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Sample records for catalyst supports

  1. Supported organoiridium catalysts for alkane dehydrogenation

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-09-03

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

  2. Alumina supported iridium catalysts - preparation

    International Nuclear Information System (INIS)

    This report describes the method employed in the preparation of alumina supported iridium catalysts, with metal contents between 30 and 40%, that will be used for hydrazine monopropellant decomposition. (author)

  3. Synchrotron radiation studies of supported metal catalysts

    International Nuclear Information System (INIS)

    Metallic clusters supported on refractory oxides have been used extensively for several decades in the production of chemicals and petroleum derived transportation fuels. Catalysts containing more than one metal component are of particular interest since the addition of a second metal provides a method of controlling the selectivity of the catalyst. That is, the second metal can alter the rates of competing reactions in a complex reaction sequence and thus alter the final product distribution of the reaction. In this work the reactions of cyclohexane in hydrogen over silica supported ruthenium and osmium catalysts were studied. Bimetallic catalysts represent an important class of materials that are of interest both scientifically and technologically. Despite the importance and long-standing use of supported metal catalysts, detailed information on the structure of the metal clusters has been difficult to obtain. The development of x-ray absorption spectroscopy with the increasing availability of synchrotron radiation, however, has provided a powerful and versatile tool for studying the structure of these complex systems. Using the Extended X-ray Absorption Fine Structure (EXAFS) technique, it is possible to obtain information on the local atomic structure of supported monometallic catalytic metals and their interaction with the support. In the discussion that follows the authors will focus on results that have been obtained on the structure of supported bimetallic cluster catalysts

  4. 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.

  5. Thermodynamic Properties of Supported Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Gorte, Raymond J.

    2014-03-26

    The goals of this work were to develop Coulometric Titration as a method for characterizing the thermodynamic redox properties of oxides and to apply this technique to the characterization of ceria- and vanadia-based catalysts. The redox properties of ceria and vanadia are a major part of what makes these materials catalytically active but their properties are also dependent on their structure and the presence of other oxides. Quantifying these properties through the measurement of oxidation energetics was the goal of this work.

  6. Overview of Support Effects in Hydrotreating Catalysts

    Institute of Scientific and Technical Information of China (English)

    Michèle Breysse

    2004-01-01

    @@ Industrial hydrotreating (HDT) catalysts are composed of a molybdenum sulfide (or tungsten sulfide) phase promoted by cobalt or nickel and usually supported on alumina. The origin of the almost exclu1sive use of alumina as support has to be ascribed to its outstanding textural and mechanical properties and its relatively low cost[1].

  7. Thermal decomposition of supported lithium nitrate catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz, Maria Lucia [INTEQUI (CONICET-UNSL), 25 de Mayo 384, V. Mercedes, 5730, San Luis (Argentina); Lick, Ileana Daniela [CINDECA (CONICET-UNLP), Calle 47 No 257, La Plata, 1900, Buenos Aires (Argentina); Ponzi, Marta Isabel [INTEQUI (CONICET-UNSL), 25 de Mayo 384, V. Mercedes, 5730, San Luis (Argentina); Castellon, Enrique Rodriguez; Jimenez-Lopez, Antonio [Departamento de Quimica Inorganica, Cristalografia y Mineralogia. Facultad de Ciencias, Universidad de Malaga, Campus de Teatinos, 29071 Malaga (Spain); Ponzi, Esther Natalia, E-mail: eponzi@quimica.unlp.edu.ar [CINDECA (CONICET-UNLP), Calle 47 No 257, La Plata, 1900, Buenos Aires (Argentina)

    2010-02-20

    New catalysts for soot combustion were prepared by impregnation of different supports (SiO{sub 2}, ZrO{sub 2} and ZrO{sub 2}.nH{sub 2}O) with a LiNO{sub 3} solution and then characterized by means of FTIR, XPS, TGA and UV-vis spectroscopy, whereby the presence of lithium nitrate in the prepared catalysts was identified and quantified. The soot combustion rate using this series of catalysts (LiNO{sub 3}/support) was compared with the activity of a series of impregnated catalysts prepared using LiOH (Li{sub 2}O/supports). Catalysts prepared using LiNO{sub 3} are found to be more active than those prepared using LiOH. The catalytic performance was also studied with a NO/O{sub 2} mixture in the feed, demonstrating that NO increases the combustion rate of soot, probably as a consequence of lithium oxide forming an 'in situ' nitrate ion.

  8. 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.

  9. Polypropylene obtained through zeolite supported catalysts

    International Nuclear Information System (INIS)

    Propylene polymerizations were carried out with φ2C(Flu)(Cp)ZrCl2 and SiMe2(Ind)2ZrCl2 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)(Cp)ZrCl2, 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 stereo regularity. (author)

  10. Alkane dehydrogenation over supported chromium oxide catalysts

    NARCIS (Netherlands)

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

    1999-01-01

    The dehydrogenation of alkanes over supported chromium oxide catalysts in the absence of oxygen is of high interest for the industrial production of propene and isobutene. In this review, a critical overview is given of the current knowledge nowadays available about chromium-based dehydrogenation ca

  11. Carbon Fiber Composite Monoliths as Catalyst Supports

    Energy Technology Data Exchange (ETDEWEB)

    Contescu, Cristian I [ORNL; Gallego, Nidia C [ORNL; Pickel, Joseph M [ORNL; Blom, Douglas Allen [ORNL; Burchell, Timothy D [ORNL

    2006-01-01

    Carbon fiber composite monoliths are rigid bodies that can be activated to a large surface area, have tunable porosity, and proven performance in gas separation and storage. They are ideal as catalyst supports in applications where a rigid support, with open structure and easy fluid access is desired. We developed a procedure for depositing a dispersed nanoparticulate phase of molybdenum carbide (Mo2C) on carbon composite monoliths in the concentration range of 3 to 15 wt% Mo. The composition and morphology of this phase was characterized using X-ray diffraction and electron microscopy, and a mechanism was suggested for its formation. Molybdenum carbide is known for its catalytic properties that resemble those of platinum group metals, but at a lower cost. The materials obtained are expected to demonstrate catalytic activity in a series of hydrocarbon reactions involving hydrogen transfer. This project demonstrates the potential of carbon fiber composite monoliths as catalyst supports.

  12. Carbon Fiber Composite Monoliths for Catalyst Supports

    Energy Technology Data Exchange (ETDEWEB)

    Contescu, Cristian I [ORNL; Gallego, Nidia C [ORNL; Pickel, Joseph M [ORNL; Blom, Douglas Allen [ORNL; Burchell, Timothy D [ORNL

    2006-01-01

    Carbon fiber composite monoliths are rigid bodies that can be activated to a large surface area, have tunable porosity, and proven performance in gas separation and storage. They are ideal as catalyst supports in applications where a rigid support, with open structure and easy fluid access is desired. We developed a procedure for depositing a dispersed nanoparticulate phase of molybdenum carbide (Mo2C) on carbon composite monoliths in the concentration range of 3 to 15 wt% Mo. The composition and morphology of this phase was characterized using X-ray diffraction and electron microscopy, and a mechanism was suggested for its formation. Molybdenum carbide is known for its catalytic properties that resemble those of platinum group metals, but at a lower cost. The materials obtained are expected to demonstrate catalytic activity in a series of hydrocarbon reactions involving hydrogen transfer. This project demonstrates the potential of carbon fiber composite monoliths as catalyst supports.

  13. Titanium Dioxide as a Catalyst Support in Heterogeneous Catalysis

    OpenAIRE

    Samira Bagheri; Nurhidayatullaili Muhd Julkapli; Sharifah Bee Abd Hamid

    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 nanopa...

  14. 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.

  15. Design strategies for the molecular level synthesis of supported catalysts.

    Science.gov (United States)

    Wegener, Staci L; Marks, Tobin J; Stair, Peter C

    2012-02-21

    Supported catalysts, metal or oxide catalytic centers constructed on an underlying solid phase, are making an increasingly important contribution to heterogeneous catalysis. For example, in industry, supported catalysts are employed in selective oxidation, selective reduction, and polymerization reactions. Supported structures increase the thermal stability, dispersion, and surface area of the catalyst relative to the neat catalytic material. However, structural and mechanistic characterization of these catalysts presents a formidable challenge because traditional preparations typically afford complex mixtures of structures whose individual components cannot be isolated. As a result, the characterization of supported catalysts requires a combination of advanced spectroscopies for their characterization, unlike homogeneous catalysts, which have relatively uniform structures and can often be characterized using standard methods. Moreover, these advanced spectroscopic techniques only provide ensemble averages and therefore do not isolate the catalytic function of individual components within the mixture. New synthetic approaches are required to more controllably tailor supported catalyst structures. In this Account, we review advances in supported catalyst synthesis and characterization developed in our laboratories at Northwestern University. We first present an overview of traditional synthetic methods with a focus on supported vanadium oxide catalysts. We next describe approaches for the design and synthesis of supported polymerization and hydrogenation catalysts, using anchoring techniques which provide molecular catalyst structures with exceptional activity and high percentages of catalytically significant sites. We then highlight similar approaches for preparing supported metal oxide catalysts using atomic layer deposition and organometallic grafting. Throughout this Account, we describe the use of incisive spectroscopic techniques, including high

  16. Monolayer dispersion thresholds and threshold effect displayed by supported catalysts

    Institute of Scientific and Technical Information of China (English)

    Cun DENG

    2008-01-01

    The principle of spontaneous monolayer dis-persion holds that active components of many supported catalysts will disperse spontaneously onto the surface of the carrier. The monolayer dispersion threshold of the active component on the surface of the carrier can be measured by X-ray diffraction phase-quantitative extra-polation method, etc. By measuring the monolayer disper-sion threshold, beneficial information on the surface structure and dispersion of supported catalysts can be obtained, and the optimal preparative processing condi-tions of the catalysts can be chosen. The proportion of the active component of many supported catalysts can be optimized while its monolayer dispersion threshold is observed. Mutation values of many physicochemical properties of supported catalysts are related to monolayer dispersion thresholds; the threshold effect on catalysts is apparent, and the proposal regarding the threshold effect provides instruction for the research on catalysts.

  17. 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

    , we report a more detailed catalytic study aimed at optimizing the catalyst performance. For this purpose, two series of mono and bimetallic Ni-Fe catalysts supported on MgAl2O4 and Al2O3, respectively, were prepared. All catalysts were tested in the CO methanation reaction in the temperature interval...

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

    OpenAIRE

    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 gold nanoparticles was established for all catalyst materials, only a very low activity for the total oxidation of methane was observed, at temperatures[250 C. Since no traces of partial oxidation...

  19. Ceramic wash-coat for catalyst support

    Science.gov (United States)

    Kulkarni, Anand A.; Subramanian, Ramesh; Sabol, Stephen M.

    2012-08-14

    A wash-coat (16) for use as a support for an active catalyst species (18) and a catalytic combustor component (10) incorporating such wash-coat. The wash-coat is a solid solution of alumina or alumina-based material (Al.sub.2O.sub.3-0-3 wt % La.sub.2O.sub.3) and a further oxide exhibiting a coefficient of thermal expansion that is lower than that exhibited by alumina. The further oxide may be silicon dioxide (2-30 wt % SiO.sub.2), zirconia silicate (2-30 wt % ZrSiO.sub.4), neodymium oxide (0-4 wt %), titania (Al.sub.2O.sub.3-3-40% TiO.sub.2) or alumina-based magnesium aluminate spinel (Al.sub.2O.sub.3-25 wt % MgO) in various embodiments. The active catalyst species may be palladium and a second metal in a concentration of 10-50% of the concentration of the palladium.

  20. 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...

  1. 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

  2. Characteristics of Titanocene Catalyst Supported on Palygorskite for Ethylene Polymerization

    Institute of Scientific and Technical Information of China (English)

    Xiao Wei YAN; Jing Dai WANG; Yi Bing SHAN; Yong Rong YANG

    2006-01-01

    A series of heterogeneous catalysts with Cp2TiCl2 supported on palygorskite were prepared and evaluated by ethylene slurry polymerizations. The so-called direct supported catalyst, for which the pretreatment of palygorskite with MAO or Al(i-Bu)3 was not necessary,gave the highest activity among these supported catalysts and could be more robust than homogeneous Cp2TiCl2. With the direct supported catalyst, no significant activity loss was observed under low Al/Ti molar ratios (Al/Ti=300) and the decay of polymerization rate was slower when compared to the other supported catalysts. It was found that the surface Lewis acidity of palygorskite after thermal treatment played an important role in activation of metallocene compound and resulted in high catalyst activity.

  3. Method of forming supported doped palladium containing oxidation catalysts

    Science.gov (United States)

    Mohajeri, Nahid

    2014-04-22

    A method of forming a supported oxidation catalyst includes providing a support comprising a metal oxide or a metal salt, and depositing first palladium compound particles and second precious metal group (PMG) metal particles on the support while in a liquid phase including at least one solvent to form mixed metal comprising particles on the support. The PMG metal is not palladium. The mixed metal particles on the support are separated from the liquid phase to provide the supported oxidation catalyst.

  4. Palladium-supported catalysts in methane combustion: comparison of alumina and zirconia supports

    Directory of Open Access Journals (Sweden)

    Daniela Domingos

    2012-01-01

    Full Text Available Palladium catalysts supported on alumina and zirconia were prepared by the impregnation method and calcined at 600 and 1000 ºC. Catalysts were characterized by BET measurements, XRD, XPS, O2-TPD and tested in methane combustion through temperature programmed surface reaction. Alumina supported catalysts were slightly more active than zirconia supported catalysts, but after initial heat treatment at 1000 ºC, zirconia supported palladium catalyst showed better performance above 500 ºC A pattern between temperature interval stability of PdOx species and activity was observed, where better PdOx stability was associated with more active catalysts.

  5. 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.

  6. Carbon Nanofibers as Catalyst Support for Noble Metals

    OpenAIRE

    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 described in this thesis has been the exploration of the potential of CNF as catalyst support material, notably for platinum and ruthenium, and its role in the performance of these catalysts in hyd...

  7. XPS studies of Pt catalysts supported on porous carbon

    Science.gov (United States)

    Tyagi, Deepak; Varma, Salil; Bharadwaj, S. R.

    2016-05-01

    Pt catalysts supported on porous carbon were prepared by hard templating route and used for HI decomposition reaction of Sulfur Iodine thermochemical cycle. These catalysts were characterized by X-ray photoelectron spectroscopy for oxidation state of platinum as well as nature of carbon present in the catalysts. It was found that platinum is present in metallic state and carbon is present in both sp2 and sp3 hybridization states. The catalysts were evaluated for their activity and stability for liquid phase HI decomposition reaction and it was observed that mesoporous carbon based catalysts were more active and stable under the reaction conditions.

  8. Graphene: A Promising Two-Dimensional Support for Heterogeneous Catalysts

    OpenAIRE

    Fan, Xiaobin

    2015-01-01

    Graphene has many advantages that make it an attractive two-dimensional (2D) support for heterogeneous catalysts. It not only allows the high loading of targeted catalytic species but also facilitates the mass transfer during the reaction processes. These advantages, along with its unique physical and chemical properties, endow graphene great potential as catalyst support in heterogeneous catalysis.

  9. Ethylene Polymerization with Palygorskite Supported Nickel-Diimine Catalyst

    Institute of Scientific and Technical Information of China (English)

    严小伟; 王靖贷; 阳永荣; 张雷

    2005-01-01

    A nickel-diimine catalyst IN, N′-bis(2,6-diisopropylphenyl)-1,4-diaza-2,3-dimethyl-1, 3-butadiene nickel dibromide, DMN] was supported on palygorskite clay for ethylene slurry polymerization. The effect of supporting methods on the catalyst impregnation was studied and compared. Pretreatment of the support with methylaluminoxane (MAO) followed by DMN impregnation gave higher catalyst loading and catalytic activity than the direct impregnation of DMN. Catalyst activity as high as 5.42 × 105 g PE·molNi-l·h-1 was achieved at ethylene pressure of 6.87 × 105 Pa and polymerization temperature of 20℃ In particular, the morphological change of the support during MAO treatment was characterized and analyzed. It was found that nano-fiber clusters formed during the support pretreatment, which increased the surface area of the support and favored the impregnation of the catalyst. The investigation of polymerization behavior of supported catalyst revealed that the polymerization rate could be kept at a relatively high level for a long time, different from the homogeneous catalyst. By analyzing the SEM photographs of the polymer produced by the supported catalyst, the morphological evolution of polymer particles was preliminarily studied.

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

    Science.gov (United States)

    Mansor, Noramalina; Jorge, A Belen; Corà, Furio; Gibbs, Christopher; Jervis, Rhodri; McMillan, Paul F; Wang, Xiaochen; Brett, Daniel J L

    2014-04-01

    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.

  11. 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 polyol

  12. Dynamic structural disorder in supported nanoscale catalysts.

    Science.gov (United States)

    Rehr, J J; Vila, F D

    2014-04-01

    We investigate the origin and physical effects of "dynamic structural disorder" (DSD) in supported nano-scale catalysts. DSD refers to the intrinsic fluctuating, inhomogeneous structure of such nano-scale systems. In contrast to bulk materials, nano-scale systems exhibit substantial fluctuations in structure, charge, temperature, and other quantities, as well as large surface effects. The DSD is driven largely by the stochastic librational motion of the center of mass and fluxional bonding at the nanoparticle surface due to thermal coupling with the substrate. Our approach for calculating and understanding DSD is based on a combination of real-time density functional theory/molecular dynamics simulations, transient coupled-oscillator models, and statistical mechanics. This approach treats thermal and dynamic effects over multiple time-scales, and includes bond-stretching and -bending vibrations, and transient tethering to the substrate at longer ps time-scales. Potential effects on the catalytic properties of these clusters are briefly explored. Model calculations of molecule-cluster interactions and molecular dissociation reaction paths are presented in which the reactant molecules are adsorbed on the surface of dynamically sampled clusters. This model suggests that DSD can affect both the prefactors and distribution of energy barriers in reaction rates, and thus can significantly affect catalytic activity at the nano-scale. PMID:24712802

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-10-20

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

  14. 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.

  15. 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.

  16. 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.

  17. Synthesis, characterization and hydrotreating performance of supported tungsten phosphide catalysts

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Supported tungsten phosphide catalysts were prepared by temperature-programmed reduction of their precursors (supported phospho-tungstate catalysts) in H2 and characterized by X-ray diffraction (XRD),BET,temperature-programmed desorption of ammonia (NH3-TPD) and X-ray photoelectron spectroscopy (XPS).The reduction-phosphiding processes of the precursors were investigated by thermogravimetry and differential thermal analysis (TG-DTA) and the suitable phosphiding temperatures were defined.The hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) activities of the catalysts were tested by using thiophene,pyridine,dibenzothiophene,carbazole and diesel oil as the feed-stock.The TiO2,γ-Al2O3 supports and the Ni,Co promoters could remarkably increase and stabilize active W species on the catalyst surface.A suitable amount of Ni (3%-5%),Co (5%-7%) and V (1%-3%) could increase dispersivity of the W species and the BET surface area of the WP/γ-Al2O3 catalyst.The WP/γ-Al2O3 catalyst possesses much higher thiophene HDS and carbazole HDN activities and the WP/TiO2 catalyst has much higher dibenzothiophene (DBT) HDS and pyridine HDN activities.The Ni,Co and V can obviously promote the HDS activity and inhibit the HDN activity of the WP/γ-Al2O3 catalyst.The G-Ni5 catalyst possesses a much higher diesel oil HDS activity than the sulphided industrial NiW/γ-Al2O3 catalyst.In general,a support or promoter in the WP/γ-Al2O3 catalyst which can increase the amount and dispersivity of the active W species can promote its HDS and HDN activities.

  18. 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%).

  19. Graphene supported heterogeneous catalysts for Li-O2 batteries

    Science.gov (United States)

    Alaf, M.; Tocoglu, U.; Kartal, M.; Akbulut, H.

    2016-09-01

    In this study production and characterization of free-standing and flexible (i) graphene, (ii) α-MnO2/graphene, (iii) Pt/graphene (iv) α-MnO2/Pt/graphene composite cathodes for Li-air batteries were reported. Graphene supported heterogeneous catalysts were produced by a facile method. In order to prevent aggregation of graphene sheets and increase not only interlayer distance but also surface area, a trace amount multi-wall carbon nano tube (MWCNT) was introduced to the composite structure. The obtained composite catalysts were characterized by SEM, X-ray diffraction, N2 adsorption-desorption analyze and Raman spectroscopy. The electrochemical characterization tests including galvanostatic charge/discharge and electrochemical impedance spectroscopy (EIS) measurement of catalyst were carried out by using an ECC-Air test cell. These highly active graphene supported heterogeneous composite catalysts provide competitive properties relative to other catalyst materials for Li-air batteries.

  20. Oxidative desulfurization of synthetic diesel using supported catalysts. Part 3. Support effect on vanadium-based catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Cedeno-Caero, Luis; Gomez-Bernal, Hilda; Fraustro-Cuevas, Adriana; Guerra-Gomez, Hector D.; Cuevas-Garcia, Rogelio [UNICAT, Facultad de Quimica, Universidad Nacional Autonoma de Mexico, Cd. Universitaria 04510, Mexico D.F. (Mexico)

    2008-04-15

    Oxidesulfurization (ODS) of benzothiophenic compounds prevailing in diesel was conducted with hydrogen peroxide in presence of various catalysts, using a model diesel and actual diesel fuel. ODS activities of dibenzothiophenes (DBTs) in hexadecane for a series of V{sub 2}O{sub 5} catalysts supported on alumina, titania, ceria, niobia and silica, were evaluated. Results show that the oxidation activity of DBTs depends on the support used. It was observed that the sulfone yield is not proportional to textural properties or V content. For all catalysts, ODS of benzothiophene (BT), dibenzothiophene (DBT), 4-methyl dibenzothiophene (4-MDBT) and 4,6-dimethyl dibenzothiophene (4,6-DMDBT) decreased in the following order: DBT > 4-MDBT > 4,6-DMDBT > BT. This trend does not depend on the catalyst used or the textural properties of the catalysts and supports. In presence of indole ODS activities diminish, except with catalysts supported on alumina-titania mixed oxide, whereas with V{sub 2}O{sub 5}/TiO{sub 2} catalyst the performance is the highest. ODS of Mexican diesel fuel was carried out in presence of this catalyst and S level was diminished in about 99%. (author)

  1. 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.

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

    Science.gov (United States)

    Jiang, Haibin; Lu, Shuliang; Zhang, Xiaohong; Dai, Wei; Qiao, Jinliang

    2016-01-01

    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.

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

    Science.gov (United States)

    Jiang, Haibin; Lu, Shuliang; Zhang, Xiaohong; Dai, Wei; Qiao, Jinliang

    2016-01-01

    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. PMID:27347922

  4. Heterogenization of Homogeneous Catalysts: the Effect of the Support

    Energy Technology Data Exchange (ETDEWEB)

    Earl, W.L.; Ott, K.C.; Hall, K.A.; de Rege, F.M.; Morita, D.K.; Tumas, W.; Brown, G.H.; Broene, R.D.

    1999-06-29

    We have studied the influence of placing a soluble, homogeneous catalyst onto a solid support. We determined that such a 'heterogenized' homogeneous catalyst can have improved activity and selectivity for the asymmetric hydrogenation of enamides to amino acid derivatives. The route of heterogenization of RhDuPhos(COD){sup +} cations occurs via electrostatic interactions with anions that are capable of strong hydrogen bonding to silica surfaces. This is a novel approach to supported catalysis. Supported RhDuPhos(COD){sup +} is a recyclable, non-leaching catalyst in non-polar media. This is one of the few heterogenized catalysts that exhibits improved catalytic performance as compared to its homogeneous analog.

  5. 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.

  6. Synthesis Gas Production from Natural Gas on Supported Pt Catalysts

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Auto-thermal reforming of methane, combining partial oxidation and reforming of methane with CO2 or steam, was carried out with Pt/Al2O3, Pt/ZrO2 and Pt/CeO2 catalysts, in a temperature range of 300-900 ℃. The auto-thermal reforming occurs in two simultaneous stages, namely, total combustion of methane and reforming of the unconverted methane with steam and CO2, with the O2 conversion of 100% starting from 450 ℃. For combination with CO2 reforming, the Pt/CeO2 catalyst showed the lowest initial activity at 800 ℃, and the highest stability over 40 h on-stream. This catalyst also presented the best performance for the reaction with steam at 800 ℃. The higher resistance to coke formation of the catalyst supported on ceria is due to the metal-support interactions and the higher mobility of oxygen in the oxide lattice.

  7. Sorbitol hydrogenolysis to glycols by supported ruthenium catalysts

    Institute of Scientific and Technical Information of China (English)

    Inmaculada Murillo Leo; Manuel Lopez Granados; Jose Luis Garcia Fierro; Rafael Mariscal

    2014-01-01

    Supported Ru catalysts were prepared by wet impregnation to evaluate the role of different oxide supports (Al2O3, SiO2, TiO2, ZrO2) in sorbitol hydrogenolysis to glycols. X-ray diffraction, transmis-sion electron microscopy, hydrogen chemisorption, X-ray photoelectron spectroscopy, and NH3 temperature-programmed desorption were used to characterize the catalysts, which were active in the hydrogenolysis of sorbitol. The support affected both the physicochemical properties and cata-lytic behavior of the supported Ru particles. The characterization results revealed that the Ru/Al2O3 catalyst has a high surface acidity, partially oxidized Ru species on the surface, and a higher surface Ru/Al atomic ratio, which gave it the highest selectivity and yield to glycols.

  8. States of Carbon Nanotube Supported Mo-Based HDS Catalysts

    Institute of Scientific and Technical Information of China (English)

    Hongyan Shang; Chenguang Liu; Yongqiang Xu; Jieshan Qiu; Fei Wei

    2006-01-01

    The dispersion of the active phase and loading capacity of the Mo species on carbon nanotube (CNT) was studied by the XRD technique. The reducibility properties of Co-Mo catalysts in the oxide state over CNTs were investigated by TPR, while the sulfided Co-Mo/CNT catalysts were characterized by means of the XRD and LRS techniques. The activity and selectivity with respect to the hydrodesulfurization (HDS) performances on carbon nanotube supported Co-Mo catalysts were evaluated. It was found that the main active molybdenum species in the oxide state MoO3/CNT catalysts were MoO2, but not MoO3, as generally expected. The maximum loading before the formation of the bulk phase was lower than 6% (percent by mass, based on MoO3). TPR studies revealed that the active species in the oxide state Co-Mo/CNT catalysts were reduced more easily at relatively lower temperatures in comparison to those of the Co-Mo/γ-Al2O3 catalysts, indicating that the CNT support promoted or favored the reduction of the active species. The active species of a Co-Mo-0.7/CNT catalyst were more easily reduced than those of the Co-Mo/CNT catalysts with Co/Mo atomic ratios of 0.2, 0.35, and 0.5, respectively, suggesting that the Co/Mo atomic ratio has a great effect on the reducibility of the active species. It was found that the incorporation of cobalt improved the dispersion of the molybdenum species on the support, and a phenomenon of mobilization and re-dispersion had occurred during the sulfurization process, resulting in low valence state Mo3S4 and Co-MoS2.17 active phases. HDS measurements showed that the Co-Mo/CNT catalysts were more active than the Co-Mo/γ-Al2O3 ones for the desulfurization of DBT, and the hydrogenolysis/hydrogenation selectivity of the Co-Mo/CNT catalysts was also much higher than those of the Co-Mo/γ-Al2O3. The Co-Mo/CNT catalyst with a Co/Mo atomic ratio of 0.7 showed the highest activity, whereas the catalyst with a Co/Mo atomic ratio of 0.35 had the highest selectivity.

  9. 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.

  10. States of carbon nanotube supported Mo-based HDS catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Shang, Hongyan; Liu, Chenguang; Xu, Yongqiang [Key Laboratory of Catalysis, CNPC, College of Chemistry and Chemical Engineering, University of Petroleum, Dongying 257061 (China); Qiu, Jieshan [Carbon Research Laboratory, Center for Nano Materials and Science, Dalian University of Technology, 158 Zhongshan Road, P. O. Box 49, Dalian 116012 (China); Wei, Fei [Department of Chemical Engineering, Tsinghua University, Being, 100084 (China)

    2007-02-15

    As HDS catalysts, the supported catalysts including oxide state Mo, Co-Mo and sulfide state Mo on carbon nanotube (CNT) were prepared, while the corresponding supported catalysts on {gamma}-Al{sub 2}O{sub 3} were prepared as comparison. Firstly, the dispersion of the active phase and loading capacity of Mo species on CNT was studied by XRD and the reducibility properties of Co-Mo catalysts in oxide state over CNTs were investigated by TPR while the sulfide Co-Mo/CNT catalysts were characterized by XRD and LRS techniques. Secondly, the activity and selectivity of hydrodesulfurization (HDS) of dibenzothiophene with Co-Mo/CNT and Co-Mo/{gamma}-Al{sub 2}O{sub 3} were studied. It has been found that the main active molybdenum species in the oxide state MoO{sub 3}/CNT catalysts were MoO{sub 2}, rather than MoO{sub 3} as generally expected. The maximum loading before formation of the bulk phase was lower than 6%m (calculated in MoO{sub 3}). The TPR studies revealed that that active species in oxide state Co-Mo/CNT catalysts were more easily reduced at relatively lower temperatures in comparison to those in Co-Mo/{gamma}-Al{sub 2}O{sub 3}, indicating that the CNT support promoted the reduction of active species. Among 0-1.0 Co/Mo atomic ratio on Co-Mo/CNT, 0.7 has the highest reducibility. It shows that the Co/Mo atomic ratio has a great effect on the reducibility of active species on CNT and their HDS activities and that the incorporation of cobalt improved the dispersion of molybdenum species on CNT and mobilization. It was also found that re-dispersion could occur during the sulfiding process, resulting in low valence state Mo{sub 3}S{sub 4} and Co-MoS{sub 2.17} active phases. The HDS of DBT showed that Co-Mo/CNT catalysts were more active than Co-Mo/{gamma}-Al{sub 2}O{sub 3} and the hydrogenolysis/hydrogenation selectivity of Co-Mo/CNT catalyst was also much higher than Co-Mo/{gamma}-Al{sub 2}O{sub 3}. For the Co-Mo/CNT catalysis system, the catalyst with Co/Mo atomic

  11. Support effects on hydrotreating activity of NiMo catalysts

    International Nuclear Information System (INIS)

    The effect of the gamma alumina particle size on the catalytic activity of NiMoSx catalysts prepared by precipitation method of aluminum acetate at pH = 10 was studied. The structural characterization of the supports was measured by using XRD, pyridine FTIR-TPD and nitrogen physisorption. NiMo catalysts were characterized during the preparation steps (annealing and sulfidation) using transmission electron microscopy (TEM). Hydrogen TPR studies of the NiMo catalysts were also carried out in order to correlate their hydrogenating properties and their catalytic functionality. Catalytic tests were carried out in a pilot plant at 613, 633 and 653 K temperatures. The results showed that the rate constants of hydrodesulfurization (HDS), hydrodenitrogenation (HDN) and hydrodearomatizing (HDA) at 613-653 K decreased in the following order: A > B > C corresponding to the increase of NiMoS particle size associated to these catalysts

  12. Templating Routes to Supported Oxide Catalysts by Design

    Energy Technology Data Exchange (ETDEWEB)

    Notestein, Justin M [Northwestern Univ., Evanston, IL (United States); Northwestern Univ., Evanston, IL (United States). Center for Catalysis and Surface Science; Northwestern Univ., Evanston, IL (United States). Dept. of Chemical and Biological Engineering

    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 oxide catalysts for energy applications.

  13. 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

  14. 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.

  15. Sulfide Catalysts Supported on Porous Aromatic Frameworks for Naphthalene Hydroprocessing

    Directory of Open Access Journals (Sweden)

    Eduard Karakhanov

    2016-08-01

    Full Text Available This paper describes the first example of using porous aromatic frameworks as supports for sulfide catalysts for the hydrogenation of aromatic hydrocarbons. The synthesis of bimetallic Ni-W and Ni-Mo sulfides was performed by in situ decomposition of [(n-Bu4N]2[Ni(MeS42] (Me = W, Mo complexes, supported on mesoporous aromatic framework with a diamond-like structure. It is shown that the highest naphthalene conversions were achieved in the case of additional sulfidation with sulfur. After the reaction, catalysts were characterized by X-ray photoelectron spectroscopy and high-resolution transmission electron microscopy. The activity of synthesized catalysts has been studied using naphthalene as a model substrate. The materials used in this study were substantially active in hydrogenation and slightly in hydrocracking of naphthalene.

  16. Novel zeolite-supported rhodium catalysts for ethanol steam reforming

    Science.gov (United States)

    Campos-Skrobot, Fabiana C.; Rizzo-Domingues, Roberta C. P.; Fernandes-Machado, Nádia R. C.; Cantão, Mauricio P.

    Renewable bioethanol is an interesting hydrogen source for fuel cells through steam reforming, but its C-C bond promotes parallel reactions, mainly coke and by-products formation. In this way, good ethanol reforming catalysts are still needed, which explains current research and development efforts around the world. Most catalysts proposed for ethanol reforming are based on oxide-supported noble metals with surface area below 100 m 2 g -1 and reaction temperatures above 500 °C. Novel Rh and Rh-K catalysts supported on NaY zeolite with surface area above 440 m 2 g -1 are presented in this work. Reaction temperature was fixed at 300 °C and H 2O/EtOH molar ratio and reagent flow were varied. Ethanol conversion varied from 50 to 99%, with average increase of 50% due to K promoter, and hydrogen production yield achieved 68%.

  17. 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.

  18. Predicting catalyst-support interactions between metal nanoparticles and amorphous silica supports

    Science.gov (United States)

    Ewing, Christopher S.; Veser, Götz; McCarthy, Joseph J.; Lambrecht, Daniel S.; Johnson, J. Karl

    2016-10-01

    Metal-support interactions significantly affect the stability and activity of supported catalytic nanoparticles (NPs), yet there is no simple and reliable method for estimating NP-support interactions, especially for amorphous supports. We present an approach for rapid prediction of catalyst-support interactions between Pt NPs and amorphous silica supports for NPs of various sizes and shapes. We use density functional theory calculations of 13 atom Pt clusters on model amorphous silica supports to determine linear correlations relating catalyst properties to NP-support interactions. We show that these correlations can be combined with fast discrete element method simulations to predict adhesion energy and NP net charge for NPs of larger sizes and different shapes. Furthermore, we demonstrate that this approach can be successfully transferred to Pd, Au, Ni, and Fe NPs. This approach can be used to quickly screen stability and net charge transfer and leads to a better fundamental understanding of catalyst-support interactions.

  19. 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

  20. 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...

  1. 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...

  2. Highly active gauze-supported skeletal nickel catalysts

    OpenAIRE

    Fow, Kam Loon; Ganapathi, Murugan; Stassen, Ivo; Fransaer, Jan; Binnemans, Koen; De Vos, Dirk E.

    2013-01-01

    Gauze-supported skeletal nickel catalysts were prepared by electrodeposition of Ni–Zn alloys from an acetamide–DMSO2–NiCl2–ZnCl2 quaternary melt, followed by chemical or electrochemical leaching of zinc from the alloys. The activity and selectivity of the structured RANEY® nickel surpass those of commercial RANEY® nickel in the hydrogenation of acetophenone.

  3. Structural studies of supported tin catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Nava, Noel [Instituto Mexicano del Petroleo, Gerencia de Catalizadores (Mexico); Viveros, Tomas [Universidad Autonoma Metropolitana-Iztapalapa, Area de Ingenieria Quimica (Mexico)

    1999-11-15

    Tin oxide was supported on aluminium oxide, titanium oxide, magnesium oxide and silicon oxide, and the resulting interactions between the components in the prepared samples and after reduction were characterized by Moessbauer spectroscopy. It was observed that in the oxide state, tin is present as SnO{sub 2} on alumina, magnesia and silica, but on titania tin occupies Ti sites in the structure. After hydrogen treatment at high temperatures, tin is reduced from Sn(4) to Sn(2) on alumina and titania; it is reduced from Sn(4) to Sn(0) on silica, and is practically not reduced on magnesia. These results reveal the degree of interaction between tin and the different supports studied.

  4. Characterization and Dehydrogenation Activity of SBA-15 and HMS Supported Chromia Catalysts

    Institute of Scientific and Technical Information of China (English)

    YUE,Hong-Yong(乐洪咏); ZHENG,Bo(郑波); YUE,Ying-Hong(乐英红); ZHANG,Xue-Zheng(张雪峥); HUA,Wei-Ming(华伟明); GAO,Zi(高滋)

    2002-01-01

    SBA-15 and HMS supported chromia catalysts were prepared and characterized. Chromia is highly dispersed on the mesoporous supports when its loading is ≤7 wt%. The supported catalysts display high activity, selectivity and stability for dehydrogenation of ethyibenzene and propane. ESR measurement of the catalysts before and after reaction shows that the active species for dehydrogenation reaction might be Cr3 + species on the catalyst surface, and the activity of the catalyst is probably correlated with the dispersion of Cr3+ species.

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

    OpenAIRE

    Mansor, N.; Jorge, A. B.; Corà, F.; Gibbs, C.; Jervis, R.; Mcmillan, P. F.; X. Wang; Brett, D. J.

    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...

  6. Hydrogenolysis of sugar beet fiber by supported metal catalyst

    OpenAIRE

    Guha, Samar K.; Kobayashi, Hirokazu; Hara, Kenji; Kikuchi, Hiroto; Aritsuka, Tsutomu; Fukuoka, Atsushi

    2011-01-01

    Sugar beet fiber is an agricultural by-product in the sugar manufacturing and an available biomass source with a rich hemicellulose component. So far, there has been no report on the catalytic conversion of the beet fiber for the synthesis of chemicals. In this work, the hydrogenolysis of the beet fiber was studied by using supported metal catalysts under pressurized hydrogen conditions. Activated carbon supported Ru was found to show the highest catalytic activity to give arabitol as a major...

  7. 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

  8. Autothermal Reforming of n-Hexane over Supported Metal Catalysts

    OpenAIRE

    Brandmair, Maria

    2007-01-01

    Autothermal reforming was investigated with hexane as a model compound for alkanes. Therefore, oxide supports (CeO2, ZrO2, Zr0.92Y0.08O2, gamma-Al2O3) were impregnated with metals (Ni, Pt und Rh) and their physico-chemical and catalytic properties were studied. Alumina supported rhodium showed the best and most stable performance. Detailed kinetic studies were performed on rhodium supported monolithic alumina in comparison with a monolithic industrial catalyst in a wide range of reaction temp...

  9. Coarse-pored ceramic supports for pyrolysis catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Potapova, L.L.; Cherches, B.Kh.; Egiazarov, Yu.G.

    1988-03-20

    One promising trend in improvement of pyrolysis of hydrocarbon feedstocks is the use of heterogeneous catalysts in the process. The industrial use of highly effective catalysts would result in substantially increased product yields and in decrease of energy consumption in comparison with the requirements of drastic thermal processes. The aims of the present work were to obtain a mechanically strong coarse-pored ceramic support for pyrolysis catalysts and to study the influence of various factors on formation of its structure. The support material was made from an industrial ceramic mass of the following composition (%): koalin 30, plastic refractory clay 21, quartz 32, pegmatite 17. Various additives were used for formation of a porous structure: noncombustible highly porous (pumice, claydite), partially combustible (shungite), and completely combustible (SKT) activated carbon). The authors results show that 15 mass % of SKT carbon (particle size 0.1-0.2 mm) and 1-2 mass % of sodium trimetaphosphate should be added to the ceramic mass. The crushing strength of the resultant support samples reaches 550-630 kg/cm/sup 2/, with 34-35% porosity. Under the optimal conditions of pyrolysis of a straight-run gasoline fraction the catalyst obtained by deposition of 12 mass % of In/sub 2/O/sub 3/ and 4% K/sub 2/O on the synthesized support gives a yield of 39-41 mass % of ethylene and 61-62 mass % of unsaturated C/sub 2/-C/sub 4/ hydrocarbons, with 88-90 mass % gasification.

  10. 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(....... Based on these results the aqueous and the homogeneous nature of the SAP catalysts are discussed....

  11. Ammoxidation of Substituted Toluenes on Silica-Supported VPO Catalysts

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The ammoxidation of substituted toluenes to their corresponding nitriles over silica-supported vanadium phosphorus oxide (VPO/SiO2) catalysts has been studied. The effects of carrier silica, the addition of phosphorus, the substituents and the loadings have been discussed. Compared with unsupported VPO, the VPO/SiO2 catalysts have higher catalytic activity for ammoxidation of substituted toluenes and much lower reaction temperature. XRD shows that vanadium phosphorus oxides exist as amorphous phase and disperse to a high degree on the silica surface in 10 % loading catalyst. When the loadings are over 10 %, the crystalline α-VOPO4 would emerge, which would decrease the yield and selectivity. Additional phosphorus can form composite oxides with vanadia and play concerted catalytic function, which increase the selectivity of nitriles remarkably. Different substituents or same substituents on diffetent positions have different influences because of the variant electronic stability of intermediates, the hindered accessibility of methyl group or the chemisorption state of the substrate molecule on the electrophilic catalyst surface.

  12. One-pot synthesis of network supported catalyst using supramolecular gel as template

    Institute of Scientific and Technical Information of China (English)

    Yong Liang; Li Ming Tang; Yu Xia; Kai Chen; Bo Tian Li; Xin Jin

    2010-01-01

    A simple and general strategy is described for preparing network supported catalyst through a one-pot synthetic procedure using supramolecular gel as template. This procedure directly attaches iigand to support during fabricating the support. Using this strategy, supported CuBr/di-(2-picolyl)amine catalyst with U-shaped fibrillar network was prepared and used in atom transfer radical polymerization of methyl methacrylate. XPS and SEM characterization of the catalyst revealed homogeneous distribution of ligand, sufficient reactive sites, adequate mechanical strength and macroporosity. The polymerization results demonstrated high activity and reusability of such catalyst. This strategy might be extended to other supported catalysts used in column reactors.

  13. 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. PMID:20728274

  14. Electrochemical Catalyst-Support Effects and Their Stabilizing Role for IrOx Nanoparticle Catalysts during the Oxygen Evolution Reaction.

    Science.gov (United States)

    Oh, Hyung-Suk; Nong, Hong Nhan; Reier, Tobias; Bergmann, Arno; Gliech, Manuel; Ferreira de Araújo, Jorge; Willinger, Elena; Schlögl, Robert; Teschner, Detre; Strasser, Peter

    2016-09-28

    Redox-active support materials can help reduce the noble-metal loading of a solid chemical catalyst while offering electronic catalyst-support interactions beneficial for catalyst durability. This is well known in heterogeneous gas-phase catalysis but much less discussed for electrocatalysis at electrified liquid-solid interfaces. Here, we demonstrate experimental evidence for electronic catalyst-support interactions in electrochemical environments and study their role and contribution to the corrosion stability of catalyst/support couples. Electrochemically oxidized Ir oxide nanoparticles, supported on high surface area carbons and oxides, were selected as model catalyst/support systems for the electrocatalytic oxygen evolution reaction (OER). First, the electronic, chemical, and structural state of the catalyst/support couple was compared using XANES, EXAFS, TEM, and depth-resolved XPS. While carbon-supported oxidized Ir particle showed exclusively the redox state (+4), the Ir/IrOx/ATO system exhibited evidence of metal/metal-oxide support interactions (MMOSI) that stabilized the metal particles on antimony-doped tin oxide (ATO) in sustained lower Ir oxidation states (Ir(3.2+)). At the same time, the growth of higher valent Ir oxide layers that compromise catalyst stability was suppressed. Then the electrochemical stability and the charge-transfer kinetics of the electrocatalysts were evaluated under constant current and constant potential conditions, where the analysis of the metal dissolution confirmed that the ATO support mitigates Ir(z+) dissolution thanks to a stronger MMOSI effect. Our findings raise the possibility that MMOSI effects in electrochemistry-largely neglected in the past-may be more important for a detailed understanding of the durability of oxide-supported nanoparticle OER catalysts than previously thought.

  15. 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.

  16. 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.

  17. 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.

  18. Studies of Immobilized Homogeneous Metal Catalysts on Silica Supports

    Energy Technology Data Exchange (ETDEWEB)

    Keith James Stanger

    2003-05-31

    The tethered, chiral, chelating diphosphine rhodium complex, which catalyzes the enantioselective hydrogenation of methyl-{alpha}-acetamidocinnamate (MAC), has the illustrated structure as established by {sup 31}P 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]{sub 4}, [Rh(COD){sub 2}]{sup +}BF{sub 4}{sup -}, [Rh(COD)Cl]{sub 2}, and RhCl{sub 3} {center_dot} 3H{sub 2}O, adsorbed on SiO{sub 2} are optimally activated for toluene hydrogenation by pretreatment with H{sub 2} at 200 C. The same complexes on Pd-SiO{sub 2} 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(CH{sub 2}){sub 3}s-]Re(O)(Me)(PPh{sub 3}) 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.

  19. Sustainable catalyst supports for carbon dioxide gas adsorbent

    Science.gov (United States)

    Mazlee, M. N.

    2016-07-01

    The adsorption of carbon dioxide (CO2) become the prime attention nowadays due to the fact that increasing CO2 emissions has been identified as a contributor to global climate change. Major sources of CO2 emissions are thermoelectric power plants and industrial plants which account for approximately 45% of global CO2 emissions. Therefore, it is an urgent need to develop an efficient CO2 reduction technology such as carbon capture and storage (CCS) that can reduce CO2 emissions particularly from the energy sector. A lot of sustainable catalyst supports have been developed particularly for CO2 gas adsorbent applications.

  20. The effect of catalyst support on the RWGS reaction

    International Nuclear Information System (INIS)

    'Full text:' Methane steam reforming is generally applied in order to produce synthesis gas mainly consist of hydrogen and carbon monoxide for later utilization in SOFC. This reaction is always carried out with the water gas shift reaction over a catalyst at elevated temperatures resulting in some carbon dioxide production. The CO/CO2 production selectivity strongly depends on the influence of water gas shift reaction. It was observed that the reactivity of this reaction depended on the type of support material. Stabilities, activities, and kinetics of the reverse water gas shift reaction (RWGS) for commercial nickel on CeO2, ZrO2, CeO2-ZrO2, TiO2, MgO, and Al2O3 supports were studied in order to observe the influence of the support on this reaction. According to the experiment, the activities of Ni/CeO2 toward the reverse water gas shift reaction (RWGS) were very high, and reached equilibrium level at approximately 600oC (where the conversion of CO2 was closed to 1). Other oxide supports provided lower activities toward this reaction. It was observed that the activity of Ni/Al2O3 toward this reaction was the lowest. The kinetics of this reaction was also studied. Carbon dioxide presented positive effect on the reverse water gas shift reaction. The reaction orders in carbon dioxide were observed to be positive partial value between 0-1. It slightly decreased with increasing temperature for Ni/ CeO2 and Ni/CeO2-ZrO2, whereas it seemed to be independent of the operating temperature for other materials in the range of conditions studied. Hydrogen also showed positive effect on the reverse water gas shift reaction for all materials. The reaction order in hydrogen for all materials was observed to be the positive value and less than one for the range of conditions studied. The approximate values for all catalysts were between 0.45-0.65, and seemed to be independent of the operating temperature. The estimated values of the apparent activation energy for RWGS reaction

  1. 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...

  2. Polystyrene-supported chloroaluminate ionic liquid as a new heterogeneous Lewis acid catalyst for Knoevenagel condensation

    Institute of Scientific and Technical Information of China (English)

    Kaveh Parvanak Boroujeni; Mina Jafarinasab

    2012-01-01

    Non-hygroscopic polystyrene-supported chloroaluminate ionic liquid was prepared from the reaction of Merrifield resin with 1-methylimidazole followed by reaction with aluminum chloride.This Lewis acidic ionic liquid is environmentally friendly heterogeneous catalyst for the Knoevenagel condensation of aromatic and aliphatic aldehydes with ethyl cyanoacetate.The catalyst is stable (as a bench top catalyst) and reusable.

  3. 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.

  4. Controlled Radical Polymerization of Methyl Methacrylate Catalyzed by Hybrid Supported Iron Catalyst

    Institute of Scientific and Technical Information of China (English)

    LI Zhong-hui; ZHANG Yong-ming; XUE Min-zhao; ZHOU Lei; LIU Yan-gang

    2005-01-01

    A supported iron catalyst, which was prepared by anchoring FeCl2/FeCl3 on the cross-linking macroporous polyacrylate ion exchange resin, was evaluated via the controlled radical polymerization. When a small amount of CuCl2/Me6TREN was added, the controllability of the polymerization over the iron-mediated catalyst was significantly improved(Mw/Mn=1.23-1.73), affording a polymer with a low residual metal via a simple catalyst separation procedure. After suitable regeneration, the supported iron catalyst could also be recycled. UV-Vis analysis showed that the additional copper catalyst could facilitate the radical deactivation process.

  5. STUDY ON 1-HEXENE POLYMERIZATION BASED ON ZIEGLER-NATTA CATALYSTS WITH DOPED SUPPORT

    Institute of Scientific and Technical Information of China (English)

    Xue Jiang; Zhi-qiang Fan

    2004-01-01

    A series of Ti/Mg supported catalysts are prepared by using ball-milled mixtures of MgCl2-ethanol adducts and NaCl as supports, and 1-hexene polymerizations catalyzed by the novel catalysts are studied. It is found that the molecular weight distribution of poly(1-hexene) becomes apparently narrower when catalysts with doped supports are used, indicating that changing the structure of the support is an effective way to regulate the active center distribution of heterogeneous Ziegler-Natta catalyst.

  6. Novel Carbon Nanotubes-supported NiB Amorphors Alloy Catalyst for Benzene Hydrogenation

    Institute of Scientific and Technical Information of China (English)

    Mei Hua YANG; Rong Bin ZHANG; Feng Yi LI

    2004-01-01

    The NiB amorphous alloy catalysts supported on CNTs and alumina were prepared by impregnation and chemical reduction. The gas-phase benzene hydrogenation was used as a probe reaction to evaluate the catalytic activity. The result showed that the NiB amorphous alloy catalyst supported on carbon nanotubes exhibited higher activity than that supported on alumina.

  7. Metallocene supported core@LDH catalysts for slurry phase ethylene polymerisation.

    Science.gov (United States)

    Buffet, Jean-Charles; Byles, Coral F H; Felton, Ryan; Chen, Chunping; O'Hare, Dermot

    2016-03-14

    We report the synthesis of solid catalysts based on a zirconocene supported on either silica@AMO-LDH or zeolite@AMO-LDH for the slurry phase polymerisation of ethylene. The hybrid catalysts demonstrate synergistic effects in which the polymerisation activity is up to three times higher than the zirconocene supported on analogous single phase silica or zeolite supports.

  8. POLYMER-SUPPORTED LEWIS ACID CATALYSTS. VI. POLYSTYRENE-BONDED STANNIC CHLORIDE CATALYST

    Institute of Scientific and Technical Information of China (English)

    RAN Ruicheng; FU Diankui

    1991-01-01

    A polystyrene-bonded stannic chloride catalyst was synthesized by the method of lithium polystyryl combined with stannic chloride. This catalyst is a polymeric organometallic compound containing 0.25 mmol Sn(IV)/g catalyst. The catalyst showed sufficient stability and catalytic activity in organic reaction such as esterification, acetalation and ketal formation, and it could be reused many times without losing its catalytic activity.

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

    Science.gov (United States)

    Leelavathi, Annamalai; Bhaskara Rao, Thumu Udaya; Pradeep, Thalappil

    2011-12-01

    Quantum clusters (QCs) of silver such as Ag7(H2MSA)7, Ag8(H2MSA)8 (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.

  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. Ti-Si composite oxide-supported cobalt catalysts for CO2 hydrogenation

    Institute of Scientific and Technical Information of China (English)

    Jakrapan Janlamool; Piyasan Praserthdam; Bunjerd Jongsomjit

    2011-01-01

    In the present work,different silica-based supported cobalt (Co) catalysts were synthesized and used for CO2 hydrogenation for methanation.Different supports,such as SSP,MCM-41,TiSSP and TiMCM were used to prepare Co catalysts with 20 wt% Co loading.The supports and catalysts were characterized by means of N2 physisorption,XRD,SEM/EDX,XPS,TPR and CO chemisorption.It is found that after calcination of catalysts,Ti is present in the form of anatase.The introduction of Ti plays important roles in the properties of Co catalysts by.(i) facilitating the reduction of Co oxides species which are strongly interacted with support,(ii) preventing the formation of silicate compounds,and (iii) inhibiting the RWGS reaction.Based on CO2 hydrogenation,the CoTiMCM catalyst exhibites the highest activity and stability.

  12. Organophilic worm-like ruthenium nanoparticles catalysts by the modification of CTAB on montmorillonite supports.

    Science.gov (United States)

    Zhou, Limei; Qi, Xiaolong; Jiang, Xiaohui; Zhou, Yafen; Fu, Haiyan; Chen, Hua

    2013-02-15

    A supported Ru catalyst was prepared by using cetyltrimethylammonium bromide (CTAB) intercalated montmorillonite as the supporting matrix. The as-prepared Ru catalyst was subsequently characterized by XRD, XPS, N(2) sorption, TEM, and dispersibility measurement. The results showed that the Ru nanoparticles were in the modified montmorillonite interlayers, and the morphology of Ru nanoparticle was worm-like. Moreover, this supported Ru catalyst could be well dispersed in organic solvents such as toluene. The catalyst exhibited high activity and selectivity in the hydrogenation of quinoline even without stirring. PMID:23141762

  13. Oxide-supported metal clusters: models for heterogeneous catalysts

    International Nuclear Information System (INIS)

    Understanding the size-dependent electronic, structural and chemical properties of metal clusters on oxide supports is an important aspect of heterogeneous catalysis. Recently model oxide-supported metal catalysts have been prepared by vapour deposition of catalytically relevant metals onto ultra-thin oxide films grown on a refractory metal substrate. Reactivity and spectroscopic/microscopic studies have shown that these ultra-thin oxide films are excellent models for the corresponding bulk oxides, yet are sufficiently electrically conductive for use with various modern surface probes including scanning tunnelling microscopy (STM). Measurements on metal clusters have revealed a metal to nonmetal transition as well as changes in the crystal and electronic structures (including lattice parameters, band width, band splitting and core-level binding energy shifts) as a function of cluster size. Size-dependent catalytic reactivity studies have been carried out for several important reactions, and time-dependent catalytic deactivation has been shown to arise from sintering of metal particles under elevated gas pressures and/or reactor temperatures. In situ STM methodologies have been developed to follow the growth and sintering kinetics on a cluster-by-cluster basis. Although several critical issues have been addressed by several groups worldwide, much more remains to be done. This article highlights some of these accomplishments and summarizes the challenges that lie ahead. (topical review)

  14. Nafion-Teflon bimembrane-supported palladium catalysts for Suzuki coupling reactions

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Nafion-Teflon bimembrane was used as an efficient support for the preparation and application of heterogeneous palladium catalysts. The supported palladium catalysts exhibit high activity and stability in the Suzuki cross-coupling of aryl bromides with arylboronic acids to afford the corresponding biaryls in good to excellent yields, and can be readily recovered and reused several times without significant loss of activity.

  15. 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.

