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Sample records for catalyst supports

  1. Hydrous titanium oxide-supported catalysts

    International Nuclear Information System (INIS)

    Dosch, R.G.; Stohl, F.V.; Richardson, J.T.

    1990-01-01

    Catalysts were prepared on hydrous titanium oxide (HTO) supports by ion exchange of an active metal for Na + ions incorporated in the HTO support during preparation by reaction with the parent Ti alkoxide. Strong active metal-HTO interactions as a result of the ion exchange reaction can require significantly different conditions for activation as compared to catalysts prepared by more widely used incipient wetness methods. The latter catalysts typically involve conversion or while the HTO catalysts require the alteration of electrostatic bonds between the metal and support with subsequent alteration of the support itself. In this paper, the authors discuss the activation, via sulfidation or reduction, of catalysts consisting of Co, Mo, or Ni-Mo dispersed on HTO supports by ion exchange. Correlations between the activation process and the hydrogenation, hydrodeoxygenation, and hydrodesulfurization activities of the catalysts are presented

  2. 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)

  3. 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.

  4. Carbons and carbon supported catalysts in hydroprocessing

    Energy Technology Data Exchange (ETDEWEB)

    Furimsky, Edward

    2009-07-01

    This book is a comprehensive summary of recent research in the field and covers all areas of carbons and carbon materials. The potential application of carbon supports, particularly those of carbon black (CB) and activated carbon (AC) in hydroprocessing catalysis are covered. Novel carbon materials such as carbon fibers and carbon nano tubes (CNT) are also covered, including the more recent developments in the use of fullerenes in hydroprocessing applications. Although the primary focus of this book is on carbons and carbon supported catalysts, it also identifies the difference in the effect of carbon supports compared with the oxidic supports, particularly that of the Al{sub 2}O{sub 3}. The difference in catalyst activity and stability was estimated using both model compounds and real feeds under variable conditions. The conditions applied during the preparation of carbon supported catalysts are also comprehensively covered and include various methods of pretreatment of carbon supports to enhance catalyst performance. The model compounds results consistently show higher hydrodesulfurization and hydrodeoxygenation activities of carbon supported catalysts than that of the Al{sub 2}O{sub 3} supported catalysts. Also, the deactivation of the former catalysts by coke deposition was much less evident. Chapter 6.3.1.3 is on carbon-supported catalysts: coal-derived liquids.

  5. Oxidation catalysts on alkaline earth supports

    Science.gov (United States)

    Mohajeri, Nahid

    2017-03-21

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

  6. Hydrothermal performance of catalyst supports

    Energy Technology Data Exchange (ETDEWEB)

    Elam, Jeffrey W.; Marshall, Christopher L.; Libera, Joseph A.; Dumesic, James A.; Pagan-Torres, Yomaira J.

    2018-04-10

    A high surface area catalyst with a mesoporous support structure and a thin conformal coating over the surface of the support structure. The high surface area catalyst support is adapted for carrying out a reaction in a reaction environment where the thin conformal coating protects the support structure within the reaction environment. In various embodiments, the support structure is a mesoporous silica catalytic support and the thin conformal coating comprises a layer of metal oxide resistant to the reaction environment which may be a hydrothermal environment.

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

    DEFF Research Database (Denmark)

    Wang, Ze; Zeng, Ying; Lin, Weigang

    2017-01-01

    In-situ hydrodeoxygenation of phenol with aqueous hydrogen donor over supported Ni catalyst was investigated. The supported Ni catalysts exerted very poor performance, if formic acid was used as the hydrogen donor. Catalyst modification by loading K, Na, Mg or La salt could not make the catalyst...... performance improved. If gaseous hydrogen was used as the hydrogen source the activity of Ni/Al2O3 was pretty high. CO2 was found poisonous to the catalysis, due to the competitive adoption of phenol with CO2. If formic acid was replaced by methanol, the catalyst performance improved remarkably, with major...... products of cyclohexanone and cyclohexanol. The better effect of methanol enlightened the application of the supported Ni catalyst in in-situ hydrodeoxygenation of phenol....

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

    Science.gov (United States)

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

    2015-10-20

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

  9. 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

  10. Attrition resistant Fischer-Tropsch catalyst and support

    Science.gov (United States)

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

    2004-05-25

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

  11. Titanium Dioxide as a Catalyst Support in Heterogeneous Catalysis

    Science.gov (United States)

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

    2014-01-01

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

  12. Immobilization of molecular catalysts in supported ionic liquid phases.

    Science.gov (United States)

    Van Doorslaer, Charlie; Wahlen, Joos; Mertens, Pascal; Binnemans, Koen; De Vos, Dirk

    2010-09-28

    In a supported ionic liquid phase (SILP) catalyst system, an ionic liquid (IL) film is immobilized on a high-surface area porous solid and a homogeneous catalyst is dissolved in this supported IL layer, thereby combining the attractive features of homogeneous catalysts with the benefits of heterogeneous catalysts. In this review reliable strategies for the immobilization of molecular catalysts in SILPs are surveyed. In the first part, general aspects concerning the application of SILP catalysts are presented, focusing on the type of catalyst, support, ionic liquid and reaction conditions. Secondly, organic reactions in which SILP technology is applied to improve the performance of homogeneous transition-metal catalysts are presented: hydroformylation, metathesis reactions, carbonylation, hydrogenation, hydroamination, coupling reactions and asymmetric reactions.

  13. 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.

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

    Science.gov (United States)

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

    2017-05-09

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

  15. 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.

  16. Designing Pd-based supported bimetallic catalysts for environmental applications

    OpenAIRE

    Nowicka, Ewa; Meenakshisundaram, Sankar

    2018-01-01

    Supported bimetallic nanoparticulate catalysts are an important class of heterogeneous catalysts for many reactions including selective oxidation, hydrogenation/hydrogenolysis, reforming, biomass conversion reactions, and many more. The activity, selectivity, and stability of these catalysts depend on their structural features including particle size, composition, and morphology. In this review, we present important structural features relevant to supported bimetallic catalysts focusing on Pd...

  17. Thermal and electrochemical stability of tungsten carbide catalyst supports

    Energy Technology Data Exchange (ETDEWEB)

    Chhina, H. [Ballard Power Systems, 9000 Glenlyon Parkway, Burnaby, BC (Canada); Department of Materials Engineering, University of British Columbia, Vancouver, BC (Canada); Campbell, S. [Ballard Power Systems, 9000 Glenlyon Parkway, Burnaby, BC (Canada); Kesler, O. [Department of Mechanical Engineering, University of British Columbia, Vancouver, BC (Canada)

    2007-02-10

    The thermal and electrochemical stability of tungsten carbide (WC), with and without a catalyst dispersed on it, have been investigated to evaluate the potential suitability of the material as an oxidation-resistant catalyst support. Standard techniques currently used to disperse Pt on carbon could not be used to disperse Pt on WC, so an alternative method was developed and used to disperse Pt on both commercially available WC and on carbon for comparison of stability. Electrochemical testing was performed by applying oxidation cycles between +0.6 V and +1.8 V to the support-catalyst material combinations and monitoring the activity of the supported catalyst over 100 oxidation cycles. Comparisons of activity change with cumulative oxidation cycles were made between C and WC supports with comparable loadings of catalyst by weight, solid volume, and powder volume. WC was found to be more thermally and electrochemically stable than currently used carbon support material Vulcan XC-72R. However, further optimization of the particle sizes and dispersion of Pt/WC catalyst/support materials and of comparison standards between new candidate materials and existing carbon-based supports are required. (author)

  18. 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.

  19. 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.

  20. 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

    with compositions 25Fe75Ni and 50Fe50Ni showed significantly better activity and in some cases also a higher selectivity to methane compared with the traditional monometallic Ni and Fe catalysts. A catalyst with composition 25Fe75Ni was found to be the most active in CO hydrogenation for the MgAl2O4 support at low...... metal loadings. At high metal concentrations, the maximum for the methanation activity was found for catalysts with composition 50Ni50Fe both on the MgAl2O4 and Al2O3 supports. This difference can be attributed to a higher reducibility of the constituting metals with increasing metal concentration......DFT calculations combined with a computational screening method have previously shown that bimetallic Ni-Fe alloys should be more active than the traditional Ni-based catalyst for CO methanation. That was confirmed experimentally for a number of bimetallic Ni-Fe catalysts supported on MgAl2O4. Here...

  1. Supported chromium-molybdenum and tungsten sulfide catalysts

    International Nuclear Information System (INIS)

    Chianelli, R.R.; Jacobson, A.J.; Young, A.R.

    1988-01-01

    This patent describes the process for preparing a supported hydroprocessing catalyst. The process comprising compositing a quantity of a particulate, porous catalyst support material comprising one or more refactory oxides with one or more catalyst precursor salts and heating the composite at elevated temperature of at least about 200/sup 0/C up to about 600/sup 0/, in the presence of a sulfur-bearing compound in an amount whereby sulfur in the form of the sulfur-bearing compound in an amount whereby sulfur in the form of the sulfur bearing compound is present in excess of that contained in the catalyst precursor and under oxygen-free conditions for a time sufficient to form the catalyst. The catalyst precursor salt contains a tetrathiometallate anion of Mo, W or mixture therof and a cation comprising trivalent chromium or a mixture of trivalent chromium with one or more divalent promoter metals selected from the group consisting of Fe, Ni, Co, Mn, Cu and a mixture thereof wherein the trivalent chromium and divalent promoter metals are chelated by at least one neutral, nitrogen-containing polydentate ligand, L

  2. 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.

  3. 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.

  4. 57Fe Moessbauer Studies in Mo-Fe Supported Catalysts

    International Nuclear Information System (INIS)

    Castelao-Dias, M.; Costa, B. F. O.; Quinta-Ferreira, R. M.

    2001-01-01

    Industrially, the Mo-Fe catalysts used in the selective oxidation of methanol to formaldehyde can rapidly deactivate. The use of support materials may reduce the high temperatures in the catalytic bed and/or increase thermal and mechanical resistance. However, during the preparation of these catalysts, or even during reaction conditions, the active species may react with the support material losing their catalytic activity. In this work silica, silicium carbide and titania were studied as supported catalysts by Moessbauer spectroscopy which proved to be a useful technique in the choice of supported materials

  5. 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.

  6. Polypropylene obtained through zeolite supported catalysts

    International Nuclear Information System (INIS)

    Bastos, Queli C.; Marques, Maria de Fatima V.

    2004-01-01

    Propylene polymerizations were carried out with φ 2 C(Flu)(Cp)ZrCl 2 and SiMe 2 (Ind)2ZrCl 2 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 f 2 C(Flu)(Cp)ZrCl 2 , SiO 2 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)

  7. 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(...

  8. Catalyst support effects on hydrogen spillover

    Science.gov (United States)

    Karim, Waiz; Spreafico, Clelia; Kleibert, Armin; Gobrecht, Jens; Vandevondele, Joost; Ekinci, Yasin; van Bokhoven, Jeroen A.

    2017-01-01

    Hydrogen spillover is the surface migration of activated hydrogen atoms from a metal catalyst particle, on which they are generated, onto the catalyst support. The phenomenon has been much studied and its occurrence on reducible supports such as titanium oxide is established, yet questions remain about whether hydrogen spillover can take place on nonreducible supports such as aluminium oxide. Here we use the enhanced precision of top-down nanofabrication to prepare controlled and precisely tunable model systems that allow us to quantify the efficiency and spatial extent of hydrogen spillover on both reducible and nonreducible supports. We place multiple pairs of iron oxide and platinum nanoparticles on titanium oxide and aluminium oxide supports, varying the distance between the pairs from zero to 45 nanometres with a precision of one nanometre. We then observe the extent of the reduction of the iron oxide particles by hydrogen atoms generated on the platinum using single-particle in situ X-ray absorption spectromicroscopy applied simultaneously to all particle pairs. The data, in conjunction with density functional theory calculations, reveal fast hydrogen spillover on titanium oxide that reduces remote iron oxide nanoparticles via coupled proton-electron transfer. In contrast, spillover on aluminium oxide is mediated by three-coordinated aluminium centres that also interact with water and that give rise to hydrogen mobility competing with hydrogen desorption; this results in hydrogen spillover about ten orders of magnitude slower than on titanium oxide and restricted to very short distances from the platinum particle. We anticipate that these observations will improve our understanding of hydrogen storage and catalytic reactions involving hydrogen, and that our approach to creating and probing model catalyst systems will provide opportunities for studying the origin of synergistic effects in supported catalysts that combine multiple functionalities.

  9. Interfacial charge distributions in carbon-supported palladium catalysts

    DEFF Research Database (Denmark)

    Rao, Radhika G.; Blume, Raoul; Hansen, Thomas Willum

    2017-01-01

    Controlling the charge transfer between a semiconducting catalyst carrier and the supported transition metal active phase represents an elite strategy for fine turning the electronic structure of the catalytic centers, hence their activity and selectivity. These phenomena have been theoretically...... and experimentally elucidated for oxide supports but remain poorly understood for carbons due to their complex nanoscale structure. Here, we combine advanced spectroscopy and microscopy on model Pd/C samples to decouple the electronic and surface chemistry effects on catalytic performance. Our investigations reveal...... treatments can be used to tune the interfacial charge distribution, hereby providing a strategy to rationally design carbon-supported catalysts.Control over charge transfer in carbon-supported metal nanoparticles is essential for designing new catalysts. Here, the authors show that thermal treatments...

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

    CSIR Research Space (South Africa)

    Mabena, LF

    2011-05-01

    Full Text Available ., which are among the most commonly used heterogeneous catalyst supports (Mart??nez-Me?ndez et al. 2006). Catalyst activity depends on the particle size and appropriate dis- tance between each particle. These catalysts deposited on a support... supported Pt electrodes. Appl Catal B Environ 80:286?295 Maldonado S, Morin S, Stevenson KJ (2006) Structure, composition, and chemical reactivity of carbon nanotubes by selective nitrogen doping. Carbon 44:1429?1437 Mart??nez-Me?ndez S, Henr??quez Y...

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

    DEFF Research Database (Denmark)

    Dhiman, Rajnish; Morgen, Per; Skou, E.M.

    2013-01-01

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

  12. 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%).

  13. Hydrogenation of carbon monoxide over supported palladium catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Fujimoto, K.; Hashimoto, H.; Kunugi, T.

    1978-03-01

    An alumina-supported 2% palladium catalyst had higher activity for carbon monoxide hydrogenation than a silica-supported 2% palladium catalyst, at 250/sup 0/-400/sup 0/C and 1 atm. The addition of lanthanum oxide or thorium oxide, but not of potassium oxide, to the silica-supported catalyst increased the conversion at 350/sup 0/C from 1.1% to 81.0% with a selectivity of 56.1% for methane, 1.4% for C/sub 2/ compounds, 0.1% for C/sub 3/ compounds, and 42.5% for carbon dioxide. Temperature-programed desorption of carbon monoxide in a hydrogen stream showed that of two desorption peaks observed for carbon monoxide, the one at higher temperature corresponded to the carbon monoxide species which hydrogenates to methane and that the area of this peak increased with increasing thorium content of the catalyst. Graphs, tables, and 12 references.

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

    Science.gov (United States)

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

    2008-03-01

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

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

    NARCIS (Netherlands)

    van den Berg, Roy; Parmentier, Tanja E.; Elkjaer, Christian F.; Gommes, Cedric J.; Sehested, Jens; Helveg, Stig; de Jongh, Petra E.; de Jong, Krijn P.

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

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

    Science.gov (United States)

    Serna, Pedro; Gates, Bruce C

    2014-08-19

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

  17. Sulfidation of carbon-supported iron oxide catalysts

    NARCIS (Netherlands)

    Ramselaar, W.L.T.M.; Hadders, R.H.; Gerkema, E.; Beer, de V.H.J.; Oers, van E.M.; Kraan, van der A.M.

    1989-01-01

    The sulfidation of carbon-supported iron oxide catalysts was studied by means of in-situ Mössbauer spectroscopy at temperatures down to 4.2 K. The catalysts were dried in two different ways and then sulfided in a flow of 10% H2S in H2 at temperatures between 293 and 773 K. Thiophene

  18. Constrained Geometry Organotitanium Catalysts Supported on Nanosized Silica for Ethylene (co)Polymerization.

    Science.gov (United States)

    Li, Kuo-Tseng; Wu, Ling-Huey

    2017-05-05

    Supported olefin polymerization catalysts can prevent reactor-fouling problems and produce uniform polymer particles. Constrained geometry complexes (CGCs) have less sterically hindered active sites than bis-cyclopentadienyl metallocene catalysts. In the literature, micrometer-sized silica particles were used for supporting CGC catalysts, which might have strong mass transfer limitations. This study aims to improve the activity of supported CGC catalysts by using nanometer-sized silica. Ti[(C₅Me₄)SiMe₂(N t Bu)]Cl₂, a "constrained-geometry" titanium catalyst, was supported on MAO-treated silicas (nano-sized and micro-sized) by an impregnation method. Ethylene homo-polymerization and co-polymerization with 1-octene were carried out in a temperature range of 80-120 °C using toluene as the solvent. Catalysts prepared and polymers produced were characterized. For both catalysts and for both reactions, the maximum activities occurred at 100 °C, which is significantly higher than that (60 °C) reported before for supported bis-cyclopentadienyl metallocene catalysts containing zirconium, and is lower than that (≥140 °C) used for unsupported Ti[(C₅Me₄)SiMe₂(N t Bu)]Me₂ catalyst. Activities of nano-sized catalyst were 2.6 and 1.6 times those of micro-sized catalyst for homopolymerization and copolymerization, respectively. The former produced polymers with higher crystallinity and melting point than the latter. In addition, copolymer produced with nanosized catalyst contained more 1-octene than that produced with microsized catalyst.

  19. Metal Phosphate-Supported Pt Catalysts for CO Oxidation

    Directory of Open Access Journals (Sweden)

    Xiaoshuang Qian

    2014-12-01

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

  20. Study of the catalytic activity of supported technetium catalysts

    International Nuclear Information System (INIS)

    Spitsyn, V.I.; Mikhailenko, I.E.; Pokorovskaya, O.V.

    1985-01-01

    The radioactive d metal 43 Tc 99 has catalytic properties in the synthesis of ammonia. For the purpose of reducing the quantity of the radioactive metal and of increasing the specific surface, the active component was applied to BaTiO 3 and gamma-Al 2 O 3 supports. This paper uses charcoal as a support and a table presents the catalytic activity of the samples during the synthesis of ammonia. X-ray diffractometric investigation of the catalysts was carried out with the use of Cu K /SUB alpha/ radiation. It is shown that the catalysts. The values of the specific rate constants of technetium in the catalysts. The values of the specific rate constants remain practically constant for all the catalyst samples studied, attesting to the absence of a specific metal-support interaction during the synthesis of ammonia

  1. 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.

  2. Montmorillonite Supported Titanium/Antimony Catalyst:Preparation, Characterization and Immobilization

    Institute of Scientific and Technical Information of China (English)

    CHEN Guiyong; WANG Xiaoqun; ZHAO Chuan; DU Shanyi

    2014-01-01

    Montmorillonite supported titanium (Ti-MMT) or antimony catalyst (Sb-MMT) has been a hot area of research on preparing polyethylene terephthalate/montmorillonite (PET/MMT) nanocomposites by in situ polymerization. So removal of Ti or Sb from Ti-MMT or Sb-MMT is not expected during in situ polymerization. Studies on immobilization of Ti or Sb on Ti-MMT or Sb-MMT are seldom reported. In this work, a series of montmorillonite supported catalysts of titanium (Ti-MMT) or antimony (Sb-MMT) and co-intercalated montmorillonite of titanium and antimony (Ti/Sb-MMT) were prepared by (1) the reaction of sodium bentonite suspension with intercalating solution containing titanium tetrachloride and/or antimony chloride, and (2) drying or calcinating the products at different temperature (100, 150, 240, 350 and 450℃). The physicochemical properties of these MMT supported catalysts were studied by X-ray diffraction (XRD), fourier transform infrared spectroscopy (FT-IR), inductively coupled plasma optical emission spectrometer (ICPOES), N2 adsorption/desorption isotherms, UV-visible diffuse reflectance spectroscopy(UV-vis) and transmission electron microscopy (TEM). The immobile character of Ti or Sb on MMT supported catalysts was evaluated by a two-step method in deionized water or ethylene glycol. Several results were obtained, i e, (a) during the preparation, with an increase in drying or calcinating temperature, the amount of titanium and/or antimony species remained on these MMT supported catalysts decreased, (b) the experiments about immobile character of Ti or/and Sb showed that with an increase in drying or calcinating temperature, the immobilization of Ti and/or Sb species remained on these MMT supported catalysts increased gradually, (c) Ti-MMT calcinated at 450℃had the biggest pore volume, which means Ti-MMT had the best adsorption application prospect.

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

    International Nuclear Information System (INIS)

    Escandon, Lara S.; Ordonez, Salvador; Vega, Aurelio; Diez, Fernando V.

    2008-01-01

    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 SO 2 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

  4. Dearomatization of jet fuel on irradiated platinum-supported catalyst

    International Nuclear Information System (INIS)

    Mucka, V.; Ostrihonova, A.; Kopernicky, I.; Mikula, O.

    1983-01-01

    The effect of ionizing radiation ( 60 Co #betta#-rays) on Pt-supported catalyst used for the dearomatization of jet fuel with distillation in the range 395 to 534 K has been studied. Pre-irradiation of the catalyst with doses in the range 10 2 to 5 x 10 4 Gy leads to the partial catalyst activation. Irradiation of the catalyst enhances its resistance to catalyst poisons, particularly to sulphur-compounds, and this is probably the reason for its catalytic activity being approx. 60 to 100% greater than that of un-irradiated catalyst. Optimum conditions for dearomatization on the irradiated catalyst were found and, by means of a rotary three-factorial experiment, it was shown that these lie at lower temperatures and lower pressures than those for un-irradiated catalyst. (author)

  5. 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.

  6. Glycerol valorization: dehydration to acrolein over silica-supported niobia catalysts

    NARCIS (Netherlands)

    Shiju, N.R.; Brown, D.R.; Wilson, K.; Rothenberg, G.

    2010-01-01

    The catalytic dehydration of glycerol to acrolein is investigated over silica-supported niobia catalysts in a continuous fixed-bed gas-phase reactor. Various supported niobia catalysts are prepared and characterized using surface analysis and spectroscopic methods (XRD, UV-Vis, XPS, N2 adsorption),

  7. Iron-57 and iridium-193 Moessbauer spectroscopic studies of supported iron-iridium catalysts

    International Nuclear Information System (INIS)

    Berry, F.J.; Jobson, S.

    1988-01-01

    57 Fe and 193 Ir Moessbauer spectroscopy shows that silica- and alumina-supported iron-iridium catalysts formed by calcination in air contain mixtures of small particle iron(III) oxide and iridium(IV) oxide. The iridium dioxide in both supported catalysts is reduced in hydrogen to metallic iridium. The α-Fe 2 O 3 in the silica supported materials is predominantly reduced in hydrogen to an iron-iridium alloy whilst in the alumina-supported catalyst the iron is stabilised by treatment in hydrogen as iron(II). Treatment of a hydrogen-reduced silica-supported iron catalyst in hydrogen and carbon monoxide is accompanied by the formation of iron carbides. Carbide formation is not observed when the iron-iridium catalysts are treated in similar atmospheres. The results from the bimetallic catalysts are discussed in terms of the hydrogenation of associatively adsorbed carbon monoxide and the selectivity of supported iron-iridium catalysts to methanol formation. (orig.)

  8. Graphene: a promising two-dimensional support for heterogeneous catalysts

    Directory of Open Access Journals (Sweden)

    Xiaobin eFan

    2015-01-01

    Full Text Available 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. EXAFS characterization of supported metal catalysts in chemically dynamic environments

    International Nuclear Information System (INIS)

    Robota, H.J.

    1991-01-01

    Characterization of catalysts focuses on the identification of an active site responsible for accelerating desirable chemical reactions. The identification, characterization, and selective modification of such sites is fundamental to the development of structure-function relationships. Unfortunately, this goal is far from realized in nearly all catalysts, and particularly in catalysts comprised of small supported metal particles. X-ray absorption spectroscopy (XAS) has had a dramatic effect on our understanding of supported metal particles in their resting state. However, the performance of a catalyst can not be assessed from such simple resting state measurements. Among the factors which influence catalyst performance are the exact catalyst composition, including the support and any modifiers; particle size; catalyst finishing and pretreatment conditions; pressure, composition, and temperature of the operating environment; time. Gaining an understanding of how the structure of a catalytic site can change with such an array of variables requires that we begin to develop measurement methods which are effective under chemically dynamic conditions. Ideally, it should be possible to obtain a full X-ray absorption spectrum of each element thought to have a causal relationship with observed catalyst properties. From these spectra, we can optimally extract only a relatively limited amount of information which we must then piece together with information derived from other characterization methods and intuition to arrive at a hypothetical structure of the operating catalyst. Information about crystallinity, homogeneity, and general disorder can be obtained from the Debye-Waller factor. Finally, through analogy with known compounds, the electronic structure of the active atoms can be inferred from near edge absorption features

  10. Sulfidation of alumina-supported iron and iron-molybdenum oxide catalysts

    NARCIS (Netherlands)

    Ramselaar, W.L.T.M.; Crajé, M.W.J.; Hadders, R.H.; Gerkema, E.; Beer, de V.H.J.; Kraan, van der A.M.

