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Sample records for supported copper catalysts

  1. Zircon Supported Copper Catalysts for the Steam Reforming of Methanol

    Science.gov (United States)

    Widiastri, M.; Fendy, Marsih, I. N.

    2008-03-01

    Steam reforming of methanol (SRM) is known as one of the most favorable catalytic processes for producing hydrogen. Current research on zirconia, ZrO2 supported copper catalyst revealed that CuO/ZrO2 as an active catalyst for the SRM. Zircon, ZrSiO4 is available from the by-product of tin mining. In the work presented here, the catalytic properties of CuO/ZrSiO4 with various copper oxide compositions ranging from 2.70% (catalyst I), 4.12% (catalyst II), and 7.12%-mass (catalyst III), synthesized by an incipient wetness impregnation technique, were investigated to methanol conversion, selectivity towards CO formation, and effect of ZnO addition (7.83%CuO/8.01%ZnO/ZrSiO4 = catalyst V). The catalytic activity was obtained using a fixed bed reactor and the zircon supported catalyst activity was compared to those of CuO/ZnO/Al2O3 catalyst (catalyst IV) and commercial Kujang LTSC catalyst. An X-ray powder diffraction (XRD) analysis was done to identify the abundant phases of the catalysts. The catalysts topography and particle diameter were measured with scanning electron microscopy (SEM) and composition of the catalysts was measured by SEM-EDX, scanning electron microscope-energy dispersive using X-ray analysis. The results of this research provide information on the possibility of using zircon (ZrSiO4) as solid support for SRM catalysts.

  2. A copper catalyst on nonporous supports based on copper oxalate as a precursor

    Science.gov (United States)

    Zhitnev, Yu. N.; Tveritinova, E. A.; Spiridonov, F. M.; Lunin, V. V.

    2010-07-01

    A method for obtaining copper catalysts on nonporous supports by the thermal decomposition of copper oxalate in the absence of oxygen was suggested. The catalytic properties of the catalyst were studied in the model reaction of the conversion of propanol-2 into acetone and propylene. The influence of the content of copper in the catalyst, reaction temperature, and conditions of oxalate decomposition on the degree of alcohol conversion and ratio between reaction channels was studied. Electron photomicrographs were obtained, specific surface areas were measured, and X-ray powder patterns of the catalyst were recorded.

  3. Support Functionalization To Retard Ostwald Ripening in Copper Methanol Synthesis Catalysts

    NARCIS (Netherlands)

    van den Berg, Roy|info:eu-repo/dai/nl/358212049; Parmentier, Tanja E.; Elkjaer, Christian F.; Gommes, Cedric J.; Sehested, Jens; Helveg, Stig; de Jongh, Petra E.|info:eu-repo/dai/nl/186125372; de Jong, Krijn P.|info:eu-repo/dai/nl/06885580X

    A main reason for catalyst deactivation in supported catalysts for methanol synthesis is copper particle growth. We have functionalized the support surface in order to suppress the formation and/or transport of mobile copper species and thereby catalyst deactivation. A Stober silica support was

  4. Copper nitrate redispersion to arrive at highly active silica-supported copper catalysts

    NARCIS (Netherlands)

    Munnik, P.|info:eu-repo/dai/nl/328228524; Wolters, M.|info:eu-repo/dai/nl/304829560; Gabrielsson, A.; Pollington, S.D.; Headdock, G.; Bitter, J.H.|info:eu-repo/dai/nl/160581435; de Jongh, P.E.|info:eu-repo/dai/nl/186125372; de Jong, K.P.|info:eu-repo/dai/nl/06885580X

    2011-01-01

    In order to obtain copper catalysts with high dispersions at high copper loadings, the gas flow rate and gas composition was varied during calcination of silica gel impregnated with copper nitrate to a loading of 18 wt % of copper. Analysis by X-ray diffraction (XRD), N2O chemisorption, and

  5. Synthesis of carbon-supported copper catalyst and its catalytic performance in methanol dehydrogenation

    Science.gov (United States)

    Shelepova, Ekaterina V.; Vedyagin, Aleksey A.; Ilina, Ludmila Yu.; Nizovskii, Alexander I.; Tsyrulnikov, Pavel G.

    2017-07-01

    Carbon-supported copper catalyst was prepared by incipient wetness impregnation of Sibunit with an aqueous solution of copper nitrate. Copper loading was 5 wt.%. Temperature of reductive pretreatment was varied within a range of 200-400 °C. The samples were characterized by transmission electron microscopy, X-ray diffraction analysis, X-ray photoelectron and X-ray absorption spectroscopies. Catalytic activity of the samples was studied in a reaction of methanol dehydrogenation. Silica-based catalyst with similar copper loading was used as a reference. It was found that copper is distributed over the surface of support in the form of metallic and partially oxidized particles of about 12-17 nm in size. Diminished interaction of copper with support was supposed to be responsible for high catalytic activity.

  6. Synthesis of carbon-supported copper catalyst and its catalytic performance in methanol dehydrogenation

    Energy Technology Data Exchange (ETDEWEB)

    Shelepova, Ekaterina V. [Boreskov Institute of Catalysis SB RAS, pr. Ac. Lavrentieva, 5, Novosibirsk, 630090 (Russian Federation); National Research Tomsk Polytechnic University, Lenin av., 30, Tomsk, 634050 (Russian Federation); Vedyagin, Aleksey A., E-mail: vedyagin@catalysis.ru [Boreskov Institute of Catalysis SB RAS, pr. Ac. Lavrentieva, 5, Novosibirsk, 630090 (Russian Federation); National Research Tomsk Polytechnic University, Lenin av., 30, Tomsk, 634050 (Russian Federation); Ilina, Ludmila Yu.; Nizovskii, Alexander I. [Boreskov Institute of Catalysis SB RAS, pr. Ac. Lavrentieva, 5, Novosibirsk, 630090 (Russian Federation); Tsyrulnikov, Pavel G. [Institute of Hydrocarbon Processing SB RAS, Neftezavodskaya st., 54, Omsk, 644040 (Russian Federation)

    2017-07-01

    Highlights: • Carbon-supported copper catalyst was studied in dehydrogenation of methanol. • Reduction temperature affected size of Cu particles and Cu{sup 0}/Cu{sup 2+} ratio. • Reduction at 400 °C was required to obtain high methyl formate yield. - Abstract: Carbon-supported copper catalyst was prepared by incipient wetness impregnation of Sibunit with an aqueous solution of copper nitrate. Copper loading was 5 wt.%. Temperature of reductive pretreatment was varied within a range of 200–400 °C. The samples were characterized by transmission electron microscopy, X-ray diffraction analysis, X-ray photoelectron and X-ray absorption spectroscopies. Catalytic activity of the samples was studied in a reaction of methanol dehydrogenation. Silica-based catalyst with similar copper loading was used as a reference. It was found that copper is distributed over the surface of support in the form of metallic and partially oxidized particles of about 12–17 nm in size. Diminished interaction of copper with support was supposed to be responsible for high catalytic activity.

  7. Copper-containing zeolite catalysts

    Science.gov (United States)

    Price, Geoffrey L.; Kanazirev, Vladislav

    1996-01-01

    A catalyst useful in the conversion of nitrogen oxides or in the synthesis of nitriles or imines from amines, formed by preparing an intimate mechanical mixture of a copper (II)-containing species, such as CuO or CuCl.sub.2, or elemental copper, with a zeolite having a pore mouth comprising 10 oxygen atoms, such as ZSM-5, converting the elemental copper or copper (II) to copper (I), and driving the copper (I) into the zeolite.

  8. Carbon-Supported Copper Nanomaterials: Recyclable Catalysts for Huisgen [3+2] Cycloaddition Reactions.

    Science.gov (United States)

    Shaygan Nia, Ali; Rana, Sravendra; Döhler, Diana; Jirsa, Franz; Meister, Annette; Guadagno, Liberata; Koslowski, Eik; Bron, Michael; Binder, Wolfgang H

    2015-07-20

    Highly disperse copper nanoparticles immobilized on carbon nanomaterials (CNMs; graphene/carbon nanotubes) were prepared and used as a recyclable and reusable catalyst to achieve Cu(I) -catalyzed [3+2] cycloaddition click chemistry. Carbon nanomaterials with immobilized N-heterocyclic carbene (NHC)-Cu complexes prepared from an imidazolium-based carbene and Cu(I) show excellent stability including high efficiency at low catalyst loading. The catalytic performance evaluated in solution and in bulk shows that both types of Cu-CNMs can function as an effective recyclable catalysts (more than 10 cycles) for click reactions without decomposition and the use of external additives. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Performance of supported catalysts based on a new copper vanadate-type precursor for catalytic oxidation of toluene

    Energy Technology Data Exchange (ETDEWEB)

    Palacio, L.A. [Grupo Catalizadores y Adsorbentes, Universidad de Antioquia, A.A. 1226 - Medellin (Colombia); Silva, E.R.; Catalao, R. [IBB-Institute for Biotechnology and Bioengineering, Instituto Superior Tecnico, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Silva, J.M. [IBB-Institute for Biotechnology and Bioengineering, Instituto Superior Tecnico, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Instituto Superior Engenharia de Lisboa, Departamento de Engenharia Quimica. Av. Cons. Emidio Navarro, 1959-007 Lisboa (Portugal); Hoyos, D.A. [Grupo Catalizadores y Adsorbentes, Universidad de Antioquia, A.A. 1226 - Medellin (Colombia); Ribeiro, F.R. [IBB-Institute for Biotechnology and Bioengineering, Instituto Superior Tecnico, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Ribeiro, M.F. [IBB-Institute for Biotechnology and Bioengineering, Instituto Superior Tecnico, Av. Rovisco Pais, 1049-001 Lisboa (Portugal)], E-mail: filipa.ribeiro@ist.utl.pt

    2008-05-01

    A new copper vanadate precursor with the formula NH{sub 4}[Cu{sub 2.5}V{sub 2}O{sub 7}(OH){sub 2}].H{sub 2}O was synthesized and deposited on two different supports, ZSM-5 and amorphous SiO{sub 2}, by a hydrothermal method or by mechanical mixture. The catalytic behaviour was evaluated in the total oxidation of toluene and the characterization was performed by H{sub 2}-temperature-programmed reduction (H{sub 2}-TPR), thermogravimetric analysis, elemental analysis, UV-vis diffuse reflectance spectroscopy and X-ray diffraction. It was found that the copper vanadate phase comprises two mixed oxides, one of them crystalline, the Ziesite phase, and the other one amorphous. The supported catalysts presented a content of copper vanadate phase of about 9-11 wt.%. The copper vanadate deposited on ZSM-5 by the hydrothermal method evidences the best performance in the oxidation of toluene. This behaviour can be associated with the smaller size and higher dispersion of the particles on the support, which was confirmed by their better reducibility and higher band gap energy value compared with the other series of studied catalysts.

  10. Conversion of succinic acid to 1,4-butanediol via dimethyl succinate over rhenium nano-catalyst supported on copper-containing mesoporous carbon.

    Science.gov (United States)

    Hong, Ung Gi; Kim, Jeong Kwon; Lee, Joongwon; Lee, Jong Kwon; Yi, Jongheop; Song, In Kyu

    2014-11-01

    Copper-containing mesoporous carbons (XCu-MC) with different copper content (X = 8.0, 12.7, 15.9, 23.3, and 26.8 wt%) were prepared by a single-step surfactant-templating method. Rhenium nano-catalysts supported on copper-containing mesoporous carbons (Re/XCu-MC) were then prepared by an incipient wetness method. Re/XCu-MC (X = 8.0, 12.7, 15.9, 23.3, and 26.8 wt%) catalysts were characterized by nitrogen adsorption-desorption isotherm, HR-TEM, FT-IR, and H2- TPR analyses. Liquid-phase hydrogenation of succinic acid to 1,4-butanediol (BDO) via dimethyl succinate (DMS) was carried out over Re/XCu-MC catalysts in a batch reactor. The effect of copper content on the physicochemical properties and catalytic activities of Re/XCu-MC catalysts in the hydrogenation of succinic acid to BDO was investigated. Re/XCu-MC catalysts retained different physicochemical properties depending on copper content. In the hydrogenation of succinic acid to BDO, yield for BDO showed a volcano-shaped trend with respect to copper content. Thus, an optimal copper content was required to achieve maximum catalytic performance of Re/XCu-MC. It was also observed that yield for BDO increased with increasing the amount of hydrogen consumption by copper in the Re/XCu-MC catalysts.

  11. Hexaniobate as nanoscale catalyst support for copper oxidase mimics based on metal complexes

    Energy Technology Data Exchange (ETDEWEB)

    Bizeto, Marcos Augusto [Universidade Federal de Sao Paulo (UNIFESP), Diadema, SP (Brazil); Alves, Wendel Andrade [Universidade Federal do ABC, SP (Brazil); Barbosa, Cesar Augusto Sales [Universidade Estadual de Campinas (UNICAMP), Campinas, SP (Brazil). Bunge Fertilizantes; Ferreira, Ana Maria da Costa; Constantino, Vera Regina Leopoldo [Universidade de Sao Paulo (USP), SP (Brazil). Inst. de Quimica

    2006-07-01

    Inorganic materials such as nanoporous zeolitic systems and layered structures have been considered special containers for chemical reactions, in which catalytically active species can show an energetic and/or spatial configuration that favors reactions of low activation energy. In this work, hexaniobate nanoscrolls were evaluated as a support for a metal complex that mimics copper oxidase enzymes. The cationic metal complex, 2-[2-(2-pyridyl)ethylimino-1-ethyl]pyridine-imidazole copper(II), [Cu(apip)imH]{sup 2}, was immobilized into hexaniobate scrolls by an ion exchange reaction. Chemical analysis, electronic and vibrational spectroscopies, thermogravimetric analysis and electron paramagnetic resonance (EPR) techniques were used to characterize the hexaniobatecopper complex system. High-resolution transmission electron microscopy of isolated hexaniobate particles containing the cationic complex showed the presence of scrolls with a wall thickness of about 4.5-7.0 nm and an external diameter of about 25-30 nm. X ray diffraction patterns confirmed the presence of the copper complex in the interlayer spaces of hexaniobate nanoscrolls. The reactivity of the copper complex supported on hexaniobate nanoscrolls was investigated for catechol oxidation in the presence of hydrogen peroxide. The formation of hydroxyl radicals (-OH) during the reaction was suggested by EPR data, which were obtained by monitoring the kinetics of DMPO/-OH adduct formation (DMPO is 5,5' dimethyl-1-pyrroline-N-oxide, used as spin trap). (author)

  12. Copper supported on nanostructured mesoporous ceria-titania composites as catalysts for sustainable environmental protection: Effect of support composition

    Czech Academy of Sciences Publication Activity Database

    Issa, G. S.; Tsoncheva, T.; Mileva, A.; Dimitrov, M.D.; Kovacheva, D.; Henych, Jiří; Štengl, Václav

    2017-01-01

    Roč. 49, SI D (2017), s. 55-62 ISSN 0324-1130 Institutional support: RVO:61388980 Keywords : Mesoporous nanostructured ceria-titania doped with copper * template-assisted hydrothermal synthesis * ethyl acetate oxidation * methanol decomposition Subject RIV: CA - Inorganic Chemistry OBOR OECD: Inorganic and nuclear chemistry Impact factor: 0.238, year: 2016

  13. Automated synthesis of a 96 product-sized library of triazole derivatives using a solid phase supported copper catalyst.

    Science.gov (United States)

    Jlalia, Ibtissem; Beauvineau, Claire; Beauvière, Sophie; Onen, Esra; Aufort, Marie; Beauvineau, Aymeric; Khaba, Eihab; Herscovici, Jean; Meganem, Faouzi; Girard, Christian

    2010-04-28

    This article deal with the parallel synthesis of a 96 product-sized library using a polymer-based copper catalyst that we developed which can be easily separated from the products by simple filtration. This gave us the opportunity to use this catalyst in an automated chemical synthesis station (Chemspeed ASW-2000). Studies and results about the preparation of the catalyst, its use in different solvent systems, its recycling capabilities and its scope and limitations in the synthesis of this library will be addressed. The synthesis of the triazole library and the very good results obtained will finally be discussed.

  14. Electroreduction of CO2 into Ethanol over an Active Catalyst: Copper Supported on Titania

    Directory of Open Access Journals (Sweden)

    Jing Yuan

    2017-07-01

    Full Text Available A simple, inexpensive, and novel method was used to prepare electrocatalysts from Cu supported on titanium dioxide (Cu/TiO2. XRD, SEM, and TEM characterizations confirmed different loadings of Cu nanoparticles (NPs on TiO2. Cyclic voltammetry tests indicated that Cu/TiO2 exhibited lower overpotential for CO2 reduction than that of Cu NPs. Moreover, 40 wt % Cu/TiO2 exhibited the highest faradaic efficiency for ethanol (FEethanol of 27.4%, which is approximately 10-fold higher than that for Cu NPs (FEethanol = 2.7%. The 40 wt % Cu/TiO2 electrocatalyst exhibits a stable current density of 8.66 mA/cm2 over a 25 h stability test. The high efficiency towards CO2 electroreduction to ethanol may be attributed to the synergistic effect of Cu and TiO2 NPs. This work highlights the importance of compositional effect of NPs on their catalytic activities and provides a strategy for designing efficient catalysts for CO2 electroreduction in the future.

  15. Ethyl Acetate Abatement on Copper Catalysts Supported on Ceria Doped with Rare Earth Oxides.

    Science.gov (United States)

    Carabineiro, Sónia Alexandra Correia; Konsolakis, Michalis; Marnellos, George Emmanouil-Nontas; Asad, Muhammad Faizan; Soares, Olívia Salomé Gonçalves Pinto; Tavares, Pedro Bandeira; Pereira, Manuel Fernando Ribeiro; Órfão, José Joaquim de Melo; Figueiredo, José Luís

    2016-05-17

    Different lanthanide (Ln)-doped cerium oxides (Ce0.5Ln0.5O1.75, where Ln: Gd, La, Pr, Nd, Sm) were loaded with Cu (20 wt. %) and used as catalysts for the oxidation of ethyl acetate (EtOAc), a common volatile organic compound (VOC). For comparison, both Cu-free (Ce-Ln) and supported Cu (Cu/Ce-Ln) samples were characterized by N₂ adsorption at -196 °C, scanning/transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy and temperature programmed reduction in H₂. The following activity sequence, in terms of EtOAc conversion, was found for bare supports: CeO₂ ≈ Ce0.5Pr0.5O1.75 > Ce0.5Sm0.5O1.75 > Ce0.5Gd0.5O1.75 > Ce0.5Nd0.5O1.75 > Ce0.5La0.5O1.75. Cu addition improved the catalytic performance, without affecting the activity order. The best catalytic performance was obtained for Cu/CeO₂ and Cu/Ce0.5Pr0.5O1.75 samples, both achieving complete EtOAc conversion below ca. 290 °C. A strong correlation was revealed between the catalytic performance and the redox properties of the samples, in terms of reducibility and lattice oxygen availability. Νo particular correlation between the VOC oxidation performance and textural characteristics was found. The obtained results can be explained in terms of a Mars-van Krevelen type redox mechanism involving the participation of weakly bound (easily reduced) lattice oxygen and its consequent replenishment by gas phase oxygen.

  16. Thermal and plasmochemical activation of the zirconia-supported copper catalyst for ethanol dehydrogenation

    Science.gov (United States)

    Chuklina, S. G.; Pylinina, A. I.; Khoroshilov, V. V.

    2017-05-01

    It was shown that copper-containing nanocomposites based on t-zirconium dioxide 5% Cu/t-ZrO2 can be activated using preliminary treatments in high-frequency (HF) hydrogen plasma and critical low-temperature treatments. The increased activity was explained by the formation of many active centers due to the creation of additional t-zirconia defects as a result of the redistribution of copper ions on its surface before the reductive treatment.

  17. Dynamics of carbide formation in iron-supported catalysts of the Fischer-Tropsch process promoted by copper and potassium

    Science.gov (United States)

    Kazak, V. O.; Pankina, G. V.; Chernavskii, P. A.; Lunin, V. V.

    2017-05-01

    The kinetics of the formation of iron carbides during the activation of iron-coated catalyst for Fischer-Tropsch synthesis promoted by copper and potassium, and by carbon monoxide and syngas, is studied. It is established that the presence of copper lowers the initial temperature of hematite reduction to magnetite and leads to the formation of carbide in both CO and CO/H2. Potassium slows the rate of magnetite formation, but it accelerates the formation of iron oxide. It is shown that the rate of carbide formation during magnetite reduction for catalysts is half that in the reaction of hematite reduction to magnetite in both CO and CO/H2.

  18. A Facile Synthesis of Hollow Palladium/Copper Alloy Nanocubes Supported on N-Doped Graphene for Ethanol Electrooxidation Catalyst

    Directory of Open Access Journals (Sweden)

    Zhengyu Bai

    2015-04-01

    Full Text Available In this paper, a catalyst of hollow PdCu alloy nanocubes supported on nitrogen-doped graphene support (H-PdCu/ppy-NG is successfully synthesized using a simple one-pot template-free method. Two other catalyst materials such as solid PdCu alloy particles supported on this same nitrogen-doped graphene support (PdCu/ppy-NG and hollow PdCu alloy nanocubes supported on the reduced graphene oxide support (H-PdCu/RGO are also prepared using the similar synthesis conditions for comparison. It is found that, among these three catalyst materials, H-PdCu/ppy-NG gives the highest electrochemical active area and both the most uniformity and dispersibility of H-PdCu particles. Electrochemical tests show that the H-PdCu/ppy-NG catalyst can give the best electrocatalytic activity and stability towards the ethanol electrooxidation when compared to other two catalysts. Therefore, H-PdCu/ppy-NG should be a promising catalyst candidate for anodic ethanol oxidation in direct ethanol fuel cells.

  19. Synthesis of copper chromite catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Kawamoto, A.M.; Claudio Rezende, L. [Space Aeronautical Institute/Aerospace Center, Chemistry Div., Sao Jose dos Campos, SP (Brazil); Claudio Pardini, L. [Space Aeronautical Institute/Aerospace Center, Materials Div., Sao Jose dos Campos, SP (Brazil)

    2004-10-01

    The present work has the objective to investigate the catalytic behaviour of copper chromite (CuCr{sub 2}O{sub 4}) in the burning rate of poly-butadiene hydroxyl terminated (HTPB) which is an ammonium perchlorate propellant for solid fueled rockets. Copper chromite catalysts were prepared by ceramic and coprecipitation methods and characterized by X-ray diffraction, scanning electron microscopy (SEM), elemental, differential calorimetric (DSC), thermogravimetric and granulometric analysis, mass spectroscopy and infrared spectroscopy (IR). Elemental and IR analysis have shown similarities among the samples for both synthetic methods. However, DSC, SEM and X-ray analysis of the samples synthesized by coprecipitation method presented different physical properties. For those samples, DSC could identify a tetragonal {yields} cubic phase transition, SEM showed particles with defined crystalline shapes and X-ray analysis contains the main assignments which identify the formation of CuCr{sub 2}O{sub 4}. HTPB propellants containing CuCr{sub 2}O{sub 4} samples were manufactured, then burning rate and mechanical properties have been measured. The results were compared with HTPB propellants containing iron (III) oxide as catalyst. The highest burning rate values were obtained with samples which present a more defined crystalline shape, i.e., the ones synthesized by the coprecipitation method. (authors)

  20. NH3 and urea in the selective catalytic reduction of NOx over oxide-supported copper catalysts

    OpenAIRE

    Sullivan, James A.; Doherty, Julie A.

    2005-01-01

    The temperature-programmed activity of a series of oxide-supported (TiO2, Al2O3 and SiO2) Cu catalysts formed from two different Cu precursors (Cu(NO3)(2) and CuSO4) for the selective catalytic reduction of NOx using solutions of urea as a reductant have been determined. These activities are compared to those found using NH3 as a reducing agent over the same catalysts in the presence of H2O and it is found that catalysts that are active for the selective reduction of NOx with NH3 are inactive...

  1. Nanostructured catalyst supports

    Science.gov (United States)

    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.

  2. A Green Recyclable Poly(4-vinylpyridine)-Supported Copper Iodide Nanoparticles Catalyst for the Multicomponent Synthesis of 3,4-dihydropyrimidin-2(1H)-ones/thiones

    Energy Technology Data Exchange (ETDEWEB)

    Albadi, Jalal [Behbahan Khatam Alanbia Univ. of Technology, Behbahan (Iran, Islamic Republic of); Mansournezhad, Azam; Baghernehad, Mojtba; Frozan, Nasrin [Islamic Azad Univ., Gachsaran (Iran, Islamic Republic of)

    2013-04-15

    Dihydropyrimidone derivatives are important class of compounds that received significant attention from many pharmaceutical and organic chemists because of the broad spectrum of their biological and pharmaceutical properties such as antibacterial, anti-inflammatory, and antivirial properties. The initial synthesis of dihydropyrimidone was reported by Biginelli involving a one pot condensation of an aldehydes, β-ketoester and urea under acidic conditions. However, this reaction suffers from the harsh conditions, long reaction times and low yields of the products. In order to improve the efficiency of this reaction, several modified procedures have been reported. Recently, the application of CuI as the catalyst for the Bignielli reaction have been reported. However, in spite of its application potentials, CuI have some limitations such as thermodynamic instability, long reaction times, non-recyclable, toxicity and difficulty in separation of the product from the reaction medium. Such drawbacks could be obviated by using the supported catalyst. Nitrogen-based polymer have been shown to protect the metal center from oxidation and disproportionation, while enhancing its catalytic activity. To improve the recovery and reuse, copper species have been immobilized on the various supports such as carbon, amine-functionalized polymers, zeolites, amine-functionalized silica and aluminum oxyhydroxide fiber. Poly(4-vinylpyridine)-supported reagents are active for various organic reactions including oxidations, reductions and halogenations. Simple recovery from reaction mixtures, their reusability, compatibility with a wide range of solvents, physical stability, and their toleration of a great number of reaction conditions bodes well for the future of P{sub 4}VPy-supported reagents in which their properties can be finetuned for specific chemical transformations. In recent years, nano-catalysts has emerged as a sustainable and competitive alternative to conventional catalysits

  3. Chitosan-based film supported copper nanoparticles: A potential and reusable catalyst for the reduction of aromatic nitro compounds.

    Science.gov (United States)

    de Souza, Jaqueline F; da Silva, Gabriela T; Fajardo, André R

    2017-04-01

    In this study, copper nanoparticles (CuNPs) were synthesized and stabilized into a chitosan/poly(vinyl alcohol) (CP) based film using a simple protocol under mild conditions. The polymeric matrix utilized in this study allows synthesizing stable nanoparticle with narrow size distribution within the film matrix. Further, this system showed very attractive properties, such as good mechanical properties, chemical resistance, easy handling during use and recovery, relatively low-cost as compared to other similar systems, among others. The catalytic performance of CP-Cu film was tested in the reduction reaction of nitrobenzene (NB) to aniline (AN). Our findings reveal that CP-Cu film catalyzes the reaction efficiently and also decreases the energy of activation (Ea) as compared to other catalysts. The catalytic efficiency of CP-Cu regarding this reaction was kept even after 6 consecutive reuse cycles. All these results rank this novel system as a promising catalyst in the reduction of aromatic nitro compounds to aromatic amines. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Synthesis of supported catalysts

    NARCIS (Netherlands)

    Jong, Krijn P. de

    1999-01-01

    Research reports on the synthesis of supported catalysts during the review period (1997-1998) have shown the use of carbon nanotubes and new hetropolyanions as examples of novel supports and of novel precursors of active components, respectively. Studies of absorption and precipitation chemistry

  5. Synthesis of 2-Substituted Benzofurans from o-Iodophenols and Terminal Alkynes with a Recyclable Palladium Catalyst Supported on Nano-sized Carbon Balls under Copper- and Ligand-Free Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Yum, Eul Kgun; Yang, Okkyung; Kim, Jieun; Park, Hee Jank [Chungnam National Univ., Daejeon (Korea, Republic of)

    2013-09-15

    We have developed a one-step synthesis of benzofurans from o-iodophenol and various terminal alkynes, by using Pd catalyst supported on nano-sized carbon balls (NCB) under copper- and ligand free conditions. This recyclable catalyst could be reused more than 5 times in the same heteroannulation reaction. The results have demonstrated that diverse 2-substituted benzofurans with tolerant functional groups can be prepared simply and conveniently under these conditions.

  6. Combustion synthesis of copper catalysts for selective CO oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, Nielson F.P.; Schmal, Martin [NUCAT/COPPE - UFRJ, Centro de Tecnologia, Bloco G, Sala 128, CEP 21945-970, Rio de Janeiro, RJ (Brazil); Souza, Mariana M.V.M. [NUCAT/COPPE - UFRJ, Centro de Tecnologia, Bloco G, Sala 128, CEP 21945-970, Rio de Janeiro, RJ (Brazil); Escola de Quimica - UFRJ, Centro de Tecnologia, Bloco E, Sala 206, CEP 21941-909, Rio de Janeiro, RJ (Brazil)

    2008-04-15

    Copper catalysts supported on ceria, zirconia and niobia were prepared by combustion method with urea, containing a CuO loading of 6 wt.%, and tested on selective oxidation of CO. The characterization of the samples by X-ray diffraction (XRD) presented the formation of solid solution on CuO-CeO{sub 2} catalyst and a change in crystalline structure of the support with copper insertion on ZrO{sub 2} and Nb{sub 2}O{sub 5} catalysts. The analysis of temperature-programmed reduction (TPR) revealed different interaction degrees of copper with the supports, with reduction peaks between 222 and 390 C. The temperature-programmed desorption of CO (TPD-CO) profiles showed formation of CO{sub 2} and H{sub 2} only for the ceria and zirconia catalysts. In relation to the catalytic tests, the CuO-CeO{sub 2} catalyst presented the best performance, with CO conversion of 95% at 150 C up to 45 h on stream, and CO{sub 2} selectivity of 55%. (author)

  7. Combustion synthesis of copper catalysts for selective CO oxidation

    Science.gov (United States)

    Ribeiro, Nielson F. P.; Souza, Mariana M. V. M.; Schmal, Martin

    Copper catalysts supported on ceria, zirconia and niobia were prepared by combustion method with urea, containing a CuO loading of 6 wt.%, and tested on selective oxidation of CO. The characterization of the samples by X-ray diffraction (XRD) presented the formation of solid solution on CuO-CeO 2 catalyst and a change in crystalline structure of the support with copper insertion on ZrO 2 and Nb 2O 5 catalysts. The analysis of temperature-programmed reduction (TPR) revealed different interaction degrees of copper with the supports, with reduction peaks between 222 and 390 °C. The temperature-programmed desorption of CO (TPD-CO) profiles showed formation of CO 2 and H 2 only for the ceria and zirconia catalysts. In relation to the catalytic tests, the CuO-CeO 2 catalyst presented the best performance, with CO conversion of 95% at 150 °C up to 45 h on stream, and CO 2 selectivity of 55%.

  8. Coating powdered copper catalyst with yttria sol

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Kuan-Ying [Department of Chemical and Engineering and Materials Science, Yuan Ze University, Chung-Li, Taiwan (China); Fuel Cell Center, Yuan Ze University, Chung-Li, Taiwan (China); Shen, Chia-Chieh, E-mail: ccshen@saturn.yzu.edu.tw [Fuel Cell Center, Yuan Ze University, Chung-Li, Taiwan (China); Department of Mechanical Engineering, Yuan Ze University, Chung-Li, Taiwan (China); Graduate School of Renewable Energy Engineering, Yuan Ze University, Chung-Li, Taiwan (China); Lee, Chi-Yuan; Lee, Shuo-Jen [Fuel Cell Center, Yuan Ze University, Chung-Li, Taiwan (China); Department of Mechanical Engineering, Yuan Ze University, Chung-Li, Taiwan (China); Graduate School of Renewable Energy Engineering, Yuan Ze University, Chung-Li, Taiwan (China); Leu, Chih-Hsing [Energy and Environment Research Laboratories, Industrial Technology Research Institute, Hsinchu, Taiwan (China); Wang, Jung-Hui [Fuel Cell Center, Yuan Ze University, Chung-Li, Taiwan (China); Yeh, Chuin-Tih [Department of Chemical and Engineering and Materials Science, Yuan Ze University, Chung-Li, Taiwan (China); Fuel Cell Center, Yuan Ze University, Chung-Li, Taiwan (China)

    2011-07-15

    Research highlights: {yields} The neutral Y{sub 2}O{sub 3} sol is an effective binder for coating powders of CuZnAl catalyst. {yields} A particle size ratio of 15 for catalyst to binder is suggested for stable coating. {yields} Sufficient stirring is an important step in the catalyst slurry preparation. - Abstract: A commercial Y{sub 2}O{sub 3} sol was tested as a binder for coating CuZnAl catalyst powder onto microchannels of a stainless steel plate (SSP). Coated plates were used to fabricate microchannel reactors that generate hydrogen via the steam reforming of methanol (SRM). Washcoating slurries were prepared by suspending catalyst powders into the sol. Slurry parameters, such as solid content, binder content, pH value, and stir time, were optimized to achieve a stable catalyst coating and good SRM performance. The expected stable coating could be obtained from neutral (pH 7) Y{sub 2}O{sub 3} slurry that is required for a negligible dissolution of the copper component of the catalyst. The experimental coating stability generally improved with the slurry stir time. Observed improvements were attributed to a dispersion of catalyst powders in the slurry through a two-step mechanism: the mechanical disassembly of agglomerated CuZnAl powders into primary particles, and the repelling of dissembled particles through adsorption of positively charged Y{sub 2}O{sub 3} binders. A reasonable reaction temperature of 280 deg. C was found for 95% conversion of methanol in SRM from the resulted microchannel reactors. A low CO fraction of 0.3% was also found in the hydrogen-rich gas reformed.

  9. Copper Containing Silicates as Catalysts for Liquid Phase Cyclohexane Oxidation

    Directory of Open Access Journals (Sweden)

    Cruz Rosenira S. da

    2002-01-01

    Full Text Available Copper containing silicates have been prepared by an acid-catalyzed sol-gel process. The materials were characterized by X-ray diffraction and fluorescence, EPR spectroscopy, elemental analysis, N2-physisorption, thermogravimetry, differential scanning calorimetry, temperature-programmed reduction, FTIR and UV/VIS spectroscopy. The silicates were shown to be efficient catalysts for the oxidation of cyclohexane with tert-butyl hydroperoxide as oxidant. Cyclohexanol and cyclohexanone were obtained as the main products. The metal was shown to be weakly bound to the silicate matrix and metal leaching was observed. Leaching was quantified by X-ray fluorescence and leaching tests showed that the catalytic activity is due to supported copper species. Leached copper showed no activity in the homogeneous phase.

  10. ANALYSIS AND DEVELOPMENT OF COPPER RECYCLING OF DEAD COPPER-CONTAINING CATALYSTS

    Directory of Open Access Journals (Sweden)

    O. S. Komarov

    2009-01-01

    Full Text Available The technology of processing of copper-bearing dead catalysts, which includes leaching and deposition of copper by means of electrolysis and also their application in composition of the mixture for alloy doping is offered.

  11. Application of Heterogeneous Copper Catalyst in a Continuous Flow Process: Dehydrogenation of Cyclohexanol

    Science.gov (United States)

    Glin´ski, Marek; Ulkowska, Urszula; Iwanek, Ewa

    2016-01-01

    In this laboratory experiment, the synthesis of a supported solid catalyst (Cu/SiO2) and its application in the dehydrogenation of cyclohexanol performed under flow conditions was studied. The experiment was planned for a group of two or three students for two 6 h long sessions. The copper catalyst was synthesized using incipient wetness…

  12. Nano copper and cobalt ferrites as heterogeneous catalysts for the ...

    Indian Academy of Sciences (India)

    trisubstituted imidazoles using magnetic recyclable spinel nano copper and cobalt ferrites by the condensation of benzil, aromatic aldehyde and ammonium acetate in ethanol as solvent. The reaction, with these catalysts was carried out under mild ...

  13. Theoretical investigations on the structure of copper catalysts at zinc oxide surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Hiller, Bjoern; Behler, Joerg [Lehrstuhl fuer Theoretische Chemie, Ruhr-Universitaet Bochum (Germany)

    2011-07-01

    The Cu rate at ZnO system is an important catalyst, e.g. in methanol synthesis. From experiments it is known that the structure of the copper particles strongly depends on the gas phase composition. In addition there is some evidence for strong interactions between the copper particles and the oxide support. To understand this system it is crucial to investigate the structure of the involved copper surfaces in different gaseous environments and the structure of the interface between the copper particles and the zinc oxide support. Using density-functional theory we determine the relative stabilities of a variety of possible oxygen and hydrogen adsorbate phases on copper surfaces to predict the shape of copper clusters under catalytic conditions. Moreover some results concerning the structure of the interface between copper and zinc oxide are presented.

  14. Copper (0) nanoparticles onto silica: A stable and facile catalyst for ...

    Indian Academy of Sciences (India)

    ... of copper (0)nanoparticles (synthesized through bottom-up approach) on the solid supports such as silica, HAP, cellulose andbasic alumina. Studies comparing these supported catalysts were done with the synthesis of arylmethylene-bis-(3-hydroxy-2-cyclohexene-1-one) via the cascade Knoevenagel/Michael reaction.

  15. The Effect of Copper Addition on the Activity and Stability of Iron-Based CO2 Hydrogenation Catalysts

    Directory of Open Access Journals (Sweden)

    Matthew J. Bradley

    2017-09-01

    Full Text Available Iron-based CO2 catalysts have shown promise as a viable route to the production of olefins from CO2 and H2 gas. However, these catalysts can suffer from low conversion and high methane selectivity, as well as being particularly vulnerable to water produced during the reaction. In an effort to improve both the activity and durability of iron-based catalysts on an alumina support, copper (10–30% has been added to the catalyst matrix. In this paper, the effects of copper addition on the catalyst activity and morphology are examined. The addition of 10% copper significantly increases the CO2 conversion, and decreases methane and carbon monoxide selectivity, without significantly altering the crystallinity and structure of the catalyst itself. The FeCu/K catalysts form an inverse spinel crystal phase that is independent of copper content and a metallic phase that increases in abundance with copper loading (>10% Cu. At higher loadings, copper separates from the iron oxide phase and produces metallic copper as shown by SEM-EDS. An addition of copper appears to increase the rate of the Fischer–Tropsch reaction step, as shown by modeling of the chemical kinetics and the inter- and intra-particle transport of mass and energy.

  16. Catalytic combustion of styrene over copper based catalyst: inhibitory effect of water vapor.

    Science.gov (United States)

    Pan, Hongyan; Xu, Mingyao; Li, Zhong; Huang, Sisi; He, Chun

    2009-07-01

    The effects of water vapor on the activity of the copper based catalysts with different supports such as CuO/gamma-Al2O3, CuO/SiO2 and CuO/TiO2 for styrene combustion were investigated. The catalytic activity of the catalysts was tested in the absence of and presence of water vapor and the catalysts were characterized. Temperature programmed desorption (TPD) experiments and diffuse reflectance infrared fourier transform spectroscopy (DRIFTS) measurements were conducted in order to estimate and explain the water effects. Results showed that the existence of water vapor had a significant negative effect on the catalytic activity of these copper based catalysts due to the competition adsorption of water molecule. DRIFTS studies showed that the catalyst CuO/gamma-Al2O3 had the strongest adsorption of water, while the catalyst CuO/TiO2 had the weakest adsorption of water. H2O-TPD studies also indicated that the order of desorption activation energies of water vapor on the catalysts or the strength of interactions of water molecules with the surfaces of the catalysts was CuO/gamma-Al2O3>CuO/SiO2>CuO/TiO2. As a consequence of that, the CuO/TiO2 exhibited the better durability to water vapor, while CuO/gamma-Al2O3 had the poorest durability to water vapor among these three catalysts.

  17. Review on Copper and Palladium Based Catalysts for Methanol Steam Reforming to Produce Hydrogen

    Directory of Open Access Journals (Sweden)

    Xinhai Xu

    2017-06-01

    Full Text Available Methanol steam reforming is a promising technology for producing hydrogen for onboard fuel cell applications. The methanol conversion rate and the contents of hydrogen, carbon monoxide and carbon dioxide in the reformate, significantly depend on the reforming catalyst. Copper-based catalysts and palladium-based catalysts can effectively convert methanol into hydrogen and carbon dioxide. Copper and palladium-based catalysts with different formulations and compositions have been thoroughly investigated in the literature. This work summarized the development of the two groups of catalysts for methanol steam reforming. Interactions between the activity components and the supports as well as the effects of different promoters were discussed. Compositional and morphological characteristics, along with the methanol steam reforming performances of different Cu/ZnO and Pd/ZnO catalysts promoted by Al2O3, CeO2, ZrO2 or other metal oxides, were reviewed and compared. Moreover, the reaction mechanism of methanol steam reforming over the copper based and palladium based catalysts were discussed.

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

    Science.gov (United States)

    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.

  19. Applications and Preparation Methods of Copper Chromite Catalysts: A Review

    Directory of Open Access Journals (Sweden)

    Ram Prasad

    2011-11-01

    Full Text Available In this review article various applications and preparation methods of copper chromite catalysts have been discussed. While discussing it is concluded that copper chromite is a versatile catalyst which not only catalyses numerous processes of commercial importance and national program related to defence and space research but also finds applications in the most concerned problem worldwide i.e. environmental pollution control. Several other very useful applications of copper chromite catalysts are in production of clean energy, drugs and agro chemicals, etc. Various preparation methods about 15 have been discussed which depicts clear idea about the dependence of catalytic activity and selectivity on way of preparation of catalyst. In view of the globally increasing interest towards copper chromite catalysis, reexamination on the important applications of such catalysts and their useful preparation methods is thus the need of the time. This review paper encloses 369 references including a well-conceivable tabulation of the newer state of the art. Copyright © 2011 by BCREC UNDIP. All rights reserved.(Received: 19th March 2011, Revised: 03rd May 2011, Accepted: 23rd May 2011[How to Cite: R. Prasad, and P. Singh. (2011. Applications and Preparation Methods of Copper Chromite Catalysts: A Review. Bulletin of Chemical Reaction Engineering & Catalysis, 6 (2: 63-113. doi:10.9767/bcrec.6.2.829.63-113][How to Link / DOI: http://dx.doi.org/10.9767/bcrec.6.2.829.63-113 || or local:  http://ejournal.undip.ac.id/index.php/bcrec/article/view/829 ] | View in 

  20. Degradation reaction of Diazo reactive black 5 dye with copper (II) sulfate catalyst in thermolysis treatment.

    Science.gov (United States)

    Lau, Yen-Yie; Wong, Yee-Shian; Ang, Tze-Zhang; Ong, Soon-An; Lutpi, Nabilah Aminah; Ho, Li-Ngee

    2017-12-23

    The theme of present research demonstrates performance of copper (II) sulfate (CuSO 4 ) as catalyst in thermolysis process to treat reactive black 5 (RB 5) dye. During thermolysis without presence of catalyst, heat was converted to thermal energy to break the enthalpy of chemical structure bonding and only 31.62% of color removal. With CuSO 4 support as auxiliary agent, the thermally cleaved molecular structure was further destabilized and reacted with CuSO 4 . Copper ions functioned to delocalize the coordination of π of the lone paired electron in azo bond, C=C bond of the sp 2 carbon to form C-C of the sp 3 amorphous carbon in benzene and naphthalene. Further, the radicals of unpaired electrons were stabilized and RB 5 was thermally decomposed to methyl group. Zeta potential measurement was carried out to analyze the mechanism of RB 5 degradation and measurement at 0 mV verified the critical chemical concentration (CCC) (0.7 g/L copper (II) sulfate), as the maximum 92.30% color removal. The presence of copper (II) sulfate catalyst has remarkably increase the RB 5 dye degradation as the degradation rate constant without catalyst, k 1 is 6.5224 whereas the degradation rate constant with catalyst, k 2 is 25.6810. This revealed the correlation of conversion of thermal energy from heat to break the chemical bond strength, subsequent fragmentation of RB 5 dye molecular mediated by copper (II) sulfate catalyst. The novel framework on thermolysis degradation of molecular structure of RB 5 with respect to the bond enthalpy and interfacial intermediates decomposition with catalyst reaction were determined.

  1. Oxidation catalysts on alkaline earth supports

    Science.gov (United States)

    Mohajeri, Nahid

    2017-03-21

    An oxidation catalyst includes a support including particles of an alkaline earth salt, and first particles including a palladium compound on the support. The oxidation catalyst can also include precious metal group (PMG) metal particles in addition to the first particles intermixed together on the support. A gas permeable polymer that provides a continuous phase can completely encapsulate the particles and the support. The oxidation catalyst may be used as a gas sensor, where the first particles are chemochromic particles.

  2. Evaluation of nickel and copper catalysts in biogas reforming for hydrogen production in SOFC

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Leonardo Alves; Martins, Andre Rosa; Rangel, Maria do Carmo, E-mail: mcarmov@ufba.br [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Grupo de Estudos em Cinetica e Catalise; Ballarini, Adriana; Maina, Silvia [Instituto de Investigaciones en Catalisis Y Petroquimica Ing. Jose Miguel Parera (INCAPE), Santa Fe (Argentina)

    2017-01-15

    The solid oxide fuel cells (SOFC) enable the efficient generation of clean energy, fitting the current requirements of the growing demand for electricity and for the environment preservation. When powered with biogas (from digesters of municipal wastes), the SOFCs also contribute to reduce the environmental impact of these wastes. The most suitable route to produce hydrogen inside SOFC from biogas is through dry reforming but the catalyst is easily deactivated by coke, because of the high amounts of carbon in the stream. A promising way to overcome this drawback is by adding a second metal to nickel-based catalysts. Aiming to obtain active, selective and stable catalysts for biogas dry reforming, solids based on nickel (15%) and copper (5%) supported on aluminum and magnesium oxide were studied in this work. Samples were prepared by impregnating the support with nickel and copper nitrate, followed by calcination at 500, 600 and 800 deg C. It was noted that all solids were made of nickel oxide, nickel aluminate and magnesium aluminate but no copper compound was found. The specific surface areas did not changed with calcination temperature but the nickel oxide average particles size increased. The solids reducibility decreased with increasing temperature. All catalysts were active in methane dry reforming, leading to similar conversions but different selectivities to hydrogen and different activities in water gas shift reaction (WGSR). This behavior was assigned to different interactions between nickel and copper, at different calcination temperatures. All catalysts were active in WGSR, decreasing the hydrogen to carbon monoxide molar ratio and producing water. The catalyst calcined at 500 deg C was the most promising one, leading to the highest hydrogen yield, besides the advantage of being produced at the lowest calcination temperature, requiring less energy in its preparation. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Jernigan, Glenn Geoffrey [California Univ., Berkeley, CA (United States). Dept. of Chemistry

    1994-10-01

    Carbon monoxide oxidation was performed over the three different oxidation states of copper -- metallic (Cu), copper (I) oxide (Cu2O), and copper (II) oxide (CuO) as a test case for developing a model metal oxide catalyst amenable to study by the methods of modern surface science and catalysis. Copper was deposited and oxidized on oxidized supports of aluminum, silicon, molybdenum, tantalum, stainless steel, and iron as well as on graphite. The catalytic activity was found to decrease with increasing oxidation state (Cu > Cu2O > CuO) and the activation energy increased with increasing oxidation state (Cu, 9 kcal/mol < Cu2O, 14 kcal/mol < CuO, 17 kcal/mol). Reaction mechanisms were determined for the different oxidation states. Lastly, NO reduction by CO was studied. A Cu and CuO catalyst were exposed to an equal mixture of CO and NO at 300--350 C to observe the production of N2 and CO2. At the end of each reaction, the catalyst was found to be Cu2O. There is a need to study the kinetics of this reaction over the different oxidation states of copper.

  4. Catalyst support structure, catalyst including the structure, reactor including a catalyst, and methods of forming same

    Science.gov (United States)

    Van Norman, Staci A.; Aston, Victoria J.; Weimer, Alan W.

    2017-05-09

    Structures, catalysts, and reactors suitable for use for a variety of applications, including gas-to-liquid and coal-to-liquid processes and methods of forming the structures, catalysts, and reactors are disclosed. The catalyst material can be deposited onto an inner wall of a microtubular reactor and/or onto porous tungsten support structures using atomic layer deposition techniques.

  5. Mordenite - Type Zeolite SCR Catalysts with Iron or Copper

    DEFF Research Database (Denmark)

    2012-01-01

    much higher alkali resistivity than that of commercial V2O5/WO3-TiO2 (VWT) SCR catalyst which is currently used for NOx abatement in stationary installations. Unique support properties like high surface area and surface acidity, which are not available in the commercial VWT catalyst, seem...

  6. Review on Copper and Palladium Based Catalysts for Methanol Steam Reforming to Produce Hydrogen

    OpenAIRE

    Xinhai Xu; Kaipeng Shuai; Ben Xu

    2017-01-01

    Methanol steam reforming is a promising technology for producing hydrogen for onboard fuel cell applications. The methanol conversion rate and the contents of hydrogen, carbon monoxide and carbon dioxide in the reformate, significantly depend on the reforming catalyst. Copper-based catalysts and palladium-based catalysts can effectively convert methanol into hydrogen and carbon dioxide. Copper and palladium-based catalysts with different formulations and compositions have been thoroughly inve...

  7. Magnetic Silica Supported Copper: A Modular Approach to Aqueous Ullmann-type Amination of Aryl Halides

    Science.gov (United States)

    One-pot synthesis of magnetic silica supported copper catalyst has been described via in situ generated magnetic silica (Fe3O4@SiO2); the catalyst can be used for the efficacious amination of aryl halides in aqueous medium under microwave irradiation.

  8. Impeded solid state reactions and transformations in ceramic catalysts supports and catalysts

    Directory of Open Access Journals (Sweden)

    Ernő E. Kiss

    2012-12-01

    Full Text Available Impeded chemical reactions and impeded polymorphous transformation in materials are discussed, as desired effects, for stabilization of ceramic catalyst supports and ceramic based catalysts. This paper gives a short overview about the possibilities of slowing down the aging processes in ceramic catalyst supports and catalysts. Special attention is given to alumina and titania based catalysts.

  9. Raney copper catalysts for the water-gas shift reaction - II. Initial catalyst optimisation

    CSIR Research Space (South Africa)

    Mellor, JR

    1997-12-23

    Full Text Available -Zn-A1 catalyst. During the controlled passivation Table 2 Crystalline phase of alloys B, C and D and their product Raney copper catalysts before and after reaction Alloy Precursor alloy phases Cat. phases before reaction a Cat. phases after reaction a... L; dry gas composition=10% CO/90% N2; CO : H20=I : 22.5; catalyst volume=2i0.1 ml): (O)=Cat. A Cu(69.3)Zn(6.9)Al( 19.5); (~)=cat. B Cu(73.6)Zn(10.9)AI(14.8); (W1)=cat. C Cu(72.4)Zn(13.3)Al(12.9); ({))=cat. D Cu(61.5)Zn(15.1)AI(19.1). It can...

  10. Effects of Cu over Pd based catalysts supported on silica or niobia

    Directory of Open Access Journals (Sweden)

    Roma M.N.S.C.

    2000-01-01

    Full Text Available Palladium and palladium-copper catalysts supported on silica and niobia were characterized by H2 chemisorption and H2-O2 titration. Systems over silica were also analyzed by transmission electron microscopy and EXAFS. The metallic dispersion decreased from 20% to 7% when the content of Pd was increased from 0.5wt.-% to 3wt.-% in monometallic catalysts. The addition of 3 wt.-% Cu to obtain Pd-Cu catalysts caused a remarkable capacity loss of hydrogen chemisorption. TPR analysis suggested an interaction between the two metals and EXAFS characterization of the catalyst supported on silica confirmed the formation of Pd-Cu alloy. Pd/Nb2O5 catalysts showed turnover numbers higher than those obtained with the Pd/SiO2 systems in the cyclohexane dehydrogenation. However, the bimetallic catalysts showed very low turnover numbers.

  11. Polypropylene obtained through zeolite supported catalysts

    Directory of Open Access Journals (Sweden)

    Queli C. Bastos

    2004-01-01

    Full Text Available Propylene polymerizations were carried out with f2C(Flu(CpZrCl2 and SiMe2(Ind2ZrCl2 catalysts supported on silica, zeolite sodic mordenite (NaM and acid mordenite (HM. The polymerizations were performed at different temperatures and varying aluminium/zirconium molar ratios ([Al]/[Zr]. The effect of these reaction parameters on the catalyst activity was investigated using a proposed statistical experimental planning. In the case of f2C(Flu(CpZrCl2, SiO2 and NaM were used as support and the catalyst performance evaluated using toluene and pentane as polymerization solvent. The molecular weight, molecular weight distribution, melting point and crystallinity of the polymers were examined. The results indicate very high activities for the syndiospecific heterogeneous system. Also, the polymers obtained had superior Mw and stereoregularity.

  12. Attrition resistant gamma-alumina catalyst support

    Science.gov (United States)

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

    2006-03-14

    A .gamma.-alumina catalyst support having improved attrition resistance produced by a method comprising the steps of treating a particulate .gamma.-alumina material with an acidic aqueous solution comprising water and nitric acid and then, prior to adding any catalytic material thereto, calcining the treated .gamma.-alumina.

  13. Iron Oxide-Supported Copper Oxide Nanoparticles (Nanocat-Fe-CuO): Magnetically Recyclable Catalysts for the Synthesis of Pyrazole Derivatives, 4-Methoxyaniline, and Ullmann-type Condensation Reactions

    Science.gov (United States)

    An efficient and benign protocol is reported for the synthesis of 4-methoxyaniline, medicinally important pyrazole derivatives, and Ullmann-type condensation reaction using magnetically separable and reusable magnetite-supported copper (nanocat-Fe-CuO) nanoparticles under mild co...

  14. Effect of copper loading on copper-ceria catalysts performance in CO selective oxidation for fuel cell applications

    Energy Technology Data Exchange (ETDEWEB)

    Ayastuy, J.L.; Gurbani, A.; Gonzalez-Marcos, M.P.; Gutierrez-Ortiz, M.A. [Departamento de Ingenieria Quimica, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco/EHU, E-48080 Bilbao (Spain); Unidad Asociada ' ' Tecnologias Quimicas para la Sostenibilidad Ambiental' ' , CSIC-UPV/EHU (Spain)

    2010-02-15

    Copper-ceria catalysts with three different Cu loadings (1, 7 and 15 wt%) were prepared by incipient wet impregnation, dried at 120 C and calcined in air at 500 C. The as-prepared catalysts were characterized by XRD, BET, Diffuse Reflectance Spectroscopy (DRS-UV-visible), Raman spectroscopy, CO and H{sub 2}-TPR, CO-TPR, CO-TPD and Oxygen Storage Capacity (OSC) measurements (with CO and O{sub 2} concentration step-changes). The results indicated a good dispersion of copper for catalysts with 1 and 7 wt% Cu; however, bulk CuO was present for catalyst with 15 wt% Cu loading. Catalyst with 7 wt% Cu was observed to have very high capacity to release lattice oxygen to oxidize CO at low temperature. Activity results for CO oxidation in the absence and in the presence of 60% H{sub 2}, demonstrated a very similar performance for catalysts with 7 and 15 wt% Cu (both with T{sub 100} = 112 C), and much better than that of catalyst loaded with 1 wt% Cu. Catalyst with 7 wt% of copper shows very high activity (100% in a wide temperature window) and selectivity (higher than 85%), which makes an attractive for its use in purification of hydrogen for fuel cell applications. The presence of a mixture of CO{sub 2} and H{sub 2}O inhibited catalyst activity, with CuO/CeO{sub 2} catalyst with 7 wt% Cu exhibiting the best performance in the overall reaction temperature range. This could be attributed to the presence of highly disperse copper, only part of it in deep interaction with ceria. The effect of O{sub 2}/CO ratio ({lambda}) and the potential reversibility of the inhibitory effect of CO{sub 2} and H{sub 2}O were also investigated. (author)

  15. Performance evaluation of commercial copper chromites as burning rate catalyst for solid propellants

    Directory of Open Access Journals (Sweden)

    Milton Faria Diniz

    2010-09-01

    Full Text Available Copper chromites are well known as burning rate catalysts for the combustion of composite solid propellants, used as a source of energy for rocket propulsion. The propellant burning rate depends upon the catalyst characteristics such as chemical composition and specific surface area. In this work, copper chromite samples from different suppliers were characterized by chemical analysis, FT-IR spectroscopy and by surface area measurement (BET. The samples were then evaluated as burning rate catalyst in a typical composite propellant formulation based on HTPB binder, ammonium perchlorate and aluminum. The obtained surface area values are very close to those informed by the catalyst suppliers. The propellant processing as well as its mechanical properties were not substantially affected by the type of catalyst. Some copper chromite catalysts caused an increase in the propellant burning rate in comparison to the iron oxide catalyst. The results show that in addition to the surface area, other parameters like chemical composition, crystalline structure and the presence of impurities might be affecting the catalyst performance. All evaluated copper chromite samples may be used as burning rate catalyst in composite solid propellant formulations, with slight advantages for the SX14, Cu-0202P and Cu-1800P samples, which led to the highest burning rate propellants.

  16. Novel Mesoporous Carbon Supports for PEMFC Catalysts

    Directory of Open Access Journals (Sweden)

    Dustin Banham

    2015-06-01

    Full Text Available Over the past decade; a significant amount of research has been performed on novel carbon supports for use in proton exchange membrane fuel cells (PEMFCs. Specifically, carbon nanotubes, ordered mesoporous carbon, and colloid imprinted carbons have shown great promise for improving the activity and/or stability of Pt-based nanoparticle catalysts. In this work, a brief overview of these materials is given, followed by an in-depth discussion of our recent work highlighting the importance of carbon wall thickness when designing novel carbon supports for PEMFC applications. Four colloid imprinted carbons (CICs were synthesized using a silica colloid imprinting method, with the resulting CICs having pores of 15 (CIC-15, 26 (CIC-26, 50 (CIC-50 and 80 (CIC-80 nm. These four CICs were loaded with 10 wt. % Pt and then evaluated as oxygen reduction (ORR catalysts for use in proton exchange membrane fuel cells. To gain insight into the poorer performance of Pt/CIC-26 vs. the other three Pt/CICs, TEM tomography was performed, indicating that CIC-26 had much thinner walls (0–3 nm than the other CICs and resulting in a higher resistance (leading to distributed potentials through the catalyst layer during operation. This explanation for the poorer performance of Pt/CIC-26 was supported by theoretical calculations, suggesting that the internal wall thickness of these nanoporous CICs is critical to the future design of porous carbon supports.

  17. Reversible-Deactivation Radical Polymerization of Methyl Methacrylate Induced by Photochemical Reduction of Various Copper Catalysts

    Directory of Open Access Journals (Sweden)

    Jaroslav Mosnáček

    2014-11-01

    Full Text Available Photochemically mediated reversible-deactivation radical polymerization of methyl methacrylate was successfully performed using 50–400 ppm of various copper compounds such as CuSO4·5H2O, copper acetate, copper triflate and copper acetylacetonate as catalysts. The copper catalysts were reduced in situ by irradiation at wavelengths of 366–546 nm, without using any additional reducing agent. Bromopropionitrile was used as an initiator. The effects of various solvents and the concentration and structure of ligands were investigated. Well-defined polymers were obtained when at least 100 or 200 ppm of any catalyst complexed with excess tris(2-pyridylmethylamine as a ligand was used in dimethyl sulfoxide as a solvent.

  18. Performance evaluation of commercial copper chromites as burning rate catalyst for solid propellants

    OpenAIRE

    Campos,Eunice Aparecida; Rita de Cássia L. Dutra; Rezende, Luis Cláudio; Diniz,Milton Faria; Nawa, Wilma Massae Dio; Iha,Koshun

    2010-01-01

    Abstract: Copper chromites are well known as burning rate catalysts for the combustion of composite solid propellants, used as a source of energy for rocket propulsion. The propellant burning rate depends upon the catalyst characteristics such as chemical composition and specific surface area. In this work, copper chromite samples from different suppliers were characterized by chemical analysis, FT-IR spectroscopy and by surface area measurement (BET). The samples were then evaluated as burni...

  19. Performance evaluation of commercial copper chromites as burning rate catalyst for solid propellants

    OpenAIRE

    Milton Faria Diniz; Eunice Aparecida Campos; Luis Cláudio Rezende; Rita de Cássia L. Dutra; Wilma Massae Dio Nawa; Koshun Iha

    2010-01-01

    Copper chromites are well known as burning rate catalysts for the combustion of composite solid propellants, used as a source of energy for rocket propulsion. The propellant burning rate depends upon the catalyst characteristics such as chemical composition and specific surface area. In this work, copper chromite samples from different suppliers were characterized by chemical analysis, FT-IR spectroscopy and by surface area measurement (BET). The samples were then evaluated as burning rate ca...

  20. Structural Characteristics of Bimetallic Catalysts Supported on Nano-Ceria

    Directory of Open Access Journals (Sweden)

    J. F. Bozeman

    2011-01-01

    Full Text Available Cu-Pt bimetal catalysts supported on nanocrystalline CeO2 (nano-ceria are synthesized via the low-cost sol-gel approach followed by impregnation processing. The average particle size of the catalytic composites is 63 nm. Ceria nanopowders sequentially impregnated in copper solution and then in Pt solution transformed into Pt-skin-structured Cu-Pt/ceria nanocomposite, based on the surface elemental and bulk compositional analyses. The ceria supporter has a fluorite structure, but the structure of Cu and Pt catalytic contents, not detected by X-ray diffraction spectroscopy due to the low loading level, is yet conclusive. The bimetallic catalytic nanocomposites may potentially serve as sulfur-tolerant anode in solid oxide fuel cells.

  1. Nano copper ferrite: A reusable catalyst for the synthesis of β, γ ...

    Indian Academy of Sciences (India)

    Nano copper ferrite; heterogeneous initiator; allylation; β, γ-unsaturated ketones; reusability. 1. Introduction. Despite the advantages of homogeneous metal catalysts, difficulties in recovering the catalyst from the reaction mixture severely inhibit their use in industry. Heteroge- neous catalysis results in easy separation and ...

  2. A delafossite-based copper catalyst for sustainable Cl2 production by HCl oxidation.

    Science.gov (United States)

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

    2011-07-07

    A copper catalyst based on a delafossite precursor (CuAlO(2)) displays high activity and extraordinary lifetime in the gas-phase oxidation of HCl to Cl(2), representing a cost-effective alternative to RuO(2)-based catalysts for chlorine recycling. This journal is © The Royal Society of Chemistry 2011

  3. Copper on Chitosan: A Recyclable Heterogeneous Catalyst for Azide-alkyne Cycloaddition Reactions in Water

    Science.gov (United States)

    Copper sulfate is immobilized over chitosan by simply stirring an aqueous suspension of chitosan in water with copper sulfate; the ensuing catalyst has been utilized for the azide-alkyne cycloaddition in aqueous media and it can be recycled and reused many time without loosing it...

  4. DeNOx Abatement Modelling over Sonically Prepared Copper USY and ZSM5 Structured Catalysts

    Directory of Open Access Journals (Sweden)

    Przemysław J. Jodłowski

    2017-07-01

    Full Text Available Metallic supports play an important role as structured reactor internals. Due to their specific properties including enhanced heat and mass transport, high mechanical resistivity and elimination of local hot-spots, they are commonly used in gas exhaust abatement from stationary and automotive industries. In this study, the performance of three structured supports with deposited Cu/USY (Ultrastabilised Y—zeolite for deNOx abatement were modelled. Based on kinetic and flow resistance experimental results, the one-dimensional (1D model of structured reactor was developed. The performance of the structured reactors was compared by the length of the reactor necessary to achieve an arbitrary 90% NOx conversion. The performed simulations showed that the sonochemically prepared copper USY and ZSM-5 zeolites deposited on metallic supports may be successfully used as catalysts for deNOx process.

  5. Attrition resistant Fischer-Tropsch catalyst and support

    Science.gov (United States)

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

    2004-05-25

    A catalyst support having improved attrition resistance and a catalyst produced therefrom. The catalyst support is produced by a method comprising the step of treating calcined .gamma.-alumina having no catalytic material added thereto with an acidic aqueous solution having an acidity level effective for increasing the attrition resistance of the calcined .gamma.-alumina.

  6. Decomposition kinetics of ammonia in gaseous stream by a nanoscale copper-cerium bimetallic catalyst.

    Science.gov (United States)

    Hung, Chang-Mao

    2008-01-15

    This study performance is to examine the kinetics over nanoscale copper-cerium bimetallic catalyst under selective catalytic oxidation (SCO) of ammonia to N(2) in a tubular fixed-bed reactor (TFBR) at temperatures from 150 to 400 degrees C in the presence of oxygen. The nanoscale copper-cerium bimetallic catalyst was prepared by co-precipitation with Cu(NO(3))(2) and Ce(NO(3))(3) at molar ratio of 6:4. Experimental results showed that the catalyst with transmission electron microscopy (TEM) revealed that copper and cerium are well dispersed and catalyst in the form of nanometer-sized particles. Moreover, the kinetic behavior of NH(3) oxidation with catalysis can be accounted by using the rate expression of the Langmuir-Hinshelwood type kinetic model. Kinetic parameters are also developed on the basis of the differential reactor data. Also, experimental results are compared with those of the model predicted.

  7. Hydrogen recombiner catalyst test supporting data

    Energy Technology Data Exchange (ETDEWEB)

    Britton, M.D.

    1995-01-19

    This is a data package supporting the Hydrogen Recombiner Catalyst Performance and Carbon Monoxide Sorption Capacity Test Report, WHC-SD-WM-TRP-211, Rev 0. This report contains 10 appendices which consist of the following: Mass spectrometer analysis reports: HRC samples 93-001 through 93-157; Gas spectrometry analysis reports: HRC samples 93-141 through 93-658; Mass spectrometer procedure PNL-MA-299 ALO-284; Alternate analytical method for ammonia and water vapor; Sample log sheets; Job Safety analysis; Certificate of mixture analysis for feed gases; Flow controller calibration check; Westinghouse Standards Laboratory report on Bois flow calibrator; and Sorption capacity test data, tables, and graphs.

  8. Functionalized Graphitic Supports for Improved Fuel Cell Catalyst Stability Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Physical Sciences Inc. (PSI) together with the University of Connecticut (UCONN) proposes to demonstrate the improved fuel cell catalyst support durability offered...

  9. An attempt to selectively oxidize methane over supported gold catalysts

    NARCIS (Netherlands)

    Hereijgers, B.P.C.; Weckhuysen, B.M.

    2011-01-01

    The potential of supported gold catalysts for the selective gas-phase oxidation of methane to methanol with molecular oxygen was investigated. A broad range of supported gold-based catalyst materials was synthesized using reducible and non-reducible support materials. Although the formation of small

  10. DWPF coupled feed flowsheet material balance with batch one sludge and copper nitrate catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Choi, A.S.

    1993-09-28

    The SRTC has formally transmitted a recommendation to DWPF to replace copper formate with copper nitrate as the catalyst form during precipitate hydrolysis [1]. The SRTC was subsequently requested to formally document the technical bases for the recommendation. A memorandum was issued on August 23, 1993 detailing the activities (and responsible individuals) necessary to address the impact of this change in catalyst form on process compatibility, safety, processibility environmental impact and product glass quality [2]. One of the activities identified was the preparation of a material balance in which copper nitrate is substituted for copper formate and the identification of key comparisons between this material balance and the current Batch 1 sludge -- Late Wash material balance [3].

