivery efficiency. Methods: To verify the benefits of tighter gating windows, a Quasar Respiratory Motion Platform was used. Its vertical-motion plate acted as a respiration surrogate and was tracked by the Catalyst system to generate gating signals. A MatriXX ion-chamber array was mounted on its longitudinal-moving platform. Clinical plans are delivered to a stationary and moving Matrix array at 100%, 50% and 30% gating windows and gamma scores were calculated comparing moving delivery results to the stationary result. It is important to note that as one moves to tighter gating windows, the delivery efficiency will be impacted by the linac's beam-on latency. Using a specialized software package, we generated beam-on signals of lengths of 1000ms, 600ms, 450ms, 400ms, 350ms and 300ms. As the gating windows get tighter, one can expect to reach a point where the dose rate will fall to nearly zero, indicating that the gating window is close to beam-on latency. A clinically useful gating window needs to be significantly longer than the latency for the linac. Results: As expected, the use of tighter gating windows improved delivery accuracy. However, a lower limit of the gating window, largely defined by linac beam-on latency, exists at around 300ms. Conclusion: The Response gating kit, combined with the C-RAD Catalyst, provides an effective solution for respiratorygated treatment delivery. Careful patient selection, gating window design, even visual/audio coaching may be necessary to ensure both delivery quality and efficiency. This research project is funded by Elekta.

  16. Design and synthesis of a new type of ferrocene-based planar chiral DMAP analogues. A new catalyst system for asymmetric nucleophilic catalysis.

    PubMed

    Seitzberg, Jimmi Gerner; Dissing, Carsten; Søtofte, Inger; Norrby, Per-Ola; Johannsen, Mogens

    2005-10-14

    A new first-generation catalyst system for nucleophilic catalysis has been developed. It is based on a planar chiral ferrocene skeleton with either the potent nucleophile 4-(dimethylamino)pyridine (DMAP) or the related 4-nitropyridine N-oxide attached in either the 2- or the 3-position. The syntheses are short, efficient, and enantioselective and X-ray crystal structures of both DMAP-derived catalysts are presented. The DMAP-based catalysts were tested in asymmetric reactions and the 3-derivative 14 showed good activity and a moderate level of enantioselectivity. The sense of induction (selectivity) was studied using molecular modeling and the results pointed at new directions for future generations of catalysts based on this design.

  17. Evaluation of PEMFC System Contaminants on the Performance of Pt Catalyst via Cyclic Voltammetry: Preprint

    SciTech Connect

    Wang, H.; Macomber, C.; Dinh, H. N.

    2012-07-01

    Using electrochemical cyclic voltammetry as a quick ex-situ screening tool, the impact of the extracted solution and the individual leachable constituents from prospective BOP component materials on the performance and recoverability of the platinum catalyst were evaluated. Taking an extract from Zytel{trademark} HTN51G35HSLR (PPA) as an example, the major leachable organic components are caprolactam and 1,6 hexanediol. While these organic compounds by themselves do poison the Pt catalyst to some extent, such influence is mostly recoverable by means of potential holding and potential cycling. The extracted solution, however, shows a more drastic poisoning effect and it was not recoverable. Therefore the non-recoverable poisoning effect observed for the extracted solution is not from the two organic species studied. This demonstrates the complexity of such a contaminant study. Inorganic compounds that are known poisons like sulfur even in very low concentrations, may have a more dominant effect on the Pt catalyst and the recoverability.

  18. Catalyst mixtures

    DOEpatents

    Masel, Richard I.; Rosen, Brian A.

    2017-02-14

    Catalysts that include at least one catalytically active element and one helper catalyst can be used to increase the rate or lower the overpotential of chemical reactions. The helper catalyst can simultaneously act as a director molecule, suppressing undesired reactions and thus increasing selectivity toward the desired reaction. These catalysts can be useful for a variety of chemical reactions including, in particular, the electrochemical conversion of CO.sub.2 or formic acid. The catalysts can also suppress H.sub.2 evolution, permitting electrochemical cell operation at potentials below RHE. Chemical processes and devices using the catalysts are also disclosed, including processes to produce CO, OH.sup.-, HCO.sup.-, H.sub.2CO, (HCO.sub.2).sup.-, H.sub.2CO.sub.2, CH.sub.3OH, CH.sub.4, C.sub.2H.sub.4, CH.sub.3CH.sub.2OH, CH.sub.3COO.sup.-, CH.sub.3COOH, C.sub.2H.sub.6, O.sub.2, H.sub.2, (COOH).sub.2, or (COO.sup.-).sub.2, and a specific device, namely, a CO.sub.2 sensor.

  19. Insights into the Mechanism of a Covalently-Linked Organic Dye-Cobaloxime Catalyst System for Dye Sensitized Solar Fuel Devices.

    PubMed

    Pati, Palas Baran; Zhang, Lei; Philippe, Bertrand; Fernández-Terán, Ricardo; Ahmadi, Sareh; Tian, Lei; Rensmo, Håkan; Hammarström, Leif; Tian, Haining

    2017-03-24

    A covalently-linked organic dye-cobaloxime catalyst system is developed by facile click reaction for mechanistic studies and application in dye sensitized solar fuel device based on mesoporous NiO. This system has been systematically investigated by photoelectrochemical measurements, density functional theory, time resolved fluorescence, transient absorption spectroscopy as well as photoelectron spectroscopy. The results show that irradiation of the dye-catalyst on NiO leads to ultrafast hole injection into NiO from the excited dye, followed by a fast electron transfer process to reduce the catalyst. Moreover, they suggest that the dye adopt different structures with different excited state energies, and excitation energy transfer occurs between neighboring molecules on the semiconductor surface. The photoelectrochemical experiments also show hydrogen production by this system. The axial chloride ligands of the catalyst are released during photocatalysis in order to create the active sites for proton reduction. A working mechanism of the dye-catalyst system on photocathode is eventually proposed on the basis of this study.

  20. Multifunctional catalysts based on carbon nanotubes and titanate nanotubes for oxidation of organic compounds in biphasic systems.

    PubMed

    Santos, S R A; Jardim, I S; Bicalho, H A; Binatti, I; Sousa, E M B; Peres, A M; Resende, R R; Lorençon, E

    2016-12-01

    Amphiphilic catalysts composed of carbon nanotubes (CNTs) and titanate nanotubes (TiNTs) have been successfully synthesized by refluxing anatase TiO2 and functionalised CNTs in concentrated NaOH solution. The prepared materials were characterized by transmission electron microscopy, scanning electron microscopy, X-ray diffraction, thermogravimetric analysis (TGA), and N2 physisorption isotherms. The catalytic activity of the synthesized composites was first evaluated in the oxidation of methyl yellow (MY) using H2O2 as oxidant in a single liquid phase system and in a biphasic water/oil mixture. The results of these experiments indicated that the catalytic activities of nanocomposites were very similar in the single liquid-phase oxidation. However, the modification of TiNTs with CNTs led to a substantially enhanced MY oxidation in the biphasic system. The nanocomposites show excellent interaction with both hydrophilic and hydrophobic compounds and thus stabilise emulsions. Under biphasic conditions, the catalysts can be easily separated and recycled, retaining catalytic activity even after eight runs. Additionally, the hybrid materials show superior catalytic activity and selectivity in the biphasic oxidation of benzyl alcohol with H2O2, as compared to pure TiNTs.

  1. Stabilized rhodium(0) nanoparticles: a reusable hydrogenation catalyst for arene derivatives in a biphasic water-liquid system.

    PubMed

    Schulz, J; Roucoux, A; Patin, H

    2000-02-18

    A colloidal system based on an aqueous suspension of rhodium(o) nanoparticles proved to be an efficient catalyst for the hydrogenation of arene derivatives under biphasic conditions. The rhodium nanoparticles (2-2.5 nm) were synthesized by the reduction of RhCl3 x 3H2O with sodium borohydride and were stabilized by highly water-soluble N-alkyl-N-(2-hydroxyethyl)ammonium salts (HEA-Cn). These surfactant molecules were characterized by measurements of the surface tension and the aqueous dispersions with rhodium were observed by transmission electron cryomicroscopy. The catalytic system is efficient under ultramild conditions, namely room temperature and 1 atm H2 pressure. The aqueous phase which contains the protected rhodium(0) colloids can be reused without significant loss of activity. The microheterogeneous behavior of this catalytic system was confirmed on a mercury poisoning experiment.

  2. Development of Optimal Catalyst Designs and Operating Strategies for Lean NOx Reduction in Coupled LNT-SCR Systems

    SciTech Connect

    Harold, Michael; Crocker, Mark; Balakotaiah, Vemuri; Luss, Dan; Choi, Jae-Soon; Dearth, Mark; McCabe, Bob; Theis, Joe

    2013-09-30

    Oxides of nitrogen in the form of nitric oxide (NO) and nitrogen dioxide (NO{sub 2}) commonly referred to as NO{sub x}, is one of the two chemical precursors that lead to ground-level ozone, a ubiquitous air pollutant in urban areas. A major source of NO{sub x} is generated by equipment and vehicles powered by diesel engines, which have a combustion exhaust that contains NO{sub x} in the presence of excess O{sub 2}. Catalytic abatement measures that are effective for gasoline-fueled engines such as the precious metal containing three-way catalytic converter (TWC) cannot be used to treat O2-laden exhaust containing NO{sub x}. Two catalytic technologies that have emerged as effective for NO{sub x} abatement are NO{sub x} storage and reduction (NSR) and selective catalytic reduction (SCR). NSR is similar to TWC but requires much larger quantities of expensive precious metals and sophisticated periodic switching operation, while SCR requires an on-board source of ammonia which serves as the chemical reductant of the NO{sub x}. The fact that NSR produces ammonia as a byproduct while SCR requires ammonia to work has led to interest in combining the two together to avoid the need for the cumbersome ammonia generation system. In this project a comprehensive study was carried out of the fundamental aspects and application feasibility of combined NSR/SCR. The project team, which included university, industry, and national lab researchers, investigated the kinetics and mechanistic features of the underlying chemistry in the lean NOx trap (LNT) wherein NSR was carried out, with particular focus on identifying the operating conditions such as temperature and catalytic properties which lead to the production of ammonia in the LNT. The performance features of SCR on both model and commercial catalysts focused on the synergy between the LNT and SCR converters in terms of utilizing the upstream-generated ammonia and alternative reductants such as propylene, representing the

  3. Exploring the cooperation effect of DBD byproducts and Ag/TiO2 catalyst for water treatment in an APPJ system

    NASA Astrophysics Data System (ADS)

    Guangliang, Chen; Wei, Hu; Jinsong, Yu; Wenxia, Chen; Jun, Huang

    2017-01-01

    In this paper, the collective effects of combining heterogeneous Ag/TiO2 nanocomposite catalyst with the byproducts (primarily the irradiation and the O3 species) of an atmospheric pressure plasma jet (APPJ) system on the degradation of methyl orange (MO) were explored. The heterostructured Ag/TiO2 nanocomposite was achieved via decorating the Ag quantum dots (QDs) on the commercially available TiO2 catalyst (P25) through a hydrothermal method. The x-ray diffraction analysis of the nanocomposite catalyst showed the diffraction peaks at 44.3°, 64.4°, and 77.5°, corresponding to the Ag planes of (200), (220) and (311), respectively. The high resolution transmission electron microscope characterization of the nanocomposite catalyst indicated that the Ag QDs with an average diameter of 5 nm were homogeneously distributed on the P25 surface. The experimental results on the MO photodegradation showed that the APPJ irradiation had a marginal effect on the cleavage of the MO molecules. When the Ag/TiO2 nanocomposite catalyst was used, the photodegradation rate of MO increased about 5 times. When both the APPJ byproducts and the Ag/TiO2 nanocomposite catalyst were used, however, over 90% of the MO in the tested solution was cleaved within 15 min, and the energy efficiency was about 0.6 g/kW h. Moreover, an optimal Ag dosage value was determined (6 wt%). The catalytic results indicated that combining the DBD plasma byproducts with heterogeneous nanocomposite catalysts may be an effect protocol for decreasing the application cost of the DBD system and mitigating the environment pollution by organic dyes in the textile industry.

  4. Highly dispersed metal catalyst

    DOEpatents

    Xiao, Xin; West, William L.; Rhodes, William D.

    2016-11-08

    A supported catalyst having an atomic level single atom structure is provided such that substantially all the catalyst is available for catalytic function. A process of forming a single atom catalyst unto a porous catalyst support is also provided.

  5. Mixed Alcohol Synthesis Catalyst Screening

    SciTech Connect

    Gerber, Mark A.; White, James F.; Stevens, Don J.

    2007-09-03

    National Renewable Energy Laboratory (NREL) and Pacific Northwest National Laboratory (PNNL) are conducting research to investigate the feasibility of producing mixed alcohols from biomass-derived synthesis gas (syngas). PNNL is tasked with obtaining commercially available or preparing promising mixed-alcohol catalysts and screening them in a laboratory-scale reactor system. Commercially available catalysts and the most promising experimental catalysts are provided to NREL for testing using a slipstream from a pilot-scale biomass gasifier. From the standpoint of producing C2+ alcohols as the major product, it appears that the rhodium catalyst is the best choice in terms of both selectivity and space-time yield (STY). However, unless the rhodium catalyst can be improved to provide minimally acceptable STYs for commercial operation, mixed alcohol synthesis will involve significant production of other liquid coproducts. The modified Fischer-Tropsch catalyst shows the most promise for providing both an acceptable selectivity to C2+ alcohols and total liquid STY. However, further optimization of the Fischer-Tropsch catalysts to improve selectivity to higher alcohols is highly desired. Selection of a preferred catalyst will likely entail a decision on the preferred coproduct slate. No other catalysts tested appear amenable to the significant improvements needed for acceptable STYs.

  6. Reforming catalyst

    SciTech Connect

    Baird, W.C. Jr.; Swan, G.A.

    1991-11-19

    This patent describes a catalyst useful for reforming a naphtha feed at high severity reforming conditions. It comprises the metals, platinum, rhenium and iridium on a refractory porous inorganic oxide support, the support consisting essentially of alumina, wherein the concentration by weight of each of the metals platinum and rhenium is at least 0.1 percent and iridium at least 0.15 percent and at least one of the metals is present in a concentration of at least 0.3 percent, and the sum-total; concentration of the metals is greater than 0.9 percent, and wherein each catalyst particle contains all three of the metals platinum, rhenium and iridium. This patent also describes this composition wherein the catalyst contains from about 0.1 percent to about 3 percent of a halogen and from about 0.05 percent to about 0.02 percent sulfur.

  7. Evaluation of the effects of a new combustion system and catalyst on engine emissions

    SciTech Connect

    Corbo, P.; Corcione, F.E.; Vaglieco, B.M.

    1990-01-01

    The paper reports the results of an experimental investigation carried out on a four-stroke single-cylinder D.I. diesel engine (100 {times} 95mm bore {times} stroke) with the aim to evaluate the effects of a four-lobe square combustion chamber on the gaseous and particulate emissions. Fluid-dynamic behaviour of the axisymmetric toroidal and four-lobe square chambers was investigated by Laser Doppler Anemometry. Engine tests at 2000 and 3000 rpm for different state of combustion (SOC) and A/F ratio are reported. Particulate, HC and NO{sub x} emission index measured under different operating conditions are given. In addition, the volatile content of the particulates produced from the two chambers at various engine operative conditions was measured by thermogravimetric analysis (TGA). Finally, the catalytic activity of a metal-oxide-based catalyst in the combustion of particulate was also evaluated by TGA.

  8. Brown algae hydrolysis in 1-n-butyl-3-methylimidazolium chloride with mineral acid catalyst system.

    PubMed

    Malihan, Lenny B; Nisola, Grace M; Chung, Wook-Jin

    2012-08-01

    The amenability of three brown algal species, Sargassum fulvellum, Laminaria japonica and Undaria pinnatifida, to hydrolysis were investigated using the ionic liquid (IL), 1-n-butyl-3-methylimidazolium chloride ([BMIM]Cl). Compositional analyses of the brown algae reveal that sufficient amounts of sugars (15.5-29.4 wt.%) can be recovered. Results from hydrolysis experiments show that careful selection of the type of mineral acid as catalyst and control of acid loading could maximize the recovery of sugars. Optimal reaction time and temperature were determined from the kinetic studies on the sequential reducing sugar (TRS) formation and degradation. Optimal reaction times were determined based on the extent of furfurals formation as TRS degradation products. X-ray diffraction and environmental scanning electron microscopy confirmed the suitability of [BMIM]Cl as solvent for the hydrolysis of the three brown algae. Overall results show the potential of brown algae as renewable energy resources for the production of valuable chemicals and biofuels.

  9. Responses of an immobilized-catalyst Belousov-Zabotinsky reaction system to electric fields

    NASA Astrophysics Data System (ADS)

    Miyakawa, Kenji; Mizoguchi, Michiko

    1998-11-01

    Effects of direct and alternating current electric fields on the chemical oscillator have been investigated. The chemical oscillator was realized by immersing the cation exchange bead loaded with the ferroin catalyst in the Belousov-Zabotinsky reaction solution. Various dynamic behaviors appeared depending on the direction, the frequency, and the strength of the electric field. Their time series were characterized in terms of power spectra. Observed behaviors were explained by assuming a field-induced transport of the inhibitor Br-. A phase diagram concerning dynamic behaviors was obtained as a function of the frequency and the strength of the electric field. The irregular oscillation was found to necessarily appear in the transition between 1/1 and 1/2 (or 2/1) entrainments. For further examination, a three-dimensional phase portrait was constructed using the time-delay method, and the largest Lyapunov exponent was calculated.

  10. Microstructure-strength relationships of heavily deformed Cu-based composites

    SciTech Connect

    Trybus, C.L.

    1988-01-01

    Heavily deformed Cu-based composites attain anomalous increases in strength upon mechanical deformation. The unique filamentary microstructures that evolve during processing (cold rolling, wire drawing or swaging) are the source of the strengthening. Composite strength is correlated to microstructural characteristics for arc-melted Cu-20 vol.% Nb cold rolled up to a true strain of 6.9. During rolling Nb elongates and becomes ribbon-like while the Cu matrix undergoes a cycle of deformation-dynamic recovery-recrystallization which allows for the further reduction of the Nb. Longitudinal and transverse specimens have equivalent mechanical properties. The ultimate tensile strength of the sheet showed a weak dependence on Nb filament spacing and its strength is controlled by a dislocation propagation mechanism. The feasibility of producing heavily deformed Cu-based composites via powder metallurgical processing techniques is explored because of the wider range of composite compositions which can be produced in contrast with ingot metallurgy.

  11. Nano-sized layered Mn oxides as promising and biomimetic water oxidizing catalysts for water splitting in artificial photosynthetic systems.

    PubMed

    Najafpour, Mohammad Mahdi; Heidari, Sima; Amini, Emad; Khatamian, Masoumeh; Carpentier, Robert; Allakhverdiev, Suleyman I

    2014-04-05

    One challenge in artificial photosynthetic systems is the development of artificial model compounds to oxidize water. The water-oxidizing complex of Photosystem II which is responsible for biological water oxidation contains a cluster of four Mn ions bridged by five oxygen atoms. Layered Mn oxides as efficient, stable, low cost, environmentally friendly and easy to use, synthesize, and manufacture compounds could be considered as functional and structural models for the site. Because of the related structure of these Mn oxides and the catalytic centre of the active site of the water oxidizing complex of Photosystem II, the study of layered Mn oxides may also help to understand more about the mechanism of water oxidation by the natural site. This review provides an overview of the current status of layered Mn oxides in artificial photosynthesis and discuss the sophisticated design strategies for Mn oxides as water oxidizing catalysts.

  12. Catalyst activator

    DOEpatents

    McAdon, Mark H.; Nickias, Peter N.; Marks, Tobin J.; Schwartz, David J.

    2001-01-01

    A catalyst activator particularly adapted for use in the activation of metal complexes of metals of Group 3-10 for polymerization of ethylenically unsaturated polymerizable monomers, especially olefins, comprising two Group 13 metal or metalloid atoms and a ligand structure including at least one bridging group connecting ligands on the two Group 13 metal or metalloid atoms.

  13. Hydrogen evolution reaction catalyst

    DOEpatents

    Subbaraman, Ram; Stamenkovic, Vojislav; Markovic, Nenad; Tripkovic, Dusan

    2016-02-09

    Systems and methods for a hydrogen evolution reaction catalyst are provided. Electrode material includes a plurality of clusters. The electrode exhibits bifunctionality with respect to the hydrogen evolution reaction. The electrode with clusters exhibits improved performance with respect to the intrinsic material of the electrode absent the clusters.

  14. Sabatier Catalyst Poisoning Investigation

    NASA Technical Reports Server (NTRS)

    Nallette, Tim; Perry, Jay; Abney, Morgan; Knox, Jim; Goldblatt, Loel

    2013-01-01

    The Carbon Dioxide Reduction Assembly (CRA) on the International Space Station (ISS) has been operational since 2010. The CRA uses a Sabatier reactor to produce water and methane by reaction of the metabolic CO2 scrubbed from the cabin air and the hydrogen byproduct from the water electrolysis system used for metabolic oxygen generation. Incorporating the CRA into the overall air revitalization system has facilitated life support system loop closure on the ISS reducing resupply logistics and thereby enhancing longer term missions. The CRA utilizes CO2 which has been adsorbed in a 5A molecular sieve within the Carbon Dioxide Removal Assembly, CDRA. There is a potential of compounds with molecular dimensions similar to, or less than CO2 to also be adsorbed. In this fashion trace contaminants may be concentrated within the CDRA and subsequently desorbed with the CO2 to the CRA. Currently, there is no provision to remove contaminants prior to entering the Sabatier catalyst bed. The risk associated with this is potential catalyst degradation due to trace organic contaminants in the CRA carbon dioxide feed acting as catalyst poisons. To better understand this risk, United Technologies Aerospace System (UTAS) has teamed with MSFC to investigate the impact of various trace contaminants on the CRA catalyst performance at relative ISS cabin air concentrations and at about 200/400 times of ISS concentrations, representative of the potential concentrating effect of the CDRA molecular sieve. This paper summarizes our initial assessment results.

  15. Corrosion behaviors of Al-Si-Cu-based filler metals and 6061-T6 brazements

    NASA Astrophysics Data System (ADS)

    Su, T. L.; Wang, S. S.; Tsao, L. C.; Chang, S. Y.; Chuang, T. H.; Yeh, M. S.

    2002-04-01

    The corrosion behaviors of a series of Al-Si-Cu-based filler metals and the 6061-T6 butt joints brazed with these filler metals are evaluated by polarization tests and immersion tests in a 3.5% NaCl aqueous solution. For comparison, a traditional Al-12Si filler metal is also employed. The results indicate that the Al-Si-Cu-based filler metals before brazing possess much higher corrosion current densities and pitting tendencies than the Al-12Si filler metal. However, brazing of the 6061-T6 alloy with an Al-12Si filler metal produces a wider butt joint, which, in this case, creates a more extensive corrosion region. Severe galvanic corrosion occurs at the 6061-T6 joints when brazed with Al-Si-Cu-based filler metals. However, in the case of the 6061-T6/Al-12Si brazements, selective corrosion of the Al-12Si eutectic phase can be observed. The bonding strengths of the 6061-T6 butt joints brazed with various filler metals are also measured before and after the immersion tests.

  16. Method and system for the combination of non-thermal plasma and metal/metal oxide doped .gamma.-alumina catalysts for diesel engine exhaust aftertreatment system

    DOEpatents

    Aardahl, Christopher L.; Balmer-Miller, Mari Lou; Chanda, Ashok; Habeger, Craig F.; Koshkarian, Kent A.; Park, Paul W.

    2006-07-25

    The present disclosure pertains to a system and method for treatment of oxygen rich exhaust and more specifically to a method and system that combines non-thermal plasma with a metal doped .gamma.-alumina catalyst. Current catalyst systems for the treatment of oxygen rich exhaust are capable of achieving only approximately 7 to 12% NO.sub.x reduction as a passive system and only 25 40% reduction when a supplemental hydrocarbon reductant is injected into the exhaust stream. It has been found that treatment of an oxygen rich exhaust initially with a non-thermal plasma and followed by subsequent treatment with a metal doped .gamma.-alumina prepared by the sol gel method is capable of increasing the NO.sub.x reduction to a level of approximately 90% in the absence of SO.sub.2 and 80% in the presence of 20 ppm of SO.sub.2. Especially useful metals have been found to be indium, gallium, and tin.

  17. A semiconductor gas sensor system for high throughput screening of heterogeneous catalysts for the production of benzene derivatives

    NASA Astrophysics Data System (ADS)

    Yamada, Yusuke; Ueda, Atsushi; Shioyama, Hiroshi; Maekawa, Toru; Kanda, Keisen; Suzuki, Kengo; Kobayashi, Tetsuhiko

    2005-01-01

    We used a semiconductor gas sensor system developed for odour discrimination for a rapid quantification of benzene derivatives which can be formed as the product of a catalytic reaction. Phenol can be obtained by the selective oxidation of benzene. The sensor system shows higher sensitivity to phenol than benzene. In particular, a SnO2 sensor sensitized with ZrO2 responds selectively to phenol. Aniline is provided as a reaction product between ammonia and benzene. The output signal of the gas sensor system increases when it is exposed to air containing aniline at the ppm level; on the other hand, the sensor output resulting from 1% ammonia in air does not increase so much. Cumene formation can be observed by the reaction of propane and benzene. The sensitivity of a SnO2 sensor sensitized with 12%SiO2-Al2O3 to cumene was about ten times higher than that to benzene. These results indicate that the semiconductor gas sensor system is useful for rapid screening of the catalyst for benzene functionalization.

  18. Manganese oxide supported on gold/iron as a water-oxidizing catalyst in artificial photosynthetic systems.

    PubMed

    Najafpour, Mohammad Mahdi; Hosseini, Seyedeh Maedeh; Zand, Zahra

    2016-05-31

    Herein, we reported that KMnO4 with iron nanoparticles coated with gold layers was a promising catalyst for water oxidation. The compound was characterized by scanning electron microscopy, energy-dispersive spectroscopy, transmission electron microscopy, X-ray diffraction, Raman spectroscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, atomic absorption spectroscopy and electrochemistry. The new compound was a conductive, recyclable, highly dispersible, magnetically separable, environmentally friendly, and nano-sized catalyst for water oxidation via cerium(iv) ammonium nitrate or Ru(bpy)3(3+) and electrochemical water oxidation. The turnover frequency of Mn oxide/gold/iron for water oxidation via cerium(iv) ammonium nitrate is 0.4 mmol O2 per mol Mn per second, which shows that this catalyst is among the best Mn-based catalysts for water oxidation. We also showed a strategy for placing this catalyst on the surface of an electrode without adding any other compounds.

  19. Catalyst suppliers consolidate further, offer more catalysts

    SciTech Connect

    Rhodes, A.K.

    1995-10-02

    The list of suppliers of catalysts to the petroleum refining industry has decreased by five since Oil and Gas Journal`s survey of refining catalysts and catalytic additives was last published. Despite the consolidation, the list of catalyst designations has grown to about 950 in this latest survey, compared to 820 listed in 1993. The table divides the catalysts by use and gives data on their primary differentiating characteristics, feedstock, products, form, bulk density,catalyst support, active agents, availability, and manufactures.

  20. Synthesis and characterization of novel antibacterial polymers and clay delivery systems and polymeric phase transfer catalysts

    NASA Astrophysics Data System (ADS)

    Dizman, Bekir

    The research presented in this dissertation involves the syntheses of both novel antibacterial polymers and nanocomposites and polymeric phase transfer catalysts. The first section describes the synthesis, characterization, and antibacterial activities of new acrylate/methacrylate and acrylamide/methacrylamide polymers containing pendant quaternary ammonium compounds and norfloxacin. The first part of this section focuses on the syntheses and antibacterial activities of new water-soluble bis-quaternary ammonium methacrylate monomers and polymers (Chapter II). The monomers and polymers showed antibacterial activities against Staphylococcus aureus and Escherichia coli and the activity increased as the alkyl chain length in ammonium groups increased from 4 to 6 carbons. The results are very encouraging since polymers with quaternary ammonium compounds containing short alkyl chains are generally not active against bacteria. The second part of the first section involves the syntheses and antibacterial activities of various new monomers and polymers with amine and mono-quaternary ammonium groups on the side chain (Chapter III). The monomers were either the derivatives of 3-(acryloyloxy)-2-hydroxypropyl methacrylate (AHM) or based on acrylamide and methacrylamide derivatives. All monomers were homopolymerized and copolymerized with 2-hydroxyethylmethacrylate (HEMA). Amine monomers, their homopolymers and copolymers did not show any antibacterial activity against S. aureus and E. coli while the quaternized AHM-3-(aminomethyl) pyridine monomer, its homopolymer and copolymer with HEMA showed antibacterial activities against both bacteria. It was also found that the antibacterial activity of the quaternized methacrylamide-3-(aminomethyl) pyridine monomers and polymers increased as the alkyl chain length in ammonium groups increased. (Abstract shortened by UMI.)

  1. Hydrocracking catalyst

    SciTech Connect

    Arias, B.; Galiasso, R.; Kum, H.

    1985-02-12

    The invention relates to a particular method for the preparation of a hydrocracking catalyst, using a high iron content bauxite as a basis. This bauxite is ground and screened to a specific size and mixed with three types of additives: a promoter additive of the P, Mo, Co, Ni, W type. A hardener additive of the phosphoric acid type, ammonium phosphate. And a lubricant and pore-generating additive of the polyvinyl alcohol, polyethylene-glycol, starch type. The particularity consists in that the three additives are added simultaneously during the extrusion of the sample. That way, a particular surface composition is obtained which allows for the activity of the catalyst. Extruded products are obtained in sizes of 1/8, 1/16, and 1/32'' and submitted to drying and calcination programs for their activation. The obtained catalyst offers a good mechanical strength, a high content in macropores and a high activity, specifically for the hydrocracking of heavy Venezuelan crudes or residues.

  2. A Two-Component Alkyne Metathesis Catalyst System with an Improved Substrate Scope and Functional Group Tolerance: Development and Applications to Natural Product Synthesis.

    PubMed

    Schaubach, Sebastian; Gebauer, Konrad; Ungeheuer, Felix; Hoffmeister, Laura; Ilg, Marina K; Wirtz, Conny; Fürstner, Alois

    2016-06-13

    Although molybdenum alkylidyne complexes such as 1 endowed with triarylsilanolate ligands are excellent catalysts for alkyne metathesis, they can encounter limitations when (multiple) protic sites are present in a given substrate and/or when forcing conditions are necessary. In such cases, a catalyst formed in situ upon mixing of the trisamidomolybenum alkylidyne complex 3 and the readily available trisilanol derivatives 8 or 11 shows significantly better performance. This two-component system worked well for a series of model compounds comprising primary, secondary or phenolic -OH groups, as well as for a set of challenging (bis)propargylic substrates. Its remarkable efficiency is also evident from applications to the total syntheses of manshurolide, a highly strained sesquiterpene lactone with kinase inhibitory activity, and the structurally demanding immunosuppressive cyclodiyne ivorenolide A; in either case, the standard catalyst 1 largely failed to effect the critical macrocyclization, whereas the two-component system was fully operative. A study directed toward the quinolizidine alkaloid lythrancepine I features yet another instructive example, in that a triyne substrate was metathesized with the help of 3/11 such that two of the triple bonds participated in ring closure, while the third one passed uncompromised. As a spin-off of this project, a much improved ruthenium catalyst for the redox isomerization of propargyl alcohols to the corresponding enones was developed.

  3. Introducing a closed system approach for the investigation of chemical steps involving proton and electron transfer; as illustrated by a copper-based water oxidation catalyst.

    PubMed

    de Ruiter, Jessica M; Buda, Francesco

    2017-02-08

    The investigation of the catalytic mechanism of homogeneous water oxidation catalysts remains an active field of research. When examining catalytic steps theoretically, it is often difficult to account for the transfer of protons and electrons from step to step. To this end, a closed system approach is proposed which includes both proton and electron acceptors in the simulation box to allow for the description of proton-coupled electron transfer processes. Using Car-Parrinello Molecular Dynamics, a mononuclear copper water oxidation catalyst Cu(bpy)(OH)2 was used as a model system to explore this closed system approach. The exploration of this model system shows that, compared to traditional methods, this approach offers extra insight into proposed catalytic steps and allows for the clear identification of preferred reaction paths.

  4. Development of brazing process for W-EUROFER joints using Cu-based fillers

    NASA Astrophysics Data System (ADS)

    de Prado, J.; Sánchez, M.; Ureña, A.

    2016-02-01

    A successful joint between W and EUROFER using high temperature brazing technique has been achieved for structural application in future fusion power plants. Cu-based powder alloy mixed with a polymeric binder has been used as filler. Microstructural analysis of the joints revealed that the joint consisted mainly of primary phases and acicular structures in a Cu matrix. Interaction between EUROFER and filler took place at the interface giving rise to several Cu-Ti-Fe rich layers. A loss of hardness at the EUROFER substrate close to the joint due to a diffusion phenomenon during brazing cycle was measured; however, the joints had an adequate shear strength value.

  5. Electronic modification of Cu-based chalcopyrite semiconductors induced by lattice deformation and composition alchemy

    NASA Astrophysics Data System (ADS)

    Jiang, F. D.; Feng, J. Y.

    2008-02-01

    Using first principles calculation, we systematically investigate the electronic modification of Cu-based chalcopyrite semiconductors induced by lattice deformation and composition alchemy. It is shown that the optical band gap Eg is remarkably sensitive to the anion displacement μ, resulting from the opposite shifts of conduction band minimum and valence band maximum. Meanwhile, the dependence of structural parameters of alloyed compounds on alloy composition x is demonstrated for both cation and anion alloying. The d orbitals of group-III cations are found to be of great importance in the calculation. Abnormal changes in the optical band gap Eg induced by anion alloying are addressed.

  6. In-line localized monitoring of catalyst activity in selective catalytic NO.sub.x reduction systems

    DOEpatents

    Muzio, Lawrence J.; Smith, Randall A.

    2009-12-22

    Localized catalyst activity in an SCR unit for controlling emissions from a boiler, power plant, or any facility that generates NO.sub.x-containing flue gases is monitored by one or more modules that operate on-line without disrupting the normal operation of the facility. Each module is positioned over a designated lateral area of one of the catalyst beds in the SCR unit, and supplies ammonia, urea, or other suitable reductant to the catalyst in the designated area at a rate that produces an excess of the reductant over NO.sub.x on a molar basis through the designated area. Sampling probes upstream and downstream of the designated area draw samples of the gas stream for NO.sub.x analysis, and the catalyst activity is determined from the difference in NO.sub.x levels between the two probes.

  7. Enhanced catalyst for conversion of syngas to liquid motor fuels

    DOEpatents

    Coughlin, Peter K.; Rabo, Jule A.

    1985-01-01

    Synthesis gas comprising carbon monoxide and hydrogen is converted to C.sub.5.sup.+ hydrocarbons suitable for use as liquid motor fuels by contact with a dual catalyst system capable of enhancing the selectivity of said conversion to motor fuel range hydrocarbons and the quality of the resulting motor fuel product. The catalyst composition employs a Fischer-Tropsch catalyst, together with a co-catalyst/support component comprising SAPO silicoaluminophosphate, non-zeolitic molecular sieve catalyst.

  8. Enhanced catalyst for conversion of syngas to liquid motor fuels

    DOEpatents

    Coughlin, P.K.; Rabo, J.A.

    1985-12-03

    Synthesis gas comprising carbon monoxide and hydrogen is converted to C[sub 5][sup +] hydrocarbons suitable for use as liquid motor fuels by contact with a dual catalyst system capable of enhancing the selectivity of said conversion to motor fuel range hydrocarbons and the quality of the resulting motor fuel product. The catalyst composition employs a Fischer-Tropsch catalyst, together with a co-catalyst/support component comprising a SAPO silicoaluminophosphate, non-zeolitic molecular sieve catalyst.

  9. Autothermal reforming catalyst having perovskite structure

    DOEpatents

    Krumpel, Michael; Liu, Di-Jia

    2009-03-24

    The invention addressed two critical issues in fuel processing for fuel cell application, i.e. catalyst cost and operating stability. The existing state-of-the-art fuel reforming catalyst uses Rh and platinum supported over refractory oxide which add significant cost to the fuel cell system. Supported metals agglomerate under elevated temperature during reforming and decrease the catalyst activity. The catalyst is a perovskite oxide or a Ruddlesden-Popper type oxide containing rare-earth elements, catalytically active firs row transition metal elements, and stabilizing elements, such that the catalyst is a single phase in high temperature oxidizing conditions and maintains a primarily perovskite or Ruddlesden-Popper structure under high temperature reducing conditions. The catalyst can also contain alkaline earth dopants, which enhance the catalytic activity of the catalyst, but do not compromise the stability of the perovskite structure.

  10. Cationic ruthenium alkylidene catalysts bearing phosphine ligands.

    PubMed

    Endo, Koji; Grubbs, Robert H

    2016-02-28

    The discovery of highly active catalysts and the success of ionic liquid immobilized systems have accelerated attention to a new class of cationic metathesis catalysts. We herein report the facile syntheses of cationic ruthenium catalysts bearing bulky phosphine ligands. Simple ligand exchange using silver(i) salts of non-coordinating or weakly coordinating anions provided either PPh3 or chelating Ph2P(CH2)nPPh2 (n = 2 or 3) ligated cationic catalysts. The structures of these newly reported catalysts feature unique geometries caused by ligation of the bulky phosphine ligands. Their activities and selectivities in standard metathesis reactions were also investigated. These cationic ruthenium alkylidene catalysts reported here showed moderate activity and very similar stereoselectivity when compared to the second generation ruthenium dichloride catalyst in ring-closing metathesis, cross metathesis, and ring-opening metathesis polymerization assays.

  11. Case in Point: A Special Education Lawsuit: Catalyst for Positive Systemic Change? Maybe. Maybe Not.

    ERIC Educational Resources Information Center

    Amos, Gayle V.

    2003-01-01

    A special education lawsuit against the Baltimore City Public School System resulted in a consent decree that evolved into a systemwide management plan. By 1997, the system collapsed and a city-state partnership integrated special and regular education. The focus on outcomes for court disengagement instead of student outcomes is discussed. (CR)

  12. Development of a condenser for the dual catalyst water recovery system

    NASA Technical Reports Server (NTRS)

    Budinikas, P.; Rasouli, F.; Rabadi, N.

    1983-01-01

    Conceptual evaporation/condensation systems suitable for integration with the catalytic water recovery method were evaluated. The primary requirements for each concept were its capability to operate under zero-gravity conditions, condense recovered water from a vapor-noncondensable gas mixture, and integrate with the catalytic system. Specific energy requirements were estimated for concepts meeting the primary requirements, and the concept most suitable for integration with the catalytic system was proposed. A three-man rate condenser capable of integration with the proposed system, condensing water vapor in presence of noncondensables and transferring the heat of condensation to feed urine was designed, fabricated, and tested. It was treated with steam/air mixtures at atmospheric and elevated pressures and integrated with an actual catalytic water recovery system. The condenser has a condensation efficiency exceeding 90% and heat transfer rate of approximately 85% of theoretical value at coolant temperature ranging from 7 to 80 deg C.

  13. Cracking catalyst

    SciTech Connect

    Otterstedt, J. E. A.; Jaras, S. G.; Pudas, R.; Upson, L. L.

    1985-05-07

    A cracking catalyst having good resistance to metal poisoning has at least two particle fractions of different particle sizes, the cracking catalyzing zeolite material being concentrated to the coarser particle size fractions, and the finer particle size fractions being formed from material having relatively lower or no or insignificant cracking catalyzing activity. The particles of the finer particle size fractions have a matrix of kaolin and amorphous alumina--silica and may contain for example, an SO /SUB x/ eliminating additive such as Al/sub 2/O/sub 3/, CaO and/or MgO. The coarser particle size fractions having cracking catalyzing effect have a mean particle size of from 80 to 125 ..mu..m and the finer particle size fractions a mean particle size of from 30 to 75 ..mu..m. The coarser particle size fractions have a zeolite content of at least 20 weight % and may have a zeolite content of up to 100 weight %, the remainder consisting essentially of material which has relatively lower or no or insignificant cracking-catalyzing activity and which consists of kaolin and amorphous alumina-silica. The catalyst mass as a whole may have a zeolite content of up to 50 weight %.

  14. Theoretical investigation on thermoelectric properties of Cu-based chalcopyrite compounds

    NASA Astrophysics Data System (ADS)

    Wang, Biao; Xiang, Hongjun; Nakayama, Tsuneyoshi; Zhou, Jun; Li, Baowen

    2017-01-01

    Cu-based materials are potential candidates for commercial thermoelectric materials due to their abundance, nontoxicity, and high performance. We incorporate the multiband Boltzmann transport equations with first-principles calculations to theoretically investigate the thermoelectric properties of Cu-based chalcopyrite compounds. As a demonstration of our method, the thermoelectric properties of quaternary compounds Cu2ZnSnX4 (X = S, Se) and ternary compounds CuBTe2 (B = Ga, In) are studied. We systematically calculate the electrical conductivity, the Seebeck coefficient, and the power factor of the four materials above based on parameters obtained from first-principles calculations and using several other fitting parameters. For quaternary compounds, our results reveal that Cu2ZnSnSe4 is better than Cu2ZnSnS4 and its optimal hole concentration is around 5 ×1019cm-3 with the peak power factor 4.7 μ W/cm K 2 at 600 K. For ternary compounds, we find that their optimal hole concentrations are around 1 ×1020cm-3 with the peak power factors over 26 μ W/cm K 2 at 800 K.

  15. Four-man rated dual catalyst system for the recovery of water from urine

    NASA Technical Reports Server (NTRS)

    Budininkas, P.

    1978-01-01

    The catalytic system was integrated with a 4-man rated urine wick evaporator. During operation, urine vapor produced by the wick-evaporator was treated in the catalytic system to remove ammonia and volatile hydrocarbons, and water was recovered by condensation in a water cooled condenser. The system operated completely automatically and required no manual adjustments, except periodic supply of urine and removal of the recovered water. Although the system was designed for treating 0.325 kg urine per hour, this rate could be achieved only with a fresh wick, then gradually decreased as the wick became saturated with urine solids. The average urine treatment rates achieved during each of the three endurance tests were 0.137, 0.217, and 0.235 kg/hr. The quality of the recovered water meets drinking water standards, with the exception of a generally low pH.

  16. Surface analysis of model systems: From a metal-graphite interface to an intermetallic catalyst

    SciTech Connect

    Kwolek, Emma J.

    2016-10-25

    This thesis summarizes research completed on two different model systems. In the first system, we investigate the deposition of the elemental metal dysprosium on highly-oriented pyrolytic graphite (HOPG) and its resulting nucleation and growth. The goal of this research is to better understand the metal-carbon interactions that occur on HOPG and to apply those to an array of other carbon surfaces. This insight may prove beneficial to developing and using new materials for electronic applications, magnetic applications and catalysis.

  17. Diagnostics for emission-control-system malfunction on three-way catalyst-equipped vehicles. Final report, November 1983-November 1985

    SciTech Connect

    Duleep, K.G.

    1985-11-01

    The report presents the results of a two part study. In Phase I, the contractor reviewed current manufacturer recommended diagnostic procedures for identifying vehicular emission control malfunctions on three-way catalyst-equipped gasoline-fueled automobiles and also surveyed diagnostic techniques used in the field. Diagnosis of malperformance was limited to the following systems: exhaust gas recirculating, secondary air, fuel, and catalyst. In Phase II, the contractor developed generalized diagnostic procedures for malfunctioning emission control systems and validated these procedures on 52 vehicles. Two mechanics alternatively disabled and repaired the vehicles using the diagnostic and repair procedures. The report also describes inspection procedures developed for the control of smoke emissions from light-duty diesel vehicles. Two types of procedures were developed, for component testing and for inspection/maintenance programs. These procedures were validated on six light-duty vehicles.

  18. Modeling of the chemical-looping combustion of methane using a Cu-based oxygen-carrier

    SciTech Connect

    Abad, Alberto; Adanez, Juan; Garcia-Labiano, Francisco; de Diego, Luis F.; Gayan, Pilar

    2010-03-15

    A mathematical model for a bubbling fluidized bed has been developed to simulate the performance of the fuel-reactor in chemical-looping combustion (CLC) systems. This model considers both the fluid dynamic of the fluidized bed and freeboard and the kinetics of reduction of the oxygen-carrier, here CuO impregnated on alumina. The main outputs of the model are the conversion of the carrier and the gas composition at the reactor exit, the axial profiles of gas concentrations and the fluid dynamical structure of the reactor. The model was validated using measurements when burning CH{sub 4} in a 10 kW{sub th} prototype using a Cu-based oxygen-carrier. The influence of the circulation rate of solids, the load of fuel gas, the reactor temperature and size of the oxygen-carrier particles were analyzed. Combustion efficiencies predicted by the model showed a good agreement with measurements. Having validated the model, the implications for designing and optimizing a fuel-reactor were as follows. The inventory of solids for a high conversion of the fuel was sensitive to the reactor's temperature, the solids' circulation rate and the extent to which the solids entering to the reactor had been regenerated. The optimal ratio of oxygen-carrier to fuel was found to be 1.7-4 for the Cu-based oxygen-carrier used here. In this range, the inventory of solids to obtain a combustion efficiency of 99.9% at 1073 K was less than 130 kg/MW{sub th}. In addition, the model's results were very sensitive to the resistance to gas diffusing between the emulsion and bubble phases in the bed, to the decay of solids' concentration in the freeboard and to the efficiency contact between gas and solids in the freeboard. Thus, a simplified model, ignoring any restriction to gas and solids contacting each other, will under-predict the inventory of solids by a factor of 2-10. (author)

  19. Near-edge band structures and band gaps of Cu-based semiconductors predicted by the modified Becke-Johnson potential plus an on-site Coulomb U

    SciTech Connect

    Zhang, Yubo; Zhang, Jiawei; Wang, Youwei; Gao, Weiwei; Abtew, Tesfaye A.; Zhang, Peihong E-mail: wqzhang@mail.sic.ac.cn; Zhang, Wenqing E-mail: wqzhang@mail.sic.ac.cn

    2013-11-14

    Diamond-like Cu-based multinary semiconductors are a rich family of materials that hold promise in a wide range of applications. Unfortunately, accurate theoretical understanding of the electronic properties of these materials is hindered by the involvement of Cu d electrons. Density functional theory (DFT) based calculations using the local density approximation or generalized gradient approximation often give qualitative wrong electronic properties of these materials, especially for narrow-gap systems. The modified Becke-Johnson (mBJ) method has been shown to be a promising alternative to more elaborate theory such as the GW approximation for fast materials screening and predictions. However, straightforward applications of the mBJ method to these materials still encounter significant difficulties because of the insufficient treatment of the localized d electrons. We show that combining the promise of mBJ potential and the spirit of the well-established DFT + U method leads to a much improved description of the electronic structures, including the most challenging narrow-gap systems. A survey of the band gaps of about 20 Cu-based semiconductors calculated using the mBJ + U method shows that the results agree with reliable values to within ±0.2 eV.

  20. Integrated System in the Malaysian Education Paradigm: A Catalyst for a Holistic Personality Development

    ERIC Educational Resources Information Center

    Othman, Nooraini; Mohamad, Khairul Azmi

    2014-01-01

    This paper intends to describe and analyse the process of education reform that has taken place in Malaysia. Islamisation plays a major role in such reform. The approach is innovative and novel in nature. Historically, Malaysia was under the British colony and the British left a strong impact in the education system. Naturally the position of…

  1. Facile heterogenization of a cobalt catalyst via graphene adsorption: robust and versatile dihydrogen production systems.

    PubMed

    Eady, Shawn C; Peczonczyk, Sabrina L; Maldonado, Stephen; Lehnert, Nicolai

    2014-07-28

    A heterogeneous dihydrogen (H2) production system has been attained by simply soaking electrodes made from electro-deposited graphene on FTO plated glass in solutions of a cobalt bis(dithiolate) compound. The resulting electrodes are active in weakly acidic aqueous solutions (pH > 3), have relatively low overpotentials (0.37 V versus platinum), show high catalytic rates (TOF > 1000 s(-1)), and are resistant to degradation by dioxygen.

  2. Structure and characteristics of chitosan cobalt-containing hybrid systems, the catalysts of olefine oxidation

    NASA Astrophysics Data System (ADS)

    Mekhaev, A. V.; Pestov, A. V.; Molochnikov, L. S.; Kovaleva, E. G.; Pervova, M. G.; Yaltuk, Yu. G.; Grigor'ev, I. A.; Kirilyuk, I. A.

    2011-07-01

    Cobalt-containing hybrid organo-inorganic materials based on the chitosan-SiO2, chitosan-Al2O3, and chitosan-cellulose systems were obtained. The surface structure and processes that occur during the formation of metal-containing materials, the catalytic properties of which were studied in the oxidation reactions of alkene, were investigated by EPR spectroscopy using a stable pH-sensitive nitroxyl radical, 4-dimethylamino-2-ethyl-5,5-dimethyl-2-(pyridin-4-yl)-2,5-dihydro-1H-imidazole-1-oxyl, as the adsorbed probe molecules.

  3. Method of treating emissions of a hybrid vehicle with a hydrocarbon absorber and a catalyst bypass system

    SciTech Connect

    Roos, Bryan Nathaniel; Gonze, Eugene V; Santoso, Halim G; Spohn, Brian L

    2014-01-14

    A method of treating emissions from an internal combustion engine of a hybrid vehicle includes directing a flow of air created by the internal combustion engine when the internal combustion engine is spinning but not being fueled through a hydrocarbon absorber to collect hydrocarbons within the flow of air. When the hydrocarbon absorber is full and unable to collect additional hydrocarbons, the flow of air is directed through an electrically heated catalyst to treat the flow of air and remove the hydrocarbons. When the hydrocarbon absorber is not full and able to collect additional hydrocarbons, the flow of air is directed through a bypass path that bypasses the electrically heated catalyst to conserve the thermal energy stored within the electrically heated catalyst.

  4. Design, fabrication and testing of a dual catalyst ammonia removal system for a urine VCD unit

    NASA Technical Reports Server (NTRS)

    Budinikas, P.