    1990-01-01

    The transition of alumina-supported iron and iron-molybdenum catalysts from the oxidic precursor to the sulfided catalysts was systematically studied by means of in-situ Mössbauer spectroscopy at room temperature. This enabled the adjudgement of various sulfidic phases in the sulfided catalysts. The

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

    Science.gov (United States)

    Baran, Talat

    2017-06-15

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

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

    International Nuclear Information System (INIS)

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

    2016-01-01

    Highlights: • Pd catalysts supported on TiO_2, CeO_2, Al_2O_3 and SiO_2 were prepared. • Deposition-precipitation method resulted in positively charged smaller Pd particle. • Complete debromination of tetrabromobisphenol A could be achieved on Pd/TiO_2. • Pd/TiO_2 prepared by the deposition-precipitation method was more active. - Abstract: Tetrabromobisphenol A (TBBPA) is a widely used brominated flame retardant and reductive debromination is an effective method for the abatement of TBBPA pollution. In this study, Pd catalysts supported on TiO_2, CeO_2, Al_2O_3 and SiO_2 were prepared by the impregnation (the resulting catalyst denoted as im-Pd/support), deposition-precipitation (the resulting catalyst denoted as dp-Pd/support), and photo-deposition (the resulting catalyst denoted as pd-Pd/support) methods. The catalysts were characterized by N_2 adsorption-desorption isotherm, X-ray diffraction, transmission electron microscopy, measurement of zeta potential, CO chemisorption, and X-ray photoelectron spectroscopy. The results showed that at an identical Pd loading amount (2.0 wt.%) Pd particle size in dp-Pd/TiO_2 was much smaller than those in im-Pd/TiO_2 and pd-Pd/TiO_2. Pd particle size of the dp-Pd/TiO_2 catalyst increased with Pd loading amount. Additionally, Pd particles in the dp-Pd/TiO_2 catalysts were positively charged due to the strong metal-support interaction, whereas the cationization effect was gradually attenuated with the increase of Pd loading amount. For the liquid phase catalytic hydrodebromination (HDB) of TBBPA, tri-bromobisphenol A (tri-BBPA), di-bromobisphenol A (di-BBPA), and mono-bromobisphenol A (mono-BBPA) were identified as the intermediate products, indicative of a stepwise debromination process. The catalytic HDB of TBBPA followed the Langmuir-Hinshelwood model, reflecting an adsorption enhanced catalysis mechanism. At an identical Pd loading amount, the Pd catalyst supported on TiO_2 exhibited a much higher catalytic activity

  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. {alpha}-Al{sub 2}O{sub 3} catalyst supports for synthesis gas production: influence of different alumina bonding agents on support and catalyst properties

    Energy Technology Data Exchange (ETDEWEB)

    Marturano, M. [Centro de Investigacion y Desarrollo en Procesos Cataliticos, La Plata (Argentina); Aglietti, E.F. [Centro de Tecnologia de Recursos Minerales y Ceramica (CETMIC), Gonnet (Argentina); Ferretti, O. [Centro de Investigacion y Desarrollo en Procesos Cataliticos, La Plata (Argentina)]|[Univ. Nacional de La Plata, Dept. de Ingenieria Quimica de la Facultad de Ingenieria, La Plata (Argentina)

    1997-02-01

    Aluminas are widely used as catalytic supports in chemical reactions. Reforming reactions to obtain synthesis gas requires good mechanical strength and low sintering behaviour. In this work, the influence of bentonite, aluminium phosphate and alumina gel as binder agents of a calcined {alpha}-Al{sub 2}O{sub 3} are analyzed with respect to support and catalytic properties. The {alpha}-Al{sub 2}O{sub 3} supports, calcined at 1300 C, are then impregnated with solutions of Ni and Al inorganic salts to obtain the catalysts and are finally tested in the reforming reaction of methane to synthesis gas at 500-900 C. Supports and catalysts are characterized by XRD, SEM, N{sub 2} adsorption, mechanical strength test and other techniques. Mechanical strength depends on the type and quantity of binder material used during support preparation. The influence of the support on the performance of the resulting catalyst is evidenced by means of catalytic tests. (orig.) 8 refs.

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

    International Nuclear Information System (INIS)

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

    2013-01-01

    Highlights: ► NiW catalysts supported on TiO 2 nanotubes, titania and alumina. ► The best results are obtained with NiW/TiO 2 nanotubes in hydrodesulfurization (HDS) of thiophene. ► Active phase is Ni-WO x S y . ► Electronic promotion of W by Ti. - Abstract: High surface area TiO 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 3/2 PW 12 O 40 was applied as oxide precursor of the active components. The catalyst was characterized by S 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.

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

    Science.gov (United States)

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

    2017-08-09

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

  17. Gas-phase Dehydration of Glycerol over Supported Silicotungstic Acids Catalysts

    International Nuclear Information System (INIS)

    Kim, Yong Tae; Park, Eun Duck; Jung, Kwang Deog

    2010-01-01

    The gas-phase dehydration of glycerol to acrolein was carried out over 10 wt % HSiW catalysts supported on different supports, viz. γ-Al 2 O 3 , SiO 2 -Al 2 O 3 , TiO 2 , ZrO 2 , SiO 2 , AC, CeO 2 and MgO. The same reaction was also conducted over each support without HSiW for comparison. Several characterization techniques, N 2 -physisorption, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), the temperature-programmed desorption of ammonia (NH 3 - TPD), temperature-programmed oxidation (TPO) with mass spectroscopy and CHNS analysis were employed to characterize the catalysts. The glycerol conversion generally increased with increasing amount of acid sites. Ceria showed the highest 1-hydroxyacetone selectivity at 315 .deg. C among the various metal oxides. The supported HSiW catalyst showed superior catalytic activity to that of the corresponding support. Among the supported HSiW catalysts, HSiW/ZrO 2 and HSiW/SiO 2 -Al 2 O 3 showed the highest acrolein selectivity. In the case of HSiW/ZrO 2 , the initial catalytic activity was recovered after the removal of the accumulated carbon species at 550 .deg. C in the presence of oxygen

  18. Electroreduction of oxygen on carbon-supported gold catalysts

    International Nuclear Information System (INIS)

    Erikson, Heiki; Juermann, Gea; Sarapuu, Ave; Potter, Robert J.; Tammeveski, Kaido

    2009-01-01

    The electrochemical reduction of oxygen was studied on Au/C catalysts (20 and 30 wt%) in 0.5 M H 2 SO 4 and 0.1 M KOH solutions using the rotating disk electrode (RDE) method. The thickness of the Au/C-Nafion layers was varied between 1.5 and 10 μm. The specific activity of Au was independent of catalyst loading in both solutions, indicating that the transport of reactants through the catalyst layer does not limit the process of oxygen reduction under these conditions. The mass activity of 20 wt% Au/C catalysts was higher due to smaller particle size. The number of electrons involved in the reaction and the Tafel slopes were found; the values of these parameters are similar to that of bulk polycrystalline gold and indicate that the mechanism of O 2 reduction is not affected by carbon support or the catalyst configuration.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-07-15

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

  20. Wire gauze and cordierite supported noble metal catalysts for passive autocatalytic recombiner

    International Nuclear Information System (INIS)

    Sanap, Kiran K.; Varma, S.; Waghmode, S.B.; Bharadwaj, S.R.

    2015-01-01

    Highlights: • Synthesis by electroless deposition method and chemical reduction route. • Particle size of 0.1–0.5 μm & 3.5–5 nm for Pt–Pd/Wg & Pt–Pd/Cord catalysts. • Active for H_2 and O_2 reaction with initial H_2 concentration of 1.5 to 7% in air. • Active in presence of different contaminants like CO_2, CH_4, CO & relative humidity. • Enhanced resistance of Pt–Pd/Cord catalyst towards the poisoning of CO. - Abstract: Hydrogen released in nuclear reactor containment under severe accident scenario poses a threat to containment and hence needs to be regulated by catalytic recombination. Mixed noble metal catalysts with platinum–palladium supported on stainless steel wire gauze and cordierite support have been developed for this purpose. The developed catalysts have been found to be highly efficient for removal of hydrogen concentration in the range of 1.5 to 7.0% v/v in air. Though both the catalysts exhibit similar kinetics for lower hydrogen concentration, cordierite supported catalysts exhibits better kinetic rate at higher hydrogen concentration. The performances of these catalysts in presence of various probable catalytic poison like carbon monoxide and catalytic inhibitors like moisture, carbon dioxide, and hydrocarbons provide data for use of these catalysts under the actual scenario. Compared to stainless steel wire gauze supported catalyst, the cordierite based catalyst are found to exhibit enhanced resistance towards carbon monoxide and limited temperature rise for safer application at higher hydrogen concentrations.

  1. Fuel cell testing of Pt–Ru catalysts supported on differently prepared and pretreated carbon nanotubes

    International Nuclear Information System (INIS)

    Tokarz, Wojciech; Lota, Grzegorz; Frackowiak, Elzbieta; Czerwiński, Andrzej; Piela, Piotr

    2013-01-01

    Proton-exchange membrane fuel cell (PEMFC) testing of Pt–Ru catalysts supported on differently prepared multiwall carbon nanotube (MCNT) supports was performed to elucidate the influence of the different supports on the operating characteristics of the catalysts under real direct methanol fuel cell (DMFC) anode and H 2 -PEMFC anode conditions. The MCNTs were either thin, entangled or thick, disentangled. Pretreatment of the MCNTs was also done and it was either high-temperature KOH etching or annealing (graphitization). The performance of the catalysts was compared against the performance of a commercial Pt–Ru catalyst supported on a high-surface-area carbon black. Among the different MCNT supports, the graphitized, entangled support offered the best performance in all tests, which was equal to the performance of the commercial catalyst, despite the MCNT catalyst layer was ca. 2.2 times thicker than the carbon black catalyst layer. Even for an MCNT catalyst layer, which was almost 7 times thicker than the carbon black catalyst layer, the transport limitations were not prohibitive. This confirmed the expected potential of nanotube supports for providing superior reactant transport properties of the PEMFC catalyst layers

  2. Palladium catalysts deposited on silica materials: Comparison of catalysts based on mesoporous and amorphous supports in Heck reaction

    Czech Academy of Sciences Publication Activity Database

    Demel, J.; Čejka, Jiří; Štěpnička, P.

    2010-01-01

    Roč. 329, 1-2 (2010), s. 13-20 ISSN 1381-1169 R&D Projects: GA ČR GA104/09/0561 Institutional research plan: CEZ:AV0Z40400503 Keywords : heterogeneous catalysts * immobolized catalysts * supported catalysts Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.872, year: 2010

  3. Carbon a support for sulfide catalysts

    NARCIS (Netherlands)

    Vissers, J.P.R.; Lensing, T.J.; Mercx, F.P.M.; Beer, de V.H.J.; Prins, R.

    1983-01-01

    Two types of carbon materials, carbon black composite and carbon covered alumina, were studied for-their use as support for sulfide catalysts. The following parameters were varied: type of carbon black, carbon coverage of the alumina and carbon pretreatment. Pore size distributions were determined

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

    African Journals Online (AJOL)

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

  5. Graphitized Carbon: A Promising Stable Cathode Catalyst Support Material for Long Term PEMFC Applications.

    Science.gov (United States)

    Mohanta, Paritosh Kumar; Regnet, Fabian; Jörissen, Ludwig

    2018-05-28

    Stability of cathode catalyst support material is one of the big challenges of polymer electrolyte membrane fuel cells (PEMFC) for long term applications. Traditional carbon black (CB) supports are not stable enough to prevent oxidation to CO₂ under fuel cell operating conditions. The feasibility of a graphitized carbon (GC) as a cathode catalyst support for low temperature PEMFC is investigated herein. GC and CB supported Pt electrocatalysts were prepared via an already developed polyol process. The physical characterization of the prepared catalysts was performed using transmission electron microscope (TEM), X-ray Powder Diffraction (XRD) and inductively coupled plasma optical emission spectrometry (ICP-OES) analysis, and their electrochemical characterizations were conducted via cyclic voltammetry(CV), rotating disk electrode (RDE) and potential cycling, and eventually, the catalysts were processed using membrane electrode assemblies (MEA) for single cell performance tests. Electrochemical impedance spectroscopy (EIS) and scanning electrochemical microscopy (SEM) have been used as MEA diagonostic tools. GC showed superior stability over CB in acid electrolyte under potential conditions. Single cell MEA performance of the GC-supported catalyst is comparable with the CB-supported catalyst. A correlation of MEA performance of the supported catalysts of different Brunauer⁻Emmett⁻Teller (BET) surface areas with the ionomer content was also established. GC was identified as a promising candidate for catalyst support in terms of both of the stability and the performance of fuel cell.

  6. Attrition resistant gamma-alumina catalyst support

    Science.gov (United States)

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

    2006-03-14

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

  7. Graphene supported heterogeneous catalysts for Li–O{sub 2} batteries

    Energy Technology Data Exchange (ETDEWEB)

    Alaf, M., E-mail: mirac.alaf@bilecik.edu.tr [Bilecik Seyh Edebali University, Engineering Faculty, Department of Metallurgy and Materials Engineering, Gulumbe Campus, Bilecik 11210 (Turkey); Tocoglu, U.; Kartal, M.; Akbulut, H. [Sakarya University, Engineering Faculty, Department of Metallurgy and Materials Engineering, Esentepe Campus, Sakarya 54187 (Turkey)

    2016-09-01

    Graphical abstract: - Highlights: • Free-standing and flexible electrodes were prepared for Li–air batteries. • α-MnO{sub 2} nanorods, Pt nanoparticles and graphene were used. • α-MnO{sub 2} and Pt catalyst improved OER/ORR kinetics. - Abstract: In this study production and characterization of free-standing and flexible (i) graphene, (ii) α-MnO{sub 2}/graphene, (iii) Pt/graphene (iv) α-MnO{sub 2}/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, N{sub 2} 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.

  8. THE THEORY OF DEVELOPMENT OF SUPPORTED METAL-COMPLEX CATALYSTS

    Directory of Open Access Journals (Sweden)

    T. L. Rakitskaya

    2015-06-01

    Full Text Available Some results of the investigations for the purpose of development of supported metal-complex catalysts for phosphine and carbon monoxide oxidation as well as for ozone decomposition are summarized. The activity of such catalysts has been found to depend not only on a nature of a central atom and ligands but also on a nature of supports. The theoretical model explaining mechanisms of surface complex formation taking into account the influence of physicochemical and structural-adsorption properties of the supports (SiO2, Al2O3, carbon materials, zeolites, dispersed silicas, lamellar aluminosilicates, etc. has been proposed. For quantitative description of the support effect, such a thermodynamic parameter as the adsorbed water activity assignable with the help of water vapor adsorption isotherms has been introduced. Successive stability constants of the surface metal complexes have been calculated by the kinetic method and, hence, compositions and partial catalytic activity of the latter have been determined. Taking into account the competitive adsorption of metal ions on the supports, some schemes of formation of surface bimetallic complexes have been suggested. The compositions of the supported metal-complex catalysts have been optimized to meet requirements of their use in respirators and plants for air purification from foregoing gaseous toxicants.

  9. Synthesis and characterization of platinum supported on alumina doped with cerium catalyst

    International Nuclear Information System (INIS)

    Yusof Abdullah; Abd Fatah Awang Mat; Mohd Ali Sufi; Sarimah Mahat; Razali Kassim; Nurhaslinda Abdullah.

    1996-03-01

    The synthesis and characterization of gamma-alumina doped with cerium as platinum support for the automobile exhaust catalyst are described. Platinum/alumina/ceria catalyst were prepared by impregnation of hexachloroplatinic acid and sintered at 500 degree Celsius to obtain metal dispersions of 1.0 wt%. Catalyst distribution inside the powder and the effects of the addition of cerium to alumina were analyzed by the scanning electron microscopy (SEM) and x-ray fluorescence spectroscopy (XRF). The results showed that the alumina - supported catalysts contained well dispersion of the noble metal

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

    Directory of Open Access Journals (Sweden)

    Mohamed S. Abdel Salam

    2015-03-01

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

  11. Graphitic Carbon Nitride as a Catalyst Support in Fuel Cells and Electrolyzers

    International Nuclear Information System (INIS)

    Mansor, Noramalina; Miller, Thomas S.; Dedigama, Ishanka; Jorge, Ana Belen; Jia, Jingjing; Brázdová, Veronika; Mattevi, Cecilia; Gibbs, Chris; Hodgson, David; Shearing, Paul R.; Howard, Christopher A.; Corà, Furio; Shaffer, Milo; Brett, Daniel J.L.

    2016-01-01

    Highlights: • Graphitic carbon nitride (gCN) describes many materials with different structures. • gCNs can exhibit excellent mechanical, chemical and thermal resistance. • A major obstacle for pure gCN catalyst supports is limited electronic conductivity. • Composite/Hybrid gCN structures show excellent performance as catalyst supports. • gCNs have great potential for use in fuel calls and water electrolyzers. - Abstract: Electrochemical power sources, such as polymer electrolyte membrane fuel cells (PEMFCs), require the use of precious metal catalysts which are deposited as nanoparticles onto supports in order to minimize their mass loading and therefore cost. State-of-the-art/commercial supports are based on forms of carbon black. However, carbon supports present disadvantages including corrosion in the operating fuel cell environment and loss of catalyst activity. Here we review recent work examining the potential of different varieties of graphitic carbon nitride (gCN) as catalyst supports, highlighting their likely benefits, as well as the challenges associated with their implementation. The performance of gCN and hybrid gCN-carbon materials as PEMFC electrodes is discussed, as well as their potential for use in alkaline systems and water electrolyzers. We illustrate the discussion with examples taken from our own recent studies.

  12. Hydrogenation of carbon monoxide on WO/sub 3/-Supported ruthenium catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Yoshinari, Tomohiro; Suganuma, Fujio; Sera, Chikara

    1988-01-01

    In this study, a WO/sub 3/-supported catalyst was prepared to conduct hydrogenation of CO for examining the product distribution and composition of hydrocarbons, using a gamma-alumina-supported catalyst for comparison. These catalysts were used under pressure to conduct a distributive reaction and the desorbing behavior of CO or H/sub 2/ at elevated temperature was measured to examine the influence of the type of carrier or the method of preparation on the activity and the distribution of products formed. The WO/sub 3/-supported catalyst gave a carbon chain length distribution that did not comply with the rule of Schulz-Flory, giving a composition richer in the isomers. Carbon number distribution is affected by Ru-dispersion, and the selectivity of isomers depends on the acidity of the carrier. Formed products distribution of the WO/sub 3/-supported reaction is attributable to the secondary reaction, which relates to the acidic point of the carrier, of the primary product formed on the metal. (7 figs, 4 tabs, 18 refs)

  13. 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.

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

    DEFF Research Database (Denmark)

    Larsen, Mikkel Juul

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

  15. Continuous flow hydrogenation using polysilane-supported palladium/alumina hybrid catalysts

    Directory of Open Access Journals (Sweden)

    Shū Kobayashi

    2011-05-01

    Full Text Available Continuous flow systems for hydrogenation using polysilane-supported palladium/alumina (Pd/(PSi–Al2O3 hybrid catalysts were developed. Our original Pd/(PSi–Al2O3 catalysts were used successfully in these systems and the hydrogenation of unsaturated C–C bonds and a nitro group, deprotection of a carbobenzyloxy (Cbz group, and a dehalogenation reaction proceeded smoothly. The catalyst retained high activity for at least 8 h under neat conditions.

  16. Graphitised Carbon Nanofibres as Catalyst Support for PEMFC

    DEFF Research Database (Denmark)

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

    2011-01-01

    (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...

  17. Phosphorus poisoning of molybdenum sulfide hydrodesulfurization catalysts supported on carbon and alumina

    NARCIS (Netherlands)

    Bouwens, S.M.A.M.; Vissers, J.P.R.; Beer, de V.H.J.; Prins, R.

    1988-01-01

    Phosphorus-containing Mo sulfide catalysts supported on ¿-Al2O3 and activated carbon were evaluated for their thiophene HDS activities. Phosphorus was added as phosphoric acid to the carrier material prior to the molybdenum component. The thiophene HDS activity of the carbon-supported catalysts was

  18. 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.

  19. Recent Scientific Progress on Developing Supported Ni Catalysts for Dry (CO2 Reforming of Methane

    Directory of Open Access Journals (Sweden)

    Hyun Ook Seo

    2018-03-01

    Full Text Available Two major green house gases (CO2 and CH4 can be converted into useful synthetic gas (H2 and CO during dry reforming of methane (DRM reaction, and a lot of scientific efforts has been made to develop efficient catalysts for dry reforming of methane (DRM. Noble metal-based catalysts can effectively assist DRM reaction, however they are not economically viable. Alternatively, non-noble based catalysts have been studied so far, and supported Ni catalysts have been considered as a promising candidate for DRM catalyst. Main drawback of Ni catalysts is its catalytic instability under operating conditions of DRM (>700 °C. Recently, it has been demonstrated that the appropriate choice of metal-oxide supports can address this issue since the chemical and physical of metal-oxide supports can prevent coke formation and stabilize the small Ni nanoparticles under harsh conditions of DRM operation. This mini-review covers the recent scientific findings on the development of supported Ni catalysts for DRM reaction, including the synthetic methods of supported Ni nanoparticles with high sintering resistance.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-04-15

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

  1. Heterogeneous Pd catalysts supported on silica matrices

    Czech Academy of Sciences Publication Activity Database

    Opanasenko, Maksym; Štěpnička, P.; Čejka, Jiří

    2014-01-01

    Roč. 4, č. 110 (2014), s. 65137-65162 ISSN 2046-2069 R&D Projects: GA ČR GBP106/12/G015 Institutional support: RVO:61388955 Keywords : catalysts * molecular sieves * palladium Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.840, year: 2014

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-12-01

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

  3. A phenyl-sulfonic acid anchored carbon-supported platinum catalyst for polymer electrolyte fuel cell electrodes

    International Nuclear Information System (INIS)

    Selvarani, G.; Sahu, A.K.; Choudhury, N.A.; Sridhar, P.; Pitchumani, S.; Shukla, A.K.

    2007-01-01

    A method, to anchor phenyl-sulfonic acid functional groups with the platinum catalyst supported onto a high surface-area carbon substrate, is reported. The use of the catalyst in the electrodes of a polymer electrolyte fuel cell (PEFC) helps enhancing its performance. Characterization of the catalyst by Fourier transform infra red (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and point-of-zero-charge (PZC) studies suggests that the improvement in performance of the PEFC is facilitated not only by enlarging the three-phase boundary in the catalyst layer but also by providing ionic-conduction paths as well as by imparting negative charge to platinum sites with concomitant oxidation of sulfur present in the carbon support. It is argued that the negatively charged platinum sites help repel water facilitating oxygen to access the catalyst sites. The PEFC with modified carbon-supported platinum catalyst electrodes exhibits 40% enhancement in its power density as compared to the one with unmodified carbon-supported platinum catalyst electrodes

  4. Evaluation of alumina-aluminium phosphate catalyst supports for hydrodenitrogenation of pyridine and coal-derived liquids

    Energy Technology Data Exchange (ETDEWEB)

    Menon, R.; Joo, H.S.; Guin, J.A.; Reucroft, P.J.; Kim, J.Y. [Auburn University, Auburn, AL (United States). Dept. of Chemical Engineering

    1996-05-01

    Several alumina-aluminum phosphate (AAP) catalyst supports were prepared by a coprecipitation method. Effect of variations in Al/P atomic ratios on support textural properties were examined. Finished NiMo/AAP catalysts containing nominally 3 wt% Ni and 13 wt% Mo were prepared by incipient wetness and characterized by several methods including elemental, BET, and XPS surface analysis. Initial hydrodenitrogenation (HDN) activities of the catalysts were examined in both pyridine model compound and coal liquid reactions. The AAP supports showed the opportunity to tailor the catalyst pore size by variation of the Al/P ratio. On a per unit surface areas basis, the AAP-supported catalysts had initial HDN activities comparable to those of a commercial P-promoted NiMo/Al{sub 2}O{sub 3} catalyst. Because of their unique textural properties, i.e. variable pore sizes, the AAP catalysts may offer advantages when dealing with macromolecular feedstocks where hindered diffusion may slow reaction rates. 37 refs., 8 figs., 6 tabs.

  5. 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) w...

  6. 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.

  7. 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.

  8. Synthesis of cerium oxide catalysts supported on MCM-41 molecular sieve

    International Nuclear Information System (INIS)

    Souza, E.L.S.; Barros, T.R.B.; Sousa, B.V. de

    2016-01-01

    Porous materials have been widely studied as catalysts and catalyst support. The MCM-41 structure is the one that has been most studied because of its application possibilities in chemical processes. This work aimed to obtain and characterize cerium oxide catalysts supported on MCM-41 molecular sieve. The molecular sieve was synthesized by the conventional method with the following molar composition: 1 SiO2: 0.30 CTABr: NH3 11: 144 H2O. Then, 25% w/w cerium was incorporated into the MCM-41 using the wet impregnation process and the material obtained was activated by calcination. From the XRD patterns was confirmed the structure of the molecular sieve, and were identified the cerium oxide phases in its structure. The textural catalysts characteristics were investigated by isotherms of N2 adsorption/desorption (BET method). (author)

  9. 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.)

  10. 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.

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

    Directory of Open Access Journals (Sweden)

    Giyjaz E. Bekmukhamedov

    2016-10-01

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

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

    Directory of Open Access Journals (Sweden)

    Magdalena Bonarowska

    2016-11-01

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

  13. Polyvinylpolypyrrolidone Supported Brønsted Acidic Catalyst for Esterification

    Directory of Open Access Journals (Sweden)

    Song Wang

    2016-01-01

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

  14. Hydrogen Production by Steam Reforming of Ethanol over Nickel Catalysts Supported on Sol Gel Made Alumina: Influence of Calcination Temperature on Supports.

    Science.gov (United States)

    Yaakob, Zahira; Bshish, Ahmed; Ebshish, Ali; Tasirin, Siti Masrinda; Alhasan, Fatah H

    2013-05-30

    Selecting a proper support in the catalyst system plays an important role in hydrogen production via ethanol steam reforming. In this study, sol gel made alumina supports prepared for nickel (Ni) catalysts were calcined at different temperatures. A series of (Ni/Al S.G. ) catalysts were synthesized by an impregnation procedure. The influence of varying the calcination temperature of the sol gel made supports on catalyst activity was tested in ethanol reforming reaction. The characteristics of the sol gel alumina supports and Ni catalysts were affected by the calcination temperature of the supports. The structure of the sol gel made alumina supports was transformed in the order of γ → (γ + θ) → θ-alumina as the calcination temperature of the supports increased from 600 °C to 1000 °C. Both hydrogen yield and ethanol conversion presented a volcano-shaped behavior with maximum values of 4.3 mol/mol ethanol fed and 99.5%, respectively. The optimum values were exhibited over Ni/Al S.G800 (Ni catalyst supported on sol gel made alumina calcined at 800 °C). The high performance of the Ni/Al S.G800 catalyst may be attributed to the strong interaction of Ni species and sol gel made alumina which lead to high nickel dispersion and small particle size.

  15. 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.

  16. 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.

  17. Support effects on hydrotreating activity of NiMo catalysts

    International Nuclear Information System (INIS)

    Dominguez-Crespo, M.A.; Arce-Estrada, E.M.; Torres-Huerta, A.M.; Diaz-Garcia, L.; Cortez de la Paz, M.T.