  11. Ni Catalysts Supported on Modified Alumina for Diesel Steam Reforming

    Directory of Open Access Journals (Sweden)

    Antonios Tribalis

    2016-01-01

    Full Text Available Nickel catalysts are the most popular for steam reforming, however, they have a number of drawbacks, such as high propensity toward coke formation and intolerance to sulfur. In an effort to improve their behavior, a series of Ni-catalysts supported on pure and La-, Ba-, (La+Ba- and Ce-doped γ-alumina has been prepared. The doped supports and the catalysts have been extensively characterized. The catalysts performance was evaluated for steam reforming of n-hexadecane pure or doped with dibenzothiophene as surrogate for sulphur-free or commercial diesel, respectively. The undoped catalyst lost its activity after 1.5 h on stream. Doping of the support with La improved the initial catalyst activity. However, this catalyst was completely deactivated after 2 h on stream. Doping with Ba or La+Ba improved the stability of the catalysts. This improvement is attributed to the increase of the dispersion of the nickel phase, the decrease of the support acidity and the increase of Ni-phase reducibility. The best catalyst of the series doped with La+Ba proved to be sulphur tolerant and stable for more than 160 h on stream. Doping of the support with Ce also improved the catalytic performance of the corresponding catalyst, but more work is needed to explain this behavior.

  12. Ligand effect in enantioselective hydrogenation on skeletal copper-palladium catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Vedenyapin, A.A.; Kuznetsova, T.I.; Klabunovskii, E.I.

    1987-08-10

    In the continuation of the study of the capacity of skeletal Cu-Pd catalysts modified with RR-tartaric acid and containing no more than 5 at.% Pd, to conduct enantioselective hydrogenation of ethylacetoacetate (EAA) into R-ethyl-..beta..-hydroxybutyrate (R-EHB), they studied this phenomenon in more detail and made the previously obtained data more precise. Pronounced synergism of the asymmetric effect of chiral copper-palladium catalysts related to manifestation of a ligand effect was found.

  13. CO methanation over supported bimetallic Ni-Fe catalysts: From computational studies towards catalyst optimization

    DEFF Research Database (Denmark)

    Kustov, Arkadii; Frey, Anne Mette; Larsen, Kasper Emil

    2007-01-01

    200-300 degrees C, and characterized using elemental analysis, N-2 physisorption measurements, XRD and TEM. Optimization of the catalyst performance was made by varying the Ni:Fe ratio, the total metal loading and the support material. For both support materials, the bimetallic catalysts...

  14. Nano copper ferrite: A reusable catalyst for the synthesis of , ...

    Indian Academy of Sciences (India)

    Copper ferrite nano material as reusable heterogeneous initiator in the synthesis of , -unsaturated ketones and allylation to acid chlorides are presented. The reaction of allylichalides with various acid chlorides is achieved in the presence of copper ferrite nano powders at room temperature in tetrahydrofuran (THF).

  15. In situ studies on the structure of copper oxide/zinc oxide catalysts.

    Science.gov (United States)

    Günter, M M; Bems, B; Schlögl, R; Ressler, T

    2001-03-01

    Cu/ZnO supported on alumina is a well-known catalyst for steam reforming of methanol. In this work it is attempted to assess the influence of elemental composition on the resulting active copper phase. XAFS measurements of calcined precursors were carried out at the Cu K edge and the Zn K edge. Corresponding RDF show that both copper oxide and zinc oxide exhibit considerable deviations from a linear dependence of their structure on the composition coinciding with changes in phase composition of hydroxycarbonate precursor. From time-resolved in situ experiments at the Cu K edge the degree of reduction can be monitored using a combination of factor analysis (PCA) and least-squares XANES fitting with suitable reference spectra (e.g. Cu metal, Cu2O, and CuO). It is shown that Cu2O forms prior to Cu. The extent of reduction to Cu exhibited a typical nucleation growth behavior with an enhanced reaction rate for more diluted samples. Adding oxygen to the feed gas leads to the formation of mixed Cu2+ and Cu+ phases accompanied by a complete loss of activity in methanol steam reforming. After switching back to steam reforming conditions the activity is regained.

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

    Science.gov (United States)

    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.

  17. Graphitic Carbon Nitride Supported Catalysts for Polymer Electrolyte Fuel Cells

    Science.gov (United States)

    2014-01-01

    Graphitic carbon nitrides are investigated for developing highly durable Pt electrocatalyst supports for polymer electrolyte fuel cells (PEFCs). Three different graphitic carbon nitride materials were synthesized with the aim to address the effect of crystallinity, porosity, and composition on the catalyst support properties: polymeric carbon nitride (gCNM), poly(triazine) imide carbon nitride (PTI/Li+Cl–), and boron-doped graphitic carbon nitride (B-gCNM). Following accelerated corrosion testing, all graphitic carbon nitride materials are found to be more electrochemically stable compared to conventional carbon black (Vulcan XC-72R) with B-gCNM support showing the best stability. For the supported catalysts, Pt/PTI-Li+Cl– catalyst exhibits better durability with only 19% electrochemical surface area (ECSA) loss versus 36% for Pt/Vulcan after 2000 scans. Superior methanol oxidation activity is observed for all graphitic carbon nitride supported Pt catalysts on the basis of the catalyst ECSA. PMID:24748912

  18. Olefin polymerization over supported chromium oxide catalysts

    NARCIS (Netherlands)

    Weckhuysen, B.M.; Schoonheydt, R.A.

    1999-01-01

    Cr/SiO2 or Phillips-type catalysts are nowadays responsible for a large fraction of all polyethylene (HDPE and LLDPE) worldwide produced. In this review, several key-properties of Cr/SiO2 catalysts will be discussed in relation to their polymerization characteristics. It will be shown how the

  19. Silver(I) and copper(II)-imidazolium carboxylates: Efficient catalysts ...

    Indian Academy of Sciences (India)

    GANESAN PRABUSANKAR

    Copper(II); Silver(I); Coordination polymer; Imidazolium ion; Ullmann coupling. 1. ... dination polymers. These newly prepared catalysts are highly active towards Ullmann reaction. 2. Experimental. 2.1 Materials and methods. The solvents were purchased from commercial ..... The thermal stability of 1 and 2 was analysed.

  20. Investigating Catalyst-Support Interactions To Improve the Hydrogen Evolution Reaction Activity of Thiomolybdate [Mo3S13](2-) Nanoclusters

    DEFF Research Database (Denmark)

    Hellstern, Thomas R.; Kibsgaard, Jakob; Tsai, Charlie

    2017-01-01

    a structural motif that resembles the active site of MoS2 and has been reported to be among the most active forms of molybdenum sulfide. Herein, we improve the activity of the [Mo3S13](2-) catalysts through catalyst support interactions. We synthesize [Mo3S13](2-) on gold, silver, glassy carbon, and copper...

  1. Fundamental studies of supported bimetallic catalysts by NMR spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Savargaonkar, Nilesh [Iowa State Univ., Ames, IA (United States)

    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.

  2. Titanium dioxide as a catalyst support in heterogeneous catalysis.

    Science.gov (United States)

    Bagheri, Samira; Muhd Julkapli, Nurhidayatullaili; Bee Abd Hamid, Sharifah

    2014-01-01

    The lack of stability is a challenge for most heterogeneous catalysts. During operations, the agglomeration of particles may block the active sites of the catalyst, which is believed to contribute to its instability. Recently, titanium oxide (TiO2) was introduced as an alternative support material for heterogeneous catalyst due to the effect of its high surface area stabilizing the catalysts in its mesoporous structure. TiO2 supported metal catalysts have attracted interest due to TiO2 nanoparticles high activity for various reduction and oxidation reactions at low pressures and temperatures. Furthermore, TiO2 was found to be a good metal oxide catalyst support due to the strong metal support interaction, chemical stability, and acid-base property. The aforementioned properties make heterogeneous TiO2 supported catalysts show a high potential in photocatalyst-related applications, electrodes for wet solar cells, synthesis of fine chemicals, and others. This review focuses on TiO2 as a support material for heterogeneous catalysts and its potential applications.

  3. Titanium Dioxide as a Catalyst Support in Heterogeneous Catalysis

    Science.gov (United States)

    Bagheri, Samira; Muhd Julkapli, Nurhidayatullaili; Bee Abd Hamid, Sharifah

    2014-01-01

    The lack of stability is a challenge for most heterogeneous catalysts. During operations, the agglomeration of particles may block the active sites of the catalyst, which is believed to contribute to its instability. Recently, titanium oxide (TiO2) was introduced as an alternative support material for heterogeneous catalyst due to the effect of its high surface area stabilizing the catalysts in its mesoporous structure. TiO2 supported metal catalysts have attracted interest due to TiO2 nanoparticles high activity for various reduction and oxidation reactions at low pressures and temperatures. Furthermore, TiO2 was found to be a good metal oxide catalyst support due to the strong metal support interaction, chemical stability, and acid-base property. The aforementioned properties make heterogeneous TiO2 supported catalysts show a high potential in photocatalyst-related applications, electrodes for wet solar cells, synthesis of fine chemicals, and others. This review focuses on TiO2 as a support material for heterogeneous catalysts and its potential applications. PMID:25383380

  4. Mesoporous Molecular Sieves as Supports for Metathesis Catalysts

    Science.gov (United States)

    Balcar, Hynek; Cejka, Jirí

    Mesoporous molecular sieves represent a new family of inorganic oxides with regular nanostructure, large surface areas, large void volumes, and narrow pore size distribution of mesopores. These materials offer new possibilities for designing highly active and selective catalysts for olefin metathesis and metathesis polymerization. Siliceous sieves MCM-41, MCM-48, SBA-15, and organized mesoporous alumina (OMA) were used as supports for preparation of new molybdenum and rhenium oxide catalysts, as well as for heterogenization of well-defined homogeneous catalysts.

  5. Electrochemical delamination of CVD-grown graphene film: toward the recyclable use of copper catalyst.

    Science.gov (United States)

    Wang, Yu; Zheng, Yi; Xu, Xiangfan; Dubuisson, Emilie; Bao, Qiaoliang; Lu, Jiong; Loh, Kian Ping

    2011-12-27

    The separation of chemical vapor deposited (CVD) graphene from the metallic catalyst it is grown on, followed by a subsequent transfer to a dielectric substrate, is currently the adopted method for device fabrication. Most transfer techniques use a chemical etching method to dissolve the metal catalysts, thus imposing high material cost in large-scale fabrication. Here, we demonstrate a highly efficient, nondestructive electrochemical route for the delamination of CVD graphene film from metal surfaces. The electrochemically delaminated graphene films are continuous over 95% of the surface and exhibit increasingly better electronic quality after several growth cycles on the reused copper catalyst, due to the suppression of quasi-periodical nanoripples induced by copper step edges. The electrochemical delamination process affords the advantages of high efficiency, low-cost recyclability, and minimal use of etching chemicals.

  6. Supported Molten Metal Catalysis. A New Class of Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Ravindra Datta; Ajeet Singh; Manuela Serban; Istvan Halasz

    2006-06-02

    We describe a new class of heterogeneous catalysts called supported molten metal catalysis (SMMC), in which molten metal catalysts are dispersed as nanodroplets on the surface of porous supports, allowing much larger active surface area than is possible in conventional contacting techniques for catalytic metals that are molten under reaction conditions, thus greatly enhancing their activity and potential utility. Specific examples of different types of reactions are provided to demonstrate the broad applicability of the technique in designing active, selective, and stable new catalysts. It is shown that dispersing the molten metal on a support in the suggested manner can enhance the rate of a reaction by three to four orders of magnitude as a result of the concomitant increase in the active surface area. New reaction examples include {gamma}-Al{sub 2}O{sub 3} supported molten Te (melting point 450 C) and Ga (MP 30 C) catalysts for bifunctional methylcyclohexane dehydrogenation. These catalysts provide activity similar to conventional Pt-based catalysts for this with better resistance to coking. In addition, results are described for a controlled pore glass supported molten In (MP 157 C) catalyst for the selective catalytic reduction of NO with ethanol in the presence of water, demonstrating activities superior to conventional catalysts for this reaction. A discussion is also provided on the characterization of the active surface area and dispersion of these novel supported catalysts. It is clear based on the results described that the development of new active and selective supported molten metal catalysts for practical applications is entirely plausible.

  7. Synthesis and characterization of MCM-41-supported nano zirconia catalysts

    Directory of Open Access Journals (Sweden)

    Mohamed S. Abdel Salam

    2015-03-01

    Full Text Available Series of MCM-41 supported sulfated Zirconia (SZ catalysts with different loadings (2.5–7.5% wt. were prepared using direct impregnation method. The acquired solid catalysts were characterized structurally and chemically using X-RD, HRTEM, BET, FT-IR, Raman spectroscopy and TPD analysis. The acidity of the solid catalysts was investigated through cumene cracking and isopropanol dehydration at different temperatures. As the SZ loading increases, the surface acidity of the mesoporous catalysts was enhanced, this was reflected by the higher catalytic activity toward cumene cracking and isopropanol dehydration.

  8. Silica-supported Preyssler Nanoparticles as New Catalysts in the ...

    African Journals Online (AJOL)

    A new and efficient method for the preparation of 4(3H)-quinazolinones from the condensation of anthranilic acid, orthoester and substituted anilines, in the presence of catalytic amounts of silica-supported Preyssler nanoparticles is reported. The catalyst performs very well in comparison with other catalysts reported before.

  9. Supported organometallic catalysts for hydrogenation and Olefin Polymerization

    Science.gov (United States)

    Marks, Tobin J.; Ahn, Hongsang

    2001-01-01

    Novel heterogeneous catalysts for the which hydrogenation of olefins and arenes with high conversion rates under ambient conditions and the polymerization of olefins have been developed. The catalysts are synthesized from Ziegler-type precatalysts by supporting them on sulfate-modified zirconia.

  10. Copper slag as a catalyst for mercury oxidation in coal combustion flue gas.

    Science.gov (United States)

    Li, Hailong; Zhang, Weilin; Wang, Jun; Yang, Zequn; Li, Liqing; Shih, Kaimin

    2017-12-08

    Copper slag is a byproduct of the pyrometallurgical smelting of copper concentrate. It was used in this study to catalyze elemental mercury (Hg0) oxidation in simulated coal combustion flue gas. The copper slag exhibited excellent catalytic performance in Hg0 oxidation at temperatures between 200 °C and 300 °C. At the most optimal temperature of 250 °C, a Hg0 oxidation efficiency of 93.8% was achieved under simulated coal combustion flue gas with both a high Hg0 concentration and a high gas hourly space velocity of 128,000 h-1. Hydrogen chloride (HCl) was the flue gas component responsible for Hg0 oxidation over the copper slag. The transition metal oxides, including iron oxides and copper oxide in the copper slag, exhibited significant catalytic activities in the surface-mediated oxidation of Hg0 in the presence of HCl. It is proposed that the Hg0 oxidation over the copper slag followed the Langmuir-Hinshelwood mechanism whereby reactive chlorine species that originated from HCl reacted with the physically adsorbed Hg0 to form oxidized mercury. This study demonstrated the possibility of reusing copper slag as a catalyst for Hg0 oxidation and revealed the mechanisms involved in the process and the key factors in the performance. This knowledge has fundamental importance in simultaneously reducing industrial waste and controlling mercury emissions from coal-fired power plants. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Attrition Resistant Fischer-Tropsch Catalysts Based on FCC Supports

    Energy Technology Data Exchange (ETDEWEB)

    Adeyiga, Adeyinka

    2010-02-05

    Commercial spent fluid catalytic cracking (FCC) catalysts provided by Engelhard and Albemarle were used as supports for Fe-based catalysts with the goal of improving the attrition resistance of typical F-T catalysts. Catalysts with the Ruhrchemie composition (100 Fe/5 Cu/4.2 K/25 spent FCC on mass basis) were prepared by wet impregnation. XRD and XANES analysis showed the presence of Fe{sub 2}O{sub 3} in calcined catalysts. FeC{sub x} and Fe{sub 3}O{sub 4} were present in the activated catalysts. The metal composition of the catalysts was analyzed by ICP-MS. F-T activity of the catalysts activated in situ in CO at the same conditions as used prior to the attrition tests was measured using a fixed bed reactor at T = 573 K, P = 1.38 MPa and H{sub 2}:CO ratio of 0.67. Cu and K promoted Fe supported over Engelhard provided spent FCC catalyst shows relatively good attrition resistance (8.2 wt% fines lost), high CO conversion (81%) and C{sub 5}+ hydrocarbons selectivity (18.3%).

  12. Hydrogen production by ethanol steam reforming over Cu-Ni supported catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Vizcaino, A.J.; Carrero, A.; Calles, J.A. [Department of Chemical and Environmental Technology, Rey Juan Carlos University, Escuela Superior de Ciencias Experimentales y Tecnologia (ESCET), c/ Tulipan s/n, 28933 Mostoles (Spain)

    2007-07-15

    In the present work, Cu-Ni supported catalysts were tested in ethanol steam reforming reaction. Two commercial amorphous solids (SiO{sub 2} and {gamma}-Al{sub 2}O{sub 3}) and three synthesized materials (MCM-41, SBA-15 and ZSM-5 nanocrystalline) were used as support. A series of Cu-Ni/SiO{sub 2} catalysts with different Cu and Ni content were also prepared. It was found that aluminium containing supports favour ethanol dehydration to ethylene in the acid sites, which in turn, promotes the coke deactivation process. The highest hydrogen selectivity is achieved with the Cu-Ni/SBA-15 catalyst, due to a smaller metallic crystallite size. Nevertheless, the Cu-Ni/SiO{sub 2} catalyst showed the best catalytic performance, since a better equilibrium between high hydrogen selectivity and CO{sub 2}/CO{sub x} ratio is obtained. It was seen that nickel is the phase responsible for hydrogen production in a greater grade, although both CO production and coke deposition are decreased when copper is added to the catalyst. (author)

  13. LOW-TEMPERATURE GRAPHENE GROWTH ON COPPER FOIL CATALYST BY CHEMICAL VAPOUR DEPOSITION (CVD METHOD

    Directory of Open Access Journals (Sweden)

    Kasman Kasman

    2016-08-01

    Full Text Available Graphene growth at low temperatures (below 500 oC on copper catalyst by CVD method was studied. The goal of this study is to determine a minimum growth temperature for growing graphene with high quality. In this study, the catalyst used for growing graphene was copper foil (Sigma-Aldrich, code: 1001328641, 25 µm in thickness, 99.98% trace metals basis, cut into 2x1 cm2 in size  annealed at 900 oC , while the precursor used was poly(methyl methacrylate (PMMA heated at 140 oC. In graphene growth, two different growth temperatures of 350 oC and 450 oC were varied. The graphene films grown on copper foil catalyst were characterised using SEM and Raman spectroscopy. While, the films transferred onto quartz/glass/grid substrates were characterised by using SEM, Raman spectroscopy, UV-vis spectroscopy, four point probe and TEM. Results of this study showed that the 450 oC-grown samples produce a better quality graphene film compared to the 350 oC-grown samples. In other words, the minimum temperature of graphene growth is at least 450 oC for a Cu foil, since this temperature has to be sufficiently high to activate carbon diffusion and rearrangement on the catalyst surface..

  14. Amphiphilic self-assembled polymeric copper catalyst to parts per million levels: click chemistry.

    Science.gov (United States)

    Yamada, Yoichi M A; Sarkar, Shaheen M; Uozumi, Yasuhiro

    2012-06-06

    Self-assembly of copper sulfate and a poly(imidazole-acrylamide) amphiphile provided a highly active, reusable, globular, solid-phase catalyst for click chemistry. The self-assembled polymeric Cu catalyst was readily prepared from poly(N-isopropylacrylamide-co-N-vinylimidazole) and CuSO(4) via coordinative convolution. The surface of the catalyst was covered with globular particles tens of nanometers in diameter, and those sheetlike composites were layered to build an aggregated structure. Moreover, the imidazole units in the polymeric ligand coordinate to CuSO(4) to give a self-assembled, layered, polymeric copper complex. The insoluble amphiphilic polymeric imidazole Cu catalyst with even 4.5-45 mol ppm drove the Huisgen 1,3-dipolar cycloaddition of a variety of alkynes and organic azides, including the three-component cyclization of a variety of alkynes, organic halides, and sodium azide. The catalytic turnover number and frequency were up to 209000 and 6740 h(-1), respectively. The catalyst was readily reused without loss of catalytic activity to give the corresponding triazoles quantitatively.

  15. Comparison of Preparation Methods of Copper Based PGMFree Diesel-Soot Oxidation Catalysts

    Directory of Open Access Journals (Sweden)

    R. Prasad

    2011-05-01

    Full Text Available CuO-CeO2 systems have been proposed as a promising catalyst for low temperature diesel-soot oxidation. CuO-CeO2 catalysts prepared by various methods were examined for air oxidation of the soot in a semi batch tubular flow reactor. The air oxidation of soot was carried out under tight contact with soot/catalyst ratio of 1/10. Air flow rate was 150 ml/min, soot-catalyst mixture was 110 mg, heating rate was 5 0C/min. Prepared catalysts were calcined at 500 0C and their stability was examined by further heating to 800 0C for 4 hours. It was found that the selectivity of all the catalysts was nearly 100% to CO2 production. It was observed that the activity and stability of the catalysts greatly influenced by the preparation methods. The strong interaction between CuO and CeO2 is closely related to the preparation route that plays a crucial role in the soot oxidation over the CuO-CeO2 catalysts. The ranking order of the preparation methods of the catalysts in the soot oxidation performance is as follows: sol-gel > urea nitrate combustion > Urea gelation method > thermal decomposition > co-precipitation. Copyright © 2011 BCREC UNDIP. All rights reserved.(Received: 27th June 2010, Revised: 7th August 2010; Accepted: 13rd October 2010[How to Cite: R. Prasad, V.R. Bella. (2011. Comparison of Preparation Methods of Copper Based PGMFree Diesel-Soot Oxidation Catalysts. Bulletin of Chemical Reaction Engineering and Catalysis, 6(1: 15-21. doi:10.9767/bcrec.6.1.822.15-21][How to Link / DOI: http://dx.doi.org/10.9767/bcrec.6.1.822.15-21 || or local: http://ejournal.undip.ac.id/index.php/bcrec/article/view/822 | View in 

  16. Polymer-Supported Raney Nickel Catalysts for Sustainable Reduction Reactions

    Directory of Open Access Journals (Sweden)

    Haibin Jiang

    2016-06-01

    Full Text Available Green is the future of chemistry. Catalysts with high selectivity are the key to green chemistry. Polymer-supported Raney catalysts have been found to have outstanding performance in the clean preparation of some chemicals. For example, a polyamide 6-supported Raney nickel catalyst provided a 100.0% conversion of n-butyraldehyde without producing any detectable n-butyl ether, the main byproduct in industry, and eliminated the two main byproducts (isopropyl ether and methyl-iso-butylcarbinol in the hydrogenation of acetone to isopropanol. Meanwhile, a model for how the polymer support brought about the elimination of byproducts is proposed and confirmed. In this account the preparation and applications of polymer-supported Raney catalysts along with the corresponding models will be reviewed.

  17. Functionalized magnetic nanoparticles: A novel heterogeneous catalyst support

    Science.gov (United States)

    Functionalized magnetic nanoparticles have emerged as viable alternatives to conventional materials, as robust, high-surface-area heterogeneous catalyst supports. Post-synthetic surface modification protocol for magnetic nanoparticles has been developed that imparts desirable che...

  18. Interlaboratory Study on the Determination of Crude Protein in Macaroni Products on JAS by Kjeldahl Method Using Copper Catalysts

    National Research Council Canada - National Science Library

    HAKODA, Akiko; II, Yusuke; SUZUKI, Tadanao; YASUI, Akemi

    2009-01-01

    The Kjeldahl method using copper catalysts for digestion was established as an analytical method for the determination of crude protein in macaroni products in the Japanese Agricultural Standard (JAS...

  19. Quantification of zinc atoms in a surface alloy on copper in an industrial-type methanol synthesis catalyst.

    Science.gov (United States)

    Kuld, Sebastian; Conradsen, Christian; Moses, Poul Georg; Chorkendorff, Ib; Sehested, Jens

    2014-06-02

    Methanol has recently attracted renewed interest because of its potential importance as a solar fuel. Methanol is also an important bulk chemical that is most efficiently formed over the industrial Cu/ZnO/Al2O3 catalyst. The identity of the active site and, in particular, the role of ZnO as a promoter for this type of catalyst is still under intense debate. Structural changes that are strongly dependent on the pretreatment method have now been observed for an industrial-type methanol synthesis catalyst. A combination of chemisorption, reaction, and spectroscopic techniques provides a consistent picture of surface alloying between copper and zinc. This analysis enables a reinterpretation of the methods that have been used for the determination of the Cu surface area and provides an opportunity to independently quantify the specific Cu and Zn areas. This method may also be applied to other systems where metal-support interactions are important, and this work generally addresses the role of the carrier and the nature of the interactions between carrier and metal in heterogeneous catalysts. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Tungsten materials as durable catalyst supports for fuel cell electrodes

    Science.gov (United States)

    Perchthaler, M.; Ossiander, T.; Juhart, V.; Mitzel, J.; Heinzl, C.; Scheu, C.; Hacker, V.

    2013-12-01

    Durable platinum catalyst support materials, e.g. tungsten carbide (WC), tungsten oxide (WOx) and self-synthesized tungsten oxide (WOxs) were evaluated for the use in High-Temperature Proton Exchange Fuel Cells (HT-PEM) based on phosphoric acid doped polybenzimidazole as electrolyte. The support materials and the catalyst loaded support materials were characterized ex-situ by cyclic voltammetry in HClO4, potential cycling, CO-stripping, electron microscopy and X-ray diffraction measurements. The tungsten oxide and tungsten carbide based supported catalysts were compared to High Surface Area Carbon (HSAC), each coated with platinum via the same in-house manufacturing procedures. The in-house manufacturing procedures resulted in catalyst particle sizes on HSAC of 3-4 nm with a uniform distribution. The in-situ Potential Cycling experiments of WOx or WOxs supported catalysts showed much lower degradation rates compared to High Surface Area Carbons. The formation of WOx species on WC was proven by ex- and in-situ cyclic voltammetric studies and thermogravimetric analyses. X-ray diffraction, ex-situ cyclic voltammetry and in-situ cyclic voltammetry showed that WOx is formed from WC as starting material under oxidizing conditions. Finally a 1000 h durability test with WOx as catalyst support material on the anode was done in a HT-PEM fuel cell with reformed methanol on the anode.

  1. Catalysis. Highly active copper-ceria and copper-ceria-titania catalysts for methanol synthesis from CO₂.

    Science.gov (United States)

    Graciani, Jesús; Mudiyanselage, Kumudu; Xu, Fang; Baber, Ashleigh E; Evans, Jaime; Senanayake, Sanjaya D; Stacchiola, Darío J; Liu, Ping; Hrbek, Jan; Fernández Sanz, Javier; Rodriguez, José A

    2014-08-01

    The transformation of CO2 into alcohols or other hydrocarbon compounds is challenging because of the difficulties associated with the chemical activation of CO2 by heterogeneous catalysts. Pure metals and bimetallic systems used for this task usually have low catalytic activity. Here we present experimental and theoretical evidence for a completely different type of site for CO2 activation: a copper-ceria interface that is highly efficient for the synthesis of methanol. The combination of metal and oxide sites in the copper-ceria interface affords complementary chemical properties that lead to special reaction pathways for the CO2→CH3OH conversion. Copyright © 2014, American Association for the Advancement of Science.

  2. Sulfur tolerant zeolite supported platinum catalysts for aromatics hydrogenation

    Energy Technology Data Exchange (ETDEWEB)

    Bergem, Haakon

    1997-12-31

    The increased demand for transportation fuels at the expence of heavier fuel oil has forced the refinery industry to expand their conversion capacity with hydrotreating as one of the key processes. A shift towards more diesel powered vehicles along with tightening fuel regulations demanding cleaner fuels has lead to increasing interest in catalytic processes for the manufacturing of such environmentally acceptable fuels. This provides the motivation for this thesis. Its main objective was to study possible catalysts active for desulfurization, hydrogenation, and ring-opening of aromatics all in the presence of sulfur. A close examination of the physical properties and kinetical behaviour of the chosen catalysts has been performed. A high pressure reactor setup was designed and built for activity measurements. Zeolite supported platinum catalysts were prepared and both the metal and acid functions were characterized utilizing various experimental techniques. Hydrogenation of toluene was used as a model reaction and the effect of sulfur adsorption on the activity and kinetic behaviour of the catalysts was investigated. The catalyst samples showed hydrogenation activities comparable to a commercial Pt/Al2O3 catalyst. There were no clear differences in the effect of the various sulfur compounds studied. Platinum supported on zeolite Y gave considerably more sulfur tolerant catalysts compared to Al2O3 as support. 155 refs., 58 figs., 36 tabs.

  3. Hydrogenation of Tetralin over Supported Ni and Ir Catalysts

    Directory of Open Access Journals (Sweden)

    Dipali P. Upare

    2013-01-01

    Full Text Available Selective hydrogenation and ring opening (SRO of tetrahydronaphthalene (tetralin was studied over nickel and iridium supported catalysts in the context of the removal of polynuclear aromatics from diesel fuel. The tetralin hydrogenation was carried out in a fixed-bed reactor at 270°C, using H2 pressure of 30 bars, WHSV of 2.3 h−1, and H2/feed molar ratio of 40; the resultant products were analyzed by GC and GC-MS. The Ir/SiO2 catalyst gave 85% of tetralin conversion and 75.1% of decalin products selectivity whereas Ni/SiO2 catalyst showed an unprecedented high catalytic performance with 88.3% of tetralin conversion and 93% of decalin products selectivity. The catalysts were characterized by using different characterization techniques such as XRD, TPR, and HR-TEM to know the physicochemical properties as well as active sites in the catalysts.

  4. Catalytic incineration of CO and VOC emissions over supported metal oxide catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Larsson, Per-Olof

    1999-05-01

    Catalytic incineration is one of the methods to reduce the emissions of CO and VOCs. Low operation temperature and low catalyst cost are essential parameters for catalytic incinerators. Pt/Al{sub 2}O{sub 3} catalysts are frequently used today, but the cheaper metal oxide catalysts can be very competitive if comparable overall activity is obtained. This thesis concerns how it is possible to decrease the operation temperature for supported metal oxide catalysts by using different supports, active metal oxides and additives. In the thesis it is demonstrated that different copper oxide based catalysts have the best activity and durability for complete oxidation among several tested metal oxide catalysts. CuO{sub x} supported on TiO{sub 2} and Al{sub 2}O{sub 3} showed increased activity with the CuO{sub x} loading up to the threshold coverage for formation of crystalline CuO particles, which is 12 {mu}mol/m{sup 2} on TiO{sub 2} and 6 {mu}mol/m{sup 2} on Al{sub 2}O{sub 3}. Up to the threshold coverage for CuO formation, well dispersed copper oxide species were formed on TiO{sub 2}, and a dispersed copper aluminate surface phase was formed on Al{sub 2}O{sub 3}. Durability tests showed accelerated sintering of TiO{sub 2} by copper, but stabilisation was possible by modification of the TiO{sub 2} with CeO{sub x} before the deposition of CuO{sub x}. The stabilisation was obtained by formation of a Ce-O-Ti surface phase. Addition of CeO{sub x} also enhanced the activity of the copper oxide species thanks to favourable interaction between the active copper oxide species and the CeO{sub x} on the support, which could be seen as increased reducibility in TPR experiments. The increased activity and reducibility was also observed for CuO{sub x} supported on ceria modified Al{sub 2}O{sub 3}. In this regard it was shown that CuO{sub x} deposited on CeO{sub 2}(001) surfaces was substantially more active for CO oxidation than copper oxide deposited on CeO{sub 2}(111) Surfaces. This

  5. Catalytic wet peroxide oxidation of aniline in wastewater using copper modified SBA-15 as catalyst.

    Science.gov (United States)

    Kong, Liming; Zhou, Xiang; Yao, Yuan; Jian, Panming; Diao, Guowang

    2016-01-01

    SBA-15 mesoporous molecular sieves modified with copper (Cu-SBA-15) were prepared by pH-adjusting hydrothermal method and characterized by X-ray diffraction, BET, transmission electron microscopy, UV-Vis and (29)Si MAS NMR. The pH of the synthesis gel has a significant effect on the amount and the dispersion of copper on SBA-15. The Cu-SBA-15(4.5) (where 4.5 denotes the pH value of the synthesis gel) modified with highly dispersed copper was used as catalyst for the oxidation of aniline by H2O2. The Cu-SBA-15(4.5) shows a higher catalytic activity compared to CuO on the surface of SBA-15. The influences of reaction conditions, such as initial pH of the aqueous solutions, temperature, as well as the dosages of H2O2 and catalyst were investigated. Under weakly alkaline aqueous solution conditions, the aniline conversion, the H2O2 decomposition and the total organic carbon (TOC) removal could be increased significantly compared to the acid conditions. The percentage of leaching Cu(2+) could be decreased from 45.0% to 3.66% when the initial pH of solution was increased from 5 to 10. The TOC removal could be enhanced with the increases of temperature, H2O2 and catalyst dosage, but the aniline conversion and H2O2 decomposition change slightly with further increasing dosage of catalyst and H2O2. At 343 K and pH 8.0, 100% aniline conversion and 66.9% TOC removal can be achieved under the conditions of 1.0 g/L catalyst and 0.05 mol/L H2O2 after 180 min. Although copper might be slightly leached from catalyst, the homogeneous Cu(2+) contribution to the whole catalytic activity is unimportant, and the highly dispersed copper on SBA-15 plays a dominant role.

  6. Copper-Intercalated Birnessite as a Water Oxidation Catalyst.

    Science.gov (United States)

    Thenuwara, Akila C; Shumlas, Samantha L; Attanayake, Nuwan H; Cerkez, Elizabeth B; McKendry, Ian G; Frazer, Laszlo; Borguet, Eric; Kang, Qing; Zdilla, Michael J; Sun, Jianwei; Strongin, Daniel R

    2015-11-24

    We report a synthetic method to increase the catalytic activity of birnessite toward water oxidation by intercalating copper in the interlayer region of the layered manganese oxide. Intercalation of copper, verified by XRD, XPS, ICP, and Raman spectroscopy, was accomplished by exposing a suspension of birnessite to a Cu(+)-bearing precursor molecule that underwent disproportionation in solution to yield Cu(0) and Cu(2+). Electrocatalytic studies showed that the Cu-modified birnessite exhibited an overpotential for water oxidation of ∼490 mV (at 10 mA/cm(2)) and a Tafel slope of 126 mV/decade compared to ∼700 mV (at 10 mA/cm(2)) and 240 mV/decade, respectively, for birnessite without copper. Impedance spectroscopy results suggested that the charge transfer resistivity of the Cu-modified sample was significantly lower than Cu-free birnessite, suggesting that Cu in the interlayer increased the conductivity of birnessite leading to an enhancement of water oxidation kinetics. Density functional theory calculations show that the intercalation of Cu(0) into a layered MnO2 model structure led to a change of the electronic properties of the material from a semiconductor to a metallic-like structure. This conclusion from computation is in general agreement with the aforementioned impedance spectroscopy results. X-ray photoelectron spectroscopy (XPS) showed that Cu(0) coexisted with Cu(2+) in the prepared Cu-modified birnessite. Control experiments using birnessite that was decorated with only Cu(2+) showed a reduction in water oxidation kinetics, further emphasizing the importance of Cu(0) for the increased activity of birnessite. The introduction of Cu(0) into the birnessite structure also increased the stability of the electrocatalyst. At a working current of 2 mA, the Cu-modified birnessite took ∼3 times longer for the overpotential for water oxdiation to increase by 100 mV compared to when Cu was not present in the birnessite.

  7. Next Generation Catalyst Engineering via Support Modification

    Science.gov (United States)

    2016-01-21

    The second review paper focuses on the current scientific and commercial status of direct methanol fuel cell technology as a whole. This benchmark... methanol fuel cells - in the perspective of energy and sustainability”, MRS Energy and Sustainability, 2, E3 (2015) Collaborations and Technology ...Our effort focuses on identifying dopant/catalyst combinations to enhance the performance of direct methanol fuel cells. We are specifically

  8. In-situ hydrodeoxygenation of phenol by supported Ni catalyst-explanation for catalyst performance

    DEFF Research Database (Denmark)

    Wang, Ze; Zeng, Ying; Lin, Weigang

    2017-01-01

    performance improved. If gaseous hydrogen was used as the hydrogen source the activity of Ni/Al2O3 was pretty high. CO2 was found poisonous to the catalysis, due to the competitive adoption of phenol with CO2. If formic acid was replaced by methanol, the catalyst performance improved remarkably, with major...... products of cyclohexanone and cyclohexanol. The better effect of methanol enlightened the application of the supported Ni catalyst in in-situ hydrodeoxygenation of phenol....

  9. Bottom-Up Design of a Copper-Ruthenium Nanoparticulate Catalyst for Low-Temperature Ammonia Oxidation

    DEFF Research Database (Denmark)

    Chakraborty, Debasish; Damsgaard, Christian Danvad; Silva, Hugo José Lopes

    2017-01-01

    A novel nanoparticulate catalyst of copper (Cu) and ruthenium (Ru) was designed for low-temperature ammonia oxidation at near-stoichiometric mixtures using a bottom-up approach. A synergistic effect of the two metals was found. An optimum CuRu catalyst presents a reaction rate threefold higher than...

  10. Graphene-supported platinum catalysts for fuel cells

    DEFF Research Database (Denmark)

    Seselj, Nedjeljko; Engelbrekt, Christian; Zhang, Jingdong

    2015-01-01

    Increasing concerns with non-renewable energy sources drive research and development of sustainable energy technology. Fuel cells have become a central part in solving challenges associated with energy conversion. This review summarizes recent development of catalysts used for fuel cells over...... the past 15 years. It is focused on polymer electrolyte membrane fuel cells as an environmentally benign and feasible energy source. Graphene is used as a promising support material for Pt catalysts. It ensures high catalyst loading, good electrocatalysis and stability. Attention has been drawn...

  11. Catalytic wet oxidation of thiocyanate with homogeneous copper(II) sulphate catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Collado, Sergio; Laca, Adriana [Department of Chemical Engineering and Environmental Technology, University of Oviedo, c/ Julian Claveria s/n, E-33071, Oviedo (Spain); Diaz, Mario, E-mail: mariodiaz@uniovi.es [Department of Chemical Engineering and Environmental Technology, University of Oviedo, c/ Julian Claveria s/n, E-33071, Oviedo (Spain)

    2010-05-15

    The wet oxidation of thiocyanate has been investigated in a semi-batch reactor at temperatures between 423 and 473 K and pressures between 6.1 x 10{sup 3} and 1.0 x 10{sup 4} kPa in the presence of copper(II) sulphate as catalyst. The effects of copper concentration, initial thiocyanate concentration, pressure and temperature on the reaction rate were analyzed and the main products of reaction were identified. A kinetic model for the Cu-catalyzed reaction is here proposed, including temperature, oxygen concentration, and the reduction of Cu{sup 2+} to Cu{sup +} that gives an accurate prediction of the oxidation process under the assayed conditions. A mechanistic model based on the formation of a transition complex between a copper cation and two thiocyanate anions has been proposed for the catalytic wet oxidation.

  12. Catalytic wet oxidation of thiocyanate with homogeneous copper(II) sulphate catalyst.

    Science.gov (United States)

    Collado, Sergio; Laca, Adriana; Díaz, Mario

    2010-05-15

    The wet oxidation of thiocyanate has been investigated in a semi-batch reactor at temperatures between 423 and 473 K and pressures between 6.1 x 10(3) and 1.0 x 10(4)kPa in the presence of copper(II) sulphate as catalyst. The effects of copper concentration, initial thiocyanate concentration, pressure and temperature on the reaction rate were analyzed and the main products of reaction were identified. A kinetic model for the Cu-catalyzed reaction is here proposed, including temperature, oxygen concentration, and the reduction of Cu(2+) to Cu(+) that gives an accurate prediction of the oxidation process under the assayed conditions. A mechanistic model based on the formation of a transition complex between a copper cation and two thiocyanate anions has been proposed for the catalytic wet oxidation. Copyright (c) 2009 Elsevier B.V. All rights reserved.

  13. A Polyphenylene Support for Pd Catalysts with Exceptional Catalytic Activity

    DEFF Research Database (Denmark)

    Wang, Feng; Mielby, Jerrik Jørgen; Richter, Felix Herrmann

    2014-01-01

    We describe a solid polyphenylene support that serves as an excellent platform for metal-catalyzed reactions that are normally carried out under homogeneous conditions. The catalyst is synthesized by palladium-catalyzed Suzuki coupling which directly results in formation of palladium nanoparticles...... confined to a porous polyphenylene network. The composite solid is in turn highly active for further Suzuki coupling reactions, including non-activated substrates that are challenging even for molecular catalysts....

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  15. Molecular metal catalysts on supports: organometallic chemistry meets surface science.

    Science.gov (United States)

    Serna, Pedro; Gates, Bruce C

    2014-08-19

    Recent advances in the synthesis and characterization of small, essentially molecular metal complexes and metal clusters on support surfaces have brought new insights to catalysis and point the way to systematic catalyst design. We summarize recent work unraveling effects of key design variables of site-isolated catalysts: the metal, metal nuclearity, support, and other ligands on the metals, also considering catalysts with separate, complementary functions on supports. The catalysts were synthesized with the goal of structural simplicity and uniformity to facilitate incisive characterization. Thus, they are essentially molecular species bonded to porous supports chosen for their high degree of uniformity; the supports are crystalline aluminosilicates (zeolites) and MgO. The catalytic species are synthesized in reactions of organometallic precursors with the support surfaces; the precursors include M(L)2(acetylacetonate)1-2, with M = Ru, Rh, Ir, or Au and the ligands L = C2H4, CO, or CH3. Os3(CO)12 and Ir4(CO)12 are used as precursors of supported metal clusters, and some such catalysts are made by ship-in-a-bottle syntheses to trap the clusters in zeolite cages. The simplicity and uniformity of the supported catalysts facilitate precise structure determinations, even in reactive atmospheres and during catalysis. The methods of characterizing catalysts in reactive atmospheres include infrared (IR), extended X-ray absorption fine structure (EXAFS), X-ray absorption near edge structure (XANES), and nuclear magnetic resonance (NMR) spectroscopies, and complementary methods include density functional theory and atomic-resolution aberration-corrected scanning transmission electron microscopy for imaging of individual metal atoms. IR, NMR, XANES, and microscopy data demonstrate the high degrees of uniformity of well-prepared supported species. The characterizations determine the compositions of surface metal complexes and clusters, including the ligands and the metal-support

  16. Preparation and Characterization of Sugar Based Catalyst on Various Supports

    Directory of Open Access Journals (Sweden)

    Jidon Adrian Janaun

    2017-04-01

    Full Text Available A novel structured carbon-based acid catalyst was prepared by depositing the carbon precursor onto glass, ceramic and aluminum supports via dip-coating method, followed by carbonization process for converting the d-glucose layer into black carbon char in an inert nitrogen environment at 400 °C. Then, the –SO3H group was introduced into the framework of the carbon char by multiple vapor phase sulfonation. Four different carbonization methods were carried out (dry pyrolysis and hydrothermal carbonization with or without pressurized in the catalyst preparation while among the carbonization methods, the samples which prepared from dry pyrolysis without pressurized process showed the strong acidity due to highest adsorption of acid group in the catalyst surface although the catalyst attached onto the support was the least compared to other preparation methods. Among the catalysts, the sulfonated carbon-base catalyst that is attached on the ceramic support exhibited the highest aci-dity (1.327 mmol/g followed by the catalyst deposited on the glass (0.917 mmol/g and aluminum (0.321 mmol/g supports. The porous structure of ceramic surface, allowed a better interaction between reactants and –SO3H site in the carbon. Through the FT-IR analysis, it was observed that the functional groups –COOH, –OH, and –SO3H were present in the active sites of the catalysts. The surface areas of  glass (Si–SC, ceramic (Ce–SC and aluminum (Al–SC catalysts were larger than 1 m2/g, whereas the pore size belongs to macroporous as the average pore size is more than 50 nm. It is also stable within the temperature of 400 °C as there was less than 10% weight loss revealed from the TGA analysis. Copyright © 2017 BCREC GROUP. All rights reserved Received: 20th April 2016; Revised: 14th October 2016; Accepted: 17th October 2016 How to Cite: Janaun, J.A., Mey, T.J., Bono, A., Krishnaiah, D. (2017. Preparation and Characterization of Sugar Based Catalyst on Various

  17. Synthesis-Structure-Performance Relationships for Supported Metal Catalysts

    NARCIS (Netherlands)

    Munnik, Peter|info:eu-repo/dai/nl/328228524

    2014-01-01

    Heterogeneous catalysts, which consist of many metal nanoparticles supported on highly porous, mechanically strong and chemically inert supports, are at the center of many existing as well as new and more sustainable processes, such as energy conversion and storage, nanoelectronics and the catalytic

  18. Fly ash zeolite catalyst support for Fischer-Tropsch synthesis

    Science.gov (United States)

    Campen, Adam

    This dissertation research aimed at evaluating a fly ash zeolite (FAZ) catalyst support for use in heterogeneous catalytic processes. Gas phase Fischer-Tropsch Synthesis (FTS) over a fixed-bed of the prepared catalyst/FAZ support was identified as an appropriate process for evaluation, by comparison with commercial catalyst supports (silica, alumina, and 13X). Fly ash, obtained from the Wabash River Generating Station, was first characterized using XRD, SEM/EDS, particle size, and nitrogen sorption techniques. Then, a parametric study of a two-step alkali fusion/hydrothermal treatment process for converting fly ash to zeolite frameworks was performed by varying the alkali fusion agent, agent:flyash ratio, fusion temperature, fused ash/water solution, aging time, and crystallization time. The optimal conditions for each were determined to be NaOH, 1.4 g NaOH: 1 g fly ash, 550 °C, 200 g/L, 12 hours, and 48 hours. This robust process was applied to the fly ash to obtain a faujasitic zeolite structure with increased crystallinity (40 %) and surface area (434 m2/g). Following the modification of fly ash to FAZ, ion exchange of H+ for Na+ and cobalt incipient wetness impregnation were used to prepare a FTS catalyst. FTS was performed on the catalysts at 250--300 °C, 300 psi, and with a syngas ratio H2:CO = 2. The HFAZ catalyst support loaded with 11 wt% cobalt resulted in a 75 % carbon selectivity for C5 -- C18 hydrocarbons, while methane and carbon dioxide were limited to 13 and 1 %, respectively. Catalyst characterization was performed by XRD, N2 sorption, TPR, and oxygen pulse titration to provide insight to the behavior of each catalyst. Overall, the HFAZ compared well with silica and 13X supports, and far exceeded the performance of the alumina support under the tested conditions. The successful completion of this research could add value to an underutilized waste product of coal combustion, in the form of catalyst supports in heterogeneous catalytic processes.

  19. Carbon xerogels as catalyst supports for PEM fuel cell cathode

    Energy Technology Data Exchange (ETDEWEB)

    Job, Nathalie; Lambert, Stephanie [Laboratoire de Genie chimique, Universite de Liege, Institut de Chimie B6a, Sart-Tilman, B-4000 Liege (Belgium); Marie, Julien; Berthon-Fabry, Sandrine; Achard, Patrick [Ecole des Mines de Paris, Centre Energetique et Procedes, BP 207, F-06904 Sophia-Antipolis Cedex (France)

    2008-09-15

    Carbon xerogels with various pore textures were prepared by evaporative drying and pyrolysis of resorcinol-formaldehyde gels, and used as supports for Pt catalysts in PEM fuel cell cathodes. The goal of this study was to determine whether carbon xerogels could replace the carbon aerogels which were previously used as Pt catalyst supports in the same electrochemical system, and to determine how the pore texture influences the cell performances. Pt catalysts were prepared by impregnation of carbon supports with aqueous H{sub 2}PtCl{sub 6} solution followed by reduction in aqueous phase with NaBH{sub 4}. Fuel cell measurements show that the metal surface actually available for the oxygen reduction reaction and the voltage losses due to diffusion phenomena strongly depend on the carbon pore texture. Finally, some carbon xerogels yield similar performance than carbon aerogels. (author)

  20. Templating Routes to Supported Oxide Catalysts by Design

    Energy Technology Data Exchange (ETDEWEB)

    Notestein, Justin M. [Northwestern Univ., Evanston, IL (United States)

    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

  1. Nitrogen-doped carbon nanotubes as a metal catalyst support

    CSIR Research Space (South Africa)

    Mabena, LF

    2011-05-01

    Full Text Available al. (2008) Pt 1.5?8.4 30 PEM fuel cells Chen et al. (2009) Ru 0.1?1.9 0.8 Ammonia decomposition Chen et al. (2010a, b, c) Ru 4 2 Ammonia decomposition Garc??a-Garc??a et al. (2010) Pt?Ru Unknown 40 Methanol oxidation Jiang et al. (2010) Pt?Ru 4 9... dispersion of nanoparticles (Gao et al. 2006).The support can also influence the performance of the catalyst through electronic interactions and migration effects (Mhlanga 2009). A catalyst support is a material on which an active metal nanoparticle...

  2. A study of platinum-supported catalysts through hyperfine interactions

    Science.gov (United States)

    Saitovitch, H.; Silva, P. R. J.; Rodriguez, A. M.; Weberszpil, J.; Passos, F. B.; Schmal, M.

    1994-12-01

    The effect of indium addition on alumina-supported platinum catalysts was investigated by measurements of hyperfine interactions. Via lime differential perturbed angular correlation spectroscopy (TDPAC) on111Cd, Pt/Al2O3 catalysts were studied in the flow of a heptane/H2 gas stream. The results indicate that some amount of indium sticks to platinum which is then dispersed on the support surface. The amount of In that is free from platinum is mobile under reaction conditions, being capable of diluting platinum particles and draining off coke precursors from the platinum surface.

  3. A study of platinum-supported catalysts through hyperfine interactions

    Energy Technology Data Exchange (ETDEWEB)

    Saitovitch, H. (Centro Brasileiro de Pesquisas Fisicas (CBPF/CNPq), Rio de Janeiro, RJ (Brazil)); Silva, P.R.J. (Centro Brasileiro de Pesquisas Fisicas (CBPF/CNPq), Rio de Janeiro, RJ (Brazil)); Rodriguez, A.M. (Centro Brasileiro de Pesquisas Fisicas (CBPF/CNPq), Rio de Janeiro, RJ (Brazil)); Weberszpil, J. (Centro Brasileiro de Pesquisas Fisicas (CBPF/CNPq), Rio de Janeiro, RJ (Brazil)); Passos, F.B. (Dept. Eng. Quimica, Univ. Fed. Fluminense, Niteroi, RJ (Brazil)); Schmal, M. (COPPE/EQ, Univ. Fed. Rio de Janeiro, RJ (Brazil))

    1994-05-01

    The effect of indium addition on alumina-supported platinum catalysts was investigated by measurements of hyperfine interactions. Via time differential perturbed angular correlation spectroscopy (TDPAC) on [sup 111]Cd, Pt/Al[sub 2]O[sub 3] catalysts were studied in the flow of a heptane/H[sub 2] gas stream. The results indicate that some amount of indium sticks to platinum which is then dispersed on the support surface. The amount of In that is free from platinum is mobile under reaction conditions, being capable of diluting platinum particles and draining off coke precursors from the platinum surface. (orig.)

  4. Dissolution of Metal Supported Spent Auto Catalysts in Acids

    Directory of Open Access Journals (Sweden)

    Fornalczyk A.

    2016-03-01

    Full Text Available Metal supported auto catalysts, have been used in sports and racing cars initially, but nowadays their application systematically increases. In Metal Substrate (supported Converters (MSC, catalytic functions are performed by the Platinum Group Metals (PGM: Pt, Pd, Rh, similarly to the catalysts on ceramic carriers. The contents of these metals make that spent catalytic converters are valuable source of precious metals. All over the world there are many methods for the metals recovery from the ceramic carriers, however, the issue of platinum recovery from metal supported catalysts has not been studied sufficiently yet. The paper presents preliminary results of dissolution of spent automotive catalyst on a metal carrier by means of acids: H2SO4, HCl, HNO3, H3PO4. The main assumption of the research was the dissolution of base metals (Fe, Cr, Al from metallic carrier of catalyst, avoiding dissolution of PGMs. Dissolution was the most effective when concentrated hydrochloric acid, and 2M sulfuric acid (VI was used. It was observed that the dust, remaining after leaching, contained platinum in the level of 0.8% and 0.7%, respectively.

  5. Graphitised carbon nanofibres as catalyst support for PEMFC

    Energy Technology Data Exchange (ETDEWEB)

    Yli-Rantala, E.; Pasanen, A.; Kauranen, P. [VTT Technical Research Centre of Finland, P. O. Box 1300, FI-33101 Tampere (Finland); Ruiz, V.; Borghei, M.; Kauppinen, E. [Department of Applied Physics, Aalto University, P. O. Box 15100, FI-00076 Aalto (Finland); Oyarce, A.; Lindbergh, G.; Lagergren, C. [Royal Institute of Technology, Teknikringen 42, SE-10044 Stockholm (Sweden); Darab, M.; Sunde, S. [Norwegian University of Science and Technology, Sem Saelands vei 12, NO-7495 Trondheim (Norway); Thomassen, M. [SINTEF, Strindveien 4, NO-7465 Trondheim (Norway); Ma-Andersen, S.; Skou., E. [University of Southern Denmark, Campusvej 55, DK-5230 Odense (Denmark)

    2011-12-15

    Graphitised carbon nanofibres (G-CNFs) show superior thermal stability and corrosion resistance in PEM fuel cell environment over traditional carbon black (CB) and carbon nanotube catalyst supports. However, G-CNFs have an inert surface with only very limited amount of surface defects for the anchorage of Pt catalyst nanoparticles. Modification of the fibre surface is therefore needed. In this study Pt nanoparticles have been deposited onto as-received and surface-modified G-CNFs. The surface modifications of the fibres comprise acid treatment and nitrogen doping by pyrolysis of a polyaniline (PANI) precursor. The modified surfaces were studied by FTIR and XPS and the electrochemical characterization, including long-term Pt stability tests, was performed using a low-temperature PEMFC single cell. The performance and stability of the G-CNF supported catalysts were compared with a CB supported catalyst and the effects of the different surface treatments were discussed. On the basis of these results, new membrane electrode assemblies (MEAs) were manufactured and tested also for carbon corrosion by in situ FTIR analysis of the cathode exhaust gases. It was observed that the G-CNFs showed 5 times lower carbon corrosion compared to CB based catalyst when potential reached 1.5 V versus RHE in simulated start/stop cycling. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. Reactions of synthesis gas on silica supported transition metal catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Niemelae, M. [VTT Chemical Technology, Espoo (Finland). Lab. of Industrial Chemistry

    1997-12-31

    The effect of catalyst precursor and composition on the activation of CO was investigated using CO hydrogenation as a test reaction. The interrelations of preparation, pretreatment, characteristics and activity were clarified. For Co/SiO{sub 2} catalyst, MgO promotion increased the CO adsorption capacity and the hydrogen uptake, although the extent of reduction for cobalt remained the same or decreased. The conversion per active metallic cobalt site consequently increased in conjunction with MgO promotion, while the effect on overall performance per 1 g of catalyst remained moderate. The precursor affected the performance of Co/SiO{sub 2} considerably. CO was more strongly adsorbed on catalysts of carbonyl origin than on those derived from cobalt nitrate, the activity thus being higher. Although the nitrate derived Co/SiO{sub 2} appeared both to retain its activity and to regain its adsorption capacity better than the catalysts of carbonyl origin, the performance of the latter was superior with time on stream. For tetranuclear cluster based Co-Ru and Co-Rh catalysts, rhodium or ruthenium was in contact with the support and cobalt was enriched on top. On Co-Ru/SiO{sub 2} ruthenium enhanced deactivation, and no benefits in activity or oxygenate selectivity were achieved relative to the monometallic catalysts of cluster origin. The Co-Rh/SiO{sub 2} catalysts were also less active than those derived from monometallic clusters, but they exhibited higher selectivities to oxygenated compounds due to the presence of active sites on the perimeter of the cobalt particles located on rhodium. The highest selectivity to oxygenates was achieved by changing the decomposition atmosphere of Rh{sub 4}(CO){sub 12}/SiO{sub 2} from hydrogen to carbon monoxide. The results also showed two types of active sites to be operative in the formation of oxygenates - one for ethanol and another for aldehydes. (orig.) 69 refs.

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

    Science.gov (United States)

    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. Chemical Conversions of Biomass-Derived Platform Chemicals over Copper-Silica Nanocomposite Catalysts.

    Science.gov (United States)

    Upare, Pravin P; Hwang, Young Kyu; Lee, Jong-Min; Hwang, Dong Won; Chang, Jong-San

    2015-07-20

    Biomass and biomass-derived carbohydrates have a high extent of functionality, unlike petroleum, which has limited functionality. In biorefinery applications, the development of methods to control the extent of functionality in final products intended for use as fuels and chemicals is a challenge. In the chemical industry, heterogeneous catalysis is an important tool for the defunctionalization of functionalized feedstocks and biomass-derived platform chemicals to produce value-added chemicals. Herein, we review the recent progress in this field, mainly of vapor phase chemical conversion of biomass-derived C4 -C6 carboxylic acids and esters using copper-silica nanocomposite catalysts. We also demonstrate that these nanocomposite catalysts very efficiently convert biomass-derived platform chemicals into cyclic compounds, such as lactones and hydrofurans, with high selectivities and yields. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Efficient Copper-bisisoquinoline-based Catalysts for Selective Aerobic Oxidation of Alcohols to Aldehydes and Ketones

    Directory of Open Access Journals (Sweden)

    Zaher M. A. Judeh

    2007-06-01

    Full Text Available The selective oxidation of alcohols with molecular oxygen was efficientlycompleted in high conversion and selectivity using copper-bisisoquinoline-based catalystsunder mild reaction condition. The effects of various parameters such as reactiontemperature, reaction time, oxidant, ligands, etc, were studied. Solvent effect has been aswell studied in ionic liquids [bmim]PF6, [omim]BF4 and [hmim]BF4, comparing totraditional volatile organic solvent. The use of ionic liquids was found to enhance thecatalytic properties of the catalysts used.

  10. Amination of ethers using chloramine-T hydrate and a copper(I) catalyst.

    Science.gov (United States)

    Albone, David P; Challenger, Stephen; Derrick, Andrew M; Fillery, Shaun M; Irwin, Jacob L; Parsons, Christopher M; Takada, Hiroya; Taylor, Paul C; Wilson, D James

    2005-01-07

    Amination of C-H bonds activated by ether oxygen atoms is facile with chloramine-T as nitrene source and copper(I) chloride in acetonitrile as catalyst. For cyclic ethers the hemiaminal products are generally stable and can be isolated pure. For acyclic ethers, the hemiaminal products, as expected, fragment with elimination of alcohol to yield imines. When activation of benzylic positions is remote through a conjugated system, stable benzylamine derivatives are isolated. Mechanistic studies are consistent with concerted insertion of an electrophilic nitrenoid into the C-H bond in the rate-determining step, though in an asynchronous manner with a more activated substrate.

  11. Ordered mesoporous materials as model supports to study catalyst preparation

    NARCIS (Netherlands)

    Sietsma, J.R.A.

    2007-01-01

    Catalysts are indispensable to modern-day society because of their prominent role in petroleum refining, chemical processing, and the reduction of environmental pollution. The catalytically active component often consists of small metal (oxide) particles that are supported on a carrier such as

  12. Carbon Nanofibers as Catalyst Support for Noble Metals

    NARCIS (Netherlands)

    Toebes, M.L.

    2004-01-01

    In the quest for new and well-defined support materials for heterogeneous catalysts we explored the potential of carbon nanofibers (CNF). CNF belongs to the by now extensive family of synthetic graphite-like carbon materials with advantageous and tunable physico-chemical properties. Aim of the work

  13. STRONTIUM AS AN EFFICIENT PROMOTER FOR SUPPORTED PALLADIUM HYDROGENATION CATALYSTS

    Science.gov (United States)

    The effect of strontium promotion is studied for a series of supported palladium catalysts such as Pd/zeolite-β, Pd/Al2O3, Pd/SiO2, Pd/hydrotalcite and Pd/MgO. Strontium is found to be an effective promoter for enhancing the metal area, perce...

  14. Graphitised Carbon Nanofibres as Catalyst Support for PEMFC

    DEFF Research Database (Denmark)

    Yli-Rantala, E.; Pasanen, A.; Kauranen, P.

    2011-01-01

    Graphitised carbon nanofibres (G-CNFs) show superior thermal stability and corrosion resistance in PEM fuel cell environment over traditional carbon black (CB) and carbon nanotube catalyst supports. However, G-CNFs have an inert surface with only very limited amount of surface defects for the anc......Graphitised carbon nanofibres (G-CNFs) show superior thermal stability and corrosion resistance in PEM fuel cell environment over traditional carbon black (CB) and carbon nanotube catalyst supports. However, G-CNFs have an inert surface with only very limited amount of surface defects...... for the anchorage of Pt catalyst nanoparticles. Modification of the fibre surface is therefore needed. In this study Pt nanoparticles have been deposited onto as-received and surface-modified G-CNFs. The surface modifications of the fibres comprise acid treatment and nitrogen doping by pyrolysis of a polyaniline...... (PANI) precursor. The modified surfaces were studied by FTIR and XPS and the electrochemical characterization, including long-term Pt stability tests, was performed using a low-temperature PEMFC single cell. The performance and stability of the G-CNF supported catalysts were compared with a CB supported...

  15. Highly Loaded Carbon Black Supported Platinum Catalysts for Fuel Batteries

    OpenAIRE

    Kaluža, Luděk

    2014-01-01

    Carbon supported Pt represents conventional catalyst in polymer electrolyte membrane fuel battery (PEM fuel cell). The aim of this work was to elucidate on the methods of Pt deposition on carbon black to achieve high loadings of Pt of about 60 wt.% in highly dispersed form.

  16. Hydrochlorination of acetylene using supported bimetallic Au-based catalysts

    OpenAIRE

    Conte, Marco; Carley, Albert Frederick; Attard, Gary Anthony; Herzing, Andrew A.; Kiely, Christopher John; Hutchings, Graham John

    2008-01-01

    A detailed study of the hydrochlorination of acetylene and higher alkynes using a supported gold catalyst is described and discussed. A series of reactions using sequential exposure of the catalysts to C2H2 and HCl demonstrate that exposure to HCl prior to reaction of C2H2/HCl leads to enhanced activity whereas exposure to C2H2 leads to deactivation. The reaction of higher alkynes is affected by steric factors with the trend in activity being: acetylene (ca. 40 % conversion)>> hex-1-yne (10%)...

  17. Polyvinylpolypyrrolidone Supported Brønsted Acidic Catalyst for Esterification

    Directory of Open Access Journals (Sweden)

    Song Wang

    2016-01-01

    Full Text Available A polyvinylpolypyrrolidone (PVPP supported Brønsted acidic catalyst ([PVPP-BS]HSO4 was prepared by coupling SO3H-functionalized polyvinylpolypyrrolidone with H2SO4 in this work. After the characterization through FT-IR, FESEM, TG, BET, and elemental analysis, it was found that 1,4-butane sultone (BS and sulfuric acid reacted with PVPP and were immobilized on PVPP surface. The prepared [PVPP-BS]HSO4 catalyst shows high catalytic activity for a series of esterification reactions and could be separated from the reacted mixture easily. Moreover, this catalyst could be recycled and reused for six times without significant loss of catalytic performance.

  18. Determination of the surface area and sizes of supported copper nanoparticles through organothiol adsorption—ñhemisorption

    Energy Technology Data Exchange (ETDEWEB)

    Ndolomingo, Matumuene Joe; Meijboom, Reinout, E-mail: rmeijboom@uj.ac.za

    2016-12-30

    Highlights: • Cu on γ-Al{sub 2}O{sub 3} catalysts were prepared and characterized. • The ligand sorption-based technique was used for the determination of specific surface area and particle sizes. • The ligand packing density on Cu nanoparticles was quantified. • A fair agreement was found between the Cu particle sizes obtained from ligand adsorption and TEM methods. • The oxidation of morin by hydrogen peroxide was used to evaluate the catalytic activities of the Cu supported catalysts. - Abstract: The mechanisms involving the nanoparticle surfaces in catalytic reactions are more difficult to elucidate due to the nanoparticle surface unevenness, size distributions, and morphological irregularity. True surface area and particle sizes determination are key aspects of the activity of metal nanoparticle catalysts. Here we report on the organothiol adsorption-based technique for the determination of specific surface area of Cu nanoparticles, and their resultant sizes on γ-Al{sub 2}O{sub 3} supports. Quantification of ligand packing density on copper nanoparticles is also reported. The concentration of the probe ligand, 2-mercaptobenzimidazole (2-MBI) before and after immersion of supported copper catalysts was determined by ultraviolet-visible spectrometry (UV–vis). The amount of ligand adsorbed was found to be proportional to the copper nanoparticles surface area. Atomic absorption spectrometry (AAS), N{sub 2}-physisorption (BET), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA) were used for the characterization of the catalysts. A fair agreement was found between particle sizes obtained from ligand adsorption and TEM methods. The catalytic activity of the copper nanoparticles related to their inherent surface area was evaluated using the model reaction of the oxidation of morin by hydrogen peroxide.

  19. Metal Phosphate-Supported Pt Catalysts for CO Oxidation

    Directory of Open Access Journals (Sweden)

    Xiaoshuang Qian

    2014-12-01

    Full Text Available Oxides (such as SiO2, TiO2, ZrO2, Al2O3, Fe2O3, CeO2 have often been used to prepare supported Pt catalysts for CO oxidation and other reactions, whereas metal phosphate-supported Pt catalysts for CO oxidation were rarely reported. Metal phosphates are a family of metal salts with high thermal stability and acid-base properties. Hydroxyapatite (Ca10(PO46(OH2, denoted as Ca-P-O here also has rich hydroxyls. Here we report a series of metal phosphate-supported Pt (Pt/M-P-O, M = Mg, Al, Ca, Fe, Co, Zn, La catalysts for CO oxidation. Pt/Ca-P-O shows the highest activity. Relevant characterization was conducted using N2 adsorption-desorption, inductively coupled plasma (ICP atomic emission spectroscopy, X-ray diffraction (XRD, transmission electron microscopy (TEM, CO2 temperature-programmed desorption (CO2-TPD, X-ray photoelectron spectroscopy (XPS, and H2 temperature-programmed reduction (H2-TPR. This work furnishes a new catalyst system for CO oxidation and other possible reactions.

  20. Study on the synthesis of novel TiO2-copper porphyrin catalyst and photocatalytic degradation of methyl orange

    Directory of Open Access Journals (Sweden)

    Shaorui CHEN

    2017-10-01

    Full Text Available In order to study the effect of different length side chain catalysts on photocatalytic degradation of methyl orange solution, solving the poroblem of water pollution control, four novel porphyrins and their corresponding copper complexes are synthesized from the starting material 1-naphthol, and their structures are characterized by MS, NMR and elemental analysis. Novel TiO2-porphyrins hybrid systems are prepared and its photocatalytic activity is investigated by photodegradation of methyl orange in aqueous solution under visible light. The results indicate that when there are side chains on the benzene ring of copper-porphyrin derivatives, the photocatalytic activity of substituted TiO2-copper porphyrins is better than TiO2-copper tetraphenyl porphyrin, but the effect of the side chains' length on the activity is not obvious. This study provides an idea for the synthesis of highly efficient catalysts in the future.