  16. CARBON NANOTUBES VIA METHANE DECOMPOSITION ON AN ALUMINA SUPPORTED COBALT AEROGEL CATALYST

    Institute of Scientific and Technical Information of China (English)

    Lingyu Piao; Jiuling Chen; Yongdan Li

    2003-01-01

    An alumina-supported cobalt aerogel catalyst prepared from a sol-gel and a supercritical drying method was used in the catalytic decomposition of methane. The physical-chemical properties of the catalyst were characterized and its activity for methane decomposition was investigated. The effects of calcination and reaction temperatures on the activity of the catalyst and the morphology of the carbon nanotubes produced were discussed. A CoAl2O4 spinel structure formed in the calcined catalyst. The quantity of the nanotubes produced in the reaction increases with the amount of cobalt in the reduced catalyst. A higher reaction temperature leads to a higher reaction rate, though faster deactivation of the catalyst occurs with the change. The carbon nanotubes grown on the catalyst have smooth walls and uniform diameter distribution.

  17. PROPERTIES OF POLYMER SUPPORTED Ni-Cu BIMETALLIC CATALYSTS PREPARED BY SOLVATED METAL ATOM IMPREGNATION

    Institute of Scientific and Technical Information of China (English)

    WU Shihua; ZHU Changying; HUANG Wenqiang

    1996-01-01

    D-72 resin supported nickel-copper catalysts prepared by solvated metal atom impregnation (SMAI) were studied by magnetic measurements and X-ray photoelectron spectroscopy (XPS). The Ni particles on the catalysts are very highly dispersed and display superparamagnetic behaviour. Ni-Cu alloy clusters were found to be formed. The surface compositions are different from the bulk concentrations. In contrast with the surface enrichment in copper generally observed on conventional Ni-Cu catalysts, the surfaces of these catalysts are enriched in nickel. The nickel is in both zero and valent states, while copper is mainly in metallic state. Catalytic data show that the formation of Ni-Cu alloy clusters has a profound effect on the catalytic activities of the catalysts in the hydrogenation of furfural. The activity of the Ni:Cu ratio of one bimetallic catalysts is much higher than that of the Ni or Cu monometallic catalyst.

  18. 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.

  19. Hydrogenation of ortho-nitrochlorobenzene on activated carbon supported platinum catalysts

    Institute of Scientific and Technical Information of China (English)

    JIANG Cheng-jun; YIN Hong; CHEN Zhi-rong

    2005-01-01

    Platinum/carbon catalyst is one of the most important catalysts in hydrogenation of ortho-nitrochlorobenzene to 2,2'-dichlorohydrazobenzene. The preparation process and the supports of catalysts are studied in this paper. Raw materials and preparation procedure of the activated carbon have great influences on the compositions and surface structure of platinum/carbon catalysts. Platinum catalysts supported on activated carbon with high purity, high surface area, large pore volume and appropriate pore structure usually exhibit higher activities for hydrogenation of ortho-nitrochlorobenzene to 2,2'-dichlorohydrazobenzene.The catalyst prepared from H2PtCl6 with pH=3 shows greater catalytic performance than those prepared under other conditions.

  20. 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)

  1. 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.

  2. Mesoporous zeolite SBA-15 supported nickel diimine catalysts for ethylene polymerization

    Institute of Scientific and Technical Information of China (English)

    GUO Chao; ZHANG Dao; JIN Guoxin

    2004-01-01

    The novel mesoporous zeolite SBA-15 is successfully used as the support to immobilize late-transition metal nickel diimine catalyst, both in physical and chemical methods, EA, ICP, FT-IR and XRD are applied to characterizing these supported catalysts. The results of ethylene polymerization reveal that these supported catalysts have high catalytic activity as their homogenous counterpart does, moreover, polyethylene with a fibrous morphology is produced due to the channel effect of support, and both the molecular weight and molecular weight distributions of polymers are increased greatly.

  3. Effects of carrier and Mn loading on supported manganese oxide catalysts for catalytic combustion of methane

    Institute of Scientific and Technical Information of China (English)

    Jinyan Hu; Wei Chu; Limin Shi

    2008-01-01

    Supported manganese oxide catalysts were prepared by incipient wetness impregnation method for methane cat-alytic combustion, and effects of the support (Al2O3, SiO2 and TiO2) and Mn loading were investigated. These catalysts were characterized with N2 adsorption, X-ray diffraction, X-ray photoelectron spectroscopy and temperature-programmed reduction techniques. Methane conversion varied in a large range depending on supports or Mn loading. Al2O3 supported 15% Mn cata-lyst exhibited better activity toward methane catalytic oxidation. The manganese state and oxygen species played an important role in the catalytic performance.

  4. Silica supported Brӧnsted acids as catalyst in organic transformations:A comprehensive review

    Institute of Scientific and Technical Information of China (English)

    Manpreet Kaur; Sahil Sharma; Preet M. S. Bedi

    2015-01-01

    Brӧnsted acid catalysts have been used in a number of organic transformations. To overcome limi‐tations, such as toxicity, volatility, high price and hazardous nature of the conventional methods, the catalysts are adsorbed on silica gel to give the benefits and advantages of ready availability, simple work‐up procedure, long catalytic life, environment‐friendliness, good to excellent yields and recy‐clability. The uses of such catalysts have gained importance worldwide. This article describes some of the important silicated catalysts, namely, heteropolyacids, polyphosphoric acid, perchloric acid, fluoroboric acid, and silicated sulphuric acid. These catalysts have been used in a number of organic reactions to yield compounds that are important in the chemical and pharmaceutical industries. We summarize the beneficial effects of these catalysts and the reports that have been published on them in the past several years. In the present review, the description of the catalysts are introduced followed by a recent research history, and a comparison between the silica supported catalysts and other (polymer) supported catalysts. The article ends up giving the advantages of these catalytic systems over the conventional catalyst.

  5. Altervalent cation-doped MCM-41 supported palladium catalysts and their catalytic properties

    OpenAIRE

    HAIHUI JIANG; LIGANG GAI; YAN TIAN

    2011-01-01

    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 enhanc...

  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. 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......NOx'ed flue gas. The vanadium (IV) compound K4(VO)3(SO4)5 precipitated during all the investigated conditions hence causing catalyst deactivation. Hysteresis behavior of both the catalytic activity and the V(IV) content was observed during reheating....

  8. Supported, Alkali-Promoted Cobalt Oxide Catalysts for NOx Removal from Coal Combustion Flue Gases

    Energy Technology Data Exchange (ETDEWEB)

    Morris D. Argyle

    2005-12-31

    A series of cobalt oxide catalysts supported on alumina ({gamma}-Al{sub 2}O{sub 3}) were synthesized with varying contents of cobalt and of added alkali metals, including lithium, sodium, potassium, rubidium, and cesium. Unsupported cobalt oxide catalysts and several cobalt oxide catalysts supported ceria (CeO{sub 2}) with varying contents of cobalt with added potassium were also prepared. The catalysts were characterized with UV-visible spectroscopy and were examined for NO{sub x} decomposition activity. The CoO{sub x}/Al{sub 2}O{sub 3} catalysts and particularly the CoO{sub x}/CeO{sub 2} catalysts show N{sub 2}O decomposition activity, but none of the catalysts (unsupported Co{sub 3}O{sub 4} or those supported on ceria or alumina) displayed significant, sustained NO decomposition activity. For the Al{sub 2}O{sub 3}-supported catalysts, N{sub 2}O decomposition activity was observed over a range of reaction temperatures beginning about 723 K, but significant (>50%) conversions of N{sub 2}O were observed only for reaction temperatures >900 K, which are too high for practical commercial use. However, the CeO{sub 2}-supported catalysts display N{sub 2}O decomposition rates similar to the Al{sub 2}O{sub 3}-supported catalysts at much lower reaction temperatures, with activity beginning at {approx}573 K. Conversions of >90% were achieved at 773 K for the best catalysts. Catalytic rates per cobalt atom increased with decreasing cobalt content, which corresponds to increasing edge energies obtained from the UV-visible spectra. The decrease in edge energies suggests that the size and dimensionality of the cobalt oxide surface domains increase with increasing cobalt oxide content. The rate data normalized per mass of catalyst that shows the activity of the CeO{sub 2}-supported catalysts increases with increasing cobalt oxide content. The combination of these data suggest that supported cobalt oxide species similar to bulk Co{sub 3}O{sub 4} are inherently more active than

  9. 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)

  10. Ammoxidation of 2-methyl pyrazine on supported ammonium salt of 12-molybdophosphoric acid catalysts: The influence of nature of support

    Indian Academy of Sciences (India)

    Katabathini Narasimharao; B Hari Babu; N Lingaiah; P S Sai Prasad; Shaeel A Al-Thabaiti

    2014-03-01

    Influence of the nature of support on the formation of catalytically active species was investigated to clarify the key factor for the synthesis of supported ammonium salt of 12-molybdophosphoric acid (AMPA) catalyst which maintains the activity of ammoxidation during 2-methylpyrazine reaction.With this aim, different loadings of niobia-, silica- and alumina-, supported AMPA catalysts were prepared. The AMPA loading was varied in the range of 5-25 wt%. The synthesized solids were characterized by nitrogen adsorption for BET surface area, XRD and 31P MAS NMR techniques. All the AMPA-supported samples are poorly crystalline even after 25 wt% AMPA loading. Investigations using 31P MAS NMR spectroscopy of samples revealed that Keggin ion existed as at least five different species on the supports. The investigated properties were acidity of the support and amount of AMPA loading on the support. Active sites for the ammoxidation of MP on supported AMPA catalysts seem to be the interacted and/or the lacunary species.Maximum catalytic activity could be obtained at lower loadings with AMPA deposited on acidic supports whereas the less acidic supports require higher loading. It was found that in order to efficiently generate the active interactive species, the support must have an acidity which promotes the formation of support-AMPA interactive species. It is possible to enhance the catalytic activity of the supported AMPA catalyst for ammoxidation of 2-methylpyrazine by controlling the acidity of the support and AMPA loading on the support.

  11. Sulphur poisoning of palladium catalysts used for methane combustion: Effect of the support

    International Nuclear Information System (INIS)

    Four different supported palladium catalysts (using alumina, silica, zirconia and titania as supports), prepared by incipient wetness impregnation, were tested as catalysts for methane oxidation in presence of sulphur dioxide. The catalyst supported on zirconia showed the best performance, whereas the silica-supported one showed the fastest deactivation. Temperature-programmed desorption experiments of the poisoned catalysts suggest that SO2 adsorption capacity of the support plays a key role in the catalyst poisoning. In order to study the effect of promoters, expected to improve the thermal stability and thioresistance of the catalyst, commercial zirconia modified by yttrium and lantane was tested as supports. It was found that the presence of these promoters does not improve the performance of the zirconia-supported catalyst. A deactivation model - considering two different active sites (fresh and poisoning), pseudo-first order dependence on methane concentration and poisoning rate depending on sulphur concentration and fraction of non-poisoned palladium - was used for modelling the deactivation behaviour

  12. Ceria-Modified Clay Supported Palladium Catalysts for Complete Oxidation of Volatile Organic Compounds

    Institute of Scientific and Technical Information of China (English)

    Li Jinjun; Hao Zhengping; Hu Chun

    2004-01-01

    Ceria- and alumina-pillared interlayered clays were synthesized in the presence of PEO surfactant by using laponite clay as raw material.And the synthesized pillared clays were used as supports to load palladium catalysts for complete oxidation of benzene.Nitrogen adsorption/desorption experiments reveal that the pillared clays have higher tests show that ceria pillar exhibited promoting effect on the activity of the palladium catalysts, and ceria-pillared clay supported palladium catalyst catalyzed the complete oxidation of benzene at less than 250 ℃.The calcination temperature affects the activity of the catalysts significantly, and it is found that the optimal calcination temperature are 600 and 400 ℃ for ceria- and alumina-pillared clay supported palladium catalysts, respectively.

  13. 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)

  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. Carbon Nanofiber Supported Transition-Metal Carbide Catalysts for the Hydrodeoxygenation of Guaiacol

    NARCIS (Netherlands)

    Jongerius, A.; Gosselink, R.W.; Dijkstra, J.; Bitter, J.H.; Bruijnincx, P.C.A.; Weckhuysen, B.M.

    2013-01-01

    Hydrodeoxygenation (HDO) studies over carbon nanofiber-supported (CNF) W2C and Mo2C catalysts were performed on guaiacol, a prototypical substrate to evaluate the potential of a catalyst for valorization of depolymerized lignin streams. Typical reactions were executed at 55 bar hydrogen pressure ove

  16. Catalytic Performance of Bare Supporters and Supported KVO3 Catalysts for Cracking n-Butane to Produce Light Olefins

    Institute of Scientific and Technical Information of China (English)

    LuJiangyin; ZhaoZhen; XuChunming; ZhangPu

    2005-01-01

    Supported KVO3 catalysts were prepared by impregnating different kinds of.supporters (α-Al2O3,γ-Al2O3 and SiO2 powders) with a KVO3 solution. The activity of the bare supporters and supported catalysts were evaluated in a continuous micro-reactivity test unit, with n-butane as a raw material. The results show that KVO3 has no catalytic activity, but it can increase the selectivity to light olefins. The supporter of γ-Al2O3 has good catalytic performance for nbutane cracking when the reaction temperature is below 700℃.

  17. Stability and catalytic performance of vanadia supported on nanostructured titania catalyst in oxidative dehydrogenation of propane

    International Nuclear Information System (INIS)

    Highlights: • Vanadia supported on titanate nanotube shows enhanced dispersion of vanadia. • Deactivatoin during propane ODH related to the rutile development. • Titanate nanotube transfers to anatase due to calcinations and presence of vanadia. - Abstract: Titanate nanotubes with a high specific surface area were synthesized by the simple hydrothermal method and investigated as support for V2O5 catalyst in oxidative dehydrogenation of propane (ODP). The structures of pristine nanotubes as well as the prepared catalysts were investigated by XRD, Raman, FTIR, HRTEM, SEM, EDS, BET, and XPS techniques. The characterization of the as-synthesized nanotubes showed the synthesis of hydrogen titanate nanotube. The incipient wetness impregnation method was utilized to prepare VTNT-x (x = 5, 10, and 15 wt.% vanadia supported on nanotube) together with VTi5 (5 wt.% vanadia supported on Degussa P25). The anatase phase was developed in VTNT-x catalysts upon calcination along with specific surface area loss. Higher vanadia loading resulted in the lowering of support capacity in maintaining vanadia in dispersed state such that eventually crystalline vanadia appeared. The measured catalyst activity demonstrates that in spite of major support surface area loss in VTNT-5 catalyst, the propylene yield is superior in comparison with VTi5 catalyst. The catalyst activity can be correlated with maximum reduction temperature. Deactivation of VTi5 and VTNT-5 as well as VTNT-15 were studied for 3,000 min time-on-stream. It was found that the activity of VTNT-5 catalyst remain unchanged while a decline in catalytic activity observed in VTi5 and VTNT-15 catalysts. The development of rutile was considered as being a major element in the deactivation of the investigated catalysts which is influenced by the presence of vanadium and reaction atmosphere

  18. Stability and catalytic performance of vanadia supported on nanostructured titania catalyst in oxidative dehydrogenation of propane

    Energy Technology Data Exchange (ETDEWEB)

    Kootenaei, A.H. Shahbazi [Department of Chemical Engineering, College of Engineering, Tarbiat Modares University, P.O. Box 14115-143, Tehran (Iran, Islamic Republic of); Towfighi, J., E-mail: towfighi@modares.ac.ir [Department of Chemical Engineering, College of Engineering, Tarbiat Modares University, P.O. Box 14115-143, Tehran (Iran, Islamic Republic of); Khodadadi, A.; Mortazavi, Y. [Catalysis and Nanostructured Materials Laboratory, Oil and Gas Processing Center of Excellence, Department of Chemical Engineering, College of Engineering, University of Tehran, P.O. Box 11365-4563, Tehran (Iran, Islamic Republic of)

    2014-04-01

    Highlights: • Vanadia supported on titanate nanotube shows enhanced dispersion of vanadia. • Deactivatoin during propane ODH related to the rutile development. • Titanate nanotube transfers to anatase due to calcinations and presence of vanadia. - Abstract: Titanate nanotubes with a high specific surface area were synthesized by the simple hydrothermal method and investigated as support for V{sub 2}O{sub 5} catalyst in oxidative dehydrogenation of propane (ODP). The structures of pristine nanotubes as well as the prepared catalysts were investigated by XRD, Raman, FTIR, HRTEM, SEM, EDS, BET, and XPS techniques. The characterization of the as-synthesized nanotubes showed the synthesis of hydrogen titanate nanotube. The incipient wetness impregnation method was utilized to prepare VTNT-x (x = 5, 10, and 15 wt.% vanadia supported on nanotube) together with VTi5 (5 wt.% vanadia supported on Degussa P25). The anatase phase was developed in VTNT-x catalysts upon calcination along with specific surface area loss. Higher vanadia loading resulted in the lowering of support capacity in maintaining vanadia in dispersed state such that eventually crystalline vanadia appeared. The measured catalyst activity demonstrates that in spite of major support surface area loss in VTNT-5 catalyst, the propylene yield is superior in comparison with VTi5 catalyst. The catalyst activity can be correlated with maximum reduction temperature. Deactivation of VTi5 and VTNT-5 as well as VTNT-15 were studied for 3,000 min time-on-stream. It was found that the activity of VTNT-5 catalyst remain unchanged while a decline in catalytic activity observed in VTi5 and VTNT-15 catalysts. The development of rutile was considered as being a major element in the deactivation of the investigated catalysts which is influenced by the presence of vanadium and reaction atmosphere.

  19. X-Ray Absorption Spectroscopy of Mo and Ni K-edge of Supported Hydrotreating Catalysts

    Institute of Scientific and Technical Information of China (English)

    DuanAijun; XuChunming; ZhaoZhen; DongPeng

    2005-01-01

    X-ray absorption fine structure (XAFS) and other techniques have been used to characterize Ni-Mo/Al2O3 supported catalysts. The analysis of Mo K-edge spetrum shows that the active species over sulfide catalysts are MoS2-alike and the dispersion of Mo is high at the level of nanometer particles. There may exist some distortion of the local environment of MoS2, which has an influence on the hydrotreating activities of catalysts. Ni K-edge analysis shows that the coordination effects of Ni-Mo favor the dispersion state of active phase and imply a close relationship with catalyst activities.

  20. Biopolymer-supported ionic-liquid-phase ruthenium catalysts for olefin metathesis.

    Science.gov (United States)

    Clousier, Nathalie; Filippi, Alexandra; Borré, Etienne; Guibal, Eric; Crévisy, Christophe; Caijo, Fréderic; Mauduit, Marc; Dez, Isabelle; Gaumont, Annie-Claude

    2014-04-01

    Original ruthenium supported ionic liquid phase (SILP) catalysts based on alginates as supports were developed for olefin metathesis reactions. The marine biopolymer, which fulfills most of the requisite properties for a support such as widespread abundance, insolubility in the majority of organic solvents, a high affinity for ionic liquids, high chemical stability, biodegradability, low cost, and easy processing, was impregnated by [bmim][PF6 ] containing an ionically tagged ruthenium catalyst. These biosourced catalysts show promising performances in ring-closing metathesis (RCM) and cross-metathesis (CM) reactions, with a high level of recyclability and reusability combined with a good reactivity.

  1. Biopolymer-supported ionic-liquid-phase ruthenium catalysts for olefin metathesis.

    Science.gov (United States)

    Clousier, Nathalie; Filippi, Alexandra; Borré, Etienne; Guibal, Eric; Crévisy, Christophe; Caijo, Fréderic; Mauduit, Marc; Dez, Isabelle; Gaumont, Annie-Claude

    2014-04-01

    Original ruthenium supported ionic liquid phase (SILP) catalysts based on alginates as supports were developed for olefin metathesis reactions. The marine biopolymer, which fulfills most of the requisite properties for a support such as widespread abundance, insolubility in the majority of organic solvents, a high affinity for ionic liquids, high chemical stability, biodegradability, low cost, and easy processing, was impregnated by [bmim][PF6 ] containing an ionically tagged ruthenium catalyst. These biosourced catalysts show promising performances in ring-closing metathesis (RCM) and cross-metathesis (CM) reactions, with a high level of recyclability and reusability combined with a good reactivity. PMID:24616203

  2. Relationship between surface microstructure and properties of supported catalyst Rh/Ys

    Institute of Scientific and Technical Information of China (English)

    柳忠阳; 潘平来; 朱长城; 王晓筠; 袁国卿

    1997-01-01

    The inner structure of Rh/Ys,a novel high efficiency supported catalyst,and the spreading of Rh on the Ys surface were analyzed through electron transmission microscopy and scanning tunnel microscopy.The relationship between the distribution of Rh over the support and the preparation temperature of th catalyst was determined.The formation of Rh-C bond was confirmed by XPS and far-IR spectra.The loss of Rh from the surface of the support and the catalytic activity under different preparation conditions have been compared.The internal factors for the high activity and high stability of the novel Rh/Ys catalyst have been discussed.

  3. Stability and catalytic performance of vanadia supported on nanostructured titania catalyst in oxidative dehydrogenation of propane

    Science.gov (United States)

    Kootenaei, A. H. Shahbazi; Towfighi, J.; Khodadadi, A.; Mortazavi, Y.

    2014-04-01

    Titanate nanotubes with a high specific surface area were synthesized by the simple hydrothermal method and investigated as support for V2O5 catalyst in oxidative dehydrogenation of propane (ODP). The structures of pristine nanotubes as well as the prepared catalysts were investigated by XRD, Raman, FTIR, HRTEM, SEM, EDS, BET, and XPS techniques. The characterization of the as-synthesized nanotubes showed the synthesis of hydrogen titanate nanotube. The incipient wetness impregnation method was utilized to prepare VTNT-x (x = 5, 10, and 15 wt.% vanadia supported on nanotube) together with VTi5 (5 wt.% vanadia supported on Degussa P25). The anatase phase was developed in VTNT-x catalysts upon calcination along with specific surface area loss. Higher vanadia loading resulted in the lowering of support capacity in maintaining vanadia in dispersed state such that eventually crystalline vanadia appeared. The measured catalyst activity demonstrates that in spite of major support surface area loss in VTNT-5 catalyst, the propylene yield is superior in comparison with VTi5 catalyst. The catalyst activity can be correlated with maximum reduction temperature. Deactivation of VTi5 and VTNT-5 as well as VTNT-15 were studied for 3,000 min time-on-stream. It was found that the activity of VTNT-5 catalyst remain unchanged while a decline in catalytic activity observed in VTi5 and VTNT-15 catalysts. The development of rutile was considered as being a major element in the deactivation of the investigated catalysts which is influenced by the presence of vanadium and reaction atmosphere.

  4. Oxidative desulfurization of synthetic diesel using supported catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Cedeno Caero, Luis; Jorge, F.; Navarro, A.; Gutierrez-Alejandre, Aida [UNICAT, Depto. de Ing. Quimica, Facultad de Quimica, Universidad Nacional Autonoma de Mexico, Cd. Universitaria, 04510 Mexico D.F. (Mexico)

    2006-09-15

    Oxidative desulfurization (ODS) of a synthetic diesel was carried out at mild conditions (atmospheric pressure and 60{sup o}C) in presence of V{sub 2}O{sub 5}/Al{sub 2}O{sub 3} and V{sub 2}O{sub 5}/TiO{sub 2} catalysts. Two main aspects were studied: the effect of the oxidant reagent and the presence of nitrogen compounds on ODS of benzothiophenic compounds prevailing in diesel, such as benzothiophene, dibenzothiophene and alkyl substituted in positions 4 and 6. Results show that activity is improved when using hydrogen peroxide, as oxidant reagent, and V{sub 2}O{sub 5}/Al{sub 2}O{sub 3}, as catalyst. This result was attributed to the high decomposition of peroxide due to the presence of catalyst. In presence of nitrogen compounds, the ODS activity decreases in the order: quinoline>indole>carbazole. In order to explain this effect, successive chemisorption of DBT and quinoline on V{sub 2}O{sub 5}/Al{sub 2}O{sub 3} catalyst was evaluated by FT-IR, and the results show that DBT is displaced by quinoline, occupying the adsorption sites of catalyst. N-compound effect could be explained by strong adsorption of nitrogen compounds on catalytic sites. (author)

  5. Catalytic wet air oxidation of chlorophenols over supported ruthenium catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Li Ning [Institut de recherches sur la catalyse et l' environnement de Lyon (IRCELYON), UMR 5256, CNRS/Universite Claude Bernard Lyon 1, 2 Avenue Albert Einstein, 69626 Villeurbanne Cedex (France); Descorme, Claude [Institut de recherches sur la catalyse et l' environnement de Lyon (IRCELYON), UMR 5256, CNRS/Universite Claude Bernard Lyon 1, 2 Avenue Albert Einstein, 69626 Villeurbanne Cedex (France)]. E-mail: claude.descorme@catalyse.cnrs.fr; Besson, Michele [Institut de recherches sur la catalyse et l' environnement de Lyon (IRCELYON), UMR 5256, CNRS/Universite Claude Bernard Lyon 1, 2 Avenue Albert Einstein, 69626 Villeurbanne Cedex (France)

    2007-07-31

    A series of noble metal (Pt, Pd, Ru) loaded zirconia catalysts were evaluated in the catalytic wet air oxidation (CWAO) of mono-chlorophenols (2-CP, 3-CP, 4-CP) under relatively mild reaction conditions. Among the investigated noble metals, Ru appeared to be the best to promote the CWAO of CPs as far as incipient-wetness impregnation was used to prepare all the catalysts. The position of the chlorine substitution on the aromatic ring was also shown to have a significant effect on the CP reactivity in the CWAO over 3 wt.% Ru/ZrO{sub 2}. 2-CP was relatively easier to degradate compared to 3-CP and 4-CP. One reason could be the higher adsorption of 2-CP on the catalyst surface. Further investigations suggested that 3 wt.% Ru/ZrO{sub 2} is a very efficient catalyst in the CWAO of 2-CP as far as high 2-CP conversion and TOC abatement could still be reached at even lower temperature (393 K) and lower total pressure (3 MPa). Additionally, the conversion of 2-CP was demonstrated to increase with the initial pH of the 2-CP solution. The dechlorination reaction is promoted at higher pH. In all cases, the adsorption of the reactants and the reaction intermediates was shown to play a major role. All parameters that would control the molecule speciation in solution or the catalyst surface properties would have a key effect.

  6. A New Model Describing the Metal-Support Interaction in Noble Metal Catalysts

    NARCIS (Netherlands)

    Koningsberger, D.C.; Mojet, B.L.; Miller, J.T.; Ramaker, D.E.

    1999-01-01

    The catalytic activity and spectroscopic properties of supported noble metal catalysts are strongly influenced by the acidity/alkalinity of the support but are relatively independent of the metal (Pd or Pt) or the type of support (zeolite LTL or SiO{2}). As the alkalinity of the support increases, t

  7. Low-temperature SCR of NOx with NH3 over carbon-ceramic supported catalysts

    International Nuclear Information System (INIS)

    A new method for preparing vanadium oxide supported on carbon-ceramic cellular monoliths is described. This includes a support oxidation step with HNO3, followed by ionic exchange with a NaOH solution, equilibrium adsorption impregnation of VO2+ and thermal treatment. As a result an active catalyst for low-temperature selective catalytic reduction (SCR) reaction is obtained. The V-catalyst is more resistant to SO2 poisoning than the previously developed Mn-catalyst. Inhibition by water is reversible for both types of catalysts. Testing of the vanadium catalyst after subjecting it to the outlet gas stream of a power plant shows fast deactivation until constant residual activity is reached. Deactivation seems to be caused by arsenic poisoning and the formation of superficial sulphates

  8. Gaseous exchange reaction of deuterium between hydrogen and water on hydrophobic catalyst supporting platinum

    International Nuclear Information System (INIS)

    The deuterium exchange reaction between hydrogen and water in the gas phase where the fed hydrogen gas is saturated with water vapor is studied experimentally by use of the proper hydrophobic catalysts supporting platinum. It is found that the activities of those catalysts for this reaction system are very high compared with the other known ones for the systems in which gas and liquid should coexist on catalyst surfaces, and that the apparent catalytic activity becomes larger as the amount of platinum supported on a catalyst particle increases. By analyses of the data the following informations are obtained. The exchange reaction can be expressed by a first order reversible reaction kinetics. The pore diffusion in the catalyst particles has significant effect on the overall reaction mechanisms. (author)

  9. Particle size effects in Fischer-Tropsch synthesis by Co catalyst supported on carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    Ali Nakhaei Pour; Elham Hosaini; Mohammad Izadyar; Mohammad Reza Housaindokht

    2015-01-01

    The effect of Co particle size on the Fischer-Tropsch synthesis (FTS) activity of carbon nanotube (CNT)-supported Co catalysts was investigated. Microemulsion (using water-to-surfactant molar ratios of 2 to12) and impregnation techniques were used to prepare catalysts with different Co particle sizes. Kinetic studies were performed to understand the effect of Co particle size on catalytic activity. Size-dependent kinetic parameters were developed using a thermodynamic method, to evaluate the structural sensitivity of the CNT-supported Co catalysts. The size-independent FTS reaction rate constant and size-independent adsorption parameter increased with increasing reac-tion temperature. The Polani parameter also depended on catalyst particle size, because of changes in the catalyst surface coverage.

  10. Hydrotalcite-supported Pd-Cu catalyst for nitrate adsorption and reduction from water

    Institute of Scientific and Technical Information of China (English)

    WANG Ying; QU Jiuhui; LIU Huijuan; WU Rongcheng

    2006-01-01

    Hydrotalcite-supported Pd-Cu catalyst for nitrate adsorption and catalytic reduction from water is prepared by co-impregnation method and characterized by surface area (BET), X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and X-ray photoelectron spectrum (XPS). The performance of adsorption and hydrogenation of nitrate was evaluated and compared with Al2O3, TiO2, and HZSM-supported Pd-Cu catalysts. The experimental results demonstrated that hydrotalcite-supported Pd-Cu catalyst exhibited a high surface area (185.3 m2/g) and mesopore structure (average pore diameter of 52.2 (A)). The active metal clusters were homogeneously dispersed on the support, and the size of the most was less than 10 nm. Excellent adsorption for nitrate resulted from that nitrate ions were forced to enter the interlayer space when the calcined hydrotalcite regenerated layer structure in nitrate solution. The adsorption isotherm could be well described by the Langmuir model. The comparison between the adsorption and catalytic hydrogenation for nitrate using hydrogen indicated that nitrate reduction on hydrotalcite-supported Pd-Cu catalysts was a consecutive and dynamic adsorption and catalytic hydrogenation process. Compared with the Al2O3, TiO2, and HZSM- supported catalysts, hydrotalcite-supported Pd-Cu catalyst possessed higher catalytic activity and selectivity. The analysis on the dissolving of metals in the solution demonstrated that there was hydrolyzation on the surface of the hydrotalcite-supported Pd-Cu catalyst. However, the concentrations of dissolved metals in the solution were lower than the standard executed in China. The activity of the hydrotalcite-supported Pd-Cu catalyst for nitrate reduction kept steady after repeated use.

  11. Chemical and electrochemical promotion of supported rhodium catalyst

    OpenAIRE

    Baranova, Olena; Comninellis, Christos

    2007-01-01

    The chemical and electrochemical promotion of highly dispersed nanofilm Rh catalysts (dispersion: about 10 %, film thickness: 40 nm) has been investigated for the first time. To this end Rh metal was sputter-deposited, either on a purely ionic conductor (8 % Y2O3-stabilized ZrO2) or on a mixed ionic-electronic conductor (TiO2), the latter being a highly dispersed layer of TiO2 (4 µm) deposited on YSZ. These catalysts are designated as Rh/YSZ and Rh/TiO2/YSZ, respectively. It was established a...

  12. 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.

  13. Ruthenium carbonyl catalyst supported on ceric oxide for preparation of olefins from synthesis gas

    Science.gov (United States)

    Pierantozzi, Ronald

    1985-01-01

    A catalyst comprising a ruthenium carbonyl compound deposited on a cerium oxide-containing support material provides for the selective synthesis of low molecular weight olefinic hydrocarbons from mixtures of hydrogen and carbon monoxide.

  14. Supported ZnO catalysts for the conversion of alkanes: About the metamorphosis of a heterogeneous catalyst

    Institute of Scientific and Technical Information of China (English)

    S.Arndt; B.Uysal; A.Berthold; T.Otrebma; Y.Aksu; M.Driess; R.Schom(a)cker

    2012-01-01

    ZnO could be a suitable catalyst for the oxidative conversion of CH4,C2H6 and C3H8.However,the main drawback is its thermal instability.Therefore,ZnO supported on ZrO2,TiO2,γ-Al2O3 and SiO2 was investigated for the oxidative dehydrogenation of propane,and ethane,and the oxidative coupling of methane.The stability of the supported ZnO is partially improved,but ZnO reacts with the support material,forming new compounds (Zn-zirconates,-titanates,-aluminates and-silicates),which already occurs below reaction temperature.This might also be the case for many other heterogeneous catalysts.

  15. Steam Reforming of Ethylene Glycol over MgAl₂O₄ Supported Rh, Ni, and Co Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Mei, Donghai; Lebarbier, Vanessa M.; Xing, Rong; Albrecht, Karl O.; Dagle, Robert A.

    2015-11-25

    Steam reforming of ethylene glycol (EG) over MgAl₂O₄ supported metal (15 wt.% Ni, 5 wt.% Rh, and 15 wt.% Co) catalysts were investigated using combined experimental and theoretical methods. Compared to highly active Rh and Ni catalysts with 100% conversion, the steam reforming activity of EG over the Co catalyst is comparatively lower with only 42% conversion under the same reaction conditions (500°C, 1 atm, 119,000 h⁻¹, S/C=3.3 mol). However, CH₄ selectivity over the Co catalyst is remarkably lower. For example, by varying the gas hour space velocity (GHSV) such that complete conversion is achieved for all the catalysts, CH₄ selectivity for the Co catalyst is only 8%, which is much lower than the equilibrium CH₄ selectivity of ~ 24% obtained for both the Rh and Ni catalysts. Further studies show that varying H₂O concentration over the Co catalyst has a negligible effect on activity, thus indicating zero-order dependence on H₂O. These experimental results suggest that the supported Co catalyst is a promising EG steam reforming catalyst for high hydrogen production. To gain mechanistic insight for rationalizing the lower CH₃ selectivity observed for the Co catalyst, the initial decomposition reaction steps of ethylene glycol via C-O, O-H, C-H, and C-C bond scissions on the Rh(111), Ni(111) and Co(0001) surfaces were investigated using density functional theory (DFT) calculations. Despite the fact that the bond scission sequence in the EG decomposition on the three metal surfaces varies, which leads to different reaction intermediates, the lower CH₄ selectivity over the Co catalyst, as compared to the Rh and Ni catalysts, is primarily due to the higher barrier for CH₄ formation. The higher S/C ratio enhances the Co catalyst stability, which can be elucidated by the facile water dissociation and an alternative reaction path to remove the CH species as a coking precursor via the HCOH formation. This work was financially supported by the United

  16. Towards stable catalysts by controlling collective properties of supported metal nanoparticles

    Science.gov (United States)

    Prieto, Gonzalo; Zečević, Jovana; Friedrich, Heiner; de Jong, Krijn P.; de Jongh, Petra E.

    2013-01-01

    Supported metal nanoparticles play a pivotal role in areas such as nanoelectronics, energy storage/conversion and as catalysts for the sustainable production of fuels and chemicals. However, the tendency of nanoparticles to grow into larger crystallites is an impediment for stable performance. Exemplarily, loss of active surface area by metal particle growth is a major cause of deactivation for supported catalysts. In specific cases particle growth might be mitigated by tuning the properties of individual nanoparticles, such as size, composition and interaction with the support. Here we present an alternative strategy based on control over collective properties, revealing the pronounced impact of the three-dimensional nanospatial distribution of metal particles on catalyst stability. We employ silica-supported copper nanoparticles as catalysts for methanol synthesis as a showcase. Achieving near-maximum interparticle spacings, as accessed quantitatively by electron tomography, slows down deactivation up to an order of magnitude compared with a catalyst with a non-uniform nanoparticle distribution, or a reference Cu/ZnO/Al2O3 catalyst. Our approach paves the way towards the rational design of practically relevant catalysts and other nanomaterials with enhanced stability and functionality, for applications such as sensors, gas storage, batteries and solar fuel production.

  17. Characterization of Al2O3 Supported Nickel Catalysts Derived from RFNon-thermal Plasma Technology

    International Nuclear Information System (INIS)

    Catalysts derived from non-thermal plasma techniques have previously shown unusual and highly advantageous catalytic properties including room temperature reduction, unusual metal particle structure and metal-support interactions, and enhanced selectivity and stability. This study focuses on the characterization of Al2O3 supported Ni catalysts derived from the RF non-thermal plasma technique with in-situ XRD, TPR-MS and STEM and on relating the results to the enhanced activity and stability of benzene hydrogenation. The results suggest that catalysts with plasma treatments before impregnation are relatively easier to be reduced and result in better activities under mild reduction conditions. These plasma treatments stabilize the nickel particle sizes of air(B) and H2(B) catalysts at 600 C by slowing down the sintering process. Plasma treatments after the impregnation of precursors, on the other hand, tend to delay the growth of nickel particles below 600 C, forming smaller Ni particles, but with a sudden increase in particle size near 600 C. It suggests that the structure of Ni nitrate and the metal-support interaction have been altered by the plasma treatments. The reduction patterns of plasma 1 treated catalysts are, therefore, changed. The catalyst with a combination plasma treatment demonstrates that the effect of a combination plasma treatment is larger than either the plasma treatment before or after the impregnation alone. Both plasma treatments before and after the impregnation of metal precursor play important roles in modifying supported metal catalysts.

  18. Allotropic Carbon Nanoforms as Advanced Metal-Free Catalysts or as Supports

    Directory of Open Access Journals (Sweden)

    Hermenegildo Garcia

    2014-01-01

    Full Text Available This perspective paper summarizes the use of three nanostructured carbon allotropes as metal-free catalysts (“carbocatalysts” or as supports of metal nanoparticles. After an introductory section commenting the interest of developing metal-free catalysts and main features of carbon nanoforms, the main body of this paper is focused on exemplifying the opportunities that carbon nanotubes, graphene, and diamond nanoparticles offer to develop advanced catalysts having active sites based on carbon in the absence of transition metals or as large area supports with special morphology and unique properties. The final section provides my personal view on future developments in this field.

  19. 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 ......H of the impregnation solution and of the reduction temperature of the precursor salts resulted in a very active catalyst with average particle size of 1.7 nm. (c) 2006 Elsevier B.V. All rights reserved....

  20. 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

    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......, 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...

  1. 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...... preparation parameters were examined, including the choice of precipitant, variation of carrier surface area, potassium poisoning, crystallinity, and ZrO2-phase composition. The results show that the catalysts structure and SCR activity is affected from the synthesis route by means of support crystallinity...

  2. Dehydration of Glycerin to Acrolein Over Heteropolyacid Nano-Catalysts Supported on Silica-Alumina.

    Science.gov (United States)

    Kang, Tae Hun; Choi, Jung Ho; Choi, Jun Seon; Song, In Kyu

    2015-10-01

    A series of H3PW12O40 nano-catalysts supported on silica-alumina (XH3PW12O40/SA (X = 10, 15, 20, 25, and 30)) with different H3PW12O40 content (X, wt%) were prepared, and they were applied to the dehydration of glycerin to acrolein. The effect of H3PW12O40 content on the physicochemical properties and catalytic activities of XH3PW12O40/SA nano-catalysts was investigated. Surface area and pore volume of XH3PW12O40/SA catalysts decreased with increasing H3PW12O40 content. Formation of H3PW12O40 aggregates was observed in the catalysts with high H3PW12O40 loading. Brønsted acidity of the catalysts showed a volcano-shaped trend with respect to H3PW12O40 content. It was revealed that yield for acrolein increased with increasing Brønsted acidity of XH3PW12O40/SA catalysts. Brønsted acidity of XH3PW12O40/SA catalysts served as a crucial factor determining the catalytic performance in the dehydration of glycerin. Among the catalysts tested, 25H3PW12O40/SA catalyst with the largest Brønsted acidity showed the best catalytic performance.

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

    Science.gov (United States)

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

    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.

  4. 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...

  5. ASYMMETRIC HYDROSILYLATION CATALYZED BY POLYMER—SUPPORTED THIAZOLIDINE RHODIUM CATALYSTS

    Institute of Scientific and Technical Information of China (English)

    LEIYanohui; LIHong; 等

    1999-01-01

    Asymmetric hydrisilylation catalyzed by polymeric thiazolidine rhodium catalysts was conducted.Almost the same optical yields have been obtained when comb-shaped polymeric ligands and their corresponding monomer complexed rhodium cataltysts were used to asymmetric hydrosilylation of acetophenone.Optical yield of chiral 1-methylbenzyl alcohol reaches as high as 71.5%.Temperature dependence of enantioselective hydrosilylation of acetophenone was discussed.

  6. 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.

  7. LDRD final report on new homogeneous and supported oligomerization catalysts (LDRD 42461).

    Energy Technology Data Exchange (ETDEWEB)

    Hascall, Anthony G.; Kemp, Richard Alan

    2004-11-01

    The overall purpose of this LDRD is multifold. First, we are interested in preparing new homogeneous catalysts that can be used in the oligomerization of ethylene and in understanding commercially important systems better. Second, we are interested in attempting to support these new homogeneous catalysts in the pores of nano- or mesoporous materials in order to force new and unusual distributions of a-olefins to be formed during the oligomerization. Thus the overall purpose is to try to prepare new catalytic species and to possibly control the active site architecture in order to yield certain desired products during a catalytic reaction, much like nature does with enzymes. In order to rationally synthesize catalysts it is imperative to comprehend the function of the various components of the catalyst. In heterogeneous systems, it is of utmost importance to know how a support interacts with the active site of the catalyst. In fact, in the catalysis world this lack of fundamental understanding of the relationship between active site and support is the single largest reason catalysis is considered an 'empirical' or 'black box' science rather than a well-understood one. In this work we will be preparing novel ethylene oligomerization catalysts, which are normally P-O chelated homogeneous complexes, with new ligands that replace P with a stable carbene. We will also examine a commercially catalyst system and investigate the active site in it via X-ray crystallography. We will also attempt to support these materials inside the pores of nano- and mesoporous materials. Essentially, we will be tailoring the size and scale of the catalyst active site and its surrounding environment to match the size of the molecular product(s) we wish to make. The overall purpose of the study will be to prepare new homogeneous catalysts, and if successful in supporting them to examine the effects that steric constraints and pore structures can have on growing oligomer

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

    Science.gov (United States)

    Wu, Ke; Zheng, Mengjia; Han, Yuxiang; Xu, Zhaoyi; Zheng, Shourong

    2016-07-01

    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 TiO2, CeO2, Al2O3 and SiO2 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 N2 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/TiO2 was much smaller than those in im-Pd/TiO2 and pd-Pd/TiO2. Pd particle size of the dp-Pd/TiO2 catalyst increased with Pd loading amount. Additionally, Pd particles in the dp-Pd/TiO2 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 loading amount, the Pd catalyst supported on TiO2 exhibited a much higher catalytic activity than those on other supports. Furthermore, dp-Pd/TiO2 was found to be more active than im-Pd/TiO2 and pd-Pd/TiO2.

  9. Recent development of supported monometallic gold as heterogeneous catalyst for selective liquid phase hydrogenation reactions

    Institute of Scientific and Technical Information of China (English)

    Thushara Kandaramath Hari; Zahira Yaakob

    2015-01-01

    The great potential of gold catalysts for chemical conversions in both industrial and environmental concerns has attracted increasing interest in many fields of research. Gold nanoparticles supported by metal oxides with high surface area have been recognized as highly efficient and effective green heterogeneous catalyst even at room temperature under normal reaction conditions, in gas and liquid phase reactions. In the present review, we dis-cuss the recent development of heterogeneous, supported monometal ic gold catalysts for organic transforma-tions emphasizing mainly liquid phase hydrogenation reactions. Discussions on the catalytic synthesis procedures and the promoting effect of other noble metals are omitted since they are already worked out. Appli-cations of heterogeneous, supported monometal ic catalysts for chemoselective hydrogenations in liquid phase are studied including potential articles during the period 2000–2013.

  10. Synthesis of Gold Catalysts Supported on Mesoporous Silica Materials: Recent Developments

    Directory of Open Access Journals (Sweden)

    Khaled Belkacemi

    2011-12-01

    Full Text Available Mesoporous silica materials (MSM with ordered and controllable porous structure, high surface area, pore volume and thermal stability are very suitable catalyst supports, because they provide high dispersion of metal nanoparticles and facilitate the access of the substrates to the active sites. Since the conventional wet-impregnation and deposition-precipitation methods are not appropriate for the incorporation of gold nanoparticles (AuNPs into MSM, considerable efforts have been made to develop suitable methods to synthesize Au/MSM catalysts, because the incorporation of AuNPs into the channel system can prevent their agglomeration and leaching. In this review, we summarize the main methods to synthesize active gold catalysts supported on MSM. Examples and details of the preparative methods, as well as selected applications are provided. We expect this article to be interesting to researchers due to the wide variety of chemical reactions that can be catalyzed by gold supported catalysts.

  11. High-performance PdRu bimetallic catalyst supported on mesoporous silica nanoparticles for phenol hydrogenation

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Chao [The Key Laboratory of Fuel Cell Technology of Guangdong Province and The Key Laboratory for New Energy of Guangdong Universities, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou (China); Yang, Xu [Key Laboratory of Renewable Energy, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou (China); Yang, Hui; Huang, Peiyan; Song, Huiyu [The Key Laboratory of Fuel Cell Technology of Guangdong Province and The Key Laboratory for New Energy of Guangdong Universities, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou (China); Liao, Shijun, E-mail: chsjliao@scut.edu.cn [The Key Laboratory of Fuel Cell Technology of Guangdong Province and The Key Laboratory for New Energy of Guangdong Universities, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou (China)

    2014-10-01

    Graphical abstract: The addition of Ru could significantly improve the performance of the mesoporous silica nanoparticles supported PdRu/MSN catalyst, which showed over 5 times higher mass activity than the mono-Pd/MSN towards the liquid-phase hydrogenation of phenol. The improved dispersion and the electronic interaction contributed to the enhanced catalytic activity for the catalyst towards phenol hydrogenation. - Highlights: • PdRu bimetal catalyst supported on mesoporous silica nanoparticles was prepared. • The average sizeof PdRu alloy is smaller than that of mono-Pd. • The addition of Ru to Pd modulates the electronic properties between Pd and Ru. • PdRu/MSN catalyst shows superior activity on phenol hydrogenation than Pd/MSN. • PdRu/MSN catalyst shows good selectivity for cyclohexanol to some extent. - Abstract: A high-performance PdRu bimetallic catalyst supported on mesoporous silica nanoparticles (MSN), PdRu/MSN, was prepared by a facile impregnation–hydrogen reduction method. It was found that PdRu/MSN showed 5 times higher activity than that of Pd/MSN towards the liquid-phase hydrogenation of phenol. The catalysts were characterized comprehensively by multiple techniques, X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and hydrogen temperature program reduction (TPR). It was revealed that adding Ru could effectively improve the Pd dispersion and promote the electronic interaction between the Pd and Ru, both of which contribute to enhancing the catalytic activity.

  12. Nanoparticle-supported and magnetically recoverable palladium (Pd) catalyst: a selective and sustainable oxidation protocol with high turnover number

    Science.gov (United States)

    A magnetic nanoparticle-supported ruthenium hydroxide catalyst was readily prepared from inexpensive starting materials and shown to catalyze hydration of nitriles with excellent yield in benign aqueous medium. Catalyst recovery using an external magnetic field, superior activity...

  13. Polyethylene Glycol as Support and Phase Transfer Catalyst in Aqueous Palladium-catalyzed Liquid-phase Synthesis

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Excellent yields and purity were obtained in the aqueous medium Suzuki, Sonogashira, Stille and Heck reactions using palladium (Ⅱ) as catalyst in liquid phase synthesis. Polyethylene glycol (PEG) acted as soluble polymeric support and phase transfer catalyst as well.

  14. TiO2 nanotubes supported NiW hydrodesulphurization catalysts: Characterization and activity

    Science.gov (United States)

    Palcheva, R.; Dimitrov, L.; Tyuliev, G.; Spojakina, A.; Jiratova, K.

    2013-01-01

    High surface area TiO2 nanotubes (Ti-NT) synthesized by alkali hydrothermal method were used as a support for NiW hydrodesulphurization catalyst. Nickel salt of 12-tungstophosphoric acid - Ni3/2PW12O40 was applied as oxide precursor of the active components. The catalyst was characterized by SBET, XRD, UV-vis DRS, Raman spectroscopy, XPS, TPR and HRTEM. The results obtained were compared with those for the NiW catalysts prepared over high surface area titania and alumina supports. A polytungstate phase evidenced by Raman spectroscopy was observed indicating the destruction of the initial heteropolyanion. The catalytic experiments revealed two times higher thiophene conversion on NiW catalyst supported on Ti-NT than those of catalysts supported on alumina and titania. Increased HDS activity of the NiW catalyst supported on Ti-NT could be related to a higher amount of W oxysulfide entities interacting with Ni sulfide particles as consequence of the electronic effects of the Ti-NT observed with XPS analysis.

  15. MCM-41-supported cobalt-molybdenum catalysts for deep hydrodesulfurization of diesel and jet fuel feedstocks

    Science.gov (United States)

    Turaga, Uday Tsrpr

    Regulatory issues require new catalysts for the deep hydrodesulfurization (HDS) of refractory polyaromatic sulfur compounds such as 4,6-dimethyldibenzothiophene (4,6-DMDBT) present in diesel and jet fuel. Molybdenum sulfide (MoS2 ) supported on mesoporous molecular sieve MCM-41 and promoted by cobalt was hypothesized to have superior activity for deep HDS because of MCM-41's (1) high surface area and uniform mesopores and (2) superior acidity as compared to conventional supports such as gamma-alumina (gamma-Al 2O3). This study examines the role of MCM-41 as a support for new cobalt (Co)-molybdenum (Mo) HDS catalysts. At CoO-MoO3 loadings typical of commercially available HDS catalysts, MCM-41-supported catalysts were only slightly better. At higher loadings---27.0% (by weight) MoO3 and 5.8% CoO---MCM-41-supported catalysts were twice more active than the commercial catalyst. This difference in activities is related to the degree of MoS2 stacking. Remarkable increase in the conversion of 4,6-DMDBT was observed over MCM-41-supported catalysts with decreasing SiO2/Al2O 3 ratio. More significantly, the SiO2/Al2O 3 ratio of MCM-41 has a profound effect on product distribution and catalyst selectivity. Irrespective of CoO-MoO3 loading, catalysts using MCM-41 with a SiO2/Al2O3 ratio of 50 convert more of 4,6-DMDBT through the highly desirable hydrogenolysis pathway. The acidity of these catalysts was measured and correlated to their selectivities for hydrogenolysis and hydrocracking. Co-Mo/MCM-41 continued to demonstrate activities twice that of the commercial catalyst for the HDS of 4,6-DMDBT in petroleum-derived feedstocks such as light cycle oil. However, for a blend of coal- and petroleum-derived feedstocks, nitrogen from the coal-derived liquid inhibited both catalysts for the HDS of 4,6-DMDBT. Basic nitrogen, e.g., quinoline, significantly retards the HDS of 4,6-DMDBT over both catalysts. Non-basic carbazole, on the other hand, inhibited the MCM-41-supported

  16. Influence of Supports on Catalytic Performance and Carbon Deposition of Palladium Catalyst for Methane Partial Oxidation

    Institute of Scientific and Technical Information of China (English)

    Shi Fangli; Shen Meiqing; Fei Yanan; Wang Jun; Weng Duan

    2007-01-01

    The catalytic performance of methane partial oxidation was investigated on Pd/CeO2-ZrO2 and Pd/α-Al2O3 catalysts. The catalysts were characterized by XRD, Raman spectra, and TG-DTA techniques. The results show that CeO2-ZrO2 support is more advantageous for the catalytic activity and stability of catalysts compared to α-Al2O3. TG-DTA and Raman spectra results indicated that carbon deposited on the catalysts was in the form of graphite, which is the main reason for the deactivation of catalysts after a 24-hour reaction. Moreover, CeO2-ZrO2 had positive effect on inhibiting carbon deposition.

  17. Supported Molecular Catalysts: Synthesis, In-Situ Characterization and Performance

    Energy Technology Data Exchange (ETDEWEB)

    Davis, Mark E.

    2009-03-13

    The objectives of our work are: (i) to create solid catalysts with active sites that can function in a cooperative manner to enhance reactivity and selectivity, and (ii) to prepare solid catalysts that can perform multiple reactions in a network that in some cases would not be possible in solution due to the incompatibilities of the various catalytic entities (for example an acid and a base). We carried out extensive reactions to test the nature of the cooperative effect caused by thiol/sulfonic acid interactions. The acid/thiol combination provided an example where the two organic groups should be positioned as close to one another as possible. We also studied a system where this is not possible (acid-base). We investigated simultaneously incorporating acid and base groups into the same material. For the case of acid and bases, there is an optimal separation distance (too close allows for neutralization while too far eliminates any cooperative behavior).

  18. High CO methanation activity on zirconia-supported molybdenum sulfide catalyst

    Institute of Scientific and Technical Information of China (English)

    Zhenhua Li; Ye Tian; Jia He; Baowei Wang; Xinbin Ma

    2014-01-01

    In this study, different methods were used to prepare MoO3/ZrO2 catalysts for sulfur resistant methanation reaction. It was found that MoO3/ZrO2 catalyst prepared by one-step co-precipitation method achieved high methanation performance. CO conversion could reach up to 90%on 25 wt%MoO3/ZrO2 catalyst, much higher than that on the conventional 25 wt%MoO3/Al2O3 catalyst. The Mo-based catalysts were characterized by XRF, XRD, Raman, BET, TEM and H2-TPR etc. It was found that MoO3 particles were highly dispersed on ZrO2 support for 25 wt%MoO3/ZrO2 catalyst prepared at 65-85◦C because of its relatively larger pore size, which contributed to a high CO conversion. Meanwhile, when MoO3 loading exceeded the monolayer coverage, the formed crystalline MoO3 and ZrMo2 O8 might block the micropores of the catalyst and make the methanation activity declined. These results are useful for preparing highly efficient catalyst for CO methanation process.

  19. 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.

  20. Study of Supported Nickel Catalysts Prepared by Aqueous Hydrazine Method. Hydrogenating Properties and Hydrogen Storage: Support Effect. Silver Additive Effect

    International Nuclear Information System (INIS)

    We have studied Ni or NiAg nano-particles obtained by the reduction of nickel salts (acetate or nitrate) by hydrazine and deposited by simple or EDTA-double impregnation on various supports (γ-Al2O3, amorphous or crystallized SiO2, Nb2O5, CeO2 and carbon). Prepared catalysts were characterized by different methods (XRD, XPS, low temperature adsorption and desorption of N2, FTIR and FTIR-Pyridine, TEM, STEM, EDS, H2-TPR, H2-adsorption, H2-TPD, isopropanol decomposition) and tested in the gas phase hydrogenation of benzene or as carbon materials in the hydrogen storage at room temperature and high pressure. The catalysts prepared exhibited better dispersion and activity than classical catalysts. TOF's of NiAg/SiO2 or Ni/carbon catalysts were similar to Pt catalysts in benzene hydrogenation. Differences in support acidity or preparation method and presence of Ag as metal additive play a crucial role in the chemical reduction of Ni by hydrazine and in the final properties of the materials. Ni/carbon catalysts could store significant amounts of hydrogen at room temperature and high pressure (0.53%/30 bars), probably through the hydrogen spillover effect. (author)

  1. 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.