    1980-01-01

    A three-man capacity catalytic system for the recovery of water from urine was designed, constructed, and tested, it was designed to operate with feed streams containing high concentrations of urine vapor and only 5 to 7% of oxygen for the oxidation of ammonia and volatile organic vapor.It can operate either in a flow-through or a recycle mode and is capable of accepting the urine vapor produced by a vapor compression distillation evaporator. Testing consisted of short preliminary and optimization test, an endurance test of 74 hours continuous operation, and recycle tests using both air and oxygen. The system was designed for a urine processing rate of 0.86 liters/hr; however, it was tested at rates up to 1.2 liter/hr. Untreated urine evaporated by an electrically heated evaporator was used. The quality of the recovered water meets the U.S. Drinking Water Standards, with the exception of a low pH. Accumulation of solids in the urine sludge is reduced to approximately 65% of the anticipated value.

  5. Wet air oxidation of pretreatment of pharmaceutical wastewater by Cu2+ and [PxWmOy]q- co-catalyst system.

    PubMed

    Wang, Guowen; Wang, Dong; Xu, Xiaochen; Liu, Lifen; Yang, Fenglin

    2012-05-30

    This study concentrates on the pretreatment of real wastewater using catalytic wet air oxidation (CWAO). WO(3-) and PO(4)(3-) contained in fosfomycin pharmaceutical wastewater (FPW) and Cu(2+) contained in berberine pharmaceutical wastewater (BPW) were studied as CWAO influent. Mixture of this two streams were reused to form Cu(2+) and [P(x)W(m)O(y)](q-), namely polyoxometalates (POMs) as co-catalyst system to treat themselves. Experiments were conducted to investigate the effects of the initial oxygen pressure and temperature on the COD (chemical oxygen demand), TOC (total organic carbon) removal and biodegradable enhancement, it was discovered that over 40% of COD and TOC removal can be easily realized in an hour of WAO oxidation at 523 K, 1.4 MPa. The BOD(5)/COD (BOD(5), biochemical oxygen demand in 5 days) of this two pharmaceutical mixture ascended from nonexistent to maximum 0.41 depends on the optimal FPW:BPW volume ratio 4:1, to compose POM co-catalyst system. Organic pollutants were incompletely oxidized to propionic acid and other intermediates. Some properties (e.g., TGA, IR, XRF) of POM catalyst separated from effluent, were obtained to provide additional information.

  6. Characterisation of a PdCl 2/SnCl 2 electroless plating catalyst system adsorbed on barium titanate-based electroactive ceramics

    NASA Astrophysics Data System (ADS)

    Meenan, B. J.; Brown, N. M. D.; Wilson, J. W.

    1994-03-01

    A PdCl 2/SnCl 2 metallisation catalyst system, of the type used to activate non-conducting surfaces for electroless metal deposition, has been characterised by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The substrate is a barium titanate (BaTiO 3)-based electroactive ceramic of the type used in the fabrication of multilayer ceramic capacitors (MLCC). The treatment of the substrate surface with the PdCl 2/SnCl 2 "sensitiser" solution leads to the adsorption of catalytically inactive compounds of palladium and tin. Subsequent treatment of this surface with an "accelerator" solution removes excess oxides, hydroxides and salts of tin thereby leaving the active catalyst species, Pd xSn y, on the surface. Such sites, on exposure to the appropriete electroless plating bath, are then responsible for the metal deposition. In this study, the chemical state and relative quantities of the various surface species present after each of the processing stages have been determined by XPS. The surface roughness of the substrate results in less of the tin compounds present thereon being removed on washing the catalysed surface in the accelerator solution than normally reported for such systems, thereby affecting the measured Pd: Sn ratio. SEM studies show that the accelerator solution treatment generates crystalline areas, which may be a result of coagulation of the Pd xSn y particles present, in the otherwise amorphous catalyst coating.

  7. Ceria nanoclusters on graphene/Ru(0001): A new model catalyst system

    SciTech Connect

    Novotny, Z.; Netzer, F. P.; Dohnalek, Z.

    2016-03-22

    In this study, the growth of ceria nanoclusters on single-layer graphene on Ru(0001) has been examined, with a view towards fabricating a stable system for model catalysis studies. The surface morphology and cluster distribution as a function of oxide coverage and substrate temperature has been monitored by scanning tunneling microscopy (STM), whereas the chemical composition of the cluster deposits has been determined by Auger electron spectroscopy (AES). The ceria nanoparticles are of the CeO2(111)-type and are anchored at the intrinsic defects of the graphene surface, resulting in a variation of the cluster densities across the macroscopic sample surface. The ceria clusters on graphene display a remarkable stability against reduction in ultrahigh vacuum up to 900 K, but some sintering of clusters is observed for temperatures > 450 K. The evolution of the cluster size distribution suggests that the sintering proceeds via a Smoluchowski ripening mechanism, i.e. diffusion and aggregation of entire clusters.

  8. Systems including catalysts in porous zeolite materials within a reactor for use in synthesizing hydrocarbons

    DOEpatents

    Rolllins, Harry W [Idaho Falls, ID; Petkovic, Lucia M [Idaho Falls, ID; Ginosar, Daniel M [Idaho Falls, ID

    2012-07-24

    Catalytic structures include a catalytic material disposed within a zeolite material. The catalytic material may be capable of catalyzing a formation of methanol from carbon monoxide and/or carbon dioxide, and the zeolite material may be capable of catalyzing a formation of hydrocarbon molecules from methanol. The catalytic material may include copper and zinc oxide. The zeolite material may include a first plurality of pores substantially defined by a crystal structure of the zeolite material and a second plurality of pores dispersed throughout the zeolite material. Systems for synthesizing hydrocarbon molecules also include catalytic structures. Methods for synthesizing hydrocarbon molecules include contacting hydrogen and at least one of carbon monoxide and carbon dioxide with such catalytic structures. Catalytic structures are fabricated by forming a zeolite material at least partially around a template structure, removing the template structure, and introducing a catalytic material into the zeolite material.

  9. Ceria nanoclusters on graphene/Ru(0001): A new model catalyst system

    NASA Astrophysics Data System (ADS)

    Novotny, Z.; Netzer, F. P.; Dohnálek, Z.

    2016-10-01

    The growth of ceria nanoclusters on single-layer graphene on Ru(0001) has been examined, with a view towards fabricating a stable system for model catalysis studies. The surface morphology and cluster distribution as a function of oxide coverage and substrate temperature has been monitored by scanning tunneling microscopy (STM), whereas the chemical composition of the cluster deposits has been determined by Auger electron spectroscopy (AES). The ceria nanoparticles are of the CeO2(111)-type and are anchored at the intrinsic defects of the graphene surface, resulting in a variation of the cluster densities across the macroscopic sample surface. The ceria clusters on graphene display a remarkable stability against reduction in ultrahigh vacuum up to 900 K, but some sintering of clusters is observed for temperatures > 450 K. The evolution of the cluster size distribution suggests that the sintering proceeds via a Smoluchowski ripening mechanism, i.e. diffusion and aggregation of entire clusters.

  10. Rapid Syphilis Tests as Catalysts for Health Systems Strengthening: A Case Study from Peru

    PubMed Central

    García, Patricia J.; Cárcamo, César P.; Chiappe, Marina; Valderrama, Maria; La Rosa, Sayda; Holmes, King K.; Mabey, David C. W.; Peeling, Rosanna W.

    2013-01-01

    Objectives Untreated maternal syphilis leads to adverse pregnancy outcomes. The use of point of care tests (POCT) offers an opportunity to improve screening coverage for syphilis and other aspects of health systems. Our objective is to present the experience of the introduction of POCT for syphilis in Peru and describe how new technology can catalyze health system strengthening. Methods The study was implemented from September 2009–November 2010 to assess the feasibility of the use of a POCT for syphilis for screening pregnant women in Lima, Peru. Outcomes measured included access to syphilis screening, treatment coverage, partner treatment, effect on patient flow and service efficiency, acceptability among providers and patients, and sustainability. Results Before the introduction of POCT, a pregnant woman needed 6 visits to the health center in 27 days before she received her syphilis result. We trained 604 health providers and implemented the POCT for syphilis as the “two for one strategy”, offering with one finger stick both syphilis and HIV testing. Implementation of the POCT resulted in testing and treatment on the first visit. Screening and treatment coverages for syphilis improved significantly compared with the previous year. Implementation of POCT has been scaled up nationally since the study ended, and coverages for screening, treatment and partner treatment have remained over 92%. Conclusions Implementation of POCT for syphilis proved feasible and acceptable, and led to improvement in several aspects of health services. For the process to be effective we highlight the importance of: (1) engaging the authorities; (2) dissipating tensions between providers and identifying champions; (3) training according to the needs; (4) providing monitoring, supervision, support and recognition; (5) sharing results and discussing actions together; (6) consulting and obtaining feedback from users; and (7) integrating with other services such as with rapid HIV

  11. 2D-QSPR/DFT studies of aryl-substituted PNP-Cr-based catalyst systems for highly selective ethylene oligomerization.

    PubMed

    Tang, Siyang; Liu, Zhen; Zhan, Xingwen; Cheng, Ruihua; He, Xuelian; Liu, Boping

    2014-03-01

    1-Hexene and 1-octene are important comonomers for the synthesis of high performance polyolefins. Recently, various N-substituted Cr-bis(diphenylphosphino)amine (PNP-Cr) catalysts show the potential as excellent candidates for highly selective ethylene trimerization/tetramerization. In this work, a series of aryl-substituted PNP-Cr catalysts were studied by two-dimensional quantitative structure-property relationship (QSPR) method based on density functional theory (DFT) calculations. The heuristic method (HM) and best multi-linear regression (BMLR) were used to establish the best linear regression models to describe the relationship between selectivities and catalyst structures. Both Cr(I) and Cr(II) active site models for ethylene trimerization/tetramerization were considered. It was found that 1) the relativity and stability of the models were increased by using self-defined descriptors based on DFT calculations; 2) Cr(I)/Cr(III) centers were the most plausible active sites for ethylene trimerization, while Cr(II)/Cr(IV) active sites were most possibly responsible for ethylene tetramerization; and 3) the skeleton structures of the PNP-Cr system with good complanation and symmetry were crucial for achieving excellent catalytic selectivity of 1-octene, while the PNP-Cr backbone with a large steric effect on N atom would benefit ethylene trimerization. Six new PNP ligands with high selectivity toward ethylene trimerization/tetramerization were predicted based on descriptor analysis and the best linear regression models providing a good basis for further development of novel catalyst systems with better performance.

  12. Electrochemical catalyst recovery method

    DOEpatents

    Silva, Laura J.; Bray, Lane A.

    1995-01-01

    A method of recovering catalyst material from latent catalyst material solids includes: a) combining latent catalyst material solids with a liquid acid anolyte solution and a redox material which is soluble in the acid anolyte solution to form a mixture; b) electrochemically oxidizing the redox material within the mixture into a dissolved oxidant, the oxidant having a potential for oxidation which is effectively higher than that of the latent catalyst material; c) reacting the oxidant with the latent catalyst material to oxidize the latent catalyst material into at least one oxidized catalyst species which is soluble within the mixture and to reduce the oxidant back into dissolved redox material; and d) recovering catalyst material from the oxidized catalyst species of the mixture. The invention is expected to be particularly useful in recovering spent catalyst material from petroleum hydroprocessing reaction waste products having adhered sulfides, carbon, hydrocarbons, and undesired metals, and as well as in other industrial applications.

  13. Electrochemical catalyst recovery method

    DOEpatents

    Silva, L.J.; Bray, L.A.

    1995-05-30

    A method of recovering catalyst material from latent catalyst material solids includes: (a) combining latent catalyst material solids with a liquid acid anolyte solution and a redox material which is soluble in the acid anolyte solution to form a mixture; (b) electrochemically oxidizing the redox material within the mixture into a dissolved oxidant, the oxidant having a potential for oxidation which is effectively higher than that of the latent catalyst material; (c) reacting the oxidant with the latent catalyst material to oxidize the latent catalyst material into at least one oxidized catalyst species which is soluble within the mixture and to reduce the oxidant back into dissolved redox material; and (d) recovering catalyst material from the oxidized catalyst species of the mixture. The invention is expected to be particularly useful in recovering spent catalyst material from petroleum hydroprocessing reaction waste products having adhered sulfides, carbon, hydrocarbons, and undesired metals, and as well as in other industrial applications. 3 figs.

  14. Dealloying of Cu-Based Metallic Glasses in Acidic Solutions: Products and Energy Storage Applications

    PubMed Central

    Wang, Zhifeng; Liu, Jiangyun; Qin, Chunling; Yu, Hui; Xia, Xingchuan; Wang, Chaoyang; Zhang, Yanshan; Hu, Qingfeng; Zhao, Weimin

    2015-01-01

    Dealloying, a famous ancient etching technique, was used to produce nanoporous metals decades ago. With the development of dealloying techniques and theories, various interesting dealloying products including nanoporous metals/alloys, metal oxides and composites, which exhibit excellent catalytic, optical and sensing performance, have been developed in recent years. As a result, the research on dealloying products is of great importance for developing new materials with superior physical and chemical properties. In this paper, typical dealloying products from Cu-based metallic glasses after dealloying in hydrofluoric acid and hydrochloric acid solutions are summarized. Several potential application fields of these dealloying products are discussed. A promising application of nanoporous Cu (NPC) and NPC-contained composites related to the energy storage field is introduced. It is expected that more promising dealloying products could be developed for practical energy storage applications. PMID:28347030

  15. System for continuously and catalytically removing arsenic from shale oil and regenerating the catalyst

    SciTech Connect

    Goyal, S.K.

    1989-04-25

    A system is described for producing and upgrading shale oil, comprising: (a) an oil shale retort for liberating a gaseous effluent stream containing hydrocarbons, residual amounts of arsenic and retort water vapor; (b) means connected to the retort for receiving the effluent stream, and recovering a liquid containing shale oil, arsenic and retort water; (c) separator means connected to the liquid recovery means for receiving the liquid and separating the shale oil arsenic from the retort water; (d) retort water purification means connected to the separator means for receiving and substantially purifying the retort water; (e) a first guard bed containing an arsenic-removing absorber; (f) a second guard bed containing an arsenic-removing absorber; (g) a first means interconnecting the separator means with each of the guard beds and having a first valve means for alternately directing a flow of the shale oil and arsenic through each of the guard beds; (h) a second means interconnecting the retort water purification means with each of the guard beds and having a second value means for alternately directing a flow of the purified retort water through each of the guard beds in opposite phase relationship to the flow of shade oil and arsenic through each of the guard beds.

  16. Ceria nanoclusters on graphene/Ru(0001): A new model catalyst system

    DOE PAGES

    Novotny, Z.; Netzer, F. P.; Dohnalek, Z.

    2016-03-22

    In this study, the growth of ceria nanoclusters on single-layer graphene on Ru(0001) has been examined, with a view towards fabricating a stable system for model catalysis studies. The surface morphology and cluster distribution as a function of oxide coverage and substrate temperature has been monitored by scanning tunneling microscopy (STM), whereas the chemical composition of the cluster deposits has been determined by Auger electron spectroscopy (AES). The ceria nanoparticles are of the CeO2(111)-type and are anchored at the intrinsic defects of the graphene surface, resulting in a variation of the cluster densities across the macroscopic sample surface. The ceriamore » clusters on graphene display a remarkable stability against reduction in ultrahigh vacuum up to 900 K, but some sintering of clusters is observed for temperatures > 450 K. The evolution of the cluster size distribution suggests that the sintering proceeds via a Smoluchowski ripening mechanism, i.e. diffusion and aggregation of entire clusters.« less

  17. Microstructure-strength relationships of heavily deformed Cu-based composites

    SciTech Connect

    Trybus, C.L.

    1988-07-01

    Heavily deformed Cu-based composites attain anomalous increases in strength upon mechanical deformation. The unique filamentary microstructures that evolve during processing (cold rolling, wire drawing or swaging) are the source of the strengthening. Composite strength is correlated to microstructural characteristics for arc melted Cu-20 vol.% Nb cold rolled up to a true strain of 6.9. During rolling Nb elongates and becomes ribbon-like while the Cu matrix undergoes a cycle of deformation-dynamic recovery-recrystallization which allows for the further reduction of the Nb. Longitudinal and transverse specimens have equivalent mechanical properties. The ultimate tensile strength of the sheet showed a weak dependence on Nb filament spacing and its strength is controlled by a dislocation propagation mechanism. TEM analysis of the composite sheet substructure revealed dislocation densities of 1-2 /times/ 10/sup 10//cm/sup 2/. TEM sample preparation of Cu by ion-thinning was found to increase the dislocation density of annealed Cu by more than 400% but had a relatively small effect on heavily worked Cu. The orientations and textures of Cu and Nb in the composite are evaluated by TEM. The feasibility of producing heavily deformed Cu-based composites via powder metallurgical processing techniques is explored because of the wider range of composite compositions which can be produced in contrast with ingot metallurgy. Specifically, the mechanical and microstructural characteristics of hot extruded elemental Cu and Nb powders and Cu-Nb powders pre-alloyed by the rotating electrode process are examined. 103 refs., 54 figs., 8 tabs.

  18. Catalytic hydrodechlorination of trichloroethylene in a novel NaOH/2-propanol/methanol/water system on ceria-supported Pd and Rh catalysts.

    PubMed

    Cobo, Martha; Becerra, Jorge; Castelblanco, Miguel; Cifuentes, Bernay; Conesa, Juan A

    2015-08-01

    The catalytic hydrodechlorination (HDC) of high concentrations of trichloroethylene (TCE) (4.9 mol%, 11.6 vol%) was studied over 1%Pd, 1%Rh and 0.5%Pd-0.5%Rh catalysts supported on CeO2 under conditions of room temperature and pressure. For this, a one-phase system of NaOH/2-propanol/methanol/water was designed with molar percentages of 13.2/17.5/36.9/27.6, respectively. In this system, the alcohols delivered the hydrogen required for the reaction through in-situ dehydrogenation reactions. PdRh/CeO2 was the most active catalyst for the degradation of TCE among the evaluated materials, degrading 85% of the trichloroethylene, with alcohol dehydrogenation rates of 89% for 2-propanol and 83% for methanol after 1 h of reaction. Fresh and used catalysts were characterized by Transmission Electron Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS), and Thermogravimetric analysis (TGA). These results showed important differences of the active phase in each catalyst sample. Rh/CeO2 had particle sizes smaller than 1 nm and the active metal was partially oxidized (Rh(0)/Rh(+δ) ratio of 0.43). This configuration showed to be suitable for alcohols dehydrogenation. On the contrary, Pd/CeO2 showed a Pd completed oxidized and with a mean particle size of 1.7 nm, which seemed to be unfavorable for both, alcohols dehydrogenation and TCE HDC. On PdRh/CeO2, active metals presented a mean particle size of 2.7 nm and more reduced metallic species, with ratios of Rh(0)/Rh(+δ) = 0.67 and Pd(0)/Pd(+δ) = 0.28, which showed to be suitable features for the TCE HDC. On the other hand, TGA results suggested some deposition of NaCl residues over the catalyst surfaces. Thus, the new reaction system using PdRh/CeO2 allowed for the degradation of high concentrations of the chlorinated compound by using in situ hydrogen liquid donors in a reaction at room temperature and pressure.

  19. Low-temperature catalytic oxidative coupling of methane in an electric field over a Ce–W–O catalyst system

    NASA Astrophysics Data System (ADS)

    Sugiura, Kei; Ogo, Shuhei; Iwasaki, Kousei; Yabe, Tomohiro; Sekine, Yasushi

    2016-04-01

    We examined oxidative coupling of methane (OCM) over various Ce–W–O catalysts at 423 K in an electric field. Ce2(WO4)3/CeO2 catalyst showed high OCM activity. In a periodic operation test over Ce2(WO4)3/CeO2 catalyst, C2 selectivity exceeded 60% during three redox cycles. However, Ce2(WO4)3/CeO2 catalyst without the electric field showed low activity, even at 1073 K: CH4 Conv., 6.0%; C2 Sel., 2.1%. A synergetic effect between the Ce2(WO4)3 structure and electric field created the reactive oxygen species for selective oxidation of methane. Results of XAFS, in-situ Raman and periodic operation tests demonstrated that OCM occurred as the lattice oxygen in Ce2(WO4)3 (short W–O bonds in distorted WO4 unit) was consumed. The consumed oxygen was reproduced by a redox mechanism in the electric field.

  20. Low-temperature catalytic oxidative coupling of methane in an electric field over a Ce-W-O catalyst system.

    PubMed

    Sugiura, Kei; Ogo, Shuhei; Iwasaki, Kousei; Yabe, Tomohiro; Sekine, Yasushi

    2016-04-27

    We examined oxidative coupling of methane (OCM) over various Ce-W-O catalysts at 423 K in an electric field. Ce2(WO4)3/CeO2 catalyst showed high OCM activity. In a periodic operation test over Ce2(WO4)3/CeO2 catalyst, C2 selectivity exceeded 60% during three redox cycles. However, Ce2(WO4)3/CeO2 catalyst without the electric field showed low activity, even at 1073 K: CH4 Conv., 6.0%; C2 Sel., 2.1%. A synergetic effect between the Ce2(WO4)3 structure and electric field created the reactive oxygen species for selective oxidation of methane. Results of XAFS, in-situ Raman and periodic operation tests demonstrated that OCM occurred as the lattice oxygen in Ce2(WO4)3 (short W-O bonds in distorted WO4 unit) was consumed. The consumed oxygen was reproduced by a redox mechanism in the electric field.

  1. Low-temperature catalytic oxidative coupling of methane in an electric field over a Ce–W–O catalyst system

    PubMed Central

    Sugiura, Kei; Ogo, Shuhei; Iwasaki, Kousei; Yabe, Tomohiro; Sekine, Yasushi

    2016-01-01

    We examined oxidative coupling of methane (OCM) over various Ce–W–O catalysts at 423 K in an electric field. Ce2(WO4)3/CeO2 catalyst showed high OCM activity. In a periodic operation test over Ce2(WO4)3/CeO2 catalyst, C2 selectivity exceeded 60% during three redox cycles. However, Ce2(WO4)3/CeO2 catalyst without the electric field showed low activity, even at 1073 K: CH4 Conv., 6.0%; C2 Sel., 2.1%. A synergetic effect between the Ce2(WO4)3 structure and electric field created the reactive oxygen species for selective oxidation of methane. Results of XAFS, in-situ Raman and periodic operation tests demonstrated that OCM occurred as the lattice oxygen in Ce2(WO4)3 (short W–O bonds in distorted WO4 unit) was consumed. The consumed oxygen was reproduced by a redox mechanism in the electric field. PMID:27118726

  2. Method for reactivating catalysts and a method for recycling supercritical fluids used to reactivate the catalysts

    DOEpatents

    Ginosar, Daniel M.; Thompson, David N.; Anderson, Raymond P.

    2008-08-05

    A method of reactivating a catalyst, such as a solid catalyst or a liquid catalyst. The method comprises providing a catalyst that is at least partially deactivated by fouling agents. The catalyst is contacted with a fluid reactivating agent that is at or above a critical point of the fluid reactivating agent and is of sufficient density to dissolve impurities. The fluid reactivating agent reacts with at least one fouling agent, releasing the at least one fouling agent from the catalyst. The at least one fouling agent becomes dissolved in the fluid reactivating agent and is subsequently separated or removed from the fluid reactivating agent so that the fluid reactivating agent may be reused. A system for reactivating a catalyst is also disclosed.

  3. A comparison study of toluene removal by two-stage DBD-catalyst systems loading with MnO(x), CeMnO(x), and CoMnO(x).

    PubMed

    Huang, Yifan; Dai, Shaolong; Feng, Fada; Zhang, Xuming; Liu, Zhen; Yan, Keping

    2015-12-01

    This paper studies the toluene removal by a two-stage dielectric barrier discharge (DBD)-catalyst system with three catalysts: MnO(x)/ZSM-5, CoMnO(x)/ZSM-5, and CeMnO(x)/ZSM-5. V-Q Lissajous method, Brunauer-Emmett-Teller (BET) surface area, X-ray diffraction (XRD), and X-ray photoelectron (XPS) are used to characterize the DBD and catalysts. The DBD processing partially oxidizes the toluene, and the removal efficiency has a linear relationship with ozone generation. Three DBD-catalyst systems are compared in terms of their toluene removal efficiency, Fourier transform infrared (FTIR) spectra, carbon balance, CO selectivity, CO2 selectivity, and ozone residual. The results show that the DBD-catalyst system with CoMnO(x)/ZSM-5 performs better than the other two systems. It has the highest removal efficiency of about 93.7%, and the corresponding energy yield is 4.22 g/kWh. The carbon balance and CO2 selectivity of CoMnO(x)/ZSM-5 is also better than the other two catalysts. The measurements of two important byproducts including aerosols and ozone are also presented.

  4. Formation of alumina-nickel-molybdenum catalysts

    SciTech Connect

    Erofeev, V.I.; Basov, V.G.; Vagin, A.I.; Kalechits, I.V.

    1982-06-01

    On the basis of the results obtained in physical and chemical studies of alumina-nickel-molybdenum oxide catalysts as well as binary system and the individual oxides, the conclusions show that the commercial catalyst consists mainly of nickel and aluminium molybdates, aluminium molybdates, molybdenum oxide, and the alumina support. 4 figures.

  5. Nanostructured catalysts for organic transformations.

    PubMed

    Chng, Leng Leng; Erathodiyil, Nandanan; Ying, Jackie Y

    2013-08-20

    and/or recyclability of the nanostructured catalysts via control of the structure, composition of the catalytically active NPs, and/or nature of the support. These principles will aid researchers in the rational design and engineering of new types of multifunctional nanocatalysts for the achievement of green and sustainable chemical processes. Although the past decade has brought many advances, there are still challenges in the area of nanocatalysis that need to be addressed. These include loss of catalytic activity during operation due to sintering, leaching of soluble species from the nanocatalysts under harsh reaction conditions, loss of control over well-defined morphologies during the scale-up synthesis of the nanocomposites, and limited examples of enantioselective nanocatalytic systems. The future of nanocatalyst research lies in the judicious design and development of nanocomposite catalysts that are stable and resistant to sintering and leaching, and yet are highly active and enantioselective for the desired catalytic organic transformations, even after multiple runs. The successful generation of such multifunctional nanocatalysts especially in tandem, domino, or cascade reactions would provide a powerful tool for the establishment of green and sustainable technologies.

  6. Microreactor for efficient catalyst evaluation

    NASA Astrophysics Data System (ADS)

    Besser, Ronald S.; Ouyang, Sean; Surangalikar, Harshal; Prevot, Michelle

    2001-09-01

    This paper describes ongoing work in the development of microreactor-based systems for applications in the chemical process industry. The microreactors discussed here are formed from silicon using robust micromachining processes to produce devices with micrometer-scale fluidic structures including passageways for the introduction and removal of gases, and a reaction zone with a thin-film catalyst. We describe experiments done to characterize these reactors for use as development tools for industrial catalytic processes in terms of catalyst screening, acquisition of rate laws, and determination of optimal process conditions. The system studied here, the reaction of a cyclic olefin (cyclohexene) with hydrogen in the presence of platinum catalyst, is a model for industrially important catalytic hydrogenation and dehydrogenation reactions.

  7. Integrated control of wood destroying basidiomycetes combining Cu-based wood preservatives and Trichoderma spp.

    PubMed

    Ribera, Javier; Fink, Siegfried; Bas, Maria Del Carmen; Schwarze, Francis W M R

    2017-01-01

    The production of new generation of wood preservatives (without addition of a co-biocide) in combination with an exchange of wood poles on identical sites with high fungal inoculum, has resulted in an increase of premature failures of wood utility poles in the last decades. Wood destroying basidiomycetes inhabiting sites where poles have been installed, have developed resistance against wood preservatives. The objective of the in vitro studies was to identify a Trichoderma spp. with a highly antagonistic potential against wood destroying basidiomycetes that is capable of colonizing Cu-rich environments. For this purpose, the activity of five Trichoderma spp. on Cu-rich medium was evaluated according to its growth and sporulation rates. The influence of the selected Trichoderma spp. on wood colonization and degradation by five wood destroying basidiomycetes was quantitatively analyzed by means of dry weight loss of wood specimens. Furthermore, the preventative effect of the selected Trichoderma spp. in combination with four Cu-based preservatives was also examined by mass loss and histological changes in the wood specimens. Trichoderma harzianum (T-720) was considered the biocontrol agent with higher antagonistic potential to colonize Cu-rich environments (up to 0.1% CuSO4 amended medium). T. harzianum demonstrated significant preventative effect on wood specimens against four wood destroying basidiomycetes. The combined effect of T. harzianum and Cu-based wood preservatives demonstrated that after 9 months incubation with two wood destroying basidiomycetes, wood specimens treated with 3.8 kg m-3 copper-chromium had weight losses between 55-65%, whereas containers previously treated with T. harzianum had significantly lower weight losses (0-25%). Histological studies on one of the wood destroying basidiomycetes revealed typical decomposition of wood cells by brown-rot fungi in Cu-impregnated samples, that were notably absent in wood specimens previously exposed to T

  8. Direct Synthesis of Renewable Dodecanol and Dodecane with Methyl Isobutyl Ketone over Dual-Bed Catalyst Systems.

    PubMed

    Sheng, Xueru; Li, Ning; Li, Guangyi; Wang, Wentao; Wang, Aiqin; Cong, Yu; Wang, Xiaodong; Zhang, Tao

    2017-03-09

    For the first time, we demonstrated two integrated processes for the direct synthesis of dodecanol or 2,4,8-trimethylnonane (a jet fuel range C12 -branched alkane) using methyl isobutyl ketone (MIBK) that can be derived from lignocellulose. The reactions were carried out in dual-bed continuous flow reactors. In the first bed, MIBK was selectively converted to a mixture of C12 alcohol and ketone. Over the Pd-modified magnesium- aluminium hydrotalcite (Pd-MgAl-HT) catalyst, a high total carbon yield (73.0 %) of C12 oxygenates can be achieved under mild conditions. In the second bed, the C12 oxygenates generated in the first bed were hydrogenated to dodecanol over a Ru/C catalyst or hydrodeoxygenated to 2,4,8-trimethylnonane over a Cu/SiO2 catalyst. The as-obtained dodecanol can be used as feedstock in the production of sodium dodecylsulfate (SDS) and sodium dodecyl benzene sulfonate (SDBS), which are widely used as surfactants or detergents. The asobtained 2,4,8-trimethylnonane can be blended into conventional jet fuel without hydroisomerization.

  9. Lewis Base Catalysts 6: Carbene Catalysts

    PubMed Central

    Moore, Jennifer L.

    2013-01-01

    The use of N-heterocyclic carbenes as catalysts for organic transformations has received increased attention in the past 10 years. A discussion of catalyst development and nucleophilic characteristics precedes a description of recent advancements and new reactions using N-heterocyclic carbenes in catalysis. PMID:21494949

  10. Deactivation of Oxidation Catalysts

    DTIC Science & Technology

    1991-05-01

    the fresh catalyst . The loss in chromium may be related to the formation of volatile chromium oxychlorde which vaporizes from the catalyst . It is...CeO2 only marginally improved the thtrmal stability. The addition of 2% water vapor inhibited the oxidation of ethanol for all three copper catalysts ...original activity. Field tests of a copper chromite catalyst on process gas containing H2S, methyl mercaptan, n-aldehydes, and furfural showed

  11. Ethanol synthesis and water gas shift over bifunctional sulfide catalysts

    SciTech Connect

    Klier, K.; Herman, R.G.; Richards-Babb, M.

    1992-06-01

    During this quarter, the high pressure (up to 100 atm), high temperature (up to 350{degrees}C) catalyst testing system was rebuilt with clean tubing, etc. A new preparation of MoS{sub 2} catalyst was carried out, and this catalyst will be doped with alkali and tested during the next quarter of research.

  12. Syngas Conversion to Gasoline-Range Hydrocarbons over Pd/ZnO/Al2O3 and ZSM-5 Composite Catalyst System

    SciTech Connect

    Dagle, Robert A.; Lizarazo Adarme, Jair A.; Lebarbier, Vanessa MC; Gray, Michel J.; White, James F.; King, David L.; Palo, Daniel R.

    2014-07-01

    A composite Pd/ZnO/Al2O3-HZSM-5 (Si/Al=40) catalytic system was evaluated for the synthesis of gasoline-range hydrocarbons directly from synthesis gas. Bifunctional catalyst comprising PdZn metal and acid sites present the required catalytically active sites necessary for the methanol synthesis, methanol dehydration, and methanol-to-gasoline reactions. This system provides a unique catalytic pathway for the production of liquid hydrocarbons directly from syngas. However, selectivity control is difficult and poses many challenges. The composite catalytic system was evaluated under various process conditions. Investigated were the effects of temperature (310-375oC), pressure (300-1000 psig), time-on-stream (50 hrs), and gas-hour space velocity (740-2970 hr-1), using a H2/CO molar syngas ratio of 2.0. By operating at the lower end of the temperature range investigated, liquid hydrocarbon formation was favored, as was decreased amounts of undesirable light hydrocarbons. However, lower operating temperatures also facilitated undesirable CO2 formation via the water-gas shift reaction. Higher operating pressures slightly favored liquid synthesis. Operating at relatively low pressures (e.g. 300 psig) was made possible, whereas for methanol synthesis alone higher pressure are usually required to achieve similar conversion levels (e.g. 1000 psig). Thermodynamic constraints on methanol synthesis are eased by pushing the equilibrium through hydrocarbon formation. Catalytic performance was also evaluated by altering Pd and Zn composition of the Pd/ZnO/Al2O3 catalyst. Of the catalysts and conditions tested, selectivity toward liquid hydrocarbon was highest when using a 5% Pd metal loading and Pd/Zn molar ratio of 0.25 and mixed with HZMS-5, operating at 310oC and 300 psig, CO conversion was 43 % and selectivity (carbon weight basis) to hydrocarbons was 49 wt. %. Of the hydrocarbon fraction, 44wt. % was in the C5-C12 liquid product range and consisted primarily of aromatic

  13. Chemical transformations of glucose to value added products using Cu-based catalytic systems.

    PubMed

    Yepez, Alfonso; Pineda, Antonio; Garcia, Angel; Romero, Antonio A; Luque, Rafael

    2013-08-07

    Cu nanoparticles have been supported by two types of aluminosilicate materials with and without Zn in their composition in view of their application in the microwave-assisted conversion of glucose to valuable products via tandem formic acid-promoted dehydration (to 5-hydroxymethylfurfural--HMF) and further selective hydrogenation to 5-methylfurfuryl alcohol (MFA). Results show that interesting selectivities (up to 60% to MFA or HMF) could be achieved after short times of reaction (typically 2-30 min) using Cu-containing nanomaterials. Zn was found to play an interesting role in the selectivity to reduced products, even if present in very small quantities (0.2 wt%).

  14. Tethered catalysts for the hydration of carbon dioxide

    SciTech Connect

    Valdez, Carlos A; Satcher, Jr., Joe H; Aines, Roger D; Wong, Sergio E; Baker, Sarah E; Lightstone, Felice C; Stolaroff, Joshuah K

    2014-11-04

    A system is provided that substantially increases the efficiency of CO.sub.2 capture and removal by positioning a catalyst within an optimal distance from the air-liquid interface. The catalyst is positioned within the layer determined to be the highest concentration of carbon dioxide. A hydrophobic tether is attached to the catalyst and the hydrophobic tether modulates the position of the catalyst within the liquid layer containing the highest concentration of carbon dioxide.

  15. Performance of vegetative and fruits Zn/Cu based electrochemical cell

    NASA Astrophysics Data System (ADS)

    Khan, Md. Kamrul Alam, Prof. _., Dr.

    2017-01-01

    We have studied the performance of PKL, Aloe Vera, Tomato and Lemon juice electrochemical Cells without load condition for 1:1 Zn/Cu based electrodes. It was studied the variation of Open circuit voltage (Voc), Short current (Isc) and Maximum Power (Pmax) with the variation of time for PKL, Aloe Vera, Tomato and Lemon juice electrochemical Cells. It was seen from the research observation that the discharge characteristic of the PKL electrochemical cell was more efficient than the other three Aloe Vera, Tomato and Lemon juice electrochemical Cells. Because the Open circuit voltage (Voc), Short current (Isc) and Maximum Power (Pmax) are more stable and steady than the others three Aloe Vera, Tomato and Lemon juice electrochemical Cells. Furthermore, to enhance the performance we have also studied the secondary salt effect by using the NaCl as an electrolyte with the PKL, Aloe Vera and Lemon juice electrochemical Cells. Most of the results have been tabulated and graphically discussed. I am grateful to the authority of the Science and technology ministry,Bangladesh for financial support during the research work.

  16. Development of industrial catalysts for sustainable chlorine production.

    PubMed

    Mondelli, Cecilia; Amrute, Amol P; Moser, Maximilian; Schmidt, Timm; Pérez-Ramírez, Javier

    2012-01-01

    The heterogeneously catalyzed gas-phase oxidation of HCl to Cl(2) offers an energy-efficient and eco- friendly route to recover chlorine from HCl-containing byproduct streams in the chemical industry. This process has attracted renewed interest in the last decade due to an increased chlorine demand and the growing excess of byproduct HCl from chlorination processes. Since its introduction (by Deacon in 1868) and till recent times, the industrialization of this reaction has been hindered by the lack of sufficiently active and durable materials. Recently, RuO(2)-based catalysts with outstanding activity and stability have been designed and they are being implemented for large-scale Cl(2) recycling. Herein, we review the main limiting features of traditional Cu-based catalysts and survey the key steps in the development of the new generation of industrial RuO(2)-based materials. As the expansion of this technology would benefit from cheaper, but comparably robust, alternatives to RuO(2)-based catalysts, a nov el CeO(2)-based catalyst which offers promising perspectives for application in this field has been introduced.

  17. Characterization of three-way automotive catalysts

    SciTech Connect

    Kenik, E.A.; More, K.L.; LaBarge, W.

    1995-05-01

    This has been the second year of a CRADA between General Motors - AC Delco Systems (GM-ACDS) and Martin Marietta Energy Systems (MMES) aimed at improved performance/lifetime of platinum-rhodium based three-way-catalysts (TWC) for automotive emission control systems. While current formulations meet existing emission standards, higher than optimum Pt-Rh loadings are often required. In additionk, more stringent emission standards have been imposed for the near future, demanding improved performance and service life from these catalysts. Understanding the changes of TWC conversion efficiency with ageing is a critical need in improving these catalysts.

  18. Electrochemical Behavior of TiO(x)C(y) as Catalyst Support for Direct Ethanol Fuel Cells at Intermediate Temperature: From Planar Systems to Powders.

    PubMed

    Calvillo, Laura; García, Gonzalo; Paduano, Andrea; Guillen-Villafuerte, Olmedo; Valero-Vidal, Carlos; Vittadini, Andrea; Bellini, Marco; Lavacchi, Alessandro; Agnoli, Stefano; Martucci, Alessandro; Kunze-Liebhäuser, Julia; Pastor, Elena; Granozzi, Gaetano

    2016-01-13

    To achieve complete oxidation of ethanol (EOR) to CO2, higher operating temperatures (often called intermediate-T, 150-200 °C) and appropriate catalysts are required. We examine here titanium oxycarbide (hereafter TiOxCy) as a possible alternative to standard carbon-based supports to enhance the stability of the catalyst/support assembly at intermediate-T. To test this material as electrocatalyst support, a systematic study of its behavior under electrochemical conditions was carried out. To have a clear description of the chemical changes of TiOxCy induced by electrochemical polarization of the material, a special setup that allows the combination of X-ray photoelectron spectroscopy and electrochemical measurements was used. Subsequently, an electrochemical study was carried out on TiOxCy powders, both at room temperature and at 150 °C. The present study has revealed that TiOxCy is a sufficiently conductive material whose surface is passivated by a TiO2 film under working conditions, which prevents the full oxidation of the TiOxCy and can thus be considered a stable electrode material for EOR working conditions. This result has also been confirmed through density functional theory (DFT) calculations on a simplified model system. Furthermore, it has been experimentally observed that ethanol molecules adsorb on the TiOxCy surface, inhibiting its oxidation. This result has been confirmed by using in situ Fourier transform infrared spectroscopy (FTIRS). The adsorption of ethanol is expected to favor the EOR in the presence of suitable catalyst nanoparticles supported on TiOxCy.

  19. Monopropellant engine investigation for space shuttle reaction control system. Volume 3: Improvement of metal foam for catalyst retention

    NASA Technical Reports Server (NTRS)

    1975-01-01

    The retention of granular catalyst in a metal foam matrix was demonstrated to greatly increase the life capability of hydrazine monopropellant reactors. Since nickel foam used in previous tests was found to become degraded after long-term exposure the cause of degradation was examined and metal foams of improved durability were developed. The most durable foam developed was a rhodium-coated nickel foam. An all-platinum foam was found to be incompatible in a hot ammonia (hydrazine) environment. It is recommended to scale up the manufacturing process for the improved foam to produce samples sufficiently large for space shuttle APU gas generator testing.

  20. Process for magnetic beneficiating petroleum cracking catalyst

    DOEpatents

    Doctor, R.D.

    1993-10-05

    A process is described for beneficiating a particulate zeolite petroleum cracking catalyst having metal values in excess of 1000 ppm nickel equivalents. The particulate catalyst is passed through a magnetic field in the range of from about 2 Tesla to about 5 Tesla generated by a superconducting quadrupole open-gradient magnetic system for a time sufficient to effect separation of said catalyst into a plurality of zones having different nickel equivalent concentrations. A first zone has nickel equivalents of about 6,000 ppm and greater, a second zone has nickel equivalents in the range of from about 2000 ppm to about 6000 ppm, and a third zone has nickel equivalents of about 2000 ppm and less. The zones of catalyst are separated and the second zone material is recycled to a fluidized bed of zeolite petroleum cracking catalyst. The low nickel equivalent zone is treated while the high nickel equivalent zone is discarded. 1 figures.

  1. Process for magnetic beneficiating petroleum cracking catalyst

    DOEpatents

    Doctor, Richard D.

    1993-01-01

    A process for beneficiating a particulate zeolite petroleum cracking catalyst having metal values in excess of 1000 ppm nickel equivalents. The particulate catalyst is passed through a magnetic field in the range of from about 2 Tesla to about 5 Tesla generated by a superconducting quadrupole open-gradient magnetic system for a time sufficient to effect separation of said catalyst into a plurality of zones having different nickel equivalent concentrations. A first zone has nickel equivalents of about 6,000 ppm and greater, a second zone has nickel equivalents in the range of from about 2000 ppm to about 6000 ppm, and a third zone has nickel equivalents of about 2000 ppm and less. The zones of catalyst are separated and the second zone material is recycled to a fluidized bed of zeolite petroleum cracking catalyst. The low nickel equivalent zone is treated while the high nickel equivalent zone is discarded.

  2. Metal/metal oxide doped oxide catalysts having high deNOx selectivity for lean NOx exhaust aftertreatment systems

    DOEpatents

    Park, Paul W.

    2004-03-16

    A lean NOx catalyst and method of preparing the same is disclosed. The lean NOx catalyst includes a ceramic substrate, an oxide support material, preferably .gamma.-alumina, deposited on the substrate and a metal promoter or dopant introduced into the oxide support material. The metal promoters or dopants are selected from the group consisting of indium, gallium, tin, silver, germanium, gold, nickel, cobalt, copper, iron, manganese, molybdenum, chromium, cerium, vanadium, oxides thereof, and combinations thereof. The .gamma.-alumina preferably has a pore volume of from about 0.5 to about 2.0 cc/g; a surface area of between about 80 to 350 m.sup.2 /g; an average pore size diameter of between about 3 to 30 nm; and an impurity level of less than or equal to 0.2 weight percent. In a preferred embodiment the .gamma.-alumina is prepared by a sol-gel method, with the metal doping of the .gamma.-alumina preferably accomplished using an incipient wetness impregnation technique.

  3. Prelife catalysts and replicators

    PubMed Central

    Ohtsuki, Hisashi; Nowak, Martin A.

    2009-01-01

    Life is based on replication and evolution. But replication cannot be taken for granted. We must ask what there was prior to replication and evolution. How does evolution begin? We have proposed prelife as a generative system that produces information and diversity in the absence of replication. We model prelife as a binary soup of active monomers that form random polymers. ‘Prevolutionary’ dynamics can have mutation and selection prior to replication. Some sequences might have catalytic activity, thereby enhancing the rates of certain prelife reactions. We study the selection criteria for these prelife catalysts. Their catalytic efficiency must be above certain critical values. We find a maintenance threshold and an initiation threshold. The former is a linear function of sequence length, and the latter is an exponential function of sequence length. Therefore, it is extremely hard to select for prelife catalysts that have long sequences. We compare prelife catalysis with a simple model for replication. Assuming fast template-based elongation reactions, we can show that replicators have selection thresholds that are independent of their sequence length. Our calculation demonstrates the efficiency of replication and provides an explanation of why replication was selected over other forms of prelife catalysis. PMID:19692408

  4. Facile synthesis and characterization of trimesic acid-Cu based metal organic frameworks

    NASA Astrophysics Data System (ADS)

    Sahiner, Nurettin; Sel, Kivanc; Ozturk, Omer Faruk; Demirci, Sahin; Terzi, Gozde

    2014-09-01

    Metal-organic frameworks based on trimesic acid (TMA) as organic linker and Cu (II) as metal ions from different metal salts such as CuCl2, Cu(NO3)2, CuSO4 and Cu(CH3COOH)2 were prepared in relatively environmentally friendly media e.g., at room temperature in DI water and at the boiling point of ethanol. The prepared TMA-Cu MOFs showed very interesting porosity and optical coloring based on the source of the used metal salts and preparation medium. The prepared MOFs were characterized in terms of their porosity with BET measurements and it was found that about 850 m2/g for the MOF prepared from Cu(NO3)2 salt in ethanol. The amounts of metal ions connected to TMA were determined by atomic absorption spectroscopy measurements (AAS) after dissolution of TMA-Cu MOFs by concentrated HCl treatments. From AAS measurements the mole ratio of Cu(II) to TMA was found to vary between 1.5 and 2, depending on the source of metal ions and the solvent used during preparation. The structural analysis and thermal characterization of the prepared MOFs were done by using FT-IR and TGA analysis, respectively. Additionally, TMA-Cu based MOF disks were prepared and their conductivities were determined by I-V measurements. The conductivity of TMA-Cu MOFs was calculated to be between 8.26E-08 and 5.29E-11 S/cm.

  5. Catalyst patterning for nanowire devices

    NASA Technical Reports Server (NTRS)

    Li, Jun (Inventor); Cassell, Alan M. (Inventor); Han, Jie (Inventor)

    2004-01-01

    Nanowire devices may be provided that are based on carbon nanotubes or single-crystal semiconductor nanowires. The nanowire devices may be formed on a substrate. Catalyst sites may be formed on the substrate. The catalyst sites may be formed using lithography, thin metal layers that form individual catalyst sites when heated, collapsible porous catalyst-filled microscopic spheres, microscopic spheres that serve as masks for catalyst deposition, electrochemical deposition techniques, and catalyst inks. Nanowires may be grown from the catalyst sites.

  6. Ruthenium-based olefin metathesis catalysts bearing pH-responsive ligands: External control of catalyst solubility and activity

    NASA Astrophysics Data System (ADS)

    Balof, Shawna Lynn

    2011-12-01

    Sixteen novel, Ru-based olefin metathesis catalysts bearing pH responsive ligands were synthesized. The pH-responsive groups employed with these catalysts included dimethylamino (NMe2) modified NHC ligands as well as N-donor dimethylaminopyridine (DMAP) and 3-(o-pyridyl)propylidene ligands. These pH-responsive ligands provided the means by which the solubility and/or activity profiles of the catalysts produced could be controlled via acid addition. The main goal of this dissertation was to design catalyst systems capable of performing ring opening metathesis (ROMP) and ring closing metathesis (RCM) reactions in both organic and aqueous media. In an effort to quickly gain access to new catalyst structures, a template synthesis for functionalized NHC ligand precursors was designed, in addition to other strategies, to obtain ligand precursors with ancillary NMe2 groups. Kinetic studies for the catalysts produced from these precursors showed external control of catalyst solubility was afforded via protonation of the NMe2 groups of their NHC ligands. Additionally, this protonation afforded external control of catalyst propagation rates for several catalysts. This is the first known independent external control for the propagation rates of ROMP catalysts. The incorporation of pH-responsive N-donor ligands into catalyst structures also provided the means for the external control of metathesis activity, as the protonation of these ligands resulted in an increased initiation rate based on their fast and irreversible dissociation from the metal center. The enhanced external control makes these catalysts applicable to a wide range of applications, some of which have been explored by us and/or through collaboration. Three of the catalysts designed showed remarkable metathesis activity in aqueous media. These catalysts displayed comparable RCM activity in aqueous media to a class of water-soluble catalysts reported by Grubbs et al., considered to be the most active catalyst for

  7. A fully integrated continuous-flow system for asymmetric catalysis: enantioselective hydrogenation with supported ionic liquid phase catalysts using supercritical CO(2) as the mobile phase.

    PubMed

    Hintermair, Ulrich; Franciò, Giancarlo; Leitner, Walter

    2013-04-02

    A continuous-flow process based on a chiral transition-metal complex in a supported ionic liquid phase (SILP) with supercritical carbon dioxide (scCO(2)) as the mobile phase is presented for asymmetric catalytic transformations of low-volatility organic substrates at mild reaction temperatures. Enantioselectivity of >99% ee and quantitative conversion were achieved in the hydrogenation of dimethylitaconate for up to 30 h, reaching turnover numbers beyond 100000 for the chiral QUINAPHOS-rhodium complex. By using an automated high-pressure continuous-flow setup, the product was isolated in analytically pure form without the use of any organic co-solvent and with no detectable catalyst leaching. Phase-behaviour studies and high-pressure NMR spectroscopy assisted the localisation of optimum process parameters by quantification of substrate partitioning between the IL and scCO(2). Fundamental insight into the molecular interactions of the metal complex, ionic liquid and the surface of the support in working SILP catalyst materials was gained by means of systematic variations, spectroscopic studies and labelling experiments. In concert, the obtained results provided a rationale for avoiding progressive long-term deactivation. The optimised system reached stable selectivities and productivities that correspond to 0.7 kgL(-1)h(-1) space-time yield and at least 100 kg product per gram of rhodium, thus making such processes attractive for larger-scale application.

  8. Engineering design and testing of a ground water remediation system using electrolytically generated hydrogen with a palladium catalyst for dehalogenation of chlorinated hydrogen

    SciTech Connect

    Ruiz, R.