    2007-01-01

    The effect of the gamma alumina particle size on the catalytic activity of NiMoS x 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

  18. Evidence for H2/D2 isotope effects on Fischer-Tropsch synthesis over supported ruthenium catalysts

    International Nuclear Information System (INIS)

    Kellner, C.S.; Bell, A.T.

    1981-01-01

    The effects of using D 2 rather than H 2 during Fischer-Tropsch synthesis were investigated using alumina- and silica-supported Ru catalysts. For the alumina-supported catalysts, the rate of CD 4 formation was 1.4 to 1.6 times faster than the formation of CH 4 . A noticeable isotope effect was also observed for higher molecular weight products. The magnitude of the isotope effects observed using the silica-supported catalyst was much smaller than that found using the alumina-supported catalysts. The formation of olefins relative to paraffins was found to be higher when H 2 rather than D 2 was used, independent of the catalyst support. The observed isotope effects are explained in terms of a mechanism for CO hydrogenation and are shown to arise from a complex combination of the kinetic and equilibrium isotope effects associated with elementary processes occurring on the catalyst surface

  19. Carbon nanostructures as catalyst support for polymer electrolyte membrane fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Natarajan, S.K.; Hamelin, J. [Quebec Univ., Trois Rivieres, PQ (Canada). Inst. de recherche sur l' hydrogene

    2008-07-01

    This paper reported on a study that investigated potential alternatives to Vulcan XC-72 as a catalyst supports for polymer electrolyte membrane fuel cells (PEMFCs). These included carbon nanostructures (CNS) prepared by high energy ball milling of graphite and transition metal catalysts, followed by heat treatment. Among the key factors discussed were the graphitic content, high surface area, microporous structure, good electrical conductivity and the ability of the material to attach functional groups. Some graphic results supporting the usage of CNS as catalyst support for PEMFCs were presented. Upon chemical oxidation, surface functional groups such as carbonyl, carboxyl, and hydroxyl were populated on the surface of CNS. Nanosized platinum particles with particle size distribution between 3 nm and 5 nm were reduced on the functionalized sites of CNS in a colloidal medium. The paper also presented cyclic voltammograms, XPS, HRTEM and PSD results. 3 refs.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-09-11

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

  1. Dimethyl carbonate synthesis via transesterification of propylene carbonate with methanol by ceria-zinc catalysts: Role of catalyst support and reaction parameters

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Praveen; Srivastava, Vimal Chandra; Mishra, Indra Mani [Indian Institute of Technology Roorkee, Roorkee 247667, Uttarakhand (India)

    2015-09-15

    Ceria and zinc oxide catalyst were impregnated onto various oxide supports, namely Al{sub 2}O{sub 3}, TiO{sub 2} and SiO{sub 2}, individually by deposition-coprecipitation method. The synthesized catalysts (CZA, CZS and CZT having supports Al{sub 2}O{sub 3}, TiO{sub 2} and SiO{sub 2}, respectively) were characterized by X-ray diffraction (XRD), NH{sub 3}- and CO{sub 2}-temperature programmed desorption (TPD) and N2 adsorption. These catalysts were used for synthesis of dimethyl carbonate (DMC) from methanol and propylene carbonate in a batch reactor. CZS was found to have larger average grain size as compared to CZA and CZT. Composite oxides (catalysts) were found to contain individual phases of ZnO, CeO{sub 2} and some spinel forms of Zn, Ce along with their supports. CZS having highest basicity and surface area showed better catalytic activity as compared to CZA and CZT. Effect of reaction temperature and methanol/PC molar ratio on DMC yield was studied and a reaction mechanism has been discussed. Maximum DMC yield of 77% was observed with CZS catalyst at 170 .deg. C with methanol/PC molar ratio of 10.

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

    Science.gov (United States)

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

    2015-03-06

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

  3. Physicochemical investigations of carbon nanofiber supported Cu/ZrO2 catalyst

    International Nuclear Information System (INIS)

    Din, Israf Ud; Shaharun, Maizatul S.; Subbarao, Duvvuri; Naeem, A.

    2014-01-01

    Zirconia-promoted copper/carbon nanofiber catalysts (Cu‐ZrO 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 3 ). The CNF activated with 5% HNO 3 produced higher surface area which is 155 m 2 /g. The catalyst was characterized by X-ray Diffraction (XRD), Fourier Transform Infra-Red (FTIR) and N 2 adsorption-desorption. The results showed that increase of HNO 3 concentration reduced the surface area and porosity of the catalyst

  4. Secondary promoters in alumina-supported nickel-molybdenum hydroprocessing catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, J.M.

    1992-01-01

    Two secondary promoters, phosphorus and fluoride, have been investigated for their influences on the physicochemical properties of alumina-supported nickel-molybdenum hydroprocessing catalysts. Model compound reactions and infrared spectroscopy were used to probe the functionalities of the different catalysts, and the catalysts were tested in the hydroprocessing of a low-nitrogen and a high-nitrogen (quinoline-spiked) gas oil feed to assess the utility of the model compound reaction studies. Fluoride-promoted catalysts with high cumene hydrocracking activity and with comparable thiophene hydrodesulphurization (HDS) activity to Ni-Mo/Al[sub 2]O[sub 3] can be prepared by coimpregnation of the F, Ni and Mo additives. Fluoride promotes the hydrogenation (HYD) and HDS activity of Ni-Mo/Al[sub 2]O[sub 3] in the hydroprocessing (HYD) and HDS activity of Ni-Mo/Al[sub 2]O[sub 3] in the hydroprocessing of a low-nitrogen feed. Fluoride promotes the quinoline hydrodenitrogenation (HDN) activity of Ni-Mo/Al[sub 2]O[sub 3] catalysts. Impregnation of phosphorus prior to the metal additives results in catalysts which are more active in HDS. Phosphorus increases indirectly the Broensted acidity of the catalyst by increasing the activity of the MoS[sub 2]-associated acid sites. Phosphorus promotes the HDSW and HYD activities of Ni-Mo/Al[sub 2]O[sub 3] in the hydroprocessing of the low-N feed. A promotional effect of phosphorus is seen in quinoline HDN. P- and F-promoted Ni-MO/Al[sub 2]O[sub 3] catalysts are very active in quinoline HDN and maintain good activity in HDS and HYD of the high-N feed. Thiophene HDS was a good reaction for probing the activity of catalysts in the HDS of sterically-unhindered molecules, but an inaccurate probe for the HDS of hindered compounds.

  5. 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.

  6. The utilization of hydroxyapatite-supported CaO-CeO_2 catalyst for biodiesel production

    International Nuclear Information System (INIS)

    Yan, Beibei; Zhang, Ying; Chen, Guanyi; Shan, Rui; Ma, Wenchao; Liu, Changye

    2016-01-01

    Highlights: • Hydroxyapatite derived from waste animal bones was served as the support for bimetallic CaO-CeO_2 catalyst. • The 30%CaO-CeO_2/HAP-650 catalyst exhibited excellent performance on biodiesel production. • The yield of FAME was 84.4 % after eight cycles. • Minor leaching concentrations of cerium and calcium species were detected in the product. - Abstract: The study investigated the effect of a bimetallic supported catalyst in biodiesel production. Calcined waste bone derived hydroxyapatite (HAP), a solid waste from animal, was served as the support for CaO-CeO_2 catalyst. Various characterization techniques such as FT-IR, BET, SEM-EDS, CO_2-TPD and XRD analysis were used to analyse the activity of this heterogeneous catalyst. The effect of main parameters in preparation process such as calcination temperature and active component loading on catalyst performance were discussed to obtain the optimal preparation conditions. Under the optimal reaction conditions (11 wt.% dosage of 30%CaO-CeO_2/HAP-650 catalyst and 9:1 methanol to oil molar ratio at 65 °C for 3 h) the highest biodiesel yield of 91.84% was obtained. Stability test indicated that the yield (84.4%) of fatty acid methyl ester was produced after 8 re-used cycles due to the low leaching of catalyst components. The experimental results showed that biodiesel production cost might be lowered while producing relatively high yield at the present of long life-span catalyst.

  7. Hydrogen Temperature-Programmed Desorption (H2 TPD) of Supported Platinum Catalysts.

    NARCIS (Netherlands)

    Koningsberger, D.C.; Miller, J.T.; Meyers, B.L.; Modica, F.S.; Lane, G.S.; Vaarkamp, M.

    1993-01-01

    Hydrogen temperature-programmed desorption (TPD) of supported platinum catalysts, Pt/KLTL, Pt/H-LTL, Pt/K-MAZ, Pt/H-MAZ, Pt/-Al2O3, and Pt/SiO2, was performed after hydrogen reduction at 300, 450, or 650°C. For all catalysts, reversible desorption of chemisorbed hydrogen occurred at approximately

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-04-15

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

  9. Preparation of supported heterogeneous catalysts by pulse impregnation: Application to Ru[sub 3](CO)[sub 12]/2,2[prime]-bipyridine/SiO[sub 2] catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Haukka, M.; Pakkanen, T.A. (Univ. of Joensuu (Finland))

    1994-07-01

    In this paper, the authors introduce pulse impregnation, a method for preparing supported heterogeneous catalysts by successive impregnation cycles. Pulse impregnation is a method for preparing supported heterogeneous catalysts from the liquid phase. In the pulse-impregnation technique the catalyst surface is grown gradually in consecutive cycles, with each cycle consisting of separate deposition and activation steps. During the deposition step, the catalyst precursor or precursors are deposited onto the support from a suitable solvent. The actual chemically bonded catalyst phase is formed during the activation step (e.g., thermal activation). Pulse impregnation was tested in the separate deposition of 2,2[prime]-bipyridine and Ru[sub 3](CO)[sub 12] onto a silica support, and in the preparation of Ru[sub 3](CO)[sub 12]/2,2[prime]-bipyridine/SiO[sub 2] catalyst, in a column-type reactor system. Macroscopically uniform deposition was achieved with both 2,2[prime]-bipyridine and Ru[sub 3](CO)[sub 12]. Various solvent systems were used to control the amount of solute adsorbed during deposition. In the preparation of the Ru[sub 3](CO)[sub 12]/2,2[prime]-bipyridine/SiO[sub 2] catalyst, the ruthenium content increased nearly linearly with the number of preparation cycles. The effects of the preparation method on the catalyst activity was also tested in 1-hexane hydroformylation. 31 refs., 7 figs., 1 tab.

  10. Nature of the metal-support interface in supported metal catalysts: results from x-ray absorption spectroscopy

    NARCIS (Netherlands)

    Koningsberger, D.C.; Gates, B.C.

    1992-01-01

    X-ray absorption spectra characterizing the metal-support interface in supported metal complexes and supported metal catalysts are summarized and evaluated with 29 refs. Mononuclear transition metal complexes on non-reducible metal oxide supports are bonded with metal-oxygen bonds of .apprx.2.15

  11. The role of Ni in sulfided carbon-supported Ni-Mo hydrodesulfurization catalysts

    NARCIS (Netherlands)

    Bouwens, S.M.A.M.; Barthe-Zahir, N.; Beer, de V.H.J.; Prins, R.

    1991-01-01

    The thiophene hydrodesulfurization activities of Ni and Ni---Mo sulfide catalysts supported on activated carbon were measured at atmospheric pressure and the catalyst structures were studied by means of X-ray photoelectron spectroscopy, dynamic oxygen chemisorption, and chemical sulfur analysis. The

  12. Surface-reconstructed graphite nanofibers as a support for cathode catalysts of fuel cells.

    Science.gov (United States)

    Gan, Lin; Du, Hongda; Li, Baohua; Kang, Feiyu

    2011-04-07

    Graphite nanofibers (GNFs), on which surface graphite edges were reconstructed into nano-loops, were explored as a cathode catalyst support for fuel cells. The high degree of graphitization, as well as the surface-reconstructed nano-loops that possess topological defects for uniform metal deposition, resulted in an improved performance of the GNF-supported Pt catalyst.

  13. 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.

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

    International Nuclear Information System (INIS)

    Izawa, Hirozumi; Isomura, Shohei; Nakane, Ryohei.

    1979-01-01

    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)

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

    KAUST Repository

    Alotaibi, Raja; Alenazey, Feraih; Alotaibi, Faisal; Wei, Nini; Al-Fatesh, Ahmed; Fakeeha, Anis

    2015-01-01

    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.

  16. 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.

  17. Silica-supported, single-site titanium catalysts for olefin epoxidation. A molecular precursor strategy for control of catalyst structure.

    Science.gov (United States)

    Jarupatrakorn, Jonggol; Don Tilley, T

    2002-07-17

    A molecular precursor approach involving simple grafting procedures was used to produce site-isolated titanium-supported epoxidation catalysts of high activity and selectivity. The tris(tert-butoxy)siloxy titanium complexes Ti[OSi(O(t)Bu)(3)](4) (TiSi4), ((i)PrO)Ti[OSi(O(t)Bu)(3)](3) (TiSi3), and ((t)BuO)(3)TiOSi(O(t)Bu)(3) (TiSi) react with the hydroxyl groups of amorphous Aerosil, mesoporous MCM-41, and SBA-15 via loss of HO(t)Bu and/or HOSi(O(t)Bu)(3) and introduction of titanium species onto the silica surface. Powder X-ray diffraction, nitrogen adsorption/desorption, infrared, and diffuse reflectance ultraviolet spectroscopies were used to investigate the structures and chemical natures of the surface-bound titanium species. The titanium species exist mainly in isolated, tetrahedral coordination environments. Increasing the number of siloxide ligands in the molecular precursor decreases the amount of titanium that can be introduced this way, but also enhances the catalytic activity and selectivity for the epoxidation of cyclohexene with cumene hydroperoxide as oxidant. In addition, the high surface area mesoporous silicas (MCM-41 and SBA-15) are more effective than amorphous silica as supports for these catalysts. Supporting TiSi3 on the SBA-15 affords highly active cyclohexene epoxidation catalysts (0.25-1.77 wt % Ti loading) that provide turnover frequencies (TOFs) of 500-1500 h(-1) after 1 h (TOFs are reduced by about half after calcination). These results demonstrate that oxygen-rich siloxide complexes of titanium are useful as precursors to supported epoxidation catalysts.

  18. Development of supported noble metal catalyst for U(VI) to U(IV) reduction

    International Nuclear Information System (INIS)

    Tyagi, Deepak; Varma, Salil; Bhattacharyya, K.; Tripathi, A.K.; Bharadwaj, S.R.; Jain, V.K.; Sahu, Avinash; Vincent, Tessy; Jagatap, B.N.; Wattal, P.K.

    2015-01-01

    Uranium-plutonium separation is an essential step in the PUREX process employed in spent nuclear fuel reprocessing. This partitioning in the PUREX process is achieved by selective reduction of Pu(IV) to Pu(III) using uranous nitrate as reductant and hydrazine as stabilizer. Currently in our Indian reprocessing plants, the requirement of uranous nitrate is met by electrolytic reduction of uranyl nitrate. This process, however, suffers from a major drawback of incomplete reduction with a maximum conversion of ~ 60%. Catalytic reduction of U(VI) to U(IV) is being considered as one of the promising alternatives to the electro-reduction process due to fast kinetics and near total conversion. Various catalysts involving noble metals like platinum (Adams catalyst, Pt/Al 2 O 3 , Pt/SiO 2 etc.) have been reported for the reduction. Sustained activity and stability of the catalyst under harsh reaction conditions are still the issues that need to be resolved. We present here the results on zirconia supported noble metal catalyst that is developed in BARC for reduction of uranyl nitrate to uranous nitrate. Supported noble metal catalysts with varying metal loadings (0.5 - 2 wt%) were prepared via support precipitation and noble metal impregnation. The green catalysts were reduced either by chemical reduction using hydrazine hydrate or by heating in hydrogen flow or combination of both the steps. These catalysts were characterized by various techniques such as, XRD, SEM, TEM, N 2 adsorption and H 2 chemisorption. Performance of these catalysts was evaluated for U(VI) to U(IV) reduction with uranyl nitrate feed using hydrazine as reductant. The results with the most active catalyst are named as 'BARC-CAT', which was developed in our lab. (author)

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

    International Nuclear Information System (INIS)

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

    2014-01-01

    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 2 O 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

  20. 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.

  1. Hydrogen production by steam reforming of liquefied natural gas over a nickel catalyst supported on mesoporous alumina xerogel

    Science.gov (United States)

    Seo, Jeong Gil; Youn, Min Hye; Cho, Kyung Min; Park, Sunyoung; Song, In Kyu

    Mesoporous alumina xerogel (A-SG) is prepared by a sol-gel method for use as a support for a nickel catalyst. The Ni/A-SG catalyst is then prepared by an impregnation method, and is applied to hydrogen production by steam reforming of liquefied natural gas (LNG). The effect of the mesoporous alumina xerogel support on the catalytic performance of Ni/A-SG catalyst is investigated. For the purpose of comparison, a nickel catalyst supported on commercial alumina (A-C) is also prepared by an impregnation method (Ni/A-C). Both the hydroxyl-rich surface and the electron-deficient sites of the A-SG support enhance the dispersion of the nickel species on the support during the calcination step. The formation of the surface nickel aluminate phase in the Ni/A-SG catalyst remarkably increases the reducibility and stability of the catalyst. Furthermore, the high-surface area and the well-developed mesoporosity of the Ni/A-SG catalyst enhance the gasification of surface hydrocarbons that are adsorbed in the reaction. In the steam reforming of LNG, the Ni/A-SG catalyst exhibits a better catalytic performance than the Ni/A-C catalyst in terms of LNG conversion and hydrogen production. Moreover, the Ni/A-SG catalyst shows strong resistance toward catalyst deactivation.

  2. Carbon nanocages: a new support material for Pt catalyst with remarkably high durability.

    Science.gov (United States)

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

    2014-03-24

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

  3. 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

  4. MASS TRANSFER IN PORE STRUCTURES OF SUPPORTED CATALYSTS

    Directory of Open Access Journals (Sweden)

    F.R.C. Silva

    1997-09-01

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

  5. 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

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

    Science.gov (United States)

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

    2016-12-01

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

  7. Wet catalyst-support films for production of vertically aligned carbon nanotubes.

    Science.gov (United States)

    Alvarez, Noe T; Hamilton, Christopher E; Pint, Cary L; Orbaek, Alvin; Yao, Jun; Frosinini, Aldo L; Barron, Andrew R; Tour, James M; Hauge, Robert H

    2010-07-01

    A procedure for vertically aligned carbon nanotube (VA-CNT) production has been developed through liquid-phase deposition of alumoxanes (aluminum oxide hydroxides, boehmite) as a catalyst support. Through a simple spin-coating of alumoxane nanoparticles, uniform centimer-square thin film surfaces were coated and used as supports for subsequent deposition of metal catalyst. Uniform VA-CNTs are observed to grow from this film following deposition of both conventional evaporated Fe catalyst, as well as premade Fe nanoparticles drop-dried from the liquid phase. The quality and uniformity of the VA-CNTs are comparable to growth from conventional evaporated layers of Al(2)O(3). The combined use of alumoxane and Fe nanoparticles to coat surfaces represents an inexpensive and scalable approach to large-scale VA-CNT production that makes chemical vapor deposition significantly more competitive when compared to other CNT production techniques.

  8. Effect of Support Pretreatment Temperature on the Performance of an Iron Fischer–Tropsch Catalyst Supported on Silica-Stabilized Alumina

    Directory of Open Access Journals (Sweden)

    Kamyar Keyvanloo

    2018-02-01

    Full Text Available The effect of support material pretreatment temperature, prior to adding the active phase and promoters, on Fischer–Tropsch activity and selectivity was explored. Four iron catalysts were prepared on silica-stabilized alumina (AlSi supports pretreated at 700 °C, 900 °C, 1100 °C or 1200 °C. Addition of 5% silica to alumina made the AlSi material hydrothermally stable, which enabled the unusually high support pretreatment temperatures (>900 °C to be studied. High-temperature dehydroxylation of the AlSi before impregnation greatly reduces FeO·Al2O3 surface spinel formation by removing most of the support-surface hydroxyl groups leading to more effectively carbided catalyst. The activity increases more than four-fold for the support calcined at elevated temperatures (1100–1200 °C compared with traditional support calcination temperatures of <900 °C. This unique pretreatment also facilitates the formation of ε′-Fe2.2C rather than χ-Fe2.5C on the AlSi support, which shows an excellent correlation with catalyst productivity.

  9. Electrocatalytic properties of graphite nanofibers-supported platinum catalysts for direct methanol fuel cells.

    Science.gov (United States)

    Park, Soo-Jin; Park, Jeong-Min; Seo, Min-Kang

    2009-09-01

    Graphite nanofibers (GNFs) treated at various temperatures were used as carbon supports to improve the efficiency of PtRu catalysts. The electrochemical properties of the PtRu/GNFs catalysts were then investigated to evaluate their potential for application in DMFCs. The results indicated that the particle size and dispersibility of PtRu in the catalysts were changed by heat treatment, and the electrochemical activity of the catalysts was improved. Consequently, it was found that heat treatments could have an influence on the surface and structural properties of GNFs, resulting in enhancing an electrocatalytic activity of the catalysts for DMFCs.

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

    NARCIS (Netherlands)

    Bezemer, G.L.

    2006-01-01

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

  11. Carbon-supported cobalt catalyst for hydrogen generation from alkaline sodium borohydride solution

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Dongyan; Liu, Xinmin; Cao, Changqing; Guo, Qingjie [College of Chemical Engineering, Qingdao University of Science and Technology, Qingdao 266042 (China); Dai, Ping [College of Electromechanical Engineering, Qingdao University of Science and Technology, Qingdao 266061 (China)

    2008-08-01

    Low cost transition metal catalysts with high performance are attractive for the development of on-board hydrogen generation systems by catalytic hydrolysis of sodium borohydride (NaBH{sub 4}) in fuel cell fields. In this study, hydrogen production from alkaline NaBH{sub 4} via hydrolysis process over carbon-supported cobalt catalysts was studied. The catalytic activity of the supported cobalt catalyst was found to be highly dependent on the calcination temperatures. The hydrogen generation rate increases with calcination temperatures in the range of 200-400 C, but a high calcination temperature above 500 C led to markedly decreased activity. X-ray diffraction patterns reveal that the catalysts experience phase transition from amorphous Co-B to crystalline cobalt hydroxide with increase in calcination temperatures. The reaction performance is also dependent on the concentration of NaBH{sub 4}, and the hydrogen generation rate increases for lower NaBH{sub 4} concentrations and decreases after reaching a maximum at 10 wt.% of NaBH{sub 4}. (author)

  12. 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.

  13. Graphite-supported platinum catalysts: Effects of gas and aqueous phase treatments

    Energy Technology Data Exchange (ETDEWEB)

    Vleeming, J.H.; Kuster, B.F.M.; Marin, G.B. [Eindhoven Univ. of Technology (Netherlands)] [and others

    1997-03-01

    The effects on the platinum particle diameter and the available platinum surface area of a graphite-supported platinum catalyst resulting from pretreatments and from performing a selective oxidation reaction are investigated. In the gas phase considerable catalyst sintering occurs only in the presence of oxygen at 773 K due to extensive carbon burn-off, whereas in an aqueous phase platinum particle growth is limited upon oxidative treatment. A hydrogen treatment in aqueous phase at 363 K causes platinum particle growth, aggregate formation, and covering of metal sites. These phenomena become more important with increasing pH. Platinum particle growth and aggregate formation are attributed to platinum particle rather than platinum adatom mobility and is caused by the destruction of the oxygen-containing surface groups on the graphite support, which serve as anchorage sites for the platinum particles. Site covering is caused by products originating from the graphite support, which are formed as a result of the reductive treatments. When performing the aqueous phase oxidation of methyl {alpha}-D-glucopyranoside at 323 K and a pH of 9, catalyst modifications are small under oxidative conditions. Exposure of the catalyst for several hours to methyl {alpha}-D-glucopyranoside under the same conditions but in the absence of oxygen causes site covering. 50 refs., 9 figs., 1 tab.

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

    Science.gov (United States)

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

    2017-12-01

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

  15. Co, Fe and Ni catalysts supported on coke for direct coal liquefaction

    International Nuclear Information System (INIS)

    Jimenez, Jose A; Villalba, Oscar A; Rodriguez, Luis I; Hernandez, Orlando; Agamez, Yasmin Y; Dias Jose de Jesus

    2008-01-01

    Transition metal catalysts supported on coke were prepared by impregnation with a solution of complex of metal-thiourea, that is produced from salt precursors of cobalt chloride, Nickel chloride or iron sulfate and ammonium. sulphide formation on the support surface was generated by decomposition of the metal complex. The catalysts obtained were used in direct coal liquefaction of a medium volatile bituminous coal (Yerbabuena N 1) from Cundinamarca using a 250 Ml, Parr reactor at 723 K and a hydrogen-donor solvent. The catalytic results show, for all samples, both a good coal conversion and an enhancement of the yield of oils, this indicates that the proposed preparation method of catalyst is effective and that eventually the H 2 S sulphidation conventional process could be replaced

  16. 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)

  17. Process intensification by combination of activated carbon supported catalysts and alternative energy sources

    OpenAIRE

    Calvino Casilda, Vanesa; Pérez-Mayoral, E.

    2014-01-01

    [EN] Activated carbons are well known for their catalytic properties and for being used as a catalyst support in heterogeneous catalysis. Activated carbons possess most of the desired properties of a catalyst support; inertness towards unwanted reactions, stability under regeneration and reaction conditions, suitable mechanical properties, tunable surface area, porosity, and the possibility of being manufactured in different size and shape. On the other hand, the in...

  18. 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

  19. Exceptionally Stable and Efficient Solid Supported Hoveyda-Type Catalyst

    Czech Academy of Sciences Publication Activity Database

    Skowerski, K.; Pastva, J.; Czarnocki, S. J.; Janošcová, Jana

    2015-01-01

    Roč. 19, č. 7 (2015), s. 872-877 ISSN 1083-6160 Institutional support: RVO:61388955 Keywords : OLEFIN-METATHESIS CATALYSTS * RING-CLOSING METATHESIS * N-HETEROCYCLIC CARBENES Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.922, year: 2015

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-04-01

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

  1. The Stability of Supported Gold Catalysts

    NARCIS (Netherlands)

    Masoud, Nazila

    2018-01-01

    Gold has supreme cultural and financial value and, in form of nanoparticles smaller than 10 nm, is a unique catalyst for different industrially relevant reactions. Intriguing properties of the gold catalysts have spurred demand in the chemical industry for Au catalysts, the application of which

  2. 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.