  2. Role of vanadium in Keggin heteropoly molybdate supported on titania catalysts for oxidation reactions

    Indian Academy of Sciences (India)

    A Srivani; K T Venkateswara Rao; P S Sai Prasad; N Lingaiah

    2014-03-01

    Vanadium-incorporated molybdophosporic acid catalysts supported on titania were prepared and characterized by FT-IR, X-ray diffraction and laser Raman spectroscopy. Characterization data reveals the incorporation of vanadium into the primary structure of Keggin ion of MPA. Catalysts activities were evaluated for oxidation of 1,2-benzenedimethanol using H2O2 and O2 as oxidants. Vanadium-containing catalysts showed high activity compared to their parent heteropoly acids. Oxidation ability depended on the number of V atoms present in Keggin heteropoly molybdate. Effect of reaction parameters on the oxidation ability was also evaluated.

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

    OpenAIRE

    2008-01-01

    Ni/SiO2 and Ni/Mg(Al)O catalysts with difference metal loadings have been prepared. The activity, selectivity and stability of supported Ni catalysts for propane dry reforming to syngas reaction were investigated by catalytic testing at 600 ºC, C3H8:CO2:H2:N2 (in vol.%) = 10:30:10:50. Ni particle size was investigated by Transmission electron microscopy (TEM). Turn-over frequencies for Ni/SiO2 catalysts were calculated as a guideline to the relationship between catalytic activity and Ni parti...

  4. Highly selective oxidative dehydrogenation of ethane with supported molten chloride catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Gaertner, C.A.; Veen, A.C. van; Lercher, J.A. [Technische Univ. Muenchen (Germany). Catalysis Research Center

    2011-07-01

    Ethene production is one of the most important transformations in chemical industry, given that C{sub 2}H{sub 4} serves as building block for many mass-market products. Besides conventional thermal processes like steam cracking of ethane, ethane can be produced selectively by catalytic processes. One of the classes of catalysts that have been reported in literature as active and highly selective for the oxidative dehydrogenation of ethane is that of supported molten chloride catalysts, containing an alkali chloride overlayer on a solid support. This work deals with fundamental aspects of the catalytic action in latter class of catalysts. Results from kinetic reaction studies are related to observations in detailed characterization and lead to a comprehensive mechanistic understanding. Of fundamental importance towards mechanistic insights is the oxygen storage capacity of the catalysts that has been determined by transient step experiments. (orig.)

  5. Selective liquid phase oxidation of glycerol to glyceric acid over novel supported Pt catalysts

    Directory of Open Access Journals (Sweden)

    Sproge Elina

    2013-01-01

    Full Text Available Several supported platinum catalysts were prepared by extractive-pyrolytic method for the selective glyceric acid production from glycerol. Al2O3, Y2O3, Lu2O3, ZrO2-Y2O3 TiO2, SG, Fe2O3, γ-AlO(OH and C were used as catalyst supports, glycerol oxidation was carried out in the alkaline solutions and oxygen was used as oxidant. The optimal catalyst preparation parameters and glycerol oxidation conditions to obtain glyceric acid were determined. The best result (selectivity to glyceric acid 57% with glycerol conversion 92% was achieved in the presence of 4.8%Pt/Al2O3 catalyst.

  6. Supported ruthenium-carbene catalyst on ionic magnetic nanoparticles for olefin metathesis.

    Science.gov (United States)

    Chen, Shu-Wei; Zhang, Zhi-Cheng; Ma, Miaofeng; Zhong, Chong-Min; Lee, Sang-gi

    2014-10-01

    The Grubbs-Hoveyda ruthenium-carbene complex has been covalently immobilized on ionic magnetic nanoparticles utilizing an imidazolium salt linker. The supported catalyst exhibited excellent catalytic activity for ring-closing metathesis (RCM) and cross-metathesis (CM) in the presence of less than 1 mol % of ruthenium. The catalysts can easily be recovered magnetically and reused up to seven times with minimal leaching of ruthenium species.

  7. Supported ruthenium-carbene catalyst on ionic magnetic nanoparticles for olefin metathesis.

    Science.gov (United States)

    Chen, Shu-Wei; Zhang, Zhi-Cheng; Ma, Miaofeng; Zhong, Chong-Min; Lee, Sang-gi

    2014-10-01

    The Grubbs-Hoveyda ruthenium-carbene complex has been covalently immobilized on ionic magnetic nanoparticles utilizing an imidazolium salt linker. The supported catalyst exhibited excellent catalytic activity for ring-closing metathesis (RCM) and cross-metathesis (CM) in the presence of less than 1 mol % of ruthenium. The catalysts can easily be recovered magnetically and reused up to seven times with minimal leaching of ruthenium species. PMID:25215600

  8. Study on the Reaction Mechanism for Carbon Dioxide Reforming of Methane over supported Nickel Catalyst

    Institute of Scientific and Technical Information of China (English)

    Ling QIAN; Zi Feng YAN

    2003-01-01

    The adsorption and dissociation of methane and carbon dioxide for reforming on nickelcatalyst were extensively investigated by TPSR and TPD experiments. It showed that thedecomposition of methane results in the formation of at least three kinds of surface carbon specieson supported nickel catalyst, while CO2 adsorbed on the catalyst weakly and only existed in onekind of adsorption state. Then the mechanism of interaction between the species dissociatedfrom CH4 and CO2 during reforming was proposed.

  9. TiO{sub 2} nanotubes supported NiW hydrodesulphurization catalysts: Characterization and activity

    Energy Technology Data Exchange (ETDEWEB)

    Palcheva, R., E-mail: palcheva@gmail.com [Institute of Catalysis, Bulgarian Academy of Sciences, G. Bonchev Str., Bldg. 11, 1113 Sofia (Bulgaria); Dimitrov, L. [Institute of Mineralogy and Crystallography Acad. I. Kostov, G. Bonchev Str., Bldg. 107, 1113 Sofia (Bulgaria); Tyuliev, G.; Spojakina, A. [Institute of Catalysis, Bulgarian Academy of Sciences, G. Bonchev Str., Bldg. 11, 1113 Sofia (Bulgaria); Jiratova, K. [Institute of Chemical Process Fundamentals, Academy of Sciences of the Czech Republic, 165 02 Prague 6 (Czech Republic)

    2013-01-15

    Highlights: Black-Right-Pointing-Pointer NiW catalysts supported on TiO{sub 2} nanotubes, titania and alumina. Black-Right-Pointing-Pointer The best results are obtained with NiW/TiO{sub 2} nanotubes in hydrodesulfurization (HDS) of thiophene. Black-Right-Pointing-Pointer Active phase is Ni-WO{sub x}S{sub y}. Black-Right-Pointing-Pointer Electronic promotion of W by Ti. - Abstract: High surface area TiO{sub 2} nanotubes (Ti-NT) synthesized by alkali hydrothermal method were used as a support for NiW hydrodesulphurization catalyst. Nickel salt of 12-tungstophosphoric acid - Ni{sub 3/2}PW{sub 12}O{sub 40} was applied as oxide precursor of the active components. The catalyst was characterized by S{sub BET}, XRD, UV-vis DRS, Raman spectroscopy, XPS, TPR and HRTEM. The results obtained were compared with those for the NiW catalysts prepared over high surface area titania and alumina supports. A polytungstate phase evidenced by Raman spectroscopy was observed indicating the destruction of the initial heteropolyanion. The catalytic experiments revealed two times higher thiophene conversion on NiW catalyst supported on Ti-NT than those of catalysts supported on alumina and titania. Increased HDS activity of the NiW catalyst supported on Ti-NT could be related to a higher amount of W oxysulfide entities interacting with Ni sulfide particles as consequence of the electronic effects of the Ti-NT observed with XPS analysis.

  10. Catalytic cracking process exploying a zeolite as catalysts and catalyst supports

    Energy Technology Data Exchange (ETDEWEB)

    Lussier, R.J.; Surland, G.J.

    1989-06-06

    This patent describes a method for cracking hydrocarbons which comprises reacting a hydrocarbon feedstock under catalytic cracking conditions in the presence of a cracking catalyst composition which comprises a crystalline zeolite, an inorganic oxide matrix, and a finely divided, calcined caustic leached aluminum silicon spinel/mullite component having a silica to alumina mole ratio of from about 0.5 to 1.7 and an acid site retention of from about 70 to 95 percent after treating at 1350{sup 0}F in the presence of saturated steam and a X-ray diffraction pattern as set forth in Tables A or B.

  11. Not only V(V) - What really is the nature of supported vanadate catalysts?

    OpenAIRE

    Klose, F.; Wolff, T; Lorenz, H.; Seidel-Morgenstern, A.; Suchorski, Y.; Piorkowska, M.; H. Weiss

    2007-01-01

    Supported vanadia catalysts are important catalysts for oxidation reactions. Depending on the kind of support and on the doping degree, vanadia is either spread over the sup-ports surface forming thin layers of vanadates or it agglomerates at higher loadings yielding V2O5 crystallites. Commonly, vanadates are proposed to consist of VO4 units, in which mono- and polyvanadates are distinguished (e.g. [1-3]). In this concept, in the oxidized state all V atoms are assumed to be in the oxidation s...

  12. Nanocrystalline MgO supported nickel-based bimetallic catalysts for carbon dioxide reforming of methane

    Energy Technology Data Exchange (ETDEWEB)

    Meshkani, Fereshteh [Catalyst and Advanced Materials Research Laboratory, Chemical Engineering Department, Faculty of Engineering, University of Kashan, Kashan (Iran); Rezaei, Mehran [Catalyst and Advanced Materials Research Laboratory, Chemical Engineering Department, Faculty of Engineering, University of Kashan, Kashan (Iran); Institute of Nanoscience and Nanotechnology, University of Kashan, Kashan (Iran)

    2010-10-15

    Nanocrystalline magnesium oxide with high surface area and plate-like shape was employed as catalyst support for preparation of nickel-based bimetallic catalysts in methane reforming with carbon dioxide. The prepared samples were characterized by X-ray diffraction (XRD), N{sub 2} adsorption (BET), Temperature programmed oxidation and desorption (TPO-TPD), Thermal gravimetric and differential thermal gravimetric (TGA-DTG), H{sub 2} chemisorption and Transmission and electron microscopies (TEM and SEM) analyses. CO{sub 2}-TPD data showed the high CO{sub 2} adsorption capacity of catalysts which improves the resistance of catalysts against the carbon formation. The H{sub 2} chemisorption results also indicated that the addition of Pt to nickel catalyst improved the nickel dispersion. The obtained results revealed that the prepared catalysts showed a high activity and stability during the reaction with a low amount of deposited carbon. Addition of Pt to nickel catalyst improved both the activity and resistivity against carbon formation. (author)

  13. 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.

  14. 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.

  15. 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.

  16. Characterization of vanadia catalysts on structured micro-fibrous glass supports for selective oxidation of hydrogen sulfide

    OpenAIRE

    Larina Tatyana V.; Cherepanova Svetlana V.; Rudina Nina A.; Kolesov Boris A.; Zagoruiko Andrey N.

    2016-01-01

    This work is focused on the characterization of a novel vanadium pentoxide catalysts on a glass-fiber support. The catalyst support consists of a non-porous glass-fiber fabric covered with an additional external surface layer of porous secondary support of SiO2. The vanadia active component is synthesized from vanadyl oxalate precursor by means of an impulse surface thermo-synthesis method. Such catalysts demonstrate high activity and appropriate selectivity in the rea...

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

    International Nuclear Information System (INIS)

    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

  18. 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.

  19. Vapor-phase Nitration of Benzene to Nitrobenzene over Supported Sulfuric Acid Catalyst

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Vapor-phase nitration of benzene over solid acid catalyst is expected to be a clean process with no sulfuric acid waste.We investigated this process over solid acidic catalysts utilizing diluted nitric acid (60-70%) as nitrating agent,and found that supported sulfuric acid catalyst exhibited a very high catalytic activity.Under the conditions of reaction temperature 160-170℃,space velocity (SV) 1200 h-1,the yield and the space-time yield (STY) of nitrobenzene (NB) based on HNO3 were more than 98% and 0.75 kg@kgcat-1@h-1 over 10% H2SO4/SiO2 (by weight) catalyst respectively.

  20. Physicochemical investigations of carbon nanofiber supported Cu/ZrO{sub 2} catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Din, Israf Ud, E-mail: drisraf@yahoo.com, E-mail: maizats@petronas.com.my; Shaharun, Maizatul S., E-mail: drisraf@yahoo.com, E-mail: maizats@petronas.com.my [Department of Fundamental and Applied Sciences, Universiti Teknologi PETRONAS (Malaysia); Subbarao, Duvvuri, E-mail: duvvuri-subbarao@petronas.com.my [Department of Chemical Engineering, Universiti Teknologi PETRONAS (Malaysia); Naeem, A., E-mail: naeeem64@yahoo.com [National Centre of Excellence in Physical Chemistry, University of Peshawar (Pakistan)

    2014-10-24

    Zirconia-promoted copper/carbon nanofiber catalysts (Cu‐ZrO{sub 2}/CNF) were prepared by the sequential deposition precipitation method. The Herringbone type of carbon nanofiber GNF-100 (Graphite nanofiber) was used as a catalyst support. Carbon nanofiber was oxidized to (CNF-O) with 5% and 65 % concentration of nitric acid (HNO{sub 3}). The CNF activated with 5% HNO{sub 3} produced higher surface area which is 155 m{sup 2}/g. The catalyst was characterized by X-ray Diffraction (XRD), Fourier Transform Infra-Red (FTIR) and N{sub 2} adsorption-desorption. The results showed that increase of HNO{sub 3} concentration reduced the surface area and porosity of the catalyst.

  1. 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.

  2. Electro-Deposition Pt Catalysts Supported on Carbon-Nanotubes for Methanol Oxidation

    Institute of Scientific and Technical Information of China (English)

    Hailin Song; Peixia Yang; Xiaoyu Wen; Maozhong An; Jinqiu Zhang

    2015-01-01

    In order to study the properties of supporting Pt catalysts for methanol oxidation, carbon⁃nanotubes are used by electrochemical deposition method. Different deposition turns, different cyclic voltammetry scanning speeds and processing time with ascorbic acid are investigated in this paper. The micrographs of Pt/CNTs catalysts are characterized by scanning electron microscopy, the electro⁃catalytic properties of Pt/CNTs catalysts for methanol oxidation are investigated by cycle voltammetry and chronoamperometry. The results show that the size of platinum will be greater with the faster scanning speed. After dissolution in ascorbic acid, Pt nano⁃particles disperse uniformly. The obtained Pt/CNTs catalysts show a high electro⁃catalytic activity and stability.

  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. 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 [Hf6 O4 (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. PMID:26954885

  5. Direct decomposition of methane over SBA-15 supported Ni, Co and Fe based bimetallic catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Pudukudy, Manoj, E-mail: manojpudukudy@gmail.com [Fuel Cell Institute, Universiti Kebangsaan Malaysia, UKM, Bangi 43600, Selangor (Malaysia); Department of Chemical and Process Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, UKM, Bangi 43600, Selangor (Malaysia); Yaakob, Zahira, E-mail: zahirayaakob65@gmail.com [Department of Chemical and Process Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, UKM, Bangi 43600, Selangor (Malaysia); Akmal, Zubair Shamsul [Department of Chemical and Process Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, UKM, Bangi 43600, Selangor (Malaysia)

    2015-03-01

    Graphical abstract: - Highlights: • Synthesis and characterization of Ni, Co and Fe based bimetallic catalysts supported over SBA-15. • Thermocatalytic decomposition of methane over the SBA-15 supported bimetallic catalysts. • Enhanced catalytic efficiency of the bimetallic catalysts for the production of CO{sub x} free hydrogen and nanocarbon. • Production of value added open tip hollow multi-walled carbon nanotubes. • Crystalline characterization of carbon nanotubes by XRD, Raman and thermogravimetric analysis. - Abstract: Thermocatalytic decomposition of methane is an alternative route for the production of CO{sub x}-free hydrogen and carbon nanomaterials. In this work, a set of novel Ni, Co and Fe based bimetallic catalysts supported over mesoporous SBA-15 was synthesized by a facile wet impregnation route, characterized for their structural, textural and reduction properties and were successfully used for the methane decomposition. The fine dispersion of metal oxide particles on the surface of SBA-15, without affecting its mesoporous texture was clearly shown in the low angle X-ray diffraction patterns and the transmission electron microscopy (TEM) images. The nitrogen sorption analysis showed the reduced specific surface area and pore volume of SBA-15, after metal loading due to the partial filling of hexagonal mesopores by metal species. The results of methane decomposition experiments indicated that all of the bimetallic catalysts were highly active and stable for the reaction at 700 °C even after 300 min of time on stream (TOS). However, a maximum hydrogen yield of ∼56% was observed for the NiCo/SBA-15 catalyst within 30 min of TOS. A high catalytic stability was shown by the CoFe/SBA-15 catalyst with 51% of hydrogen yield during the course of reaction. The catalytic stability of the bimetallic catalysts was attributed to the formation of bimetallic alloys. Moreover, the deposited carbons were found to be in the form of a new set of hollow

  6. TiO2 Nanotubes Supported NiW Hydrodesulphurization Catalysts: Characterization and Activity

    OpenAIRE

    Palcheva, R.; Dimitrov, L; Tyuliev, G.; Spojakina, A.; Jirátová, K.

    2013-01-01

    High surface area TiO2 nanotubes synthesized by alkali hydrothermal method, alumina and titania were used as a support for NiW hydrodesulphurization catalyst. Nickel salt of 12-tungstophosphoric acid (Ni3/2PW12O40) was applied as oxide precursor of the active components. A polytungstate phase evidenced by Raman spectroscopy was observed indicating the destruction of the initial heteropolyanion. Two times higher thiophene conversion was revealed on NiW catalyst supported on TiO2 nanotubes than...

  7. Studies on Co-based catalysts supported on modified carbon substrates for PEMFC cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Subramanian, Nalini P.; Kumaraguru, Swaminatha P.; Colon-Mercado, Hector; Popov, Branko N. [Department of Chemical Engineering, University of South Carolina, Columbia, SC 29208 (United States); Kim, Hansung [Department of Chemical Engineering Yonsei University, Seoul (Korea, Republic of); Black, Timothy; Chen, Donna A. [Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208 (United States)

    2006-06-19

    Cobalt based non-precious metal catalysts were prepared by supporting cobalt-ethylene diamine complex on carbon followed by a heat treatment at elevated temperatures (800{sup o}C). Surface oxygen groups on carbon were introduced with HNO{sub 3} oxidation. Co catalysts supported on oxidized carbon showed improved activity and selectivity towards four-electron reduction of molecular oxygen. Quinone groups introduced by nitric acid treatment, in addition to increasing the dispersion of the chelate complexes, play a role in forming the active site for oxygen reduction. (author)

  8. Synthesis and characterization of supported sugar catalyst by dip coating method

    Science.gov (United States)

    Janaun, J.; Siambun, N. J.; Safie, N. N.

    2016-06-01

    Sugar catalyst is a novel solid acid catalyst with reactivity comparable to that of sulphuric acid in biodiesel production. However, the fine powder form of sugar catalyst with the non-porous structure might cause large pressure drop in a packed bed reactor due to low bed porosity, affecting the reaction conversion especially in gas phase reaction. Furthermore, higher pressure drop requires higher electrical energy to drive the fluid through. Increasing the particle size is anticipated to be able to overcome the pressure drop matter. Hence, a deposition of sugar catalyst on larger particle materials was studied. Three types of materials were used for this investigation namely aluminum, silica and clay. The deposition was done via dip-coating method. The materials were characterized for their total acidity, thermal stability, functional groups, surface area, and element composition. The total acidity for SCDCAl, SCDCSi, and SCDCCl were 0.9 mmol/g, 0.2 mmol/g, and 0.4 mmol/g, respectively. The ratio of char deposited on SCDCAl, SCDCSi and SCDCCl were 0.9 g of support/g of carbon, 0.040 g of support/g of carbon, and 0.014 g of support/g of carbon respectively. FTIR and EDX analyses were carried out to determine the presence of active sites of the catalysis by identifying the functional groups such as -COOH, -OH, -SO3H. The results showed that -SO3H was detected on the surface of synthesized catalysts, except for SCDCC1.The pore size of SCDCAl, SCDCSi and SCDCCl were classified as macropores because the average diameter were greater than 50nm.. The catalysts were stable up to 400°C. The results showed that the dipcoating method could deposit sugar catalyst on aluminum, silica, and clay at low total acidity concentration.

  9. Hydrogenation of cinnamaldehyde using catalysts prepared from supported palladium phosphine complexes

    Energy Technology Data Exchange (ETDEWEB)

    Cairns, G.R.; Cross, R.J.; Stirling, D. [Univ. of Glasgow (United Kingdom)

    1997-02-01

    The liquid phase hydrogenation of cinnamaldehyde has been studied using catalysts prepared from the binuclear palladium complexes [Pd{sub 2}X{sub 4}(PR{sub 3}){sub 2}] (X = Cl, Br, or I; R = Me, Et, and Pr{sup i} or Bu for X =Br only) on silica, and the results have been compared with the performance of a standard Pd/SiO{sub 2} catalyst prepared from Pd(NO{sub 3}){sub 2} and with that of the unsupported molecular complexes. When X = Br, cinnamaldehyde is rapidly hydrogenated selectively to hydrocinnamaldehyde and no further reaction occurs. When X = I, the reactions are extremely slow but are again limited to hydrocinnamaidehyde formation. The catalysts prepared from the chloride-containing precursors behave differently, and some phenyl propanol is formed along with hydrocinnamaldehyde. However, the reaction mechanisms are different from that which operates with the silica-supported palladium catalyst. The rates of the reactions are dependent on the nature of the phosphine substituent, but the selectivities are dependent primarily on the halide. Hydrogenation reactions on all of the catalysts prepared from the binuclear complexes proceed only after an induction period during which partial reduction and/or surface reconstruction of the supported complexes occur. This contrasts with the performance of the standard Pd/SiO{sub 2} catalysts for cinnamaldehyde hydrogenation, which proceeds without any induction period. The reactions of all of these catalysts are thought to take place on a hydrocarbonaceous overlayer which is formed rapidly from unsaturated aldehydes and alcohols. Hydrogenations of cinnamaldehyde using the unsupported complexes in solution proceed at much lower rates, but reveal the same selectivities observed with their silica-supported counterparts. 46 refs., 4 figs., 1 tab.

  10. Efficient oxidative degradation of 2-chlorophenol and 4-chlorophenol over supported CuO-based catalysts

    Institute of Scientific and Technical Information of China (English)

    Jingjing Li; Yang Hu; Wenhui Lü; Lei Shi; Qi Sun; Yonggang Zhou; Jianfeng Xu; Jian Wang; Bizhong Shen

    2011-01-01

    A series of metal oxide catalysts for catalytic oxidative degradation of 2-chlorophenol (2-CP) and 4-chlorophenol (4-CP) were prepared,and the supported CuO catalysts were studied particularly.The supported CuO catalysts were characterized by XRD and NH3-TPD techniques,in which CuO/γ-Al2O3 exhibited high degradation activity.The addition of Na2O or K2O into CuO/γ-Al2O3 improved the oxidative degradation of CPs remarkably,in which Na2O was more efficient than K2O.Over CuO/γ-Al2O3-Na2O,CPs were completely converted and the liberation of the inorganic chloride from 2-CP or 4-CP reached 97% or 100% respectively at 30 ℃ for 2 h.The supported CuO catalysts with good dispersion of CuO particles and less acid sites were favorable for the efficient oxidative degradation of CPs.In addition,the initial pH of the reaction solution was found to be an important factor which influenced the catalytic oxidative degradation of CPs and the initial pH of 11.2 and 9.8 was preferred for the oxidative degradation of 2-CP and 4-CP respectively over CuO/γ-Al2O3 catalyst.

  11. Highly active mesoporous ferrihydrite supported pt catalyst for formaldehyde removal at room temperature.

    Science.gov (United States)

    Yan, Zhaoxiong; Xu, Zhihua; Yu, Jiaguo; Jaroniec, Mietek

    2015-06-01

    Ferrihydrite (Fh) supported Pt (Pt/Fh) catalyst was first prepared by combining microemulsion and NaBH4 reduction methods and investigated for room-temperature removal of formaldehyde (HCHO). It was found that the order of addition of Pt precursor and ferrihydrite in the preparation process has an important effect on the microstructure and performance of the catalyst. Pt/Fh was shown to be an efficient catalyst for complete oxidation of HCHO at room temperature, featuring higher activity than magnetite supported Pt (Pt/Fe3O4). Pt/Fh and Pt/Fe3O4 exhibited much higher catalytic activity than Pt supported over calcined Fh and TiO2. The abundance of surface hydroxyls, high Pt dispersion and excellent adsorption performance of Fh are responsible for superior catalytic activity and stability of the Pt/Fh catalyst. This work provides some indications into the design and fabrication of the cost-effective and environmentally benign catalysts with excellent adsorption and catalytic oxidation performances for HCHO removal at room temperature.

  12. Evaluation of photocatalytic activities of supported catalysts on NaX zeolite or activated charcoal

    Energy Technology Data Exchange (ETDEWEB)

    Brites-Nóbrega, Fernanda F. de [Chemical Engineering Department, Universidade Estadual de Maringá (UEM), Av. Colombo, 5790, CEP 87020-900 Maringá, PR (Brazil); Sanitary and Environmental Engineering Department, Universidade Federal de Minas Gerais (UFMG), Av. Antônio Carlos, 6627, Campus Pampulha, Belo Horizonte, MG (Brazil); Polo, Aldino N.B.; Benedetti, Angélica M. [Chemical Engineering Department, Universidade Estadual do Oeste do Paraná (UNIOESTE), Rua da Faculdade, 645, CEP 85903-000 Toledo, PR (Brazil); Leão, Mônica M.D. [Sanitary and Environmental Engineering Department, Universidade Federal de Minas Gerais (UFMG), Av. Antônio Carlos, 6627, Campus Pampulha, Belo Horizonte, MG (Brazil); Slusarski-Santana, Veronice, E-mail: veronice.santana@unioeste.br [Chemical Engineering Department, Universidade Estadual do Oeste do Paraná (UNIOESTE), Rua da Faculdade, 645, CEP 85903-000 Toledo, PR (Brazil); Fernandes-Machado, Nádia R.C. [Chemical Engineering Department, Universidade Estadual de Maringá (UEM), Av. Colombo, 5790, CEP 87020-900 Maringá, PR (Brazil)

    2013-12-15

    Highlights: • The synergic effect between ZnO and NaX was positive, which increased its activity. • The best results were obtained at pH 3 and 9 with ZnO/NaX and at pH 3 with Nb{sub 2}O{sub 5}/AC. • High degradation and considerable mineralization were attained with 10% ZnO/NaX. • ZnO and Nb{sub 2}O{sub 5} supported on NaX and AC are promising alternatives as photocatalysts. -- Abstract: This study aimed to evaluate the photocatalytic activity of ZnO and Nb{sub 2}O{sub 5} catalysts, both supported on NaX zeolite and activated charcoal (AC). The synergistic effect between oxide and support and the influence of solution pH (3, 7 and 9) on photocatalytic degradation of reactive blue 5G (C.I. 222) were analyzed. The catalysts Nb{sub 2}O{sub 5}/NaX, Nb{sub 2}O{sub 5}/AC and ZnO/NaX, ZnO/AC with 5 and 10% (wt%) were prepared by wet impregnation. The results showed that the catalysts exhibit quite different structural and textural properties. The synergic effect between ZnO and NaX support was higher than that with the activated charcoal, showing that these catalysts were more efficient. The most photoactive catalyst was 10% ZnO/NaX which showed 100% discoloration of the dye solution at pH 3, 7 and 9 after 0.5, 5 and 2 h of irradiation, respectively. The hydrolytic nature of zeolite favored the formation of surface hydroxyl radicals, which increased the activity of the photocatalyst. Thus, catalysts supported on NaX zeolite are promising for use in photocatalysis.

  13. Oxidative desulfurization of synthetic diesel using supported catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Caero, Luis Cedeno; Hernandez, Emiliano [UNICAT, Departamento de Ingenieria Quimica, Facultad de Quimica, UNAM. Cd. Universitaria, 04510 Mexico D.F. (Mexico); Pedraza, Francisco; Murrieta, Florentino [Programa de Tratamiento en Crudo Maya, Instituto Mexicano del Petroleo, Eje Central 152, 07730 Mexico D.F. (Mexico)

    2005-10-30

    In this work, an experimental study was carried out to obtain the reactivity of different organic sulfur compounds and to examine the effect of various parameters, such as temperature, solvent and the amount of oxidant reagent in oxidative desulfurization (ODS) reaction. The oxidation was performed through a vanadium based catalyst in the presence of hydrogen peroxide under mild reaction conditions, atmospheric pressure and temperature range of 303-343K. The sulfur compounds studied were: 2-methylthiophene (2-MT), 2,5-dimethylthiophene (2,5-DMT), benzothiophene (BT), dibenzothiophene (DBT), 4-methyldibenzothiophene (4-MDBT) and 4,6-dimethyl dibenzothiophene (4,6-DMDBT). All of them are typical thiophenic sulfur compounds present in diesel fuels. A synthetic diesel was prepared with these compounds in hexadecane. The experimental results showed that oxidation reactivities decreased according to the following order: DBT>BT>4-MDBT>2-MT>2,5-DMT>4,6-DMDBT. A fraction of the S compounds removed from the diesel phase, was not transformed to its corresponding sulfone, under these experimental conditions. It is only removed as sulfur compound by extraction, without ODS reaction. The surplus amount of oxidant promoted the equilibrium reaction, but the thermal decomposition of oxidant and oxidation reactions produces water, which inhibits the ODS reactions. Therefore, the controlled addition of H{sub 2}O{sub 2} improves ODS reactivity of sulfur compounds.

  14. 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

  15. Studies of supported metal catalysts. Final report, September 1, 1979-April 30, 1984

    Energy Technology Data Exchange (ETDEWEB)

    Hercules, D.M.

    1984-04-01

    A variety of surface spectroscopic techniques, coupled with chemical activity measurements, has been used to study supported heterogeneous catalysts. The catalytic systems investigated are: Ni on Al/sub 2/O/sub 3/ and SiO/sub 2/, Co on Al/sub 2/O/sub 3/, Co and Zn on Al/sub 2/O/sub 3/, Mo on Al/sub 2/O/sub 3/, Mo in TiO/sub 2/, W on Al/sub 2/O/sub 3/, Co and Mo on Al/sub 2/O/sub 3/ and Ni and W on Al/sub 2/O/sub 3/. Emphasis has been on defining the nature of the surface species on the oxidic catalysts, prior to treatment or activation. Reaction of catalysts with H/sub 2/ and H/sub 2/S/H/sub 2/ have been used for diagnosing different species. Treatment with Ha2S/H/sub 2/ also has been used to elucidate the species on sulfided hydrotreating catalysts. Other aspects of the research involved evaluation of photoacoustic spectroscopy for studying catalysts and use of curve resolving techniques to maximize use of ESCA spectra for studying catalysts. In general, the species on catalysts with loadings below monolayer coverage are determined by the nature of the support. For example, on ..gamma..-Al/sub 2/O/sub 3/ distributions of the metal between tetrahedral (Td) and octahedral (Oh) sites occurs. Reactivity of metals in Oh and Td support sites differ; in Mo-Al/sub 2/O/sub 3/ catalysts, the metal in Td sites is reduced only to Mo(+5) by H/sub 2/ (500/sup 0/C) but Oh Mo is reduced to Mo(+4). Sulfiding Mo/Al/sub 2/O/sub 3/ catalysts produces MoS/sub 2/ but leaves some metal unsulfided (Mo+5). Clear evidence for interaction species was found for ternary catalyst systems, viz. Co-Mo-Al/sub 2/O/sub 3/.

  16. The model thin film alumina catalyst support suitable for catalysis-oriented surface science studies

    Energy Technology Data Exchange (ETDEWEB)

    Nartova, Anna V., E-mail: avnartova@gmail.com [Boreskov Institute of Catalysis SB RAS, Lavrentieva Ave., 5, Novosibirsk, 630090 (Russian Federation); Novosibirsk State University, Pirogova St., 2, Novosibirsk, 630090 (Russian Federation); Bukhtiyarov, Andrey V., E-mail: avb@catalysis.ru [Boreskov Institute of Catalysis SB RAS, Lavrentieva Ave., 5, Novosibirsk, 630090 (Russian Federation); Kvon, Ren I., E-mail: kvon@catalysis.ru [Boreskov Institute of Catalysis SB RAS, Lavrentieva Ave., 5, Novosibirsk, 630090 (Russian Federation); Bukhtiyarov, Valerii I., E-mail: vib@catalysis.ru [Boreskov Institute of Catalysis SB RAS, Lavrentieva Ave., 5, Novosibirsk, 630090 (Russian Federation); Novosibirsk State University, Pirogova St., 2, Novosibirsk, 630090 (Russian Federation)

    2015-09-15

    Graphical abstract: - Highlights: • New model catalyst on “AlOx-thin film/FeCrAl” support is presented. • Metal substrate minimizes sample charging, allows fast and uniform heating. • Surface is rough to model the catalyst support's morphology. • Planar alumina is stable in air/gases/solutions and similar to γ-Al{sub 2}O{sub 3}. • New model support is suitable for in situ XPS, STM, TPD, TPR, etc. - Abstract: The preparation of thin continuous alumina film at the surface of metal substrate in UHV (ultra high vacuum) conditions is described. The peculiarities of the obtained films studied by XPS (X-ray photoelectron spectroscopy) and STM (scanning tunneling microscopy) are discussed. The long-term durability of the oxide film was tested and proved both under ambient conditions and in acidic aqueous solutions. The stability of the planar alumina samples toward oxidation by oxygen was checked in the wide ranges of gas pressure and sample temperature. The suggested procedure ensures the controlled and reproducible preparation of thin alumina films – model support appropriate for wet chemistry catalyst preparation, suitable for STM and for other Surface Science techniques studies of alumina supported metal catalysts.

  17. EFFECT OF FOREIGN CARBON ON ACTIVITY OF METHANE COMBUSTION OVER SUPPORTED PALLADIUM CATALYSTS

    Institute of Scientific and Technical Information of China (English)

    Qi Caixia; An Lidun; Wang Hongli

    2001-01-01

    EDTA as precursor of carbon was introduced into Pd(NO3)2 catalysts supported on γ-Al2O3 or 5%MgO/γ-Al2O3. Two kinds of samples,denoted as Pd(NO3)2/[support+EDTA] and [Pd(NO3)2/support]+EDTA, were prepared by changing sequence of impregnating EDTA to the supports. After only being dried they were tested for methane combustion. XPS analyses to the samples at different stages of testing reaction were performed. It was found that the Pd(NO3)2 catalysts became more inactive due to the introduction of EDTA. EDTA in the catalysts was naturally in situ oxidized,partially became into CO2 and escaped, partially coked and deposited on palladium and support with temperature increasing in oxygen-rich atmosphere.Formation of Pd-C solid solution was also confirmed during the reaction. It can be suggested that foreign carbon, in spite of its any existing forms and position in catalysts, inhibits methane combustion largely. The role of carbon on morphological change of palladium during methane combustion was also discussed.

  18. Supported heteronuclear noble metal cluster catalysts and method for preparing same

    International Nuclear Information System (INIS)

    New heteronuclear noble metal cluster complexes have been discovered and synthesized for the first time. These complexes are (pyridine)2Pt(Ir2(CO)15), (pyridine)2 Pt(Ir2(CO)7), (Pyridine)3Pt(Ru3(CO)12), ((C6H5)3P)2Pt(Ir(CO)3(P6H5)3)2, ((C6H5)3P)2Rh(CO)(IR(CO)4), and (pyridine)2Pt(Rh(CO)2(P(C6H5)3)3)2. These new heteronuclear noble metal cluster complexes are useful as supported mixed noble metal catalyst precursors. These new cluster complexes, of known stoichiometry, are deposited on anhydrous refractory inorganic oxide or carbon supports and then reduced resulting in the formation of a supported heteronuclear noble metal catalyst having the same metals stoichiometry as the starting cluster complexes. In this way, precise control can be exercised over the ratio and distribution of multiple metal components in a mixed noble metal catalyst. The usage of preformed heteronuclear noble metal cluster complexes as supported mixed metal catalyst precursors maximizes surface alloy formation and also yields unique mixed-metal cluster structures on the support surface

  19. Effects of K and Pt promoters on the performance of cobalt catalyst supported on CNTs

    Science.gov (United States)

    Zabidi, Noor Asmawati Mohd; Ali, Sardar; Subbarao, Duvvuri

    2014-10-01

    This paper presents a comparative study on the effects of incorporation of potassium (K) and platinum (Pt) as promoters on the physicochemical properties of cobalt catalyst. The catalyst was prepared by a wet impregnation method on a CNTs support. Samples were characterized using transmission electron microscopy (TEM), H2-temperature-programmed reduction (TPR) and X-ray photoelectron spectroscopy (XPS) techniques. Fischer-Tropsch Synthesis (FTS) was carried out in a fixed-bed microreactor at 543 K and 1 atm, with H2/ CO = 2v / v and space velocity, SV of 12 L/g.h for 5 hours. The K-promoted and Pt-promoted Co catalysts have different physicochemical properties and catalytic performances compared to that of the un-promoted Co catalyst. XPS analysis revealed that K and Pt promoters induced electronic modifications as exhibited by the shifts in the Co binding energies. Incorporation of 0.06 wt% K and 0.06 wt% Pt in Co/CNTs catalyst resulted in an increase in the CO conversion and C5+ selectivity and a decrease in methane selectivity. Potassium was found to be a better promoter for Co/CNTs catalyst compared to platinum.

  20. Effects of K and Pt promoters on the performance of cobalt catalyst supported on CNTs

    Energy Technology Data Exchange (ETDEWEB)

    Zabidi, Noor Asmawati Mohd, E-mail: noorasmawati-mzabidi@petronas.com.my [Department of Fundamental and Applied Sciences, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750 Tronoh, Perak (Malaysia); Ali, Sardar, E-mail: alikhan-635@yahoo.com [Centralized Analytical Laboratory, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750 Tronoh, Perak (Malaysia); Subbarao, Duvvuri, E-mail: duvvuri-subbarao@petronas.com.my [Department of Chemical Engineering, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750 Tronoh, Perak (Malaysia)

    2014-10-24

    This paper presents a comparative study on the effects of incorporation of potassium (K) and platinum (Pt) as promoters on the physicochemical properties of cobalt catalyst. The catalyst was prepared by a wet impregnation method on a CNTs support. Samples were characterized using transmission electron microscopy (TEM), H{sub 2}-temperature-programmed reduction (TPR) and X-ray photoelectron spectroscopy (XPS) techniques. Fischer-Tropsch Synthesis (FTS) was carried out in a fixed-bed microreactor at 543 K and 1 atm, with H{sub 2}/CO = 2v/v and space velocity, SV of 12 L/g.h for 5 hours. The K-promoted and Pt-promoted Co catalysts have different physicochemical properties and catalytic performances compared to that of the un-promoted Co catalyst. XPS analysis revealed that K and Pt promoters induced electronic modifications as exhibited by the shifts in the Co binding energies. Incorporation of 0.06 wt% K and 0.06 wt% Pt in Co/CNTs catalyst resulted in an increase in the CO conversion and C{sub 5+} selectivity and a decrease in methane selectivity. Potassium was found to be a better promoter for Co/CNTs catalyst compared to platinum.

  1. 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

    2016-02-01

    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.

  2. Supported noble metal catalysts in the catalytic wet air oxidation of industrial wastewaters and sewage sludges.

    Science.gov (United States)

    Besson, M; Descorme, C; Bernardi, M; Gallezot, P; di Gregorio, F; Grosjean, N; Minh, D Pham; Pintar, A

    2010-12-01

    This paper reviews some catalytic wet air oxidation (CWAO) investigations of industrial wastewaters over platinum and ruthenium catalysts supported on TiO2 and ZrO2 formulated to be active and resistant to leaching, with particular focus on the stability of the catalyst. Catalyst recycling experiments were performed in batch reactors and long-term stability tests were conducted in trickle-bed reactors. The catalyst did not leach upon treatment of Kraft bleaching plant and olive oil mill effluents, and could be either recycled or used for long periods of time in continuous reactors. Conversely, these catalysts were rapidly leached when used to treat effluents from the production of polymeric membranes containing N,N-dimethylformamide. The intermediate formation of amines, such as dimethylamine and methylamine with a high complexing capacity for the metal, was shown to be responsible for the metal leaching. These heterogeneous catalysts also deactivated upon CWAO of sewage sludges due to the adsorption of the solid organic matter. Pre-sonication of the sludge to disintegrate the flocs and improve solubility was inefficient. PMID:21214003

  3. Catalytic decomposition of N₂O over CeO₂ supported Co₃O₄ catalysts

    Indian Academy of Sciences (India)

    S K MAHAMMADUNNISA; T AKANKSHA; K KRUSHNAMURTY; CH SUBRAHMANYAM

    2016-11-01

    This work was aimed to design efficient catalysts for N₂O decomposition at low temperatures. Cobalt oxide (Co₃O₄) was prepared by hydrothermal, precipitation and combustion methods and tested for N₂O decomposition. It was found that the catalysts prepared by solution combustion synthesis were most active for this reaction. Subsequently, a series of ceria (CeO₂) supported Co₃O₄ catalysts (xCeCo) were prepared by solution combustion method and used them for N₂O decomposition. All the catalysts were characterized by analytical methods like XRD, TEM, BET, XPS, UV-Vis, Raman and H2-TPR. It was found that 10 and 20 wt..% loading of CeO₂ on Co₃O₄ promoted the activity of Co₃O₄ towards N₂O decomposition, whereas, higher loading of CeO₂ reduced the activity. Typical results indicated that addition of CeO₂ increases the surface area of Co₃O₄ , and improves the reduction of Co³⁺ to Co²⁺ by facilitating the desorption of adsorbed oxygen species, which is the rate-determining step for the N₂O decomposition over Co₃O₄ spinel catalysts. Optimal CeO₂ loading can increase both dispersion and surface area of Co₃O₄ catalysts and weaken the Co–O bond strength to promote N₂O decomposition.

  4. Metal Chlorides Supported Solid Catalysts for F-C Acylations of Arenes

    Institute of Scientific and Technical Information of China (English)

    李阳; 刘云龙; 穆曼曼; 陈立功

    2015-01-01

    A series of metal chlorides supported solid catalysts were prepared by simple wet impregnation method. Their catalytic performances for Friedel-Crafts acylation of toluene with benzoyl chloride were evaluated and the excellent results were obtained over FeCl3/SiO2. These catalysts were characterized by BET, NH3-TPD and FT-IR of pyridine adsorption to clarify the structure-activity relationship. It was found that FeCl3/SiO2 has larger pore size and pore volume than other catalysts, which increased the accessibility of the catalyst. In addition, FeCl3/SiO2 ex-hibited higher molar ratio of Lewis acid sites and Brφnsted acid sites, which might be another reason for the in-crease of toluene conversion. Furthermore, the reaction parameters, including temperature, time and molar ratio, were optimized. Under the optimized conditions, 91.2%, conversion and 82.0%, selectivity were obtained. Mean-while, the generality of the catalyst was demonstrated by the acylations of alkyl substituted aromatics. Finally, the catalyst was reused for four runs with slight loss in catalytic activity, which attributed to the drain of the active component.

  5. 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.

  6. 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.

  7. Ni supported on activated carbon as catalyst for flue gas desulfurization

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A series of Ni supported on activated carbon are prepared by excessive impregnation and the desulfurization activity is investigated. It has been shown that the activated carbon-supported Ni is an efficient solid catalyst for flue gas desulfurization. The activated carbon treated by HNO3 exhibits high desulfurization activity, and different amounts of loaded-Ni on activated carbon significantly influence the desulfurization activity. The catalysts are studied by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The results of XRD and XPS indicate that the activated carbon treated by HNO3 can increase oxygen-containing functional groups. Ni on activated carbon after calcination at 800 °C shows major Ni phase and minor NiO phase, and with increasing Ni content on activated carbon, Ni phase increases and affects the desulfurization activity of the catalyst, which proves that Ni is the main active phase.

  8. 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...... the large surface area and good anchoring properties make it a suited material for this purpose, it is prone to degradation in the fuel-cell environment. Thus alternative materials with higher durability than CB, but with similar (or better) capability of dispersion, are desired. Among them are highly...... 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...

  9. Selective Oxidation of Isobutane to Methacrylic Acid over Supported V-Mo-P Based Composite Oxide Catalysts

    Institute of Scientific and Technical Information of China (English)

    Feifei Sun; Yunfeng Geng; Shunhe Zhong

    2002-01-01

    Heteropolyacid, the most popular catalyst for the direct oxidation of isobutane, exhibits high catalytic activity, poor thermal stability and a short lifetime. Therefore, the catalyst requires further research to improve its performance. Catalysts composed of mixed oxides (V2O5, P2O5, or MoO3) supported on silica were prepared by the sol-gel method to catalyze the reaction. Results of XRD, IR, and BET corroborated that the mixed oxides were dispersed homogeneously on the surface of support. The activity of lattice oxygen in the catalysts was studied by TPR, and the chemisorption property of isobutane on the surface of the catalysts was investigated by the TPD method. H2-TPR of the catalysts revealed that the lattice oxygen of the vanadium-based catalysts is more active than that of the molybdenum-based catalysts. The rcdox property of V or Mo species is slightly affected by other compositions of the series catalysts. The TPD curves illustrate that there are two kinds of adsorptive species of isobutane on the surface of the V and Mo based catalysts. The adsorbing species on the VMoP/SiO2 catalyst are identical to the main adsorbing species on VP/SiO2 and MoP/SiO2. The catalyst VMoP/SiO2 is more active than others in the selective oxidation of isobutane.

  10. Structure sensitive adsorption of hydrogen on ruthenium and ruthenium-silver catalysts supported on silica

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, N.

    1999-02-12

    Supported metal catalysts typically consist of particles with sizes less than 10 nm, and because of the small crystallite size, low coordination number sites (edges and corners) represent a significant fraction of all surface sites. Furthermore, it has been demonstrated that adsorption rates can be much greater at these low coordination sites than on basal plane sites. What has not been generally appreciated, however, is that preferential adsorption at edge and corner sites may explain the mechanism by which a promoter, or the addition of a second metal to form a bimetallic, can alter the selectivity and rate of reaction. For example, the measurements of hydrogen adsorption onto supported Ru-Ag catalysts show marked decreases in the amount of hydrogen adsorbed relative to the amount adsorbed on Ru catalysts. Although it is known that Ag does not dissociatively adsorb hydrogen, this decrease cannot be explained by a simple one-to-one site blocking mechanism unless Ag preferentially populates edges and corners, thereby reducing the number of Ru edge sites. Indeed, Monte Carlo simulations of Ru-Group IB metal catalysts predict that Group IB metal atoms preferentially populate corner and edge sites of ruthenium crystals. This evidence, taken together, suggests that adsorption occurs preferentially at Ru corner and edge sites, which act as portals onto basal planes. A model based on this portal theory for hydrogen adsorption onto supported ruthenium bimetallic catalysts has been developed using a rate equation approach. Specifically, the model accounts for the following features: (1) preferential adsorption through portals, (2) basal plane site-energy multiplicity, and (3) hydrogen spillover onto the support. A comparison of model predictions with experiment is presented for different concentration of Ag in Ru-Ag catalysts. The portal model of hydrogen adsorption can explain the observed decreased in the amount of hydrogen adsorbed on Ru-Ag catalysts. The model can be

  11. 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.

  12. Highly active and stable platinum catalyst supported on porous carbon nanofibers for improved performance of PEMFC

    International Nuclear Information System (INIS)

    Porous carbon nanofibers (PCNFs) were used as the support to prepare platinum (Pt) catalyst (Pt/PCNFs) for proton exchange membrane fuel cell (PEMFC) applications. As a comparison, Pt supported on carbon black (Vulcan XC-72) (Pt/Vulcan) was also synthesized by the same ethylene glycol reduction method. Platinum was more uniformly deposited on PCNFs than that on the Vulcan XC-72. The electrocatalytic activity and stability of the resultant catalysts along with the commercial one (JM20) were investigated using cyclic voltammetry (CV) and linear sweep voltammetry (LSV) with a rotating disk electrode (RDE). The Pt/PCNFs exhibited much-enhanced electrocatalytic activity and stability compared with the Pt/Vulcan and JM20. The mass activity (at 0.80 V) of Pt/PCNFs is 2.6 times higher and 20% higher than that of Pt/Vulcan and JM20, respectively; the Pt/PCNFs retained about 50% of ECSA whereas JM20 and Pt/Vulcan kept only 25% and 5% of ECSA, respectively, even after 1000 cycles. Furthermore, the single cell performance of Pt/PCNFs was superior to that of Pt/Vulcan and even better than JM20 during high current densities. The cross-section of the membrane electrode assembly (MEA) showed that the Pt/PCNFs construct a loose three-dimensionally connected catalyst layer that is totally different from the tightly stacking catalyst layer composed of carbon black support. Thus, the mass transfer resistance is reduced and water drainage becomes easy when Pt/PCNFs were used as cathode catalyst. These results indicate PCNFs a promising candidate as catalyst supports for the enhancement of PEMFC performance

  13. 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.

  14. A Review on Metal-support Interaction in Automotive Catalysts

    Institute of Scientific and Technical Information of China (English)

    ZHENG Tingting; HE Junjun; WANG Song; LU Jun; ZHAO Yunkun

    2012-01-01

    TWC-equipped exhausts are widely used in gasoline-fueled vehicles to meet stringent emission regulations.The main components in TWCs are precious metals such as palladium (Pd),platinum (Pt),and rhodium (Rh) as the active component,and inorganic oxides such as γ-alumina (Al2O3),ceria (CeO2),zirconia (ZrO2) and ceria-zirconia (CeO2-ZrO2) are used as the support.Interaction of precious metals and support plays an important role in the thermal stability and catalytic performance of TWCs.The support can improve the dispersion of precious metals and suppress the sintering of precious metals at high temperature.In the same,precious metals can also enhance the redox performance and oxygen storage capacity of support.This paper reviews the reaction phenomenon and mechanism of precious metals (Pt,Pd,Rh) and supports such as Al2O3,CeO2-based composite oxides.

  15. Study of different nanostructured carbon supports for fuel cell catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Mirabile Gattia, Daniele; Antisari, Marco Vittori; Giorgi, Leonardo; Marazzi, Renzo; Montone, Amelia [Department of Physical Methods and Materials, ENEA, Research Centre of Casaccia, Via Anguillarese 301, 00123 Rome (Italy); Piscopiello, Emanuela [Department of Physical Methods and Materials, ENEA, Research Centre of Brindisi, Via Appia Km 702, 72100 Brindisi (Italy); Bellitto, Serafina; Licoccia, Silvia; Traversa, Enrico [Dipartimento di Scienze e Tecnologie Chimiche, Universita di Roma ' ' Tor Vergata' ' , Via della Ricerca Scientifica, 00133 Rome (Italy)

    2009-10-20

    Pt clusters were deposited by an impregnation process on three carbon supports: multi-wall carbon nanotubes (MWNT), single-wall carbon nanohorns (SWNH), and Vulcan XC-72 carbon black to investigate the effect of the carbon support structure on the possibility of reducing Pt loading on electrodes for direct methanol (DMFC) fuel cells without impairing performance. MWNT and SWNH were in-house synthesised by a DC and an AC arc discharge process between pure graphite electrodes, respectively. UV-vis spectrophotometry, scanning and transmission electron microscopy, X-ray diffraction, and cyclic voltammetry measurements were used to characterize the Pt particles deposited on the three carbon supports. A differential yield for Pt deposition, not strictly related to the surface area of the carbon support, was observed. SWNH showed the highest surface chemical activity toward Pt deposition. Pt deposited in different forms depending on the carbon support. Electrochemical characterizations showed that the Pt nanostructures deposited on MWNT are particularly efficient in the methanol oxidation reaction. (author)

  16. 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.

  17. Deep hydrodesulphurization and hydrogenation of diesel fuels on alumina-supported and bulk molybdenum carbide catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Patrick Da Costa; Claude Potvin; Jean-Marie Manoli; Benoit Genin; Gerald Djega-Mariadassou [Universite P. et M. Curie, Paris (France). Laboratoire Reactivite de Surface

    2004-09-01

    Deep hydrodesulphurization (HDS) of diesel fuels has been carried out on P (Ni)-promoted or non-promoted Mo{sub 2}2C-supported {gamma}Al{sub 2}O{sub 3} and bulk Mo{sub 2}C under standard industrial conditions (613 K, 3 MPa). The effect of the promoter was investigated for different feedstocks on HDS and hydrogenation (HYD) with very low levels of sulfur. The temperature effect was also followed. The HDS conversion indicates that phosphorus promoted alumina supported carbide catalysts are as active as a commercial Co-Mo/Al{sub 2}O{sub 3} catalyst for low levels of sulfur in the feed. Furthermore, the refractory compounds such as 4,6-dimethyldibenzothiophene are only transformed on molybdenum carbide catalyst in industrial conditions for hydrotreated gas oils. With gas oils with less than 50 wt ppm in sulfur, phosphorus promoted molybdenum carbide catalysts become more active than commercial catalysts for the HYD of the aromatic compounds and the HDS or the HDN of the feedstock. 35 refs., 8 figs., 6 tabs.