    1997-12-01

    Recent studies have shown that dissolved hydrogen causes rapid dehalogenation of chlorinated hydrocarbons in the presence of a palladium catalyst. The speed and completeness of these reactions offer advantages in designing remediation technologies for certain ground water contamination problems. However, a practical design challenge arises in the need to saturate the aqueous phase with hydrogen in an expeditious manner. To address this issue, a two-stage treatment reactor has been developed. The first stage consists of an electrolytic cell that generates hydrogen by applying a voltage potential across the influent water stream. The second stage consists of a catalyst column of palladium metal supported on alumina beads. A bench-scale reactor has been used to test this design for treating ground water contaminated with trichloroethene and other chlorinated hydrocarbons. In influent streams containing contaminant concentrations up to 4 ppm, initial results confirm that destruction efficiencies greater than 95% may be achieved with residence times short enough to allow practical implementation in specially designed flow-through treatment wells. Results from the bench-scale tests are being used to design a pilot ground water treatment system.

  9. Microstructural evolution and surface properties of nanostructured Cu-based alloy by ultrasonic nanocrystalline surface modification technique

    NASA Astrophysics Data System (ADS)

    Amanov, Auezhan; Cho, In-Sik; Pyun, Young-Sik

    2016-12-01

    A nanostructured surface layer with a thickness of about 180 μm was successfully produced in Cu-based alloy using an ultrasonic nanocrystalline surface modification (UNSM) technique. Cu-based alloy was sintered onto low carbon steel using a powder metallurgy (P/M) method. Transmission electron microscope (TEM) characterization revealed that the severe plastic deformation introduced by UNSM technique resulted in nano-sized grains in the topmost surface layer and deformation twins. It was also found by atomic force microscope (AFM) observations that the UNSM technique provides a significant reduction in number of interconnected pores. The effectiveness of nanostructured surface layer on the tribological and micro-scratch properties of Cu-based alloy specimens was investigated using a ball-on-disk tribometer and micro-scratch tester, respectively. Results exhibited that the UNSM-treated specimen led to an improvement in tribological and micro-scratch properties compared to that of the sintered specimen, which may be attributed to the presence of nanostructured surface layer having an increase in surface hardness and reduction in surface roughness. The findings from this study are expected to be implemented to the automotive industry, in particular connected rod bearings and bushings in order to increase the efficiency and performance of internal combustion engines (ICEs).

  10. Enhanced Oxidation Catalysts for Water Reclamation

    NASA Technical Reports Server (NTRS)

    Jolly, Clifford D.

    1999-01-01

    This effort seeks to develop and test high-performance, long operating life, physically stable catalysts for use in spacecraft water reclamation systems. The primary goals are to a) reduce the quantity of expendable water filters used to purify water aboard spacecraft, b) to extend the life of the oxidation catalysts used for eliminating organic contaminants in the water reclamation systems, and c) reduce the weight/volume of the catalytic oxidation systems (e.g. VRA) used. This effort is targeted toward later space station utilization and will consist of developing flight-qualifiable catalysts and long-term ground tests of the catalyst prior to their utilization in flight. Fixed -bed catalytic reactors containing 5% platinum on granular activated carbon have been subjected to long-term dynamic column tests to measure catalyst stability vs throughput. The data generated so far indicate that an order of magnitude improvement can be obtained with the treated catalysts vs the control catalyst, at only a minor loss (approx 10%) in the initial catalytic activity.

  11. Textured catalysts and methods of making textured catalysts

    DOEpatents

    Werpy, Todd; Frye, Jr., John G.; Wang, Yong; Zacher, Alan H.

    2007-03-06

    A textured catalyst having a hydrothermally-stable support, a metal oxide and a catalyst component is described. Methods of conducting aqueous phase reactions that are catalyzed by a textured catalyst are also described. The invention also provides methods of making textured catalysts and methods of making chemical products using a textured catalyst.

  12. Integrated lipase production and in situ biodiesel synthesis in a recombinant Pichia pastoris yeast: an efficient dual biocatalytic system composed of cell free enzymes and whole cell catalysts

    PubMed Central

    2014-01-01

    Background Lipase-catalyzed biotransformation of acylglycerides or fatty acids into biodiesel via immobilized enzymes or whole cell catalysts has been considered as one of the most promising methods to produce renewable and environmentally friendly alternative liquid fuels, thus being extensively studied so far. In all previously pursued approaches, however, lipase enzymes are prepared in an independent process separated from enzymatic biodiesel production, which would unavoidably increase the cost and energy consumption during industrial manufacture of this cost-sensitive energy product. Therefore, there is an urgent need to develop novel cost-effective biocatalysts and biocatalytic processes with genuine industrial feasibility. Result Inspired by the consolidated bioprocessing of lignocellulose to generate bioethanol, an integrated process with coupled lipase production and in situ biodiesel synthesis in a recombinant P. pastoris yeast was developed in this study. The novel and efficient dual biocatalytic system based on Thermomyces lanuginosus lipase took advantage of both cell free enzymes and whole cell catalysts. The extracellular and intracellular lipases of growing yeast cells were simultaneously utilized to produce biodiesel from waste cooking oils in situ and in one pot. This integrated system effectively achieved 58% and 72% biodiesel yield via concurrent esterified-transesterified methanolysis and stepwise hydrolysis-esterification at 3:1 molar ratio between methanol and waste cooking oils, respectively. Further increasing the molar ratio of methanol to waste cooking oils to 6:1 led to an 87% biodiesel yield using the stepwise strategy. Both water tolerance and methanol tolerance of this novel system were found to be significantly improved compared to previous non-integrated biodiesel production processes using separately prepared immobilized enzymes or whole cell catalysts. Conclusion We have proposed a new concept of integrated biodiesel production

  13. Unraveling a Single-Step Simultaneous Two-Electron Transfer Process from Semiconductor to Molecular Catalyst in a CoPy/CdS Hybrid System for Photocatalytic H2 Evolution under Strong Alkaline Conditions.

    PubMed

    Xu, Yuxing; Ye, Yun; Liu, Taifeng; Wang, Xiuli; Zhang, Bingqing; Wang, Mei; Han, Hongxian; Li, Can

    2016-08-31

    Electron transfer processes from semiconductor to molecular catalysts was studied in a model hybrid photocatalytic hydrogen evolution system composed of [Co((III))(dmgH)2PyCl] (CoPy) and CdS under different pH conditions. Thermodynamic and kinetic studies revealed that photocatalytic H2 evolution under high pH conditions (pH 13.5) can only account for the thermodynamically more favorable single-step simultaneous two-electron transfer from photoirradiated CdS to Co(III)Py to produce unavoidable intermediate Co(I)Py, rather than a two-step successive one-electron transfer process. This finding not only provides new insight into the charge transfer processes between semiconductors and molecular catalysts but also opens up a new avenue for the assembly and optimization of semiconductor-molecular catalyst hybrid systems processed through multielectron transfer processes.

  14. Light alkane conversion processes - Suprabiotic catalyst systems for selective oxidation of light alkane gases to fuel oxygenates

    SciTech Connect

    Lyons, J.E.

    1992-01-01

    The objective of the work presented in this paper is to develop new, efficient catalysts for the selective transformation of the light alkanes in natural gas to alcohols for use as liquid transportation fuels, fuel precursors and chemical products. There currently exists no DIRECT one-step catalytic air-oxidation process to convert these substrates to alcohols. Such a one-step route would represent superior useful technology for the utilization of natural gas and similar refinery-derived light hydrocarbon streams. Processes for converting natural gas or its components (methane, ethane, propane, and the butanes) to alcohols for use as motor fuels, fuel additives or fuel precursors will not only add a valuable alternative to crude oil but will produce a clean-burning, high octane alternative to conventional gasoline.

  15. Light alkane conversion processes - Suprabiotic catalyst systems for selective oxidation of light alkane gases to fuel oxygenates.

    SciTech Connect

    Lyons, J.E.

    1992-07-01

    The objective of the work presented in this paper is to develop new, efficient catalysts for the selective transformation of the light alkanes in natural gas to alcohols for use as liquid transportation fuels, fuel precursors and chemical products. There currently exists no DIRECT one-step catalytic air-oxidation process to convert these substrates to alcohols. Such a one-step route would represent superior useful technology for the utilization of natural gas and similar refinery-derived light hydrocarbon streams. Processes for converting natural gas or its components (methane, ethane, propane, and the butanes) to alcohols for use as motor fuels, fuel additives or fuel precursors will not only add a valuable alternative to crude oil but will produce a clean-burning, high octane alternative to conventional gasoline.

  16. Catalyst Alloys Processing

    NASA Astrophysics Data System (ADS)

    Tan, Xincai

    2014-10-01

    Catalysts are one of the key materials used for diamond formation at high pressures. Several such catalyst products have been developed and applied in China and around the world. The catalyst alloy most widely used in China is Ni70Mn25Co5 developed at Changsha Research Institute of Mining and Metallurgy. In this article, detailed techniques for manufacturing such a typical catalyst alloy will be reviewed. The characteristics of the alloy will be described. Detailed processing of the alloy will be presented, including remelting and casting, hot rolling, annealing, surface treatment, cold rolling, blanking, finishing, packaging, and waste treatment. An example use of the catalyst alloy will also be given. Industrial experience shows that for the catalyst alloy products, a vacuum induction remelt furnace can be used for remelting, a metal mold can be used for casting, hot and cold rolling can be used for forming, and acid pickling can be used for metal surface cleaning.

  17. Self-organization of Cu-based immiscible alloys under irradiation: An atom-probe tomography study

    NASA Astrophysics Data System (ADS)

    Stumphy, Brad D.

    The stability of materials subjected to prolonged irradiation has been a topic of renewed interest in recent years due to the projected growth of nuclear power as an alternative energy source. The irradiating particles impart energy into the material, thereby causing atomic displacements to occur. These displacements result in the creation of point defects and the random ballistic mixing of the atoms. Consequently, the material is driven away from its equilibrium structure. The supersaturation of defects can lead to the degradation of mechanical properties, but a high density of internal interfaces, which act as defect sinks, will suppress the supersaturation and long-range transport of defects. The microstructural evolution of the material is controlled by the ballistic mixing as well as the mobility of the point defects. In immiscible alloys, these two processes compete against one another, as the ballistic mixing acts to solutionize the alloy components, and the thermal diffusion of the large number of defects acts to phase separate the components. The work presented in this dissertation examines the effect of heavy-ion irradiation on immiscible, binary Cu-based alloys. Dilute alloys of Cu-Fe, Cu-V, and V-Cu have been subjected to irradiation, and atom-probe tomography has been utilized in order to better understand the complex nature of the response of these simple model systems to an irradiation environment. The results show that a steady-state, nano-scale patterning structure, with a high density of unsaturable defect sinks, can be maintained under prolonged irradiation. Additionally, precipitation from a supersaturated solid solution is shown to be a function of both the thermal diffusion and the ballistic mixing. Solvent-rich secondary precipitates, termed "cherry-pits," are observed inside of the solute-rich primary precipitates. Through a combination of simulation work and analyzing multiple alloys experimentally, it was determined that this cherry

  18. Methods of making textured catalysts

    DOEpatents

    Werpy, Todd; Frye, Jr., John G.; Wang, Yong; Zacher, Alan H.

    2010-08-17

    A textured catalyst having a hydrothermally-stable support, a metal oxide and a catalyst component is described. Methods of conducting aqueous phase reactions that are catalyzed by a textured catalyst are also described. The invention also provides methods of making textured catalysts and methods of making chemical products using a textured catalyst.

  19. Stereospecific olefin polymerization catalysts

    DOEpatents

    Bercaw, John E.; Herzog, Timothy A.

    1998-01-01

    A metallocene catalyst system for the polymerization of .alpha.-olefins to yield stereospecific polymers including syndiotactic, and isotactic polymers. The catalyst system includes a metal and a ligand of the formula ##STR1## wherein: R.sup.1, R.sup.2, and R.sup.3 are independently selected from the group consisting of hydrogen, C.sub.1 to C.sub.10 alkyl, 5 to 7 membered cycloalkyl, which in turn may have from 1 to 3 C.sub.1 to C.sub.10 alkyls as a substituent, C.sub.6 to C.sub.15 aryl or arylalkyl in which two adjacent radicals may together stand for cyclic groups having 4 to 15 carbon atoms which in turn may be substituted, or Si(R.sup.8).sub.3 where R.sup.8 is selected from the group consisting of C.sub.1 to C.sub.10 alkyl, C.sub.6 to C.sub.15 aryl or C.sub.3 to C.sub.10 cycloalkyl; R.sup.4 and R.sup.6 are substituents both having van der Waals radii larger than the van der Waals radii of groups R.sup.1 and R.sup.3 ; R.sup.5 is a substituent having a van der Waals radius less than about the van der Waals radius of a methyl group; E.sup.1, E.sup.2 are independently selected from the group consisting of Si(R.sup.9).sub.2, Si(R.sup.9).sub.2 --Si(R.sup.9).sub.2, Ge(R.sup.9).sub.2, Sn(R.sup.9).sub.2, C(R.sup.9).sub.2, C(R.sup.9).sub.2 --C(R.sup.9).sub.2, where R.sup.9 is C.sub.1 to C.sub.10 alkyl, C.sub.6 to C.sub.15 aryl or C.sub.3 to C.sub.10 cycloalkyl; and the ligand may have C.sub.S or C.sub.1 -symmetry. Preferred metals are selected from the group consisting of group III, group IV, group V or lanthanide group elements. The catalysts are used to prepare stereoregular polymers including polypropylene from .alpha.-olefin monomers.

  20. Stereospecific olefin polymerization catalysts

    DOEpatents

    Bercaw, J.E.; Herzog, T.A.

    1998-01-13

    A metallocene catalyst system is described for the polymerization of {alpha}-olefins to yield stereospecific polymers including syndiotactic, and isotactic polymers. The catalyst system includes a metal and a ligand of the formula shown wherein: R{sup 1}, R{sup 2}, and R{sup 3} are independently selected from the group consisting of hydrogen, C{sub 1} to C{sub 10} alkyl, 5 to 7 membered cycloalkyl, which in turn may have from 1 to 3 C{sub 1} to C{sub 10} alkyls as a substituent, C{sub 6} to C{sub 15} aryl or arylalkyl in which two adjacent radicals may together stand for cyclic groups having 4 to 15 carbon atoms which in turn may be substituted, or Si(R{sup 8}){sub 3} where R{sup 8} is selected from the group consisting of C{sub 1} to C{sub 10} alkyl, C{sub 6} to C{sub 15} aryl or C{sub 3} to C{sub 10} cycloalkyl; R{sup 4} and R{sup 6} are substituents both having van der Waals radii larger than the van der Waals radii of groups R{sup 1} and R{sup 3}; R{sup 5} is a substituent having a van der Waals radius less than about the van der Waals radius of a methyl group; E{sup 1}, E{sup 2} are independently selected from the group consisting of Si(R{sup 9}){sub 2}, Si(R{sup 9}){sub 2}--Si(R{sup 9}){sub 2}, Ge(R{sup 9}){sub 2}, Sn(R{sup 9}){sub 2}, C(R{sup 9}){sub 2}, C(R{sup 9}){sub 2}--C(R{sup 9}){sub 2}, where R{sup 9} is C{sub 1} to C{sub 10} alkyl, C{sub 6} to C{sub 15} aryl or C{sub 3} to C{sub 10} cycloalkyl; and the ligand may have C{sub S} or C{sub 1}-symmetry. Preferred metals are selected from the group consisting of group III, group IV, group V or lanthanide group elements. The catalysts are used to prepare stereoregular polymers including polypropylene from {alpha}-olefin monomers.

  1. Liquefaction with microencapsulated catalysts

    DOEpatents

    Weller, Sol W.

    1985-01-01

    A method of dispersing a liquefaction catalyst within coal or other carbonaceous solids involves providing a suspension in oil of microcapsules containing the catalyst. An aqueous solution of a catalytic metal salt is emulsified in the water-immiscible oil and the resulting minute droplets microencapsulated in polymeric shells by interfacial polycondensation. The catalyst is subsequently blended and dispersed throughout the powdered carbonaceous material to be liquefied. At liquefaction temperatures the polymeric microcapsules are destroyed and the catalyst converted to minute crystallites in intimate contact with the carbonaceous material.

  2. Polyolefin catalyst manufacturing

    SciTech Connect

    Inkrott, K.E.; Scinta, J.; Smith, P.D. )

    1989-10-16

    Statistical process control (SPC) procedures are absolutely essential for making new-generation polyolefin catalysts with the consistent high quality required by modern polyolefin processes. Stringent quality assurance is critical to the production of today's high-performance catalysts. Research and development efforts during the last 20 years have led to major technological improvements in the polyolefin industry. New generation catalysts, which once were laboratory curiosities, must now be produced commercially on a regular and consistent basis to meet the increasing requirements of the plastics manufacturing industry. To illustrate the more stringent requirements for producing the new generation polyolefin catalysts, the authors compare the relatively simple, first-generation polypropylene catalyst production requirements with some of the basic requirements of manufacturing a more complex new-generation catalyst, such as Catalyst Resources Inc.'s LYNX 900. The principles which hold true for the new-generation catalysts such as LYNX 900 are shown to apply equally to the scale-up of other advanced technology polyolefin catalysts.

  3. METHOD OF PURIFYING CATALYSTS

    DOEpatents

    Joris, G.G.

    1958-09-01

    It has been fuund that the presence of chlorine as an impurity adversely affects the performance of finely divided platinum catalysts such as are used in the isotopic exchange process for the production of beavy water. This chlorine impurity may be removed from these catalysts by treating the catalyst at an elevated temperature with dry hydrogen and then with wet hydrogen, having a hydrogen-water vapor volume of about 8: 1. This alternate treatment by dry hydrogen and wet hydrogen is continued until the chlorine is largely removed from the catalyst.

  4. Development and performance of Cu-based oxygen carriers for chemical-looping combustion

    SciTech Connect

    Chuang, S.Y.; Dennis, J.S.; Hayhurst, A.N.; Scott, S.A.

    2008-07-15

    Chemical-looping combustion (CLC) has the inherent property of separating the product CO{sub 2} from flue gases. Instead of air, it uses an oxygen carrier, usually in the form of a metal oxide, to provide oxygen for combustion. This paper focuses on the development and performance of a suitable Cu-based oxygen carrier for burning solid fuels using CLC. Carriers were made from CuO and Al{sub 2}O{sub 3} (as a support) in three different ways: mechanical mixing, wet impregnation, and co-precipitation. The reactivity of these solids was assessed by measuring their ability to oxidize CO, when in a hot bed of sand fluidized by a mixture of CO and N{sub 2}. After that, the Cu in the carrier was oxidized back to CuO by fluidizing the hot bed with air. These oxygen carriers were tested over many such cycles of reduction and oxidation. This work confirms that supporting CuO on Al{sub 2}O{sub 3} enhances the ability of the resulting particles to withstand mechanical and thermal stresses in a fluidized bed. Also, only co-precipitation produces particles that have a high loading of copper and do not agglomerate at 800-900 C. The performance of co-precipitated particles of CuO/Al{sub 2}O{sub 3} at oxidizing CO to CO{sub 2} was significantly affected by the pH of the solution in which precipitation occurred: a high pH (9.7) gave particles that reacted completely and rapidly. After 18 cycles, such a co-precipitated carrier with 82.5 wt% CuO yielded all its oxygen when oxidizing CO. X-ray analysis showed that when heated, CuO reacted with Al{sub 2}O{sub 3} to form CuAl{sub 2}O{sub 4}, which was fully reducible, so CuO experienced no loss in extent of reaction after forming this mixed oxide. An increase in operating temperature from 800 to 900 C led to the CuO providing slightly less oxygen; this was because a little of the CuO decomposed to Cu{sub 2}O between its reduction and oxidation, when the bed was fluidized by pure N{sub 2}. (author)

  5. Cooperation of catalysts and templates

    NASA Technical Reports Server (NTRS)

    White, D. H.; Kanavarioti, A.; Nibley, C. W.; Macklin, J. W.

    1986-01-01

    In order to understand how self-reproducing molecules could have originated on the primitive Earth or extraterrestrial bodies, it would be useful to find laboratory models of simple molecules which are able to carry out processes of catalysis and templating. Furthermore, it may be anticipated that systems in which several components are acting cooperatively to catalyze each other's synthesis will have different behavior with respect to natural selection than those of purely replicating systems. As the major focus of this work, laboratory models are devised to study the influence of short peptide catalysts on template reactions which produce oligonucleotides or additional peptides. Such catalysts could have been the earliest protoenzymes of selective advantage produced by replicating oligonucleotides. Since this is a complex problem, simpler systems are also studied which embody only one aspect at a time, such as peptide formation with and without a template, peptide catalysis of nontemplated peptide synthesis, and model reactions for replication of the type pioneered by Orgel.

  6. OsO(4) in ionic liquid [Bmim]PF(6): a recyclable and reusable catalyst system for olefin dihydroxylation. remarkable effect of DMAP.

    PubMed

    Yao, Qingwei

    2002-06-27

    [reaction: see text] The combination of the ionic liquid [bmim]PF(6) and DMAP provides a most simple and practical approach to the immobilization of OsO(4) as catalyst for olefin dihydroxylation. Both the catalyst and the ionic liquid can be repeatedly recycled and reused in the dihydroxylation of a variety of olefins with only a very slight drop in catalyst activity.

  7. Elucidating the interaction between Ni and CeOx in ethanol steam reforming catalysts: A perspective of recent studies over model and powder systems

    DOE PAGES

    Liu, Zongyuan; Senanayake, Sanjaya D.; Rodriguez, Jose A.

    2016-11-15

    Bulk metallic nickel is a poor catalyst for the reforming of oxygenates being deactivated by the deposition of coke. In contrast, Ni-ceria is an active system for the catalytic extraction of H2 from the ethanol steam reforming reaction (ESR, C2H5OH + 3H2O ↔ 2CO2 + 6H2). Numerous studies, with model (well-defined crystal surfaces) and technical (high surface area powders) catalysts, have been devoted to understand the fundamental role of each catalyst component, the performance of adjacent sites in the metal-oxide interface, and the complex mechanistic steps that convert two oxygenated reactants (ethanol and H2O) into H2. The size and lowmore » loading of Ni on ceria facilitate metal-oxide support interactions that probably enhance the reactivity of the system. To establish the precise role of both Ni and Ce is challenging. However it is clear that both Ni and Ce are associated with the dissociation of H2O (OH + H), while ceria readily adsorbs and partially dissociates ethanol (i.e. ethoxy formation). The most difficult step of Csingle bondC bond dissociation likely occurs only on Ni or at the Ni-Ce interface. H2O and OH remain as important agents for the prevention of excess C build up during the C—H/C—C dissociation process. Often, deactivation upon C build up, is a direct result of Ni sintering and decoupling of the Ni-Ce interactions. One strategy to maintain good activity and stability is to protect the Ni-Ce interaction, and this can be achieved through the use of solid solutions (Ce1–xNixO2–y) or by employing stabilizing agents such as W (NixWyCezO2). In this study, we present and discuss the most recent work for the ESR reaction and show the important role of ceria which participates directly in the reaction and also enhances catalytic activity through metal-support interactions.« less

  8. Elucidating the interaction between Ni and CeOx in ethanol steam reforming catalysts: A perspective of recent studies over model and powder systems

    SciTech Connect

    Liu, Zongyuan; Senanayake, Sanjaya D.; Rodriguez, Jose A.

    2016-11-15

    Bulk metallic nickel is a poor catalyst for the reforming of oxygenates being deactivated by the deposition of coke. In contrast, Ni-ceria is an active system for the catalytic extraction of H2 from the ethanol steam reforming reaction (ESR, C2H5OH + 3H2O ↔ 2CO2 + 6H2). Numerous studies, with model (well-defined crystal surfaces) and technical (high surface area powders) catalysts, have been devoted to understand the fundamental role of each catalyst component, the performance of adjacent sites in the metal-oxide interface, and the complex mechanistic steps that convert two oxygenated reactants (ethanol and H2O) into H2. The size and low loading of Ni on ceria facilitate metal-oxide support interactions that probably enhance the reactivity of the system. To establish the precise role of both Ni and Ce is challenging. However it is clear that both Ni and Ce are associated with the dissociation of H2O (OH + H), while ceria readily adsorbs and partially dissociates ethanol (i.e. ethoxy formation). The most difficult step of Csingle bondC bond dissociation likely occurs only on Ni or at the Ni-Ce interface. H2O and OH remain as important agents for the prevention of excess C build up during the C—H/C—C dissociation process. Often, deactivation upon C build up, is a direct result of Ni sintering and decoupling of the Ni-Ce interactions. One strategy to maintain good activity and stability is to protect the Ni-Ce interaction, and this can be achieved through the use of solid solutions (Ce1–xNixO2–y) or by employing stabilizing agents such as W (NixWyCezO2). In this study, we present and discuss the most recent work for the ESR reaction and show the important role of ceria which participates directly in the reaction and also enhances catalytic activity through metal-support interactions.

  9. Aqueous Biphasic Systems for the Synthesis of Formates by Catalytic CO2 Hydrogenation: Integrated Reaction and Catalyst Separation for CO2 -Scrubbing Solutions.

    PubMed

    Scott, Martin; Blas Molinos, Beatriz; Westhues, Christian; Franciò, Giancarlo; Leitner, Walter

    2017-03-22

    Aqueous biphasic systems were investigated for the production of formate-amine adducts by metal-catalyzed CO2 hydrogenation, including typical scrubbing solutions as feedstocks. Different hydrophobic organic solvents and ionic liquids could be employed as the stationary phase for cis-[Ru(dppm)2 Cl2 ] (dppm=bis-diphenylphosphinomethane) as prototypical catalyst without any modification or tagging of the complex. The amines were found to partition between the two phases depending on their structure, whereas the formate-amine adducts were nearly quantitatively extracted into the aqueous phase, providing a favorable phase behavior for the envisaged integrated reaction/separation sequence. The solvent pair of methyl isobutyl carbinol (MIBC) and water led to the most practical and productive system and repeated use of the catalyst phase was demonstrated. The highest single batch activity with a TOFav of approximately 35 000 h(-1) and an initial TOF of approximately 180 000 h(-1) was achieved in the presence of NEt3 . Owing to higher stability, the highest productivities were obtained with methyl diethanolamine (Aminosol CST 115) and monoethanolamine (MEA), which are used in commercial scale CO2 -scrubbing processes. Saturated aqueous solutions (CO2 overpressure 5-10 bar) of MEA could be converted into the corresponding formate adducts with average turnover frequencies up to 14×10(3)  h(-1) with an overall yield of 70 % based on the amine, corresponding to a total turnover number of 150 000 over eleven recycling experiments. This opens the possibility for integrated approaches to carbon capture and utilization.

  10. Advanced Petroleum-Based Fuels - Diesel Emissions Project (APBF-DEC): 2,000-Hour Performance of a NOx Adsorber Catalyst and Diesel Particle Filter System for a Medium-Duty, Pick-Up Diesel Engine Platform; Final Report

    SciTech Connect

    Not Available

    2007-03-01

    Presents the results of a 2,000-hour test of an emissions control system consisting of a nitrogen oxides adsorber catalyst in combination with a diesel particle filter, advanced fuels, and advanced engine controls in an SUV/pick-up truck vehicle platform.

  11. Nano-catalysts: Bridging the gap between homogeneous and heterogeneous catalysis

    EPA Science Inventory

    Functionalized nanoparticles have emerged as sustainable alternatives to conventional materials, as robust, high-surface-area heterogeneous catalyst supports. We envisioned a catalyst system, which can bridge the homogenous and heterogeneous system. Postsynthetic surface modifica...

  12. Recombination Catalysts for Hypersonic Fuels

    NASA Technical Reports Server (NTRS)

    Chinitz, W.

    1998-01-01

    The goal of commercially-viable access to space will require technologies that reduce propulsion system weight and complexity, while extracting maximum energy from the products of combustion. This work is directed toward developing effective nozzle recombination catalysts for the supersonic and hypersonic aeropropulsion engines used to provide such access to space. Effective nozzle recombination will significantly reduce rk=le length (hence, propulsion system weight) and reduce fuel requirements, further decreasing the vehicle's gross lift-off weight. Two such catalysts have been identified in this work, barium and antimony compounds, by developing chemical kinetic reaction mechanisms for these materials and determining the engine performance enhancement for a typical flight trajectory. Significant performance improvements are indicated, using only 2% (mole or mass) of these compounds in the combustor product gas.

  13. Fischer-Tropsch Catalysts

    NASA Technical Reports Server (NTRS)

    White, James H. (Inventor); Taylor, Jesse W. (Inventor)

    2008-01-01

    Catalyst compositions and methods for F-T synthesis which exhibit high CO conversion with minor levels (preferably less than 35% and more preferably less than 5%) or no measurable carbon dioxide generation. F-T active catalysts are prepared by reduction of certain oxygen deficient mixed metal oxides.

  14. Nanostructured catalyst supports

    DOEpatents

    Zhu, Yimin; Goldman, Jay L.; Qian, Baixin; Stefan, Ionel C.

    2012-10-02

    The present invention relates to SiC nanostructures, including SiC nanopowder, SiC nanowires, and composites of SiC nanopowder and nanowires, which can be used as catalyst supports in membrane electrode assemblies and in fuel cells. The present invention also relates to composite catalyst supports comprising nanopowder and one or more inorganic nanowires for a membrane electrode assembly.

  15. Nanostructured catalyst supports

    DOEpatents

    Zhu, Yimin; Goldman, Jay L.; Qian, Baixin; Stefan, Ionel C.

    2015-09-29

    The present invention relates to SiC nanostructures, including SiC nanopowder, SiC nanowires, and composites of SiC nanopowder and nanowires, which can be used as catalyst supports in membrane electrode assemblies and in fuel cells. The present invention also relates to composite catalyst supports comprising nanopowder and one or more inorganic nanowires for a membrane electrode assembly.

  16. Reducible oxide based catalysts

    DOEpatents

    Thompson, Levi T.; Kim, Chang Hwan; Bej, Shyamal K.

    2010-04-06

    A catalyst is disclosed herein. The catalyst includes a reducible oxide support and at least one noble metal fixed on the reducible oxide support. The noble metal(s) is loaded on the support at a substantially constant temperature and pH.

  17. Catalysts and process for liquid hydrocarbon fuel production

    SciTech Connect

    White, Mark G.; Ranaweera, Samantha A.; Henry, William P.

    2016-08-02

    The present invention provides a novel process and system in which a mixture of carbon monoxide and hydrogen synthesis gas, or syngas, is converted into hydrocarbon mixtures composed of high quality distillates, gasoline components, and lower molecular weight gaseous olefins in one reactor or step. The invention utilizes a novel supported bimetallic ion complex catalyst for conversion, and provides methods of preparing such novel catalysts and use of the novel catalysts in the process and system of the invention.

  18. High-temperature catalyst for catalytic combustion and decomposition

    NASA Technical Reports Server (NTRS)

    Mays, Jeffrey A. (Inventor); Lohner, Kevin A. (Inventor); Sevener, Kathleen M. (Inventor); Jensen, Jeff J. (Inventor)

    2005-01-01

    A robust, high temperature mixed metal oxide catalyst for propellant composition, including high concentration hydrogen peroxide, and catalytic combustion, including methane air mixtures. The uses include target, space, and on-orbit propulsion systems and low-emission terrestrial power and gas generation. The catalyst system requires no special preheat apparatus or special sequencing to meet start-up requirements, enabling a fast overall response time. Start-up transients of less than 1 second have been demonstrated with catalyst bed and propellant temperatures as low as 50 degrees Fahrenheit. The catalyst system has consistently demonstrated high decomposition effeciency, extremely low decomposition roughness, and long operating life on multiple test particles.

  19. Hydroliquefaction of coal with supported catalysts: 1980 status review

    SciTech Connect

    Polinski, Leon M.; Stiegel, Gary J.; Tischer, Richard E.

    1981-06-01

    The objectives of the program have been to determine catalyst deactivation kinetic models and catalyst deactivation modes for supported Co-Mo and Ni-Mo catalysts used primarily in coal liquefaction via the H-COAL process. Emphasis has been on developing methods to increase catalyst usage by determining how to decrease catalyst replacement rates in the process and how to decrease catalyst poisoning. An important conclusion reached via model analysis and verified by experiment is that larger diameter (1/16 in.) catalysts resist poisoning deactivation much more than smaller (1/32 in.) catalysts over extended periods (60 to 110 hours) of time. If this trend can be verified, it gives a powerful tool for reducing catalyst replacement rate in the H-COAL ebullated bed system by factors of 2 or more. A second conclusion is that poisoning of catalysts occurs by several possible mechanisms or modes. Indirect or direct evidence of all these modes can be presented, though the relative importance of each mechanism has not been established. The modes include (a) poisoning by coking - with gradual increase in C/H ratio (more refractory coke) with time, (b) poisoning by metallization (selective/non-selective adsorption of inorganics such as Ti and Fe on the catalyst), (c) sintering - increase in larger pores/decrease in surface area, and (d) parallel poisoning by irreversible nitrogen compound adsorption.

  20. Organometallic polymerization catalysts

    SciTech Connect

    Waymouth, R.M.

    1993-12-31

    Well-defined transition metal catalysts have resulted in exciting new opportunities in polymer synthesis. The stereochemistry of vinyl polymers can be rationally controlled with choice of the appropriate catalysts. Studies with optically active catalyst precursors have revealed considerable information on the absolute stereochemistry of olefin polymerization and have led to the synthesis of novel chiral polyolefins. The development of homogeneous olefin metathesis catalysts has also led to a variety of well-defined new polymer structures with controlled molecular weight and molecular weight distribution. Recent advances in understanding the mechanisms and stereochemistry of homogeneous transition metal catalyzed polymerization will be discussed. The ability to control polymer structure through catalyst design presents exciting opportunities in the synthesis of {open_quotes}tailor-made{close_quotes} macromolecules.

  1. Protic acid immobilized on solid support as an extremely efficient recyclable catalyst system for a direct and atom economical esterification of carboxylic acids with alcohols.

    PubMed

    Chakraborti, Asit K; Singh, Bavneet; Chankeshwara, Sunay V; Patel, Alpesh R

    2009-08-21

    A convenient and clean procedure of esterification is reported by direct condensation of equimolar amounts of carboxylic acids with alcohols catalyzed by an easy to prepare catalyst system of perchloric acid immobilized on silica gel (HClO(4)-SiO(2)). The direct condensation of aryl, heteroaryl, styryl, aryl alkyl, alkyl, cycloalkyl, and long-chain aliphatic carboxylic acids with primary/secondary alkyl/cycloalkyl, allyl, propargyl, and long-chain aliphatic alcohols has been achieved to afford the corresponding esters in excellent yields. Chiral alcohol and N-t-Boc protected chiral amino acid also resulted in ester formation with the representative carboxylic acid or alcohol without competitive N-t-Boc deprotection and detrimental effect on the optical purity of the product demonstrating the mildness and chemoselectivity of the procedure. The esters of long-chain (>C(10)) acids and alcohols are obtained in high yields. The catalyst is recovered and recycled without significant loss of activity. The industrial application of the esterification process is demonstrated by the synthesis of prodrugs of ibuprofen and a few commercial flavoring agents. Other protic acids such as H(2)SO(4), HBr, TfOH, HBF(4), and TFA that were adsorbed on silica gel were less effective compared to HClO(4)-SiO(2) following the order HClO(4)-SiO(2) > H(2)SO(4)-SiO(2) > HBr-SiO(2) > TfOH-SiO(2) > HBF(4)-SiO(2) approximately TFA-SiO(2). When HClO(4) was immobilized on other solid supports the catalytic efficiency followed the order HClO(4)-SiO(2) > HClO(4)-K10 > HClO(4)-Al(2)O(3) (neutral) > HClO(4)-Al(2)O(3) (acidic) > HClO(4)-Al(2)O(3) (basic).

  2. Use of aluminum phosphate as the dehydration catalyst in single step dimethyl ether process

    DOEpatents

    Peng, Xiang-Dong; Parris, Gene E.; Toseland, Bernard A.; Battavio, Paula J.

    1998-01-01

    The present invention pertains to a process for the coproduction of methanol and dimethyl ether (DME) directly from a synthesis gas in a single step (hereafter, the "single step DME process"). In this process, the synthesis gas comprising hydrogen and carbon oxides is contacted with a dual catalyst system comprising a physical mixture of a methanol synthesis catalyst and a methanol dehydration catalyst. The present invention is an improvement to this process for providing an active and stable catalyst system. The improvement comprises the use of an aluminum phosphate based catalyst as the methanol dehydration catalyst. Due to its moderate acidity, such a catalyst avoids the coke formation and catalyst interaction problems associated with the conventional dual catalyst systems taught for the single step DME process.

  3. Synthesis and Understanding of Novel Catalysts

    SciTech Connect

    Stair, Peter C.

    2013-07-09

    The research took advantage of our capabilities to perform in-situ and operando Raman spectroscopy on complex systems along with our developing expertise in the synthesis of uniform, supported metal oxide materials to investigate relationships between the catalytically active oxide composition, atomic structure, and support and the corresponding chemical and catalytic properties. The project was organized into two efforts: 1) Synthesis of novel catalyst materials by atomic layer deposition (ALD). 2) Spectroscopic and chemical investigations of coke formation and catalyst deactivation. ALD synthesis was combined with conventional physical characterization, Raman spectroscopy, and probe molecule chemisorption to study the effect of supported metal oxide composition and atomic structure on acid-base and catalytic properties. Operando Raman spectroscopy studies of olefin polymerization leading to coke formation and catalyst deactivation clarified the mechanism of coke formation by acid catalysts.

  4. Fundamental studies of supported bimetallic catalysts by NMR spectroscopy

    SciTech Connect

    Savargaonkar, Nilesh

    1996-10-17

    Various hydrogenation reactions on transition metals are important commercially whereas certain hydrogenolysis reactions are useful from fundamental point of view. Understanding the hydrogen mobility and kinetics of adsorption-desorption of hydrogen is important in understanding the mechanisms of such reactions involving hydrogen. The kinetics of hydrogen chemisorption was studied by means of selective excitation NMR on silica supported Pt, Rh and Pt-Rh catalysts. The activation energy of hydrogen desorption was found to be lower on silica supported Pt catalysts as compared to Rh and Pt-Rh catalysts. It was found that the rates of hydrogen adsorption and desorption on Pt-Rh catalyst were similar to those on Rh catalyst and much higher as compared to Pt catalyst. The Ru-Ag bimetallic system is much simpler to study than the Pt-Rh system and serves as a model system to characterize more complicated systems such as the K/Ru system. Ag was found to decrease the amounts of adsorbed hydrogen and the hydrogen-to-ruthenium stoichiometry. Ag reduced the populations of states with low and intermediate binding energies of hydrogen on silica supported Ru catalyst. The rates of hydrogen adsorption and desorption were also lower on silica supported Ru-Ag catalyst as compared to Ru catalyst. This report contains introductory information, the literature review, general conclusions, and four appendices. An additional four chapters and one appendix have been processed separately for inclusion on the data base.

  5. Photoreduction of CO2 using [Ru(bpy)2(CO)L]n+ catalysts in biphasic solution/supercritical CO2 systems.

    PubMed

    Voyame, Patrick; Toghill, Kathryn E; Méndez, Manuel A; Girault, Hubert H

    2013-10-07

    The reduction of CO2 in a biphasic liquid-condensed gas system was investigated as a function of the CO2 pressure. Using 1-benzyl-1,4-dihydronicotinamide (BNAH) as sacrificial electron donor dissolved in a dimethylformamide-water mixture and [Ru(bpy)2(CO)L](n+) as a catalyst and [Ru(bpy)3](2+) as a photosensitizer, the reaction was found to produce a mixture of CO and formate, in total about 250 μmol after just 2 h. As CO2 pressure increases, CO formation is greatly favored, being four times greater than that of formate in aqueous systems. In contrast, formate production was independent of CO2 pressure, present at about 50 μmol. Using TEOA as a solvent instead of water created a single-phase supercritical system and greatly favored formate synthesis, but similarly increasing CO2 concentration favored the CO catalytic cycle. Under optimum conditions, a turnover number (TON) of 125 was obtained. Further investigations of the component limits led to an unprecedented TON of over 1000, and an initial turnover frequency (TOF) of 1600 h(-1).

  6. Polymerization catalyst, production and use

    SciTech Connect

    Best, S.A.

    1987-01-06

    A process is described for the polymerization of ethylene and alpha-olefins having from 1 to 2 carbon atoms of mixtures of ethylene, alpha-olefins or diolefins. The process comprises polymerizing one or more olefins in the presence of the catalyst system comprising (A) an organo aluminum cocatalyst, and (B) a vanadium-containing catalyst component obtained by sequentially treating an inert solid support material in an inert solvent with (i) a dihydrocarbyl magnesium compound, (ii) optionally an oxygen-containing compound which is an alcohol, ketone or aldehyde, (iii) a vanadium compound, and (iv) a Group IIIa metal halide. The process as above is described wherein the inert solid support material is an inorganic oxide or mixtures of inorganic oxides.

  7. Polymerization catalyst, production and use

    SciTech Connect

    Best, S.A.

    1987-04-14

    A process is described for the polymerization of ethylene and alphaolefins having from 1 to 20 carbon atoms or mixtures of ethylene, alpha-olefins or diolefins. The process comprises polymerizing one or more olefins in the presence of the catalyst system comprising (A) an organo aluminum cocatalyst, and (B) a vanadium-containing catalyst component obtained by treating an inert support material in an inert solvent with (i) a dihydrocarbyl magnesium compound or a complex or mixture of an organic dihydrocarbyl magnesium compound and an aluminum compound, (ii) optionally an oxygen-containing compound which is an alcohol, ketone or aldehyde, (iii) a Group IIIa metal halide, (iv) at least one vanadium compound, and as the last step a second treatment with a Group IIIa metal halide.

  8. Catalysts and process for liquid hydrocarbon fuel production

    DOEpatents

    White, Mark G; Liu, Shetian

    2014-12-09

    The present invention provides a novel process and system in which a mixture of carbon monoxide and hydrogen synthesis gas, or syngas, is converted into hydrocarbon mixtures composed of high quality gasoline components, aromatic compounds, and lower molecular weight gaseous olefins in one reactor or step. The invention utilizes a novel molybdenum-zeolite catalyst in high pressure hydrogen for conversion, as well as a novel rhenium-zeolite catalyst in place of the molybdenum-zeolite catalyst, and provides for use of the novel catalysts in the process and system of the invention.

  9. Two-beam Laser Brazing of Thin Sheet Steel for Automotive Industry Using Cu-base Filler Material

    NASA Astrophysics Data System (ADS)

    Mittelstädt, C.; Seefeld, T.; Reitemeyer, D.; Vollertsen, F.

    This work shows the potential of two-beam laser brazing for joining both Zn-coated steel and 22MnB5. Brazing of Zn-coated steel sheets using Cu-Si filler wire is already state of the art in car manufacturing. New press-hardened steels like 22MnB5 are more and more used in automotive industry, offering high potential to save costs and improve structural properties (reduced weight / higher stiffness). However, for joining of these ultra-high strength steels investigations are mandatory. In this paper, a novel approach using a two-beam laser brazing process and Cu-base filler material is presented. The use of Cu-base filler material leads to a reduced heat input, compared to currently applied welding processes, which may result in benefits concerning distortion, post processing and tensile strength of the joint. Reliable processing at desired high speeds is attained by means of laser-preheating. High feed rates prevent significant diffusion of copper into the base material.

  10. Catalyst for Carbon Monoxide Oxidation

    NASA Technical Reports Server (NTRS)

    Davis, Patricia; Brown, Kenneth; VanNorman, John; Brown, David; Upchurch, Billy; Schryer, David; Miller, Irvin

    2010-01-01

    In many applications, it is highly desirable to operate a CO2 laser in a sealed condition, for in an open system the laser requires a continuous flow of laser gas to remove the dissociation products that occur in the discharge zone of the laser, in order to maintain a stable power output. This adds to the operating cost of the laser, and in airborne or space applications, it also adds to the weight penalty of the laser. In a sealed CO2 laser, a small amount of CO2 gas is decomposed in the electrical discharge zone into corresponding quantities of CO and O2. As the laser continues to operate, the concentration of CO2 decreases, while the concentrations of CO and O2 correspondingly increase. The increasing concentration of O2 reduces laser power, because O2 scavenges electrons in the electrical discharge, thereby causing arcing in the electric discharge and a loss of the energetic electrons required to boost CO2 molecules to lasing energy levels. As a result, laser power decreases rapidly. The primary object of this invention is to provide a catalyst that, by composition of matter alone, contains chemisorbed water within and upon its structure. Such bound moisture renders the catalyst highly active and very long-lived, such that only a small quantity of it needs to be used with a CO2 laser under ambient operating conditions. This object is achieved by a catalyst that consists essentially of about 1 to 40 percent by weight of one or more platinum group metals (Pt, Pd, Rh, Ir, Ru, Os, Pt being preferred); about 1 to 90 percent by weight of one or more oxides of reducible metals having multiple valence states (such as Sn, Ti, Mn, Cu, and Ce, with SnO2 being preferred); and about 1 to 90 percent by weight of a compound that can bind water to its structure (such as silica gel, calcium chloride, magnesium sulfate, hydrated alumina, and magnesium perchlorate, with silica gel being preferred). Especially beneficial results are obtained when platinum is present in the

  11. Cross-coupling of diarylborinic acids and anhydrides with arylhalides catalyzed by a phosphite/N-heterocyclic carbene co-supported palladium catalyst system.

    PubMed

    Chen, Xiaofeng; Ke, Haihua; Chen, Yao; Guan, Changwei; Zou, Gang

    2012-09-07

    A highly efficient cross-coupling of diarylborinic acids and anhydrides with aryl chlorides and bromides has been effected by using a palladium catalyst system co-supported by a strong σ-donor N-heterocyclic carbene (NHC), N,N'-bis(2,6-diisopropylphenyl) imidazol-2-ylidene, and a strong π-acceptor phosphite, triphenylphosphite, in tert-BuOH in the present of K(3)PO(4)·3H(2)O. Unsymmetrical biaryls with a variety of functional groups could be obtained in good to excellent yields using as low as 0.01, 0.2-0.5, and 1 mol % palladium loadings for aryl bromides and activated and deactivated aryl chlorides, respectively, under mild conditions. A ligand synergy between the σ-donor NHC and the π-acceptor phosphite in the Pd/NHC/P(OPh)(3) catalytic system has been proposed to be responsible for the high efficacy to arylchlorides in the cross-coupling. A scalable and economical process has therefore been developed for synthesis of Sartan biphenyl from the Pd/NHC/P(OPh)(3) catalyzed cross-coupling of di(4-methylphenyl)borinic acid with 2-chlorobenzonitrile.

  12. Reclaim spent catalysts properly

    SciTech Connect

    Lassner, J.A.; Lasher, L.B.; Koppel, R.L.; Hamilton, J.N.

    1994-08-01

    Treatment of spent catalysts and metallic by products has become increasingly more complex over the last couple of years, due to tightening environmental concerns. Three options are available: (1) Reclaiming the metals and either reusing them to make new catalyst or recycling them for other uses. This is now the preferred option. A reclaiming firm is generally employed to handle the task. (2) Regeneration and reuse. While this generally is the preferred option, few commercial catalysts can be regenerated effectively and economically. (3) Landfilling. This has been the traditional route. However, stricter environmental regulations have made landfilling unattractive. To maximize the reclamation both economically and environmentally, five factors should be addressed: (1) proper planning and physical handling; (2) transportation of materials; (3) environmental concerns; (4) end uses of the catalyst; and (5) choosing the proper reclamation partner. These factors are discussed.

  13. Catalysts and method

    DOEpatents

    Taylor, Charles E.; Noceti, Richard P.

    1991-01-01

    An improved catlayst and method for the oxyhydrochlorination of methane is disclosed. The catalyst includes a pyrogenic porous support on which is layered as active material, cobalt chloride in major proportion, and minor proportions of an alkali metal chloride and of a rare earth chloride. On contact of the catalyst with a gas flow of methane, HC1 and oxygen, more than 60% of the methane is converted and of that converted more than 40% occurs as monochloromethane. Advantageously, the monochloromethane can be used to produce gasoline boiling range hydrocarbons with the recycle of HCl for further reaction. This catalyst is also of value for the production of formic acid as are analogous catalysts with lead, silver or nickel chlorides substituted for the cobalt chloride.

  14. Epoxidation catalyst and process

    DOEpatents

    Linic, Suljo; Christopher, Phillip

    2010-10-26

    Disclosed herein is a catalytic method of converting alkenes to epoxides. This method generally includes reacting alkenes with oxygen in the presence of a specific silver catalyst under conditions suitable to produce a yield of the epoxides. The specific silver catalyst is a silver nanocrystal having a plurality of surface planes, a substantial portion of which is defined by Miller indices of (100). The reaction is performed by charging a suitable reactor with this silver catalyst and then feeding the reactants to the reactor under conditions to carry out the reaction. The reaction may be performed in batch, or as a continuous process that employs a recycle of any unreacted alkenes. The specific silver catalyst has unexpectedly high selectivity for epoxide products. Consequently, this general method (and its various embodiments) will result in extraordinarily high epoxide yields heretofore unattainable.

  15. Solar-Driven Reduction of Aqueous Protons Coupled to Selective Alcohol Oxidation with a Carbon Nitride-Molecular Ni Catalyst System.

    PubMed

    Kasap, Hatice; Caputo, Christine A; Martindale, Benjamin C M; Godin, Robert; Lau, Vincent Wing-Hei; Lotsch, Bettina V; Durrant, James R; Reisner, Erwin

    2016-07-27

    Solar water-splitting represents an important strategy toward production of the storable and renewable fuel hydrogen. The water oxidation half-reaction typically proceeds with poor efficiency and produces the unprofitable and often damaging product, O2. Herein, we demonstrate an alternative approach and couple solar H2 generation with value-added organic substrate oxidation. Solar irradiation of a cyanamide surface-functionalized melon-type carbon nitride ((NCN)CNx) and a molecular nickel(II) bis(diphosphine) H2-evolution catalyst (NiP) enabled the production of H2 with concomitant selective oxidation of benzylic alcohols to aldehydes in high yield under purely aqueous conditions, at room temperature and ambient pressure. This one-pot system maintained its activity over 24 h, generating products in 1:1 stoichiometry, separated in the gas and solution phases. The (NCN)CNx-NiP system showed an activity of 763 μmol (g CNx)(-1) h(-1) toward H2 and aldehyde production, a Ni-based turnover frequency of 76 h(-1), and an external quantum efficiency of 15% (λ = 360 ± 10 nm). This precious metal-free and nontoxic photocatalytic system displays better performance than an analogous system containing platinum instead of NiP. Transient absorption spectroscopy revealed that the photoactivity of (NCN)CNx is due to efficient substrate oxidation of the material, which outweighs possible charge recombination compared to the nonfunctionalized melon-type carbon nitride. Photoexcited (NCN)CNx in the presence of an organic substrate can accumulate ultralong-lived "trapped electrons", which allow for fuel generation in the dark. The artificial photosynthetic system thereby catalyzes a closed redox cycle showing 100% atom economy and generates two value-added products, a solar chemical, and solar fuel.