  3. NMR evidence of metal-support interaction in syngas conversion catalyst Co-TiO2

    International Nuclear Information System (INIS)

    Murty, A.N.; Seamster, M.; Thorpe, A.N.; Obermyer, R.T.; Rao, V.U.S.

    1990-01-01

    To examine the relation between catalytic and magnetic properties, the zero-field NMR spectra and hysteresis loops of cobalt supported on silica, alumina, magnesia, titania, and ZSM-5 with and without the promoter thoria were investigated. Cobalt was incorporated on the support by simple physical admixture of precipitated cobalt and support, and by aqueous impregnation technique. Our studies indicate that the particle sizes are consistently lower in the presence of thoria. Of all the catalysts examined, the Co/Th/TiO 2 catalyst exhibits a high saturation magnetization value---about 20% higher than pure cobalt. In addition, the NMR spectrum of the aqueous impregnation Co/TiO 2 catalyst is distinctly different from the rest. All the NMR lines are shifted to a higher frequency by about 4 MHz. These two features---enhancement of the magnetic moment of cobalt atoms and increases in the hyperfine field at the Co nucleus---clearly indicate that there occurs strong metal-support interaction between cobalt and titania support. The higher hydrocarbon yields observed by the earlier investigators with Co/TiO 2 catalysts might be related to this phenomenon

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

    KAUST Repository

    Huang, Kuo-Wei; Hengne, Amol Mahalingappa; Bhatte, Kushal Deepak; Ould-Chikh, Samy; Saih, Youssef; Basset, Jean-Marie

    2017-01-01

    Carbon dioxide hydrogenation to oxygenates (methanol and dimethyl ether (DME)) was investigated over bifunctional supported copper catalysts promoted with gallium (Ga). Supported Cu-Ga nanocomposite catalysts were characterized by X-ray diffraction

  5. Catalytic hydrodechlorination of triclosan using a new class of anion-exchange-resin supported palladium catalysts.

    Science.gov (United States)

    Han, Bing; Liu, Wen; Li, Jingwen; Wang, Jin; Zhao, Dongye; Xu, Rui; Lin, Zhang

    2017-09-01

    We prepared a new class of anion-exchange-resin supported Pd catalysts for efficient hydrodechlorination of triclosan in water. The catalysts were prepared through an initial ion-exchange uptake of PdCl 4 2- and subsequent reduction of Pd(II) to Pd(0) nanoparticles at ambient temperature. Two standard strong-base anion exchange resins (IRA-900 and IRA-958) with different matrices (polystyrene and polyacrylic) were chosen as the supports. SEM and TEM images showed that Pd(0) nanoparticles were evenly attached on the resin surface with a mean size of 3-5 nm. The resin supported Pd catalysts (Pd@IRA-900 and Pd@IRA-958) were able to facilitate rapid and complete hydrodechlorination of triclosan. At a Pd loading of 2.0 wt.%, the observed pseudo first-order rate constant (k obs ) was 1.25 ± 0.06 and 1.6 ± 0.1 L/g/min for Pd@IRA-900 and Pd@IRA-958, respectively. The catalysts were more resistant to Cl - poisoning and natural organic matter fouling than other supported-Pd catalysts. The presence of 10 mM NaCl suppressed the k obs value by 31% and 23% for Pd@IRA-900 and Pd@IRA-958, whereas the presence of humic acid at 30 mg/L as TOC lowered the rates by 28% and 27%, respectively. The better performance of Pd@IRA-958 was attributed to the polymeric matrix properties (i.e., hydrophobicity, pore size, and surface area) as well as Pd particle size. GC/MS analyses indicated that very low concentrations of chlorinated intermediates were detected in the early stage of the hydrodechlorination process, with 2-phenoxyphenol being the main byproduct. The catalysts can be repeatedly used in multiple operations without significant bleeding. The catalysts eliminate the need for calcination in preparing conventional supported catalysts, and the resin supports conveniently facilitate control of Pd loading and material properties. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Electrochemical evaluation of Pt-Based binary catalysts on various supports for the direct methanol fuel cell

    CSIR Research Space (South Africa)

    Khotseng, L

    2016-01-01

    Full Text Available Ru/MoO(sub2) > PtSn/TiO(sub2) > PtRu/TiO(sub2). It was also observed that catalysts supported on MWCNTs were more active than those supported on metal oxides. Furthermore, catalysts supported on MWCNTs proved to be more stable than all the other supported...

  7. The challenges of treating high strength wastewaters: CWAO using MWNT supported ruthenium catalysts

    International Nuclear Information System (INIS)

    GarcIa, J.; Gomes, H.T.; Figueiredo, J.L.; Faria, J.L.; Garcia, J.; Serp, P.; Kalck, P.

    2005-01-01

    High strength wastewaters containing aromatic compounds are normally not efficiently treated by conventional methods, including the common biological treatment. In these cases a more sophisticated approach is necessary to attain the desired levels of purification. Catalytic wet air oxidation (CWAO) using carbon based catalysts is employed worldwide as effective pre-treatment of effluents with these characteristics. Carbon materials are preferred as active catalysts or support for preparing them due to their morphological and structural characteristics. In the last 10 years, due to a tremendous development in materials production and processing, carbon nano-structures are becoming more accessible and common widening their range of applications [1]. In this context, the scope of the present work is to illustrate a potential use of multi-walled carbon nano-tubes (MWNT) supported ruthenium catalysts for catalytic wet air oxidation of aniline polluted wastewaters. The metal was supported by incipient wetness and excess impregnation, starting from liquid solutions of three different Ru precursors. Impregnation was carried out on modified MWNT, namely on MWNT-COOH (HNO 3 modified) and MWNT-COONa (HNO 3 /Na 2 CO 3 modified). For the 1% weight Ru/MWNT catalysts, the order of activities decreased in the sequence Ru(COD)(COT)≥RuCl 3 ≥Ru(C 5 H 5 ) 2 . The conversion of aniline after 45 min of reaction was 100% for the catalyst prepared with Ru(COD)(COT). The influence of the Ru precursor, preparation method and the support surface modification was studied comparing the conversion of aniline obtained for the different prepared Ru/MWNT catalysts (Figure 1). MWNT as support material, provide a significant metal dispersion with very small Ru nanoparticles (Figure 2) being observed. This will induce an efficient surface contact between the aniline molecule and the active sites [2]. The excellent catalytic performances of Ru/MWNT are explained in terms of the high dispersion of

  8. A surface science study of model catalysts : II metal-support interactions in Cu/SiO2 model catalysts

    NARCIS (Netherlands)

    Oetelaar, van den L.C.A.; Partridge, A.; Toussaint, S.L.G.; Flipse, C.F.J.; Brongersma, H.H.

    1998-01-01

    The thermal stability of wet-chemically prepared Cu/SiO2 model catalysts containing nanometer-sized Cu particles on silica model supports was studied upon heating in hydrogen and ultrahigh vacuum. The surface and interface phenomena that occur are determined by the metal-support interactions.

  9. 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 interaction between perfluorosulfonic acid ionomer and supported platinum catalyst is essential. It directly influences platinum accessibility, stability of carbon support and platinum, proton conductivity and electron conductivity in an electrode. In this study, we compare the adsorption...... that the platinization step modifies the surface nature of the carbon supports in terms of specific surface area, crystallinity and especially porosity; therefore, ionomer adsorption over carbon is not always representative for the ionomer adsorption over carbon supported catalyst, though indicative. Moreover...

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

    Science.gov (United States)

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

    2017-07-15

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

  11. Deoxygenation of methyl laurate over Ni based catalysts: Influence of supports

    Science.gov (United States)

    Xia, Xiaoqiang; Chen, Hui; Bi, Yadong; Hu, Jianli

    2017-10-01

    The use of a series of nickel based catalysts supported over HZSM-5, Al2O3, C and ZrO2 in the deoxygenation of methyl laurate shows that the deoxygenation activity and deoxygenation pathway of nickel based catalysts can be affected by properties of catalysts. In the absence of H2, β-elimination of methyl laurate is the dominant reaction and a small amount of laurate acid is converted into undecane by direct decarboxylation. At the same time, the highly acidic support HZSM-5 gave higher conversion and C11 alkane selectivity. In the presence of H2, Ni/HZSM-5 catalyst showed a significantly high deoxygenation activity, producing 71% alkanes by methyl laurate conversion at 280 °C and 4MPa H2. While as on mildly acidic (Al2O3) and neutral (C) supports, a restricted hydrodeoxygenation activity was achieved but more oxygenate products were yielded. According to the analysis of intermediate product, the deoxygenation reaction of methyl laurate follows three distinct pathways: in the absence of H2, decarboxylation: C11H23COOCH3→C11H23COOH→C11H24; in the presence of H2, decarbonylation: C11H23COOCH3→C11H23COOH→C11H23CHO→C11H24; and hydrodeoxygenation: C11H23COOCH3 →C11H23COOH→C11H23CHO→C12H25OH→C12H26

  12. An iron-57 Moessbauer spectroscopic study of titania-supported iron- and iron-iridium catalysts

    International Nuclear Information System (INIS)

    Berry, F.J.; Jobson, S.

    1992-01-01

    57 Fe Moessbauer spectroscopy shows that titania-supported iron is reduced by treatment in hydrogen at significantly lower temperatures than corresponding silica- and alumina-supported catalysts. The metallic iron formed under hydrogen at 600deg C is partially converted to carbide by treatment in carbon monoxide and hydrogen. In contrast to its alumina- and silica-supported counterparts, the remainder of the titania-supported iron is unchanged by this gaseous mixture. The 57 Fe Moessbauer spectra of EXAFS show that iron and iridium in the titania-supported iron-iridium catalysts are reduced in hydrogen at even lower temperatures and, after treatment at 600deg C, are predominantly present as the iron-iridium alloy. The treatment of these reduced catalysts in carbon monoxide and hydrogen is shown by Moessbauer spectroscopy and EXAFS to induce the segregation of iron from the iron-iridium alloy and its conversion to iron oxide. (orig.)

  13. 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.

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

    KAUST Repository

    Shuai, Danmeng; Choe, Jong Kwon; Shapley, John R.; Werth, Charles J.

    2012-01-01

    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. 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.

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

    Directory of Open Access Journals (Sweden)

    Zhengyu Bai

    2015-04-01

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

  17. 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.

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

    International Nuclear Information System (INIS)

    Cui, Qian; Chao, Shujun; Bai, Zhengyu; Yan, Huiying; Wang, Kui; Yang, Lin

    2014-01-01

    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

  19. XPS analysis of supported catalysts prepared in water-in-oil microemulsion system

    International Nuclear Information System (INIS)

    Mohd Ambar Yarmo; Wong Hoi Jin; Tan Chew Khim; Anita Ramli; Shahidan Radiman

    2002-01-01

    Catalysts supported on γ-alumina prepared by water-in-oil microemulsion were studied by X-ray photoelectron spectroscopy for comparison with catalysts prepared by wet impregnation. Comparable shifts to higher binding energies indicated a metal-support interaction where metal obtained via microemulsion is very small in size and highly dispersed. The positive binding energy shifts could be explained from a net unit positive charge remaining on the cluster in the photoemission final state in addition to the metallic screening from a redistribution of states within the bands. (Author)

  20. Catalytic combustion of particulate matter Catalysts of alkaline nitrates supported on hydrous zirconium

    International Nuclear Information System (INIS)

    Galdeano, N.F.; Carrascull, A.L.; Ponzi, M.I.; Lick, I.D.; Ponzi, E.N.

    2004-01-01

    In order to explore a method to remove particulate matter, catalysts of different alkaline nitrates (Li, K and Cs) supported on hydrous zirconium were prepared by the method of incipient humidity and tested as catalysts for particulate matter combustion. The catalytic activity was determined by using the temperature programmed oxidation technique (TPO), utilizing two equipments, a thermogravimetric reactor and other of fixed bed. In the first case the particulate matter/catalyst mixture was milled carefully in a mortar (tight contact) while in the second case more realistic operative conditions were used, particulate matter/catalyst mixture was made with a spatula (loose contact). All prepared catalysts showed good activity for the particulate matter combustion. The cesium catalyst was the one that presented higher activity, decreasing the combustion temperature between 200 and 250 deg. C with respect to the combustion without catalyst. The catalyst with lithium nitrate became active at higher temperature than its melting point and the same occurred with the potassium catalyst. This did not occur for the catalyst containing cesium nitrate that melts at 407 deg. C and became active from 350 deg. C

  1. Electrooxidation of ethanol on novel multi-walled carbon nanotube supported platinum-antimony tin oxide nanoparticle catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Dao-Jun [School of Chemistry and Chemical Engineering, The Key Laboratory of Life-Organic Analysis, Qufu Normal University, Qufu, Shandong 273165 (China)

    2011-01-15

    We synthesize the new Pt based catalyst for direct ethanol fuel cells using novel multi-walled carbon nanotubes supported platinum-antimony tin oxide (Pt-ATO/MWCNT) nanoparticle as new catalyst support for the first time. The structure of Pt-ATO/MWCNT catalyst is characterized by transmission electron micrograph (TEM) and X-ray diffraction (XRD). The electrocatalytic properties of Pt-ATO/MWCNT catalyst for ethanol electrooxidation reactions are investigated by cyclic voltammetry (CV) and chronoamperometric experiments in acidic medium. The electrocatalytic activity for ethanol electrooxidation reaction shows that high carbon monoxide tolerance and good stability of Pt-ATO/MWCNT catalyst compared with Pt-SnO{sub 2}/MWCNT and commercial Pt/C are observed. These results imply that Pt-ATO/MWCNT catalyst has promising potential applications in direct alcohol fuel cells. (author)

  2. Characterization and evaluation of Pt-Ru catalyst supported on multi-walled carbon nanotubes by electrochemical impedance

    Energy Technology Data Exchange (ETDEWEB)

    Ocampo, A.L.; Miranda-Hernandez, M.; Sebastian, P.J. [Centro de Investigacion en Energia-UNAM, Temixco, 62580 Morelos (Mexico); Morgado, J.; Montoya, J.A. [IMP, Eje Central Lazaro Cardenas 152, 07730 D.F. Mexico (Mexico)

    2006-10-06

    In this work the authors present the results of a systematic characterization and evaluation of the carbon nanotube supported Pt-Ru (Pt-Ru/CNT) for its use as methanol oxidation catalyst. Its activity was compared with that of Pt and Pt-Ru catalysts supported on Vulcan and synthesized from carbonyl precursors, and another commercial Pt-Ru catalyst. The cyclic voltammetry, CO stripping and electrochemical impedance techniques were employed to determine the electrocatalytic activity of the catalysts. The electrochemical studies were performed in 0.5M H{sub 2}SO{sub 4} containing different concentrations of methanol (0.05-1M). The results showed a noticeable influence of the catalyst support (CNT) on the performance of the catalyst for CO oxidation. The electrochemical impedance studies allowed us to separate the different steps in the methanol oxidation reaction and to control these steps or reactions by varying the applied potential and the methanol concentration. At low methanol concentration and potentials the de-hydrogenation of methanol predominated. But, at high potential and methanol concentrations, the CO oxidation predominated. These results allowed us to clearly describe at what potential and concentration ranges the bi-functional effect of Ru becomes evident. Our results indicated that the CO oxidation occurs both on Pt and Ru. Compared to other catalysts, Pt-Ru supported on carbon nanotubes showed superior catalytic activity for CO and methanol oxidation. (author)

  3. Promising SiC support for Pd catalyst in selective hydrogenation of acetylene to ethylene

    Science.gov (United States)

    Guo, Zhanglong; Liu, Yuefeng; Liu, Yan; Chu, Wei

    2018-06-01

    In this study, SiC supported Pd nanoparticles were found to be an efficient catalyst in acetylene selective hydrogenation reaction. The ethylene selectivity can be about 20% higher than that on Pd/TiO2 catalyst at the same acetylene conversion at 90%. Moreover, Pd/SiC catalyst showed a stable catalytic life at 65 °C with 80% ethylene selectivity. With the detailed characterization using temperature-programmed reduction (H2-TPR), powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), N2 adsorption/desorption analysis, CO-chemisorption and thermo-gravimetric analysis (TGA), it was found that SiC owns a lower surface area (22.9 m2/g) and a broad distribution of meso-/macro-porosity (from 5 to 65 nm), which enhanced the mass transfer during the chemical process at high reaction rate and decreased the residence time of ethylene on catalyst surface. Importantly, SiC support has the high thermal conductivity, which favored the rapid temperature homogenization through the catalyst bed and inhabited the over-hydrogenation of acetylene. The surface electronic density of Pd on Pd/SiC catalyst was higher than that on Pd/TiO2, which could promote desorption of ethylene from surface of the catalyst. TGA results confirmed a much less coke deposition on Pd/SiC catalyst.

  4. Characterization and Catalytic Activity of Montmorillonite K10-Supported Cobalt Catalysts

    International Nuclear Information System (INIS)

    Gobara, H.M.; Ghattas, M.S.; Henien, S.A.

    2010-01-01

    Montmorillonite K10-supported cobalt catalysts were prepared by wet impregnation method. The samples were analyzed by XRD, TPR, FTTR and BET characterization techniques. [Three phases of cobalt species were identified namely, cobalt oxide (Co 3 O 4 ), cobalt silicate (Co 2 S 1 O 4 ) and cobalt aluminate (CoAl 2 O 4 ). These species were most probably existing within the inter lamellar spaces of the meso porous montmorillonite K10 support]. The two bands observed at 1385 and 760 cm 1 were characteristic of metal species rather than the support, being mostly of Co - O bond vibration. The hysteresis loop, pore size distribution, pore volume and BET surface area were greatly affected by cobalt loading. The catalyst containing 18 wt% cobalt was the most selective sample for ethylene production from ethanol dehydration.

  5. 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.

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

    NARCIS (Netherlands)

    Wolters, M.

    2010-01-01

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

  7. Understanding the Performance and Stability of Supported Ni-Co-Based Catalysts in Phenol HDO

    Directory of Open Access Journals (Sweden)

    Thuan M. Huynh

    2016-11-01

    Full Text Available Performances of bimetallic catalysts (Ni-Co supported on different acidic carriers (HZSM-5, HBeta, HY, ZrO2 and corresponding monometallic Ni catalysts in aqueous phase hydrodeoxygenation of phenol were compared in batch and continuous flow modes. The results revealed that the support acidity plays an important role in deoxygenation as it mainly controls the oxygen-removing steps in the reaction network. At the same time, sufficient hydrothermal stability of a solid catalyst is essential. Batch experiments revealed 10Ni10Co/HZSM-5 to be the best-performing catalyst in terms of conversion and cyclohexane yield. Complementary continuous runs provided more insights into the relationship between catalyst structure, efficiency and stability. After 24 h on-stream, the catalyst still reveals 100% conversion and a slight loss (from 100% to 90% in liquid hydrocarbon selectivity. The observed alloy of Co with Ni increased dispersion and stability of Ni-active sites, and combination with HZSM-5 resulted in a well-balanced ratio of metal and acid sites which promoted all necessary steps in preferred pathways. This was proved by studies of fresh and spent catalysts using various characterization techniques (N2 physisorption, X-ray diffraction (XRD, X-ray photoelectron spectroscopy (XPS, transmission electron microscopy (TEM and infrared spectroscopy of adsorbed pyridine (pyr-IR.

  8. Polymer supported organic catalysts for O2 reduction in Li-O2 batteries

    International Nuclear Information System (INIS)

    Weng, Wei; Barile, Christopher J.; Du, Peng; Abouimrane, Ali; Assary, Rajeev S.; Gewirth, Andrew A.; Curtiss, Larry A.; Amine, Khalil

    2014-01-01

    Graphical abstract: - Abstract: A novel organic catalyst has been synthesized that contains an anthraquinone moiety supported on a polymer backbone. This oxygen reduction catalyst was successfully incorporated in the cathode of Li-O 2 batteries. The addition of the anthraquinone-based catalyst improved the cycleability of the Li-O 2 battery when cycled in a tetraethylene glycol dimethyl ether electrolyte. Computational studies coupled with a wide range of analytical techniques including differential electrochemical mass spectrometry, cyclic voltammetry, electrochemical impedence spectroscopy, and X-ray diffraction were used to interrogate the Li-O 2 battery with and without the organic catalyst present. This study suggests that organic catalysts may serve as light and inexpensive alternatives to the precious metals frequently used in Li-O 2 batteries

  9. The challenges of treating high strength wastewaters: CWAO using MWNT supported ruthenium catalysts

    Energy Technology Data Exchange (ETDEWEB)

    GarcIa, J.; Gomes, H.T.; Figueiredo, J.L.; Faria, J.L. [Porto Univ., Lab. de Catalise e Materiais, Dept. de Engenharia Quimica, Faculdade de Engenharia (Portugal); Garcia, J. [Madrid Univ. Complutense, Grupo de Catalisis y Operaciones de Separacion, Dept. de Ingenieria Quimica, Facultad de Ciencias (Spain); Serp, P.; Kalck, P. [Ecole Nationale Superieure des Ingenieurs en Arts Chimiques et Technologiques, Lab. de Catalyse, Chimie Fine et Polymeres, 31 - Toulouse (France)

    2005-07-01

    High strength wastewaters containing aromatic compounds are normally not efficiently treated by conventional methods, including the common biological treatment. In these cases a more sophisticated approach is necessary to attain the desired levels of purification. Catalytic wet air oxidation (CWAO) using carbon based catalysts is employed worldwide as effective pre-treatment of effluents with these characteristics. Carbon materials are preferred as active catalysts or support for preparing them due to their morphological and structural characteristics. In the last 10 years, due to a tremendous development in materials production and processing, carbon nano-structures are becoming more accessible and common widening their range of applications [1]. In this context, the scope of the present work is to illustrate a potential use of multi-walled carbon nano-tubes (MWNT) supported ruthenium catalysts for catalytic wet air oxidation of aniline polluted wastewaters. The metal was supported by incipient wetness and excess impregnation, starting from liquid solutions of three different Ru precursors. Impregnation was carried out on modified MWNT, namely on MWNT-COOH (HNO{sub 3} modified) and MWNT-COONa (HNO{sub 3}/Na{sub 2}CO{sub 3} modified). For the 1% weight Ru/MWNT catalysts, the order of activities decreased in the sequence Ru(COD)(COT){>=}RuCl{sub 3}{>=}Ru(C{sub 5}H{sub 5}){sub 2}. The conversion of aniline after 45 min of reaction was 100% for the catalyst prepared with Ru(COD)(COT). The influence of the Ru precursor, preparation method and the support surface modification was studied comparing the conversion of aniline obtained for the different prepared Ru/MWNT catalysts (Figure 1). MWNT as support material, provide a significant metal dispersion with very small Ru nanoparticles (Figure 2) being observed. This will induce an efficient surface contact between the aniline molecule and the active sites [2]. The excellent catalytic performances of Ru/MWNT are explained

  10. 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

  11. An efficient hybrid, nanostructured, epoxidation catalyst: titanium silsesquioxane-polystyrene copolymer supported on SBA-15.

    Science.gov (United States)

    Zhang, Lei; Abbenhuis, Hendrikus C L; Gerritsen, Gijsbert; Bhriain, Nollaig Ní; Magusin, Pieter C M M; Mezari, Brahim; Han, Wei; van Santen, Rutger A; Yang, Qihua; Li, Can

    2007-01-01

    A novel interfacial hybrid epoxidation catalyst was designed with a new immobilization method for homogeneous catalysts by coating an inorganic support with an organic polymer film containing active sites. The titanium silsesquioxane (TiPOSS) complex, which contains a single-site titanium active center, was immobilized successfully by in-situ copolymerization on a mesoporous SBA-15-supported polystyrene polymer. The resulting hybrid materials exhibit attractive textural properties (highly ordered mesostructure, large specific surface area (>380 m2 g-1) and pore volume (>or==0.46 cm3 g-1)), and high activity in the epoxidation of alkenes. In the epoxidation of cyclooctene with tert-butyl hydrogen peroxide (TBHP), the hybrid catalysts have rate constants comparable with that of their homogeneous counterpart, and can be recycled at least seven times. They can also catalyze the epoxidation of cyclooctene with aqueous H2O2 as the oxidant. In two-phase reaction media, the catalysts show much higher activity than their homogeneous counterpart due to the hydrophobic environment around the active centers. They behave as interfacial catalysts due to their multifunctionality, that is, the hydrophobicity of polystyrene and the polyhedral oligomeric silsesquioxanes (POSS), and the hydrophilicity of the silica and the mesoporous structure. Combination of the immobilization of homogeneous catalysts on two conventional supports, inorganic solid and organic polymer, is demonstrated to achieve novel heterogeneous catalytic ensembles with the merits of attractive textural properties, tunable surface properties, and optimized environments around the active sites.

  12. 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.

  13. Final Report - Advanced Cathode Catalysts and Supports for PEM Fuel Cells

    Energy Technology Data Exchange (ETDEWEB)

    Debe, Mark

    2012-09-28

    The principal objectives of the program were development of a durable, low cost, high performance cathode electrode (catalyst and support), that is fully integrated into a fuel cell membrane electrode assembly with gas diffusion media, fabricated by high volume capable processes, and is able to meet or exceed the 2015 DOE targets. Work completed in this contract was an extension of the developments under three preceding cooperative agreements/grants Nos. DE-FC-02-97EE50473, DE-FC-99EE50582 and DE-FC36- 02AL67621 which investigated catalyzed membrane electrode assemblies for PEM fuel cells based on a fundamentally new, nanostructured thin film catalyst and support system, and demonstrated the feasibility for high volume manufacturability.

  14. Preparation of ethylene/1-hexene copolymers from ethylene using a fully silica-supported tandem catalyst system

    NARCIS (Netherlands)

    Karbach, Fabian F.; Macko, Tibor; Duchateau, Robbert

    2016-01-01

    A silica-supported tandem catalyst system, capable of producing ethylene/1-hexene copolymers from ethylene being the single monomer, has been investigated. As tandem couple a phenoxyimine titanium catalyst for ethylene trimerization was combined with a metallocene catalyst for α-olefin

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-07-01

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

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

    CSIR Research Space (South Africa)

    Ejikeme, PM

    2016-07-01

    Full Text Available The operating life of a fuel cell is expected to be thousands of hours. One of the critical components of the fuel cell that will allow for such long-life cycle is the catalyst-support material. The support material is expected, amongst others...