  18. 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. PMID:27240230

  19. Sintering-Resistant Single-Site Nickel Catalyst Supported by Metal-Organic Framework.

    Science.gov (United States)

    Li, Zhanyong; Schweitzer, Neil M; League, Aaron B; Bernales, Varinia; Peters, Aaron W; Getsoian, Andrew Bean; Wang, Timothy C; Miller, Jeffrey T; Vjunov, Aleksei; Fulton, John L; Lercher, Johannes A; Cramer, Christopher J; Gagliardi, Laura; Hupp, Joseph T; Farha, Omar K

    2016-02-17

    Developing supported single-site catalysts is an important goal in heterogeneous catalysis since the well-defined active sites afford opportunities for detailed mechanistic studies, thereby facilitating the design of improved catalysts. We present herein a method for installing Ni ions uniformly and precisely on the node of a Zr-based metal-organic framework (MOF), NU-1000, in high density and large quantity (denoted as Ni-AIM) using atomic layer deposition (ALD) in a MOF (AIM). Ni-AIM is demonstrated to be an efficient gas-phase hydrogenation catalyst upon activation. The structure of the active sites in Ni-AIM is proposed, revealing its single-site nature. More importantly, due to the organic linker used to construct the MOF support, the Ni ions stay isolated throughout the hydrogenation catalysis, in accord with its long-term stability. A quantum chemical characterization of the catalyst and the catalytic process complements the experimental results. With validation of computational modeling protocols, we further targeted ethylene oligomerization catalysis by Ni-AIM guided by theoretical prediction. Given the generality of the AIM methodology, this emerging class of materials should prove ripe for the discovery of new catalysts for the transformation of volatile substrates. PMID:26836273

  20. Sintering-resistant Single-Site Nickel Catalyst Supported by Metal-Organic Framework

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zhanyong; Schweitzer, Neil; League, Aaron; Bernales Candia, Sandra Varinia; Peters, Aaron; Getsoian, Andrew G.; Wang, Timothy; Miller, Jeffrey T.; Vjunov, Aleksei; Fulton, John L.; Lercher, Johannes A.; Cramer, Christopher J.; Gagliardi, Laura; Hupp, Joseph; Farha, Omar

    2016-02-17

    Developing supported single-site catalysts is an important goal in heterogeneous catalysis, since the well-defined active sites afford opportunities for detailed mechanistic studies, thereby facilitating the design of improved catalysts. We present herein a method for installing Ni ions uniformly and precisely on the node of a Zr-based MOF, NU-1000, in high density and large quantity (denoted as Ni-AIM) using atomic layer deposition (ALD) in a metal–organic framework (MOF) (AIM). Ni-AIM is demonstrated to be an efficient gas-phase hydrogenation catalyst upon activation. The structure of the active sites in Ni-AIM is proposed, revealing its single-site nature. More importantly, due to the organic linker used to construct the MOF support, the Ni ions stay isolated throughout the hydrogenation catalysis, in accord with its long-term stability. A quantum chemical characterization of the catalyst and the catalytic process complements the experimental results. With validation of computational modeling protocols, we further targeted ethylene oligomerization catalysis by Ni-AIM guided by theoretical prediction. Given the generality of the AIM methodology, this emerging class of materials should prove ripe for the discovery of new catalysts for the transformation of volatile substrates.

  1. Magnetically Recoverable Supported Ruthenium Catalyst for Hydrogenation of Alkynes and Transfer Hydrogenation of Carbonyl Compounds

    Science.gov (United States)

    A ruthenium (Ru) catalyst supported on magnetic nanoparticles (NiFe2O4) has been successfully synthesized and used for hydrogenation of alkynes at room temperature as well as transfer hydrogenation of a number of carbonyl compounds under microwave irradiation conditions. The cata...

  2. Carboxylic Group Embedded Carbon Balls as a New Supported Catalyst for Hydrogen Economic Reactions.

    Science.gov (United States)

    Bordoloi, Ankur

    2016-03-01

    Carboxylic group functionalized carbon balls have been successfully synthesized by using a facile synthesis method and well characterized with different characterization techniques such as XPS, MAS NMR, SEM, ICP and N2 physi-sorption analysis. The synthesized material has been effectively utilized as novel support to immobilized ruthenium catalyst for hydrogen economic reactions. PMID:27455763

  3. Phosphite Ligand Modified Supported Rhodium Catalyst for Hydroformylation of Internal Olefins to Linear Aldehydes

    Institute of Scientific and Technical Information of China (English)

    LI Xian-ming; DING Yun-jie; JIAO Gui-ping; LI Jing-wei; YAN Li; ZHU He-jun

    2009-01-01

    A phosphite ligand modified heterogeneous catalyst was developed for the hydroformylation of internal olefins to linear aldehydes, which showed a high activity and high regioselectivity and could be separated easily by filtration after reaction in an autoclave. Three nanoporous silica sieves were used to investigate the influence of pore structure and shape selective performance of support on the regioselectivity to the linear products.

  4. Stability of cobalt supported on ZrO{sub 2} catalysts for methane combustion

    Energy Technology Data Exchange (ETDEWEB)

    Milt, V.G.; Lombardo, E.A.; Ulla, M.A. [Instituto de Investigaciones en Catalisis y Petroquimica, INCAPE FIQ, UNL-CONICET, Santiago del Estero 2829, 3000 Santa Fe (Argentina)

    2002-04-08

    Cobalt supported catalysts were prepared by two different techniques: atomic layer epitaxy (ALE) and wet impregnation. Either ZrO{sub 2} or La/ZrO{sub 2} (La-doped ZrO{sub 2}) were used as supports. The solids were characterized by XRD, TPR and XPS before and after hydrothermal and catalytic stability tests (TOS: 150h, 970K). The most active catalysts were those in which cobalt was incorporated using the epitaxial growth technique. Moreover, the initial activity of cobalt supported on ZrO{sub 2} by ALE was significantly higher than that on La/ZrO{sub 2}. But, after maintaining the former catalysts for 150h at 970K on stream (stability test), their initial high activities significantly decreased. On the other hand, when Co was supported on La-doped ZrO{sub 2} the resulting catalysts became much more stable. Combining the catalytic results with the characterization information a simple model is proposed that rationalizes the behavior of these solids.

  5. Alkene Isomerization Using a Solid Acid as Activator and Support for a Homogeneous Catalyst

    Science.gov (United States)

    Seen, Andrew J.

    2004-01-01

    An upper-level undergraduate experiment that, in addition to introducing students to catalysis using an air sensitive transition-metal complex, introduces the use of a solid acid as an activator and support for the catalyst is developed. The increased stability acquired in the course of the process affords the opportunity to characterize the…

  6. Synergy between metals in bimetallic zeolite supported catalyst for NO-promoted N2O decomposition

    NARCIS (Netherlands)

    Pieterse, J.A.Z.; Mul, G.; Melian-Cabrera, I.; van den Brink, R.W.

    2005-01-01

    The detrimental effect of NO on N2O decomposition over zeolite supported noble metal catalysts can be (partly) eliminated by combining noble metal with iron or cobalt. In the presence of NO, the total conversion of N2O over these bimetallic-zeolites exceeds the sum of conversions over the monometall

  7. Carbon Supported Polyaniline as Anode Catalyst: Pathway to Platinum-Free Fuel Cells

    CERN Document Server

    Zabrodskii, A G; Malyshkin, V G; Sapurina, I Y

    2006-01-01

    The effectiveness of carbon supported polyaniline as anode catalyst in a fuel cell (FC) with direct formic acid electrooxidation is experimentally demonstrated. A prototype FC with such a platinum-free composite anode exhibited a maximum room-temperature specific power of about 5 mW/cm2

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

    NARCIS (Netherlands)

    Frey, A.M.; van Haasterecht, T.; de Jong, 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

  9. Carboxylic Group Embedded Carbon Balls as a New Supported Catalyst for Hydrogen Economic Reactions.

    Science.gov (United States)

    Bordoloi, Ankur

    2016-03-01

    Carboxylic group functionalized carbon balls have been successfully synthesized by using a facile synthesis method and well characterized with different characterization techniques such as XPS, MAS NMR, SEM, ICP and N2 physi-sorption analysis. The synthesized material has been effectively utilized as novel support to immobilized ruthenium catalyst for hydrogen economic reactions.

  10. X-Ray Absorption Characterization of Supported Palladium Catalysts : A Comparison with Hydrogen Chemisorption

    OpenAIRE

    Zhang, G.; Habib, M; Vittoratos, S.

    1997-01-01

    X-ray absorption spectroscopy was used to characterize the supported palladium hydrocracking catalysts. Results with regard to the percentage of metal exposed are compared with those from hydrogen chemisorption measurements. Results from XAS indicate that hydrogen chemisorption has underestimated the metal dispersion. Possible explanations for this discrepancy are discussed.

  11. 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 imp...

  12. Selective oxidation of methyl alpha-d-glucoside on carbon supported platinum catalysts. Doctoral thesis

    Energy Technology Data Exchange (ETDEWEB)

    Schuurman, Y.

    1992-01-27

    The selective oxidation of methyl alpha-D-glucoside to sodium 1-O-methyl alpha-D-glucuronate by molecular oxygen on supported platinum was studied in a three-phase agitated tank reactor. Emphasis was put on the intrinsic kinetics and on the catalyst deactivation during oxidation. The obtained results were applied to the design of an industrial production unit.

  13. 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...

  14. Strategies for designing supported gold-palladium bimetallic catalysts for the direct synthesis of hydrogen peroxide.

    Science.gov (United States)

    Edwards, Jennifer K; Freakley, Simon J; Carley, Albert F; Kiely, Christopher J; Hutchings, Graham J

    2014-03-18

    Hydrogen peroxide is a widely used chemical but is not very efficient to make in smaller than industrial scale. It is an important commodity chemical used for bleaching, disinfection, and chemical manufacture. At present, manufacturers use an indirect process in which anthraquinones are sequentially hydrogenated and oxidized in a manner that hydrogen and oxygen are never mixed. However, this process is only economic at a very large scale producing a concentrated product. For many years, the identification of a direct process has been a research goal because it could operate at the point of need, producing hydrogen peroxide at the required concentration for its applications. Research on this topic has been ongoing for about 100 years. Until the last 10 years, catalyst design was solely directed at using supported palladium nanoparticles. These catalysts require the use of bromide and acid to arrest peroxide decomposition, since palladium is a very active catalyst for hydrogen peroxide hydrogenation. Recently, chemists have shown that supported gold nanoparticles are active when gold is alloyed with palladium because this leads to a significant synergistic enhancement in activity and importantly selectivity. Crucially, bimetallic gold-based catalysts do not require the addition of bromide and acids, but with carbon dioxide as a diluent its solubility in the reaction media acts as an in situ acid promoter, which represents a greener approach for peroxide synthesis. The gold catalysts can operate under intrinsically safe conditions using dilute hydrogen and oxygen, yet these catalysts are so active that they can generate peroxide at commercially significant rates. The major problem associated with the direct synthesis of hydrogen peroxide concerns the selectivity of hydrogen usage, since in the indirect process this factor has been finely tuned over decades of operation. In this Account, we discuss how the gold-palladium bimetallic catalysts have active sites for the

  15. 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

  16. 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.

  17. 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)

  18. Ultrastable single-atom gold catalysts with strong covalent metal-support interaction (CMSI)

    Institute of Scientific and Technical Information of China (English)

    Botao Qiao[1; Jin-Xia Liang[3,4; Aiqin Wang[2; Cong-Qiao Xu[3; Jun Li[3; Tao Zhang[2; Jingyue (Jimmy) Liu[1

    2015-01-01

    Supported noble metal nanoparticles (including nanoclusters) are widely used in many industrial catalytic processes. While the finely dispersed nanostructures are highly active, they are usually thermodynamically unstable and tend to aggregate or sinter at elevated temperatures. This scenario is particularly true for supported nanogold catalysts because the gold nanostructures are easily sintered at high temperatures, under reaction conditions, or even during storage at ambient temperature. Here, we demonstrate that isolated Au single atoms dispersed on iron oxide nanocrystallites (Aul/FeOx) are much more sintering- resistant than Au nanostructures, and exhibit extremely high reaction stability for CO oxidation in a wide temperature range. Theoretical studies revealed that the positively charged and surface-anchored Aul atoms with high valent states formed significant covalent metal-support interactions (CMSIs), thus providing the ultra-stability and remarkable catalytic performance. This work may provide insights and a new avenue for fabricating supported Au catalysts with ultra-high stability.

  19. New Construction and Catalyst Support Materials for Water Electrolysis at Elevated Temperatures

    DEFF Research Database (Denmark)

    Nikiforov, Aleksey

    showed the in uence of the support on the packing of IrO2 particles. Investigation showed that even a support material with poor electrical conductivity contributes beneficially to the electrocatalyst active surface area, increasing its utilization. Results demonstrated potential perspectives of using...... in Chapter 5. The active iridium oxide was deposited on the SiC-Si in-situ by the Adams fusion synthesis and characterized by different techniques. XRD and nitrogen adsorption experiments showed an influence of the support on surface properties of the IrO2 particles, affecting IrO2 particle size....... The prepared catalysts were electrochemically characterized by cyclic voltammetry experiments at 25, 80, 120 and 150 °C. In accordance with the observed variation in particle size, a support loading of up to 80% improved the activity of the catalyst. Powder conductivity measurements were also performed, which...

  20. POLYMER—SUPPORTED RHODIUM CATALYSTS FOR CARBONYLATION OF METHYL ACETATE TO ACETIC ANHYDRIDE

    Institute of Scientific and Technical Information of China (English)

    CHENDean; HUANGShizhuan; 等

    1993-01-01

    Two kinds of rhodium catalysts supported on cross-linked styrene-divinylbenzene copolymers containing bipyridine or o-phenylene diamine have been prepared and found to display high activity for methyl acetate carbonylation to form acetic anhydride,the activities are even higher than their homogeneous counterparts. XPS analysis was used to characterize the synthetic catalysts.The apparent activation parameters were determined to be Eα=73.3KJ/mol,ΔH≠=66.3KJ/mol,ΔS≠=-28.6eu.These parameters are very close to those in methanol carbonylation and imply to have analogous mechanism in both cases.

  1. 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.

  2. An Efficient and Recyclable Nanoparticle-Supported Cobalt Catalyst for Quinoxaline Synthesis.

    Science.gov (United States)

    Rajabi, Fatemeh; Alves, Diego; Luque, Rafael

    2015-11-19

    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.

  3. MgO-SBA-15 Supported Pd-Pb Catalysts for Oxidative Esterification of Methacrolein with Methanol to Methyl Methacrylate☆

    Institute of Scientific and Technical Information of China (English)

    Li Jiang; Yanyan Diao; Junxing Han; Ruiyi Yan; Xiangping Zhang; Suojiang Zhang

    2014-01-01

    Novel MgO–SBA-15 supported catalysts were prepared for oxidative esterification of methacrolein (MAL) with methanol to methyl methacrylate (MMA). The MgO–SBA-15 supports were synthesized with different magnesia loadings from different magnesium precursors and hydrochloric acid molar concentrations. The MgO–SBA-15 sup-ports and Pd–Pb/MgO–SBA-15 catalysts were characterized by several analysis methods. The results revealed that the addition of MgO improved the ordered structure of SBA-15 supports and provided surface alkalinity of SBA-15 supports. The average size of the Pd3Pb particles on magnesia-modified Pd–Pb/MgO–SBA-15 catalysts was smal er than that on the pure silica-based Pd–Pb/SBA-15 catalysts. The experiments on catalyst performance showed that the magnesia-modified Pd–Pb/MgO–SBA-15 catalysts had higher activity than pure silica-based Pd–Pb/SBA-15 catalysts, showing the strong dependence of catalytic activity on the average size of active particles. The difference of activity between Pd–Pb/SBA-15 catalysts and Pd–Pb/MgO–SBA-15 catalysts was due to the discrepant structural properties and surface alkalinity provided by MgO, which led to the different Pd3Pb particle sizes and then resulted in the different number of active sites. Besides magnesia loadings, other factors, such as hydrochloric acid molar concentration and magnesium precursors, had considerable influences on the catalytic activity.

  4. 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

  5. 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.

  6. 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.

  7. In situ synthesis of nano clay filled polyethylene using polymer support metallocenes catalyst system

    International Nuclear Information System (INIS)

    In situ ethylene polymerizations were performed using bis(cyclopentadiene)titanium dichloride supported on poly ethersulfone as catalyst. The bis(cyclopentadiene)titanium dichloride supported on poly ethersulfone catalyst activity estimated by ethylene polymerization was 360 kg PE/mol Ti/h. During polymerization the fillers used were montmorillonite nano clays having surface modifications with 35-45 wt % dimethyl dialkyl(14-18)amine (FA) and 25-30 wt % trimethyl stearyl ammonium (FB). These fillers were pretreated with methylaluminoxine (MAO; co catalyst) 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 nano filler did not have any remarkable effect on the melting characteristics of the polymer. TGA study indicates that nano clay FB filled polyethylene has higher thermal stability than nano clay FA filled polyethylene. The melting temperature of the obtained polyethylenes was 142 degree C, which corresponds to that synthesized by the polyether sulfone supported catalyst. (author)

  8. Gold-supported cerium-doped NiOx catalysts for water oxidation

    Science.gov (United States)

    Ng, Jia Wei Desmond; García-Melchor, Max; Bajdich, Michal; Chakthranont, Pongkarn; Kirk, Charlotte; Vojvodic, Aleksandra; Jaramillo, Thomas F.

    2016-05-01

    The development of high-performance catalysts for the oxygen-evolution reaction (OER) is paramount for cost-effective conversion of renewable electricity to fuels and chemicals. Here we report the significant enhancement of the OER activity of electrodeposited NiOx films resulting from the combined effects of using cerium as a dopant and gold as a metal support. This NiCeOx-Au catalyst delivers high OER activity in alkaline media, and is among the most active OER electrocatalysts yet reported. On the basis of experimental observations and theoretical modelling, we ascribe the activity to a combination of electronic, geometric and support effects, where highly active under-coordinated sites at the oxide support interface are modified by the local chemical binding environment and by doping the host Ni oxide with Ce. The NiCeOx-Au catalyst is further demonstrated in a device context by pairing it with a nickel-molybdenum hydrogen evolution catalyst in a water electrolyser, which delivers 50 mA consistently at 1.5 V over 24 h of continuous operation.

  9. Solid state NMR investigation of silica aerogel supported Fischer-Tropsch catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Zhiru; Dunn, Brian C.; Turpin, Gregory C.; Eyring, Edward M.; Ernst, Richard D.; Pugmire, Ronald J. [Department of Chemistry, University of Utah, Salt Lake City, UT 84112 (United States)

    2007-01-15

    The Fischer-Tropsch (F-T) catalyst is the critical component for the F-T synthesis of a variety of hydrocarbons from syngas. Fischer-Tropsch cobalt, iron and ruthenium catalysts supported on silica aerogel have been prepared using a combination of sol-gel chemistry and vapor phase deposition methods. Solid state NMR spectroscopy, a very powerful technique for analyzing the structure and dynamics of various materials, was employed in the study of these F-T catalyst systems. The silica aerogel supported F-T catalysts have been investigated using both solid state {sup 29}Si and {sup 13}C NMR methods. The silica aerogel's tetrahedral sub-unit structure and the influence of the loaded metal compounds have been observed. Three types of Si(O{sub 1/2}){sub 4} tetrahedral unit structure (Q{sub 2}, Q{sub 3} and Q{sub 4}) are clearly resolved in the silica aerogel samples. The calcining process and the loading of metal compounds produce line broadening in the {sup 29}Si spectra sufficient to prevent clear resolution of the three distinct Q{sub n} spectral lines, but the broadened spectra indicate that the three Q sub-unit structures are still present. The ferrocene and ruthenocene molecules used in the vapor phase deposition method exhibit a rapid exchange within the silica aerogel support similar to what one would expect in the gas or liquid state. (author)

  10. Support effect on carbon nanotube growth by methane chemical vapor deposition on cobalt catalysts

    International Nuclear Information System (INIS)

    The influence of the support on carbon nanotube production by methane chemical vapor deposition (CVD) on cobalt catalysts was investigated. N2 physisorption, X-ray diffractometry (XRD), temperature programmed reduction (TPR) and H2 and CO chemisorption techniques were used to characterize the structure of cobalt catalysts supported on different metal oxides (Al2O3, SiO2, Nb2O5 and TiO2). Raman spectroscopy, temperature programmed oxidation (TPO) and scanning electron microscopy (SEM) were used for the characterization and quantification of produced carbon species. On carbon nanotube growth, the catalyst produced three main carbon species: amorphous carbon, single walled carbon nanotubes (SWNT) and multi walled carbon nanotubes (MWNT). The characterization techniques showed that the catalyst selectivity to each kind of nanotube depended on the cobalt particle size distribution, which was influenced by the textural properties of the support. Co/TiO2 showed the highest selectivity towards single wall nanotube formation. This high selectivity results from the narrow size distribution of cobalt particles on TiO2. (author)

  11. Gold-supported cerium-doped NiOx catalysts for water oxidation

    Science.gov (United States)

    Ng, Jia Wei Desmond; García-Melchor, Max; Bajdich, Michal; Chakthranont, Pongkarn; Kirk, Charlotte; Vojvodic, Aleksandra; Jaramillo, Thomas F.

    2016-05-01

    The development of high-performance catalysts for the oxygen-evolution reaction (OER) is paramount for cost-effective conversion of renewable electricity to fuels and chemicals. Here we report the significant enhancement of the OER activity of electrodeposited NiOx films resulting from the combined effects of using cerium as a dopant and gold as a metal support. This NiCeOx–Au catalyst delivers high OER activity in alkaline media, and is among the most active OER electrocatalysts yet reported. On the basis of experimental observations and theoretical modelling, we ascribe the activity to a combination of electronic, geometric and support effects, where highly active under-coordinated sites at the oxide support interface are modified by the local chemical binding environment and by doping the host Ni oxide with Ce. The NiCeOx–Au catalyst is further demonstrated in a device context by pairing it with a nickel–molybdenum hydrogen evolution catalyst in a water electrolyser, which delivers 50 mA consistently at 1.5 V over 24 h of continuous operation.

  12. 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.

  13. 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.

  14. Thermally Activated Palm Kernel Based Carbon as a Support for Edible Oil Hydrogenation Catalyst

    Directory of Open Access Journals (Sweden)

    Abdulmajid Alshaibani

    2013-01-01

    Full Text Available Activated carbon has distinctive properties as a support for hydrogenation catalysts. Thermally activated carbon has been prepared from palm kernel shell at 1073 K and placed under nitrogen flow for 2 h. It was impregnated by palladium using toluene solution of Pd (acac2. The Pd/C was reduced using a water solution of potassium borohydride (KBH4. The Pd-B/C was characterized by the Brunauer-Emmett-Teller surface area analysis (BET, scanning electron microscopy (SEM, transmission electron microscopy (TEM and inductively-coupled plasma mass spectrometry (ICP-MS. Pd-B/C was applied for sunflower oil hydrogenation at a temperature of 373 K, hydrogen pressure of 413.5 kPa and agitation of 1400 rpm for 1 h. Pd-B/C noticeably exhibited a higher overall catalyst activity in comparison to some recently published palladium catalysts.

  15. 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.

  16. 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

    2016-02-01

    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.

  17. 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.

  18. Kinetics studies of d-glucose hydrogenation over activated charcoal supported platinum catalyst

    Science.gov (United States)

    Ahmed, Muthanna J.

    2012-02-01

    The kinetics of the catalytic hydrogenation of d-glucose to produce d-sorbitol was studied in a three-phase laboratory scale reactor. The hydrogenation reactions were performed on activated charcoal supported platinum catalyst in the temperature range 25-65°C and in a constant pressure of 1 atm. The kinetic data were modeled by zero, first and second-order reaction equations. In the operating regimes studied, the results show that the hydrogenation reaction was of a first order with respect to d-glucose concentration. Also the activation energy of the reaction was determined, and found to be 12.33 kJ mole-1. A set of experiment was carried out to test the deactivation of the catalyst, and the results show that the deactivation is slow with the ability of using the catalyst for several times with a small decrease in product yield.

  19. Preparation and characterization of alumina-supported Co and Ag/Co catalysts

    Directory of Open Access Journals (Sweden)

    Marina Simionato

    2003-12-01

    Full Text Available The effect of silver addition as a promoter in alumina supported cobalt oxide catalysts is investigated in this study. The Co/Al2O3 and Ag/Co/Al2O3 catalysts were prepared by incipient wetness impregnation. The catalysts were characterized by inductively-coupled plasma spectrometry, X-ray diffraction (XRD, temperature programmed reduction with hydrogen (TPR-H2, Raman spectroscopy and nitrogen adsorption at 77 K. XDR and Raman Spectroscopy results indicated the presence of Co3O4 species. The peaks observed in the TPR-H2 patterns were attributed to the reduction of Ag2O, Co3O4 crystallites and Co+3, Co+2 species interacting with alumina. It is suggested that silver used as a promoter favors the reduction of cobalt, facilitating the formation of active Co0 sites.

  20. Effect of Activated Carbon as a Support on Metal Dispersion and Activity of Ruthenium Catalyst for Ammonia Synthesis

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Ten kinds of activated carbon from different raw materials were used as supports to prepare ruthenium catalysts. N2 physisorption and CO chemisorption were carried out to investigate the pore size distribution and the ruthenium dispersion of the catalysts. It was found that the Ru dispersion of the catalyst was closely related to not only the texture of carbon support but also the purity of activated carbon. The activities of a series of the carbon-supported barium-promoted Ru catalysts for ammonia synthesis were measured at 425 ℃, 10.0 MPa and 10 000 h-1. The result shows that the same raw material activated carbon, with a high purity, high surface area, large pore volume and reasonable pore size distribution might disperse ruthenium and promoter sufficiently, which activated carbon as support, could be used to manufacture ruthenium catalyst with a high activity for ammonia synthesis. The different raw material activated carbon as the support would greatly influence the catalytic properties of the ruthenium catalyst for ammonia synthesis. For example, with coconut shell carbon(AC1) as the support, the ammonia concentration in the effluent was 13.17% over 4%Ru-BaO/AC1 catalyst, while with the desulfurized coal carbon(AC10) as the support, that in the effluent was only 1.37% over 4%Ru-BaO/AC10 catalyst.

  1. Low Temperature Activation of Supported Metathesis Catalysts by Organosilicon Reducing Agents.

    Science.gov (United States)

    Mougel, Victor; Chan, Ka-Wing; Siddiqi, Georges; Kawakita, Kento; Nagae, Haruki; Tsurugi, Hayato; Mashima, Kazushi; Safonova, Olga; Copéret, Christophe

    2016-08-24

    Alkene metathesis is a widely and increasingly used reaction in academia and industry because of its efficiency in terms of atom economy and its wide applicability. This reaction is notably responsible for the production of several million tons of propene annually. Such industrial processes rely on inexpensive silica-supported tungsten oxide catalysts, which operate at high temperatures (>350 °C), in contrast with the mild room temperature reaction conditions typically used with the corresponding molecular alkene metathesis homogeneous catalysts. This large difference in the temperature requirements is generally thought to arise from the difficulty in generating active sites (carbenes or metallacyclobutanes) in the classical metal oxide catalysts and prevents broader applicability, notably with functionalized substrates. We report here a low temperature activation process of well-defined metal oxo surface species using organosilicon reductants, which generate a large amount of active species at only 70 °C (0.6 active sites/W). This high activity at low temperature broadens the scope of these catalysts to functionalized substrates. This activation process can also be applied to classical industrial catalysts. We provide evidence for the formation of a metallacyclopentane intermediate and propose how the active species are formed. PMID:27610418

  2. Study of Carbon Nanotube Supported Co-Mo Selective Hydrodesulphurization Catalysts for Fluid Catalytic Cracking Gasoline

    Institute of Scientific and Technical Information of China (English)

    Wenkui Yin; Mei Li; Hongyan Shang; Chenguang Liu; Fei Wei

    2005-01-01

    In this paper,carbon nanotube supported Co-Mo catalysts for selective hydrodesulphurization (HDS) of fluid catalytic cracking (FCC) gasoline were studied,using di-isobutylene,cyclohexene,1-octene and thiophene as model compounds to simulate FCC gasoline. The results show that the Co-Mo/CNT has very high HDS activity and HDS/hydrogenation selectivity comparing with the Co-Mo/γ-Al2O3 and Co-Mo/AC catalyst systems. The saturation ratio of cyclohexene was lower than 50%,and the saturation ratio of 1,3-di-isobutylene lower than 60% for the Co-Mo/CNT catalysts. Co/Mo atomic ratio was found to be one of the most important key factors in influencing the hydrogenation selectivity and HDS activity,and the most suitable Co/Mo atomic ratio was 0.4. Co/CNT and Mo/CNT mono-metallic catalysts showed lower HDS activity and selectivity than the Co-Mo/CNT bi-metallic catalysts.

  3. n-Butane Oxidation over γ-Al2O3 Supported Vanadium Phosphate Catalysts

    Institute of Scientific and Technical Information of China (English)

    Y.H.Taufiq-Yap; L.K.Leong; R.Irmawati

    2007-01-01

    Four vanadium phosphate catalysts supported on γ-Al2O3(20 wt%)were synthesized via 75 h)at 673 K in a reaction flow of n-butane/air mixture.The samples calcined for 6 and 10 h produced only a single phase of(VO)2P2O7.However,the VOPO4 phase(β-VOPO4)was detected and became more prominent with only a minor pyrophosphate peaks were found after 30 h of calcination.All these pyrophosphate peaks disappeared after 75 h of calcination.The formation of V5+ phase Was also observed in the SEM micrographs.The redox properties and the nature of oxidants of the catalysts employed in this study were investigated by H2-TPR analysis.Selective oxidation of n-butane to maleic anhydride (MA) over these catalysts shows that the percentage of n-butane conversion decreases with the transformation of the catalysts from V4+ to V5+ phases.An appropriate ratio of V5+/V4+ can enhance the performance of the VPO catalyst.However,a higher amount of V5+ and its associated oxygen species are responsible to promote the MA selectivity.

  4. Direct synthesis of dimethyl carbonate over rare earth oxide supported catalyst

    Institute of Scientific and Technical Information of China (English)

    JIANG Qi; CHENG Jiye; GAO Zhiqin

    2007-01-01

    Solid base catalysts for the direct synthesis of dimethyl carbonate (DMC)from carbon dioxide,methanol,and propylene oxide were prepared by loading KCl and K2CO3 on the surface of La2O3,Y2O31,CeO2 and Nd2O3.The catalysts were characterized by thermogravimetric analysis (TGA) and X-ray diffraction(XRD) techniques.The catalytic activities were efficiently influenced by the preparation conditions.The optimal loading amount of K2CO3 is 17.6%(mass)for KCl-K2CO3/Y2O3 and 22.2%for other catalysts.Supports affected the activity of catalyst.KCl-K2CO3/Nd2O3 exhibited the highest activity.The activity of KCl-K2CO3/Y2O3 increased wilh the increase of Calcination temperature in the range of 800℃-900℃.The formation of KYO2 Y3O4Cl or YOx species probably promoted the catalysts.

  5. The Stereoselective Epoxidation by a New Type of Soluble Polymer-Supported Catalysts

    Institute of Scientific and Technical Information of China (English)

    Wang Yongmei; Wang Xin; Liu Juyan

    2004-01-01

    As the phase transfer catalyst (PTC) is one of most important catalysts in organic synthesis. Here, we represent initial results of a research program aimed at the rational design of a variety of new two centers, soluble polyethylene glycol (PEG) supported catalysts based on the cinchona alkaloid system and their application in asymmetric expoxidation process.Table 1 and Table 2 summarized the results of epoxidation of substituted chalcone As shown in Table 1 and Table 2, chalcone derivatives as reactive olefins afforded the corresponding epoxided with modest to good enantiomeric excesses. In contrast, a definite trend to higher ee value is displayed by solvent effect. It was found that enantioselectivity becomes higher with the polarity increases(Table 1, Table 2). Changing catalyst 1 to catalyst 2, ee value was increased (entry 6 in Table 1) as well. Compared with Me, NO2 groups, substitution on the aromatic ring of the enone carbonyl function by OMe group increased the enantioselectivity(entry 3 in Table 1 and entry 3' in Table 2).

  6. 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 S.; Hensley, Alyssa; 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.

  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. Research of special carbon nanobeads supported Pt catalyst for fuel cell through high temperature pyrolysis and deposition from novel phthalocyanine

    Institute of Scientific and Technical Information of China (English)

    GUO Yanchuan; YUE Jun; PAN Zhongxiao; XU Haitao; ZHANG Bing; HAN Fengmei; CHEN Lijuan; PENG Bixian; XIE Wenwei; QIAN Haisheng; YAN Tiantang

    2004-01-01

    The carbon nanobeads were prepared through high temperature pyrolysis and deposition from phthaiocyanine. After surface's functionalization treatment of the carbon beads, the carbon nanobeads supported Pt catalyst was produced. The Pt/C catalyst was characterized by SEM,TEM, Raman spectrum, EDS and XRD methods. Combining the carbonaceous paper spreaded up with the catalyst with Nafion membrane, we made MEA electrode. The discharge curves indicated that this carbon nanobeads supported Pt is a good fuel cell catalyst with excellent performance, high activity and sign of a long-time life.

  9. XPS Characterization of Carbon Nanotube Supported CoMo Hydrodesulfurization Catalysts

    Institute of Scientific and Technical Information of China (English)

    SHANG, Hong-Yan(商红岩); LIU, Chen-Guang(刘晨光); ZHAO, Rui-Yu(赵瑞玉); WU, Ming-Bo(吴明铂); WEI, Fei(魏飞)

    2004-01-01

    In this paper, the effect of catalytic support and sulfiding method on the chemical state of supported Co-Mo catalysts is studied by XPS. After sulfidation with in-situ method, the majority of molybdenum in CNT supported CoMo catalyst is transferred to a species with a formal chemical state Mo(Ⅳ) in MoS2 phase, and the rest to Mo(Ⅴ)which consists of Mo coordinated both to O and S, such as MoO2S22- and MoO3S2-. In case of CoMo/γ-Al2O3 catalyst sulfided with in-situ method, a fraction of molybdenum is transferred to formal state Mo(Ⅳ) in the form of MoS2, but there is still a mount of unreduced Mo(Ⅵ) phase which is difficult to be sulfided. In CoMo/CNT catalytic system sulfided with ex-situ method, Mo(Ⅳ) in the form of MoS2 is detected along with a portion of unreduced Mo(Ⅵ) phase, suggesting that not all the Mo phases are reduced and sulfided by ex-situ method. As for CoMo/γ-Al2O3, a portion of molybdenum is sulfided to intermediate reduced state Mo(Ⅴ) which consists of Mo coordinated both to O and S, such as MoO2S22- and MoO3S2-, in addition, there is still a fraction of unreduced Mo(Ⅵ)phase. XPS analyses results suggest that CNT support facilitates the reduction and sulfidation of active species to a large extent, and that alumina support strongly interacts with active species, hereby producing a fraction of phase which resists complete sulfiding. Catalytic measurements of catalysts in the HDS of dibenzothiophene (DBT) show that CoMo/CNT catalysts are of higher HDS activity and selectivity than CoMo/γ-Al2O3 catalyst, which is in good relation with the sulfiding behavior of the corresponding catalyst.

  10. Pt and Pd supported on glass fibers as effective combustion catalysts

    OpenAIRE

    Kiwi-Minsker, L.; Yuranov, I.; Slavinskaia, E.; Zaikovskii, V.; Renken, A.

    2000-01-01

    Pd and Pt supported on glass fiber materials with developed porosity and high sp. surface areas were studied in total propane oxidn. The reaction was carried out in recycling reactor and the kinetic parameters were detd. under different reaction conditions in the temp. range 200-500 DegC. Pt catalysts were seen to be more active than Pd for the same metal loading on identical support. Catalytic activity was seen to depend on support compn. The highest activity was obsd. on Pt supported on gla...

  11. 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

    2016-03-29

    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.

  12. 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

    2016-03-01

    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.

  13. Hydrogenation of aniline on a low-percentage, supported rhodium catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Ualikhanova, A.; Temirbulatova, A.E.

    1992-01-10

    The products of hydrogenation of aniline and their derivatives exhibit biological activity and are used in the pharmaceutical industry for preparation of analgesic, antipyretic, and sulfanilamide drugs. Up to 30% of the total consumption of aniline is for synthesis of drugs. Hydrogenation of aniline on platinum metals supported on carbon was studied by Rylander et al. The authors investigated the catalytic properties of rhodium supported on oxides in saturation of aniline with hydrogen in water. In most cases, the amount of noble metal in the supported catalyst was 5%. Decreasing the concentration of active phase in the catalyst is economically advantageous. The features of hydrogenation of aniline in the presence of 1% Rh/MgO in solutions with wide variation of the technological parameters of the process were investigated in the present study. 19 refs., 3 figs., 2 tabs.

  14. PREPARATION OF NOVEL POLYETHYLENE-graft- POLY(4-VINYLPYRIDINE)-SUPPORTED METALLOCENE CATALYSTS FOR ETHYLENE POLYMERIZATION

    Institute of Scientific and Technical Information of China (English)

    Ning Zhu; Yong Chen; Zi-long Li; Yuan-xia Liu; Yu-cai Ke; Wen-Hua Sun

    2003-01-01

    Polyethylene (PE) grafting 4-vinylpyridine copolymers has been produced as powders of different rushes by the irradiation method. After treatment with methylaluminoxane (MAO), the copolymers were used as supports for Cp2ZrCl2 catalyst. Results of X-ray photoelectron spectroscopy, Fourier transforms infrared spectroscopy, ultraviolet spectroscopy and scanning electron microscope measurements show that the catalytic sites have been linked through MAO on the PE-graft-4-vinylpyridine (PEVP). The percentages of grafting 4-vinylpyridine and supported Cp2ZrCl2 depend on the size of polyethylene powder. The smaller the polyethylene powder, the more percent of 4-vinylpyridine groups and Cp2ZrCl2 exist on the polyethylene chains, and the PEVP-supported catalyst has a relatively high activity for ethylene polymerization.

  15. Characterization of supported TiO{sub 2}-based catalysts green-prepared and employed for photodegradation of malodorous DMDS

    Energy Technology Data Exchange (ETDEWEB)

    Chuang, Li-Chin [Department of Hair Styling and Design, Hungkuang University, 1018 Sec. 6 Taiwan Boulevard, Shalu, Taichung 43302, Taiwan (China); Luo, Chin-Hsiang, E-mail: andyluo@hk.edu.tw [Department of Safety, Health and Environmental Engineering, Hungkuang University, 1018 Sec. 6 Taiwan Boulevard, Shalu, Taichung 43302, Taiwan (China)

    2013-02-15

    Graphical abstract: Display Omitted Highlights: ► We prepare rutile-TiO{sub 2} based catalysts using a simple and eco-efficient method. ► TiO{sub 2} based catalysts coated on supporting materials have large BET surface areas. ► Supported TiO{sub 2} based catalysts efficiently degrade malodorous DMDS. -- Abstract: Titanium dioxide (TiO{sub 2})-based catalysts coated onto two supporting materials (Pyrex glass beads and porous polypropylene fibers) in laboratory have been prepared and characterized. A modified preparation process at low temperature involving the addition of distilled water, aqueous ammonia, and ferrous sulfate, respectively, was used to enhance the spontaneous precipitation of three TiO{sub 2}-based catalysts. The Brunauer–Emmett–Teller surface area of three catalysts was ranged from 160.1 to 202.7 m{sup 2}/g. The surface morphology of three catalysts was identified by a scanning electron microscopy equipped with an X-ray energy dispersive spectrometer. The photocatalytic degradation of dimethyldisulfide was investigated using the supported TiO{sub 2}-based catalysts. The original dimethyldisulfide almost was degraded within 2 h. A similar photocatalytic activity on degrading dimethyldisulfide was demonstrated in comparison with commercial catalysts. Simplicity, low cost, low energy consumption, and solvent-free are the advantages of this proposed method which can be used to photodecompose environmental organic pollutants effectively without heat treatment.

  16. Preparation of catalyst for a polymer electrolyte fuel cell using a novel spherical carbon support

    Energy Technology Data Exchange (ETDEWEB)

    Eguchi, Mika; Okubo, Atsuhiko; Kobayashi, Yoshio [Department of Biomolecular Functional Engineering, Faculty of Engineering, Ibaraki University, 4-12-1, Nakanarusawa, Hitachi, Ibaraki 316-8511 (Japan); Yamamoto, Shun [Material and Biological Sciences, Graduate School of Science and Engineering, Faculty of Engineering, Ibaraki University, 4-12-1, Nakanarusawa, Hitachi, Ibaraki 316-8511 (Japan); Kikuchi, Mayuko; Nishitani-Gamo, Mikka [Department of Applied Chemistry, Faculty of Engineering, Toyo University, 2100 Kujirai, Kawagoe, Saitama 350-8585 (Japan); Uno, Katsuhiro [Department of Media and Telecommunications Engineering, Faculty of Engineering, Ibaraki University, 4-12-1, Nakanarusawa, Hitachi, Ibaraki 316-8511 (Japan); Ando, Toshihiro [National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan)

    2010-09-15

    In this study, the support Pt catalyst was supported by a novel spherical carbon using a convenient technique. Two different preparation methods utilizing a nanocolloidal solution method without heat treatment were developed (methods 1 and 2). The scanning electron microscope (SEM) and transmission electron microscope (TEM) observations showed that the Pt nanoparticles (particle size) were supported, with higher dispersion being achieved with method 2 than method 1. The peak of the Pt metal was confirmed from the X-ray diffraction (XRD) measurement. Based on the inductively coupled plasma mass spectrometry (ICP-MS) measurements, Pt loading was 19.5 wt.% in method 1 and approximately 50 wt.% in method 2. The Pt specific surface area of the Pt/novel spherical carbon catalyst calculated from the cyclic voltammetry (CV) measurement result was larger than that of the commercially available Pt/Ketjen catalyst. These results indicated that the Pt nanoparticles were supported in high dispersion without heat treatment using novel spherical carbon as a carbon support. (author)

  17. 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.

  18. MCM-41 Bound Ruthenium Complex as Heterogeneous Catalyst for Hydrogenation Ⅰ: Effect of Support, Ligand and Solvent on the Catalyst Performance

    Institute of Scientific and Technical Information of China (English)

    YU, Ying-Min; FEI, Jin-Hua; ZHANG, Yi-Ping; ZHENG, Xiao-Ming

    2006-01-01

    The functionalized MCM-41 mesoporous bound ruthenium complex was synthesized and characterized using elemental analysis, atomic absorption spectrophotometer, BET, XRD and FTIR. Hydrogenation of carbon dioxide to formic acid was investigated over these catalysts under supercritical CO2 condition. The effect of reactant gas partial pressure, supports, solvents and ligands on the synthesis of formic acid was studied. These factors could influence the catalyst activity, stability and reuse performance greatly and no byproduct was detected. These promising catalysts also offered the industrial advantages such as easy separation.

  19. Use of heterogeneous CaO and SnO2 catalysts supported on rice husk ash to produce biodiesel

    International Nuclear Information System (INIS)

    Silica obtained from rice husk after acid leaching and calcination was compared to commercial silica as a catalyst support. CaO and SnO2 catalysts were prepared by impregnation and tested in the transesterification of soybean oil and the esterification of oleic acid. CaO catalysts showed basic character and were the most active for transesterification, whereas SnO2 catalysts were acid and the most effective for esterification. In both cases the performances of the catalysts prepared with rice husk ash and commercial silica were similar. These results demonstrate that rice husk is a cost-effective and environmentally-friendly source of silica that can be used as a catalyst support. (author)

  20. 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. PMID:26373150

  1. Carbon-Supported Silver Catalysts for CO Selective Oxidation in Excess Hydrogen

    Institute of Scientific and Technical Information of China (English)

    Limin Chen; Ding Ma; Barbara Pietruszka; Xinhe Bao

    2006-01-01

    Carbon materials were used as supports for Ag catalysts that are prepared using the conventional wet impregnation method, and their catalytic properties for CO selective oxidation in excess hydrogen at temperatures below 483 K were tested. A variety of techniques, e.g. N2 adsorption, XPS, TPD, UV-Vis DRS, TEM and SEM, were used to determine the influence of physical and chemical properties of the carbon on the properties of Ag catalyst. It was found that defects on the carbon surface served as nucleation sites for silver ions, while functional groups on carbon surface induced their reduction to the metallic form. The formation of silver particles on carbon was governed by homogeneous and/or heterogeneous nucleation during the impregnation and subsequent activation processes. The best catalytic performance was obtained with a Ag/carbon black catalyst with a uniform size distribution of silver nanoparticles (about 12 nm), moderate BET surface area (with a mesoporous structure), and a limited amount of carbon-oxygen groups. The research indicates that carbon materials are potentially good supports for silver catalysts for preferential oxidation of CO in excess hydrogen.

  2. Transition metal-modified polyoxometalates supported on carbon as catalyst in 2-(methylthio)-benzothiazole sulfoxidation

    Indian Academy of Sciences (India)

    Romina A Frenzel; Gustavo P Romanelli; Mirta N Blanco; Luis R Piz

    2015-01-01

    Polyoxometalates with lacunary Keggin structure modified with transition metal ions [PW11O39M(H2O)]5−, where M = Ni2+, Co2+, Cu2+ or Zn2+, were synthesized and supported on activated carbon to obtain the PW11MC catalysts. Using FT-IR and DTA-TGA it was concluded that the [PW11O39M(H2O)]5− species are interacting with the functional groups of the support, and that thermal treatment leads to the loss of the coordinatively bonded water molecules without any noticeable anion degradation. The activity and selectivity of the catalysts in the sulfoxidation reaction of 2-(methylthio)-benzothiazole, an emerging environmental pollutant, were evaluated. The reaction was carried out in acetonitrile as solvent using H2O2 35% p/v as a clean oxidant. The conversion values decreased in the following order: PW11NiC > PW11CuC > PW11CoC > PW11ZnC, with selectivity to sulfoxide higher than 69%. The catalyst could be reused without appreciable loss of the catalytic activity at least three times. The materials were found to be efficient and recyclable catalysts for 2-(methylthio)-benzothiazole sulfoxidation in order to obtain a more biodegradable product than the corresponding substrate.

  3. Liquid Phase Hydrogenation of Benzalacetophenone:Effect of Solvent,Catalyst Support,Catalytic Metal and Reaction Conditions%Liquid Phase Hydrogenation of Benzalacetophenone: Effect of Solvent, Catalyst Support, Catalytic Metal and Reaction Conditions

    Institute of Scientific and Technical Information of China (English)

    Achim STOLLE; Christine SCHMOGER; Bernd ONDRUSCHKA; Werner BONRATH; Thomas F. KELLER; Klaus D. JANDT

    2011-01-01

    Innovative catalysts based on a “porous glass” support material were developed and investigated for the reduction of benzalacetophenone.The easy preparation conditions and possibility to use different metals (e.g.Pd,Pt,Rh) for impregnation gave a broad variety of these catalysts.Hydrogenation experiments with these supported catalysts were carried out under different hydrogen pressures and temperatures.Porous glass catalysts with Pd as the active component gave chemoselective hydrogenation of benzalacetophenone,while Pt- and Rh-catalysts tended to further reduce the carbonyl group,especially at elevated hydrogen pressures and temperatures.Kinetic analysis of the reactions revealed these had zero order kinetics,which was independent of the type of porous glass support and solvent used.

  4. Alcohol Synthesis over Pre-Reduced Activated Carbon-Supported Molybdenum-Based Catalysts

    Directory of Open Access Journals (Sweden)

    Edwin L. Kugler

    2003-01-01

    Full Text Available Activated carbon (AC-supported molybdenum catalysts, either with or without a potassium promoter, were prepared by the incipient wetness impregnation method. The materials were characterized using differential thermal analysis (DTA and temperature programmed reduction (TPR, and were used for mixed alcohol synthesis from syngas (CO+H2. DTA results showed that a new phase, related to the interaction between Mo species and the AC support, is formed during the calcination of the Mo/AC catalyst, and the introduction of a K promoter has noticeable effect on the interaction. TPR results indicated that the Mo is more difficult to reduce after being placed onto the AC support, and the addition of a K promoter greatly promotes the formation of Mo species reducible at relatively low temperatures, while it retards the generation of Mo species that are reducible only at higher temperatures. These differences in the reduction behavior of the catalysts are atributed to the interaction between the active components (Mo and K and the support. Potassium-doping significantly promotes the formation of alcohols at the expense of CO conversion, especially to hydrocarbons. It is postulated that Mo species with intermediate valence values (averaged around +3.5 are more likely to be the active phase(s for alcohol synthesis from CO hydrogenation, while those with lower Mo valences are probably responsible for the production of hydrocarbons.

  5. Gold-Iron Oxide Catalyst for CO Oxidation: Effect of Support Structure

    Directory of Open Access Journals (Sweden)

    Hui-Zhen Cui

    2016-03-01

    Full Text Available Gold-iron oxide (Au/FeOx is one of the highly active catalysts for CO oxidation, and is also a typical system for the study of the chemistry of gold catalysis. In this work, two different types of iron oxide supports, i.e., hydroxylated (Fe_OH and dehydrated iron oxide (Fe_O, have been used for the deposition of gold via a deposition-precipitation (DP method. The structure of iron oxide has been tuned by either selecting precipitated pH of 6.7–11.2 for Fe_OH or changing calcination temperature of from 200 to 600 °C for Fe_O. Then, 1 wt. % Au catalysts on these iron oxide supports were measured for low-temperature CO oxidation reaction. Both fresh and used samples have been characterized by multiple techniques including transmission electron microscopy (TEM and high-resolution TEM (HRTEM, X-ray diffraction (XRD, X-ray photoelectron spectroscopy (XPS, X-ray absorption near edge structure (XANES and temperature-programmed reduction by hydrogen (H2-TPR. It has been demonstrated that the surface properties of the iron oxide support, as well as the metal-support interaction, plays crucial roles on the performance of Au/FeOx catalysts in CO oxidation.

  6. Direct fabrication of Pt-supported porous carbon catalyst for fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, D.Y.; Wang, G.; Konstantinov, K. [Wollongong Univ., NSW (Australia). Inst. for Superconducting and Electronic Materials; Ma, Z.F.; Liub, H.K. [Shanghai Jiaotong Univ., Shanghai (China). Dept. of Chemical Engineering

    2006-07-01

    Platinum (Pt) based electrocatalysts are generally used in proton exchange membrane fuel cells (PEMFC) and in direct alcohol fuel cells (DAFC) operating at relatively low temperature. Wet impregnation techniques and chemical reduction of the metal precursors are the conventional preparation methods for these electrocatalysts. These conventional synthesis methods are based on impregnation-reduction, microemulsions, sonochemistry, and microwave irradiation. However, Pt-supported carbon catalysts cannot be prepared by such methods due to the very long time needed for the synthesis of carbon. In addition, post-fabrication steps must be taken, such as surface modification of carbon and metal supporting. For these reasons, this study presented a new fabrication method for producing Pt-carbon catalysts directly by a Pt-embedded template. The new method provides a time saving route for the preparation of a Pt catalyst supported on a mesoporous carbon. In this study, Pt-supported porous carbon was prepared using the carbon xerogel method. In particular, a platinum salt was dissolved in an aqueous solution of carbon xerogel precursor and reduced under 5 per cent hydrogen/argon gas along with carbonization. Images from a scanning electron microscope revealed that the nanoscale particle structure of the Pt-embedded carbon electrocatalyst had homogeneously distributed bright particles, likely attributed to Pt. 10 refs.

  7. 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....

  8. Gold/Iron Carbonyl Clusters for Tailored Au/FeOx Supported Catalysts

    Directory of Open Access Journals (Sweden)

    Stefania Albonetti

    2011-12-01

    Full Text Available A novel preparation method was developed for the preparation of gold/iron oxide supported catalysts using the bimetallic carbonyl cluster salts [NEt4]4[Au4Fe4(CO16] and [NEt4][AuFe4(CO16] as precursors of highly dispersed nanoparticles over different supports. A series of catalysts with different metal loadings were prepared and tested in the complete oxidation of dichlorobenzene, toluene, methanol and in the preferential oxidation of CO in the presence of H2 (PROX as model reactions. The characterization by BET, XRD, TEM, H2-TPR, ICP-AES and XPS point out the way the nature of the precursors and the thermal treatment conditions affected the dispersion of the active phase and their catalytic activity in the studied reactions.

  9. Preparation of microcapsule-supported palladium catalyst using SPG (Shirasu Porous Glass) emulsification technique

    Institute of Scientific and Technical Information of China (English)

    Ying Liu; Xiu Juan Feng; De Cai Bao; Kai Xiao Li; Ming Bao

    2010-01-01

    A new method for the preparation of microcapsule-supported palladium catalyst was described.The highly monodisperse crosslinked polystyrene microcapsules containing phosphine ligand were synthesized by the self-assembling of phase separated polymer(SaPSeP)method using diphenyl(4-vinylphenyl)phosphine and divinylbenzene as a monomer and crosslinking agent,respectively,and 2,2'-azobisisobutyronitrile(AIBN)as an initiator within the droplets of oil-in-water(O/W)emulsions,which were prepared by using the Shirasu Porous Glass(SPG)membrane emulsification technique.The prepared microcapsule-supported palladium catalyst exhibited high catalytic activity for Heck reaction and can be reused several times without loss of activity.

  10. Imidazolium ionic liquid-supported sulfonic acids: Efficient and recyclable catalysts for esterification of benzoic acid

    Institute of Scientific and Technical Information of China (English)

    Yue Qin Cai; Guo Qiang Yu; Chuan Duo Liu; Yuan Yuan Xu; Wei Wang

    2012-01-01

    Several imidazolium ionic liquid (IL)-supported sulfonic acids with different anions,[C3SO3Hmim]HSO4,[C3SO3Hmim]BF4,[C3SO3Hmim]PF6,and [C3SO3Hmim]CF3SO3,were synthesized and applied as catalysts for esterification reaction of benzoic acid.The experimental results indicate that imidazolium IL-supported sulfonic acid containing anion of HSO4- shows the best catalytic activity.Only when less [C3SO3Hmim]HSO4 (0.3 equiv.) applied,was the product obtained with high yield of 97%.Furthermore,the produced esters could be separated by decantation,and the catalyst could be reused after the removal of water.

  11. 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

  12. Ni catalysts supported on nanocrystalline magnesium oxide for syngas production by CO2 reforming of CH4

    Institute of Scientific and Technical Information of China (English)

    Fereshteh Meshkani; Mehran Rezaei

    2011-01-01

    CO2 reforming of methane(CDRM)was carried out over MgO supported Ni catalysts with various Ni loadings.The preparation of MgO supported Ni catalysts via surfactant-assisted precipitation method led to the formation of a nanocrystalline carrier for nickel catalysts.The synthesized samples were characterized by XRD,N2 adsorption-desorption,H2 chemisorption,TPR,TPO and SEM techniques.It was found that the high catalytic activity and stability of the prepared catalysts could be attributable to high dispersion of reduced Ni species and basicity of support surface.In addition,the effect of feed ratio,nickel loading and GHSV on the catalytic performance of CDRM over the catalysts were investigated.

  13. 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.

    2001-01-01

    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

  14. Rice Husk Supported Catalysts for Degradation of Chlorobenzenes in Capillary Microreactor

    OpenAIRE

    Abdulelah Thabet; Chanbasha Basheer; Than Htun Maung; Hasan Ali Al-Muallem; Abdul Nasar Kalanthoden

    2015-01-01

    Chlorinated organic pollutants are persistent, toxic, and ubiquitously distributed environmental contaminants. These compounds are highly bioaccumulative and adversely affect the ozone layer in the atmosphere. As such, their widespread usage is a major cause of environmental and health concern. Therefore, it is important to detoxify such compounds by environment friendly methods. In this work, rice husk supported platinum (RHA-Pt) and titanium (RHA-Ti) catalysts were used, for the first time,...

  15. Ceria catalyst for inert-substrate-supported tubular solid oxide fuel cells running on methane fuel

    Science.gov (United States)

    Zhao, Kai; Kim, Bok-Hee; Du, Yanhai; Xu, Qing; Ahn, Byung-Guk

    2016-05-01

    A ceria catalyst is applied to an inert-substrate supported tubular single cell for direct operation on methane fuel. The tubular single cell comprises a porous yttria-stabilized zirconia (YSZ) supporter, a Ni-Ce0.8Sm0.2O1.9 anode, a YSZ/Ce0.8Sm0.2O1.9 bi-layer electrolyte, and a La0.6Sr0.4Co0.2Fe0.8O3-δ cathode. The ceria catalyst is incorporated into the porous YSZ supporter layer by a cerium nitrate impregnation. The effects of ceria on the microstructure and electrochemical performance of the tubular single cell are investigated with respect to the number of impregnations. The optimum number of impregnations is determined to be four based on the maximum power density and polarization property of the tubular single cell in hydrogen and methane fuels. At 700 °C, the tubular single cell shows similar maximum power densities of ∼260 mW cm-2 in hydrogen and methane fuels, respectively. Moreover, the ceria catalyst significantly improves the performance stability of the cell running on methane fuel. At a current density of 350 mA cm-2, the single cell shows a low degradation rate of 2.5 mV h-1 during the 13 h test in methane fuel. These results suggest the feasibility of applying the ceria catalyst to the inert-substrate supported tubular single cell for direct operation on methane fuel.