  16. Solar-Driven Reduction of Aqueous Protons Coupled to Selective Alcohol Oxidation with a Carbon Nitride–Molecular Ni Catalyst System

    PubMed Central

    2016-01-01

    Solar water-splitting represents an important strategy toward production of the storable and renewable fuel hydrogen. The water oxidation half-reaction typically proceeds with poor efficiency and produces the unprofitable and often damaging product, O2. Herein, we demonstrate an alternative approach and couple solar H2 generation with value-added organic substrate oxidation. Solar irradiation of a cyanamide surface-functionalized melon-type carbon nitride (NCNCNx) and a molecular nickel(II) bis(diphosphine) H2-evolution catalyst (NiP) enabled the production of H2 with concomitant selective oxidation of benzylic alcohols to aldehydes in high yield under purely aqueous conditions, at room temperature and ambient pressure. This one-pot system maintained its activity over 24 h, generating products in 1:1 stoichiometry, separated in the gas and solution phases. The NCNCNx–NiP system showed an activity of 763 μmol (g CNx)−1 h–1 toward H2 and aldehyde production, a Ni-based turnover frequency of 76 h–1, and an external quantum efficiency of 15% (λ = 360 ± 10 nm). This precious metal-free and nontoxic photocatalytic system displays better performance than an analogous system containing platinum instead of NiP. Transient absorption spectroscopy revealed that the photoactivity of NCNCNx is due to efficient substrate oxidation of the material, which outweighs possible charge recombination compared to the nonfunctionalized melon-type carbon nitride. Photoexcited NCNCNx in the presence of an organic substrate can accumulate ultralong-lived “trapped electrons”, which allow for fuel generation in the dark. The artificial photosynthetic system thereby catalyzes a closed redox cycle showing 100% atom economy and generates two value-added products, a solar chemical, and solar fuel. PMID:27337491

  17. Preferential Carbon Monoxide Oxidation over Copper-Based Catalysts under In Situ Ball Milling.

    PubMed

    Eckert, Rene; Felderhoff, Michael; Schüth, Ferdi

    2017-02-20

    In situ ball milling of solid catalysts is a promising yet almost unexplored concept for boosting catalytic performance. The continuous preferential oxidation of CO (CO-PROX) under in situ ball milling of Cu-based catalysts such as Cu/Cr2 O3 is presented. At temperatures as low as -40 °C, considerable activity and more than 95 % selectivity were achieved. A negative apparent activation energy was observed, which is attributed to the mechanically induced generation and subsequent thermal healing of short-lived surface defects. In situ ball milling at sub-zero temperatures resulted in an increase of the CO oxidation rate by roughly 4 orders of magnitude. This drastic and highly selective enhancement of CO oxidation showcases the potential of in situ ball milling in heterogeneous catalysis.

  18. Crystalline titanate catalyst supports

    DOEpatents

    Anthony, Rayford G.; Dosch, Robert G.

    1993-01-01

    A series of new crystalline titanates (CT) are shown to have considerable potential as catalyst supports. For Pd supported catalyst, the catalytic activity for pyrene hydrogenation was substantially different depending on the type of CT, and one was substantially more active than Pd on hydrous titanium oxide (HTO). For 1-hexene hydrogenation the activities of the new CTs were approximately the same as for the hydrous metal oxide supports.

  19. Catalytic reforming catalyst

    SciTech Connect

    Buss, W.C.; Kluksdahl, H.E.

    1980-12-09

    An improved catalyst, having a reduced fouling rate when used in a catalytic reforming process, said catalyst comprising platinum disposed on an alumina support wherein the alumina support is obtained by removing water from aluminum hydroxide produced as a by-product from a ziegler higher alcohol synthesis reaction, and wherein the alumina is calcined at a temperature of 1100-1400/sup 0/F so as to have a surface area of 165 to 215 square meters per gram.

  20. Crystalline titanate catalyst supports

    DOEpatents

    Anthony, R.G.; Dosch, R.G.

    1993-01-05

    A series of new crystalline titanates (CT) are shown to have considerable potential as catalyst supports. For Pd supported catalyst, the catalytic activity for pyrene hydrogenation was substantially different depending on the type of CT, and one was substantially more active than Pd on hydrous titanium oxide (HTO). For 1-hexene hydrogenation the activities of the new CTs were approximately the same as for the hydrous metal oxide supports.

  1. Process and catalyst for carbonylating olefins

    DOEpatents

    Zoeller, Joseph Robert

    1998-06-02

    Disclosed is an improved catalyst system and process for preparing aliphatic carbonyl compounds such as aliphatic carboxylic acids, alkyl esters of aliphatic carboxylic acids and anhydrides of aliphatic carboxylic acids by carbonylating olefins in the presence of a catalyst system comprising (1) a first component selected from at least one Group 6 metal, i.e., chromium, molybdenum, and/or tungsten and (2) a second component selected from at least one of certain halides and tertiary and quaternary compounds of a Group 15 element, i.e., nitrogen, phosphorus and/or arsenic, and (3) as a third component, a polar, aprotic solvent. The process employing the improved catalyst system is carried out under carbonylating conditions of pressure and temperature discussed herein. The process constitutes and improvement over known processes since it can be carried out at moderate carbonylation conditions without the necessity of using an expensive noble metal catalyst, volatile, toxic materials such as nickel tetracarbonyl, formic acid or a formate ester. Further, the addition of a polar, aprotic solvent to the catalyst system significantly increases, or accelerates, the rate at which the carbonylation takes place.

  2. Characterization of three-way automotive catalysts

    SciTech Connect

    Kenik, E.A.; More, K.L.; LaBarge, W.

    1997-04-01

    The CRADA between Delphi Automotive Systems (Delphi; formerly General Motors - AC Delco, Systems) and Lockheed Martin Energy Research (LMER) on automotive catalysts was completed at the end of FY96, after a ten month, no-cost extension. The CRADA was aimed at improved performance and lifetime of noble metal based three-way-catalysts (TWC), which are the primary catalytic system for automotive emission control systems. While these TWC can meet the currently required emission standards, higher than optimum noble metal loadings are often required to meet lifetime requirements. In addition, more stringent emission standards will be imposed in the near future, demanding improved performance and service life from these catalysts. Understanding the changes of TWC conversion efficiency with ageing is a critical need in improving these catalysts. Initially in a fresh catalyst, the active material is often distributed on a very fine scale, approaching single atoms or small atomic clusters. As such, a wide range of analytical techniques have been employed to provide high spatial resolution characterization of the evolving state of the catalytic material.

  3. A One-Bead-One-Catalyst Approach to Aspartic Acid-Based Oxidation Catalyst Discovery

    PubMed Central

    Lichtor, Phillip A.; Miller, Scott J.

    2011-01-01

    We report an approach to the high-throughput screening of asymmetric oxidation catalysts. The strategy is based on application of the one-bead-one-compound library approach, wherein each of our catalyst candidates is based on a peptide scaffold. For this purpose we rely on a recently developed catalytic cycle that employs an acid-peracid shuttle. In order to implement our approach, we developed a compatible linker and demonstrated that the library format is amenable to screening and sequencing of catalysts employing partial Edman degradation and MALDI mass spectrometry analysis. The system was applied to the discovery (and re-discovery) of catalysts for the enantioselective oxidation of a cyclohexene derivative. The system is now poised for application to unprecedented substrate classes for asymmetric oxidation reactions. PMID:21417485

  4. Catalyst Additives to Enhance Mercury Oxidation and Capture

    SciTech Connect

    Thomas K. Gale

    2005-12-31

    Preliminary research has shown that SCR catalysts employed for nitrogen-oxide reduction can effectively oxidize mercury. Three different SCR catalysts are currently being studied in this project--honeycomb-type, plate-type, and a hybrid-type catalyst. The catalysts were manufactured and supplied by Cormetech Inc., Hitachi America Ltd., and Haldor-Topsoe Inc., respectively. Parametric testing was performed to investigate the contribution of flue-gas chemistry on mercury oxidation via SCR catalysts. Future work to characterize flue gas simulations typically derived from low and high sulfur bituminous coal are being performed in a stepwise manner, to avoid the constant interruptions in testing that occur when leaks in the system are generated during temperature transitions. Specifically, chlorine concentration vs. mercury oxidation correlations will be developed for each catalyst. The contributions of temperature are also being investigated. SO2 oxidation is also being investigated for each test condition.

  5. Transforming the Fight Against Tuberculosis: Targeting Catalysts of Transmission

    PubMed Central

    Dowdy, David W.; Azman, Andrew S.; Kendall, Emily A.; Mathema, Barun

    2014-01-01

    The global tuberculosis control community has committed itself to ambitious 10-year targets. To meet these targets, biomedical advances alone will be insufficient; a more targeted public health tuberculosis strategy is also needed. We highlight the role of “tuberculosis transmission catalysts,” defined as variabilities in human behavior, bacillary properties, and host physiology that fuel the propagation of active tuberculosis at the local level. These catalysts can be categorized as factors that increase contact rates, infectiousness, or host susceptibility. Different catalysts predominate in different epidemiological and sociopolitical settings, and public health approaches are likely to succeed only if they are tailored to target the major catalysts driving transmission in the corresponding community. We argue that global tuberculosis policy should move from a country-level focus to a strategy that prioritizes collection of data on key transmission catalysts at the local level followed by deployment of “catalyst-targeted” interventions, supported by strengthened health systems. PMID:24982034

  6. Magnetic and dendritic catalysts.

    PubMed

    Wang, Dong; Deraedt, Christophe; Ruiz, Jaime; Astruc, Didier

    2015-07-21

    The recovery and reuse of catalysts is a major challenge in the development of sustainable chemical processes. Two methods at the frontier between homogeneous and heterogeneous catalysis have recently emerged for addressing this problem: loading the catalyst onto a dendrimer or onto a magnetic nanoparticle. In this Account, we describe representative examples of these two methods, primarily from our research group, and compare them. We then describe new chemistry that combines the benefits of these two methods of catalysis. Classic dendritic catalysis has involved either attaching the catalyst covalently at the branch termini or within the dendrimer core. We have used chelating pyridyltriazole ligands to insolubilize catalysts at the termini of dendrimers, providing an efficient, recyclable heterogeneous catalysts. With the addition of dendritic unimolecular micelles olefin metathesis reactions catalyzed by commercial Grubbs-type ruthenium-benzylidene complexes in water required unusually low amounts of catalyst. When such dendritic micelles include intradendritic ligands, both the micellar effect and ligand acceleration promote faster catalysis in water. With these types of catalysts, we could carry out azide alkyne cycloaddition ("click") chemistry with only ppm amounts of CuSO4·5H2O and sodium ascorbate under ambient conditions. Alternatively we can attach catalysts to the surface of superparamagnetic iron oxide nanoparticles (SPIONs), essentially magnetite (Fe3O4) or maghemite (γ-Fe2O3), offering the opportunity to recover the catalysts using magnets. Taking advantage of the merits of both of these strategies, we and others have developed a new generation of recyclable catalysts: dendritic magnetically recoverable catalysts. In particular, some of our catalysts with a γ-Fe2O3@SiO2 core and 1,2,3-triazole tethers and loaded with Pd nanoparticles generate strong positive dendritic effects with respect to ligand loading, catalyst loading, catalytic activity and

  7. Characterisation of gold catalysts.

    PubMed

    Villa, Alberto; Dimitratos, Nikolaos; Chan-Thaw, Carine E; Hammond, Ceri; Veith, Gabriel M; Wang, Di; Manzoli, Maela; Prati, Laura; Hutchings, Graham J

    2016-09-21

    Au-based catalysts have established a new important field of catalysis, revealing specific properties in terms of both high activity and selectivity for many reactions. However, the correlation between the morphology and the activity of the catalyst is not always clear although much effort has been addressed to this task. To some extent the problem relates to the complexity of the characterisation techniques that can be applied to Au catalyst and the broad range of ways in which they can be prepared. Indeed, in many reports only a few characterization techniques have been used to investigate the potential nature of the active sites. The aim of this review is to provide a critical description of the techniques that are most commonly used as well as the more advanced characterization techniques available for this task. The techniques that we discuss are (i) transmission electron microscopy methods, (ii) X-ray spectroscopy techniques, (iii) vibrational spectroscopy techniques and (iv) chemisorption methods. The description is coupled with developing an understanding of a number of preparation methods. In the final section the example of the supported AuPd alloy catalyst is discussed to show how the techniques can gain an understanding of an active oxidation catalyst.

  8. The Information Ecology of Personal Health Record Systems: Secure Messaging as Catalyst and Its Evolving Impact on Use and Consequences

    ERIC Educational Resources Information Center

    Nazi, Kim M.

    2012-01-01

    Personal Health Records (PHRs) and PHR systems have been designed as consumer-oriented tools to empower patients and improve health care. Despite significant consumer interest and anticipated benefits, adoption remains low. Understanding the consumer perspective is necessary, but insufficient by itself. Consumer PHR use also has broad implications…

  9. CERES AuTomAted job Loading SYSTem (CATALYST): An automated workflow manager for satellite data production

    NASA Astrophysics Data System (ADS)

    Gleason, J. L.; Hillyer, T. N.; Wilkins, J.

    2012-12-01

    The CERES Science Team integrates data from 5 CERES instruments onboard the Terra, Aqua and NPP missions. The processing chain fuses CERES observations with data from 19 other unique sources. The addition of CERES Flight Model 5 (FM5) onboard NPP, coupled with ground processing system upgrades further emphasizes the need for an automated job-submission utility to manage multiple processing streams concurrently. The operator-driven, legacy-processing approach relied on manually staging data from magnetic tape to limited spinning disk attached to a shared memory architecture system. The migration of CERES production code to a distributed, cluster computing environment with approximately one petabyte of spinning disk containing all precursor input data products facilitates the development of a CERES-specific, automated workflow manager. In the cluster environment, I/O is the primary system resource in contention across jobs. Therefore, system load can be maximized with a throttling workload manager. This poster discusses a Java and Perl implementation of an automated job management tool tailored for CERES processing.

  10. Cobalt Fischer-Tropsch catalysts having improved selectivity

    DOEpatents

    Miller, James G.; Rabo, Jule A.

    1989-01-01

    A cobalt Fischer-Tropsch catalyst having an improved steam treated, acid extracted LZ-210 support is taught. The new catalyst system demonstrates improved product selectivity at Fischer-Tropsch reaction conditions evidenced by lower methane production, higher C.sub.5.sup.+ yield and increased olefin production.

  11. Chemical interactions in multimetal/zeolite catalysts

    SciTech Connect

    Sachtler, W.M.H.

    1992-12-21

    Research is proposed on two groups of zeolite based catalysts that contain two transition elements. In one group both metals are fully reduced, in the other group one element is left as a positive ion; it can act as a chemical anchor'', or as a catalyst promoter for the reduced metal. The objective is to explore the potential of such materials for designing superior catalysts for synthesis and conversion of hydrocarbons and other energy carriers. ENDOR, EXAFS, CO-FTIR and TPD will be used to identify the interaction of Mn[sup 2+] ions with Rh[sub n] particles in the same zeolite cage. EXAFS at the Kedge of Fe and Pd, FTIR and Moessbauer spectroscopy will be used to characterize Fe ions and alloyed Fe atoms in PdFe/NaHY. The catalysts will be probed with CO hydrogenation and conversion of hydrocarbons. Methods Which proved successful in our study of Y supported bimetal systems will be applied to identify the state of Pt and Cu in ZSM-5, a catalyst system holding large promise for NO abatement, even in the presence of oxygen.

  12. Supported organoiridium catalysts for alkane dehydrogenation

    DOEpatents

    Baker, R. Thomas; Sattelberger, Alfred P.; Li, Hongbo

    2013-09-03

    Solid supported organoiridium catalysts, a process for preparing such solid supported organoiridium catalysts, and the use of such solid supported organoiridium catalysts in dehydrogenation reactions of alkanes is provided. The catalysts can be easily recovered and recycled.

  13. In –Situ Spectroscopic Investigation of Immobilized Organometallic Catalysts

    SciTech Connect

    Davis, Robert, J.

    2007-11-14

    Immobilized organometallic catalysts, in principle, can give high rates and selectivities like homogeneous catalysts with the ease of separation enjoyed by heterogeneous catalysts. However, the science of immobilized organometallics has not been developed because the field lies at the interface between the homogeneous and heterogeneous catalysis communities. By assembling an interdisciplinary research team that can probe all aspects of immobilized organometallic catalyst design, the entire reacting system can be considered, where the transition metal complex, the complex-support interface and the properties of the support can all be considered simultaneously from both experimental and theoretical points of view. Researchers at Georgia Tech and the University of Virginia are studying the fundamental principles that can be used to understand and design future classes of immobilized organometallic catalysts. In the framework of the overall collaborative project with Georgia Tech, our work focused on (a) the X-ray absorption spectroscopy of an immobilized Pd-SCS-O complex (b) the mode of metal leaching from supported Pd catalysts during Heck catalysis and (c) the mode of deactivation of Jacobsen’s Co-salen catalysts during the hydrolytic kinetic resolution of terminal epoxides. Catalysts containing supported Pd pincer complexes, functionalized supports containing mercapto and amine groups, and oligomeric Co-salen catalysts were synthesized at Georgia Tech and sent to the University of Virginia. Incorporation of Pd onto several different kinds of supports (silica, mercapto-functionalized silica, zeolite Y) was performed at the University of Virginia.

  14. Catalyst reforming process

    SciTech Connect

    Swan, G.A. III

    1989-05-23

    This patent describes a process for catalytically reforming a gasoline boiling range naphtha, with hydrogen, in a semi-regenerative or semi-cyclic reforming process unit comprised of serially connected reactors, inclusive of a lead reactor and one or more downstream reactors, the last of which is the tail reactor, each of which contains a halogenated reforming catalyst comprised of a halide, a Group VIII noble metal, and an inorganic oxide support, the improvement which comprises continuously injecting into each downstream reactor a mixture of water and halide at a water to halide ratio from about 20:1 to about 60:1 wherein the specific ratio of water to halide for each individual downstream reactor is chosen so as to maintain the level of halide on catalyst in each downstream reactor from about 0.5 to 1.5 wt. % based on the total weight of the catalyst.

  15. Partial oxidation catalyst

    DOEpatents

    Krumpelt, Michael; Ahmed, Shabbir; Kumar, Romesh; Doshi, Rajiv

    2000-01-01

    A two-part catalyst comprising a dehydrogenation portion and an oxide-ion conducting portion. The dehydrogenation portion is a group VIII metal and the oxide-ion conducting portion is selected from a ceramic oxide crystallizing in the fluorite or perovskite structure. There is also disclosed a method of forming a hydrogen rich gas from a source of hydrocarbon fuel in which the hydrocarbon fuel contacts a two-part catalyst comprising a dehydrogenation portion and an oxide-ion conducting portion at a temperature not less than about 400.degree. C. for a time sufficient to generate the hydrogen rich gas while maintaining CO content less than about 5 volume percent. There is also disclosed a method of forming partially oxidized hydrocarbons from ethanes in which ethane gas contacts a two-part catalyst comprising a dehydrogenation portion and an oxide-ion conducting portion for a time and at a temperature sufficient to form an oxide.

  16. Oxide Nanocrystal Model Catalysts.

    PubMed

    Huang, Weixin

    2016-03-15

    Model catalysts with uniform and well-defined surface structures have been extensively employed to explore structure-property relationships of powder catalysts. Traditional oxide model catalysts are based on oxide single crystals and single crystal thin films, and the surface chemistry and catalysis are studied under ultrahigh-vacuum conditions. However, the acquired fundamental understandings often suffer from the "materials gap" and "pressure gap" when they are extended to the real world of powder catalysts working at atmospheric or higher pressures. Recent advances in colloidal synthesis have realized controlled synthesis of catalytic oxide nanocrystals with uniform and well-defined morphologies. These oxide nanocrystals consist of a novel type of oxide model catalyst whose surface chemistry and catalysis can be studied under the same conditions as working oxide catalysts. In this Account, the emerging concept of oxide nanocrystal model catalysts is demonstrated using our investigations of surface chemistry and catalysis of uniform and well-defined cuprous oxide nanocrystals and ceria nanocrystals. Cu2O cubes enclosed with the {100} crystal planes, Cu2O octahedra enclosed with the {111} crystal planes, and Cu2O rhombic dodecahedra enclosed with the {110} crystal planes exhibit distinct morphology-dependent surface reactivities and catalytic properties that can be well correlated with the surface compositions and structures of exposed crystal planes. Among these types of Cu2O nanocrystals, the octahedra are most reactive and catalytically active due to the presence of coordination-unsaturated (1-fold-coordinated) Cu on the exposed {111} crystal planes. The crystal-plane-controlled surface restructuring and catalytic activity of Cu2O nanocrystals were observed in CO oxidation with excess oxygen. In the propylene oxidation reaction with O2, 1-fold-coordinated Cu on Cu2O(111), 3-fold-coordinated O on Cu2O(110), and 2-fold-coordinated O on Cu2O(100) were identified

  17. Secret Lives of Catalysts Revealed

    SciTech Connect

    Salmeron, Miquel; Somorjai, Gabor

    2008-01-01

    Miquel Salmeron and Gabor Somorjai of Berkeley Lab's Materials Sciences Division discuss the first-ever glimpse of nanoscale catalysts in action. More information: http://newscenter.lbl.gov/press-releases/2008/10/21/catalysts/

  18. Aerogel derived catalysts

    SciTech Connect

    Reynolds, J. G., LLNL

    1996-12-11

    Aerogels area class of colloidal materials which have high surface areas and abundant mesoporous structure. SiO{sub 2} aerogels show unique physical, optical and structural properties. When catalytic metals are incorporated in the aerogel framework, the potential exists for new and very effective catalysts for industrial processes. Three applications of these metal-containing SiO{sub 2} aerogels as catalysts are briefly reviewed in this paper--NO{sub x} reduction, volatile organic compound destruction, and partial oxidation of methane.

  19. Process of making supported catalyst

    DOEpatents

    Schwarz, James A.; Subramanian, Somasundaram

    1992-01-01

    Oxide supported metal catalysts have an additional metal present in intimate association with the metal catalyst to enhance catalytic activity. In a preferred mode, iridium or another Group VIII metal catalyst is supported on a titania, alumina, tungsten oxide, silica, or composite oxide support. Aluminum ions are readsorbed onto the support and catalyst, and reduced during calcination. The aluminum can be added as aluminum nitrate to the iridium impregnate solution, e.g. chloroiridic acid.

  20. A simple, efficient and environmentally benign synthetic protocol for the synthesis of spirooxindoles using choline chloride-oxalic acid eutectic mixture as catalyst/solvent system.

    PubMed

    Khandelwal, Sarita; Rajawat, Anshu; Tailor, Yogesh Kumar; Kumar, Mahendra

    2014-01-01

    An efficient and environmentally benign domino protocol has been presented for the synthesis of structurally diverse spirooxindoles spiroannulated with pyranopyridopyrimidines, indenopyridopyrimidines, and chromenopyridopyrimidines involving three-component reaction of aminouracils, isatins and cyclic carbonyl compounds in deep eutectic solvent (choline chloride-oxalic acid: 1:1) which acts as efficient catalyst and environmentally benign reaction medium. The present protocol offers several advantages such as operational simplicity with easy workup, shorter reaction times excellent yields with superior atom economy and environmentally benign reaction conditions with the use of cost-effective, recyclable, non-toxic and bio-degradable DES as catalyst/solvent.

  1. Steric hindrance in a MnSalen expoxidation catalyst

    SciTech Connect

    Jun, K.W.; Wilson, R.B. Jr.; Asaro, M.F.

    1995-12-31

    Many transition metal epoxidation catalysts use porphyrin type ligands, as biomimetic models for the well-studied monooxygenase, Cyt P-450. Recently, non-porphyrin systems based on the Salen ligand have received attention, because high e.e. values are reported using chiral Salen ligands. These systems have yet to be rendered generally practical, however, because the catalyst lifetimes are very short and the turnover numbers low. The original Mn(III) Salen epoxidation catalysts became inactive within 1 h, showing only 5 to 10 turnovers. The modified, chiral Mn(III) Salen complexes show similarly low turnovers. The principal decomposition routes of the MnSalen epoxidation catalysts are not clear. The purpose of the present study is to determine whether incorporation of extreme steric hindrance into the Salen ligand could be used to increase the lifetime of the Mn(III) Salen epoxidation catalysts.

  2. Nuclearity and cooperativity effects in binuclear catalysts and cocatalysts for olefin polymerization.

    PubMed

    Li, Hongbo; Marks, Tobin J

    2006-10-17

    A series of bimetallic organo-group 4 "constrained geometry" catalysts and binuclear bisborane and bisborate cocatalysts have been synthesized to probe catalyst center-catalyst center cooperativity effects on olefin enchainment in homogenous olefin polymerization and copolymerization processes. Significant nuclearity effects are found versus mononuclear controls, and the effect can be correlated with metal-metal approach distances and ion pairing effects. Novel polymer structures can be obtained by using such binuclear catalyst/cocatalyst systems.

  3. Catalyst cartridge for carbon dioxide reduction unit

    NASA Technical Reports Server (NTRS)

    Holmes, R. F. (Inventor)

    1973-01-01

    A catalyst cartridge, for use in a carbon dioxide reducing apparatus in a life support system for space vehicles, is described. The catalyst cartridge includes an inner perforated metal wall, an outer perforated wall space outwardly from the inner wall, a base plate closing one end of the cartridge, and a cover plate closing the other end of the cartridge. The cover plate has a central aperture through which a supply line with a heater feeds a gaseous reaction mixture comprising hydrogen and carbon dioxide at a temperature from about 1000 to about 1400 F. The outer surfaces of the internal wall and the inner surfaces of the outer wall are lined with a ceramic fiber batting material of sufficient thickness to prevent carbon formed in the reaction from passing through it. The portion of the surfaces of the base and cover plates defined within the inner and outer walls are also lined with ceramic batting. The heated reaction mixture passes outwardly through the inner perforated wall and ceramic batting and over the catalyst. The solid carbon product formes is retained within the enclosure containing the catalyst. The solid carbon product formed is retained within the enclosure containing the catalyst. The water vapor and unreacted carbon dioxide and any intermediate products pass through the perforations of the outer wall.

  4. Homogeneous catalyst formulations for methanol production

    DOEpatents

    Mahajan, Devinder; Sapienza, Richard S.; Slegeir, William A.; O'Hare, Thomas E.

    1990-01-01

    There is disclosed synthesis of CH.sub.3 OH from carbon monoxide and hydrogen using an extremely active homogeneous catalyst for methanol synthesis directly from synthesis gas. The catalyst operates preferably between 100.degree.-150.degree. C. and preferably at 100-150 psia synthesis gas to produce methanol. Use can be made of syngas mixtures which contain considerable quantities of other gases, such as nitrogen, methane or excess hydrogen. The catalyst is composed of two components: (a) a transition metal carbonyl complex and (b) an alkoxide component. In the simplest formulation, component (a) is a complex of nickel tetracarbonyl and component (b) is methoxide (CH.sub.3 O.sup.13 ), both being dissolved in a methanol solvent system. The presence of a co-solvent such as p-dioxane, THF, polyalcohols, ethers, hydrocarbons, and crown ethers accelerates the methanol synthesis reaction.

  5. Homogeneous catalyst formulations for methanol production

    DOEpatents

    Mahajan, Devinder; Sapienza, Richard S.; Slegeir, William A.; O'Hare, Thomas E.

    1991-02-12

    There is disclosed synthesis of CH.sub.3 OH from carbon monoxide and hydrogen using an extremely active homogeneous catalyst for methanol synthesis directly from synthesis gas. The catalyst operates preferably between 100.degree.-150.degree. C. and preferably at 100-150 psia synthesis gas to produce methanol. Use can be made of syngas mixtures which contain considerable quantities of other gases, such as nitrogen, methane or excess hydrogen. The catalyst is composed of two components: (a) a transition metal carbonyl complex and (b) an alkoxide component. In the simplest formulation, component (a) is a complex of nickel tetracarbonyl and component (b) is methoxide (CH.sub.3 O.sup.-), both being dissolved in a methanol solvent system. The presence of a co-solvent such as p-dioxane, THF, polyalcohols, ethers, hydrocarbons, and crown ethers accelerates the methanol synthesis reaction.

  6. Ship-in-a-bottle catalysts

    DOEpatents

    Haw, James F.; Song, Weiguo

    2006-07-18

    In accordance with the present invention there is provided a novel catalyst system in which the catalytic structure is tailormade at the nanometer scale using the invention's novel ship-in-a-bottle synthesis techniques. The invention describes modified forms of solid catalysts for use in heterogeneous catalysis that have a microporous structure defined by nanocages. Examples include zeolites, SAPOs, and analogous materials that have the controlled pore dimensions and hydrothermal stability required for many industrial processes. The invention provides for modification of these catalysts using reagents that are small enough to pass through the windows used to access the cages. The small reagents are then reacted to form larger molecules in the cages.

  7. Catalysts comprising magnesium and a transition metal

    SciTech Connect

    Bujadoux, K.

    1984-10-09

    A catalyst comprising the product obtained by bringing into contact a compound of magnesium comprising at least one species selected from the group consisting of magnesium monohalides (MgX), halo-magnesium hydrides (HMgX) and magnesium hydride (MgH/sub 2/), X being a halogen and the said species MgX or HMgX being obtained by thermal decomposition of a powdery organo-magnesium halide R/sub 1/MgX wherein R/sub 1/ is an organic radical; and at least one halide of a transistion metal selected from the group consisting of titanium and vanadium, the valency of said metal in said halide being lower than or equal to 3, the quantities being such that the atomic ratio of magnesium to said transistion metal is between 1 and 25, and a catalyst system including the catalyst that is suitable for use in the polymerization of olefins and particularly ethylene.

  8. Computational Design of Lignin Depolymerization Catalysts

    SciTech Connect

    Kim, S.; Chmely, S. C.; Sturgeon, M.; Katahira, R.; Paton, R. S.; Beckham, G. T.

    2012-01-01

    Lignin is a major component of plant cell walls that is typically underutilized in selective conversion strategies for renewable fuels and chemicals. The mechanisms by which thermal and catalytic treatments deconstruct lignin remain elusive, for which quantum mechanical calculations can offer fundamental insights. In this work, a computational approach has been used to elucidate the reductive deconstruction pathway of a ruthenium-catalyzed system. Transition states have been computed to determine the rate-limiting steps for a catalyst that cleaves arylether linkages. Our calculations are supported by experimental synthesis and kinetic and thermodynamic measurements of the deconstruction of model lignin dimers by a ruthenium catalyst with the ultimate objective of designing new catalysts to eventually utilize lignin in biorefineries.

  9. Protein Scaffolding for Small Molecule Catalysts

    SciTech Connect

    Baker, David

    2014-09-14

    We aim to design hybrid catalysts for energy production and storage that combine the high specificity, affinity, and tunability of proteins with the potent chemical reactivities of small organometallic molecules. The widely used Rosetta and RosettaDesign methodologies will be extended to model novel protein / small molecule catalysts in which one or many small molecule active centers are supported and coordinated by protein scaffolding. The promise of such hybrid molecular systems will be demonstrated with the nickel-phosphine hydrogenase of DuBois et. al.We will enhance the hydrogenase activity of the catalyst by designing protein scaffolds that incorporate proton relays and systematically modulate the local environment of the catalyticcenter. In collaboration with DuBois and Shaw, the designs will be experimentally synthesized and characterized.

  10. Synthesis of non-stoichiometric nanocrystalline catalysts

    SciTech Connect

    Tschoepe, A.; Ying, J.Y.

    1995-12-01

    Nanocrystalline catalysts may be synthesized by inert gas condensation method with magnetron sputtering technique. The source material is sputtered in a low Ar pressure, and nanoclusters of similar composition as the source target are collected effectively on a liquid nitrogen cooled modified ground shield. We have generated Ce, La-Ce and Cu-Ce nanoclusters by this approach, and controlled oxidized them to derive non-stoichiometric oxide catalysts. Such novel catalysts are constituted of crystallites < 10 nm, with an ultrahigh surface-to-volume ratio. Multicomponent systems can also be synthesized with excellent homogeneity by this approach, compared to traditional chemical preparation methods. Finally, the significant non-stoichiometry in oxides provides a high concentration of oxygen vacancies and superoxide adsorbed species, which is particularly useful in catalytic redox reactions, such as SO{sub 2} reduction by CO and CO oxidation.

  11. Reforming with polymetallic catalysts

    SciTech Connect

    Baird, W.C. Jr.

    1988-11-29

    This patent describes a process for catalytically reforming, with hydrogen, a hydrocarbon naphtha feed at reforming conditions, the improvement comprising contacting the naphtha feed, and hydrogen, with a halogenated, supported platinum-rhenium catalyst promoted with iridium agglomerated to exhibit a crystallinity greater than 50 percent, as measured by X-ray.

  12. Zinc sulfide liquefaction catalyst

    DOEpatents

    Garg, Diwakar

    1984-01-01

    A process for the liquefaction of carbonaceous material, such as coal, is set forth wherein coal is liquefied in a catalytic solvent refining reaction wherein an activated zinc sulfide catalyst is utilized which is activated by hydrogenation in a coal derived process solvent in the absence of coal.

  13. Salesperson, Catalyst, Manager, Leader.

    ERIC Educational Resources Information Center

    Worth, Michael J.; Asp, James W., II

    1996-01-01

    This article examines four roles of the college or university development officer: salesperson (when direct solicitation is seen as the officer's primary role); catalyst (or sales manager, adviser, expert, facilitator); manager (stressing the importance of the overall office functioning); and leader (who exerts a leadership role in the…

  14. Polymerization catalyst, production and use

    SciTech Connect

    Best, S.A.; Etherton, B.P.; Kaus, M.J.

    1989-09-12

    This patent describes a polymerization process. It comprises polymerizing ethylene, alpha-olefins of 3 to 20 carbon atoms or mixtures of ethylene and the alpha-olefins in the presence of a catalyst system. The system comprising: an organo aluminum compound of the formula AIR'''/sub eta/X'''/sub 3-eta/ wherein R''' is hydrogen, hydrocarbyl, or substituted hydrocarbyl having from 1 to 20 carbon atoms, X''' is a halogen and eta is a number from 1 to 3, and a transition metal-containing catalyst component. The component comprising the solid reaction product obtained by treating an inert solid support material in an inert solvent with an organonmetallic compound represented by the formula R/sup 1/MgR/sup 2/ wherein R/sup 1/ and R/sup 2/, which may be the same of different,contain 1 to 20 carbon atoms and are selected from alkyl group, aryl group, cycloalkyl group, aralkyl group, alkadienyl group of group; an alcohol; an acyl halide; a titanium halide; Cl/sub 2/, and prereducing the transition metal-containing product with an aluminum alkyl, with the proviso that the first two ingredients can be added to the inert solid simultaneously, as the reaction product of the first two steps or treatment with step two immediately precedes treatment with step one.

  15. Matchmaking in Catalyst-Transfer Polycondensation: Optimizing Catalysts based on Mechanistic Insight.

    PubMed

    Leone, Amanda K; McNeil, Anne J

    2016-12-20

    Catalyst-transfer polycondensation (CTP) has emerged as a useful living, chain-growth polymerization method for synthesizing conjugated (hetero)arene-based polymers with targetable molecular weights, narrow dispersities, and controllable copolymer sequences-all properties that significantly influence their performance in devices. Over the past decade, several phosphine- and carbene-ligated Ni- and Pd-based precatalysts have been shown to be effective in CTP. One current limitation is that these traditional CTP catalysts lead to nonliving, non-chain-growth behavior when complex monomer scaffolds are utilized. Because these monomers are often found in the highest-performing materials, there is a significant need to identify alternative CTP catalysts. Recent mechanistic insight into CTP has laid the foundation for designing new catalysts to expand the CTP monomer scope. Building off this insight, we have designed and implemented model systems to identify effective catalysts by understanding their underlying mechanistic behaviors and systematically modifying catalyst structures to improve their chain-growth behavior. In this Account, we describe how each catalyst parameter-the ancillary ligand(s), reactive ligand(s), and transition metal-influences CTP. As an example, ancillary ligands often dictate the turnover-limiting step of the catalytic cycle, and perhaps more importantly, they can be used to promote the formation of the key intermediate (a metal-arene associative complex) and its subsequent reactivity. The fidelity of this intermediate is central to the mechanism for the living, chain-growth polymerization. Reactive ligands, on the other hand, can be used to improve catalyst solubility and accelerate initiation. Additional advantages of the reactive ligand include providing access points for postpolymerization modification and synthesizing polymers directly off surfaces. While the most frequently used CTP catalysts contain nickel, palladium-based catalysts

  16. Effect of iron-manganese-sepiolite as heterogeneous Fenton-like catalyst on the performance and microbial community of anaerobic granular sludge treatment system.

    PubMed

    Su, Chengyuan; Li, Weiguang; Chen, Menglin; Huang, Zhi; Wu, Lei

    2016-01-01

    Both short-term and long-term exposure experiments have been carried out to investigate the influence of iron (Fe)-manganese (Mn)-sepiolite, as a heterogeneous Fenton-like catalyst, on the performance and microbial community of anaerobic granular sludge. During the short-term exposure experiments, chemical oxygen demand (COD) removal efficiency decreased from 73.1% to 64.1% with the presence of 100mg/L of catalyst. However, long-term exposure to the catalyst did not significantly affect the COD removal efficiency (81.8%) as compared to the control (83.5%). Meanwhile, the absorption peaks of coenzyme F420 in extracellular polymeric substances (EPS) of sludge samples were remarkable by excitation-emission matrix (EEM) fluorescence spectra. After long-term exposure, the presence of the catalyst increased secretions of EPS from 83.7mg/g VSS to 89.1mg/g VSS. Further investigations with high throughput sequencing indicated that the abundance of Methanosaeta increased from 57.7% to 70.4% after long-term exposure. In bacterial communities, Proteobacteria, Firmicutes, and Synergistetes were predominant.

  17. Catalytic Destruction of a Surrogate Organic Hazardous Air Pollutant as a Potential Co-benefit for Coal-fired Selective Catalyst Reduction Systems

    EPA Science Inventory

    Catalytic destruction of benzene (C6H6), a surrogate for organic hazardous air pollutants (HAPs) produced from coal combustion, was investigated using a commercial selective catalytic reduction (SCR) catalyst for evaluating the potential co-benefit of the SCR technology for reduc...

  18. Hydroprocessing catalyst composition

    SciTech Connect

    Apelian, M.R.; Degnan, T.F. Jr.; Marler, D.O.; Mazzone, D.N.

    1993-07-13

    A bifunctional hydroprocessing catalyst is described which comprises a metal component having hydrogenation/dehydrogenation functionality and a support component comprising an inorganic, non-layered, porous, crystalline phase material having pores with diameters of at least about 13 [angstrom] and exhibiting, after calcination, an X-ray diffraction pattern with at least one peak with a relative intensity of 100 at a d-spacing greater than about 18 [angstrom], the catalyst having a surface area S, where S, expressed in m[sup 2].g[sup [minus]1], is defined by the equation: S[ge]600-13.3X where X is the total metals loading in weight percent and is least 12 weight percent. A second hydroprocessing catalyst is described according to claim 1 in which the crystalline phase has a composition expressed as follows: M[sub n/q](W[sub a]X[sub b]Y[sub c]Z[sub d]O[sub h]) wherein M is one or more ions; n is the charge of the composition excluding M expressed as oxides; q is the weighted molar average valence of M; n/q is the number of moles or mole fraction of M; W is one or more divalent elements; X is one or more trivalent elements; Y is one or more tetravalent elements; Z is one or more pentavalent elements; a, b, c, and d are mole fraction of W, X, Y, and Z, respectively, h is a number of from 1 to 2.5; and (a+b+c+d) = 1. A third hydroprocessing catalyst is described according to claim 1 in which the catalyst is at least one base metal of Group VIA, VIIA or VIIIA of the Periodic Table.

  19. Molybdenum sulfide/carbide catalysts

    DOEpatents

    Alonso, Gabriel; Chianelli, Russell R.; Fuentes, Sergio; Torres, Brenda

    2007-05-29

    The present invention provides methods of synthesizing molybdenum disulfide (MoS.sub.2) and carbon-containing molybdenum disulfide (MoS.sub.2-xC.sub.x) catalysts that exhibit improved catalytic activity for hydrotreating reactions involving hydrodesulfurization, hydrodenitrogenation, and hydrogenation. The present invention also concerns the resulting catalysts. Furthermore, the invention concerns the promotion of these catalysts with Co, Ni, Fe, and/or Ru sulfides to create catalysts with greater activity, for hydrotreating reactions, than conventional catalysts such as cobalt molybdate on alumina support.

  20. Regeneration of LOHC dehydrogenation catalysts: In-situ IR spectroscopy on single crystals, model catalysts, and real catalysts from UHV to near ambient pressure

    NASA Astrophysics Data System (ADS)

    Amende, Max; Kaftan, Andre; Bachmann, Philipp; Brehmer, Richard; Preuster, Patrick; Koch, Marcus; Wasserscheid, Peter; Libuda, Jörg

    2016-01-01

    The Liquid Organic Hydrogen Carrier (LOHC) concept offers an efficient route to store hydrogen using organic compounds that are reversibly hydrogenated and dehydrogenated. One important challenge towards application of the LOHC technology at a larger scale is to minimize degradation of Pt-based dehydrogenation catalysts during long-term operation. Herein, we investigate the regeneration of Pt/alumina catalysts poisoned by LOHC degradation. We combine ultrahigh vacuum (UHV) studies on Pt(111), investigations on well-defined Pt/Al2O3 model catalysts, and near-ambient pressure (NAP) measurements on real core⿿shell Pt/Al2O3 catalyst pellets. The catalysts were purposely poisoned by reaction with the LOHC perhydro-dibenzyltoluene (H18-MSH) and with dicyclohexylmethane (DCHM) as a simpler model compound. We focus on oxidative regeneration under conditions that may be applied in real dehydrogenation reactors. The degree of poisoning and regeneration under oxidative reaction conditions was quantified using CO as a probe molecule and measured by infrared reflection-absorption spectroscopy (IRAS) and diffuse reflectance Fourier transform IR spectroscopy (DRIFTS) for planar model systems and real catalysts, respectively. We find that regeneration strongly depends on the composition of the catalyst surface. While the clean surface of a poisoned Pt(111) single crystal is fully restored upon thermal treatment in oxygen up to 700 K, contaminated Pt/Al2O3 model catalyst and core⿿shell pellet were only partially restored under the applied reaction conditions. Whereas partial regeneration on facet-like sites on supported catalysts is more facile than on Pt(111), carbonaceous deposits adsorbed at low-coordinated defect sites impede full regeneration of the Pt/Al2O3 catalysts.

  1. Testing zinc chloride as a new catalyst for direct synthesis of cellulose di- and tri-acetate in a solvent free system under microwave irradiation.

    PubMed

    El Nemr, Ahmed; Ragab, Safaa; El Sikaily, Amany

    2016-10-20

    This research demonstrates the effect of ZnCl2 as a catalyst on the esterification of commercial cotton cellulose using acetic anhydride in order to obtain di- and tri-cellulose acetates under microwave irradiation. It was discovered that microwave irradiation significantly increased the yield and reduced the reaction time. It was found that the maximum yield for cellulose triacetates was 95.83% under the reaction conditions that were as follows: 3min reaction time, 200mg of ZnCl2 catalyst and 20ml of Ac2O for 5g cellulose. However, the cellulose acetate obtained in this manner had the highest DS (2.87). The cellulose di-acetate was produced with the maximum yield of 89.97% and with the highest DS (2.69) using 25ml Ac2O, 200mg of ZnCl2 for 5g cellulose and in 3min reaction time. The effect of some factors such as the amount of used catalyst, the quantity of acetic acid anhydride and the reaction time of the esterification process have been investigated. The production of di- and tri-cellulose acetate and the degree of substitution were confirmed using Fourier-transform infrared (FTIR) and nuclear magnetic resonance (NMR). The thermal stability was investigated using thermo gravimetric analysis (TGA), differential thermal analysis (DTA) and differential scanning calorimetry (DSC). The molecular weight and the degree of polymerization were obtained using Gel Permeation Chromatography (GPC). The analysis confirmed the successful synthesis of di- and tri-cellulose acetate without degradation during the reaction; these results were found to be in contrast to some recent studies. The present study reveals that ZnCl2 is a new catalyst; it is effective as well as inexpensive and is a low toxicity catalyst for usage in cellulose esterification.

  2. Potential application of palladium nanoparticles as selective recyclable hydrogenation catalysts

    NASA Astrophysics Data System (ADS)

    Mukherjee, DebKumar

    2008-03-01

    The search for more efficient catalytic systems that might combine the advantages of both homogeneous (catalyst modulation) and heterogeneous (catalyst recycling) catalysis is one of the most exciting challenges of modern chemistry. More recently with the advances of nanochemistry, it has been possible to prepare soluble analogues of heterogeneous catalysts. These nanoparticles are generally stabilized against aggregation into larger particles by electrostatic or steric protection. Herein we demonstrate the use of room temperature ionic liquid for the stabilization of palladium nanoparticles that are recyclable catalysts for the hydrogenation of carbon-carbon double bonds and application of these catalysts to the selective hydrogenation of internal or terminal C=C bonds in unsaturated primary alcohols. The particles suspended in room temperature ionic liquid show no metal aggregation or loss of catalytic activity even on prolonged use.

  3. Apparatus and Process for Controlled Nanomanufacturing Using Catalyst Retaining Structures

    NASA Technical Reports Server (NTRS)

    Nguyen, Cattien (Inventor)

    2013-01-01

    An apparatus and method for the controlled fabrication of nanostructures using catalyst retaining structures is disclosed. The apparatus includes one or more modified force microscopes having a nanotube attached to the tip portion of the microscopes. An electric current is passed from the nanotube to a catalyst layer of a substrate, thereby causing a localized chemical reaction to occur in a resist layer adjacent the catalyst layer. The region of the resist layer where the chemical reaction occurred is etched, thereby exposing a catalyst particle or particles in the catalyst layer surrounded by a wall of unetched resist material. Subsequent chemical vapor deposition causes growth of a nanostructure to occur upward through the wall of unetched resist material having controlled characteristics of height and diameter and, for parallel systems, number density.

  4. Corrosion aspects of Ni-Cr-Fe based and Ni-Cu based steam generator tube materials

    NASA Astrophysics Data System (ADS)

    Dutta, R. S.

    2009-09-01

    This paper reviews corrosion related issues of Ni-Cr-Fe based (in a general sense) and Ni-Cu based steam generator tube materials for nuclear power plants those have been dealt with for last more than four decades along with some updated information on corrosion research. The materials include austenitic stainless steels (SSs), Alloy 600, Monel 400, Alloy 800 and Alloy 690. Compatibility related issues of these alloys are briefly discussed along with the alloy chemistry and microstructure. For austenitic SSs, stress corrosion cracking (SCC) behaviour in high temperature aqueous environments is discussed. For Alloy 600, intergranular cracking in high temperature water including hydrogen-induced intergranular cracking is highlighted along with the interactions of material in various environments. In case of Monel 400, intergranular corrosion and pitting corrosion at ambient temperature and SCC behaviour at elevated temperature are briefly described. For Alloy 800, the discussion covers SCC behaviour, surface characterization and microstructural aspects of pitting, whereas hydrogen-related issues are also highlighted for Alloy 690.

  5. Vacancy trapping by solute atoms during quenching in Cu-based dilute alloys studied by positron annihilation spectroscopy

    NASA Astrophysics Data System (ADS)

    Yabuuchi, A.; Yamamoto, Y.; Ohira, J.; Sugita, K.; Mizuno, M.; Araki, H.; Shirai, Y.

    2009-11-01

    Frozen-in vacancies and the recovery have been investigated in some Cu-based dilute alloys by using positron annihilation lifetime spectroscopy. Cu-0.5at%Sb, Cu-0.5at%Sn and Cu-0.5at%In dilute bulk alloys were quenched to ice water from 1223 K. A pure-Cu specimen was also quenched from the same temperature. As a result, no frozen-in vacancies have been detected in as-quenched pure-Cu specimen. On the other hand, as-quenched Cu-0.5at%Sb alloy contained frozen-in thermal equilibrium vacancies with concentration of 3 × 10-5. Furthermore, these frozen-in vacancies in Cu-0.5at%Sb alloy were stable until 473 K, and began to migrate at 523 K. Finally, the Cu-Sb alloy were recovered to the fully annealed state at 823 K. This thermal stability clearly implies some interaction exists between a vacancy and Sb atom and due to the interaction, thermal equilibrium vacancies are trapped by Sb atoms during quenching.

  6. Characterization of Free Volume Changes Associated with Shear Band Formation in Zr- and Cu-Based Bulk Metallic Glasses

    SciTech Connect

    Flores, K M; Glade, S C; Asoka-Kumar, P; Kanungo, B

    2003-11-14

    The free volume model for flow in metallic glasses predicts a significant increase in free volume at the onset of plastic deformation. The details of these structural changes are unclear, however, particularly during strain localization in shear bands. In this study, the free volume changes associated with inhomogeneous plastic deformation of a Cu-based bulk metallic glass were examined using positron annihilation spectroscopy (PAS). PAS results indicated that there was a distribution of free volume site sizes in both the as-quenched and rolled glasses, and that the concentration of larger sites increased with deformation. Differential scanning calorimetry (DSC) was also used to observe the glass transition behaviors of Cu- and Zr-based glasses after rolling and annealing. Annealing resulted in an increase in the height of the endothermic glass transition peak, consistent with structural relaxation relative to the as-quenched material. Deformation resulted in both a lower endothermic peak height and an earlier and deeper exothermic peak associated with structural relaxation, indicating a more disordered structure with more free volume.