  1. Co-Assembled Supported Catalysts: Synthesis of Nano-Structured Supported Catalysts with Hierarchic Pores through Combined Flow and Radiation Induced Co-Assembled Nano-Reactors

    Directory of Open Access Journals (Sweden)

    Galip Akay

    2016-05-01

    Full Text Available A novel generic method of silica supported catalyst system generation from a fluid state is presented. The technique is based on the combined flow and radiation (such as microwave, thermal or UV induced co-assembly of the support and catalyst precursors forming nano-reactors, followed by catalyst precursor decomposition. The transformation from the precursor to supported catalyst oxide state can be controlled from a few seconds to several minutes. The resulting nano-structured micro-porous silica supported catalyst system has a surface area approaching 300 m2/g and X-ray Diffraction (XRD-based catalyst size controlled in the range of 1–10 nm in which the catalyst structure appears as lamellar sheets sandwiched between the catalyst support. These catalyst characteristics are dependent primarily on the processing history as well as the catalyst (Fe, Co and Ni studied when the catalyst/support molar ratio is typically 0.1–2. In addition, Ca, Mn and Cu were used as co-catalysts with Fe and Co in the evaluation of the mechanism of catalyst generation. Based on extensive XRD, Scanning Electron Microscopy (SEM and Transmission Electron Microscopy (TEM studies, the micro- and nano-structure of the catalyst system were evaluated. It was found that the catalyst and silica support form extensive 0.6–2 nm thick lamellar sheets of 10–100 nm planar dimensions. In these lamellae, the alternate silica support and catalyst layer appear in the form of a bar-code structure. When these lamellae structures pack, they form the walls of a micro-porous catalyst system which typically has a density of 0.2 g/cm3. A tentative mechanism of catalyst nano-structure formation is provided based on the rheology and fluid mechanics of the catalyst/support precursor fluid as well as co-assembly nano-reactor formation during processing. In order to achieve these structures and characteristics, catalyst support must be in the form of silane coated silica nano

  2. Silver-Copper Nanoalloy Catalyst Layer for Bifunctional Air Electrodes in Alkaline Media.

    Science.gov (United States)

    Wu, Xiaoqiang; Chen, Fuyi; Jin, Yachao; Zhang, Nan; Johnston, Roy L

    2015-08-19

    A carbon-free and binder-free catalyst layer composed of a Ag-Cu nanoalloy on Ni foam was used as the air cathode in a zinc-air battery for the first time. The Ag-Cu catalyst was prepared using pulsed laser deposition. The structures of the catalysts were found to consist of crystalline Ag-Cu nanoalloy particles with an average size of 2.58 nm embedded in amorphous Cu films. As observed in the X-ray photoelectron spectra, the Ag 3d core levels shifted to higher binding energies, whereas the Cu 2p core levels shifted to lower binding energies, indicating alloying of the silver and copper. Rotating disk electrode measurements indicated that the oxygen reduction reaction (ORR) proceeded through a four-electron pathway on the Ag50Cu50 and Ag90Cu10 nanoalloy catalysts in alkaline solution. Moreover, the catalytic activity of Ag50Cu50 in the ORR is more efficient than that of Ag90Cu10. By performing charge and discharge cycling measurements, the Ag50Cu50 catalyst layer was confirmed to have a maximum power density of approximately 86.3 mW cm(-2) and an acceptable cell voltage at 0.863 V for current densities up to 100 mA cm(-2) in primary zinc-air batteries. In addition, a round-trip efficiency of approximately 50% at a current density of 20 mA cm(-2) was also obtained in the test.

  3. Nanoscale tomography reveals the deactivation of automotive copper-exchanged zeolite catalysts.

    Science.gov (United States)

    Schmidt, Joel E; Oord, Ramon; Guo, Wei; Poplawsky, Jonathan D; Weckhuysen, Bert M

    2017-11-21

    Copper-exchanged zeolite chabazite (Cu-SSZ-13) was recently commercialized for the selective catalytic reduction of NO X with ammonia in vehicle emissions as it exhibits superior reaction performance and stability compared to all other catalysts, notably Cu-ZSM-5. Herein, the 3D distributions of Cu as well as framework elements (Al, O, Si) in both fresh and aged Cu-SSZ-13 and Cu-ZSM-5 are determined with nanometer resolution using atom probe tomography (APT), and correlated with catalytic activity and other characterizations. Both fresh catalysts contain a heterogeneous Cu distribution, which is only identified due to the single atom sensitivity of APT. After the industry standard 135,000 mile simulation, Cu-SSZ-13 shows Cu and Al clustering, whereas Cu-ZSM-5 is characterized by severe Cu and Al aggregation into a copper aluminate phase (CuAl 2 O 4 spinel). The application of APT as a sensitive and local characterization method provides identification of nanometer scale heterogeneities that lead to catalytic activity and material deactivation.

  4. Microstructural stability of supported metal catalysts: A phase field approach

    Science.gov (United States)

    Davis, Ryan; Haataja, Mikko

    2017-11-01

    The long-term stability of supported metal catalysts designed for solid-oxide fuel cell (SOFC) anodes is evaluated using a phase field simulation approach. Porous support structures are numerically sintered and then infiltrated with a nanoscale catalyst phase to mimic scaffolds fabricated via both pyrolysis and acid leaching techniques. Simulations capture the dewetting, particle agglomeration, and coarsening processes that occur during extended operation at elevated temperatures. We systematically explore the microstructural evolution of the active phase for a range of infiltration loadings from 2 to 21% and report on common performance metrics, such as triple phase boundary (TPB) density and contiguity. Ostwald ripening and particle migration and coalescence events are identified as dominant mechanisms contributing to severe reductions in the TPB density and catalyst deactivation. Despite marked differences between the simulated pyrolyzed and leached scaffold structures, the resulting TPB densities are comparable in value. Additionally, we show that tuning the metal catalyst/scaffold contact angle between 60∘ and 120∘ does not significantly affect TPB density. More broadly, this work elucidates the challenges associated with stabilizing nanoscale dispersions prepared by infiltration and similar techniques.

  5. Synergetic effect of copper-plating wastewater as a catalyst for the destruction of acrylonitrile wastewater in supercritical water oxidation.

    Science.gov (United States)

    Shin, Young Ho; Lee, Hong-shik; Lee, Young-Ho; Kim, Jaehoon; Kim, Jae-Duck; Lee, Youn-Woo

    2009-08-15

    A new supercritical water oxidation process for the simultaneous treatment of mixed wastewater containing wastewater from acrylonitrile manufacturing processes and copper-plating processes was investigated using a continuous tubular reactor system. Experiments were carried out at temperatures ranging from 400 to 600 degrees C and a pressure of 25 MPa. The residence time was fixed at 2s by changing the flow rates of feeds, depending on reaction temperature. The initial total organic carbon (TOC) concentration of the wastewaters and the O(2) concentration at the reactor inlet were kept constant at 0.49 and 0.74 mol/L. It was confirmed that the copper-plating wastewater accelerated the TOC conversion of acrylonitrile wastewater from 17.6% to 67.3% at a temperature of 450 degrees C. Moreover, copper and copper oxide nanoparticles were generated in the process of supercritical water oxidation (SCWO) of mixed wastewater. 99.8% of copper in mixed wastewater was recovered as solid copper and copper oxides at a temperature of 600 degrees C, with their average sizes ranging from 150 to 160 nm. Our study showed that SCWO provides a synergetic effect for simultaneous treatment of acrylonitrile and copper-plating wastewater. During the reaction, the oxidation rate of acrylonitrile wastewater was enhanced due to the in situ formation of nano-catalysts of copper and/or copper oxides, while the exothermic decomposition of acrylonitrile wastewater supplied enough heat for the recovery of solid copper and copper oxides from copper-plating wastewater. The synergetic effect of wastewater treatment by the newly proposed SCWO process leads to full TOC conversion, color removal, detoxification, and odor elimination, as well as full recovery of copper.

  6. Effect of Oxide Coating on Performance of Copper-Zinc Oxide-Based Catalyst for Methanol Synthesis via Hydrogenation of Carbon Dioxide

    Directory of Open Access Journals (Sweden)

    Tetsuo Umegaki

    2015-11-01

    Full Text Available The effect of oxide coating on the activity of a copper-zinc oxide–based catalyst for methanol synthesis via the hydrogenation of carbon dioxide was investigated. A commercial catalyst was coated with various oxides by a sol-gel method. The influence of the types of promoters used in the sol-gel reaction was investigated. Temperature-programmed reduction-thermogravimetric analysis revealed that the reduction peak assigned to the copper species in the oxide-coated catalysts prepared using ammonia shifts to lower temperatures than that of the pristine catalyst; in contrast, the reduction peak shifts to higher temperatures for the catalysts prepared using L(+-arginine. These observations indicated that the copper species were weakly bonded with the oxide and were easily reduced by using ammonia. The catalysts prepared using ammonia show higher CO2 conversion than the catalysts prepared using L(+-arginine. Among the catalysts prepared using ammonia, the silica-coated catalyst displayed a high activity at high temperatures, while the zirconia-coated catalyst and titania-coated catalyst had high activity at low temperatures. At high temperature the conversion over the silica-coated catalyst does not significantly change with reaction temperature, while the conversion over the zirconia-coated catalyst and titania-coated catalyst decreases with reaction time. From the results of FTIR, the durability depends on hydrophilicity of the oxides.

  7. Texture of Mo-containing hydrodesulfurization catalysts on different supports

    Energy Technology Data Exchange (ETDEWEB)

    Krasnopol' skaya, S.M.; Lur' e, M.A.; Kurets, I.Z.; Rak, V.S.; Belyaeva, V.A.; Shmidt, F.K.

    1988-10-01

    The thermal desorption of nitrogen was used to investigate the texture of molybdenum-containing hydrodesulfurization catalysts, synthesized on the basis of ..gamma..-Al/sub 2/O/sub 3/ and a genetic mixture of mountain cork (palygorskite) and montmorillonite. Their activity in the hydrogenolysis of thiophene has been determined. It has been shown that in the preparation of the oxide or sulfide forms the texture of the contact, containing the natural support, changes more strongly than that based on aluminum oxide. Elimination of the oxidizing calcination stage produces sulfide forms of the catalysts with a larger specific surface, porosity, and higher catalytic activity. A stronger effect is obtained on the natural support.

  8. Natural polymers supported copper nanoparticles for pollutants degradation

    Energy Technology Data Exchange (ETDEWEB)

    Haider, Sajjad [Department of Chemical Engineering, College of Engineering, King Saud University, P.O. Box 800, Riyadh 11421 (Saudi Arabia); Kamal, Tahseen, E-mail: tkkhan@kau.edu.sa [Department of Chemistry, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21589 (Saudi Arabia); Center of Excellence for Advanced Materials Research (CEAMR), King Abdulaziz University, P.O. Box 80203, Jeddah 21589 (Saudi Arabia); Khan, Sher Bahadar [Department of Chemistry, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21589 (Saudi Arabia); Center of Excellence for Advanced Materials Research (CEAMR), King Abdulaziz University, P.O. Box 80203, Jeddah 21589 (Saudi Arabia); Omer, Muhammad [Institute of Chemical Sciences, University of Swat, Odigram, Swat, 19130, Khyber Pakhtunkhwa (Pakistan); Haider, Adnan [Department of Nano, Medical and Polymer Materials, College of Engineering, Yeungnam University, 280 Daehak-Ro, Gyeongsan 712-749 (Korea, Republic of); Khan, Farman Ullah; Asiri, Abdullah M. [Department of Chemistry, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21589 (Saudi Arabia); Center of Excellence for Advanced Materials Research (CEAMR), King Abdulaziz University, P.O. Box 80203, Jeddah 21589 (Saudi Arabia)

    2016-11-30

    Highlights: • Chitosan (CS) coating layer was applied on the surface of cellulose microfibers mat (CMM). • The CS coating layer was used to uptake the Copper (Cu) ions which were converted to nanoparticles. • The Cu/CS-CMM was demonstrated as catalyst in nitrophenols and cresyl blue reductions. • The rate constants for 2-nitrophenol, 4-nitrophenol and cresyl blue were 1.2 × 10{sup −3} s{sup −1}, 2.1 × 10{sup −3} s {sup −1} and, 1.3 × 10{sup −3} s{sup −1}, respectively. • The used catalyst was easily recovered by just pulling the strip from solutions. - Abstract: In this report, chitosan (CS) was adhered on cellulose microfiber mat (CMM) to prepare CS-CMM. This was used as host for copper (Cu) nanoparticles preparation. After adsorption of Cu{sup 2+} ions from an aqueous solution of CuSO{sub 4}, the metal ions entrapped in CS coating layer was treated with sodium borohydride (NaBH{sub 4}) to prepare Cu nanoparticles loaded CS-CMM (Cu/CS-CMM). Fourier transform infrared spectroscopy, and X-ray diffraction confirmed the formation of Cu/CS-CMM hybrid. Scanning electron microscopy analysis was performed to reveal the morphology of the prepared catalyst. The prepared Cu/CS-CMM was employed as a catalyst for the degradation of nitro-aromatic compounds of 2-nitrophenol (2NP) and 4-nitrophenol (4NP) as well as an organic cresyl blue (CB) dye. Remarkably, the turnover frequency in the case of 2NP and 4NP using Cu/CS-CMM reaches 103.3 and 88.6 h{sup −1}, outperforming previously reported Cu nanoparticles immobilized in hydrogel-based catalytic systems. The rate constants for 2NP, 4NP and CB were 1.2 × 10{sup −3} s{sup −1}, 2.1 × 10{sup −3} s{sup −1} and, 1.3 × 10{sup −3} s{sup −1}, respectively. Besides, we discussed the separation of the catalyst from the reaction mixture and its re-usability.

  9. Formation, Activity and Growth of Copper Nanoparticles in Methanol Synthesis Catalysts

    NARCIS (Netherlands)

    van den Berg, R.

    2016-01-01

    Supported metal catalysts play a pivotal role in the production of fuels and chemicals, in the purification of exhaust gases and in electrochemical energy conversion systems. Further improvement of these materials requires a fundamental understanding of the processes involved in the synthesis, the

  10. Palladium Nanoparticles Immobilized on Individual Calcium Carbonate Plates Derived from Mussel Shell Waste: An Ecofriendly Catalyst for the Copper-Free Sonogashira Coupling Reaction.

    Science.gov (United States)

    Saetan, Trin; Lertvachirapaiboon, Chutiparn; Ekgasit, Sanong; Sukwattanasinitt, Mongkol; Wacharasindhu, Sumrit

    2017-09-05

    The conversion of waste into high-value materials is considered an important sustainability strategy in modern chemical industries. A large volume of shell waste is generated globally from mussel cultivation. In this work, mussel shell waste (Perna viridis) is transformed into individual calcium carbonate plates (ICCPs) and is applied as a support for a heterogeneous catalyst. Palladium nanoparticles (3-6 nm) are deposited with an even dispersion on the ICCP surface, as demonstrated by X-ray diffraction and scanning electron microscopy. Using this system, Sonogashira cross-coupling reactions between aryl iodides and terminal acetylenes were accomplished in high yields with the use of 1 % Pd/ICCP in the presence of potassium carbonate without the use of any copper metal or external ligand. The Pd/ICCP catalyst could also be reused up to three times and activity over 90 % was maintained with negligible Pd-metal leaching. This work demonstrates that mussel shell waste can be used as an inexpensive and effective support for metal catalysts in coupling reactions, as demonstrated by the successful performance of the Pd-catalyzed, copper-free Sonogashira cross-coupling process. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Selective recovery of catalyst layer from supporting matrix of ceramic-honeycomb-type automobile catalyst.

    Science.gov (United States)

    Kim, Wantae; Kim, Boungyoung; Choi, Doyoung; Oki, Tatsuya; Kim, Sangbae

    2010-11-15

    Natural resources of platinum group metals (PGMs) are limited and their demand is increasing because of their extensive uses in industrial applications. The low rate of production of PGMs due to low concentration in the related natural ores and high cost of production have made the recovery of PGMs from previously discarded catalytic converters a viable proposition. The ceramic-honeycomb-type automobile catalytic converter contains appreciable amount of PGMs. These valuable substances, which are embedded in the catalyst layer and covered on the surface of the supporting matrix, were selectively recovered by attrition scrubbing. The attrition scrubbing was effective for the selective recovery of catalyst layer. The process was convinced as the comminution and separation process by physical impact and shearing action between particles in the scrubbing vessel. The catalyst layer was dislodged from the surface of the supporting matrix into fine particles by attrition scrubbing. The recovery of Al(2)O(3) and total PGMs in the fraction less than 300 μm increased with the residence time whereas their contents in the recovered materials slightly decreased. The interparticle scrubbing became favorable when the initial input size increased. However, the solid/liquid ratio in the mixing vessel was slightly affected by the low density of converter particles. Copyright © 2010 Elsevier B.V. All rights reserved.

  12. Preferential oxidation of CO in excess H2 over CuO/CeO2 catalysts: Performance as a function of the copper coverage and exposed face present in the CeO2 support

    DEFF Research Database (Denmark)

    Monte, M.; Gamarra, D.; López Cámara, A.

    2014-01-01

    CuO/CeO2 catalysts where the support has different nanoparticle shapes exposing different lattice planes are examined for the preferential oxidation of CO in the presence of excess H2 (CO-PROX reaction) in operando DRIFTS conditions. Even for catalysts with same surface concentration of Cu...... the selectivity for CO2 formation is found close to 100% up to higher temperatures when the support is in form of nanocubes (exposing the less stable (001) lattice planes). DRIFTS data allow relating this to a higher stability of the Cu species forming the Cu+ carbonyls associated to the high activity...

  13. Effect of tungsten carbide in carbon Pt catalyst support on electrochemical oxygen reduction in acid solution

    Directory of Open Access Journals (Sweden)

    Obradović Maja D.

    2013-01-01

    Full Text Available Tungsten carbide was synthesized by calcination of carbon cryogel with embedded tungsten in a form of metatungstate. This material was used as a support for Pt nanoparticles. XRD pattern of W-C support indicates the presence of WC, W2C, and unreacted W, as well as graphitized carbon. According to the previous TEM analysis of W-C support, it contains particles with core-shell structure, where W particle was covered with the shell of a mixture of WC and W2C. The average Pt grain size calculated from XRD pattern was about 6 nm. Cyclic voltammogram of W-C support was recorded within potential range relevant for its application as a catalyst support in fuel cells. Pair of anodic/cathodic peaks close to the negative potential limit could be ascribed to the intercalation of hydrogen within hydrous tungsten oxide, which is always present on the surface of WC in aqueous solutions. Cyclic voltammogram of Pt/W-C indicated that tungsten oxide species are present on tungsten carbide shell as well as on the surface of Pt nanoparticles. Pt surface is only partially covered by hydrous tungsten oxide. Hydrogen intercalation in hydrous tungsten oxide is enhanced in the presence of Pt nanoparticles. Also, the presence of hydrated tungsten oxide leads to the decrease of OH chemisorbed on Pt surface. Stripping of underpotentially deposited copper was used for the assessment of Pt surface area and the specific surface area of Pt was estimated to 41 m2 g-1. Electrochemical oxygen reduction reaction was examined on the synthesized Pt/W-C catalyst and compared with the results on the commercial Pt/C catalyst. It was found that the current densities at Pt/W-C are almost double as those on Pt/C. The Tafel plots for both catalysts are characterized with two Tafel slopes: -0.060 V dec-1 at low current densities, and -0.120 V dec-1 at high current densities. From the rotational dependence of the reaction rate, it was found that oxygen reduction on both Pt/W-C and Pt

  14. wet oxidation of maleic acid by a pumice supported copper

    African Journals Online (AJOL)

    Mgina

    Pumice supported Cu (II) Schiff base catalysts were prepared by surface chemical modification followed by complexation with Cu (II) acetate. ... chemistry of particular pumice does affect both the rate as well as the extent of cyanide .... maleic acid into the reactor and making the solution to 350 ml using distilled water.

  15. CO hydrogenation on supported molybdenum catalysts: effects of support on specific activities of reduced and sulfided catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Concha, B.E.; Bartholomew, G.L.; Bartholomew, C.H.

    1984-10-01

    A reaction temperature of 350/sup 0/C was chosen to minimize carbon formation and to allow sufficient conversion of CO. The initial specific activity of Mo/SiO/sub 2/ is significantly higher than that of the other reduced supported catalysts. The order of decreasing specific activity is Mo/SiO/sub 2/ > Mo/Al/sub 2/O/sub 3/ > Mo/C > Mo/CeO/sub 2/. For a reaction period of 20-25 h, the reduced Mo/SiO/sub 2/ activity decreased by 70% compared to 20-30% for the other catalysts. Initial specific activities of MoS/sub 2/ and sulfided Mo/Al/sub 2/O/sub 3/, Mo/SiO/sub 2/, and Mo/CeO/sub 2/ were similar and higher by factors of 6-8 than that of the Mo/C. With the exception of Mo/C, the mass-based activities of the freshly sulfided catalysts correlated linearly with oxygen uptake. Compared to freshly reduced catalysts, the activities of the sulfided Mo/SiO/sub 2/ and Mo/C were lower, that of Mo/Al/sub 2/O/sub 3/ about the same, and that of Mo/CeO/sub 2/ greater. Activities of the sulfided were generally stable during 20-25 h of reaction. 25 references, 1 figure, 2 tables.

  16. Capacitive electronic metal-support interactions: Outer surface charging of supported catalyst particles

    Science.gov (United States)

    Binninger, Tobias; Schmidt, Thomas J.; Kramer, Denis

    2017-10-01

    Electronic metal-support interactions (EMSI) in catalysis are commonly rationalized in terms of an electron transfer between support material and supported metal catalyst particles. This general perspective, however, cannot fully explain experimentally observed EMSI for metallic nanoparticulate catalysts, because the strong charge screening of metals should locally confine effects of direct electronic interaction with the support to the catalyst-support interface (CSI), which, apart from the perimeter, is largely inaccessible for catalysis reactants. The concept of capacitive EMSI is proposed here for catalyst particles at the nanometer scale, where electronic equilibration results in a long-range charging of the catalytically active outer surface (CAOS) bypassing the expected strong metallic charge screening, which is confirmed and quantified by electrostatic and density functional theory simulations revealing a strong dependence on the coverage of the support surface with catalyst particles. This long-range charge transfer leads to a shift of the local work function at the CAOS. In order to describe the catalytic consequences, an amendment of d -band theory in terms of `d -band + work function' is proposed. Furthermore, the charging of remote catalytic sites at the CAOS scales with the relative dielectric constant of the surrounding medium, and it is concluded that EMSI can have surprisingly strong influence especially in the presence of a strongly polarizable dielectric.

  17. Copper-cerium oxides supported on carbon nanomaterial for preferential oxidation of carbon monoxide

    Institute of Scientific and Technical Information of China (English)

    高美怡; 江楠; 赵宇宏; 徐长进; 苏海全; 曾尚红

    2016-01-01

    The CuxO-CeO2/Fe@CNSs, CuxO-CeO2/MWCNTs-Co and CuxO-CeO2/MWCNTs-Ni catalysts were prepared by the im-pregnation method and characterized by transmission electron microscopy, scanning electron microscopy, X-ray powder diffrac-tion, H2-temperature programmed reduction and N2 adsorption-desorption techniques. It was found that the Fe nanoparticles were encapsulated into the multi-layered carbon nanospheres (CNSs). However, the multi-wall carbon nanotubes (MWCNTS) were generated on the Co/Al2O3 and Ni/Al2O3 precursor. The addition of carbon nanomaterial as supports could improve structural properties and low-temperature activity of the CuO-CeO2 catalyst, and save the used amount of metal catalysts in the temperature range with high selectivity for CO oxidation. The copper-cerium oxides supported on carbon nanomaterial had good resistence to H2O and CO2.

  18. Marine sponge skeleton photosensitized by copper phthalocyanine: A catalyst for Rhodamine B degradation

    Directory of Open Access Journals (Sweden)

    Norman Małgorzata

    2016-01-01

    Full Text Available We present a combined approach to photo-assisted degradation processes, in which a catalyst, H2O2 and UV irradiation are used together to enhance the oxidation of Rhodamine B (RB. The heterogeneous photocatalyst was made by the process of adsorption of copper phthalocyanine tetrasulfonic acid (CuPC onto purified spongin-based Hippospongia communis marine sponge skeleton (HcS. The product obtained, CuPC-HcS, was investigated by a variety of spectroscopic (carbon-13 nuclear magnetic resonance 13C NMR, Fourier transform infrared spectroscopy FTIR, energy-dispersive X-ray spectroscopy EDS and microscopic techniques (scanning electron microscopy SEM, fluorescent and optical microscopy, as well as thermal analysis. The study confirms the stable combination of the adsorbent and adsorbate. For a 10 mg/L RB solution, the percentage degradation reached 95% using CuPC-HcS as a heterocatalyst. The mechanism of RB removal involves adsorption and photodegradation simultaneously.

  19. Crystalline Copper Phosphide Nanosheets as an Efficient Janus Catalyst for Overall Water Splitting.

    Science.gov (United States)

    Han, Ali; Zhang, Hanyu; Yuan, Ruihan; Ji, Hengxing; Du, Pingwu

    2017-01-25

    Hydrogen is essential to many industrial processes and could play an important role as an ideal clean energy carrier for future energy supply. Herein, we report for the first time the growth of crystalline Cu 3 P phosphide nanosheets on conductive nickel foam (Cu 3 P@NF) for electrocatalytic and visible light-driven overall water splitting. Our results show that the Cu 3 P@NF electrode can be used as an efficient Janus catalyst for both the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER). For OER catalysis, a current density of 10 mA/cm 2 requires an overpotential of only ∼320 mV and the slope of the Tafel plot is as low as 54 mV/dec in 1.0 M KOH. For HER catalysis, the overpotential is only ∼105 mV to achieve a catalytic current density of 10 mA cm -2 . Moreover, overall water splitting can be achieved in a water electrolyzer based on the Cu 3 P@NF electrode, which showed a catalytic current density of 10 mA/cm 2 under an applied voltage of ∼1.67 V. The same current density can also be obtained using a silicon solar cell under ∼1.70 V for both the HER and the OER. This new Janus Cu 3 P@NF electrode is made of inexpensive and nonprecious metal-based materials, which opens new possibilities based on copper to exploit overall water splitting for hydrogen production. To the best of our knowledge, such high performance of a copper-based water oxidation and overall water splitting catalyst has not been reported to date.

  20. Selective production of oxygenates from CO2 hydrogenation over mesoporous silica supported Cu-Ga nanocomposite catalyst

    KAUST Repository

    Huang, Kuo-Wei

    2017-11-23

    Carbon dioxide hydrogenation to oxygenates (methanol and dimethyl ether (DME)) was investigated over bifunctional supported copper catalysts promoted with gallium (Ga). Supported Cu-Ga nanocomposite catalysts were characterized by X-ray diffraction, transmission electron microscopy with energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy and H2 temperature programmed reduction. In comparison with Cu-SBA-15 based catalysts, Ga promoted catalysts prepared by the urea deposition method (CuGa/SBA-15-UDP) was found active and selective for CO2 hydrogenation to oxygenates. The use of Ga as the promoter showed increased acidic sites as confirmed by the NH3-TPD, Pyridine-IR and 2,6-lutidine-IR studies. The favorable effect of Ga on CO2 conversion and selectivity to oxygenate may come from the strong interaction of Ga with silica, which is responsible for the enhanced metal surface area, formation of nanocomposite and metal dispersion. Notably, incorporation of Ga to Cu/SiO2 showed a several-fold higher rate for methanol formation (13.12 mol/gCu·sec) with a reasonable rate for the DME formation (2.15 mol/gCu·sec) as compared to those of Cu/SiO2 catalysts.

  1. Redox properties and VOC oxidation activity of Cu catalysts supported on Ce₁-xSmxOδ mixed oxides.

    Science.gov (United States)

    Konsolakis, Michalis; Carabineiro, Sónia A C; Tavares, Pedro B; Figueiredo, José L

    2013-10-15

    A series of Cu catalysts supported on Ce1-xSmxOδ mixed oxides with different molar contents (x=0, 0.25, 0.5, 0.75 and 1), was prepared by wet impregnation and evaluated for volatile organic compounds (VOC) abatement, employing ethyl acetate as model molecule. An extensive characterization study was undertaken in order to correlate the morphological, structural and surface properties of catalysts with their oxidation activity. The optimum performance was obtained with Cu/CeO2 catalyst, which offers complete conversion of ethyl acetate into CO2 at temperatures as low as 260°C. The catalytic performance of Cu/Ce1-xSmxOδ was interpreted on the basis of characterization studies, showing that incorporation of samarium in ceria has a detrimental effect on the textural characteristics and reducibility of catalysts. Moreover, high Sm/Ce atomic ratios (from 1 to 3) resulted in a more reduced copper species, compared to CeO2-rich supports, suggesting the inability of these species to take part in the redox mechanism of VOC abatement. Sm/Ce surface atomic ratios are always much higher than the nominal ratios indicating an impoverishment of catalyst surface in cerium oxide, which is detrimental for VOC activity. Copyright © 2013 Elsevier B.V. All rights reserved.

  2. Enhanced catalytic toluene oxidation by interaction between copper oxide and manganese oxide in Cu-O-Mn/γ-Al2O3 catalysts

    Science.gov (United States)

    Wang, Hongpei; Lu, Yiyuan; Han, YuXiang; Lu, Chunliang; Wan, Haiqin; Xu, Zhaoyi; Zheng, Shourong

    2017-10-01

    Toward catalytic oxidation of toluene, Cu-O-Mn/γ-Al2O3 catalysts with series molar ratios of Cu/Mn were prepared using an impregnation method. The surface structure and chemical state of the as-prepared catalysts were characterized by the combination of X-ray diffraction (XRD), N2 adsorption/desorption, UV-vis spectroscopy (UV-vis), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and H2 temperature programmed reduction (H2-TPR). The results demonstrated that copper oxide and manganese oxide were highly dispersed on the γ-Al2O3 support. Meanwhile, there is an interaction between copper oxide and manganese oxide, depending on the atomic ratio of Cu/Mn. At the ratio of Cu/Mn = 1:1.5, the interaction between Cu and Mn oxides reached the strongest, thus leading to the highest catalytic activity and turn over frequency among all of the ratios. The temperature for complete combustion of toluene over the strongest interaction sample could be 350 °C, which could further decrease to 300 °C when tuning the loading amount of Cu and Mn. Findings in this work are important for the design of efficient catalyst by tuning the interaction between each components.

  3. Magnetic Carbon Supported Palladium Nanoparticles: An Efficient and Sustainable Catalyst for Hydrogenation Reactions

    Science.gov (United States)

    Magnetic carbon supported Pd catalyst has been synthesized via in situ generation of nanoferrites and incorporation of carbon from renewable cellulose via calcination; the catalyst can be used for the hydrogenation of alkenes and reduction of aryl nitro compounds.

  4. High-efficiency palladium catalysts supported on ppy-modified C60 for formic acid oxidation.

    Science.gov (United States)

    Bai, Zhengyu; Yang, Lin; Guo, Yuming; Zheng, Zhi; Hu, Chuangang; Xu, Pengle

    2011-02-14

    A facile preparation of polypyrrole-modified fullerene supported Pd nanoparticles catalyst is introduced; electrochemical measurements demonstrate that the obtained Pd/ppy-C(60) catalyst shows a good electrocatalytic activity and stability for the oxidation of formic acid.

  5. Synthesis and Characterization of Cluster-Derived Supported Bimetallic Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Adams, Richard D; Amiridis, Michael D

    2008-10-10

    New procedures have been developed for synthesizing di- and tri-metallic cluster complexes. The chemical properties of the new complexes have been investigated, particularly toward the activation of molecular hydrogen. These complexes were then converted into bi- and tri-metallic nanoparticles on silica and alumina supports. These nanoparticles were characterized by electron microscopy and were then tested for their ability to produce catalytic hydrogenation of unsaturated hydrocarbons and for the preferential oxidation of CO in the presence of hydrogen. The bi- and tri-metallic nanoparticles exhibited far superior activity and selectivity as hydrogenation catalysts when compared to the individual metallic components. It was found that the addition of tin greatly improved the selectivity of the catalysts for the hydrogenation of polyolefins. The addition of iron improves the catalysts for the selective oxidation of CO by platinum in the presence of hydrogen. The observations should lead to the development of lower cost routes to molecules that can be used to produce polymers and plastics for use by the general public and for procedures to purify hydrogen for use as an alternative energy in the hydrogen economy of the future.

  6. Biotemplated Palladium Catalysts Can Be Stabilized on Different Support Materials

    KAUST Repository

    Yates, Matthew D.

    2014-07-30

    © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Sustainably biotemplated palladium catalysts generated on different carbon-based support materials are examined for durability under electrochemical (oxidative) and mechanical-stress conditions. Biotemplated catalysts on carbon paper under both stresses retain 95% (at 0.6V) of the initial catalytic activity as opposed to 70% for carbon cloth and 60% for graphite. Graphite electrodes retain 95% of initial catalytic activity under a single stress. Using electrodeposited polyaniline (PANI) and polydimethylsiloxane binder increases the current density after the stress tests by 22%, as opposed to a 30% decrease for Nafion. PANI-coated electrodes retain more activity than carbon-paper electrodes under elevated mechanical (94 versus 70%) or increased oxidative (175 versus 62%) stress. Biotemplated catalytic electrodes may be useful alternatives to synthetically produce catalysts for some electrochemical applications. Sustainable electrode fabrication: The biotemplated synthesis of catalytic porous electrodes is a sustainable process and, according to the results of durability tests under electrochemical and mechanical stress, these electrodes (e.g. the Pd/carbon paper electrode shown in the picture) are durable enough to replace catalytic electrodes based on synthetic materials in certain applications.

  7. Adsorbate-mediated strong metal-support interactions in oxide-supported Rh catalysts

    Science.gov (United States)

    Matsubu, John C.; Zhang, Shuyi; Derita, Leo; Marinkovic, Nebojsa S.; Chen, Jingguang G.; Graham, George W.; Pan, Xiaoqing; Christopher, Phillip

    2017-02-01

    The optimization of supported metal catalysts predominantly focuses on engineering the metal site, for which physical insights based on extensive theoretical and experimental contributions have enabled the rational design of active sites. Although it is well known that supports can influence the catalytic properties of metals, insights into how metal-support interactions can be exploited to optimize metal active-site properties are lacking. Here we utilize in situ spectroscopy and microscopy to identify and characterize a support effect in oxide-supported heterogeneous Rh catalysts. This effect is characterized by strongly bound adsorbates (HCOx) on reducible oxide supports (TiO2 and Nb2O5) that induce oxygen-vacancy formation in the support and cause HCOx-functionalized encapsulation of Rh nanoparticles by the support. The encapsulation layer is permeable to reactants, stable under the reaction conditions and strongly influences the catalytic properties of Rh, which enables rational and dynamic tuning of CO2-reduction selectivity.

  8. Studies of Immobilized Homogeneous Metal Catalysts on Silica Supports

    Energy Technology Data Exchange (ETDEWEB)

    Stanger, Keith James [Iowa State Univ., Ames, IA (United States)

    2003-01-01

    The tethered, chiral, chelating diphosphine rhodium complex, which catalyzes the enantioselective hydrogenation of methyl-α-acetamidocinnamate (MAC), has the illustrated structure as established by 31P NMR and IR studies. Spectral and catalytic investigations also suggest that the mechanism of action of the tethered complex is the same as that of the untethered complex in solution. The rhodium complexes, [Rh(COD)H]4, [Rh(COD)2]+BF4-, [Rh(COD)Cl]2, and RhCl3• 3H2O, adsorbed on SiO2 are optimally activated for toluene hydrogenation by pretreatment with H2 at 200 C. The same complexes on Pd-SiO2 are equally active without pretreatments. The active species in all cases is rhodium metal. The catalysts were characterized by XPS, TEM, DRIFTS, and mercury poisoning experiments. Rhodium on silica catalyzes the hydrogenation of fluorobenzene to produce predominantly fluorocyclohexane in heptane and 1,2-dichloroethane solvents. In heptane/methanol and heptane/water solvents, hydrodefluorination to benzene and subsequent hydrogenation to cyclohexane occurs exclusively. Benzene inhibits the hydrodefluorination of fluorobenzene. In DCE or heptane solvents, fluorocyclohexane reacts with hydrogen fluoride to form cyclohexene. Reaction conditions can be chosen to selectively yield fluorocyclohexane, cyclohexene, benzene, or cyclohexane. The oxorhenium(V) dithiolate catalyst [-S(CH2)3s-]Re(O)(Me)(PPh3) was modified by linking it to a tether that could be attached to a silica support. Spectroscopic investigation and catalytic oxidation reactivity showed the heterogenized catalyst's structure and reactivity to be similar to its homogeneous analog. However, the immobilized catalyst offered additional advantages of recyclability, extended stability, and increased resistance to deactivation.

  9. Bromate catalytic reduction in continuous mode using metal catalysts supported on monoliths coated with carbon nanofibers

    OpenAIRE

    Marco, Yanila; Garcia-Bordeje, Enrique; Franch, Cristina; Palomares, Antonio E.; Yuranova, Tatiana; Kiwi-Minsker, Lioubov

    2013-01-01

    Nitrogen-doped and un-doped carbon nanofibers layers, denoted as N-CNFs and CNFs respectively, coating the walls of cordierite monoliths have been used as support for Pd and Ru catalyst. They have been tested in bromate reduction in batch and continuous operation employing different reactor configurations. The CNF/monolith catalysts were benchmarked with Pd catalyst on CNF coated on another structured support, namely sintered metal fibers. CNF/monolith is a robust, active and stable catalyst ...

  10. Kinetics of carbon monoxide oxidation over modified supported CuO catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Loc, Luu Cam; Tri, Nguyen; Cuong, Hoang Tien; Thoang, Ho Si [Vietnam Academy of Science and Technology (VAST), Ho Chi Minh City (Viet Nam). Inst. of Chemical Technology; Agafonov, Yu.A.; Gaidai, N.A.; Lapidus, A.L. [Russian Academy of Sciences, Moscow (Russian Federation). N.D. Zelinsky Institute of Organic Chemistry

    2013-11-01

    The following supported on {gamma}-Al{sub 2}O{sub 3} catalysts: 10(wt.)%CuO (CuAl), 10%CuO+10%Cr{sub 2}O{sub 3} (CuCrAl) and 10%CuO+20%CeO{sub 2} (CuCeAl) were under the investigation. Physico-chemical characteristics of the catalysts were determined by the methods of BET, X-ray Diffraction (XRD), and Temperature-Programmed Reduction (TPR). A strong interaction of copper with support in CuAl resulted in the formation of low active copper aluminates. The bi-oxide CuCrAl was more active than CuAl owing to the formation of high catalytically active spinel CuCr{sub 2}O{sub 4}. The fact of very high activity of the sample CuCeAl can be explained by the presence of the catalytically active form of CuO-CeO{sub 2}-Al{sub 2}O{sub 3}. The kinetics of CO total oxidation was studied in a gradientless flow-circulating system at the temperature range between 200 C and 270 C. The values of initial partial pressures of carbon monoxide (P{sup o}{sub CO}), oxygen (P{sup o}{sub O2}), and specially added carbon dioxide (P{sup o}{sub CO{sub 2}}) were varied in ranges (hPa): 10 / 45; 33 / 100, and 0 / 30, respectively. (orig.)

  11. Supercritical Antisolvent Precipitation of Amorphous Copper-Zinc Georgeite and Acetate Precursors for the Preparation of Ambient-Pressure Water-Gas-Shift Copper/Zinc Oxide Catalysts.

    Science.gov (United States)

    Smith, Paul J; Kondrat, Simon A; Carter, James H; Chater, Philip A; Bartley, Jonathan K; Taylor, Stuart H; Spencer, Michael S; Hutchings, Graham J

    2017-05-10

    A series of copper-zinc acetate and zincian georgeite precursors have been produced by supercritical CO2 antisolvent (SAS) precipitation as precursors to Cu/ZnO catalysts for the water gas shift (WGS) reaction. The amorphous materials were prepared by varying the water/ethanol volumetric ratio in the initial metal acetate solutions. Water addition promoted georgeite formation at the expense of mixed metal acetates, which are formed in the absence of the water co-solvent. Optimum SAS precipitation occurs without water to give high surface areas, whereas high water content gives inferior surface areas and copper-zinc segregation. Calcination of the acetates is exothermic, producing a mixture of metal oxides with high crystallinity. However, thermal decomposition of zincian georgeite resulted in highly dispersed CuO and ZnO crystallites with poor structural order. The georgeite-derived catalysts give superior WGS performance to the acetate-derived catalysts, which is attributed to enhanced copper-zinc interactions that originate from the precursor.

  12. SiC nanocrystals as Pt catalyst supports for fuel cell applications

    DEFF Research Database (Denmark)

    Dhiman, Rajnish; Johnson, Erik; Skou, Eivind Morten

    2013-01-01

    on the nanocrystals of SiC-SPR and SiC-NS by the polyol method. The SiC substrates are subjected to an acid treatment to introduce the surface groups, which help to anchor the Pt nano-catalysts. These SiC based catalysts have been found to have a higher electrochemical activity than commercially available Vulcan......A robust catalyst support is pivotal to Proton Exchange Membrane Fuel Cells (PEMFCs) to overcome challenges such as catalyst support corrosion, low catalyst utilization and overall capital cost. SiC is a promising candidate material which could be applied as a catalyst support in PEMFCs. Si...... based catalysts (BASF & HISPEC). These promising results signal a new era of SiC based catalysts for fuel cell...

  13. Supported fischer-tropsch catalyst and method of making the catalyst

    Science.gov (United States)

    Dyer, Paul N.; Pierantozzi, Ronald; Withers, Howard P.

    1987-01-01

    A Fischer-Tropsch catalyst and a method of making the catalyst for a Fischer-Tropsch 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 is disclosed. In general, the selective and notably stable catalyst, consist 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 a Fischer-Tropsch metal catalyst, such as cobalt, iron or ruthenium carbonyl. Reactions with air and water and calcination are specifically avoided in the catalyst preparation procedure.

  14. A high-performance catalyst support for methanol oxidation with graphene and vanadium carbonitride.

    Science.gov (United States)

    Huang, Taizhong; Mao, Shun; Zhou, Guihua; Zhang, Zhaoliang; Wen, Zhenhai; Huang, Xingkang; Ci, Suqin; Chen, Junhong

    2015-01-28

    In this study, a graphene-vanadium carbonitride (G-V(C, N)) hybrid is reported as a novel support for the Pt catalyst in methanol oxidation. The catalytic activity of the Pt/G-V(C, N) hybrid for methanol oxidation is greatly enhanced compared with that of a commercial Pt/C catalyst with carbon black as the catalyst support. The outstanding catalytic activity of the Pt/G-V(C, N) catalyst suggests the potential of using graphene-metal carbonitride as the catalyst support in fuel cells.

  15. MASS TRANSFER IN PORE STRUCTURES OF SUPPORTED CATALYSTS

    Directory of Open Access Journals (Sweden)

    F.R.C. Silva

    1997-09-01

    Full Text Available The effects of gas-solid interaction and mass transfer in fixed-bed systems of supported catalysts were analyzed for g -Al2O3 (support and Cu/g -Al2O3 (catalyst systems. Evaluations of the mass transfer coefficients in the macropores and of the diffusivity in the micropores, as formed by the crystallite agglomerates of the metallic phases, were obtained. Dynamic experiments with gaseous tracers permitted the quantification of the parameters based on models for these two pore structures. With a flow in a range of 18 cm3 s-1 to 39.98 cm3 s-1 at 45oC, 65oC and 100oC, mass transfer coefficients km =4.33x10-4 m s-1 to 7.38x10-4 m s-1 for macropore structures and diffusivities Dm =1.29x10-11 m2 s-1 to 5.35x10-11 m2 s-1 for micropore structures were estimated

  16. Selective oxidation of propylene to acrolein by silica-supported bismuth molybdate catalysts

    DEFF Research Database (Denmark)

    Duc, Duc Truong; Ha, Hanh Nguyen; Fehrmann, Rasmus

    2011-01-01

    Silica-supported bismuth molybdate catalysts have been prepared by impregnation, structurally characterized and examined as improved catalysts for the selective oxidation of propylene to acrolein. Catalysts with a wide range of loadings (from 10 to 90 wt%) of beta bismuth molybdate (β-Bi2Mo2O9...

  17. Effects of catalyst-support materials on the performance of fuel cells

    CSIR Research Space (South Africa)

    Ejikeme, PM

    2016-07-01

    Full Text Available as catalyst-supports in fuel cells (FCs) leading to electrical isolation of the catalyst particles and Ostwald ripening as well as decrease in the electrochemically-active surface area (EASA) of the catalyst. Although the chapter summarizes much...

  18. Silica gel-Supported Palladium Catalyst for the Acyl Sonogashira Reaction

    Energy Technology Data Exchange (ETDEWEB)

    Hossain, Shahin; Park, Jihoon; Park, Minkyu; Jin, Myungjong [Inha Univ., Incheon (Korea, Republic of)

    2013-06-15

    We have demonstrated an efficient and eco-friendly procedure for the synthesis of ynones using silica supported thiol-palladium complex as a recyclable catalyst under copper free mild reaction conditions. The material was synthesized by post grafting of 3-mercaptopropyltrimethoxysilane on amorphous silica and subsequently Pd(II) attached onto thiol groups. This synthetic method has notable advantages because it involves easily available, less costly and produces an easily recyclable catalyst in high yields of the products. The mild reaction conditions encouraged us to further extension for the development of novel multicomponent reactions. Thus we have explained the three component synthesis of pyrazoles in one-pot fashion with good yields. Specifically, this simple procedure for the ynone synthesis and this approach to synthesize N-containing heterocycles may be valuable tool in future. The acyl Sonogashira reaction between acyl chlorides and terminal alkynes is one of the most useful method for the preparation of ynones which are important intermediates to prepare versatile pharmaceutically and biologically active heterocyclic compounds such as pyrroles, pyrazoles, furans, furanones, isoxazoles, pyrimidines, quinolines, indolizidinones.

  19. Influence of reaction parameters on the hydrogenolysis of hydroxymatairesinol over carbon nanofibre supported palladium catalysts

    OpenAIRE

    Bernas, H.; Plomp, A.J.; Bitter, J.H.; Murzin, D.Y.

    2008-01-01

    The influence of catalyst particle size, stirring rate, catalyst mass (0.2–0.6 g), reaction temperature (60–70 C), and reactant concentration (1.3–4 mmol/L, with constant reactant/catalyst ratio) on the hydrogenolysis of the lignan hydroxymatairesinol (HMR) to matairesinol (MAT) was studied under hydrogen atmosphere using a carbon nanofibre supported palladium catalyst. When the temperature or HMR concentration was increased, the reaction rate increased as expected. However, the reaction rate...

  20. Supported metal catalysts for alcohol/sugar alcohol steam reforming.

    Science.gov (United States)

    Davidson, Stephen D; Zhang, He; Sun, Junming; Wang, Yong

    2014-08-21

    Despite extensive studies on hydrogen production via steam reforming of alcohols and sugar alcohols, catalysts typically suffer a variety of issues from poor hydrogen selectivity to rapid deactivation. Here, we summarize recent advances in fundamental understanding of functionality and structure of catalysts for alcohol/sugar alcohol steam reforming, and provide perspectives on further development required to design highly efficient steam reforming catalysts.

  1. SELECTIVE HYDROGENATION OF CINNAMALDEHYDE WITH Pt AND Pt-Fe CATALYSTS: EFFECTS OF THE SUPPORT

    Directory of Open Access Journals (Sweden)

    A.B. da Silva

    1998-06-01

    Full Text Available Low-temperature reduced TiO2-supported Pt and Pt-Fe catalysts are much more active and selective for the liquid–phase hydrogenation of cinnamaldehyde to unsaturated cinnamyl alcohol than the corresponding carbon-supported catalysts. High-temperature reduced catalysts, where the SMSI effect should be present, are almost inactive for this reaction. There is at present no definitive explanation for this effect but an electronic metal-support interaction is most probably involved.

  2. A kinetic and spectroscopic study on the copper catalyzed oxidative coupling polymerization of 2,6-dimethylphenol. X-ray structure of the catalyst precursor tetrakis(N-methylimidazole)bis(nitrato)copper(II)

    NARCIS (Netherlands)

    Baesjou, PJ; Driessen, WL; Challa, G; Reedijk, J

    1996-01-01

    The complex of copper(II) nitrate with N-methylimidazole (Nmiz) ligand has been studied as a catalyst for the oxidative coupling of 2,6-dimethylphenol by means of kinetic and spectroscopic measurements. The order of the reaction in copper is fractional and depends on the N/Cu ratio and the base/Cu

  3. The Effect of Catalyst Support on the Decomposition of Methane to Hydrogen and Carbon

    Directory of Open Access Journals (Sweden)

    Sharif Hussein Sharif Zein Abdul Rahman Mohamed

    2012-10-01

    Full Text Available Decomposition of methane into carbon and hydrogen over Cu/Ni supported catalysts was investigated. The catalytic activities and the lifetimes of the catalysts were studied. Cu/Ni supported on TiO2 showed high activity and long lifetime for the reaction. Transmission electron microscopy (TEM studies revealed the relationship between the catalyst activity and the formation of the filamentous carbon over the catalyst after methane decomposition. While different types of filamentous carbon formed on the various Cu/Ni supported catalysts, an attractive carbon nanotubes was observed in the Cu/Ni supported on TiO2. Key Words:  Methane decomposition, carbon nanotube, Cu/Ni supported catalysts.

  4. Propene Hydroformylation by Supported Aqueous-phase Rh-NORBOS Catalysts

    DEFF Research Database (Denmark)

    Riisager, Anders; Eriksen, Kim Michael; Hjortkjær, Jes

    2003-01-01

    The gas-phase hydroformylation reaction of propene using supported aqueous-phase (SAP) Rh-NORBOS modified catalysts in a continuous flow reactor has been examined. SAP catalysts supported on six different support materials were made by wet impregnation using solutions of the precursor complex Rh...

  5. 'Shape effects' in metal oxide supported nanoscale gold catalysts.

    Science.gov (United States)

    Boucher, Matthew B; Goergen, Simone; Yi, Nan; Flytzani-Stephanopoulos, Maria

    2011-02-21

    We report the activity of shape-controlled metal oxide (CeO(2), ZnO and Fe(3)O(4)) supported gold catalysts for the steam reforming of methanol (SRM) and the water gas shift (WGS) reactions. Metal oxide nanoshapes, prepared by controlled hydrolysis and thermolysis methods, expose different crystal surfaces, and consequently disperse and stabilize gold differently. We observe that similar to gold supported on CeO(2) shapes exposing the {110} and {111} surfaces, gold supported on the oxygen-rich ZnO {0001} and Fe(3)O(4) {111} surfaces shows higher activity for the SRM and WGS reactions. While the reaction rates vary among the Au-CeO(2), Au-ZnO and Au-Fe(3)O(4) shapes, the apparent activation energies are similar, indicating a common active site. TPR data further indicate that the reaction lightoff coincides with the activation of Au-O-M species on the surface of all three oxide supports evaluated here. Different shapes contain a different number of binding sites for the gold, imparting different overall activity.

  6. TECHNOLOGIES OF DOPING OF CAST IRON THROUGH THE SLAG PHASE WITH USING OF THE SPENT NICKEL- AND COPPER-CONTAINING CATALYSTS

    Directory of Open Access Journals (Sweden)

    I. B. Provorova

    2015-01-01

    Full Text Available We have defined the regularities of the doping of cast iron through the slag phase of nickel and copper due to the waste catalysts using a carbonaceous reducing agent. We have justified the need to use the cast iron chips as a seed in the composition of the slag mixture. We have defined the dependence of the degree of extraction of nickel or copper from spent catalyst on the amount of the catalyst, on the basicity of the slag mixture, on the temperature and time of melting.

  7. Practical, economical, and eco-friendly starch-supported palladium catalyst for Suzuki coupling reactions.

    Science.gov (United States)

    Baran, Talat

    2017-06-15

    In catalytic systems, the support materials need to be both eco friendly and low cost as well as having high thermal and chemical stability. In this paper, a novel starch supported palladium catalyst, which had these outstanding properties, was designed and its catalytic activity was evaluated in a Suzuki coupling reaction under microwave heating with solvent-free and mild reaction conditions. The starch supported catalyst gave remarkable reaction yields after only 5min as a result of the coupling reaction of the phenyl boronic acid with 23 different substrates, which are bearing aril bromide, iodide, and chloride. The longevity of the catalyst was also investigated, and the catalyst could be reused for 10 runs. The starch supported Pd(II) catalyst yielded remarkable TON (up to 25,000) and TOF (up to 312,500) values by using a simple, fast and eco-friendly method. In addition, the catalytic performance of the catalyst was tested against different commercial palladium catalysts, and the green starch supported catalyst had excellent selectivity. The catalytic tests showed that the novel starch based palladium catalyst proved to be an economical and practical catalyst for the synthesis of biaryl compounds. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Influence of the support in selective CO oxidation on Pt catalysts for fuel cell applications

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Mariana M.V.M. [Escola de Quimica, Federal University of Rio de Janeiro, Centro de Tecnologia, Bloco E, sala 206, CEP 21940-900, Rio de Janeiro/RJ (Brazil); NUCAT/COPPE/UFRJ, Centro de Tecnologia, Bloco G, sala 228, CEP 21945-970, Rio de Janeiro/RJ (Brazil); Ribeiro, Nielson F.P.; Schmal, Martin [NUCAT/COPPE/UFRJ, Centro de Tecnologia, Bloco G, sala 228, CEP 21945-970, Rio de Janeiro/RJ (Brazil)

    2007-03-15

    One crucial requirement for the proton exchange membrane fuel cells (PEMFC) is to feed clean hydrogen to the anode, which is rapidly poisoned by traces of CO present from the upstream hydrocarbon reforming and water-gas shift processes. The removal of CO can be achieved by using catalysts able to selectively oxidize CO in the presence of excess hydrogen. Herein we report the effect of the support on Pt catalysts for total and selective oxidation (SELOX) of CO. The catalysts supported on ceria and zirconia presented higher activity than alumina and silica supported catalysts in SELOX reaction at low temperatures, but with lower CO conversions. (author)

  9. Effect of Copper Nanoparticles Dispersion on Catalytic Performance of Cu/SiO2 Catalyst for Hydrogenation of Dimethyl Oxalate to Ethylene Glycol

    Directory of Open Access Journals (Sweden)

    Yajing Zhang

    2013-01-01

    Full Text Available Cu/SiO2 catalysts, for the synthesis of ethylene glycol (EG from hydrogenation of dimethyl oxalate (DMO, were prepared by ammonia-evaporation and sol-gel methods, respectively. The structure, size of copper nanoparticles, copper dispersion, and the surface chemical states were investigated by X-ray diffraction (XRD, transmission electron microscopy (TEM, temperature-programmed reduction (TPR, and X-ray photoelectron spectroscopy (XPS and N2 adsorption. It is found the structures and catalytic performances of the catalysts were highly affected by the preparation method. The catalyst prepared by sol-gel method had smaller average size of copper nanoparticles (about 3-4 nm, better copper dispersion, higher Cu+/C0 ratio and larger BET surface area, and higher DMO conversion and EG selectivity under the optimized reaction conditions.

  10. Supported quantum clusters of silver as enhanced catalysts for reduction

    Directory of Open Access Journals (Sweden)

    Leelavathi Annamalai

    2011-01-01

    Full Text Available Abstract Quantum clusters (QCs of silver such as Ag7(H2MSA7, Ag8(H2MSA8 (H2MSA, mercaptosuccinic acid were synthesized by the interfacial etching of Ag nanoparticle precursors and were loaded on metal oxide supports to prepare active catalysts. The supported clusters were characterized using high resolution transmission electron microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, and laser desorption ionization mass spectrometry. We used the conversion of nitro group to amino group as a model reaction to study the catalytic reduction activity of the QCs. Various aromatic nitro compounds, namely, 3-nitrophenol (3-np, 4-nitrophenol (4-np, 3-nitroaniline (3-na, and 4-nitroaniline (4-na were used as substrates. Products were confirmed using UV-visible spectroscopy and electrospray ionization mass spectrometry. The supported QCs remained active and were reused several times after separation. The rate constant suggested that the reaction followed pseudo-first-order kinetics. The turn-over frequency was 1.87 s-1 per cluster for the reduction of 4-np at 35°C. Among the substrates investigated, the kinetics followed the order, SiO2 > TiO2 > Fe2O3 > Al2O3.

  11. Catalytic hydrothermal treatment of pulping effluent using a mixture of Cu and Mn metals supported on activated carbon as catalyst.

    Science.gov (United States)

    Yadav, Bholu Ram; Garg, Anurag

    2016-10-01

    The present study was performed to investigate the performance of activated carbon-supported copper and manganese base catalyst for catalytic wet oxidation (CWO) of pulping effluent. CWO reaction was performed in a high pressure reactor (capacity = 0.7 l) at temperatures ranging from 120 to 190 °C and oxygen partial pressures of 0.5 to 0.9 MPa with the catalyst concentration of 3 g/l for 3 h duration. With Cu/Mn/AC catalyst at 190 °C temperature and 0.9 MPa oxygen partial pressures, the maximum chemical oxygen demand (COD), total organic carbon (TOC), lignin, and color removals of 73, 71, 86, and 85 %, respectively, were achieved compared to only 52, 51, 53, and 54 % removals during the non-catalytic process. Biodegradability (in terms of 5-day biochemical oxygen demand (BOD5) to COD ratio) of the pulping effluent was improved to 0.38 from an initial value of 0.16 after the catalytic reaction. The adsorbed carbonaceous fraction on the used catalyst was also determined which contributed meager TOC reduction of 3-4 %. The leaching test showed dissolution of the metals (i.e., Cu and Mn) from the catalysts in the wastewater during CWO reaction at 190 °C temperature and 0.9 MPa oxygen partial pressures. In the future, the investigations should focus on the catalyst reusability.

  12. Supported Catalysts Useful in Ring-Closing Metathesis, Cross Metathesis, and Ring-Opening Metathesis Polymerization

    Directory of Open Access Journals (Sweden)

    Jakkrit Suriboot

    2016-04-01

    Full Text Available Ruthenium and molybdenum catalysts are widely used in synthesis of both small molecules and macromolecules. While major developments have led to new increasingly active catalysts that have high functional group compatibility and stereoselectivity, catalyst/product separation, catalyst recycling, and/or catalyst residue/product separation remain an issue in some applications of these catalysts. This review highlights some of the history of efforts to address these problems, first discussing the problem in the context of reactions like ring-closing metathesis and cross metathesis catalysis used in the synthesis of low molecular weight compounds. It then discusses in more detail progress in dealing with these issues in ring opening metathesis polymerization chemistry. Such approaches depend on a biphasic solid/liquid or liquid separation and can use either always biphasic or sometimes biphasic systems and approaches to this problem using insoluble inorganic supports, insoluble crosslinked polymeric organic supports, soluble polymeric supports, ionic liquids and fluorous phases are discussed.

  13. Crystalline niobia with tailored porosity as support for cobalt catalysts for the Fischer–Tropsch synthesis

    NARCIS (Netherlands)

    Hernández Mejía, C.; den Otter, J. H.; Weber, J. L.; de Jong, K. P.

    2017-01-01

    Structure and catalytic performance of niobia-supported cobalt catalysts were studied based on crystal phase, porosity and cobalt loading. Crystalline niobia as support proved to be a prerequisite to obtain highly active and selective Co/niobia Fischer–Tropsch catalysts, whereas amorphous niobia

  14. The role of support and promoter on the oxidation of sulfur dioxide using platinum based catalysts

    DEFF Research Database (Denmark)

    Koutsopoulos, Sotiris; Rasmussen, Søren Birk; Eriksen, Kim Michael

    2006-01-01

    The catalytic oxidation of SO2 to SO3 was studied over platinum based catalysts in the absence and the presence of dopants. The active metal was supported on silica gel or titania (anatase) by impregnation. The activities of the silica supported catalysts were found to follow the order PtRh/SiO2 ...

  15. Hydrogenation of CO2 on ZnO/Cu(100) and ZnO/Cu(111) Catalysts: Role of Copper Structure and Metal-Oxide Interface in Methanol Synthesis.

    Science.gov (United States)

    Palomino, Robert M; Ramírez, Pedro J; Liu, Zongyuan; Hamlyn, Rebecca; Waluyo, Iradwikanari; Mahapatra, Mausumi; Orozco, Ivan; Hunt, Adrian; Simonovis, Juan P; Senanayake, Sanjaya D; Rodriguez, José A

    2017-08-30

    The results of kinetic tests and ambient-pressure X-ray photoelectron spectroscopy (AP-XPS) show the important role played by a ZnO-copper interface in the generation of CO and the synthesis of methanol from CO2 hydrogenation. The deposition of nanoparticles of ZnO on Cu(100) and Cu(111), θoxi < 0.3 monolayer, produces highly active catalysts. The catalytic activity of these systems increases in the sequence: Cu(111) < Cu(100) < ZnO/Cu(111) < ZnO/Cu(100). The structure of the copper substrate influences the catalytic performance of a ZnO-copper interface. Furthermore, size and metal-oxide interactions affect the chemical and catalytic properties of the oxide making the supported nanoparticles different from bulk ZnO. The formation of a ZnO-copper interface favors the binding and conversion of CO2 into a formate intermediate that is stable on the catalyst surface up to temperatures above 500 K. Alloys of Zn with Cu(111) and Cu(100) were not stable at the elevated temperatures (500-600 K) used for the CO2 hydrogenation reaction. Reaction with CO2 oxidized the zinc, enhancing its stability over the copper substrates.

  16. Hydrodechlorination of Tetrachloromethane over Palladium Catalysts Supported on Mixed MgF₂-MgO Carriers.

    Science.gov (United States)

    Bonarowska, Magdalena; Wojciechowska, Maria; Zieliński, Maciej; Kiderys, Angelika; Zieliński, Michał; Winiarek, Piotr; Karpiński, Zbigniew

    2016-11-25

    Pd/MgO, Pd/MgF₂ and Pd/MgO-MgF₂ catalysts were investigated in the reaction of CCl₄ hydrodechlorination. All the catalysts deactivated in time on stream, but the degree of deactivation varied from catalyst to catalyst. The MgF₂-supported palladium with relatively large metal particles appeared the best catalyst, characterized by good activity and selectivity to C₂-C₅ hydrocarbons. Investigation of post-reaction catalyst samples allowed to find several details associated with the working state of hydrodechlorination catalysts. The role of support acidity was quite complex. On the one hand, a definite, although not very high Lewis acidity of MgF₂ is beneficial for shaping high activity of palladium catalysts. The MgO-MgF₂ support characterized by stronger Lewis acidity than MgF₂ contributes to very good catalytic activity for a relatively long reaction period (~5 h) but subsequent neutralization of stronger acid centers (by coking) eliminates them from the catalyst. On the other hand, the role of acidity evolution, which takes place when basic supports (like MgO) are chlorided during HdCl reactions, is difficult to assess because different events associated with distribution of chlorided support species, leading to partial or even full blocking of the surface of palladium, which plays the role of active component in HdCl reactions.

  17. Selective hydrogenation of citral over supported Pt catalysts: insight into support effects

    Science.gov (United States)

    Wang, Xiaofeng; Hu, Weiming; Deng, Baolin; Liang, Xinhua

    2017-04-01

    Highly dispersed platinum (Pt) nanoparticles (NPs) were deposited on various substrates by atomic layer deposition (ALD) in a fluidized bed reactor at 300 °C. The substrates included multi-walled carbon nanotubes (MWCNTs), silica gel (SiO2), commercial γ-Al2O3, and ALD-prepared porous Al2O3 particles (ALD-Al2O3). The results of TEM analysis showed that 1.3 nm Pt NPs were highly dispersed on all different supports. All catalysts were used for the reaction of selective hydrogenation of citral to unsaturated alcohols (UA), geraniol, and nerol. Both the structure and acidity of supports affected the activity and selectivity of Pt catalysts. Pt/SiO2 showed the highest activity due to the strong acidity of SiO2 and the conversion of citral reached 82% after 12 h with a selectivity of 58% of UA. Pt/MWCNTs showed the highest selectivity of UA, which reached 65% with a conversion of 38% due to its unique structure and electronic effect. The cycling experiments indicated that Pt/MWCNTs and Pt/ALD-Al2O3 catalysts were more stable than Pt/SiO2, as a result of the different interactions between the Pt NPs and the supports.

  18. Selective hydrogenation of citral over supported Pt catalysts: insight into support effects

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiaofeng [Missouri University of Science and Technology, Department of Chemical and Biochemical Engineering (United States); Hu, Weiming; Deng, Baolin [University of Missouri, Department of Civil and Environmental Engineering (United States); Liang, Xinhua, E-mail: liangxin@mst.edu [Missouri University of Science and Technology, Department of Chemical and Biochemical Engineering (United States)

    2017-04-15

    Highly dispersed platinum (Pt) nanoparticles (NPs) were deposited on various substrates by atomic layer deposition (ALD) in a fluidized bed reactor at 300 °C. The substrates included multi-walled carbon nanotubes (MWCNTs), silica gel (SiO{sub 2}), commercial γ-Al{sub 2}O{sub 3}, and ALD-prepared porous Al{sub 2}O{sub 3} particles (ALD-Al{sub 2}O{sub 3}). The results of TEM analysis showed that ~1.3 nm Pt NPs were highly dispersed on all different supports. All catalysts were used for the reaction of selective hydrogenation of citral to unsaturated alcohols (UA), geraniol, and nerol. Both the structure and acidity of supports affected the activity and selectivity of Pt catalysts. Pt/SiO{sub 2} showed the highest activity due to the strong acidity of SiO{sub 2} and the conversion of citral reached 82% after 12 h with a selectivity of 58% of UA. Pt/MWCNTs showed the highest selectivity of UA, which reached 65% with a conversion of 38% due to its unique structure and electronic effect. The cycling experiments indicated that Pt/MWCNTs and Pt/ALD-Al{sub 2}O{sub 3} catalysts were more stable than Pt/SiO{sub 2}, as a result of the different interactions between the Pt NPs and the supports.

  19. Hysteresis Phenomena in Sulfur Dioxide Oxidation over Supported Vanadium Catalysts

    DEFF Research Database (Denmark)

    Masters, Stephen G.; Eriksen, Kim Michael; Fehrmann, Rasmus

    1997-01-01

    Catalyst deactivation and hysteresis behavior in industrial SO2-oxidation catalysts have been studied in the temperature region 350-480 C by combined in situ EPR spectroscopy and catalytic activity measurements. The feed gas composition simulated sulfuric acid synthesis gas and wet/dry de...

  20. Efficient alkyne homocoupling catalysed by copper immobilized on functionalized silica

    NARCIS (Netherlands)

    van Gelderen, L.; Rothenberg, G.; Calderone, V.R.; Wilson, K.; Shiju, N.R.