  16. Polymer Supported Heterogenous Catalysts for Direct Synthesis of Hydrogen Peroxide in Absence of Selectivity Enhancers

    OpenAIRE

    Sterchele, Stefano

    2013-01-01

    The research program developed during the Ph.D. School is focused on the study of metal catalysts supported on cross-linked functional polymers (CFPs) for the direct synthesis of hydrogen peroxide. In the last twenty years this compound has become a commodity with a constant increasing demand because of its strong oxidant properties and the formation of water as the reduction byproduct. In particular, H2O2 is widely employed as environmentally-friendly bleaching and cleaning agent. The...

  17. 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 cond...... conditions; the reactions can be performed in an open flask and at room temperature. Benzaldehyde is even oxidised at a reasonable rate below -70 degrees C. Acrolein is oxidised to methyl acrylate in high yield using the same protocol....

  18. Carbon/H-ZSM-5 composites as supports for bi-functional Fischer-Tropsch synthesis catalysts

    NARCIS (Netherlands)

    Valero-Romero, M.J.; Sartipi, S.; Sun, X.; Rodríguez-Mirasol, J.; Cordero, T.; Kapteijn, F.; Gascon, J.

    2016-01-01

    Mesoporous H-ZSM-5–carbon composites, prepared via tetrapropylammonium hydroxide (TPAOH) post treatment of H-ZSM-5 followed by deposition of pyrolytic carbon, have been used as the support for the preparation of Co-based Fischer–Tropsch catalysts. The resulting catalysts display an improved performa

  19. 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 (IW

  20. Effects of loading and synthesis method of titania-supported cobalt catalysts for Fischer-Tropsch synthesis

    NARCIS (Netherlands)

    Eschemann, Thomas O.; Bitter, Johannes H.; De Jong, Krijn 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 (IW

  1. Mechanistic and kinetic analysis of the oxidative dehydrogenation of ethane via novel supported alkali chloride catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Gaertner, C.; Veen, A.C. van; Lercher, J.A. [Technische Universitaet Muenchen (Germany). Catalysis Research Center

    2013-11-01

    The oxidative dehydrogenation of ethane over advanced catalysts is promising to selectively produce ethylene, an essential building block for the chemical industry. In this way, ethane from shale gas can be efficiently valorized. Supported alkali chloride catalysts are investigated in this work. Essential feature of those materials is the presence of a solid core (magnesium oxide in part doped with Dy{sub 2}O{sub 3}) covered under reaction conditions with a molten alkali chloride shell. It is shown that especially the lowered melting point of eutectic mixtures of LiCl with other alkali/alkaline earth metals is the key to taylor highly efficient materials. Elucidating the ODH reaction mechanism is essential to understand the reactivity of this novel catalyst class and provides the basis for improving performances. Information about elementary steps and the rate determining step were extracted from kinetic measurements, both in steady state and in transient configuration. Furthermore, isotopic labelling studies were performed, i.e. SSITKA studies and temperature programmed isotopic exchange experiments. Step experiments showed a significant oxygen uptake by the catalysts. Retained oxygen reacted quantitatively with ethane at nearly 100% selectivity to ethylene and conversion rates were comparable with rates observed during steady state operation. Thus, chemically bound oxygen in the melt is the active and selective intermediate in the ODH. Therefore, it is required to consider an intermediate and the activation is concluded to relate to the oxygen dissociation. The total concentration of stored oxygen can be correlated to the steady-state activity, while the viscosity of the melts mainly influences the selectivity towards ethene. Properties of the solid core impact on the catalyst efficiency suggesting that the oxygen species forms at the interface between support and overlayer. The quantity of retained oxygen additionally depends on the properties of the chloride

  2. NiO-PTA supported on ZIF-8 as a highly effective catalyst for hydrocracking of Jatropha oil

    OpenAIRE

    Jing Liu; Jing He; Luying Wang; Rong Li; Pan Chen; Xin Rao; Lihong Deng; Long Rong; Jiandu Lei

    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-...

  3. 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.

  4. CeO_2-supported vanadium oxide catalysts for soot oxidation:the roles of molecular structure and nanometer effect

    Institute of Scientific and Technical Information of China (English)

    刘坚; 赵震; 徐春明; 段爱军; 姜桂元

    2010-01-01

    The nanometer CeO2 powder was prepared by the method of microwave-assisted heating hydrolysis,and the nanometer CeO2-supported or ordinary CeO2-supported vanadia catalysts with different vanadium loadings(atomic ratios:100V/Ce=0.1,1,4,10,and 20) were prepared by an incipient-wetness impregnation method.Spectroscopic techniques(XRD,FT-IR,Raman and UV-Vis DRS) were utilized to characterize the structures of VOx/CeO2 catalysts.The results showed that the structures of CeO2-supported vanadium oxide catalysts de...

  5. 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. PMID:26508075

  6. Investigation on C-TiO2 nanotubes composite as Pt catalyst support for methanol electrooxidation

    Science.gov (United States)

    Sui, Xu-Lei; Wang, Zhen-Bo; Yang, Min; Huo, Li; Gu, Da-Ming; Yin, Ge-Ping

    2014-06-01

    In this paper, Pt nanoparticles have been successfully deposited on the mixture of carbon black and one-dimensional self-ordered TiO2 nanotubes (TNTs) array by a microwave-assisted polyol process to synthesize Pt/C-TNTs catalyst. TiO2 nanoparticles (TNPs) are used instead of TNTs to prepare catalyst as a reference. The obtained samples are characterized by physical characterization and electrochemical measurements. The results show that Pt nanoparticles are uniformly deposited on the three-phase interfaces between carbon and TNTs. The Pt/C-TNTs possesses substantially enhanced activity and stability in electrochemical performance. Such remarkable properties are due to the excellent composite carrier of C-TNTs: (1) TNTs has strong corrosion resistance in acidic and oxidative environment and a metal support interaction between Pt and TNTs; (2) Compared to TNPs, TNTs is more suitable for electro-catalytic field on account of its better electronic conductivity; (3) Compared to TNPs, TNTs can improve the anti-poisoning ability of catalyst for methanol oxidation. (4) Amorphous carbon can improve the dispersion of platinum particles; (5) The distribution of carbon improves the poor conductivity of TNTs. These studies indicate that Pt/C-TNTs compound is a promising catalyst for methanol electrooxidation.

  7. Carbon nanotubes/tin oxide nanocomposite-supported Pt catalysts for methanol electro-oxidation.

    Science.gov (United States)

    Li, Xingwei; Wei, Jiadi; Chai, Yuzheng; Zhang, Shuo

    2015-07-15

    Carbon nanotubes/tin oxide nanocomposite (MWCNTs-SnO2) was obtained via the hydrolysis of SnCl4 in the presence of multi-walled carbon nanotubes (MWCNTs) and subsequent calcinations. And carbon nanotubes/tin oxide nanocomposite-supported Pt catalysts (Pt/MWCNTs-SnO2) were prepared by in-situ liquid phase reduction using H2PtCl6 as a metal precursor. As-prepared catalysts were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM), and their catalytic performances were evaluated by chronoamperometry (CA) and cyclic voltammetry (CV). Desirable catalytic performance for methanol electro-oxidation was observed with a reduced size and an improved dispersion of Pt catalysts on the MWCNTs-SnO2 nanocomposite. The calcination temperature of MWCNTs-SnO2 nanocomposite was a key factor for controlling the catalytic performance of Pt/MWCNTs-SnO2 catalysts. PMID:25801135

  8. Self-Supporting Metal-Organic Layers as Single-Site Solid Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Lingyun [College of Chemistry and Chemical Engineering, iCHEM, PCOSS, Xiamen University, Xiamen 361005 China; Lin, Zekai [Department of Chemistry, University of Chicago, Chicago IL 60637 USA; Peng, Fei [Berzelii Center EXCELLENT on Porous Materials, Department of Materials and Environmental Chemistry, Stockholm University, 10691 Stockholm Sweden; Wang, Weiwei [College of Chemistry and Chemical Engineering, iCHEM, PCOSS, Xiamen University, Xiamen 361005 China; Huang, Ruiyun [College of Chemistry and Chemical Engineering, iCHEM, PCOSS, Xiamen University, Xiamen 361005 China; Wang, Cheng [College of Chemistry and Chemical Engineering, iCHEM, PCOSS, Xiamen University, Xiamen 361005 China; Yan, Jiawei [College of Chemistry and Chemical Engineering, iCHEM, PCOSS, Xiamen University, Xiamen 361005 China; Liang, Jie [Berzelii Center EXCELLENT on Porous Materials, Department of Materials and Environmental Chemistry, Stockholm University, 10691 Stockholm Sweden; Zhang, Zhiming [College of Chemistry and Chemical Engineering, iCHEM, PCOSS, Xiamen University, Xiamen 361005 China; Zhang, Teng [Department of Chemistry, University of Chicago, Chicago IL 60637 USA; Long, Lasheng [College of Chemistry and Chemical Engineering, iCHEM, PCOSS, Xiamen University, Xiamen 361005 China; Sun, Junliang [Berzelii Center EXCELLENT on Porous Materials, Department of Materials and Environmental Chemistry, Stockholm University, 10691 Stockholm Sweden; College of Chemistry and Molecular Engineering, Peking University, 100871 Beijing China; Lin, Wenbin [College of Chemistry and Chemical Engineering, iCHEM, PCOSS, Xiamen University, Xiamen 361005 China; Department of Chemistry, University of Chicago, Chicago IL 60637 USA

    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.

  9. Catalytic hydrolysis of ammonia borane for hydrogen generation using cobalt nanocluster catalyst supported on polydopamine functionalized multiwalled carbon nanotube

    International Nuclear Information System (INIS)

    Hydrogen was generated from ammonia borane complex by hydrolysis using cobalt nanocluster catalyst supported on polydopamine functionalized MWCNTs (multi-walled carbon nanotubes). The impregnation-chemical reduction method was used for the preparation of the supported catalyst. The nanocluster catalyst support was formed by in-situ oxidative polymerization of dopamine on the MWCNTs in alkaline solution at room temperature. The structural and physical–chemical properties of the nanocluster catalyst were characterized by FT-IR (Fourier transform infrared spectroscopy), EDX (energy-dispersive X-ray spectroscopy), SEM (scanning electron microscope), XRD (X-ray diffraction) and TEM (transmission electron microscopy). The nanocluster catalyst showed good catalytic activity for the hydrogen generation from aqueous ammonia borane complex. A reusability test to determine the practical usage of the catalyst was also investigated. The result revealed that the catalyst maintained an appreciable catalytic performance and stability in terms of its reusability after three cycle of reuse for the hydrolysis reaction. Also, the activation energy for the hydrolysis of ammonia borane complex was estimated to be 50.41 kJmol−1, which is lower than the values of some of the reported catalyst. The catalyst can be considered as a promising candidate in developing highly efficient portable hydrogen generation systems such as PEMFC (proton exchange membrane fuel cells). - Highlights: • Co/Pdop-o-MWCNT (Pdop functionalized MWCNT supported cobalt nanocluster) catalyst was synthesized for hydrogen generation. • It is an active catalyst for hydrogen generation via hydrolysis of ammonia borane. • It showed good stability in terms of reusability for the hydrogen generation

  10. A Deep Investigation of the Thermal Decomposition Process of Supported Silver Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Jun; Xu, Tianhao; Li, Yaping; Lei, Xiaodong; Zhang, Hui; Evans, D. G.; Sun, Xiaoming; Duan, Xue [Beijing Univ. of Chemical Technology, Beijing (China)

    2014-06-15

    A deep understanding of the metallic silver catalysts formation process on oxide support and the formation mechanism is of great scientific and practical meaning for exploring better catalyst preparing procedures. Herein the thermal decomposition process of supported silver catalyst with silver oxalate as the silver precursor in the presence of ethylenediamine and ethanolamine is carefully investigated by employing a variety of characterization techniques including thermal analysis, in situ diffuse reflectance infrared Fourier transform spectroscopy, scanning electron microscopy, and X-ray diffraction. The formation mechanism of supported silver particles was revealed. Results showed that formation of metallic silver begins at about 100 .deg. C and activation process is essentially complete below 145 .deg. C. Formation of silver was accompanied by decomposition of oxalate group and removal of organic amines. Catalytic performance tests using the epoxidation of ethylene as a probe reaction showed that rapid activation (for 5 minutes) at a relatively low temperature (170 .deg. C) afforded materials with optimum catalytic performance, since higher activation temperatures and/or longer activation times resulted in sintering of the silver particles.

  11. 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.)

  12. Cluster-support interactions and morphology of MoS2 nanoclusters in a graphite-supported hydrotreating model catalyst.

    Science.gov (United States)

    Kibsgaard, Jakob; Lauritsen, Jeppe V; Laegsgaard, Erik; Clausen, Bjerne S; Topsøe, Henrik; Besenbacher, Flemming

    2006-10-25

    Supported MoS(2) nanoparticles constitute the active component of the important hydrotreating catalysts used for industrial upgrading and purification of the oil feedstock for the production of fossil fuels with a low environmental load. We have synthesized and studied a model system of the hydrotreating catalyst consisting of MoS(2) nanoclusters supported on a graphite surface in order to resolve a number of very fundamental questions related to the atomic-scale structure and morphology of the active clusters and in particular the effect of a substrate used in some types of hydrotreating catalysts. Scanning tunneling microscopy (STM) is used to image the atomic-scale structure of graphite-supported MoS(2) nanoclusters in real space. It is found that the pristine graphite (0001) surface does not support a high dispersion of MoS(2), but by introducing a small density of defects in the surface, highly dispersed MoS(2) nanoclusters could be synthesized on the graphite. From high-resolution STM images it is found that MoS(2) nanoclusters synthesized at low temperature in a sulfiding atmosphere preferentially grow as single-layer clusters, whereas clusters synthesized at 1200 K grow as multilayer slabs oriented with the MoS(2)(0001) basal plane parallel to the graphite surface. The morphology of both single-layer and multilayer MoS(2) nanoclusters is found to be preferentially hexagonal, and atom-resolved images of the top facet of the clusters provide new atomic-scale information on the MoS(2)-HOPG bonding. The structure of the two types of catalytically interesting edges terminating the hexagonal MoS(2) nanoclusters is also resolved in atomic detail in STM images, and from these images it is possible to reveal the atomic structure of both edges and the location and coverage of sulfur and hydrogen adsorbates.

  13. Cobalt salophen complex supported on imidazole functionalized magnetic nanoparticles as a recoverable catalyst for oxidation of alkenes

    Energy Technology Data Exchange (ETDEWEB)

    Afshari, Mozhgan, E-mail: m.afshari@iau-shoushtar.ac.ir [Department of Chemistry, Shoushtar Branch, Islamic Azad University, Shoushtar (Iran, Islamic Republic of); Gorjizadeh, Maryam [Department of Chemistry, Shoushtar Branch, Islamic Azad University, Shoushtar (Iran, Islamic Republic of); Nazari, Simin [Department of Chemistry, Sousangerd Branch, Islamic Azad University, Sousangerd (Iran, Islamic Republic of); Naseh, Mohammad [Department of Chemistry, Dezful Branch, Islamic Azad University, Dezful (Iran, Islamic Republic of)

    2014-08-01

    A new magnetically separable catalyst consisting of Co(II) salophen complex covalently supported on imidazole functionalized silica coated cobalt ferrite was prepared. The synthesized catalyst was characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), vibrating sample magnetometry (VSM), thermogravimetric analysis (TGA), inductively coupled plasma atomic emission spectroscopy (ICP-AES) and Fourier transform infrared (FT-IR). The immobilized catalyst was shown to be an efficient heterogeneous catalyst for the oxidation of some alkenes using hydrogen peroxide (H{sub 2}O{sub 2}) as oxidant. The catalyst could be easily and efficiently isolated from the final product solution by magnetic decantation and be reused for 5 consecutive reactions without showing any significant activity degradation. - Highlights: • A new magnetic catalyst consisting of Co(II) salophen complex was prepared. • The catalyst was shown to be an efficient catalyst for the oxidation of alkenes. • The catalyst could be easily isolated from the product by magnetic decantation. • The catalyst is reused 5 times without a significant loss of activity.

  14. Carbon Aerogel-Supported Pt Catalysts for the Hydrogenolysis and Isomerization of n-Butane: Influence of the Carbonization Temperature of the Support and Pt Particle Size

    Directory of Open Access Journals (Sweden)

    Marta B. Dawidziuk

    2012-10-01

    Full Text Available Carbon aerogels prepared at different carbonization temperatures and with varying mesopore volumes were used as supports for Pt catalysts to study the n-C4H10/H2 reaction. Mean Pt particle size depended on the mesopore volume of the support, showing a linear decrease when the mesopore volume increased. The turnover frequency (TOF for hydrogenolysis was much higher than for isomerization in catalysts supported on carbon aerogels obtained at 900–950 °C. However, both TOF values were similar in catalysts supported on the carbon aerogel obtained at 500 °C. TOF for hydrogenolysis and isomerization were related to the mean Pt particle size in catalysts supported on carbon aerogels obtained at 900–950 °C. In addition, both reactions showed a compensation effect between the activation energy and pre-exponential factor, indicating that they have the same intermediate, i.e., the chemisorbed dehydrogenated alkane.

  15. Carbon Nanotubes Supported Pt-Ru-Ni as Methanol Electro-Oxidation Catalyst for Direct Methanol Fuel Cells

    Institute of Scientific and Technical Information of China (English)

    Fei Ye; Shengzhou Chen; Xinfa Dong; Weiming Lin

    2007-01-01

    Carbon nanotubes (CNTs) supported Pt-Ru and Pt-Ru-Ni catalysts were prepared by chemical reduction of metal precursors with sodium borohydride at room temperature. The crystallographic properties and composition of the catalysts were characterized by X-ray diffraction (XRD) and energy dispersive X-ray (EDX) analysis, and the catalytic activity and stability for methanol electro-oxidation were measured by electrochemical impedance spectroscopy (EIS), linear sweep voltammetries (LSV), and chronoamperometry (CA). The results show that the catalysts exhibit face-centered cubic (fcc) structure.The particle size of Pt-Ru-Ni/CNTs catalyst is about 4.8 nm. The catalytic activity and stability of the Pt-Ru-Ni/CNTs catalyst are higher than those of Pt-Ru/CNTs catalyst.

  16. Microwave assisted synthesis of biarlys by Csbnd C coupling reactions with a new chitosan supported Pd(II) catalyst

    Science.gov (United States)

    Baran, Talat; Menteş, Ayfer

    2016-10-01

    In this study a new type chitosan-based support has been produced for Pd(II) catalyst and its catalytic performance in Suzuki Csbnd C reactions has been studied under microwave irradiation without using any solvent. The chemical identification of the catalyst was performed using TG/DTG, FTIR, UV-Vis ICP-OES, SEM/EDAX, 13C NMR, molar conductivity, XRD and magnetic moment techniques. The performance of this new Pd(II) catalyst was studied in Suzuki Csbnd C reactions. The Pd(II) catalyst exhibited a good catalytic performance in very short time (4 min) by giving high TONs and TOFs with low amount of the catalyst (0.015 mol%). The catalyst also had reusability and did not lose its activity until six runs.

  17. 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......Significant differences in catalyst performance and durability are often observed between the use of a liquid electrolyte (e.g. sulfuric acid), and a solid polymer electrolyte (e.g. Nafion®). To understand this phenomenon, we studied the electrochemical behavior of a commercially available carbon...... that the catalyst performance and stability are very much influenced by the presence of the Nafion ionomers. The proton conducting phase provided by the ionomer and the self-assembled electrode structure render the catalysts a higher utilization and better stability. This is probably due to an enhanced dispersion...

  18. Facial synthesis of porous hematite supported Pt catalyst and its photo enhanced electrocatalytic ethanol oxidation performance

    International Nuclear Information System (INIS)

    Graphical Abstract: A porous α-Fe2O3 supported Pt catalyst has been synthesized by a facial thermal treatment assisted precipitation method and the materials show a illumination enhanced performance for ethanol oxidation. Display Omitted -- Highlights: •A porous α-Fe2O3 supported Pt catalyst has been synthesized for the first time. •With the addition of α-Fe2O3, the current density of Pt/C grows about 51% under illumination and 32% in the dark compared with unsupported catalyst. •The current increases under illuminationin chronoamperometric experiments at a given potential of 0.7 V due to the photons from light provide energy for CO stripping. •This work demostrates an optical strategy to accelerate electrode reactions towards ethanol oxidation reaction. -- Abstract: The porous α-Fe2O3 supported Pt catalyst is synthesized by a facial thermal treatment assisted precipitation method. The particle size of Pt is less than 3 nm. The pore diameters of α-Fe2O3 particles are concentrated to 2.46 nm in a mesooporous scale. Its electrochemical performance is tested. The ethanol oxidation current of the Pt/Fe2O3 catalsyt obviously improves under illumination, compared with that in the dark, during the optical switching operation. Moreover, with the addition of α-Fe2O3, the ethanol oxidation current of Pt/C grows about 51% under illumination and 32% in the dark; the onset potential shifts negtively for about 20 mV. This work demostrates an optical strategy which can be a potential alternative to accelerate electrode reactions towards ethanol oxidation reaction

  19. Synthesis, characterization, and catalytic activity in Suzuki coupling and catalase-like reactions of new chitosan supported Pd catalyst.

    Science.gov (United States)

    Baran, Talat; Inanan, Tülden; Menteş, Ayfer

    2016-07-10

    The aim of this study is to analyze the synthesis of a new chitosan supported Pd catalyst and examination of its catalytic activity in: Pd catalyst was synthesized using chitosan as a biomaterial and characterized with FTIR, TG/DTG, XRD, (1)H NMR, (13)C NMR, SEM-EDAX, ICP-OES, Uv-vis spectroscopies, and magnetic moment, along with molar conductivity analysis. Biomaterial supported Pd catalyst indicated high activity and long life time as well as excellent turnover number (TON) and turnover frequency (TOF) values in Suzuki reaction. Biomaterial supported Pd catalyst catalyzed H2O2 decomposition reaction with considerable high activity using comparatively small loading catalyst (10mg). Redox potential of biomaterial supported Pd catalyst was still high without negligible loss (13% decrease) after 10 cycles in reusability tests. As a consequence, eco-friendly biomaterial supported Pd catalyst has superior properties such as high thermal stability, long life time, easy removal from reaction mixture and durability to air, moisture and high temperature.

  20. 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

  1. Heterogeneous activation of peroxymonosulphate by supported ruthenium catalysts for phenol degradation in water

    International Nuclear Information System (INIS)

    Highlights: ► RuO2/ZSM5 and RuO2/AC exhibited higher activity in Oxone activation with stable performance. ► RuO2/AC presented higher activity than RuO2/ZSM5. ► Phenol degradation on RuO2/AC and RuO2/ZSM5 followed first order kinetics. - Abstract: Activated carbon (AC) and Zeolite Socony Mobil-5 (ZSM5) supported ruthenium oxide catalysts were prepared and tested to degrade aqueous phenol in the presence of peroxymonosulphate. The physicochemical properties of ruthenium oxide based catalysts were characterised by several techniques such as XRD (X-ray diffraction), SEM-EDS (scanning electron microscopy-energy dispersive X-ray spectroscopy), and N2 adsorption. It was found that RuO2/AC was highly effective in heterogeneous activation of peroxymonosulphate to produce sulphate radicals, presenting higher reaction rate in phenol degradation compared with RuO2/ZSM-5. Degradation efficiency of phenol could be achieved at 100% of phenol decomposition and 60% of total organic carbon (TOC) removal in 1 h at the conditions of 50 ppm phenol, 0.2 g catalyst, 1 g Oxone® in 500 mL solution at 25 °C using the two catalysts. It was also found that phenol degradation was strongly influenced by catalyst loading, phenol concentration, Oxone® concentration and temperature. Kinetic studies proved that a pseudo first order kinetics would fit to phenol decomposition and the activation energies for RuO2/AC and RuO2/ZSM5 were obtained to be 61.4 and 42.2 kJ/mol, respectively.

  2. Highly Active Carbon Supported Pd-Ag Nanofacets Catalysts for Hydrogen Production from HCOOH.

    Science.gov (United States)

    Wang, Wenhui; He, Ting; Liu, Xuehua; He, Weina; Cong, Hengjiang; Shen, Yangbin; Yan, Liuming; Zhang, Xuetong; Zhang, Jinping; Zhou, Xiaochun

    2016-08-17

    Hydrogen is regarded as a future sustainable and clean energy carrier. Formic acid is a safe and sustainable hydrogen storage medium with many advantages, including high hydrogen content, nontoxicity, and low cost. In this work, a series of highly active catalysts for hydrogen production from formic acid are successfully synthesized by controllably depositing Pd onto Ag nanoplates with different Ag nanofacets, such as Ag{111}, Ag{100}, and the nanofacet on hexagonal close packing Ag crystal (Ag{hcp}). Then, the Pd-Ag nanoplate catalysts are supported on Vulcan XC-72 carbon black to prevent the aggregation of the catalysts. The research reveals that the high activity is attributed to the formation of Pd-Ag alloy nanofacets, such as Pd-Ag{111}, Pd-Ag{100}, and Pd-Ag{hcp}. The activity order of these Pd-decorated Ag nanofacets is Pd-Ag{hcp} > Pd-Ag{111} > Pd-Ag{100}. Particularly, the activity of Pd-Ag{hcp} is up to an extremely high value, i.e., TOF{hcp} = 19 000 ± 1630 h(-1) at 90 °C (lower limit value), which is more than 800 times higher than our previous quasi-spherical Pd-Ag alloy nanocatalyst. The initial activity of Pd-Ag{hcp} even reaches (3.13 ± 0.19) × 10(6) h(-1) at 90 °C. This research not only presents highly active catalysts for hydrogen generation but also shows that the facet on the hcp Ag crystal can act as a potentially highly active catalyst. PMID:27454194

  3. Pristine and supported ZnO-based catalysts for phenazopyridine degradation with direct solar light

    Science.gov (United States)

    Hilal, Hikmat S.; Al-Nour, Ghazi Y. M.; Zyoud, Ahed; Helal, Muath H.; Saadeddin, Iyad

    2010-04-01

    In search for safe techniques to manage waste pharmaceutical compounds drained in water, solar-driven degradation of phenazopyridine (a model drug) was investigated in aqueous media using different ZnO-based catalyst systems. Naked ZnO, CdS-sensitized ZnO (ZnO/CdS) and activated carbon-supported ZnO (AC/ZnO) have been studied. Both naked ZnO and AC/ZnO were highly efficient in mineralizing phenazopyridine, reaching complete removal in ˜50 min, with AC/ZnO having the higher edge. The ZnO/CdS system showed lower efficiency, due to screening of light by CdS. Moreover, the tendency of CdS to leach out Cd 2+ ions discouraged the use of CdS as sensitizer in this work. In both ZnO and AC/ZnO systems, the photo-degradation reaction was induced by the UV tail of the solar light. The visible region, with wavelength longer than 400 nm, failed to induce photo-degradation. The reaction was faster with higher catalyst loading, until a maximum efficiency was reached at a certain concentration. The rate of reaction increased with higher drug concentrations up to a certain limit. The effect of pH value was studied, and the catalysts showed highest efficiencies at pH close to 7. Stability of ZnO to degradation was studied. Both catalyst systems showed lowered efficiencies on recovery and reuse. The results suggest that complete mineralization of waste drugs, commonly dumped in sewage water, with direct solar light is a potentially feasible strategy using the AC/ZnO catalyst.

  4. Studies of supported metal catalysts. Progress report, September 1, 1979-August 31, 1980

    International Nuclear Information System (INIS)

    Research was carried out on four separate catalyst systems: Co-Al2O3; Mo-Al2O3; Co/Mo/Al2O3; and Ni. Work was completed on the interactions between cobalt and γ-Al2O3. Work was begun on the combined Co/Mo/Al2O3 system. A separate study is in progress on support interactions between nickel and a variety of supports; particular emphasis has been on the effect of preparation method

  5. Oxide-supported PtCo alloy catalyst for intermediate temperature polymer electrolyte fuel cells

    OpenAIRE

    Stassi, Alessandro; Gatto, Irene; Baglio, Vincenzo; Passalacqua, Enza; Aricò, Antonino S.

    2013-01-01

    International audience A Pt-Co alloy catalyst supported on a Ta-doped Ti-oxide was investigated for the oxygen reduction reaction in a polymer electrolyte fuel cell (PEMFC) operating between 80° and 110 °C at different relative humidity (100% and 33% R.H.). A crystalline Anatase phase was obtained for the Ta-doped Ti-oxide support with BET surface area of about 150 m2/g. Pt and Pt3Co1 nanoparticles dispersed on the Ta-doped Ti-oxide showed a crystallite size of 3.9 and 2.9 nm, respectively...

  6. Low-temperature SCR of NO{sub x} with NH{sub 3} over carbon-ceramic supported catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Valdes-Solis, Teresa; Marban, Gregorio; Fuertes, Antonio B. [Instituto Nacional del Carbon (CSIC), c/Francisco Pintado Fe No. 26, 33011 Oviedo (Spain)

    2003-11-10

    A new method for preparing vanadium oxide supported on carbon-ceramic cellular monoliths is described. This includes a support oxidation step with HNO{sub 3}, followed by ionic exchange with a NaOH solution, equilibrium adsorption impregnation of VO{sup 2+} and thermal treatment. As a result an active catalyst for low-temperature selective catalytic reduction (SCR) reaction is obtained. The V-catalyst is more resistant to SO{sub 2} poisoning than the previously developed Mn-catalyst. Inhibition by water is reversible for both types of catalysts. Testing of the vanadium catalyst after subjecting it to the outlet gas stream of a power plant shows fast deactivation until constant residual activity is reached. Deactivation seems to be caused by arsenic poisoning and the formation of superficial sulphates.

  7. N-doped mesoporous carbons supported palladium catalysts prepared from chitosan/silica/palladium gel beads.

    Science.gov (United States)

    Zeng, Minfeng; Wang, Yudong; Liu, Qi; Yuan, Xia; Feng, Ruokun; Yang, Zhen; Qi, Chenze

    2016-08-01

    In this study, a heterogeneous catalyst including palladium nanoparticles supported on nitrogen-doped mesoporous carbon (Pd@N-C) is synthesized from palladium salts as palladium precursor, colloidal silica as template, and chitosan as carbon source. N2 sorption isotherm results show that the prepared Pd@N-C had a high BET surface area (640m(2)g(-1)) with large porosity. The prepared Pd@N-C is high nitrogen-rich as characterized with element analysis. X-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy (HR-TEM), and Raman spectroscopy characterization of the catalyst shows that the palladium species with different chemical states are well dispersed on the nitrogen-containing mesoporous carbon. The Pd@N-C is high active and shows excellent stability as applied in Heck coupling reactions. This work supplies a successful method to prepare Pd heterogeneous catalysts with high performance from bulk biopolymer/Pd to high porous nitrogen-doped carbon supported palladium catalytic materials. PMID:27155234

  8. Towards rational design of catalysts supported on a topological insulator substrate

    CERN Document Server

    Xiao, Jianping; Yam, Chi-Yung; Frauenheim, Thomas; Yan, Binghai

    2015-01-01

    Exotic and robust metallic surface states of topological insulators (TIs) have been expected to provide a promising platform for novel surface chemistry and catalysis. However, it is still an unprecedented field how TIs affect the activity of catalysts. In this work, we study the effects of topological surface states (TSSs) on the activity of transition metal clusters (Au, Ag, Cu, Pt, and Pd), which are supported on a TI Bi2Se3 substrate. It was found the adsorption energy of oxygen on the supported catalysts can be always enhanced due to the TSSs. However, it does not necessarily mean an increase of the activity in catalytic oxidation reaction. Rather, the enhanced adsorption behavior in the presence of TSSs exhibits dual effects, determined by the intrinsic reactivity of these catalysts with oxygen. For the Au case, the activity of catalytic oxidation can be improved because the intrinsic binding between Au and O is relatively weak. In contrast, a negative effect is found for the Pt and Pd clusters since th...

  9. RuCu nanoparticles supported on graphene: A highly efficient catalyst for hydrolysis of ammonia borane

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Nan; Hu, Kai [College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, Hubei 430072 (China); Luo, Wei, E-mail: wluo@whu.edu.cn [College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, Hubei 430072 (China); Suzhou Institute of Wuhan University, Suzhou, Jiangsu, 215123 (China); Cheng, Gongzhen, E-mail: gzcheng@whu.edu.cn [College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, Hubei 430072 (China)

    2014-03-25

    Graphical abstract: Well dispersed RuCu/graphene nanoparticles exerted satisfied catalytic activity and recycle stability towards the hydrolysis of ammonia borane. Highlights: • One-step in situ synthesis of graphene supported RuCu NPs. • The catalysts exhibit excellent catalytic activity toward hydrolysis of AB. • Graphene supported NPs exhibit the highest catalytic activity. -- Abstract: Well dispersed RuCu nanoparticles (NPs) supported on graphene were in situ synthesized by a one-step co-reduction of aqueous solution of ruthenium (III) chloride, cupric (II) chloride, and graphite oxide (GO) with ammonia borane (AB) under ambient condition. The nature of the NPs was fully characterized by TEM, HRTEM, XRD, energy dispersive spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS). The as-synthesized NPs exhibit much higher catalytic activity for hydrolytic dehydrogenation of AB than the monometallic Ru and Cu, bimetallic RuCu/graphene reduced by NaBH{sub 4}, and graphene free RuCu counterparts. Additionally, the as-synthesized NPs supported on graphene exhibit higher catalytic activity than the catalysts with other conventional supports, such as SiO{sub 2}, γ-Al{sub 2}O{sub 3}, and carbon black. The activity of Ru{sub 1}Cu{sub 7.5}/graphene NPs in terms of turnover frequency (TOF) is 135 mol H{sub 2} min{sup −1} (mol Ru){sup −1}, which is higher than Ru/graphene, and most reported Ru-based or other noble metal-based NPs for the catalytic hydrolysis of AB. The activation energy for hydrolysis of AB in the presence of Ru{sub 1}Cu{sub 7.5}/graphene NPs was determined as 30.59 kJ mol{sup −1}, which is lower than most of the reported catalysts. Furthermore, the as-prepared NPs exert satisfied durable stability for the hydrolytic dehydrogenation of AB.

  10. 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.

  11. High-performance PdRu bimetallic catalyst supported on mesoporous silica nanoparticles for phenol hydrogenation

    Science.gov (United States)

    Huang, Chao; Yang, Xu; Yang, Hui; Huang, Peiyan; Song, Huiyu; Liao, Shijun

    2014-10-01

    A high-performance PdRu bimetallic catalyst supported on mesoporous silica nanoparticles (MSN), PdRu/MSN, was prepared by a facile impregnation-hydrogen reduction method. It was found that PdRu/MSN showed 5 times higher activity than that of Pd/MSN towards the liquid-phase hydrogenation of phenol. The catalysts were characterized comprehensively by multiple techniques, X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and hydrogen temperature program reduction (TPR). It was revealed that adding Ru could effectively improve the Pd dispersion and promote the electronic interaction between the Pd and Ru, both of which contribute to enhancing the catalytic activity.

  12. Microwave-assisted synthesis of carbon-supported carbides catalysts for hydrous hydrazine decomposition

    Science.gov (United States)

    Mnatsakanyan, Raman; Zhurnachyan, Alina R.; Matyshak, Valery A.; Manukyan, Khachatur V.; Mukasyan, Alexander S.

    2016-09-01

    Microwave-assisted synthesis of carbon-supported Mo2C and WC nanomaterials was studied. Two different routes were utilized to prepare MoO3 (WO3) - C precursors that were then subjected to microwave irradiation in an inert atmosphere. The effect of synthesis conditions, such as irradiation time and gas environment, was investigated. The structure and formation mechanism of the carbide phases were explored. As-synthesized nanomaterials exhibited catalytic activity for hydrous hydrazine (N2H4·H2O) decomposition at 30-70 °C. It was shown that the catalyst activity significantly increases if microwave irradiation is applied during the decomposition process. Such conditions permit complete conversion of hydrazine to ammonia and nitrogen within minutes. This effect can be attributed to the unique nanostructure of the catalysts that includes microwave absorbing carbon and active carbide constituents.

  13. Degradation of trichloroethylene by hydrodechlorination using formic acid as hydrogen source over supported Pd catalysts.

    Science.gov (United States)

    Yu, Xin; Wu, Ting; Yang, Xue-Jing; Xu, Jing; Auzam, Jordan; Semiat, Raphael; Han, Yi-Fan

    2016-03-15

    An advanced method for the degradation of trichloroethylene (TCE) over Pd/MCM-41 catalysts through a hydrogen-transfer was investigated. Formic acid (FA) was used instead of gaseous H2 as the hydrogen resource. As a model H-carrier compound, FA has proven to yield less by-products and second-hand pollution during the reaction. Several factors have been studied, including: the property of catalyst supports, Pd loading and size, temperature, initial concentrations of FA and TCE (potential impact on the reaction rates of TCE degradation), and FA decomposition. The intrinsic kinetics for TCE degradation were measured, while the apparent activation energies and the reaction orders with respect to TCE and FA were calculated through power law models. On the basis of kinetics, we assumed a plausible reaction pathway for TCE degradation in which the catalytic degradation of TCE is most likely the rate-determining step for this reaction. PMID:26685065

  14. Size control of rhodium particles of silica-supported catalysts using water-in-oil microemulsion

    Science.gov (United States)

    Kishida, Masahiro; Hanaoka, Toshiaki; Kim, Won Young; Nagata, Hideo; Wakabayashi, Katsuhiko

    1997-11-01

    Effects of components of water-in-oil microemulsions on rhodium particle sizes of silica-supported rhodium catalysts were investigated in the catalyst preparation method using microemulsion. In the case of the microemulsion of polyoxyethylene(23)dodecyl ether/ n-alcohols/RhCl 3 aq., the rhodium particle size increased from 3.4 to 5.0 nm as the specific permittivity of the organic solvent increased. The chain length of hydrophilic group of polyoxyethylene- p-nonylphenyl ether ( n = 5 to 15) employed as surfactants had an effect on the rhodium particle size where the rhodium size ranged between 2.0 and 3.6 nm. The rhodium particle size was 1.5 nm in the case of sodium bis(2-ethylhexyl) sulfocuccinate and this value was found to be the smallest. These results could be interpreted in terms of the adsorption of the surfactant on rhodium-hydrazine particle surface.

  15. Durability of ZSM5 supported Co-Pd catalysts in the reduction of NOx with methane

    International Nuclear Information System (INIS)

    Selective catalytic reduction of NO with CH4 was studied over ZSM5-based cobalt (Co) and palladium (Pd) catalysts in the presence of oxygen and water. Pore volume impregnation of cobalt was found to be more efficient and much simpler than the common (wet) ion-exchange method. In the case of Pd, wet ion-exchange was found to give superior activity. As compared to alternative catalytic systems reported in literature for CH-4-SCR in the presence of water, ZSM5 supported Co-Pd combination catalysts are very active and selective. The activity of the ZSM5-based Co-Pd combination catalysts, however, decreases strongly with time on stream. Strikingly, this deactivation is not (predominantly) caused by steam dealumination of the zeolites: loss of SCR activity with time on stream occurs irrespective of the presence or absence of water in the feed. The higher the temperature of calcination the lower the initial activity and the faster the deactivation. In addition to this, the deactivation is also more pronounced at higher reaction temperatures. These observations are consistent with a temperature-induced mechanism of ion migration and sintering as also confirmed by TPR analysis. The role of water in this migration process is not obvious. Hence, the limited thermal stability of ZSM5 supported metal (ion) catalysts leads to two demands, which have yet to be made for application of zeolites in CH4-SCR: (1) stabilisation of the ionic phases in zeolite pores of different geometry and (2) further improved activity and selectivity allowing one to operate at temperatures that do not exceed 350-400C, where deactivation is not significant

  16. Durability of ZSM5-supported Co-Pd catalysts in the reduction of NOx with methane

    International Nuclear Information System (INIS)

    Selective catalytic reduction (SCR) of NO with CH4 was studied over ZSM5-based cobalt and palladium catalysts in the presence of oxygen and water. Pore volume impregnation of cobalt was found to be more efficient and much simpler than the common (wet) ion-exchange method. In the case of Pd, wet ion-exchange was found to give superior activity. As compared to alternative catalytic systems reported in literature for CH4-SCR in the presence of water, ZSM5-supported Co-Pd combination catalysts are very active and selective. The activity of the ZSM5-based Co-Pd combination catalysts, however, decreases strongly with time-on-stream. Strikingly, this deactivation is not (predominantly) caused by steam dealumination of the zeolites: loss of SCR activity with time-on-stream occurs irrespective of the presence or absence of water in the feed. The higher the temperature of calcination the lower the initial activity and the faster the deactivation. In addition to this, the deactivation is also more pronounced at higher reaction temperatures. These observations are consistent with a temperature-induced mechanism of ion migration and sintering as also confirmed by TPR analysis. The role of water in this migration process is not obvious. Hence, the limited thermal stability of ZSM5-supported metal (ion) catalysts leads to two demands, which have yet to be made for application of zeolites in CH4-SCR: (1) stabilisation of the ionic phases in zeolite pores of different geometry; and (2) further improved activity and selectivity allowing one to operate at temperatures that do not exceed 350-400C, where deactivation is not significant

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

    OpenAIRE

    Jakkrit Suriboot; Hassan S. Bazzi; Bergbreiter, David E.

    2016-01-01

    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 th...

  18. Low-temperature steam-reforming of ethanol over ZnO-supported Ni and Cu catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Homs, Narcis; Llorca, Jordi; De la Piscina, Pilar Ramirez [Departament de Quimica Inorganica, Universitat de Barcelona, C/Marti i Franques 1-11, 08028 Barcelona (Spain)

    2006-08-15

    ZnO-supported Ni and Cu as well as bimetallic Co-Ni and Co-Cu catalysts containing ca. 0.7wt% sodium promoter and prepared by the co-precipitation method were tested in the ethanol steam-reforming reaction at low temperature (523-723K), using a bioethanol-like mixture diluted in Ar. Monometallic ZnO-supported Cu or Ni samples do not exhibit good catalytic performance in the steam-reforming of ethanol for hydrogen production. Copper catalyst mainly dehydrogenates ethanol to acetaldehyde, whereas nickel catalyst favours ethanol decomposition. However, the addition of Ni to ZnO-supported cobalt has a positive effect both on the production of hydrogen at low temperature (<573K), and on catalyst stability. Evidence for alloy formation as well as mixed oxides at the microstructural level was found in the bimetallic systems after running the ethanol steam-reforming reaction by HRTEM-EELS. (author)

  19. 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

  20. Based on a new support for synthesis of highly efficient palladium/hydroxyapatite catalyst for ethanol electrooxidation

    International Nuclear Information System (INIS)

    Based on a new support, hydroxyapatite (HAP), a facile and low–cost preparation of palladium/hydroxyapatite catalyst for ethanol electrooxidation is introduced in this paper through a solvothermal reaction without additives. HAP was employed as the catalyst support for its hydroxyl–rich surface in order to increase the stability and utilization ratio of catalyst. According to transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM) and X–ray diffraction (XRD) measurements, the as–prepared Pd nanoparticles with face–centered cubic crystal structure were evenly deposited on the surface of HAP. Cyclic voltammetry and chronoamperometry tests demonstrated that the Pd/HAP catalyst possessed a much higher current density (246 mA cm−2) than the Pd/C catalyst (109 mA cm−2) towards ethanol electrooxidation, and better stability as well. In the direct ethanol fuel cell (DEFC) test, Pd/HAP catalyst gives better performance than that with Pd/C in terms of both open-circuit voltage (OCV) and power density. These results indicate that the HAP is a better support and the catalyst developed in this study may be a better candidate for DEFCs. A possible mechanism consistent with the experimental is also proposed

  1. Deactivation of carbon supported palladium catalyst in direct formic acid fuel cell

    International Nuclear Information System (INIS)

    A new carbon black supported palladium catalyst for direct formic acid fuel cell applications has been prepared and characterized by X-ray diffraction. Bi-modal distribution of Pd crystallite sizes was observed. The average Pd size for crystallites in small size and large size ranges were about 2.7 nm and 11.2 nm, respectively. The initial activity of the catalyst in the oxidation of formic acid tested in a fuel cell was similar to a commercial well dispersed 20 wt.% Pd/Vulcan. The rates of the fuel cell power decay were measured for formic acid of two purities for various current loadings. The results showed that various mechanisms contribute to the decrease of cell power with time. In direct formic acid fuel cell (DFAFC) fed with a very pure HCOOH accumulation of CO2 gas bubbles in anode catalyst layer is responsible for observed power decay. In DFAFC fed with a pure for analysis (p.a.) grade formic acid the formation of COads poison from the formic acid impurities is the main deactivation reason.

  2. Mesoporous synthetic clays : synthesis, characterization, and use as HDS catalyst supports.

    Energy Technology Data Exchange (ETDEWEB)

    Bloomquist, C. A. A.; Carrado, K. A.; Marshall, C. L.; Seifert, S.; Wei, D.; Xu, L.

    1999-08-10

    Mesoporous synthetic clays (MSCs) are obtained when polymer-containing silicate gels are hydrothermally crystallized to form layered magnesium silicate hectorite clays containing polymers that are incorporated in situ. Polyvinylpyrrolidone of several average molecular weights ranging from 10K to 1.3M, in gel loadings varying from 5-30 wt%, were used. The organic polymer template molecules were removed from synthetic polymer-clay complexes via calcination. Pore radii, surface areas, and pore volumes of the resulting porous inorganic networks were then measured. For the most part there is a direct correlation between both PVP molecular weight and polymer loading on the diameter of the average pore. In addition to conventional techniques, the polymer-clay materials were also characterized by small angle x-ray scattering to ascertain the disposition of the polymeric matrix. The MSC materials after calcination were examined as potential supports for hydrodesulfurization (HDS). They were loaded with a bimetallic Co/Mo catalyst system for comparison with a commercial Co/Mo alumina catalyst. Dibenzothiophene (DBT) diluted with hexadecane (0.75 wt% S) was utilized as a liquid feed for the HDS tests. This feed was chosen as a deep HDS test of a heavy model oil. The pore diameters of the MSC catalysts were found to have a strong effect on both the HDS activity and selectivity.

  3. Hydrogen production from lignin with supported nickel catalysts through supercritical water gasification

    International Nuclear Information System (INIS)

    The production of hydrogen through the gasification of lignin was examined with nickel supported magnesium oxide catalysts in supercritical water at 673 K. In the absence of nickel (MgO only), the amount of gases were very low and almost all of lignin were decomposed to THF insoluble. The increase in the amount of nickel on catalyst leaded to the increase in the amount of gases. In this reaction, the magnesium oxide decomposed the lignin to lower molecular components. The nickel probably promoted the participation of hydrogen and oxygen atom to form gases through the gasification of lignin. The gas yield was attained almost 80% in a carbon basis at 673 K and 0.3 g/cm3 of water density. The main gas components were methane, carbon dioxide, hydrogen and these composition were about 54%, 40% and 6%, respectively. These results indicate that the biomass can be converted to gases including hydrogen by using nickel catalyst at low temperature region. (authors)

  4. Preparation and characterization of silica-supported Ni/Pt catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Raab, C.; Lercher, J.A. (Universitaet Wien, Vienna (Austria)); Goodwin, J.G. Jr. (Univ. of Pittsburgh, PA (USA)); Shyu, J.Z. (Amoco Research Center, Naperville, IL (USA))

    1990-04-01

    The formation of a series of Ni/Pt catalysts was investigated by means of temperature programmed reduction (TPR) of the chloride precursor, hydrogen chemisorption, x-ray diffraction, scanning electron microscopy, XPS, and magnetic measurements. An alloy between Pt and Ni was formed. The minority constituent of the series of bimetallic catalysts was always found to be quantitatively alloyed or in close contact with the more abundant metal. For several samples, the stoichiometric NiPt compound was observed. With Ni-rich samples a nonstoichiometric alloy (rich in Ni) was concluded to exist. At all concentration levels the presence of Pt facilitated the reduction of Ni{sup 2+} significantly. Temperature-programmed reduction of the Ni/Pt catalyst with 50 mol% and higher concentrations of Pt did not differ from that of pure Pt. Based on XPS and magnetic measurements it is concluded that a constant fraction (approximately 10-15%) of Ni was highly dispersed and interacted strongly with the support. 30 refs.

  5. Production of Carbon Nanofibers Using a CVD Method with Lithium Fluoride as a Supported Cobalt Catalyst

    Directory of Open Access Journals (Sweden)

    S. A. Manafi

    2008-01-01

    Full Text Available Carbon nanofibers (CNFs have been synthesized in high yield (>70% by catalytic chemical vapor deposition (CCVD on Co/LiF catalyst using acetylene as carbon source. A novel catalyst support (LiF is reported for the first time as an alternative for large-scale production of carbon nanofibers while purification process of nanofibers is easier. In our experiment, the sealed furnace was heated at 700∘C for 0.5 hour (the heating rate was 10∘C/min and then cooled to room temperature in the furnace naturally. Catalytic chemical vapor deposition is of interest for fundamental understanding and improvement of commercial synthesis of carbon nanofibers (CNFs. The obtained sample was sequentially washed with ethanol, dilutes acid, and distilled water to remove residual impurities, amorphous carbon materials, and remaining of catalyst, and then dried at 110∘C for 24 hours. The combined physical characterization through several techniques, such as high-resolution transmission electron microscope (TEM, scanning electron microscope (SEM, thermogarvimetric analysis (TGA, and zeta-sizer and Raman spectroscopy, allows determining the geometric characteristic and the microstructure of individual carbon nanofibers. Catalytic chemical vapor deposition is of interest for fundamental understanding and improvement of commercial synthesis of carbon nanofibers (CNFs. As a matter of fact, the method of CCVD guarantees the production of CNFs for different applications.

  6. Cerium Modified Pillared Montmorillonite Supported Cobalt Catalysts for Fischer Tropsch Synthesis

    International Nuclear Information System (INIS)

    Fischer-Tropsch (FT) synthesis was accomplished over Al-pillared Montmorillonite supported 20 wt% Co modified with different weight% of cerium catalysts. These catalysts were prepared by impregnation method while structural characterizations of the prepared samples were performed by XRD, TPR, NH/sub 3/TPD, TGA, BET, XRF and SEM techniques. The Fischer Tropsch reaction was studied in fixed bed micro catalytic reactor at temperature range of 220, 260 and 275 degree C and at different pressure (1, 5 and 10 bars). From the activity results, it was found that by pillaring NaMMT with Al higher catalytic activity and lower methane selectivity of NaMMT was achieved. Furthermore, the results of FT synthesis reaction revealed that cerium incorporation increased the dispersion of Co/sub 3/O/sub 4/ on the surface and consequently resulted in enhanced catalytic activity. Additionally, the C/sub 5/-C/sub 12/ hydrocarbons and methane selectivity increased while C/sub 22+/ hydrocarbons selectivity was decreased over cerium modified catalysts. Higher reaction temperature (>220 degree C) resulted in significant enhancement in CO conversion and methane selectivity. Though, increase in pressure from 1 to 10 bars eventually resulted in increase in C/sub 5+/ hydrocarbons and decrease in methane and C/sub 2/-C/sub 5/ hydrocarbons selectivity. (author)

  7. Pore curvature and support composition effects on the electronic properties of supported Pt catalysts: an infrared spectroscopy study with CO as probe molecule

    NARCIS (Netherlands)

    Lepage, M.; Visser, T.; van der Eerden, A.M.J.; Soulimani, F.; Weckhuysen, B.M.

    2008-01-01

    Supported 1 wt% Pt-based catalyst materials have been used as model systems to study pore curvature and support composition effects on the electronic properties of supported Pt nanoparticles. For this purpose, Pt nanoparticles have been loaded onto microporous (ITQ-1), mesoporous (Si- MCM-41, Si-MCM

  8. The application of inelastic neutron scattering to investigate the steam reforming of methane over an alumina-supported nickel catalyst

    Science.gov (United States)

    McFarlane, Andrew R.; Silverwood, Ian P.; Norris, Elizabeth L.; Ormerod, R. Mark; Frost, Christopher D.; Parker, Stewart F.; Lennon, David

    2013-12-01

    An alumina-supported nickel catalyst, previously used in methane reforming experiments employing CO2 as the oxidant, is applied here in the steam reforming variant of the process. Micro-reactor experiments are used to discern an operational window compatible with sample cells designed for inelastic neutron scattering (INS) experiments. INS spectra are recorded after 6 h reaction of a 1:1 mixture of CH4 and H2O at 898 K. Weak INS spectra are observed, indicating minimal hydrogen retention by the catalyst in this operational regime. Post-reaction, the catalyst is further characterised by powder X-ray diffraction, transmission electron microscopy and Raman scattering. In a comparable fashion to that seen for the ‘dry’ reforming experiments, the catalyst retains substantial quantities of carbon in the form of filamentous coke. The role for hydrogen incorporation by the catalyst is briefly considered.

  9. Novel growth method of carbon nanotubes using catalyst-support layer developed by alumina grit blasting.

    Science.gov (United States)

    Watanabe, Hiromichi; Ishii, Juntaro; Ota, Keishin

    2016-08-19

    We propose an efficient method of growing carbon nanotube (CNT) arrays on a variety of metals, alloys, and carbon materials using chemical vapor deposition (CVD) assisted by a simple surface treatment of the materials. The main feature of this method is the application of grit blasting with fine alumina particles to the development of a catalyst-support layer required for the growth of CNTs on various conductive materials, including ultra-hard metals such as tungsten. Auger electron spectroscopy shows that grit blasting can form a non-continuous layer where alumina nanoparticles are embedded as residues in the blasting media left on the treated surfaces. This work reveals that such a non-continuous alumina layer can behave as the catalyst-support layer, which is generally prepared by sputter or a vacuum evaporation coating process that considerably restricts the practical applications of CNTs. We have attempted to grow CNTs on grit-blasted substrates of eighteen conventionally used conductive materials using CVD together with a floating iron catalyst. The proposed method was successful in growing multi-walled CNT arrays on the grit-blasted surfaces of all the examined materials, demonstrating its versatility. Furthermore, we found that the group IV metal oxide films thermally grown on the as-received substrates can support the catalytic activity of iron nanoparticles in the CVD process just as well as the alumina film developed by grit blasting. Spectral emissivity of the CNT arrays in the visible and infrared wavelength ranges has been determined to assess the applicability of the CNT arrays as a black coating media. PMID:27389659

  10. Novel growth method of carbon nanotubes using catalyst-support layer developed by alumina grit blasting

    Science.gov (United States)

    Watanabe, Hiromichi; Ishii, Juntaro; Ota, Keishin

    2016-08-01

    We propose an efficient method of growing carbon nanotube (CNT) arrays on a variety of metals, alloys, and carbon materials using chemical vapor deposition (CVD) assisted by a simple surface treatment of the materials. The main feature of this method is the application of grit blasting with fine alumina particles to the development of a catalyst-support layer required for the growth of CNTs on various conductive materials, including ultra-hard metals such as tungsten. Auger electron spectroscopy shows that grit blasting can form a non-continuous layer where alumina nanoparticles are embedded as residues in the blasting media left on the treated surfaces. This work reveals that such a non-continuous alumina layer can behave as the catalyst-support layer, which is generally prepared by sputter or a vacuum evaporation coating process that considerably restricts the practical applications of CNTs. We have attempted to grow CNTs on grit-blasted substrates of eighteen conventionally used conductive materials using CVD together with a floating iron catalyst. The proposed method was successful in growing multi-walled CNT arrays on the grit-blasted surfaces of all the examined materials, demonstrating its versatility. Furthermore, we found that the group IV metal oxide films thermally grown on the as-received substrates can support the catalytic activity of iron nanoparticles in the CVD process just as well as the alumina film developed by grit blasting. Spectral emissivity of the CNT arrays in the visible and infrared wavelength ranges has been determined to assess the applicability of the CNT arrays as a black coating media.