  7. Application of a mixed metal oxide catalyst to a metallic substrate

    NASA Technical Reports Server (NTRS)

    Sevener, Kathleen M. (Inventor); Lohner, Kevin A. (Inventor); Mays, Jeffrey A. (Inventor); Wisner, Daniel L. (Inventor)

    2009-01-01

    A method for applying a mixed metal oxide catalyst to a metallic substrate for the creation of a robust, high temperature catalyst system for use in decomposing propellants, particularly hydrogen peroxide propellants, for use in propulsion systems. The method begins by forming a prepared substrate material consisting of a metallic inner substrate and a bound layer of a noble metal intermediate. Alternatively, a bound ceramic coating, or frit, may be introduced between the metallic inner substrate and noble metal intermediate when the metallic substrate is oxidation resistant. A high-activity catalyst slurry is applied to the surface of the prepared substrate and dried to remove the organic solvent. The catalyst layer is then heat treated to bind the catalyst layer to the surface. The bound catalyst layer is then activated using an activation treatment and calcinations to form the high-activity catalyst system.

  8. Computationally Probing the Performance of Hybrid, Heterogeneous, and Homogeneous Iridium-Based Catalysts for Water Oxidation

    SciTech Connect

    García-Melchor, Max; Vilella, Laia; López, Núria; Vojvodic, Aleksandra

    2016-04-29

    An attractive strategy to improve the performance of water oxidation catalysts would be to anchor a homogeneous molecular catalyst on a heterogeneous solid surface to create a hybrid catalyst. The idea of this combined system is to take advantage of the individual properties of each of the two catalyst components. We use Density Functional Theory to determine the stability and activity of a model hybrid water oxidation catalyst consisting of a dimeric Ir complex attached on the IrO2(110) surface through two oxygen atoms. We find that homogeneous catalysts can be bound to its matrix oxide without losing significant activity. Hence, designing hybrid systems that benefit from both the high tunability of activity of homogeneous catalysts and the stability of heterogeneous systems seems feasible.

  9. LaRC-developed catalysts for CO2 lasers

    NASA Technical Reports Server (NTRS)

    Upchurch, Billy T.; Kielin, Erik J.; Miller, Irvin M.

    1990-01-01

    Pulsed CO2 lasers have many remote sensing applications from space, airborne, and ground platforms. The NASA Laser Atmospheric Wind Sounder (LAWS) system will be designed to measure wind velocities from polar earth orbit for a period of up to three years. Accordingly, this and other applications require a closed-cycle pulsed CO2 laser which necessitates the use of an efficient CO-O2 recombination catalyst for these dissociation products which otherwise would degrade the laser operation. The required catalyst must not only operate at low temperatures but also must operate efficiently for long time periods. The research effort at NASA LaRC has centered around development and testing of CO oxidation catalysts for closed-cycle, pulsed, common and rare-isotope CO2 lasers. Researchers examined available commercial catalysts both in a laser and under simulated closed-cycle laser conditions with efforts aimed toward a thorough understanding of the fundamental catalytic reaction. These data were used to design and synthesize new catalyst compositions to better meet the catalyst requirements for closed-cycle pulsed CO2 lasers. Syntheses and test results for catalysts developed at Langley Research Center which have significantly better long-term decay characteristics than previously available catalysts and at the same time operate quite well under lower temperature conditions are discussed.

  10. Polymerization catalyst, production and use

    SciTech Connect

    Best, S.A.

    1987-01-06

    A process is described for the polymerization of ethylene and alpha-olefins having from 1 to 20 carbon atoms or mixtures of ethylene, alpha-olefins and diolefins. The process comprises polymerizing in the presence of a catalyst system comprising (a) an organo aluminum compound of the formula ALR''/sub n/X''/sub 3-n/ wherein R is hydrogen or a hydrocarbyl group having from 1 to 20 carbon atoms, X is halogen and is a number from 1 to 3, and (b) a transition metal containing catalyst component comprising the solid reaction product obtained by treating an inert solid support material in an inert solvent. This is done sequentially with (A) an organometallic compounds of a Group IIa, IIb or IIIa metal wherein all the metal valencies are satisfied with a hydrocarbon group, (B) an oxygen containing compound selected from ketones, aldehydes, alcohols or mixtures thereof, (C) an acyl halide, (D) at least one transition metal compound of a Group IVb, Vb, VIb or VIII metal, and (E) a group IIIa metal hydrocarbyl dihalide.

  11. Polymerization catalyst, production and use

    SciTech Connect

    Best, S.A.

    1987-01-06

    A process is described for the polymerization of ethylene and alpha-olefins having from 1 to 20 carbon atoms or mixtures of ethylene, alpha-olefins and diolefins. The process comprises polymerizing in the presence of a catalyst system comprising (a) an organo aluminum compound of the formula AIR''/sub n/X''/sub 3-n/ wherein R'' is hydrogen or a hydrocarbyl group having from 1 to 20 carbon atoms, X is halogen and n is a number from 1 to 3, and (B) a transition metal containing catalyst component comprising the solid reaction product obtained by treating an inert solid support material in an inert solvent. This is done sequentially with, optionally (A) Cl/sub 2/, Br/sub 2/, an interhalogen or mixtures thereof, (B) an organometallic compound of a Group IIa, IIb or IIIa metal wherein all the metal valencies are satisfied with a hydrocarbon group, (C) an oxygen containing compound selected from ketones, aldehydes, alcohols or mixtures thereof, (D) an acyl halide, (E) at least one transition metal compound of a Group IVb, VB, VIb or VIII metal, and (F) Cl/sub 2/, Br/sub 2/, an interhalogen or mixtures thereof.

  12. Polymerization catalyst, production and use

    SciTech Connect

    Best, S.A.

    1987-01-06

    A process is described for the polymerization of ethylene and alpha-olefins having from 1 to 20 carbon atoms or mixtures of ethylene, alpha-olefins and diolefins. The process comprises polymerizing in the presence of a catalyst system comprising (a) an organo aluminum compounds of the formula AIR''/sub n/X''/sub 3-n/ wherein R'' is hydrogen or a hydrocarbyl group having from 1 to 20 carbon atoms, X is halogen and n is a number from 1 to 3, and (b) a transition metal containing catalyst component comprising the solid reaction product obtained by treating an inert solid support material in an inert solvent. This is done sequentially with (A) an organometallic compound of a Group IIa, IIb, or IIIa metal wherein all the metal valencies are satisfied with a hydrocarbon group, optionally (B) an oxygen containing compound selected from ketones, aldehydes, alcohols, siloxanes or mixtures thereof, (C) at least one transition metal compound of a Group IVb, Vb, VIb or VIII metal, and (D) a group IIIa metal hydrocarbyl dihalide.

  13. SCALEUP OF ALUMINUM PHOSPHATE CATALYST FOR PILOT PLANT LPDMEtm RUN

    SciTech Connect

    Andrew W. Wang

    2002-05-15

    The Liquid Phase Dimethyl Ether (LPDME{trademark}) process converts synthesis gas to dimethyl ether in a single slurry bubble column reactor. A mixed slurry of methanol synthesis catalyst and methanol dehydration catalyst in a neutral mineral oil simultaneously synthesizes methanol from syngas and converts some of it to dimethyl ether and water. The reaction scheme is: 2H{sub 2} + CO = CH{sub 3}OH 2CH{sub 3}OH = CH{sub 3}OCH{sub 3} + H{sub 2}O H{sub 2}O + CO = CO{sub 2} + H{sub 2}. Most of the water produced in this reaction is converted to hydrogen by reduction with carbon monoxide (water gas shift reaction). This synergy permits higher per pass conversion than methanol synthesis alone. The enhancement in conversion occurs because dehydration of the methanol circumvents the equilibrium constraint of the syngas-to-methanol step. The slurry bubble column reactor provides the necessary heat transfer capacity to handle the greater heat duty associated with high conversion. In order to improve the stability of the catalyst system, non-stoichiometric aluminum phosphate was proposed as the dehydration catalyst for the LPDME{trademark} process. This aluminum phosphate material is a proprietary catalyst. This catalyst system of a standard methanol catalyst and the aluminum phosphate provided stable process performance that met the program targets under our standard test process conditions in the laboratory. These targets are (1) an initial methanol equivalent productivity of 28 gmol/kg/hr, (2) a CO{sub 2}-free, carbon selectivity of 80% to dimethyl ether and (3) stability of both catalysts equivalent to that of the methanol catalyst in the absence of the aluminum phosphate. A pilot plant trial of the LPDME{trademark} process using the aluminum phosphate catalyst was originally planned for March 1998 at the DOE-owned, Air Products (APCI)-operated facility at LaPorte, Texas. Because the aluminum phosphate catalyst is not commercially available, we initiated a scaleup project

  14. SCALEUP OF ALUMINUM PHOSPHATE CATALYST FOR PILOT PLANT LPDMEtm RUN

    SciTech Connect

    Andrew W. Wang

    2002-01-01

    The Liquid Phase Dimethyl Ether (LPDME{trademark}) process converts synthesis gas to dimethyl ether in a single slurry bubble column reactor. A mixed slurry of methanol synthesis catalyst and methanol dehydration catalyst in a neutral mineral oil simultaneously synthesizes methanol from syngas and converts some of it to dimethyl ether and water. The reaction scheme is shown below: 2H{sub 2} + CO = CH{sub 3}OH; 2CH{sub 3}OH = CH{sub 3}OCH{sub 3} + H{sub 2}O; H{sub 2}O + CO = CO{sub 2} + H{sub 2}. Most of the water produced in this reaction is converted to hydrogen by reduction with carbon monoxide (water gas shift reaction). This synergy permits higher per pass conversion than methanol synthesis alone. The enhancement in conversion occurs because dehydration of the methanol circumvents the equilibrium constraint of the syngas-to-methanol step. The slurry bubble column reactor provides the necessary heat transfer capacity to handle the greater heat duty associated with high conversion. In order to improve the stability of the catalyst system, non-stoichiometric aluminum phosphate was proposed as the dehydration catalyst for the LPDME{trademark} process. This aluminum phosphate material is a proprietary catalyst. This catalyst system of a standard methanol catalyst and the aluminum phosphate provided stable process performance that met the program targets under our standard test process conditions in the laboratory. These targets are (1) an initial methanol equivalent productivity of 28 gmol/kg/hr, (2) a CO{sub 2}-free, carbon selectivity of 80% to dimethyl ether and (3) stability of both catalysts equivalent to that of the methanol catalyst in the absence of the aluminum phosphate. A pilot plant trial of the LPDME{trademark} process using the aluminum phosphate catalyst was originally planned for March 1998 at the DOE-owned, Air Products (APCI)-operated facility at LaPorte, Texas. Because the aluminum phosphate catalyst is not commercially available, we initiated a

  15. Solid waste management of a chemical-looping combustion plant using Cu-based oxygen carriers.

    PubMed

    García-Labiano, Francisco; Gayán, Pilar; Adánez, Juan; De Diego, Luis F; Forero, Carmen R

    2007-08-15

    Waste management generated from a Chemical-Looping Combustion (CLC) plant using copper-based materials is analyzed by two ways: the recovery and recycling of the used material and the disposal of the waste. A copper recovery process coupled to the CLC plant is proposed to avoid the loss of active material generated by elutriation from the system. Solid residues obtained from a 10 kWth CLC prototype operated during 100 h with a CuO-Al2O3 oxygen carrier prepared by impregnation were used as raw material in the recovery process. Recovering efficiencies of approximately 80% were obtained in the process, where the final products were an eluate of Cu(NO3)2 and a solid. The eluate was used for preparation of new oxygen carriers by impregnation, which exhibited high reactivity for reduction and oxidation reactions as well as adequate physical and chemical properties to be used in a CLC plant. The proposed recovery process largely decreases the amount of natural resources (Cu and Al203) employed in a CLC power plant as well as the waste generated in the process. To determine the stability of the different solid streams during deposition in a landfill, these were characterized with respect to their leaching behavior according to the European Union normative. The solid residue finally obtained in the CLC plant coupled to the recovery process (composed by Al2O3 and CuAl2O4) can be classified as a stable nonreactive hazardous waste acceptable at landfills for nonhazardous wastes.

  16. Selective hydrogenolysis of glycerol to propylene glycol on Cu-ZnO composite catalysts: structural requirements and reaction mechanism.

    PubMed

    Wang, Shuai; Zhang, Yichi; Liu, Haichao

    2010-05-03

    Cu-ZnO catalysts were prepared by homogeneous coprecipitation with varying Cu/Zn atomic ratios (0.4-2:1). The catalysts were examined in selective hydrogenolysis of glycerol to propylene glycol. Although propylene glycol selectivities remained essentially constant (over 93%) on the different Cu-ZnO catalysts, the turnover frequencies changed markedly with the Cu/Zn ratio, and reached the greatest value at the ratio of 1:1. Such activity dependence on the Cu/Zn ratio was in parallel with the change in the interaction between Cu and ZnO and in the Cu microstrain, as a consequence of the effects on the crystalline phases of hydroxycarbonate precursors for the Cu-ZnO catalysts, reflecting the structural requirements for glycerol hydrogenolysis. The hydrogenolysis mechanism was also examined and apparently involves kinetically relevant glycerol dehydrogenation to glyceraldehyde on Cu-ZnO and subsequent glyceraldehyde dehydration and hydrogenation to propylene glycol. The mechanism is consistent with the observed superior activities of the more strained Cu particles, and the higher propylene glycol selectivities obtained at higher glycerol and hydrogen concentrations. These findings provide a rationale for the design of more effective Cu-based catalysts in selective hydrogenolysis of glycerol and other biomass-derived polyols, for example, by synthesis of highly strained Cu particles strongly interacting with ZnO or other oxide supports.

  17. Fluorination process using catalyst

    DOEpatents

    Hochel, Robert C.; Saturday, Kathy A.

    1985-01-01

    A process for converting an actinide compound selected from the group consisting of uranium oxides, plutonium oxides, uranium tetrafluorides, plutonium tetrafluorides and mixtures of said oxides and tetrafluorides, to the corresponding volatile actinide hexafluoride by fluorination with a stoichiometric excess of fluorine gas. The improvement involves conducting the fluorination of the plutonium compounds in the presence of a fluoride catalyst selected from the group consisting of CoF.sub.3, AgF.sub.2 and NiF.sub.2, whereby the fluorination is significantly enhanced. The improvement also involves conducting the fluorination of one of the uranium compounds in the presence of a fluoride catalyst selected from the group consisting of CoF.sub.3 and AgF.sub.2, whereby the fluorination is significantly enhanced.

  18. Fluorination process using catalysts

    DOEpatents

    Hochel, R.C.; Saturday, K.A.

    1983-08-25

    A process is given for converting an actinide compound selected from the group consisting of uranium oxides, plutonium oxides, uranium tetrafluorides, plutonium tetrafluorides and mixtures of said oxides and tetrafluorides, to the corresponding volatile actinide hexafluoride by fluorination with a stoichiometric excess of fluorine gas. The improvement involves conducting the fluorination of the plutonium compounds in the presence of a fluoride catalyst selected from the group consisting of CoF/sub 3/, AgF/sub 2/ and NiF/sub 2/, whereby the fluorination is significantly enhanced. The improvement also involves conducting the fluorination of one of the uranium compounds in the presence of a fluoride catalyst selected from the group consisting of CoF/sub 3/ and AgF/sub 2/, whereby the fluorination is significantly enhanced.

  19. Binary ferrihydrite catalysts

    DOEpatents

    Huffman, G.P.; Zhao, J.; Feng, Z.

    1996-12-03

    A method of preparing a catalyst precursor comprises dissolving an iron salt and a salt of an oxoanion forming agent, in water so that a solution of the iron salt and oxoanion forming agent salt has a ratio of oxoanion/Fe of between 0.0001:1 to 0.5:1. Next is increasing the pH of the solution to 10 by adding a strong base followed by collecting of precipitate having a binary ferrihydrite structure. A binary ferrihydrite catalyst precursor is also prepared by dissolving an iron salt in water. The solution is brought to a pH of substantially 10 to obtain ferrihydrite precipitate. The precipitate is then filtered and washed with distilled water and subsequently admixed with a hydroxy carboxylic acid solution. The admixture is mixed/agitated and the binary ferrihydrite precipitate is then filtered and recovered. 3 figs.

  20. Binary ferrihydrite catalysts

    DOEpatents

    Huffman, Gerald P.; Zhao, Jianmin; Feng, Zhen

    1996-01-01

    A method of preparing a catalyst precursor comprises dissolving an iron salt and a salt of an oxoanion forming agent, in water so that a solution of the iron salt and oxoanion forming agent salt has a ratio of oxoanion/Fe of between 0.0001:1 to 0.5:1. Next is increasing the pH of the solution to 10 by adding a strong base followed by collecting of precipitate having a binary ferrihydrite structure. A binary ferrihydrite catalyst precursor is also prepared by dissolving an iron salt in water. The solution is brought to a pH of substantially 10 to obtain ferrihydrite precipitate. The precipitate is then filtered and washed with distilled water and subsequently admixed with a hydroxy carboxylic acid solution. The admixture is mixed/agitated and the binary ferrihydrite precipitate is then filtered and recovered.

  1. External Catalyst Breakup Phenomena

    DTIC Science & Technology

    1976-06-01

    anhydrous amonia cylinder and associated valve is revealed in the background. Nominal instrumentation for the reactor tests consisted of Temperatures...above the catalyst bed. Liquid, anhydrous ammonia was selected as the quench medium after consideration of the influence water might have on...corresponding to this G Iading and temperature at an amonia dissociation fraction of 0.5 and Lhamber pressure of 200 psia is 18.4 ft/sec. A typical five pound

  2. Steam reforming catalyst

    DOEpatents

    Kramarz, Kurt W.; Bloom, Ira D.; Kumar, Romesh; Ahmed, Shabbir; Wilkenhoener, Rolf; Krumpelt, Michael

    2001-01-01

    A method of forming a hydrogen rich gas from a source of hydrocarbon fuel. A vapor of the hydrocarbon fuel and steam is brought in contact with a two-part catalyst having a dehydrogenation powder portion and an oxide-ion conducting powder portion at a temperature not less than about 770.degree.C. for a time sufficient to generate the hydrogen rich. The H.sub.2 content of the hydrogen gas is greater than about 70 percent by volume. The dehydrogenation portion of the catalyst includes a group VIII metal, and the oxide-ion conducting portion is selected from a ceramic oxide from the group crystallizing in the fluorite or perovskite structure and mixtures thereof. The oxide-ion conducting portion of the catalyst is a ceramic powder of one or more of ZrO.sub.2, CeO.sub.2, Bi.sub.2 O.sub.3, (BiVO).sub.4, and LaGaO.sub.3.

  3. Guanidinium groups act as general-acid catalysts in phosphoryl transfer reactions: a two-proton inventory on a model system.

    PubMed

    Piatek, Anna M; Gray, Mark; Anslyn, Eric V

    2004-08-18

    Cleavage/transesterification of phosphodiesters is catalyzed by various acidic groups in solution and with enzymes. General-acid catalysts can transfer protons to the developing phosphorane intermediate, resulting in a monoprotic-monoanionic intermediate, giving the so-called "triester mechanism". Using a proton inventory on a model compound (1) possessing an intramolecular hydrogen bond between a phosphodiester and a guanidinium group, we find that two protons move in the rate-determining step for cleavage/transesterification. In contrast, HPNP shows a single-proton inventory and is a substrate well accepted to react with the movement of only one proton at the transition state. We therefore propose a mechanism for 1 that involves general-acid catalysis by the guanidinium group. This leads one to conclude that other, more acidic groups, such as ammonium and imidazolium, would also act as general-acid catalysts.

  4. New pyridinium-based ionic liquid as an excellent solvent-catalyst system for the one-pot three-component synthesis of 2,3-disubstituted quinolines.

    PubMed

    Anvar, Salma; Mohammadpoor-Baltork, Iraj; Tangestaninejad, Shahram; Moghadam, Majid; Mirkhani, Valiollah; Khosropour, Ahmad Reza; Landarani Isfahani, Amir; Kia, Reza

    2014-03-10

    The synthesis of a variety of 2,3-disubstituted quinolines has been achieved successfully via a one-pot three-component reaction of arylamines, arylaldehydes and aliphatic aldehydes in the presence of butylpyridinium tetrachloroindate(III), [bpy][InCl4], ionic liquid as a green catalyst and solvent. Mild conditions with excellent conversions, and simple product isolation procedure are noteworthy advantages of this method. The recyclability of the ionic liquid makes this protocol environmentally benign.

  5. Structure and function of real catalysts

    NASA Astrophysics Data System (ADS)

    Klier, K.

    1984-11-01

    This paper addresses issues such as the relation between the physical and chemical nature of active centers, activation of reactant molecules, mechanisms of catalytic reactions and distribution of promoters in real catalysts which are invariably multicomponent multiphase systems. Interactions among the catalyst components and phases often result in the formation of compounds and defects that do not exist in the separate components. Although such interactions give rise to a great variety of morphologic, chemical, and electronic properties of the real catalysts, they can be controlled, mostly by careful preparation and doping procedures, to the degree that the catalyst displays reproducible activity and selectivity. Most of the examples given in this paper are based on the results from the author's laboratory concerning the activity and selectivity of copper-based catalysts for the hydrogenation of carbon monoxide and carbon dioxide, the water gas shift reaction, and some reactions of amines. Evidence is presented for the interactions between the copper and zinc oxide then analyzed in terms of defect equilibria using models and constants partially known from the literature and adapted for the present system. It is shown on the basis of boundary layer theory for small particles that charge transfer between copper metal particles, also present in the system, and the zinc oxide phase is insignificant. On the other hand, electron equilibria between the solute copper species and the zinc oxide matrix are dictated primarily by intrinsic ionization Cu 0 → Cu + + e - and oxygen vacancy formation. Optical absorption spectroscopy strongly corroborates the theoretical contention that a significant portion of the copper is in electron deficient state, and there is some evidence based on Auger spectroscopy for the presence of Cu + species on the catalyst surface. It is reiterated, as has been proposed before in our earlier work, that these copper species activate substrates

  6. Nitrogen enriched mesoporous organic polymer anchored copper(II) material: an efficient and reusable catalyst for the synthesis of esters and amides from aromatic systems.

    PubMed

    Molla, Rostam Ali; Iqubal, Md Asif; Ghosh, Kajari; Kamaluddin; Islam, Sk Manirul

    2015-04-14

    A new copper-grafted mesoporous poly-melamine-formaldehyde (Cu-mPMF) has been synthesized from melamine and paraformaldehyde in DMSO medium, followed by grafting of Cu(ii) at its surface. Cu-mPMF has been characterized by elemental analysis, powder XRD, HR TEM, FE-SEM, N2 adsorption study, FT-IR, UV-vis DRS, TGA-DTA, EPR spectroscopy, Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). The Cu-grafted mesoporous material showed very good catalytic activity in methyl esterification of benzylic alcohols and amidation of nitriles. Moreover, the catalyst is easily recoverable and can be reused seven times without appreciable loss of catalytic activity in the above reactions. The highly dispersed and strongly bound Cu(ii) sites in the Cu-grafted mesoporous polymer could be responsible for the observed high activities of the Cu-mPMF catalyst. Due to strong binding with the functional groups of the polymer, no evidence of leached copper from the catalyst during the course of reaction emerged, suggesting true heterogeneity in the catalytic process.

  7. Removal of Disinfection By-Products from Contaminated Water Using a Synthetic Goethite Catalyst via Catalytic Ozonation and a Biofiltration System·

    PubMed Central

    Wang, Yu-Hsiang; Chen, Kuan-Chung

    2014-01-01

    The effects of synthetic goethite (α-FeOOH) used as the catalyst in catalytic ozonation for the degradation of disinfection by-product (DBP) precursors are investigated. A biofiltration column applied following the catalytic ozonation process is used to evaluate the efficiency of removing DBP precursors via biotreatment. Ozone can rapidly react with aromatic compounds and oxidize organic compounds, resulting in a decrease in the fluorescence intensity of dissolved organic matter (DOM). In addition, catalytic ozonation can break down large organic molecules, which causes a blue shift in the emission-excitation matrix spectra. Water treated with catalytic ozonation is composed of low-molecular structures, including soluble microbial products (SMPs) and other aromatic proteins (APs). The DOM in SMPs and APs is removed by subsequent biofiltration. Catalytic ozonation has a higher removal efficiency for dissolved organic carbon and higher ultraviolet absorbance at 254 nm compared to those of ozonation without a catalyst. The use of catalytic ozonation and subsequent biofiltration leads to a lower DBP formation potential during chlorination compared to that obtained using ozonation and catalytic ozonation alone. Regarding DBP species during chlorination, the bromine incorporation factor (BIF) of trihalomethanes and haloacetic acids increases with increasing catalyst dosage in catalytic ozonation. Moreover, the highest BIF is obtained for catalytic ozonation and subsequent biofiltration. PMID:25211774

  8. Characterization and reactivity of nanoscale La(Co,Cu)O 3 perovskite catalyst precursors for CO hydrogenation

    NASA Astrophysics Data System (ADS)

    Tien-Thao, Nguyen; Alamdari, Houshang; Kaliaguine, Serge

    2008-08-01

    The characterization of La(Co,Cu)O 3 perovskites has been performed by several techniques including XRD, BET, H 2-TPR, O 2-TPO, TPRS, and the solids tested as catalysts for the hydrogenation of CO. The reducibility of the perovskites is strongly affected by the preparation route, calcination temperature, catalyst morphology, and the amount of remnant alkali. Compared with the citrate-derived perovskite, LaCoO 3 sample prepared by mechano-synthesis has various distinct Co 3+ ions in perovskite lattice, which are reduced at different temperatures. Under typical conditions, the reduction of cobalt ions occurs in two consecutive steps: Co 3+/Co 2+ and Co 2+/Co 0, while the intra-lattice copper ions are directly reduced from Cu 2+ to Cu 0. The reducibility of cobalt ions is promoted by the presence of metallic copper, which is formed at a lower reduction temperature. The re-oxidation of the reduced lanthanum cobaltite perovskite could regenerate the original structure, whereas that of the reduced Co-Cu-based samples is less reversible under the same experimental conditions. The cobalt atom in the reduced perovskites plays an important role in the dissociation of CO, but the presence of a neighboring copper along with remnant sodium ions on the catalyst surface has remarkably affected the reactivity of cobalt for CO hydrogenation. The addition of copper into the perovskite framework leads to a change in the product distribution of CO hydrogenation and a decrease in reaction temperature. An increased copper content leads to a substantial decline in the rate of methanation and an increase in the formation of higher alcohols. A close proximity between cobalt and copper sites on the Na +-modified catalyst surface of the reduced nanocrystalline Co-Cu-based perovskites plays a crucial role in the synthesis of higher alcohols from syngas.

  9. Decoupling HZSM-5 catalyst activity from deactivation during upgrading of pyrolysis oil vapors.

    PubMed

    Wan, Shaolong; Waters, Christopher; Stevens, Adam; Gumidyala, Abhishek; Jentoft, Rolf; Lobban, Lance; Resasco, Daniel; Mallinson, Richard; Crossley, Steven

    2015-02-01

    The independent evaluation of catalyst activity and stability during the catalytic pyrolysis of biomass is challenging because of the nature of the reaction system and rapid catalyst deactivation that force the use of excess catalyst. In this contribution we use a modified pyroprobe system in which pulses of pyrolysis vapors are converted over a series of HZSM-5 catalysts in a separate fixed-bed reactor controlled independently. Both the reactor-bed temperature and the Si/Al ratio of the zeolite are varied to evaluate catalyst activity and deactivation rates independently both on a constant surface area and constant acid site basis. Results show that there is an optimum catalyst-bed temperature for the production of aromatics, above which the production of light gases increases and that of aromatics decrease. Zeolites with lower Si/Al ratios give comparable initial rates for aromatics production, but far more rapid catalyst deactivation rates than those with higher Si/Al ratios.

  10. Catalyst Additives to Enhance Mercury Oxidation and Capture

    SciTech Connect

    Alex J. Berry; Thomas K. Gale

    2005-09-30

    Preliminary research has shown that SCR catalysts employed for nitrogen-oxide reduction can effectively oxidize mercury. This report discusses initial results from fundamental investigations into the behavior of mercury species in the presence of SCR catalysts at Southern Research Institute. The testing was performed at Southern Research's Catalyst Test Facility, a bench-scale reactor capable of simulating gas-phase reactions occurring in coal-fired utility pollution-control equipment. Three different SCR catalysts are currently being studied in this project - honeycomb-type, plate-type, and a hybrid-type catalyst. The catalysts were manufactured and supplied by Cormetech Inc., Hitachi America Ltd., and Haldor-Topsoe Inc., respectively. Parametric testing was performed to investigate the contribution of flue-gas chemistry on mercury oxidation via SCR catalysts. Methods and procedures for experimental testing continue to be developed to produce the highest quality mercury-oxidation data. Most experiments so far have focused on testing the catalysts in a simulated Powder River Basin (PRB) flue-gas environment, which contains lower sulfur and chlorine than produced by other coals. Future work to characterize flue gas simulations typically derived from low and high sulfur bituminous coal will be performed in a stepwise manner, to avoid the constant interruptions in testing that occur when leaks in the system are generated during temperature transitions. Specifically, chlorine concentration vs. mercury oxidation graph will be developed for each catalyst. The contributions of temperature and later sulfur will be investigated after this is complete. Also, last quarter's tests showed a potential linear relationship between SO3 conversion and mercury oxidation. As a result, SO3 samples will be taken more frequently to investigate each catalyst's ability to selectively oxidize mercury.

  11. Scoping economics for the commercial manufacture of metallocene catalysts

    SciTech Connect

    Brockmeier, N.F.

    1994-05-26

    This study assumes that commercial-scale production of propylene-based isotactic polymers with metallocene catalyst systems will become a reality. The challenge that must be overcome for commercial success with these propylene polymers is to discover a metallocene system recipe that will give sufficient catalyst activity along with the requisite stereo-selectivity at reasonable cost. Anticipating such a discovery, it is assumed here that the economics are well-represented by a catalyst system that consists in part of a silylene-bridged cyclopentadienyl zirconocene made in a batchwise process having an annual capacity of 15,000 pounds. Activation will be achieved with a cocatalyst such as methylaluminoxane (MAO), coated in conjunction with the catalyst on a support such as silica. The MAO at an estimated $100/lb contributes $1800/lb cost to the finished catalyst with an assumed recipe of 18:1 mass ratio of MAO to zirconocene. Based on a 20% return on investment, the selling price for the supported zirconocene system is estimated to be $2915/lb. The required capital investment to make 735,000 lb/yr of the total supported system is 9 million dollars. These estimates have {plus_minus}50% range of uncertainty. Payback period for this plant in a sold-out condition is three years. The catalyst system cost in ethylene-propylene copolymer is 3.9 cents per pound with a productivity of 75,000 lb polymer/lb of zirconocene. An Appendix includes some economic details.

  12. Dispersion enhanced metal/zeolite catalysts

    DOEpatents

    Sachtler, W.M.H.; Tzou, M.S.; Jiang, H.J.

    1987-03-31

    Dispersion stabilized zeolite supported metal catalysts are provided as bimetallic catalyst combinations. The catalyst metal is in a reduced zero valent form while the dispersion stabilizer metal is in an unreduced ionic form. Representative catalysts are prepared from platinum or nickel as the catalyst metal and iron or chromium dispersion stabilizer.

  13. Dispersion enhanced metal/zeolite catalysts

    DOEpatents

    Sachtler, Wolfgang M. H.; Tzou, Ming-Shin; Jiang, Hui-Jong

    1987-01-01

    Dispersion stabilized zeolite supported metal catalysts are provided as bimetallic catalyst combinations. The catalyst metal is in a reduced zero valent form while the dispersion stabilizer metal is in an unreduced ionic form. Representative catalysts are prepared from platinum or nickel as the catalyst metal and iron or chromium dispersion stabilizer.

  14. Novel Intermetallic Catalysts to Enhance PEM Membrane Durability

    SciTech Connect

    Francis J. DiSalvo

    2009-01-06

    The research examined possible sources of degradation of platinum based anode catalysts under long term use. Scientists at the United Technologies Research Center had shown that the anode as well as the cathode catalysts degrade in hydrogen fuel cells. This goal of this research was to see if mechanisms of anode degradation could be understood using forefront electrochemical techniques in an aqueous system. We found that this method is limited by the very low levels of impurities (perhaps less than a part per trillion) in the electrolyte. This limitation comes from the relatively small catalyst surface area (a few sq cm or less) compared to the electrolyte volume of 10 to 25 ml. In real fuel cells this ratio is completelyreversed: high catalyst surface area and low electrolyte violume, making the system much less sensitive to impurities in the electrolyte. We conclude that degradation mechanisms should be studied in real fuel cell systems, rather than in ex-situ, large electrolyte volume experiments.

  15. Routes for deactivation of different autothermal reforming catalysts

    NASA Astrophysics Data System (ADS)

    Pasel, Joachim; Wohlrab, Sebastian; Kreft, Stefanie; Rotov, Mikhail; Löhken, Katrin; Peters, Ralf; Stolten, Detlef

    2016-09-01

    Fuel cell systems with integrated autothermal reforming units require active and robust catalysts for H2 production. In pursuit of this, an experimental screening of catalysts utilized in the autothermal reforming of commercial diesel fuels is performed. The catalysts incorporate a monolithic cordierite substrate, an oxide support (γ-Al2O3, La-Al2O3, CeO2, Gd-CeO2, ZrO2, Y-ZrO2) and Rh as the active phase. Experiments are run by widely varying the O2/C and H2O/C molar ratios at different gas hourly space velocities. In most cases, this provokes accelerated catalyst deactivation and permits an informative comparison of the catalysts. Fresh and aged catalysts are characterized by temperature-programmed methods, thermogravimetry and transmission electron microscopy to find correlations with catalytic activity and stability. Using this approach, routes for catalyst deactivation are identified, together with causes of different catalytic activities. Suitable reaction conditions can be derived from our results for the operation of reactors for autothermal reforming at steady-state and under transient reaction conditions, which helps improve the efficiency and the stability of fuel cell systems.

  16. Oxygen-reducing catalyst layer

    DOEpatents

    O'Brien, Dennis P [Maplewood, MN; Schmoeckel, Alison K [Stillwater, MN; Vernstrom, George D [Cottage Grove, MN; Atanasoski, Radoslav [Edina, MN; Wood, Thomas E [Stillwater, MN; Yang, Ruizhi [Halifax, CA; Easton, E Bradley [Halifax, CA; Dahn, Jeffrey R [Hubley, CA; O'Neill, David G [Lake Elmo, MN

    2011-03-22

    An oxygen-reducing catalyst layer, and a method of making the oxygen-reducing catalyst layer, where the oxygen-reducing catalyst layer includes a catalytic material film disposed on a substrate with the use of physical vapor deposition and thermal treatment. The catalytic material film includes a transition metal that is substantially free of platinum. At least one of the physical vapor deposition and the thermal treatment is performed in a processing environment comprising a nitrogen-containing gas.

  17. Development of GREET Catalyst Module

    SciTech Connect

    Wang, Zhichao; Benavides, Pahola T.; Dunn, Jennifer B.; Cronauer, Donald C.

    2015-09-01

    In this report, we develop energy and material flows for the production of five different catalysts (tar reforming, alcohol synthesis, Zeolite Socony Mobil-5 [ZSM-5], Mo/Co/ γ-Al2O3, and Pt/ γ-Al2O3) and two chemicals (olivine, dimethyl ether of polyethylene glycol [DEPG]). These compounds and catalysts are now included in the Greenhouse Gases, Regulated Emissions and Energy Use in Transportation (GREET™) catalyst module.

  18. Mixed Alcohol Synthesis Catalyst Screening 2007 Progress Report

    SciTech Connect

    Gerber, Mark A.; White, J. F.; Gray, Michel J.; Stevens, Don J.

    2007-11-01

    Pacific Northwest National Laboratory (PNNL) and National Renewable Energy Laboratory (NREL) are researching the feasibility of producing mixed alcohols from biomass-derived synthesis gas (syngas). PNNL is obtaining commercially available mixed alcohol or preparing promising mixed-alcohol catalysts and screening them in a laboratory-scale reactor system. The most promising catalysts are provided to NREL for testing using a slipstream from a pilot-scale biomass gasifier. After a review of the literature in 2006 and conversations with companies that produce catalysts, it was determined that no commercial mixed-alcohol synthesis catalysts were available. One manufacturer supplied a modified methanol catalyst that was tested in the PNNL laboratory-scale system and provided to NREL for further testing. PNNL also prepared and tested the behavior of 10 other catalysts representing the distinct catalyst classes for mixed alcohol syntheses. Based on those results,testing in 2007 focused on the performance of the rhodium-based catalysts. The effects of adding promoters to the rhodium catalysts in addition to the manganese already being used were examined. The iron and rhenium promoters both stood out as achieving higher carbon selectivities , followed by Cu. Iridium and Li, on the other hand, had low carbon selectivity ratios of 0.27 and 0.22, respectively. Although testing of candidate promoters is not complete, it appears that Ir and Li promoters warrant further optimization and possibly combination to further improve STYs and carbon selectivities to C2+ oxygenates. However, using these promoters, it will be necessary to incorporate a separate hydrogenation catalyst to improve the yield of C2+ alcohols with respect to the other oxygenates. Fe, Re, and Cu stand out as possible candidates in this respect, but additional research is needed to examine whether they can be combined with the other promoters on the Rh-based catalyst or need to be optimized on a separate catalyst

  19. Catalyst for producing lower alcohols

    DOEpatents

    Rathke, Jerome W.; Klingler, Robert J.; Heiberger, John J.

    1987-01-01

    A process and system for the production of the lower alcohols such as methanol, ethanol and propanol involves the reaction of carbon monoxide and water in the presence of a lead salt and an alkali metal formate catalyst combination. The lead salt is present as solid particles such as lead titanate, lead molybdate, lead vanadate, lead zirconate, lead tantalate and lead silicates coated or in slurry within molten alkali metal formate. The reactants, carbon monoxide and steam are provided in gas form at relatively low pressures below 100 atmospheres and at temperatures of 200-400.degree. C. The resulted lower alcohols can be separated into boiling point fractions and recovered from the excess reactants by distillation.

  20. Results of catalyst testing using iron-based catalysts

    SciTech Connect

    Linehan, J.C.; Darab, J.G.; Matson, D.W.

    1993-03-01

    As coal liquefaction catalysts, iron-based products are generally inferior to the more expensive molybdenum, cobalt, or nickel-based materials. However, the lower costs of production and recovery (or in the case of some iron catalysts, non-recovery) give the iron-based materials a potential economic advantage over the more efficient precious and semi-precious metal catalysts for this application. Recent research has shown that a number of different iron-containing materials can be successfully utilized as coal liquefaction catalysts or as catalyst. Pyrrhotite (Fe[sub 1-x]S) or a similar iron-sulfide phase is commonly believed to be the active catalyst in coal liquefaction and model compound pyrolysis reactions, although no specific phase has been yet been isolated as the actual catalyst species. The active iron-containing catalyst is usually generated in situ from an iron-oxide precursor and an elemental sulfur source under reducing conditions in the reactor vessel. Most research has concentrated on the use of common iron-oxide phases such as hematite or goethite (and their derivatives) as the iron-bearing precursor, or on non-specific iron materials produced by the reaction of various iron salts and compounds in the coal or liquefaction reactor. To our knowledge there has been no systematic effort to determine the optimum iron-containing precursor phase for producing active coal liquefaction catalysts, despite the fact that there are over ten iron-(hydroxy)oxide phases which can be easily synthesized in the laboratory. We have undertaken a systematic study to identify the most active iron-oxide catalyst precursor phases, the co-catalysts, and the coal pretreatments which will provide optimum yields in coal liquefaction processes.

  1. Nano Catalysts for Diesel Engine Emission Remediation

    SciTech Connect

    Narula, Chaitanya Kumar; Yang, Xiaofan; Debusk, Melanie Moses; Mullins, David R; Mahurin, Shannon Mark; Wu, Zili

    2012-06-01

    conditions were provided by our collaborators at John Deere Power Systems. Among various zeolites reported here, CuFe-SSZ-13 offers the best NO{sub x} conversion activity in 150-650 C range and is hydrothermally stable when tested under accelerated aging conditions. It is important to note that Cu-SSZ-13 is now a commercial catalyst for NO{sub x} treatment on diesel passenger vehicles. Thus, our catalyst performs better than the commercial catalyst under fast SCR conditions. We initially focused on fast SCR tests to enable us to screen catalysts rapidly. Only the catalysts that exhibit high NO{sub x} conversion at low temperatures are selected for screening under varying NO{sub 2}:NO{sub x} ratio. The detailed tests of CuFe-SSZ-13 show that CuFe-SSZ-13 is more effective than commercial Cu-SSZ-13 even at NO{sub 2}:NO{sub x} ratio of 0.1. The mechanistic studies, employing stop-flow diffuse reflectance FTIR spectroscopy (DRIFTS), suggest that high concentration of NO{sup +}, generated by heterobimetallic zeolites, is probably responsible for their superior low temperature NO{sub x} activity. The results described in this report clearly show that we have successfully completed the first step in a new emission treatment catalyst which is synthesis and laboratory testing employing simulated exhaust. The next step in the catalyst development is engine testing. Efforts are in progress to obtain follow-on funding to carry out scale-up and engine testing to facilitate commercialization of this technology.

  2. Influence of nano-Al2O3-reinforced oxide-dispersion-strengthened Cu on the mechanical and tribological properties of Cu-based composites

    NASA Astrophysics Data System (ADS)

    Zhao, Xiang; Guo, Lei-chen; Zhang, Long; Jia, Ting-ting; Chen, Cun-guang; Hao, Jun-jie; Shao, Hui-ping; Guo, Zhi-meng; Luo, Ji; Sun, Jun-bin

    2016-12-01

    The mechanical and tribological properties of Cu-based powder metallurgy (P/M) friction composites containing 10wt%-50wt% oxide-dispersion-strengthened (ODS) Cu reinforced with nano-Al2O3 were investigated. Additionally, the friction and wear behaviors as well as the wear mechanism of the Cu-based composites were characterized by scanning electron microscopy (SEM) in conjunction with energy-dispersive X-ray spectroscopy (EDS) elemental mapping. The results indicated that the Cu-based friction composite containing 30wt% ODS Cu exhibited the highest hardness and shear strength. The average and instantaneous friction coefficient curves of this sample, when operated in a high-speed train at a speed of 300 km/h, were similar to those of a commercial disc brake pad produced by Knorr-Bremse AG (Germany). Additionally, the lowest linear wear loss of the obtained samples was (0.008 ± 0.001) mm per time per face, which is much lower than that of the Knorr-Bremse pad ((0.01 ± 0.001) mm). The excellent performance of the developed pad is a consequence of the formation of a dense oxide composite layer and its close combination with the pad body.

  3. Extended Catalyst Longevity Via Supercritical Isobutane Regeneration of a Partially Deactivated USY Alkylation Catalyst

    SciTech Connect

    Daniel M. Ginosar; David N. Thompson; Kyle C. Burch; David J. Zalewski

    2005-05-01

    Off-line, in situ activity recovery of a partially deactivated USY zeolite catalyst used for isobutane/butene alkylation was examined in a continuous-flow reaction system employing supercritical isobutane. Catalyst samples were deactivated in a controlled manner by running them to either to a fixed butene conversion level of 95% or a fixed time on stream of three hours, and then exposing the catalyst to supercritical isobutane to restore activity. Activity recovery was determined by comparing alkylation activity before and after the regeneration step. Both single and multiple regenerations were performed. Use of a 95% butene conversion level criterion to terminate the reaction step afforded 86% activity recovery for a single regeneration and provided nine sequential reaction steps for the multiple regeneration studies. Employing a fixed 3 h time on stream criterion resulted in nearly complete activity recovery for a single regeneration, and 24 reaction steps were demonstrated in sequence for the multiple regeneration process, producing only minor product yield declines per step. This resulted in a 12-fold increase in catalyst longevity versus unregenerated catalyst.

  4. Use of ionic liquids as coordination ligands for organometallic catalysts

    DOEpatents

    Li, Zaiwei; Tang, Yongchun; Cheng; Jihong

    2009-11-10

    Aspects of the present invention relate to compositions and methods for the use of ionic liquids with dissolved metal compounds as catalysts for a variety of chemical reactions. Ionic liquids are salts that generally are liquids at room temperature, and are capable of dissolving a many types of compounds that are relatively insoluble in aqueous or organic solvent systems. Specifically, ionic liquids may dissolve metal compounds to produce homogeneous and heterogeneous organometallic catalysts. One industrially-important chemical reaction that may be catalyzed by metal-containing ionic liquid catalysts is the conversion of methane to methanol.

  5. DEHYDROGENATION CATALYST FOR PRODUCTION OF MTBE

    EPA Science Inventory

    The objectives of this project were to better understand the effect of different catalyst preparation parameters, the effect of different catalyst treatment parameters, and the mechanism of deactivation. Accordingly, catalysts were made using various preparation methods and with...

  6. Molecular water oxidation catalyst

    DOEpatents

    Gratzel, Michael; Munavalli, Shekhar; Pern, Fu-Jann; Frank, Arthur J.

    1993-01-01

    A dimeric composition of the formula: ##STR1## wherein L', L", L'", and L"" are each a bidentate ligand having at least one functional substituent, the ligand selected from bipyridine, phenanthroline, 2-phenylpyridine, bipyrimidine, and bipyrazyl and the functional substituent selected from carboxylic acid, ester, amide, halogenide, anhydride, acyl ketone, alkyl ketone, acid chloride, sulfonic acid, phosphonic acid, and nitro and nitroso groups. An electrochemical oxidation process for the production of the above functionally substituted bidentate ligand diaqua oxo-bridged ruthenium dimers and their use as water oxidation catalysts is described.

  7. Novel Reforming Catalysts

    SciTech Connect

    Pfefferle, Lisa D; Haller, Gary L

    2012-10-16

    Aqueous phase reforming is useful for processing oxygenated hydrocarbons to hydrogen and other more useful products. Current processing is hampered by the fact that oxide based catalysts are not stable under high temperature hydrothermal conditions. Silica in the form of structured MCM-41 is thermally a more stable support for Co and Ni than conventional high surface area amorphous silica but hydrothermal stability is not demonstrated. Carbon nanotube supports, in contrast, are highly stable under hydrothermal reaction conditions. In this project we show that carbon nanotubes are stable high activity/selectivity supports for the conversion of ethylene glycol to hydrogen.

  8. Tandem hydroformylation/hydrogenation of alkenes to normal alcohols using Rh/Ru dual catalyst or Ru single component catalyst.

    PubMed

    Takahashi, Kohei; Yamashita, Makoto; Nozaki, Kyoko

    2012-11-14

    The catalyst system for tandem hydroformylation/hydrogenation of terminal alkenes to the corresponding homologated normal alcohol was developed. The reaction mechanism for the Rh/Ru dual catalyst was investigated by real-time IR monitoring experiments and (31)P NMR spectroscopy, which proved the mutual orthogonality of Rh-catalyzed hydroformylation and Ru-catalyzed hydrogenation. Detailed investigation about Ru-catalyzed hydrogenation of undecanal under H(2)/CO pressure clarified different kinetics from the hydrogenation under H(2) and gave a clue to design more active hydrogenation catalysts under H(2)/CO atmosphere. The solely Ru-catalyzed normal selective hydroformylation/hydrogenation is also reported.

  9. Ultrasound-assisted phase-transfer catalysis: benzoylation of sodium 4-acetylphenoxide by dual-site phase-transfer catalyst in a tri-liquid system.

    PubMed

    Yang, Hung-Ming; Chiu, Chun-Cheng

    2011-01-01

    A novel dual-site phase-transfer catalyst (PTC) was prepared and used to conduct the benzoylation of sodium 4-acetylphenoxide by ultrasound-assisted third-liquid phase-transfer catalysis. The catalyst 1,4-bis(tributylammoniomethyl)benzene dibromide (BTBAMBB) was synthesized from the reaction of p-xylylene dibromide and tributylamine in toluene at 70°C. The dual-site PTC was employed to form the third-liquid phase by extra addition of 0.04-0.05 mol of NaCl into 10 cm(3) of water. In the condition of 0.0425 mol of NaCl at 30°C, the catalytic intermediate in the third-liquid phase reached a maximum value. Almost 80% of the catalyst was transferred from the aqueous phase into the third-liquid phase. The distributions of the catalytic intermediate and dual-site PTC between phases and the kinetics of benzoylation of sodium 4-acetylphenoxide catalyzed by BTBAMBB with ultrasound irradiation were performed. The pseudo-first-order kinetic equation was applied to describe the overall reaction. Under ultrasound irradiation (28 kHz/300 W) in a batch reactor, the yield of product 4-acetylphenyl benzoate in the organic phase was 98.1% in 2 min at 30°C and 250 rpm with the apparent rate constant k(app) to be 0.0075 s(-1), which was 6 times faster than that without using ultrasound (yield=14.4%, k(app)=0.0013 s(-1)). The present study provides a green method to synthesize esters by ultrasound-assisted third-liquid phase-transfer catalysis.

  10. Aqueous phase reforming of glycerol over Ni-based catalysts for hydrogen production.

    PubMed

    Cho, Su Hyun; Moon, Dong Ju

    2011-08-01

    Aqueous phase reforming of glycerol over Ni-based catalysts for hydrogen production was carried out at 225 degrees C, 23 bar and LHSV = 4 h(-1). The Ni-based catalyst was prepared by an incipient wetness impregnation method. The catalysts before and after the reaction were characterized by N2 physisorption, CO chemisorption, XRD, TPR, SEM and TEM techniques. It was found that Ni(20 wt%)-Co(3 wt%)/gamma-Al2O3 catalyst showed higher glycerol conversion and hydrogen selectivity than Ni(20 wt%)/gamma-Al2O3 catalyst. There are no major changes in Ni particles after the reaction over Ni-Co/gamma-Al2O3 catalyst. The results suggest that the Ni-Co/gamma-Al2O3 catalyst can be applied to the hydrogen production system using APR of glycerol.

  11. Cyclic alkyl amino carbene (CAAC) ruthenium complexes as remarkably active catalysts for ethenolysis

    SciTech Connect

    Marx, Vanessa M.; Sullivan, Alexandra H.; Melaimi, Mohand; Virgil, Scott C.; Keitz, Benjamin K.; Weinberger, David S.; Bertrand, Guy; Grubbs, Robert H.

    2014-12-17

    In this paper, an expanded family of ruthenium-based metathesis catalysts bearing cyclic alkyl amino carbene (CAAC) ligands was prepared. These catalysts exhibited exceptional activity in the ethenolysis of the seed-oil derivative methyl oleate. In many cases, catalyst turnover numbers (TONs) of more than 100,000 were achieved, at a catalyst loading of only 3 ppm. Remarkably, the most active catalyst system was able to achieve a TON of 340 000, at a catalyst loading of only 1 ppm. Finally, this is the first time a series of metathesis catalysts has exhibited such high performance in cross-metathesis reactions employing ethylene gas, with activities sufficient to render ethenolysis applicable to the industrial-scale production of linear α-olefins (LAOs) and other terminal-olefin products.