    2013-01-01

    Copper immobilized on a functionalized silica support is a good catalyst for the homocoupling of terminal alkynes. The so-called Glaser-Hay coupling reaction can be run in air with catalytic amounts of base. The copper catalyst is active for multiple substituted alkynes, in both polar and non-polar

  1. Highly active carbon supported Pd cathode catalysts for direct formic acid fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Mikolajczuk-Zychora, A., E-mail: amikolajczuk@ichf.edu.pl [Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw (Poland); Borodzinski, A.; Kedzierzawski, P.; Mierzwa, B. [Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw (Poland); Mazurkiewicz-Pawlicka, M. [Faculty of Materials Science and Engineering, Warsaw University of Technology, Wołoska 141, 02-507 Warsaw (Poland); Faculty of Chemical and Process Engineering, Warsaw University of Technology, Warynskiego 1, Warsaw (Poland); Stobinski, L. [Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw (Poland); Faculty of Chemical and Process Engineering, Warsaw University of Technology, Warynskiego 1, Warsaw (Poland); Ciecierska, E. [Faculty of Materials Science and Engineering, Warsaw University of Technology, Wołoska 141, 02-507 Warsaw (Poland); Zimoch, A.; Opałło, M. [Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw (Poland)

    2016-12-01

    Highlights: • Palladium catalyst used on the cathode DFAFC is comparable to commercial platinum catalyst. • The treatment of carbon supports in nitric acid(V) increases the electrochemically available metal surface area and the catalytic activity in oxygen reduction reaction of catalysts. - Abstract: One of the drawbacks of low-temperature fuel cells is high price of platinum-based catalysts used for the electroreduction of oxygen at the cathode of the fuel cell. The aim of this work is to develop the palladium catalyst that will replace commonly used platinum cathode catalysts. A series of palladium catalysts for oxygen reduction reaction (ORR) were prepared and tested on the cathode of Direct Formic Acid Fuel Cell (DFAFC). Palladium nanoparticles were deposited on the carbon black (Vulcan) and on multiwall carbon nanotubes (MWCNTs) surface by reduction of palladium(II) acetate dissolved in ethanol. Hydrazine was used as a reducing agent. The effect of functionalization of the carbon supports on the catalysts physicochemical properties and the ORR catalytic activity on the cathode of DFAFC was studied. The supports were functionalized by treatment in nitric acid for 4 h at 80 °C. The structure of the prepared catalysts has been characterized by thermogravimetric analysis (TGA), X-ray diffraction (XRD), transmission electron microscope (TEM) and cyclic voltammetry (CV). Hydrophilicity of the catalytic layers was determined by measuring contact angles of water droplets. The performance of the prepared catalysts has been compared with that of the commercial 20 wt.% Pt/C (Premetek) catalyst. The maximum power density obtained for the best palladium catalyst, deposited on the surface of functionalized carbon black, is the same as that for the commercial Pt/C (Premetek). Palladium is cheaper than platinum, therefore the developed cathode catalyst is promising for future applications.

  2. High surface area graphite as alternative support for proton exchange membrane fuel cell catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira-Aparicio, P.; Folgado, M.A. [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), Avda. Complutense 22, E-28040 Madrid (Spain); Daza, L. [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), Avda. Complutense 22, E-28040 Madrid (Spain); Instituto de Catalisis y Petroleoquimica (CSIC), C/Marie Curie, 2 Campus de Cantoblanco, E-28049 Madrid (Spain)

    2009-07-01

    The suitability of a high surface area graphite (HSAG) as proton exchange membrane fuel cell (PEMFC) catalyst support has been evaluated and compared with that of the most popular carbon black: the Vulcan XC72. It has been observed that Pt is arranged on the graphite surface resulting in different structures which depend on the catalysts synthesis conditions. The influence that the metal particle size and the metal-support interaction exert on the catalysts degradation rate is analyzed. Temperature programmed oxidation (TPO) under oxygen containing streams has been shown to be a useful method to assess the resistance of PEMFC catalysts to carbon corrosion. The synthesized Pt/HSAG catalysts have been evaluated in single cell tests in the cathode catalytic layer. The obtained results show that HSAG can be a promising alternative to the traditionally used Vulcan XC72 carbon black when suitable catalysts synthesis conditions are used. (author)

  3. Highly active carbon supported Pd cathode catalysts for direct formic acid fuel cells

    Science.gov (United States)

    Mikolajczuk-Zychora, A.; Borodzinski, A.; Kedzierzawski, P.; Mierzwa, B.; Mazurkiewicz-Pawlicka, M.; Stobinski, L.; Ciecierska, E.; Zimoch, A.; Opałło, M.

    2016-12-01

    One of the drawbacks of low-temperature fuel cells is high price of platinum-based catalysts used for the electroreduction of oxygen at the cathode of the fuel cell. The aim of this work is to develop the palladium catalyst that will replace commonly used platinum cathode catalysts. A series of palladium catalysts for oxygen reduction reaction (ORR) were prepared and tested on the cathode of Direct Formic Acid Fuel Cell (DFAFC). Palladium nanoparticles were deposited on the carbon black (Vulcan) and on multiwall carbon nanotubes (MWCNTs) surface by reduction of palladium(II) acetate dissolved in ethanol. Hydrazine was used as a reducing agent. The effect of functionalization of the carbon supports on the catalysts physicochemical properties and the ORR catalytic activity on the cathode of DFAFC was studied. The supports were functionalized by treatment in nitric acid for 4 h at 80 °C. The structure of the prepared catalysts has been characterized by thermogravimetric analysis (TGA), X-ray diffraction (XRD), transmission electron microscope (TEM) and cyclic voltammetry (CV). Hydrophilicity of the catalytic layers was determined by measuring contact angles of water droplets. The performance of the prepared catalysts has been compared with that of the commercial 20 wt.% Pt/C (Premetek) catalyst. The maximum power density obtained for the best palladium catalyst, deposited on the surface of functionalized carbon black, is the same as that for the commercial Pt/C (Premetek). Palladium is cheaper than platinum, therefore the developed cathode catalyst is promising for future applications.

  4. Various conformations of carbon nanocoils prepared by supported Ni-Fe/molecular sieve catalyst.

    Science.gov (United States)

    Yang, Shaoming; Chen, Xiuqin; Takeuchi, K; Motojima, Seiji

    2006-01-01

    The carbon nanocoils with various kinds of conformations were prepared by the catalytic pyrolysis of acetylene using the Ni metal catalyst supported on molecular Sieves which was prepared using Fe-containing kaolin as the raw material. There are four kinds of carbon nanocoils conformations produced by this catalyst. The influences of reaction temperature and gas conditions on the conformations of the nanocoils were investigated and the reasons of forming nano-size coils were discussed by comparison with pure Ni metal catalyst.

  5. The black rock series supported SCR catalyst for NOxremoval.

    Science.gov (United States)

    Xie, Bin; Luo, Hang; Tang, Qing; Du, Jun; Liu, Zuohua; Tao, Changyuan

    2017-09-01

    Black rock series (BRS) is of great potential for their plenty of valued oxides which include vanadium, iron, alumina and silica oxides, etc. BRS was used for directly preparing of selective catalytic reduction (SCR) catalyst by modifying its surface texture with SiO 2 -TiO 2 sols and regulating its catalytic active constituents with V 2 O 5 and MoO 3 . Consequently, 90% NO removal ratio was obtained within 300-400 °C over the BRS-based catalyst. The structure and properties of the BRS-based catalyst were characterized by the techniques of N 2 adsorption-desorption, X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), H 2 -temperature programmed reduction (H 2 -TPR), and NH 3 -temperature programmed desorption (NH 3 -TPD). The results revealed that the BRS-based catalyst possesses favorable properties for NO x removal, including highly dispersed active components, abundant surface-adsorbed oxygen O α , well redox property, and numerous Brønsted acid sites. Particularly, the BRS-based catalyst exhibited considerable anti-poisoning performance compared with commercial TiO 2 -based catalyst. The former catalyst shows a NO conversion surpassing 80% from 300 to 400 °C for potassium poisoning, and a durability of SO 2 and H 2 O exceeding 85% at temperatures from 300 to 450 °C.

  6. Graphene-Supported Platinum Catalyst-Based Membrane Electrode Assembly for PEM Fuel Cell

    Science.gov (United States)

    Devrim, Yilser; Albostan, Ayhan

    2016-08-01

    The aim of this study is the preparation and characterization of a graphene-supported platinum (Pt) catalyst for proton exchange membrane fuel cell (PEMFC) applications. The graphene-supported Pt catalysts were prepared by chemical reduction of graphene and chloroplatinic acid (H2PtCl6) in ethylene glycol. X-ray powder diffraction, thermogravimetric analysis (TGA) and scanning electron microscopy have been used to analyze structure and surface morphology of the graphene-supported catalyst. The TGA results showed that the Pt loading of the graphene-supported catalyst was 31%. The proof of the Pt particles on the support surfaces was also verified by energy-dispersive x-ray spectroscopy analysis. The commercial carbon-supported catalyst and prepared Pt/graphene catalysts were used as both anode and cathode electrodes for PEMFC at ambient pressure and 70°C. The maximum power density was obtained for the Pt/graphene-based membrane electrode assembly (MEA) with H2/O2 reactant gases as 0.925 W cm2. The maximum current density of the Pt/graphene-based MEA can reach 1.267 and 0.43 A/cm2 at 0.6 V with H2/O2 and H2/air, respectively. The MEA prepared by the Pt/graphene catalyst shows good stability in long-term PEMFC durability tests. The PEMFC cell voltage was maintained at 0.6 V without apparent voltage drop when operated at 0.43 A/cm2 constant current density and 70°C for 400 h. As a result, PEMFC performance was found to be superlative for the graphene-supported Pt catalyst compared with the Pt/C commercial catalyst. The results indicate the graphene-supported Pt catalyst could be utilized as the electrocatalyst for PEMFC applications.

  7. Nitrogen-doped carbon-supported cobalt-iron oxygen reduction catalyst

    Science.gov (United States)

    Zelenay, Piotr; Wu, Gang

    2014-04-29

    A Fe--Co hybrid catalyst for oxygen reaction reduction was prepared by a two part process. The first part involves reacting an ethyleneamine with a cobalt-containing precursor to form a cobalt-containing complex, combining the cobalt-containing complex with an electroconductive carbon supporting material, heating the cobalt-containing complex and carbon supporting material under conditions suitable to convert the cobalt-containing complex and carbon supporting material into a cobalt-containing catalyst support. The second part of the process involves polymerizing an aniline in the presence of said cobalt-containing catalyst support and an iron-containing compound under conditions suitable to form a supported, cobalt-containing, iron-bound polyaniline species, and subjecting said supported, cobalt-containing, iron bound polyaniline species to conditions suitable for producing a Fe--Co hybrid catalyst.

  8. Effect of the dispersants on Pd species and catalytic activity of supported palladium catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Yue [Key Laboratory for Green Chemical Process of Ministry of Education, School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan 430205 (China); Yang, Xiaojun, E-mail: 10100201@wit.edu.cn [Key Laboratory for Green Chemical Process of Ministry of Education, School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan 430205 (China); Cao, Shuo, E-mail: cao23@email.sc.edu [North America R& D Center, Clariant BU Catalysts, Louisville, 40209, KY (United States); Zhou, Jie [Key Laboratory for Green Chemical Process of Ministry of Education, School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan 430205 (China); Wu, Yuanxin [Key Laboratory for Green Chemical Process of Ministry of Education, School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan 430205 (China); School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); Han, Jinyu [School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); Yan, Zhiguo [Key Laboratory for Green Chemical Process of Ministry of Education, School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan 430205 (China); Zheng, Mingming [Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Hubei Key Laboratory of Oilcrops Lipid Chemistry and Nutrition, Wuhan 430062 (China)

    2017-04-01

    Highlights: • Polyvinyl alcohol (PVA) inhibited the sintering and reduction of Pd nanoparticles. • Activity was improved for supported Pd catalysts with PVA modified method. • PVA modified method minimized the catalyst deactivation. • This work provides an insight of the regeneration strategies for Pd catalysts. - Abstract: A series of supported palladium catalysts has been prepared through the precipitation method and the reduction method, using polyvinyl alcohol (PVA) and polyvinylpyrrolidone (PVP) as dispersants. The effects of the dispersants on the properties of catalysts were evaluated and the catalytic performance of the new materials was investigated for the oxidative carbonylation of phenol to diphenyl carbonate (DPC). The catalysts as prepared were also characterized by the X-ray diffraction (XRD), transmission electron microscope (TEM), Brunner-Emmet-Teller (BET) measurements and X-ray photoelectron spectroscopy (XPS) techniques. The results show that the addition of the dispersants had no effect on the crystal phase of the catalysts. However, the dispersion of Pd particles was improved when the dispersants were used. Moreover, the particle sizes of Pd nanoparticles modified by PVA were smaller than those modified by PVP. The catalysts prepared using the dispersants gave better yields of DPC than the catalysts prepared without the dispersants. The highest yield of DPC was 17.9% with the PVA-Red catalyst. The characterization results for the used catalysts showed that the Pd species in the PVA-Red catalyst remained mostly divalent and the lattice oxygen species were consumed during the reaction, which could lead to the higher catalytic activity of the PVA-Red catalyst. The experimental results confirm that PVA effectively inhibited the sintering and reduction of active Pd species in the oxidative carbonylation of phenol.

  9. Green and selective synthesis of N-substituted amides using water soluble porphyrazinato copper(II) catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Ghodsinia, Sara S.E.; Akhlaghinia, Batool; Eshghi, Hossein, E-mail: akhlaghinia@um.ac.ir [Ferdowsi University of Mashhad (Iran, Islamic Republic of). Faculty of Sciences. Department of Chemistry; Safaei, Elham [Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan (Iran, Islamic Republic of). Department of Chemistry

    2013-06-15

    N, N',N{sup ,} N{sup '}-Tetramethyl tetra-2,3-pyridinoporphyrazinato copper(II) methyl sulfate ([Cu(2,3-tmtppa)](MeSO{sub 4}){sub 4}) efficiently catalyzed the direct conversion of nitriles to N-substituted amides. The one pot selective synthesis of the N-substituted amides from nitriles and primary amines was performed in refluxing H{sub 2}O. The catalyst was recovered and reused at least four times, maintaining its efficiency. (author)

  10. Synthesis of the catalyst

    Indian Academy of Sciences (India)

    Admin

    50 585; Duan Y C, Ma Y C, Zhang E, Shi X J, Wang M M, Ye X W and Liu H M 2013 Design and synthesis of novel 1,2,3-triazole-dithiocarbamate hybrids as ... M, Minato T, Bao M and Yamamoto Y 2011 Nanoporous Copper Metal Catalyst in Click Chemistry: Nanoporosity-Dependent Activity without Supports and Bases; ...

  11. Activated Carbon-Supported Tetrapropylammonium Perruthenate Catalysts for Acetylene Hydrochlorination

    Directory of Open Access Journals (Sweden)

    Xing Li

    2017-10-01

    Full Text Available The Ru-based catalysts, including Ru/AC (activated carbon, TPAP (tetrapropylammonium perruthenate/AC, TPAP/AC-HNO3, and TPAP/AC-HCl, were prepared and assessed for the direct synthesis of vinyl chloride monomer. The results indicate that the TPAP/AC-HCl catalyst exhibits the best performance with the conversion falling from 97% to 91% in 48 hours’ reaction under the conditions of 180 °C, a GHSV(C2H2 of 180 h−1, and the feed ratio VHCl/VC2H2 of 1.15. The substitution of RuCl3 precursor with high valent TPAP species leads to more ruthenium oxides active species in the catalysts; the acidification treatment of carrier in TPAP/AC catalyst can produce an enhanced interaction between the active species and the modified functional groups on the carrier, and it is beneficial to inhibit the carbon deposition and sintering of ruthenium species in the reaction process, greatly increase the adsorption ability of reactants, and further increase the amount of dominating active species in the catalysts, thus improving the catalytic performance. This also provides a promising strategy to explore high efficient and economic mercury-free catalysts for the hydrochlorination of acetylene.

  12. Potassium hydroxide catalyst supported on palm shell activated carbon for transesterification of palm oil

    Energy Technology Data Exchange (ETDEWEB)

    Baroutian, Saeid; Aroua, Mohamed Kheireddine; Raman, Abdul Aziz Abdul; Sulaiman, Nik Meriam Nik [Department of Chemical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia)

    2010-11-15

    In this study, potassium hydroxide catalyst supported on palm shell activated carbon was developed for transesterification of palm oil. The Central Composite Design (CCD) of the Response Surface Methodology (RSM) was employed to investigate the effects of reaction temperature, catalyst loading and methanol to oil molar ratio on the production of biodiesel using activated carbon supported catalyst. The highest yield was obtained at 64.1 C reaction temperature, 30.3 wt.% catalyst loading and 24:1 methanol to oil molar ratio. The physical and chemical properties of the produced biodiesel met the standard specifications. This study proves that activated carbon supported potassium hydroxide is an effective catalyst for transesterification of palm oil. (author)

  13. The Effect of Cobalt Loading on Fischer Tropsch Synthesis Over Silicon Carbide Supported Catalyst.

    Science.gov (United States)

    Lee, Jae Suk; Jung, Jae Sun; Moon, Dong Ju

    2015-01-01

    A series of Co (5-30 wt%) based SiC supported catalysts were prepared by impregnation method and investigated for FTS reaction. The FTS reaction was carried out in a fixed bed reactor system with the H2/CO molar ratio of 2, reaction temperature of 230 degrees C and reaction pressure of 20 bar for 120 h. All catalysts were characterized by N2 physisorption, XRD, TPR, SEM and TEM techniques. It was found that 15 wt% Co/SiC catalyst showed better catalytic performance with high selectivity of C(5+) hydrocarbons than the other catalysts. The results, suggest that the catalytic performance of the catalysts depends on average pore size of support and surface density of cobalt, metal and support interactions.

  14. Magnetic silica supported palladium catalyst: synthesis of allyl aryl ethers in water

    Science.gov (United States)

    A simple and benign procedure for the synthesis of aryl allyl ethers has been developed using phenols, allyl acetates and magnetically recyclable silica supported palladium catalyst in water; performance of reaction in air and easy separation of the catalyst using an external mag...

  15. Cobalt supported on carbon nanofibers as catalysts for the Fischer-Tropsch synthesis

    NARCIS (Netherlands)

    Bezemer, G.L.

    2006-01-01

    The Fischer-Tropsch (FT) process converts synthesis gas (H2/CO) over a heterogeneous catalyst into hydrocarbons. Generally, cobalt catalysts supported on oxidic carriers are used for the FT process, however it appears to be difficult to obtain and maintain fully reduced cobalt particles. To overcome

  16. Metathesis of cardanol over ammonium tagged Hoveyda-Grubbs type catalyst supported on SBA-15

    Czech Academy of Sciences Publication Activity Database

    Balcar, Hynek; Žilková, Naděžda; Kubů, Martin; Polášek, Miroslav; Zedník, J.

    2017-01-01

    Roč. 304, APR 2018 (2017), s. 127-134 ISSN 0920-5861 R&D Projects: GA ČR GA17-01440S Institutional support: RVO:61388955 Keywords : Cardanol * Flow chemistry * Hoveyda-Grubbs type catalyst * Immobilized catalyst Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 4.636, year: 2016

  17. Hydrogen from ethylene glycol by supercritical water reforming supported noble and base metal catalysts

    NARCIS (Netherlands)

    de Vlieger, Dennis; Chakinala, A.G.; Lefferts, Leonardus; Kersten, Sascha R.A.; Seshan, Kulathuiyer; Brilman, Derk Willem Frederik

    2012-01-01

    Catalytic reforming of ethylene glycol (5 and 15 wt%) in supercritical water (450 °C and 250 bar) in the presence of alumina supported mono- and bi-metallic catalysts based on Ir, Pt and Ni was studied. Pt catalyst showed the highest hydrogen yields compared to Ir and Ni. Varying the Pt loading

  18. Catalytic combustion of trichloroethylene over TiO2-SiO2 supported catalysts

    NARCIS (Netherlands)

    Kulazynski, M.; van Ommen, J.G.; Trawczynski, J.; Walendziewski, J.

    2002-01-01

    Combustion of trichloroethylene (TCE) on Cr2O3, V2O5, Pt or Pd catalysts supported on TiO2-SiO2 as a carrier has been investigated. It was found that oxide catalysts are very active but their activity quickly diminishes due to loss of the active component, especially at higher reaction temperatures

  19. Preparation and Application of Carbon-Nanofiber Based Microstructured Materials as Catalyst Supports.

    NARCIS (Netherlands)

    Chinthaginjala, J.K.; Seshan, Kulathuiyer; Lefferts, Leonardus

    2007-01-01

    In the application of heterogeneous catalysts in liquid phase reactions, the rate of reaction as well as selectivity is often negatively influenced by mass transfer limitations in the stagnant liquid in the pores of the catalyst support. Internal mass transfer limitations can be reduced by

  20. Effect of plasma treatments to graphite nanofibers supports on electrochemical behaviors of metal catalyst electrodes.

    Science.gov (United States)

    Lee, Hochun; Jung, Yongju; Kim, Seok

    2012-02-01

    In the present work, we had studied the graphite nanofibers as catalyst supports after a plasma treatment for studying the effect of surface modification. By controlling the plasma intensity, a surface functional group concentration was changed. The nanoparticle size, loading efficiency, and catalytic activity were studied, after Pt-Ru deposition by a chemical reduction. Pt-Ru catalysts deposited on the plasma-treated GNFs showed the smaller size, 3.58 nm than the pristine GNFs. The catalyst loading contents were enhanced with plasma power and duration time increase, meaning an enhanced catalyst deposition efficiency. Accordingly, cyclic voltammetry result showed that the specific current density was increased proportionally till 200 W and then the value was decreased. Enhanced activity of 40 (mA mg(-1)-catalyst) was accomplished at 200 W and 180 sec duration time. Consequently, it was found that the improved electroactivity was originated from the change of size or morphology of catalysts by controlling the plasma intensity.

  1. Growth Mechanism of Single-Walled Carbon Nanotubes on Iron–Copper Catalyst and Chirality Studies by Electron Diffraction

    DEFF Research Database (Denmark)

    He, Maoshuai; Liu, Bilu; Chernov, Alexander I.

    2012-01-01

    Chiralities of single-walled carbon nanotubes grown on an atomic layer deposition prepared bimetallic FeCu/MgO catalyst were evaluated quantitatively using nanobeam electron diffraction. The results reveal that the growth yields nearly 90% semiconducting tubes, 45% of which are of the (6,5) type....... The growth mechanisms as well as the roles of different components in the catalyst were studied in situ using environmental transmission electron microscopy and infrared spectroscopy. On the basis of the understanding of carbon nanotube growth mechanisms, an MgO-supported FeCu catalyst was prepared...... by impregnation, showing similar catalytic performance as the atomic layer deposition-prepared catalyst, yielding single-walled carbon nanotubes with a similar narrow chirality distribution....

  2. Hydrogenation of CO2 to methanol using copper/zinc oxide-based catalyst: Effect of active metal ratio

    Science.gov (United States)

    Zabidi, Noor Asmawati Mohd; Tasfy, Sara; Shaharun, Maizatul Shima

    2016-11-01

    Effects of Cu:Zn ratio on the catalytic performance of synthesized SBA-15 supported Cu/ZnO-based (CZS) catalyst for the hydrogenation of CO2 to methanol was investigated in a fixed bed reactor. The physicochemical properties of the synthesized CZS catalyst in terms of textural properties, morphological and reducibility are presented. Methanol productivity was found to be influenced by the ratio of Cu and Zn in the catalyst formulation. Methanol selectivity of 92.1 % and CO2 conversion of 14.2 % was achieved over CZS catalyst with active metal ratio of 70 %Cu:30% Zn in CO2 hydrogenation reaction performed at 250°C, 2.25 MPa, and H2/CO2 ratio of 3.

  3. Characterization and Catalytic Activity for the Oxidation of Ethane and Propane on Platinum and Copper Supported on CeO2/Al2O3

    Directory of Open Access Journals (Sweden)

    Cataluña R.

    1998-01-01

    Full Text Available Ethane and propane oxidation on platinum and copper supported on Al2O3 and CeO2/Al2O3 catalysts were studied comparatively by examining reaction rates as a function of temperature. Results show that the addition of cerium oxide shifts the catalytic activity to higher temperatures. This negative influence is less pronounced in the case of supported copper samples, which on the basis of EPR and FTIR of adsorbed CO results is attributed to the low relative amount of this metal is in contact with ceria. The decrease in activity the presence of ceria might be due to changes in metal particle size or to the stabilization of the oxidized states of the metals, induced by their interactions with cerium oxide. The higher activity of platinum, in comparison with copper, is attributed to its higher reducibility along with an easier hydrocarbon activation on that metal.

  4. Low-temperature carbon monoxide oxidation over zirconia-supported CuO–CeO{sub 2} catalysts: Effect of zirconia support properties

    Energy Technology Data Exchange (ETDEWEB)

    Moretti, Elisa, E-mail: elisa.moretti@unive.it [Dipartimento di Scienze Molecolari e Nanosistemi, Università Ca' Foscari Venezia, INSTM Venice Research Unit, Via Torino 155/B, 30172 Mestre Venezia (Italy); Molina, Antonia Infantes [Departamento de Química Inorgánica, Cristalografía y Mineralogía, Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos, 29071 Málaga (Spain); Sponchia, Gabriele; Talon, Aldo; Frattini, Romana [Dipartimento di Scienze Molecolari e Nanosistemi, Università Ca' Foscari Venezia, INSTM Venice Research Unit, Via Torino 155/B, 30172 Mestre Venezia (Italy); Rodriguez-Castellon, Enrique [Departamento de Química Inorgánica, Cristalografía y Mineralogía, Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos, 29071 Málaga (Spain); Storaro, Loretta [Dipartimento di Scienze Molecolari e Nanosistemi, Università Ca' Foscari Venezia, INSTM Venice Research Unit, Via Torino 155/B, 30172 Mestre Venezia (Italy)

    2017-05-01

    Highlights: • CuO-CeO{sub 2}/ZrO{sub 2} materials were investigated in the low temperature CO oxidation. • High surface area ZrO{sub 2} synthetized by sol-gel method. • Low ZrO{sub 2} surface area synthetized by fast precipitation. • Sol-gel samples showed, after impregnation, a severe decrease of surface area. • CuO-CeO{sub 2}/ZrO{sub 2} with precipitated ZrO{sub 2} led to a very active catalyst. - Abstract: A study was conducted to investigate the effect of the preparation route of ZrO{sub 2} in CuO–CeO{sub 2}/ZrO{sub 2} catalysts for the oxidation of carbon monoxide at low temperature (COX). Four ZrO{sub 2} supports were synthetized via either type sol-gel methodology or precipitation. The final Cu-Ce-Zr oxide catalysts were prepared by incipient wetness co-impregnation with copper and cerium solutions (with a loading of 6 wt% of CuO and 20 wt% of CeO{sub 2}). The catalyst crystalline phases, texture and active species reducibility were determined by XRD, N{sub 2} physisorption at −196 °C and H{sub 2}-TPR, respectively; meanwhile the surface composition and copper-cerium electronic states were studied by XPS. The catalytic activity was evaluated in the oxidation of CO to CO{sub 2}, in the 40–215 °C temperature range. Catalytic results evidenced that the samples prepared by a sol-gel methodology showed, after the impregnation, a severe decrease of specific surface area and pore volume attributable to a wide degree of pore blockage caused by the presence of metal oxide particles and a collapse of the structure partially burying the active sites. A simple co-impregnation of a zirconia support, obtained through facile and fast precipitation, provided instead a catalyst with very good redox properties and high dispersion of the active phases, which completely oxidizes CO in the range 115–215 °C with T{sub 50} of 65 °C. This higher observed activity was ascribed to the formation of a larger fraction of highly dispersed and easily reducible Cu

  5. Supported Catalysts for CO2 Methanation: A Review

    Directory of Open Access Journals (Sweden)

    Patrizia Frontera

    2017-02-01

    Full Text Available CO2 methanation is a well-known reaction that is of interest as a capture and storage (CCS process and as a renewable energy storage system based on a power-to-gas conversion process by substitute or synthetic natural gas (SNG production. Integrating water electrolysis and CO2 methanation is a highly effective way to store energy produced by renewables sources. The conversion of electricity into methane takes place via two steps: hydrogen is produced by electrolysis and converted to methane by CO2 methanation. The effectiveness and efficiency of power-to-gas plants strongly depend on the CO2 methanation process. For this reason, research on CO2 methanation has intensified over the last 10 years. The rise of active, selective, and stable catalysts is the core of the CO2 methanation process. Novel, heterogeneous catalysts have been tested and tuned such that the CO2 methanation process increases their productivity. The present work aims to give a critical overview of CO2 methanation catalyst production and research carried out in the last 50 years. The fundamentals of reaction mechanism, catalyst deactivation, and catalyst promoters, as well as a discussion of current and future developments in CO2 methanation, are also included.

  6. Synthesis and comparison of the activities of a catalyst supported on two silicate materials

    Energy Technology Data Exchange (ETDEWEB)

    Vieira, Eduardo G., E-mail: eduardogv5007@gmail.com [Departamento de Física e Química, Unesp-Univ Estadual Paulista, Av. Brasil, 56-Centro, Caixa Postal 31, CEP 15385-000, Ilha Solteira, São Paulo (Brazil); Silva, Rafael O.; Carmo, Devaney R. do [Departamento de Física e Química, Unesp-Univ Estadual Paulista, Av. Brasil, 56-Centro, Caixa Postal 31, CEP 15385-000, Ilha Solteira, São Paulo (Brazil); Junior, Enes F. [Departamento de Fitotecnia, Tecnologia de Alimentos e Sócio Economia, Faculdade de Engenharia de Ilha Solteira, Universidade Estadual Paulista, Ilha Solteira, São Paulo (Brazil); Dias Filho, Newton L., E-mail: nldias@unesc.net [Departamento de Física e Química, Unesp-Univ Estadual Paulista, Av. Brasil, 56-Centro, Caixa Postal 31, CEP 15385-000, Ilha Solteira, São Paulo (Brazil); Universidade do Extremo Sul Catarinense, Av. Universitaria, 1105, CP 3167, CEP 88806-000, Criciúma, SC (Brazil)

    2017-04-15

    The focus of this work is inspecting the synthesis and comparison of the activities of a catalyst supported on two silicate materials in the epoxidation of 1-octene. The two new catalyst materials were characterized by infrared spectroscopy, elemental analysis, solid-state {sup 29}Si and {sup 13}C nuclear magnetic resonance, scanning electronic microscope (SEM) and analysis of nitrogen. Lastly, the two new catalysts, Silsesq-TCA-[(W(CO){sub 3}I{sub 2}){sub 3}] and Silica-TCA-[W(CO){sub 3}I{sub 2}] were tested as catalysts in reactions of epoxidation of 1-octene and compared with their analogue not supported [W(CO){sub 3}I{sub 2}(thiocarbamide)]. After an extensive literature search, we verified that our work is the first that has reported the immobilization process of [W(CO){sub 3}I{sub 2}(NCCH{sub 3}){sub 2}] on silsesquioxane and silica gel functionalized with propyl-thiocarbamide groups and their applications as catalysts of reactions of catalytic epoxidation of 1-octene. - Highlights: • Immobilization of [W(CO){sub 3}I{sub 2}(NCCH{sub 3}){sub 2}] complex onto mesoporous supports. • Synthesis and characterization of new mesoporous catalysts. • The new catalysts exhibit great catalytic activity in the epoxidation of 1-octene. • Recyclable catalysts with excellent reusability and stability.

  7. Platinum supported catalysts for carbon monoxide preferential oxidation: Study of support influence

    Energy Technology Data Exchange (ETDEWEB)

    Padilla, R.; Rodriguez, L.; Serrano-Lotina, A.; Daza, L. [Instituto de Catalisis y Petroleoquimica (CSIC), C/Marie Curie 2, Campus Cantoblanco, 28049 Madrid (Spain); Benito, M. [Instituto de Catalisis y Petroleoquimica (CSIC), C/Marie Curie 2, Campus Cantoblanco, 28049 Madrid (Spain); Centro de Investigaciones Energeticas Medioambientales y Tecnologicas (CIEMAT), Av. Complutense 22, 28040 Madrid (Spain)

    2009-07-01

    The aim of this work is to study the influence of the addition of different oxides to an alumina support, on surface acidity and platinum reducibility in platinum-based catalysts, as well as their effect on the activity and selectivity in CO preferential oxidation, in presence of hydrogen. A correlation between surface acidity and acid strength of surface sites and metal reducibility was obtained, being Pt-support interaction a function of the acid sites concentration under a particular temperature range. In platinum supported on alumina catalysts, CO oxidation follows a Langmuir-Hinshelwood mechanism, where O{sub 2} and CO compete in the adsorption on the same type of active sites. It is noteworthy that the addition of La{sub 2}O{sub 3} modifies the reaction mechanism. In this case, CO is not only adsorbed on the Pt active sites but also on La{sub 2}O{sub 3}, forming bridge bonded carbonates which leads to high reactivity at low temperatures. An increase on temperature produces CO desorption from Pt surface sites and favours oxygen adsorption producing CO{sub 2}. CO oxidation with surface hydroxyl groups was activated producing simultaneously CO{sub 2} and H{sub 2}. (author)

  8. Impact of lignin structure on oil production via hydroprocessing with a copper-doped porous metal oxide catalyst.

    Science.gov (United States)

    Gillet, Sebastien; Petitjean, Laurene; Aguedo, Mario; Lam, Chun-Ho; Blecker, Christophe; Anastas, Paul T

    2017-06-01

    A copper-catalyzed depolymerization strategy was employed to investigate the impact of lignin structure on the distribution of hydroprocessing products. Specifically, lignin was extracted from beech wood and miscanthus grass. The extracted lignins, as well as a commercial lignin (P1000), were then fractionated using ethyl acetate to provide three different portions for each source of lignin [total of 9 fractions]. Each fraction was structurally characterized and treated with a copper-doped porous metal oxide (Cu-PMO) catalyst under 4MPa H2 and at 180°C for 12h. The reaction conditions provided notable yields of oil for each fraction of lignin. Analysis of the oils indicated phenolic monomers of commercial interest. The structure of these monomers and the yield of monomer-containing oil was dependent on the origin of the lignin. Our results indicate that hydroprocessing with a Cu-PMO catalyst can selectively provide monomers of commercial interest by careful choice of lignin starting material. Copyright © 2017. Published by Elsevier Ltd.

  9. Laser Synthesis of Supported Catalysts for Carbon Nanotubes

    Science.gov (United States)

    VanderWal, Randall L.; Ticich, Thomas M.; Sherry, Leif J.; Hall, Lee J.; Schubert, Kathy (Technical Monitor)

    2003-01-01

    Four methods of laser assisted catalyst generation for carbon nanotube (CNT) synthesis have been tested. These include pulsed laser transfer (PLT), photolytic deposition (PLD), photothermal deposition (PTD) and laser ablation deposition (LABD). Results from each method are compared based on CNT yield, morphology and structure. Under the conditions tested, the PLT was the easiest method to implement, required the least time and also yielded the best pattemation. The photolytic and photothermal methods required organometallics, extended processing time and partial vacuums. The latter two requirements also held for the ablation deposition approach. In addition to control of the substrate position, controlled deposition duration was necessary to achieve an active catalyst layer. Although all methods were tested on both metal and quartz substrates, only the quartz substrates proved to be inactive towards the deposited catalyst particles.

  10. Effects of copper-precursors on the catalytic activity of Cu/graphene catalysts for the selective catalytic oxidation of ammonia

    Science.gov (United States)

    Li, Jingying; Tang, Xiaolong; Yi, Honghong; Yu, Qingjun; Gao, Fengyu; Zhang, Runcao; Li, Chenlu; Chu, Chao

    2017-08-01

    Different copper-precursors were used to prepare Cu/graphene catalysts by an impregnation method. XRD, Raman spectra, TEM, BET, XPS, H2-TPR, NH3-TPD, DRIFTS and catalytic activity test were used to characterize and study the effect of precursors on the catalytic activity of Cu/graphene catalysts for NH3-SCO reaction. The large specific surface area of Cu/graphene catalysts and high dispersion of the metal particles on the graphene caused the well catalytic activity of NH3-SCO reaction. Compared to Cu/GE(AC), Cu/GE(N) showed better catalytic performance, and the complete NH3 removal efficiency was obtained at 250 °C with N2 selectivity of 85%. The copper-precursors had influence on the distribution of surface Cu species and further affected the catalytic activity of Cu/GE catalysts. The more amount of surface Cu species and highly dispersed CuO particles on the graphene surface formed by using copper nitrate as precursor could significantly improve the reducibility of catalysts and enhance NH3 adsorption, thereby improving the catalytic activity of Cu/graphene catalyst.

  11. Steam Reforming of Acetic Acid over Co-Supported Catalysts: Coupling Ketonization for Greater Stability

    Energy Technology Data Exchange (ETDEWEB)

    Davidson, Stephen D. [Energy and Environmental; Spies, Kurt A. [Energy and Environmental; Mei, Donghai [Energy and Environmental; Kovarik, Libor [Energy and Environmental; Kutnyakov, Igor [Energy and Environmental; Li, Xiaohong S. [Energy and Environmental; Lebarbier Dagle, Vanessa [Energy and Environmental; Albrecht, Karl O. [Energy and Environmental; Dagle, Robert A. [Energy and Environmental

    2017-09-11

    We report on the markedly improved stability of a novel 2-bed catalytic system, as compared to a conventional 1-bed steam reforming catalyst, for the production of H2 from acetic acid. The 2-bed catalytic system comprises of i) a basic oxide ketonization catalyst for the conversion of acetic acid to acetone, and a ii) Co-based steam reforming catalyst, both catalytic beds placed in sequence within the same unit operation. Steam reforming catalysts are particularly prone to catalytic deactivation when steam reforming acetic acid, used here as a model compound for the aqueous fraction of bio-oil. Catalysts comprising MgAl2O4, ZnO, CeO2, and activated carbon (AC) both with and without Co-addition were evaluated for conversion of acetic acid and acetone, its ketonization product, in the presence of steam. It was found that over the bare oxide support only ketonization activity was observed and coke deposition was minimal. With addition of Co to the oxide support steam reforming activity was facilitated and coke deposition was significantly increased. Acetone steam reforming over the same Co-supported catalysts demonstrated more stable performance and with less coke deposition than with acetic acid feedstock. DFT analysis suggests that over Co surface CHxCOO species are more favorably formed from acetic acid versus acetone. These CHxCOO species are strongly bound to the Co catalyst surface and could explain the higher propensity for coke formation from acetic acid. Based on these findings, in order to enhance stability of the steam reforming catalyst a dual-bed (2-bed) catalyst system was implemented. Comparing the 2-bed and 1-bed (Co-supported catalyst only) systems under otherwise identical reaction conditions the 2-bed demonstrated significantly improved stability and coke deposition was decreased by a factor of 4.

  12. Life Support Catalyst Regeneration Using Ionic Liquids and In Situ Resources

    Science.gov (United States)

    Abney, Morgan B.; Karr, Laurel J.; Paley, Mark S.; Donovan, David N.; Kramer, Teersa J.

    2016-01-01

    Oxygen recovery from metabolic carbon dioxide is an enabling capability for long-duration manned space flight. Complete recovery of oxygen (100%) involves the production of solid carbon. Catalytic approaches for this purpose, such as Bosch technology, have been limited in trade analyses due in part to the mass penalty for high catalyst resupply caused by carbon fouling of the iron or nickel catalyst. In an effort to mitigate this challenge, several technology approaches have been proposed. These approaches have included methods to prolong the life of the catalysts by increasing the total carbon mass loading per mass catalyst, methods for simplified catalyst introduction and removal to limit the resupply container mass, methods of using in situ resources, and methods to regenerate catalyst material. Research and development into these methods is ongoing, but only use of in situ resources and/or complete regeneration of catalyst material has the potential to entirely eliminate the need for resupply. The use of ionic liquids provides an opportunity to combine these methods in a technology approach designed to eliminate the need for resupply of oxygen recovery catalyst. Here we describe the results of an initial feasibility study using ionic liquids and in situ resources for life support catalyst regeneration, we discuss the key challenges with the approach, and we propose future efforts to advance the technology.

  13. Ni catalysts with different promoters supported on zeolite for dry reforming of methane

    KAUST Repository

    Alotaibi, Raja

    2015-07-08

    Dry reforming of methane (DRM) is considered a high endothermic reaction with operating temperatures between 700 and 1000 °C to achieve high equilibrium conversion of CH4 and CO2 to the syngas (H2 and CO). The conventional catalysts used for DRM are Ni-based catalysts. However, many of these catalysts suffer from the short longevity due to carbon deposition. This study aims to evaluate the effect of La and Ca as promoters for Ni-based catalysts supported on two different zeolite supports, ZL (A) (BET surface area = 925 m2/g, SiO2/Al2O3 mol ratio = 5.1), and ZL (B) (BET surface area = 730 m2/g, SiO2/Al2O3 mol ratio = 12), for DRM. The physicochemical properties of the prepared catalysts were characterized with XRD, BET, TEM and TGA. These catalysts were tested for DRM in a microtubular reactor at reaction conditions of 700 °C. The catalyst activity results show that the catalysts Ni/ZL (B) and Ca-Ni/ZL (B) give the highest methane conversion (60 %) with less time on stream stability compared with promoted Ni on ZL (A). In contrast, La-containing catalysts, La-Ni/ZL (B), show more time on stream stability with minimum carbon content for the spent catalyst indicating the enhancement of the promoters to the Ni/ZL (A) and (B), but with less catalytic activity performance in terms of methane and carbon dioxide conversions due to rapid catalyst deactivation.

  14. Intracluster atomic and electronic structural heterogeneities in supported nanoscale metal catalysts

    NARCIS (Netherlands)

    Elsen, A.; Jung, U.; Vila, F.; Li, Y.; Safonova, O.V.; Thomas, R.; Tromp, M.; Rehr, J.J.; Nuzzo, R.G.; Frenkel, A.I.

    2015-01-01

    This work reveals and quantifies the inherent intracluster heterogeneity in the atomic structure and charge distribution present in supported metal catalysts. The results demonstrate that these distributions are pronounced and strongly coupled to both structural and dynamic perturbations. They also

  15. Dehydrogenation of Isobutane with Carbon Dioxide over SBA-15-Supported Vanadium Oxide Catalysts

    Directory of Open Access Journals (Sweden)

    Chunling Wei

    2016-10-01

    Full Text Available A series of vanadia catalysts supported on SBA-15 (V/SBA with a vanadia (V content ranging from 1% to 11% were prepared by an incipient wetness method. Their catalytic behavior in the dehydrogenation of isobutane to isobutene with CO2 was examined. The catalysts were characterized by N2 adsorption, X-ray diffraction (XRD, scanning electron microscopy (SEM, Raman spectroscopy, and temperature-programmed reduction (TPR. It was found that these catalysts were effective for the dehydrogenation reaction, and the catalytic activity is correlated with the amount of dispersed vanadium species on the SBA-15 support. The 7% V/SBA catalyst shows the highest activity, which gives 40.8% isobutane conversion and 84.8% isobutene selectivity. The SBA-15-supported vanadia exhibits higher isobutane conversion and isobutene selectivity than the MCM-41-supported one.

  16. Effect of operational parameters and Pd/In catalyst in the reduction of nitrate using copper electrode.

    Science.gov (United States)

    Beltrame, Thiago Favarini; Coelho, Vanessa; Marder, Luciano; Ferreira, Jane Zoppas; Marchesini, Fernanda Albana; Bernardes, Andrea Moura

    2017-08-28

    Water with high concentration of nitrate may cause damage to health and to the environment. This study investigated how concentration, current density, flow, pH, the use of Pd/In catalyst and operating mode (constant current density and constant cell potential) have an influence in the electrochemical reduction of nitrate and in the formation of gaseous compounds using copper electrode. Experiments were performed in two-compartment electrolytic cells separated by a cationic membrane with nitrate model solutions prepared as a surrogate of concentrated brines from membrane desalination plants. The results show that the electroreduction process has potential for reduction of nitrate and that it is influenced by the operational conditions. The best conditions found for the treatment - with satisfactory reduction of nitrate, formation of gaseous compounds and reproducibility - were at nitrate concentrations of 600 and 1000 mg L-1, current density of 1.1 mA cm-2 and without pH control, since in these conditions the production of gaseous compounds is higher than the production of nitrite. When Pd/In catalyst was used, the nitrate reduction was 50% after 6 h of experiment and the predominant product were gaseous compounds. When compared to the experiment without the catalyst, the arrangement with Pd/In was the most efficient one.

  17. Nano carbon supported platinum catalyst interaction behavior with perfluorosulfonic acid ionomer and their interface structures

    DEFF Research Database (Denmark)

    Andersen, Shuang Ma

    2016-01-01

    , the ionomer may have an adsorption preference to the platinum nano particle rather than to the overall catalyst. This was verified by a close examination on the decomposition temperature of the carbon support and the ionomer. The electrochemical stability of the catalyst ionomer composite electrode suggests...... behavior of Nafion ionomer on platinized carbon nano fibers (CNFs), carbon nano tubes (CNTs) and amorphous carbon (Vulcan). The interaction is affected by the catalyst surface oxygen groups as well as porosity. Comparisons between the carbon supports and platinized equivalents are carried out. It reveals...

  18. Phenyl and ionic liquid based bifunctional periodic mesoporous organosilica supported copper: An efficient nanocatalyst for clean production of polyhydroquinolines.

    Science.gov (United States)

    Elhamifar, Dawood; Ardeshirfard, Hakimeh

    2017-11-01

    A novel phenyl and ionic liquid based bifunctional periodic mesoporous organosilica supported copper (Cu@BPMO-Ph-IL) is prepared, characterized and its catalytic application is developed in the clean production of polyhydroquinolines. The Cu@BPMO-Ph-IL was prepared via chemical grafting of ionic liquid groups onto phenyl-based PMO followed by treatment with copper acetate. This nanocatalyst was characterized with transmission electron microscopy (TEM), scanning electron microscopy (SEM), diffuse reflectance infrared Fourier transform spectroscopy (DRIFTs), thermal gravimetric analysis (TGA), powder X-ray diffraction (PXRD), nitrogen-sorption and energy dispersive X-ray (EDX) analyses. This was successfully applied in the one-pot Hantzsch condensation of aldehydes, ammonium acetate, alkylacetoacetates and dimedone to prepare a set of different derivatives of polyhydroquinolines in high yields and selectivity. The catalyst was effectively recovered and reused several times without important decrease in efficiency. The recovered catalyst was also characterized with TEM analysis to study its stability and durability under applied conditions. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. SSZ-13-supported manganese oxide catalysts for low temperature ...

    Indian Academy of Sciences (India)

    A series of Mn/SSZ-13 catalysts of varying Mn content were synthesized by hydrothermal and co-precipitation methods. Their performances for the selective catalytic reduction (SCR) of NOx with NH₃ were evaluated. The results indicate that over 95% NOx conversion was achieved at a low temperature of 150◦C with an Mn ...

  20. Preparation of Pt–Ru bimetallic catalyst supported on carbon ...

    Indian Academy of Sciences (India)

    Keywords. Carbon nanotubes; template synthesis; fuel cell catalyst; nanoparticles. Abstract. The template carbonization of polyphenyl acetylene yields hollow, uniform cylindrical carbon nanotubes with outer diameter almost equal to pore diameter of the template used. High resolution transmission electron microscopic ...

  1. β-Cyclodextrin for design of alumina supported cobalt catalysts efficient in Fischer-Tropsch synthesis.

    Science.gov (United States)

    Jean-Marie, Alan; Griboval-Constant, Anne; Khodakov, Andrei Y; Monflier, Eric; Diehl, Fabrice

    2011-10-14

    Addition of β-cyclodextrin during catalyst preparation strongly affects the structure and catalytic performance of alumina supported cobalt catalysts for Fischer-Tropsch synthesis. Impregnation of the support with solutions containing β-cyclodextrin leads to higher metal dispersion and spectacularly enhances both reaction rate and heavy hydrocarbons productivity in Fischer-Tropsch synthesis. This journal is © The Royal Society of Chemistry 2011

  2. Supported sub-nanometer Ta oxide clusters as model catalysts for the selective epoxidation of cyclooctene

    KAUST Repository

    Zwaschka, Gregor

    2018-01-22

    The preparation of organic ligands-free, isolated tantalum oxide atoms (Ta1) and small clusters (Tan>1) on flat silicate supports was accomplished by ultra-high vacuum (UHV) techniques followed by oxidation in air. The resulting surface complexes were thoroughly characterized and tested as supported catalysts for the epoxidation of cycloalkenes. The observed catalytic performance highlights the potential of the applied method for the production of active catalysts and the study of well-defined, ligand-free metal oxide moieties.

  3. Catalysts prepared from copper-nickel ferrites for the steam reforming of methanol

    Science.gov (United States)

    Huang, Yung-Han; Wang, Sea-Fue; Tsai, An-Pang; Kameoka, Satoshi

    2015-05-01

    In this study, Fe3O4-supported Cu and Ni catalysts are prepared through reduction of Cu-Ni (Ni1-xCuxFe2O4) ferrites. The Cu-Ni ferrites, synthesized using a solid-state reaction method, are reduced at temperatures from 240 °C to 500 °C in a H2 atmosphere. All ferrites are characterized with granular morphology and a smooth particle surface before reduction. For the CuFe2O4, Ni0.5Cu0.5Fe2O4 and NiFe2O4 ferrites reduced at 240, 300, and 400 °C, respectively, nanosized Cu and/or Ni particles (5-32 nm) and mesopores (5-30 nm) are distributed and adhered on the surfaces of Fe3O4 supports. After increasing the reduction temperature of NiFe2O4 ferrite to 500 °C, the Ni particles and mesopores disappear from the Fe3O4 surfaces, which is due to the formation of a Fe-Ni alloy covering on the Fe3O4 surfaces. The CuFe2O4 ferrite after H2 reduction at 240 °C exhibits the highest H2 production rate of 149 ml STP/min g-cat at 360 °C. The existence of Ni content in the Cu-Ni ferrites enhances the reverse water gas shift reaction, and raises the CO selectivity while reducing the CO2 selectivity. Formation of a Fe-Ni alloy exaggerates the trend and poisons the H2 production rate.

  4. Hydrogenation of Levulinic Acid over Nickel Catalysts Supported on Aluminum Oxide to Prepare γ-Valerolactone

    Directory of Open Access Journals (Sweden)

    Jie Fu

    2015-12-01

    Full Text Available Four types of nickel catalysts supported on aluminum oxide (Ni/Al2O3 with different nickel loadings were synthesized using the co-precipitation method and were used for the hydrogenation of levulinic acid (LA to prepare γ-valerolactone (GVL. The synthesized Ni/Al2O3 catalysts exhibited excellent catalytic activity in dioxane, and the activity of the catalysts was excellent even after being used four times in dioxane. The catalytic activity in dioxane as a solvent was found to be superior to the activity in water. Nitrogen physisorption, X-ray diffraction, and transmission electron microscopy were employed to characterize the fresh and used catalysts. The effects of the nickel loading, temperature, hydrogen pressure, and substrate/catalyst ratio on the catalytic activity were investigated.

  5. Carbon nanocages: A new support material for Pt catalyst with remarkably high durability

    Science.gov (United States)

    Wang, Xiao Xia; Tan, Zhe Hua; Zeng, Min; Wang, Jian Nong

    2014-01-01

    Low durability is the major challenge hindering the large-scale implementation of proton exchange membrane fuel cell (PEMFC) technology, and corrosion of carbon support materials of current catalysts is the main cause. Here, we describe the finding of remarkably high durability with the use of a novel support material. This material is based on hollow carbon nanocages developed with a high degree of graphitization and concurrent nitrogen doping for oxidation resistance enhancement, uniform deposition of fine Pt particles, and strong Pt-support interaction. Accelerated degradation testing shows that such designed catalyst possesses a superior electrochemical activity and long-term stability for both hydrogen oxidation and oxygen reduction relative to industry benchmarks of current catalysts. Further testing under conditions of practical fuel cell operation reveals almost no degradation over long-term cycling. Such a catalyst of high activity, particularly, high durability, opens the door for the next-generation PEMFC for “real world” application. PMID:24658614

  6. Dehydrogenation of light alkanes over rhenium catalysts on conventional and mesoporous MFI supports

    DEFF Research Database (Denmark)

    Rovik, Anne Krogh; Hagen, Anke; Schmidt, I.

    2006-01-01

    Recently, Re/HZSM-5 (Si/Al = 15) was shown to be an efficient catalyst for ethane dehydrogenation and aromatization at 823 K and atmospheric pressure. In this reaction, the major initial products were benzene, toluene and xylene (BTX), but increasing amounts of ethene were produced with time...... on stream due to deactivation of the catalyst. We show that by use of rhenium impregnated MFI supports with very few or no acidic sites (Si/Al > 500), highly selective ethane dehydrogenation catalysts are obtained with ethene selectivities of 98%. By use of mesoporous MFI supports (Si/Al > 500) the lifetime...... of the catalyst appears to be slightly improved compared to conventional MFI crystals. The beneficial effect of a mesoporous MFI support is convincingly demonstrated in propane dehydrogenation, where both conversion and selectivities on the mesoporous MFI (Si/Al > 500) impregnated with Re are significantly higher...

  7. Simple Copper(II) Schiff Base Complex as Efficient Heterogeneous Photo-Fenton-like Catalyst

    National Research Council Canada - National Science Library

    Fei, Bao-Li; Wang, Jiang-Hong; Yan, Qing-Ling; Liu, Qing-Bo; Long, Jian-Ying; Li, Yang-Guang; Shao, Kui-Zhan; Su, Zhong-Min; Sun, Wei-Yin

    2014-01-01

    ...) as photo-Fenton-like catalysts. Both 1 and 2 exhibited excellent catalytic performance without an acidification process, and the mononuclear complex 2 functioned better than the dinuclear complex 1...

  8. Influence of reduction time of copper based catalysts: Cu/Al2O3 and CuCr2O4 on hydrogenolysis of glycerol

    National Research Council Canada - National Science Library

    Wołosiak-Hnat, Agnieszka; Milchert, Eugeniusz; Lewandowski, Grzegorz; Grzmil, Barbara

    2011-01-01

    ... of glycerol to 1,2- and 1,3-propanediol. In the present study the influence of hydrogen reduction time of the Cu/Al2O3 and CuCr2O4 copper catalysts on glycerol conversion and selectivity of transformation to propanediols and by-products was studied...

  9. Local ammonia storage and ammonia inhibition in a monolithic copper-beta zeolite SCR catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Auvray, Xavier P [Chalmers University of Technology, Sweden; Partridge Jr, William P [ORNL; Choi, Jae-Soon [ORNL; Pihl, Josh A [ORNL; Yezerets, Alex [Cummins, Inc; Kamasamudram, Krishna [Cummins, Inc; Currier, Neal [Cummins, Inc; Olsson, Louise [Chalmers University of Technology, Sweden

    2012-01-01

    Selective catalytic reduction of NO with NH{sub 3} was studied on a Cu-beta zeolite catalyst, with specific focus on the distributed NH{sub 3} capacity utilization and inhibition. In addition, several other relevant catalyst parameter distributions were quantified including the SCR zone, or catalyst region where SCR occurs, and NO and NH{sub 3} oxidation. We show that the full NH{sub 3} capacity (100% coverage) is used within the SCR zone for a range of temperatures. By corollary, unused NH{sub 3} capacity exists downstream of the SCR zone. Consequently, the unused capacity relative to the total capacity is indicative of the portion of the catalyst unused for SCR. Dynamic NH{sub 3} inhibition distributions, which create local transient conversion inflections, are measured. Dynamic inhibition is observed where the gas phase NH{sub 3} and NO concentrations are high, driving rapid NH{sub 3} coverage buildup and SCR. Accordingly, we observe dynamic inhibition at low temperatures and in hydrothermally aged states, but predict its existence very near the catalyst front in higher conversion conditions where we did not specifically monitor its impact. While this paper addresses some general distributed SCR performance parameters including Oxidation and SCR zone, our major new contributions are associated with the NH{sub 3} capacity saturation within the SCR zone and dynamic inhibition distributions and the associated observations. These new insights are relevant to developing accurate models, designs and control strategies for automotive SCR catalyst applications.

  10. Possibilities of platinum recovery from metal supported spent auto catalysts

    Directory of Open Access Journals (Sweden)

    A. Fornalczyk

    2014-10-01

    Full Text Available The used auto catalytic converter is a valuable source of platinum group metals, so it is important to have it recycled in order to recover precious metals. World literature describes a number of pyro- or hydrometallurgical methods used for recovery of platinum from used automobile catalytic converters. However, all the methods, available in the literature, are used to recover platinum from ceramic carrier. Among automotive catalysts withdrawn from use, these with metallic carrier constitute quite a big group.

  11. Electrochemical dopamine sensor based on P-doped graphene: Highly active metal-free catalyst and metal catalyst support.

    Science.gov (United States)

    Chu, Ke; Wang, Fan; Zhao, Xiao-Lin; Wang, Xin-Wei; Tian, Ye

    2017-12-01

    Heteroatom doping is an effective strategy to enhance the catalytic activity of graphene and its hybrid materials. Despite a growing interest of P-doped graphene (P-G) in energy storage/generation applications, P-G has rarely been investigated for electrochemical sensing. Herein, we reported the employment of P-G as both metal-free catalyst and metal catalyst support for electrochemical detection of dopamine (DA). As a metal-free catalyst, P-G exhibited prominent DA sensing performances due to the important role of P doping in improving the electrocatalytic activity of graphene toward DA oxidation. Furthermore, P-G could be an efficient supporting material for loading Au nanoparticles, and resulting Au/P-G hybrid showed a dramatically enhanced electrocatalytic activity and extraordinary sensing performances with a wide linear range of 0.1-180μM and a low detection limit of 0.002μM. All these results demonstrated that P-G might be a very promising electrode material for electrochemical sensor applications. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Catalytic performance of activated carbon supported cobalt catalyst for CO2 reforming of CH4.

    Science.gov (United States)

    Zhang, Guojie; Su, Aiting; Du, Yannian; Qu, Jiangwen; Xu, Ying

    2014-11-01

    Syngas production by CO2 reforming of CH4 in a fixed bed reactor was investigated over a series of activated carbon (AC) supported Co catalysts as a function of Co loading (between 15 and 30wt.%) and calcination temperature (Tc=300, 400 or 500°C). The catalytic performance was assessed through CH4 and CO2 conversions and long-term stability. XRD and SEM were used to characterize the catalysts. It was found that the stability of Co/AC catalysts was strongly dependent on the Co loading and calcination temperature. For the loadings (25wt.% for Tc=300°C), stable activities have been achieved. The loading of excess Co (>wt.% 25) causes negative effects not only on the performance of the catalysts but also on the support surface properties. In addition, the experiment showed that ultrasound can enhance and promote dispersion of the active metal on the carrier, thus improving the catalytic performance of the catalyst. The catalyst activity can be long-term stably maintained, and no obvious deactivation has been observed in the first 2700min. After analyzing the characteristics, a reaction mechanism for CO2 reforming of CH4 over Co/AC catalyst was proposed. Copyright © 2014 Elsevier Inc. All rights reserved.

  13. Enhanced Activity of Supported Ni Catalysts Promoted by Pt for Rapid Reduction of Aromatic Nitro Compounds

    Directory of Open Access Journals (Sweden)

    Huishan Shang

    2016-06-01

    Full Text Available To improve the activities of non-noble metal catalysts is highly desirable and valuable to the reduced use of noble metal resources. In this work, the supported nickel (Ni and nickel-platinum (NiPt nanocatalysts were derived from a layered double hydroxide/carbon composite precursor. The catalysts were characterized and the role of Pt was analysed using X-ray diffraction (XRD, high-resolution transmission electron microscopy (HRTEM, energy dispersive X-ray spectroscopy (EDS mapping, and X-ray photoelectron spectroscopy (XPS techniques. The Ni2+ was reduced to metallic Ni0 via a self-reduction way utilizing the carbon as a reducing agent. The average sizes of the Ni particles in the NiPt catalysts were smaller than that in the supported Ni catalyst. The electronic structure of Ni was affected by the incorporation of Pt. The optimal NiPt catalysts exhibited remarkably improved activity toward the reduction of nitrophenol, which has an apparent rate constant (Ka of 18.82 × 10−3 s−1, 6.2 times larger than that of Ni catalyst and also larger than most of the reported values of noble-metal and bimetallic catalysts. The enhanced activity could be ascribed to the modification to the electronic structure of Ni by Pt and the effect of exposed crystal planes.

  14. Poly(N-4-vinylbenzyl-1,4,7-triazacyclononane Copper Complex Grafted Solid Catalyst for Oxidative Polymerization of 2,6-Dimethylphenol

    Directory of Open Access Journals (Sweden)

    Kei Saito

    2016-01-01

    Full Text Available A new solid phase catalyst, poly(N-4-vinylbenzyl-1,4,7-triazacyclononane copper(I complex, grafted onto polystyrene particles, has been employed for the oxidative polymerization of 2,6-dimethylphenol using an aqueous biphasic (water/toluene solvent system. The solid catalyst was synthesized by first grafting N-(4-vinylbenzyl-1,4,7-triaza-cyclononane onto polystyrene particles using a radical mediated polymerization method and next by creating the polymer-metal complex of copper-triazacyclononane with these modified particles. Poly(2,6-dimethyl-1,4-phenylene oxide was successfully obtained from the polymerization of 2,6-dimethylphenol using this new metal-organic solid phase catalyst.

  15. Non-noble catalysts and catalyst supports for phosphoric acid fuel cells

    Science.gov (United States)

    Mcalister, A. J.

    1981-01-01

    Tungsten carbide, which is active for hydrogen oxidation, is CO tolerant and has a hexagonal structure is discussed. Titanium carbide is inactive and has a cubic structure. Four different samples of the cubic alloys W sub x-1Ti sub XC sub 1-y were found to be active and CO tolerant. When the activities of these cubic alloys are weighted by the reciprocal of the square to those of highly forms of WC. They offer important insight into the nature of the active sites on W-C anode catalysts for use in phosphoric acid fuel cells.

  16. Control of interpenetration of copper-based MOFs on supported surfaces by electrochemical synthesis

    NARCIS (Netherlands)

    Sachdeva, S.; Pustovarenko, A.; Sudhölter, E.J.R.; Kapteijn, F.; De Smet, L.C.P.M.; Gascon, J.

    2016-01-01

    A study of a copper-based metal–organic framework (MOF) synthesized by an electrochemical route is presented. Morphological and adsorption properties of the MOF synthesized as bulk powder and on supported copper surfaces were investigated. Differences in these properties and structural refinement

  17. thesis of high-purity carbon nanotubes over alumina and silica supported bimetallic catalysts

    Directory of Open Access Journals (Sweden)

    Sanja Ratković

    2009-10-01

    Full Text Available Carbon nanotubes (CNTs were synthesized by a catalytic chemical vapor deposition method (CCVD of ethylene over alumina and silica supported bimetallic catalysts based on Fe, Co and Ni. The catalysts were prepared by a precipitation method, calcined at 600 °C and in situ reduced in hydrogen flow at 700 °C. The CNTs growth was carried out by a flow the mixture of C2H4 and nitrogen over the catalyst powder in a horizontal oven. The structure and morphology of as-synthesized CNTs were characterized using SEM. The as-synthesized nanotubes were purified by acid and basic treatments in order to remove impurities such as amorphous carbon, graphite nanoparticles and metal catalysts. XRD and DTA/TG analyses showed that the amounts of by-products in the purified CNTs samples were reduced significantly. According to the observed results, ethylene is an active carbon source for growing high-density CNTs with high yield but more on alumina-supported catalysts than on their silica- supported counterparts. The last might be explained by SMSI formed in the case of alumina-supported catalysts, resulting in higher active phase dispersion.

  18. Polystyrene-supported cu(II)-R-Box as recyclable catalyst in asymmetric Friedel–Crafts reaction

    KAUST Repository

    Desyatkin, V. G.

    2017-02-12

    The complex of copper(II) trifluoromethanesulfonate with chiral isopropyl bis(oxazoline) ligand (i-Pr-Box) was immobilized on accessible and inexpensive Merrifield resin according to a “click” procedure. The resulting catalyst showed high efficiency and recyclability in the asymmetric Friedel–Crafts alkylation of indole and its derivatives. The catalyst can be recycled five times without appreciable loss in activity and enantioselectivity.

  19. Investigation of altenative carbon materials for fuel-cell catalyst support

    DEFF Research Database (Denmark)

    Larsen, Mikkel Juul

    In order to ensure high utilization of the catalyst material in a polymer electrolyte membrane fuel cell (PEMFC) it is usually fixed in the form of nanoparticles on a supporting material. The catalyst is platinum or a platinum alloy, and the commonly used support is carbon black (CB). Although...... structured carbon forms such as graphitized CBs, carbon nanotubes (CNTs), and carbon nanofibres (CNFs). This thesis concerns the investigation of an array of different materials which may prospec-tively replace the conventional materials used in the catalyst. The study comprised 13 carbon samples which...... nanotubes (GMWCNTs), and graphitized carbon nanofibre (CNF), while the Pt/C samples were platinized samples of some of the CNTs and CNFs (Pt/FWCNT, Pt/GMWCNT, and Pt/CNF, respectively) as well as two commercial Pt/CB reference catalysts. Comparative analyses have been performed in order to be able to assess...

  20. Supercritical water gasification of microalga Nannochloropsis over supported Ni and Ru catalysts

    Science.gov (United States)

    Wijenayake, A. G. B. S. P.; Hassan, M.; Komiyama, M.

    2016-11-01

    Supercritical water gasification (SCWG) of a marine microalga Nannochloropsis was performed in the presence and the absence of supported Ru and Ni catalysts at 385 °C and 26 MPa using a batch reactor. The product gas of the non-catalytic reaction mainly comprised of CO2 while that of catalytic reaction produced CH4, CO2, H2 and some C2-C4 compounds. The addition of catalysts enhanced the decomposition and conversion (water-gas shift and methanation) reactions, consequently increasing the total gasification efficiency up to 92% for 60 min reaction time. Between the supported Ru and Ni catalysts, Ru resulted in higher gasification efficiency than Ni. Catalyst deactivation during SCWG of Nannochloropsis was also examined.

  1. Studies of supported metal catalysts. Progress report, September 1, 1980-August 31, 1981

    Energy Technology Data Exchange (ETDEWEB)

    Hercules, D.M.

    1981-04-01

    During this period research has been carried out on five separate catalyst systems. The effect of zinc ions on the interaction between cobalt and ..gamma..-Al/sub 2/O/sub 3/ has been studied. Work on the oxidic Mo/Al/sub 2/O/sub 3/ system has been published and studies have been extended to the sulfided catalysts. The first phase of work on the Co/Mo/Al/sub 2/O/sub 3/ system has been completed. Work on W/Al/sub 2/O/sub 3/ catalysts has begun and the oxidic system has been studied in some detail. Work continues on metal-support interactions in supported nickel catalysts. An electron spectroscopy (ESCA) study has been completed and work is continuing on correlation of the ESCA results with measurements like temperature programmed desorption (TPD) and temperature programmed reduction (TPRd).

  2. Preparation of Supported Metal Catalysts by Atomic and Molecular Layer Deposition for Improved Catalytic Performance

    Science.gov (United States)

    Gould, Troy D.

    Creating catalysts with enhanced selectivity and activity requires precise control over particle shape, composition, and size. Here we report the use of atomic layer deposition (ALD) to synthesize supported Ni, Pt, and Ni-Pt catalysts in the size regime (nanoparticles by depositing Ni on Al2O3 with two half-reactions of Ni(Cp)2 and H2. By changing the number of ALD cycles, Ni weight loadings were varied from 4.7 wt% to 16.7 wt% and the average particle sizes ranged from 2.5 to 3.3 nm, which increased the selectivity for C 3H6 hydrogenolysis by an order of magnitude over a much larger Ni/Al2O3 catalyst. Pt particles were deposited by varying the number of ALD cycles and the reaction chemistry (H2 or O 2) to control the particle size from approximately 1 to 2 nm, which allowed lower-coordinated surface atoms to populate the particle surface. These Pt ALD catalysts demonstrated some of the highest oxidative dehydrogenation of propane selectivities (37%) of a Pt catalyst synthesized by a scalable technique. Dry reforming of methane (DRM) is a reaction of interest due to the recent increased recovery of natural gas, but this reaction is hindered from industrial implementation because the Ni catalysts are plagued by deactivation from sintering and coking. This work utilized Ni ALD and NiPt ALD catalysts for the DRM reaction. These catalysts did not form destructive carbon whiskers and had enhanced reaction rates due to increased bimetallic interaction. To further limit sintering, the Ni and NiPt ALD catalysts were coated with a porous alumina matrix by molecular layer deposition (MLD). The catalysts were evaluated for DRM at 973 K, and the MLD-coated Ni catalysts outperformed the uncoated Ni catalysts in either activity (with 5 MLD cycles) or stability (with 10 MLD cycles). In summary, this thesis developed a new Ni nanoparticle ALD chemistry, explored possibilities for changing Pt ALD particle size, brought the two techniques together to create enhanced bimetallic

  3. Gallium-rich Pd-Ga phases as supported liquid metal catalysts

    Science.gov (United States)

    Taccardi, N.; Grabau, M.; Debuschewitz, J.; Distaso, M.; Brandl, M.; Hock, R.; Maier, F.; Papp, C.; Erhard, J.; Neiss, C.; Peukert, W.; Görling, A.; Steinrück, H.-P.; Wasserscheid, P.