  11. Synthesis and characterization of niobium-promoted cobalt/iron catalysts supported on carbon nanotubes for the hydrogenation of carbon monoxide

    Institute of Scientific and Technical Information of China (English)

    Zahra Gholami; Noor Asmawati Mohd Zabidi; Fatemeh Gholami; Mohammadtaghi Vakili

    2016-01-01

    Bimetallic Co/Fe catalysts supported on carbon nanotubes ( CNTs) were prepared, and niobium ( Nb) was added as promoter to the 70Co:30Fe/CNT catalyst. The physicochemical properties of the catalysts were characterized, and the catalytic performances were analyzed at the same operation conditions (H2:CO (volume ratio)= 2:1, p = 1 MPa, and t = 260℃) in a tubular fixed-bed microreactor system. The addition of Nb to the bimetallic catalyst decreases the average size of the oxide nanoparticles and improves the reducibility of the bimetallic catalyst. Evaluation of the catalyst performance in a Fischer-Tropsch reaction shows that the catalyst results in high selectivity to methane, and the selectivity to C5+ increased slightly in the bimetallic catalyst unlike that in the monometallic catalysts. The addition of 1% Nb to the bimetallic catalyst increases CO conversion and selectivity to C5+. Meanwhile, a decrease in methane selectivity is observed.

  12. 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.

  13. 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.

  14. On the preparation and characterisation of MCM-41 supported heterogeneous nickel and molybdenum catalysts

    OpenAIRE

    Lensveld, Dennis

    2003-01-01

    MCM-41 is an ordered mesoporous material, displaying a honeycomb-like structure of uniform mesopores (3 nm in diameter) running through a matrix of amorphous silica. Because of the high porosity (pore volume » 1.0 ml g-1) and concomitant large surface area (approximately 1,000 m2 g-1) MCM-41 is in principle ideally suited to be used as a support material for heterogeneous catalysts, as it offers the possibility to apply (precursors of) active phases in a highly dispersed fashion. Unfortunatel...

  15. Catalytic Combustion of Methane over Ti-Pillared Clay Supported Copper Catalysts

    Institute of Scientific and Technical Information of China (English)

    Xiufeng Xu; Yanfei Pan; Xiaoyan Cui; Zhanghuai Suo

    2004-01-01

    A natural montmorillonite, produced from Laiyang of Shandong Province, was pillared by Tipolycations to form Ti-pillared clay (Ti-PILC), and characterized by BET surface area, infrared spectra and thermal analysis. The characterization results show that Ti-PILC has a larger surface area and more hydroxyl groups than that of the natural clay, thus was used as the catalytic carriers to prepare supported Cu catalysts (Cu/Ti-PILC). The 20%Cu/Ti-PILC with 10mmol/g of Ti/clay shows a high catalytic performance of methane combustion in the temperature range of 400-500 ℃.

  16. 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.

  17. Nanocrystalline Anatase Titania Supported Vanadia Catalysts: Facet-dependent Structure of Vanadia

    Energy Technology Data Exchange (ETDEWEB)

    Li, Wei-Zhen; Gao, Feng; Li, Yan; Walter, Eric D.; Liu, Jun; Peden, Charles HF; Wang, Yong

    2015-07-09

    Titania supported vanadia, a classic heterogeneous catalyst for redox reactions, typically has nonhomogeneous vanadia species on various titania facets, making it challenging not only to determine and quantify each species but also to decouple their catalytic contributions. We prepared truncated tetragonal bipyramidal (TiO2-TTB) and rod-like (TiO2-Rod) anatase titania with only {101} and {001} facets at ratios of about 80:20 and 93:7, respectively, and used them as supports of sub-monolayer vanadia. The structure and redox properties of supported vanadia were determined by XRD, TEM, XPS, EPR, Raman, FTIR and TPR, etc. It was found that vanadia preferentially occupy TiO2 {001} facets and form isolated O=V4+(O-Ti)2 species, and with further increase in vanadia surface coverage, isolated O=V5+(O-Ti)3 and oligomerized O=V5+(O-M)3 (M = Ti or V) species form on TiO2 {101} facets. The discovery on support facet-dependent structure of vanadia on anatase titania is expected to enable the elucidation of structure-function correlations on high surface area TiO2 supported vanadia catalysts. This work was supported by U. S. Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Biosciences and Geosciences. The research was performed in the Environmental Molecular Sciences Laboratory (EMSL), a national scientific user facility sponsored by the DOE Office of Biological and Environmental Research, and located at Pacific Northwest National Laboratory (PNNL). PNNL is operated for DOE by Battelle.

  18. CuO/CeO{sub 2} catalysts prepared with different cerium supports for CO oxidation at low temperature

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Chi-Yuan [School of Public Health, Chung Shan Medical University, Taichung 402, Taiwan, ROC (China); Department of Occupational Medicine, Chung Shan Medical University Hospital, Taichung 402, Taiwan, ROC (China); Chang, Wen-Chi [Department of Environmental Engineering, National Chung Hsing University, Taichung 402, Taiwan, ROC (China); Wey, Ming-Yen, E-mail: mywey@dragon.nchu.edu.tw [Department of Environmental Engineering, National Chung Hsing University, Taichung 402, Taiwan, ROC (China)

    2013-08-15

    The activity of a catalyst depends on the nature of its support, its active site, and its preparation method. This study aimed to employ various types of CeO{sub 2} supports such as commercial CeO{sub 2} and self-prepared CeO{sub 2} for the preparation of copper catalysts. The CuO/CeO{sub 2} catalysts were prepared using the polyol process and impregnation method. The catalysts were characterized using Brunauer–Emmett–Teller analysis, scanning electron microscopy, and X-ray analysis, and their catalytic activity for CO removal was evaluated in a microcatalytic reactor. The experimental results showed that the catalytic activity of the CuO/CeO{sub 2} catalysts with different calcination temperatures decreased in the following order: 500 °C > 300 °C > 700 °C. Compared to the impregnation method, the polyol process generated well-dispersed metal particles over the support and showed higher CO removal efficiency with low activation energy. Compared to CuO/CeO{sub 2} catalysts with commercial CeO{sub 2}, those with CeO{sub 2} that was self-prepared by pyrolysis had a large pore volume and good crystal structure of CeO{sub 2} and showed good performance. The catalytic activity for CO removal was in the following order: CuO/CeO{sub 2}-P (pyrolysis) > CuO/CeO{sub 2}-C (commercial) > CuO/CeO{sub 2}-D (deposition precipitation). CuO/CeO{sub 2}-P catalysts showed good activity even at low temperature. The CuO/CeO{sub 2}-P(300)-P-120 min catalyst was found to possess the good CO removal rate when the oxygen content was 6%, CO concentration was 500 ppm, catalyst weighed 1.0 g, pollutant gas velocity was 500 mL min{sup −1}, SV was 3.7 × 10{sup 4} h{sup −1}, and reaction temperature was 150 °C. - Highlights: • CuO/CeO{sub 2} catalysts were prepared using polyol and impregnation methods. • The supports of catalyst were self-prepared cerium oxide and commercial cerium oxide. • Pyrolysis and deposition precipitation methods were used for cerium preparation.

  19. Simultaneous catalytic removal of NOx and diesel soot particulate over perovskite-type oxides and supported Ag catalysts

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A series of perovskite-type oxides and supported Ag catalysts were prepared,and characterized by X-ray diffraction (XRD) and Xray photoelectron spectroscopy (XPS).The catalytic activities of the catalysts as well as influencing factors on catalytic activity have been investigated for the simultaneous removal of NOx and diesel soot particulate.An increase in catalytic activity for the selective reduction of NOx was observed with Ag addition in these perovskite oxides,especially with 5% Ag loading.This catalyst could be a promising candidate of catalytic material for the simultaneous elimination of NOx and diesel soot.

  20. Studies on Zeolite-Supported Mo and Re Catalysts : Catalytic Performance in Methane Aromatization Reaction and Their Structural Characterization

    OpenAIRE

    Wang, Linsheng

    1999-01-01

    The main achievements in the present studies are summarized as 4 key points: 1) HZSM-5 supported Mo and Re catalysts are found to be quite active and selective for directly conyerting methane to benzene, naphthalene and C2 hydrocarbons. A great progress for methane aromatization has been made because of the discover of the two new catalysts. 2) Coke deposition on the catalyst for non-oxidative conversion of methane is solved by varying methane pressure combined with addition of CO2 in methane...

  1. Controlled radical polymerization of vinyl acetate in presence of mesoporous silica supported TiCl4 heterogeneous catalyst

    Indian Academy of Sciences (India)

    M A Semsarzadeh; S Amiri; M Azadeh

    2012-10-01

    The heterogeneous TiCl4 catalysts supported on mesoporous mobile composition of matter (MCM-41) and mesoporous silicone particles synthesized from block copolymer of PPG–PEG–PPG (SPB) complexed with dimethyl formamide (DMF) ligand were used in a controlled free radical reaction with benzoyl peroxide (BPO) initiator in bulk polymerization of vinyl acetate (VAc). In this polymerization process, mesoporous particle of SPB increased the reactivity of TiCl4 catalyst with DMF ligand. The active site formed on the surface and the pores of the catalyst produced specific sequences of VAc on the chain with different thermal and microstructural properties and crystallinity.

  2. 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...... activity at atmospheric pressure in the temperature range 250–600 °C. The SO2 to SO3 conversion efficiency of the Pt–Pd alloy was significantly higher than that of the individual metals. The effects of the preparation method and the titania type used on the properties and activity of the resulting catalyst...

  3. Catalytic Transfer Hydrogenation of Furfural to Furfuryl Alcohol over Nitrogen-Doped Carbon-Supported Iron Catalysts.

    Science.gov (United States)

    Li, Jiang; Liu, Jun-Ling; Zhou, Hong-Jun; Fu, Yao

    2016-06-01

    Iron-based heterogeneous catalysts, which were generally prepared by pyrolysis of iron complexes on supports at elevated temperature, were found to be capable of catalyzing the transfer hydrogenation of furfural (FF) to furfuryl alcohol (FFA). The effects of metal precursor, nitrogen precursor, pyrolysis temperature, and support on catalytic performance were examined thoroughly, and a comprehensive study of the reaction parameters was also performed. The highest selectivity of FFA reached 83.0 % with a FF conversion of 91.6 % under the optimal reaction condition. Catalyst characterization suggested that iron cations coordinated by pyridinic nitrogen functionalities were responsible for the enhanced catalytic activity. The iron catalyst could be recycled without significant loss of catalytic activity for five runs, and the destruction of the nitrogen-iron species, the presence of crystallized Fe2 O3 phase, and the pore structure change were the main reasons for catalyst deactivation. PMID:27144965

  4. Nickel catalysts supported on MgO with different specific surface area for carbon dioxide reforming of methane

    Institute of Scientific and Technical Information of China (English)

    Luming; Zhang; Lin; Li; Yuhua; Zhang; Yanxi; Zhao; Jinlin; Li

    2014-01-01

    In this paper, three kinds of MgO with different specific surface area were prepared, and their effects on the catalytic performance of nickel catalysts for the carbon dioxide reforming of methane were investigated. The results showed that MgO support with the higher specific surface area led to the higher dispersion of the active metal, which resulted in the higher initial activity. On the other hand, the specific surface area of MgO materials might not be the dominant factor for the basicity of support to chemisorb and activate CO2, which was another important factor for the performance of catalysts. Herein, Ni/MgO(CA) catalyst with proper specific surface area and strong ability to activate CO2exhibited stable catalytic property and the carbon species deposited on the Ni/MgO(CA) catalyst after 10 h of reaction at 650 ?C were mainly activated carbon species.

  5. Heterogeneous catalytic ozonation of ciprofloxacin in water with carbon nanotube supported manganese oxides as catalyst

    International Nuclear Information System (INIS)

    Highlights: ► Ciprofloxacin in water was degraded by heterogeneous catalytic ozonation. ► MnOx were supported on MWCNTs to serve as catalyst for ozonation. ► MnOx/MWCNT exhibited highly catalytic activity on ozonation of ciprofloxacin in water. ► MnOx/MWCNT resulted in effective antibacterial activity inhibition on ciprofloxacin. ► MnOx/MWCNT promoted the generation of hydroxyl radicals. - Abstract: Carbon nanotube-supported manganese oxides (MnOx/MWCNT) were used as catalysts to assist ozone in degrading ciprofloxacin in water. Manganese oxides were successfully loaded on multi-walled carbon nanotube surfaces by simply impregnating the carbon nanotube with permanganate solution. The catalytic activities of MnOx/MWCNT in ciprofloxacin ozonation, including degradation, mineralization effectiveness, and antibacterial activity change, were investigated. The presence of MnOx/MWCNT significantly elevated the degradation and mineralization efficiency of ozone on ciprofloxacin. The microbiological assay with a reference Escherichia coli strain indicated that ozonation with MnOx/MWCNT results in more effective antibacterial activity inhibition of ciprofloxacin than that in ozonation alone. The effects of catalyst dose, initial ciprofloxacin concentration, and initial pH conditions on ciprofloxacin ozonation with MnOx/MWCNT were surveyed. Electron spin resonance trapping was applied to assess the role of MnOx/MWCNT in generating hydroxyl radicals (HO·) during ozonation. Stronger 5,5-dimethyl-1-pyrroline-N-oxide–OH signals were observed in the ozonation with MnOx/MWCNT compared with those in ozonation alone, indicating that MnOx/MWCNT promoted the generation of hydroxyl radicals. The degradation of ciprofloxacin was studied in drinking water and wastewater process samples to gauge the potential effects of water background matrix on MnOx/MWCNT catalytic ozonation.

  6. Heterogeneous catalytic ozonation of ciprofloxacin in water with carbon nanotube supported manganese oxides as catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Sui, Minghao, E-mail: suiminghao.sui@gmail.com [State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092 (China); Xing, Sichu; Sheng, Li; Huang, Shuhang; Guo, Hongguang [State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092 (China)

    2012-08-15

    Highlights: Black-Right-Pointing-Pointer Ciprofloxacin in water was degraded by heterogeneous catalytic ozonation. Black-Right-Pointing-Pointer MnOx were supported on MWCNTs to serve as catalyst for ozonation. Black-Right-Pointing-Pointer MnOx/MWCNT exhibited highly catalytic activity on ozonation of ciprofloxacin in water. Black-Right-Pointing-Pointer MnOx/MWCNT resulted in effective antibacterial activity inhibition on ciprofloxacin. Black-Right-Pointing-Pointer MnOx/MWCNT promoted the generation of hydroxyl radicals. - Abstract: Carbon nanotube-supported manganese oxides (MnOx/MWCNT) were used as catalysts to assist ozone in degrading ciprofloxacin in water. Manganese oxides were successfully loaded on multi-walled carbon nanotube surfaces by simply impregnating the carbon nanotube with permanganate solution. The catalytic activities of MnOx/MWCNT in ciprofloxacin ozonation, including degradation, mineralization effectiveness, and antibacterial activity change, were investigated. The presence of MnOx/MWCNT significantly elevated the degradation and mineralization efficiency of ozone on ciprofloxacin. The microbiological assay with a reference Escherichia coli strain indicated that ozonation with MnOx/MWCNT results in more effective antibacterial activity inhibition of ciprofloxacin than that in ozonation alone. The effects of catalyst dose, initial ciprofloxacin concentration, and initial pH conditions on ciprofloxacin ozonation with MnOx/MWCNT were surveyed. Electron spin resonance trapping was applied to assess the role of MnOx/MWCNT in generating hydroxyl radicals (HO{center_dot}) during ozonation. Stronger 5,5-dimethyl-1-pyrroline-N-oxide-OH signals were observed in the ozonation with MnOx/MWCNT compared with those in ozonation alone, indicating that MnOx/MWCNT promoted the generation of hydroxyl radicals. The degradation of ciprofloxacin was studied in drinking water and wastewater process samples to gauge the potential effects of water background matrix on

  7. NO oxidation on Zeolite Supported Cu Catalysts: Formation and Reactivity of Surface Nitrates

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Hai-Ying; Wei, Zhehao; Kollar, Marton; Gao, Feng; Wang, Yilin; Szanyi, Janos; Peden, Charles HF

    2016-04-18

    The comparative activities of a small-pore Cu-CHA and a large-pore Cu-BEA catalyst for the selective catalytic reduction (SCR) of NOx with NH3, and for the oxidation of NO to NO2 and the subsequent formation of surface nitrates were investigated. Although both catalysts are highly active in SCR reactions, they exhibit very low NO oxidation activity. Furthermore, Cu-CHA is even less active than Cu-BEA in catalyzing NO oxidation but is clearly more active for SCR reactions. Temperature-programed desorption (TPD) experiments following the adsorption of (NO2 + NO + O2) with different NO2:NO ratios reveal that the poor NO oxidation activity of the two catalysts is not due to the formation of stable surface nitrates. On the contrary, NO is found to reduce and decompose the surface nitrates on both catalysts. To monitor the reaction pathways, isotope exchange experiments were conducted by using 15NO to react with 14N-nitrate covered catalyst surfaces. The evolution of FTIR spectra during the isotope exchange process demonstrates that 14N-nitrates are simply displaced with no formation of 15N-nitrates on the Cu-CHA sample, which is clearly different from that observed on the Cu-BEA sample where formation of 15N-nitrates is apparent. The results suggest that the formal oxidation state of N during the NO oxidation on Cu-CHA mainly proceeds from its original +2 to a +3 oxidation state, whereas reaching a higher oxidation state for N, such as +4 or +5, is possible on Cu-BEA. The authors at PNNL gratefully acknowledge the US Department of Energy (DOE), Energy Efficiency and Renewable Energy, Vehicle Technologies Office for the support of this work. The research described in this paper was performed at the Environmental Molecular Sciences Laboratory (EMSL), a national scientific user facility sponsored by the DOE’s Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory (PNNL). PNNL is operated for the US DOE by Battelle.

  8. Oxygen-deficient titania as alternative support for Pt catalysts for the oxygen reduction reaction

    Institute of Scientific and Technical Information of China (English)

    Anqi Zhao; Justus Masa; Wei Xia

    2014-01-01

    Insufficient electrochemical stability is a major challenge for carbon materials in oxygen reduction reaction (ORR) due to carbon corrosion and insufficient metal-support interactions. In this work, titania is explored as an alternative support for Pt catalysts. Oxygen deficient titania samples including TiO2−x and TiO2−xNy were obtained by thermal treatment of anatase TiO2 under flowing H2 and NH3, respectively. Pt nanoparticles were deposited on the titania by a modified ethylene glycol method. The samples were characterized by N2-physisorption, X-ray diffraction and X-ray photoelectron spectroscopy. The ORR activity and long-term stability of supported Pt catalysts were evaluated using linear sweep voltammetry and chronoamperometry in 0.1 mol/L HClO4. Pt/TiO2−x and Pt/TiO2−xNy showed higher ORR activities than Pt/TiO2 as indicated by higher onset potentials. Oxygen deficiency in TiO2−x and TiO2−xNy contributed to the high ORR activity due to enhanced charge transfer, as disclosed by electrochemical impedance spectroscopy studies. Electrochemical stability studies revealed that Pt/TiO2−x exhibited a higher stability with a lower current decay rate than commercial Pt/C, which can be attributed to the stable oxide support and strong interaction between Pt nanoparticles and the oxygen-deficient TiO2−x support.

  9. 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

  10. Mechanistic understanding and kinetic studies of highly selective oxidative dehydrogenation of ethane over novel supported molten chloride catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Gaertner, C.; Veen, A.C. van; Lercher, J.A. [Technische Univ. Muenchen, Garching (Germany). Dept. of Chemistry

    2012-07-01

    Ethene is one of the most important feedstocks for chemical industry, nowadays mainly produced via steam cracking. However, oxidative dehydrogenation becomes a more important process route, allowing to produce ethene selectively and at lower temperatures. Supported alkali chloride catalysts are promising materials. However, the ODH mechanism of this class of catalysts is not well investigated so far. The investigation of the reaction mechanism is thus the aim of this contribution. (orig.)

  11. Enhanced stability of multilayer graphene-supported catalysts for polymer electrolyte membrane fuel cell cathodes

    Science.gov (United States)

    Marinkas, A.; Hempelmann, R.; Heinzel, A.; Peinecke, V.; Radev, I.; Natter, H.

    2015-11-01

    One of the biggest challenges in the field of polymer electrolyte membrane fuel cells (PEMFC) is to enhance the lifetime and the long-term stability of PEMFC electrodes, especially of cathodes, furthermore, to reduce their platinum loading, which could lead to a cost reduction for efficient PEMFCs. These demands could be achieved with a new catalyst support architecture consisting of a composite of carbon structures with significant different morphologies. A highly porous cathode catalyst support layer is prepared by addition of various carbon types (carbon black particles, multi-walled carbon nanotubes (MWCNT)) to multilayer graphene (MLG). The reported optimized cathodes shows extremely high durability and similar performance to commercial standard cathodes but with 89% lower Pt loading. The accelerated aging protocol (AAP) on the membrane electrode assemblies (MEA) shows that the presence of MLG increases drastically the durability and the Pt-extended electrochemical surface area (ECSA). In fact, after the AAP slightly enhanced performance can be observed for the MLG-containing cathodes instead of a performance loss, which is typical for the commercial carbon-based cathodes. Furthermore, the presence of MLG drastically decreases the ECSA loss rate. The MLG-containing cathodes show up to 6.8 times higher mass-normalized Pt-extended ECSA compared to the commercial standard systems.

  12. Nanoparticles of TiAlZr mixed oxides as supports of hydrodesulfurization catalysts: Synthesis and characterization

    Energy Technology Data Exchange (ETDEWEB)

    Kraleva, E., E-mail: ekraleva@gmail.com [Institute of Biodiversity and Ecosystems Research, Bulgarian Academy of Sciences, Sofia, Gagarin st.2 (Bulgaria); Spojakina, A. [Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria); Saladino, M.L. [Dipartimento di Chimica ' S. Cannizzaro' , Universita di Palermo and INSTM-Udr Palermo, Parco d' Orleans II Viale delle Scienze pad 17, I-90128 Palermo,Italy (Italy); Caponetti, E. [Dipartimento di Chimica ' S. Cannizzaro' , Universita di Palermo and INSTM-Udr Palermo, Parco d' Orleans II Viale delle Scienze pad 17, I-90128 Palermo,Italy (Italy); Centro Grandi Apparecchiature - UniNetLab, Universita di Palermo, Via F. Marini 14, I-90128 Palermo (Italy); Nasillo, G. [Centro Grandi Apparecchiature - UniNetLab, Universita di Palermo, Via F. Marini 14, I-90128 Palermo (Italy); Jiratova, K. [Institute of Chemical Process Fundamentals, 16502 Prague 6 (Czech Republic)

    2012-02-05

    Highlights: Black-Right-Pointing-Pointer Preparation of ternary mixed oxide by sol-gel method. Black-Right-Pointing-Pointer Catalytic properties of the three-mixed oxides. Black-Right-Pointing-Pointer Heteropolyacid H{sub 3}PMo{sub 12}O{sub 40} and its cobalt salt Co{sub 1.5}PMo{sub 12}O{sub 40} that of active components in catalytic systems for thiophene hydrodesulfurization (HDS). - Abstract: TiAlZr mixed oxides, synthesized using sol-gel method, were characterized and used as supports of hydrodesulfurization catalysts (12 wt% Mo) prepared by impregnation either with molybdenum heteropolyacid H{sub 3}PMo{sub 12}O{sub 40} or its cobalt salt Co{sub 1.5}PMo{sub 12}O{sub 40}. Structure, morphology and textural properties of oxides and catalysts were characterized using X-ray powder diffraction (XRD), Raman spectroscopy, Nitrogen adsorption porosimetry, TEM-EDS, temperature-programmed desorption (TPD) and temperature-programmed reduction (TPR) techniques. Activity of the catalytic systems was tested in thiophene hydrodesulfurization (HDS). No formation of a new oxide phase was revealed in the synthesized mixed materials. However the effect of separated oxides on the structure of ternary oxides was observed. Maximum in HDS activity of Mo containing samples was determined by optimum content of alumina in the mixed oxides. Incorporation of cobalt into the heteropolyacid increased the HDS activity about two times and masked the effect of the support composition.

  13. Nanoparticles of TiAlZr mixed oxides as supports of hydrodesulfurization catalysts: Synthesis and characterization

    International Nuclear Information System (INIS)

    Highlights: ► Preparation of ternary mixed oxide by sol–gel method. ► Catalytic properties of the three-mixed oxides. ► Heteropolyacid H3PMo12O40 and its cobalt salt Co1.5PMo12O40 that of active components in catalytic systems for thiophene hydrodesulfurization (HDS). - Abstract: TiAlZr mixed oxides, synthesized using sol–gel method, were characterized and used as supports of hydrodesulfurization catalysts (12 wt% Mo) prepared by impregnation either with molybdenum heteropolyacid H3PMo12O40 or its cobalt salt Co1.5PMo12O40. Structure, morphology and textural properties of oxides and catalysts were characterized using X-ray powder diffraction (XRD), Raman spectroscopy, Nitrogen adsorption porosimetry, TEM-EDS, temperature-programmed desorption (TPD) and temperature-programmed reduction (TPR) techniques. Activity of the catalytic systems was tested in thiophene hydrodesulfurization (HDS). No formation of a new oxide phase was revealed in the synthesized mixed materials. However the effect of separated oxides on the structure of ternary oxides was observed. Maximum in HDS activity of Mo containing samples was determined by optimum content of alumina in the mixed oxides. Incorporation of cobalt into the heteropolyacid increased the HDS activity about two times and masked the effect of the support composition.

  14. Decomposition of hexachlorobenzene over Al2O3 supported metal oxide catalysts

    Institute of Scientific and Technical Information of China (English)

    ZHANG Lifei; ZHENG Minghui; ZHANG Bing; LIU Wenbin; GAO Lirong; BA Te; REN Zhiyuan; SU Guijin

    2008-01-01

    Decomposition of hexachlorobenzene (HCB) was investigated over several metal oxides (i.e., MgO, CaO, BaO, La2O3,CeO2, MnO2, Fe2O3 and Co3O4) supported on Al2O3, which was achieved in closed system at a temperature of 300℃. Catalysts were prepared by incipient wetness impregnation with different metal oxides loading and impregnating solvents. The decomposition efficiency of different catalysts for this reaction depends on the nature of the metal oxide used, and Al2O3 supported La2O3 was found to be the most active one. Pentachlorobenzene (PeCB), and all tetrachlorobenzene (TeCB), trichlorobenzene (TrCB), and dichlorobenzene (DCB) isomers were detected after the decomposition reaction, indicating that the decomposition was mainly a dechlorination process. The detection of all lower chlorinated beazenes suggested the complexity of decomposition and the presence of more than one dechlodnation pathway.

  15. Novel MWCNT-Support for Co-Mo Sulfide Catalyst in HDS of Thiophene and HDN of Pyrrole

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    With home-made multi-walled carbon nanotubes (MWCNTs, simplified as CNTs in later text) as support, CNT-supported Co-Mo-S catalysts, denoted as x%(mass percentage)MoiCoj/CNTs,were prepared. Their catalytic performance for thiophene hydrodesulfurization (HDS) and pyrrole hydrodenitrification (HDN) reactions was studied, and compared with the reference system supported by AC. Over the 7.24%Mo3Co1/CNTs catalyst at reaction condition of 1.5 MPa, 613 K,C4H4S/H2 =3.7/96.3(molar ratio) and GHSV≈8000 mlSTP/(g-cat.h), the specific HDS activity of thiophene the AC-based counterpart, and was 2.47 times as high as that (1.33 mmolC4H4S/(s.molMo)) of the catalysts supported by AC with the respective optimal Mo3Co1-loading amount, 16.90%Mo3Co1/AC. Analogous reaction-chemical behaviours were also observed in the case of pyrrole HDN. It was experimentally found that using the CNTs in place of AC as support of the catalyst caused little change in the apparent activation energy for the thiophene HDS or pyrrole HDN reaction, but led to a significant increase in the concentration of catalytically active Mo-species (Mo4+) at the surface of the functioning catalyst. On the other hand, H2-TPD measurements revealed that the CNT-supported catalyst could reversibly adsorb a greater amount of hydrogen under atmospheric pressure at temperatures ranging from room temperature to about 673 K. This unique feature would help to generate microenvironments with higher stationarystate concentration of active hydrogen-adspecies at the surface of the functioning catalyst. Both factors mentioned above were favorable to increasing the rate of thiophene HDS and pyrrole HDN reactions.

  16. 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.

  17. Effect of composite supports on the methanation activity of Co-Mo-based sulphur-resistant catalysts

    Institute of Scientific and Technical Information of China (English)

    Haiyang Wang; Zhenhua Li; Erdong Wang; Can Lin; Yuguang Shang; Guozhong Ding; Xinbin Ma; Shaodong Qin; Qi Sun

    2012-01-01

    The effects of composite supports of CeO2-Al2O3,MgO-Al2O3,TiO2-Al2O3 or ZrO2-Al2O3 on the methanation activity of supported CoMo-based sulphur-resistant catalysts were investigated.The catalysts were further characterized by nitrogen adsorption measurement,X-ray diffraction and X-ray photoelectron spectroscopy.The catalyst of 5%CoO-15%MoO3 supported on CeO2-Al2O3,MgO-Al2O3,TiO2-Al2O3 or ZrO2-Al2O3 composite oxides,respectively,showed different catalytic performances of syngas methanation in the presence of hydrogen sulphide as compared with that of the 5%CoO-15%MoO3/Al2O3 catalyst.The Co-Mo/CeO2-Al2O3 catalyst shows the highest methanation activity among the tested catalysts.The enhanced methanation activity may be attributed to the improvement of the dispersion of active metal species and the inhibition of the formation of S6+.

  18. In situ adsorption-catalysis system for the removal of o-xylene over an activated carbon supported Pd catalyst

    Institute of Scientific and Technical Information of China (English)

    HUANG Shaoyong; ZHANG Changbin; HE Hong

    2009-01-01

    An activated carbon (AC) supported Pd catalyst was used to develop a highly efficient in situ adsorption-catalysis system for the removal of low concentrations of o-xylene. In this study, three kinds of Pd/AC catalysts were prepared and tested to investigate the synergistic efficiency between adsorption and catalysis for o-xylene removal. The Pd/AC catalyst was first used as an adsorbent to concentrate dilute o-xylene at low temperature. After saturated adsorption, the adsorbed o-xylene was oxidized to CO2 and H2O by raising the temperature of the catalyst bed. The results showed that more than 99% of the adsorbed o-xylene was completely oxidized to CO2 over a 5% Pd/AC catalyst at 140℃. Brunauer-Emmett-Teller (BET) analysis, scanning electron microscopy (SEM), temperature-programmed desorption (TPD), and temperature-programmed oxidation (TPO) were applied to investigate the physical properties of o-xylene adsorption-desorption and the in situ adsorption-catalysis activity of the AC support and Pd/AC catalyst. A synergistic relationship between the AC support and the active Pd species for the removal of low concentrations of o-xylene was established.

  19. Characterization and reactivity of 11-molybdo-1-vanadophosphoric acid catalyst supported on zirconia for dehydration of glycerol to acrolein

    Indian Academy of Sciences (India)

    Balaga Viswanadham; Amirineni Srikanth; Komandur V R Chary

    2014-03-01

    A series of vanadium-substituted phosphomolybdic acid (HPA) catalysts supported on zirconia were prepared by impregnation method with varying the HPA active phase content from 10 to 50 wt% on the support. The calcined catalysts were characterized by X-ray diffraction, Raman spectroscopy, temperatureprogrammed desorption of NH3, FT-IR spectra of pyridine adsorption and surface area measurements. XRD results suggest that the active phase of heteropolyacid is present in a highly dispersed state at lower loadings and as a crystalline phase at higher HPA loadings and these findings are well-supported by the results of FT-IR and Raman spectra. Calcination of the samples did not affect the Keggin ion structure of HPA. The ammonia TPD results suggest that acidity of the catalysts was found to increase with increase of HPA loading up to 40 wt% and decreases at higher loadings. FT-IR spectra of pyridine adsorption show that the Brønsted acidic sites increase with increase of HPA loadings up to 40 wt% catalyst. However, Lewis acid sites decrease with increase ofHPA loading. Catalytic properties were evaluated during vapour phase dehydration of glycerol to acrolein. The catalyst with 40 wt% HPA has exhibited excellent selectivity towards acrolein formation with complete conversion of glycerol at 225°C under atmospheric pressure. Catalytic performances during dehydration of glycerol are well-correlated with acidity of the catalysts.

  20. Selective CO Methanation on Ru/TiO2 Catalysts: Role and Influence of Metal-Support Interactions

    DEFF Research Database (Denmark)

    Abdel-Mageed, Ali M.; Widmann, D.; Olesen, Sine Ellemann;

    2015-01-01

    Aiming at a detailed understanding of the role of metal-support interactions in the selective methanation of CO in CO2-rich reformate gases, we have investigated the catalytic performance of a set of Ru/TiO2 catalysts with comparable Ru loading, Ru particle size, and TiO2 phase composition but very...... with a surface area of 121 m2 g-1 and then decreasing for an even higher surface area; however, the selectivity is mainly determined by the Ru particle size, which slightly decreases with increasing support surface area. This goes along with an increase in selectivity for CO methanation, in agreement...... with a model proposed previously for nonreducible supports. In situ infrared measurements further revealed that also the adsorption properties for these catalysts, as evidenced by the CO adsorption strength, change significantly with increasing catalyst surface area and that strong metal-support interactions...

  1. Ceria maintains smaller metal catalyst particles by strong metal-support bonding.

    Science.gov (United States)

    Farmer, Jason A; Campbell, Charles T

    2010-08-20

    The energies of silver (Ag) atoms in Ag nanoparticles supported on different cerium and magnesium oxide surfaces, determined from previous calorimetric measurements of metal adsorption energies, were analyzed with respect to particle size. Their stability was found to increase with particle size below 5000 atoms per particle. Silver nanoparticles of any given size below 1000 atoms had much higher stability (30 to 70 kilojoules per mole of silver atoms) on reduced CeO2(111) than on MgO(100). This effect is the result of the very large adhesion energy (approximately 2.3 joules per square meter) of Ag nanoparticles to reduced CeO2(111), which we found to be a result of strong bonding to both defects and CeO2(111) terraces, apparently localized by lattice strain. These results explain the unusual sinter resistance of late transition metal catalysts when supported on ceria. PMID:20724631

  2. Supported catalysts based on layered double hydroxides for catalytic oxidation and hydrogenation: general functionality and promising application prospects.

    Science.gov (United States)

    Feng, Junting; He, Yufei; Liu, Yanan; Du, Yiyun; Li, Dianqing

    2015-08-01

    Oxidation and hydrogenation catalysis plays a crucial role in the current chemical industry for the production of key chemicals and intermediates. Because of their easy separation and recyclability, supported catalysts are widely used in these two processes. Layered double hydroxides (LDHs) with the advantages of unique structure, composition diversity, high stability, ease of preparation and low cost have shown great potential in the design and synthesis of novel supported catalysts. This review summarizes the recent progress in supported catalysts by using LDHs as supports/precursors for catalytic oxidation and hydrogenation. Particularly, partial hydrogenation of acetylene, hydrogenation of dimethyl terephthalate, methanation, epoxidation of olefins, elimination of NOx and SOx emissions, and selective oxidation of biomass have been chosen as representative reactions in the petrochemical, fine chemicals, environmental protection and clean energy fields to highlight the potential application and the general functionality of LDH-based catalysts in catalytic oxidation and hydrogenation. Finally, we concisely discuss some of the scientific challenges and opportunities of supported catalysts based on LDH materials. PMID:25962432

  3. 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.

  4. 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.

  5. 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

  6. Silica (NPs) supported Fe (III) as a reusable heterogeneous catalyst for the one-pot synthesis of 1, 4-dihydropyridines under mild conditions

    Indian Academy of Sciences (India)

    Javad Safaei-Ghomi; Abolfazl Ziarati; Safura Zahedi

    2012-07-01

    A cheap and recyclable silica (NPs) supported Fe (III) was prepared as heterogeneous catalyst for the synthesis of various substituted 1,4-dihydropyridines via condensation of aldehydes with ethyl acetoacetate and ammonium acetate in ethanol. The products were separated from the catalyst simply by filtration and the catalyst could be recycled and reused for several times without noticeable decrease in the catalytic activity.

  7. 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.

  8. Catalytic performance of cement clinker supported nickel catalyst in glycerol dry reforming

    Institute of Scientific and Technical Information of China (English)

    Hua Chyn Lee; Kah Weng Siew; Maksudur R. Khan; Sim Yee Chin; Jolius Gimbun; Chin Kui Cheng

    2014-01-01

    The paper reports the development of cement clinker-supported nickel (with metal loadings of 5 wt%, 10 wt%, 15 wt%and 20 wt%) catalysts for glycerol dry (CO2) reforming reaction. XRF results showed that CaO constituted 62.0%of cement clinker. The physicochemical character-ization of the catalysts revealed 32-folds increment of BET surface area (SBET) with the addition of nickel metal into the cement clinker, which was also corroborated by FESEM images. Significantly, XRD results suggested different types of Ni oxides formation with Ni loading, whilst Ca3SiO5 and Ca2Al0.67Mn0.33FeO5 were the main crystallite species for pure cement clinker. Temperature-programmed reduction analysis yielded three domains of H2 reduction peaks, viz. centered at approximately 750 K referred to as type-I peaks, another peaks at 820 K denoted as type-II peaks and the highest reduction peaks, type-III recorded at above 1000 K. 20 wt%Ni was found to be the best loading with the highest XG and H2 yield, whilst the lowest methanation activity. Syngas with lower H2/CO ratios (0.6 to 1.5) were readily produced from glycerol dry reforming at CO2-to-Glycerol feed ratio (CGR) of unity. Nonetheless, carbon deposit comprised of whisker type (Cv) and graphitic-like type (Cc) species were found to be in majority on 20 wt%Ni/CC catalysts.

  9. Hydrogenation of CO and CO2 over rhodium catalysts supported on various metal oxides

    International Nuclear Information System (INIS)

    The formation of hydrocarbons in the reaction of CO + H2 and CO2 + H2 was studied over rhodium catalysts supported on ZrO2, Al2O3, SiO2, and MgO. Among those catalysts, Rh on ZrO2 was most active and Rh-MgO was least active for the above reactions. Over Rh-ZrO2, the CO2 + H2 reaction took place even at 500C, whereas the CO + H2 reaction occurred only at temperature higher than 1300C. The reaction of CO2 + H2 produced only methane at temperatures up to 2000C, but a small amount of CO formed along with methane in the reverse water gas shift reaction above 2000C. In the case of the CO + H2 reaction, the higher molecular weight hydrocarbons (C2 approx. C4) as well as CH4 formed. The inverse kinetic isotope effect was observed in both reactions of CO + H2(D2) and CO2 + H2(D2) over Rh-ZrO2. However, the isotope effect was not observed in the CO2 + H2(D2) reaction over Rh-Al2O3 whose effect in the CO + H2 reaction was still inverse. The activity for the CO + H2 reaction over the oxidized Rh-ZrO2 and Rh-Al2O3 was almost 2 to 10 times higher than that on the reduced catalyst. The reaction mechanisms of the above reactions are discussed. 2 figures, 4 tables

  10. Hydrogenation of Liquid Styrene by Alumina Supported Nickel Catalysts: Comparison between Classical and Non-Classical Methods

    Science.gov (United States)

    Tan, Y. C.; Abu Bakar, N. H. H.; Tan, W. L.; Abu Bakar, M.

    2016-06-01

    Almina supported Ni catalysts (Ni/Al2O3) with different Ni weight percentages (wt%) were prepared via classical and non-classical methods. All samples were prepared via impregnation technique. The samples prepared via non-classical methods were reduced using KBH4 as the reducing agent. The catalysts were tested for the hydrogenation of styrene in liquid phase. Optimum activation conditions for the hydrogenation reaction were found to be 633 K for 2 hours. Comparison of the catalytic reactivity for all catalysts at these activation conditions showed that catalysts prepared via classical methods exhibited better activity. Furthermore the 7.6wt% Ni-Al2O3/C showed enhanced activity when compared to the 5.9wt% and 13.8wt% Ni-Al2O3/C catalyst. This phenomenon is mainly attributed to the type of Ni active sites available on the catalyst. The surface properties of the catalysts investigated via H2- temperature programmed reduction (H2-TPR), H2-chemisorption and H2-temperature programmed desorption (H2-TPD) confirm this.

  11. The application of inelastic neutron scattering to investigate the steam reforming of methane over an alumina-supported nickel catalyst

    International Nuclear Information System (INIS)

    Highlights: • Inelastic neutron scattering has been used to investigate a Ni/alumina catalyst. • The extent of hydrogen retention by the catalyst has been determined. • Filamentous carbon is identified as a by-product. - Abstract: An alumina-supported nickel catalyst, previously used in methane reforming experiments employing CO2 as the oxidant, is applied here in the steam reforming variant of the process. Micro-reactor experiments are used to discern an operational window compatible with sample cells designed for inelastic neutron scattering (INS) experiments. INS spectra are recorded after 6 h reaction of a 1:1 mixture of CH4 and H2O at 898 K. Weak INS spectra are observed, indicating minimal hydrogen retention by the catalyst in this operational regime. Post-reaction, the catalyst is further characterised by powder X-ray diffraction, transmission electron microscopy and Raman scattering. In a comparable fashion to that seen for the ‘dry’ reforming experiments, the catalyst retains substantial quantities of carbon in the form of filamentous coke. The role for hydrogen incorporation by the catalyst is briefly considered

  12. The application of inelastic neutron scattering to investigate the steam reforming of methane over an alumina-supported nickel catalyst

    Energy Technology Data Exchange (ETDEWEB)

    McFarlane, Andrew R.; Silverwood, Ian P. [School of Chemistry, Joseph Black Building, University of Glasgow, Glasgow G12 8QQ (United Kingdom); Norris, Elizabeth L.; Ormerod, R. Mark [Department of Chemistry, School of Physical and Geographical Sciences, Keele University, Staffs ST5 5BG (United Kingdom); Frost, Christopher D.; Parker, Stewart F. [ISIS Facility, STFC Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX (United Kingdom); Lennon, David, E-mail: David.Lennon@glasgow.ac.uk [School of Chemistry, Joseph Black Building, University of Glasgow, Glasgow G12 8QQ (United Kingdom)

    2013-12-12

    Highlights: • Inelastic neutron scattering has been used to investigate a Ni/alumina catalyst. • The extent of hydrogen retention by the catalyst has been determined. • Filamentous carbon is identified as a by-product. - Abstract: An alumina-supported nickel catalyst, previously used in methane reforming experiments employing CO{sub 2} as the oxidant, is applied here in the steam reforming variant of the process. Micro-reactor experiments are used to discern an operational window compatible with sample cells designed for inelastic neutron scattering (INS) experiments. INS spectra are recorded after 6 h reaction of a 1:1 mixture of CH{sub 4} and H{sub 2}O at 898 K. Weak INS spectra are observed, indicating minimal hydrogen retention by the catalyst in this operational regime. Post-reaction, the catalyst is further characterised by powder X-ray diffraction, transmission electron microscopy and Raman scattering. In a comparable fashion to that seen for the ‘dry’ reforming experiments, the catalyst retains substantial quantities of carbon in the form of filamentous coke. The role for hydrogen incorporation by the catalyst is briefly considered.

  13. Effects of preparation methods of support on the properties of nickel catalyst for hydrogenation of m-dinitrobenzene

    Institute of Scientific and Technical Information of China (English)

    LIU Yingxin; WEI Zuojun; CHEN Jixiang; ZHANG Jiyan

    2007-01-01

    Using tetraethyl orthosilicate(TEOS) as the precursor of silica,the silica aerogel and xerogel,which were used as supports of nickel-based catalysts for liquid hydrogenation of m-dinitrobenzene to m-phenylenediamine,were prepared by the sol-gel method combined with supercritical drying(SCD)and conventional drying,respectively.Then,a series of nickel-based catalyst samples supported on these supports were prepared by the incipient wetness impregnation method with an aqueous solution of nickel nitrate as well as lanthanum nitrate as impregnation liquids.Based on the characterization results of nitrogen adsorption-desorption (BET),X-ray diffraction(XRD),temperature programmed reduction(TPR),temperature-programmed desorption of hydrogen(H2-TPD),and catalytic activity evaluation,the physico-chemical properties and catalytic performances of the catalysts were investigated.The results show that the nickel crystallites on the binary nickel catalyst using silica aerogel as support are of smaller particle size.However,compared with the sample supported on silica xerogel,the nickel catalyst supported on the silica aerogel exhibits lower activity and selectivity for the hydrogenation of m-dinitrobenzene because it has a lesser amount of active sites and weaker absorption ability to reactants caused by sintering of the nickel crystallites.The addition of promoter La2O3 could increase the activity and selectivity of the catalysts.Among all the nickel-based catalyst samples prepared,the La2O3 promoted ternary nickel-based catalyst supported on silica xerogel exhibits the highest activity and selectivity for the hydrogenation of m-dinitrobenzene to m-phenylenediamine,which could be attributed to its highest active surfacc area and appropriate absorption strength to reactants.Over this promising catalyst,me conversion of m-dinitrobenzene and the yield of m-phenylenediamine could reach 97.0%and 93.1%,respectively,under proper reaction conditions of hydrogen pressure 2.6 MPa

  14. Highly efficient, quick and green synthesis of biarlys with chitosan supported catalyst using microwave irradiation in the absence of solvent.

    Science.gov (United States)

    Baran, Talat; Açıksöz, Eda; Menteş, Ayfer

    2016-05-20

    The aim of this study was to develop a quick reaction that had high activity with a small amount of catalyst, which could be an eco-friendly alternative technique for the synthesis of biarlys in Suzuki coupling reactions. First, a novel chitosan Schiff base supported Pd(II) catalyst was synthesized, and its structure was illuminated with FTIR, (1)H NMR, (13)C NMR, TG/DTG, SEM/EDAX, XRD, ICP-OES, UV-vis, magnetic moment, and molar conductivity techniques. Subsequently, the catalytic activity of the catalyst was tested in Suzuki C-C reactions under microwave irradiation using a solvent-free reaction condition. The catalytic tests showed an excellent activity with a small load of the catalyst (0.02 mol%) in 4 min. The catalyst showed seven runs without loss of activity, and high values of turnover numbers (TON) and turnover frequency (TOF) were obtained. The novel biopolymer supported Pd(II) catalyst provided much faster reaction times, higher yields, and reusability under microwave heating compared to classic heating methods.

  15. Preparation of IrO2 nanoparticles with SBA-15 template and its supported Pt nanocomposite as bifunctional oxygen catalyst

    Science.gov (United States)

    Kong, Fan-Dong; Liu, Jing; Ling, Ai-Xia; Xu, Zhi-Qiang; Wang, Hui-Yun; Kong, Qing-Sheng

    2015-12-01

    In the present work, we report the syntheses of IrO2 nanoparticles with SBA-15 template (s-IrO2), and s-IrO2 supported Pt nanocomposite (Pt/s-IrO2) as bifunctional oxygen catalyst. Physical characterizations including X-ray diffraction and transmission electron microscopy demonstrate that s-IrO2 catalyst has excellent uniformity and regularity in particle shape and much ordered distribution in geometric space, and Pt/s-IrO2 catalyst shows a uniform Pt dispersion on the surface of the s-IrO2 particles. Electrochemical analyses prove that s-IrO2 catalyst possesses superior OER activity at operating potentials; and that Pt/s-IrO2 catalyst, in comparison to Pt/commercial IrO2, has higher ESA value and ORR catalytic performance with a mechanism of four-electron pathway and a high ORR efficiency. And as a bifunctional oxygen catalyst, Pt/s-IrO2 also exhibits more remarkable OER performance than the commercial one. The s-IrO2 nanoparticles will be a promising active component (for OER), and suitable for Pt support (for ORR).

  16. 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.

  17. Ultrafine porous carbon fiber and its supported platinum catalyst for enhancing performance of proton exchange membrane fuel cells

    International Nuclear Information System (INIS)

    The enhancement of electrocatalytic activity of carbon-supported platinum catalysts has been essential for improving the performance of proton exchange membrane fuel cells (PEMFCs). In this paper, one kind of grounded ultrafine porous carbon fiber (UPCF), with an average diameter of the order of 100 nm and pore sizes of 5–30 nm, was used as a novel compound carbon support (CCS) to prepare a supported Pt catalyst (Pt/CCS) for the electrode catalyst layer in a PEMFC, and its associated membrane electrode assembly (MEA). The fabricated MEA was also tested in a single fuel cell to validate this Pt/CCS catalyst. The electrochemical surface area (ECSA) of Pt was determined to be 71.9 m2.g−1 for the CCS, which is much larger than the 54.6 m2.g−1 known to apply for carbon black support. Both the onset potential and half-wave potential of Pt/CCS were all positively shifted in comparison with Pt/C, based on linear sweep voltammetry (LSV). The performance of a single fuel cell catalyzed by Pt/CCS showed 1.25 times higher power density than that catalyzed by Pt/C at room temperature. The cross-sectional morphology of the electrode indicated the chopped-fiber-form UPCF might construct a loose three-dimensionally layer-like catalyst that could reduce mass transform resistance and allow the water produced to escape easily

  18. Effects of CO2 content on the activity and stability of nickel catalyst supported on mesoporous nanocrystalline zirconia

    Institute of Scientific and Technical Information of China (English)

    M.Rezaei; S.M.Alavi; S.Sahebdelfar; Zi-Feng Yan

    2008-01-01

    The effects of carbon dioxide content on the catalytic performance and coke formation of nickel catalyst supported on mesoporous nanocrystalline zirconia with high surface area and pure tetragonaI crystalline phase were investigated in methane reforming with carbon dioxide.The samples were characterized bV XRD,BET,PR,TPO,TPH,TEM,and SEM techniques.The catalyst prepared showed high surface area and a mesoporous structure with a narrow pore size distribution.The obtained results revealed that the increase in CO2 content increased the methane conversion and stability of the catalyst and significantly reduced the coke deposition.The TPH analysis showed that several species of carbon with different reactivities toward hydrogenation were deposited on the spent catalysts employed under different CO2 contents.

  19. Palladium catalysts supported on novel CexY1-xO washcoats for toluene catalytic combustion

    Institute of Scientific and Technical Information of China (English)

    JIN Lingyun; HE Mai; LU Jiqing; LUO Mengfei; GAO Libiao; HE Jun

    2008-01-01

    Novel CexY1-xO washcoats adhered on the cordierite honeycomb, used as supports for Pd catalysts, were prepared by an impregnation method. It was found that the CexY1-xO washcoats had better adhesion and higher adsorption efficiency of H2PdCl4, and the optimal component of the washcoat was Ce0.8Y0.2O. Model reaction of catalytic combustion of toluene was chosen to evaluate the performance of the developed Pd/CexY1-xO/substrate catalysts. The results showed that the catalytic performance of the Pd/CexY1-xO/substrate catalysts depended on the component of the washcoats, with the Pd/Ce0.8Y0.2O/ substrate catalyst giving the best catalytic activity and thermal stability.

  20. 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.

    2015-06-01

    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.

  1. 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.

  2. Rice Husk Supported Catalysts for Degradation of Chlorobenzenes in Capillary Microreactor

    Directory of Open Access Journals (Sweden)

    Abdulelah Thabet

    2015-01-01

    Full Text Available Chlorinated organic pollutants are persistent, toxic, and ubiquitously distributed environmental contaminants. These compounds are highly bioaccumulative and adversely affect the ozone layer in the atmosphere. As such, their widespread usage is a major cause of environmental and health concern. Therefore, it is important to detoxify such compounds by environment friendly methods. In this work, rice husk supported platinum (RHA-Pt and titanium (RHA-Ti catalysts were used, for the first time, to investigate the detoxification of chlorobenzenes in a glass capillary microreactor. High potential (in kV range was applied to a reaction mixture containing buffer solution in the presence of catalyst. Due to high potential, hydroxyl and hydrogen radicals were produced, and the reaction was monitored by gas chromatography-mass spectrometry. The main advantage of this capillary reactor is the in situ generation of hydrogen for the detoxification of chlorobenzene. Various experimental conditions influencing detoxification were optimized. Reaction performance of capillary microreactor was compared with conventional catalysis. Only 20 min is sufficient to completely detoxify chlorobenzene in capillary microreactor compared to 24 h reaction time in conventional catalytic method. The capillary microreactor is simple, easy to use, and suitable for the detoxification of a wide range of chlorinated organic pollutants.

  3. 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.

  4. 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.

  5. Outstanding low temperature HC-SCR of NOx over platinum-group catalysts supported on mesoporous materials expecting diesel-auto emission regulation

    International Nuclear Information System (INIS)

    Outstanding low temperature HC-SCR of NOx over platinum-group catalysts supported on mesoporous materials, which does not rely on the conventional NOx-absorption-reduction-catalysts, is presented for the purpose of de-NOx of diesel-auto emissions. The established catalysts basically consist of mesoporous silica or metal-substituted mesoporous silicates for supports and platinum for active species, which is operated under lean- and rich-conditions. The new catalysts are very active at 150-200oC and free from difficult problems of SOx-deactivation and hydrothermal ageing of the NOx-absorption-reduction catalyst. (author)

  6. Comparative study on stability and coke deposition over supported Rh and FePO4 catalysts for oxy-bromination of methane

    Institute of Scientific and Technical Information of China (English)

    Ronghe; Lin; Yunjie; Ding; Runqin; Wang

    2014-01-01

    Rhodium- and iron phosphate-based catalysts are by far the most promising catalysts for oxy-bromination of methane(OBM) reaction. However, most literature reported either Rh- or FePO4-based catalysts, and the results were rarely studied in a uniform environmental condition. In this report, comparative study was conducted on silica- and silicon carbide-supported rhodium and iron phosphate catalysts with the main focuses on stability performance and coke deposition. The catalytic results demonstrated that the stability of both Rh- and FePO4-based catalysts was greatly influenced by the supports used, and silicon carbide-supported catalysts showed much better anti-coking ability as compared with silica-supported ones. Temperature-programmed oxidation over the used catalysts further indicated that the coke formation mechanisms were completely different between silica-supported rhodium and iron phosphate catalysts. While cokes might be caused by condensation of CH2Br2over supported iron phosphate, methane decomposition might be the reason for coke formation over silica-supported rhodium catalyst. These findings might pave the way for designing highly efficient and stable catalysts of the OBM reaction.