  12. Cyclic alkyl amino carbene (CAAC) ruthenium complexes as remarkably active catalysts for ethenolysis

    DOE PAGES

    Marx, Vanessa M.; Sullivan, Alexandra H.; Melaimi, Mohand; ...

    2014-12-17

    In this paper, an expanded family of ruthenium-based metathesis catalysts bearing cyclic alkyl amino carbene (CAAC) ligands was prepared. These catalysts exhibited exceptional activity in the ethenolysis of the seed-oil derivative methyl oleate. In many cases, catalyst turnover numbers (TONs) of more than 100,000 were achieved, at a catalyst loading of only 3 ppm. Remarkably, the most active catalyst system was able to achieve a TON of 340 000, at a catalyst loading of only 1 ppm. Finally, this is the first time a series of metathesis catalysts has exhibited such high performance in cross-metathesis reactions employing ethylene gas, withmore » activities sufficient to render ethenolysis applicable to the industrial-scale production of linear α-olefins (LAOs) and other terminal-olefin products.« less

  13. Alkene metathesis: the search for better catalysts.

    PubMed

    Deshmukh, Prashant H; Blechert, Siegfried

    2007-06-28

    Alkene metathesis catalyst development has made significant progress over recent years. Research in metathesis catalyst design has endeavoured to tackle three key issues: those of (i) catalyst efficiency and activity, (ii) substrate scope and selectivity--particularly stereoselective metathesis reactions--and (iii) the minimization of metal impurities and catalyst recycling. This article describes a brief history of metathesis catalyst development, followed by a survey of more recent research, with a particular emphasis on ruthenium catalysts.

  14. Fischer-Tropsch Synthesis on Ceramic Monolith-Structured Catalysts

    SciTech Connect

    Wang, Yong; Liu, Wei

    2009-04-19

    This paper reports recent research results about impact of different catalyst bed configurations on FT reaction product distribution. A CoRe/γ-alumina catalyst is prepared in bulk particle form and tested in the packed bed reactor at a size of 60 to 100 mesh. The same catalyst is ball milled and coated on a ceramic monolith support structure of channel size about 1mm. The monolith catalyst module is tested in two different ways, as a whole piece and as well-defined channels. Steady-state reaction conversion is measured at various temperatures under constant H2/CO feed ratio of 2 and reactor pressure of 25 bar. Detailed product analysis is performed. Significant formation of wax is evident with the packed particle bed and with the monolith catalyst that is improperly packed. By contrast, the wax formation is not detected in the liquid product by confining the reactions inside the monolith channel. This study presents an important finding about the structured catalyst/reactor system that the product distribution highly depends on the way how the structured reactor is set up. Even if the same catalyst and same reaction conditions (T, P, H2/oil ratio) are used, hydrodynamics (or flow conditions) inside a structured channel can have a significant impact on the product distribution.

  15. The generation of efficient supported (Heterogeneous) olefin metathesis catalysts

    SciTech Connect

    Grubbs, Robert H

    2013-04-05

    Over the past decade, a new family of homogeneous metathesis catalysts has been developed that will tolerate most organic functionalities as well as water and air. These homogeneous catalysts are finding numerous applications in the pharmaceutical industry as well as in the production of functional polymers. In addition the catalysts are being used to convert seed oils into products that can substitute for those that are now made from petroleum products. Seed oils are unsaturated, contain double bonds, and are a ready source of linear hydrocarbon fragments that are specifically functionalized. To increase the number of applications in the area of biomaterial conversion to petrol chemicals, the activity and efficiency of the catalysts need to be as high as possible. The higher the efficiency of the catalysts, the lower the cost of the conversion and a larger number of practical applications become available. Active supported catalysts were prepared and tested in the conversion of seed oils and other important starting materials. The outcome of the work was successful and the technology has been transferred to a commercial operation to develop viable applications of the discovered systems. A biorefinery that converts seed oils is under construction in Indonesia. The catalysts developed in this study will be considered for the next generation of operations.

  16. Direct liquefaction of wood using nickel catalysts

    SciTech Connect

    Boocock, D.G.B.; Mackay, D.; Franco, H.

    1980-01-01

    In most the studies hydrogen has been used as a reducing agent and Raney nickel has been employed as catalyst, but in view of the low hydrogen uptake observed with mature catalyst some experiments were performed in the absence of hydrogen and these have yielded very encouraging results. An earlier paper described the complete liquefaction and gasification of fast-growing hybrid poplar. The wood (< 0.5 mm mesh) was suspended in water and treated with hydrogen in a well stirred and sparged autoclave using an initial pressure (24/sup 0/C) of 10.3 MPa and reaction temperatures of 325 to 375/sup 0/C. In all cases Raney-nickel was used as catalyst. In these single batch reactions hydrogen uptake was high and considerable wood gasification occurred. For example, for the highest catalyst/wood mass ratio of 0.2, 50g of wood at 350/sup 0/C consumed 3.8g of hydrogen and produced 1.3g of carbon dioxide, 16.0g of methane, 4.4g of saturated C/sub 2/ to C/sub 4/ alkanes and 8.0g of oil. No carbon monoxide was produced. The oil products contained 10 to 12 per cent oxygen and had viscosities of 700 to 2200 MPa.s at room temperature and heating values of 37 to 41 MJ.kg/sup -1/. The beneficial effect of prolonged use of the catalyst in extended batch reactions has now been examined. Reported are some results from these extended batch reactions and from runs in which hydrogen was not used. Also addressed is the problem of the wood feed system for possible commercial application.

  17. Catalysts for electrochemical generation of oxygen

    NASA Technical Reports Server (NTRS)

    Hagans, P.; Yeager, E.

    1978-01-01

    Single crystal surfaces of platinum and gold and transition metal oxides of the spinel type were studied to find more effective catalysts for the electrolytic evolution of oxygen and to understand the mechanism and kinetics for the electrocatalysis in relation to the surface electronic and lattice properties of the catalyst. The single crystal studies involve the use of low energy electron diffraction (LEED) and Auger electron spectroscopy as complementary tools to the electrochemical measurements. Modifications to the transfer system and to the thin-layer electrochemical cell used to facilitate the transfer between the ultrahigh vacuum environment of the electron surface physics equipment and the electrochemical environment with a minimal possibility of changes in the surface structure, are described. The electrosorption underpotential deposition of Pb onto the Au(111), (100) and (110) single crystal surfaces with the thin-layer cell-LEED-Auger system is discussed as well as the synthesis of spinels for oxygen evolution studies.

  18. Startup procedure for reforming catalysts

    SciTech Connect

    McHale, W.D.; Schoennagel, H.J.

    1984-08-14

    Process for reforming a hydrocarbon charge under reforming conditions in a reforming zone containing a sulfur-sensitive metal containing reforming catalyst wherein over-cracking of the charge stock and excessive temperature rise in the reforming zone is suppressed by pre-conditioning the catalyst, prior to contact with the charge, with a reformate of specified octane number and aromatics content.

  19. Catalysts for low temperature oxidation

    DOEpatents

    Toops, Todd J.; Parks, III, James E.; Bauer, John C.

    2016-03-01

    The invention provides a composite catalyst containing a first component and a second component. The first component contains nanosized gold particles. The second component contains nanosized platinum group metals. The composite catalyst is useful for catalyzing the oxidation of carbon monoxide, hydrocarbons, oxides of nitrogen, and other pollutants at low temperatures.

  20. Transition metal sulfide loaded catalyst

    DOEpatents

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

    1994-04-26

    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.

  1. Transition metal sulfide loaded catalyst

    DOEpatents

    Maroni, Victor A.; Iton, Lennox E.; Pasterczyk, James W.; Winterer, Markus; Krause, Theodore R.

    1994-01-01

    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.

  2. Doped palladium containing oxidation catalysts

    SciTech Connect

    Mohajeri, Nahid

    2014-02-18

    A supported oxidation catalyst includes a support having a metal oxide or metal salt, and mixed metal particles thereon. The mixed metal particles include first particles including a palladium compound, and second particles including a precious metal group (PMG) metal or PMG metal compound, wherein the PMG metal is not palladium. The oxidation catalyst may also be used as a gas sensor.

  3. Zeolites for reforming catalysts

    SciTech Connect

    Kao, J.L.; Nadler, M.; Potter, M.J.; Martir, R.V.

    1991-01-22

    This patent describes a reforming catalyst exhibiting enhanced selectivity, activity, and activity maintenance. It comprises: zeolite crystals having a pH within the range of 9.4 to 10.0, wherein the pH is determined by measuring pH of supernatent liquid from a mixture of one part of the zeolite crystals with ten parts of dionized water by weight, and comprising exchangeable cations and at least one catalytically active metal selected from the group consisting of Group VII of the Periodic Table of Elements, tin and germanium. This patten also describes a process for treating zeolite to have a pH within a range effective in imparting enhanced activity, selectivity and activity maintenance to catalysts loaded onto the zeolite. The process comprising washing zeolite with an aqueous liquid in a manner so as to result with zeolite having a pH within the pH range of 9.4 to 10.0. The PH of supernatent liquid from a mixture of one part of the zeolite crystals with ten parts of dionized water by weight.

  4. Catalyst design for biorefining.

    PubMed

    Wilson, Karen; Lee, Adam F

    2016-02-28

    The quest for sustainable resources to meet the demands of a rapidly rising global population while mitigating the risks of rising CO2 emissions and associated climate change, represents a grand challenge for humanity. Biomass offers the most readily implemented and low-cost solution for sustainable transportation fuels, and the only non-petroleum route to organic molecules for the manufacture of bulk, fine and speciality chemicals and polymers. To be considered truly sustainable, biomass must be derived from resources which do not compete with agricultural land use for food production, or compromise the environment (e.g. via deforestation). Potential feedstocks include waste lignocellulosic or oil-based materials derived from plant or aquatic sources, with the so-called biorefinery concept offering the co-production of biofuels, platform chemicals and energy; analogous to today's petroleum refineries which deliver both high-volume/low-value (e.g. fuels and commodity chemicals) and low-volume/high-value (e.g. fine/speciality chemicals) products, thereby maximizing biomass valorization. This article addresses the challenges to catalytic biomass processing and highlights recent successes in the rational design of heterogeneous catalysts facilitated by advances in nanotechnology and the synthesis of templated porous materials, as well as the use of tailored catalyst surfaces to generate bifunctional solid acid/base materials or tune hydrophobicity.

  5. Catalysts to reduce NO.sub.x in an exhaust gas stream and methods of preparation

    DOEpatents

    Koermer, Gerald S [Basking Ridge, NJ; Moini, Ahmad [Princeton, NJ; Furbeck, Howard [Hamilton, NJ; Castellano, Christopher R [Ringoes, NJ

    2012-05-08

    Catalysts, systems and methods are described to reduce NO.sub.x emissions of an internal combustion engine. In one embodiment, an emissions treatment system for an exhaust stream is provided having a catalyst comprising silver on a particulate alumina support, the silver having a diameter of less than about 20 nm. Methods of manufacturing catalysts are described in which ionic silver is impregnated on particulate hydroxylated alumina particles.

  6. Catalysts to reduce NO.sub.x in an exhaust gas stream and methods of preparation

    DOEpatents

    Castellano, Christopher R.; Moini, Ahmad; Koermer, Gerald S.; Furbeck, Howard; Schmieg, Steven J.; Blint, Richard J.

    2011-05-17

    Catalysts, systems and methods are described to reduce NO.sub.x emissions of an internal combustion engine. In one embodiment, an emissions treatment system for an exhaust stream is provided having a catalyst comprising silver and a platinum group metal on a particulate alumina support, the atomic fraction of the platinum group metal being less than or equal to about 0.25. Methods of manufacturing catalysts are described in which silver is impregnated on alumina particles.

  7. Supported molten-metal catalysts

    DOEpatents

    Datta, Ravindra; Singh, Ajeet; Halasz, Istvan; Serban, Manuela

    2001-01-01

    An entirely new class of catalysts called supported molten-metal catalysts, SMMC, which can replace some of the existing precious metal catalysts used in the production of fuels, commodity chemicals, and fine chemicals, as well as in combating pollution. SMMC are based on supporting ultra-thin films or micro-droplets of the relatively low-melting (<600.degree. C.), inexpensive, and abundant metals and semimetals from groups 1, 12, 13, 14, 15 and 16, of the periodic table, or their alloys and intermetallic compounds, on porous refractory supports, much like supported microcrystallites of the traditional solid metal catalysts. It thus provides orders of magnitude higher surface area than is obtainable in conventional reactors containing molten metals in pool form and also avoids corrosion. These have so far been the chief stumbling blocks in the application of molten metal catalysts.

  8. Ethanol synthesis and water gas shift over bifunctional sulfide catalysts. Technical progress report, March--May 1992

    SciTech Connect

    Klier, K.; Herman, R.G.; Richards-Babb, M.

    1992-06-01

    During this quarter, the high pressure (up to 100 atm), high temperature (up to 350{degrees}C) catalyst testing system was rebuilt with clean tubing, etc. A new preparation of MoS{sub 2} catalyst was carried out, and this catalyst will be doped with alkali and tested during the next quarter of research.

  9. Surface structure and functionality of bauxite-based catalysts in the hydrotreating of heavy crudes

    SciTech Connect

    Vecchi, C.; Marengo, S.; Iannibello, A.; Girelli, A.

    1982-09-01

    The functionality of Mo- and W-containing catalysts in the hydrotreating of heavy feedstocks in trickle flow conditions was compared. The catalysts included a bauxite support with an absorbed layer of Mo and/or W prepared by a step addition technique. Alumina-supported catalysts were studied also, and a strict correlation was observed between the properties of the bauxite-based catalysts and those of the corresponding alumina-based systems. The Mo-based systems performed better as catalysts than the W systems. NMR results revealed a deeper insight into the structural modifications induced in the feedstock by catalytic hydroprocessing with these catalysts. The catalysis studies of the feedstocks showed that the removal of the ethero-atoms lowered the aromaticity of the samples and the degree of condensation of the aromatic structures with only a moderate amount of hydrogenation of the aromatic rings. (BLM)

  10. Iridium-Doped Ruthenium Oxide Catalyst for Oxygen Evolution

    NASA Technical Reports Server (NTRS)

    Valdez, Thomas I.; Narayan, Sri R.; Billings, Keith J.

    2011-01-01

    NASA requires a durable and efficient catalyst for the electrolysis of water in a polymer-electrolyte-membrane (PEM) cell. Ruthenium oxide in a slightly reduced form is known to be a very efficient catalyst for the anodic oxidation of water to oxygen, but it degrades rapidly, reducing efficiency. To combat this tendency of ruthenium oxide to change oxidation states, it is combined with iridium, which has a tendency to stabilize ruthenium oxide at oxygen evolution potentials. The novel oxygen evolution catalyst was fabricated under flowing argon in order to allow the iridium to preferentially react with oxygen from the ruthenium oxide, and not oxygen from the environment. Nanoparticulate iridium black and anhydrous ruthenium oxide are weighed out and mixed to 5 18 atomic percent. They are then heat treated at 300 C under flowing argon (in order to create an inert environment) for a minimum of 14 hours. This temperature was chosen because it is approximately the creep temperature of ruthenium oxide, and is below the sintering temperature of both materials. In general, the temperature should always be below the sintering temperature of both materials. The iridium- doped ruthenium oxide catalyst is then fabricated into a PEM-based membrane- electrode assembly (MEA), and then mounted into test cells. The result is an electrolyzer system that can sustain electrolysis at twice the current density, and at the same efficiency as commercial catalysts in the range of 100-200 mA/sq cm. At 200 mA/sq cm, this new system operates at an efficiency of 85 percent, which is 2 percent greater than commercially available catalysts. Testing has shown that this material is as stable as commercially available oxygen evolution catalysts. This means that this new catalyst can be used to regenerate fuel cell systems in space, and as a hydrogen generator on Earth.

  11. Development plus kinetic and mechanistic studies of a prototype supported-nanoparticle heterogeneous catalyst formation system in contact with solution: Ir(1,5-COD)Cl/gamma-Al2O3 and its reduction by H2 to Ir(0)n/gamma-Al2O3.

    PubMed

    Mondloch, Joseph E; Wang, Qi; Frenkel, Anatoly I; Finke, Richard G

    2010-07-21

    An important question and hence goal in catalysis is how best to transfer the synthetic and mechanistic insights gained from the modern revolution in nanoparticle synthesis, characterization, and catalysis to prepare the next generation of improved, supported-nanoparticle heterogeneous catalysts. It is precisely this question and to-date somewhat elusive goal which are addressed by the present work. More specifically, the global hypothesis investigated herein is that the use of speciation-controlled, well-characterized, solid oxide supported-organometallic precatalysts in contact with solution will lead to the next generation of better composition, size- and shape-controlled, as well as highly active and reproducible, supported-nanoparticle heterogeneous catalysts-ones that can also be understood kinetically and mechanistically. Developed herein are eight criteria defining a prototype system for supported-nanoparticle heterogeneous catalyst formation in contact with solution. The initial prototype system explored is the precatalyst, Ir(1,5-COD)Cl/gamma-Al(2)O(3) (characterized via ICP, CO adsorption, IR, and XAFS spectroscopies), and the well-defined product, Ir(0)(n)/gamma-Al(2)O(3) (characterized by reaction stoichiometry, TEM, and XAFS). The Ir(0)(n)/gamma-Al(2)O(3) system proved to be a highly active and long-lived catalyst in the simple test reaction of cyclohexene hydrogenation and in comparison to two literature Ir(0)(n)/Al(2)O(3) heterogeneous catalysts examined under identical conditions. High activity (2.2-4.8-fold higher than that of the literature Ir(0)(n)/Al(2)O(3) catalysts tested under the same conditions) and good lifetime (> or = 220,000 total turnovers of cyclohexene hydrogenation) are observed, in part by design since only acetone solvent, cyclohexene, and H(2) are possible ligands in the resultant "weakly ligated/labile-ligand" supported nanoclusters. Significantly, the Ir(1,5-COD)Cl/gamma-Al(2)O(3) + H(2) --> Ir(0)(n)/gamma-Al(2)O(3

  12. Evaluation of Regenerated Catalyst for Mercury Speciation

    SciTech Connect

    Dennis Laudal

    2007-06-01

    In March of 2005, U.S. Environmental Protection Agency (EPA) promulgated the Clean Air Mercury Rule (CAMR). Mercury from coal-fired power plants was to be reduced from the current 48 to 38 tons/yr by 2010 and then 15 tons/yr by 2018. It is expected that the first phase reduction of {approx}21% will be achieved by cobenefits that will occur as a result of installing additional selective catalytic reduction (SCR) and flue gas desulfurization (FGD) systems to meet the new Clean Air Interstate Rule (CAIR). Detroit Edison (DTE) is installing SCR at all four units at its Monroe Station and will eventually install wet-FGD systems. As such, the Electric Power Research Institute (EPRI), the U.S. Department of Energy (DOE), and DTE have contracted with the Energy & Environmental Research Center (EERC) to determine the extent of mercury oxidation that occurs at Monroe Station. The EERC originally did mercury speciation sampling at Monroe Station in 2004 and then went back in 2005 to determine if any changes occurred as a result of catalyst aging. During the second test, in addition to measuring the mercury speciation at the inlet and outlet of the SCR, the EERC also completed sampling at a location between the catalyst layers. The results are shown in Table 1. In Table 1, the results show that {approx}40% of the Hg was in oxidized form (Hg{sup 2+}) at the inlet and nearly 100% Hg{sup 2+} at the outlet. The results at the midpoint were between 40% and 100%. As part of their overall strategy to reduce SCR costs, utilities and SCR vendors are attempting to regenerate catalyst layers that have degenerated over time. If these regenerated catalysts are used, the question remains as to the effect this process will have on the ability of these catalysts to oxidize mercury as well as reduce NO{sub x}. The current project is designed to measure the Hg speciation across an SCR using a regenerated catalyst. The results were compared to previous results to determine what, if any, changes

  13. Regeneration of a deactivated USY alkylation catalyst using supercritical isobutane

    SciTech Connect

    Daniel M. Ginosar; David N. Ghompson; Kyle C. Burch

    2005-01-01

    Off-line, in-situ alkylation activity recovery from a completely deactivated solid acid catalyst was examined in a continuous-flow reaction system employing supercritical isobutane. A USY zeolite catalyst was initially deactivated during the liquid phase alkylation of butene with isobutane in a single-pass reactor and then varying amounts of alkylation activity were recovered by passing supercritical isobutane over the catalyst bed at different reactivation conditions. Temperature, pressure and regeneration time were found to play important roles in the supercritical isobutane regeneration process when applied to a completely deactivated USY zeolite alkylation catalyst. Manipulation of the variables that influence solvent strength, diffusivity, surface desorption, hydride transfer rates, and coke aging, strongly influence regeneration effectiveness.

  14. Ceramic catalyst materials

    SciTech Connect

    Sault, A.G.; Gardner, T.J.; Hanprasopwattanna, A.; Reardon, J.; Datye, A.K.

    1995-08-01

    Hydrous titanium oxide (HTO) ion-exchange materials show great potential as ceramic catalyst supports due to an inherently high ion-exchange capacity which allows facile loading of catalytically active transition metal ions, and an ability to be cast as thin films on virtually any substrate. By coating titania and HTO materials onto inexpensive, high surface area substrates such as silica and alumina, the economics of using these materials is greatly improved, particularly for the HTO materials, which are substantially more expensive in the bulk form than other oxide supports. In addition, the development of thin film forms of these materials allows the catalytic and mechanical properties of the final catalyst formulation to be separately engineered. In order to fully realize the potential of thin film forms of titania and HTO, improved methods for the deposition and characterization of titania and HTO films on high surface area substrates are being developed. By varying deposition procedures, titania film thickness and substrate coverage can be varied from the submonolayer range to multilayer thicknesses on both silica and alumina. HTO films can also be formed, but the quality and reproducibility of these films is not nearly as good as for pure titania films. The films are characterized using a combination of isopropanol dehydration rate measurements, point of zero charge (PZC) measurements, BET surface area, transmission electron microscopy (TEM), and elemental analysis. In order to assess the effects of changes in film morphology on catalytic activity, the films are being loaded with MoO{sub 3} using either incipient wetness impregnation or ion-exchange of heptamolybdate anions followed by calcining. The MoO{sub 3} is then sulfided to form MOS{sub 2}, and tested for catalytic activity using pyrene hydrogenation and dibenzothiophene (DBT) desulfurization, model reactions that simulate reactions occurring during coal liquefaction.

  15. Catalyst deactivation in residue hydrocracking

    SciTech Connect

    Oballa, M.C.; Wong, C.; Krzywicki, A.

    1994-12-31

    The existence of a computer-controlled bench scale hydrocracking units at the authors site has made cheaper the non-stop running of experiments for long periods of time. It was, therefore possible to show, at minimal costs, when three hydrocracking catalysts in service reach their maximum lifetime. Different parameters which are helpful for catalyst life and activity predictions were calculated, e.g., relative catalyst age and the effectiveness factor. Experimental results compared well with model, giving them the minimum and maximum catalyst lifetime, as well as the deactivation profile with regard to sulfur and metals removal. Reaction rate constants for demetallization and desulfurization were also determined. Six commercial catalysts were evaluated at short term runs and the three most active were used for long term runs. Out of three catalysts tested for deactivation at long term runs, it was possible to choose one whose useful life was higher than the others. All runs were carried out in a Robinson-Mahoney continuous flow stirred tank reactor, using 50/50 volumetric mixture of Cold Lake/Lloydminster atmospheric residue and NiMo/Al{sub 2}O{sub 3} catalyst.

  16. Full Scale Alternative Catalyst Testing for Bosch Reactor Optimization

    NASA Technical Reports Server (NTRS)

    Barton, Katherine; Abney, Morgan B.

    2011-01-01

    Current air revitalization technology onboard the International Space Station (ISS) cannot provide complete closure of the oxygen and hydrogen loops. This makes re-supply necessary, which is possible for missions in low Earth orbit (LEO) like the ISS, but unviable for long term space missions outside LEO. In comparison, Bosch technology reduces carbon dioxide with hydrogen, traditionally over a steel wool catalyst, to create water and solid carbon. The Bosch product water can then be fed to the oxygen generation assembly to produce oxygen for crew members and hydrogen necessary to reduce more carbon dioxide. Bosch technology can achieve complete oxygen loop closure, but has many undesirable factors that result in a high energy, mass, and volume system. Finding a different catalyst with an equal reaction rate at lower temperatures with less catalyst mass and longer lifespan would make a Bosch flight system more feasible. Developmental testing of alternative catalysts for the Bosch has been performed using the Horizontal Bosch Test Stand. Nickel foam, nickel shavings, and cobalt shavings were tested at 500 C and compared to the original catalyst, steel wool. This paper presents data and analysis on the performance of each catalyst tested at comparable temperatures and recycle flow rates.

  17. Development of GREET Catalyst Module

    SciTech Connect

    Wang, Zhichao; Dunn, Jennifer B.; Cronauer, Donald C.

    2014-09-01

    Catalysts are critical inputs for many pathways that convert biomass into biofuels. Energy consumption and greenhouse gas (GHG) emissions during the production of catalysts and chemical inputs influence the life-cycle energy consumption, and GHG emissions of biofuels and need to be considered in biofuel life-cycle analysis (LCA). In this report, we develop energy and material flows for the production of three different catalysts (tar reforming, alcohol synthesis, Zeolite Socony Mobil-5 [ZSM-5]) and two chemicals (olivine, dimethyl ether of polyethylene glycol [DEPG]). These compounds and catalysts are now included in the Greenhouse Gases, Regulated Emissions and Energy Use in Transportation (GREET™) catalyst module. They were selected because they are consumed in existing U.S. Department of Energy (DOE) analyses of biofuel processes. For example, a thermochemical ethanol production pathway (indirect gasification and mixed alcohol synthesis) developed by the National Renewable Energy Laboratory (NREL) uses olivine, DEPG, and tar reforming and alcohol synthesis catalysts (Dutta et al., 2011). ZSM-5 can be used in biofuel production pathways such as catalytic upgrading of sugars into hydrocarbons (Biddy and Jones, 2013). Other uses for these compounds and catalysts are certainly possible. In this report, we document the data sources and methodology we used to develop material and energy flows for the catalysts and compounds in the GREET catalyst module. In Section 2 we focus on compounds used in the model Dutta et al. (2011) developed. In Section 3, we report material and energy flows associated with ZSM-5 production. Finally, in Section 4, we report results.

  18. On-demand Hydrogen Production from Organosilanes at Ambient Temperature Using Heterogeneous Gold Catalysts

    PubMed Central

    Mitsudome, Takato; Urayama, Teppei; Kiyohiro, Taizo; Maeno, Zen; Mizugaki, Tomoo; Jitsukawa, Koichiro; Kaneda, Kiyotomi

    2016-01-01

    An environmentally friendly (“green”), H2-generation system was developed that involved hydrolytic oxidation of inexpensive organosilanes as hydrogen storage materials with newly developed heterogeneous gold nanoparticle catalysts. The gold catalyst functioned well at ambient temperature under aerobic conditions, providing efficient production of pure H2. The newly developed size-selective gold nanoparticle catalysts could be separated easily from the reaction mixture containing organosilanes, allowing an on/off-switchable H2-production by the introduction and removal of the catalyst. This is the first report of an on/off-switchable H2-production system employing hydrolytic oxidation of inexpensive organosilanes without requiring additional energy. PMID:27883063

  19. Toward efficient asymmetric carbon-carbon bond formation: continuous flow with chiral heterogeneous catalysts.

    PubMed

    Tsubogo, Tetsu; Yamashita, Yasuhiro; Kobayashi, Shū

    2012-10-22

    A chiral Ca catalyst based on CaCl(2) with a chiral ligand was developed and applied to the asymmetric 1,4-addition of 1,3-dicarbonyl compounds to nitroalkenes as a model system. To address product inhibition issues, the Ca catalyst was applied to continuous flow with a chiral heterogeneous catalyst. The continuous flow system using a newly synthesized, polymer-supported Pybox was successfully employed, and the TON was improved 25-fold compared with those of the previous Ca(OR)(2) catalysts.

  20. On-demand Hydrogen Production from Organosilanes at Ambient Temperature Using Heterogeneous Gold Catalysts

    NASA Astrophysics Data System (ADS)

    Mitsudome, Takato; Urayama, Teppei; Kiyohiro, Taizo; Maeno, Zen; Mizugaki, Tomoo; Jitsukawa, Koichiro; Kaneda, Kiyotomi

    2016-11-01

    An environmentally friendly (“green”), H2-generation system was developed that involved hydrolytic oxidation of inexpensive organosilanes as hydrogen storage materials with newly developed heterogeneous gold nanoparticle catalysts. The gold catalyst functioned well at ambient temperature under aerobic conditions, providing efficient production of pure H2. The newly developed size-selective gold nanoparticle catalysts could be separated easily from the reaction mixture containing organosilanes, allowing an on/off-switchable H2-production by the introduction and removal of the catalyst. This is the first report of an on/off-switchable H2-production system employing hydrolytic oxidation of inexpensive organosilanes without requiring additional energy.

  1. Emission Abatement System

    DOEpatents

    Bromberg, Leslie; Cohn, Daniel R.; Rabinovich, Alexander

    2003-05-13

    Emission abatement system. The system includes a source of emissions and a catalyst for receiving the emissions. Suitable catalysts are absorber catalysts and selective catalytic reduction catalysts. A plasma fuel converter generates a reducing gas from a fuel source and is connected to deliver the reducing gas into contact with the absorber catalyst for regenerating the catalyst. A preferred reducing gas is a hydrogen rich gas and a preferred plasma fuel converter is a plasmatron. It is also preferred that the absorber catalyst be adapted for absorbing NO.sub.x.

  2. ZSM-5 catalyst developed for toluene disproportionation

    SciTech Connect

    Han, S.; Shihabi, D.S. ); Absil, R.P.L.; Huang, Y.Y.; Leiby, S.M.; Marler, D.O.; McWilliams, J.P. )

    1989-08-21

    Toluene disproportionation over a new ZSM-5 catalyst formulation shows better activity and stability compared to the current Mobil Toluene disproportionation (MTDP) catalyst. Subsequent adiabatic pilot plant operations confirmed the activity and stability of the new catalyst. This process flexibility is expected to translate into considerable economic advantages for the process using the new catalyst formulation.

  3. Chalcogen catalysts for polymer electrolyte fuel cell

    DOEpatents

    Zelenay, Piotr; Choi, Jong-Ho; Alonso-Vante, Nicolas; Wieckowski, Andrzej; Cao, Dianxue

    2010-08-24

    A methanol-tolerant cathode catalyst and a membrane electrode assembly for fuel cells that includes such a cathode catalyst. The cathode catalyst includes a support having at least one transition metal in elemental form and a chalcogen disposed on the support. Methods of making the cathode catalyst and membrane electrode assembly are also described.

  4. Catalyst support effects on hydrogen spillover

    NASA Astrophysics Data System (ADS)

    Karim, Waiz; Spreafico, Clelia; Kleibert, Armin; Gobrecht, Jens; Vandevondele, Joost; Ekinci, Yasin; van Bokhoven, Jeroen A.

    2017-01-01

    Hydrogen spillover is the surface migration of activated hydrogen atoms from a metal catalyst particle, on which they are generated, onto the catalyst support. The phenomenon has been much studied and its occurrence on reducible supports such as titanium oxide is established, yet questions remain about whether hydrogen spillover can take place on nonreducible supports such as aluminium oxide. Here we use the enhanced precision of top-down nanofabrication to prepare controlled and precisely tunable model systems that allow us to quantify the efficiency and spatial extent of hydrogen spillover on both reducible and nonreducible supports. We place multiple pairs of iron oxide and platinum nanoparticles on titanium oxide and aluminium oxide supports, varying the distance between the pairs from zero to 45 nanometres with a precision of one nanometre. We then observe the extent of the reduction of the iron oxide particles by hydrogen atoms generated on the platinum using single-particle in situ X-ray absorption spectromicroscopy applied simultaneously to all particle pairs. The data, in conjunction with density functional theory calculations, reveal fast hydrogen spillover on titanium oxide that reduces remote iron oxide nanoparticles via coupled proton-electron transfer. In contrast, spillover on aluminium oxide is mediated by three-coordinated aluminium centres that also interact with water and that give rise to hydrogen mobility competing with hydrogen desorption; this results in hydrogen spillover about ten orders of magnitude slower than on titanium oxide and restricted to very short distances from the platinum particle. We anticipate that these observations will improve our understanding of hydrogen storage and catalytic reactions involving hydrogen, and that our approach to creating and probing model catalyst systems will provide opportunities for studying the origin of synergistic effects in supported catalysts that combine multiple functionalities.

  5. HYBRID HETEROGENEOUS CATALYSTS FOR HYDROGENATION OF CARBON DIOXIDE

    SciTech Connect

    Licia M. Petkovic; Harry W. Rollins; Daniel M. Ginosar; Kyle C. Burch

    2006-09-01

    reactor and a flow of 100 cm3/min of a 10:90 H2:Ar mixture was passed through the catalyst bed while the temperature was increased from room temperature to 513 K at 1.8 K/min and held at 513 K for 15 h. A reactant gas mixture composed by 10 cm3/min of CO2 and 30 cm3/min of H2 was then passed through the catalyst bed and the reaction products monitored by on-line gas chromatographic analyses using an SRI Multiple Gas Analyzer #2 equipped with 3 columns (MoleSieve 13X, Hayesep-D, and MXT-1) and 3 detectors (TCD, FID, and FID-methanizer). This GC system allowed for quantification of inert gases, CO, CO2, methanol, dimethylether, higher alcohols, water, and hydrocarbons up to C20. One hundred milligrams of a commercial syngas-to-methanol catalyst along with the same amount of a commercial zeolite catalyst was utilized under the same reaction conditions for comparison purposes. These catalysts were utilized either in two-layers (Com1) or mixed together (Com2). Results and Discussion Under the conditions applied in this study, the main reaction products were CO, CH3OH, CH3OCH3, and H2O. Methanol and dimethylether production rates and selectivities with respect to CO formation are presented in Figures 1 and 2, respectively. Although the activity of the synthesized catalysts did not surpass the commercial catalysts, the selectivity to oxygenates with respect to CO on most of the synthesized catalysts were better than on the commercial catalysts. For example, cat

  6. Catalyst Additives to Enhance Mercury Oxidation and Capture

    SciTech Connect

    Jared W. Cannon; Thomas K. Gale

    2005-06-30

    Preliminary research has shown that SCR catalysts employed for nitrogen-oxide reduction can effectively oxidize mercury. This report discusses initial results from fundamental investigations into the behavior of mercury species in the presence of SCR catalysts at Southern Research Institute. The testing was performed at Southern Research's Catalyst Test Facility, a bench-scale reactor capable of simulating gas-phase reactions occurring in coal-fired utility pollution-control equipment. Three different SCR catalysts are currently being studied in this project--honeycomb-type, plate-type, and a hybrid-type catalyst. The catalysts were manufactured and supplied by Cormetech Inc., Hitachi America Ltd., and Haldor-Topsoe Inc., respectively. Parametric testing was performed to investigate the contribution of flue-gas chemistry on mercury oxidation via SCR catalysts. Methods and procedures for experimental testing continue to be developed to produce the highest quality mercury-oxidation data. During this past quarter, it was discovered that long periods (12 - 24 hours) are required to equilibrate the catalysts in the system. In addition, after the system has been equilibrated, operational changes to temperature, gas concentration, or flow rate shifts the equilibrium, and steady-state must be reestablished, which can require as much as twelve additional hours per condition change. In the last quarter of testing, it was shown that the inclusion of ammonia had a strong effect on the oxidation of mercury by SCR catalysts, both in the short-term (a transitional period of elemental and oxidized mercury off gassing) and the long-term (less steady-state mercury oxidation). All experiments so far have focused on testing the catalysts in a simulated Powder River Basin (PRB) flue-gas environment, which contains lower sulfur and chlorine than produced by other coals. In the next quarter, parametric testing will be expanded to include flue gases simulating power plants burning

  7. Textured catalysts, methods of making textured catalysts, and methods of catalyzing reactions conducted in hydrothermal conditions

    DOEpatents

    Werpy, Todd [West Richland, WA; Wang, Yong [Richland, WA

    2003-12-30

    A textured catalyst having a hydrothermally-stable support, a metal oxide and a catalyst component is described. Methods of conducting aqueous phase reactions that are catalyzed by a textured catalyst are also described. The invention also provides methods of making textured catalysts and methods of making chemical products using a textured catalyst.

  8. High Temperature Membrane & Advanced Cathode Catalyst Development

    SciTech Connect

    Protsailo, Lesia

    2006-04-20

    Current project consisted of three main phases and eighteen milestones. Short description of each phase is given below. Table 1 lists program milestones. Phase 1--High Temperature Membrane and Advanced Catalyst Development. New polymers and advanced cathode catalysts were synthesized. The membranes and the catalysts were characterized and compared against specifications that are based on DOE program requirements. The best-in-class membranes and catalysts were downselected for phase 2. Phase 2--Catalyst Coated Membrane (CCM) Fabrication and Testing. Laboratory scale catalyst coated membranes (CCMs) were fabricated and tested using the down-selected membranes and catalysts. The catalysts and high temperature membrane CCMs were tested and optimized. Phase 3--Multi-cell stack fabrication. Full-size CCMs with the down-selected and optimized high temperature membrane and catalyst were fabricated. The catalyst membrane assemblies were tested in full size cells and multi-cell stack.

  9. Tetranuclear Zn/4f coordination clusters as highly efficient catalysts for Friedel-Crafts alkylation.

    PubMed

    Griffiths, Kieran; Kumar, Prashant; Akien, Geoffrey R; Chilton, Nicholas F; Abdul-Sada, Alaa; Tizzard, Graham J; Coles, Simon J; Kostakis, George E

    2016-06-14

    A series of custom-designed, high yield, isoskeletal tetranuclear Zn/4f coordination clusters showing high efficiency as catalysts with low catalytic loadings in Friedel-Crafts alkylation are described for the first time. The possibility of altering the 4f centers in these catalysts without altering the core topology allows us to further confirm their stability via EPR and NMR, as well to gain insights into the plausible reaction mechanism, showcasing the usefulness of these bimetallic systems as catalysts.

  10. A Robust, Air-Stable, Reusable Ruthenium Catalyst for Dehydrogenation of Ammonia Borane

    PubMed Central

    Conley, Brian L.; Guess, Denver; Williams, Travis J.

    2011-01-01

    We describe an efficient homogeneous ruthenium catalyst for the dehydrogenation of ammonia borane (AB). This catalyst liberates greater than 2 equivalents of H2 and up to 4.6 system wt% H2 from concentrated AB suspensions under air. Importantly, this catalyst is robust, delivering several cycles of dehydrogenation at high [AB] without loss of catalytic activity, even with exposure to air and water. PMID:21827173

  11. Microwave-hydrothermal synthesis and characterization of nanostructured copper substituted ZnM2O4 (M = Al, Ga) spinels as precursors for thermally stable Cu catalysts.

    PubMed

    Conrad, Franziska; Massue, Cyriac; Kühl, Stefanie; Kunkes, Edward; Girgsdies, Frank; Kasatkin, Igor; Zhang, Bingsen; Friedrich, Matthias; Luo, Yuan; Armbrüster, Marc; Patzke, Greta R; Behrens, Malte

    2012-03-21

    Nanostructured Cu(x)Zn(1-x)Al(2)O(4) with a Cu:Zn ratio of ¼:¾ has been prepared by a microwave-assisted hydrothermal synthesis at 150 °C and used as a precursor for Cu/ZnO/Al(2)O(3)-based catalysts. The spinel nanoparticles exhibit an average size of approximately 5 nm and a high specific surface area (above 250 m(2) g(-1)). Cu nanoparticles of an average size of 3.3 nm can be formed by reduction of the spinel precursor in hydrogen and the accessible metallic Cu(0) surface area of the reduced catalyst was 8 m(2) g(-1). The catalytic performance of the material in CO(2) hydrogenation and methanol steam reforming was compared with conventionally prepared Cu/ZnO/Al(2)O(3) reference catalysts. The observed lower performance of the spinel-based samples is attributed to a lack of synergetic interaction of the Cu nanoparticles with ZnO due to the incorporation of Zn(2+) in the stable spinel lattice. Despite its lower performance, however, the nanostructured nature of the spinel catalyst was stable after thermal treatment up to 500 °C in contrast to other Cu-based catalysts. Furthermore, a large fraction of the re-oxidized copper migrates back into the spinel upon calcination of the reduced catalyst, thereby enabling a regeneration of sintered catalysts after prolonged usage at high temperatures. Similarly prepared samples with Ga instead of Al exhibit a more crystalline catalyst with a spinel particle size around 20 nm. The slightly decreased Cu(0) surface area of 3.2 m(2) g(-1) due to less copper incorporation is not a significant drawback for the methanol steam reforming.

  12. The electron is a catalyst

    NASA Astrophysics Data System (ADS)

    Studer, Armido; Curran, Dennis P.

    2014-09-01

    The electron is an efficient catalyst for conducting various types of radical cascade reaction that proceed by way of radical and radical ion intermediates. But because electrons are omnipresent, catalysis by electrons often passes unnoticed. In this Review, a simple analogy between acid/base catalysis and redox catalysis is presented. Conceptually, the electron is a catalyst in much the same way that a proton is a catalyst. The 'electron is a catalyst' paradigm unifies mechanistically an assortment of synthetic transformations that otherwise have little or no apparent relationship. Diverse radical cascades, including unimolecular radical substitution reactions (SRN1-type chemistry), base-promoted homolytic aromatic substitutions (BHAS), radical Heck-type reactions, radical cross-dehydrogenative couplings (CDC), direct arene trifluoromethylations and radical alkoxycarbonylations, can all be viewed as electron-catalysed reactions.

  13. Secret Lives of Catalysts Revealed

    SciTech Connect

    Miquel Salmeron and Gabor Somorjai

    2008-10-15

    Miquel Salmeron and Gabor Somorjai of Berkeley Lab's Materials Sciences Division discuss the first-ever glimpse of nanoscale catalysts in action. More information: http://newscenter.lbl.gov/press-relea...

  14. Secret Lives of Catalysts Revealed

    ScienceCinema

    Miquel Salmeron and Gabor Somorjai

    2016-07-12

    Miquel Salmeron and Gabor Somorjai of Berkeley Lab's Materials Sciences Division discuss the first-ever glimpse of nanoscale catalysts in action. More information: http://newscenter.lbl.gov/press-relea...

  15. Catalyst for sodium chlorate decomposition

    NASA Technical Reports Server (NTRS)

    Wydeven, T.

    1972-01-01

    Production of oxygen by rapid decomposition of cobalt oxide and sodium chlorate mixture is discussed. Cobalt oxide serves as catalyst to accelerate reaction. Temperature conditions and chemical processes involved are described.

  16. The selective hydrogenation of crotonaldehyde over bimetallic catalysts

    SciTech Connect

    Schoeb, Ann M.

    1997-10-17

    The selective hydrogenation of crotonaldehyde has been investigated over a monometallic Pt/SiO2 catalyst and platinum bimetallic catalysts where the second metal was either silver, copper, or tin. The effects of addition of a second metal to the Pt/SiO2 system on the selectivity to crotyl alcohol were investigated. The Pt-Sn bimetallic catalysts were characterized by hydrogen chemisorption, 1H NMR and microcalorimetry. The Pt-Ag/SiO2 and Pt-Cu/SiO2 catalysts were characterized by hydrogen chemisorption. Pt-Sn/SiO2 catalysts selectively hydrogenated crotonaldehyde to crotyl alcohol and the method of preparation of these catalysts affected the selectivity. The most selective Pt-Sn/SiO2 catalysts for the hydrogenation of crotonaldehyde to crotyl alcohol were those in which the Sn precursor was dissolved in a HCl solution. Sn increased both the rate of formation of butyraldehyde and the rate of formation of crotyl alcohol. The Pt/SiO2, Pt-Ag/SiO2 and Pt-Cu/SiO2 catalysts produced only butyraldehyde. Initial heats of adsorption (~90 kJ/mol) measured using microcalorimetry were not affected by the presence of Sn on Pt. We can conclude that there is no through metal electronic interaction between Pt and Sn at least with respect to hydrogen surface bonds since the Pt and Pt-Sn at least with respect to hydrogen surface bonds since the Pt and Pt-Sn had similar initial heats of adsorption coupled with the invariance of the 1H NMR Knight shift.

  17. Organometallic catalysts for primary phosphoric acid fuel cells

    NASA Technical Reports Server (NTRS)

    Walsh, Fraser

    1987-01-01

    A continuing effort by the U.S. Department of Energy to improve the competitiveness of the phosphoric acid fuel cell by improving cell performance and/or reducing cell cost is discussed. Cathode improvement, both in performance and cost, available through the use of a class of organometallic cathode catalysts, the tetraazaannulenes (TAAs), was investigated. A new mixed catalyst was identified which provides improved cathode performance without the need for the use of a noble metal. This mixed catalyst was tested under load for 1000 hr. in full cell at 160 to 200 C in phosphoric acid H3PO4, and was shown to provide stable performance. The mixed catalyst contains an organometallic to catalyze electroreduction of oxygen to hydrogen peroxide and a metal to catalyze further electroreduction of the hydrogen peroxide to water. Cathodes containing an exemplar mixed catalyst (e.g., Co bisphenyl TAA/Mn) operate at approximately 650 mV vs DHE in 160 C, 85% H3PO4 with oxygen as reactant. In developing this mixed catalyst, a broad spectrum of TAAs were prepared, tested in half-cell and in a rotating ring-disk electrode system. TAAs found to facilitate the production of hydrogen peroxide in electroreduction were shown to be preferred TAAs for use in the mixed catalyst. Manganese (Mn) was identified as a preferred metal because it is capable of catalyzing hydrogen peroxide electroreduction, is lower in cost and is of less strategic importance than platinum, the cathode catalyst normally used in the fuel cell.

  18. Organometallic catalysts for primary phosphoric acid fuel cells

    NASA Astrophysics Data System (ADS)

    Walsh, Fraser

    1987-03-01

    A continuing effort by the U.S. Department of Energy to improve the competitiveness of the phosphoric acid fuel cell by improving cell performance and/or reducing cell cost is discussed. Cathode improvement, both in performance and cost, available through the use of a class of organometallic cathode catalysts, the tetraazaannulenes (TAAs), was investigated. A new mixed catalyst was identified which provides improved cathode performance without the need for the use of a noble metal. This mixed catalyst was tested under load for 1000 hr. in full cell at 160 to 200 C in phosphoric acid H3PO4, and was shown to provide stable performance. The mixed catalyst contains an organometallic to catalyze electroreduction of oxygen to hydrogen peroxide and a metal to catalyze further electroreduction of the hydrogen peroxide to water. Cathodes containing an exemplar mixed catalyst (e.g., Co bisphenyl TAA/Mn) operate at approximately 650 mV vs DHE in 160 C, 85% H3PO4 with oxygen as reactant. In developing this mixed catalyst, a broad spectrum of TAAs were prepared, tested in half-cell and in a rotating ring-disk electrode system. TAAs found to facilitate the production of hydrogen peroxide in electroreduction were shown to be preferred TAAs for use in the mixed catalyst. Manganese (Mn) was identified as a preferred metal because it is capable of catalyzing hydrogen peroxide electroreduction, is lower in cost and is of less strategic importance than platinum, the cathode catalyst normally used in the fuel cell.

  19. Decomposition of Perfluorocompounds on Alumina-Based Catalyst

    SciTech Connect

    Kanno, Shuichi; Tamata, Shin; Kurokawa, Hideaki

    2004-03-31

    The control of the atmospheric release of PFCs (perfluorocompounds) is an important environmental problem worldwide. PFCs are powerful greenhouse gases used by the semiconductor and liquid crystal industries as etching and cleaning agents. We developed a catalyst that decomposes PFCs with only water. Al2O3 was selected from the survey of some single metal-oxide catalysts. Addition of another metal-oxide improved the decomposition ratio and durability. The Al2O3-based catalyst decomposed CF4, C2F6, C3F8, C4F8, NF3 and SF6 by more than 99% at 750 degrees Celsius. Furthermore, our catalyst retained a high decomposition ratio as demonstrated by a continuous run for about 4000 hours at 700-750 degrees Celsius. The influence of chlorine as an impurity with regard to the SF6 decomposition ratio on the catalyst was examined. SF6 was decomposed at more than 99% during 8 hours in the presence of 400 ppm chlorine. Chlorine concentration in the outlet gas was less than TLV. No chlorine compounds were found by X-ray diffraction analysis of the used catalyst. That is, the hydrogenation of chlorine did not inhibit the surface catalytic reaction for PFC. Also, CF4 was decomposed at the condition of 1.4% of high concentration. The conversion remained higher than 99% throughout during a durability test. Furthermore, we investigated a large-scale decomposition system in the paper.

  20. Investigation of Mixed Oxide Catalysts for NO Oxidation

    SciTech Connect

    Szanyi, Janos; Karim, Ayman M.; Pederson, Larry R.; Kwak, Ja Hun; Mei, Donghai; Tran, Diana N.; Herling, Darrell R.; Muntean, George G.; Peden, Charles HF; Howden, Ken; Qi, Gongshin; Li, Wei

    2014-12-09

    The oxidation of engine-generated NO to NO2 is an important step in the reduction of NOx in lean engine exhaust because NO2 is required for the performance of the LNT technology [2], and it enhances the activities of ammonia selective catalytic reduction (SCR) catalysts [1]. In particular, for SCR catalysts an NO:NO2 ratio of 1:1 is most effective for NOx reduction, whereas for LNT catalysts, NO must be oxidized to NO2 before adsorption on the storage components. However, NO2 typically constitutes less than 10% of NOx in lean exhaust, so catalytic oxidation of NO is essential. Platinum has been found to be especially active for NO oxidation, and is widely used in DOC and LNT catalysts. However, because of the high cost and poor thermal durability of Pt-based catalysts, there is substantial interest in the development of alternatives. The objective of this project, in collaboration with partner General Motors, is to develop mixed metal oxide catalysts for NO oxidation, enabling lower precious metal usage in emission control systems. [1] M. Koebel, G. Madia, and M. Elsener, Catalysis Today 73, 239 (2002). [2] C. H. Kim, G. S. Qi, K. Dahlberg, and W. Li, Science 327, 1624 (2010).