    2017-09-01

    A strategy to develop improved catalysts is to create systems that merge the advantages of heterogeneous and molecular catalysis. One such system involves supported liquid-phase catalysts, which feature a molecularly defined, catalytically active liquid film/droplet layer adsorbed on a porous solid support. In the past decade, this concept has also been extended to supported ionic liquid-phase catalysts. Here we develop this idea further and describe supported catalytically active liquid metal solutions (SCALMS). We report a liquid mixture of gallium and palladium deposited on porous glass that forms an active catalyst for alkane dehydrogenation that is resistant to coke formation and is thus highly stable. X-ray diffraction and X-ray photoelectron spectroscopy, supported by theoretical calculations, confirm the liquid state of the catalytic phase under the reaction conditions. Unlike traditional heterogeneous catalysts, the supported liquid metal reported here is highly dynamic and catalysis does not proceed at the surface of the metal nanoparticles, but presumably at homogeneously distributed metal atoms at the surface of a liquid metallic phase.

  4. Modification by SiO2 of Alumina Support for Light Alkane Dehydrogenation Catalysts

    Directory of Open Access Journals (Sweden)

    Giyjaz E. Bekmukhamedov

    2016-10-01

    Full Text Available Due to the continuously rising demand for C3–C5 olefins it is important to improve the performance of catalysts for dehydrogenation of light alkanes. In this work the effect of modification by SiO2 on the properties of the alumina support and the chromia-alumina catalyst was studied. SiO2 was introduced by impregnation of the support with a silica sol. To characterize the supports and the catalysts the following techniques were used: low-temperature nitrogen adsorption; IR-spectroscopy; magic angle spinning 29Si nuclear magnetic resonance; temperature programmed desorption and reduction; UV-Vis-, Raman- and electron paramagnetic resonance (EPR-spectroscopy. It was shown that the modifier in amounts of 2.5–7.5 wt % distributed on the support surface in the form of SiOx-islands diminishes the interaction between the alumina support and the chromate ions (precursor of the active component. As a result, polychromates are the compounds predominantly stabilized on the surface of the modified support; under thermal activation of the catalyst and are reduced to the amorphous Cr2O3. This in turn leads to an increase in the activity of the catalyst in the dehydrogenation of isobutane.

  5. Enhanced Fuel Cell Catalyst Durability with Nitrogen Modified Carbon Supports

    Science.gov (United States)

    2013-02-12

    situ Small Angle X-ray Spectroscopy (SAXS) and X-ray diffraction (XRD) experiments were prepared by applying catalyst ink drop-wise to SGL Group company...2013-08-10 to IP F392 Journal of The Electrochemical Society, 160 (4) F389-F394 (2013) Table II. The values for Electrochemical Area ( ECA ) as...determined by CO stripping, the MOR specific activities, and percentage of ECA after 100× and 5000× cycles in the ADT protocol are tabulated. Specific

  6. Observing graphene grow: catalyst-graphene interactions during scalable graphene growth on polycrystalline copper.

    Science.gov (United States)

    Kidambi, Piran R; Bayer, Bernhard C; Blume, Raoul; Wang, Zhu-Jun; Baehtz, Carsten; Weatherup, Robert S; Willinger, Marc-Georg; Schloegl, Robert; Hofmann, Stephan

    2013-10-09

    Complementary in situ X-ray photoelectron spectroscopy (XPS), X-ray diffractometry, and environmental scanning electron microscopy are used to fingerprint the entire graphene chemical vapor deposition process on technologically important polycrystalline Cu catalysts to address the current lack of understanding of the underlying fundamental growth mechanisms and catalyst interactions. Graphene forms directly on metallic Cu during the high-temperature hydrocarbon exposure, whereby an upshift in the binding energies of the corresponding C1s XPS core level signatures is indicative of coupling between the Cu catalyst and the growing graphene. Minor carbon uptake into Cu can under certain conditions manifest itself as carbon precipitation upon cooling. Postgrowth, ambient air exposure even at room temperature decouples the graphene from Cu by (reversible) oxygen intercalation. The importance of these dynamic interactions is discussed for graphene growth, processing, and device integration.

  7. A Highly Practical Copper(I)/TEMPO Catalyst System for Chemoselective Aerobic Oxidation of Primary Alcohols

    Science.gov (United States)

    Hoover, Jessica M.; Stahl, Shannon S.

    2011-01-01

    Aerobic oxidation reactions have been the focus of considerable attention, but their use in mainstream organic chemistry has been constrained by limitations in their synthetic scope and by practical factors, such as the use of pure O2 as the oxidant or complex catalyst synthesis. Here, we report a new (bpy)CuI/TEMPO catalyst system that enables efficient and selective aerobic oxidation of a broad range of primary alcohols, including allylic, benzylic and aliphatic derivatives, to the corresponding aldehydes using readily available reagents, at room temperature with ambient air as the oxidant. The catalyst system is compatible with a wide range of functional groups and the high selectivity for 1° alcohols enables selective oxidation of diols that lack protecting groups. PMID:21861488

  8. The Electrochemical Performance and Durability of Carbon Supported Pt Catalyst in Contact with Aqueous and Polymeric Proton Conductors

    DEFF Research Database (Denmark)

    Andersen, Shuang Ma; Skou, Eivind Morten

    2014-01-01

    supported platinum catalyst in four different electrode structures: catalyst powder (CP), catalyst ionomer electrode (CIE), half membrane electrode assembly (HMEA) and full membrane electrode assembly (FMEA) in both ex-situ and in-situ experiments under a simulated start/stop cycle. We found...

  9. Iron oxide/cassava starch-supported Ziegler-Natta catalysts for in situ ethylene polymerization.

    Science.gov (United States)

    Chancharoenrith, Sittikorn; Kamonsatikul, Choavarit; Namkajorn, Montree; Kiatisevi, Supavadee; Somsook, Ekasith

    2015-03-06

    Iron oxide nanoparticles were used as supporters for in situ polymerization to produce polymer nanocomposites with well-dispersed fillers in polymer matrix. Iron oxide could be sustained as colloidal solutions by cassava starch to produce a good dispersion of iron oxide in the matrix. New supports based on iron oxide/cassava starch or cassava starch for Ziegler-Natta catalysts were utilized as heterogeneous supporters for partially hydrolyzed triethylaluminum. Then, TiCl4 was immobilized on the supports as catalysts for polymerization of ethylene. High-density polyethylene (HDPE) composites were obtained by the synthesized catalysts. A good dispersion of iron oxide/cassava starch particles was observed in the synthesized polymer matrix promoting to good mechanical properties of HDPE. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. High quality syngas production from microwave pyrolysis of rice husk with char-supported metallic catalysts.

    Science.gov (United States)

    Zhang, Shuping; Dong, Qing; Zhang, Li; Xiong, Yuanquan

    2015-09-01

    This study aimed to obtain the maximum possible gas yield and the high quality syngas production from microwave pyrolysis of rice husk with rice husk char and rice husk char-supported metallic (Ni, Fe and Cu) catalysts. The rice husk char-supported metallic catalysts had developed pore structure and catalytic activity for gas productions and tar conversion. The temperature-rising characteristic, product yields, properties of gas products and tar conversion mechanisms were investigated. It was found that three rice husk char-supported metallic catalysts improved the microwave absorption capability and increased heating rate and final temperature. Rice husk char-supported Ni catalyst presented most effective effects on gas production, e.g. the gas yield is 53.9%, and the volume concentration of desired syngas is 69.96%. Rice husk char-supported Ni and Fe catalysts played pivotal roles in tar conversion that less heavy compounds can be detected along with the reduction of organic compound number. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Nanosheet Supported Single-Metal Atom Bifunctional Catalyst for Overall Water Splitting.

    Science.gov (United States)

    Ling, Chongyi; Shi, Li; Ouyang, Yixin; Zeng, Xiao Cheng; Wang, Jinlan

    2017-08-09

    Nanosheet supported single-atom catalysts (SACs) can make full use of metal atoms and yet entail high selectivity and activity, and bifunctional catalysts can enable higher performance while lowering the cost than two separate unifunctional catalysts. Supported single-atom bifunctional catalysts are therefore of great economic interest and scientific importance. Here, on the basis of first-principles computations, we report a design of the first single-atom bifunctional eletrocatalyst, namely, isolated nickel atom supported on β 12 boron monolayer (Ni 1 /β 12 -BM), to achieve overall water splitting. This nanosheet supported SAC exhibits remarkable electrocatalytic performance with the computed overpotential for oxygen/hydrogen evolution reaction being just 0.40/0.06 V. The ab initio molecular dynamics simulation shows that the SAC can survive up to 800 K elevated temperature, while enacting a high energy barrier of 1.68 eV to prevent isolated Ni atoms from clustering. A viable experimental route for the synthesis of Ni 1 /β 12 -BM SAC is demonstrated from computer simulation. The desired nanosheet supported single-atom bifunctional catalysts not only show great potential for achieving overall water splitting but also offer cost-effective opportunities for advancing clean energy technology.

  12. Copper oxide as efficient catalyst for oxidative dehydrogenation of alcohols with air

    DEFF Research Database (Denmark)

    Poreddy, Raju; Engelbrekt, Christian; Riisager, Anders

    2015-01-01

    The oxidative dehydrogenation of alcohols to carbonyl compounds was studied using CuO nanoparticle catalysts prepared by solution synthesis in buffered media. CuO nanoparticles synthesized in N-cyclohexyl- 3-aminopropanesulfonic acid buffer showed high catalytic activity for the oxidation...

  13. Liquid phase catalytic hydrodebromination of tetrabromobisphenol A on supported Pd catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Ke [State Key Laboratory of Pollution Control and Resource Reuse, Jiangsu Key Laboratory of Vehicle Emissions Control, School of the Environment, Nanjing University, Nanjing 210023 (China); Zheng, Mengjia [Kuang Yaming Honors School, Nanjing University, Nanjing 210023 (China); Han, Yuxiang [State Key Laboratory of Pollution Control and Resource Reuse, Jiangsu Key Laboratory of Vehicle Emissions Control, School of the Environment, Nanjing University, Nanjing 210023 (China); Xu, Zhaoyi, E-mail: zhaoyixu@nju.edu.cn [State Key Laboratory of Pollution Control and Resource Reuse, Jiangsu Key Laboratory of Vehicle Emissions Control, School of the Environment, Nanjing University, Nanjing 210023 (China); Zheng, Shourong [State Key Laboratory of Pollution Control and Resource Reuse, Jiangsu Key Laboratory of Vehicle Emissions Control, School of the Environment, Nanjing University, Nanjing 210023 (China)

    2016-07-15

    Highlights: • Pd catalysts supported on TiO{sub 2}, CeO{sub 2}, Al{sub 2}O{sub 3} and SiO{sub 2} were prepared. • Deposition-precipitation method resulted in positively charged smaller Pd particle. • Complete debromination of tetrabromobisphenol A could be achieved on Pd/TiO{sub 2}. • Pd/TiO{sub 2} prepared by the deposition-precipitation method was more active. - Abstract: Tetrabromobisphenol A (TBBPA) is a widely used brominated flame retardant and reductive debromination is an effective method for the abatement of TBBPA pollution. In this study, Pd catalysts supported on TiO{sub 2}, CeO{sub 2}, Al{sub 2}O{sub 3} and SiO{sub 2} were prepared by the impregnation (the resulting catalyst denoted as im-Pd/support), deposition-precipitation (the resulting catalyst denoted as dp-Pd/support), and photo-deposition (the resulting catalyst denoted as pd-Pd/support) methods. The catalysts were characterized by N{sub 2} adsorption-desorption isotherm, X-ray diffraction, transmission electron microscopy, measurement of zeta potential, CO chemisorption, and X-ray photoelectron spectroscopy. The results showed that at an identical Pd loading amount (2.0 wt.%) Pd particle size in dp-Pd/TiO{sub 2} was much smaller than those in im-Pd/TiO{sub 2} and pd-Pd/TiO{sub 2}. Pd particle size of the dp-Pd/TiO{sub 2} catalyst increased with Pd loading amount. Additionally, Pd particles in the dp-Pd/TiO{sub 2} catalysts were positively charged due to the strong metal-support interaction, whereas the cationization effect was gradually attenuated with the increase of Pd loading amount. For the liquid phase catalytic hydrodebromination (HDB) of TBBPA, tri-bromobisphenol A (tri-BBPA), di-bromobisphenol A (di-BBPA), and mono-bromobisphenol A (mono-BBPA) were identified as the intermediate products, indicative of a stepwise debromination process. The catalytic HDB of TBBPA followed the Langmuir-Hinshelwood model, reflecting an adsorption enhanced catalysis mechanism. At an identical Pd

  14. Microwave-hydrothermal synthesis and characterization of nanostructured copper substituted ZnM2O4 (M = Al, Ga) spinels as precursors for thermally stable Cu catalysts

    Science.gov (United States)

    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

    2012-03-01

    Nanostructured CuxZn1-xAl2O4 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/Al2O3-based catalysts. The spinel nanoparticles exhibit an average size of approximately 5 nm and a high specific surface area (above 250 m2 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 m2 g-1. The catalytic performance of the material in CO2 hydrogenation and methanol steam reforming was compared with conventionally prepared Cu/ZnO/Al2O3 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 Zn2+ 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 m2 g-1 due to less copper incorporation is not a significant drawback for the methanol steam reforming.Nanostructured CuxZn1-xAl2O4 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/Al2O3-based catalysts. The spinel nanoparticles exhibit an average size of approximately 5 nm and a high specific surface area (above 250 m2 g-1). Cu nanoparticles of an average size of 3.3 nm can be formed by reduction of the spinel precursor in hydrogen

  15. Raney copper catalysts for the water-gas shift reaction: I. Preparation, activity and stability

    CSIR Research Space (South Africa)

    Mellor, JR

    1997-12-23

    Full Text Available disper- sion is expressed in terms of the ratio of the total number of surface atoms to the total number of metal atoms present. Copper particle volume-area mean diameter (dvA) was calculated according to the pro- cedure outlined by Anderson et al...

  16. Gold Catalysts on Y-Doped Ceria Supports for Complete Benzene Oxidation

    Directory of Open Access Journals (Sweden)

    Lyuba Ilieva

    2016-07-01

    Full Text Available Gold (3 wt. % catalysts on Y-doped (1, 2.5, 5 and 7.5 wt. % Y2O3 ceria supports prepared by coprecipitation (CP or impregnation (IM were studied in complete benzene oxidation (CBO. A low-extent Y modification was chosen to avoid ordering of oxygen vacancies. The samples were characterized by XRD, TGA, XPS and TPR techniques. A positive role of air pretreatment at 350 °C as compared to 200 °C was established for all Y-containing catalysts and it was explained by cleaning the active sites from carbonates. The oxygen supply cannot be considered as a limiting step for benzene oxidation except for the high 7.5%-doped samples, as suggested by TGA and TPR data. On the basis of XPS results of fresh and used in CBO catalysts, the presence of cationic gold species does not seem important for high CBO activity. The gold catalyst on an IM support with 1% Y-doping exhibited the best performance. A 100% benzene conversion was achieved only over this catalyst and Au/ceria, while it was not reached even at 300 °C over all other studied catalysts. Gold and ceria particle agglomeration or coke formation should be excluded as a possible reason, and the most probable explanation could be associated with the importance of the benzene activation stage.

  17. Characterization of a surface modified carbon cryogel and a carbon supported Pt catalyst

    Directory of Open Access Journals (Sweden)

    BILJANA M. BABIĆ

    2007-08-01

    Full Text Available A carbon cryogel, synthesized by carbonization of a resorcinol/formaldehyde cryogel and oxidized in nitric acid, was used as catalyst support for Pt nano-particles. The Pt/C catalyst was prepared by a modified polyol synthesis method in an ethylene glycol (EG solution. Characterization by nitrogen adsorption showed that the carbon cryogel support and the Pt/C catalyst were mesoporous materials with high specific surface areas (SBET > 400 m2 g-1 and large mesoporous volumes. X-Ray diffraction of the catalyst demonstrated the successful reduction of the Pt precursor to metallic form. TEM Images of the Pt/C catalyst and Pt particle size distribution showed that the mean Pt particle size was about 3.3 nm. Cyclic voltammetry (CV experiments at various scan rates (from 2 to 200 mV s-1 were performed in 0.5 mol dm-3 HClO4 solution. The large capacitance of the oxidized carbon cryogel electrode, which arises from a combination of the double-layer capacitance and pseudocapacitance, associated with the participation of surface redox-type reactions was demonstrated. For the oxidized carbon cryogel, the total specific capacitance determined by 1/C vs. ν0.5 extrapolation method was found to be 386 F g-1. The hydrogen oxidation reaction at the investigated Pt/C catalyst proceeded as an electrochemically reversible, two-electron direct discharge reaction.

  18. Enhanced Activity and Selectivity of Carbon Nanofiber Supported Pd Catalysts for Nitrite Reduction

    KAUST Repository

    Shuai, Danmeng

    2012-03-06

    Pd-based catalyst treatment represents an emerging technology that shows promise to remove nitrate and nitrite from drinking water. In this work we use vapor-grown carbon nanofiber (CNF) supports in order to explore the effects of Pd nanoparticle size and interior versus exterior loading on nitrite reduction activity and selectivity (i.e., dinitrogen over ammonia production). Results show that nitrite reduction activity increases by 3.1-fold and selectivity decreases by 8.0-fold, with decreasing Pd nanoparticle size from 1.4 to 9.6 nm. Both activity and selectivity are not significantly influenced by Pd interior versus exterior CNF loading. Consequently, turnover frequencies (TOFs) among all CNF catalysts are similar, suggesting nitrite reduction is not sensitive to Pd location on CNFs nor Pd structure. CNF-based catalysts compare favorably to conventional Pd catalysts (i.e., Pd on activated carbon or alumina) with respect to nitrite reduction activity and selectivity, and they maintain activity over multiple reduction cycles. Hence, our results suggest new insights that an optimum Pd nanoparticle size on CNFs balances faster kinetics with lower ammonia production, that catalysts can be tailored at the nanoscale to improve catalytic performance for nitrite, and that CNFs hold promise as highly effective catalyst supports in drinking water treatment. © 2012 American Chemical Society.

  19. Controlled metal nitrate decomposition for the preparation of supported metal Catalysts

    NARCIS (Netherlands)

    Wolters, M.

    2010-01-01

    High surface area supported metal (oxide) catalysts are essential for the production of fuels, chemicals, pharmaceuticals and the abatement of environmental pollution. Impregnation of high surface area supports, often silica or alumina, followed by drying, calcination and reduction is one of the

  20. Reusable and Efficient Polystryrene-supported Acidic Ionic Liquid Catalyst for Mononitration of Aromatic Compounds

    Energy Technology Data Exchange (ETDEWEB)

    Li, Li Xia; Ling, Qi Long; Liu, Zu Liang; Xing, Xiao Dong; Zhu, Xiao Qin; Meng, Xiao [Nanjing Univ. of Science and Technology, Nanjing (China)

    2012-10-15

    A series of polystyrene-supported 1-(propyl-3-sulfonate)-3-methyl-imidazolium hydrosulfate acidic ionic liquid (PS-[SO{sub 3}H-PMIM][HSO{sub 4}]) catalysts were prepared and tested for mononitration of simple aromatics compounds with nitric acid. It was found that the reactivity of the catalysts increased with increasing [SO{sub 3}HPMIM][HSO{sub 4}] content. The para-selectivity was not only related to the [SO{sub 3}H-PMIM][HSO{sub 4}] content but also the substituent groups in aromatics. A reaction mechanism of nitration over this new catalyst was proposed. The catalytic activity of this catalyst decreased slightly after fifth runs in the synthesis of nitrotoluene.

  1. Fe phase complexes and their thermal stability in iron phosphate catalysts supported on silica

    Science.gov (United States)

    Dasireddy, Venkata D. B. C.; Bharuth-Ram, K.; Harilal, A.; Singh, S.; Friedrich, H. B.

    2015-04-01

    Comparative XRD and Mössbauer spectroscopy studies have been conducted on the effect of temperature on the phase transformations of an iron phosphate catalyst synthesized using the ammonia gel method (CAT1) and a commercial grade FePO 4 catalyst supported on silica using wet impregnation method (CAT2). The XRD patterns of both catalysts showed the presence of iron phosphate and the tridymite phase of aluminum phosphate. Mössbauer spectra of the catalysts show that the phases present in CAT1 are thermally stable up to 500 ∘C, but CAT2 shows significant changes with the tridymite phase of iron phosphate increasing from 6 % to 29 % of the spectral area at a temperature of 500 ∘C.

  2. Fe phase complexes and their thermal stability in iron phosphate catalysts supported on silica

    Energy Technology Data Exchange (ETDEWEB)

    Dasireddy, Venkata D. B. C., E-mail: dasireddy@gmail.com; Bharuth-Ram, K.; Harilal, A.; Singh, S.; Friedrich, H. B. [University of KwaZulu-Natal, School of Chemistry and Physics (South Africa)

    2015-04-15

    Comparative XRD and Mössbauer spectroscopy studies have been conducted on the effect of temperature on the phase transformations of an iron phosphate catalyst synthesized using the ammonia gel method (CAT1) and a commercial grade FePO {sub 4} catalyst supported on silica using wet impregnation method (CAT2). The XRD patterns of both catalysts showed the presence of iron phosphate and the tridymite phase of aluminum phosphate. Mössbauer spectra of the catalysts show that the phases present in CAT1 are thermally stable up to 500 {sup ∘}C, but CAT2 shows significant changes with the tridymite phase of iron phosphate increasing from 6 % to 29 % of the spectral area at a temperature of 500 {sup ∘}C.

  3. Preparation of Mesoporous Silica-Supported Palladium Catalysts for Biofuel Upgrade

    Directory of Open Access Journals (Sweden)

    Ling Fei

    2012-01-01

    Full Text Available We report the preparation of two hydrocracking catalysts Pd/CoMoO4/silica and Pd/CNTs/CoMoO4/silica (CNTs, carbon nanotubes. The structure, morphologies, composition, and thermal stability of catalysts were studied by X-ray diffraction (XRD, scanning electron microscopy (SEM, Raman spectroscopy, transmission electron microscopy (TEM, energy-dispersive X-ray (EDX, and thermogravimetric analysis (TGA. The catalyst activity was measured in a Parr reactor with camelina fatty acid methyl esters (FAMEs as the feed. The analysis shows that the palladium nanoparticles have been incorporated onto mesoporous silica in Pd/CoMoO4/silica or on the CNTs surface in Pd/CNTs/CoMoO4/silica catalysts. The different combinations of metals and supports have selective control cracking on heavy hydrocarbons.

  4. Chitosan as a Natural Polymer for Heterogeneous Catalysts Support: A Short Review on Its Applications

    Directory of Open Access Journals (Sweden)

    Mengshan Lee

    2015-11-01

    Full Text Available Chitosan, a bio-based polymer which has similar characteristics to those of cellulose, exhibits cationic behavior in acidic solutions and strong affinity for metals ions. Thus, it has received increased attention for the preparation of heterogeneous catalysts. Recent studies demonstrated that chitosan-based catalysts had high sorption capacities, chelating activities, stability and versatility, which could be potentially applied as green reactants in various scientific and engineering applications. This study intends to review the recent development of chitosan-based catalysts, particularly in the aspects of the main mechanisms for preparing the materials and their applications in environmental green chemistry. Studies on the preparation of catalyst nanoparticles/nanospheres supported on chitosan were also reviewed.

  5. Liquid-phase Hydrogenation of Phenol to Cyclohexanone over Supported Palladium Catalysts

    Directory of Open Access Journals (Sweden)

    Lihui Fan

    2016-10-01

    Full Text Available The ZSM-5, g-Al2O3, SiO2 and MgO supported Pd-catalysts were prepared for the phenol hydrogenation to cyclohexanone in liquid-phase. The natures of these catalysts were characterized by XRD, N2 adsorption-desorption analysis, H2-TPR, CO2-TPD and NH3-TPD. The catalytic performance of the supported Pd-catalyst for phenol hydrogenation to cyclohexanone is closely related to nature of the support and the size of Pd nanoparticles. The Pd/MgO catalyst which possesses higher basicity shows higher cyclohexanone selectivity, but lower phenol conversion owing to the lower specific surface area. The Pd/SiO2 catalyst prepared by precipitation gives higher cyclohexanone selectivity and phenol conversion, due to the moderate amount of Lewis acidic sites, and the smaller size and higher dispersion of Pd nanoparticles on the surface. Under the reaction temperature of 135 oC and H2 pressure of 1 MPa, after reacting for 3.5 h, the phenol conversion of 71.62% and the cyclohexanone selectivity of 90.77% can be obtained over 0.5 wt% Pd/SiO2 catalyst. Copyright © 2016 BCREC GROUP. All rights reserved Received: 7th March 2016; Revised: 13rd May 2016; Accepted: 7th June 2016 How to Cite: Fan, L., Zhang, L., Shen, Y., Liu, D., Wahab, N., Hasan, M.M. (2016. Liquid-phase Hydrogenation of Phenol to Cyclohexanone over Supported Palladium Catalysts. Bulletin of Chemical Reaction Engineering & Catalysis, 11 (3: 354-362 (doi: 10.9767/bcrec.11.3.575.354-362 Permalink/DOI: http://doi.org/10.9767/bcrec.11.3.575.354-362

  6. In situ synthesis of nanoclay filled polyethylene using polymer supported metallocene catalyst system

    Directory of Open Access Journals (Sweden)

    Z. V. P Murthy

    2011-01-01

    Full Text Available In situ ethylene polymerizations were performed using bis(cyclopentadienetitanium dichloride supported on polyethersulfone as catalyst. The bis(cyclopentadienetitanium dichloride supported on polyethersulfone catalyst activity estimated by ethylene polymerization was 360 kgPE/molTi/h. During polymerization the fillers used were montmorillionite nanoclays having surface modifications with 35-45 wt% dimethyl dialkyl(14-18amine (FA and 25-30 wt% trimethyl stearyl ammonium (FB. These fillers were pretreated with methylaluminoxine (MAO; cocatalyst for better dispersion onto the polymer matrix. The formation of polyethylene within the whole matrix was confirmed by FTIR studies. It was found that the nature of nanofiller did not have any remarkable effect on the melting characteristics of the polymer. TGA study indicates that nanoclay FB filled polyethylene has higher thermal stability than nanoclay FA filled polyethylene. The melting temperature of the obtained polyethylenes was 142 ºC, which corresponds to that synthesized by the polyether sulfone supported catalyst.

  7. Vanadia-based SCR Catalysts Supported on Tungstated and Sulfated Zirconia: Influence of Doping with Potassium

    DEFF Research Database (Denmark)

    Due-Hansen, Johannes; Boghosian, Soghomon; Kustov, Arkadii

    2007-01-01

    A series of vanadium-based SCR catalysts supported on sulfated or tungstated ZrO2 were synthesized and characterized by means of N2-BET, XRD, NH3-TPD and in situ Raman spectroscopy. The effect of potassium doping on the properties of vanadia species is studied in detail. A number of catalyst...... and morphology, the surface composition and the molecular configuration of the dispersed vanadates. It was observed that poisoning with potassium had a negligible effect on the surface vanadate species (especially the V=O stretching frequency observed by in situ Raman spectroscopy) if supported on the sulfated...... the observed decrease in V=O stretching frequency and the higher proportion of dimers and higher polymers through coordination between K+ and two neighbouring V=O. The results suggest an increased resistance towards potassium doping for the vanadia-based catalysts supported on sulfated zirconia....

  8. Graphite oxide-supported CaO catalysts for transesterification of soybean oil with methanol.

    Science.gov (United States)

    Zu, Yanhong; Tang, Jianyuan; Zhu, Wanchun; Zhang, Min; Liu, Gang; Liu, Yan; Zhang, Wenxiang; Jia, Mingjun

    2011-10-01

    Graphite oxide (GO) supported CaO catalysts were prepared and successfully applied to the transesterification of soybean oil with methanol. The supports and resultant catalysts were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), N(2) adsorption, thermogravimetry (TG), X-ray photoelectron spectroscopy (XPS), temperature-programed desorption (TPD) and Fourier-transform infrared spectroscopy (FT-IR). The GO supported CaO catalysts exhibited excellent catalytic activity and were easily regenerated by simple heat-treatment. The oxygen-containing groups (i.e., hydroxyl, epoxide groups and carboxyl groups) present on the surface of GO likely act as anchoring centers for CaO. This work demonstrates that graphite oxide is an effective host material of catalytically active CaO nanoparticles for the transesterification of soybean oil with methanol to produce biodiesel. Copyright © 2011 Elsevier Ltd. All rights reserved.

  9. Biodiesel production from waste cooking oil using copper doped zinc oxide nanocomposite as heterogeneous catalyst.

    Science.gov (United States)

    Gurunathan, Baskar; Ravi, Aiswarya

    2015-01-01

    A novel CZO nanocomposite was synthesized and used as heterogeneous catalyst for transesterification of waste cooking oil into biodiesel using methanol as acyl acceptor. The synthesized CZO nanocomposite was characterized in FESEM with an average size of 80 nm as nanorods. The XRD patterns indicated the substitution of ZnO in the hexagonal lattice of Cu nanoparticles. The 12% (w/w) nanocatalyst concentration, 1:8 (v:v) O:M ratio, 55 °C temperature and 50 min of reaction time were found as optimum for maximum biodiesel yield of 97.71% (w/w). Hence, the use of CZO nanocomposite can be used as heterogeneous catalyst for biodiesel production from waste cooking oil. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Atomic XAFS as a Tool To Probe the Reactivity of Metal Oxide Catalysts: Quantifying Metal Oxide Support Effects

    NARCIS (Netherlands)

    Keller, D.E.; Airaksinen, S.M.K.; Krause, A.O.I.; Weckhuysen, B.M.|info:eu-repo/dai/nl/285484397; Koningsberger, D.C.|info:eu-repo/dai/nl/073704342

    2007-01-01

    The potential of atomic XAFS (AXAFS) to directly probe the catalytic performances of a set of supported metal oxide catalysts has been explored for the first time. For this purpose, a series of 1 wt % supported vanadium oxide catalysts have been prepared differing in their oxidic support material

  11. Advanced catalyst supports for PEM fuel cell cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Du, Lei; Shao, Yuyan; Sun, Junming; Yin, Geping; Liu, Jun; Wang, Yong

    2016-11-01

    Electrocatalyst support materials are key components for polymer exchange membrane (PEM) fuel cells, which play a critical role in determining electrocatalyst durability and activity, mass transfer and water management. The commonly-used supports, e.g. porous carbon black, cannot meet all the requirements under the harsh operation condition of PEM fuel cells. Great efforts have been made in the last few years in developing alternative support materials. In this paper, we selectively review recent progress on three types of important support materials: carbon, non-carbon and hybrid carbon-oxides nanocomposites. A perspective on future R&D of electrocatalyst support materials is also provided.

  12. Palladium Catalyst Supported on Zeolite for Cross-coupling Reactions: An Overview of Recent Advances.

    Science.gov (United States)

    Kumbhar, Arjun

    2017-02-01

    Over the last 30-40 years, Pd-catalyzed C-C bond-forming reactions have gained immense importance for their use in synthesis of biologically and pharmaceutically important organic fragments. Heterogeneous Pd catalysts supported on porous materials, especially zeolites, have many advantages as they have high surface area with tunable acidity and basicity, hydrophobic and hydrophilic character, shape and size selectivity, as well as chemical and thermal stability. They also offer very easy recovery and reusability. This review covers the literature published on the synthesis and characterization of Pd catalysts supported on zeolites and their applications in various organic transformations.

  13. Copper(II tetrafluoroborate as mild and versatile catalyst for the

    Directory of Open Access Journals (Sweden)

    Jihillu. S. Yadav

    2008-12-01

    Full Text Available A variety of -acetamido ketones and ketoesters are readily prepared in high yields under extremelymild conditions via a three component coupling of aromatic aldehydes, enolizable ketones or -ketoesters andnitriles in the presence of 10 mol% of copper(II tetrafluoroborate and a stoichiometric amount of acetylchloride. A solution of 10 mol% of Cu(BF42 in acetonitrile provides a convenient reaction medium to carry out athree component reaction under mild conditions

  14. Supporting PtRu catalysts on various types of carbon nanomaterials for fuel cell applications

    Science.gov (United States)

    Suda, Yoshiyuki; Ozaki, Masahiro; Tanoue, Hideto; Takikawa, Hirofumi; Ue, Hitoshi; Shimizu, Kazuki; Muramoto, Hirokazu

    2013-04-01

    PtRu catalysts were supported on five types of carbon nanomaterials of various shapes, sizes, and graphitic properties and the catalyst supports evaluated. The carbon nanomaterial used included three types of nanoparticles: Arc Black (AcB), Vulcan XC-72 (Vulcan) and graphene oxide (GO), and two types of nanofibers: carbon nanocoil (CNC) and carbon nanotube (CNT). Pt and Ru were supported by the reduction method using sodium borohydride. The metal catalyst loading was confirmed by thermo-gravimetric analysis (TGA), electron microscopy, and X-ray diffraction (XRD). Transmission electron microscopy (TEM) and XRD revealed that the diameter of PtRu catalyst nanoparticles loaded on reduced GO (rGO) and AcB were ~2 nm and was the smallest among all the samples. Shifts in Pt (111) XRD peaks of CNC and CNT were larger than those of AcB, Vulcan, and rGO. These results suggest that the diameters of catalyst nanoparticles became smaller by loading on the carbon nanoparticles with a large surface area including rGO, AcB, and Vulcan. Loading onto the carbon nanofibers enhanced the degree of PtRu alloying.

  15. Monodisperse metal nanoparticle catalysts on silica mesoporous supports: synthesis, characterizations, and catalytic reactions

    Energy Technology Data Exchange (ETDEWEB)

    Somorjai, G.A.

    2009-09-14

    The design of high performance catalyst achieving near 100% product selectivity at maximum activity is one of the most important goals in the modern catalytic science research. To this end, the preparation of model catalysts whose catalytic performances can be predicted in a systematic and rational manner is of significant importance, which thereby allows understanding of the molecular ingredients affecting the catalytic performances. We have designed novel 3-dimensional (3D) high surface area model catalysts by the integration of colloidal metal nanoparticles and mesoporous silica supports. Monodisperse colloidal metal NPs with controllable size and shape were synthesized using dendrimers, polymers, or surfactants as the surface stabilizers. The size of Pt, and Rh nanoparticles can be varied from sub 1 nm to 15 nm, while the shape of Pt can be controlled to cube, cuboctahedron, and octahedron. The 3D model catalysts were generated by the incorporation of metal nanoparticles into the pores of mesoporous silica supports via two methods: capillary inclusion (CI) and nanoparticle encapsulation (NE). The former method relies on the sonication-induced inclusion of metal nanoparticles into the pores of mesoporous silica, whereas the latter is performed by the encapsulation of metal nanoparticles during the hydrothermal synthesis of mesoporous silica. The 3D model catalysts were comprehensively characterized by a variety of physical and chemical methods. These catalysts were found to show structure sensitivity in hydrocarbon conversion reactions. The Pt NPs supported on mesoporous SBA-15 silica (Pt/SBA-15) displayed significant particle size sensitivity in ethane hydrogenolysis over the size range of 1-7 nm. The Pt/SBA-15 catalysts also exhibited particle size dependent product selectivity in cyclohexene hydrogenation, crotonaldehyde hydrogenation, and pyrrole hydrogenation. The Rh loaded SBA-15 silica catalyst showed structure sensitivity in CO oxidation reaction. In

  16. The tungsten heteropolyacid supported on activated bentonites as catalyst for selective oxidation of 2-propanol

    Energy Technology Data Exchange (ETDEWEB)

    Rožić, Ljiljana; Grbić, Boško [IChTM, Department of Catalysis and Chemical Engineering, University of Belgrade, Belgrade, 11000 (Serbia); Petrović, Srđan, E-mail: srlepp@nanosys.ihtm.bg.ac.rs [IChTM, Department of Catalysis and Chemical Engineering, University of Belgrade, Belgrade, 11000 (Serbia); Radić, Nenad [IChTM, Department of Catalysis and Chemical Engineering, University of Belgrade, Belgrade, 11000 (Serbia); Damjanović, Ljiljana [Faculty of Physical Chemistry, University of Belgrade, Belgrade, 11000 (Serbia); Vuković, Zorica [IChTM, Department of Catalysis and Chemical Engineering, University of Belgrade, Belgrade, 11000 (Serbia)

    2015-11-01

    This paper provides the correlation between the catalytic activity and selectivity of catalysts with various loadings of heteropolyacids over bentonite in the vapour phase 2-propanol oxidation. The catalysts are characterised by energy dispersive spectroscopy, differential scanning calorimeter, ammonia temperature programmed desorption, infrared spectroscopy and a nitrogen adsorption/desorption method. Energy dispersive spectroscopy results have shown satisfactory agreement regarding chemical composition that corresponds to the desired content of heteropolyacids on bentonite. Thermal analysis confirmed the thermal stability of catalysts under the investigated region of oxidation reaction. NH{sub 3}-TPD spectra demonstrated that all catalysts include two types of acidic sites: weak adsorption centres up to 390 K and a broad distribution of stronger acidic sites at higher temperatures. The catalysts were active in the vapour-phase conversion of 2-propanol to acetone in the temperature region of 343–553 K. An increase of HPW loading improves selectivity towards acetone formation. - Highlights: • HPW content has an evident effect on the micro- and mesoporous phase ratio. • TPD spectra of ammonia demonstrated that all catalysts include two types of acidic sites. • Acetone is a product of the reaction over Keggin anion as results of dehydrogenation process. • The conversion and product selectivity increase with the HPW loading on support.

  17. Selective Ring Opening of 1-Methylnaphthalene Over NiW-Supported Catalyst Using Dealuminated Beta Zeolite.

    Science.gov (United States)

    Kim, Eun-Sang; Lee, You-Jin; Kim, Jeong-Rang; Kim, Joo-Wan; Kim, Tae-Wan; Chae, Ho-Jeong; Kim, Chul-Ung; Lee, Chang-Ha; Jeong, Soon-Yong

    2016-02-01

    Nanoporous Beta zeolite was dealuminated by weak acid treatment for reducing the acidity. Bi-functional catalysts were prepared using commercial Beta zeolites and the dealuminated zeolites for acidic function, NiW for metallic function. 1-Methylnaphthalene was selected as a model compound for multi-ring aromatics in heavy oil, and its selective ring opening reaction has been investigated using the prepared bi-functional catalysts with different acidity in fixed bed reaction system. The dealuminated Beta zeolites, which crystal structure and nanoporosity were maintained, showed the higher SiO2/Al2O3 ratio and smaller acidity than their original zeolite. NiW-supported catalyst using the dealuminated Beta zeolite with SiO2/Al203 mole ratio of 55 showed the highest performance for the selective ring opening. The acidity of catalyst seemed to play an important role as active sites for the selective ring opening of 1-methylnaphthalene but there should be some optimum catalyst acidity for the reaction. The acidity of Beta zeolite could be controlled by the acid treatment and the catalyst with the optimum acidity for the selective ring opening could be prepared.

  18. Effect of chemically reduced palladium supported catalyst on sunflower oil hydrogenation conversion and selectivity

    Directory of Open Access Journals (Sweden)

    Abdulmajid Alshaibani

    2017-02-01

    Full Text Available Catalytic hydrogenation of sunflower oil was studied in order to improve the conversion and to reduce the trans-isomerization selectivity. The hydrogenation was performed using Pd–B/γ-Al2O3 prepared catalyst and Pd/Al2O3 commercial catalyst under similar conditions. The Pd–B/γ-Al2O3 catalyst was prepared by wet impregnation and chemical reduction processes. It was characterized by Brunauer–Emmett–Teller surface area analysis (BET, X-ray powder diffraction (XRD, scanning electron microscopy (SEM, and transmission electron microscopy (TEM. The result of sunflower oil hydrogenation on Pd–B/γ-Al2O3 catalyst showed a 17% higher conversion and a 23% lower trans-isomerization selectivity compared to the commercial Pd/Al2O3 catalyst. The chemical reduction of palladium supported catalyst using potassium borohydride (KBH4 has affected the Pd–B/γ-Al2O3 catalyst’s structure and particle size. These most likely influenced its catalytic performance toward higher conversion and lower trans-isomerization selectivity.

  19. Understanding properties of engineered catalyst supports using contact angle measurements and X-ray reflectivity.

    Science.gov (United States)

    Amama, Placidus B; Islam, Ahmad E; Saber, Sammy M; Huffman, Daniel R; Maruyama, Benji

    2016-02-07

    There is significant interest in broadening the type of catalyst substrates that support the growth of high-quality carbon nanotube (CNT) carpets. In this study, ion beam bombardment has been utilized to modify catalyst substrates for CNT carpet growth. Using a combination of contact angle measurements (CAMs) and X-ray reflectivity (XRR) for the first time, new correlations between the physicochemical properties of pristine and engineered catalyst substrates and CNT growth behavior have been established. The engineered surfaces obtained after exposure to different degrees of ion beam damage have distinct physicochemical properties (porosity, layer thickness, and acid-base properties). The CAM data were analyzed using the van Oss-Chaudhury-Good model, enabling the determination of the acid-base properties of the substrate surfaces. For the XRR data, a Fourier analysis of the interference patterns enabled extraction of layer thickness, while the atomic density and interfacial roughness were extracted by analyzing the amplitude of the interference oscillations. The dramatic transformation of the substrate from "inactive" to "active" is attributed to a combined effect of substrate porosity or damage depth and Lewis basicity. The results reveal that the efficiency of catalyst substrates can be further improved by increasing the substrate basicity, if the minimum surface porosity is established. This study advances the use of a non-thermochemical approach for catalyst substrate engineering, as well as demonstrates the combined utility of CAM and XRR as a powerful, nondestructive, and reliable tool for rational catalyst design.

  20. Alumina supported molybdenum catalyst for lignin valorization: Effect of reduction temperature.

    Science.gov (United States)

    Ma, Xiaolei; Cui, Kai; Hao, Wenyue; Ma, Rui; Tian, Ye; Li, Yongdan

    2015-09-01

    Alumina supported molybdenum catalysts were prepared with an impregnation method. The activity of the catalyst in the ethanolysis of Kraft lignin to C6-C11 molecules, i.e. alcohols, esters, monophenols, benzyl alcohols and arenes, was tested in a batch reactor at 280 °C with initial 0 MPa nitrogen. The complete conversion of lignin to small molecular chemicals was achieved without the formation of tar or char. The reduction temperature during the catalyst preparation was proved to have a profound effect on the activity of the catalyst. The overall product yield firstly increases and then decreases with the increase of the reduction temperature in a range of 500-800 °C. The maximum yield up to 1390 mg/g lignin was obtained with the catalyst reduced at 750 °C. Furthermore, the catalyst showed an excellent recyclability, where no significant loss of the catalytic activity was exhibited after 5 runs. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Spherical carbon capsules with hollow macroporous core and mesoporous shell structures as a highly efficient catalyst support in the direct methanol fuel cell.

    Science.gov (United States)

    Chai, Geun Seok; Yoon, Suk Bon; Kim, Jung Ho; Yu, Jong-Sung

    2004-12-07

    Carbon capsules with hollow core and mesoporous shell (HCMS) structures were used as a support material for Pt(50)-Ru(50) catalyst, and the catalytic performance of the HCMS supported catalyst in the direct methanol fuel cell was described; the HCMS carbon supported catalysts exhibited much higher specific activity for methanol oxidation than the commonly used E-TEK catalyst by about 80%, proving that the HCMS carbon capsules are an excellent support for electrode catalysts in DMFC.

  2. Carbon-supported platinum alloy catalysts for phenol hydrogenation for making industrial chemicals

    Energy Technology Data Exchange (ETDEWEB)

    Srinivas, S.T.; Song, C.

    1999-07-01

    Phenol is available in large quantities in liquids derived from coal and biomass. Phenol hydrogenation is an industrially important reaction to produce cyclohexanone and cyclohexanol. Cyclohexane, cyclohexene and benzene are obtained as minor products in this reaction. Cyclohexanone is an important intermediate in the production of caprolactam for nylon 6 and cyclohexanol for adipic acid production. In USA, cyclohexanol and cyclohexanone are produced by benzene hydrogenation to cyclohexane over nickel or noble metal catalysts, followed by oxidation of cyclohexane to produce a mixture of cyclohexanol and cyclohexanone. Then cyclohexanol is dehydrogenated in the presence of Cu-Zn catalyst to cyclohexanone. Usually phenol hydrogenation is also carried out by using Ni catalyst in liquid phase. However, a direct single-step vapor phase hydrogenation of phenol to give cyclohexanone selectively is more advantageous in terms of energy savings and process economics, since processing is simplified and the endothermic step of cyclohexanol dehydrogenation can be avoided, as demonstrated by Montedipe and Johnson Matthey using promoted Pd/Al{sub 2}O{sub 3} catalyst. While it is not the purpose of this paper to dwell on the relative merits of these routes, it is necessary to mention that while using monometallic catalysts, generally the problem of catalyst deactivation of sintering as well as coking is frequently encountered. Addition and alloying of noble metal (e.g. Pt) with a second metal can result in a catalyst with better selectivity and activity in the reaction which is more resistant to deactivation. This paper presents the results on the single-step vapor phase hydrogenation of phenol over carbon-supported Pt-M (M=Cr, V, Zr) alloy catalysts to yield mainly cyclohexanone or cyclohexanol.

  3. Highly dispersed metal catalyst

    Science.gov (United States)

    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.

  4. Perlite as a potential support for nickel catalyst in the process of sunflower oil hydrogenation

    Science.gov (United States)

    Radonjić, V.; Krstić, J.; Lončarević, D.; Jovanović, D.; Vukelić, N.; Stanković, M.; Nikolova, D.; Gabrovska, M.

    2015-12-01

    Investigation was conducted in order to elucidate the possibility of using perlite as support for preparation of nickel based precursor catalyst, potentially applicable in vegetable oil hydrogenation process. On three differently prepared expanded perlite, nickel catalyst precursors with identical Ni/SiO2 = 1.1 and Ni/Mg = 10/1 ratios were synthesized by precipitation-deposition method. Different techniques, SEM micrography, He-pycnometry, calcimetry, Hg-porosimetry, N2-physisorption, H2-chemisorption and temperature programmed reduction, were used for characterization of obtained samples. Determining the precursor texture, morphology and reducibility shows a successfully deposited nickel phase on perlite support with promising properties for vegetable oil hydrogenation. Chosen precursor was reduced and passivated in paraffin oil and the obtained catalyst showed significant catalytic activity in the test of sunflower oil hydrogenation.

  5. Formic acid electrooxidation on carbon supported platinum catalyst with preferential plane orientation

    Directory of Open Access Journals (Sweden)

    Krstajić Mila N.

    2015-01-01

    Full Text Available Pt-based nanocatalysts supported on Vulcan XC-72R carbon, were prepared by water-in-oil microemulsion method, with addition of various amounts of HCl in the water phase. Polyethileneglycoldodecylether (BRIJ 30 was used as a surfactant, which influenced the Pt surface structure, along with HCl. Catalysts prepared with addition of 0, 15, 25 and 35 % of HCl during the synthesis, were electrochemically characterised in 0,5 M H2SO4 using cyclic voltammetry and CO oxidation. Formic acid electrooxidation was examined on all investigated catalysts, in terms of their electrocatalytic activity and stability. Platinum loading on carbon support was examined by Thermogravimetric analysis. Catalysts showed different features in hydrogen region, and slight differences in formic acid oxidation mechanisms.

  6. Removal of toluene by sequential adsorption-plasma oxidation: Mixed support and catalyst deactivation.

    Science.gov (United States)

    Qin, Caihong; Huang, Xuemin; Zhao, Junjie; Huang, Jiayu; Kang, Zhongli; Dang, Xiaoqing

    2017-07-15

    A sequential adsorption-plasma oxidation system was used to remove toluene from simulated dry air using γ-Al 2 O 3 , HZSM-5, a mixture of the two materials or their supported Mn-Ag catalyst as adsorbents under atmospheric pressure and room temperature. After 120min of plasma oxidation, γ-Al 2 O 3 had a better carbon balance (∼75%) than HZSM-5, but the CO 2 yield of γ-Al 2 O 3 was only ∼50%; and there was some desorption of toluene when γ-Al 2 O 3 was used. When a mixture of HZSM-5 and γ-Al 2 O 3 with a mass ratio of 1/2 was used, the carbon balance was up to 90% and 82% of this was CO 2 . The adsorption performance and electric discharge characteristics of the mixed supports were tested in order to rationalize this high CO x yield. After seven cycles of sequential adsorption-plasma oxidation, support and Mn-Ag catalyst deactivation occurred. The support and catalyst were characterized before and after deactivation by SEM, a BET method, XRD, XPS and GC-MS in order to probe the mechanism of their deactivation. 97.6% of the deactivated supports and 76% of the deactivated catalysts could be recovered by O 2 temperature-programmed oxidation. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Synthesising Fe-Mo catalysts supported on silica for the selective oxidation of methane to formaldehyde

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Guerrero Fajardo

    2010-05-01

    Full Text Available The selective oxidation of methane to formaldehyde was analysed using iron-molybdenum catalysts supported on silica prepared by the sol-gel method which leads to obtaining a greater surface area and high iron and molybdenum metal dispersion on the si-lica’s amorphous surface. Seven catalysts were prepared, one of them as silica support, another as 0.5% wt iron load without molybdenum and the remaining five having 0.1%-1.0% weight molybdenum and 0.5% wt iron loads. The highest BET areas were 830 and 879 m2.g-1 for catalysts 2 (0.5% Fe - 0% Mo and 4 (0.5% Fe - 0.3% Mo respectively, having 28% average micropo-rosity and 47% average mesoporosity. X-ray diffraction confirmed the catalysts’ amorphous structure. The TPR spectrum showed low hydrogen consumption attributed to the absence of isolated Fe and Mo species. ESCA analysis revealed the same Fe/Mo a-tomic ratio on the catalyst surface as in the bulk preparation. Catalytic activity was carried out at atmospheric pressure, CH4/ O2/N2 = 7.5/1/4 reaction mixture, 400-800°C temperature interval. Catalysts 4 (0.5% Fe - 0.3% Mo, 5 (0.5% Fe - 0.5% Mo and 7 (0.5% Fe - 1.0% Mo displayed greater methane conversion, whereas catalysts 5 (0.5% Fe - 0.5% Mo, 4 (0.5% Fe - 0.3% Mo, 2 (0.5% Fe - 0% Mo and 7 (0.5% Fe - 1.0% Mo gave better formaldehyde product results. The highest conversion per- centage (4.07% mol was presented at 700°C for catalyst 4 (0.5% Fe-0.3% Mo. Formaldehyde yield was 202,0 gHCHO.kg-1 cata.h-1 at this temperature.

  8. Theoretical study of the catalytic CO oxidation by Pt catalyst supported on Ge-doped grapheme.

    Science.gov (United States)

    Tang, Yanan; Yang, Zongxian; Dai, Xianqi; Lu, Zhansheng; Zhang, Yanxing; Fu, Zhaoming

    2014-09-01

    The geometry, electronic structure and catalytic properties of the anchored Pt atom on the Ge-doped graphene (Pt/Ge-graphene) substrates are investigated using the first-principles computations. It is found that Ge atoms can form strong covalent bonds with the carbon atoms at the vacancy site on the defective graphene. The Ge-graphene as substrate can effectively anchored Pt atoms and form supported Pt catalyst, which exhibits good catalytic activity for CO oxidation with a two-step route, starting with the Langmuir-Hinshelwood (LH) reaction followed by the Eley-Rideal (ER) reaction. The Ge dopant in graphene plays a vital role in enhancing the substrate-adsorbate interaction through facilitating the charge redistribution at their interfaces. The Ge-graphene can be used as the reactive support to control the stability and activity of the Pt catalysts. This work provides valuable guidance on fabricating carbon-based catalysts for CO oxidation, and validates the reactivity of single-atom catalyst for designing atomic-scale catalysts.

  9. Production of hydrogen for fuel cells by steam reforming of ethanol over supported noble metal catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Liguras, Dimitris K.; Kondarides, Dimitris I.; Verykios, Xenophon E. [Department of Chemical Engineering, University of Patras, GR-26504 Patras (Greece)

    2003-07-25

    The catalytic performance of supported noble metal catalysts for the steam reforming (SR) of ethanol has been investigated in the temperature range of 600-850C with respect to the nature of the active metallic phase (Rh, Ru, Pt, Pd), the nature of the support (Al{sub 2}O{sub 3}, MgO, TiO{sub 2}) and the metal loading (0-5wt.%). It is found that for low-loaded catalysts, Rh is significantly more active and selective toward hydrogen formation compared to Ru, Pt and Pd, which show a similar behavior. The catalytic performance of Rh and, particularly, Ru is significantly improved with increasing metal loading, leading to higher ethanol conversions and hydrogen selectivities at given reaction temperatures. The catalytic activity and selectivity of high-loaded Ru catalysts is comparable to that of Rh and, therefore, ruthenium was further investigated as a less costly alternative. It was found that, under certain reaction conditions, the 5% Ru/Al{sub 2}O{sub 3} catalyst is able to completely convert ethanol with selectivities toward hydrogen above 95%, the only byproduct being methane. Long-term tests conducted under severe conditions showed that the catalyst is acceptably stable and could be a good candidate for the production of hydrogen by steam reforming of ethanol for fuel cell applications.

  10. Slurry-phase Fischer-Tropsch synthesis and kinetic studies over supported cobalt carbonyl derived catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Withers, H.P. Jr.; Eliezer, K.F.; Mitchell, J.W. (Air Products and Chemicals, Inc., Allentown, PA (USA))

    1990-09-01

    This paper reports the preparation characterization, and performance of cobalt carbonyl cluster based catalysts for use in slurry-phase Fischer--Tropsch (FT) technology investigated. Using metal carbonyls as active metal precursors allows for the control of metal particle size on the support surface, thus offering the potential for better control of activity and selectivity of the FT reaction. Silica as the support provided the highest catalyst activities. A Co{sub 2}(CO){sub 8}/Zr(OPr){sub 4}/SiO{sub 2} catalyst (3.5% cobalt, 6.6% zirconium) was developed as the most active system in the FT slurry reactor and also gave the best liquid fuel selectivity. Selectivity patterns correlated to the Schulz--Flory prediction. These catalysts exhibited low water/gas shift activity. Diesel fuel product produced by this catalyst was high quality. A kinetic expression that took water inhibition into account was verified, yielding an activation energy of 97 kJ/mol for syngas conversion ranging from 34% to 71% at 240--280{degrees} C.

  11. Hydrogen production from biomass gasification using biochar as a catalyst/support.

    Science.gov (United States)

    Yao, Dingding; Hu, Qiang; Wang, Daqian; Yang, Haiping; Wu, Chunfei; Wang, Xianhua; Chen, Hanping

    2016-09-01

    Biochar is a promising catalyst/support for biomass gasification. Hydrogen production from biomass steam gasification with biochar or Ni-based biochar has been investigated using a two stage fixed bed reactor. Commercial activated carbon was also studied as a comparison. Catalyst was prepared with an impregnation method and characterized by X-ray diffraction, specific surface and porosity analysis, X-ray fluorescence and scanning electron micrograph. The effects of gasification temperature, steam to biomass ratio, Ni loading and bio-char properties on catalyst activity in terms of hydrogen production were explored. The Ni/AC catalyst showed the best performance at gasification temperature of 800°C, S/B=4, Ni loading of 15wt.%. Texture and composition characterization of the catalysts suggested the interaction between volatiles and biochar promoted the reforming of pyrolysis volatiles. Cotton-char supported Ni exhibited the highest activity of H2 production (64.02vol.%, 92.08mgg(-1) biomass) from biomass gasification, while rice-char showed the lowest H2 production. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Carbon-supported PtAu alloy nanoparticle catalysts for enhanced electrocatalytic oxidation of formic acid

    Science.gov (United States)

    Chen, Guoqin; Li, Yunhua; Wang, Dong; Zheng, Li; You, Guirong; Zhong, Chuan-Jian; Yang, Lefu; Cai, Fan; Cai, Junxiu; Chen, Bing H.

    2011-10-01

    The understanding of the electrocatalytic activity of bimetallic nanoparticle catalysts requires the ability to precisely control the composition and phase properties. In this report, we describe a new strategy in the preparation of a series of carbon supported platinum-gold bimetallic nanoparticles with various bimetallic compositions which were loaded onto a carbon black support and subjected subsequently by thermal treatment (Pt100-mAum/C). The Pt100-mAum/C catalysts are characterized by X-ray diffraction (XRD), transmission electron spectroscopy (TEM), and induced coupled plasma-atomic emission spectroscopy (ICP-AES). The XRD pattern for the bimetallic nanoparticles shows single-phase alloy character. This ability enabled us to establish the correlation between the bimetallic composition and the electrocatalytic activity for formic acid (FA) electrooxidation. The electrocatalytic activities of the catalysts toward FA oxidation reaction are shown to strongly depend on the bimetallic PtAu composition. Within a wide range of bimetallic composition, the Pt50Au50/C catalyst shows the highest electrocatalytic activity for the FA oxidation, with a mass activity eight times higher than that of Pt/C. The high performance of the PtAu/C catalyst can be ascribed to the increased selectivity toward the FA dehydrogenation at the decreased availability of adjacent Pt atoms.

  13. Enhancing the stability of copper chromite catalysts for the selective hydrogenation of furfural using ALD overcoating

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Hongbo; Lei, Yu; Kropf, A. Jeremy; Zhang, Guanghui; Elam, Jeffrey W.; Miller, Jeffrey T.; Sollberger, Fred; Ribeiro, Fabio; Akatay, M. Cem; Stach, Eric A.; Dumesic, James A.; Marshall, Christopher L.

    2014-08-01

    The stability of a gas-phase furfural hydrogenation catalyst (CuCr2O4 center dot CuO) was enhanced by depositing a thin Al2O3 layer using atomic layer deposition (ALD). Based on temperature-programed reduction (TPR) measurements, the reduction temperature of Cu was raised significantly, and the activation energy for furfural reduction was decreased following the ALD treatment. Thinner ALD layers yielded higher furfural hydrogenation activities. X-ray absorption fine structure (XAFS) spectroscopy studies indicated that Cu1+/Cu-0 are the active species for furfural reduction.

  14. Efficient Boron-Copper Additions to Aryl-Substituted Alkenes Promoted by NHC–Based Catalysts. Enantioselective Cu-Catalyzed Hydroboration Reactions

    OpenAIRE

    Lee, Yunmi; Hoveyda, Amir H.

    2009-01-01

    A Cu-catalyzed method for efficient boron-copper addition processes involving acyclic and cyclic disubstituted aryl olefins are reported. Reactions are promoted with 0.5–5 mol % of a readily available N-heterocyclic carbene (NHC) complex; the presence of MeOH promotes in situ protonation of the C–Cu bond and leads to efficient catalyst turnover, constituting a net Cu-catalyzed hydroboration process. Reactions proceed in >98:

  15. Reversing Size-Dependent Trends in the Oxidation of Copper Clusters through Support Effects: Reversing Size-Dependent Trends in the Oxidation of Copper Clusters through Support Effects

    Energy Technology Data Exchange (ETDEWEB)

    Mammen, Nisha [Theoretical Sciences Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, -560064 Bangalore India; Spanu, Leonardo [Shell Technology Center, Shell India Markets Private Limited, -560048 Bangalore India; Tyo, Eric C. [Materials Science Division, Argonne National Laboratory, 60439 Argonne IL USA; Yang, Bing [Materials Science Division, Argonne National Laboratory, 60439 Argonne IL USA; Halder, Avik [Materials Science Division, Argonne National Laboratory, 60439 Argonne IL USA; Seifert, Sönke [X-ray Science Division, Argonne National Laboratory, 60439 Argonne IL USA; Pellin, Michael J. [Materials Science Division, Argonne National Laboratory, 60439 Argonne IL USA; Vajda, Stefan [Materials Science Division, Argonne National Laboratory, 60439 Argonne IL USA; Institute for Molecular Engineering, The University of Chicago, 60637 Chicago IL USA; Narasimhan, Shobhana [Theoretical Sciences Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, -560064 Bangalore India

    2017-12-22

    Having the ability to tune the oxidation state of Cu nanoparticles is essential for their utility as catalysts. The degree of oxidation that maximizes product yield and selectivity is known to vary, depending on the particular reaction. Using first principles calculations and XANES measurements, we show that for subnanometer sizes in the gas phase, smaller Cu clusters are more resistant to oxidation. However, this trend is reversed upon deposition on an alumina support. We are able to explain this result in terms of strong cluster-support interactions, which differ significantly for the oxidized and elemental clusters. The stable cluster phases also feature novel oxygen stoichiometries. Our results suggest that one can tune the degree of oxidation of Cu catalysts by optimizing not just their size, but also the support they are deposited on.

  16. Supported cobalt catalysts by one-pot aqueous combustion synthesis for catalytic phenol degradation.

    Science.gov (United States)

    Sun, Hongqi; Liang, Hanwen; Zhou, Guanliang; Wang, Shaobin

    2013-03-15

    Cobalt oxides (Co) and Al(2)O(3)-, SiO(2)-, and TiO(2)-supported cobalt oxide catalysts were prepared by an aqueous combustion method using urea and glycine as fuels. Their catalytic performance in activation of OXONE® for phenol degradation in aqueous solution was investigated. It was found that unsupported Co oxide and supported Co oxide presented different mechanisms in activation of OXONE® for phenol degradation. The supported Co catalysts presented higher activity in activation of OXONE® for phenol degradation due to higher dispersion of Co(3)O(4) on the supports and Co(II) coordination sites. The major oxidizing radicals were identified to be SO(4)(-) by competitive radical reactions. The Co oxides synthesized from urea or glycine showed a similar activity; however, the supported Co catalysts prepared by glycine fuel exhibited better activity than those prepared by urea. For Al(2)O(3)-, SiO(2)-, and TiO(2)-supported Co catalysts, Co/TiO(2) presented a higher activity in phenol degradation compared with Co/SiO(2) and Co/Al(2)O(3). But, Co/SiO(2) showed the best stability among the catalysts. Total organic carbon could be reduced by 80%, 72%, and 45% on Co/TiO(2), Co/SiO(2), and Co/Al(2)O(3), respectively, at 30 ppm phenol. Phenol degradation was found to follow the zero-order kinetics. The causes of deactivation were investigated, and the regeneration methods were proposed. Copyright © 2012 Elsevier Inc. All rights reserved.

  17. Supported Rh-phosphine complex catalysts for continuous gas-phase decarbonylation of aldehydes

    DEFF Research Database (Denmark)

    Malcho, Phillip; Garcia-Suarez, Eduardo J.; Mentzel, Uffe Vie

    2014-01-01

    Heterogeneous silica supported rhodium-phosphine complex catalysts are employed for the first time in the catalytic decarbonylation of aldehydes in continuous gas-phase. The reaction protocol is exemplified for the decarbonylation of p-tolualdehyde to toluene and further extended to other aromati...

  18. Stability and kinetic studies of supported ionic liquid phase catalysts for hydroformylation of propene

    DEFF Research Database (Denmark)

    Riisager, Anders; Fehrmann, Rasmus; Haumann, Marco

    2005-01-01

    Supported ionic liquid phase (SILP) catalysts have been studied with regard to their long-term stability in the continuous gas-phase hydroformylation of propene. Kinetic data have been acquired by variation of temperature, pressure, syngas composition, substrate concentration, and residence time...

  19. Silica-supported ionic liquid as highly efficient catalyst for one-pot ...

    Indian Academy of Sciences (India)

    supported ionic liquid as highly efficient catalyst for one-pot synthesis of acenaphtho[1,2-b]furan compounds. REZA SANDAROOSa,∗, MOHAMMAD TAGHI GOLDANIb,∗ and SAMAN DAMAVANDIc. aDepartment of Chemistry, Faculty of Science, ...

  20. Towards stable catalysts by control over the collective features of supported metal nanoparticles

    NARCIS (Netherlands)

    Prieto, G.; Zecevic, J.|info:eu-repo/dai/nl/341386715; Friedrich, H.|info:eu-repo/dai/nl/304837350; de Jong, K.P.|info:eu-repo/dai/nl/06885580X; de Jongh, P.E.|info:eu-repo/dai/nl/186125372

    2013-01-01

    Supported metal nanoparticles play a pivotal role in areas such as nanoelectronics, energy storage/conversion1 and as catalysts for the sustainable production of fuels and chemicals2–4. However, the tendency of nanoparticles to grow into larger crystallites is an impediment for stable

  1. Catalytic Ring Hydrogenation of Benzoic Acid with Supported Transition Metal Catalysts in scCO2

    Directory of Open Access Journals (Sweden)

    Fengyu Zhao

    2007-07-01

    Full Text Available The ring hydrogenation of benzoic acid to cyclohexanecarboxylic acid overcharcoal-supported transition metal catalysts in supercritical CO2 medium has been studiedin the present work. The cyclohexanecarboxylic acid can be produced efficiently insupercritical CO2 at the low reaction temperature of 323 K. The presence of CO2 increasesthe reaction rate and several parameters have been discussed.

  2. Highly Selective Continuous Gas-Phase Methoxycarbonylation of Ethylene with Supported Ionic Liquid Phase (SILP) Catalysts

    DEFF Research Database (Denmark)

    Khokarale, Santosh Govind; Garcia Suárez, Eduardo José; Fehrmann, Rasmus

    2017-01-01

    Supported ionic liquid phase (SILP) technology was applied for the first time to the Pd-catalyzed continuous, gas-phase methoxycarbonylation of ethylene to selectively produce methyl propanoate (MP) in high yields. The influence of catalyst and reaction parameters such as, for example, ionic liquid...

  3. Calcium Oxide Supported on Monoclinic Zirconia as a Highly Active Solid Base Catalyst

    NARCIS (Netherlands)

    Frey, A.M.; Haasterecht, van T.; Jong, de K.P.; Bitter, J.H.

    2013-01-01

    Calcium oxide supported on ZrO2 is a highly active catalyst for base-catalyzed reactions such as aldol-type reactions and transesterification reactions. The role of key parameters during preparation, that is, impregnation versus precipitation, heat treatment, and metal oxide loading on the basicity

  4. Hydrogen peroxide modified Mg-Al-O oxides supported Pt-Sn catalysts for paraffin dehydrogenation

    NARCIS (Netherlands)

    Lai, Y.; He, Songbo; Luo, S.; Bi, W.; Li, XianRu; Sun, Chenglin; Seshan, Kulathuiyer

    2015-01-01

    In this work, a new method to prepare Mg–Al–O oxide by co-precipitation method with addition of H2O2 was developed. The application of Mg–Al–O as a support of Pt–Sn catalysts for paraffin dehydrogenation was investigated. Characterization results indicated that modification of H2O2 (i) enlarged the

  5. Selective Hydrodeoxygenation of Alkyl Lactates to Alkyl Propionates with Fe-based Bimetallic Supported Catalysts

    DEFF Research Database (Denmark)

    Khokarale, Santosh Govind; He, Jian; Schill, Leonhard

    2018-01-01

    Hydrodeoxygenation (HDO) of methyl lactate (ML) to methyl propionate (MP) was performed with various base-metal supported catalysts. A high yield of 77 % MP was obtained with bimetallic Fe-Ni/ZrO2 in methanol at 220 °C and 50 bar H2 . A synergistic effect of Ni increased the yield of MP significa...