  17. Functionalized Natural Carbon-Supported Nanoparticles as Excellent Catalysts for Hydrocarbon Production.

    Science.gov (United States)

    Sun, Jian; Guo, Lisheng; Ma, Qingxiang; Gao, Xinhua; Yamane, Noriyuki; Xu, Hengyong; Tsubaki, Noritatsu

    2017-02-01

    We report a one-pot and eco-friendly synthesis of carbon-supported cobalt nanoparticles, achieved by carbonization of waste biomass (rice bran) with a cobalt source. The functionalized biomass provides carbon microspheres as excellent catalyst support, forming a unique interface between hydrophobic and hydrophilic groups. The latter, involving hydroxyl and amino groups, can catch much more active cobalt nanoparticles on surface for Fischer-Tropsch synthesis than chemical carbon. The loading amount of cobalt on the final catalyst is much higher than that prepared with a chemical carbon source, such as glucose. The proposed concept of using a functionalized natural carbon source shows great potential compared with conventional carbon sources, and will be meaningful for other fields concerning carbon support, such as heterogeneous catalysis or electrochemical fields. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Effect of support on the activity of MoVCeZr catalyst for propane ammoxidation reaction

    International Nuclear Information System (INIS)

    Anita Ramli; Farinaa Md Jamil; Ishak Ahmad

    2010-01-01

    Mixed metal oxide catalysts based on Mo-V have been known as the most active and selective in the ammoxidation of propane to ACN. A series of MoVCeZr (5 % wt/ wt) supported with MOR, TiO 2 and MgO have been prepared by incipient wetness impregnation method for propane ammoxidation reaction to ACN. The catalyst was calcined in a two step calcination process in static air between 350 - 600 degree Celsius for 10 hour. The surface area and pore size of these catalysts were measured using physical adsorption of nitrogen following Brunauer, Emmet and Teller (BET) equation. The textural and morphological of these catalysts were determined using Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD). The activities of all catalysts were tested using a fixed-bed reactor with online gas chromatography (GC) at 420 degree Celsius and atmospheric pressure in the presence of 0.5 ml catalyst with composition consisting of 5.8:7:17.4 (propane: ammonia: air) and helium as carrier to give a total flow of 120 ml. Result shows that MoVCeZr support gives a better conversion due to the surface area and pore size characteristic of the catalyst. (author)

  19. 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)

    Wojcieszak, R.

    2006-06-01

    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-Al 2 O 3 , amorphous or crystallized SiO 2 , Nb 2 O 5 , CeO 2 and carbon). Prepared catalysts were characterized by different methods (XRD, XPS, low temperature adsorption and desorption of N 2 , FTIR and FTIR-Pyridine, TEM, STEM, EDS, H 2 -TPR, H 2 -adsorption, H 2 -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/SiO 2 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)

  20. Engineering catalytic activity via ion beam bombardment of catalyst supports for vertically aligned carbon nanotube growth

    Science.gov (United States)

    Islam, A. E.; Nikolaev, P.; Amama, P. B.; Zakharov, D.; Sargent, G.; Saber, S.; Huffman, D.; Erford, M.; Semiatin, S. L.; Stach, E. A.; Maruyama, B.

    2015-09-01

    Carbon nanotube growth depends on the catalytic activity of metal nanoparticles on alumina or silica supports. The control on catalytic activity is generally achieved by variations in water concentration, carbon feed, and sample placement on a few types of alumina or silica catalyst supports obtained via thin film deposition. We have recently expanded the choice of catalyst supports by engineering inactive substrates like c-cut sapphire via ion beam bombardment. The deterministic control on the structure and chemistry of catalyst supports obtained by tuning the degree of beam-induced damage have enabled better regulation of the activity of Fe catalysts only in the ion beam bombarded areas and hence enabled controllable super growth of carbon nanotubes. A wide range of surface characterization techniques were used to monitor the catalytically active surface engineered via ion beam bombardment. The proposed method offers a versatile way to control carbon nanotube growth in patterned areas and also enhances the current understanding of the growth process. With the right choice of water concentration, carbon feed and sample placement, engineered catalyst supports may extend the carbon nanotube growth yield to a level that is even higher than the ones reported here, and thus offers promising applications of carbon nanotubes in electronics, heat exchanger, and energy storage.

  1. Effect of Au Precursor and Support on the Catalytic Activity of the Nano-Au-Catalysts for Propane Complete Oxidation

    Directory of Open Access Journals (Sweden)

    Arshid M. Ali

    2015-01-01

    Full Text Available Catalytic activity of nano-Au-catalyst(s for the complete propane oxidation was investigated. The results showed that the nature of both Au precursor and support strongly influences catalytic activity of the Au-catalyst(s for the propane oxidation. Oxidation state, size, and dispersion of Au nanoparticles in the Au-catalysts, surface area, crystallinity, phase structure, and redox property of the support are the key aspects for the complete propane oxidation. Among the studied Au-catalysts, the AuHAuCl4-Ce catalyst is found to be the most active catalyst.

  2. An efficient hybrid, nanostructured, epoxidation catalyst: titanium silsesquioxane-polystyrene copolymer supported on SBA-15

    NARCIS (Netherlands)

    Santen, van R.A.; Zhang, Lei; Abbenhuis, H.C.L.; Gerritsen, G.; Ní Bhriain, N.M.; Magusin, P.C.M.M.; Mezari, B.; Han, W.; Yang, Q.; Li, Can

    2007-01-01

    A novel interfacial hybrid epoxidation catalyst was designed with a new immobilization method for homogeneous catalysts by coating an inorganic support with an organic polymer film containing active sites. The titanium silsesquioxane (TiPOSS) complex, which contains a single-site titanium active

  3. Porous graphene supported Pt catalysts for proton exchange membrane fuel cells

    International Nuclear Information System (INIS)

    Cheng, Kun; He, Daping; Peng, Tao; Lv, Haifeng; Pan, Mu; Mu, Shichun

    2014-01-01

    Graphene nanosheet (GNS) has a remarkably high ratio of surface area to thickness and intense inter-sheet aggregation, which heavily resist mass diffusion in vertical orientation. Here, we establish a fast-speed mass diffusion passage by creating pores in GNS, and the corresponding Pt catalyst (Pt/rPGO) displays 15.5 times mass diffusion rate than that of the pristine GNS supported Pt catalyst (Pt/rGO). Thus, the Pt/rPGO catalyst exhibits 1.5 times increase in Pt mass activity toward oxygen reduction reaction compared with the Pt/rGO. Significantly, after H 2 thermal treatment, the mass activity of the Pt/rPGO further increases to 1.9 times that of the Pt/rGO, and its electrochemical stability is also greatly improved

  4. An oxidation-resistant indium tin oxide catalyst support for proton exchange membrane fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Chhina, H.; Campbell, S. [Ballard Power Systems Inc., 9000 Glenlyon Parkway, Burnaby, BC V5J 5J8 (Canada); Kesler, O. [Department of Mechanical Engineering, University of British Columbia, Vancouver, BC, V6T 1Z4 (Canada)

    2006-10-27

    The oxidation of carbon catalyst supports causes degradation in catalyst performance in proton exchange membrane fuel cells (PEMFCs). Indium tin oxide (ITO) is considered as a candidate for an alternative catalyst support. The electrochemical stability of ITO was studied by use of a rotating disk electrode (RDE). Oxidation cycles between +0.6 and +1.8V were applied to ITO supporting a Pt catalyst. Cyclic voltammograms (CVs) both before and after the oxidation cycles were obtained for Pt on ITO, Hispec 4000 (a commercially available catalyst), and 40wt.% Pt dispersed in-house on Vulcan XC-72R. Pt on ITO showed significantly better electrochemical stability, as determined by the relative change in electrochemically active surface area after cycling. Hydrogen desorption peaks in the CVs existed even after 100 cycles from 0.6 to 1.8V for Pt on ITO. On the other hand, most of the active surface area was lost after 100 cycles of the Hispec 4000 catalyst. The 40wt.% Pt on Vulcan made in-house also lost most of its active area after only 50 cycles. Pt on ITO was significantly more electrochemically stable than both Hispec 4000 and Pt on Vulcan XC-72R. In this study, it was found that the Pt on ITO had average crystallite sizes of 13nm for Pt and 38nm for ITO. Pt on ITO showed extremely high thermal stability, with only {approx}1wt.% loss of material for ITO versus {approx}57wt.% for Hispec 4000 on heating to 1000{sup o}C. The TEM data show Pt clusters dispersed on small crystalline ITO particles. The SEM data show octahedral shaped ITO particles supporting Pt. (author)

  5. Hierarchical nanostructured hollow spherical carbon with mesoporous shell as a unique cathode catalyst support in proton exchange membrane fuel cell.

    Science.gov (United States)

    Fang, Baizeng; Kim, Jung Ho; Kim, Minsik; Kim, Minwoo; Yu, Jong-Sung

    2009-03-07

    Hierarchical nanostructured spherical carbon with hollow macroporous core in combination with mesoporous shell has been explored to support Pt cathode catalyst with high metal loading in proton exchange membrane fuel cell (PEMFC). The hollow core-mesoporous shell carbon (HCMSC) has unique structural characteristics such as large specific surface area and mesoporous volume, ensuring uniform dispersion of the supported high loading (60 wt%) Pt nanoparticles with small particle size, and well-developed three-dimensionally interconnected hierarchical porosity network, facilitating fast mass transport. The HCMSC-supported Pt(60 wt%) cathode catalyst has demonstrated markedly enhanced catalytic activity toward oxygen reduction and greatly improved PEMFC polarization performance compared with carbon black Vulcan XC-72 (VC)-supported ones. Furthermore, the HCMSC-supported Pt(40 wt%) or Pt(60 wt%) outperforms the HCMSC-supported Pt(20 wt%) even at a low catalyst loading of 0.2 mg Pt cm(-2) in the cathode, which is completely different from the VC-supported Pt catalysts. The capability of supporting high loading Pt is supposed to accelerate the commercialization of PEMFC due to the anticipated significant reduction in the amount of catalyst support required, diffusion layer thickness and fabricating cost of the supported Pt catalyst electrode.

  6. Enhanced life of proton exchange membrane fuel cell catalysts using perfluorosulfonic acid stabilized carbon support

    International Nuclear Information System (INIS)

    Cheng Niancai; Mu Shichun; Chen Xiaojing; Lv Haifeng; Pan Mu; Edwards, Peter P.

    2011-01-01

    We report a new and simple solution to increase life of Pt/C catalysts using the proton-conducting polymer (perfluorosulfonic acid, PFSA) stabilized carbon support (denoted these catalysts as Pt/NFC catalysts) as compared to conventional Pt/C catalysts commonly used in PEM fuel cells. A high catalytic activity of the catalyst is observed by both CV (cyclic voltammetry) and ORR (oxygen reduction reaction) measurements. Especially, our own catalysts have a 60% better life as compared to Pt/C under electrochemically accelerated durability test conditions. The loss rate of electrochemical active area (ECA) for Pt/NFC catalysts is only 0.007 m 2 g -1 cycle -1 , compared to a value of 0.011 m 2 g -1 cycle -1 for Pt/C.

  7. 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

  8. 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.

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

    NARCIS (Netherlands)

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

    2002-01-01

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

  10. Preparation and application of zirconium sulfate supported on SAPO-34 molecular sieve as solid acid catalyst for esterification

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Dongyan, E-mail: xdy0156@sina.com; Ma, Hong; Cheng, Fei

    2014-05-01

    Graphical abstract: - Highlights: • SAPO-34 supported zirconium sulfate solid acid catalyst was prepared. • Esterification of acetic acid with ethanol can be catalyzed by ZS/SAPO-34. • The hydration of ZS is vital to the acidic property and catalytic performance. • The ZS/SAPO-34 catalyst treated at 200 °C shows good reusability. - Abstract: Zirconium sulfate (ZS) was supported on SAPO-34 molecular sieve by using an incipient wetness impregnation method with zirconium sulfate as the precursor. The as-prepared catalysts were used as solid acid catalyst for esterification reaction of acetic acid with ethanol. The influence of calcination temperature on the acidic property, catalytic activity, and reusability of ZS/SAPO-34 catalysts were mainly investigated. FT-IR, SEM, EDS and TG analysis have been carried out to demonstrate the characteristics of ZS/SAPO-34 catalysts. It was found that the 30 wt%ZS/SAPO-34 catalysts display the property of superacid irrespective of calcination temperature. The ZS/SAPO-34 catalyst treated at 200 °C can enhance the interaction between the supported ZS and SAPO-34 and keep the catalyst remaining substantially active after several reaction cycles. However, further increasing calcination temperature will cause the transfer of ZS from hydrate to anhydrous phase, and thus the decrease of activity.

  11. Preparation and application of zirconium sulfate supported on SAPO-34 molecular sieve as solid acid catalyst for esterification

    International Nuclear Information System (INIS)

    Xu, Dongyan; Ma, Hong; Cheng, Fei

    2014-01-01

    Graphical abstract: - Highlights: • SAPO-34 supported zirconium sulfate solid acid catalyst was prepared. • Esterification of acetic acid with ethanol can be catalyzed by ZS/SAPO-34. • The hydration of ZS is vital to the acidic property and catalytic performance. • The ZS/SAPO-34 catalyst treated at 200 °C shows good reusability. - Abstract: Zirconium sulfate (ZS) was supported on SAPO-34 molecular sieve by using an incipient wetness impregnation method with zirconium sulfate as the precursor. The as-prepared catalysts were used as solid acid catalyst for esterification reaction of acetic acid with ethanol. The influence of calcination temperature on the acidic property, catalytic activity, and reusability of ZS/SAPO-34 catalysts were mainly investigated. FT-IR, SEM, EDS and TG analysis have been carried out to demonstrate the characteristics of ZS/SAPO-34 catalysts. It was found that the 30 wt%ZS/SAPO-34 catalysts display the property of superacid irrespective of calcination temperature. The ZS/SAPO-34 catalyst treated at 200 °C can enhance the interaction between the supported ZS and SAPO-34 and keep the catalyst remaining substantially active after several reaction cycles. However, further increasing calcination temperature will cause the transfer of ZS from hydrate to anhydrous phase, and thus the decrease of activity

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

    Science.gov (United States)

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

    2014-11-01

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

  13. Extended X-ray absorption fine structure (EXAFS) studies of supported catalysts

    International Nuclear Information System (INIS)

    Joyner, R.W.

    1979-01-01

    Since the rebirth of interest in extended X-ray absorption fine structure there have been several studies of systems of catalytic interest. This note is a preliminary account of an investigation of supported platinum catalysts and NiO/Al 2 O 3 catalysts. Experiments were performed on pressed disc samples at the DESY synchrotron, Hamburg, using the EXAFS spectrometer. The synchrotron operated at 7 GeV energy with a circulating current of approximately 4 mA; spectrum accumulation time was typically 45 minutes. (author)

  14. 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

  15. Hydrogen recombiner catalyst test supporting data

    International Nuclear Information System (INIS)

    Britton, M.D.

    1995-01-01

    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

  16. 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.

  17. Enhanced life of proton exchange membrane fuel cell catalysts using perfluorosulfonic acid stabilized carbon support

    Energy Technology Data Exchange (ETDEWEB)

    Cheng Niancai [State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, 430070 (China); Mu Shichun, E-mail: msc@whut.edu.c [State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, 430070 (China); Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, OX1 3QR (United Kingdom); Chen Xiaojing; Lv Haifeng; Pan Mu [State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, 430070 (China); Edwards, Peter P. [Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, OX1 3QR (United Kingdom)

    2011-02-01

    We report a new and simple solution to increase life of Pt/C catalysts using the proton-conducting polymer (perfluorosulfonic acid, PFSA) stabilized carbon support (denoted these catalysts as Pt/NFC catalysts) as compared to conventional Pt/C catalysts commonly used in PEM fuel cells. A high catalytic activity of the catalyst is observed by both CV (cyclic voltammetry) and ORR (oxygen reduction reaction) measurements. Especially, our own catalysts have a 60% better life as compared to Pt/C under electrochemically accelerated durability test conditions. The loss rate of electrochemical active area (ECA) for Pt/NFC catalysts is only 0.007 m{sup 2} g{sup -1} cycle{sup -1}, compared to a value of 0.011 m{sup 2} g{sup -1} cycle{sup -1} for Pt/C.

  18. Pd nanoparticles Supported on Cellulose as a catalyst for vanillin conversion in aqueous media.

    Science.gov (United States)

    Li, Dan-Dan; Zhang, Jia-Wei; Cai, Chun

    2018-05-17

    Palladium nanoparticles were firstly anchored on modified biopolymer as an efficient catalyst for biofuel upgradation. Fluorinated compounds was grafted onto cellulose to obtain amphiphilic supports for on water reactions. Pd catalyst was prepared by straightforward deposition of metal nanoparticles on modified cellulose. The catalyst exhibited excellent catalytic activity and selectivity in hydrodeoxygenation of vanillin (a typical model compound of lignin) to 2-methoxy-4-methylphenol under atmospheric hydrogen pressure in neat water without any other additives under mild conditions.

  19. 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.

  20. Methanol-Tolerant Platinum-Palladium Catalyst Supported on Nitrogen-Doped Carbon Nanofiber for High Concentration Direct Methanol Fuel Cells.

    Science.gov (United States)

    Kim, Jiyoung; Jang, Jin-Sung; Peck, Dong-Hyun; Lee, Byungrok; Yoon, Seong-Ho; Jung, Doo-Hwan

    2016-08-15

    Pt-Pd catalyst supported on nitrogen-doped carbon nanofiber (N-CNF) was prepared and evaluated as a cathode electrode of the direct methanol fuel cell (DMFC). The N-CNF, which was directly synthesized by the catalytic chemical vapor deposition from acetonitrile at 640 °C, was verified as having a change of electrochemical surface properties such as oxygen reduction reaction (ORR) activities and the electrochemical double layer compared with common carbon black (CB). To attain the competitive oxygen reduction reaction activity with methanol tolerance, the Pt and Pd metals were supported on the CB or the N-CNF. The physical and electrochemical characteristics of the N-CNF-supported Pt-Pd catalyst were examined and compared with catalyst supported on the CB. In addition, DMFC single cells using these catalysts as the cathode electrode were applied to obtain I-V polarization curves and constant current operating performances with high-concentration methanol as the fuel. Pt-Pd catalysts had obvious ORR activity even in the presence of methanol. The higher power density was obtained at all the methanol concentrations when it applied to the membrane electrode assembly (MEA) of the DMFC. When the N-CNF is used as the catalyst support material, a better performance with high-concentration methanol is expected.

  1. Methanol-Tolerant Platinum-Palladium Catalyst Supported on Nitrogen-Doped Carbon Nanofiber for High Concentration Direct Methanol Fuel Cells

    Directory of Open Access Journals (Sweden)

    Jiyoung Kim

    2016-08-01

    Full Text Available Pt-Pd catalyst supported on nitrogen-doped carbon nanofiber (N-CNF was prepared and evaluated as a cathode electrode of the direct methanol fuel cell (DMFC. The N-CNF, which was directly synthesized by the catalytic chemical vapor deposition from acetonitrile at 640 °C, was verified as having a change of electrochemical surface properties such as oxygen reduction reaction (ORR activities and the electrochemical double layer compared with common carbon black (CB. To attain the competitive oxygen reduction reaction activity with methanol tolerance, the Pt and Pd metals were supported on the CB or the N-CNF. The physical and electrochemical characteristics of the N-CNF–supported Pt-Pd catalyst were examined and compared with catalyst supported on the CB. In addition, DMFC single cells using these catalysts as the cathode electrode were applied to obtain I-V polarization curves and constant current operating performances with high-concentration methanol as the fuel. Pt-Pd catalysts had obvious ORR activity even in the presence of methanol. The higher power density was obtained at all the methanol concentrations when it applied to the membrane electrode assembly (MEA of the DMFC. When the N-CNF is used as the catalyst support material, a better performance with high-concentration methanol is expected.

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

    International Nuclear Information System (INIS)

    Arthur, Ernest Evans; Li, Fang; Momade, Francis W.Y.; Kim, Hern

    2014-01-01

    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

  3. 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.)

  4. 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 ...

  5. Metathesis of cardanol over Ru catalysts supported on mesoporousmolecular sieve SBA-15

    Czech Academy of Sciences Publication Activity Database

    Shinde, Tushar; Varga, Vojtěch; Polášek, Miroslav; Horáček, Michal; Žilková, Naděžda; Balcar, Hynek

    2014-01-01

    Roč. 478, MAY 2014 (2014), s. 138-145 ISSN 0926-860X R&D Projects: GA ČR(CZ) GAP106/12/0189 Institutional support: RVO:61388955 Keywords : cardanol * metathesis * supported catalysts Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.942, year: 2014

  6. Hydrogen production by steam reforming of liquefied natural gas (LNG) over nickel catalysts supported on cationic surfactant-templated mesoporous aluminas

    Science.gov (United States)

    Seo, Jeong Gil; Youn, Min Hye; Park, Sunyoung; Jung, Ji Chul; Kim, Pil; Chung, Jin Suk; Song, In Kyu

    Two types of mesoporous γ-aluminas (denoted as A-A and A-S) are prepared by a hydrothermal method under different basic conditions using cationic surfactant (cetyltrimethylammonium bromide, CTAB) as a templating agent. A-A and A-S are synthesized in a medium of ammonia solution and sodium hydroxide solution, respectively. Ni/γ-Al 2O 3 catalysts (Ni/A-A and Ni/A-S) are then prepared by an impregnation method, and are applied to hydrogen production by steam reforming of liquefied natural gas (LNG). The effect of a mesoporous γ-Al 2O 3 support on the catalytic performance of Ni/γ-Al 2O 3 is investigated. The identity of basic solution strongly affects the physical properties of the A-A and A-S supports. The high surface-area of the mesoporous γ-aluminas and the strong metal-support interaction of supported catalysts greatly enhance the dispersion of nickel species on the catalyst surface. The well-developed mesopores of the Ni/A-A and Ni/A-S catalysts prohibit the polymerization of carbon species on the catalyst surface during the reaction. In the steam reforming of LNG, both Ni/A-A and Ni/A-S catalysts give better catalytic performance than the nickel catalyst supported on commercial γ-Al 2O 3 (Ni/A-C). In addition, the Ni/A-A catalyst is superior to the Ni/A-S catalyst. The relatively strong metal-support interaction of Ni/A-A catalyst effectively suppresses the sintering of metallic nickel and the carbon deposition in the steam reforming of LNG. The large pores of the Ni/A-A catalyst also play an important role in enhancing internal mass transfer during the reaction.

  7. Isotopic exchange between deuterium and neohexane on supported platinum and palladium catalysts

    International Nuclear Information System (INIS)

    Eskinazi, V.

    1979-01-01

    The isotopic exchange reaction between neohexane and deuterium on supported Pt/SiO 2 and Pd/SiO 2 catalysts has been investigated in the temperature range 86.5 to 110 0 C. Rates of exchange were studied as functions of percentage of metal atoms exposed, the conditions of catalyst pretreatment, and the reaction temperature. The rates of exchange were not strongly dependent upon percentage exposed; however, the relative yields of d 1 through d 5 in the ethyl moiety or neohexane were dependent on the percentage metal atoms exposed. The Pt/SiO 2 catalysts were found to be more active for exchange than the Pd/SiO 2 catalysts by an order of magnitude. Both the turnover frequencies and the exchange pattern were observed to be influenced by the pretreatment of the catalyst. Maxima in the exchange pattern occurred at d 3 and d 5 in the case of Pt/SiO 2 and at d 5 only in the case of the Pd/SiO 2 catalysts. In order to account for the d 3 maximum observed for Pt catalysts, some extension of the Horiuti-Polanyi mechanism is required. Mechanisms by which the d 3 species might be formed are proposed and discussed. On Pd/SiO 2 catalysts exchange occurs preferentially in the ethyl substituent of the quaternary carbon atom rather than on the three methyl substituents of the quaternary carbon atom. Such preference is not observed on Pt/SiO 2 catalysts; in fact, in some cases, this preference is reversed. Whenever exchange occurs in the three methyl substituents, mostly the d 1 product is obtained. For Pt/SiO 2 catalysts, the exchange pattern appears to be influenced by steric effects, but the data suggest that factors other than steric effects are important on Pd

  8. Highly dispersed metal catalyst

    Science.gov (United States)

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

    2016-11-08

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

  9. 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.

  10. Session 4: High-throughput screening of supported catalysts for CO{sub x}-free hydrogen production from ammonia

    Energy Technology Data Exchange (ETDEWEB)

    Hongchao, Liu; Hua, Wang; Zhongmin, Liu; Jianghan, Shen [Natural Gas Utilization and Applied Catalysis Laboratory, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, P. R. (China)

    2004-07-01

    In this paper, we used a multi-stream mass spectrometer screening (MSMSS) technique and a multi-stream reactor to select promising candidates from supported transition metal catalyst library, and then combinatorially nitrided and tested silica and SAB-15 supported Mo catalysts for hydrogen production from ammonia. (authors)

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

    Czech Academy of Sciences Publication Activity Database

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

    2018-01-01

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

  12. Hydrocracking of α-Cellulose Using Co, Ni, and Pd Supported on Mordenite Catalysts

    Directory of Open Access Journals (Sweden)

    Wega Trisunaryanti

    2018-02-01

    Full Text Available Hydrocracking of α-cellulose has been conducted in a semi-batch reactor at 400, 450, and 500 °C with hydrogen flow (30 mL/min. for 4 h. Mordenite (MOR and Co, Ni and Pd metal supported on the MOR were used as solid catalysts. The catalysts were characterized using X-ray Diffractometer (XRD, Fourier Transform Infrared (FTIR spectroscopy, and Scanning Electron Microscopy (SEM to evaluate the physical-chemical properties. Energy Dispersive X-ray (EDX and Inductively Coupled Plasma (ICP were used to analyze the amount of metal impregnated on the catalysts. The liquid product was analyzed using Gas Chromatograph-Mass Spectroscopy (GC-MS. Thermal hydrocracking was also conducted at 450 °C with the amount of liquid product was 37.86 wt.%. The highest liquid conversion obtained by mordenite catalyst was 94.66 wt.% at 450 °C and the highest liquid conversion (98.08 wt.% was reached by Pd/MOR catalyst at 400 °C.