  1. Structural Evolution of a Recoverable Rhodium Hydrogenation Catalyst

    SciTech Connect

    Shaw, Wendy J.; Chen, Yongsheng; Fulton, John L.; Linehan, John C.; Gutowska, Anna; Bitterwolf, Thomas E.

    2008-06-01

    N-isopropylacrylamide was utilized as a ligand to affect recoverability into a rhodium hydrogenation catalyst. The catalyst ligand structure was characterized in situ using NMR, XAFS and IR. Model compounds including glycine, cysteamine and methionine methyl ester were also investigated to aid in the interpretation. The investigation revealed a ligand switch from RNH2 to RSR’ when the catalyst is placed in water as opposed to organic solvents. The catalyst continued to transform with time, creating Rh clusters of up to 4 rhodium atoms, with no Rh metal detected. Over the time and solvents investigated, the catalyst ligands evolve from 1-Cl, 1-NH2, and 2-CO’s to 3-Rh, 1-RSR’ and 1-CO. Upon introduction of the alkene for hydrogenation catalysis, the Rh cluster is lost, favoring instead the interaction with the reactant. The kinetics of the hydrogenation reaction were measured using a novel high pressure flow through NMR system and the catalyst was found to have a TOF of 3000/hr at 25 ºC. This work was supported by the Laboratory Directed Research and Development Program at the Pacific Northwest National Laboratory operated by Battelle for the U.S. Department of Energy.

  2. Lignin Depolymerization with Nitrate-Intercalated Hydrotalcite Catalysts

    SciTech Connect

    Kruger, Jacob S.; Cleveland, Nicholas S.; Zhang, Shuting; Katahira, Rui; Black, Brenna A.; Chupka, Gina M.; Lammens, Tijs; Hamilton, Phillip G.; Biddy, Mary J.; Beckham, Gregg T.

    2016-01-13

    Hydrotalcites (HTCs) exhibit multiple adjustable parameters to tune catalytic activity, including interlayer anion composition, metal hydroxide layer composition, and catalyst preparation methods. Here in this paper, we report the influence of several of these parameters on β-O-4 bond scission in a lignin model dimer, 2-phenoxy-1-phenethanol (PE), to yield phenol and acetophenone. We find that the presence of both basic and NO3– anions in the interlayer increases the catalyst activity by 2–3-fold. In contrast, other anions or transition metals do not enhance catalytic activity in comparison to blank HTC. The catalyst is not active for C–C bond cleavage on lignin model dimers and has no effect on dimers without an α-OH group. Most importantly, the catalyst is highly active in the depolymerization of two process-relevant lignin substrates, producing a significant amount of low-molecular-weight aromatic species. The catalyst can be recycled until the NO3– anions are depleted, after which the activity can be restored by replenishing the NO3– reservoir and regenerating the hydrated HTC structure. These results demonstrate a route to selective lignin depolymerization in a heterogeneous system with an inexpensive, earth-abundant, commercially relevant, and easily regenerated catalyst.

  3. Lignin Depolymerization with Nitrate-Intercalated Hydrotalcite Catalysts

    DOE PAGES

    Kruger, Jacob S.; Cleveland, Nicholas S.; Zhang, Shuting; ...

    2016-01-13

    Hydrotalcites (HTCs) exhibit multiple adjustable parameters to tune catalytic activity, including interlayer anion composition, metal hydroxide layer composition, and catalyst preparation methods. Here in this paper, we report the influence of several of these parameters on β-O-4 bond scission in a lignin model dimer, 2-phenoxy-1-phenethanol (PE), to yield phenol and acetophenone. We find that the presence of both basic and NO3– anions in the interlayer increases the catalyst activity by 2–3-fold. In contrast, other anions or transition metals do not enhance catalytic activity in comparison to blank HTC. The catalyst is not active for C–C bond cleavage on lignin modelmore » dimers and has no effect on dimers without an α-OH group. Most importantly, the catalyst is highly active in the depolymerization of two process-relevant lignin substrates, producing a significant amount of low-molecular-weight aromatic species. The catalyst can be recycled until the NO3– anions are depleted, after which the activity can be restored by replenishing the NO3– reservoir and regenerating the hydrated HTC structure. These results demonstrate a route to selective lignin depolymerization in a heterogeneous system with an inexpensive, earth-abundant, commercially relevant, and easily regenerated catalyst.« less

  4. Separately supported polymetallic reforming catalyst

    SciTech Connect

    Kresge, C. T.; Krishnamurthy, S.; McHale, W. D.

    1985-01-15

    There is provided, in accordance with the present invention, a catalyst composition made up of a mixture of two components, one component comprising a minor proportion of platinum and rhenium on a support and the second component comprising a minor proportion of iridium and rhenium on a separate support. A process for reforming a charge stock, such as naphtha, utilizing such catalyst is also provided.

  5. Catalyst for carbon monoxide oxidation

    NASA Technical Reports Server (NTRS)

    Upchurch, Billy T. (Inventor); Miller, Irvin M. (Inventor); Brown, David R. (Inventor); Davis, Patricia P. (Inventor); Schryer, David R. (Inventor); Brown, Kenneth G. (Inventor); Vannorman, John D. (Inventor)

    1991-01-01

    A catalyst for the combination of CO and O2 to form CO2 which includes a platinum group metal, e.g., platinum; a reducible metal oxide having mulitple valence states, e.g., SnO2; and a compound which can bind water to its structure, e.g., silica gel. This catalyst is ideally suited for application to high powered, pulsed, CO2 lasers operating in a sealed or closed cycle condition.

  6. Catalyst for carbon monoxide oxidation

    NASA Technical Reports Server (NTRS)

    Upchurch, Billy T. (Inventor); Miller, Irvin M. (Inventor); Brown, David R. (Inventor); Davis, Patricia (Inventor); Schryer, David R. (Inventor); Brown, Kenneth G. (Inventor); Vannorman, John D. (Inventor)

    1990-01-01

    A catalyst is disclosed for the combination of CO and O2 to form CO2, which includes a platinum group metal (e.g., platinum); a reducable metal oxide having multiple valence states (e.g., SnO2); and a compound which can bind water to its structure (e.g., silica gel). This catalyst is ideally suited for application to high-powered pulsed, CO2 lasers operating in a sealed or closed-cycle condition.

  7. Clay complexes support HDS catalyst.

    SciTech Connect

    Marshall, C. L.; Carrado, K.; Chemical Engineering

    2000-01-01

    Hydroprocessing represents a crucial component of petroleum refining operations both in terms of environmental and economic considerations. Regulations concerning maximum amount of sulfur content of gasoline and emissions of sulfur-oxide compounds upon combustion are becoming more and more stringent. One 1994-2000 focus of Argonne National Laboratory (ANL) has been the development of catalysts for hydrodesulfurization (HDS). Typical HDS catalysts are comprised of Co-Mo sulfides or Ni-Mo sulfides on an alumina support. Modification of the pore structure of the support has generated great attention among researchers. Most desulfurization test reactions have used dibenzothiophene (DBT) as the model compound to test various configurations of support material with Co-Mo-S and Ni-Mo-S catalysts. In this testing, the desired product would be biphenyl and hydrogen sulfide (H{sub 2}S). A competing reaction creates cyclohexylbenzene by saturating one aromatic ring prior to desulfurization. Ring saturation requires more costly hydrogen and is not desirable. Fortunately, a more effective catalyst for adding hydrogen at the sulfur site with hydrogenating the aromatic rings has been found. However, this has only been tested on DBT. HDS uses various types of catalysts to add hydrogen to reduce unwanted sulfur compounds. Typically this requires expensive, high-pressure, high-temperature equipment to produce the environmentally friendly low-sulfur fuels. ANL scientists identified several new desulfurization catalysts with improved HDS activity and selectivity. From these new catalysts, it may be possible to achieve HDS processing at lower temperature and pressure. The catalysts used for HDS at ANL are various clay complexes. Natural clays have a history of use in the hydroprocessing industry since they are abundant and inexpensive. ANL's approach is to create synthetic organo-clay complexes (SOCC). An advantage of SOCCs is that the pore size and distribution can be controlled by

  8. Low Temperature Catalyst for NH3 Removal

    NASA Technical Reports Server (NTRS)

    Monje, Oscar; Melendez, Orlando

    2013-01-01

    Air revitalization technologies maintain a safe atmosphere inside spacecraft by the removal of C02, ammonia (NH3), and trace contaminants. NH3 onboard the International Space Station (ISS) is produced by crew metabolism, payloads, or during an accidental release of thermal control refrigerant. Currently, the ISS relies on removing NH3 via humidity condensate and the crew wears hooded respirators during emergencies. A different approach to cabin NH3 removal is to use selective catalytic oxidation (SCO), which builds on thermal catalytic oxidation concepts that could be incorporated into the existing TCCS process equipment architecture on ISS. A low temperature platinum-based catalyst (LTP-Catalyst) developed at KSC was used for converting NH3 to H20 and N2 gas by SCO. The challenge of implementing SCO is to reduce formation of undesirable byproducts like NOx (N20 and NO). Gas mixture analysis was conducted using FTIR spectrometry in the Regenerable VOC Control System (RVCS) Testbed. The RVCS was modified by adding a 66 L semi-sealed chamber, and a custom NH3 generator. The effect of temperature on NH3 removal using the LTP-Catalyst was examined. A suitable temperature was found where NH3 removal did not produce toxic NO, (NO, N02) and N20 formation was reduced.

  9. Mechanistic insight into sonochemical biodiesel synthesis using heterogeneous base catalyst.

    PubMed

    Choudhury, Hanif A; Chakma, Sankar; Moholkar, Vijayanand S

    2014-01-01

    The beneficial effect of ultrasound on transesterification reaction is well known. Heterogeneous (or solid) catalysts for biodiesel synthesis have merit that they do not contaminate the byproduct of glycerol. In this paper, we have attempted to identify the mechanistic features of ultrasound-enhanced biodiesel synthesis with the base-catalyst of CaO. A statistical design of experiments (Box-Behnken) was used to identify the influence of temperature, alcohol to oil molar ratio and catalyst loading on transesterification yield. The optimum values of these parameters for the highest yield were identified through Response Surface Method (with a quadratic model) and ANOVA. These values are: temperature=62 °C, molar ratio=10:1 and catalyst loading=6 wt.%. The activation energy was determined as 82.3 kJ/mol, which is higher than that for homogeneous catalyzed system (for both acidic and basic catalyst). The experimental results have been analyzed vis-à-vis simulations of cavitation bubble dynamics. Due to 3-phase heterogeneity of the system, the yield was dominated by intrinsic kinetics, and the optimum temperature for the highest yield was close to boiling point of methanol. At this temperature, the influence of cavitation bubbles (in terms of both sonochemical and sonophysical effect) is negligible, and ultrasonic micro-streaming provided necessary convection in the system. The influence of all parameters on the reaction system was found to be strongly inter-dependent.

  10. Light Absorbers and Catalysts for Solar to Fuel Conversion

    NASA Astrophysics Data System (ADS)

    Kornienko, Nikolay I.

    Increasing fossil fuel consumption and the resulting consequences to the environment has propelled research into means of utilizing alternative, clean energy sources. Solar power is among the most promising of renewable energy sources but must be converted into an energy dense medium such as chemical bonds to render it useful for transport and energy storage. Photoelectrochemistry (PEC), the splitting of water into oxygen and hydrogen fuel or reducing CO 2 to hydrocarbon fuels via sunlight is a promising approach towards this goal. Photoelectrochemical systems are comprised of several components, including light absorbers and catalysts. These parts must all synergistically function in a working device. Therefore, the continual development of each component is crucial for the overall goal. For PEC systems to be practical for large scale use, the must be efficient, stable, and composed of cost effective components. To this end, my work focused on the development of light absorbing and catalyst components of PEC solar to fuel converting systems. In the direction of light absorbers, I focused of utilizing Indium Phosphide (InP) nanowires (NWs) as photocathodes. I first developed synthetic techniques for InP NW solution phase and vapor phase growth. Next, I developed light absorbing photocathodes from my InP NWs towards PEC water splitting cells. I studied cobalt sulfide (CoSx) as an earth abundant catalyst for the reductive hydrogen evolution half reaction. Using in situ spectroscopic techniques, I elucidated the active structure of this catalyst and offered clues to its high activity. In addition to hydrogen evolution catalysts, I established a new generation of earth abundant catalysts for CO2 reduction to CO fuel/chemical feedstock. I first worked with molecularly tunable homogeneous catalysts that exhibited high selectivity for CO2 reduction in non-aqueous media. Next, in order to retain molecular tunability while achieving stability and efficiency in aqueous

  11. Electrically heated particulate filter using catalyst striping

    DOEpatents

    Gonze, Eugene V; Paratore, Jr., Michael J; Ament, Frank

    2013-07-16

    An exhaust system that processes exhaust generated by an engine is provided. The system generally includes a particulate filter (PF) that filters particulates from the exhaust wherein an upstream end of the PF receives exhaust from the engine. A grid of electrically resistive material is applied to an exterior upstream surface of the PF and selectively heats exhaust passing through the grid to initiate combustion of particulates within the PF. A catalyst coating is applied to the PF that increases a temperature of the combustion of the particulates within the PF.

  12. Selective catalyst reduction light-off strategy

    DOEpatents

    Gonze, Eugene V [Pinckney, MI

    2011-10-18

    An emissions control system includes a temperature determination module and an emissions control module. The temperature determination module determines a first temperature of a heater element of a diesel particulate filter (DPF) assembly in an exhaust system and determines a second temperature of a catalyst of the DPF assembly. The emissions control module selectively activates the heater element, selectively initiates a predefined combustion process in an engine based upon the first temperature, and selectively starts a reductant injection process based upon the second temperature.

  13. Intermediate Ethanol Blends Catalyst Durability Program

    SciTech Connect

    West, Brian H; Sluder, Scott; Knoll, Keith; Orban, John; Feng, Jingyu

    2012-02-01

    In the summer of 2007, the U.S. Department of Energy (DOE) initiated a test program to evaluate the potential impacts of intermediate ethanol blends (also known as mid-level blends) on legacy vehicles and other engines. The purpose of the test program was to develop information important to assessing the viability of using intermediate blends as a contributor to meeting national goals for the use of renewable fuels. Through a wide range of experimental activities, DOE is evaluating the effects of E15 and E20 - gasoline blended with 15% and 20% ethanol - on tailpipe and evaporative emissions, catalyst and engine durability, vehicle driveability, engine operability, and vehicle and engine materials. This report provides the results of the catalyst durability study, a substantial part of the overall test program. Results from additional projects will be reported separately. The principal purpose of the catalyst durability study was to investigate the effects of adding up to 20% ethanol to gasoline on the durability of catalysts and other aspects of the emissions control systems of vehicles. Section 1 provides further information about the purpose and context of the study. Section 2 describes the experimental approach for the test program, including vehicle selection, aging and emissions test cycle, fuel selection, and data handling and analysis. Section 3 summarizes the effects of the ethanol blends on emissions and fuel economy of the test vehicles. Section 4 summarizes notable unscheduled maintenance and testing issues experienced during the program. The appendixes provide additional detail about the statistical models used in the analysis, detailed statistical analyses, and detailed vehicle specifications.

  14. The innovation catalysts.

    PubMed

    Martin, Roger L

    2011-06-01

    A few years ago the software development company Intuit realized that it needed a new approach to galvanizing customers. The company's Net Promoter Score was faltering, and customer recommendations of new products were especially disappointing. Intuit decided to hold a two-day, off-site meeting for the company's top 300 managers with a focus on the role of design in innovation. One of the days was dedicated to a program called Design for Delight. The centerpiece of the day was a PowerPoint presentation by Intuit founder Scott Cook, who realized midway through that he was no Steve Jobs: The managers listened dutifully, but there was little energy in the room. By contrast, a subsequent exercise in which the participants worked through a design challenge by creating prototypes, getting feedback, iterating, and refining, had them mesmerized. The eventual result was the creation of a team of nine design-thinking coaches--"innovation catalysts"--from across Intuit who were made available to help any work group create prototypes, run experiments, and learn from customers. The process includes a "painstorm" (to determine the customer's greatest pain point), a "soljam" (to generate and then winnow possible solutions), and a "code-jam" (to write code "good enough" to take to customers within two weeks). Design for Delight has enabled employees throughout Intuit to move from satisfying customers to delighting them.

  15. Evaluation of different catalysts and development of a new catalyst for the reduction of CO2 to graphite

    NASA Astrophysics Data System (ADS)

    Tschekalinskij, Alexander; Schindler, Matthias; Kretschmer, Wolfgang

    2016-02-01

    We present an evaluation of different catalysts, methods and parameters for the catalytic reduction of CO2 for 14C-AMS graphite targets for radiocarbon measurement at the Physical Institute of the University Erlangen-Nuremberg in Germany. Currently 10 μm iron powder is used as a catalyst to reduce carbon dioxide to graphite following our standard protocol. An optimal catalyst should provide a short reduction time, no additional fractionation effects, a good reduction yield, lack sintering and should not contain any amounts of both "dead" and "modern" carbon. Seven purchasable catalysts have been evaluated regarding this criteria. Further, the method using zinc and titanium hydride instead of hydrogen gas and the water-trap has been applied to our system and the effect of the water-trap temperature on the reduction time has been tested. A self-made catalyst was produced using aluminum oxide impregnated with iron nitrate. The results of this study indicate three good catalysts and show the success of the applied methods on standard samples like Ox II and Alfa graphite.

  16. Remaining activity determination of the resid desulfurization catalyst in a commerical plant

    SciTech Connect

    Yung-Ji Tarng; Sheng-Yang Ju

    1996-12-31

    The objective of this paper is to present a method to determine the remaining catalyst activity of the resid desulfurization plant. Using the daily available operating data, we can establish a performance curve which is a temperature versus days on stream curve. By the use of the performance curve, we can in situ predict how much the catalyst life remains. With the knowledge of the catalyst life remaining, plant engineers are able to control the operating conditions to meet the specified run length of the catalyst suggested by the catalyst venders and refinery planning department. There are five heavy oil desulfurization (RDS) plants in Chinese Petroleum Corporation (CPC) to produce the low sulfur fuel oil and low metal content feed stocks for the downstream processes. In general four or five reactors are connected in series for the reacting system and catalysts of various types are loaded in each reactor. 3 refs., 1 fig., 4 tabs.

  17. Biphasic catalysis using amphiphilic polyphenols-chelated noble metals as highly active and selective catalysts

    PubMed Central

    Mao, Hui; Yu, Hong; Chen, Jing; Liao, Xuepin

    2013-01-01

    In the field of catalysis, it is highly desired to develop novel catalysts that combine the advantages of both homogeneous and heterogeneous catalysts. Here we disclose that the use of plant pholyphenol as amphiphilic large molecule ligand/stabilizer allows for the preparation of noble metal complex and noble metal nanoparticle catalysts. These catalysts are found to be highly selective and active in aqueous-organic biphasic catalysis of cinnamaldehyde and quinoline, and can be reused at least 3 times without significant loss of activity. Moreover, the catalytic activity and reusability of the catalysts can be rationally controlled by simply adjusting the content of polyphenols in the catalysts. Our strategy may be extended to design a wide range of aqueous-organic biphasic catalysis system. PMID:23863916

  18. Molecular co-catalyst accelerating hole transfer for enhanced photocatalytic H2 evolution

    PubMed Central

    Bi, Wentuan; Li, Xiaogang; Zhang, Lei; Jin, Tao; Zhang, Lidong; Zhang, Qun; Luo, Yi; Wu, Changzheng; Xie, Yi

    2015-01-01

    In artificial photocatalysis, sluggish kinetics of hole transfer and the resulting high-charge recombination rate have been the Achilles' heel of photocatalytic conversion efficiency. Here we demonstrate water-soluble molecules as co-catalysts to accelerate hole transfer for improved photocatalytic H2 evolution activity. Trifluoroacetic acid (TFA), by virtue of its reversible redox couple TFA·/TFA−, serves as a homogeneous co-catalyst that not only maximizes the contact areas between co-catalysts and reactants but also greatly promotes hole transfer. Thus K4Nb6O17 nanosheet catalysts achieve drastically increased photocatalytic H2 production rate in the presence of TFA, up to 32 times with respect to the blank experiment. The molecular co-catalyst represents a new, simple and highly effective approach to suppress recombination of photogenerated charges, and has provided fertile new ground for creating high-efficiency photosynthesis systems, avoiding use of noble-metal co-catalysts. PMID:26486863

  19. Low-temperature CO oxidation over a ternary oxide catalyst with high resistance to hydrocarbon inhibition

    DOE PAGES

    Binder, Andrew J.; Toops, Todd J.; Unocic, Raymond R.; ...

    2015-09-11

    Platinum group metal (PGM) catalysts are the current standard for control of pollutants in automotive exhaust streams. Aside from their high cost, PGM catalysts struggle with CO oxidation at low temperatures (<200 °C) due to inhibition by hydrocarbons in exhaust streams. Here we present a ternary mixed oxide catalyst composed of copper oxide, cobalt oxide, and ceria (dubbed CCC) that outperforms synthesized and commercial PGM catalysts for CO oxidation in simulated exhaust streams while showing no signs of inhibition by propene. Diffuse reflectance IR (DRIFTS) and light-off data both indicate low interaction between propene and the CO oxidation active sitemore » on this catalyst, and a separation of adsorption sites is proposed as the cause of this inhibition resistance. In conclusion, this catalyst shows great potential as a low-cost component for low temperature exhaust streams that are expected to be a characteristic of future automotive systems.« less

  20. Molecular co-catalyst accelerating hole transfer for enhanced photocatalytic H2 evolution

    NASA Astrophysics Data System (ADS)

    Bi, Wentuan; Li, Xiaogang; Zhang, Lei; Jin, Tao; Zhang, Lidong; Zhang, Qun; Luo, Yi; Wu, Changzheng; Xie, Yi

    2015-10-01

    In artificial photocatalysis, sluggish kinetics of hole transfer and the resulting high-charge recombination rate have been the Achilles' heel of photocatalytic conversion efficiency. Here we demonstrate water-soluble molecules as co-catalysts to accelerate hole transfer for improved photocatalytic H2 evolution activity. Trifluoroacetic acid (TFA), by virtue of its reversible redox couple TFA./TFA-, serves as a homogeneous co-catalyst that not only maximizes the contact areas between co-catalysts and reactants but also greatly promotes hole transfer. Thus K4Nb6O17 nanosheet catalysts achieve drastically increased photocatalytic H2 production rate in the presence of TFA, up to 32 times with respect to the blank experiment. The molecular co-catalyst represents a new, simple and highly effective approach to suppress recombination of photogenerated charges, and has provided fertile new ground for creating high-efficiency photosynthesis systems, avoiding use of noble-metal co-catalysts.

  1. Low-temperature CO oxidation over a ternary oxide catalyst with high resistance to hydrocarbon inhibition

    SciTech Connect

    Binder, Andrew J.; Toops, Todd J.; Unocic, Raymond R.; Parks, II, James E.; Dai, Sheng

    2015-09-11

    Platinum group metal (PGM) catalysts are the current standard for control of pollutants in automotive exhaust streams. Aside from their high cost, PGM catalysts struggle with CO oxidation at low temperatures (<200 °C) due to inhibition by hydrocarbons in exhaust streams. Here we present a ternary mixed oxide catalyst composed of copper oxide, cobalt oxide, and ceria (dubbed CCC) that outperforms synthesized and commercial PGM catalysts for CO oxidation in simulated exhaust streams while showing no signs of inhibition by propene. Diffuse reflectance IR (DRIFTS) and light-off data both indicate low interaction between propene and the CO oxidation active site on this catalyst, and a separation of adsorption sites is proposed as the cause of this inhibition resistance. In conclusion, this catalyst shows great potential as a low-cost component for low temperature exhaust streams that are expected to be a characteristic of future automotive systems.

  2. Metal-Organic Framework Photosensitized TiO2 Co-catalyst: A Facile Strategy to Achieve a High Efficiency Photocatalytic System.

    PubMed

    Xie, Ming-Hua; Shao, Rong; Xi, Xin-Guo; Hou, Gui-Hua; Guan, Rong-Feng; Dong, Peng-Yu; Zhang, Qin-Fang; Yang, Xiu-Li

    2017-03-17

    A 3D metal-organic framework (ADA-Cd=[Cd2 L2 (DMF)2 ]⋅3 H2 O where H2 L is (2E,2'E)-3,3'-(anthracene-9,10-diyl)diacrylic acid) constructed from diacrylate substituted anthracene, sharing structural characteristics with some frequently employed anthraquinone-type dye sensitizers, was introduced as an effective sensitizer for anatase TiO2 to achieve enhanced visible light photocatalytic performance. A facile mechanical mixing procedure was adopted to prepare the co-catalyst denoted as ADA-Cd/TiO2 , which showed enhanced photodegradation ability, as well as sustainability, towards several dyes under visible light irradiation. Mechanistic studies revealed that ADA-Cd acted as the antenna to harvest visible light energy, generating excited electrons, which were injected to the conduction band (CB) of TiO2 , facilitating the separation efficiency of charge carriers. As suggested by the results of control experiments, combined with the corresponding redox potential of possible oxidative species, (.) O2(-) , generated from the oxygen of ambient air at the CB of TiO2 was believed to play a dominant role over (.) OH and h(+) . UV/Vis and photoluminescence technologies were adopted to monitor the generation of (.) O2(-) and (.) OH, respectively. This work presents a facile strategy to achieve a visible light photocatalyst with enhanced catalytic activity and sustainability; the simplicity, efficiency, and stability of this strategy may provide a promising way to achieve environmental remediation.

  3. Nanofiltration of rhodium tris(triphenylphosphine) catalyst in ethyl acetate solution

    NASA Astrophysics Data System (ADS)

    Shaharun, Maizatul S.; Mustafa, Ahmad K.; Taha, Mohd F.

    2012-09-01

    Solvent resistant nanofiltration (SRNF) using polymer membranes has recently received enhanced attention due to the search for cleaner and more energy-efficient technologies. The large size of the rhodium tris(triphenylphosphine) [HRh(CO)(PPh3)3] catalyst (>400 Da) - relative to other components of the hydroformylation reaction provides the opportunity for a membrane separation based on retention of the catalyst species while permeating the solvent. The compatibility of the solvent-polyimide membrane (DuraMem{trade mark, serif} 200 and DuraMem{trade mark, serif} 500) combinations was assessed in terms of the membrane stability in solvent plus non-zero solvent flux at 2.0 MPa. Good HRh(CO)(PPh3)3 rejection (>0.95) and solvent fluxes of 9.9 L/m2ṡh1 at 2.0 MPa were obtained in the catalyst-ethyl acetate-DuraMem 500 system. The effect of pressure and catalyst concentration on the solvent flux and catalyst rejection was conducted on the catalyst-ethyl acetate-membrane systems. Increasing pressure substantially improved both solvent flux and catalyst rejection, while increasing catalyst concentration was found to be beneficial in terms of substantial increases in catalyst rejection without significantly affecting solvent flux.

  4. Pretreatment of CO oxidation catalysts

    NASA Technical Reports Server (NTRS)

    Vannorman, John D.

    1988-01-01

    CO oxidation catalysts with high activity in the range of 25 C to 100 C are important for long-life, closed-cycle operation of pulsed carbon dioxide 2 lasers. A reductive pretreatment with either CO or H sub 2 was shown to significantly enhance the activity of a commerically-available platinum on tin (IV) oxide (Pt/SnO2) catalyst relative to an oxidative or inert pretreatment or no pretreatment. Pretreatment at temperatures of 175 C and above caused an initial dip in observed CO or O sub 2 loss or CO sub 2 formation in a test gas mixture of 1 percent CO and 0.5 percent O sub 2 in a He gas matrix before a steady-state yield was obtained. This dip was found to be caused by dehydration of the surface of the catalyst and was readily eliminated by humidifying the catalyst or the test gas mixture. It was also found that too much moisture resulted in a lower overall yield of CO sub 2. Under similar conditions, it is hypothesized that the effect of the humidification is to increase the concentration of OH groups on the surface of the catalyst. The effect of having high concentration of CO sub 2 in the test gas mixture upon the loss of CO and O sub 2 as well as the effect of periods of relaxation of the catalyst under non-test gas conditions was studied. The purpose of these studies was to gain an insight into the mechanism of CO oxidation on this type of catalyst.

  5. Catalyst for coal liquefaction process

    DOEpatents

    Huibers, Derk T. A.; Kang, Chia-Chen C.

    1984-01-01

    An improved catalyst for a coal liquefaction process; e.g., the H-Coal Process, for converting coal into liquid fuels, and where the conversion is carried out in an ebullated-catalyst-bed reactor wherein the coal contacts catalyst particles and is converted, in addition to liquid fuels, to gas and residual oil which includes preasphaltenes and asphaltenes. The improvement comprises a catalyst selected from the group consisting of the oxides of nickel molybdenum, cobalt molybdenum, cobalt tungsten, and nickel tungsten on a carrier of alumina, silica, or a combination of alumina and silica. The catalyst has a total pore volume of about 0.500 to about 0.900 cc/g and the pore volume comprises micropores, intermediate pores and macropores, the surface of the intermediate pores being sufficiently large to convert the preasphaltenes to asphaltenes and lighter molecules. The conversion of the asphaltenes takes place on the surface of micropores. The macropores are for metal deposition and to prevent catalyst agglomeration. The micropores have diameters between about 50 and about 200 angstroms (.ANG.) and comprise from about 50 to about 80% of the pore volume, whereas the intermediate pores have diameters between about 200 and 2000 angstroms (.ANG.) and comprise from about 10 to about 25% of the pore volume, and the macropores have diameters between about 2000 and about 10,000 angstroms (.ANG.) and comprise from about 10 to about 25% of the pore volume. The catalysts are further improved where they contain promoters. Such promoters include the oxides of vanadium, tungsten, copper, iron and barium, tin chloride, tin fluoride and rare earth metals.

  6. Static and dynamic structural characterization of nanomaterial catalysts

    NASA Astrophysics Data System (ADS)

    Masiel, Daniel Joseph

    Heterogeneous catalysts systems are pervasive in industry, technology and academia. These systems often involve nanostructured transition metal particles that have crucial interfaces with either their supports or solid products. Understanding the nature of these interfaces as well as the structure of the catalysts and support materials themselves is crucial for the advancement of catalysis in general. Recent developments in the field of transmission electron microscopy (TEM) including dynamic transmission electron microscopy (DTEM), electron tomography, and in situ techniques stand poised to provide fresh insight into nanostructured catalyst systems. Several electron microscopy techniques are applied in this study to elucidate the mechanism of silica nanocoil growth and to discern the role of the support material and catalyst size in carbon dioxide and steam reforming of methane. The growth of silica nanocoils by faceted cobalt nanoparticles is a process that was initially believed to take place via a vapor-liquid-solid growth mechanism similar to other nanowire growth techniques. The extensive TEM work described here suggests that the process may instead occur via transport of silicate and silica species over the nanoparticle surface. Electron tomography studies of the interface between the catalyst particles and the wire indicate that they grow from edges between facets. Studies on reduction of the Co 3O4 nanoparticle precursors to the faceted pure cobalt catalysts were carried out using DTEM and in situ heating. Supported catalyst systems for methane reforming were studied using dark field scanning TEM to better understand sintering effects and the increased activity of Ni/Co catalysts supported by carbon nanotubes. Several novel electron microscopy techniques are described including annular dark field DTEM and a metaheuristic algorithm for solving the phase problem of coherent diffractive imaging. By inserting an annular dark field aperture into the back focal

  7. A pentanuclear iron catalyst designed for water oxidation.

    PubMed

    Okamura, Masaya; Kondo, Mio; Kuga, Reiko; Kurashige, Yuki; Yanai, Takeshi; Hayami, Shinya; Praneeth, Vijayendran K K; Yoshida, Masaki; Yoneda, Ko; Kawata, Satoshi; Masaoka, Shigeyuki

    2016-02-25

    Although the oxidation of water is efficiently catalysed by the oxygen-evolving complex in photosystem II (refs 1 and 2), it remains one of the main bottlenecks when aiming for synthetic chemical fuel production powered by sunlight or electricity. Consequently, the development of active and stable water oxidation catalysts is crucial, with heterogeneous systems considered more suitable for practical use and their homogeneous counterparts more suitable for targeted, molecular-level design guided by mechanistic understanding. Research into the mechanism of water oxidation has resulted in a range of synthetic molecular catalysts, yet there remains much interest in systems that use abundant, inexpensive and environmentally benign metals such as iron (the most abundant transition metal in the Earth's crust and found in natural and synthetic oxidation catalysts). Water oxidation catalysts based on mononuclear iron complexes have been explored, but they often deactivate rapidly and exhibit relatively low activities. Here we report a pentanuclear iron complex that efficiently and robustly catalyses water oxidation with a turnover frequency of 1,900 per second, which is about three orders of magnitude larger than that of other iron-based catalysts. Electrochemical analysis confirms the redox flexibility of the system, characterized by six different oxidation states between Fe(II)5 and Fe(III)5; the Fe(III)5 state is active for oxidizing water. Quantum chemistry calculations indicate that the presence of adjacent active sites facilitates O-O bond formation with a reaction barrier of less than ten kilocalories per mole. Although the need for a high overpotential and the inability to operate in water-rich solutions limit the practicality of the present system, our findings clearly indicate that efficient water oxidation catalysts based on iron complexes can be created by ensuring that the system has redox flexibility and contains adjacent water-activation sites.

  8. A pentanuclear iron catalyst designed for water oxidation

    NASA Astrophysics Data System (ADS)

    Okamura, Masaya; Kondo, Mio; Kuga, Reiko; Kurashige, Yuki; Yanai, Takeshi; Hayami, Shinya; Praneeth, Vijayendran K. K.; Yoshida, Masaki; Yoneda, Ko; Kawata, Satoshi; Masaoka, Shigeyuki

    2016-02-01

    Although the oxidation of water is efficiently catalysed by the oxygen-evolving complex in photosystem II (refs 1 and 2), it remains one of the main bottlenecks when aiming for synthetic chemical fuel production powered by sunlight or electricity. Consequently, the development of active and stable water oxidation catalysts is crucial, with heterogeneous systems considered more suitable for practical use and their homogeneous counterparts more suitable for targeted, molecular-level design guided by mechanistic understanding. Research into the mechanism of water oxidation has resulted in a range of synthetic molecular catalysts, yet there remains much interest in systems that use abundant, inexpensive and environmentally benign metals such as iron (the most abundant transition metal in the Earth’s crust and found in natural and synthetic oxidation catalysts). Water oxidation catalysts based on mononuclear iron complexes have been explored, but they often deactivate rapidly and exhibit relatively low activities. Here we report a pentanuclear iron complex that efficiently and robustly catalyses water oxidation with a turnover frequency of 1,900 per second, which is about three orders of magnitude larger than that of other iron-based catalysts. Electrochemical analysis confirms the redox flexibility of the system, characterized by six different oxidation states between FeII5 and FeIII5; the FeIII5 state is active for oxidizing water. Quantum chemistry calculations indicate that the presence of adjacent active sites facilitates O-O bond formation with a reaction barrier of less than ten kilocalories per mole. Although the need for a high overpotential and the inability to operate in water-rich solutions limit the practicality of the present system, our findings clearly indicate that efficient water oxidation catalysts based on iron complexes can be created by ensuring that the system has redox flexibility and contains adjacent water-activation sites.

  9. Coking characteristics of reforming catalysts

    SciTech Connect

    Mieville, R.L.

    1986-08-01

    Coking rates were measured for two different ..gamma..-aluminas, each with and without platinum, under near commercial conditions using a gravimetric reactor. Coke on catalyst was characterized by a Temperature-Programmed Oxidation (TPO) technique. With a naphtha feed, coke formed on both aluminas at rates related to the respective population of ..cap alpha..-sites as measured by IR. For the corresponding Pt on alumina catalysts, coke, as measured by TPO, predominantly formed on sites associated with alumina (alumina coke), while coke associated with Pt (Pt coke), was relatively minor. With a n-heptane feed, under the same conditions, coke formation on both aluminas was much less than with the naphtha feed. However, the corresponding Pt on alumina catalysts generated comparatively more coke with a higher proportion associated with Pt. A correspondence between this proportion of Pt coke and the decline in reforming activity was observed. It is postulated that most of the coke produced during naphtha reforming with an active catalyst is formed by a reaction between ..cap alpha..-sites on alumina and certain components in the feed via a polymerization mechanism. This type of coke has minimal effect on the reforming reactivity of the catalyst. However, in n-heptane reforming, about 50% of the coke also results from precursors formed from reactions with Pt. In either case, coke associated with Pt appears to be the probable cause of deactivation. 22 references.

  10. Study of removal of ammonia from urine vapor by dual catalyst

    NASA Technical Reports Server (NTRS)

    Budininkas, P.

    1976-01-01

    The feasibility of ammonia removal from urine vapor by a low temperature dual-catalyst system was investigated. The process is based on the initial catalytic oxidation of ammonia present in urine vapor to nitrogen and nitrous oxide, followed by a catalytic decomposition of the nitrous oxide formed into its elements. The most active catalysts for the oxidation of ammonia and for the decomposition of N2O, identified in screening tests, were then combined into dual catalyst systems and tested to establish their overall efficiencies for the removal of ammonia from artificial gas mixtures. Dual catalyst systems capable of ammonia removal from the artificial gas mixtures were then tested with the actual urine vapor produced by boiling untreated urine. A suitable dual catalyst bed arrangement was found that achieved the removal of ammonia and organic carbon, and recovered water of good quality from urine vapor.

  11. Methods and catalysts for making biodiesel from the transesterification and esterification of unrefined oils

    DOEpatents

    Yan, Shuli [Detroit, MI; Salley, Steven O [Grosse Pointe Park, MI; Ng, K Y. Simon [West Bloomfield, MI

    2012-04-24

    A method of forming a biodiesel product and a heterogeneous catalyst system used to form said product that has a high tolerance for the presence of water and free fatty acids (FFA) in the oil feedstock is disclosed. This catalyst system may simultaneously catalyze both the esterification of FAA and the transesterification of triglycerides present in the oil feedstock. The catalyst system according to one aspect of the present disclosure represents a class of zinc and lanthanum oxide heterogeneous catalysts that include different ratios of zinc oxide to lanthanum oxides (Zn:La ratio) ranging from about 10:0 to 0:10. The Zn:La ratio in the catalyst is believed to have an effect on the number and reactivity of Lewis acid and base sites, as well as the transesterification of glycerides, the esterification of fatty acids, and the hydrolysis of glycerides and biodiesel.

  12. DEVELOPMENT OF A NOVEL CATALYST FOR NO DECOMPOSITION

    SciTech Connect

    Ates Akyurtlu; Jale F. Akyurtlu

    2004-05-01

    } catalysts having different noble metal concentrations and pretreated under different conditions. It is also proposed to perform NO decomposition tests in a laboratory-size packed-bed reactor to obtain long-term deactivation data. In the current reporting period first the GC-MS system was calibrated. Then the TPD runs for the 15% Pt/SnO{sub 2} catalyst after treatment with NO and subsequent treatments with NO and O{sub 2} were done. For these runs the catalyst was pretreated with dry helium for 2 hours at 40 C.

  13. Bound zeolite catalyst and process for using the catalyst

    SciTech Connect

    Kao, J.L.; Poeppelmeier, K.R.; Funk, W.G.; Steger, J.J.; Fung, S.C.; Cross, V.R.

    1987-03-10

    A process is described for reforming naphtha. The process comprises (a) contacting the naphtha in the presence of hydrogen at elevated temperatures with a catalyst comprising a binder, a type L zeolite containing exchangeable cations of which at least 75% are selected from the group consisting of lithium, sodium, potassium, rubidium, cesium, calcium and barium, at least one Group VIII noble metal, the particles of which are well dispersed over the surface of the catalyst and at least 90% of the noble metal associated with the zeolite is in the form of particles having a diameter of less than about 7 A; and (b) recovering reformed product.

  14. Au-Based Catalysts: Electrochemical Characterization for Structural Insights.

    PubMed

    Pifferi, Valentina; Chan-Thaw, Carine E; Campisi, Sebastiano; Testolin, Anna; Villa, Alberto; Falciola, Luigi; Prati, Laura

    2016-02-25

    Au-based catalysts are widely used in important processes because of their peculiar characteristics. The catalyst performance depends strongly on the nature and structure of the metal nanoparticles, especially in the case of bimetallic catalysts where synergistic effects between the two metals can be occasionally seen. In this paper, it is shown that electrochemical characterisation (cyclovoltammetry CV and electrochemical impedance spectroscopy EIS) of AuPd systems can be used to determine the presence of an electronic interaction between the two metals, thus providing a strong support in the determination of the nature of the synergy between Au and Pd in the liquid phase oxidation of alcohols. However, it seems likely that the strong difference in the catalytic behavior between the single metals and the bimetallic system is connected not only to the redox behaviour, but also to the energetic balance between the different elementary steps of the reaction.

  15. Regeneration of Hydrotreating and FCC Catalysts

    SciTech Connect

    CM Wai; JG Frye; JL Fulton; LE Bowman; LJ Silva; MA Gerber

    1999-09-30

    Hydrotreating, hydrocracking, and fluid catalytic cracking (FCC) catalysts are important components of petroleum refining processes. Hydrotreating and hydrocracking catalysts are used to improve the yield of high-quality light oil fractions from heavier crude oil and petroleum feedstocks containing high levels of impurities. FCC catalysts improve the yield of higher octane gasoline from crude oil. Residuum hydrotreating and cracking catalysts are susceptible to irreversible deactivation caused by adsorption of sulfur and by metals impurities, such as vanadium and nickel. The gradual buildup of these impurities in a hydrotreating catalyst eventually plugs the pores and deactivates it. Nickel and vanadium adversely affect the behavior of cracking catalysts, reducing product yield and quality. Replacing deactivated catalysts represents a significant cost in petroleum refining. Equally important are the costs and potential liabilities associated with treating and disposing spent catalysts. For example, recent US Environmental Protection Agency rulings have listed spent hydrotreating and hydrorefining catalysts as hazardous wastes. FCC catalysts, though more easily disposed of as road-base or as filler in asphalt and cement, are still an economic concern mainly because of the large volumes of spent catalysts generated. New processes are being considered to increase the useful life of catalysts or for meeting more stringent disposal requirements for spent catalysts containing metals. This report discusses a collaborative effort between Pacific Northwest National Laboratory (PNNL) and Phillips Petroleum, Inc., to identify promising chemical processes for removing metals adhered to spent hydrodesulfurization (HDS, a type of hydrotreating catalyst) and FCC catalysts. This study, conducted by PNNL, was funded by the US Department of Energy's Bartlesville Project Office. Fresh and spent catalysts were provided by Phillips Petroleum. The FCC catalyst was a rare-earth exchanged

  16. Heterogeneous base catalysts for edible palm and non-edible Jatropha-based biodiesel production

    PubMed Central

    2014-01-01

    Background Transesterification catalyzed by solid base catalyst is a brilliant technology for the noble process featuring the fast reaction under mild reacting condition in biodiesel production. Heterogeneous base catalysts are generally more reactive than solid acid catalysts which require extreme operating condition for high conversion and biodiesel yield. In the present study, synthesis of biodiesel was studied by using edible (palm) or non-edible (Jatropha) feedstock catalyzed by heterogeneous base catalysts such as supported alkali metal (NaOH/Al2O3), alkaline-earth metal oxide (MgO, CaO and SrO) and mixed metal oxides catalysts (CaMgO and CaZnO). Results The chemical characteristic, textural properties, basicity profile and leaching test of synthesized catalysts were studied by using X-ray diffraction, BET measurement, TPD-CO2 and ICP-AES analysis, respectively. Transesterification activity of solid base catalysts showed that > 90% of palm biodiesel and > 80% of Jatropha biodiesel yield under 3 wt.% of catalyst, 3 h reaction time, methanol to oil ratio of 15:1 under 65°C. This indicated that other than physicochemical characteristic of catalysts; different types of natural oil greatly influence the catalytic reaction due to the presence of free fatty acids (FFAs). Conclusions Among the solid base catalysts, calcium based mixed metal oxides catalysts with binary metal system (CaMgO and CaZnO) showed capability to maintain the transesterification activity for 3 continuous runs at ~ 80% yield. These catalysts render high durability characteristic in transesterification with low active metal leaching for several cycles. PMID:24812574

  17. Selective methane oxidation over promoted oxide catalysts. Topical report, September 8, 1992--September 7, 1996

    SciTech Connect

    Klier, K.; Herman, R.G.

    1996-12-31

    The objective of this research was to selectively oxidize methane to C{sub 2} hydrocarbons and to oxygenates, in particular formaldehyde and methanol, in high space time yields using air at the oxidant under milder reaction conditions that heretofore employed over industrially practical oxide catalysts. The research carried out under this US DOE-METC contract was divided into the following three tasks: Task 1, maximizing selective methane oxidation to C{sub 2}{sup +} products over promoted SrO/La{sub 2}O{sub 3} catalysts; Task 2, selective methane oxidation to oxygenates; and Task 3, catalyst characterization and optimization. Principal accomplishments include the following: the 1 wt% SO{sub 4}{sup 2{minus}}/SrO/La{sub 2}O{sub 3} promoted catalyst developed here produced over 2 kg of C{sub 2} hydrocarbons/kg catalyst/hr at 550 C; V{sub 2}O{sub 5}/SiO{sub 2} catalysts have been prepared that produce up to 1.5 kg formaldehyde/kg catalyst/hr at 630 C with low CO{sub 2} selectivities; and a novel dual bed catalyst system has been designed and utilized to produce over 100 g methanol/kg catalyst/hr at 600 C with the presence of steam in the reactant mixture.

  18. Growth of Single-Walled Carbon Nanotubes by High Melting Point Metal Oxide Catalysts

    NASA Astrophysics Data System (ADS)

    Qian, Yang; Xiang, Rong; An, Hua; Inoue, Taiki; Chiashi, Shohei; Maruyama, Shigeo

    We report on the growth of single-walled carbon nanotubes (SWNTs) from Co oxide catalysts. The concept is using the relatively lower mobility of metal oxide (than metal) to suppress catalyst aggregation at high temperatures. Compared to the SWNTs grown by pre-reduced catalysts, SWNTs grown from oxidized Co catalysts have shown narrower diameter distribution and smaller average diameter. Different growth parameters are discussed regarding the resulting morphology of SWNTs. Transmission electron microscopy (TEM) investigations reveal the information that Co catalysts are transformed to Co3O4 after reduction-calcination process. X-ray photoelectron spectroscopy (XPS) investigations indicate that Co3O4 has decomposed to CoO before growth at a typical growth temperature (800 ºC) in Ar atmosphere. We propose that CoO has higher melting point than Co and thus is more stable during the growth. Our results indicate that besides the bimetallic catalysts, monometallic catalytic system could also be useful in stabilizing the catalysts to grow chirality-specific SWNTs by transforming the relatively low melting point metal catalysts to high melting point metal oxide catalysts. Yang Qian was supported through ``Global Leader Program for Social Design and Management''.

  19. Catalysts for improved fuel processing

    SciTech Connect

    Borup, R.L.; Inbody, M.A.

    2000-09-01

    This report covers our technical progress on fuel processing catalyst characterization for the specific purpose of hydrogen production for proton-exchange-membrane (PEM) fuel cells. These development efforts support DOE activities in the development of compact, transient capable reformers for on-board hydrogen generation starting from candidate fuels. The long-term objective includes increased durability and lifetime, in addition to smaller volume, improved performance, and other specifications required meeting fuel processor goals. The technical barriers of compact fuel processor size, transient capability, and compact, efficient thermal management all are functions of catalyst performance. Significantly, work at LANL now tests large-scale fuel processors for performance and durability, as influenced by fuels and fuel constituents, and complements that testing with micro-scale catalyst evaluation which is accomplished under well controlled conditions.

  20. Catalyst containing oxygen transport membrane

    DOEpatents

    Lane, Jonathan A.; Wilson, Jamie R.; Christie, Gervase Maxwell; Petigny, Nathalie; Sarantopoulos, Christos

    2017-02-07

    A composite oxygen transport membrane having a dense layer, a porous support layer and an intermediate porous layer located between the dense layer and the porous support layer. Both the dense layer and the intermediate porous layer are formed from an ionic conductive material to conduct oxygen ions and an electrically conductive material to conduct electrons. The porous support layer has a high permeability, high porosity, and a microstructure exhibiting substantially uniform pore size distribution as a result of using PMMA pore forming materials or a bi-modal particle size distribution of the porous support layer materials. Catalyst particles selected to promote oxidation of a combustible substance are located in the intermediate porous layer and in the porous support adjacent to the intermediate porous layer. The catalyst particles can be formed by wicking a solution of catalyst precursors through the porous support toward the intermediate porous layer.

  1. Catalyst containing oxygen transport membrane

    DOEpatents

    Christie, Gervase Maxwell; Wilson, Jamie Robyn; van Hassel, Bart Antonie

    2012-12-04

    A composite oxygen transport membrane having a dense layer, a porous support layer and an intermediate porous layer located between the dense layer and the porous support layer. Both the dense layer and the intermediate porous layer are formed from an ionic conductive material to conduct oxygen ions and an electrically conductive material to conduct electrons. The porous support layer has a high permeability, high porosity, and a high average pore diameter and the intermediate porous layer has a lower permeability and lower pore diameter than the porous support layer. Catalyst particles selected to promote oxidation of a combustible substance are located in the intermediate porous layer and in the porous support adjacent to the intermediate porous layer. The catalyst particles can be formed by wicking a solution of catalyst precursors through the porous support toward the intermediate porous layer.

  2. Templating Routes to Supported Oxide Catalysts by Design

    SciTech Connect

    Notestein, Justin M.

    2016-09-08

    The rational design and understanding of supported oxide catalysts requires at least three advancements, in order of increasing complexity: the ability to quantify the number and nature of active sites in a catalytic material, the ability to place external controls on the number and structure of these active sites, and the ability to assemble these active sites so as to carry out more complex functions in tandem. As part of an individual investigator research program that is integrated with the Northwestern University Institute for Catalysis in Energy Processes (ICEP) as of 2015, significant advances were achieved in these three areas. First, phosphonic acids were utilized in the quantitative assessment of the number of active and geometrically-available sites in MOx-SiO2 catalysts, including nanocrystalline composites, co-condensed materials, and grafted structures, for M=Ti, Zr, Hf, Nb, and Ta. That work built off progress in understanding supported Fe, Cu, and Co oxide catalysts from chelating and/or multinuclear precursors to maximize surface reactivity. Secondly, significant progress was made in the new area of using thin oxide overcoats containing ‘nanocavities’ from organic templates as a method to control the dispersion and thermal stability of subsequently deposited metal nanoparticles or other catalytic domains. Similar methods were used to control surface reactivity in SiO2-Al2O3 acid catalysts and to control reactant selectivity in Al2O3-TiO2 photocatalysts. Finally, knowledge gained from the first two areas has been combined to synthesize a tandem catalyst for hydrotreating reactions and an orthogonal tandem catalyst system where two subsequent reactions in a reaction network are independently controlled by light and heat. Overall, work carried out under this project significantly advanced the knowledge of synthesis-structure-function relationships in supported

  3. Productions of sunflower oil biodiesel and used cooking oil through heterogeneous catalysts compared to conventional homogeneous catalysts

    NASA Astrophysics Data System (ADS)

    Gutiérrez-Zapata, C. A.; Blanco Martínez, D.; Collazos, C. A.; Castellanos Acuña, H. E.; Cuervo, J. A.; Fernandez, C. P.