  6. Aerobic oxidation of aldehydes under ambient conditions using supported gold nanoparticle catalysts

    DEFF Research Database (Denmark)

    Marsden, Charlotte Clare; Taarning, Esben; Hansen, David

    2008-01-01

    A new, green protocol for producing simple esters by selectively oxidizing an aldehyde dissolved in a primary alcohol has been established, utilising air as the oxidant and supported gold nanoparticles as catalyst. The oxidative esterifications proceed with excellent selectivities at ambient...

  7. Partially unzipped carbon nanotubes as a superior catalyst support for PEM fuel cells.

    Science.gov (United States)

    Long, Donghui; Li, Wei; Qiao, Wenming; Miyawaki, Jin; Yoon, Seong-Ho; Mochida, Isao; Ling, Licheng

    2011-09-07

    Partially unzipped carbon nanotubes prepared by strong oxidation and thermal expansion of carbon nanotubes were explored as an advanced catalyst support for PEM fuel cells. The unique hybrid structure of 1D nanotube and 2D double-side graphene resulted in an outstanding electrocatalytic performance. This journal is © The Royal Society of Chemistry 2011

  8. Immobilization of carbon nanofibers (CNFs) on a stainless steel filter as a catalyst support layer

    NARCIS (Netherlands)

    Roemers-van Beek, J. M.; van Ommen, J. G.; Lefferts, L.

    2018-01-01

    A layer of carbon nanofiber (CNF) agglomerates is used to produce a catalyst support layer that can be immobilized on a stainless steel filter and that can be removed when desired. For immobilization a filtration procedure is developed that produces a stable CNF layer at relatively low shear force

  9. Immobilization of carbon nanofibers (CNFs) on a stainless steel filter as a catalyst support layer

    NARCIS (Netherlands)

    Roemers-van Beek, J.M.; van Ommen, J.G.; Lefferts, Leonardus

    2018-01-01

    Abstract A layer of carbon nanofiber (CNF) agglomerates is used to produce a catalyst support layer that can be immobilized on a stainless steel filter and that can be removed when desired. For immobilization a filtration procedure is developed that produces a stable CNF layer at relatively low

  10. Immobilization of carbon nanofibers (CNFs) on a stainless steel filter as a catalyst support layer

    NARCIS (Netherlands)

    Roemers-van Beek, J. M.; van Ommen, J. G.; Lefferts, L.

    2017-01-01

    A layer of carbon nanofiber (CNF) agglomerates is used to produce a catalyst support layer that can be immobilized on a stainless steel filter and that can be removed when desired. For immobilization a filtration procedure is developed that produces a stable CNF layer at relatively low shear force

  11. The selective catalytic reduction of NO with NH3 over supported vanadia catalysts

    NARCIS (Netherlands)

    Weckhuysen, B.M.; Wachs, I.E.; Deo, G.; Andreini, A; Vuurman, M.A.; Boer, M. de; Amiridis, M.D.

    1996-01-01

    The selective catalytic reduction (SCR) of NO with NH3was systematically investigated over a series of supported vanadia catalysts to obtain additional insight into this important industrial reaction. The influence of surface vanadia coverage, promoters (surface tungsten oxide, niobium oxide, and

  12. Carbon nanotubes: A promising catalyst support material for supercritical water gasification of biomass waste

    NARCIS (Netherlands)

    de Vlieger, Dennis; Thakur, D.B.; Lefferts, Leonardus; Seshan, Kulathuiyer

    2012-01-01

    Supercritical water (SCW) as a reaction medium is especially promising for the production of renewable chemicals from biomass. Stability issues of catalyst support materials in SCW are a major setback for these reactions and hinder the further development and industrial exploitation of this

  13. A comprehensive model for the supported vanadium oxide catalyst: The umbrella model

    NARCIS (Netherlands)

    Lingen, J.N.J. van

    2006-01-01

    Supported vanadium oxide catalysts are widely used in industry. However, the molecular structure of the active species, responsible for the actual catalysis, is for a large part still unknown. This thesis describes four years study on the elucidation of this molecular structure. It mainly focuses on

  14. Recent progress in diffuse reflectance spectroscopy of supported metal oxide catalysts

    NARCIS (Netherlands)

    Weckhuysen, B.M.; Schoonheydt, R.A.

    1999-01-01

    Diffuse reflectance spectroscopy is a suitable technique for studying heterogeneous catalysts, as both d-d and charge transfer transitions of supported transition metal ions can be probed. Within the past several years, new developments have resulted in a more detailed understanding of the surface

  15. Mesoporous palladium–copper ferrites as highly efficient and magnetically separable catalysts for Suzuki coupling reaction

    Energy Technology Data Exchange (ETDEWEB)

    Tong, Jinhui, E-mail: jinhuitong@126.com [Key Laboratory of Eco-Environment-Related Polymer Materials, Ministry of Education (China); Key Laboratory of Gansu Polymer Materials, College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070 (China); Su, Lingdi [Key Laboratory of Eco-Environment-Related Polymer Materials, Ministry of Education (China); Key Laboratory of Gansu Polymer Materials, College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070 (China); Bo, Lili [College of Science, Gansu Agricultural University, Lanzhou 730070 (China); Cai, Xiaodong; Zhang, Qianping; Wang, Qizhao [Key Laboratory of Eco-Environment-Related Polymer Materials, Ministry of Education (China); Key Laboratory of Gansu Polymer Materials, College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070 (China)

    2016-01-15

    Highlights: • Mesoporous Cu–Pd ferrites were prepared by a facile, mild and environment-friendly route. • The catalysts have shown great efficiencies in Suzuki coupling reaction and up to 36.9 × 10{sup 3} h{sup −1} TOF can be obtained. • The catalyst can be magnetically separated easily and have shown prominent recyclability. - Abstract: Mesoporous Cu–Pd ferrites were prepared by using MCM-41 and SBA-15 mesoporous molecular sieves as hard templates and well characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), ICP-atomic emission spectroscopy, N{sub 2} adsorption–desorption and X-ray photoelectric spectroscopy (XPS). Compared with samples prepared by the sol–gel auto-combustion methods, the as-prepared mesoporous ferrites have shown uniform pore size and much higher specific surface areas. The samples showed a remarkably high activity in connection with the Suzuki coupling reaction, especially Cu{sub 0.99}Pd{sub 0.01}Fe{sub 2}O{sub 4} prepared by using MCM-41 as template obtained an excellent TOF as high as 36.9 × 10{sup 3} h{sup −1} and no obvious decrease in the activity was observed after ten consecutive runs.

  16. Mild oxidation of methane to methanol or acetic acid on supported isolated rhodium catalysts

    Science.gov (United States)

    Shan, Junjun; Li, Mengwei; Allard, Lawrence F.; Lee, Sungsik; Flytzani-Stephanopoulos, Maria

    2017-11-01

    An efficient and direct method of catalytic conversion of methane to liquid methanol and other oxygenates would be of considerable practical value. However, it remains an unsolved problem in catalysis, as typically it involves expensive or corrosive oxidants or reaction media that are not amenable to commercialization. Although methane can be directly converted to methanol using molecular oxygen under mild conditions in the gas phase, the process is either stoichiometric (and therefore requires a water extraction step) or is too slow and low-yielding to be practical. Methane could, in principle, also be transformed through direct oxidative carbonylation to acetic acid, which is commercially obtained through methane steam reforming, methanol synthesis, and subsequent methanol carbonylation on homogeneous catalysts. However, an effective catalyst for the direct carbonylation of methane to acetic acid, which might enable the economical small-scale utilization of natural gas that is currently flared or stranded, has not yet been reported. Here we show that mononuclear rhodium species, anchored on a zeolite or titanium dioxide support suspended in aqueous solution, catalyse the direct conversion of methane to methanol and acetic acid, using oxygen and carbon monoxide under mild conditions. We find that the two products form through independent pathways, which allows us to tune the conversion: three-hour-long batch-reactor tests conducted at 150 degrees Celsius, using either the zeolite-supported or the titanium-dioxide-supported catalyst, yield around 22,000 micromoles of acetic acid per gram of catalyst, or around 230 micromoles of methanol per gram of catalyst, respectively, with selectivities of 60–100 per cent. We anticipate that these unusually high activities, despite still being too low for commercial application, may guide the development of optimized catalysts and practical processes for the direct conversion of methane to methanol, acetic acid and other

  17. Mild oxidation of methane to methanol or acetic acid on supported isolated rhodium catalysts.

    Science.gov (United States)

    Shan, Junjun; Li, Mengwei; Allard, Lawrence F; Lee, Sungsik; Flytzani-Stephanopoulos, Maria

    2017-11-29

    An efficient and direct method of catalytic conversion of methane to liquid methanol and other oxygenates would be of considerable practical value. However, it remains an unsolved problem in catalysis, as typically it involves expensive or corrosive oxidants or reaction media that are not amenable to commercialization. Although methane can be directly converted to methanol using molecular oxygen under mild conditions in the gas phase, the process is either stoichiometric (and therefore requires a water extraction step) or is too slow and low-yielding to be practical. Methane could, in principle, also be transformed through direct oxidative carbonylation to acetic acid, which is commercially obtained through methane steam reforming, methanol synthesis, and subsequent methanol carbonylation on homogeneous catalysts. However, an effective catalyst for the direct carbonylation of methane to acetic acid, which might enable the economical small-scale utilization of natural gas that is currently flared or stranded, has not yet been reported. Here we show that mononuclear rhodium species, anchored on a zeolite or titanium dioxide support suspended in aqueous solution, catalyse the direct conversion of methane to methanol and acetic acid, using oxygen and carbon monoxide under mild conditions. We find that the two products form through independent pathways, which allows us to tune the conversion: three-hour-long batch-reactor tests conducted at 150 degrees Celsius, using either the zeolite-supported or the titanium-dioxide-supported catalyst, yield around 22,000 micromoles of acetic acid per gram of catalyst, or around 230 micromoles of methanol per gram of catalyst, respectively, with selectivities of 60-100 per cent. We anticipate that these unusually high activities, despite still being too low for commercial application, may guide the development of optimized catalysts and practical processes for the direct conversion of methane to methanol, acetic acid and other useful

  18. HDS, HDN and HDA activities of nickel-molybdenum catalysts supported on alumina

    Energy Technology Data Exchange (ETDEWEB)

    Dominguez-Crespo, M.A. [Instituto Mexicano del Petroleo, Programa de Tratamiento de Crudo Maya. Avenida Eje Central Lazaro Cardenas No.152, Col. San Bartolo Atepehuacan, 07730, Mexico D. F. (Mexico); Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada (CICATA-Altamira, IPN) Km 14.5 Carretera Tampico-puerto Industrial 89600, Altamira, Tamaulipas (Mexico); Torres-Huerta, A.M.; Ramirez-Meneses, E. [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada (CICATA-Altamira, IPN) Km 14.5 Carretera Tampico-puerto Industrial 89600, Altamira, Tamaulipas (Mexico); Diaz-Garcia, L. [Instituto Mexicano del Petroleo, Programa de Tratamiento de Crudo Maya. Avenida Eje Central Lazaro Cardenas No.152, Col. San Bartolo Atepehuacan, 07730, Mexico D. F. (Mexico); Arce-Estrada, E.M. [Instituto Politecnico Nacional, Departamento de Metalurgia y Materiales. A.P. 75-876, 07300 Mexico, D. F. (Mexico)

    2008-08-15

    In this work, NiMo-Al{sub 2}O{sub 3} catalysts were prepared by using different alumina precursors. The supports were impregnated by means of the spray at incipient wetness technique in both basic and acid media. Both the supports and fresh catalysts were characterized by the adsorption-desorption isotherms, Temperature-Programmed Reduction (TPR), Thermal Pyridine Adsorption-Desorption (TPD) and X-Ray Diffraction analyses (XRD). After sulfidation, the NiMoS metallic particles were characterized by Transmission Electron Microscopy (TEM). The initial analyses were performed in a trickle-bed reactor by using a real feedstock (Mexican heavy gas oil) and performing hydrotreating reactions (HDS, HDN and HDA) at three different temperatures: 613, 633 and 653 K; and 54 kg cm{sup -} {sup 2}. The catalytic activities are discussed in relation to the physicochemical properties of the NiMo catalysts, alumina phase and pH of the impregnating solution. The catalytic results show an increase in the conversion profiles with temperature. The sulfur conversion was increased from 89 to 99.25%, 91-99%, 90.8-97%, 83-95% and 78-96% when the crystal size of the support varied from 3 to 20 nm, respectively. The nitrogen and aromatic conversions were also increased in the range of 23-45 wt.%. It was found that the {gamma} phase reached a higher catalytic performance than the {eta} phase. The NiMo catalysts synthesized in a basic medium showed a better catalytic performance than that obtained with those prepared in acid solutions. The significance of the kinetic data to compare the catalysts is discussed. The maximum value of the catalytic activity was reached with the catalysts with the smallest particle sizes. (author)

  19. Supported Molybdenum Catalysts for the Deoxydehydration of 1,4-Anhydroerythritol into 2,5-Dihydrofuran.

    Science.gov (United States)

    Sandbrink, Lennart; Beckerle, Klaus; Meiners, Isabell; Liffmann, Rebecca; Rahimi, Khosrow; Okuda, Jun; Palkovits, Regina

    2017-04-10

    Efficient deoxygenation strategies are crucial for the valorization of renewable feedstocks. Deoxydehydration (DODH) enables the direct transformation of two adjacent hydroxyl groups into a double bond. Supported molybdenum-based catalysts were utilized for the first time in DODH. MoOx /TiO2 showed superior catalytic activity compared to common molybdenum salts. The catalyst efficiently converted 1,4-anhydroerythritol into 2,5-dihydrofuran in the presence of 3-octanol as reducing agent, showing high reproducibility and stability. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. An Alumina-Supported Ni-La-Based Catalyst for Producing Synthetic Natural Gas

    Directory of Open Access Journals (Sweden)

    Daniel E. Rivero-Mendoza

    2016-10-01

    Full Text Available LaNi5, known for its hydrogen storage capability, was adapted to the form of a metal oxide-supported (γ-Al2O3 catalyst and its performance for the Sabatier reaction assessed. The 20 wt % La-Ni/γ-Al2O3 particles were prepared via solution combustion synthesis (SCS and exhibited good catalytic activity, achieving a CO2 conversion of 75% with a high CH4 selectivity (98% at 1 atm and 300 °C. Characteristics of the La-Ni/γ-Al2O3 catalyst were identified at various stages of the catalytic process (as-prepared, activated, and post-reaction and in-situ DRIFTS was used to probe the reaction mechanism. The as-prepared catalyst contained amorphous surface La–Ni spinels with particle sizes <6 nm. The reduction process altered the catalyst make-up where, despite the reducing conditions, Ni2+-based particles with diameters between 4 and 20 nm decorated with LaOx moieties were produced. However, the post-reaction catalyst had particle sizes of 4–9 nm and comprised metallic Ni, with the LaOx decoration reverting to a form akin to the as-prepared catalyst. DRIFTS analysis indicated that formates and adsorbed CO species were present on the catalyst surface during the reaction, implying the reaction proceeded via a H2-assisted and sequential CO2 dissociation to C and O. These were then rapidly hydrogenated into CH4 and H2O.

  1. Bimetallic Pt-Ni catalysts supported on usy zeolite for n-hexane isomerization

    Directory of Open Access Journals (Sweden)

    F. V. Barsi

    2009-06-01

    Full Text Available Isomerization of linear alkanes has had considerable importance for the refining industry because the isomers formed in this reaction have high octane number. Most works reported in the literature studied the use of bifunctional catalysts, i.e., ones that have acid sites and metallic sites. In this study, bifunctional monometallic (Ni or Pt and bimetallic catalysts (Pt-Ni, using HUSY zeolite as the support, were prepared in order to verify the role of the metal content and composition on the catalytic properties for n-hexane isomerization. The method used for metal dispersion in the zeolite was competitive ion exchange using ammine complexes [Ni(NH36]Cl2 and [Pt(NH34]Cl2 as precursors. Four series of catalysts with constant atomic metal content had total metal amounts between 130 and 280 µmol M/g cat. Catalysts were characterized by temperature programmed reduction (TPR and subjected to catalytic evaluation for n-hexane isomerization at 250 ºC and 1 atm using H2/C6 = 9 molar ratio. TPR results show an easier reducibility of Ni+2 cations in the presence of Pt, which was evidenced by the displacement of the reduction peak of those cations towards lower temperatures in bimetallic catalysts. The bimetallic catalysts presented a higher activity in the isomerization of n-hexane when compared to the monometallic ones, as well better stability as the Pt content in the solid increases. The results of the activity as a function of the Pt content in the bimetallic catalysts show a maximum value around 50% of Pt. An addition of Pt above this critical value leads to a small decrease of the catalytic activity.

  2. Fundamental Studies of the Reforming of Oxygenated Compounds over Supported Metal Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Dumesic, James A. [Univ. of Wisconsin, Madison, WI (United States)

    2016-01-04

    The main objective of our research has been to elucidate fundamental concepts associated with controlling the activity, selectivity, and stability of bifunctional, metal-based heterogeneous catalysts for tandem reactions, such as liquid-phase conversion of oxygenated hydrocarbons derived from biomass. We have shown that bimetallic catalysts that combine a highly-reducible metal (e.g., platinum) with an oxygen-containing metal promoter (e.g., molybdenum) are promising materials for conversion of oxygenated hydrocarbons because of their high activity for selective cleavage for carbon-oxygen bonds. We have developed methods to stabilize metal nanoparticles against leaching and sintering under liquid-phase reaction conditions by using atomic layer deposition (ALD) to apply oxide overcoat layers. We have used controlled surface reactions to produce bimetallic catalysts with controlled particle size and controlled composition, with an important application being the selective conversion of biomass-derived molecules. The synthesis of catalysts by traditional methods may produce a wide distribution of metal particle sizes and compositions; and thus, results from spectroscopic and reactions kinetics measurements have contributions from a distribution of active sites, making it difficult to assess how the size and composition of the metal particles affect the nature of the surface, the active sites, and the catalytic behavior. Thus, we have developed methods to synthesize bimetallic nanoparticles with controlled particle size and controlled composition to achieve an effective link between characterization and reactivity, and between theory and experiment. We have also used ALD to modify supported metal catalysts by addition of promoters with atomic-level precision, to produce new bifunctional sites for selective catalytic transformations. We have used a variety of techniques to characterize the metal nanoparticles in our catalysts, including scanning transmission electron

  3. Niobia-supported Cobalt Catalysts for Fischer-Tropsch Synthesis

    NARCIS (Netherlands)

    den Otter, J.H.

    2016-01-01

    In this thesis niobia has been shown to be an attractive support for application in Fischer-Tropsch catalysis at industrially relevant conditions without apparent deactivation up to at least 200 hours of operation. This proves that the level of potentially poisoning contaminants is sufficiently low

  4. Zeolite supported palladium catalysts for hydroalkylation of phenolic model compounds

    Czech Academy of Sciences Publication Activity Database

    Akhmetzyanova, U.; Opanasenko, Maksym; Horáček, J.; Montanari, E.; Čejka, Jiří; Kikhtyanin, O.

    2017-01-01

    Roč. 252, NOV 2017 (2017), s. 116-124 ISSN 1387-1811 R&D Projects: GA ČR GBP106/12/G015 Institutional support: RVO:61388955 Keywords : Phenol hydroalkylation * Cyclohexylcyclohexane * MWW Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 3.615, year: 2016

  5. Recent Applications of Polymer Supported Organometallic Catalysts in Organic Synthesis

    Directory of Open Access Journals (Sweden)

    Nina Kann

    2010-09-01

    Full Text Available Recent developments concerning the application of polymer supported organometallic reagents in solid phase synthesis are reviewed, with a special focus on methodology for carbon-carbon formation. Examples of reactions that are covered include the classical Suzuki, Sonogashira and Heck coupings, but also aryl amination, epoxide opening, rearrangements, metathesis and cyclopropanation. Applications in the field of asymmetric synthesis are also discussed.

  6. Hydrodechlorination of Tetrachloromethane over Palladium Catalysts Supported on Mixed MgF2-MgO Carriers

    Directory of Open Access Journals (Sweden)

    Magdalena Bonarowska

    2016-11-01

    Full Text Available Pd/MgO, Pd/MgF2 and Pd/MgO-MgF2 catalysts were investigated in the reaction of CCl4 hydrodechlorination. All the catalysts deactivated in time on stream, but the degree of deactivation varied from catalyst to catalyst. The MgF2-supported palladium with relatively large metal particles appeared the best catalyst, characterized by good activity and selectivity to C2-C5 hydrocarbons. Investigation of post-reaction catalyst samples allowed to find several details associated with the working state of hydrodechlorination catalysts. The role of support acidity was quite complex. On the one hand, a definite, although not very high Lewis acidity of MgF2 is beneficial for shaping high activity of palladium catalysts. The MgO-MgF2 support characterized by stronger Lewis acidity than MgF2 contributes to very good catalytic activity for a relatively long reaction period (~5 h but subsequent neutralization of stronger acid centers (by coking eliminates them from the catalyst. On the other hand, the role of acidity evolution, which takes place when basic supports (like MgO are chlorided during HdCl reactions, is difficult to assess because different events associated with distribution of chlorided support species, leading to partial or even full blocking of the surface of palladium, which plays the role of active component in HdCl reactions.

  7. NiO-PTA supported on ZIF-8 as a highly effective catalyst for hydrocracking of Jatropha oil

    Science.gov (United States)

    Liu, Jing; He, Jing; Wang, Luying; Li, Rong; Chen, Pan; Rao, Xin; Deng, Lihong; Rong, Long; Lei, Jiandu

    2016-01-01

    Nickel oxide (NiO) and phosphotungstic acid (PTA) supported on a ZIF-8 (NiO-PTA/ZIF-8) catalyst was first synthesized and it showed high activity and good selectivity for the hydrocracking of Jatropha oil. The catalyst was characterized by SEM, SEM-EDS, TEM, N2 adsorption, FT-IR, XRD and XPS. Compared with the NiO-PTA/Al2O3 catalyst, the selectivity of C15-C18 hydrocarbon increased over 36%, and catalytic efficiency increased 10 times over the NiO-PTA/ZIF-8 catalyst. The prepared NiO-PTA/ZIF-8 catalyst was stable for a reaction time of 104 h and the kinetic behavior was also analyzed. This catalyst was found to bypass the presulfurization process, showing promise as an alternative to sulfided catalysts for green diesel production. PMID:27020579

  8. Development of a supported tri-metallic catalyst and evaluation of the catalytic activity in biomass steam gasification.

    Science.gov (United States)

    Li, Jianfen; Xiao, Bo; Yan, Rong; Xu, Xiaorong

    2009-11-01

    A supported tri-metallic catalyst (nano-Ni-La-Fe/gamma-Al(2)O(3)) was developed for tar reduction and enhanced hydrogen production in biomass steam gasification, with focuses on preventing coke deposition and sintering effects to lengthen the lifetime of developed catalysts. The catalyst was prepared by deposition-precipitation method and characterized by various analytical approaches. Following that, the activity of catalysts in biomass steam gasification was investigated in a bench-scale combined fixed bed reactor. With presence of the catalyst, the content of hydrogen in gas products was increased to over 10 vol.%, the tar removal efficiency reached 99% at 1073 K, and more importantly the coke deposition on the catalyst surfaces and sintering effects were avoided, leading to a long lifetime of catalysts.

  9. Highly efficient aerobic oxidation of alcohols by using less-hindered nitroxyl-radical/copper catalysis: optimum catalyst combinations and their substrate scope.

    Science.gov (United States)

    Sasano, Yusuke; Kogure, Naoki; Nishiyama, Tomohiro; Nagasawa, Shota; Iwabuchi, Yoshiharu

    2015-04-01

    The oxidation of alcohols into their corresponding carbonyl compounds is one of the most fundamental transformations in organic chemistry. In our recent report, 2-azaadamantane N-oxyl (AZADO)/copper catalysis promoted the highly chemoselective aerobic oxidation of unprotected amino alcohols into amino carbonyl compounds. Herein, we investigated the extension of the promising AZADO/copper-catalyzed aerobic oxidation of alcohols to other types of alcohol. During close optimization of the reaction conditions by using various alcohols, we found that the optimum combination of nitroxyl radical, copper salt, and solution concentration was dependent on the type of substrate. Various alcohols, including highly hindered and heteroatom-rich ones, were efficiently oxidized into their corresponding carbonyl compounds under mild conditions with lower amounts of the catalysts. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Alkaline ionic liquids applied in supported ionic liquid catalyst for selective hydrogenation of citral to citronellal

    Directory of Open Access Journals (Sweden)

    Eero eSalminen

    2014-02-01

    Full Text Available The challenge in preparation of ionic liquids containing a strong alkaline anion is to identify a suitable cation which can tolerate the harsh conditions induced by the anion. In this study, a commercial quaternary ammonium compound (quat benzalkonium [ADBA] (alkyldimethylbenzylammonium was used as a cation in the synthesis of different alkaline ionic liquids. In fact, the precursor, benzalkonium chloride, is a mixture of alkyldimethylbenzylammonium chlorides of various alkyl chain lengths and is commonly used in the formulation of various antiseptic products. The prepared ionic liquids were utilized as Supported Ionic Liquid Catalysts (SILCAs. Typically, a SILCA contains metal nanoparticles, enzymes or metal complexes in an ionic liquid layer which is immobilized on a solid carrier material such as an active carbon cloth (ACC. The catalysts were applied in the selective hydrogenation of citral to citronellal which is an important perfumery chemical. Interestingly, 70 % molar yield towards citronellal was achieved over a catalyst containing the alkaline ionic liquid benzalkonium methoxide.

  11. Alkaline ionic liquids applied in supported ionic liquid catalyst for selective hydrogenation of citral to citronellal

    Science.gov (United States)

    Salminen, Eero; Virtanen, Pasi; Mikkola, Jyri-Pekka

    2014-02-01

    The challenge in preparation of ionic liquids containing a strong alkaline anion is to identify a suitable cation which can tolerate the harsh conditions induced by the anion. In this study, a commercial quaternary ammonium compound (quat) benzalkonium [ADBA] (alkyldimethylbenzylammonium) was used as a cation in the synthesis of different alkaline ionic liquids. In fact, the precursor, benzalkonium chloride, is a mixture of alkyldimethylbenzylammonium chlorides of various alkyl chain lengths and is commonly used in the formulation of various antiseptic products. The prepared ionic liquids were utilized as Supported Ionic Liquid Catalysts (SILCAs). Typically, a SILCA contains metal nanoparticles, enzymes or metal complexes in an ionic liquid layer which is immobilized on a solid carrier material such as an active carbon cloth (ACC). The catalysts were applied in the selective hydrogenation of citral to citronellal which is an important perfumery chemical. Interestingly, 70 % molar yield towards citronellal was achieved over a catalyst containing the alkaline ionic liquid benzalkonium methoxide.

  12. Single-Atom Catalyst of Platinum Supported on Titanium Nitride for Selective Electrochemical Reactions.

    Science.gov (United States)

    Yang, Sungeun; Kim, Jiwhan; Tak, Young Joo; Soon, Aloysius; Lee, Hyunjoo

    2016-02-05

    As a catalyst, single-atom platinum may provide an ideal structure for platinum minimization. Herein, a single-atom catalyst of platinum supported on titanium nitride nanoparticles were successfully prepared with the aid of chlorine ligands. Unlike platinum nanoparticles, the single-atom active sites predominantly produced hydrogen peroxide in the electrochemical oxygen reduction with the highest mass activity reported so far. The electrocatalytic oxidation of small organic molecules, such as formic acid and methanol, also exhibited unique selectivity on the single-atom platinum catalyst. A lack of platinum ensemble sites changed the reaction pathway for the oxygen-reduction reaction toward a two-electron pathway and formic acid oxidation toward direct dehydrogenation, and also induced no activity for the methanol oxidation. This work demonstrates that single-atom platinum can be an efficient electrocatalyst with high mass activity and unique selectivity. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. High-Throughput Synthesis of Support Materials for Olefin Polymerization Catalyst.

    Science.gov (United States)

    Chammingkwan, Patchanee; Terano, Minoru; Taniike, Toshiaki

    2017-05-08

    Rational catalyst design necessitates fundamental knowledge on the structure-performance relationship, while the synthetic throughput for heterogeneous Ziegler-Natta olefin polymerization catalysts has long prevented the acquisition of a statistical database. In this contribution, an in-house reactor system was developed to realize the parallel synthesis of support materials for Ziegler-Natta catalysts for the first time. The developed system enabled parallel synthesis of 24 magnesium ethoxide samples with excellent reproducibility and morphological control comparable to a conventional experiment. Our demonstration revealed that the generation of diverse particle characteristics could be achieved through the addition of a third component as a structural modulator, in which the in-house parallel reactor system combined with the first principle component analysis enabled fast screening of effective modulators.

  14. Recent progress in solution plasma-synthesized-carbon-supported catalysts for energy conversion systems

    Science.gov (United States)

    Lun Li, Oi; Lee, Hoonseung; Ishizaki, Takahiro

    2018-01-01

    Carbon-based materials have been widely utilized as the electrode materials in energy conversion and storage technologies, such as fuel cells and metal–air batteries. In these systems, the oxygen reduction reaction is an important step that determines the overall performance. A novel synthesis route, named the solution plasma process, has been recently utilized to synthesize various types of metal-based and heteroatom-doped carbon catalysts. In this review, we summarize cutting-edge technologies involving the synthesis and modeling of carbon-supported catalysts synthesized via solution plasma process, followed by current progress on the electrocatalytic performance of these catalysts. This review provides the fundamental and state-of-the-art performance of solution-plasma-synthesized electrode materials, as well as the remaining scientific and technological challenges for this process.

  15. Biodiesel production in a membrane reactor using MCM-41 supported solid acid catalyst.

    Science.gov (United States)

    Xu, Wei; Gao, Lijing; Wang, Songcheng; Xiao, Guomin

    2014-05-01

    Production of biodiesel from the transesterification between soybean oil and methanol was conducted in this study by a membrane reactor, in which ceramic membrane was packed with MCM-41 supported p-toluenesulfonic acid (PTSA). Box-Behnken design and response surface methodology (RSM) were used to investigate the effects of reaction temperature, catalyst amount and circulation velocity on the yield of biodiesel. A reduced cubic model was developed to navigate the design space. Reaction temperature was found to have most significant effect on the biodiesel yield while the interaction of catalyst amount and circulation velocity have minor effect on it. 80°C of reaction temperature, 0.27 g/cm(3) of catalyst amount and 4.15 mL/min of circulation velocity were proved to be the optimum conditions to achieve the highest biodiesel yield. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Carbon-supported bimetallic Pd–Fe catalysts for vapor-phase hydrodeoxygenation of guaiacol

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-10-01

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

  17. Platinum nanoparticles supported on activated carbon fiber as catalyst for methanol oxidation

    Science.gov (United States)

    Huang, Hui Xing; Chen, Shui Xia; Yuan, Chan'e.

    Activated carbon fiber (ACF) with high specific surface area has been used as support in the preparation of Pt nanoparticles electrocatalyst (Pt/ACF) for direct alcohol fuel cells. It is found that the Pt nanoparticles on ACF are highly and homogeneously dispersed with a narrow size distribution in the range of 1.5-3.5 nm with an average size of 2.4 nm. In comparison with the commercial E-TEK Pt/C catalyst, the Pt/ACF catalyst exhibits much higher catalytic activity for methanol, ethanol and isopropanol oxidation, which are about 2.4 times as high as that of the former. The Pt/ACF catalyst is observed to be significantly more stable during the constant current density polarization and continuous cyclic voltammetry in comparison with Pt/C catalyst. Both the uniform dispersion of Pt nanoparticles and strong interactions between Pt nanoparticles and ACF are of benefit to achieve the performance improvement of Pt/ACF catalyst.

  18. Hydrogen generation from sodium borohydride solution using a ruthenium supported on graphite catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Yan; Dai, Hong-Bin; Ma, Lai-Peng; Wang, Ping; Cheng, Hui-Ming [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China)

    2010-04-15

    The catalyst with high activity and durability plays a crucial role in the hydrogen generation systems for the portable fuel cell generators. In the present study, a ruthenium supported on graphite catalyst (Ru/G) for hydrogen generation from sodium borohydride (NaBH{sub 4}) solution is prepared by a modified impregnation method. This is done by surface pretreatment with NH{sub 2} functionalization via silanization, followed by adsorption of Ru (III) ion onto the surface, and then reduced by a reducing agent. The obtained catalyst is characterized by transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS). Very uniform Ru nanoparticles with sizes of about 10 nm are chemically bonded on the graphite surface. The hydrolysis kinetics measurements show that the concentrations of NaBH{sub 4} and NaOH all exert considerable influence on the catalytic activity of Ru/G catalyst towards the hydrolysis reaction of NaBH{sub 4}. A hydrogen generation rate of 32.3 L min{sup -1} g{sup -1} (Ru) in a 10 wt.% NaBH{sub 4} + 5 wt.% NaOH solution has been achieved, which is comparable to other noble catalysts that have been reported. (author)

  19. Graphene-supported platinum catalyst prepared with ionomer as surfactant for anion exchange membrane fuel cells

    Science.gov (United States)

    Zeng, L.; Zhao, T. S.; An, L.; Zhao, G.; Yan, X. H.; Jung, C. Y.

    2015-02-01

    In this work, we have synthesized an ionomer-coated graphene-supported platinum catalyst for anion exchange membrane fuel cells. Unlike the common surfactant stabilized colloidal method, we employ a home-made anion exchange ionomer (AEI), namely quaternary ammonia poly (2, 6-dimethyl-1, 4-phenylene oxide) (QAPPO), as the surfactant. The AEI coated on reduced graphene oxide (rGO) surfaces serves as a stabilizer to anchor the platinum precursor on rGO surfaces due to electrostatic interactions. As a result, platinum nanoparticles (Pt NPs) can be easily deposited onto rGO surfaces with a uniform distribution. The remarkable feature of the present synthesis method is that the surfactant, the coated AEI, does not need to be removed from the catalyst, but serves as hydroxide-conductive paths in the catalyst layer, leading to enhanced triple phase boundaries. It is demonstrated that the use of the catalyst obtained with the present method enables a H2/O2 AEMFC to yield a peak power density of 264.8 mW cm-2 at 60 °C, which is 30% higher than that produced from the same fuel cell but with the use of the catalyst synthesized by the conventional synthesis method.

  20. Efficient method for the conversion of agricultural waste into sugar alcohols over supported bimetallic catalysts.

    Science.gov (United States)

    Tathod, Anup P; Dhepe, Paresh L

    2015-02-01

    Promoter effect of Sn in the PtSn/γ-Al2O3 (AL) and PtSn/C bimetallic catalysts is studied for the conversion of variety of substrates such as, C5 sugars (xylose, arabinose), C6 sugars (glucose, fructose, galactose), hemicelluloses (xylan, arabinogalactan), inulin and agricultural wastes (bagasse, rice husk, wheat straw) into sugar alcohols (sorbitol, mannitol, xylitol, arabitol, galactitol). In all the reactions, PtSn/AL showed enhanced yields of sugar alcohols by 1.5-3 times than Pt/AL. Compared to C, AL supported bimetallic catalysts showed prominent enhancement in the yields of sugar alcohols. Bimetallic catalysts characterized by X-ray diffraction study revealed the stability of catalyst and absence of alloy formation thereby indicating that Pt and Sn are present as individual particles in PtSn/AL. The TEM analysis also confirmed stability of the catalysts and XPS study disclosed formation of electron deficient Sn species which helps in polarizing carbonyl bond to achieve enhanced hydrogenation activity. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. The high performance of tungsten carbides/porous bamboo charcoals supported Pt catalysts for methanol electrooxidation

    Science.gov (United States)

    Ma, Chun-an; Xu, Chenbin; Shi, Meiqin; Song, Guanghui; Lang, Xiaoling

    2013-11-01

    In this paper, a kind of environmental friendly and cost-effective bamboo charcoal (BC) is used as catalyst support in DMFCs instead of carbon nanotubes (CNTs), which is toxic and expensive. After special treatments, we obtain a sponge-like three-dimensional (3D) BC, which can provide high specific surface area (1264.5 m2 g-1) and porous matrices. Then, tungsten carbide (WC) and Pt are loaded on the BCs with microwave-assisted technique and 3D structural Pt/WC/BCs electro-catalyst is finally fabricated. Subsequently, the catalyst is characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). In the further electrochemical investigation, it was found that Pt/WC/BCs catalyst has higher performance (2.76 mA cm-2) and better CO-tolerance for methanol oxidation compared with Pt/WC/CNTs and commercial Pt/C. Herein, we believe that the as-synthesized 3D Pt/WC/BCs catalyst has great promising application in DMFCs.

  2. Characterization of Copper-Manganese-Aluminum-Magnesium Mixed Oxyhydroxide and Oxide Catalysts for Redox Reactions

    Science.gov (United States)

    Baksi, Arnab; Cocke, David L.; Gomes, Andrew; Gossage, John; Riggs, Mark; Beall, Gary; McWhinney, Hylton

    Complex multi-metal catalysts require several stages in their preparation. These are: co-mixing, co-precipitation, milling and sol-gel, drying, dehydroxylation, and calcination and sometimes regeneration of the hydroxide by rehydration. These processes require thermal analysis (DTA, TGA, DSC) and accompanying off gas analysis, plus one or more of these: XRD, XPS, SEMEDS, FTIR and UV-VIS. In this study, hydrotalcite, hopcalite and mixed systems were prepared and guided by the above characterization techniques. The systems were initiated by mixing the chlorides or nitrates followed by hydrothermal treatments to produce the hydroxides which were further treated by washing, drying, and calcination. The thermal analysis was critical to guide the preparation through these stages and when combined with structural determination methods considerable understanding of their chemical and physical changes was obtained. The correlations between preparation and characterization will be discussed.

  3. Tetranuclear copper(ii)-Schiff-base complexes as active catalysts for oxidation of cyclohexane and toluene.

    Science.gov (United States)

    Roy, Partha; Manassero, Mario

    2010-02-14

    Three new Cu(ii) complexes, [Cu(4)(O)(L(n))(2)(CH(3)COO)(4)] where HL(1) = 4-methyl-2,6-bis(2-fluoroethyliminomethyl) phenol for complex , HL(2) = 4-methyl-2,6-bis(2-chloroethyliminomethyl) phenol for complex .0.25CH(3)CN and HL(3) = 4-methyl-2,6-bis(2-bromoethyliminomethyl) phenol for complex have been synthesized and characterized by elemental analysis, FTIR, UV-vis spectroscopy, and electrospray ionization mass spectroscopy. The structure of complex .0.25CH(3)CN has also been confirmed by single crystal X-ray diffraction analysis. These complexes have been found to be active catalysts for the oxidation of cyclohexane and toluene in the presence of hydrogen peroxide as the oxidant under mild conditions. Cyclohexane is oxidized to yield cyclohexanol and cyclohexanone, whereas toluene is oxidized to benzyl alcohol and benzaldehyde.

  4. Practical aerobic oxidations of alcohols and amines with homogeneous copper/TEMPO and related catalyst systems.

    Science.gov (United States)

    Ryland, Bradford L; Stahl, Shannon S

    2014-08-18

    Oxidations of alcohols and amines are common reactions in the synthesis of organic molecules in the laboratory and industry. 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. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Inhibition effects in the partial oxidation of cyclohexane on polymer supported Co(II catalysts

    Directory of Open Access Journals (Sweden)

    MAJA ODOVIC

    2005-02-01

    Full Text Available Polymer supported catalysts with different contents of metal ions where synthesized by wet impregnation of the degassed support from ethanolic solutions of cobalt(II nitrate. Amacroreticular copolymer of poly-4-vinylpyridine with divinylbenzene was used as the support. The prepared catalysts were tested in the partial oxidation of cyclohexane to cyclohexanol and cyclohexanone. Activity tests were performed in a stainless steel, laboratory scale, stirred autoclave, in the semi batch regime under isothermal and non-isothermal conditions. Isothermal experiments where performed at 170 °C for 120 min. In the non-isothermal conditions. isothermal experiments where performed at 170 °C for 120 min. In the non-isothermal experiments, a constant heating rate of 0.3 degree/min was used in the range between 110 °C and 170 °C. Non-linear, least-squares analysis with the simplex optimization method and numerical simulation of the reaction model in each iterative step was used for the kinetic characterization of the process in a non-stationary, semi-batch regime. Apparent rate constants were obtained as an invariant measure of the catalytic system. Anon-linear effect of the content of metal ions on the reaction rate and on the ratio of the yield of the products was observed, which is attributed to a complex interactions between the reaction medium and the heterogeneous catalyst, including a catalyst-inhibition effect.

  6. Effect of cooling condition on chemical vapor deposition synthesis of graphene on copper catalyst.

    Science.gov (United States)

    Choi, Dong Soo; Kim, Keun Soo; Kim, Hyeongkeun; Kim, Yena; Kim, TaeYoung; Rhy, Se-hyun; Yang, Cheol-Min; Yoon, Dae Ho; Yang, Woo Seok

    2014-11-26

    Here, we show that chemical vapor deposition growth of graphene on copper foil is strongly affected by the cooling conditions. Variation of cooling conditions such as cooling rate and hydrocarbon concentration in the cooling step has yielded graphene islands with different sizes, density of nuclei, and growth rates. The nucleation site density on Cu substrate is greatly reduced when the fast cooling condition was applied, while continuing methane flow during the cooling step also influences the nucleation and growth rate. Raman spectra indicate that the graphene synthesized under fast cooling condition and methane flow on cool-down exhibit superior quality of graphene. Further studies suggest that careful control of the cooling rate and CH4 gas flow on the cooling step yield a high quality of graphene.

  7. Mesoporous Silica Supported Au Nanoparticles with Controlled Size as Efficient Heterogeneous Catalyst for Aerobic Oxidation of Alcohols

    Directory of Open Access Journals (Sweden)

    Xuefeng Chu

    2015-01-01

    Full Text Available A series of Au catalysts with different sizes were synthesized and employed on amine group functionalized ordered mesoporous silica solid supports as catalyst for the aerobic oxidation of various alcohols. The mesoporous silica of MCM-41 supported Au nanoparticles (Au-1 exhibited the smallest particle size at ~1.8 nm with superior catalytic activities owing to the confinement effect of the mesoporous channels. Au-1 catalyst is also very stable and reusable under aerobic condition. Therefore, this presented work would obviously provide us a platform for synthesizing more size-controlled metal catalysts to improve the catalytic performances.

  8. A facile method for the preparation of Covalent Triazine Framework coated monoliths as catalyst support - applications in C1 catalysis

    KAUST Repository

    Bavykina, Anastasiya V.

    2017-07-17

    A quasi Chemical Vapour Deposition method for the manufacturing of well-defined Covalent Triazine Framework (CTF) coatings on cordierite monoliths is reported. The resulting supported porous organic polymer is an excellent support for the immobilisation of two different homogeneous catalysts: 1) an IrIIICp*-based catalyst for the hydrogen production from formic acid, and 2) a PtII-based for the direct activation of methane via Periana chemistry. The immobilised catalysts display a much higher activity in comparison with the unsupported CTF operated in slurry because of improved mass transport. Our results demonstrate that CTF based catalysts can be further optimised by engineering at different length-scales.

  9. Copper-zinc alloy nanopowder: a robust precious-metal-free catalyst for the conversion of 5-hydroxymethylfurfural.

    Science.gov (United States)

    Bottari, Giovanni; Kumalaputri, Angela J; Krawczyk, Krzysztof K; Feringa, Ben L; Heeres, Hero J; Barta, Katalin

    2015-04-24

    Noble-metal-free copper-zinc nanoalloy (<150 nm) is found to be uniquely suited for the highly selective catalytic conversion of 5-hydroxymethylfurfural (HMF) to potential biofuels or chemical building blocks. Clean mixtures of 2,5-dimethylfuran (DMF) and 2,5-dimethyltetrahydrofuran (DMTHF) with combined product yields up to 97 % were obtained at 200-220 °C using 20-30 bar H2 . It is also possible to convert 10 wt % HMF solutions in CPME, with an excellent DMF yield of 90 %. Milder temperatures favor selective (95 %) formation of 2,5-furandimethanol (FDM). The one-pot conversion of fructose to valuable furan-ethers was also explored. Recycling experiments for DMF production show remarkable catalyst stability. Transmission electron microscopy (TEM) characterization provides more insight into morphological changes of this intriguing class of materials during catalysis. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. An Efficient and Recyclable Nanoparticle-Supported Cobalt Catalyst for Quinoxaline Synthesis

    Directory of Open Access Journals (Sweden)

    Fatemeh Rajabi

    2015-11-01

    Full Text Available The syntheses of quinoxalines derived from 1,2-diamine and 1,2-dicarbonyl compounds under mild reaction conditions was carried out using a nanoparticle-supported cobalt catalyst. The supported nanocatalyst exhibited excellent activity and stability and it could be reused for at least ten times without any loss of activity. No cobalt contamination could be detected in the products by AAS measurements, pointing to the excellent activity and stability of the Co nanomaterial.

  11. In Situ Raman Spectroscopy of Supported Chromium Oxide Catalysts: Reactivity Studies with Methanol and Butane

    NARCIS (Netherlands)

    Weckhuysen, B.M.; Wachs, I.E.

    1996-01-01

    The interactions of methanol and butane with supported chromium oxide catalysts under oxidizing and reducing conditions were studied by in situ Raman spectroscopy as a function of the specific oxide support (Al2O3, ZrO2, TiO2, SiO2, Nb2O5, 3% SiO2/TiO2, 3% TiO2/SiO2, and a physical mixture of SiO2

  12. Metal?Organic Framework Supported Cobalt Catalysts for the Oxidative Dehydrogenation of Propane at Low Temperature

    OpenAIRE

    Li, Zhanyong; Peters, Aaron W.; Bernales, Varinia; Ortu?o, Manuel A; Schweitzer, Neil M.; Destefano, Matthew R.; Gallington, Leighanne C; Platero-Prats, Ana E.; Chapman, Karena W; Cramer, Christopher J.; Gagliardi, Laura; Hupp, Joseph T.; Farha, Omar K.

    2016-01-01

    Zr-based metal?organic frameworks (MOFs) have been shown to be excellent catalyst supports in heterogeneous catalysis due to their exceptional stability. Additionally, their crystalline nature affords the opportunity for molecular level characterization of both the support and the catalytically active site, facilitating mechanistic investigations of the catalytic process. We describe herein the installation of Co(II) ions to the Zr6 nodes of the mesoporous MOF, NU-1000, via two distinct route...

  13. Healthy cities as catalysts for caring and supportive environments.

    Science.gov (United States)

    Green, Geoff; Jackisch, Josephine; Zamaro, Gianna

    2015-06-01

    'Caring and Supportive Environments' are fundamental to a social model of health and were a core theme of Phase V (2009-13) of the WHO European Healthy Cities Network. Deploying the methodology of realist evaluation, this article synthesizes qualitative evidence from 112 highly structured case studies from 68 Network cities and 71 responses to a General Evaluation Questionnaire, which asked cities to analyze city attributes and trends. A schematic model was developed to describe the interaction between action targeted toward children, migrants, older people and action on social and health services, health literacy and active citizenship-the six subtopics clustered within the theme Caring and Supportive Environments. Four hypotheses were tested: (i) there are prerequisites and processes of local governance that increase city capacity for creating supportive environments; (ii) investing in health and social services, active citizenship and health literacy enhance the social inclusion of vulnerable population groups; (iii) there are synergies between social investment and healthy urban planning; and (iv) these investments promote greater equity in health. The evaluation revealed many innovative practices. Providers of health and social services have developed partnerships with agencies influencing wider determinants of health. Health literacy campaigns address the wider context of people's lives. In a period of economic austerity, cities have utilized the social assets of their citizens. Realist evaluation can help illuminate the pathways from case study interventions to health outcomes, and the prerequisites and processes required to initiate and sustain such investments. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  14. Gold Functionalized Supported Ionic Liquids Catalyst for CO Oxidation

    Directory of Open Access Journals (Sweden)

    Svetlana Ivanova

    2011-11-01

    Full Text Available The present study tries to give an insight to the combination of the homogeneous and heterogeneous catalytic properties in a new class of materials. Well dispersed gold nanoparticles on an ionic liquid layer supported on a mineral carrier have been prepared. This work is concentrated on the characterizations and understanding of the interactions between all the components of the catalytic system. The application of the materials in the reaction of oxidation of carbon monoxide shows rather unexpected results—a good catalytic activity completely independent of the temperature.

  15. Electrooxidation of ethanol on novel multi-walled carbon nanotube supported platinum-antimony tin oxide nanoparticle catalysts

    Science.gov (United States)

    Guo, Dao-Jun

    We synthesize the new Pt based catalyst for direct ethanol fuel cells using novel multi-walled carbon nanotubes supported platinum-antimony tin oxide (Pt-ATO/MWCNT) nanoparticle as new catalyst support for the first time. The structure of Pt-ATO/MWCNT catalyst is characterized by transmission electron micrograph (TEM) and X-ray diffraction (XRD). The electrocatalytic properties of Pt-ATO/MWCNT catalyst for ethanol electrooxidation reactions are investigated by cyclic voltammetry (CV) and chronoamperometric experiments in acidic medium. The electrocatalytic activity for ethanol electrooxidation reaction shows that high carbon monoxide tolerance and good stability of Pt-ATO/MWCNT catalyst compared with Pt-SnO 2/MWCNT and commercial Pt/C are observed. These results imply that Pt-ATO/MWCNT catalyst has promising potential applications in direct alcohol fuel cells.

  16. The Use of Palladium on Magnetic Support as Catalyst for Suzuki–Miyaura Cross-Coupling Reactions

    Directory of Open Access Journals (Sweden)

    Magne O. Sydnes

    2017-01-01

    Full Text Available The development of new solid supports for palladium has received a lot of interest lately. These catalysts have been tested in a range of cross-coupling reactions, such as Suzuki–Miyaura, Mizoroki-Heck, and Sonogashira cross-coupling reactions, with good outcomes. Attaching the catalyst to a solid support simplifies the operations required in order to isolate and recycle the catalyst after a reaction has completed. Palladium on solid supports made of magnetic materials is particularly interesting since such catalysts can be removed very simply by utilizing an external magnet, which withholds the catalyst in the reaction vessel. This review will showcase some of the latest magnetic solid supports for palladium and highlight these catalysts’ performance in Suzuki–Miyaura cross-coupling reactions.

  17. The role of the oxidic support on the deactivation of Pt catalysts during the CO2 reforming of methane

    NARCIS (Netherlands)

    Bitter, J.H.; Hally, W.; Seshan, K.; Ommen, J.G. van; Lercher, J.A.

    1996-01-01

    Pt supported on y-Al2O3, TiO2 and ZrO2 are active catalysts for the CO2 reforming of methane to synthesis gas. The stability of the catalysts increased in the order Pt / y-Al2O3 < Pt / TiO2 < Pt / ZrO2. For all catalysts, the decrease in activity with time on stream is caused by carbon formation,

  18. Synthesis of Magnetic Carbon Supported Manganese Catalysts for Phenol Oxidation by Activation of Peroxymonosulfate

    Directory of Open Access Journals (Sweden)

    Yuxian Wang

    2016-12-01

    Full Text Available Magnetic core/shell nanospheres (MCS were synthesized by a novel and facile one-step hydrothermal method. Supported manganese oxide nanoparticles (Fe3O4/C/Mn were obtained from various methods (including redox, hydrothermal and impregnation using MCS as the support material and potassium permanganate as the precursor of manganese oxide. The Mn/MCS catalysts were characterized by a variety of characterization techniques and the catalytic performances of Fe3O4/C/Mn nanoparticles were tested in activation of peroxymonosulfate to produce reactive radicals for phenol degradation in aqueous solutions. It was found that Fe3O4/C/Mn catalysts can be well dispersed and easily separated from the aqueous solutions by an external magnetic field. Kinetic analysis showed that phenol degradation on Fe3O4/C/Mn catalysts follows the first order kinetics. The peroxymonosulfate activation mechanism by Fe3O4/C/Mn catalysts for phenol degradation was then discussed.

  19. Vapor Phase Hydrogenation of Nitrobenzene to Aniline Over Carbon Supported Ruthenium Catalysts.

    Science.gov (United States)

    Srikanth, Chakravartula S; Kumar, Vanama Pavan; Viswanadham, Balaga; Srikanth, Amirineni; Chary, Komandur V R

    2015-07-01

    A series of Ru/Carbon catalysts (0.5-6.0 wt%) were prepared by impregnation method. The catalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), temperature programmed reduction (TPR), X-ray photoelectron spectroscopy (XPS), CO-chemisorption, surface area and pore-size distribution measurements. The catalytic activities were evaluated for the vapor phase hydrogenation of nitrobenzene. The dispersion measured by CO-uptake values suggests that a decrease of dispersion is observed with increasing Ru loading on carbon support. These findings are well supported by the crystallite size measured from XRD measurements. XPS study reveals the formation of Ru0 after reduction at 573 K for 3 h. The catalysts exhibit high conversion/selectivity at 4.5 wt% Ru loading during hydrogenation reaction. The particle size measured from CO-chemisorption and TEM analysis are related to the TOF during the hydrogenation reaction. Ru/C catalysts are found to show higher conversion/selectivities during hydrogenation of nitrobenzene to aniline.

  20. Altervalent cation-doped MCM-41 supported palladium catalysts and their catalytic properties

    Directory of Open Access Journals (Sweden)

    HAIHUI JIANG

    2011-06-01

    Full Text Available Metal cation-doped MCM-41 (M-MCM-41, M = Al, Ce, Co, V or Zr supported Pd catalysts (Pd/M-MCM-41 were prepared by a solution-based reduction method. The catalysts were characterized by X-ray diffraction (XRD analysis, infrared spectroscopy (IR, scanning electron microscopy (SEM and transmission electron microscopy (TEM, and further evaluated by selective hydrogenation of para-chloronitrobenzene (p-CNB in anhydrous ethanol. The metal cation-containing Pd catalysts can efficiently enhance the selectivity for para-chloroaniline (p-CAN. The highest selectivity of 96.5 % in the molar distribution for p-CNB to p-CAN was acquired over Pd (1.8 wt. %/V-MCM-41 (Si/V = 30, molar ratio catalyst, and the corresponding turnover frequency (TOF was 1.24×10-2 mol p-CNB mol-1 Pd s-1. Water molecules adsorbed by the support have important effects on both the catalytic activity of the sample and the selectivity for p-CAN. A water molecule-mediated catalytic hydrogenation is discussed.

  1. Electrochemical oxidation of ethanol in acid media on titanium nitride supported fuel cell catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Thotiyl, M.M. Ottakam [Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore, Karnataka 560012 (India); Sampath, S., E-mail: sampath@ipc.iisc.ernet.i [Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore, Karnataka 560012 (India)

    2011-04-01

    In the present study, titanium nitride, TiN that possesses good electronic conductivity, high corrosion resistance combined with the ability to support metallic particles, has been used to anchor Pt catalysts and subsequently used for ethanol oxidation. Platinum deposited on TiN (Pt-TiN) surface is contrasted with the conventional support material, Vulcan carbon for the electrochemical oxidation of ethanol in acidic medium. Though the comparison is not straight forward due to different morphology/particle size of the Pt catalyst on the two supports, the present investigations reveal that the TiN support lead to surface Ti-OH type functional groups that help in reducing the accumulation of carbon monoxide on the catalyst surface. The Tafel slopes are similar but the exchange current density on Pt-TiN is approximately twice that of the value observed on Pt-C. X-ray photoelectron spectroscopy data support the long term stability and electrocatalytic activity of Pt-TiN electrocatalyst.

  2. A Brief Review of Carbon Dioxide Hydrogenation to Methanol Over Copper and Iron Based Catalysts

    Directory of Open Access Journals (Sweden)

    Tursunov Obid

    2017-09-01

    Full Text Available Climate change and global warming have become a challenging issue affecting not only humanity but also flora and fauna due to an intense increase of CO2 emission in the atmosphere which has gradually led to amplification in the average global temperature. Hence, a number of mechanisms have been promoted to diminish the atmospheric commutation of carbon dioxide. One of the well-known techniques is Carbon Capture and Storage (CCS which mechanism is based on capture and storage vast quantities of CO2, as well as Carbon Capture and Utilization (CCU which mechanism is based on CO2 conversion to liquid fuels (e.g. methanol, hydrocarbons, dimethyl carbonate, propylene, dimethyl ether, ethylene, etc.. Particularly, methanol (CH3OH is a key feedstock for industrial chemicals, which further can be converted into high molecular alternative liquid fuels. In this regard, hydrogenation of CO2 is one of the promising, effectual and economic techniques for utilization of CO2 emission. Nevertheless, the reduction/activation of CO2 into useful liquid products is a scientifically challenging issue due to the complexities associated with its high stability. Thus, various catalysts have been applied to reduce the activation energy of the hydrogenation process and transform CO2 into value-added products. Thereby, this review article highlights the progress and the recent advances of research investigation in Cu and Fe-based catalytic conversion of CO2, reaction mechanisms, catalytic reactivity, and influence of operating parameters on product efficiency.

  3. Study of Alginate-Supported Ionic Liquid and Pd Catalysts

    Directory of Open Access Journals (Sweden)

    Eric Guibal

    2012-01-01

    Full Text Available New catalytic materials, based on palladium immobilized in ionic liquid supported on alginate, were elaborated. Alginate was associated with gelatin for the immobilization of ionic liquids (ILs and the binding of palladium. These catalytic materials were designed in the form of highly porous monoliths (HPMs, in order to be used in a column reactor. The catalytic materials were tested for the hydrogenation of 4-nitroaniline (4-NA in the presence of formic acid as hydrogen donor. The different parameters for the elaboration of the catalytic materials were studied and their impact analyzed in terms of microstructures, palladium sorption properties and catalytic performances. The characteristics of the biopolymer (proportion of β-D-mannuronic acid (M and α-L-guluronic acid (G in the biopolymer defined by the M/G ratio, the concentration of the porogen agent, and the type of coagulating agent significantly influenced catalytic performances. The freezing temperature had a significant impact on structural properties, but hardly affected the catalytic rate. Cellulose fibers were incorporated as mechanical strengthener into the catalytic materials, and allowed to enhance mechanical properties and catalytic efficiency but required increasing the amount of hydrogen donor for catalysis.

  4. Copper modified TiO2 catalysts: application to nitrobenzenes degradation

    Directory of Open Access Journals (Sweden)

    Chunyu Shui

    2016-01-01

    Full Text Available Copper doped TiO2 by the method of sol-gel preparation was conducted to stimulate the TiO2 visible light response and enhance the performance of photocatalytic degradation. By XRD, SEM and EDS analysis, molar ratio of 1.0%, 1.5%, 2.0% and 1.0% Cu doped TiO2 presented smaller grain sizes (20-50 nm than German P25 TiO2 (50-100 nm. Especially, 1.5% Cu doped TiO2 presented the highest and finest degree of crystallinity from XRD peak. Its reunion phenomenon was the weakest among all Cu doped TiO2. Combined with Cu doping structure, micro stress changes as well as the performance of the degradation of nitrobenzenes (NBs, the optimum mol ratio of Cu doped TiO2 was 1.5%. With 1.5% Cu doped TiO2 for 180 min UV light degradation of NBs, the removal efficiency was 60.02%, two times higher than that of Germany P25 TiO2. The reaction of NBs photocatalytic degradation by CuxTi(1-xO2 followed first order kinetics. Synthetically, SEM, ESD and performances of NBs degradation confirmed that the optimal formula of CuxTi(1-xO2 for degradation of NBs was Cu0.0183Ti0.9817O2.

  5. Copper recovery in a bench-scale carrier facilitated tubular supported liquid membrane system

    Directory of Open Access Journals (Sweden)

    Makaka S.

    2010-01-01

    Full Text Available The extraction of copper ions in a tubular supported liquid membrane using LIX 984NC as a mobile carrier was studied, evaluating the effect of the feed characteristics (flowrate, density, viscosity on the feedside laminar layer of the membrane. A vertical countercurrent, double pipe perspex benchscale reactor consisting of a single hydrophobic PVDF tubular membrane mounted inside was used in all test work. The membrane was impregnated with LIX 984NC and became the support for this organic transport medium. Dilute Copper solution passed through the centre pipe and sulphuric acid as strippant passed through the shell side. Copper was successfully transported from the feedside to the stripside and from the data obtained, a relationship between Schmidt, Reynolds and Sherwood number was achieved of.

  6. Application of Cement Clinker as Ni-Catalyst Support for Glycerol Dry Reforming

    Directory of Open Access Journals (Sweden)

    Hua Chyn Lee

    2013-12-01

    Full Text Available The increase in biodiesel production inevitably yield plethora of glycerol. Therefore, glycerol has been touted as the most promising source for bio-syngas (mixture of H2 and CO production. Significantly, coking on nickel-based catalysts has been identified as a major deactivation factor in reforming technology. Indeed, coke-resistant catalyst development is essential to enhance syngas production. The current work develops cement clinker (comprised of 62.0% calcium oxide-supported nickel catalyst (with metal loadings of 5, 10, 15 and 20 wt% for glycerol dry reforming (CO2. Physicochemical characterization of the catalysts was performed using XRD, XRF, BET, TGA and FESEM-EDS techniques. Subsequently, reaction studies were conducted in a 7-mm ID fixed-bed stainless steel reactor at 1023 K with various CO2 partial pressures at constant weight-hourly space velocity (WHSV of 7.2×104 ml gcat-1 h-1. Gas compositions were determined using Agilent 3000 micro-gas chromatography (GC and Lancom III gas analyzer. Results obtained showed an increment of BET surface area up to 32-fold with Ni loading which was corroborated by FESEM images. Syngas (H2 and CO ratios of less than 2 were being produced at 1023 K. A closer scrutiny to the transient profile revealed that the presence of CO2 higher or lower than CGR 1:1 promotes the Boudouard reaction. © 2013 BCREC UNDIP. All rights reservedReceived: 30th May 2013; Revised: 27th August 2013; Accepted: 11st September 2013[How to Cite: Lee, H.C., Siew, W.K., Cheng, C.K. (2013. Preparation Application of Cement Clinker as Ni-Catalyst Support for Glycerol Dry Reforming. Bulletin of Chemical Reaction Engineering & Catalysis, 8 (2: 137-144. (doi:10.9767/bcrec.8.2.5023.137-144][Permalink/DOI: http://dx.doi.org/10.9767/bcrec.8.2.5023.137-144

  7. Preparation of Spent Bleaching Earth-supported Calcium From Limestone as Catalyst in Transesterification of Waste Frying Oil

    OpenAIRE

    Hindryawati, Noor; Daniel, Daniel; Erwin, Erwin; Maniam, Gaanty Pragas

    2017-01-01

    An investigation was conducted on palm oil refinery waste-spent bleaching earth (POR-SBE), POR-SBE supported by calcium as catalysts for methyl esters production through transesterification process using waste frying oil. The catalysts showed longer lasting activity than the traditional alkali catalysts. The optimum conditions for the process were: Ca-POR-SBE catalyst amount 7 %; methanol to oil molar ratio 12:1; and a reaction duration is 4 h. The process was able to transesterify oil to met...

  8. Natural phosphate-supported palladium: A highly efficient and recyclable catalyst for the suzuki-miyaura coupling under microwave irradiation

    KAUST Repository

    Hassine, Ayoub

    2015-01-19

    This report explores Suzuki-Miyaura coupling under microwave irradiation, using a new generation of catalyst that is based on natural phosphate (NP) impregnated by palladium. This catalyst was prepared by the treatment of natural phosphate with bis(benzonitrile)palladium(II) chloride in acetone at room temperature. The catalyst displayed high catalytic activity for the Suzuki-Miyaura coupling of aryl bromides and chlorides with aryl boronic acids in pure water and with the use of microwave irradiation. The low-cost and availability of the solid support, mild reaction conditions, high yields of desired products, recyclability of the catalyst and short reaction times are the notable features of these methods.

  9. Atomic structure of graphene supported heterogeneous model catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Franz, Dirk

    2017-04-15

    , whereupon the Ir clusters show equal ratio of ABC and ACB stacking. Pt/Rh clusters show mainly (∝75 %) ABC stacking and Ir/Pd clusters show exclusively ABC stacking - note the Ir(111) substrate stacking is chosen to be ABC-like. During gas exposure the clusters gain in height, while simultaneously the ordering of the cluster lattice decreases. The order of ACB stacked Pt/Rh clusters decreases more rapidly, so that a weakening of the cluster binding due to ACB stacking is proposed. In addition a size reduction of the lowest cluster layer to a hexagonal arrangement of 19 atoms was observed, which seems to be the energetically favoured interface area between graphene/Ir(111) and the investigated metal clusters. Platinum clusters containing fewer than 40 atoms have been investigated with surface sensitive X-ray diffraction. The cluster height could be determined and a reduced atom distance among the cluster was observed. CO exposure decreased the in-plane atom distance even more. This effect could be reverted by a subsequent oxygen exposure (2CO + O{sub 2} → 2 CO{sub 2}). For Pt/Rh clusters with fewer than 60 atoms the element distribution was investigated and revealed an enrichment of Rh at the two topmost cluster layers. This element distribution was found for co-deposition and sequential deposition of the material and is therefore independent of the order of deposition. Oxygen exposure led to the formation of a rhodium surface oxide, which could be prevented by preceding CO exposure. In case of Ir/Pd clusters containing ∝60 atoms we found preferences for a core/shell structure with iridium atoms at core sites. Exposure to p(H{sub 2})=1 bar did not result in the formation of the palladium β-phase, so that a reduced hydrogen solubility of graphene/Ir(111) supported palladium clusters is assumed. The reduced hydrogen solubility is probably a consequence of substrate induced strain among the cluster atoms.

  10. Hydrogen Production by Steam Reforming of Ethanol over Nickel Catalysts Supported on Sol Gel Made Alumina: Influence of Calcination Temperature on Supports.

    Science.gov (United States)

    Yaakob, Zahira; Bshish, Ahmed; Ebshish, Ali; Tasirin, Siti Masrinda; Alhasan, Fatah H

    2013-05-30

    Selecting a proper support in the catalyst system plays an important role in hydrogen production via ethanol steam reforming. In this study, sol gel made alumina supports prepared for nickel (Ni) catalysts were calcined at different temperatures. A series of (Ni/AlS.G.) catalysts were synthesized by an impregnation procedure. The influence of varying the calcination temperature of the sol gel made supports on catalyst activity was tested in ethanol reforming reaction. The characteristics of the sol gel alumina supports and Ni catalysts were affected by the calcination temperature of the supports. The structure of the sol gel made alumina supports was transformed in the order of γ → (γ + θ) → θ-alumina as the calcination temperature of the supports increased from 600 °C to 1000 °C. Both hydrogen yield and ethanol conversion presented a volcano-shaped behavior with maximum values of 4.3 mol/mol ethanol fed and 99.5%, respectively. The optimum values were exhibited over Ni/AlS.G800 (Ni catalyst supported on sol gel made alumina calcined at 800 °C). The high performance of the Ni/AlS.G800 catalyst may be attributed to the strong interaction of Ni species and sol gel made alumina which lead to high nickel dispersion and small particle size.

  11. Dynamic Cu/Zn interaction in SiO2 supported methanol synthesis catalysts unravelled by in situ XAFS

    NARCIS (Netherlands)

    Grandjean, D.P.P.; Pelipenko, V.; Batyrev, E.D.; van den Heuvel, J.C.; Khassin, A.A.; Yurieva, T.M.; Weckhuysen, B.M.