  7. Gas Phase Polymerization of Ethylene with Supported Titanium-Nickel Catalysts

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A new ditransition-metal catalyst system TiCl4-NiCl2/MgCl2-SiO2/AlR3 was prepared.Gas phase polymerization of ethylene with the catalysts has been studied.The kinetic curves of gas phase polymerization showed a decline.The catalystic efficiency and polymerization reaction rates have a optimum value when Ni content of the catalysts was 12.5%(mol).The products obtained are branched polyethylene.

  8. A palladium-doped ceria@carbon core-sheath nanowire network: a promising catalyst support for alcohol electrooxidation reactions

    Science.gov (United States)

    Tan, Qiang; Du, Chunyu; Sun, Yongrong; Du, Lei; Yin, Geping; Gao, Yunzhi

    2015-08-01

    A novel palladium-doped ceria and carbon core-sheath nanowire network (Pd-CeO2@C CSNWN) is synthesized by a template-free and surfactant-free solvothermal process, followed by high temperature carbonization. This hierarchical network serves as a new class of catalyst support to enhance the activity and durability of noble metal catalysts for alcohol oxidation reactions. Its supported Pd nanoparticles, Pd/(Pd-CeO2@C CSNWN), exhibit >9 fold increase in activity toward the ethanol oxidation over the state-of-the-art Pd/C catalyst, which is the highest among the reported Pd systems. Moreover, stability tests show a virtually unchanged activity after 1000 cycles. The high activity is mainly attributed to the superior oxygen-species releasing capability of Pd-doped CeO2 nanowires by accelerating the removal of the poisoning intermediate. The unique interconnected one-dimensional core-sheath structure is revealed to facilitate immobilization of the metal catalysts, leading to the improved durability. This core-sheath nanowire network opens up a new strategy for catalyst performance optimization for next-generation fuel cells.A novel palladium-doped ceria and carbon core-sheath nanowire network (Pd-CeO2@C CSNWN) is synthesized by a template-free and surfactant-free solvothermal process, followed by high temperature carbonization. This hierarchical network serves as a new class of catalyst support to enhance the activity and durability of noble metal catalysts for alcohol oxidation reactions. Its supported Pd nanoparticles, Pd/(Pd-CeO2@C CSNWN), exhibit >9 fold increase in activity toward the ethanol oxidation over the state-of-the-art Pd/C catalyst, which is the highest among the reported Pd systems. Moreover, stability tests show a virtually unchanged activity after 1000 cycles. The high activity is mainly attributed to the superior oxygen-species releasing capability of Pd-doped CeO2 nanowires by accelerating the removal of the poisoning intermediate. The unique

  9. Isolated catalyst sites on amorphous supports: A systematic algorithm for understanding heterogeneities in structure and reactivity

    Science.gov (United States)

    Goldsmith, Bryan R.; Sanderson, Evan D.; Bean, Daniel; Peters, Baron

    2013-05-01

    Methods for modeling catalytic sites on amorphous supports lag far behind methods for modeling catalytic sites on metal surfaces, zeolites, and other crystalline materials. One typical strategy for amorphous supports uses cluster models with arbitrarily chosen constraints to model the rigid amorphous support, but these constraints arbitrarily influence catalyst site activity. An alternative strategy is to use no constraints, but this results in catalytic sites with unrealistic flexibility. We present a systematic ab initio method to model isolated active sites on insulating amorphous supports using small cluster models. A sequential quadratic programming framework helps us relate chemical properties, such as the activation energy, to active site structure. The algorithm is first illustrated on an empirical valence bond model energy landscape. We then use the algorithm to model an off-pathway kinetic trap in olefin metathesis by isolated Mo sites on amorphous SiO2. The cluster models were terminated with basis set deficient fluorine atoms to mimic the properties of an extended silica framework. We also discuss limitations of the current algorithm formulation and future directions for improvement.

  10. Gas phase polymerization of ethylene with a silica-supported metallocene catalyst: influence of temperature on deactivation

    OpenAIRE

    Roos, Peter; Meier, Gerben B.; Samson, Job Jan C.; Weickert, Günter; Westerterp, K. Roel

    1997-01-01

    Ethylene was polymerized at 5 bar in a stirred powder bed reactor with silica supported rac-Me2Si[Ind]2ZrCl2/methylaluminoxane (MAO) at temperatures between 40°C and 80°C using NaCl as support bed and triethylaluminium (TEA) as a scavenger for impurities. For this fixed recipe and a given charge of catalyst. the average catalyst activity is reproducible within 10% for low temperatures. The polymerization rate and the rate of deactivation increase with increasing temperature. The deactivation ...

  11. Preparation and characterization of titanium dioxide nanotube array supported hydrated ruthenium oxide catalysts

    Science.gov (United States)

    Giang, Thi Phuong Ly; Tran, Thi Nhu Mai; Le, Xuan Tuan

    2012-03-01

    This work aimed at preparing and characterizing TiO2 nanotube supported hydrated ruthenium oxide catalysts. First of all, we succeeded in preparing TiO2 nanotube arrays by electrochemical anodization of titanium metal at 20 V for 8 h in a 1M H3PO4+0.5 wt% HF solution as evidenced from scanning electron microscopy (SEM) and x-ray photoelectron spectroscopy (XPS) results. The hydrated ruthenium oxide was then deposited onto TiO2 nanotubes by consecutive exchange of protons by Ru3+ ions, followed by formation of hydrated oxide during the alkali treatment. Further XPS measurements showed that the modified samples contain not only hydrated ruthenium oxide but also hydrated ruthenium species Ru(III)-OH.

  12. Chitosan-coated Silica Nanoparticles - A Potential Support for Metal Particles used as Heterogeneous Catalyst

    International Nuclear Information System (INIS)

    In this work a strategy to immobilize noble metal nanoparticles on silica microspheres is proposed. In order to achieve this, monodispersed silica nanoparticles of an average size of 63.5±6.7 nm were synthesized via sol-gel method. Then chitosan was coated onto the silica to create a core/ shell composite with the size range of 66.56±9.78 nm to 79.18±11.87 nm. The noble metal nanoparticles were then synthesized on the shell of the composite through coordination of the respective metal ions to the polymer followed by the subsequent reduction. In this way, the silver particles of average size 6.17±1.83 nm, 9.85±2.60 nm, and 11.80±4.26 nm have been synthesized on the shell successfully. The optimized supported metal particles can be used as a potential heterogeneous catalyst. (author)

  13. Cellulose conversion to polyols on supported Ru catalysts in aqueous basic solution

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    It is of great significance and challenge to achieve direct conversion of cellulose to specific polyols,e.g.,ethylene glycol and propylene glycol.For such selective conversion,a novel one-pot approach was studied by combination of alkaline hydrolysis and hydrogenation on supported Ru catalysts.A wide range of bases including solid bases,e.g.,Ca(OH)2 and La2O3,and phosphate buffers were examined in the cellulose reaction in water,and the cellulose conversions and polyol products depended largely on the basicity or pH values in the aqueous solutions.Ethylene glycol,1,2-propanediol,and especially 1,2,5-pentanetriol were obtained with selectivities of 15%,14% and 22%,respectively,at 38% cellulose conversion at pH 8 in phosphate buffer solution.These preliminary results provide potentials for efficient conversion of cellulose to targeted polyols by using the advantages of bases.

  14. Electro-synthesis of novel nanostructured PEDOT films and their application as catalyst support

    Directory of Open Access Journals (Sweden)

    Yan Yushan

    2011-01-01

    Full Text Available Abstract Poly(3,4-ethylenedioxythiophene (PEDOT films doped with nitric and chlorine ions have been electrochemically deposited simply by a one-step electrochemical method in an aqueous media in the absence of any surfactant. The fabricated PEDOT films were characterized by scanning electron microscopy, transmission electron microscopy, and Raman spectroscopy. The results indicate that the hierarchical structured PEDOT film doped with nitric ions displays a 'lunar craters' porous morphology consisting of PEDOT nano-sheets with a thickness of less than 2 nm. The effect of counter ions on the electro-polymerization, the electrochemistry, and the morphology of the polymer film was studied. Compared with PEDOT film doped with nitric acid, PEDOT film deposited in the presence of chlorine ions shows irregular morphology and less electrochemical activity. The specific nanostructure of the polymer was further studied as catalyst support for platinum nanoparticles to methanol electro-oxidation.

  15. Fabrication of Novel Titanium-supported Ni-Sn Catalysts for Methanol Electro-oxidation

    Institute of Scientific and Technical Information of China (English)

    YI Qing-Feng; HUANG Wu; YU Wen-Qiang; LI Lei; LIU Xiao-Ping

    2008-01-01

    Novel titanium-supported Ni-Sn/Ti electrodes (Ni8Sn/Ti, Ni7Sn3/Ti and Ni/Ti) have been prepared using a hydrothermal method by a one step process. The scanning electron microscopy (SEM) images show that the catalyst particles are present as nano-scale flakes. Their electrochemical activity for methanol oxidation in 1 mol·L-1 NaOH was evaluated using voltammetric techniques, chronoamperometric measurements and electrochemical impedance spectra (EIS). It was found that the Ni8Sn/Ti electrode presents higher anodic currents and lower onset potential for methanol oxidation than Ni7Sn3/Ti, Ni/Ti and polycrystalline Ni electrodes. The EIS data indicate that under condi- tions of various anodic potentials and methanol concentrations, the Ni8Sn/Ti electrode displays significantly lower charge transfer resistances and high electrocatalytic activity towards methanol oxidation.

  16. Dinucleating Ligand Platforms Supporting Indium and Zinc Catalysts for Cyclic Ester Polymerization.

    Science.gov (United States)

    Kremer, Alexandre B; Osten, Kimberly M; Yu, Insun; Ebrahimi, Tannaz; Aluthge, Dinesh C; Mehrkhodavandi, Parisa

    2016-06-01

    The synthesis of the first alkoxide-bridged indium complex supported by a chiral dinucleating ligand platform (1), along with its zinc analogue (2), is reported. Both complexes are synthesized in a one-pot reaction starting from a chiral dinucleating bis(diamino)phenolate ligand platform, sodium ethoxide, and respective metal salts. The dinucleating indium analogue (7) based on an achiral ligand backbone is also reported. Indium complexes bearing either the chiral or achiral ligand catalyze the ring-opening polymerization of racemic lactide (rac-LA) to afford highly heterotactic poly(lactic acid) (PLA; Pr > 0.85). The indium complex bearing an achiral ligand affords essentially atactic PLA from meso-LA. The role of the dinucleating ligand structure in catalyst synthesis and polymerization activity is discussed. PMID:27187767

  17. Alumina supported/unsupported mixed oxides of Ca and Mg as heterogeneous catalysts for transesterification of Nannochloropsis sp. microalga’s oil

    International Nuclear Information System (INIS)

    Highlights: • Biodiesel made from oleaginous microalgae through transesterification process. • Effects of methanol/oil molar ratio, catalyst amount, reaction temperature and reaction time were optimized. • High biodiesel yields (75% and 85%) achieved at 60 °C. • The supported catalyst was very sustainable in high water content feedstocks. • The catalysts were characterized using TGA, XRD, FTIR, TPD-CO2 and SEM. - Abstract: In this study, calcium magnesium (CaMgO) and alumina (Al2O3) supported CaMgO mixed oxide catalysts were prepared via pH-controlled co-precipitation (Na2CO3 and NaOH as a precipitant) for transesterification of crude Nannochloropsis oculata (N. oculata) oil with methanol. The catalysts were characterized by means of Thermogravimetric analyses (TGA), X-ray diffraction (XRD), Fourier transform-infrared (FTIR), Temperature programmed desorption of CO2 (CO2-TPD), Inductively coupled plasma–atomic emission spectrometer (ICP–AES) and Scanning electron microscopy (SEM) analysis. At optimization condition, CaMgO mixed oxide catalyst showed 75.2% of fatty acid methyl ester (FAME) yield with catalyst loading of 20 wt.% at 3 h. Meanwhile, the supported CaMgO mixed oxide catalyst gave a higher FAME yield of 85.3% with catalyst loading of 10 wt.% at same conditions. Besides, the reusability study of catalyst was performed to investigate the stability and durability of supported/unsupported catalysts. The high content of Ca2+ and Mg2+ precipitated on Al2O3 supported CaMgO mixed oxide catalyst tend to increase the total basicity and provide more active sites for transesterification reaction. Moreover, better moisture resistant on the Al2O3 supported CaMgO mixed oxide catalyst compared with CaMgO mixed oxide catalyst, which is favourable for transesterification reaction on high water content microalgae oil

  18. TiN@nitrogen-doped carbon supported Pt nanoparticles as high-performance anode catalyst for methanol electrooxidation

    Science.gov (United States)

    Zhang, Jun; Ma, Li; Gan, Mengyu; Fu, Shenna; Zhao, Yi

    2016-08-01

    In this paper, TiN@nitrogen-doped carbons (NDC) composed of a core-shell structure are successfully prepared through self-assembly and pyrolysis treatment using γ-aminopropyltriethoxysilane as coupling agent, polyaniline as carbon and nitrogen source, respectively. Subsequently, TiN@NDC supporting Pt nanoparticles (Pt/TiN@NDC) are obtained by a microwave-assisted polyol process. The nitrogen-containing functional groups and TiN nanoparticles play a critical role in decreasing the average particle size of Pt and improving the electrocatalytic activity of Pt/TiN@NDC. Transmission electron microscope results reveal that Pt nanoparticles are uniformly dispersed in the TiN@NDC surface with a narrow particle size ranging from 1 to 3 nm in diameter. Moreover, the Pt/TiN@NDC catalyst shows significantly improved catalytic activity and high durability for methanol electrooxidation in comparison with Pt/NDC and commercial Pt/C catalysts, revealed by cyclic voltammetry and chronoamperometry. Strikingly, this novel Pt/TiN@NDC catalyst reveals a better CO tolerance related to Pt/NDC and commercial Pt/C catalysts, which due to the bifunctional mechanism and strong metal-support interaction between Pt and TiN@NDC. In addition, the probable reaction steps for the electrooxidation of CO adspecies on Pt NPs on the basis of the bifunctional mechanism are also proposed. These results indicate that the TiN@NDC is a promising catalyst support for methanol electrooxidation.

  19. Reverse Micelle Synthesis and Characterization of Supported Pt/Ni Bimetallic Catalysts on gamma-Al2O3

    Energy Technology Data Exchange (ETDEWEB)

    B Cheney; J Lauterbach; J Chen

    2011-12-31

    Reverse micelle synthesis was used to improve the nanoparticle size uniformity of bimetallic Pt/Ni nanoparticles supported on {gamma}-Al{sub 2}O{sub 3}. Two impregnation methods were investigated to optimize the use of the micelle method: (1) step-impregnation, where Ni nanoparticles were chemically reduced in microemulsion and then supported, followed by Pt deposition using incipient wetness impregnation, and (2) co-impregnation, where Ni and Pt were chemically reduced simultaneously in microemulsion and then supported. Transmission electron microscopy (TEM) was used to characterize the particle size distribution. Atomic absorption spectroscopy (AAS) was used to perform elemental analysis of bimetallic catalysts. Extended X-ray absorption fine structure (EXAFS) measurements were utilized to confirm the formation of the Pt-Ni bimetallic bond in the step-impregnated catalyst. CO pulse chemisorption and Fourier transform infrared spectroscopy (FTIR) studies of 1,3-butadiene hydrogenation in a batch reactor were performed to determine the catalytic activity. Step-impregnated Pt/Ni catalyst demonstrated enhanced hydrogenation activity over the parent monometallic Pt and Ni catalysts due to bimetallic bond formation. The catalyst synthesized using co-impregnation showed no enhanced activity, behaving similarly to monometallic Ni. Overall, our results indicate that reverse micelle synthesis combined with incipient wetness impregnation produced small, uniform nanoparticles with bimetallic bonds that enhanced hydrogenation activity.

  20. 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.)

  1. Synthesis of boron and nitrogen doped graphene supporting PtRu nanoparticles as catalysts for methanol electrooxidation

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Jiming; Zhou, Yingke, E-mail: zhouyk888@hotmail.com; Tian, Xiaohui; Xu, Xiao; Zhu, Hongxi; Zhang, Shaowei; Yuan, Tao

    2014-10-30

    Highlights: • A single-step heat treatment approach is developed to synthesize boron and nitrogen doped graphene supporting PtRu nanocatalysts. • The introduction of boron or nitrogen containing function groups into graphene can modulate the particle size and dispersion of the supporting PtRu nanoparticles. • The optimized catalysts present high electrocatalytic activity and excellent stability for methanol oxidation reaction. - Abstract: In this study, we demonstrate a single-step heat treatment approach to synthesize boron and nitrogen doped graphene supporting PtRu electrocatalysts for methanol electro-oxidation reaction. The reduction of graphene oxide, boron or nitrogen doping of graphene and loading of PtRu nanoparticles happened simultaneously during the reaction process. The morphologies and microstructures of the as-prepared catalysts were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The electrocatalytic methanol oxidation activity and durability of the obtained catalysts were evaluated by the cyclic voltammetry and chronoamperometric techniques. The results reveal that the boron and nitrogen doped graphene supporting PtRu electrocatalysts can be successfully prepared by the single step heat treatment technique, and the introduction of boron or nitrogen containing function groups into the reduced graphene sheets could modulate the particle size and dispersion of the supporting PtRu nanoparticles and improve the electrocatalytic performance of methanol oxidation reaction. The optimal annealing temperature is 800 °C, the preferable heat treatment time is 60 min for the nitrogen-doped catalysts and 90 min for the boron-doped catalysts, and the catalysts prepared under such conditions present superior catalytic activities for methanol oxidation than those prepared under other heat treatment conditions.

  2. Synthesis of boron and nitrogen doped graphene supporting PtRu nanoparticles as catalysts for methanol electrooxidation

    International Nuclear Information System (INIS)

    Highlights: • A single-step heat treatment approach is developed to synthesize boron and nitrogen doped graphene supporting PtRu nanocatalysts. • The introduction of boron or nitrogen containing function groups into graphene can modulate the particle size and dispersion of the supporting PtRu nanoparticles. • The optimized catalysts present high electrocatalytic activity and excellent stability for methanol oxidation reaction. - Abstract: In this study, we demonstrate a single-step heat treatment approach to synthesize boron and nitrogen doped graphene supporting PtRu electrocatalysts for methanol electro-oxidation reaction. The reduction of graphene oxide, boron or nitrogen doping of graphene and loading of PtRu nanoparticles happened simultaneously during the reaction process. The morphologies and microstructures of the as-prepared catalysts were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The electrocatalytic methanol oxidation activity and durability of the obtained catalysts were evaluated by the cyclic voltammetry and chronoamperometric techniques. The results reveal that the boron and nitrogen doped graphene supporting PtRu electrocatalysts can be successfully prepared by the single step heat treatment technique, and the introduction of boron or nitrogen containing function groups into the reduced graphene sheets could modulate the particle size and dispersion of the supporting PtRu nanoparticles and improve the electrocatalytic performance of methanol oxidation reaction. The optimal annealing temperature is 800 °C, the preferable heat treatment time is 60 min for the nitrogen-doped catalysts and 90 min for the boron-doped catalysts, and the catalysts prepared under such conditions present superior catalytic activities for methanol oxidation than those prepared under other heat treatment conditions

  3. Impact of carbon on the surface and activity of silica-carbon supported copper catalysts for reduction of nitrogen oxides

    Science.gov (United States)

    Spassova, I.; Stoeva, N.; Nickolov, R.; Atanasova, G.; Khristova, M.

    2016-04-01

    Composite catalysts, prepared by one or more active components supported on a support are of interest because of the possible interaction between the catalytic components and the support materials. The supports of combined hydrophilic-hydrophobic type may influence how these materials maintain an active phase and as a result a possible cooperation between active components and the support material could occur and affects the catalytic behavior. Silica-carbon nanocomposites were prepared by sol-gel, using different in specific surface areas and porous texture carbon materials. Catalysts were obtained after copper deposition on these composites. The nanocomposites and the catalysts were characterized by nitrogen adsorption, TG, XRD, TEM- HRTEM, H2-TPR, and XPS. The nature of the carbon predetermines the composite's texture. The IEPs of carbon materials and silica is a force of composites formation and determines the respective distribution of the silica and carbon components on the surface of the composites. Copper deposition over the investigated silica-carbon composites leads to formation of active phases in which copper is in different oxidation states. The reduction of NO with CO proceeds by different paths on different catalysts due to the textural differences of the composites, maintaining different surface composition and oxidation states of copper.

  4. Studies on accelerated deactivation of ruthenium-promoted alumina-supported alkalized cobalt Fischer-Tropsch synthesis catalyst

    Institute of Scientific and Technical Information of China (English)

    Shohreh Tehrani; Mohamad Irani; Ahmad Tavasoli; Yadollah Mortazavi; Abbas A.Khodadadi; Ali Nakhaei Pour

    2011-01-01

    Accelerated deactivation of ruthenium-promoted alumina-supported alkalized cobalt(K-Ru-Co/-γ-Al2O3)Fischer-Tropsch(FT)synthesis catalyst along the catalytic bed over 120 h of time-on-stream(TOS)was investigated.Catalytic bed was divided into three parts and structural changes of the spent catalysts collected from each catalytic bed after FT synthesis were studied using different techniques.Rapid deactivation was observed during the reaction due to high reaction temperature and low feed flow rates.The physico-chemical properties of the catalyst charged in the Bed #1 of the reactor did not change significantly.Interaction of cobalt with alumina and the formation of CoAl2O4 increased along the catalytic bed.Reducibility percentage decreased by 4.5%,7.5% and 12.9% for the catalysts in the Beds #1,#2 and #3,respectively.Dispersion decreased by 8.8%,14.4% and 26.6% for the catalysts in the Beds #1,#2 and #3,respectively.Particle diameter increased by 0.6%,2.4% and 10.4% for the catalysts in the Beds #1,#2 and #3,respectively,suggesting higher rate of sintering at the last catalytic bed.The amount of coke at the last catalytic bed was significantly higher than those of Beds #1 and #2.

  5. Cationic Silica-Supported N-Heterocyclic Carbene Tungsten Oxo Alkylidene Sites: Highly Active and Stable Catalysts for Olefin Metathesis.

    Science.gov (United States)

    Pucino, Margherita; Mougel, Victor; Schowner, Roman; Fedorov, Alexey; Buchmeiser, Michael R; Copéret, Christophe

    2016-03-18

    Designing supported alkene metathesis catalysts with high activity and stability is still a challenge, despite significant advances in the last years. Described herein is the combination of strong σ-donating N-heterocyclic carbene ligands with weak σ-donating surface silanolates and cationic tungsten sites leading to highly active and stable alkene metathesis catalysts. These well-defined silica-supported catalysts, [(≡SiO)W(=O)(=CHCMe2 Ph)(IMes)(OTf)] and [(≡SiO)W(=O)(=CHCMe2 Ph)(IMes)(+) ][B(Ar(F) )4 (-) ] [IMes=1,3-bis(2,4,6-trimethylphenyl)-imidazol-2-ylidene, B(Ar(F) )4 =B(3,5-(CF3 )2 C6 H3 )4 ] catalyze alkene metathesis, and the cationic species display unprecedented activity for a broad range of substrates, especially for terminal olefins with turnover numbers above 1.2 million for propene. PMID:26928967

  6. STUDIES ON THE STATE OF PALLADIUM AND HYDROGENATION ACTIVITY OF RESIN SUPPORTED PALLADIUM—TIN OXIDE CATALYSTS

    Institute of Scientific and Technical Information of China (English)

    HuWeibing; ZhangShengming; 等

    1994-01-01

    Sereral Pd-SnO2/D3520 and Pd-PbO/D3520 catalysts with Pd/D3520,SnO2/D3520 and PbO/D3520 catalysts as reference were studied by means of IR and XPS.Interaction between Pd and the second metal or between metal and support was observed.Results show that there is a strong interaction between Pd and the second metal,but there is not an obvious interaction between metal and support.The active constituent is Pd.Hydrogenation activity of the catalysts is altered because of the interaction between Pd and the second metal.The activity of the catalysis for hydrogenation has relation to outer layer valence electron density of Pd.

  7. Cationic Silica-Supported N-Heterocyclic Carbene Tungsten Oxo Alkylidene Sites: Highly Active and Stable Catalysts for Olefin Metathesis.

    Science.gov (United States)

    Pucino, Margherita; Mougel, Victor; Schowner, Roman; Fedorov, Alexey; Buchmeiser, Michael R; Copéret, Christophe

    2016-03-18

    Designing supported alkene metathesis catalysts with high activity and stability is still a challenge, despite significant advances in the last years. Described herein is the combination of strong σ-donating N-heterocyclic carbene ligands with weak σ-donating surface silanolates and cationic tungsten sites leading to highly active and stable alkene metathesis catalysts. These well-defined silica-supported catalysts, [(≡SiO)W(=O)(=CHCMe2 Ph)(IMes)(OTf)] and [(≡SiO)W(=O)(=CHCMe2 Ph)(IMes)(+) ][B(Ar(F) )4 (-) ] [IMes=1,3-bis(2,4,6-trimethylphenyl)-imidazol-2-ylidene, B(Ar(F) )4 =B(3,5-(CF3 )2 C6 H3 )4 ] catalyze alkene metathesis, and the cationic species display unprecedented activity for a broad range of substrates, especially for terminal olefins with turnover numbers above 1.2 million for propene.

  8. Durability of Carbon Nanofiber (CNF) & Carbon Nanotube (CNT) as Catalyst Support for Proton Exchange Membrane Fuel Cells

    DEFF Research Database (Denmark)

    Andersen, Shuang Ma; Borghei, Maryam; Lund, Peter;

    2013-01-01

    (normally carbon black) is one of the essential degradation mechanisms during cell operation. In this work, durability of Carbon Nanofibers (CNF) & Carbon Nanotubes (CNT) as alternative platinum catalyst supports for Proton Exchange Membrane Fuel Cells (PEMFCs) was assessed. Platinized CNF and CNT using...... a standard polyol method were prepared and fabricated as cathodes of Membrane Electrode Assemblies (MEA) for PEMFC. Both the catalysts as such and the MEAs made out of them were evaluated regarding to thermal and electrochemical stability using traditional carbon black (Vulcan XC72) as a reference. Thermal...... gravimetric analysis (TGA), cyclic voltammetry (CV), polarization curve and impedance spectroscopy were applied on the samples under accelerated stress conditions. The carbon nano-materials demonstrated better stability as support for nano-sized platinum catalyst under PEMFC related operating conditions. Due...

  9. Carbon nanotubes-Nafion composites as Pt-Ru catalyst support for methanol electro-oxidation in acid media

    Institute of Scientific and Technical Information of China (English)

    Shengzhou Chen; Fei Ye; Weiming Lin

    2009-01-01

    Carbon nanotubes-Nafion (CNTs-Nafion) composites were prepared by impregnated CNTs with Nafion in ethanol solution and characterized by FT-IR. Pt-Ru catalysts supported on CNTs-Nafion composites were synthesized by microwave-assisted polyol process. The physical and electrochemical properties of the catalysts were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), CO stripping voltammetry, cyclic voltammetry (CV) and chronoamperometry (CA). The results showed that the Nafion incorporation in CNTs-Nafion composites did not significantly alter the oxygen-containing groups on the CNTs surface. The Pt-Ru catalyst supported on CNTs-Nafion composites with 2 wt% Nafion showed good dispersion and the best CO oxidation and methanol electro-oxidation activities.

  10. Dynamical Observation and Detailed Description of Catalysts under Strong Metal-Support Interaction.

    Science.gov (United States)

    Zhang, Shuyi; Plessow, Philipp N; Willis, Joshua J; Dai, Sheng; Xu, Mingjie; Graham, George W; Cargnello, Matteo; Abild-Pedersen, Frank; Pan, Xiaoqing

    2016-07-13

    Understanding the structures of catalysts under realistic conditions with atomic precision is crucial to design better materials for challenging transformations. Under reducing conditions, certain reducible supports migrate onto supported metallic particles and create strong metal-support states that drastically change the reactivity of the systems. The details of this process are still unclear and preclude its thorough exploitation. Here, we report an atomic description of a palladium/titania (Pd/TiO2) system by combining state-of-the-art in situ transmission electron microscopy and density functional theory (DFT) calculations with structurally defined materials, in which we visualize the formation of the overlayers at the atomic scale under atmospheric pressure and high temperature. We show that an amorphous reduced titania layer is formed at low temperatures, and that crystallization of the layer into either mono- or bilayer structures is dictated by the reaction environment and predicted by theory. Furthermore, it occurs in combination with a dramatic reshaping of the metallic surface facets. PMID:27280326

  11. Electro-oxidation of Ethanol on Carbon Supported PtSn and PtSnNi Catalysts

    Directory of Open Access Journals (Sweden)

    Nur Hidayati

    2016-03-01

    Full Text Available Even though platinum is known as an active electro-catalyst for ethanol oxidation at low temperatures (< 100 oC, choosing the electrode material for ethanol electro-oxidation is a crucial issue. It is due to its property which easily poisoned by a strong adsorbed species such as CO. PtSn-based electro-catalysts have been identified as better catalysts for ethanol electro-oxidation. The third material is supposed to improved binary catalysts performance. This work presents a study of the ethanol electro-oxidation on carbon supported Pt-Sn and Pt-Sn-Ni catalysts. These catalysts were prepared by alcohol reduction. Nano-particles with diameters between 2.5-5.0 nm were obtained. The peak of (220 crystalline face centred cubic (fcc Pt phase for PtSn and PtSnNi alloys was repositioned due to the presence of Sn and/or Ni in the alloy. Furthermore, the modification of Pt with Sn and SnNi improved ethanol and CO electro-oxidation. Copyright © 2016 BCREC GROUP. All rights reserved Received: 10th November 2015; Revised: 1st February 2016; Accepted: 1st February 2016 How to Cite: Hidayati, N., Scott, K. (2016. Electro-oxidation of Ethanol on Carbon Supported PtSn and PtSnNi Catalysts. Bulletin of Chemical Reaction Engineering & Catalysis, 11 (1: 10-20. (doi:10.9767/bcrec.11.1.394.10-20 Permalink/DOI: http://dx.doi.org/10.9767/bcrec.11.1.394.10-20

  12. Effect of Surface Oxygen Containing Groups on the Catalytic Activity of Multi-walled Carbon Nanotube Supported Pt Catalyst

    Energy Technology Data Exchange (ETDEWEB)

    X Wang; N Li; J Webb; L Pfefferle; G Haller

    2011-12-31

    Multi-walled carbon nanotubes (MWNT) supported platinum catalysts were employed to study the support functionalization on their catalytic performances. The MWNT were subjected to HNO{sub 3} functionalization, in which oxygen-containing-groups (OCGs) were introduced to improve Pt dispersion. The MWNT supports were characterized by nitrogen physisorption and NEXAFS, and the Pt supported on differently functionalized MWNT characterized by X-ray absorption, TEM and both hydrogen and CO chemisorption. Compared to the as received MWNT supports, Pt dispersion is improved on the HNO3 treated MWNT supports, but the turnover frequency (TOF) of aqueous phase reforming decreases by half. The TOF can be recovered by removing the OCGs via high temperature annealing. To further investigate the OCGs effect, different probe reactions, including both steam reforming and liquid phase reforming of hydrocarbon oxygenates and dehydrogenation of alkanes in the liquid and gas phases, have been performed on the MWNT supported catalysts with different OCGs. A comparison of these reaction results suggests that OCGs are only detrimental to reactions in a binary mixture with two components of different hydrophilicity due to their competitive adsorption on the catalyst supports.

  13. Selective catalytic oxidation of H2S over iron oxide supported on alumina-intercalated Laponite clay catalysts

    International Nuclear Information System (INIS)

    Graphical abstract: The catalytic reaction and deactivation mechanisms for H2S selective oxidation over Fe/Al-Lap catalysts are shown in the illustration. The catalytic reaction follows Mars–van Krevelen mechanism. Moreover, the interaction between iron oxide and alumina, the strong acidity of the catalysts and the well dispersion of iron oxide improve the catalytic performance efficiently. Meanwhile, the catalyst deactivation is mainly due to the formation of Fe2(SO4)3 and elemental sulfur deposits on the surface. -- Highlights: • Fe/Al-Lap catalysts with mesoporous structure were synthesized. • Iron oxide mainly exists in form of isolate Fe3+ in an oxidic environment. •Fe/Al-Lap catalysts show high catalytic activities at low temperature. •The high catalytic activities are ascribed to the interaction between iron oxide and alumina. •The formed Fe2(SO4)3 and elemental sulfur deposits on surface cause catalyst deactivation. -- Abstract: A series of iron oxide supported on alumina-intercalated clay catalysts (named Fe/Al-Lap catalysts) with mesoporous structure and high specific surface area were prepared. The structural and chemical properties were studied by nitrogen sorption isotherms, X-ray diffraction (XRD), UV–vis diffuse reflectance spectra (UV–vis DRS), X-ray photoelectron spectra (XPS), Fourier transform infrared spectroscopy (FTIR), H2 temperature-programmed reduction (H2-TPR) and NH3 temperature-programmed desorption (NH3-TPD) techniques. It was realized that iron oxide mainly existed in the form of isolated Fe3+ in an oxidic environment. Fe/Al-Lap catalysts showed high catalytic activities in the temperature range of 120–200 °C without the presence of excessive O2. This can be attributed to the interaction between iron oxide and alumina, which improve the redox property of Fe3+ efficiently. In addition, the strong acidity of catalysts and good dispersion of iron oxide were also beneficial to oxidation reaction. Among them, 7% Fe

  14. SISGR-Fundamental Experimental and Theoretical Studies on a Novel Family of Oxide Catalyst Supports for Water Electrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Kumta, Prashant [University of Pittsburgh

    2014-10-03

    Identification and development of non-noble metal based electro-catalysts or electro-catalysts with significant reduction of expensive noble metal contents (E.g. IrO2, Pt) with comparable electrochemical performance as the standard noble metal/metal oxide for proton exchange membrane (PEM) based water electrolysis would constitute a major breakthrough in the generation of hydrogen by water electrolysis. Accomplishing such a system would not only result reduction of the overall capital costs of PEM based water electrolyzers, but also help attain the targeted hydrogen production cost [< $ 3.0 / gallon gasoline equivalent (gge)] comparable to conventional liquid fuels. In line with these goals, it was demonstrated that fluorine doped IrO2 thin films and nanostructured high surface area powders display remarkably higher electrochemical activity, and comparable durability as pure IrO2 electro-catalyst for the oxygen evolution reaction (OER) in PEM based water electrolysis. Furthermore, corrosion resistant SnO2 and NbO2 support has been doped with F and coupled with IrO2 or RuO2 for use as an OER electro-catalyst. A solid solution of SnO2:F or NbO2:F with only 20 - 30 mol.% IrO2 or RuO2 yielding a rutile structure in the form of thin films and bulk nanoparticles displays similar electrochemical activity and stability as pure IrO2/RuO2. This would lead to more than 70 mol.% reduction in the noble metal oxide content. Novel nanostructured ternary (Ir,Sn,Nb)O2 thin films of different compositions FUNDAMENTAL STUDY OF NANOSTRUCTURED ELECTRO-CATALYSTS WITH REDUCED NOBLE METAL CONTENT FOR PEM BASED WATER ELECTROLYSIS 4 have also been studied. It has been shown that (Ir0.40Sn0.30Nb0.30)O2 shows similar electrochemical activity and enhanced chemical robustness as compared to pure IrO2. F doping of the ternary (Ir,Sn,Nb)O2 catalyst helps in further decreasing the noble metal oxide content of the catalyst. As a result, these reduced noble metal oxide catalyst systems would

  15. Designing supported palladium-on-gold bimetallic nano-catalysts for controlled hydrogenation of acetylene in large excess of ethylene

    Science.gov (United States)

    Malla, Pavani

    Ethylene is used as a starting point for many chemical intermediates in the petrochemical industry. It is predominantly produced through steam cracking of higher hydrocarbons (ethane, propane, butane, naphtha, and gas oil). During the cracking process, a small amount of acetylene is produced as a side product. However, acetylene must be removed since it acts as a poison for ethylene polymerization catalysts at even ppm concentrations (>5 ppm). Thus, the selective hydrogenation of acetylene to ethylene is an important process for the purification of ethylene. Conventional, low weight loading Pd catalysts are used for this selective reaction in high concentration ethylene streams. Gold was initially considered to be catalytically inactive for a long time. This changed when gold was seen in the context of the nanometric scale, which has indeed shown it to have excellent catalytic activity as a homogeneous or a heterogeneous catalyst. Gold is proved to have high selectivity to ethylene but poor at conversion. Bimetallic Au and Pd catalysts have exhibited superior activity as compared to Pd particles in semi-hydrogenation. Hydrogenation of acetylene was tested using this bimetallic combination. The Pd-on-Au bimetallic catalyst structure provides a new synthesis approach in improving the catalytic properties of monometallic Pd materials. TiO 2 as a support material and 0.05%Pd loading on 1%Au on titania support and used different treatment methods like washing plasma and reduction between the two metal loadings and was observed under 2:1 ratio. In my study there were two set of catalysts which were prepared by a modified incipient wetness impregnation technique. Out of all the reaction condition the catalyst which was reduced after impregnating gold and then impregnating palladium which was further treated in non-thermal hydrogen plasma and then pretreated in hydrogen till 250°C for 1 hour produced the best activity of 76% yield at 225°C. Stability tests were conducted

  16. Production of biodiesel by transesterification of soybean oil using calcium supported tin oxides as heterogeneous catalysts

    International Nuclear Information System (INIS)

    Highlights: • Heterogeneous catalysts were prepared by an impregnation method with different conditions. • The catalysts were efficient in the soybean oil transesterification. • The catalytic activity and stability of the catalyst were investigated. - Abstract: The main objective of this work was to develop an environmentally benign process for the production of biodiesel by using a stable solid base catalyst. To this purpose, different heterogeneous CaO–SnO2 catalysts have been prepared by means of impregnation methods. Various techniques such as X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric and differential thermal analysis (TG-DTA), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) were applied for the catalyst characterization. The transesterification of soybean oil with methanol, to produce biodiesel, was carried out under batch conditions at refluxed methanol over the CaO–SnO2 catalysts. The catalytic activity is found to be highly dependent on the Ca/Sn ratio and calcination temperature. The solid catalyst with the Ca/Sn molar ratio of 4:1 and calcined at a temperature of 973 K, performed the best activity, reaching the conversion to methyl esters of 89.3% after 6 h of reaction at methanol reflux temperature (343 K) when a methanol/oil molar ratio of 12:1 and catalyst dosage of 8 wt.% were employed. Further, the solid catalyst is proved to be stable and durable for the transesterification reaction

  17. Influence of the Synthesis Method for Pt Catalysts Supported on Highly Mesoporous Carbon Xerogel and Vulcan Carbon Black on the Electro-Oxidation of Methanol

    OpenAIRE

    Cinthia Alegre; María Elena Gálvez; Rafael Moliner; María Jesús Lázaro

    2015-01-01

    Platinum catalysts supported on carbon xerogel and carbon black (Vulcan) were synthesized with the aim of investigating the influence of the characteristics of the support on the electrochemical performance of the catalysts. Three synthesis methods were compared: an impregnation method with two different reducing agents, sodium borohydride and formic acid, and a microemulsion method, in order to study the effect of the synthesis method on the physico-chemical properties of the catalysts. X-ra...

  18. A core-shell structured, metal-ceramic composite-supported Ru catalyst for methane steam reforming

    Science.gov (United States)

    Lee, Hyun Chul; Potapova, Yulia; Lee, Doohwan

    2012-10-01

    Methane steam reforming on a metal-ceramic composite-supported ruthenium catalyst is studied at high temperatures. The core-shell structured Al2O3@Al composite consisting primarily of an Al metal core with a high surface area γ-Al2O3 overlayer is obtained by hydrothermal oxidation. Under the synthesis condition, primary Al2O3@Al particles aggregate to form a hierarchal secondary structure with macrosize inter-pores. This core-shell composite support enhances the heat conductivity and provides a high surface area for fine dispersion of a catalytic Ru component on the γ-Al2O3 overlayer. The Ru/Al2O3@Al catalyst exhibits significantly higher CH4 conversion than the conventional Ru/Al2O3 catalyst, indicating its superior properties for methane steam reforming at high temperatures contributed due to the fine Ru dispersion and facilitated heat and mass transfer via the unique catalyst structure. This metal-ceramic composite catalyst is stable in the reforming reaction for an extended time, suggesting reasonable stability in its physicochemical properties.

  19. Potassium-decorated active carbon supported Co-Mo-based catalyst for water-gas shift reaction

    Institute of Scientific and Technical Information of China (English)

    Yixin Lian; RuiFen Xiao; Weiping Fang; Yiquan Yang

    2011-01-01

    The effect of potassium-decoration was studied on the activity of water-gas shift(WGS)reaction over the Co-Mo-based catalysts supported on active carbon(AC),which was prepared by incipient wetness co-impregnation method.The decoration of potassium on active carbon in advance enhances the activities of the CoMo-K/AC catalysts for WGS reaction.Highest activity(about 92% conversion)was obtained at250 ℃ for the catalyst with an optimum K2O/AC weight ratio in the range from 0.12 to 0.15.The catalysts were characterized by TPR and EPR,and the results show that activated carbon decorated with potassium makes Co-Mo species highly dispersed,and thus easily reduced and sulfurized.XRD results show that an appropriate content of potassium-decoration on active carbon supports may favors the formation of highly dispersed Co9Ss-type structures which are situated on the edge or a site in contact with MoS2,K-Mo-O-S,Mo-S-K phase.Those active species are responsible for the high activity of CoMo-K/AC catalysts.

  20. Rational design of Mg-Al mixed oxide-supported bimetallic catalysts for dry reforming of methane

    Energy Technology Data Exchange (ETDEWEB)

    Tsyganok, Andrey I. [Centre for Catalysis Research and Innovation, Department of Chemistry, University of Ottawa, D' Iorio Hall, 10 Marie Curie Street, Ottawa, Ont. (Canada); Inaba, Mieko [Natural Gas Technology Development Team, Teikoku Oil Co., 9-23-30 Kitakarasuyama, Setagaya-ku, Tokyo 157-0061 (Japan); Tsunoda, Tatsuo; Uchida, Kunio; Suzuki, Kunio; Hayakawa, Takashi [Institute for Materials and Chemical Process, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 5, 1-1-1 Higashi, Tsukuba 305-8565 (Japan); Takehira, Katsuomi [Department of Applied Chemistry, Faculty of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima 739-8527 (Japan)

    2005-09-18

    A novel synthetic strategy for preparing bimetallic Ru-M (M=Cr, Fe, Co, Ni and Cu) catalysts, supported on Mg-Al mixed oxide, has been introduced. It was based on a 'memory effect', i.e. on the ability of Mg-Al mixed oxide to reconstruct a layered structure upon rehydration with an aqueous solution. By repeated calcinations-rehydration cycles, layered double hydroxide (LDH) precursors of catalysts containing two different metals were synthesized. Bimetallic catalysts were then generated (1) in situ from LDH under methane reforming reaction conditions and (2) from mixed metal oxides obtained by preliminary LDH calcination. Among all the LDH-derived catalysts, a Ru{sup 0.1%}-Ni{sup 5.0%}/MgAlO{sub x} sample revealed the highest activity and selectivity to syngas, a suitable durability and a low coking capacity. A promoting effect of ruthenium on catalytic function of supported nickel was demonstrated. Preliminary LDH calcination was shown to markedly affect the catalytic activity of the derived catalysts and especially their coking properties.

  1. Effects of supported metallocene catalyst active center multiplicity on antioxidant-stabilized ethylene homo- and copolymers

    KAUST Repository

    Atiqullah, Muhammad

    2014-10-09

    © 2014 Akadémiai Kiadó, Budapest, Hungary. A silica-supported bis(n-butylcyclopentadienyl) zirconium dichloride [( n BuCp)2ZrCl2] catalyst was synthesized. This was used to prepare an ethylene homopolymer and an ethylene-1-hexene copolymer. The active center multiplicity of this catalyst was modeled by deconvoluting the copolymer molecular mass distribution and chemical composition distribution. Five different active site types were predicted, which matched the successive self-nucleation and annealing temperature peaks. The thermo-oxidative melt stability, with and without Irganox 1010 and Irgafos 168, of the above polyethylenes was investigated using nonisothermal differential scanning calorimetric (DSC) experiments at 150 °C. This is a temperature that ensures complete melting of the samples and avoids the diffusivity of oxygen to interfere into polyethylene crystallinity and its thermo-oxidative melt degradation. The oxidation parameters such as onset oxidation temperature, induction period, protection factor, and S-factor were determined by combining theoretical modeling with the DSC experiments. Subsequently, these findings were discussed considering catalyst active center multiplicity and polymer microstructure, particularly average ethylene sequence length. Several insightful results, which have not been reported earlier in the literature, were obtained. The antioxidant effect, for each polymer, varied as (Irganox + Irgafos) ≈ Irganox > Irgafos > Neat polymer. The as-synthesized homopolymer turned out to be almost twice as stable as the corresponding copolymer. The antioxidant(s) in the copolymer showed higher antioxidant effectiveness (AEX) than those in the homopolymer. Irganox exhibited more AEX than Irgafos. To the best of our knowledge, such findings have not been reported earlier in the literature. However, mixed with Irganox or Irgafos, their melt oxidation stability was comparable. The homopolymer, as per the calculated S-factor, showed Irganox

  2. A Phenomenological Study on the Synergistic Role of Precious Metals and the Support in the Steam Reforming of Logistic Fuels on Monometal Supported Catalysts

    Directory of Open Access Journals (Sweden)

    Abdul-Majeed Azad

    2010-01-01

    Full Text Available Clean power source utilizing vast logistic fuel reserves (jet fuels, diesel, and coal would be the main driver in the 21st century for high efficiency. Fuel processors are required to convert these fuels into hydrogen-rich reformate for extended periods in the presence of sulfur, and deliver hydrogen with little or no sulfur to the fuel cell stack. However, the jet and other logistic fuels are invariably sulfur-laden. Sulfur poisons and deactivates the reforming catalyst and therefore, to facilitate continuous uninterrupted operation of logistic fuel processors, robust sulfur-tolerant catalysts ought to be developed. New noble metal-supported ceria-based sulfur-tolerant nanocatalysts were developed and thoroughly characterized. In this paper, the performance of single metal-supported catalysts in the steam-reforming of kerosene, with 260 ppm sulfur is highlighted. It was found that ruthenium-based formulation provided an excellent balance between hydrogen production and stability towards sulfur, while palladium-based catalyst exhibited rapid and steady deactivation due to the highest propensity to sulfur poisoning. The rhodium supported system was found to be most attractive in terms of high hydrogen yield and long-term stability. A mechanistic correlation between the role of the nature of the precious metal and the support for generating clean desulfurized H2-rich reformate is discussed.

  3. Hydroxyapatite supported caesium carbonate as a new recyclable solid base catalyst for the Knoevenagel condensation in water

    Directory of Open Access Journals (Sweden)

    Monika Gupta

    2009-11-01

    Full Text Available The Knoevenagel condensation between aromatic aldehydes and malononitrile, ethyl cyanoacetate or malonic acid with hydroxyapatite supported caesium carbonate in water is described. HAP–Cs2CO3 was found to be a highly active, stable and recyclable catalyst under the reaction conditions.

  4. Hydroxyapatite supported caesium carbonate as a new recyclable solid base catalyst for the Knoevenagel condensation in water

    OpenAIRE

    Monika Gupta; Rajive Gupta; Medha Anand

    2009-01-01

    The Knoevenagel condensation between aromatic aldehydes and malononitrile, ethyl cyanoacetate or malonic acid with hydroxyapatite supported caesium carbonate in water is described. HAP–Cs2CO3 was found to be a highly active, stable and recyclable catalyst under the reaction conditions.

  5. One-step Synthesis of n-Butanol from Ethanol Condensation over Alumina-supported Metal Catalysts

    Institute of Scientific and Technical Information of China (English)

    Ke Wu YANG; Xuan Zhen JIANG; Wei Chao ZHANG

    2004-01-01

    One-step synthesis of n-butanol from bimolecular condensation of ethanol was firstly achieved over nickel supported gamma alumina catalyst. A mechanism of dehydration path for the growth of carbon chain by eliminating a hydroxy group from one ethanol molecule with a α-H of other ethanol molecule rather than aldol condensation was verified.

  6. Synthesis and characterization of molybdenum catalysts supported on γ-Al2O3-CeO2 composite oxides

    International Nuclear Information System (INIS)

    The physical and chemical properties of a catalyst play a vital role in various industrial applications. Molybdenum catalysts supported on γ-Al2O3 and γ-Al2O3-CeO2 mixed oxides with varying loading of CeO2 (5, 10, 15, 20 wt% with respect to γ-Al2O3) were prepared by wet impregnation method. The physiochemical properties of these synthesized Mo catalysts were studied with various characterization techniques such as X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), temperature-programmed reduction (TPR), field emission scanning electron microscopy-energy dispersive analysis (FESEM-EDX) and X-ray fluorescence spectrometer (XRF). The results showed that the addition of CeO2 into the support affected the binding energies of the elements and reducibility of the metal oxides formed after calcination of catalyst samples due to the change in metal-support interaction. Further, the characterization techniques showed that the active metal was well dispersed on the surface of support material.

  7. Synthesis and characterization of molybdenum catalysts supported on γ-Al2O3-CeO2 composite oxides

    Science.gov (United States)

    Farooq, Muhammad; Ramli, Anita; Subbarao, Duvvuri

    2012-09-01

    The physical and chemical properties of a catalyst play a vital role in various industrial applications. Molybdenum catalysts supported on γ-Al2O3 and γ-Al2O3-CeO2 mixed oxides with varying loading of CeO2 (5, 10, 15, 20 wt% with respect to γ-Al2O3) were prepared by wet impregnation method. The physiochemical properties of these synthesized Mo catalysts were studied with various characterization techniques such as X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), temperature-programmed reduction (TPR), field emission scanning electron microscopy-energy dispersive analysis (FESEM-EDX) and X-ray fluorescence spectrometer (XRF). The results showed that the addition of CeO2 into the support affected the binding energies of the elements and reducibility of the metal oxides formed after calcination of catalyst samples due to the change in metal-support interaction. Further, the characterization techniques showed that the active metal was well dispersed on the surface of support material.

  8. Selective Aerobic Oxidation of 5-Hydroxymethylfurfural in Water Over Solid Ruthenium Hydroxide Catalysts with Magnesium-Based Supports

    DEFF Research Database (Denmark)

    Gorbanev, Yury; Kegnæs, Søren; Riisager, Anders

    2011-01-01

    Solid catalyst systems comprised of ruthenium hydroxide supported on magnesium-based carrier materials (spinel, magnesium oxide and hydrotalcite) were investigated for the selective, aqueous aerobic oxidation of the biomass-derived chemical 5-hydroxymethylfurfural into 2,5-furandicarboxylic acid...

  9. Characterization and parametrical study of Rh-TPPTS supported ionic liquid phase (SILP) catalysts for ethylene hydroformylation

    DEFF Research Database (Denmark)

    Hanh, Nguyen Thi Ha; Duc, Duc Truong; Thang, Vu Dao;

    2012-01-01

    The supported ionic liquid phase (SILP) catalysis technology was applied to continuous, gas-phase hydroformylation of ethylene. Rh-TPPTS SILP catalysts with relatively low ionic liquid loading were shown to be stable and highly activity for ethylene hydroformylation. However, the catalytic activi...

  10. Ferric hydrogen sulfate supported on silica-coated nickel ferrite nanoparticles as new and green magnetically separable catalyst for 1,8-dioxodecahydroacridine synthesis

    Institute of Scientific and Technical Information of China (English)

    Amir Khojastehnezhad; Mohammad Rahimizadeh; Hossein Eshghi; Farid Moeinpour; Mehdi Bakavoli

    2014-01-01

    A new magnetically separable catalyst consisting of ferric hydrogen sulfate supported on sili-ca-coated nickel ferrite nanoparticles was prepared. The synthesized catalyst was characterized using vibrating sample magnetometry, X-ray diffraction, transmission electron microscopy, scan-ning electron microscopy, and Fourier transform infrared spectroscopy. This new magnetic catalyst was shown to be an efficient heterogeneous catalyst for the synthesis of 1,8- dioxodecahydroacri-dines under solvent-free conditions. The catalyst is readily recovered by simple magnetic decanta-tion and can be recycled several times with no significant loss of catalytic activity.

  11. Inkjet printing of carbon supported platinum 3-D catalyst layers for use in fuel cells

    Science.gov (United States)

    Taylor, André D.; Kim, Edward Y.; Humes, Virgil P.; Kizuka, Jeremy; Thompson, Levi T.

    We present a method of using inkjet printing (IJP) to deposit catalyst materials onto gas diffusion layers (GDLs) that are made into membrane electrode assemblies (MEAs) for polymer electrolyte fuel cell (PEMFC). Existing ink deposition methods such as spray painting or screen printing are not well suited for ultra low (Monarch 700, Black Pearls 2000, etc.). Our ink jet printed MEAs with catalyst loadings of 0.020 mg Pt cm -2 have shown Pt utilizations in excess of 16,000 mW mg -1 Pt which is higher than our traditional screen printed MEAs (800 mW mg -1 Pt). As a further demonstration of IJP versatility, we present results of a graded distribution of Pt/C catalyst structure using standard Johnson Matthey (JM) catalyst. Compared to a continuous catalyst layer of JM Pt/C (20% Pt), the graded catalyst structure showed enhanced performance.

  12. Suzuki Reaction of Aryl Bromides Using a Phosphine-Free Magnetic Nanoparticle-Supported Palladium Catalyst

    Institute of Scientific and Technical Information of China (English)

    Nghia T. BUI; Trung B. DANG; Ha V. LE; Nam T. S. PHAN

    2011-01-01

    A palladium catalyst immobilized on superparaganetic nanoparticles was prepared with a palladium loading of 0.30 mmol/g.The catalyst was characterized using X-ray diffraction,scanning electron microscopy,transmission electron microscopy,vibrating sample magnetometry,thermogravimetric analysis,Fourier transform infrared,atomic absorption spectrophotometry,and nitrogen adsorption.The immobilized palladium catalyst was an efficient catalyst without added phosphine ligands for the Suzuki cross-coupling reaction of several aryl bromides with phenylboronic acid.The recovery of catalyst was simply by magnetic decantation in the presence of a magnet.The immobilized palladium catalyst can be reused many times without significant degradation in catalytic activity.No leaching of active palladium species into the reaction solution was detected.

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

    OpenAIRE

    Ling Fei; Harvind Kumar Reddy; Joshua Hill; Qianglu Lin; Bin Yuan; Yun Xu; Peter Dailey; Shuguang Deng; Hongmei Luo

    2012-01-01

    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 est...