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

    DEFF Research Database (Denmark)

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

    2007-01-01

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

  14. Preparation of SnO{sub 2}-CNTs supported Pt catalysts and their electrocatalytic properties for ethanol oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Pang, H.L.; Lu, J.P. [State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082 (China); Chen, J.H. [State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082 (China)], E-mail: chenjinhua@hnu.cn; Huang, C.T.; Liu, B.; Zhang, X.H. [State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082 (China)

    2009-03-30

    SnO{sub 2}-carbon nanotubes (CNTs) composites were prepared by sol-gel method, and characterized by scanning electron microscopy and X-ray diffraction. Due to high stability in diluted acidic solution, SnO{sub 2}-CNTs composites were selected as the catalyst support and second catalyst for ethanol electrooxidation. The electrocatalytic properties of the SnO{sub 2}-CNTs supported platinum (Pt) catalyst (Pt/SnO{sub 2}-CNTs) for ethanol oxidation have been investigated by typical electrochemical methods. Under the same mass loading of Pt, the Pt/SnO{sub 2}-CNTs catalyst shows higher electrocatalytic activity and better long-term cycle stability than Pt/SnO{sub 2} catalyst. Additionally, the effect of the mass ratio of CNTs to SnO{sub 2} on the electrocatalytic activity of the electrode for ethanol oxidation was investigated, and the optimum mass ratio of CNTs to SnO{sub 2} in the Pt/SnO{sub 2}-CNTs catalyst is 1/6.3.

  15. Evaluation of mechanical properties in metal wire mesh supported selective catalytic reduction (SCR) catalyst structures

    Science.gov (United States)

    Rajath, S.; Siddaraju, C.; Nandakishora, Y.; Roy, Sukumar

    2018-04-01

    The objective of this research is to evaluate certain specific mechanical properties of certain stainless steel wire mesh supported Selective catalytic reduction catalysts structures wherein the physical properties of the metal wire mesh and also its surface treatments played vital role thereby influencing the mechanical properties. As the adhesion between the stainless steel wire mesh and the catalyst material determines the bond strength and the erosion resistance of catalyst structures, surface modifications of the metal- wire mesh structure in order to facilitate the interface bonding is therefore very important to realize enhanced level of mechanical properties. One way to enhance such adhesion properties, the stainless steel wire mesh is treated with the various acids, i.e., chromic acid, phosphoric acid including certain mineral acids and combination of all those in various molar ratios that could generate surface active groups on metal surface that promotes good interface structure between the metal- wire mesh and metal oxide-based catalyst material and then the stainless steel wire mesh is dipped in the glass powder slurry containing some amount of organic binder. As a result of which the said catalyst material adheres to the metal-wire mesh surface more effectively that improves the erosion profile of supported catalysts structure including bond strength.

  16. Mechanochemical synthesis of graphene oxide-supported transition metal catalysts for the oxidation of isoeugenol to vanillin.

    Science.gov (United States)

    Franco, Ana; De, Sudipta; Balu, Alina M; Garcia, Araceli; Luque, Rafael

    2017-01-01

    Vanillin is one of the most commonly used natural products, which can also be produced from lignin-derived feedstocks. The chemical synthesis of vanillin is well-established in large-scale production from petrochemical-based starting materials. To overcome this problem, lignin-derived monomers (such as eugenol, isoeugenol, ferulic acid etc.) have been effectively used in the past few years. However, selective and efficient production of vanillin from these feedstocks still remains an issue to replace the existing process. In this work, new transition metal-based catalysts were proposed to investigate their efficiency in vanillin production. Reduced graphene oxide supported Fe and Co catalysts showed high conversion of isoeugenol under mild reaction conditions using H 2 O 2 as oxidizing agent. Fe catalysts were more selective as compared to Co catalysts, providing a 63% vanillin selectivity at 61% conversion in 2 h. The mechanochemical process was demonstrated as an effective approach to prepare supported metal catalysts that exhibited high activity for the production of vanillin from isoeugenol.

  17. Mild oxidation of methane to methanol or acetic acid on supported isolated rhodium catalysts

    Science.gov (United States)

    Shan, Junjun; Li, Mengwei; Allard, Lawrence F.; Lee, Sungsik; Flytzani-Stephanopoulos, Maria

    2017-11-01

    An efficient and direct method of catalytic conversion of methane to liquid methanol and other oxygenates would be of considerable practical value. However, it remains an unsolved problem in catalysis, as typically it involves expensive or corrosive oxidants or reaction media that are not amenable to commercialization. Although methane can be directly converted to methanol using molecular oxygen under mild conditions in the gas phase, the process is either stoichiometric (and therefore requires a water extraction step) or is too slow and low-yielding to be practical. Methane could, in principle, also be transformed through direct oxidative carbonylation to acetic acid, which is commercially obtained through methane steam reforming, methanol synthesis, and subsequent methanol carbonylation on homogeneous catalysts. However, an effective catalyst for the direct carbonylation of methane to acetic acid, which might enable the economical small-scale utilization of natural gas that is currently flared or stranded, has not yet been reported. Here we show that mononuclear rhodium species, anchored on a zeolite or titanium dioxide support suspended in aqueous solution, catalyse the direct conversion of methane to methanol and acetic acid, using oxygen and carbon monoxide under mild conditions. We find that the two products form through independent pathways, which allows us to tune the conversion: three-hour-long batch-reactor tests conducted at 150 degrees Celsius, using either the zeolite-supported or the titanium-dioxide-supported catalyst, yield around 22,000 micromoles of acetic acid per gram of catalyst, or around 230 micromoles of methanol per gram of catalyst, respectively, with selectivities of 60-100 per cent. We anticipate that these unusually high activities, despite still being too low for commercial application, may guide the development of optimized catalysts and practical processes for the direct conversion of methane to methanol, acetic acid and other useful

  18. Structure-activity relationships of carbon-supported platinum-bismuth and platinum-antimony oxidation catalysts

    CSIR Research Space (South Africa)

    Maphoru, MV

    2017-04-01

    Full Text Available Compositional and morphological studies on supported platinum are important for the improvement and expanded use of catalysts for oxidative coupling reactions. Nanocomposites consisting of 5% Pt supported on activated carbon and promoted with 5% Bi...

  19. 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.

  20. Structural consideration with respect to the thermal stability of a new platinum supported lanthanum-alumina catalyst

    International Nuclear Information System (INIS)

    Oudet, F.; Bordes, E.; Courtine, P.; Maxant, G.; Lambert, C.; Guerlet, J.P.

    1987-01-01

    The influence of lanthanum aluminate, LaAlO 3 , on the thermal stability of both alumina and platinum supported alumina catalysts is investigated. In the case of alumina, the stabilization is interpreted in terms of structural coherence between δ-Al 2 O 3 and a three-fold superstructure of LaAlO 3 . The addition of LaAlO 3 , is shown to increase both the dispersion and the resistance to sintering of the platinum supported alumina catalyst. Moreover, lanthanum hexa-aluminate (La-β-Al 2 O 3 ) is present in the platinum catalyst fired at 1150 0 C. These observations are assumed to result for the epitaxial relations between platinum and the lanthanum-alumina support. 23 refs.; 8 figs.; 2 tabs

  1. Synthesis of Carbon Nano tubes Using Anadara Granosa Shells as Catalyst Support

    International Nuclear Information System (INIS)

    Mohd Zobir Hussein; Mohd Zobir Hussein; Salwani Asyikin Zakarya; Siti Halimah Sarijo

    2011-01-01

    The synthesis of carbon nano tubes (CNTs) by chemical vapor deposition (CVD) method using natural calcite prepared from Anadara granosa shells (CS), as metal catalyst support was studied. Hexane and iron were used as carbon precursor and catalyst, respectively. The as synthesised CNTs was characterized using XRD, TEM and FESEM. From the XRD patterns the CNTs peak can be seen more incisive after purification process and from the FESEM micrographs the CNTs can be seen as a bunch of rope-like structures. (author)

  2. Magnetic nanoparticle supported phosphotungstic acid: An efficient catalyst for the synthesis of xanthene derivatives

    Science.gov (United States)

    Patel, Nipun; Katheriya, Deepak; Dadhania, Harsh; Dadhania, Abhishek

    2018-05-01

    Magnetic nanoparticle supported phosphotungstic acid (Fe3O4@SiO2-HPW) was applied as a highly efficient catalyst for the synthesis of 14H-dibenzoxanthene derivatives via condensation reaction of 2-naphthol and aryl aldehydes. The catalyst was found highly efficient for the synthesis of xanthene derivatives under solvent free condition. The catalyst showed high activity and stability during the reaction and provided excellent yield of the corresponding products in short reaction time. All the synthesized compounds were characterized through FT-IR, 1H-NMR and 13C-NMR spectroscopic techniques. Furthermore, the catalyst is magnetically recoverable and can be reused several times without significant loss of its catalytic activity.

  3. The role of support morphology on the performance of Cu/ZnO-catalyst for hydrogenation of CO{sub 2} to methanol

    Energy Technology Data Exchange (ETDEWEB)

    Tasfy, Sara Faiz Hanna, E-mail: miss25208@gmail.com; Zabidi, Noor Asmawati Mohd, E-mail: noorasmawati-mzabidi@petronas.com.my; Shaharun, Maizatul Shima, E-mail: maizats@petronas.com.my; Subbarao, Duvvuri, E-mail: duvvuri-subbarao@petronas.com.my [Department of Chemical Engineering Chemical Engineering Department of Fundamental and Applied Sciences Universiti Teknologi PETRONAS Bandar Seri Iskandar, 31750 Tronoh, Perak (Malaysia)

    2015-07-22

    The effects of SBA-15 support morphology on the activity of Cu/ZnO catalyst in the hydrogenation of CO{sub 2} to methanol was investigated. In the hydrogenation of CO{sub 2} to methanol at 210°C, 2.25 MPa, H{sub 2}/CO{sub 2} ratio of three remarkable difference was obtained using Cu/ZnO catalyst supported on SBA-15 with different morphology. The catalysts were characterized using N{sub 2}-adsorption, field emission scanning microscopy (FESEM/EDX), transmission electron microscopy (HRTEM), and temperature-programmed reduction (TPR). Characterization of the catalyst showed that support morphology, surface area, metals dispersion, and reducibility influenced the catalytic performance. On the fiber-shaped SBA-15, copper dispersion was 29 % whereas on the spherical-shaped SBA-15, the dispersion was 20 %. The experimental results showed that the catalyst supported over fiber-shaped SBA-15 exhibit higher CO{sub 2} conversion (13.96 %) and methanol selectivity (91.32 %) compare to catalyst supported over spherical-shaped SBA-15.

  4. 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.......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...

  5. The effect of catalyst support on the RWGS reaction

    International Nuclear Information System (INIS)

    Laosiripojana, N.; Sutthisripok, W.

    2004-01-01

    '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 600 o C (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

  6. 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)

    Komatsu, Tamikuni; Tomokuni, Keizou; Yamada, Issaku

    2006-01-01

    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 150-200 o C and free from difficult problems of SOx-deactivation and hydrothermal ageing of the NOx-absorption-reduction catalyst. (author)

  7. Preparation, surface characterization and performance of a Fischer-Tropsch catalyst of cobalt supported on silica nanosprings

    International Nuclear Information System (INIS)

    Kengne, Blaise-Alexis Fouetio; Alayat, Abdulbaset M.; Luo, Guanqun; McDonald, Armando G.; Brown, Justin; Smotherman, Hayden; McIlroy, David N.

    2015-01-01

    Graphical abstract: - Highlights: • Determined that the reduction of Co nanoparticles on silica nanosprings 200 °C higher than the reduction temperature of Co in a solgel support. • The high reduction temperature of Co supported on silica nanosprings is attributed to the heat transfer properties of the nanosprings due to their high surface area. Co-silica nanospring Fischer-Tropsch catalyst can be used to produce drop in fuels such as JP-4. - Abstract: The reduction of cobalt (Co) catalyst supported on silica nanosprings for Fischer-Tropsch synthesis (FTS) has been monitored by X-ray photoelectron spectroscopy (XPS) and compared to FT catalytic activity. The cobalt is present in the starting catalyst as a Co 3 O 4 spinel phase. A two-step reduction of Co 3 O 4 to CoO and then to Co 0 is observed, which is consistent with the results of H 2 -temperature programmed reduction. During the reduction the two steps occur concurrently. The deconvolution of the Co 2p core level state for the catalyst reduced at 385 °C and 1.0 × 10 −6 Torr of H 2 revealed signatures of Co 0 , CoO, and Co 3 O 4 . The reduction saturates at a Co o concentration of approximately 41% after 20 h, which correlates with the activity and lifetime of the catalyst during FTS testing. Conversely, at 680 °C and 10 Torr of H 2 , the catalyst is completely reduced after 10 h. The evolution of the Co d-band at the Fermi level in the valence band XPS spectrum definitively verifies the metallic phase of Co. FTS evaluation of the Co/NS catalyst reduced at 609 °C showed higher production rate (3-fold) of C 6 -C 17 hydrocarbons than the catalyst reduced at 409 °C and is consistent with the XPS analysis.

  8. 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

    2016-06-08

    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. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

    KAUST Repository

    Zwaschka, Gregor; Rondelli, Manuel; Krause, Maximilian; Rö tzer, Marian David; Hedhili, Mohamed N.; Heiz, Ulrich; Basset, Jean-Marie; Schweinberger, Florian; D'Elia, Valerio

    2018-01-01

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

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

    KAUST Repository

    Zwaschka, Gregor

    2018-01-22

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

  11. Acidity, oxophilicity and hydrogen sticking probability of supported metal catalysts for hydrodeoxygenation process

    Science.gov (United States)

    Lup, A. Ng K.; Abnisa, F.; Daud, W. M. A. W.; Aroua, M. K.

    2018-03-01

    Hydrodeoxygenation is an oxygen removal process that occurs in the presence of hydrogen and catalysts. This study has shown the importance of acidity, oxophilicity and hydrogen sticking probability of supported metal catalysts in having high hydrodeoxygenation activity and selectivity. These properties are required to ensure the catalyst has high affinity for C-O or C=O bonds and the capability for the adsorption and activation of H2 and O-containing compounds. A theoretical framework of temperature programmed desorption technique was also discussed for the quantitative understanding of these properties. By using NH3-TPD, the nature and abundance of acid sites of catalyst can be determined. By using H2-TPD, the nature and abundance of metallic sites can also be determined. The desorption activation energy could also be determined based on the Redhead analysis of TPD spectra with different heating rates.

  12. Mesoporous molecular sieves as advanced supports for olefin metathesis catalysts

    Czech Academy of Sciences Publication Activity Database

    Balcar, Hynek; Čejka, Jiří

    2013-01-01

    Roč. 257, 21-22 (2013), s. 3107-3124 ISSN 0010-8545 R&D Projects: GA AV ČR IAA400400805; GA ČR GBP106/12/G015 Institutional support: RVO:61388955 Keywords : Olefin metathesis * mesoporous molecular sieves * Heterogeneous catalysts Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 12.098, year: 2013

  13. 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

  14. Kinetic modelling of slurry polymerization of ethylene with a polymer supported Ziegler-Natta catalyst (hydrogen)

    Energy Technology Data Exchange (ETDEWEB)

    Shariati, A.

    1996-12-31

    The kinetics of polymerization of ethylene catalyzed by a polymer supported Ziegler-Natta catalyst were investigated in a semi-batch reactor system. The influences of six polymerization variables were investigated using a central composite design. The variables were monomer partial pressure, catalyst loading, co-catalyst loading, catalyst particle size and hydrogen to monomer ratio. The influence of temperature on rate and polymer properties were investigated. Empirical models were fitted to the experimental data to quantify the effects of the polymerization variables on the rate characteristics and polymer properties. The rate of polymerization exhibited a first order dependency with respect to monomer partial pressure, but a nonlinear relationship with respect to catalyst loading. In the absence of hydrogen, the polymerization rate showed a non-decaying profile at the centre point conditions for the other variables. Catalyst loading and catalyst particle size had a negligible effect on weight-and-number-average molecular weights, while increasing co-catalysts loading lowered the molecular weights, as did increased temperature and hydrogen concentration. refs., figs.

  15. 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

  16. Support Screening Studies on the Hydrogenation of Levulinic Acid to γ-Valerolactone in Water Using Ru Catalysts

    Directory of Open Access Journals (Sweden)

    Anna Piskun

    2016-08-01

    Full Text Available γ-Valerolactone (GVL has been identified as a sustainable platform chemical for the production of carbon-based chemicals. Here we report a screening study on the hydrogenation of levulinic acid (LA to GVL in water using a wide range of ruthenium supported catalysts in a batch set-up (1 wt. % Ru, 90 °C, 45 bar of H2, 2 wt. % catalyst on LA. Eight monometallic catalysts were tested on carbon based(C, carbon nanotubes (CNT and inorganic supports (Al2O3, SiO2, TiO2, ZrO2, Nb2O5 and Beta-12.5. The best result was found for Ru/Beta-12.5 with almost quantitative LA conversion (94% and 66% of GVL yield after 2 h reaction. The remaining product was 4-hydroxypentanoic acid (4-HPA. Catalytic activity for a bimetallic RuPd/TiO2 catalyst was by far lower than for the monometallic Ru catalyst (9% conversion after 2 h. The effects of relevant catalyst properties (average Ru nanoparticle size, Brunauer-Emmett-Teller (BET surface area, micropore area and total acidity on catalyst activity were assessed.

  17. Supported liquid phase catalyst coating in micro flow Mizoroki-Heck reaction

    NARCIS (Netherlands)

    Stouten, S.C.; Noël, T.; Wang, Q.; Hessel, V.

    2015-01-01

    A Supported Liquid Phase Catalyst (SLPC) coating was successfully applied for the Mizoroki–Heck reaction in micro flow. Foremost, extended on stream operation was enabled and the on stream performance stability was verified. Stable catalytic activity was achieved during two consecutive runs totaling

  18. Turbostratic carbon supported palladium as an efficient catalyst for reductive purification of water from trichloroethylene

    Directory of Open Access Journals (Sweden)

    Emil Kowalewski

    2017-12-01

    Full Text Available This work investigates the catalytic properties of turbostratic carbon supported Pd catalyst in hydrodechlorination of trichloroethylene (TCE HDC in aqueous phase. 1.57 wt% Pd/C was thoroughly characterized by BET, TPHD, CO chemisorption, PXRD, STEM, XPS and used as the catalyst in removal of trichloroethylene from drinking water in batch and continuous-flow reactors. The studies showed that catalytic performance of Pd/C depended on the hydrophobicity and textural properties of carbon support, which influenced noble metal dispersion and increased catalyst tolerance against deactivation by chlorination. Palladium in the form of uniformly dispersed small (~3.5 nm nanoparticles was found to be very active and stable in purification of water from TCE both in batch and continuous-flow operation.

  19. 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.

  20. Hydrogen production in membrane reactors using Rh catalysts on binary supports

    Energy Technology Data Exchange (ETDEWEB)

    Carrara, Carlos; Roa, Alejandro; Cornaglia, Laura; Lombardo, Eduardo A. [Instituto de Investigaciones en Catalisis y Petroquimica (FIQ, UNL-CONICET), Sgo del Estero 2829-3000 Santa Fe (Argentina); Mateos-Pedrero, Cecilia; Ruiz, Patricio [Unite de Catalyse et Chimie des Materiaux Divises, Universite Catholique de Louvain, Place Croix du Sud 2/17, 1348 Louvain-la Neuve (Belgium)

    2008-04-15

    The binary supports employed in this work were prepared by different methods. The Ti(7%)-MgO and the Ti(13%)-SiO{sub 2} were obtained using the grafting technique. The La(27%)-SiO{sub 2} was obtained through the incipient wetness impregnation with La(NO{sub 3}){sub 3} of Aerosil 300, previously calcined at 1173 K. The Rh was incorporated to these supports by wet impregnation. The catalysts were first evaluated for the CH{sub 4} + CO{sub 2} reaction in a fixed-bed reactor. They were found to be active and stable as to justify their use in the membrane reactor, which was operated at 823 K achieving methane conversions up to twice as much as the equilibrium values. In all cases, the activity of the Rh solids remained constant after 120 h on stream with very little formation of carbonaceous residues only detected through LRS. The catalysts were characterized through either hydrogen or carbon monoxide chemisorption, TPR, XRD, LRS and XPS. The Rh(0.6)/La-SiO{sub 2} catalyst showed a high metal dispersion that remained constant after use and the highest capacity to restore the CH{sub 4} + CO{sub 2} equilibrium when H{sub 2} was permeated out of the reaction section. The Rh(0.8)/Ti-MgO showed the highest Rh/oxide interaction associated with the lowest capacity to restore the reaction equilibrium. The Rh(0.8)/Ti-SiO{sub 2} exhibited an intermediate activity due in part to the partial segregation of the TiO{sub 2} upon calcinations and the subsequent appearance of small Rh crystallites in the used catalysts. (author)

  1. Synthesis and characterization of molybdenum catalysts supported on γ-Al2O3-CeO2 composite oxides

    International Nuclear Information System (INIS)

    Farooq, Muhammad; Ramli, Anita; Subbarao, Duvvuri

    2012-01-01

    The physical and chemical properties of a catalyst play a vital role in various industrial applications. Molybdenum catalysts supported on γ-Al 2 O 3 and γ-Al 2 O 3 -CeO 2 mixed oxides with varying loading of CeO 2 (5, 10, 15, 20 wt% with respect to γ-Al 2 O 3 ) 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 CeO 2 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.

  2. Mechanochemical synthesis of graphene oxide-supported transition metal catalysts for the oxidation of isoeugenol to vanillin

    Directory of Open Access Journals (Sweden)

    Ana Franco

    2017-07-01

    Full Text Available Vanillin is one of the most commonly used natural products, which can also be produced from lignin-derived feedstocks. The chemical synthesis of vanillin is well-established in large-scale production from petrochemical-based starting materials. To overcome this problem, lignin-derived monomers (such as eugenol, isoeugenol, ferulic acid etc. have been effectively used in the past few years. However, selective and efficient production of vanillin from these feedstocks still remains an issue to replace the existing process. In this work, new transition metal-based catalysts were proposed to investigate their efficiency in vanillin production. Reduced graphene oxide supported Fe and Co catalysts showed high conversion of isoeugenol under mild reaction conditions using H2O2 as oxidizing agent. Fe catalysts were more selective as compared to Co catalysts, providing a 63% vanillin selectivity at 61% conversion in 2 h. The mechanochemical process was demonstrated as an effective approach to prepare supported metal catalysts that exhibited high activity for the production of vanillin from isoeugenol.

  3. The effect of promoters on the electronic structure of ruthenium catalysts supported on carbon

    International Nuclear Information System (INIS)

    Guraya, Monica; Sprenger, Susanne; Rarog-Pilecka, Wioletta; Szmigiel, Dariusz; Kowalczyk, Zbigniew; Muhler, Martin

    2004-01-01

    Alkali- and earth-alkali-promoted ruthenium catalysts supported on graphitized carbon were investigated by means of X-ray and ultraviolet photoelectron spectroscopy (XPS and UPS) in order to study the effect of promoters on the electronic structure of this metal-support system. Samples were measured as prepared and after thorough reduction in hydrogen. The C 1s spectra of reduced alkali-promoted catalysts showed a shift towards higher binding energies and an asymmetric broadening. Neither non-promoted nor Ba-promoted Ru/C samples exhibited such a behaviour after similar treatments. The most important feature in the UP spectra of the reduced alkali-promoted catalysts was the appearance of a well defined Fermi edge absent in the semimetal-like electronic structure of graphite. No significant effects appeared in the case of non-promoted or Ba-promoted catalysts. The increase in the density of occupied states at the Fermi energy indicates a shift of this level into the conduction band, due to a charge transfer from the promoter to the support. This interpretation also provides an explanation for the observed higher C 1s binding energy and asymmetric broadening, due to the off-set introduced in the binding energy scale and the increasing probability of inelastic excitations near the Fermi level. In addition to photoelectron spectroscopy, low energy ion scattering (ISS) was used to obtain information about the localisation of the promoters. Based on the mild sputtering effect during prolonged series of spectra, it was possible to conclude that potassium covers both the carbon support and the Ru metal particles

  4. Carbon-supported cubic CoSe2 catalysts for oxygen reduction reaction in alkaline medium

    International Nuclear Information System (INIS)

    Feng Yongjun; Alonso-Vante, Nicolas

    2012-01-01

    Highlights: ► Cubic CoSe 2 a non-precious metal electrocatalyst for oxygen reduction in KOH. ► The catalyst shows four-electron transfer pathway in overall reaction. ► Catalyst has higher methanol tolerance than commercial Pt/C catalyst. - Abstract: A Carbon-supported CoSe 2 nanocatalyst has been developed as an alternative non-precious metal electrocatalyst for oxygen reduction reaction (ORR) in alkaline medium. The catalyst was prepared via a surfactant-free route and its electrocatalytic activity for the ORR has been investigated in detail in 0.1 M KOH electrolyte at 25 °C using rotating disk electrode (RDE) and rotating ring-disk electrode (RRDE) techniques. The prepared catalyst showed promising catalytic activity towards ORR in a four-electron transfer pathway and higher tolerance to methanol compared to commercial Pt/C catalyst in 0.1 M KOH. To some extent, the increase of CoSe 2 loading on the electrode favors a faster reduction of H 2 O 2 intermediate to H 2 O.

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

    Directory of Open Access Journals (Sweden)

    Abdulmajid Alshaibani

    2017-02-01

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

  6. Development of super thin foil metal supported catalyst; Chousuhaku metal tantai shokubai no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Sanji, F; Takada, T [Toyota Motor Corp., Aichi (Japan)

    1997-10-01

    In order to improve warm-up performance, high heat resistance and long life durability of catalysts, the reduction of the metal support heat capacity has been focused. The effects of both reducing foil thickness and lowering cell density on low heat capacity have been investigated. As a result of engine bench and vehicle test, it was apparent that the reduction of foil thickness has greater effects. Newly developed 30 {mu} m foil thickness metal supported catalyst has quicker warm-up performance, and its structural durability up to 950degC is confirmed. 3 refs., 11 figs., 1 tab.