    2011-01-01

    In situ X-ray absorption spectroscopy XAFS at the Cu and Zn K-edge has been used to unravel the Cu/Zn interaction and identify the possible active site of Cu-based methanol synthesis catalysts in the Cu/ZnO/SiO2 ternary system. These highly dispersed silica supported catalysts, whose activity

  12. Titania Supported Pt and Pt/Pd Nano-particle Catalysts for the Oxidation of Sulfur Dioxide

    DEFF Research Database (Denmark)

    Koutsopoulos, Sotiris; Johannessen, Tue; Eriksen, Kim Michael

    2006-01-01

    Several types of titania (anatase) were used as supports for pure platinum and Pt–Pd bimetallic alloy catalysts. The preparation methods, normal wet impregnation technique and flame aerosol synthesis, obtained metal loadings of 2% by weight. The prepared catalysts were tested for SO2 oxidation ac...

  13. Oxidation of o-xylene on mesoporous Ti-phosphate-supported VOx catalysts and promoter effect of K+ on selectivity

    NARCIS (Netherlands)

    Mérida-Robles, J.; Rodríguez-Castellón, E.; Jiménez-López, A.; López Granados, M.; Val, S. del; Melián Cabrera, I.; Fierro, J.L.G.; Jimenez, J

    2005-01-01

    The selective oxidation of o-xylene on catalysts based on mesoporous titanium phosphate-supported vanadium oxide has been studied. The catalysts were characterized by different physico-chemical techniques (XRD, XPS, N-2 isotherms, TPD of chemisorbed NH3 and Raman spectroscopy). The conversion and

  14. Effects of loading and synthesis method of titania-supported cobalt catalysts for Fischer–Tropsch synthesis

    NARCIS (Netherlands)

    Eschemann, T.O.; Bitter, J.H.; Jong, de K.P.

    2014-01-01

    Because of their high activity and selectivity to C5+ hydrocarbons in the Fischer–Tropsch, process, titania-supported cobalt catalysts have received great interest from industrial and academic, institutions. Here, we report on three catalyst preparation procedures, incipient wetness impregnation

  15. Effects of loading and synthesis method of titania-supported cobalt catalysts for Fischer-Tropsch synthesis

    NARCIS (Netherlands)

    Eschemann, Thomas O.|info:eu-repo/dai/nl/33082712X; Bitter, Johannes H.|info:eu-repo/dai/nl/160581435; De Jong, Krijn P.|info:eu-repo/dai/nl/06885580X

    2014-01-01

    Because of their high activity and selectivity to C5+ hydrocarbons in the Fischer-Tropsch, process, titania-supported cobalt catalysts have received great interest from industrial and academic, institutions. Here, we report on three catalyst preparation procedures, incipient wetness impregnation

  16. Effect of Carbon Supported Pt Catalysts on Selective Hydrogenation of Cinnamaldehyde

    Directory of Open Access Journals (Sweden)

    Qing Han

    2016-01-01

    Full Text Available Selective hydrogenation of cinnamaldehyde (CAL to cinnamyl alcohol (COL is of both fundamental and industrial interest. It is of great significance to evaluate the possible differences between different supports arising from metal dispersion and electronic effects, in terms of activity and selectivity. Herein, Pt catalysts on different carbon supports including carbon nanotubes (CNTs and reduced graphene oxides (RGO were developed by a simple wet impregnation method. The resultant catalysts were well characterized by XRD, Raman, N2 physisorption, TEM, and XPS analysis. Applied in the hydrogenation of cinnamaldehyde, 3.5 wt% Pt/CNT shows much higher selectivity towards cinnamyl alcohol (62% than 3.5 wt% Pt/RGO@SiO2 (48%. The enhanced activity can be ascribed to the high graphitization degree of CNTs and high density of dispersed Pt electron cloud.

  17. Bimetallic Ag-Pt Sub-nanometer Supported Clusters as Highly Efficient and Robust Oxidation Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Negreiros, Fabio R. [CNR-ICCOM & IPCF, Consiglio Nazionale delle Ricerche, Pisa Italy; Halder, Avik [Materials Science Division, Argonne National Laboratory, Lemont IL USA; Yin, Chunrong [Materials Science Division, Argonne National Laboratory, Lemont IL USA; Singh, Akansha [Harish-Chandra Research Institute, HBNI, Chhatnag Road Jhunsi Allahabad 211019 India; Barcaro, Giovanni [CNR-ICCOM & IPCF, Consiglio Nazionale delle Ricerche, Pisa Italy; Sementa, Luca [CNR-ICCOM & IPCF, Consiglio Nazionale delle Ricerche, Pisa Italy; Tyo, Eric C. [Materials Science Division, Argonne National Laboratory, Lemont IL USA; Pellin, Michael J. [Materials Science Division, Argonne National Laboratory, Lemont IL USA; Bartling, Stephan [Institut für Physik, Universität Rostock, Rostock Germany; Meiwes-Broer, Karl-Heinz [Institut für Physik, Universität Rostock, Rostock Germany; Seifert, Sönke [X-ray Science Division, Argonne National Laboratory, Lemont IL USA; Sen, Prasenjit [Harish-Chandra Research Institute, HBNI, Chhatnag Road Jhunsi Allahabad 211019 India; Nigam, Sandeep [Chemistry Division, Bhabha Atomic Research Centre, Trombay Mumbai- 400 085 India; Majumder, Chiranjib [Chemistry Division, Bhabha Atomic Research Centre, Trombay Mumbai- 400 085 India; Fukui, Nobuyuki [East Tokyo Laboratory, Genesis Research Institute, Inc., Ichikawa Chiba 272-0001 Japan; Yasumatsu, Hisato [Cluster Research Laboratory, Toyota Technological Institute: in, East Tokyo Laboratory, Genesis Research Institute, Inc. Ichikawa, Chiba 272-0001 Japan; Vajda, Stefan [Materials Science Division, Argonne National Laboratory, Lemont IL USA; Nanoscience and Technology Division, Argonne National Laboratory, Lemont IL USA; Institute for Molecular Engineering, University of Chicago, Chicago IL USA; Fortunelli, Alessandro [CNR-ICCOM & IPCF, Consiglio Nazionale delle Ricerche, Pisa Italy; Materials and Process Simulation Center, California Institute of Technology, Pasadena CA USA

    2017-12-29

    A combined experimental and theoretical investigation of Ag-Pt sub-nanometer clusters as heterogeneous catalysts in the CO -> CO2 reaction (COox) is presented. Ag9Pt2 and Ag9Pt3 clusters are size-selected in the gas phase, deposited on an ultrathin amorphous alumina support, and tested as catalysts experimentally under realistic conditions and by first-principles simulations at realistic coverage. Insitu GISAXS/TPRx demonstrates that the clusters do not sinter or deactivate even after prolonged exposure to reactants at high temperature, and present comparable, extremely high COox catalytic efficiency. Such high activity and stability are ascribed to a synergic role of Ag and Pt in ultranano-aggregates, in which Pt anchors the clusters to the support and binds and activates two CO molecules, while Ag binds and activates O-2, and Ag/Pt surface proximity disfavors poisoning by CO or oxidized species.

  18. Networks of connected Pt nanoparticles supported on carbon nanotubes as superior catalysts for methanol electrooxidation

    Science.gov (United States)

    Huang, Meihua; Zhang, Jianshuo; Wu, Chuxin; Guan, Lunhui

    2017-02-01

    The high cost and short lifetime of the Pt-based anode catalyst for methanol oxidation reaction (MOR) hamper the widespread commercialization of direct methanol fuel cell (DMFC). Therefore, improving the activity of Pt-based catalysts is necessary for their practical application. For the first time, we prepared networks of connected Pt nanoparticles supported on multi-walled carbon nanotubes with loading ratio as high as 91 wt% (Pt/MWCNTs). Thanks for the unique connected structure, the Pt mass activity of Pt/MWCNTs for methanol oxidation reaction is 4.4 times as active as that of the commercial Pt/C (20 wt%). When carbon support is considered, the total mass activity of Pt/MWCNTs is 20 times as active as that of the commercial Pt/C. The durability and anti-poisoning ability are also improved greatly.

  19. Final Report - Advanced Cathode Catalysts and Supports for PEM Fuel Cells

    Energy Technology Data Exchange (ETDEWEB)

    Debe, Mark

    2012-09-28

    The principal objectives of the program were development of a durable, low cost, high performance cathode electrode (catalyst and support), that is fully integrated into a fuel cell membrane electrode assembly with gas diffusion media, fabricated by high volume capable processes, and is able to meet or exceed the 2015 DOE targets. Work completed in this contract was an extension of the developments under three preceding cooperative agreements/grants Nos. DE-FC-02-97EE50473, DE-FC-99EE50582 and DE-FC36- 02AL67621 which investigated catalyzed membrane electrode assemblies for PEM fuel cells based on a fundamentally new, nanostructured thin film catalyst and support system, and demonstrated the feasibility for high volume manufacturability.

  20. Spectroscopic evidence for origins of size and support effects on selectivity of Cu nanoparticle dehydrogenation catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Witzke, M. E.; Dietrich, P. J.; Ibrahim, M. Y. S.; Al-Bardan, K.; Triezenberg, M. D.; Flaherty, D. W.

    2016-12-12

    Selective dehydrogenation catalysts that produce acetaldehyde from bio-derived ethanol can increase the efficiency of subsequent processes such as C–C coupling over metal oxides to produce 1-butanol or 1,3-butadiene or oxidation to acetic acid. Here, we use in situ X-ray absorption spectroscopy and steady state kinetics experiments to identify Cuδ+ at the perimeter of supported Cu clusters as the active site for esterification and Cu0 surface sites as sites for dehydrogenation. Correlation of dehydrogenation and esterification selectivities to in situ measures of Cu oxidation states show that this relationship holds for Cu clusters over a wide-range of diameters (2–35 nm) and catalyst supports and reveals that dehydrogenation selectivities may be controlled by manipulating either.

  1. Gold Supported on Graphene Oxide: An Active and Selective Catalyst for Phenylacetylene Hydrogenations at Low Temperatures

    DEFF Research Database (Denmark)

    Shao, Lidong; Huang, Xing; Teschner, Detre

    2014-01-01

    A constraint to industrial implementation of gold-catalyzed alkyne hydrogenation is that the catalytic activity was always inferior to those of other noble metals. In this work, gold was supported on graphene oxide (Au/GO) and used in a hydrogenation application. A 99% selectivity toward styrene...... with a 99% conversion in the hydrogenation of phenylacetylene was obtained at 60 °C, which is 100 to 200 °C lower than optimal temperatures in most previous reports on Au catalysts. A series of gold- and palladium-based reference catalysts were tested under the same conditions for phenylacetylene...... hydrogenation, and the performance of Au/GO was substantiated by studying the role of functionalized GO in governing the geometrical structure and thermal stability of supported Au nanoparticles under reaction conditions....

  2. Catalytic oxidation of pulping effluent by activated carbon-supported heterogeneous catalysts.

    Science.gov (United States)

    Yadav, Bholu Ram; Garg, Anurag

    2016-01-01

    The present study deals with the non-catalytic and catalytic wet oxidation (CWO) for the removal of persistent organic compounds from the pulping effluent. Two activated carbon-supported heterogeneous catalysts (Cu/Ce/AC and Cu/Mn/AC) were used for CWO after characterization by the following techniques: temperature-programmed reduction, Fourier transform infrared spectroscopy and thermo-gravimetric analysis. The oxidation reaction was performed in a batch high-pressure reactor (capacity = 0.7  L) at moderate oxidation conditions (temperature = 190°C and oxygen pressure = 0.9 MPa). With Cu/Ce/AC catalyst, the maximum chemical oxygen demand (COD), total organic carbon (TOC) and lignin removals of 79%, 77% and 88% were achieved compared to only 50% removal during the non-catalytic process. The 5-day biochemical oxygen demand (BOD5) to COD ratio (a measure for biodegradability) of the pulping effluent was improved to 0.52 from an initial value of 0.16. The mass balance calculations for solid recovered after CWO reaction showed 8% and 10% deduction in catalyst mass primarily attributed to the loss of carbon and metal leaching. After the CWO process, carbon deposition was also observed on the recovered catalyst which was responsible for around 3-4% TOC reduction.

  3. Self-Supporting Metal-Organic Layers as Single-Site Solid Catalysts.

    Science.gov (United States)

    Cao, Lingyun; Lin, Zekai; Peng, Fei; Wang, Weiwei; Huang, Ruiyun; Wang, Cheng; Yan, Jiawei; Liang, Jie; Zhang, Zhiming; Zhang, Teng; Long, Lasheng; Sun, Junliang; Lin, Wenbin

    2016-04-11

    Metal-organic layers (MOLs) represent an emerging class of tunable and functionalizable two-dimensional materials. In this work, the scalable solvothermal synthesis of self-supporting MOLs composed of [Hf6O4(OH)4(HCO2)6] secondary building units (SBUs) and benzene-1,3,5-tribenzoate (BTB) bridging ligands is reported. The MOL structures were directly imaged by TEM and AFM, and doped with 4'-(4-benzoate)-(2,2',2''-terpyridine)-5,5''-dicarboxylate (TPY) before being coordinated with iron centers to afford highly active and reusable single-site solid catalysts for the hydrosilylation of terminal olefins. MOL-based heterogeneous catalysts are free from the diffusional constraints placed on all known porous solid catalysts, including metal-organic frameworks. This work uncovers an entirely new strategy for designing single-site solid catalysts and opens the door to a new class of two-dimensional coordination materials with molecular functionalities. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Self-Supporting Metal-Organic Layers as Single-Site Solid Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Lingyun; Lin, Zekai; Peng, Fei; Wang, Weiwei; Huang, Ruiyun; Wang, Cheng; Yan, Jiawei; Liang, Jie; Zhang, Zhiming; Zhang, Teng; Long, Lasheng; Sun, Junliang; Lin, Wenbin (StockholmU); (UC); (Xiamen)

    2016-03-08

    Metal–organic layers (MOLs) represent an emerging class of tunable and functionalizable two-dimensional materials. In this work, the scalable solvothermal synthesis of self-supporting MOLs composed of [Hf6O4(OH)4(HCO2)6] secondary building units (SBUs) and benzene-1,3,5-tribenzoate (BTB) bridging ligands is reported. The MOL structures were directly imaged by TEM and AFM, and doped with 4'-(4-benzoate)-(2,2',2''-terpyridine)-5,5''-dicarboxylate (TPY) before being coordinated with iron centers to afford highly active and reusable single-site solid catalysts for the hydrosilylation of terminal olefins. MOL-based heterogeneous catalysts are free from the diffusional constraints placed on all known porous solid catalysts, including metal–organic frameworks. This work uncovers an entirely new strategy for designing single-site solid catalysts and opens the door to a new class of two-dimensional coordination materials with molecular functionalities.

  5. Using supported Au nanoparticles as starting material for preparing uniform Au/Pd bimetallic catalysts

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-01-01

    One of the best methods for producing bulk homogeneous (composition) supported bimetallic AuPd clusters involves the immobilization of a protected Au seed followed by the addition of Pd. This paper investigates the importance of this gold seed in controlling the resulting bimetallic AuPd clusters structures, sizes and catalytic activities by investigating three different gold seeds. Uniform Au-Pd alloy were obtained when a steric/electrostatic protecting group, poly(vinyl alcohol) (PVA), was used to form the gold clusters on activated carbon (AC). In contrast Au/AC precursors prepared using Au nanoparticles with only electrostatic stabilization (tetrakis(hydroxypropyl)phosphonium chloride (THPC)), or no stabilization (magnetron sputtering) produced inhomogeneous alloys and segregation of the gold and palladium. The uniform alloyed catalyst (Pd{at}Au{sub PVA}/AC) is the most active and selective catalyst, while the inhomogenous catalysts are less active and selective. Further study of the PVA protected Au clusters revealed that the amount of PVA used is also critical for the preparation of uniform alloyed catalyst, their stability, and their catalytic activity.

  6. How nitric oxide affects the decomposition of supported nickel nitrate to arrive at highly dispersed catalysts

    NARCIS (Netherlands)

    Sietsma, J.R.A.; Friedrich, H.|info:eu-repo/dai/nl/304837350; Broersma, A.|info:eu-repo/dai/nl/311437532; Versluijs-Helder, M.|info:eu-repo/dai/nl/311472699; van Dillen, A.J.|info:eu-repo/dai/nl/111157625; de Jongh, P.E.|info:eu-repo/dai/nl/186125372; de Jong, K.P.|info:eu-repo/dai/nl/06885580X

    2008-01-01

    An explanation is put forward for the beneficial effect of thermal decomposition of supported Ni3(NO3)2(OH)4 in NO/He flow (0.1–1 vol%) that enables preparation of well-dispersed (3–5 nm particles) 24 wt% Ni-catalysts via impregnation and drying using aqueous [Ni(OH2)6](NO3)2 precursor solution.

  7. Effect of water vapour on the molecular structures of supported vanadium oxide catalysts at elevated temperatures

    NARCIS (Netherlands)

    Jehng, Jih-Mirn; Deo, G.; Weckhuysen, B.M.; Wachs, I.E.

    1996-01-01

    The effect of water vapor on the molecular structures of V2O3-supported catalysts (SiO2, Al2o3, TiO2, and CeO2) was investigated by in situ Raman spectroscopy as a function of temperature (from 500°C to 120°C). Under dry conditions only isolated surface VO4 species are present on the dehydrated SiO2

  8. Highly selective and active niobia-supported cobalt catalysts for fischer-tropsch synthesis

    NARCIS (Netherlands)

    Den Otter, Jan H.|info:eu-repo/dai/nl/337238774; De Jong, Krijn P.|info:eu-repo/dai/nl/06885580X

    The performance of Co/Nb2O5 was compared to that of Co/γ-Al2O3 for the Fischer-Tropsch synthesis at 20 bar and over the temperature range of 220-260°C. The C5+ selectivity of Nb2O5-supported cobalt catalysts was found to be very high, i.e. up to 90 wt% C5+ at 220°C. The activity per unit weight

  9. Wet Oxidation of Maleic Acid by a Pumice Supported Copper (II ...

    African Journals Online (AJOL)

    Pumice supported Cu (II) Schiff base catalysts were prepared by surface chemical modification followed by complexation with Cu (II) acetate. The resulting materials were characterised by Diffuse Reflectance Fourier Transform Spectroscopy (DRIFTS) to confirm the modification. The materials were tested in a wet oxidation ...

  10. Catalytic partial oxidation of methane over porous silica supported VO{sub x} catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Pirovano, C.; Schoenborn, E.; Kalevaru, V.N.; Wohlrab, S.; Luecke, B.; Martin, A. [University Rostock e.V., Rostock (Germany). Leibniz Inst. for Catalysis

    2011-07-01

    High surface area mesoporous siliceous MCM-41 and SBA-15 materials have been used as supports to disperse vanadium oxide species using wet impregnation and incipient wetness impregnation methods. These materials were used as catalysts for the partial oxidation of methane (POM) to formaldehyde. The physico-chemical properties of the solids were studied by means of BET, DR-UV/Vis spectroscopy, Py-FTIR and TEM. The influence of support and the preparation method on the dispersion of VOx is also investigated. The catalytic properties of the catalysts were examined in a fixed bed stainless steel reactor at 923 K. So far a maximum production of formaldehyde can be detected on SBA-15 supported VOx-catalysts prepared by incipient wetness impregnation. On this V/SBA-15 material a covalent attachment of catalytic active molecular vanadium species dominates, which in turn leads to a lower activation temperature and thereby reduced over-oxidation. From the best case, the space time yield of HCHO could be reached close to 775 g{sub HCHO} Kg{sub cat}{sup -1} h{sup -1}. (orig.)

  11. Dimethyl carbonate synthesis via transesterification of propylene carbonate with methanol by ceria-zinc catalysts: Role of catalyst support and reaction parameters

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Praveen; Srivastava, Vimal Chandra; Mishra, Indra Mani [Indian Institute of Technology Roorkee, Roorkee 247667, Uttarakhand (India)

    2015-09-15

    Ceria and zinc oxide catalyst were impregnated onto various oxide supports, namely Al{sub 2}O{sub 3}, TiO{sub 2} and SiO{sub 2}, individually by deposition-coprecipitation method. The synthesized catalysts (CZA, CZS and CZT having supports Al{sub 2}O{sub 3}, TiO{sub 2} and SiO{sub 2}, respectively) were characterized by X-ray diffraction (XRD), NH{sub 3}- and CO{sub 2}-temperature programmed desorption (TPD) and N2 adsorption. These catalysts were used for synthesis of dimethyl carbonate (DMC) from methanol and propylene carbonate in a batch reactor. CZS was found to have larger average grain size as compared to CZA and CZT. Composite oxides (catalysts) were found to contain individual phases of ZnO, CeO{sub 2} and some spinel forms of Zn, Ce along with their supports. CZS having highest basicity and surface area showed better catalytic activity as compared to CZA and CZT. Effect of reaction temperature and methanol/PC molar ratio on DMC yield was studied and a reaction mechanism has been discussed. Maximum DMC yield of 77% was observed with CZS catalyst at 170 .deg. C with methanol/PC molar ratio of 10.

  12. Polyol Synthesis of Cobalt–Copper Alloy Catalysts for Higher Alcohol Synthesis from Syngas

    DEFF Research Database (Denmark)

    Mendes, Laiza V.P.; Snider, Jonathan L.; Fleischman, Samuel D.

    2017-01-01

    and after catalytic testing in a flow reactor at 250 °C and 40 bar. The results show alloyed phases were obtained using the polyol method, resulting in selectivity towards higher alcohols, as high as 11.3% when supported on alumina. Segregation of cobalt and the formation of cobalt carbide were observed...

  13. Hydrogen production by auto-thermal reforming of ethanol over nickel catalyst supported on metal oxide-stabilized zirconia

    Energy Technology Data Exchange (ETDEWEB)

    Youn, Min Hye; Seo, Jeong Gil; Song, In Kyu [School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, Shinlim-dong, Kwanak-ku, Seoul 151-744 (Korea)

    2010-04-15

    Metal oxide-stabilized mesoporous zirconia supports (M-ZrO{sub 2}) with different metal oxide stabilizer (M = Zr, Y, La, Ca, and Mg) were prepared by a templating sol-gel method. 20 wt% Ni catalysts supported on M-ZrO{sub 2} (M = Zr, Y, La, Ca, and Mg) were then prepared by an incipient wetness impregnation method for use in hydrogen production by auto-thermal reforming of ethanol. The effect of metal oxide stabilizer (M = Zr, Y, La, Ca, and Mg) on the catalytic performance of supported nickel catalysts was investigated. Ni/M-ZrO{sub 2} (M = Y, La, Ca, and Mg) catalysts exhibited a higher catalytic performance than Ni/Zr-ZrO{sub 2}, because surface oxygen vacancy of M-ZrO{sub 2} (M = Y, La, Ca, and Mg) and reducibility of Ni/M-ZrO{sub 2} (M = Y, La, Ca, and Mg) were enhanced by the addition of lower valent metal cation. Hydrogen yield over Ni/M-ZrO{sub 2} (M = Zr, Y, La, Ca, and Mg) catalyst was monotonically increased with increasing both surface oxygen vacancy of M-ZrO{sub 2} support and reducibility of Ni/M-ZrO{sub 2} catalyst. Among the catalysts tested, Ni catalyst supported on yttria-stabilized mesoporous zirconia (Ni/Y-ZrO{sub 2}) showed the best catalytic performance. (author)

  14. Kinetics of p-nitrophenol reduction by copper - porous silicon catalyst in the presence of KBH4

    Science.gov (United States)

    Bakar, N. H. H. Abu; Ridzwan, A.; Tan, W. L.; Bakar, M. Abu; Sabri, N. A.

    2017-04-01

    Copper supported on porous silicon (Cu-PS) was prepared via deposition of Cu° on the surface of chemically etched PS powder. The particle size of Cu° varied with the Cu content in Cu-PS. The distribution of Cu° in or around the pores of PS resulted in a lower BET surface area and pore size of the Cu-PS as compared to pristine PS. Catalytic efficiency of Cu-PS was evaluated for the reduction of p-nitrophenol (p-NP). Optimum conditions were achieved when 0.77 wt% Cu-PS and 25.00 mg KBH4 was used. Cu-PS also exhibit sustainable catalytic activity.

  15. Hydrogen purification for fuel cell by copper promoted gold catalysts; Purificacao de hidrogenio para pilha a combustivel utilizando catalisadores de ouro promovidos com cobre

    Energy Technology Data Exchange (ETDEWEB)

    Mozer, Thiago S.; Vieira, Carlos T.P.; Passos, Fabio B. [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil); Dziuba, Dominika A. [Hochschule Mannheim (Germany)

    2008-07-01

    Copper promoted gold catalysts were studied for hydrogen purification through selective CO oxidation. The Cu acted as a selectivity promoter favoring the CO conversion and decreasing the H{sub 2} consumption. The deposition-precipitation method, used to prepare the samples generated small and well dispersed gold particles, as the UV-vis DRS spectra did not show the 'plasmon' band, which indicates that the samples are active for SELOX. The activity tests showed high CO conversion, the bimetallic 2,5%Au-0,5%Cu/Al{sub 2}O{sub 3} catalyst showed the best behavior in the tested condition, 95% of CO conversion and 75% of selectivity at 50 deg C. Increasing the O{sub 2} content in the feedstream the CO conversion also increased, although the selectivity decreased. (author)

  16. Carbon-Supported Pd and PdFe Alloy Catalysts for Direct Methanol Fuel Cell Cathodes

    Directory of Open Access Journals (Sweden)

    Luis M. Rivera Gavidia

    2017-05-01

    Full Text Available Direct methanol fuel cells (DMFCs are electrochemical devices that efficiently produce electricity and are characterized by a large flexibility for portable applications and high energy density. Methanol crossover is one of the main obstacles for DMFC commercialization, forcing the search for highly electro-active and methanol tolerant cathodes. In the present work, carbon-supported Pd and PdFe catalysts were synthesized using a sodium borohydride reduction method and physico-chemically characterized using transmission electron microscopy (TEM and X-ray techniques such as photoelectron spectroscopy (XPS, diffraction (XRD and energy dispersive spectroscopy (EDX. The catalysts were investigated as DMFC cathodes operating at different methanol concentrations (up to 10 M and temperatures (60 °C and 90 °C. The cell based on PdFe/C cathode presented the best performance, achieving a maximum power density of 37.5 mW·cm−2 at 90 °C with 10 M methanol, higher than supported Pd and Pt commercial catalysts, demonstrating that Fe addition yields structural changes to Pd crystal lattice that reduce the crossover effects in DMFC operation.

  17. Carbon-Supported Pd and PdFe Alloy Catalysts for Direct Methanol Fuel Cell Cathodes.

    Science.gov (United States)

    Rivera Gavidia, Luis M; Sebastián, David; Pastor, Elena; Aricò, Antonino S; Baglio, Vincenzo

    2017-05-25

    Direct methanol fuel cells (DMFCs) are electrochemical devices that efficiently produce electricity and are characterized by a large flexibility for portable applications and high energy density. Methanol crossover is one of the main obstacles for DMFC commercialization, forcing the search for highly electro-active and methanol tolerant cathodes. In the present work, carbon-supported Pd and PdFe catalysts were synthesized using a sodium borohydride reduction method and physico-chemically characterized using transmission electron microscopy (TEM) and X-ray techniques such as photoelectron spectroscopy (XPS), diffraction (XRD) and energy dispersive spectroscopy (EDX). The catalysts were investigated as DMFC cathodes operating at different methanol concentrations (up to 10 M) and temperatures (60 °C and 90 °C). The cell based on PdFe/C cathode presented the best performance, achieving a maximum power density of 37.5 mW·cm-2 at 90 °C with 10 M methanol, higher than supported Pd and Pt commercial catalysts, demonstrating that Fe addition yields structural changes to Pd crystal lattice that reduce the crossover effects in DMFC operation.

  18. An investigation into the effects of different existing states of aluminum isopropoxide on copper-based catalysts for direct synthesis of dimethyl ether from syngas

    Science.gov (United States)

    Sun, Kai; Wang, Peng; Bian, Zhongkai; Huang, Wei

    2018-01-01

    Aluminum isopropoxide (AIP) is a vital raw material to produce high surface area alumina catalyst, which is used for catalytic applications, such as hydrocracking, Fischer-Tropsch and STD (syngas to dimethyl ether) reactions. However, the different existing states have an effect on hydrolysis and condensation in the process of precursor preparation. The Cu/Zn/Al slurry catalysts were prepared by aluminum isopropoxide, which were liquid state, crystalline state and solid state, utilizing a complete liquid phase preparation technology. In the dimethyl ether (DME) synthesis reaction, the aluminum resource of crystalline state was prepared for slurry catalyst, which presented high CO conversion and DME selectivity of 54.32% and 69.74%, respectively. Characterization results indicated that different forms of AIP have the variant coordination numbers of Al-O and polymerization degrees, and the catalyst prepared by crystalline state consists amount of tetra-coordinated Al and few hexa-coordinated Al, which can exert different hydrolysis and condensation process compared with other aluminum sources, and finally it contributes to the strong interaction between active site copper species and Zn/Al species, confirming more Cu+ is responsible for the synthesis of DME in the slurry reactor.

  19. Nitrogen-Doped Carbon Nanotube-Supported Pd Catalyst for Improved Electrocatalytic Performance toward Ethanol Electrooxidation

    Science.gov (United States)

    Wei, Ying; Zhang, Xinyuan; Luo, Zhiyong; Tang, Dian; Chen, Changxin; Zhang, Teng; Xie, Zailai

    2017-07-01

    In this study, hydrothermal carbonization (HTC) was applied for surface functionalization of carbon nanotubes (CNTs) in the presence of glucose and urea. The HTC process allowed the deposition of thin nitrogen-doped carbon layers on the surface of the CNTs. By controlling the ratio of glucose to urea, nitrogen contents of up to 1.7 wt% were achieved. The nitrogen-doped carbon nanotube-supported Pd catalysts exhibited superior electrochemical activity for ethanol oxidation relative to the pristine CNTs. Importantly, a 1.5-fold increase in the specific activity was observed for the Pd/HTC-N1.67%CNTs relative to the catalyst without nitrogen doping (Pd/HTC-CNTs). Further experiments indicated that the introduction of nitrogen species on the surface of the CNTs improved the Pd(0) loading and increased the binding energy.

  20. Aluminum Oxide Formation On Fecral Catalyst Support By Electro-Chemical Coating

    Directory of Open Access Journals (Sweden)

    Yang H.S.

    2015-06-01

    Full Text Available FeCrAl is comprised essentially of Fe, Cr, Al and generally considered as metallic substrates for catalyst support because of its advantage in the high-temperature corrosion resistance, high mechanical strength, and ductility. Oxidation film and its adhesion on FeCrAl surface with aluminum are important for catalyst life. Therefore various appropriate surface treatments such as thermal oxidation, Sol, PVD, CVD has studied. In this research, PEO (plasma electrolytic oxidation process was applied to form the aluminum oxide on FeCrAl surface, and the formed oxide particle according to process conditions such as electric energy and oxidation time were investigated. Microstructure and aluminum oxide particle on FeCrAl surface after PEO process was observed by FE-SEM and EDS with element mapping analysis. The study presents possibility of aluminum oxide formation by electro-chemical coating process without any pretreatment of FeCrAl.

  1. A Copper-Based Metal-Organic Framework as an Efficient and Reusable Heterogeneous Catalyst for Ullmann and Goldberg Type C–N Coupling Reactions

    Directory of Open Access Journals (Sweden)

    Wei Long

    2015-11-01

    Full Text Available A highly porous metal-organic framework (Cu-TDPAT, constructed from a paddle-wheel type dinuclear copper cluster and 2,4,6-tris(3,5-dicarboxylphenylamino-1,3,5-triazine (H6TDPAT, has been tested in Ullmann and Goldberg type C–N coupling reactions of a wide range of primary and secondary amines with halobenzenes, affording the corresponding N-arylation compounds in moderate to excellent yields. The Cu-TDPAT catalyst could be easily separated from the reaction mixtures by simple filtration, and could be reused at least five times without any significant degradation in catalytic activity.

  2. In Situ Diffuse Reflectance Spectroscopy of Supported Chromium Oxide Catalysts: Kinetics of the Reduction Process with Carbon Monoxide

    NARCIS (Netherlands)

    Bensalem, A.; Weckhuysen, B.M.; Schoonheydt, R.A.

    1996-01-01

    In situ diffuse reflectance spectra of supported chromium oxide catalysts are investigated for the first time at elevated temperatures under controlled reaction conditions using a specially designed diffuse reflection attachment. The obtained results are compared and discussed with those obtained

  3. Role of the support in the formation of the active phase of catalysts for the hydrogenation of carbon monoxide

    Energy Technology Data Exchange (ETDEWEB)

    Kamalov, G.K.; Povolotskii, E.Yu.; Silant`eva, O.A. [A.V. Bogatskii Institute of Physical Chemistry, Odessa (Ukraine)] [and others

    1992-03-01

    A series of supports, i.e., substitutional solid solutions of metal oxides in an Al{sub 2}O{sub 3} matrix, which can be used to prepare Co and Ni-containing catalysts for the hydrogenation of carbon monoxide, has been obtained. It has been shown that the activity of the catalysts correlates closely with the donor-acceptor properties of the supports and that the character of the laws discovered in largely determined by the extent of reduction of the active phase of the catalysts. 20 refs., 7 figs., 1 tab.

  4. Novel carbon nanostructures as catalyst support for polymer electrolyte membrane fuel cells

    Science.gov (United States)

    Natarajan, Sadesh Kumar

    Polymer electrolyte membrane fuel cell (PEMFC) technology has advanced rapidly in recent years, with one of active area focused on improving the long-term performance of carbon supported catalysts, which has been recognized as one of the most important issues to be addressed for the commercialization of PEMFCs. The central part of a PEMFC is the membrane electrode assembly (MEA) which consists of two electrodes (anode and cathode) and a cation exchange membrane. These electrodes are commonly made of carbon black (most often, Vulcan XC-72) supported on carbon paper or carbon cloth backings. It is the primary objective of this thesis to prepare and investigate carbon nanostructures (CNS, licensed to Hydrogen Research Institute -- IRH, Quebec, Canada), the carbon material with more graphite component like carbon nanotubes (CNTs) for use as catalyst support in PEMFCs. High energy ball-milling of activated carbon along with transition metal catalysts under hydrogen atmosphere, followed by heat-treatment leads to nanocrystalline structures of carbon called CNS. However, CNS formed in the quartz tube after heat-treatment is inevitably accompanied by many impurities such as metal particles, amorphous carbon and other carbon nanoparticules. Such impurities are a serious impediment to detailed characterization of the properties of nanostructures. In addition, since the surface of CNS is itself rather inert, it is difficult to control the homogeneity and size distribution of Pt nanoparticules. In this thesis work, we demonstrated a novel mean to purify and functionalize CNS via acid-oxidation under reflux conditions. To investigate and quantify these nanostructures X-ray diffraction, electrical conductivity measurements, specific surface area measurements, thermogravimetric analysis, X-ray photoelectron spectroscopy and transmission electron microscopy studies were used. Cyclic voltammetry studies were performed on different samples to derive estimates for the relationship

  5. Pelletization of catalysts supported on activated carbon. A Case Study : clean synthesis of dimethyl carbonate from methanol and CO2

    OpenAIRE

    Orrego Romero, Andrés Felipe; Arbeláez Pérez, Oscar Felipe; Bustamante Londoño, Felipe; Villa Holguín, Aída Luz

    2016-01-01

    The synthesis of Cu-Ni bimetallic catalyst supported on pellets of activated carbon using carboxymethylcellulose (CMC) as a binder is reported. The effect of preparation conditions, such as binder concentration, AC/binder ratio, temperature, and pyrolysis heating rate on the surface area of the pellets, was evaluated. Cu and Ni metals were incorporated on the pellets by conventional incipient wetness impregnation. The support and the synthesized catalysts were characterized using N2 adsorptio...

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

    Energy Technology Data Exchange (ETDEWEB)

    T. Brent Gunnoe

    2011-02-17

    , which has provided a comprehensive understanding of the impact of steric and electronic parameters of 'L' on the catalytic hydroarylation of olefins. (3) We have completed and published a detailed mechanistic study of stoichiometric aromatic C-H activation by TpRu(L)(NCMe)Ph (L = CO or PMe{sub 3}). These efforts have probed the impact of functionality para to the site of C-H activation for benzene substrates and have allowed us to develop a detailed model of the transition state for the C-H activation process. These results have led us to conclude that the C-H bond cleavage occurs by a {sigma}-bond metathesis process in which the C-H transfer is best viewed as an intramolecular proton transfer. (4) We have completed studies of Ru complexes possessing the N-heterocyclic carbene IMes (IMes = 1,3-bis-(2,4,6-trimethylphenyl)imidazol-2-ylidene). One of these systems is a unique four-coordinate Ru(II) complex that catalyzes the oxidative hydrophenylation of ethylene (in low yields) to produce styrene and ethane (utilizing ethylene as the hydrogen acceptor) as well as the hydrogenation of olefins, aldehydes and ketones. These results provide a map for the preparation of catalysts that are selective for oxidative olefin hydroarylation. (5) The ability of TpRu(PMe{sub 3})(NCMe)R systems to activate sp{sup 3} C-H bonds has been demonstrated including extension to subsequent C-C bond forming steps. These results open the door to the development of catalysts for the functionalization of more inert C-H bonds. (6) We have discovered that Pt(II) complexes supported by simple nitrogen-based ligands serve as catalysts for the hydroarylation of olefins. Given the extensive studies of Pt-based catalytic C-H activation, we believe these results will provide an entry point into an array of possible catalysts for hydrocarbon functionalization.

  7. Partial Oxidation of Hydrocarbons in a Segmented Bed Using Oxide-based Catalysts and Oxygen-conducting Supports

    Science.gov (United States)

    Smith, Mark W.

    Two objectives for the catalytic reforming of hydrocarbons to produce synthesis gas are investigated herein: (1) the effect of oxygen-conducting supports with partially substituted mixed-metal oxide catalysts, and (2) a segmented bed approach using different catalyst configurations. Excess carbon deposition was the primary cause of catalyst deactivation, and was the focus of the experiments for both objectives. The formation and characterization of deposited carbon was examined after reaction for one of the selected catalysts to determine the quantity and location of the carbon on the catalyst surface leading to deactivation. A nickel-substituted barium hexaaluminate (BNHA), with the formula BaAl 11.6Ni0.4O18.8, and a Rh-substituted lanthanum zirconate pyrochlore (LCZR) with the formula La1.89Ca0.11 Zr1.89Rh0.11, were combined with two different doped ceria supports. These supports were gadolinium-doped ceria (GDC) and zirconium-doped ceria (ZDC). The active catalyst phases were combined with the supports in different ratios using different synthesis techniques. The catalysts were characterized using several different techniques and were tested under partial oxidation (POX) of n-tetradecane (TD), a diesel fuel surrogate. It was found that the presence of GDC and ZDC reduced the formation of carbon for both catalysts; the optimal ratio of catalyst to support was different for the hexaaluminate and the pyrochlore; a loading of 20 wt% of the pyrochlore with ZDC produced the most stable performance in the presence of common fuel contaminants (>50 h); and, the incipient wetness impregnation synthesis method of applying the active catalyst to the support produced more stable product yields than the catalyst prepared by a solid-state mixing technique. Different hexaaluminate and pyrochlore catalysts were used in different configurations in a segmented bed approach. The first strategy was to promote the indirect reforming mechanism by placing a combustion catalyst in the

  8. Evaluation of CO oxidation over Co3O4-supported NiO catalysts

    Science.gov (United States)

    Sie, Min-Chun; Jeng, Pei-Di; Chen, Pin-Hsuan; Wu, Ruei-Ci; Wang, Chen-Bin

    2017-09-01

    The process of doping NiO onto Co3O4 for achieving resistance to sintering and obtaining long-term stability of catalytic activity was examined herein. A sample of cobalt oxide (Co3O4) was prepared from Co(NO3)2.6H2O via precipitation by NaOH, and then calcined at 300 and 500 °C. The Co3O4-supported NiO catalysts were prepared by deposited precipitation of Ni(NO3)2.6H2O with NaOH added in a dropwise manner into the suspended Co3O4 solution with various loading of nickel. Then, oxidation with NaOCl was employed to obtain NiO/Co3O4 catalysts (weight loading of Ni: 0.1 ˜ 5 wt%). All of the samples were characterized by using XRD, SEM/TEM, BET, TPR and TGA techniques. Catalytic activities related to CO oxidation were tested from 0 to 200 °C in a self-designed fluidized micro-reactor. The results showed that the calcination temperature and loading of nickel were important parameters in the preparation process. With the lower calcined temperature and loading of nickel below 1 wt%, all the samples showed high initial catalytic activity for CO oxidation near room temperature. The synergistic effect can induce CO oxidation between NiO and Co3O4, and probably constitute a more suitable redox property for the 0.2%Ni/Co3O4 (C3) catalyst. Furthermore, only a slight decrease of CO conversion (less than 5%) was observed after 50 h of continuous reaction under 125 °C on this catalyst. The CO conversion could still remain above 75% after 50 h, which demonstrates that the 0.2%Ni/Co3O4 (C3) sample can function as a durable CO oxidation catalyst. We confirmed that our designed catalysts, based on tiny NiO nanoparticles, can be used as a component of a toxic gas abatement system.

  9. Selective liquid phase oxidation of benzyl alcohol to benzaldehyde by tert-butyl hydroperoxide over γ-Al{sub 2}O{sub 3} supported copper and gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Ndolomingo, Matumuene Joe; Meijboom, Reinout, E-mail: rmeijboom@uj.ac.za

    2017-03-15

    Highlights: • Cu and Au on γ-Al{sub 2}O{sub 3} catalysts were prepared and characterized. • Benzyl alcohol oxidation to benzaldehyde was performed by tert-butyl hydroperoxide in the absence of any solvent using the prepared catalysts. • The as prepared catalysts exhibited good performance in terms of conversion and selectivity towards benzaldehyde. • The kinetics of the reaction was investigated; k{sub app} was proportional to the amount of nano catalyst and oxidant present in the system. • The catalysts was recycled and reused with neither significant loss of activity nor selectivity. - Abstract: Benzyl alcohol oxidation to benzaldehyde was performed by tert-butyl hydroperoxide (TBHP) in the absence of any solvent using γ-Al{sub 2}O{sub 3} supported copper and gold nanoparticles. Li{sub 2}O and ionic liquids were used as additive and stabilizers for the synthesis of the catalysts. The physico-chemical properties of the catalysts were characterized by atomic absorption spectroscopy (AAS), X-ray diffraction spectroscopy (XRD), N{sub 2} absorption/desorption (BET), transmission electron microscopy (TEM), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and temperature programmed reduction (TPR), whereas, the oxidation reaction was followed by gas chromatography with a flame ionization detector (GC-FID). The as prepared catalysts exhibited good catalytic performance in terms of conversion and selectivity towards benzaldehyde. The performance of the Au-based catalysts is significantly higher than that of the Cu-based catalysts. For both Cu and Au catalysts, the conversion of benzyl alcohol increased as the reaction proceeds, while the selectivity for benzaldehyde decreased. Moreover, the catalysts can be easily recycled and reused with neither significant loss of activity nor selectivity. A kinetic study for the Cu and Au-catalyzed oxidation of benzyl alcohol to benzyldehyde is reported. The rate at which the oxidation of benzyl alcohol

  10. PREPARATION OF SPENT BLEACHING EARTH-SUPPORTED CALCIUM FROM LIMESTONE AS CATALYST IN TRANSESTERIFICATION OF WASTE FRYING OIL

    Directory of Open Access Journals (Sweden)

    Noor Hindryawati

    2017-06-01

    Full Text Available An investigation was conducted on palm oil refinery waste-spent bleaching earth (POR-SBE, POR-SBE supported by calcium as catalysts for methyl esters production through transesterification process using waste frying oil. The catalysts showed longer lasting activity than the traditional alkali catalysts. The optimum conditions for the process were: Ca-POR-SBE catalyst amount 7 %; methanol to oil molar ratio 12:1; and a reaction duration is 4 h. The process was able to transesterify oil to methyl esters at 96.8 % conversion at 65 °C. The catalysts were easily separated from the reaction mixture and the final product met selected biodiesel fuel properties in accordance with European Standard EN 14214.

  11. A packed bed membrane reactor for production of biodiesel using activated carbon supported catalyst.

    Science.gov (United States)

    Baroutian, Saeid; Aroua, Mohamed K; Raman, Abdul Aziz A; Sulaiman, Nik M N

    2011-01-01

    In this study, a novel continuous reactor has been developed to produce high quality methyl esters (biodiesel) from palm oil. A microporous TiO2/Al2O3 membrane was packed with potassium hydroxide catalyst supported on palm shell activated carbon. The central composite design (CCD) of response surface methodology (RSM) was employed to investigate the effects of reaction temperature, catalyst amount and cross flow circulation velocity on the production of biodiesel in the packed bed membrane reactor. The highest conversion of palm oil to biodiesel in the reactor was obtained at 70 °C employing 157.04 g catalyst per unit volume of the reactor and 0.21 cm/s cross flow circulation velocity. The physical and chemical properties of the produced biodiesel were determined and compared with the standard specifications. High quality palm oil biodiesel was produced by combination of heterogeneous alkali transesterification and separation processes in the packed bed membrane reactor. Copyright © 2010 Elsevier Ltd. All rights reserved.

  12. Activated Carbon Supported Mo-Ti-N Binary Transition Metal Nitride as Catalyst for Acetylene Hydrochlorination

    Directory of Open Access Journals (Sweden)

    Hui Dai

    2017-06-01

    Full Text Available Recently, many scientists have focused on the development of green industrial technology. However, the process of synthesizing vinyl chloride faces the problem of Hg pollution. Via a novel approach, we used two elements Mo and Ti to prepare an inexpensive and green binary transition metal nitride (BTMN as the active ingredient in a catalyst with nano-sized particles and an excellent degree of activation, which was supported on activated carbon. When the Mo/Ti mole ratio was 3:1, the conversion of acetylene reached 89% and the selectivity exceeded 98.5%. The doping of Ti in Mo-based catalysts reduced the capacity of adsorption for acetylene and also increased the adsorption of hydrogen chloride. Most importantly, the performance of the BTMN excelled those of the individual transition metal nitrides, due to the synergistic activity between Mo and Ti. This will expand the new epoch of the employment of transition metal nitrides as catalysts in the hydrochlorination of acetylene reaction.

  13. Environmentally Friendly Carbon-Preserving Recovery of Noble Metals From Supported Fuel Cell Catalysts.

    Science.gov (United States)

    Latsuzbaia, R; Negro, E; Koper, G J M

    2015-06-08

    The dissolution of noble-metal catalysts under mild and carbon-preserving conditions offers the possibility of in situ regeneration of the catalyst nanoparticles in fuel cells or other applications. Here, we report on the complete dissolution of the fuel cell catalyst, platinum nanoparticles, under very mild conditions at room temperature in 0.1 M HClO4 and 0.1 M HCl by electrochemical potential cycling between 0.5-1.1 V at a scan rate of 50 mV s(-1) . Dissolution rates as high as 22.5 μg cm(-2) per cycle were achieved, which ensured a relatively short dissolution timescale of 3-5 h for a Pt loading of 0.35 mg cm(-2) on carbon. The influence of chloride ions and oxygen in the electrolyte on the dissolution was investigated, and a dissolution mechanism is proposed on the basis of the experimental observations and available literature results. During the dissolution process, the corrosion of the carbon support was minimal, as observed by X-ray photoelectron spectroscopy (XPS). © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Titania–supported silver nanoparticles: An efficient and reusable catalyst for reduction of 4-nitrophenol

    Energy Technology Data Exchange (ETDEWEB)

    Deshmukh, S.P. [Department of Chemistry, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad, Sub-campus Osmanabad 413 501, M.S. (India); Department of Chemistry, D.B.F. Dayanand College of Arts and Science, Solapur 413 001, M.S. (India); Dhokale, R.K. [Department of Chemistry, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad, Sub-campus Osmanabad 413 501, M.S. (India); Yadav, H.M. [Department of Chemistry, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad, Sub-campus Osmanabad 413 501, M.S. (India); Center for Interdisciplinary Research, D.Y. Patil University, Kolhapur 416 005, M.S. (India); Achary, S.N. [Chemistry Division, Bhabha Atomic Research Center, Mumbai 400 085, M.S. (India); Delekar, S.D., E-mail: sddelekar7@rediffmail.com [Department of Chemistry, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad, Sub-campus Osmanabad 413 501, M.S. (India); Department of Chemistry, Shivaji University, Kolhapur 416 001, M.S. (India)

    2013-05-15

    Supported silver nanoparticles were synthesized via in situ sol–gel followed by reduction method with dextrose as reductant and sodium dodecyl sulfate as stabilizer. The synthesized nanoparticles were characterized by X–ray diffraction, transmission electron microscopy, Fourier transform Infra-Red spectroscopy and UV–visible measurements. The XRD peaks confirm the metallic face-centered cubic silver particles. The formation of silver nanoparticles was confirmed from the appearance of surface plasmon absorption maxima at 412 nm; which shifted to the longer wavelengths after supported on titania host lattice. TEM showed the spherical nanoparticles with size in the range of 18–23 nm. An efficient and simple method was reported for the reduction of 4-nitrophenol using titania-supported silver nanoparticles at room temperature. The reaction was first order with respect to the concentration of 4-nitrophenol with higher efficiency. Titania supported silver nanoparticles are reusable and stable heterogeneous catalyst.

  15. Selection of titanium dioxide as support for SCR DeNO{sub x} catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Li, F.; Du, Y.G. [CPI Yuanda Environmental Protection Co. Ltd., Chongqing (China); Zhu, C.B.; Jin, B.S. [Southeast Univ., Nanjing (China). School of Energy and Environment

    2008-07-01

    Over one third of all coal-fired boilers now have flue gas desulfurization capacity in China, controlling sulfur dioxide (SO{sub 2}) pollution to some extent. However, acid-rain remains a problem in China and with the increase in nitrogen oxides (NOx) emission, photo-chemical smog has appeared in many larger cities. It is expected that NOx emissions will surpass SO{sub 2} as the largest contributor to acid rain if controls are not placed on NOx emissions. Some local governments in China are imposing limits on NOx emissions in order to ensure local air quality. Selective catalytic reduction (SCR) technology is widely used in China because of its ability to remove NOx and for its efficiency. This paper examined several types of titanium oxide (TiO{sub 2}) catalysts from different manufacturing processes in China as the potential supporting material for the SCR catalyst. The key to lowering the cost of the SCR catalyst is increase TiO{sub 2} manufacturing technology and production capacity in China. The paper discussed the preparation of particles using a separated impregnation process in the laboratory. The paper also discussed the testing of seven types of TiO{sub 2} powder in the SCR activity measurement device. The characteristics of TiO{sub 2} were also presented focusing on its composition and preparation processes. Methods that were used included the Brunauer, Emmett and Teller method (BET); Fourier transform infrared spectroscopy; X-ray diffraction; and scanning electron microscopy. It was concluded that the sulfate salt contained in the nano-grade anatase TiO{sub 2} powder had an enhancing effect on SCR catalyst performance. As such, it should be retained or added during preparation. 6 refs., 3 tabs., 8 figs.

  16. Hydrodeoxygenation of bio-oil using different mesoporous supports of NiMo catalysts

    Science.gov (United States)

    Rinaldi, Nino; Simanungkalit, Sabar P.; Kristiani, Anis

    2017-11-01

    Biomass as a renewable and sustainable resources need to utilize in many applications, especially for energy application. One of its energy application is about converting biomass into bio-oil. High oxygen content in bio-oil needs to be upgraded through hydrodeoxygenation process before being used as transportation fuel. The development of heterogenenous catalysts become an important aspect in hydrodeoxygenation process, in particular the upgrading process of bio-oil. Several supporting mesoporous materials, such as TiO2, Al2O3 and MCM-41 have unique properties, both physical and chemical properties that can be utilized in various application, including catalyst. These heterogeneous catalysts were modified their catalytic properties by impregnation with some transition metal. The effect of various supporting material and transition metal impregnated were also studied. Their chemical and physical properties were characterized by X-Ray Diffraction, X-Ray Fluororesence, Fourier Transform Infra-Red, and Surface Area Analyzer. The result of characterizations showed that Ni-Mo/TiO2 is more crystalline than Ni-Mo/MCM-41 and Ni-Mo/Al2O3. In other hand, the specific surface area of Ni-Mo/TiO2 is lower than others. These heterogeneous catalysts were tested their catalytic activity in upgrading bio-oil. The liquid products produced were analyzed by using Elemental Analyzer. The result of catalytic activity tests showed catalysts resulted Ni-Mo/TiO2 exhibits best catalytic activity in hydrodeoxygenation process. The oxygen content decreased significantly from 41.61% to 26.22% by using Ni-Mo/TiO2. Compared with Ni-Mo/TiO2, Ni-Mo/MCM-41 and Ni-Mo/Al2O3 decrease lower to 33.22% % and 28.34%, respectively. Ni-Mo/TiO2 also resulted the highest Deoxygenation Degree (DOD) as of 55% compared with Ni-Mo/MCM-41 and Ni-Mo/Al2O3 as of 31.99 % and 47.99%, respectively.

  17. Structurally diverse copper complexes bearing NNO-tridentate Schiff-base derivatives as efficient catalysts for copolymerization of carbon dioxide and cyclohexene oxide.

    Science.gov (United States)

    Tsai, Chen-Yen; Huang, Bor-Hunn; Hsiao, Mon-Wei; Lin, Chu-Chieh; Ko, Bao-Tsan

    2014-05-19

    Structurally diverse copper acetate complexes based on NNO-tridentate Schiff-base ligands were synthesized and characterized as mono-, di-, and trinuclear complexes with respect to varied ancillary ligands. Treatment of the ligand precursors (L(1)-H = 2-(1-((2-(dimethylamino)ethyl)imino)ethyl)-4-methylphenol, L(2)-H = 4-chloro-2-(1-((2-(dimethylamino)ethyl)imino)ethyl)phenol, and L(3)-H = 2-(1-((2-(dimethylamino)ethyl)imino)ethyl)-5-methylphenol) with Cu(OAc)2·H2O (1 equiv) in refluxing ethanol afforded five-coordinate mono- or bimetallic copper complexes ([(L(1))Cu(OAc)(H2O)] (1); [(L(2))Cu(OAc)(H2O)] (2); [(L(3))2Cu2(OAc)2] (3)) in high yields. Dinuclear copper acetate analogue [(L(1))2Cu2(OAc)2] (4) resulted from treatment of L(1)-H as the ligand precursor in refluxing anhydrous MeOH with equimolar proportions of metal acetate salt under a dry nitrogen atmosphere. However, a trinuclear complex, [(L(4))2Cu3(OAc)4] (5), was obtained on utilizing 2-(1-((2-(dimethylamino)ethyl)imino)ethyl)-5-methoxyphenol (L(4)-H) as the proligand under the same synthetic route of 1-3; this complex was also synthesized in the reaction of L(4)-H and copper(II) acetate monohydrate in the ratio of 2:3, giving a quantitative yield. All complexes are active catalysts for copolymerization of cyclohexene oxide (CHO) and CO2 without cocatalysts. In particular, dinuclear Cu complex 3 performed satisfactorily to produce polycarbonates with controllable molecular weights and high carbonate linkages. These copper complexes are the first examples that are effective for both CO2/CHO copolymerization and formation of polymers in a controlled fashion.

  18. Metal (Fe, Co, Ni) supported on different aluminas as Fischer-Tropsch catalyst

    Science.gov (United States)

    Dahlan, Marsih, I. Nyoman; Makertihartha, I. G. B. N.; Praserthdam, Piyasan; Panpranot, Joongjai; Ismunandar

    2015-09-01

    This research aimed to compare the physico-chemical properties of the same metal M (M = iron, cobalt, nickel) supported on aluminas with different morphology and pore size as Fischer-Tropsch catalyst. The aluminas applied as support were alumina synthesized through hydrothermal process, alumina formed by pretreatment of catapal and commercial alumina which named as Ahy, Aca, and Aco respectively. Ahy has uniform morphology of nanotubes while Aca and Aco showed non-uniform morphology of particle lumps. The particle lumps of Aca were larger than those of Aco. Ahy, Aca, and Aco respectively has average pore diameter of 2.75, 2.86 and 2.9 nm. Metals were deposited on the supports by incipient-wetness impregnation method. The catalysts were characterized by XRD, H2-TPR, and H2 chemisorption. Catalyst acitivity test for Fischer-Tropsch reaction was carried out in a micro reactor at 200 °C and 1 atm, and molar ratio of H2/CO = 2:1. The metal oxide particle size increased in the order M/Aco < M/Aca < M/Ahy. The catalysts reducibility also increased according to the order M/Aco < M/Aca < M/Ahy suggesting that the larger metal oxide particles are more reducible. The number of active site was not proportional to the reducibility because during the reduction, larger metal oxide particles were converted into larger metal particles. On the other hand, the number of active sites was inversely proportional to the particle sizes. The number of active site increased in the order M/Ahy < M/Aco < M/Aca. The catalytic activity also increased in the following order M/Ahy < M/Aco < M/Aca. The activity per active site increased according to the order M/Aca < M/Aco < M/Ahy meaning that for M/Ahy, a little increase in active site will lead to a significance increase in catalytic activity. It showed that Ahy has potential for the better support.

  19. Metal (Fe, Co, Ni) supported on different aluminas as Fischer-Tropsch catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Dahlan [Chemistry Education Study Program, Universitas Halu Oleo, Jl. HEA Mokodompit, Kendari 93232 (Indonesia); Marsih, I. Nyoman, E-mail: nyoman@chem.itb.ac.id; Ismunandar [Inorganic and Physical Chemistry Division, Departement of Chemistry, Institut Teknologi Bandung, Jl. Ganesha 10, Bandung 40132 (Indonesia); Makertihartha, I. G. B. N. [Department of Chemical Engineering, Institut Teknologi Bandung, Jl. Ganesha 10, Bandung 40132 (Indonesia); Praserthdam, Piyasan; Panpranot, Joongjai [Center of Excellence on Catalysis and Catalytic Reaction Engineering, Department of Chemical Engineering, Chulalongkorn University, 254 Phayathai Road, Bangkok 10330 (Thailand)

    2015-09-30

    This research aimed to compare the physico-chemical properties of the same metal M (M = iron, cobalt, nickel) supported on aluminas with different morphology and pore size as Fischer-Tropsch catalyst. The aluminas applied as support were alumina synthesized through hydrothermal process, alumina formed by pretreatment of catapal and commercial alumina which named as Ahy, Aca, and Aco respectively. Ahy has uniform morphology of nanotubes while Aca and Aco showed non-uniform morphology of particle lumps. The particle lumps of Aca were larger than those of Aco. Ahy, Aca, and Aco respectively has average pore diameter of 2.75, 2.86 and 2.9 nm. Metals were deposited on the supports by incipient-wetness impregnation method. The catalysts were characterized by XRD, H{sub 2}-TPR, and H{sub 2} chemisorption. Catalyst acitivity test for Fischer-Tropsch reaction was carried out in a micro reactor at 200 °C and 1 atm, and molar ratio of H{sub 2}/CO = 2:1. The metal oxide particle size increased in the order M/Aco < M/Aca < M/Ahy. The catalysts reducibility also increased according to the order M/Aco < M/Aca < M/Ahy suggesting that the larger metal oxide particles are more reducible. The number of active site was not proportional to the reducibility because during the reduction, larger metal oxide particles were converted into larger metal particles. On the other hand, the number of active sites was inversely proportional to the particle sizes. The number of active site increased in the order M/Ahy < M/Aco < M/Aca. The catalytic activity also increased in the following order M/Ahy < M/Aco < M/Aca. The activity per active site increased according to the order M/Aca < M/Aco < M/Ahy meaning that for M/Ahy, a little increase in active site will lead to a significance increase in catalytic activity. It showed that Ahy has potential for the better support.

  20. Activated Carbon Supported Mo-Ti-N Binary Transition Metal Nitride as Catalyst for Acetylene Hydrochlorination

    OpenAIRE

    Hui Dai; Mingyuan Zhu; Haiyang Zhang; Feng Yu; Chao Wang; Bin Dai

    2017-01-01

    Recently, many scientists have focused on the development of green industrial technology. However, the process of synthesizing vinyl chloride faces the problem of Hg pollution. Via a novel approach, we used two elements Mo and Ti to prepare an inexpensive and green binary transition metal nitride (BTMN) as the active ingredient in a catalyst with nano-sized particles and an excellent degree of activation, which was supported on activated carbon. When the Mo/Ti mole ratio was 3:1, the conversi...

  1. Oxygen reduction on carbon supported platinum catalysts in high temperature polymer electrolytes

    DEFF Research Database (Denmark)

    Qingfeng, Li; Bergqvist, R. S.; Hjuler, H. A.

    1999-01-01

    Oxygen reduction on carbon supported platinum catalysts has been investigated in H3PO4, H3PO4-doped Nafion and PBI polymer electrolytes in a temperature range from 80 to 190°C. Compared with pure H3PO4, using the H3PO4 doped Nafion and PBI polymer electrolytes can significantly improve the oxygen...... reduction kinetics. Further enhancement of the catalytic activity can be obtained by operating the polymer electrolytes at higher temperatures. Efforts are being made to develop a polymer electrolyte membrane fuel cell for operation at temperatures between 150 to 200°C....

  2. Oxygen reduction on carbon supported platinum catalysts in high temperature polymer electrolytes

    DEFF Research Database (Denmark)

    Qingfeng, Li; Hjuler, Hans Aage; Bjerrum, Niels

    2000-01-01

    Oxygen reduction on carbon supported platinum catalysts has been investigated in H3PO4, H3PO4-doped Nafion and polybenzimidazole (PBI) polymer electrolytes in a temperature range up to 190 degrees C. Compared with pure H3PO4, the combination of H3PO4 and polymer electrolytes can significantly...... improve the oxygen reduction kinetics due to increased oxygen solubility and suppressed adsorption of phosphoric acid anions. Further enhancement of the catalytic activity can be obtained by operating the polymer electrolytes at higher temperatures. Efforts have been made to develop a polymer electrolyte...

  3. REMOVAL OF COPPER IONS USING ALIQUAT 336/TBP BASED SUPPORTED LIQUID MEMBRANE

    Directory of Open Access Journals (Sweden)

    Baghdad Medjahed

    2014-03-01

    Full Text Available The sorption of copper (II present in an aqueous media using a supported liquid membrane (SLM by chloride tri-N-octylmethylammonium (Aliquat 336 and Tri-n-butylphosphate (TBP from molar ratio 1:1, with polytetrafluoroethylene (PTFE as a membrane support was studied. The effects of various parameters as initial pH, KSCN concentration and ammonium acetate concentration on the extraction yield were carried out. By a calculation program using CHEAQS V. L20.1, the determination of the percentages of the present species before and after extraction were given, in aqueous medium and on the membrane to be able to determine the relation between the nature of the extracted species and the extraction yield. The 23 factorial design achieve the best conditions of recovery procedure. The recovery of copper (II is almost quantitative (94 %, in one step.

  4. Activated Carbon, Carbon Nanofiber and Carbon Nanotube Supported Molybdenum Carbide Catalysts for the Hydrodeoxygenation of Guaiacol

    Directory of Open Access Journals (Sweden)

    Eduardo Santillan-Jimenez

    2015-03-01

    Full Text Available Molybdenum carbide was supported on three types of carbon support—activated carbon; multi-walled carbon nanotubes; and carbon nanofibers—using ammonium molybdate and molybdic acid as Mo precursors. The use of activated carbon as support afforded an X-ray amorphous Mo phase, whereas crystalline molybdenum carbide phases were obtained on carbon nanofibers and, in some cases, on carbon nanotubes. When the resulting catalysts were tested in the hydrodeoxygenation (HDO of guaiacol in dodecane, catechol and phenol were obtained as the main products, although in some instances significant amounts of cyclohexane were produced. The observation of catechol in all reaction mixtures suggests that guaiacol was converted into phenol via sequential demethylation and HDO, although the simultaneous occurrence of a direct demethoxylation pathway cannot be discounted. Catalysts based on carbon nanofibers generally afforded the highest yields of phenol; notably, the only crystalline phase detected in these samples was Mo2C or Mo2C-ζ, suggesting that crystalline Mo2C is particularly selective to phenol. At 350 °C, carbon nanofiber supported Mo2C afforded near quantitative guaiacol conversion, the selectivity to phenol approaching 50%. When guaiacol HDO was performed in the presence of acetic acid and furfural, guaiacol conversion decreased, although the selectivity to both catechol and phenol was increased.

  5. Transesterification of used cooking oil over alkali metal (Li, Na, K supported rice husk silica as potential solid base catalyst

    Directory of Open Access Journals (Sweden)

    Noor Hindryawati

    2014-06-01

    Full Text Available Investigation was conducted on three alkali metals (Li, Na, and K supported by rice husk silica as catalysts for methyl esters production. A simple pseudo-heterogeneous transesterification process of used cooking oil with methanol was conducted to produce methyl esters using calcined alkali metal supported rice husk silica as a solid catalyst. Alkali metal silicate catalysts showed longer lasting activity than the traditional alkali catalysts. The optimum conditions for the process were: alkali metals silicate calcination temperature 500 °C, time 3 h; catalyst amount 3%; methanol to oil molar ratio 9:1; and a reaction temperature of 65 °C. The process was able to transesterify oil to methyl esters in the range of 96.5–98.2% in 1 h for all series. The catalyst is able to tolerant free fatty acid and moisture up to 1.25% and 1.75%, respectively. The catalyst was easily separated from the reaction mixture by filtration and able to reuse six times. The final product met the selected biodiesel fuel properties in accordance with European Standard (EN 14214.

  6. Support Screening Studies on the Hydrogenation of Levulinic Acid to γ-Valerolactone in Water Using Ru Catalysts

    Directory of Open Access Journals (Sweden)

    Anna Piskun

    2016-08-01

    Full Text Available γ-Valerolactone (GVL has been identified as a sustainable platform chemical for the production of carbon-based chemicals. Here we report a screening study on the hydrogenation of levulinic acid (LA to GVL in water using a wide range of ruthenium supported catalysts in a batch set-up (1 wt. % Ru, 90 °C, 45 bar of H2, 2 wt. % catalyst on LA. Eight monometallic catalysts were tested on carbon based(C, carbon nanotubes (CNT and inorganic supports (Al2O3, SiO2, TiO2, ZrO2, Nb2O5 and Beta-12.5. The best result was found for Ru/Beta-12.5 with almost quantitative LA conversion (94% and 66% of GVL yield after 2 h reaction. The remaining product was 4-hydroxypentanoic acid (4-HPA. Catalytic activity for a bimetallic RuPd/TiO2 catalyst was by far lower than for the monometallic Ru catalyst (9% conversion after 2 h. The effects of relevant catalyst properties (average Ru nanoparticle size, Brunauer-Emmett-Teller (BET surface area, micropore area and total acidity on catalyst activity were assessed.

  7. A combined in situ XAS-XRPD-Raman study of Fischer-Tropsch synthesis over a carbon supported Co catalyst

    DEFF Research Database (Denmark)

    Tsakoumis, Nikolaos E.; Dehghan, Roya; Johnsen, Rune

    2013-01-01

    A cobalt based Fischer-Tropsch synthesis (FTS) catalyst, supported on a carbon nanofibers/carbon felt composite (Co/CNF/CF) was studied in situ at realistic conditions. The catalyst was monitored by Xray absorption spectroscopy (XAS), high-resolution X-ray powder diffraction (HR-XRPD) and Raman...... to reduce further at the induction period of FTS, while crystallite growth is been detected in the same period. At steady state FTS the amount of metallic Co is constant. A change in the volumetric flow towards higher conversions did not affect the degree of reduction or the crystallite size of the catalyst...