    2017-01-01

    This document compares homogeneous and heterogeneous catalysts used by production of biodiesel of sunflower oil and cooking oil used in frying. For this, NaOH was used as a catalyst homogeneous, and K2CO3 and Na2CO3 supported in gamma-alumina (K2CO3/γ Al2O3 y Na2CO3 /γ-Al2O3) were synthesized as heterogeneous catalysts, which were characterized by X-ray diffraction. The transesterification tests were carried out for the sunflower oil and used cooking oil, in a reflux system, to different molar relations methanol/oil, depending on the type of oil and characterization of the same. The reflux system is performed at a temperature of 55-60°C for one hour. Finally, biofuel was characterized and the yield of the reaction was calculated.

  4. A high yield reverse micelle synthesis of catalysts and catalyst precursors

    SciTech Connect

    Linehan, J.C.; Matson, D.W.; Darab, J.G.

    1995-12-01

    Water-in-oil (w/o) microemulsions containing high ionic strengths in their aqueous cores have been produced by using a stabilizing co-surfactant. These {open_quotes}modified{close_quotes} w/o microemulsions have proven to be effective media in which to synthesize nanophase metal, metal oxide, metal sulfide, and mixed metal containing powders suitable for use as catalysts or catalyst precursors. Up to 10 grams of nanocrystalline powder can be produced per liter of the modified microemulsion because of the high reactant concentrations that can be attained using these systems. The nanocrystalline powders produced have been characterized by XRD, SEM, and TEM, as well as by other techniques where appropriate.

  5. Catalysts for carbon and coal gasification

    DOEpatents

    McKee, Douglas W.; Spiro, Clifford L.; Kosky, Philip G.

    1985-01-01

    Catalyst for the production of methane from carbon and/or coal by means of catalytic gasification. The catalyst compostion containing at least two alkali metal salts. A particulate carbonaceous substrate or carrier is used.

  6. Catalyst for Decomposition of Nitrogen Oxides

    NASA Technical Reports Server (NTRS)

    Schryer, David R. (Inventor); Jordan, Jeffrey D. (Inventor); Akyurtlu, Ates (Inventor); Akyurtlu, Jale (Inventor)

    2015-01-01

    This invention relates generally to a platinized tin oxide-based catalyst. It relates particularly to an improved platinized tin oxide-based catalyst able to decompose nitric oxide to nitrogen and oxygen without the necessity of a reducing gas.

  7. Novel Fischer-Tropsch catalysts. [DOE patent

    DOEpatents

    Vollhardt, K.P.C.; Perkins, P.

    Novel compounds are described which are used as improved Fischer-Tropsch catalysts particularly for the conversion of CO + H/sub 2/ to gaseous and liquid hydrocarbons at milder conditions than with prior catalysts.

  8. beta-cyclodextrins-based inclusion complexes of CoFe(2)O(4) magnetic nanoparticles as catalyst for the luminol chemiluminescence system and their applications in hydrogen peroxide detection.

    PubMed

    He, Shaohui; Shi, Wenbing; Zhang, Xiaodan; Li, Jian; Huang, Yuming

    2010-06-30

    beta-cyclodextrins (beta-CD)-based inclusion complexes of CoFe(2)O(4) magnetic nanoparticles (MNPs) were prepared and used as catalysts for chemiluminescence (CL) system using the luminol-hydrogen peroxide CL reaction as a model. The as-prepared inclusion complexes were characterized by XRD (X-ray diffraction), TGA (thermal gravimetric analysis) and FT-IR. The oxidation reaction between luminol and hydrogen peroxide in basic media initiated CL. The effect of beta-CD-based inclusion complexes of CoFe(2)O(4) magnetic nanoparticles and naked CoFe(2)O(4) magnetic nanoparticles on the luminol-hydrogen peroxide CL system was investigated. It was found that inclusion complexes between beta-CD and CoFe(2)O(4) magnetic nanoparticles could greatly enhance the CL of the luminol-hydrogen peroxide system. Investigation on the kinetic curves and the chemiluminescence spectra of the luminol-hydrogen peroxide system demonstrates that addition of CoFe(2)O(4) MNPs or inclusion complexes between beta-CD and CoFe(2)O(4) MNPs does not produce a new luminophor of the chemiluminescent reaction. The luminophor for the CL system was still the excited-state 3-aminophthalate anions (3-APA*). The enhanced CL signals were thus ascribed to the possible catalysis from CoFe(2)O(4) MNPs or inclusion complexes between beta-CD and CoFe(2)O(4) nanoparticles. The feasibility of employing the proposed system for hydrogen peroxide sensing was also investigated. Experimental results showed that the CL emission intensity was linear with hydrogen peroxide concentration in the range of 1.0 x 10(-7) to 4.0 x 10(-6) mol L(-1) with a detection limit of 2.0 x 10(-8) mol L(-1) under optimized conditions. The proposed method has been used to determine hydrogen peroxide in water samples successfully.

  9. Long-Term Testing of Rhodium-Based Catalysts for Mixed Alcohol Synthesis – 2013 Progress Report

    SciTech Connect

    Gerber, Mark A.; Gray, Michel J.; Thompson, Becky L.

    2013-09-23

    The U.S. Department of Energy’s Pacific Northwest National Laboratory has been conducting research since 2005 to develop a catalyst for the conversion of synthesis gas (carbon monoxide and hydrogen) into mixed alcohols for use in liquid transportation fuels. Initially, research involved screening possible catalysts based on a review of the literature, because at that time, there were no commercial catalysts available. The screening effort resulted in a decision to focus on catalysts containing rhodium and manganese. Subsequent research identified iridium as a key promoter for this catalyst system. Since then, research has continued to improve rhodium/manganese/iridium-based catalysts, optimizing the relative and total concentrations of the three metals, examining baseline catalysts on alternative supports, and examining effects of additional promoters. Testing was continued in FY 2013 to evaluate the performance and long-term stability of the best catalysts tested to date. Three tests were conducted. A long-term test of over 2300 hr duration at a single set of operating conditions was conducted with the best carbon-supported catalyst. A second test of about 650 hr duration at a single set of operating conditions was performed for comparison using the same catalyst formulation on an alternative carbon support. A third test of about 680 hr duration at a single set of operating conditions was performed using the best silica-supported catalyst tested to date.

  10. Magnetically retrievable catalysts for organic synthesis.

    PubMed

    Baig, R B Nasir; Varma, Rajender S

    2013-01-28

    The use of magnetic nanoparticles (MNPs) as a catalyst support in organic synthesis is summarized. The recovery of expensive catalysts after catalytic reaction and reusing them without losing their activity is an essential feature in the sustainable process development. The aim of this article is to highlight the progress in the synthesis and catalytic applications of magnetic catalysts in organic synthesis. The heterogenization of the catalyst using magnetic nanoparticles allows it to be recovered and reused using an external magnet.

  11. Experts reveal catalyst-selection methodologies

    SciTech Connect

    1996-10-14

    Refining catalyst selection procedure were discussed in detail at Oil and Gas Journal`s International Catalyst Conference, Feb. 1--2, in Houston. Marathon Oil Co.`s James P. Wick revealed details of Marathon`s program for review and optimization of fluid catalytic cracking (FCC) and hydrotreating catalysts. And renowned FCC expert Del Tolen outlined a step-by-step procedure for choosing an FCC catalyst. The paper describes Marathon`s program and Tolen`s selection process.

  12. TEST REPORT OF MOBILE SOURCE EMISSIONS CONTROL DEVICES DONALDSON COMPANY INC.SERIES 6000 DISEL OXIDATION CATALYST MUFFLER AND SPIRACLE CLOSED CRANKCASE FILTRATION SYSTEM

    EPA Science Inventory

    This report is on testing of a Donaldson Corp. catalytic muffler and closed crankcase filtration system for diesel trucks. It verified the emissions for these systems using low sufur and ultra low sulfur fuel.

  13. Attrition resistant catalysts and sorbents based on heavy metal poisoned FCC catalysts

    DOEpatents

    Gangwal, S.; Jothimurugesan, K.

    1999-07-27

    A heavy metal poisoned, spent FCC catalyst is treated by chemically impregnating the poisoned catalyst with a new catalytic metal or metal salt to provide an attrition resistant catalyst or sorbent for a different catalytic or absorption process, such as catalysts for Fischer-Tropsh Synthesis, and sorbents for removal of sulfur gases from fuel gases and flue-gases. The heavy metal contaminated FCC catalyst is directly used as a support for preparing catalysts having new catalytic properties and sorbents having new sorbent properties, without removing or passivating the heavy metals on the spent FCC catalyst as an intermediate step.

  14. Attrition resistant catalysts and sorbents based on heavy metal poisoned FCC catalysts

    DOEpatents

    Gangwal, Santosh; Jothimurugesan, Kandaswamy

    1999-01-01

    A heavy metal poisoned, spent FCC catalyst is treated by chemically impregnating the poisoned catalyst with a new catalytic metal or metal salt to provide an attrition resistant catalyst or sorbent for a different catalytic or absorption processes, such as catalysts for Fischer-Tropsh Synthesis, and sorbents for removal of sulfur gasses from fuel gases and flue-gases. The heavy metal contaminated FCC catalyst is directly used as a support for preparing catalysts having new catalytic properties and sorbents having new sorbent properties, without removing or "passivating" the heavy metals on the spent FCC catalyst as an intermediate step.

  15. Comparing kinetic profiles between bifunctional and binary type of Zn(salen)-based catalysts for organic carbonate formation

    PubMed Central

    Martín, Carmen

    2014-01-01

    Summary Zn(salen) complexes have been employed as active catalysts for the formation of cyclic carbonates from epoxides and CO2. A series of kinetic experiments was carried out to obtain information about the mechanism for this process catalyzed by these complexes and in particular about the order-dependence in catalyst. A comparative analysis was done between the binary catalyst system Zn(salphen)/NBu4I and a bifunctional system Zn(salpyr)·MeI with a built-in nucleophile. The latter system demonstrates an apparent second-order dependence on the bifunctional catalyst concentration and thus follows a different, bimetallic mechanism as opposed to the binary catalyst that is connected with a first-order dependence on the catalyst concentration and a monometallic mechanism. PMID:25161742

  16. Comparing kinetic profiles between bifunctional and binary type of Zn(salen)-based catalysts for organic carbonate formation.

    PubMed

    Martín, Carmen; Kleij, Arjan W

    2014-01-01

    Zn(salen) complexes have been employed as active catalysts for the formation of cyclic carbonates from epoxides and CO2. A series of kinetic experiments was carried out to obtain information about the mechanism for this process catalyzed by these complexes and in particular about the order-dependence in catalyst. A comparative analysis was done between the binary catalyst system Zn(salphen)/NBu4I and a bifunctional system Zn(salpyr)·MeI with a built-in nucleophile. The latter system demonstrates an apparent second-order dependence on the bifunctional catalyst concentration and thus follows a different, bimetallic mechanism as opposed to the binary catalyst that is connected with a first-order dependence on the catalyst concentration and a monometallic mechanism.

  17. Silver doped catalysts for treatment of exhaust

    DOEpatents

    Park, Paul Worn; Hester, Virgil Raymond; Ragle, Christie Susan; Boyer, Carrie L.

    2009-06-02

    A method of making an exhaust treatment element includes washcoating a substrate with a slurry that includes a catalyst support material. At least some of the catalyst support material from the slurry may be transferred to the substrate, and silver metal (Ag) is dispersed within the catalyst support material.

  18. Catalysts and methods of using the same

    DOEpatents

    Slowing, Igor Ivan; Kandel, Kapil

    2017-02-14

    The present invention provides a catalyst including a mesoporous silica nanoparticle and a catalytic material comprising iron. In various embodiments, the present invention provides methods of using and making the catalyst. In some examples, the catalyst can be used to hydrotreat fatty acids or to selectively remove fatty acids from feedstocks.

  19. 40 CFR 721.9665 - Organotin catalysts.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Organotin catalysts. 721.9665 Section... Substances § 721.9665 Organotin catalysts. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substances identified generically as organotin catalysts (PMNs P-93-853,...

  20. 40 CFR 721.9665 - Organotin catalysts.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Organotin catalysts. 721.9665 Section... Substances § 721.9665 Organotin catalysts. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substances identified generically as organotin catalysts (PMNs P-93-853,...

  1. 40 CFR 721.9665 - Organotin catalysts.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Organotin catalysts. 721.9665 Section... Substances § 721.9665 Organotin catalysts. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substances identified generically as organotin catalysts (PMNs P-93-853,...

  2. 40 CFR 721.9665 - Organotin catalysts.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Organotin catalysts. 721.9665 Section... Substances § 721.9665 Organotin catalysts. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substances identified generically as organotin catalysts (PMNs P-93-853,...

  3. 40 CFR 721.9665 - Organotin catalysts.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Organotin catalysts. 721.9665 Section... Substances § 721.9665 Organotin catalysts. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substances identified generically as organotin catalysts (PMNs P-93-853,...

  4. Highly efficient and robust molecular ruthenium catalysts for water oxidation.

    PubMed

    Duan, Lele; Araujo, Carlos Moyses; Ahlquist, Mårten S G; Sun, Licheng

    2012-09-25

    Water oxidation catalysts are essential components of light-driven water splitting systems, which could convert water to H(2) driven by solar radiation (H(2)O + hν → 1/2O(2) + H(2)). The oxidation of water (H(2)O → 1/2O(2) + 2H(+) + 2e(-)) provides protons and electrons for the production of dihydrogen (2H(+) + 2e(-) → H(2)), a clean-burning and high-capacity energy carrier. One of the obstacles now is the lack of effective and robust water oxidation catalysts. Aiming at developing robust molecular Ru-bda (H(2)bda = 2,2'-bipyridine-6,6'-dicarboxylic acid) water oxidation catalysts, we carried out density functional theory studies, correlated the robustness of catalysts against hydration with the highest occupied molecular orbital levels of a set of ligands, and successfully directed the synthesis of robust Ru-bda water oxidation catalysts. A series of mononuclear ruthenium complexes [Ru(bda)L(2)] (L = pyridazine, pyrimidine, and phthalazine) were subsequently synthesized and shown to effectively catalyze Ce(IV)-driven [Ce(IV) = Ce(NH(4))(2)(NO(3))(6)] water oxidation with high oxygen production rates up to 286 s(-1) and high turnover numbers up to 55,400.

  5. Highly efficient and robust molecular ruthenium catalysts for water oxidation

    PubMed Central

    Duan, Lele; Araujo, Carlos Moyses; Ahlquist, Mårten S.G.; Sun, Licheng

    2012-01-01

    Water oxidation catalysts are essential components of light-driven water splitting systems, which could convert water to H2 driven by solar radiation (H2O + hν → 1/2O2 + H2). The oxidation of water (H2O → 1/2O2 + 2H+ + 2e-) provides protons and electrons for the production of dihydrogen (2H+ + 2e- → H2), a clean-burning and high-capacity energy carrier. One of the obstacles now is the lack of effective and robust water oxidation catalysts. Aiming at developing robust molecular Ru-bda (H2bda = 2,2′-bipyridine-6,6′-dicarboxylic acid) water oxidation catalysts, we carried out density functional theory studies, correlated the robustness of catalysts against hydration with the highest occupied molecular orbital levels of a set of ligands, and successfully directed the synthesis of robust Ru-bda water oxidation catalysts. A series of mononuclear ruthenium complexes [Ru(bda)L2] (L = pyridazine, pyrimidine, and phthalazine) were subsequently synthesized and shown to effectively catalyze CeIV-driven [CeIV = Ce(NH4)2(NO3)6] water oxidation with high oxygen production rates up to 286 s-1 and high turnover numbers up to 55,400. PMID:22753518

  6. Steam reforming of methane over unsupported nickel catalysts

    NASA Astrophysics Data System (ADS)

    Rakass, S.; Oudghiri-Hassani, H.; Rowntree, P.; Abatzoglou, N.

    This paper describes a study of steam reforming of methane using unsupported nickel powder catalysts. The reaction yields were measured and the unsupported nickel powder surface was studied to explore its potential as a catalyst in internal or external reforming solid oxide fuel cells. The unsupported nickel catalyst used and presented in this paper is a pure micrometric nickel powder with an open filamentary structure, irregular 'fractal-like' surface and high external/internal surface ratio. CH 4 conversion increases and coke deposition decreases significantly with the decrease of CH 4:H 2O ratio. At a CH 4:H 2O ratio of 1:2 thermodynamic equilibrium is achieved, even with methane residence times of only ∼0.5 s. The CH 4 conversion is 98 ± 2% at 700 °C and no coke is generated during steam reforming which compares favorably with supported Ni catalyst systems. This ratio was used in further investigations to measure the hydrogen production, the CH 4 conversion, the H 2 yield and the selectivity of the CO, and CO 2 formation. Methane-rich fuel ratios cause significant deviations of the experimental results from the theoretical model, which has been partially correlated to the adsorption of carbon on the surface according to TEM, XPS and elemental analysis. At the fuel: water ratio of 1:2, the unsupported Ni catalyst exhibited high catalytic activity and stability during the steam reforming of methane at low-medium temperature range.

  7. STUDY OF SOLVENT AND CATALYST INTERACTIONS IN DIRECT COAL LIQUEFACTION

    SciTech Connect

    Michael T. Klein

    2000-01-01

    There are several aspects of the Direct Coal Liquefaction process which are not fully understood and which if better understood might lead to improved yields and conversions. Among these questions are the roles of the catalyst and the solvent. While the solvent is known to act by transfer of hydrogen atoms to the free radicals formed by thermal breakdown of the coal in an uncatalyzed system, in the presence of a solid catalyst as is now currently practiced, the yields and conversions are higher than in an uncatalyzed system. The role of the catalyst in this case is not completely understood. DOE has funded many projects to produce ultrafine and more active catalysts in the expectation that better contact between catalyst and coal might result. This approach has met with limited success probably because mass transfer between two solids in a fluid medium i.e. the catalyst and the coal, is very poor. It is to develop an understanding of the role of the catalyst and solvent in Direct Liquefaction that this project was initiated. Specifically it was of interest to know whether direct contact between the coal and the catalyst was important. By separating the solid catalyst in a stainless steel basket permeable to the solvent but not the coal in the liquefaction reactor, it was shown that the catalyst still maintains a catalytic effect on the liquefaction process. There is apparently transfer of hydrogen atoms from the catalyst through the basket wall to the coal via the solvent. Strong hydrogen donor solvents appear to be more effective in this respect than weak hydrogen donors. It therefore appears that intimate contact between catalyst and coal is not a requirement, and that the role of the catalyst may be to restore the hydrogen donor strength to the solvent as the reaction proceeds. A range of solvents of varying hydrogen donor strength was investigated. Because of the extensive use of thermogravimetric analysis in this laboratory in was noted that the peak

  8. Porphyrins as Photoredox Catalysts: Experimental and Theoretical Studies.

    PubMed

    Rybicka-Jasińska, Katarzyna; Shan, Wenqian; Zawada, Katarzyna; Kadish, Karl M; Gryko, Dorota

    2016-11-30

    Metalloporphyrins not only are vital in biological systems but also are valuable catalysts in organic synthesis. On the other hand, catalytic properties of free base porphyrins have been less explored. They are mostly known as efficient photosensitizers for the generation of singlet oxygen via photoinduced energy transfer processes, but under light irradiation, they can also participate in electron transfer processes. Indeed, we have found that free base tetraphenylporphyrin (H2TPP) is an efficient photoredox catalyst for the reaction of aldehydes with diazo compounds leading to α-alkylated derivatives. The performance of a porphyrin catalyst can be optimized by tailoring various substituents at the periphery of the macrocycle at both the β and meso positions. This allows for the fine tuning of their optical and electrochemical properties and hence their catalytic activity.

  9. Liquid-phase oxidation of cyclohexanone over cerium oxide catalyst

    SciTech Connect

    Shen, H.C. ); Weng, H.S. )

    1990-05-01

    Catalytic oxidation of cyclohexanone in the liquid phase with glacial acetic acid as the solvent over cerium oxide was studied between 5 and 15 atm and 98 and 118 {degrees} C in a batch reactor. The products were adipic acid, glutaric acid, succinic acid, caprolactone, carbon oxides, etc. The reaction undergoes a short induction period prior to a rapid reaction regime. In both regimes, the reaction is independent of oxygen pressure when the system pressure is above 10 atm. The induction period is inversely proportional to both of the catalyst weight and cyclohexanone concentration.During the rapid reaction regime, the reaction rate was found to be proportional to the 0.5 power of the catalyst weight and to the 1.5 power of the cyclohexanone concentration. Reaction mechanisms and rate expressions are proposed. The carbon oxides produced in this study were much lower than those previously reported. The cerium oxide catalyst is stable during the reaction.

  10. Nanoengineering Catalyst Supports via Layer-by Layer Surface Functionalization

    SciTech Connect

    Yan, Wenfu; Mahurin, Shannon Mark; Overbury, Steven {Steve} H; Dai, Sheng

    2006-01-01

    Recent progress in the layer-by-layer surface modification of oxides for the preparation of highly active and stable gold nanocatalysts is briefly reviewed. Through a layer-by-layer surface modification approach, the surfaces of various catalyst supports including both porous and nonporous silica materials and TiO{sub 2} nanoparticles were modified with monolayers or multilayers of distinct metal oxide ultra-thin films. The surface-modified materials were used as supports for Au nanoparticles, resulting in highly active nanocatalysts for low-temperature CO oxidation. Good stability against sintering under high-temperature treatment was achieved for a number of the Au catalysts through surface modification of the support material. The surface modification of supports can be a viable route to control both the composition and structure of support and nanoparticle interfaces, thereby tailoring the stability and activity of the supported catalyst systems.

  11. Operando characterization of catalysts through use of a portable microreactor

    DOE PAGES

    Zhao, Shen; Li, Yuanyuan; Stavitski, Eli; ...

    2015-10-09

    To provide new understandings of the mechanisms of catalytic reactions, improved methods are needed than can monitor changes in the electronic, structural and chemical properties of catalysts, doing so in the operando conditions in which catalysts work. We describe here a microreactor-based approach that integrates the capabilities of advanced x-ray, electron, optical and gas-phase compositional analysis techniques in operando conditions. For several exemplary catalytic systems, we demonstrate how this approach enables characterization of three major factors contributing to structure-property correlations evidenced in heterogeneously catalyzed reactions, namely: the atomic structure and elemental compositions of nanocatalysts; the physiochemical properties of the supportmore » and catalyst-support interfaces; and the gas and surface-phase chemistry occurring under operando conditions. We highlight the generality of the approach as well as outline opportunities for future developments.« less

  12. Focussing the view on Nature's water-splitting catalyst

    SciTech Connect

    Messinger, Johannes; Yano, Junko

    2008-01-01

    About 3 billion years ago Nature invented a catalyst that splits water with highefficiency into molecular oxygen and hydrogen equivalents (protons and electrons). This reaction is energetically driven by sun light and the active centre contains relatively cheap and abundant metals: manganese and calcium. This biological system therefore forms the paradigm for all man made attempts for direct solar fuel production and several studies are underway to determine the electronic and geometric structures of this catalyst. In this report we briefly summarize the problems and the current status of these efforts, and propose a DFT-based strategy for obtaining a reliable high resolution structure of this unique catalyst that includes both the inorganic core and the first ligand sphere.

  13. Catalyst. Issue 1, Spring 2008

    ERIC Educational Resources Information Center

    Hawkins, B. Denise, Ed.

    2008-01-01

    Catalyst, a quarterly newsletter from the Institute's Communications Office, contains news, information, and features about the programs and services of the National Institute for Literacy. This issue contains the following articles: (1) Spanish-Language Publication for Parents of Young Readers Among the Institute's New Titles; (2) Director's…

  14. Catalyst: Inquiry for Change, 2001.

    ERIC Educational Resources Information Center

    Hopkins, Ruth A.; Prins, Esther

    This document contains a series of 2001 research briefs, Catalyst: Inquiry for Change (Volume 1), that is part of a research project supported by the Institute for Community College Development at Cornell University, New York. The Institute's research projects are stakeholder driven for the purpose of researching areas of the most interest to…

  15. Perovskite catalysts for oxidative coupling

    DOEpatents

    Campbell, K.D.

    1991-06-25

    Perovskites of the structure A[sub 2]B[sub 2]C[sub 3]O[sub 10] are useful as catalysts for the oxidative coupling of lower alkane to heavier hydrocarbons. A is alkali metal; B is lanthanide or lanthanum, cerium, neodymium, samarium, praseodymium, gadolinium or dysprosium; and C is titanium.

  16. Catalysts for coal liquefaction processes

    DOEpatents

    Garg, D.

    1986-10-14

    Improved catalysts for catalytic solvent refining or hydroliquefaction of non-anthracitic coal at elevated temperatures under hydrogen pressure in a hydrogen donor solvent comprise a combination of zinc or copper, or a compound thereof, and a Group VI or non-ferrous Group VIII metal, or a compound thereof.

  17. Catalysts for coal liquefaction processes

    DOEpatents

    Garg, Diwakar

    1986-01-01

    Improved catalysts for catalytic solvent refining or hydroliquefaction of non-anthracitic coal at elevated temperatures under hydrogen pressure in a hydrogen donor solvent comprise a combination of zinc or copper, or a compound thereof, and a Group VI or non-ferrous Group VIII metal, or a compound thereof.

  18. Perovskite catalysts for oxidative coupling

    DOEpatents

    Campbell, Kenneth D.

    1991-01-01

    Perovskites of the structure A.sub.2 B.sub.2 C.sub.3 O.sub.10 are useful as catalysts for the oxidative coupling of lower alkane to heavier hydrocarbons. A is alkali metal; B is lanthanide or lanthanum, cerium, neodymium, samarium, praseodymium, gadolinium or dysprosium; and C is titanium.

  19. Combinations of Aminocatalysts and Metal Catalysts: A Powerful Cooperative Approach in Selective Organic Synthesis.

    PubMed

    Afewerki, Samson; Córdova, Armando

    2016-11-23

    The cooperation and interplay between organic and metal catalyst systems is of utmost importance in nature and chemical synthesis. Here innovative and selective cooperative catalyst systems can be designed by combining two catalysts that complement rather than inhibit one another. This refined strategy can permit chemical transformations unmanageable by either of the catalysts alone. This review summarizes innovations and developments in selective organic synthesis that have used cooperative dual catalysis by combining simple aminocatalysts with metal catalysts. Considerable efforts have been devoted to this fruitful field. This emerging area employs the different activation modes of amine and metal catalysts as a platform to address challenging reactions. Here, aminocatalysis (e.g., enamine activation catalysis, iminium activation catalysis, single occupied molecular orbital (SOMO) activation catalysis, and photoredox activation catalysis) is employed to activate unreactive carbonyl substrates. The transition metal catalyst complements by activating a variety of substrates through a range of interactions (e.g., electrophilic π-allyl complex formation, Lewis acid activation, allenylidene complex formation, photoredox activation, C-H activation, etc.), and thereby novel concepts within catalysis are created. The inclusion of heterogeneous catalysis strategies allows for "green" chemistry development, catalyst recyclability, and the more eco-friendly synthesis of valuable compounds.

  20. Toward Molecular Catalysts by Computer

    SciTech Connect

    Raugei, Simone; DuBois, Daniel L.; Rousseau, Roger J.; Chen, Shentan; Ho, Ming-Hsun; Bullock, R. Morris; Dupuis, Michel

    2015-02-17

    Rational design of molecular catalysts requires a systematic approach to designing ligands with specific functionality and precisely tailored electronic and steric properties. It then becomes possible to devise computer protocols to predict accurately the required properties and ultimately to design catalysts by computer. In this account we first review how thermodynamic properties such as oxidation-reduction potentials (E0), acidities (pKa), and hydride donor abilities (ΔGH-) form the basis for a systematic design of molecular catalysts for reactions that are critical for a secure energy future (hydrogen evolution and oxidation, oxygen and nitrogen reduction, and carbon dioxide reduction). We highlight how density functional theory allows us to determine and predict these properties within “chemical” accuracy (~ 0.06 eV for redox potentials, ~ 1 pKa unit for pKa values, and ~ 1.5 kcal/mol for hydricities). These quantities determine free energy maps and profiles associated with catalytic cycles, i.e. the relative energies of intermediates, and help us distinguish between desirable and high-energy pathways and mechanisms. Good catalysts have flat profiles that avoid high activation barriers due to low and high energy intermediates. We illustrate how the criterion of a flat energy profile lends itself to the prediction of design points by computer for optimum catalysts. This research was carried out in the Center for Molecular Electro-catalysis, an Energy Frontier Research Center funded by the U.S. Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences. Pacific Northwest National Laboratory (PNNL) is operated for the DOE by Battelle.

  1. Synthesis, characterization and evaluation of CO-oxidation catalysts for high repetition rate CO2 TEA lasers

    NASA Technical Reports Server (NTRS)

    Moser, Thomas P.

    1990-01-01

    An extremely active class of noble metal catalysts supported on titania was developed and fabricated at Hughes for the recombination of oxygen (O2) and carbon monoxide (CO) in closed-cycle CO2 TEA lasers. The incipient wetness technique was used to impregnate titania and alumina pellets with precious metals including platinum and palladium. In particular, the addition of cerium (used as an oxygen storage promoter) produced an extremely active Pt/Ce/TiO2 catalyst. By comparison, the complementary Pt/Ce/ gamma-Al2O3 catalyst was considerably less active. In general, chloride-free catalyst precursors proved critical in obtaining an active catalyst while also providing uniform metal distributions throughout the support structure. Detailed characterization of the Pt/Ce/TiO2 catalyst demonstrated uniform dendritic crystal growth of the metals throughout the support. Electron spectroscopy for Chemical Analysis (ESCA) analysis was used to characterize the oxidation states of Pt, Ce and Ti. The performance of the catalysts was evaluated with an integral flow reactor system incorporating real time analysis of O2 and CO. With this system, the transient and steady-state behavior of the catalysts were evaluated. The kinetic evaluation was complemented by tests in a compact, closed-cycle Hughes CO2 TEA laser operating at a pulse repetition rate of 100 Hz with a catalyst temperature of 75 to 95 C. The Pt/Ce/TiO2 catalyst was compatible with a C(13)O(16)2 gas fill.

  2. Optimization of the electrically heated catalyst for emission purification efficiency

    SciTech Connect

    Jeong, L.; Jang, J.; Yeo, G.; Kim, Y.

    1996-09-01

    It is well known that the EHC (Electrically Heated Catalyst) is very effective for the reduction of cold-start hydrocarbon emissions. To optimize EHC applications for LEV (Low Emission Vehicle) and ULEV (Ultra Low Emission Vehicle) standards, the effects of heating and secondary air injection on the emission purification efficiency in FTP (Federal Test Procedure) were evaluated with three different EHC system configurations. The exhaust manifold location EHC system in which the EHC with a light-off catalyst is installed near the exhaust manifold, yields 0.038g/mile of THC (Total Hydrocarbon emissions) when the test was performed according to the FTP with an engine-aged condition equivalent to 50,000 miles. Therefore, the ULEV standards could be achieved through the system. A new battery system for the EHC and a single battery system for vehicle application were evaluated. Evaluation of the Ni-MH battery for EHC system is included.

  3. Microbial recovery of metals from spent catalysts

    SciTech Connect

    Sperl, P.L.; Sperl, G.T.

    1990-01-01

    This project was initiated on October 1, 1989, for the purpose of recovering metals from spent coal liquefaction catalysts. Two catalyst types are the subject of the contract. The first is a Ni-Mo catalyst supported on alumina (Shell 324) as is used in a pilot scale coal liquefaction facility at Wilsonville, Alabama. The object of the contract is to treat these spent catalysts with microorganisms, especially Thiobacillus ferrooxidans, but also other Thiobacillus sp., to leach and remove the metals (Ni and Mo) from the spent catalysts into a form which can be readily recovered by conventional techniques.

  4. WATER-GAS SHIFT KINETICS OVER IRON OXIDE CATALYSTS AT MEMBRANE REACTOR CONDITIONS

    SciTech Connect

    Carl R.F. Lund

    2002-08-02

    The kinetics of water-gas shift were studied over ferrochrome catalysts under conditions with high carbon dioxide partial pressures, such as would be expected in a membrane reactor. The catalyst activity is inhibited by increasing carbon dioxide partial pressure. A microkinetic model of the reaction kinetics was developed. The model indicated that catalyst performance could be improved by decreasing the strength of surface oxygen bonds. Literature data indicated that adding either ceria or copper to the catalyst as a promoter might impart this desired effect. Ceria-promoted ferrochrome catalysts did not perform any better than unpromoted catalyst at the conditions tested, but copper-promoted ferrochrome catalysts did offer an improvement over the base ferrochrome material. A different class of water-gas shift catalyst, sulfided CoMo/Al{sub 2}O{sub 3} is not affected by carbon dioxide and may be a good alternative to the ferrochrome system, provided other constraints, notably the requisite sulfur level and maximum temperature, are not too limiting. A model was developed for an adiabatic, high-temperature water-gas shift membrane reactor. Simulation results indicate that an excess of steam in the feed (three moles of water per mole of CO) is beneficial even in a membrane reactor as it reduces the rate of adiabatic temperature rise. The simulations also indicate that much greater improvement can be attained by improving the catalyst as opposed to improving the membrane. Further, eliminating the inhibition by carbon dioxide will have a greater impact than will increasing the catalyst activity (assuming inhibition is still operative). Follow-up research into the use of sulfide catalysts with continued kinetic and reactor modeling is suggested.

  5. An antiproton catalyst for inertial confinement fusion propulsion

    NASA Technical Reports Server (NTRS)

    Lewis, Raymond A.; Newton, Richard; Smith, Gerald A.; Toothacker, William S.; Kanzleiter, Randall J.

    1990-01-01

    This paper discusses the concept of an inertial confinement fusion propulsion system involving an antiproton catalyst (for antiproton-induced fission). It is argued that, when the two processes, fusion and antimatter annihilation, are combined into one system, a viable candidate propulsion system for planetary exploration emerges. It is shown that as much as 7.6 GW of power, well within the requrements for interplanetary travel, can be achieved using existing driver technologies and available quantities of antiprotons.

  6. Catalyst deactivation model for residual oil hydrodesulfurization

    SciTech Connect

    Takatsuka, T.; Higasino, S.; Hirohama, S.

    1995-12-31

    Hydrodesulfurization process plays a dominant role in the modern refineries to upgrade residual oil either by removing heterogeneous atoms or by hydrocracking the bottom to distillates products. The practical model is proposed to predict a catalyst life which is the most concern in the process. The catalyst is deactivated in the early stage of the operation by coke deposition on the catalyst active site. The ultimate catalyst life is determined by pore mouth plugging depending on its metal capacity. The phenomena are mathematically described by losses of catalyst surface area and effective diffusivity of feedstock molecules in catalyst pore. The model parameters were collected through the pilot plant tests with different types of catalysts and feedstocks.

  7. Isotope exchange in oxide-containing catalyst

    NASA Technical Reports Server (NTRS)

    Brown, Kenneth G. (Inventor); Upchurch, Billy T. (Inventor); Hess, Robert V. (Inventor); Miller, Irvin M. (Inventor); Schryer, David R. (Inventor); Sidney, Barry D. (Inventor); Wood, George M. (Inventor); Hoyt, Ronald F. (Inventor)

    1989-01-01

    A method of exchanging rare-isotope oxygen for common-isotope oxygen in the top several layers of an oxide-containing catalyst is disclosed. A sample of an oxide-containing catalyst is exposed to a flowing stream of reducing gas in an inert carrier gas at a temperature suitable for the removal of the reactive common-isotope oxygen atoms from the surface layer or layers of the catalyst without damaging the catalyst structure. The reduction temperature must be higher than any at which the catalyst will subsequently operate. Sufficient reducing gas is used to allow removal of all the reactive common-isotope oxygen atoms in the top several layers of the catalyst. The catalyst is then reoxidized with the desired rare-isotope oxygen in sufficient quantity to replace all of the common-isotope oxygen that was removed.

  8. Semisynthetic and Biomolecular Hydrogen Evolution Catalysts.

    PubMed

    Kandemir, Banu; Chakraborty, Saikat; Guo, Yixing; Bren, Kara L

    2016-01-19

    There has been great interest in the development of stable, inexpensive, efficient catalysts capable of reducing aqueous protons to hydrogen (H2), an alternative to fossil fuels. While synthetic H2 evolution catalysts have been in development for decades, recently there has been great progress in engineering biomolecular catalysts and assemblies of synthetic catalysts and biomolecules. In this Forum Article, progress in engineering proteins to catalyze H2 evolution from water is discussed. The artificial enzymes described include assemblies of synthetic catalysts and photosynthetic proteins, proteins with cofactors replaced with synthetic catalysts, and derivatives of electron-transfer proteins. In addition, a new catalyst consisting of a thermophilic cobalt-substituted cytochrome c is reported. As an electrocatalyst, the cobalt cytochrome shows nearly quantitative Faradaic efficiency and excellent longevity with a turnover number of >270000.

  9. The History of Current State of the Art of Propylene Polymerization Catalysts.

    ERIC Educational Resources Information Center

    Goodall, Brian L.

    1986-01-01

    Outlines the development of the modern catalysts for propylene polymerization, considering the historical background; structure of titanium chloride catalysts; first-generation catalysts; cocatalysts; second-generation catalysts; catalysts morphology; and third-generation (supported catalysts). (JN)

  10. Synthesis and characterization of catalysts for the selective transformation of biomass-derived materials

    NASA Astrophysics Data System (ADS)

    Ghampson, Isaac Tyrone

    The experimental work in this thesis focuses on generating catalysts for two intermediate processes related to the thermal conversion of lignocellulosic biomass: the synthesis and characterization of mesoporous silica supported cobalt catalysts for the Fischer-Tropsch reaction, and an exploration of the reactivity of bulk and supported molybdenum-based nitride catalysts for the hydrodeoxygenation (HDO) of guaiacol, a lignin model compound. The first section of the work details the synthesis of a series of silica-supported cobalt Fischer-Tropsch catalysts with pore diameters ranging from 2-23 nm. Detailed X-ray diffraction measurements were used to determine the composition and particle diameters of the metal fraction, analyzed as a three-phase system containing Cofcc, Cohcp and CoO particles. Catalyst properties were determined at three stages in catalyst history: (1) after the initial calcination step to thermally decompose the catalyst precursor into Co3O4, (2) after the hydrogen reduction step to activate the catalyst to Co and (3) after the FT reaction. From the study, it was observed that larger pore diameters supported higher turnover frequency; smaller pore diameters yielded larger mole fraction of CoO; XRD on post-reduction and post-FTS catalyst samples indicated significant changes in dispersivity after reduction. In the next section, the catalytic behaviors of unsupported, activated carbon-, alumina-, and SBA-15 mesoporous silica-supported molybdenum nitride catalysts were evaluated for the hydrodeoxygenation of guaiacol (2-methoxy phenol) at 300°C and 5 MPa. The nitride catalysts were prepared by thermal decomposition of bulk and supported ammonium heptamolybdate to form MoO 3 followed by nitridation in either flowing ammonia or a nitrogen/hydrogen mixture. The catalytic properties were strongly affected by the nitriding and purging treatment as well as the physical and chemical properties of support. The overall reaction was influenced by the

  11. Deactivation by carbon of iron catalysts for indirect liquefaction

    SciTech Connect

    Bartholomew, C.H.

    1990-10-11

    This report describes recent progress in a fundamental, three-year investigation of carbon formation and its effects on the activity and selectivity of promoted iron catalysts for Fischer-Tropsch (FT) synthesis, the objectives of which are: determine rates and mechanisms of carbon deactivation of unsupported Fe and Fe/K catalysts during CO hydrogenation over a range of CO concentrations, CO:H{sub 2} ratios, and temperatures; model the rates of deactivation of the same catalysts in fixed-bed reactors. During the thirteenth quarter design of software for a computer-automated reactor system to be used in the kinetic and deactivation studies was continued. Further progress was made toward the completion of the control language, control routines, and software for operating this system. Progress was also made on the testing of the system hardware and software. H{sub 2} chemisorption capacities and activity selectivity data were also measured for three iron catalysts promoted with 1% alumina. 47 refs., 8 figs., 1 tab.

  12. TEST REPORT OF MOBILE SOURCE EMISSIONS CONTROL DEVICES DONALDSON COMPANY INC.SERIES 6100 DIESEL OXIDATION CATALYST MUFFLER AND SPIRACLE CLOSED CRANKCASE FILTRATION SYSTEM

    EPA Science Inventory

    This report is on an environmental verification of the emissions characteristics of a Donaldson Corp. catalytic muffler and catalyic crankcase emissions control. It was found the systems reduced emissions.

  13. Palladium nanoparticles in ionic liquids: reusable catalysts for aerobic oxidation of alcohols

    NASA Astrophysics Data System (ADS)

    Mondal, Arijit; Das, Amit; Adhikary, Bibhutosh; Mukherjee, Deb Kumar

    2014-04-01

    The search for more efficient catalytic systems that might combine the advantages of both homogenous (catalyst modulation) and heterogenous catalysis (catalyst recycling) is still the challenge of modern chemistry. With the advent of nanochemistry, it has been possible to prepare soluble analogues of heterogenous catalysts. These nanoparticles are generally stabilized against aggregation into larger less active particles by electrostatic or steric protection. In the present case, we demonstrate the use of room temperature ionic liquids (ILs) as effective agents of dispersion of palladium nanoparticles (prepared from palladium chloride with 5 ± 0.5 nm size distribution) that are recyclable catalysts for aerobic oxidation of alcohols under mild conditions. The particles suspended in ILs show no metal agglomeration or loss of catalytic activity even on prolonged use. An attempt has been made to elucidate the reaction mechanism of aerobic alcohol oxidation using a soluble palladium catalyst.

  14. Synthesis of methyl esters from waste cooking oil using construction waste material as solid base catalyst.

    PubMed

    Balakrishnan, K; Olutoye, M A; Hameed, B H

    2013-01-01

    The current research investigates synthesis of methyl esters by transesterification of waste cooking oil in a heterogeneous system, using barium meliorated construction site waste marble as solid base catalyst. The pretreated catalyst was calcined at 830 °C for 4h prior to its activity test to obtained solid oxide characterized by scanning electron microscopy/energy dispersive spectroscopy, BET surface area and pore size measurement. It was found that the as prepared catalyst has large pores which contributed to its high activity in transesterification reaction. The methyl ester yield of 88% was obtained when the methanol/oil molar ratio was 9:1, reaction temperature at 65 °C, reaction time 3h and catalyst/oil mass ratio of 3.0 wt.%. The catalyst can be reused over three cycles, offer low operating conditions, reduce energy consumption and waste generation in the production of biodiesel.

  15. Efficient catalyst removal and recycling in copolymerization of epoxides with carbon dioxide via simple liquid-liquid phase separation.

    PubMed

    Nakano, Koji; Fujie, Ryuhei; Shintani, Ryo; Nozaki, Kyoko

    2013-10-18

    A simple and efficient catalyst removal system has been developed in the cobalt-salen-catalyzed copolymerization of propylene oxide with carbon dioxide. The present system requires no prior modification of the catalyst, and the removal is achieved by simple addition of myristic acid, followed by organic liquid-liquid phase separation.

  16. A series of copper-free ternary oxide catalysts ZnAlCex used for hydrogen production via dimethyl ether steam reforming

    NASA Astrophysics Data System (ADS)

    Zhang, Lijie; Meng, Ming; Wang, Xiaojing; Zhou, Shuang; Yang, Lijuan; Zhang, Tianyong; Zheng, Lirong; Zhang, Jing; Hu, Tiandou

    2014-12-01

    Ce-substituted ternary oxide catalysts ZnAlCex were prepared and employed in dimethyl ether steam reforming (DME SR) to produce hydrogen. XRD, XAFS (XANES & EXAFS), H2O-TPD, CH3OH-TPD and TPSR techniques were used for catalyst characterization. It is found that the catalytic performance of these catalysts is dependent on Ce content. The catalyst containing 20 wt% CeO2 exhibits the best catalytic performance. Its calculated TOF (0.034 s-1) is nearly three times to that of ZnAlO. The kinetic results reveal that the addition of 20 wt% CeO2 to ZnAlCex greatly decreases the apparent activation energy (Ea) of DME SR, due to the formation of new reaction sites such as Ce4+-O-Zn2+ linkages. XRD and EXAFS analyses indicate that Ce addition can not only decrease the crystallite size of ZnO and ZnAl2O4, but also tune the relative contents of them. The results of H2O-TPD and CH3OH-TPD show that Ce addition can lower H2 desorption temperature, which accounts well for the better catalytic performance of ZnAlCex. It is worth noting that the Zn-based catalysts display much lower CO selectivity than the Cu-based one, especially the Ce-substituted ZnAlCex. Start-off durability tests demonstrate that this series of catalysts also possess high catalytic stability.

  17. Novel bimetallic dispersed catalysts for temperature-programmed coal liquefaction. Final report

    SciTech Connect

    Chunshan Song; Schobert, H.H.; Parfitt, D.P.

    1997-11-01

    Development of new catalysts is a promising approach to more efficient coal liquefaction. It has been recognized that dispersed catalysts are superior to supported catalysts for primary liquefaction of coals, because the control of initial coal dissolution or depolymerization requires intimate contact between the catalyst and coal. This research is a fundamental and exploratory study on catalytic coal liquefaction, with the emphasis on exploring novel bimetallic dispersed catalysts for coal liquefaction and the effectiveness of temperature-programmed liquefaction using dispersed catalysts. The primary objective of this research was to explore novel bimetallic dispersed catalysts from organometallic molecular precursors, that could be used in low concentrations but exhibit relatively high activity for efficient hydroliquefaction of coals under temperature-programmed conditions. We have synthesized and tested various catalyst precursors in liquefaction of subbituminous and bituminous coals and in model compound studies to examine how do the composition and structure of the catalytic precursors affect their effectiveness for coal liquefaction under different reaction conditions, and how do these factors affect their catalytic functions for hydrogenation of polyaromatic hydrocarbons, for cleavage of C-C bonds in polycyclic systems such as 4-(1-naphthylmethyl)bibenzyl, for hydrogenolysis of C-O bond such as that in dinaphthylether, for hydrodeoxygenation of phenolic compounds and other oxygen-containing compounds such as xanthene, and for hydrodesulfurization of polycyclic sulfur compounds such as dibenzothiophene. The novel bimetallic and monometallic precursors synthesized and tested in this project include various Mo- and Fe-based compounds.

  18. Development of new transition metal oxide catalysts for the destruction of PCDD/Fs.

    PubMed

    Yu, Ming-Feng; Li, Wen-Wei; Li, Xiao-Dong; Lin, Xiao-Qing; Chen, Tong; Yan, Jian-Hua

    2016-08-01

    Various transition metal oxide and vanadium-containing multi-metallic oxide catalysts were developed for the destruction of PCDD/Fs (polychlorinated dibenzo-p-dioxins and furans). A stable PCDD/Fs generating system was installed to support the catalytic destruction tests in this study. Nano-titania supported vanadium catalyst (VOx/TiO2) showed the highest activity, followed by CeOx, MnOx, WOx and finally MoOx. Multi-metallic oxide catalysts, prepared by doping WOx, MoOx, MnOx and CeOx into VOx/TiO2 catalysts, showed different activities on the decomposition of PCDD/Fs. The highest destruction efficiency of 92.5% was observed from the destruction test over VOxCeOx/TiO2 catalyst. However, the addition of WOx and MoOx even played a negative role in multi-metallic VOx/TiO2 catalysts. Characterizations of transition metal oxides and multi-metallic VOx/TiO2 catalysts were also investigated with XRD and TPR. After the catalysts were used, the conversion from high valent metals to low valence states was observed by XPS.

  19. Activity of platinum/carbon and palladium/carbon catalysts promoted by Ni2 P in direct ethanol fuel cells.

    PubMed

    Li, Guoqiang; Feng, Ligang; Chang, Jinfa; Wickman, Björn; Grönbeck, Henrik; Liu, Changpeng; Xing, Wei

    2014-12-01

    Ethanol is an alternative fuel for direct alcohol fuel cells, in which the electrode materials are commonly based on Pt or Pd. Owing to the excellent promotion effect of Ni2 P that was found in methanol oxidation, we extended the catalyst system of Pt or Pd modified by Ni2 P in direct ethanol fuel cells. The Ni2 P-promoted catalysts were compared to commercial catalysts as well as to reference catalysts promoted with only Ni or only P. Among the studied catalysts, Pt/C and Pd/C modified by Ni2 P (30 wt %) showed both the highest activity and stability. Upon integration into the anode of a homemade direct ethanol fuel cell, the Pt-Ni2 P/C-30 % catalyst showed a maximum power density of 21 mW cm(-2) , which is approximately two times higher than that of a commercial Pt/C catalyst. The Pd-Ni2 P/C-30 % catalyst exhibited a maximum power density of 90 mW cm(-2) . This is approximately 1.5 times higher than that of a commercial Pd/C catalyst. The discharge stability on both two catalysts was also greatly improved over a 12 h discharge operation.

  20. Catalyst for selective conversion of synthesis gas and method of making the catalyst

    DOEpatents

    Dyer, Paul N.; Pierantozzi, Ronald

    1986-01-01

    A Fischer-Tropsch (F-T) catalyst, a method of making the catalyst and an F-T process utilizing the catalyst by which synthesis gas, particularly carbon-monoxide rich synthesis gas is selectively converted to higher hydrocarbons of relatively narrow carbon number range. In general, the selective and notably stable catalyst, consists of an inert carrier first treated with a Group IV B metal compound (such as zirconium or titanium), preferably an alkoxide compound, and subsequently treated with an organic compound of an F-T metal catalyst, such as cobalt, iron or ruthenium carbonyl. Reactions with air and water and calcination are specifically avoided in the catalyst preparation procedure.