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

    Directory of Open Access Journals (Sweden)

    Jie Fu

    2015-12-01

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

  8. Enhanced hydrogen reaction kinetics of nanostructured Mg-based composites with nanoparticle metal catalysts dispersed on supports

    International Nuclear Information System (INIS)

    Yoo, Yeong; Tuck, Mark; Kondakindi, Rajender; Seo, Chan-Yeol; Dehouche, Zahir; Belkacemi, Khaled

    2007-01-01

    Hydrogen reaction kinetics of nanocrystalline MgH 2 co-catalyzed with Ba 3 (Ca 1+x Nb 2-x )O 9-δ (BCN) proton conductive ceramics and nanoparticle bimetallic catalyst of Ni/Pd dispersed on single wall carbon nanotubes (SWNTs) support has been investigated. The nanoparticle bimetallic catalysts of Ni/Pd supported by SWNTs were synthesized based on a novel polyol method using NiCl 2 .6H 2 O, PdCl 2 , NaOH and ethylene glycol (EG). The nanostructured Mg composites co-catalyzed with BCN and bimetallic supported catalysts exhibited stable hydrogen desorption capacity of 6.3-6.7 wt.% H 2 and the significant enhancement of hydrogen desorption kinetics at 230-300 deg. C in comparison to either non-catalyzed MgH 2 or the nanocomposite of MgH 2 catalyzed with BCN

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

    OpenAIRE

    Zhengyu Bai; Rumeng Huang; Lu Niu; Qing Zhang; Lin Yang; Jiujun Zhang

    2015-01-01

    In this paper, a catalyst of hollow PdCu alloy nanocubes supported on nitrogen-doped graphene support (H-PdCu/ppy-NG) is successfully synthesized using a simple one-pot template-free method. Two other catalyst materials such as solid PdCu alloy particles supported on this same nitrogen-doped graphene support (PdCu/ppy-NG) and hollow PdCu alloy nanocubes supported on the reduced graphene oxide support (H-PdCu/RGO) are also prepared using the similar synthesis conditions for comparison. It is f...

  10. Commercial application of titania-supported hydrodesulfurization catalysts in the production of hydrogen using full-range FCC off-gas

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Shaohu [SINOPEC Wuhan Branch, Qingshan, Wuhan 430082 (China); Shen, Binglong; Qu, Lianglong [Beijing Haishunde Titanium Catalyst Co. Ltd., A-1 North East-Ring Road, Beijing Economic-Technological Development Area, Beijing 100176 (China)

    2004-11-24

    This paper provides an alternative for low-cost feed used for on-purpose hydrogen production. Full-range FCC off-gas was applied to steam-reforming process as feed after treating with hydrogenation and hydrodesulfurization catalysts. Commercial run results were reported with novel TiO{sub 2}-supported Mo-based catalysts, T205A-1 and T205. The processes of catalysts loading, sulfidation, start-up and long-term run were described in details. Long-term run showed that TiO{sub 2}-supported Mo catalysts have good low-temperature hydrogenation activity, excellent HDS activity, and outstanding stability. Use of FCC off-gas as feed for hydrogen production is quite promising and will increase margins for refiners today.

  11. De-oxygenation of CO2 by using Hydrogen, Carbon and Methane over Alumina-Supported Catalysts

    Directory of Open Access Journals (Sweden)

    R.Y. Raskar

    2012-06-01

    Full Text Available The de-oxygenation of CO2 was explored by using hydrogen, methane, carbon etc., over alumina supported catalysts. The alumina-supported ruthenium, rhodium, platinum, molybdenum, vanadium and magnesium catalysts were first reduced in hydrogen atmosphere and then used for the de-oxygenation of CO2. Furthermore, experimental variables for the de-oxygenation of CO2 were temperature (range 50 to 650 oC, H2/CO2 mole ratios (1.0 to 5, and catalyst loading (0.5 to 10 wt %. During the de-oxygenation of CO2 with H2 or CH4 or carbon, conversion of CO2, selectivity to CO and CH4 were estimated. Moreover, 25.4 % conversion of CO2 by hydrogen was observed over 1 wt% Pt/Al2O3 catalyst at 650 oC with 33.8 % selectivity to CH4. However, 8.1 to 13.9 % conversion of CO2 was observed over 1 wt% Pt/Al2O3 catalyst at 550 oC in the presence of both H2 and CH4. Moreover, 42.8 to 79.4 % CH4 was converted with 9 to 23.1 % selectivity to CO. It was observed that the de-oxygenation of CO2 by hydrogen, carbon and methane produced carbon, CO and CH4. © 2012 BCREC UNDIP. All rights reservedReceived: 6th February 2012; Revised: 23rd April 2012; Accepted: 24th April 2012[How to Cite: R. Y. Raskar, K. B. Kale, A. G. Gaikwad. (2011. De-oxygenation of CO2 by using Hydrogen, Carbon and Methane over Alumina-Supported Catalysts. Bulletin of Chemical Reaction Engineering & Catalysis, 7 (1: 59-69.  doi:10.9767/bcrec.7.1.1631.59-69][How to Link / DOI: http://dx.doi.org/10.9767/bcrec.7.1.1631.59-69 ] | View in 

  12. 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.

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

    Science.gov (United States)

    Lee, Hochun; Jung, Yongju; Kim, Seok

    2012-02-01

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

  14. Chelating agent-assisted heat treatment of a carbon-supported iron oxide nanoparticle catalyst for PEMFC.

    Science.gov (United States)

    Liu, Shyh-Jiun; Huang, Chia-Hung; Huang, Chun-Kai; Hwang, Weng-Sing

    2009-08-28

    Iron complexes were supported on commercial carbon black and heat treated to create FeO(x)/C catalysts that showed a larger normalized current density and normalized power density than commercial Pt/C catalysts; the coordination number of the iron complexes used affected the formation of the active site for oxygen reduction in PEMFC.

  15. Multi-wall carbon nanotubes supported molybdenyl acetylacetonate: Efficient and highly reusable catalysts for epoxidation of alkenes with tert-butyl hydroperoxide

    International Nuclear Information System (INIS)

    Esnaashari, Fariba; Moghadam, Majid; Mirkhani, Valiollah; Tangestaninejad, Shahram; Mohammadpoor-Baltork, Iraj; Khosropour, Ahmad Reza; Zakeri, Maryam

    2012-01-01

    Efficient epoxidation of olefins catalyzed by MoO 2 (acac) 2 supported on amines functionalized MWCNTs is reported. The MWCNTs bearing carboxylic acid groups were modified with 2-aminophenol and 2-aminothiophenol. These amine–MWCNTs act as bidentate ligand for attachment of Mo catalyst. These catalysts were characterized by elemental analysis, scanning electron microscopy, FT-IR and diffuse reflectance UV–Vis spectroscopic methods. The prepared catalysts were used for efficient epoxidation of different alkenes such as cyclic and linear ones with tert-butyl hydroperoxide in refluxing 1,2-dichloroethane. These heterogeneous catalysts can be reused several times without significant loss of their catalytic activity. Highlights: ► Supporting of molybdenyl acetylacetonate on amine-modified MWCNTs. ► Heterogeneous catalysts were prepared. ► These catalysts were highly efficient in the epoxidation of alkenes with TBHP. ► Makes the catalysts reusable.

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

    KAUST Repository

    Yates, Matthew D.; Logan, Bruce E.

    2014-01-01

    © 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. 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.

  18. Method of preparing Ru-immobilized polymer-supported catalyst for hydrogen generation from NaBH{sub 4} solution

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Ching-Wen; Chen, Chuh-Yung; Huang, Yao-Hui [Department of Chemical Engineering, National Cheng Kung University, No.1, University Road, Tainan City 70101 (China)

    2009-03-15

    A method of preparing a polymer-supported catalyst for hydrogen generation is introduced in this article. This polymer-supported catalyst is the structure of ruthenium (Ru) nanoparticle immobilized on a monodisperse polystyrene (PSt) microsphere. The diameter of the Ru nanoparticle is around 16 nm, and the diameter of the PSt microsphere is 2.65 um. This preparation method is accomplished by two unique techniques: one is sodium lauryl sulfate/sodium formaldehyde sulfoxylate (SLS/SFS) interface-initiated system, the other is 2-methacrylic acid 3-(bis-carboxymethylamino)-2-hydroxy-propyl ester (GMA-IDA) chelating monomer. By taking advantage of these two techniques, Ru{sup 3+} ion will be chelated and then reduced to Ru{sup (0)} nanoparticle over PSt surface predominantly. The hydrolysis of alkaline sodium borohydride (NaBH{sub 4}) solution catalyzed by this Ru-immobilized polymer-supported catalyst is also examined in this article. It reveals that the hydrogen generation rate is 215.9 ml/min g-cat. in a diluted solution containing 1 wt.% NaBH{sub 4} and 1 wt.% NaOH, and this Ru-immobilized polymer-supported catalyst could be recycled during the reaction. (author)

  19. Preparation, surface characterization and performance of a Fischer-Tropsch catalyst of cobalt supported on silica nanosprings

    Energy Technology Data Exchange (ETDEWEB)

    Kengne, Blaise-Alexis Fouetio [Department of Physics, University of Idaho, Moscow, ID 83844-0903 (United States); Alayat, Abdulbaset M. [Environmental Science Program, University of Idaho, Moscow, ID 83844-3006 (United States); Luo, Guanqun [Department of Forest, Rangeland & Fire Sciences, University of Idaho, Moscow, ID 83844-1132 (United States); McDonald, Armando G. [Environmental Science Program, University of Idaho, Moscow, ID 83844-3006 (United States); Department of Forest, Rangeland & Fire Sciences, University of Idaho, Moscow, ID 83844-1132 (United States); Brown, Justin; Smotherman, Hayden [Department of Physics, University of Idaho, Moscow, ID 83844-0903 (United States); McIlroy, David N., E-mail: dmcilroy@uidaho.edu [Department of Physics, University of Idaho, Moscow, ID 83844-0903 (United States)

    2015-12-30

    Graphical abstract: - Highlights: • Determined that the reduction of Co nanoparticles on silica nanosprings 200 °C higher than the reduction temperature of Co in a solgel support. • The high reduction temperature of Co supported on silica nanosprings is attributed to the heat transfer properties of the nanosprings due to their high surface area. Co-silica nanospring Fischer-Tropsch catalyst can be used to produce drop in fuels such as JP-4. - Abstract: The reduction of cobalt (Co) catalyst supported on silica nanosprings for Fischer-Tropsch synthesis (FTS) has been monitored by X-ray photoelectron spectroscopy (XPS) and compared to FT catalytic activity. The cobalt is present in the starting catalyst as a Co{sub 3}O{sub 4} spinel phase. A two-step reduction of Co{sub 3}O{sub 4} to CoO and then to Co{sup 0} is observed, which is consistent with the results of H{sub 2}-temperature programmed reduction. During the reduction the two steps occur concurrently. The deconvolution of the Co 2p core level state for the catalyst reduced at 385 °C and 1.0 × 10{sup −6} Torr of H{sub 2} revealed signatures of Co{sup 0}, CoO, and Co{sub 3}O{sub 4}. The reduction saturates at a Co{sup o} concentration of approximately 41% after 20 h, which correlates with the activity and lifetime of the catalyst during FTS testing. Conversely, at 680 °C and 10 Torr of H{sub 2}, the catalyst is completely reduced after 10 h. The evolution of the Co d-band at the Fermi level in the valence band XPS spectrum definitively verifies the metallic phase of Co. FTS evaluation of the Co/NS catalyst reduced at 609 °C showed higher production rate (3-fold) of C{sub 6}-C{sub 17} hydrocarbons than the catalyst reduced at 409 °C and is consistent with the XPS analysis.

  20. Comparison study of catalyst nanoparticle formation and carbon nanotube growth: Support effect

    International Nuclear Information System (INIS)

    Wang Yunyu; Luo Zhiquan; Li Bin; Ho, Paul S.; Yao Zhen; Shi Li; Bryan, Eugene N.; Nemanich, Robert J.

    2007-01-01

    A comparison study has been conducted on the formation of catalyst nanoparticles on a high surface tension metal and low surface tension oxide for carbon nanotube (CNT) growth via catalytic chemical vapor deposition (CCVD). Silicon dioxide (SiO 2 ) and tantalum have been deposited as supporting layers before deposition of a thin layer of iron catalyst. Iron nanoparticles were formed after thermal annealing. It was found that densities, size distributions, and morphologies of iron nanoparticles were distinctly different on the two supporting layers. In particular, iron nanoparticles revealed a Volmer-Weber growth mode on SiO 2 and a Stranski-Krastanov mode on tantalum. CCVD growth of CNTs was conducted on iron/tantalum and iron/SiO 2 . CNT growth on SiO 2 exhibited a tip growth mode with a slow growth rate of less than 100 nm/min. In contrast, the growth on tantalum followed a base growth mode with a fast growth rate exceeding 1 μm/min. For comparison, plasma enhanced CVD was also employed for CNT growth on SiO 2 and showed a base growth mode with a growth rate greater than 2 μm/min. The enhanced CNT growth rate on tantalum was attributed to the morphologies of iron nanoparticles in combination with the presence of an iron wetting layer. The CNT growth mode was affected by the adhesion between the catalyst and support as well as CVD process

  1. Carbon-Supported Fe Catalysts for CO2 Electroreduction to High-Added Value Products: A DEMS Study: Effect of the Functionalization of the Support

    OpenAIRE

    Pérez-Rodríguez, S.; García, G.; Calvillo, L.; Celorrio, V.; Pastor, E.; Lázaro, M. J.

    2011-01-01

    Vulcan XC-72R-supported Fe catalysts have been synthesised for the electroreduction of CO2 to high-added value products. Catalysts were obtained by the polyol method, using ethylene glycol as solvent and reducing agent. Prior to the metal deposition, Vulcan was subjected to different oxidation treatments in order to modify its surface chemistry and study its influence on the physicochemical and electrochemical properties of the catalysts, as well as on the product distribution. The oxidation ...

  2. Hydrodeoxygenation and coupling of aqueous phenolics over bifunctional zeolite-supported metal catalysts.

    Science.gov (United States)

    Hong, Do-Young; Miller, Stephen J; Agrawal, Pradeep K; Jones, Christopher W

    2010-02-21

    Pt supported on HY zeolite is successfully used as a bifunctional catalyst for phenol hydrodeoxygenation in a fixed-bed configuration at elevated hydrogen pressures, leading to hydrogenation-hydrogenolysis ring-coupling reactions producing hydrocarbons, some with enhanced molecular weight.

  3. Phosphate-Doped Carbon Black as Pt Catalyst Support: Co-catalytic Functionality for Dimethyl Ether and Methanol Electro-oxidation

    DEFF Research Database (Denmark)

    Yin, Min; Huang, Yunjie; Li, Qingfeng

    2014-01-01

    ). The supported Pt catalysts show significant improvement in catalytic activity towards the direct oxidation of methanol and DME, attributable to the enhanced adsorption and dehydrogenation of methanol and DME, as well as the presence of activated OH species in the catalysts. The latter is demonstrated......Niobium-phosphate-doped (NbP-doped) carbon blacks were prepared as the composite catalyst support for Pt nanoparticles. Functionalities of the composite include intrinsic proton conductivity, surface acidity, and interfacial synergistic interactions with methanol and dimethyl ether (DME...... to facilitate the removal of CO intermediates formed during the oxidation reactions....

  4. Ruthenium-platinum bimetallic catalysts supported on silica: characterization and study of benzene hydrogenation and CO methanation

    Energy Technology Data Exchange (ETDEWEB)

    Chakrabarty, D.K.; Rao, K.M.; Sundararaman, N.; Chandavar, K.

    1986-12-15

    Ru-Pt/SiO/sub 2/ bimetallic catalysts with varying Ru:Pt ratio have been prepared and studied with the aim to establish if they contain coclusters or isolated ruthenium and platinum particles. X-ray diffraction studies show that individual crystallites of ruthenium and platinum are present and no coclusters are formed. Metal dispersion has been determined by hydrogen chemisorption and surface composition of the catalysts has been obtained from XPS. It was found that preoxidation of the catalysts prior to reduction is essential for good platinum dispersion. The experimental turnover number (TN) for benzene hydrogenation on the bimetallic catalysts agrees very well with that of the weighted average on the individual metal catalysts and this may be taken as a kinetic evidence for the absence of coclusters. Carbon monoxide methanation activity of the bimetallic catalysts is quite similar to that of the supported platinum catalyst. 6 refs., 6 figs., 2 tabs.

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

    Czech Academy of Sciences Publication Activity Database

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

    2013-01-01

    Roč. 265, JAN 15 (2013), s. 309-313 ISSN 0169-4332 Institutional support: RVO:67985858 Keywords : nano-structured TiO2 * NiW catalysts * XPS Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 2.538, year: 2013

  6. 4,6-Dimethyl-dibenzothiophene conversion over Al{sub 2}O{sub 3}-TiO{sub 2}-supported noble metal catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Nunez, Sara [Departamento de Ingenieria de Procesos e Hidraulica, Universidad Autonoma Metropolitana-Iztapalapa, San Rafael Atlixco 186, Vicentina, Iztapalapa, 09340, Mexico, D.F. (Mexico); Escobar, Jose, E-mail: jeaguila@imp.mx [Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas 152, San Bartolo Atepehuacan, Gustavo A. Madero, 07730, Mexico, D.F. (Mexico); Vazquez, Armando; Reyes, Jose Antonio de los [Departamento de Ingenieria de Procesos e Hidraulica, Universidad Autonoma Metropolitana-Iztapalapa, San Rafael Atlixco 186, Vicentina, Iztapalapa, 09340, Mexico, D.F. (Mexico); Hernandez-Barrera, Melissa [Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas 152, San Bartolo Atepehuacan, Gustavo A. Madero, 07730, Mexico, D.F. (Mexico)

    2011-03-15

    Research highlights: {yields} Al{sub 2}O{sub 3} and Al{sub 2}O{sub 3}-TiO{sub 2} (molar ratio Al/Ti = 2, AT2) mixed oxides were pore-filling impregnated to obtain Pd, Pt and Pd-Pt catalysts with {approx}1 wt% nominal metal loading. {yields} Reduced catalysts were tested in the 4,6-dimethyl-dibenzothiophene hydrodesulfurization (HDS). {yields} In Pd-containing materials, TiO{sub 2} incorporation into the alumina support was favorable to the catalytic activity of noble metal catalysts. {yields} Enhanced intrinsic activity (per exposed metallic site) was obtained in Pt-containing catalysts supported on the AT2 mixed oxide. {yields} Yield to different products over various catalysts seemed to be strongly influenced by metallic particles dispersion. - Abstract: Al{sub 2}O{sub 3} and Al{sub 2}O{sub 3}-TiO{sub 2} (molar ratio Al/Ti = 2, AT2) mixed oxides were synthesized using a low-temperature sol-gel method and were further pore-filling impregnated to obtain Pd and Pt catalysts with {approx}1 wt% nominal metal loading. Simultaneous impregnation was used to prepare bimetallic materials at Pd:Pt = 80:20. Solids characterization was carried out by N{sub 2}-physisorption, high-resolution transmission electron microscopy (HR-TEM and E-FTEM), X-ray diffraction, temperature-programmed reduction and CO-chemisorption. Reduced (350 deg. C, H{sub 2} flow) catalysts were tested in the 4,6-dimethyl-dibenzothiophene hydrodesulfurization (HDS) (in n-dodecane, at 300 deg. C and 5.5 MPa, batch reactor). In Pd-containing materials, TiO{sub 2} incorporation into the alumina support was favorable to the catalytic activity of noble metal catalysts, where bimetallic Pd-Pt with AT2 carrier had the highest organo-S compound conversion. Enhanced intrinsic activity (per exposed metallic site) was obtained in Pt-containing catalysts supported on the AT2 mixed oxide (as compared to alumina-supported ones). Yield to different products over various catalysts seemed to be strongly influenced by

  7. Polystyrene-supported pyridinium chloroaluminate ionic liquid as a new heterogeneous Lewis acid catalyst for selective synthesis of benzimidazoles

    Directory of Open Access Journals (Sweden)

    Parvanak Boroujeni Kaveh

    2013-01-01

    Full Text Available Polystyrene-supported pyridinium chloroaluminate ionic liquid was prepared from the reaction of Merrifield resin with pyridine followed by reaction with aluminium chloride. This catalyst was used as a new chemoselective Lewis acid catalyst for the exclusive synthesis of 2-substituted benzimidazoles from the reaction of aldehydes with o-phenylenediamines. The catalyst is stable (as a bench top catalyst and can be easily recovered and reused without appreciable change in its efficiency.

  8. Thermally oxidized aluminum as catalyst-support layer for vertically aligned single-walled carbon nanotube growth using ethanol

    Energy Technology Data Exchange (ETDEWEB)

    Azam, Mohd Asyadi, E-mail: asyadi@jaist.ac.jp [School of Materials Science, Japan Advanced Institute of Science and Technology (JAIST), 1-1 Asahidai, Nomi, Ishikawa 923-1292 (Japan); Fujiwara, Akihiko [Research and Utilization Division, Japan Synchrotron Radiation Research Institute (JASRI), 1-1-1, Kouto, Sayo-cho, Sayo, Hyogo 679-5198 (Japan); Shimoda, Tatsuya [School of Materials Science, Japan Advanced Institute of Science and Technology (JAIST), 1-1 Asahidai, Nomi, Ishikawa 923-1292 (Japan)

    2011-11-01

    Characteristics and role of Al oxide (Al-O) films used as catalyst-support layer for vertical growth of single-walled carbon nanotubes (SWCNTs) were studied. EB-deposited Al films (20 nm) were thermally oxidized at 400 deg. C (10 min, static air) to produce the most appropriate surface structure of Al-O. Al-O catalyst-support layers were characterized using various analytical measurements, i.e., atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and spectroscopy ellipsometry (SE). The thermally oxidized Al-O has a highly roughened surface, and also has the most suitable surface chemical states compared to other type of Al-O support layers. We suggest that the surface of thermally oxidized Al-O characterized in this work enhanced Co catalyst activity to promote the vertically aligned SWCNT growth.

  9. Multi-wall carbon nanotubes supported molybdenyl acetylacetonate: Efficient and highly reusable catalysts for epoxidation of alkenes with tert-butyl hydroperoxide

    Energy Technology Data Exchange (ETDEWEB)

    Esnaashari, Fariba [Department of Chemistry, Catalysis Division, University of Isfahan, Isfahan 81746-73441 (Iran, Islamic Republic of); Moghadam, Majid, E-mail: moghadamm@sci.ui.ac.ir [Department of Chemistry, Catalysis Division, University of Isfahan, Isfahan 81746-73441 (Iran, Islamic Republic of); Mirkhani, Valiollah, E-mail: mirkhani@sci.ui.ac.ir [Department of Chemistry, Catalysis Division, University of Isfahan, Isfahan 81746-73441 (Iran, Islamic Republic of); Tangestaninejad, Shahram; Mohammadpoor-Baltork, Iraj; Khosropour, Ahmad Reza; Zakeri, Maryam [Department of Chemistry, Catalysis Division, University of Isfahan, Isfahan 81746-73441 (Iran, Islamic Republic of)

    2012-11-15

    Efficient epoxidation of olefins catalyzed by MoO{sub 2}(acac){sub 2} supported on amines functionalized MWCNTs is reported. The MWCNTs bearing carboxylic acid groups were modified with 2-aminophenol and 2-aminothiophenol. These amine-MWCNTs act as bidentate ligand for attachment of Mo catalyst. These catalysts were characterized by elemental analysis, scanning electron microscopy, FT-IR and diffuse reflectance UV-Vis spectroscopic methods. The prepared catalysts were used for efficient epoxidation of different alkenes such as cyclic and linear ones with tert-butyl hydroperoxide in refluxing 1,2-dichloroethane. These heterogeneous catalysts can be reused several times without significant loss of their catalytic activity. Highlights: Black-Right-Pointing-Pointer Supporting of molybdenyl acetylacetonate on amine-modified MWCNTs. Black-Right-Pointing-Pointer Heterogeneous catalysts were prepared. Black-Right-Pointing-Pointer These catalysts were highly efficient in the epoxidation of alkenes with TBHP. Black-Right-Pointing-Pointer Makes the catalysts reusable.

  10. Silica-supported (nBuCp)2ZrCl2: Effect of catalyst active center distribution on ethylene-1-hexene copolymerization

    KAUST Repository

    Atiqullah, Muhammad

    2013-08-12

    Metallocenes are a modern innovation in polyolefin catalysis research. Therefore, two supported metallocene catalysts-silica/MAO/(nBuCp)2ZrCl2 (Catalyst 1) and silica/nBuSnCl3/MAO/(nBuCp)2ZrCl2 (Catalyst 2), where MAO is methylaluminoxane-were synthesized, and subsequently used to prepare, without separate feeding of MAO, ethylene-1-hexene Copolymer 1 and Copolymer 2, respectively. Fouling-free copolymerization, catalyst kinetic stability and production of free-flowing polymer particles (replicating the catalyst particle size distribution) confirmed the occurrence of heterogeneous catalysis. The catalyst active center distribution was modeled by deconvoluting the measured molecular weight distribution and copolymer composition distribution. Five different active center types were predicted for each catalyst, which was corroborated by successive self-nucleation and annealing experiments, as well as by an extended X-ray absorption fine structure spectroscopy report published in the literature. Hence, metallocenes impregnated particularly on an MAO-pretreated support may be rightly envisioned to comprise an ensemble of isolated single sites that have varying coordination environments. This study shows how the active center distribution and the design of supported MAO anions affect copolymerization activity, polymerization mechanism and the resulting polymer microstructures. Catalyst 2 showed less copolymerization activity than Catalyst 1. Strong chain transfer and positive co-monomer effect-both by 1-hexene-were common. Each copolymer demonstrated vinyl, vinylidene and trans-vinylene end groups, and compositional heterogeneity. All these findings were explained, as appropriate, considering the modeled active center distribution, MAO cage structure repeat units, proposed catalyst surface chemistry, segregation effects and the literature that concerns and supports this study. While doing so, new insights were obtained. Additionally, future research, along the direction

  11. Silica-supported (nBuCp)2ZrCl2: Effect of catalyst active center distribution on ethylene-1-hexene copolymerization

    KAUST Repository

    Atiqullah, Muhammad; Anantawaraskul, Siripon; Emwas, Abdul-Hamid M.; Al-Harthi, Mamdouh Ahmed; Hussain, Ikram; Ul-Hamid, Anwar; Hossaen, Anwar

    2013-01-01

    Metallocenes are a modern innovation in polyolefin catalysis research. Therefore, two supported metallocene catalysts-silica/MAO/(nBuCp)2ZrCl2 (Catalyst 1) and silica/nBuSnCl3/MAO/(nBuCp)2ZrCl2 (Catalyst 2), where MAO is methylaluminoxane-were synthesized, and subsequently used to prepare, without separate feeding of MAO, ethylene-1-hexene Copolymer 1 and Copolymer 2, respectively. Fouling-free copolymerization, catalyst kinetic stability and production of free-flowing polymer particles (replicating the catalyst particle size distribution) confirmed the occurrence of heterogeneous catalysis. The catalyst active center distribution was modeled by deconvoluting the measured molecular weight distribution and copolymer composition distribution. Five different active center types were predicted for each catalyst, which was corroborated by successive self-nucleation and annealing experiments, as well as by an extended X-ray absorption fine structure spectroscopy report published in the literature. Hence, metallocenes impregnated particularly on an MAO-pretreated support may be rightly envisioned to comprise an ensemble of isolated single sites that have varying coordination environments. This study shows how the active center distribution and the design of supported MAO anions affect copolymerization activity, polymerization mechanism and the resulting polymer microstructures. Catalyst 2 showed less copolymerization activity than Catalyst 1. Strong chain transfer and positive co-monomer effect-both by 1-hexene-were common. Each copolymer demonstrated vinyl, vinylidene and trans-vinylene end groups, and compositional heterogeneity. All these findings were explained, as appropriate, considering the modeled active center distribution, MAO cage structure repeat units, proposed catalyst surface chemistry, segregation effects and the literature that concerns and supports this study. While doing so, new insights were obtained. Additionally, future research, along the direction

  12. Electron Tomography Reveals the Active Phase–Support Interaction in Sulfidic Hydroprocessing Catalysts

    NARCIS (Netherlands)

    Eijsbouts, Sonja; Li, Xuang; Juan-Alcaniz, Jana; van den Oetelaar, Leon C A; Bergwerff, Jaap; Loos, Joachim; Carlsson, Anna; Vogt, E.T.C.