  8. Comparison of Catalysts Preyssler and Silica-Supported Nano Preyssler in the Synthesis of Acetyl Salicylic Acid

    Directory of Open Access Journals (Sweden)

    H. Nazari

    2012-01-01

    Full Text Available The extensive demand for cleaner environment is forcing chemical industry to use less hazardous materials. In this regard, heteropolyacids attracted considerable amount of interest due to the less toxic behavior in addition of possessing higher acidity. Heteropoly acids have been used as catalysts for the reaction of salicylic acid with acetic anhydride. The performance of different forms of heteropoly acids in the presence of acetic anhydride as acetylating agent for acetylation of salicylic acid was compared. The best conditions were observed using Preyssler and Silica-supported Preyssler Nanoparticles as catalysts. The catalyst is recyclable and reusable.

  9. Development of Cu and Ni catalysts supported on ZrO{sub 2} for the generation of H{sub 2} by means of the reaction of reformed methanol in atmosphere oxidizer; Desarrollo de catalizadores de Cu y Ni soportados en ZrO{sub 2} para la generacion de H{sub 2} mediante la reaccion de reformado de metanol en atmosfera oxidante

    Energy Technology Data Exchange (ETDEWEB)

    Lopez C, P.

    2012-07-01

    ZrO{sub 2} was prepared by the sol-gel method and calcined at 450 C. The prepared zirconia was impregnated with an aqueous solution of Cu(CH{sub 3}CO{sub 2}){sub 2}{center_dot}H{sub 2}O or NiNO{sub 3}{center_dot}6H{sub 2}O at an appropriate concentration to yield 3 wt % of copper or nickel, respectively, in the mono metallic catalysts. Three bimetallic samples were prepared at 80% Cu and 20% Ni respectively to obtain 3 wt % of total metallic phase. Surface area of the Cu-Ni base catalysts supported on ZrO{sub 2} oxide showed differences as a function of the metal addition. Between them, the Cu/ZrO{sub 2} catalyst had the lowest surface area than other catalysts. X-ray diffraction patterns of the bimetallic catalysts did not show diffraction peaks of the Cu, Ni or bimetallic Cu-Ni alloys. In addition, TPR profiles of the bimetallic catalysts had the lowest reduction temperature compared with the mono metallic samples. The reactivity of the catalysts in the range of 250-350 C showed that the samples prepared by successive impregnation had the highest catalytic activity than the other catalysts studied. Also the selectivity for H{sub 2} production was higher for these catalysts. This finding was associated to the presence of the bimetallic Cu-Ni nanoparticles, as was evidenced by Tem-EDX analysis. (Author)

  10. Continuous preparation of carbon-nanotube-supported platinum catalysts in a flow reactor directly heated by electric current

    Directory of Open Access Journals (Sweden)

    Alicja Schlange

    2011-10-01

    Full Text Available In this contribution we present for the first time a continuous process for the production of highly active Pt catalysts supported by carbon nanotubes by use of an electrically heated tubular reactor. The synthesized catalysts show a high degree of dispersion and narrow distributions of cluster sizes. In comparison to catalysts synthesized by the conventional oil-bath method a significantly higher electrocatalytic activity was reached, which can be attributed to the higher metal loading and smaller and more uniformly distributed Pt particles on the carbon support. Our approach introduces a simple, time-saving and cost-efficient method for fuel cell catalyst preparation in a flow reactor which could be used at a large scale.

  11. Investigation of PCDD/F emissions from mobile source diesel engines: impact of copper zeolite SCR catalysts and exhaust aftertreatment configurations.

    Science.gov (United States)

    Liu, Z Gerald; Wall, John C; Barge, Patrick; Dettmann, Melissa E; Ottinger, Nathan A

    2011-04-01

    This study investigated the impact of copper zeolite selective catalytic reduction (SCR) catalysts and exhaust aftertreatment configurations on the emissions of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) from mobile source diesel engines. Emissions of PCDD/Fs, reported as the weighted sum of 17 congeners called the toxic equivalency quotient (TEQ), were measured using a modified EPA Method 0023A in the absence and presence of exhaust aftertreatment. Engine-out emissions were measured as a reference, while aftertreatment configurations included various combinations of diesel oxidation catalyst (DOC), diesel particulate filter (DPF), Cu-zeolite SCR, Fe-zeolite SCR, ammonia oxidation catalyst (AMOX), and aqueous urea dosing. In addition, different chlorine concentrations were evaluated. Results showed that all aftertreatment configurations reduced PCDD/F emissions in comparison to the engine-out reference, consistent with reduction mechanisms such as thermal decomposition or combined trapping and hydrogenolysis reported in the literature. Similarly low PCDD/F emissions from the DOC-DPF and the DOC-DPF-SCR configurations indicated that PCDD/F reduction primarily occurred in the DOC-DPF with no noticeable contribution from either the Cu- or Fe-zeolite SCR systems. Furthermore, experiments performed with high chlorine concentration provided no evidence that chlorine content has an impact on the catalytic synthesis of PCDD/Fs for the chlorine levels investigated in this study.

  12. Size and Promoter Effects on Stability of Carbon-Nanofiber-Supported Iron-Based Fischer-Tropsch Catalysts.

    Science.gov (United States)

    Xie, Jingxiu; Torres Galvis, Hirsa M; Koeken, Ard C J; Kirilin, Alexey; Dugulan, A Iulian; Ruitenbeek, Matthijs; de Jong, Krijn P

    2016-06-03

    The Fischer-Tropsch Synthesis converts synthesis gas from alternative carbon resources, including natural gas, coal, and biomass, to hydrocarbons used as fuels or chemicals. In particular, iron-based catalysts at elevated temperatures favor the selective production of C2-C4 olefins, which are important building blocks for the chemical industry. Bulk iron catalysts (with promoters) were conventionally used, but these deactivate due to either phase transformation or carbon deposition resulting in disintegration of the catalyst particles. For supported iron catalysts, iron particle growth may result in loss of catalytic activity over time. In this work, the effects of promoters and particle size on the stability of supported iron nanoparticles (initial sizes of 3-9 nm) were investigated at industrially relevant conditions (340 °C, 20 bar, H2/CO = 1). Upon addition of sodium and sulfur promoters to iron nanoparticles supported on carbon nanofibers, initial catalytic activities were high, but substantial deactivation was observed over a period of 100 h. In situ Mössbauer spectroscopy revealed that after 20 h time-on-stream, promoted catalysts attained 100% carbidization, whereas for unpromoted catalysts, this was around 25%. In situ carbon deposition studies were carried out using a tapered element oscillating microbalance (TEOM). No carbon laydown was detected for the unpromoted catalysts, whereas for promoted catalysts, carbon deposition occurred mainly over the first 4 h and thus did not play a pivotal role in deactivation over 100 h. Instead, the loss of catalytic activity coincided with the increase in Fe particle size to 20-50 nm, thereby supporting the proposal that the loss of active Fe surface area was the main cause of deactivation.

  13. Size and Promoter Effects on Stability of Carbon-Nanofiber-Supported Iron-Based Fischer–Tropsch Catalysts

    Science.gov (United States)

    2016-01-01

    The Fischer–Tropsch Synthesis converts synthesis gas from alternative carbon resources, including natural gas, coal, and biomass, to hydrocarbons used as fuels or chemicals. In particular, iron-based catalysts at elevated temperatures favor the selective production of C2–C4 olefins, which are important building blocks for the chemical industry. Bulk iron catalysts (with promoters) were conventionally used, but these deactivate due to either phase transformation or carbon deposition resulting in disintegration of the catalyst particles. For supported iron catalysts, iron particle growth may result in loss of catalytic activity over time. In this work, the effects of promoters and particle size on the stability of supported iron nanoparticles (initial sizes of 3–9 nm) were investigated at industrially relevant conditions (340 °C, 20 bar, H2/CO = 1). Upon addition of sodium and sulfur promoters to iron nanoparticles supported on carbon nanofibers, initial catalytic activities were high, but substantial deactivation was observed over a period of 100 h. In situ Mössbauer spectroscopy revealed that after 20 h time-on-stream, promoted catalysts attained 100% carbidization, whereas for unpromoted catalysts, this was around 25%. In situ carbon deposition studies were carried out using a tapered element oscillating microbalance (TEOM). No carbon laydown was detected for the unpromoted catalysts, whereas for promoted catalysts, carbon deposition occurred mainly over the first 4 h and thus did not play a pivotal role in deactivation over 100 h. Instead, the loss of catalytic activity coincided with the increase in Fe particle size to 20–50 nm, thereby supporting the proposal that the loss of active Fe surface area was the main cause of deactivation. PMID:27330847

  14. Alumina-Supported Manganese Catalysts for Soot Combustion Prepared by Thermal Decomposition of KMnO4

    Directory of Open Access Journals (Sweden)

    Agustin Bueno-López

    2012-09-01

    Full Text Available Alumina-supported manganese catalysts with cryptomelane and/or birnessite structure have been prepared using a simple method based on the thermal decomposition of potassium permanganate. The samples have been characterized by XRD, FTIR, TGA, DSC, N2 adsorption at −196 °C, SEM, H2-TPR and XPS, and their catalytic activity for soot combustion has been tested and compared to that of a reference Pt/alumina catalyst. The thermal decomposition of alumina-supported KMnO4 yields a mixture of supported birnessite and potassium manganate which is the most effective, among those prepared, to lower the soot combustion temperature. However, this material is not useful for soot combustion because the accelerating effect is not based on a catalytic process but on the oxidation of soot by potassium manganate. A suitable soot combustion catalyst is obtained after potassium manganate is removed by water washing, yielding only the birnessite phase on the γ-Al2O3 support. This birnessite phase can be transformed into cryptomelane by calcination at 600 °C. These two samples, γ-Al2O3-supported birnessite and cryptomelane are suitable catalysts for soot combustion in NOx/O2 mixtures, as their catalytic activity is based on the NO2-assited mechanism, that is, both catalysts accelerate the oxidation of NO to NO2 and NO2 promotes soot oxidation. The soot combustion temperatures obtained with these birnessite/cryptomelane alumina-supported catalysts are similar to that obtained with the reference Pt/alumina catalyst.

  15. Lanthanum cobaltite perovskite supported on zirconia as an efficient heterogeneous catalyst for activating Oxone in water.

    Science.gov (United States)

    Lin, Kun-Yi Andrew; Chen, Yu-Chien; Lin, Tien-Yu; Yang, Hongta

    2017-07-01

    Zirconia-supported LaCoO3 perovskite (LaCoO3/ZrO2 (LCZ)) is prepared and adopted for the first time as a heterogeneous catalyst for activating Oxone to degrade organic pollutants. The resulting LCZ exhibits a significantly higher surface area (i.e., 10 times) than bulk LaCoO3 powder as nanoscale LaCoO3 particles were easily afforded on the surface of ZrO2 support. As Rhodamine B (RB) decolorization is selected as a model test to evaluate catalytic activity for activating Oxone, LCZ showed a much higher catalytic activity to activate Oxone than LaCoO3 even though LCZ contained only 12.5wt% of LaCoO3. LCZ-activated Oxone also remained effective for RB decolorization even in the presence of salts and other organic contaminant. The mechanism of RB decolorization by LCZ-activated Oxone was revealed and involved sulfate radical and other reactive oxygen species. The mechanism of Oxone activation by LCZ could be owing to both La3+ and Co3+ of LCZ. LCZ was recycled to activate Oxone for RB decolorization over multiple times without loss of catalytic activity. These results demonstrate that LCZ is a promising LaCoO3-based nanocomposite as a heterogeneous catalyst for activating Oxone to degrade organic pollutants. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Oxygen Reduction Reaction Activity and Durability of Pt Catalysts Supported on Titanium Carbide

    Directory of Open Access Journals (Sweden)

    Morio Chiwata

    2015-06-01

    Full Text Available We have prepared Pt nanoparticles supported on titanium carbide (TiC (Pt/TiC as an alternative cathode catalyst with high durability at high potentials for polymer electrolyte fuel cells. The Pt/TiC catalysts with and without heat treatment were characterized by X-ray diffraction (XRD, X-ray photoelectron spectroscopy (XPS, and transmission electron microscopy (TEM. Hemispherical Pt nanocrystals were found to be dispersed uniformly on the TiC support after heat treatment at 600 °C in 1% H2/N2 (Pt/TiC-600 °C. The electrochemical properties (cyclic voltammetry, electrochemically active area (ECA, and oxygen reduction reaction (ORR activity of Pt/TiC-600 °C and a commercial Pt/carbon black (c-Pt/CB were evaluated by the rotating disk electrode (RDE technique in 0.1 M HClO4 solution at 25 °C. It was found that the kinetically controlled mass activity for the ORR on Pt/TiC-600 °C at 0.85 V (507 A g−1 was comparable to that of c-Pt/CB (527 A g−1. Moreover, the durability of Pt/TiC-600 °C examined by a standard potential step protocol (E = 0.9 V↔1.3 V vs. RHE, holding 30 s at each E was much higher than that for c-Pt/CB.

  17. Reduction of Furfural to Furfuryl Alcohol in Liquid Phase over a Biochar-Supported Platinum Catalyst

    Directory of Open Access Journals (Sweden)

    Ariadna Fuente-Hernández

    2017-02-01

    Full Text Available In this work, the liquid phase hydrogenation of furfural has been studied using a biochar-supported platinum catalyst in a batch reactor. Reactions were performed between 170 °C and 320 °C, using 3 wt % and 5 wt % of Pt supported on a maple-based biochar under hydrogen pressure varying from 500 psi to 1500 psi for reaction times between 1 h and 6 h in various solvents. Under all reactive conditions, furfural conversion was significant, whilst under specific conditions furfuryl alcohol (FA was obtained in most cases as the main product showing a selectivity around 80%. Other products as methylfuran (MF, furan, and trace of tetrahydrofuran (THF were detected. Results showed that the most efficient reaction conditions involved a 3% Pt load on biochar and operations for 2 h at 210 °C and 1500 psi using toluene as solvent. When used repetitively, the catalyst showed deactivation although only a slight variation in selectivity toward FA at the optimal experimental conditions was observed.

  18. Metal–Organic Framework Supported Cobalt Catalysts for the Oxidative Dehydrogenation of Propane at Low Temperature

    Science.gov (United States)

    2016-01-01

    Zr-based metal–organic frameworks (MOFs) have been shown to be excellent catalyst supports in heterogeneous catalysis due to their exceptional stability. Additionally, their crystalline nature affords the opportunity for molecular level characterization of both the support and the catalytically active site, facilitating mechanistic investigations of the catalytic process. We describe herein the installation of Co(II) ions to the Zr6 nodes of the mesoporous MOF, NU-1000, via two distinct routes, namely, solvothermal deposition in a MOF (SIM) and atomic layer deposition in a MOF (AIM), denoted as Co-SIM+NU-1000 and Co-AIM+NU-1000, respectively. The location of the deposited Co species in the two materials is determined via difference envelope density (DED) analysis. Upon activation in a flow of O2 at 230 °C, both materials catalyze the oxidative dehydrogenation (ODH) of propane to propene under mild conditions. Catalytic activity as well as propene selectivity of these two catalysts, however, is different under the same experimental conditions due to differences in the Co species generated in these two materials upon activation as observed by in situ X-ray absorption spectroscopy. A potential reaction mechanism for the propane ODH process catalyzed by Co-SIM+NU-1000 is proposed, yielding a low activation energy barrier which is in accord with the observed catalytic activity at low temperature. PMID:28149950

  19. Metal-Organic Framework Supported Cobalt Catalysts for the Oxidative Dehydrogenation of Propane at Low Temperature.

    Science.gov (United States)

    Li, Zhanyong; Peters, Aaron W; Bernales, Varinia; Ortuño, Manuel A; Schweitzer, Neil M; DeStefano, Matthew R; Gallington, Leighanne C; Platero-Prats, Ana E; Chapman, Karena W; Cramer, Christopher J; Gagliardi, Laura; Hupp, Joseph T; Farha, Omar K

    2017-01-25

    Zr-based metal-organic frameworks (MOFs) have been shown to be excellent catalyst supports in heterogeneous catalysis due to their exceptional stability. Additionally, their crystalline nature affords the opportunity for molecular level characterization of both the support and the catalytically active site, facilitating mechanistic investigations of the catalytic process. We describe herein the installation of Co(II) ions to the Zr6 nodes of the mesoporous MOF, NU-1000, via two distinct routes, namely, solvothermal deposition in a MOF (SIM) and atomic layer deposition in a MOF (AIM), denoted as Co-SIM+NU-1000 and Co-AIM+NU-1000, respectively. The location of the deposited Co species in the two materials is determined via difference envelope density (DED) analysis. Upon activation in a flow of O2 at 230 °C, both materials catalyze the oxidative dehydrogenation (ODH) of propane to propene under mild conditions. Catalytic activity as well as propene selectivity of these two catalysts, however, is different under the same experimental conditions due to differences in the Co species generated in these two materials upon activation as observed by in situ X-ray absorption spectroscopy. A potential reaction mechanism for the propane ODH process catalyzed by Co-SIM+NU-1000 is proposed, yielding a low activation energy barrier which is in accord with the observed catalytic activity at low temperature.

  20. Influence of surface morphology on methanol oxidation at a glassy carbon-supported Pt catalyst

    Directory of Open Access Journals (Sweden)

    S. STEVANOVIC

    2008-08-01

    Full Text Available Platinum supported on glassy carbon (GC was used as a model system for studying the influence of the surface morphology of a Pt catalyst on methanol oxidation in alkaline and acidic solutions. Platinum was deposited by the potential step method on GC samples from H2SO4 + H2PtCl6 solution under the same conditions with loadings from 10 to 80 mg cm-2. AFM and STM images of the GC/Pt electrodes showed that the Pt was deposited in the form of 3D agglomerates composed of spherical particles. Longer deposition times resulted in increased growth of Pt forms and a decrease in the specific area of the Pt. The real surface area of Pt increased with loading but the changes were almost negligible at higher loadings. Nevertheless, both the specific and mass activity of platinum supported on glassy carbon for methanol oxidation in acidic and in alkaline solutions exhibit a volcanic dependence with respect to the platinum loading. The increase in the activity can be explained by the increasing the particle size with the loading and thus an increase in the contiguous Pt sites available for adsorption and decomposition of methanol. However, the decrease in the activity of the catalyst with further increase of loading and particle size after reaching the maximum is related to the decrease of active sites available for methanol adsorption and their accessibility as a result of more close proximity and pronounced coalescence of the Pt particles.

  1. Quantification of zinc atoms in a surface alloy on copper in an industrial-type methanol synthesis catalyst

    DEFF Research Database (Denmark)

    Kuld, Sebastian; Moses, Poul Georg; Sehested, Jens

    2014-01-01

    Methanol has recently attracted renewed interest because of its potential importance as a solar fuel. Methanol is also an important bulk chemical that is most efficiently formed over the industrial Cu/ZnO/Al2O3 catalyst. The identity of the active site and, in particular, the role of Zn......O as a promoter for this type of catalyst is still under intense debate. Structural changes that are strongly dependent on the pretreatment method have now been observed for an industrial-type methanol synthesis catalyst. A combination of chemisorption, reaction, and spectroscopic techniques provides a consistent...

  2. Quantification of zinc atoms in a surface alloy on copper in an industrial-type methanol synthesis catalyst

    DEFF Research Database (Denmark)

    Kuld, Sebastian; Moses, Poul Georg; Sehested, Jens

    2014-01-01

    Methanol has recently attracted renewed interest because of its potential importance as a solar fuel.1 Methanol is also an important bulk chemical that is most efficiently formed over the industrial Cu/ZnO/Al2O3 catalyst. The identity of the active site and, in particular, the role of Zn......O as a promoter for this type of catalyst is still under intense debate.2 Structural changes that are strongly dependent on the pretreatment method have now been observed for an industrial-type methanol synthesis catalyst. A combination of chemisorption, reaction, and spectroscopic techniques provides...

  3. Preparation, surface characterization and performance of a Fischer-Tropsch catalyst of cobalt supported on silica nanosprings

    Science.gov (United States)

    Kengne, Blaise-Alexis Fouetio; Alayat, Abdulbaset M.; Luo, Guanqun; McDonald, Armando G.; Brown, Justin; Smotherman, Hayden; McIlroy, David N.

    2015-12-01

    The reduction of cobalt (Co) catalyst supported on silica nanosprings for Fischer-Tropsch synthesis (FTS) has been monitored by X-ray photoelectron spectroscopy (XPS) and compared to FT catalytic activity. The cobalt is present in the starting catalyst as a Co3O4 spinel phase. A two-step reduction of Co3O4 to CoO and then to Co0 is observed, which is consistent with the results of H2-temperature programmed reduction. During the reduction the two steps occur concurrently. The deconvolution of the Co 2p core level state for the catalyst reduced at 385 °C and 1.0 × 10-6 Torr of H2 revealed signatures of Co0, CoO, and Co3O4. The reduction saturates at a Coo concentration of approximately 41% after 20 h, which correlates with the activity and lifetime of the catalyst during FTS testing. Conversely, at 680 °C and 10 Torr of H2, the catalyst is completely reduced after 10 h. The evolution of the Co d-band at the Fermi level in the valence band XPS spectrum definitively verifies the metallic phase of Co. FTS evaluation of the Co/NS catalyst reduced at 609 °C showed higher production rate (3-fold) of C6-C17 hydrocarbons than the catalyst reduced at 409 °C and is consistent with the XPS analysis.

  4. Production of a Biofuel that Keeps the Glycerol as a Monoglyceride by Using Supported KF as Heterogeneous Catalyst

    Directory of Open Access Journals (Sweden)

    Juan Calero

    2014-06-01

    Full Text Available This study describes the results obtained in the synthesis of a biofuel that avoids the production of glycerol by applying supported KF as alkaline heterogeneous catalyst, to generate two moles of fatty acid methyl esters and one mole of monoglyceride from one mol of triglyceride. In this respect, the selective transesterification process of sunflower oil with methanol was carried out with KF (10 wt% supported on three different solids, Al2O3, ZnO and MgO. The standard experimental conditions employed in the heterogeneous selective methanolysis reaction were: 12 mL of sunflower oil, 2.7 mL of methanol, 0.8 g of catalyst, at 65 °C temperature and one hour of reaction time. In all cases 100% conversion was obtained, with high selectivity values, greater than 90%, and quite suitable viscosity values, 4.5–8.5 cSt. In this way, the best catalytic behavior in the first use was obtained by using Al2O3 as support. However, although in the five consecutive reuses all catalysts exhibited a continuous decrease in their catalytic activities; the lower one was for KF catalyst using MgO as support. In summary, these three KF supported catalysts are very suitable to obtain a new biofuel, similar to conventional biodiesel, applicable to diesel engines.

  5. Sulfur resistance of methanol synthesis from syngas over metal-supported catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Ma Yu-chun; Ge Qing-jie; Xu Heng-yong; Li Wen-zhao [Chinese Academy of Sciences, Dalian (China). Laboratory of Applied Catalysis

    2009-08-15

    Supported metal catalysts for methanol synthesis from syngas was prepared by co-precipitation method and its sulfur resistance was studied. The experimental results show that Cu/ZnO exhibited the best methanol synthesis activity but deactivated quickly when sulfur-contaminated syngas was used. However, Pd/CeO{sub 2} showed stable methanol synthesis activity in the sulfur-contaminated syngas. The characterization results indicate that the active components of Cu/ZnO reacted with H{sub 2}S in syngas and deactivated the methanol synthesis catalayst. CeO{sub 2} as support of Pd/CeO{sub 2} could first react with H{sub 2}S in syngas and protected the metal active components, and further kept the stable methanol synthesis activity in the sulfur-contaminated syngas. 24 refs., 3 figs., 1 tab.

  6. Surface tailored single walled carbon nanotubes as catalyst support for direct methanol fuel cell

    Science.gov (United States)

    Kireeti, Kota V. M. K.; Jha, Neetu

    2017-10-01

    A strategy for tuning the surface property of Single Walled Carbon Nanotubes (SWNTs) for enhanced methanol oxidation reaction (MOR) and oxygen reduction reaction (ORR) along with methanol tolerance is presented. The surface functionality is tailored using controlled acid and base treatment. Acid treatment leads to the attachment of carboxylic carbon (CC) fragments to SWNT making it hydrophilic (P3-SWNT). Base treatment of P3-SWNT with 0.05 M NaOH reduces the CCs and makes it hydrophobic (P33-SWNT). Pt catalyst supported on the P3-SWNT possesses enhanced MOR whereas that supported on P33-SWNT not only enhances ORR kinetics but also possess good tolerance towards methanol oxidation as verified by the electrochemical technique.

  7. Preparation of MgO supported platinum nanoparticle catalyst using toluene dispersed platinum sol

    Science.gov (United States)

    Seth, Jhumur; Nepak, Devadutta; Chaudhari, Vijay R.; Prasad, Bhagavatula L. V.

    2017-10-01

    An effective way of anchoring Pt nanoparticles on MgO using toluene dispersed platinum nanoparticles (Pt-NPs) as one of the ingredient is demonstrated. The usage of particles dispersed in toluene allows the retention of size and size distribution of preformed Pt-NPs even after deposition on MgO support with high active surface area, which is crucial for heterogeneous catalysis. The catalyst thus prepared, displayed selective hydrogenation of cinnamaldehyde to cinnamyl alcohol with high turn on frequency (TOF - 105 h-1) with respect to the total Pt content. We attribute this efficient catalytic performance to the uniform distribution and deposition of Pt on the active MgO support and its better accessible surface as evidenced by the cyclic-voltammetry results.

  8. Gas-phase hydrogenation/hydrogenolysis of phenol over supported nickel catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Shin, E.J.; Keane, M.A.

    2000-04-01

    The gas-phase hydrogenation/hydrogenolysis of alcoholic solutions of phenol between 423 and 573 K has been studied using a Y zeolite-supported nickel catalyst (2.2% w/w Ni) and Ni/SiO{sub 2} catalysts (1.5--20.3% w/w Ni). This is a viable means of treating concentrated phenol streams to generate recyclable raw material. Phenol hydrogenation proceeded in a stepwise fashion with cyclohexanone as a reactive intermediate while a combination of hydrogenolysis and hydrogenation yielded cyclohexane. Hydrogenolysis to benzene is favored by high nickel loadings and elevated temperatures. A catalytic hydrogen treatment of cyclohexanone and cyclohexanol helped to establish the overall reaction network/mechanism. The possible role of thermodynamic limitations is considered and structure sensitivity is addressed; reaction data are subjected to a pseudo-first-order kinetic treatment. Hydrogen temperature-programmed desorption (H{sub 2}-TPD) has revealed the existence of different forms of surface hydrogen. Selectivity is interpreted on the basis of the H{sub 2}-TPD profiles and the possible phenol/catalyst interactions. The zeolite sample only catalyzed (via the surface Bronsted acidity) anisole formation in the presence of methanol, but this was suppressed when hexanol was used; the zeolite then promoted hydrogenolysis. The zeolite, however, deactivated and this was not reversed by heating in hydrogen. The results of the hydrogen treatment of aqueous rather than alcoholic phenol solutions are presented, where a switch from methanol to water was accompanied by a move from highly selective hydrogenolysis to highly selective hydrogenation.

  9. Synthesis of catalysts supported in {gamma}-alumina; Sintese de catalisadores suportados na {gamma}-alumina

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Luiza Gabriel; Silva, A.J.N.; Santos, I.M.G.; Souza, A.G. [Paraiba Univ, Joao Pessoa, PB (Brazil). Dept. de Quimica. Lab. de Termoquimica e Materiais]. E-mail: luizagaby@yahoo.com.br; Fernandes Junior, V.J.; Araujo, A.S. [Rio Grande do Norte Univ., Natal, RN (Brazil). Dept. de Quimica. Lab. de Combustiveis

    2003-07-01

    Fuels contain a great amount of undesirable pollutants as asphaltenes, metals, sulfides and nitrogen compounds. The content of sulfur in petroleum is around 1%,. When burned, fuels liberate SO{sub x}, the greatest air pollutant . The maximum sulfur quantity in diesel is {approx}350 wppm, but in agreement to European specifications, this content will fall to 50 wppm up to 2005. To remove this sulfur a deep hydrodesulfurization is necessary, requiring high performance catalysts. This way, in this work, the following catalysts were synthesized, using Pechini method: MoO{sub 3} containing Ni and/or Co supported on {gamma}-alumina, with the formulas Co{sub x}Mo{sub 1-x}O{sub 3}/Al{sub 2}O{sub 3}, Ni{sub x}Mo{sub 1-x}O{sub 3}/Al{sub 2}O{sub 3} and Ni{sub x/2}Co{sub x/2}Mo{sub 1-x}O{sub 3}/Al{sub 2}O{sub 3} where x 0,01, 0,02 and 0,03 in mol percentage. This method was proposed, due to its high stoichiometry control, purity, reproducibility and homogeneity. All catalysts were submitted to thermal treatment at 500 deg C to 700 deg C and characterized by thermogravimetry, infrared spectroscopy, X-ray diffraction. Results indicate the stabilization of the requested composition at around 622 deg C. The X-ray diffraction results indicate that secondary phase increases with dopant amount. (author)

  10. Reactivity of a Carbon-Supported Single-Site Molybdenum Dioxo Catalyst for Biodiesel Synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Mouat, Aidan R.; Lohr, Tracy L.; Wegener, Evan C.; Miller, Jeffrey T.; Delferro, Massimiliano; Stair, Peter C.; Marks, Tobin J.

    2016-08-23

    A single-site molybdenum dioxo catalyst, (Oc)2Mo(=O)2@C, was prepared via direct grafting of MoO2Cl2(dme) (dme = 1,2-dimethoxyethane) on high-surface- area activated carbon. The physicochemical and chemical properties of this catalyst were fully characterized by N2 physisorption, ICP-AES/OES, PXRD, STEM, XPS, XAS, temperature-programmed reduction with H2 (TPR-H2), and temperature-programmed NH3 desorption (TPD-NH3). The single-site nature of the Mo species is corroborated by XPS and TPR-H2 data, and it exhibits the lowest reported MoOx Tmax of reduction reported to date, suggesting a highly reactive MoVI center. (Oc)2Mo(=O)2@C catalyzes the transesterification of a variety of esters and triglycerides with ethanol, exhibiting high activity at moderate temperatures (60-90 °C) and with negligible deactivation. (Oc)2Mo(=O)2@C is resistant to water and can be recycled at least three times with no loss of activity. The transesterification reaction is determined experimentally to be first order in [ethanol] and first order in [Mo] with ΔH = 10.5(8) kcal mol-1 and ΔS = -32(2) eu. The low energy of activation is consistent with the moderate conditions needed to achieve rapid turnover. This highly active carbon-supported single-site molybdenum dioxo species is thus an efficient, robust, and lowcost catalyst with significant potential for transesterification processes.

  11. Ethylenediamine-modified multiwall carbon nanotubes as a Pt catalyst support

    Energy Technology Data Exchange (ETDEWEB)

    Vukovic, Goran D. [Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11120 Belgrade (Serbia); Obradovic, Maja D. [Institute of Chemistry, Technology and Metallurgy, University of Belgrade, Njegoseva 12, 11001 Belgrade (Serbia); Marinkovic, Aleksandar D.; Rogan, Jelena R.; Uskokovic, Petar S. [Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11120 Belgrade (Serbia); Radmilovic, Velimir R. [Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11120 Belgrade (Serbia); National Center for Electron Microscopy, Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720 (United States); Gojkovic, Snezana Lj., E-mail: sgojkovic@tmf.bg.ac.rs [Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11120 Belgrade (Serbia)

    2011-10-17

    Highlights: {yields} Multi-walled carbon nanotubes (MWCNTs) were used as a support for Pt nanoparticles. {yields} Modification of oxidized MWCNTs by ethylenediamine is necessary for high Pt loading. {yields} Pt nanoparticles are homogenously distributed on the support without agglomeration. {yields} The activity of the catalyst for oxygen reduction matches the commercial catalyst. - Abstract: Multi-walled carbon nanotubes (MWCNTs) were used as a support for Pt nanoparticles prepared by the microwave-assisted polyol method. The MWCNTs were pretreated by chemical oxidation (o-MWCNTs) followed by modification by ethylenediamine (eda-MWCNTs). Characterization of both oxidized and eda-modified materials by UV-spectroscopy, cyclic voltammetry and electrochemical impedance spectroscopy revealed that the modification by eda leads to (i) agglomeration of the MWCNTs, (ii) a decrease in the capacitance of the material and (iii) reduced rate of electron transfer between the MWCNTs and solution species. However, the Pt loading of Pt/o-MWCNTs was only 2 mass% while the loading of Pt/eda-MWCNTs was 20 mass%. Much higher efficiency of Pt deposition on eda-MWCNTs than on o-MWCNTs was ascribed to the shift in pH{sub pzc} value of the MWCNT surface from 2.43 to 5.91 upon modification by eda. Transmission electron microscopy revealed that the mean diameter of the Pt particles in Pt/eda-MWCNTs is 2.5 {+-} 0.5 nm and that their distribution on the support is homogenous with no evidence of pronounced particle agglomeration. Cyclic voltammetry of a Pt/eda-MWCNT thin film indicated a clean Pt surface with well-resolved peaks characteristic of polycrystalline Pt. Its electrocatalytic activity for oxygen reduction was examined and the results corresponded to the commercial Pt nanocatalyst. This study shows that modification of o-MWCNTs by eda helps to achieve homogenous distribution of small Pt nanoparticles and does not impede its electrocatalytic activity.

  12. SUPPORTED LIQUID CATALYSTS FOR REMOVAL OF HIGH TEMPERATURE FUEL CELL CONTAMINANTS

    Energy Technology Data Exchange (ETDEWEB)

    Alan W. Weimer (PI); Peter Czerpak; Patrick Hilbert

    2000-01-01

    A novel catalytic synthesis gas oxidation process using molten carbonate salts supported on compatible fluidized iron oxide particles (supported-liquid-phase-catalyst (SLPC) fluidized bed process) was investigated. This process combines the advantages of large scale fluidized bed processing with molten salt bath oxidation. Molten salt catalysts can be supported within porous fluidized particles in order to improve mass transfer rates between the liquid catalysts and the reactant gases. Synthesis gas can be oxidized at reduced temperatures resulting in low NO{sub x} formation while trace sulfides and halides are captured in-situ. Hence, catalytic oxidation of synthesis gas can be carried out simultaneously with hot gas cleanup. Such SLPC fluidized bed processes are affected by inter-particle liquid capillary forces that may lead to agglomeration and de-fluidization of the bed. An understanding of the origin and strength of these forces is needed so that they can be overcome in practice. Process design is based on thermodynamic free energy minimization calculations that indicate the suitability of eutectic Na{sub 2}CO{sub 3}/K{sub 2}CO{sub 3} mixtures for capturing trace impurities in-situ (< 1 ppm SO{sub x} released) while minimizing the formation of NO{sub x}(< 10 ppm). Iron oxide has been identified as a preferred support material since it is non-reactive with sodium, is inexpensive, has high density (i.e. inertia), and can be obtained in various particle sizes and porosities. Force balance modeling has been used to design a surrogate ambient temperature system that is hydrodynamically similar to the real system, thus allowing complementary investigation of the governing fluidization hydrodynamics. The primary objective of this research was to understand the origin of and to quantify the liquid capillary interparticle forces affecting the molten carbonate SLPC fluidized bed process. Substantial theoretical and experimental exploratory results indicate process

  13. Hydrogenation of toluene on Ni-Co-Mo supported zeolite catalysts ...

    African Journals Online (AJOL)

    -a, HY-b and Mordenite were prepared and characterized using many techniques for use as hydrotreating catalysts. In a preliminary investigation, toluene was employed as model compound to test the catalysts in hydrogenation, as a major ...

  14. Support effects on adsorption and catalytic activation of O2in single atom iron catalysts with graphene-based substrates.

    Science.gov (United States)

    Gao, Zheng-Yang; Yang, Wei-Jie; Ding, Xun-Lei; Lv, Gang; Yan, Wei-Ping

    2018-02-27

    The adsorption and catalytic activation of O 2 on single atom iron catalysts with graphene-based substrates were investigated systematically by density functional theory calculation. It is found that the support effects of graphene-based substrates have a significant influence on the stability of the single atom catalysts, the adsorption configuration, the electron transfer mechanism, the adsorption energy and the energy barrier. The differences in the stable adsorption configuration of O 2 on single atom iron catalysts with different graphene-based substrates can be well understood by the symmetrical matching principle based on frontier molecular orbital analysis. There are two different mechanisms of electron transfer, in which the Fe atom acts as the electron donor in single vacancy graphene-based substrates while the Fe atom mainly acts as the bridge for electron transfer in double vacancy graphene-based substrates. The Fermi softness and work function are good descriptors of the adsorption energy and they can well reveal the relationship between electronic structure and adsorption energy. This single atom iron catalyst with single vacancy graphene modified by three nitrogen atoms is a promising non-noble metal single atom catalyst in the adsorption and catalytic oxidation of O 2 . Furthermore, the findings can lay the foundation for the further study of graphene-based support effects and provide a guideline for the development and design of new non-noble-metal single atom catalysts.

  15. Dehydrogenation of ethylbenzene to styrene using Pt, Mo, and Pt-Mo catalysts supported on clay nanocomposites.

    Science.gov (United States)

    Morán, Cesar; González, Eduardo; Sánchez, Jorge; Solano, Roger; Carruyo, Gabriela; Moronta, Alexander

    2007-11-01

    A synthetic clay (TS-1) was modified with a nonionic surfactant (IGEPAL CO-720) and magnesium oxide. The resulting solid was used as a support of Pt, Mo, and Pt-Mo catalysts. The catalysts were prepared by wet impregnation with aqueous solutions of H(2)PtCl(6)6H(2)O and (NH(4))(6)-Mo(7)O(24)4H(2)O. In both monometallic and bimetallic catalysts, the molybdenum content was 3 wt% and the platinum content was 0.5 or 1 wt%. The surface area of the starting material was 454 m(2)/g and after the modification treatment with IGEPAL it increased up to 649 m(2)/g, while platinum and molybdenum catalysts showed surface areas between 495 and 550 m(2)/g. The reduction profiles showed different Pt and Mo species and the existence of metal-support interactions. The reduced catalysts were more active than those in the unreduced form. The most active catalysts for the ethylbenzene dehydrogenation were those of monometallic Pt (0.5 and 1 wt%) with a maximum styrene conversion around 50%. The presence of Mo species masked Pt atoms and reduced the activity.

  16. Solvent-Free Esterification of Carboxylic Acids Using Supported Iron Oxide Nanoparticles as an Efficient and Recoverable Catalyst

    Directory of Open Access Journals (Sweden)

    Fatemeh Rajabi

    2016-07-01

    Full Text Available Supported iron oxide nanoparticles on mesoporous materials (FeNP@SBA-15 have been successfully utilized in the esterification of a variety carboxylic acids including aromatic, aliphatic, and long-chain carboxylic acids under convenient reaction conditions. The supported catalyst could be easily recovered after reaction completion and reused several times without any loss in activity after up to 10 runs.

  17. Synthesis of 3D structured graphene as a high performance catalyst support for methanol electro-oxidation.

    Science.gov (United States)

    Li, Yecheng; Zhang, Lei; Hu, Zhuofeng; Yu, Jimmy C

    2015-07-07

    A simple process for preparing 3D structured graphene (3D-G) by a solution combustion method is reported. The product was deposited with platinum and used for methanol electro-oxidation. The catalyst shows a considerable enhancement in both the activity and stability towards methanol electro-oxidation reaction. Characterization reveals that the Pt/3D-G catalyst has a more negative onset potential as well as a higher electrochemically active specific surface area than a commercial Pt/C catalyst. Moreover, the catalyst exhibits higher tolerance to corrosion than carbon black. This work provides an efficient way for preparing 3D-G as a promising support for the oxidation of small organic molecules in fuel cells.

  18. PROMOTING EFFECT OF Mo ON Pd / y-Al2O3 SUPPORTED CATALYSTS IN THE OXIDATIVE dehydrogenation OF PROPANE

    Directory of Open Access Journals (Sweden)

    HUGO ZEA

    2011-01-01

    Full Text Available Bimetallic catalysts of Pd-Mo supported on g-Al2O3 were prepared to study the interaction of Pd-Mo in terms of their structural properties and their catalytic activity for the reaction of oxidative dehydrogenation of propane (ODHP. The catalysts contain distributions of Pd- Mo loads between 0 and 5 wt %, and were characterized by total surface area (TSA, total pore volume (TPV, active surface area (ASA, XRD, and TEM-EDS. The results indicate that the addition of Mo to catalysts of Pd/g-Al2O3 modifies its catalytic activity for the ODHP reaction. The influence of the load relationship Pd-Mo in the catalytic activity was determined. Monometallic catalysts were prepared for purposes of comparison.

  19. Nano scale magnetically recoverable supported heteropoly acid as an efficient catalyst for the synthesis of benzimidazole derivatives in water.

    Science.gov (United States)

    Rafiee, Ezzat; Rahpeima, Nasibeh; Eavani, Sara

    2014-01-01

    12-Tungstophosphoric acid supported on silica-coated magnetic nano particles was prepared and characterized by transmission electron microscopy, scanning electron microscopy, powder X-ray diffraction and inductively coupled plasma atomic emission spectroscopy. Acidity of the catalysts was measured by potentiometric titration with n-butylamine. Catalytic activity of the prepared sample was evaluated in the model synthesis of 1,2-disubstituted benzimidazole derivatives in water. The catalyst showed excellent catalytic activity and the corresponding products were obtained in good to excellent yields under mild reaction conditions. Furthermore, the catalyst could be easily recovered using an external magnet and reused several times. The leaching and surface acidity of the recovered catalyst were also investigated.

  20. Non-destructive electrochemical graphene transfer from reusable thin-film catalysts

    DEFF Research Database (Denmark)

    Pizzocchero, Filippo; Jessen, Bjarke Sørensen; Whelan, Patrick Rebsdorf

    2015-01-01

    We demonstrate an electrochemical method - which we term oxidative decoupling transfer (ODT) - for transferring chemical vapor deposited graphene from physically deposited copper catalyst layers. This copper oxidation-based transfer technique is generally applicable to copper surfaces......, and is particularly suitable where the copper is adhered to a substrate such as oxidized silicon. Graphene devices produced via this technique demonstrate 30% higher mobility than similar devices produced by standard catalyst etching techniques. The transferred graphene films cover more than 94% of target substrates...... the threshold for hydrogen production by electrolysis of water - we avoid the formation of hydrogen bubbles at the graphene-copper interface, preventing delamination of thin sputtered catalyst layers from their supporting substrates. We demonstrate the reuse of the same growth substrate for five growth...

  1. Controlled Synthesis of Carbon-Encapsulated Copper Nanostructures by Using Smectite Clays as Nanotemplates

    NARCIS (Netherlands)

    Tsoufis, Theodoros; Colomer, Jean-Francois; Maccallini, Enrico; Jankovic, Lubos; Rudolf, Petra; Gournis, Dimitrios; Jankovič, Lubos

    Rhomboidal and spherical metallic-copper nanostructures were encapsulated within well-formed graphitic shells by using a simple chemical method that involved the catalytic decomposition of acetylene over a copper catalyst that was supported on different smectite clays surfaces by ion-exchange. These

  2. Oxidation of CO and Methanol on Pd-Ni Catalysts Supported on Different Chemically-Treated Carbon Nanofibers

    Directory of Open Access Journals (Sweden)

    Juan Carlos Calderón

    2016-10-01

    Full Text Available In this work, palladium-nickel nanoparticles supported on carbon nanofibers were synthesized, with metal contents close to 25 wt % and Pd:Ni atomic ratios near to 1:2. These catalysts were previously studied in order to determine their activity toward the oxygen reduction reaction. Before the deposition of metals, the carbon nanofibers were chemically treated in order to generate oxygen and nitrogen groups on their surface. Transmission electron microscopy analysis (TEM images revealed particle diameters between 3 and 4 nm, overcoming the sizes observed for the nanoparticles supported on carbon black (catalyst Pd-Ni CB 1:2. From the CO oxidation at different temperatures, the activation energy Eact for this reaction was determined. These values indicated a high tolerance of the catalysts toward the CO poisoning, especially in the case of the catalysts supported on the non-chemically treated carbon nanofibers. On the other hand, apparent activation energy Eap for the methanol oxidation was also determined finding—as a rate determining step—the COads diffusion to the OHads for the catalysts supported on carbon nanofibers. The results here presented showed that the surface functional groups only play a role in the obtaining of lower particle sizes, which is an important factor in the obtaining of low CO oxidation activation energies.

  3. Effect of niobium addition in support catalysts applied in satellite propulsion

    Energy Technology Data Exchange (ETDEWEB)

    Soares, M.S., E-mail: marciosteinmetz@hotmail.com.br [Space Research National Institute, Combustion & Propulsion Associated Laboratory (Brazil); University of São Paulo, Lorena Engineering School, Materials Engineering Dept. (Brazil); Barbosa, R.D. [Space Research National Institute, Combustion & Propulsion Associated Laboratory (Brazil); University of São Paulo, Lorena Engineering School, Chemical Engineering Dept. (Brazil); Cruz, G.M. da; Rodrigues, J.A.J. [Space Research National Institute, Combustion & Propulsion Associated Laboratory (Brazil); Ribeiro, S. [University of São Paulo, Lorena Engineering School, Materials Engineering Dept. (Brazil)

    2017-03-01

    Catalysts composed of iridium as the active phase dispersed in aluminum oxide (Ir/Al{sub 2}O{sub 3}) are used in propulsion systems that employ hydrazine as monopropellant in the control of satellite orbit and attitude. The aluminum oxide (Al{sub 2}O{sub 3}) utilized as support must present high values of specific surface area, pore volume, and crush strength. The niobium effect was evaluated in this work, in its oxide form (Nb{sub 2}O{sub 5}), by 3 different methods: with the employment of a NbCl{sub 5} precursor solution, by wet impregnation and dry impregnation of an alumina obtained from a mixture of gibbsite and boehmite and by physical mixing of gibbsite and hydrated niobium oxide, both autoclaved separately. Aluminum oxides were prepared in both cases containing Nb{sub 2}O{sub 5} contents of 10, 20, and 30% w/w. The acid impregnating NbCl{sub 5} solution in the wet impregnation method caused a strong attack to the Al{sub 2}O{sub 3} support, altering and compromising its initial structure and morphology. This process did not occur in the supports prepared by dry impregnation. However, results indicated that the use of this methodology with Nb{sub 2}O{sub 5} contents of 20% and 30%, caused an extensive coverage of the support by Nb{sub 2}O{sub 5}, modifying the nature and amount of alumina sites responsible for anchorage of the iridium precursor. In the case of supports prepared through physical mixture (Nb{sub 2}O{sub 5}-Al{sub 2}O{sub 3}) from aluminum hydroxide and niobium acid precursor compounds, with both being previously autoclaved separately, the 20% and 30% Nb{sub 2}O{sub 5} contents presented the most promising properties, since the binder effect caused by amorphous Nb{sub 2}O{sub 5} increased the crush strength of the support, without compromising the aluminum oxide morphology and texture. Despite of existence of stronger acid sites due to the addition of niobium oxide to aluminum oxide, no increase in the acidity of the materials was observed due

  4. Influence of reaction parameters on the hydrogenolysis of hydroxymatairesinol over carbon nanofibre supported palladium catalysts

    NARCIS (Netherlands)

    Bernas, H.; Plomp, A.J.|info:eu-repo/dai/nl/304837598; Bitter, J.H.|info:eu-repo/dai/nl/160581435; Murzin, D.Y.

    2008-01-01

    The influence of catalyst particle size, stirring rate, catalyst mass (0.2–0.6 g), reaction temperature (60–70 C), and reactant concentration (1.3–4 mmol/L, with constant reactant/catalyst ratio) on the hydrogenolysis of the lignan hydroxymatairesinol (HMR) to matairesinol (MAT) was studied under

  5. Hydrogenation of Anthracene in Supercritical Carbon Dioxide Solvent Using Ni Supported on Hβ-Zeolite Catalyst

    Directory of Open Access Journals (Sweden)

    Ashraf Aly Hassan

    2012-01-01

    Full Text Available Catalytic hydrogenation of anthracene was studied over Ni supported on Hβ-zeolite catalyst under supercritical carbon dioxide (sc-CO2 solvent. Hydrogenation of anthracene in sc-CO2 yielded 100% conversion at 100 °C, which is attributed to the reduced mass transfer limitations, and increased solubility of H2 and substrate in the reaction medium. The total pressure of 7 MPa was found to be optimum for high selectivity of octahydroanthracene (OHA. The conversion and selectivity for OHA increased with an increase in H2 partial pressure, which is attributed to higher concentration of hydrogen atoms at higher H2 pressures. The selectivity reduced the pressure below 7 MPa because of enhanced desorption of the tetrahydro-molecules and intermediates from Ni active sites, due to higher solubility of the surface species in sc-CO2. The selectivity of OHA increased with the increase in catalyst weight and reaction time. The rate of hydrogenation of anthracene was compared with that found for napthalene and phenanthrene. The use of acetonitrile as co-solvent or expanded liquid with CO2 decreased the catalytic activity.

  6. Mass-produced multi-walled carbon nanotubes as catalyst supports for direct methanol fuel cells.

    Science.gov (United States)

    Jang, In Young; Park, Ki Chul; Jung, Yong Chae; Lee, Sun Hyung; Song, Sung Moo; Muramatsu, Hiroyuki; Kim, Yong Jung; Endo, Morinobu

    2011-01-01

    Commercially mass-produced multi-walled carbon nanotubes, i.e., VGNF (Showa Denko Co.), were applied to support materials for platinum-ruthenium (PtRu) nanoparticles as anode catalysts for direct methanol fuel cells. The original VGNFs are composed of high-crystalline graphitic shells, which hinder the favorable surface deposition of the PtRu nanoparticles that are formed via borohydride reduction. The chemical treatment of VGNFs with potassium hydroxide (KOH), however, enables highly dispersed and dense deposition of PtRu nanoparticles on the VGNF surface. This capability becomes more remarkable depending on the KOH amount. The electrochemical evaluation of the PtRu-deposited VGNF catalysts showed enhanced active surface areas and methanol oxidation, due to the high dispersion and dense deposition of the PtRu nanoparticles. The improvement of the surface deposition states of the PtRu nanoparticles was significantly due to the high surface area and mesorporous surface structure of the KOH-activated VGNFs.

  7. On oxygen chemisorption for characterization of silica-supported vanadium oxide catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Faraldos, M.; Banares, M.A.; Fierro, J.L.G. [Instituto de Catalysis y Petroleoquimica, Madrid (Spain)] [and others

    1997-05-01

    Oxygen chemisorption experiments on prereduced silica- supported vanadia catalysts have been performed in order to determine the optimum conditions for measuring the relative dispersion of vanadium oxide on the silica substrate. By following the extent of vanadia reduction microgravimetrically, it is shown that an appropriate prereduction of the catalyst at 823 K under hydrogen is fundamental in obtaining a reproducible well-defined stoichiometrically reduced vanadium oxide system (V{sup 3+}). AT 643 K the reduction process is very much slower and requires very long times in order to approach a plateau. Measurement of the binding energies of the V{sub 2}p{sub 3/2} core level spectra indicates that high-temperature oxygen chemisorption (643 K) results in a reoxidation of the prereduced vanadium oxide species within crystallites leading to an overestimation of the number of exposed vanadium sites. Chemisorption at low temperatures (298 or 195 K) does not affect the stoichiometrically reduced vanadium oxide species within crystallites, thus allowing the number of exposed surface vanadium sites to be measured. 25 refs., 5 figs., 1 tab.

  8. Light alkane (mixed feed selective dehydrogenation using bi-metallic zeolite supported catalyst

    Directory of Open Access Journals (Sweden)

    Zeeshan Nawaz

    2009-12-01

    Full Text Available Light alkanes are the important intermediates of many refinery processes and their catalytic dehydrogenation gives corresponding alkenes. The aim behind this experimentation is to investigate reaction behavior of mixed alkanes during direct catalytic dehydrogenation and emphasis has been given to enhance propene. Bi-metallic zeolite supported catalyst Pt-Sn/ZSM-5 was prepared by sequentional impregnation method and characterized by BET, EDS and XRD. Direct dehydrogenation reaction is highly endothermic and its conversion is thermodynamically limited. Results showed that the increase in temperature increases the conversion to some extent but there is no overall effect on selectivity of propene. Increase in time-on-stream (TOS remarkably improves propene selectivity at the expense of lower conversion. The performances of bi-metallic zeolite based catalyst largely affected by coke deposition. The presence of butane and ethane adversely affected propane conversion. Optimum propene selectivity is about 48 %, obtained at 600 oC and time-on-stream 10 h.

  9. COPPER OCTOATE: A COMMERCIALLY AVAILABLE AND COST-EFFECTIVE HOMOGENEOUS CATALYST FOR THE FACILE SYNTHESIS OF 2,2’-ARYLMETHYLENEBIS(3-HYDROXY-5,5-DIMETHYL-2-CYCLOHEXENE-1-ONES

    Directory of Open Access Journals (Sweden)

    Rahim Hekmatshoar

    2015-02-01

    Full Text Available A practical and convenient approach for the synthesis of 2,2’-arylmethylenebis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-ones was presented using copper octoate as a homogeneous catalyst. Copper octoate as an eco-friendly, low cost, and commercially available catalyst, reduced reaction times effectively to (16-50 min while the reaction profiles were absolutely clean and no side products including dehydrated xanthene heterocycle were detected. Pure target compounds were obtained in very good to excellent yields (83-91% via straightforward work-up procedure. The catalyst was recycled in the form of solution, up to four times, with no noticeable drop in activity.

  10. Supported nano gold as a recyclable catalyst for green, selective and efficient oxidation of alcohol using molecular oxygen

    Directory of Open Access Journals (Sweden)

    Bashir Dar

    2011-09-01

    Full Text Available The myth that gold cannot act as a catalyst has been discarded in view of recent studies, which have demonstrated the high catalytic efficiency of pure nano-gold and supported nano-gold catalysts. In recent years, numerous papers have described the use of supported nano-gold particles for catalysis in view of their action on CO and O2 to form CO2, as well as a variety of other reactions. Special emphasis is placed on the oxidation studies undertaken on model nano-Au systems. In this work a solvent free oxidation of 1-phenyl ethanol was carried out using gold supported on ceria-silica, ceria-titania, ceria- zirconia and ceria-alumina at 160 0C. Almost 88-97% conversion was obtained with >99% selectivity. Temperature screening was done from 70 to 160 0C.Catalysts were prepared by deposition co-precipitation method and deposition was determined by EDEX analysis.

  11. Mechanism and kinetics of Fischer-Tropsch synthesis over supported ruthenium catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Kellner, C.S.

    1981-06-01

    A detailed study of the kinetics of the Fischer-Tropsch synthesis of hydrocarbons, methanol, and acetaldehyde, over alumina- and silica-supported ruthenium catalysts has been carried out over a broad range of reaction conditions. Based on these results and information taken from the literature, mechanisms for the formation of normal paraffins, ..cap alpha..-olefins, methanol, and acetaldehyde have been proposed. Rate data were obtained between 448 and 548K, 1 and 10 atm, and H/sub 2//CO ratios between 1 and 3, utilizing a micro flow reactor operated at very low conversions. In addition to the studies performed with H/sub 2//CO mixtures, a series of experiments were carried out utilizing D/sub 2//CO mixtures. These studies were used to help identify rate limited steps and steps that were at equilibrium. A complementary investigation, carried out by in situ infrared spectroscopy, was performed using a Fourier Transform spectrometer. The spectra obtained were used to identify the modes of CO adsorption, the CO coverage, and the relative reactivity of different forms of adsorbed CO. It was established that CO adsorbs on alumina-supported Ru in, at least, two forms: (i) Ru-CO and (ii) OC-Ru-CO. Only the first of these forms participates in CO hydrogenation. The coverage of this species is described by a simple Langmuir isotherm. A reaction mechanism is presented for interpreting the kinetics of hydrocarbon synthesis, the olefin to paraffin ratio for each product, and the probability of chain propagation. Rate expressions based on this mechanism are reasonably consistent with the experimental data. Acetaldehyde, obtained mainly over silica-supported Ru, appears to be formed by a mechanism related to that for hydroformulation of olefins. The effect of the dispersion of Ru/Al/sub 2/O/sub 3/ catalysts on their specific activity and selectivity was also investigated. The specific activity for all products decreased rapidly with increasing dispersions.

  12. Influence of various carbon nano-forms as supports for Pt catalyst on proton exchange membrane fuel cell performance

    Science.gov (United States)

    Bharti, Abha; Cheruvally, Gouri

    2017-08-01

    In this study, we discuss the influence of various carbon supports for Pt on proton exchange membrane (PEM) fuel cell performance. Here, Pt supported on various carbon nano-forms [Pt/carbon black (Pt/CB), Pt/single-walled carbon nanotubes (Pt/SWCNT), Pt/multi-walled carbon nanotubes (Pt/MWCNT) and Pt/graphene (Pt/G)] are synthesized by a facile, single step, microwave-assisted, modified chemical reduction route. Their physical, chemical and electrochemical characteristics pertaining to oxygen reduction reaction (ORR) catalytic activity and stability in PEM fuel cell are studied in detail by various techniques and compared. The study shows that the different carbon supports does not significantly affect the Pt particle size during synthesis, but leads to different amount of defective sites in the carbon framework which influence both the availability of active metal nano-catalysts and metal-support interaction. In-situ electrochemical investigations reveal that the different carbon supports influence both ORR catalytic activity and stability of the catalyst. This is further corroborated by the demonstration of varying polarization characteristics on PEM fuel cell performance by different carbon supported Pt catalysts. This study reveals MWCNT as the most suitable carbon support for Pt catalyst, exhibiting high activity and stability for ORR in PEM fuel cell.

  13. Combustion synthesized copper-ion substituted FeAl2O4 (Cu0.1Fe0.9Al2O4): A superior catalyst for methanol steam reforming compared to its impregnated analogue

    Science.gov (United States)

    Maiti, Sayantani; Llorca, Jordi; Dominguez, Montserrat; Colussi, Sara; Trovarelli, Alessandro; Priolkar, Kaustubh R.; Aquilanti, Giuliana; Gayen, Arup

    2016-02-01

    A series of copper ion substituted MAl2O4 (M = Mg, Mn, Fe and Zn) spinels is prepared by a single step solution combustion synthesis (SCS) and tested for methanol steam reforming (MSR). The copper ion substituted Cu0.1Fe0.9Al2O4 appears to be the most active, showing ∼98% methanol conversion at 300 °C with ∼5% CO selectivity at GHSV = 30,000 h-1 and H2O:CH3OH = 1.1. The analogous impregnated catalyst, CuO (10 at%)/FeAl2O4, is found to be much less active. These materials are characterized by XRD, H2-TPR, BET, HRTEM, XPS and XANES analyses. Spinel phase formation is highly facilitated upon Cu-ion substitution and Cu loading beyond 10 at% leads to the formation of CuO as an additional phase. The ionic substitution of copper in FeAl2O4 leads to the highly crystalline SCS catalyst containing Cu2+ ion sites that are shown to be more active than the dispersed CuO nano-crystallites on the FeAl2O4 impregnated catalyst, despite its lower surface area. The as prepared SCS catalyst contains also a portion of copper as Cu1+ that increases when subjected to reforming atmosphere. The MSR activity of the SCS catalyst decreases with time-on-stream due to the sintering of catalyst crystallites as established from XPS and HRTEM analyses.

  14. Catalytic Chemical Vapor Deposition of Methane to Carbon Nanotubes: Copper Promoted Effect of Ni/MgO Catalysts

    Directory of Open Access Journals (Sweden)

    Wen Yang

    2014-01-01

    Full Text Available The Ni/MgO and Ni-Cu/MgO catalysts were prepared by sol-gel method and used as the catalysts for synthesis of carbon nanotubes by thermal chemical vapor deposition. The effect of Cu on the carbon yield and structure was investigated, and the effects of calcination temperature and reaction temperature were also investigated. The catalysts and synthesized carbon materials were characterized by temperature programmed reduction (TPR, thermogravimetric analysis (TGA, and scanning electron microscopy (SEM. Results showed that the addition of Cu promoted the reduction of nickel species, subsequently improving the growth and yield of CNTs. Meanwhile, CNTs were synthesized by the Ni/MgO and Ni-Cu/MgO catalysts with various calcination temperatures and reaction temperatures, and results suggested that the obtained CNTs on Ni-Cu/MgO catalyst with the calcination temperature of 500°C and the reaction temperature of 650°C were of the greatest yield and quantity of 927%.

  15. Single-step immobilization of cell adhesive peptides on a variety of biomaterial substrates via tyrosine oxidation with copper catalyst and hydrogen peroxide.

    Science.gov (United States)

    Kakinoki, Sachiro; Yamaoka, Tetsuji

    2015-04-15

    Immobilization of biologically active peptides which were isolated from extracellular matrix proteins is a powerful strategy for the design and functionalization of biomaterial substrates. However, the method of peptide immobilization was restricted, that is, peptide is often immobilized through the reactive groups inherent in substrates with multistep reactions. Here, we report a single-step immobilization of fibronectin-derived cell adhesive peptide (Arg-Glu-Asp-Val; REDV) onto polymer materials by use of tyrosine oxidation with copper catalyst and hydrogen peroxide. REDV peptide was successfully immobilized on tissue culture polystyrene, poly(ethylene terephthalate), poly(vinyl chloride), expanded-poly(tetrafluoroethylene), and poly(l-lactic acid), resulting in enhanced adhesion of human umbilical vein endothelial cells. This method is a single-step reaction under very mild conditions and is available for the biological functionalization of various medical devices.

  16. Selective nano alumina supported vanadium oxide catalysts for oxidative dehydrogenation of ethylbenzene to styrene using CO2 as soft oxidant

    Directory of Open Access Journals (Sweden)

    A.M. Elfadly

    2013-12-01

    Full Text Available Nano alumina-supported V2O5 catalysts with different loadings have been tested for the dehydrogenation of ethylbenzene with CO2 as an oxidant. High surface area nano-alumina was prepared and used as support for V2O5 as the catalyst. The catalysts were synthesized by impregnation techniques followed by calcinations and microwave treatment, denoted as V2O5/γ-Al2O3-C and V2O5/γ-Al2O3-MW, respectively. The V2O5 loading was varied on nano-alumina from 5 to 30 wt%. The support and catalysts were characterized by X-ray diffraction (XRD, Barett–Joyner–Halenda (BJH pore-size distribution, N2-adsorption isotherms, Fourier transform infrared (FT-IR, scanning electron microscopy (SEM, transmission electron microscopy (TEM and temperature programed desorption (TPD-NH3. The characterization results indicated that V2O5 is highly dispersed on alumina up to 30%-V2O5/γ-Al2O3-MW prepared by MW method. The TPD studies indicated that there are significant differences in acid amount and strength for V2O5/γ-Al2O3-C and V2O5/γ-Al2O3-MW-catalysts. The catalytic activity of the prepared catalysts was evaluated in the temperature range 450–600 °C in relation to the physicochemical properties and surface acidity. The results revealed that optimum catalytic activity and selectivity (∼100% toward styrene production were obtained using 10% V2O5/γ-Al2O3-MW catalyst treated with microwave.

  17. Silica-supported sulfonic acids as recyclable catalyst for esterification of levulinic acid with stoichiometric amounts of alcohols

    Directory of Open Access Journals (Sweden)

    Raimondo Maggi

    2016-10-01

    Full Text Available Converting biomass into value-added chemicals holds the key to sustainable long-term carbon resource management. In this context, levulinic acid, which is easily obtained from cellulose, is valuable since it can be transformed into a variety of industrially relevant fine chemicals. Here we present a simple protocol for the selective esterification of levulinic acid using solid acid catalysts. Silica supported sulfonic acid catalysts operate under mild conditions and give good conversion and selectivity with stoichiometric amounts of alcohols. The sulfonic acid groups are tethered to the support using organic tethers. These tethers may help in preventing the deactivation of the active sites in the presence of water.

  18. Crumpled rGO-supported Pt-Ir bifunctional catalyst prepared by spray pyrolysis for unitized regenerative fuel cells

    Science.gov (United States)

    Kim, In Gyeom; Nah, In Wook; Oh, In-Hwan; Park, Sehkyu

    2017-10-01

    Three-dimensional (3D) crumpled reduced graphene oxide supported Pt-Ir alloys that served as bifunctional oxygen catalysts for use in untized regenerative fuel cells were synthesized by a facile spray pyrolysis method. Pt-Ir catalysts supported on rGO (Pt-Ir/rGOs) were physically characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and thermogravimetric analysis (TGA) to observe change in composition by heat treatment, alloying, and morphological transition of the catalysts. Their catalytic activities and stabilities for the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) conditions were electrochemically investigated using cyclic voltammetry (CV), linear sweep voltammetry (LSV), potential cycling and hold tests on the rotating disk electrode (RDE). Pt-Ir/rGO with no post heat-treatment (Pt-Ir/rGO_NP) showed a lower activity for ORR and OER although metal nanoparticles decorated on the support are relatively small. However, Pt-Ir/rGO showed remarkably enhanced activity following heat treatment, depending on temperature. Pt-Ir/rGO heat-treated at 600 °C after spray pyrolysis (Pt-Ir/rGO_P600) exhibited a higher activity and stability than a commercially available Pt/C catalyst kept under the ORR condition, and it also revealed a comparable OER activity and durability versus the commercial unsupported Ir catalyst.

  19. Stereoselective thymol hydrogenation. I. Kinetics of thymol hydrogenation on charcoal-supported platinum catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Besson, M.; Bullivant, L.; Nicolaus, N.; Gallezot, P. (Institut de Recherches sur la Catalyse-CNRS, Villeurbanne (France))

    1993-03-01

    The kinetics of thymol hydrogenation on a well-characterized supported platinum catalyst have been investigated in cyclohexane at temperatures between 313 and 373 K and under 3 MPa of hydrogen pressure. The relative rate constants of the different reaction pathways (hydrogenation via menthone or isomenthone, and direct hydrogenation to the four menthol diastereoisomers) were determined from the changes in composition of the reaction medium during the reaction process. It has been shown that hydrogenation via the menthone intermediates is the major route, the formation of the cis isomer (isomenthone) being favored. The configuration of the menthols, produced from direct hydrogenation or from the ketone intermediates, is controlled by the geometry of adsorption of the precursors on the metal surface, so that neoisomenthol with all substituents in the cis position is by far the most abundant steroisomer produced. 21 refs., 11 figs., 2 tabs.

  20. Heterogenization of Ketone Catalyst for Epoxidation by Low Pressure Plasma Fluorination of Silica Gel Supports.

    Science.gov (United States)

    D'Accolti, Lucia; De Vietro, Nicoletta; Fanelli, Fiorenza; Fusco, Caterina; Nacci, Angelo; Fracassi, Francesco

    2017-11-30

    Low pressure plasma was used for preparing heterogeneous organocatalysts 2 -( A )-( C ) suitable for dioxirane-mediated epoxidations. Heterogenization was accomplished by adsorption of the methyl perfluoroheptyl ketone ( 2 ) on fluorinated supports ( A )-( C ) deriving from the treatment of commercial C₈-silica gel in low pressure plasma fed with fluorocarbons. Catalyst 2 -( C ) proved to be the most efficient one, promoting epoxidation of an array of alkenes, including unsaturated fatty esters like methyl oleate ( 10 ) and the triglyceride soybean oil ( 11 ), with the cheap potassium peroxymonosulfate KHSO₅ (caroate) as a green oxidant. Notably, the perfluorinated matrix gives rise to the activation of caroate, generating singlet oxygen. Materials were characterized by infrared Attenuated Total Reflectance spectroscopy (ATR-FTIR), X-ray Photoelectron Spectroscopy (XPS ) and Emission Scanning Electron Microscope (FESEM).