  14. Characterization of platinum catalyst supported on carbon nanoballs prepared by solution plasma processing

    International Nuclear Information System (INIS)

    In order to improve the energy-conversion efficiency in fuel cells, the authors loaded Pt nanoparticles on carbon nanoballs (CNBs) by using solution plasma processing (SPP) involving CNB and Pt ion with a protection group. In this study, we employed poly(vinylpyrrolidone) (PVP) or sodium dodecyl sulfate (SDS) to prepare Pt nanoparticles supported on CNB (Pt/CNB) by the SPP, and the electrochemical properties as a catalyst was evaluated by cyclic voltammetry. The carbon nanoballs were prepared by thermal decomposition process of ethylene and hydrogen gases. Color of the solution changed from yellow to dark brown as synthesis time. This change indicates the improvement of dispersibility of CNB. Moreover, transmission electron microscopy images and elemental mapping images showed the Pt nanoparticles supported on CNB. A catalytic activity of the Pt/CNB in use of SDS was shown to be higher than the Pt/CNB prepared with PVP system. The SDS-containing Pt/CNB also showed the higher activity than that obtained by the conventional method.

  15. Oxidation of methanol to formaldehyde on supported vanadium oxide catalysts compared to gas phase molecules.

    Science.gov (United States)

    Döbler, Jens; Pritzsche, Marc; Sauer, Joachim

    2005-08-10

    The oxidation of methanol to formaldehyde on silica supported vanadium oxide is studied by density functional theory. For isolated vanadium oxide species silsesquioxane-type models are adopted. The first step is dissociative adsorption of methanol yielding CH3O(O=)V(O-)2 surface complexes. This makes the O=V(OCH3)3 molecule a suited model system. The rate-limiting oxidation step involves hydrogen transfer from the methoxy group to the vanadyl oxygen atom. The transition state is biradicaloid and needs to be treated by the broken-symmetry approach. The activation energies for O=V(OCH3)3 and the silsesquioxane surface model are 147 and 154 kJ/mol. In addition, the (O=V(OCH3)3)(2) dimer (a model for polymeric vanadium oxide species) and the O=V(OCH3)3(*+) radical cation are studied. For the latter the barrier is only 80 kJ/mol, indicating a strong effect of the charge on the energy profile of the reaction and questioning the significance of gas-phase cluster studies for understanding the activity of supported oxide catalysts.

  16. Effect of catalyst pretreatment on the olefin metathesis catalyzed by alumina-supported (9%) rhenium oxide

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, J.C.

    1979-01-01

    A kinetic model was developed to express the time-on-stream profile of the activity during catalyst break-in and deactivation. The catalyst surface is in geometric and energetic heterogeneity. Partial catalyst reduction is a prerequisite step for olefin metathesis. The metathesis activity may be affected by the coordination number and the type of ligands associated with the sites on the catalyst. The deactivation is proposed due to deposition of residues on the active sites, and to sintering, etc. A dispersion pretreatment increased activity. Oxygen is an activator. The hydrogen reduction at 500/sup 0/C causes partial but permanent loss of activity.

  17. Suppression of methane formation during Fisher-Tropsch synthesis using manganese-cobalt oxide supported on H-5A zeolite as a catalyst

    Institute of Scientific and Technical Information of China (English)

    Syed Tajammul Hussain; Muhammad Mazhar; Muhammad Arif Nadeem

    2009-01-01

    In Fischer-Tropsch synthesis reaction, methane formation is one of the side reactions which must be suppressed in order to get better catalytic selectivity for light olefins. In the present study, we have modified cobalt based Fischer-Tropsch catalyst and developed a process to minimize methane production, consequently to produce maximum yield of light olefins. Manganese-cobalt oxide supported on H-5A zeolite catalyst was synthesized using modified H-5A zeolite, to increase its surface acid sites. Increased acidity of zeolite plays a major part in the suppression of methane formation during the Fischer-Tropsch reaction. The modified zeolite results in the electronic modification of catalyst surface by creating new active catalytic sites. The results are compared with other supported catalysts along with unmodified zeolite. Appreciable reduction in methane formation is achieved on modified zeolite supported catalyst in comparison with unsupported catalyst.

  18. Vanadium Oxide Supported on MSU-1 as a Highly Active Catalyst for Dehydrogenation of Isobutane with CO2

    OpenAIRE

    Guosong Sun; Qingze Huang; Shiyong Huang; Qiuping Wang; Huiquan Li; Haitao Liu; Shijie Wan; Xuewang Zhang; Jinshu Wang

    2016-01-01

    Vanadium oxide supported on MSU-1, with VOx loading ranging from 2.5 to 17.5 wt. %, was developed as a highly active catalyst in dehydrogenation of isobutane with CO2. The obtained catalysts of VOx/MSU-1 were characterized by X-ray diffraction (XRD), N2 adsorption-desorption, and H2-temperature programmed reduction (H2-TPR) methods and the results showed that the large surface area of MSU-1 was favorable for the dispersion of VOx species and the optimal loading of VOx was 12.0 wt. %. Meanwhil...

  19. Effective immobilisation of a metathesis catalyst bearing an ammonium-tagged NHC ligand on various solid supports

    Directory of Open Access Journals (Sweden)

    Krzysztof Skowerski

    2016-01-01

    Full Text Available An ammonium-tagged ruthenium complex, 8, was deposited on several widely available commercial solid materials such as silica gel, alumina, cotton, filter paper, iron powder or palladium on carbon. The resulting catalysts were tested in toluene or ethyl acetate, and found to afford metathesis products in high yield and with extremely low ruthenium contamination. Depending on the support used, immobilised catalyst 8 shows also additional traits, such as the possibility of being magnetically separated or the use for metathesis and subsequent reduction of the obtained double bond in one pot.

  20. The Selective Oxidation of n-Butane to Maleic Anhydride : Comparison of Bulk and Supported V-P-O Catalysts

    OpenAIRE

    Koningsberger, D.C.; Ruitenbeek, M.; van Dillen, A.J.; BARBON, A; Faassen, E.E.H. van; Geus, John W.

    1998-01-01

    V P O catalysts supported on the surface of silica and titania particles were studied and compared with bulk V P O. The catalytic performance was tested in the n-butane oxidation reaction to maleic anhydride, and the structure of the equilibrated catalysts was characterised with X-ray absorption spectroscopy (EXAFS) and (low-temperature) ESR spectroscopy. Our results show considerable differences in catalytic performance between VPO/TiO_{2} on the one hand, and VPO/SiO_{2} and VPO/bulk on the...

  1. Fundamental Studies of Butane Oxidation over Model-Supported Vanadium Oxide Catalysts: Molecular Structure-Reactivity Relationships

    NARCIS (Netherlands)

    Wachs, I.E.; Jehng, J.M.; Deo, G.; Weckhuysen, B.M.; Guliants, V.V.; Benziger, J.B.; Sundaresan, S.

    1997-01-01

    The oxidation of n-butane to maleic anhydride was investigated over a series of model-supported vanadia catalysts where the vanadia phase was present as a two-dimensional metal oxide overlayer on the different oxide supports (TiO2, ZrO2, CeO2, Nb2O5, Al2O3, and SiO2). No correlation was found betwee

  2. Supported cobalt oxide on graphene oxide: Highly efficient catalysts for the removal of Orange II from water

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Penghui, E-mail: sph1123@163.com [College of Environment Science and Engineering, Donghua University, Shanghai 201620 (China); Henan University of Urban Construction, Pingdingshan, Henan 467044 (China); Su, Ruijing; Zhu, Shaobo [College of Environment Science and Engineering, Donghua University, Shanghai 201620 (China); Zhu, Mincong [College of Environment Science and Engineering, Donghua University, Shanghai 201620 (China); Department of Chemistry and Environmental Science, Zhangzhou Normal University, Zhangzhou, Fujian 363000 (China); Li, Dengxin, E-mail: lidengxin@dhu.edu.cn [College of Environment Science and Engineering, Donghua University, Shanghai 201620 (China); Xu, Shihong [College of Environment Science and Engineering, Donghua University, Shanghai 201620 (China)

    2012-08-30

    Highlights: Black-Right-Pointing-Pointer Cobalt oxide supported on graphene oxide (GO) in a solvothermal system. Black-Right-Pointing-Pointer The structure of the Co{sub 3}O{sub 4}/GO catalyst is stable and the well-dispersed Co{sub 3}O{sub 4} particles on GO. Black-Right-Pointing-Pointer The Co{sub 3}O{sub 4}/GO catalyst is an efficient heterogeneous catalyst for activation of PMS. Black-Right-Pointing-Pointer The Co{sub 3}O{sub 4}/GO/PMS system is able to completely degrade Orange II within a very short duration of a few minutes. Black-Right-Pointing-Pointer Very limited cobalt dissolved from Co{sub 3}O{sub 4}/GO. - Abstract: The current paper investigated the removal of the azo dye Orange II from water using advanced oxidation processes based on sulfate radicals. The cobalt oxide catalyst immobilized on graphene oxide (GO) can activate peroxymonosulfate (PMS) for the degradation of Orange II in water. The Co{sub 3}O{sub 4}/GO catalyst system was characterized via X-ray diffraction, Fourier transform infrared spectroscopy, Raman spectroscopy, scanning electron microscopy, and X-ray spectroscopy. Results showed that Co{sub 3}O{sub 4} was distributed on GO. The Co{sub 3}O{sub 4}/GO catalyst system exhibited high activity in Orange II oxidation when the Co{sub 3}O{sub 4}/GO catalyst has an optimum Co{sub 3}O{sub 4} loading. In addition, 100% decomposition could be achieved within 6 min with 0.2 mM Orange II, 0.1 g L{sup -1} catalyst, and 2 mM PMS. Meanwhile, inductively coupled plasma analysis revealed that the leach of cobalt ions was low. The catalyst also exhibited stable performance after several rounds of regeneration. Several operational parameters, such as catalyst amount, oxidant amount, pH, temperature, and oxidation rate, affected the degradation of Orange II.

  3. Co-production of hydrogen and carbon nanofibers from methane decomposition over zeolite Y supported Ni catalysts

    International Nuclear Information System (INIS)

    Highlights: • Methane cracking requires an optimum temperature range of 550–600 °C for H2 yield. • At 550 and 600 °C, catalyst showed longer activity for the whole test. • At 600 °C, a 614.25 gc/gNi of carbon was obtained using 30% Ni/Y zeolite catalysts. • Produced filamentous carbon has the same diameter as the metallic nickel itself. • VHSV has reverse and non-linear relevancy to the weight of Ni/Y zeolite catalyst. - Abstract: The objective of this paper is to study the influences of different operating conditions on the hydrogen formation and properties of accumulated carbon from methane decomposition using zeolite Y supported 15% and 30% Ni, respectively, at a temperature range between 500 and 650 °C in a pilot scale fixed bed reactor. The temperature ramp was showed a significant impact on the thermo-catalytic decomposition (TCD) of methane. An optimum temperature range of 550–600 °C were required to attain the maximum amount of methane conversion and revealed that at 550 and 600 °C, catalyst showed longer activity for the whole studied of experimental runs. Additionally, at 550 °C, the methane decomposition is two times longer for 30% Ni/Y zeolite than that for 15% Ni/Y zeolite catalyst, whereas it is almost three times higher at 500 °C. A maximum carbon yield of 614.25 and 157.54 gc/gNi were reported after end of the complete reaction at 600 °C with 30% and 15% Ni/Y zeolite catalyst, respectively. From BET, TPD, and XRD analysis, we had reported that how the chemistry between the TCD of methane and metal content of the catalysts could significantly affect the hydrogen production as well as carbon nano-fibers. TEM analysis ensured that the produced carbon had fishbone type structures with a hollow core and grew from crystallites of Ni anchored on the external surface of the catalysts and irrespective of the metal loadings, the whisker types of nano filaments were formed as confirmed from FESEM analysis. Nevertheless, the effect of

  4. Steam reforming of ethanol over Ni/support catalysts for generation of hydrogen for fuel cell applications

    Energy Technology Data Exchange (ETDEWEB)

    Denis, Andrzej; Grzegorczyk, Wieslaw; Gac, Wojciech; Machocki, Andrzej [University of Maria Curie-Sklodowska, Faculty of Chemistry, Department of Chemical Technology, 3 Maria Curie-Sklodowska Square, 20-031 Lublin (Poland)

    2008-09-30

    The paper reports experimental results concerning the influence of the support nature (TiO{sub 2}, ZnO, Al{sub 2}O{sub 3} and Al{sub 2}O{sub 3}-Fe{sub 2}O{sub 3}) of nickel catalysts on their activity, selectivity and coking phenomenon in the steam reforming of ethanol in the range of 570-870K. The chemical transformations of ethanol occurring on the catalyst support make its chemical nature an important factor affecting the productivity and selectivity of the process. It was found that the most suitable supports in nickel catalysts designed for hydrogen generation in the steam reforming of ethanol are ZnO and TiO{sub 2}. Taking into consideration both the efficiency of hydrogen generation and the intensity of carbon deposition, the optimum temperature of the process of the steam reforming of ethanol is below 750K. An improvement in the selectivity of hydrogen generation and diminishing of the formation of undesirable products may be obtained by promoting nickel catalysts with sodium. (author)

  5. Boron-doped graphene as promising support for platinum catalyst with superior activity towards the methanol electrooxidation reaction

    Science.gov (United States)

    Sun, Yongrong; Du, Chunyu; An, Meichen; Du, Lei; Tan, Qiang; Liu, Chuntao; Gao, Yunzhi; Yin, Geping

    2015-12-01

    We report the synthesis of boron-doped graphene by thermally annealing the mixture of graphene oxide and boric acid, and its usage as the support of Pt catalyst towards the methanol oxidation reaction. The composition, structure and morphology of boron-doped graphene and its supported Pt nanoparticles (Pt/BG) are characterized by transmission electron microscopy, inductively coupled plasma mass spectrometry, Raman spectroscopy, X-ray diffraction and X-ray photoelectron spectroscopy. It is revealed that boron atoms are doped into graphene network in the form of BC2O and BCO2 bonds, which lead to the increase in defect sites and facilitate the subsequent deposition of Pt nanoparticles. Therefore, the Pt/BG catalyst presents smaller particle size and narrower size distribution than the graphene supported Pt (Pt/G) catalyst. When evaluated as the electrocatalyst for the methanol oxidation reaction, the Pt/BG catalyst exhibits excellent electrochemical activity and stability demonstrated by cyclic voltammetry and chronoamperometry tests. The enhanced activity is mainly ascribed to the electronic interaction between boron-doped graphene and Pt nanoparticles, which lowers the d-band center of Pt and thus weakens the absorption of the poisoning intermediate CO. Our work provides an alternative approach of improving the reaction kinetics for the oxidation of small organic molecules.

  6. Gold catalysts supported on nanosized iron oxide for low-temperature oxidation of carbon monoxide and formaldehyde

    Science.gov (United States)

    Tang, Zheng; Zhang, Weidong; Li, Yi; Huang, Zuming; Guo, Huishan; Wu, Feng; Li, Jinjun

    2016-02-01

    This study aimed to optimize synthesis of gold catalyst supported on nanosized iron oxide and to evaluate the activity in oxidation of carbon monoxide and formaldehyde. Nanosized iron oxide was prepared from a colloidal dispersion of hydrous iron oxide through a dispersion-precipitation method. Gold was adsorbed onto nanosized iron oxide under self-generated basic conditions. Characterization results indicate that the iron oxide consisted of hematite/maghemite composite with primary particle sizes of 6-8 nm. Gold was highly dispersed on the surface of the support. The catalysts showed good activity in the oxidation of airborne carbon monoxide and formaldehyde. The optimal pH for their synthesis was ∼7. The catalytic performance could be enhanced by extending the adsorption time of gold species on the support within 21 h. The optimized catalyst was capable of achieving complete oxidation of 1% carbon monoxide at -20 °C and 33% conversion of 450 ppm formaldehyde at ambient temperature. The catalyst may be applicable to indoor air purification.

  7. Activated Carbons as Supports for Catalyst%作为催化剂载体的活性炭

    Institute of Scientific and Technical Information of China (English)

    赵波; 韩文锋; 霍超; 刘化章

    2004-01-01

      This paper introduces the advantages of activated carbons as supports for catalysts. The manufacture of the carbons is described briefly, together with their most important chemical and physical properties that are tightly related to catalysts manufacture and use of such catalysts. The treatment methods of activated carbons are also reviewed.%  介绍了活性炭作为催化剂载体的优点、了活性炭的生产方法以及与催化剂的生产和应用密切相关的活性炭的物理及化学性质,并介绍了活性炭的改性处理的方法。

  8. Carbon supported Cu-Pd nanoparticles as anode catalyst for direct borohydride-hydrogen peroxide fuel cells

    International Nuclear Information System (INIS)

    Carbon supported Cu-Pd bimetallic nanoparticles were prepared by a successive reduction method in aqueous solution and used as anode electrocatalyst for direct borohydride-hydrogen peroxide fuel cell (DBHFC). The physical and electrochemical properties of the as-prepared electrocatalysts are investigated by transmission electron microscopy (TEM), X-ray diffraction (XRD), cyclic voltammetry (CV), chronopotentiometry (CP), linear sweep voltammetry (LSV) and fuel cell test. The results show that the size of the crystallite is around 12.5 nm, the Cu1Pd1/C catalyst presents the highest catalytic activity among all the resultant catalysts, and the DBHFC using Cu1Pd1/C as anode catalyst and Pt mesh (1 cm × 1 cm) as cathode electrode obtains the maximum power density as high as 39.8 mW cm-2 at a discharge current density of 80.1 mA cm-2 at 20 °C

  9. Ruthenium carbenes supported on mesoporous silicas as highly active and selective hybrid catalysts for olefin metathesis reactions under continuous flow.

    Science.gov (United States)

    Bru, Miriam; Dehn, Richard; Teles, J Henrique; Deuerlein, Stephan; Danz, Manuel; Müller, Imke B; Limbach, Michael

    2013-08-26

    In the search for a highly active and selective heterogenized metathesis catalyst, we systematically varied the pore geometry and size of various silica-based mesoporous (i.e., MCM-41, MCM-48, and SBA-15) and microporous (ZSM-5 and MWW) versus macroporous materials (D11-10 and Aerosil 200), besides other process parameters (temperature, dilution, and mean residence time). The activity and, especially, selectivity of such "linker-free" supports for ruthenium metathesis catalysts were evaluated in the cyclodimerization of cis-cyclooctene to form 1,9-cyclohexadecadiene, a valuable intermediate in the flavor and fragrance industry. The optimized material showed not only exceptionally high selectivity to the valuable product, but also turned out to be a truly heterogeneous catalyst with superior activity relative to the unsupported homogeneous complex.

  10. Ultrasonically treated multi-walled carbon nanotubes (MWCNTs) as PtRu catalyst supports for methanol electrooxidation

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Chunwei; Hu, Xinguo; Wang, Dianlong; Dai, Changsong [Department of Applied Chemistry, Harbin Institute of Technology, Harbin 150001 (China); Zhang, Liang; Jin, Haibo [School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081 (China); Agathopoulos, Simeon [Department of Materials Science and Engineering, University of Ioannina, GR-451 10 Ioannina (Greece)

    2006-09-29

    In the quest of fabricating supported catalysts, experimental results of transmission electron microscopy, Raman and infrared spectroscopy indicate that ultrasonic treatment effectively functionalizes multi-walled carbon nanotubes (MWCNTs), endowing them with groups that can act as nucleation sites which can favor well-dispersed depositions of PtRu clusters on their surface. Ultrasonic treatment seems to be superior than functionalization via regular refluxing. This is confirmed by the determination of the electrochemistry active surface area (ECA) and the CO-tolerance performance of the PtRu catalysts, measured by adsorbed CO-stripping voltammetry in 0.5M sulfuric acid solution, and the real surface area of the PtRu catalysts, evaluated by Brunauer-Emmett-Teller (BET) measurements. Finally, the effectiveness for methanol oxidation is assessed by cyclic voltammetry (CV) in a sulfuric acid and methanol electrolyte. (author)

  11. Effect of reduction method on the performance of Pd catalysts supported on activated carbon for the selective oxidation of glucose

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The effect of the reduction method on the catalytic properties of palladium catalysts supported on activated carbon for the oxidation of D-glucose was examined.The reduction methods investigated include argon glow discharge plasma reduction at room temperature,reduction by flowing hydrogen at elevated temperature,and reduction by formaldehyde at room temperature.The plasma-reduced catalyst shows the smallest metal particles with a narrow size distribution that leads to a much higher activity.The catalyst characteristics show that the plasma reduction increases the amount of oxygen-containing functional groups,which significantly enhances the hydrophilic property of the activated carbon and improves the dispersion of the metal.

  12. Ruthenium carbenes supported on mesoporous silicas as highly active and selective hybrid catalysts for olefin metathesis reactions under continuous flow.

    Science.gov (United States)

    Bru, Miriam; Dehn, Richard; Teles, J Henrique; Deuerlein, Stephan; Danz, Manuel; Müller, Imke B; Limbach, Michael

    2013-08-26

    In the search for a highly active and selective heterogenized metathesis catalyst, we systematically varied the pore geometry and size of various silica-based mesoporous (i.e., MCM-41, MCM-48, and SBA-15) and microporous (ZSM-5 and MWW) versus macroporous materials (D11-10 and Aerosil 200), besides other process parameters (temperature, dilution, and mean residence time). The activity and, especially, selectivity of such "linker-free" supports for ruthenium metathesis catalysts were evaluated in the cyclodimerization of cis-cyclooctene to form 1,9-cyclohexadecadiene, a valuable intermediate in the flavor and fragrance industry. The optimized material showed not only exceptionally high selectivity to the valuable product, but also turned out to be a truly heterogeneous catalyst with superior activity relative to the unsupported homogeneous complex. PMID:23852995

  13. Kinetics and efficiency displayed by supported and suspended TiO2 catalysts applied to the disinfection of Escherichia coli

    Institute of Scientific and Technical Information of China (English)

    Majdi Kacem; Gael Plantard; Nathalie Wery; Vincent Goetz

    2014-01-01

    TiO2-mediated photocatalysis is widely used in a variety of applications and products in the envi-ronmental and energy fields, including photoelectrochemical conversion, self-cleaning surfaces, and especially water purification systems. The dimensionality of the structure of a TiO2 material can affect its properties, functions, and more specifically, its photocatalytic performance. In this work, the photocatalytic inactivation of Gram-negative Escherichia coli using three photocatalysts, differ-ing in their structure and other characteristics, was studied in a batch reactor under UVA light. The aim was to establish the disinfection efficiency of solid TiO2 compared with that of suspended cata-lysts, widely considered as reference cases for photocatalytic water disinfection. The bacterial inac-tivation profiles obtained showed that: (1) the photoinactivation was exclusively related to the quantity of photons retained per unit of treated volume, irrespective of the characteristics of the photocatalyst and the emitted light flux densities;(2) across the whole UV light range studied, each of the photocatalytic solids was able to achieve more than 2 log bacterial inactivation with less than 2 h UV irradiation;(3) none of the used catalysts achieved a total bacterial disinfection during the treatment time. For each of the catalysts the quantum yield has been assessed in terms of disinfec-tion efficiency, the 2D material showed almost the same performance as those of suspended cata-lysts. This catalyst is promising for supported photocatalysis applications.

  14. The effect of noble metals on catalytic methanation reaction over supported Mn/Ni oxide based catalysts

    Directory of Open Access Journals (Sweden)

    Wan Azelee Wan Abu Bakar

    2015-09-01

    Full Text Available Carbon dioxide (CO2 in sour natural gas can be removed using green technology via catalytic methanation reaction by converting CO2 to methane (CH4 gas. Using waste to wealth concept, production of CH4 would increase as well as creating environmental friendly approach for the purification of natural gas. In this research, a series of alumina supported manganese–nickel oxide based catalysts doped with noble metals such as ruthenium and palladium were prepared by wetness impregnation method. The prepared catalysts were run catalytic screening process using in-house built micro reactor coupled with Fourier Transform Infra Red (FTIR spectroscopy to study the percentage CO2 conversion and CH4 formation analyzed by GC. Ru/Mn/Ni(5:35:60/Al2O3 calcined at 1000 °C was found to be the potential catalyst which gave 99.74% of CO2 conversion and 72.36% of CH4 formation at 400 °C reaction temperature. XRD diffractogram illustrated that the supported catalyst was in polycrystalline with some amorphous state at 1000 °C calcination temperature with the presence of NiO as active site. According to FESEM micrographs, both fresh and used catalysts displayed spherical shape with small particle sizes in agglomerated and aggregated mixture. Nitrogen Adsorption analysis revealed that both catalysts were in mesoporous structures with BET surface area in the range of 46–60 m2/g. All the impurities have been removed at 1000 °C calcination temperature as presented by FTIR, TGA–DTA and EDX data.

  15. Recent progress of ordered mesoporous silica-supported chiral metallic catalysts

    Directory of Open Access Journals (Sweden)

    LIU Rui

    2013-02-01

    Full Text Available Recently,ordered silica-based mesoporous chiral organometallics-functionalized heterogeneous catalysts have attracted extensive research interest due to their excellent properties,such as easy preparation,high activity and convenient recycle.This review mainly summarizesthe generally prepared strategy and the silica-based organometallics-functionalized heterogeneous catalysts reported in the literatures.

  16. A conceptual translation of homogeneous catalysis into heterogeneous catalysis: homogeneous-like heterogeneous gold nanoparticle catalyst induced by ceria supporter.

    Science.gov (United States)

    Li, Zhen-Xing; Xue, Wei; Guan, Bing-Tao; Shi, Fu-Bo; Shi, Zhang-Jie; Jiang, Hong; Yan, Chun-Hua

    2013-02-01

    Translation of homogeneous catalysis into heterogeneous catalysis is a promising solution to green and sustainable development in chemical industry. For this purpose, noble metal nanoparticles represent a new frontier in catalytic transformations. Many challenges remain for researchers to transform noble metal nanoparticles of heterogeneous catalytic active sites into ionic species of homogeneous catalytic active sites. We report here a successful design on translating homogeneous gold catalysis into a heterogeneous system with a clear understanding of the catalytic pathway. This study initiates a novel concept to immobilize a homogeneous catalyst based on electron transfer between supporting base and supported nanoparticles. Meanwhile, on the basis of theoretical calculation, it has deepened the understanding of the interactions between noble metal nanoparticles and the catalyst support.

  17. Conversion of biomass-derived sorbitol to glycols over carbon-materials supported Ru-based catalysts

    Science.gov (United States)

    Guo, Xingcui; Guan, Jing; Li, Bin; Wang, Xicheng; Mu, Xindong; Liu, Huizhou

    2015-11-01

    Ruthenium (Ru) supported on activated carbon (AC) and carbon nanotubes (CNTs) was carried out in the hydrogenolysis of sorbitol to ethylene glycol (EG) and 1,2-propanediol (1,2-PD) under the promotion of tungsten (WOx) species and different bases. Their catalytic activities and glycols selectivities strongly depended on the support properties and location of Ru on CNTs, owning to the altered metal-support interactions and electronic state of ruthenium. Ru located outside of the tubes showed excellent catalytic performance than those encapsulated inside the nanotubes. Additionally, the introduction of WOx into Ru/CNTs significantly improved the hydrogenolysis activities, and a complete conversion of sorbitol with up to 60.2% 1,2-PD and EG yields was obtained on RuWOx/CNTs catalyst upon addition of Ca(OH)2. Stability study showed that this catalyst was highly stable against leaching and poisoning and could be recycled several times.

  18. Pillar effects in MoS2 catalysts supported on Al and Zr pillared clays in a hydrotreatment reaction

    International Nuclear Information System (INIS)

    Molybdenum (Mo) supported on aluminum-pillared clay (Al-PILC) and zirconium-pillared clay (Zr-PILC) with contents of 0.6, 1.4 and 2.8 atoms of Mo/nm2 were prepared and tested in the hydrogenation (HYD) of naphthalene (NP). It was found that the molybdenum sulfide (MoS2) catalysts supported on Zr- pillared clays were more active than the samples supported on Al-pillared clays and catalysts supported on alumina. The catalysts were characterized by X-ray diffraction (XRD), thermogravimetric analysis, nitrogen adsorption and transmission electron microscopy (TEM). Characterization analysis clearly pointed out to a close interaction of MoS2 with ZrO2 in the pillared clays. Therefore, the highest hydrogenation activities can be related to the presence of an interaction of MoS2 with ZrO2, probably with a different electronic interaction between the active phase and the support, than that reported for the MoS2/Al2O3 system

  19. Kinetics of oxygen-enhanced water gas shift on bimetallic catalysts and the roles of metals and support

    Science.gov (United States)

    Kugai, Junichiro

    The post-processing of reformate is an important step in producing hydrogen (H2) with low carbon monoxide (CO) for low temperature fuel cells from syn-gas. However, the conventional process consists of three steps, i.e. two steps of water gas shift (WGS) and preferential oxidation (PROX) of CO, and it is not suitable for mobile applications due to the large volume of water gas shift (WGS) catalysts and conditioning and/or regeneration necessary for these catalysts. Aiming at replacing those three steps by a simple one-step process, small amount of oxygen was added to WGS (the reaction called oxygen-enhanced water gas shift or OWGS) to promote the reaction kinetics and low pyrophoric ceria-supported bimetallic catalysts were employed for stable performance in this reaction. Not only CO conversion, but also H2 yield was found to increase by the O2 addition on CeO2-supported catalysts. The characteristics of OWGS, high H2 production rate at 200 to 300°C at short contact time where unreacted O2 exists, evidenced the impact of O2 addition on surface species on the catalyst. Around 1.5 of reaction order in CO for various CeO2-supported metal catalysts for OWGS compared to reaction orders in CO ranging from -0.1 to 0.6 depending on metal species for WGS shows O2 addition decreases CO coverage to free up the active sites for co-reactant (H2O) adsorption and activation. Among the monometallic and bimetallic catalysts, Pt-Cu and Pd-Cu bimetallic catalysts were superior to monometallic catalysts in OWGS. These bimetallic components were found to form alloys where noble metal is surrounded mainly by Cu to have strong interaction between noble metal and copper resulting in high OWGS activity and low pyrophoric property. The metal loadings were optimized for CeO2-supported Pd-Cu bimetallic system and 2 wt% Pd with 5 -- 10 wt% Cu were found to be the optimum for the present OWGS condition. In the kinetic study, Pd in Pd-Cu was shown to increase the active sites for H2O

  20. Carbon nitride nanosheet-supported porphyrin: a new biomimetic catalyst for highly efficient bioanalysis.

    Science.gov (United States)

    Deng, Shengyuan; Yuan, Peixin; Ji, Xubo; Shan, Dan; Zhang, Xueji

    2015-01-14

    A highly efficient biomimetic catalyst was fabricated based on ultrathin carbon nitride nanosheets (C3N4)-supported cobalt(II) proto-porphyrin IX (CoPPIX). The periodical pyridinic nitrogen units in C3N4 backbone could serve as electron donors for great affinity with Co(2+) in PPIX, which resembled the local electronic structure as vitamin B12 and heme cofactor of hemoglobin. UV-vis kinetics and electrochemistry revealed its competitive (electro)catalysis with conventional peroxidase, while X-ray photoelectron spectroscopy and theoretical calculations suggest that the rehybridization of Co 3d with N orbitals from the backside can result in significant changes in enthalpy and charge density, which greatly promoted the activity of CoPPIX. The prepared nanocatalyst was further conjugated with streptavidin via multiple amines on the edge plane of C3N4 for facile tagging. Using biotinylated molecular beacon as the capture probe, a sensitive electrochemiluminescence-based DNA assay was developed via the electroreduction of H2O2 as the coreactant after the hairpin unfolded by the target, exhibiting linearity from 1.0 fM to 0.1 nM and a detection limit of 0.37 fM. Our results demonstrate a new paradigm to rationally design inexpensive and durable biomimics for electrochemiluminescence quenching strategy, showing great promise in bioanalytical applications.

  1. Tungsten carbide modified high surface area carbon as fuel cell catalyst support

    Science.gov (United States)

    Shao, Minhua; Merzougui, Belabbes; Shoemaker, Krista; Stolar, Laura; Protsailo, Lesia; Mellinger, Zachary J.; Hsu, Irene J.; Chen, Jingguang G.

    Phase pure WC nanoparticles were synthesized on high surface area carbon black (800 m 2 g -1) by a temperature programmed reaction (TPR) method. The particle size of WC can be controlled under 30 nm with a relatively high coverage on the carbon surface. The electrochemical testing results demonstrated that the corrosion resistance of carbon black was improved by 2-fold with a surface modification by phase pure WC particles. However, the WC itself showed some dissolution under potential cycling. Based on the X-ray diffraction (XRD) and inductively coupled plasma (ICP) analysis, most of the WC on the surface was lost or transformed to oxides after 5000 potential cycles in the potential range of 0.65-1.2 V. The Pt catalyst supported on WC/C showed a slightly better ORR activity than that of Pt/C, with the Pt activity loss rate for Pt/WC/C being slightly slower compared to that of Pt/C. The performance and decay rate of Pt/WC/C were also evaluated in a fuel cell.

  2. New composite DMFC anode with PEDOT as a mixed conductor and catalyst support

    Energy Technology Data Exchange (ETDEWEB)

    Drillet, J.F.; Dittmeyer, R.; Juettner, K.; Li, L.; Mangold, K.M. [DECHEMA e.V., Karl-Winnacker-Institut, Theodor-Heuss-Allee 25, 60486 Frankfurt a. M. (Germany)

    2006-12-15

    The conducting polymer PEDOT is tested as a carbon substitute material for the DMFC anode. Electrochemical experiments are carried out in a three-electrode half-cell at room temperature. The first part of this paper focuses on the characterization of PEDOT and PEDOT-PSS as a diffusion layer material. PEDOT/C cyclic voltammograms are recorded in 1 M H{sub 2}SO{sub 4} in the range between the hydrogen evolution and polymer over-oxidation potentials. The incorporation of the PSS counter-ion into the polymer matrix leads to higher impedance values compared to PEDOT without PSS. The second part deals with the study of PEDOT as a Pt catalyst support. It is found that the partial over-oxidation of PEDOT enhances the activity of Pt for methanol oxidation. This can be explained by a change in the morphology of PEDOT that probably improves methanol diffusion within the reaction layer. The degradation of the conducting polymer is confirmed by SEM, EDX, and FTIR measurements. (Abstract Copyright [2006], Wiley Periodicals, Inc.)

  3. Catalytic Hydrotreatment of Humins in Mixtures of Formic Acid/2-Propanol with Supported Ruthenium Catalysts.

    Science.gov (United States)

    Wang, Yuehu; Agarwal, Shilpa; Kloekhorst, Arjan; Heeres, Hero Jan

    2016-05-10

    The catalytic hydrotreatment of humins, which are the solid byproducts from the conversion of C6 sugars (glucose, fructose) into 5-hydroxymethylfurfural (HMF) and levulinic acid (LA), by using supported ruthenium catalysts has been investigated. Reactions were carried out in a batch setup at elevated temperatures (400 °C) by using a hydrogen donor (formic acid (FA) in isopropanol (IPA) or hydrogen gas), with humins obtained from d-glucose. Humin conversions of up to 69 % were achieved with Ru/C and FA, whereas the performance for Ru on alumina was slightly poorer (59 % humin conversion). Humin oils were characterized by using a range of analytical techniques (GC, GC-MS, GCxGC, gel permeation chromatography) and were shown to consist of monomers, mainly alkyl phenolics (>45 % based on compounds detectable by GC) and higher oligomers. A reaction network for the reaction is proposed based on structural proposals for humins and the main reaction products. PMID:26836970

  4. Study on the distribution of active centers in novel low Ti-loading MgCl2-supported Ziegler-Natta catalyst

    Institute of Scientific and Technical Information of China (English)

    王剑峰; 王立; 赵振荣; 王文钦; 陈涛

    2004-01-01

    Novel MgCl2-supported Ziegler-Natta (Z-N) catalysts prepared using a new one-pot ball milling method can effectively control the amounts of Ti-loading in the catalysts. Complex GPC data on polypropylene synthesized by these novel catalysts were analyzed using the method of fitting the molecular weight distribution (MWD) curves with a multiple Flory-Schulz function. It was found that multiple active centers exist in these novel catalysts. Detailed study of the effects of the Ti-loadings in the catalysts on the distribution of the active centers showed that the Ti-loadings in the novel MgCl2-supported Z-N catalysts might affect the proportion of each type of active centers; and might be the main factor responsible for the effect of the Ti-loadings on the microstructure, the molecular weight and molecular weight distribution width of the resultant polymer, the catalytic activity and polymerization kinetics.

  5. Effect of Mg/Al atom ratio of support on catalytic performance of Co-Mo/MgO-Al2O3 catalyst for water gas shift reaction

    Institute of Scientific and Technical Information of China (English)

    Yixin Lian; Huifang Wang; Quanxing Zheng; Weiping Fang; Yiquan Yang

    2009-01-01

    Co-Mo-based catalysts supported on mixed oxide supports MgO-Al2O3 with different Mg/Al atom ratios for water gas shift reaction were studied by means of TPR, Raman, XPS and ESR. It was found that the octahedral Mo species in oxidized Co-Mo/MgO(x)-Al2O3 catalyst and the contents of Mo5+, Mo4+, S2- and S2-2 species in the functioning catalysts increased with increasing the Mg/Al atom ratio of the support under the studied experimental conditions. This is favorable for the formation of the active Co-Mo-S phase of the catalysts. Catalytic performance testing results showed that the catalysts Co-Mo/MgO-Al2O3 with the Mg/Al atom ratio of the support in the range of 0.475-0.525 exhibited optimal catalytic activity for the reaction.

  6. A Study of CO2 Methanation over Ni-Based Catalysts Supported by CNTs with Various Textural Characteristics

    Directory of Open Access Journals (Sweden)

    Yanyan Feng

    2015-01-01

    Full Text Available This work studied the influence of textural characteristics of CNTs on catalytic performance of Ni/CNTs for CO2 methanation. The CNTs supports were prepared by chemical vapor deposition method using Ni/MgO catalysts, and acetonitrile and ethanol were used as carbon sources, respectively. The Ni/CNTs catalysts were prepared via impregnation method and characterized by X-ray diffraction (XRD, N2 adsorption/desorption, and temperature-programmed reduction (H2-TPR techniques. The results indicated that the textural characteristics of CNTs supports significantly impacted on the catalytic performance of Ni/CNTs. The catalyst Ni/CNTs-E (CNTs using ethanol as carbon source had good reducibility, high specific surface area, and moderate defects, resulting in higher CO2 conversion and CH4 yield, followed by Ni/CNTs-C (commercial CNTs and Ni/CNTs-A (CNTs using acetonitrile as carbon source. Based on Arrhenius formula, activation energies of the catalysts were calculated and were found decreased for Ni/CNTs-A and Ni/CNTs-E.

  7. Palladium Catalysts for Fatty Acid Deoxygenation: Influence of the Support and Fatty Acid Chain Length on Decarboxylation Kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Ford, JP; Immer, JG; Lamb, HH

    2012-03-29

    Supported metal catalysts containing 5 wt% Pd on silica, alumina, and activated carbon were evaluated for liquid-phase deoxygenation of stearic (octadecanoic), lauric (dodecanoic), and capric (decanoic) acids under 5 % H-2 at 300 A degrees C and 15 atm. On-line quadrupole mass spectrometry (QMS) was used to measure CO + CO2 yield, CO2 selectivity, H-2 consumption, and initial decarboxylation rate. Post-reaction analysis of liquid products by gas chromatography was used to determine n-alkane yields. The Pd/C catalyst was highly active and selective for stearic acid (SA) decarboxylation under these conditions. In contrast, SA deoxygenation over Pd/SiO2 occurred primarily via decarbonylation and at a much slower rate. Pd/Al2O3 exhibited high initial SA decarboxylation activity but deactivated under the test conditions. Similar CO2 selectivity patterns among the catalysts were observed for deoxygenation of lauric and capric acids; however, the initial decarboxylation rates tended to be lower for these substrates. The influence of alkyl chain length on deoxygenation kinetics was investigated for a homologous series of C-10-C-18 fatty acids using the Pd/C catalyst. As fatty acid carbon number decreases, reaction time and H-2 consumption increase, and CO2 selectivity and initial decarboxylation rate decrease. The increase in initial decarboxylation rates for longer chain fatty acids is attributed to their greater propensity for adsorption on the activated carbon support.

  8. Nano-magnetite (Fe3O4) as a support for recyclable catalysts in the development of sustainable methodologies.

    Science.gov (United States)

    Gawande, Manoj B; Branco, Paula S; Varma, Rajender S

    2013-04-21

    Surface functionalization of nano-magnetic nanoparticles is a well-designed way to bridge the gap between heterogeneous and homogeneous catalysis. The introduction of magnetic nanoparticles (MNPs) in a variety of solid matrices allows the combination of well-known procedures for catalyst heterogenization with techniques for magnetic separation. Magnetite is a well-known material, also known as ferrite (Fe3O4), and can be used as a versatile support for functionalization of metals, organocatalysts, N-heterocyclic carbenes, and chiral catalysts. It is used as a support for important homogeneous catalytically active metals such as Pd, Pt, Cu, Ni, Co, Ir, etc. to obtain stable and magnetically recyclable heterogeneous catalysts. Homogeneous organocatalysts can be successfully decorated with linkers/ligands on the surface of magnetite or alternatively the organocatalysts can be directly immobilized on the surface of magnetite. The functionalized magnetically retrievable catalysts or nanocatalysts that are increasingly being used in catalysis, green chemistry and pharmaceutically significant reactions are summarized in this review.

  9. Design and Preparation of Supported Au Catalyst with Enhanced Catalytic Activities by Rationally Positioning Au Nanoparticles on Anatase.

    Science.gov (United States)

    Wang, Liang; Wang, Hong; Rice, Andrew E; Zhang, Wei; Li, Xiaokun; Chen, Mingshu; Meng, Xiangju; Lewis, James P; Xiao, Feng-Shou

    2015-06-18

    A synergistic effect between individual components is crucial for increasing the activity of metal/metal oxide catalysts. The greatest challenge is how to control the synergistic effect to obtain enhanced catalytic performance. Through density functional theory calculations of model Au/TiO2 catalysts, it is suggested that there is strong interaction between Au nanoparticles and Ti species at the edge/corner sites of anatase, which is favorable for the formation of stable oxygen vacancies. Motivated by this theoretical analysis, we have rationally prepared Au nanoparticles attached to edge/corner sites of anatase support (Au/TiO2-EC), confirmed by their HR-TEM images. As expected, this strong interaction is well characterized by Raman, UV-visible, and XPS techniques. Very interestingly, compared with conventional Au catalysts, Au/TiO2-EC exhibits superior catalytic activity in the oxidations using O2. Our approach to controlling Au nanoparticle positioning on anatase to obtain enhanced catalytic activity offers an efficient strategy for developing more novel supported metal catalysts. PMID:26266615

  10. Oxidative Dehydrogenation of n-Butane over LaV Catalysts Supported on TiO2

    Directory of Open Access Journals (Sweden)

    Le Minh Cam

    2013-01-01

    Full Text Available The catalytic performance of vanadia catalysts with 15 wt% V supported on TiO2 and (15 wt% V + 4.6 wt% La supported on TiO2 in oxidative dehydrogenation (ODH of n-butane was investigated. The catalysts were characterized by means of TPD-NH3, TPR-H2, UV-Vis, and BET. Testing of samples showed that vanadia catalysts were active for the reaction. It was found that La doping of V/TiO2 catalyst had a negative effect on the dispersion of V species and led to formation of V2O5 clusters. This resulted in a loss of activity. Although slight improvement of selectivity was observed in comparison to undoped V/TiO2 samples due to lower acidity of La-doped –V/TiO2, this could not compensate the loss of activity and finally did not lead to higher butene yields.

  11. Thermal stability and hcp-fcc allotropic transformation in supported Co metal catalysts probed near operando by ferromagnetic NMR.

    Science.gov (United States)

    Andreev, Andrey S; d'Espinose de Lacaillerie, Jean-Baptiste; Lapina, Olga B; Gerashenko, Alexander

    2015-06-14

    Despite the fact that cobalt based catalysts are used at the industrial scale for Fischer-Tropsch synthesis, it is not yet clear which cobalt metallic phase is actually at work under operando conditions and what is its state of dispersion. As it turns out, the different phases of metallic cobalt, fcc and hcp, give rise to distinct ferromagnetic nuclear magnetic resonance. Furthermore, within one Co metal particle, the occurrence of several ferromagnetic domains of limited sizes can be evidenced by the specific resonance of Co in multi-domain particles. Consequently, by ferromagnetic NMR, one can follow quantitatively the sintering and phase transitions of dispersed Co metal particles in supported catalysts under near operando conditions. The minimal size probed by ferromagnetic Co NMR is not precisely known but is considered to be in the order of 10 nm for supported Co particles at room temperature and increases to about 35 nm at 850 K. Here, in Co metal Fischer-Tropsch synthesis catalysts supported on β-SiC, the resonances of the fcc multi-domain, fcc single-domain and hcp Co were clearly distinguished. A careful rationalization of their frequency and width dependence on temperature allowed a quantitative analysis of the spectra in the temperature range of interest, thus reflecting the state of the catalysts under near operando conditions that is without the uncertainty associated with prior quenching. The allotropic transition temperature was found to start at 600-650 K, which is about 50 K below the bulk transition temperature. The phase transition was fully reversible and a significant part of the hcp phase was found to be stable up to 850 K. This anomalous behavior that was observed without quenching might prove to be crucial to understand and model active species not only in catalysts but also in battery materials. PMID:25970204

  12. Thermal stability and hcp-fcc allotropic transformation in supported Co metal catalysts probed near operando by ferromagnetic NMR.

    Science.gov (United States)

    Andreev, Andrey S; d'Espinose de Lacaillerie, Jean-Baptiste; Lapina, Olga B; Gerashenko, Alexander

    2015-06-14

    Despite the fact that cobalt based catalysts are used at the industrial scale for Fischer-Tropsch synthesis, it is not yet clear which cobalt metallic phase is actually at work under operando conditions and what is its state of dispersion. As it turns out, the different phases of metallic cobalt, fcc and hcp, give rise to distinct ferromagnetic nuclear magnetic resonance. Furthermore, within one Co metal particle, the occurrence of several ferromagnetic domains of limited sizes can be evidenced by the specific resonance of Co in multi-domain particles. Consequently, by ferromagnetic NMR, one can follow quantitatively the sintering and phase transitions of dispersed Co metal particles in supported catalysts under near operando conditions. The minimal size probed by ferromagnetic Co NMR is not precisely known but is considered to be in the order of 10 nm for supported Co particles at room temperature and increases to about 35 nm at 850 K. Here, in Co metal Fischer-Tropsch synthesis catalysts supported on β-SiC, the resonances of the fcc multi-domain, fcc single-domain and hcp Co were clearly distinguished. A careful rationalization of their frequency and width dependence on temperature allowed a quantitative analysis of the spectra in the temperature range of interest, thus reflecting the state of the catalysts under near operando conditions that is without the uncertainty associated with prior quenching. The allotropic transition temperature was found to start at 600-650 K, which is about 50 K below the bulk transition temperature. The phase transition was fully reversible and a significant part of the hcp phase was found to be stable up to 850 K. This anomalous behavior that was observed without quenching might prove to be crucial to understand and model active species not only in catalysts but also in battery materials.

  13. A Facile Preparation of Palladium Catalysts Supported on Hollow Polypyrrole Nanospheres for Ethanol Oxidation

    International Nuclear Information System (INIS)

    Graphical abstract: Ppy hollow nanospheres with uniform size have been successfully prepared and employed as the supports for Pd nanoparticles with smaller particle size and better dispersion. Electrochemical measurements demonstrate that the obtained Pd/H-ppy exhibits good electrocatalytic activity and stability for ethanol electrooxidation. - Highlights: • Ppy hollow nanospheres support provides new ways to develop catalyst materials as a result of its distorted structure and large surface area. • Ppy hollow nanospheres with uniform size have been successfully prepared through chemical oxidative polymerization of pyrrole in the presence of PS microspheres. • Pa nanoparticles have been successfully assembled on the surface of hollow ppy nanospheres. • Pd/H-ppy exhibits good electrocatalytic activity and stability for ethanol electrooxidation. - Abstract: A facile and low-cost preparation of Pd nanoparticles on the surface of hollow polypyrrole (ppy) nanospheres was introduced in this paper through solvothermal reaction. Herein, uniform polystyrene (PS) microspheres as sacrificial templates were rapidly prepared through a emulsion polymerization method, and then the hollow ppy nanospheres were obtained through chemical oxidative polymerization of pyrrole in the presence of PS microspheres. According to X-ray diffraction (XRD) and transmission electron microscopy (TEM) measurements, the novel Pd nanoparticles are well-dispersed on the surface of hollow ppy nanospheres with a relatively narrow particle size distribution. The diameters of hollow ppy nanospheres range from 240 to 280 nm, and the average shell thickness is about 15 nm. Electrochemical analysis results indicate that the as-prepared Pd nanoparticles on the surface of hollow ppy nanospheres (Pd/H-ppy) exhibit good electrocatalytic activity and stability for ethanol electrooxidation

  14. 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

    2016-01-01

    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. PMID:27196886

  15. Single-site SBA-15 supported zirconium catalysts. Synthesis, characterization and toward cyanosilylation reaction

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Wei; Yu, Bo; Zhang, Ying; Chen, Xi; Zhang, Guofang, E-mail: gfzhang@snnu.edu.cn; Gao, Ziwei, E-mail: zwgao@snnu.edu.cn

    2015-01-15

    Graphical abstract: Ligand-modified signal-site SBA-15 supported zirconium catalysts were synthesized by SOMC method and characterized by a variety of techniques. The zirconium surface complexes show high catalytic efficiency for cyanosilylation of benzaldehyde. - Highlights: • Some Zr active species have been anchored on the surface of SBA-15 by SOMC technique. • The structures of the Zr species have been characterized by a variety of techniques. • The anchored Zr species are single-sited surface complexes. • The Zr surface complexes are catalytic active for cyanosilylation of benzaldehyde. - Abstract: A successive anchoring of Zr(NMe{sub 2}){sub 4}, cyclopentadiene and a O-donor ligand, 1-hydroxyethylbenzene (PEA), 1,1′-bi-2-naphthol (Binol) or 2,3-dihydroxybutanedioic acid diethyl ester (Tartrate), on dehydroxylated SBA-15 pretreated at 500 °C for 16 h (SBA-15{sub -500}) was conducted by SOMC strategy in moderate conditions. The dehydoxylation of SBA-15 was monitored by in situ Fourier transform infrared spectroscopy (in situ FT-IR). The ligand-modified SBA-15{sub -500} supported zirconium complexes were characterized by in situ FT-IR, {sup 13}C CP MAS-NMR, X-ray photoelectron spectroscopy (XPS), inductively coupled plasma mass spectrometry (ICP-MAS) and elemental analysis in detail, verifying that the surface zirconium species are single-sited. The catalytic activity of these complexes was evaluated by cyanosilylation of benzaldehyde. The results showed that the catalytic activity is dependent strongly on the structure of surface species and the configuration of the ligands.

  16. Kinetics and deactivation of the NO reduction by CO on Pt-supported catalysts

    OpenAIRE

    Frank, Brigitta; Renken, Albert

    1999-01-01

    Reaction kinetics and catalyst deactivation during the redn. of NO with CO on a 0.5%Pt-3.4%MoO3/a-Al2O3 catalyst were investigated. The reaction shows an ignition/quenching behavior. After ignition, the reaction kinetics (formation of N2 and N2O) obey the bimol. Langmuir-Hinshelwood equations, in accordance with a dissociative mechanism. A slow catalyst deactivation is obsd. under reductive conditions (pCO >> pNO). The proposed mechanism comprises the formation of electron-withdrawing isocyan...

  17. Transition metals supported on al-pilcs as catalysts for C6H5Cl oxidation

    Directory of Open Access Journals (Sweden)

    L.C.A. Oliveira

    2003-03-01

    Full Text Available In the present work, clays pillared with aluminium and impregnated with transition metals (Fe, Co and Cr were prepared, characterised and studied as catalysts in the oxidation of chlorobenzene. The pillared clay was synthesised using a natural montmorillonite from San Juan (Argentina as the starting material and an aluminium polycation solution. The catalysts were prepared by impregnating the pillared clay and then calcinating at 500ºC. The catalysts were characterised by XRD, temperature-programmed reduction (TPR and nitrogen adsorption isotherms. The samples were tested in the deep oxidation of chlorobenzene in some cases reaching more than 90% of total conversion.

  18. Effect of samarium on methanation resistance of activated carbon supported ruthenium catalyst for ammonia synthesis

    Institute of Scientific and Technical Information of China (English)

    周春晖; 祝一锋; 刘化章

    2010-01-01

    The effects of samarium(Sm) on carbon-methanation and catalytic activity of the Ba-Ru-K/AC (active carbon) catalyst for ammonia synthesis were investigated. The addition of samarium improved significantly the activity and stability of the catalyst. The results of temperature-programmed desorption (H2-TPD) and in-situ-TPSR FTIR indicated that samarium impeded the adsorption of hydrogen on the catalyst surface, thus leading to the high catalytic activity and resistance to carbon-methanation. XRD patterns reve...

  19. Silica Supported Methanesulfonic Acid as an Efficient and Reusable Heterogeneous Catalyst for the Synthesis of Amidoalkyl Naphthols%Silica Supported Methanesulfonic Acid as an Efficient and Reusable Heterogeneous Catalyst for the Synthesis of Amidoalkyl Naphthols

    Institute of Scientific and Technical Information of China (English)

    王敏; 梁艳; 张婷婷; 高晶晶

    2011-01-01

    A green protocol for the preparation of amidoalkyl naphthols from three-component one-pot condensation of 2-naphthol, aldehydes, amides or urea in the presence of silica supported methanesulfonic acid under thermal sol- vent-free conditions has been described. The catalyst is stable, efficient, easily prepared, and reusable. The remarkable features of this methodology are short reaction time, excellent yields, simple experimental and work-up procedures.

  20. Support Effects on Thiophene Hydrodesulfurization over Co-Mo-Ni/Al2O3 and Co-Mo-Ni/TiO2-Al2O3 Catalysts

    Institute of Scientific and Technical Information of China (English)

    刘超; 周志明; 黄永利; 程振民; 袁渭康

    2014-01-01

    Hierarchically macro-/mesoporous structured Al2O3 and TiO2-Al2O3 materials were used as supports to prepare novel Co-Mo-Ni hydrodesulfurization (HDS) catalysts. A commercial Co-Mo-Ni/Al2O3 catalyst without macroporous channels was taken as a reference. The catalysts were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), energy-dispersive spectrometry (EDS), N2 adsorption-desorption, X-ray diffraction (XRD), and temperature programmed reduction (TPR). The apparent activities of the hierarchi-cally porous catalysts for thiophene HDS were superior to those of the commercial catalyst, which was mainly as-cribed to the diffusion-enhanced effect of the hierarchically bimodal pore structure. The addition of titania to alu-mina in the support helped to weaken the interaction between the active phase and the support, and as a result, the novel Co-Mo-Ni/TiO2-Al2O3 catalyst with a low titania loading (28%, by mass) in the support exhibited high HDS activities, even without presulfiding treatment. However, the catalyst with a high titania loading (61%, by mass) showed much lower activities, which was mostly caused by its low surface area and pore volume as well as the non-uniform distribution of titania and alumina. The kinetic analysis further demonstrated the support effects on HDS activities of the catalysts.