    2017-01-01

    Conventional two-dimensional (2D) transmission electron microscopy of sulfidic hydroprocessing catalysts can be deceiving and give the impression that parts of the support are overloaded with active phase. High-angle annular dark field scanning transmission electron microscopy tomography reveals

  13. Studies of Immobilized Homogeneous Metal Catalysts on Silica Supports

    Energy Technology Data Exchange (ETDEWEB)

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

    2003-01-01

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

  14. 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.

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

    Indian Academy of Sciences (India)

    4. Conclusion. A novel multicomponent approach for the synthesis of a series of new acenaphthofuran derivatives utilizing the supported ionic liquid catalyst has been elaborated. The efficient catalysing of used ionic liquid in the synthesis of acenaphtho[1,2-b]furans led to high chemical yields as well as short reaction times.

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

    DEFF Research Database (Denmark)

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

    2014-01-01

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

  17. ALKALI RESISTANT CATALYST

    DEFF Research Database (Denmark)

    2008-01-01

    The present invention concerns the selective removal of nitrogen oxides (NOx) from gasses. In particular, the invention concerns a process, a catalyst and the use of a catalyst for the selective removal of nitrogen oxides in the presence of ammonia from gases containing a significant amount...... of alkali metal and/or alkali-earth compounds which process comprises using a catalyst combined of (i) a formed porous superacidic support, said superacidic support having an Hammett acidity stronger than Ho=-12, and (ii) a metal oxide catalytic component deposited on said superacidic support selected from...

  18. Recent progress in solution plasma-synthesized-carbon-supported catalysts for energy conversion systems

    Science.gov (United States)

    Lun Li, Oi; Lee, Hoonseung; Ishizaki, Takahiro

    2018-01-01

    Carbon-based materials have been widely utilized as the electrode materials in energy conversion and storage technologies, such as fuel cells and metal-air batteries. In these systems, the oxygen reduction reaction is an important step that determines the overall performance. A novel synthesis route, named the solution plasma process, has been recently utilized to synthesize various types of metal-based and heteroatom-doped carbon catalysts. In this review, we summarize cutting-edge technologies involving the synthesis and modeling of carbon-supported catalysts synthesized via solution plasma process, followed by current progress on the electrocatalytic performance of these catalysts. This review provides the fundamental and state-of-the-art performance of solution-plasma-synthesized electrode materials, as well as the remaining scientific and technological challenges for this process.

  19. Propene and l-octene hydroformylation with silica-supported, ionic liquid-phase (SILP) Rh-phosphine catalysts in continuous fixed-bed mode

    DEFF Research Database (Denmark)

    Riisager, Anders; Eriksen, Kim Michael; Wasserscheid, Peter

    2003-01-01

    - and liquid-phase hydroformylation of propene and 1-octene, exhibiting TOFs up to 88 h(-1) for SILP Rh-2 catalysts, while only low selectivities up to 74% n-aldehyde (n/iso ratio of 2.8) were obtained. This is the first example of continuous fixed-bed liquid-phase hydroformylation using SILP catalysts.......Supported ionic liquid-phase (SILP) catalysts were made by immobilizing Rh-monophosphine complexes of bis(m-phenylguanidinium) phenylphosphine 1 and NORBOS 2 ligands in 1-n-butyl-3-methylimidazolium hexafluorophosphate, [BMIM] [PF6], on a silica support. The catalysts were active in continuous gas...

  20. Hydrodeoxygenation of bio-oil using different mesoporous supports of NiMo catalysts

    Science.gov (United States)

    Rinaldi, Nino; Simanungkalit, Sabar P.; Kristiani, Anis

    2017-11-01

    Biomass as a renewable and sustainable resources need to utilize in many applications, especially for energy application. One of its energy application is about converting biomass into bio-oil. High oxygen content in bio-oil needs to be upgraded through hydrodeoxygenation process before being used as transportation fuel. The development of heterogenenous catalysts become an important aspect in hydrodeoxygenation process, in particular the upgrading process of bio-oil. Several supporting mesoporous materials, such as TiO2, Al2O3 and MCM-41 have unique properties, both physical and chemical properties that can be utilized in various application, including catalyst. These heterogeneous catalysts were modified their catalytic properties by impregnation with some transition metal. The effect of various supporting material and transition metal impregnated were also studied. Their chemical and physical properties were characterized by X-Ray Diffraction, X-Ray Fluororesence, Fourier Transform Infra-Red, and Surface Area Analyzer. The result of characterizations showed that Ni-Mo/TiO2 is more crystalline than Ni-Mo/MCM-41 and Ni-Mo/Al2O3. In other hand, the specific surface area of Ni-Mo/TiO2 is lower than others. These heterogeneous catalysts were tested their catalytic activity in upgrading bio-oil. The liquid products produced were analyzed by using Elemental Analyzer. The result of catalytic activity tests showed catalysts resulted Ni-Mo/TiO2 exhibits best catalytic activity in hydrodeoxygenation process. The oxygen content decreased significantly from 41.61% to 26.22% by using Ni-Mo/TiO2. Compared with Ni-Mo/TiO2, Ni-Mo/MCM-41 and Ni-Mo/Al2O3 decrease lower to 33.22% % and 28.34%, respectively. Ni-Mo/TiO2 also resulted the highest Deoxygenation Degree (DOD) as of 55% compared with Ni-Mo/MCM-41 and Ni-Mo/Al2O3 as of 31.99 % and 47.99%, respectively.

  1. 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...

  2. Manganese Dioxide Coated Graphene Nanoribbons Supported Palladium Nanoparticles as an Efficient Catalyst for Ethanol Electrooxidation in Alkaline Media

    International Nuclear Information System (INIS)

    Liu, Qi; Jiang, Kun; Fan, Jinchen; Lin, Yan; Min, Yulin; Xu, Qunjie; Cai, Wen-Bin

    2016-01-01

    Design of appropriate supporting materials is an alternative route to yield efficient Pt-free catalysts for ethanol oxidation reaction, which in practice may determine the conversion efficiency of direct alkaline ethanol fuel cells. In this work, graphene nanoribbons (GNRs) coated with MnO_2 are used as a unique supporting material for loading and dispersing Pd nanoparticles. XRD, TEM and XPS are applied to characterize the structure of as-synthesized Pd/MnO_2/GNRs nanocomposite catalyst, revealing a good dispersion as well as a modification of electronic property of Pd nanoparticles. Electrochemical measurements demonstrate that the as-synthesized nanocomposite displays largely enhanced electrocatalytic activity and durability toward ethanol oxidation in alkaline media as compared to the other tested Pd-based catalysts with various supports.

  3. Study on the influence of nickel and Al{sub 2}O{sub 3} support on MoS{sub 2} as hydrodenitrogenation catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Hein, J.; Hrabar, A.; Gutierrez, O.Y.; Lercher, J.A. [Technische Univ. Muenchen, Garching (Germany). Catalysis Research Center

    2012-07-01

    Alumina-supported Mo and Ni-Mo catalysts as well as an unsupported NiMo catalyst were characterized and tested in the hydrodenitrogenation (HDN) of quinoline in the presence of dibenzothiophene (DBT). The supported catalysts had a well dispersed MoS{sub 2} phase with an average stacking degree around two and slabs length below 10 nm. The unsupported NiMo sulfide catalyst exhibited long, multistacked MoS{sub 2} slabs and contained segregated Ni{sub x}S{sub y} phases. The formation of the Ni-Mo-S phase in both Ni containing catalysts was verified by X-ray absorption spectroscopy, whereas the concentration of coordinatively unsaturated sites was higher for the supported Mo and Ni-Mo catalysts than for the unsupported one. All catalysts were active in the HDN of quinoline and hydrodesulfurization of DBT. The catalytic activity increased in the order Mo/Al{sub 2}O{sub 3} < NiMo/unsupported < Ni-Mo/Al{sub 2}O{sub 3}. Thus, the influence on the catalytic activity of the promoter metal Ni is more important than the presence of a support due to the formation of the Ni-Mo-S phase (more active than MoS{sub 2}). (orig.)

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

    Directory of Open Access Journals (Sweden)

    J. F. Bozeman

    2011-01-01

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

  5. Hydroprocessing catalyst development

    Energy Technology Data Exchange (ETDEWEB)

    Boorman, P.M.; Kydd, R.A.; Sorensen, T.S.; Chong, K.; Lewis, J.

    1992-08-01

    Co-Mo and Ni-Mo hydroprocessing catalysts were examined for their activity in removal of sulfur from thiophene in model compounds, and in the cracking and hydrocracking of cumene. Three types of support materials were examined: carbon, modified carbon, and carbon covered alumina. The objective of the study was to examine the correlation between catalyst activity in the hydrodenitrogenation of model compounds, and the resistance of the catalyst to nitrogen poisoning during use in the hydroprocessing of gas oils. The use of model compound testing provided information on the individual catalytic reactions promoted by those materials. Infrared spectroscopy was used to study surface species on the catalysts and to explain many of the trends in activity observed, revealing the role of fluoride and phosphorus as a secondary promoter. Testing of the catalysts in hydrotreating of gas oils allowed comparison of model compound results with those from a real feedstock. The gas oil was also spiked with a model nitrogen compound and the results from catalytic hydrotreating of this material were compared with those from unspiked material. A key finding was that the carbon supported catalysts were the most effective in treating high-nitrogen feeds. The very favorable deactivation properties of carbon and carbon-covered alumina supported catalysts make these promising from an industrial point of view where catalyst deactivation is a limiting factor. 171 refs., 25 figs., 43 tabs.

  6. Crumpled rGO-supported Pt-Ir bifunctional catalyst prepared by spray pyrolysis for unitized regenerative fuel cells

    Science.gov (United States)

    Kim, In Gyeom; Nah, In Wook; Oh, In-Hwan; Park, Sehkyu

    2017-10-01

    Three-dimensional (3D) crumpled reduced graphene oxide supported Pt-Ir alloys that served as bifunctional oxygen catalysts for use in untized regenerative fuel cells were synthesized by a facile spray pyrolysis method. Pt-Ir catalysts supported on rGO (Pt-Ir/rGOs) were physically characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and thermogravimetric analysis (TGA) to observe change in composition by heat treatment, alloying, and morphological transition of the catalysts. Their catalytic activities and stabilities for the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) conditions were electrochemically investigated using cyclic voltammetry (CV), linear sweep voltammetry (LSV), potential cycling and hold tests on the rotating disk electrode (RDE). Pt-Ir/rGO with no post heat-treatment (Pt-Ir/rGO_NP) showed a lower activity for ORR and OER although metal nanoparticles decorated on the support are relatively small. However, Pt-Ir/rGO showed remarkably enhanced activity following heat treatment, depending on temperature. Pt-Ir/rGO heat-treated at 600 °C after spray pyrolysis (Pt-Ir/rGO_P600) exhibited a higher activity and stability than a commercially available Pt/C catalyst kept under the ORR condition, and it also revealed a comparable OER activity and durability versus the commercial unsupported Ir catalyst.

  7. Synthesis and Characterization of Polyethylene/Starch Nanocomposites: A Spherical Starch-Supported Catalyst and In Situ Ethylene Polymerization.

    Science.gov (United States)

    Zhanga, Hao; Xi, Shixia; Wang, Shuwei; Liu, Jingsheng; Yoon, Keun-Byoung; Lee, Dong-Ho; Zhang, Hexin; Zhang, Xuequan

    2017-01-01

    In the present article, a novel spherical starch-supported vanadium (V)-based Ziegler-Natta catalyst was synthesized. The active centers of the obtained catalyst well dispersed in the starch through the SEM-EDX analysis. The effects of reaction conditions on ethylene polymerization were studied. The synthesized catalyst exhibited high activity toward ethylene polymerization in the presence of ethylaluminium sesquichloride (EASC) cocatalyst. Interestingly, the fiber shape PE was obtained directly during the polymerization process.

  8. Effect of Al content on the gas-phase dehydration of glycerol over silica-alumina-supported silicotungstic acid catalysts

    International Nuclear Information System (INIS)

    Kim, Yong Tae; You, Su Jin; Park, Eun Duck; Jung, Kwangdeog

    2012-01-01

    The gas-phase dehydration of glycerol to acrolein was carried out over silicotungstic acid (H 4 SiW 12 O 40 ·xH 2 O, HSiW) catalysts supported on SiO 2 , η-Al 2 O 3 , and silica-alumina with different Al contents. The HSiW catalysts supported on silica-alumina showed higher glycerol conversions and acrolein yields during the initial 2 h at 315.deg.C than did SiO 2 - and η-Al 2 O 3 -supported HSiW catalysts. Among the tested catalysts, HSiW/Si 0.9 Al 0.1Ox exhibited the highest space-time yield during the initial 2 h. The loaded HSiW species can change the acid types and suppress the formation of carbonaceous species on Al-rich silica-alumina. The deactivated HSiW supported on silica-alumina can be fully regenerated after calcination in air at 500.deg.C. As long as the molar ratio between water and glycerol was in the range of 2-11, the acrolein selectivity increased significantly with increasing water content in the feed, while the surface carbon content decreased owing to the suppression of heavy compounds

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

    KAUST Repository

    Huang, Kuo-Wei

    2017-11-23

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

  10. Influences of species of metals and supports on the hydrogenation activity of carbon-supported metal sulfides catalysts; Tanso biryushi tanji shokubai no suisoka kassei ni taisuru kassei kinzoku oyobi tantaishu no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Sakanishi, K.; Hasuo, H.; Taniguchi, H.; Nagamatsu, T.; Mochida, I. [Kyushu University, Fukuoka (Japan). Institute of Advanced Material Study

    1996-10-28

    In order to design catalysts suitable for primary liquefaction stage and secondary upgrading stage respectively in the multi-stage liquefaction process, various carbon-supported catalysts were prepared. Catalytic activities of them were investigated for the hydrogenation of 1-methylnaphthalene, to discuss the influences of metals and carbon species on the catalytic activity. Various water soluble and oil soluble Mo and Ni salts were used for NiMo supported catalysts. Among various carbon supports, Ketjen Black (KB) was effective for preparing the catalyst showing the most excellent hydrogenation activity. The KB and Black Pearl 2000 (BP2000) showing high hydrogenation activity were fine particles having high specific surface area more than 1000 m{sup 2}/g and primary particle diameter around 30 nm. This was inferred to contribute to the high dispersion support of active metals. Since such fine particles of carbon exhibited hydrophobic surface, they were suitable for preparing catalysts from the methanol-soluble metals. Although Ni and Mo added iron-based catalysts provided lower aromatic hydrogenation activity, they exhibited liquefaction activity competing with the NiMo/KB catalyst. 3 refs., 1 fig., 3 tabs.

  11. Reducible oxide based catalysts

    Science.gov (United States)

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

    2010-04-06

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

  12. Carbon-Supported Pd and PdFe Alloy Catalysts for Direct Methanol Fuel Cell Cathodes

    Directory of Open Access Journals (Sweden)

    Luis M. Rivera Gavidia

    2017-05-01

    Full Text Available Direct methanol fuel cells (DMFCs are electrochemical devices that efficiently produce electricity and are characterized by a large flexibility for portable applications and high energy density. Methanol crossover is one of the main obstacles for DMFC commercialization, forcing the search for highly electro-active and methanol tolerant cathodes. In the present work, carbon-supported Pd and PdFe catalysts were synthesized using a sodium borohydride reduction method and physico-chemically characterized using transmission electron microscopy (TEM and X-ray techniques such as photoelectron spectroscopy (XPS, diffraction (XRD and energy dispersive spectroscopy (EDX. The catalysts were investigated as DMFC cathodes operating at different methanol concentrations (up to 10 M and temperatures (60 °C and 90 °C. The cell based on PdFe/C cathode presented the best performance, achieving a maximum power density of 37.5 mW·cm−2 at 90 °C with 10 M methanol, higher than supported Pd and Pt commercial catalysts, demonstrating that Fe addition yields structural changes to Pd crystal lattice that reduce the crossover effects in DMFC operation.

  13. A Novel Synthesis of Gold Nanoparticles Supported on Hybrid Polymer/Metal Oxide as Catalysts for p-Chloronitrobenzene Hydrogenation

    Directory of Open Access Journals (Sweden)

    Cristian H. Campos

    2017-01-01

    Full Text Available This contribution reports a novel preparation of gold nanoparticles on polymer/metal oxide hybrid materials (Au/P[VBTACl]-M metal: Al, Ti or Zr and their use as heterogeneous catalysts in liquid phase hydrogenation of p-chloronitrobenzene. The support was prepared by in situ radical polymerization/sol gel process of (4-vinyl-benzyltrimethylammonium chloride and 3-(trimethoxysilylpropyl methacrylate in conjunction with metal-alkoxides as metal oxide precursors. The supported catalyst was prepared by an ion exchange process using chloroauric acid (HAuCl4 as gold precursor. The support provided the appropriate environment to induce the spontaneous reduction and deposition of gold nanoparticles. The hybrid material was characterized. TEM and DRUV-vis results indicated that the gold forms spherical metallic nanoparticles and that their mean diameter increases in the sequence, Au/P[VBTACl]-Zr > Au/P[VBTACl]-Al > Au/P[VBTACl]-Ti. The reactivity of the Au catalysts toward the p-CNB hydrogenation reaction is attributed to the different particle size distributions of gold nanoparticles in the hybrid supports. The kinetic pseudo-first-order constant values for the catalysts in the hydrogenation reaction increases in the order, Au/P[VBTACl]-Al > Au/P[VBTACl]-Zr > Au/P[VBTACl]-Ti. The selectivity for all the catalytic systems was greater than 99% toward the chloroaniline target product. Finally the catalyst supported on the hybrid with Al as metal oxide could be reused at least four times without loss in activity or selectivity for the hydrogenation of p-CNB in ethanol as solvent.

  14. 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...

  15. Dehydration of xylose to furfural over MCM-41-supported niobium-oxide catalysts.

    Science.gov (United States)

    García-Sancho, Cristina; Sádaba, Irantzu; Moreno-Tost, Ramón; Mérida-Robles, Josefa; Santamaría-González, José; López-Granados, Manuel; Maireles-Torres, Pedro

    2013-04-01

    A series of silica-based MCM-41-supported niobium-oxide catalysts are prepared, characterized by using XRD, N2 adsorption-desorption, X-ray photoelectron spectroscopy, Raman spectroscopy, and pyridine adsorption coupled to FTIR spectroscopy, and tested for the dehydration of D-xylose to furfural. Under the operating conditions used all materials are active in the dehydration of xylose to furfural (excluding the MCM-41 silica support). The xylose conversion increases with increasing Nb2 O5 content. At a loading of 16 wt % Nb2 O5 , 74.5 % conversion and a furfural yield of 36.5 % is achieved at 170 °C, after 180 min reaction time. Moreover, xylose conversion and furfural yield increase with the reaction time and temperature, attaining 82.8 and 46.2 %, respectively, at 190 °C and after 100 min reaction time. Notably, the presence of NaCl in the reaction medium further increases the furfural yield (59.9 % at 170 °C after 180 min reaction time). Moreover, catalyst reutilization is demonstrated by performing at least three runs with no loss of catalytic activity and without the requirement for an intermediate regeneration step. No significant niobium leaching is observed, and a relationship between the structure of the catalyst and the activity is proposed. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Understanding the performance and mechanism of Mg-containing oxides as support catalysts in the thermal dry reforming of methane.

    Science.gov (United States)

    Khairudin, Nor Fazila; Sukri, Mohd Farid Fahmi; Khavarian, Mehrnoush; Mohamed, Abdul Rahman

    2018-01-01

    Dry reforming of methane (DRM) is one of the more promising methods for syngas (synthetic gas) production and co-utilization of methane and carbon dioxide, which are the main greenhouse gases. Magnesium is commonly applied in a Ni-based catalyst in DRM to improve catalyst performance and inhibit carbon deposition. The aim of this review is to gain better insight into recent developments on the use of Mg as a support or promoter for DRM catalysts. Its high basicity and high thermal stability make Mg suitable for introduction into the highly endothermic reaction of DRM. The introduction of Mg as a support or promoter for Ni-based catalysts allows for good metal dispersion on the catalyst surface, which consequently facilitates high catalytic activity and low catalyst deactivation. The mechanism of DRM and carbon formation and reduction are reviewed. This work further explores how different constraints, such as the synthesis method, metal loading, pretreatment, and operating conditions, influence the dry reforming reactions and product yields. In this review, different strategies for enhancing catalytic activity and the effect of metal dispersion on Mg-containing oxide catalysts are highlighted.

  17. A facile method for the preparation of Covalent Triazine Framework coated monoliths as catalyst support - applications in C1 catalysis

    KAUST Repository

    Bavykina, Anastasiya V.

    2017-07-17

    A quasi Chemical Vapour Deposition method for the manufacturing of well-defined Covalent Triazine Framework (CTF) coatings on cordierite monoliths is reported. The resulting supported porous organic polymer is an excellent support for the immobilisation of two different homogeneous catalysts: 1) an IrIIICp*-based catalyst for the hydrogen production from formic acid, and 2) a PtII-based for the direct activation of methane via Periana chemistry. The immobilised catalysts display a much higher activity in comparison with the unsupported CTF operated in slurry because of improved mass transport. Our results demonstrate that CTF based catalysts can be further optimised by engineering at different length-scales.

  18. A facile method for the preparation of Covalent Triazine Framework coated monoliths as catalyst support - applications in C1 catalysis

    KAUST Repository

    Bavykina, Anastasiya V.; Olivos Suarez, Alma Itzel; Osadchii, Dmitrii; Valecha, Rahul; Franz, Robert; Makkee, Michiel; Kapteijn, Freek; Gascon, Jorge

    2017-01-01

    A quasi Chemical Vapour Deposition method for the manufacturing of well-defined Covalent Triazine Framework (CTF) coatings on cordierite monoliths is reported. The resulting supported porous organic polymer is an excellent support for the immobilisation of two different homogeneous catalysts: 1) an IrIIICp*-based catalyst for the hydrogen production from formic acid, and 2) a PtII-based for the direct activation of methane via Periana chemistry. The immobilised catalysts display a much higher activity in comparison with the unsupported CTF operated in slurry because of improved mass transport. Our results demonstrate that CTF based catalysts can be further optimised by engineering at different length-scales.

  19. 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.

  20. Synthesis of Single-Walled Carbon Nanotubes: Effects of Active Metals, Catalyst Supports, and Metal Loading Percentage

    Directory of Open Access Journals (Sweden)

    Wei-Wen Liu

    2013-01-01

    Full Text Available The effects of active metals, catalyst supports, and metal loading percentage on the formation of single-walled carbon nanotubes (SWNTs were studied. In particular, iron, cobalt, and nickel were investigated for SWNTs synthesis. Iron was found to grow better-quality SWNTs compared to cobalt and nickel. To study the effect of catalyst supports, magnesium oxide, silicon oxide, and aluminium oxide were chosen for iron. Among the studied supports, MgO was identified to be a suitable support for iron as it produced SWNTs with better graphitisation determined by Raman analysis. Increasing the iron loading decreased the quality of SWNTs due to extensive agglomeration of the iron particles. Thus, lower metal loading percentage is preferred to grow better-quality SWNTs with uniform diameters.

  1. 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 activity......, BET surface area and pore morphology of the catalysts depended on the content of ionic liquid. Hence, catalysts with high ionic liquid loading content showed deactivation at high reaction temperatures, possibly caused by redistribution of ionic liquid out of the pores under these conditions. (C) 2012...

  2. Synthesis of Poly(3,4-Ethylenedioxy thiophene)-Poly(Styrene-4-Sulfonate) Composites for Support Fuel Cell Catalyst Layer

    International Nuclear Information System (INIS)

    Eko Sulistiyono; Murni Handayani

    2009-01-01

    Synthesis of poly(3,4-ethylenedioxy thiophene)-poly(styrene-4-sulfonate) composites for support fuel cell catalyst layer are synthesis composites which become fuel cell catalyst support so that catalyst has optimal performance. Main function of composites is support platinum particle for application in fuel cell. This article explains the result of composites production process from ( 3,4 Ethylenedioxy thiophene) and Sodium poly( styrene - 4-sulfonate) using two methods Jingning Shan method (method 1) and Zhigang Qi and Peter G.Pickup method (method 2). Analysis of the synthesis results used Scanning Electron Microscopic –Electron Dispersive X – Ray Spectrophotometer (SEM-EDS ). The analysis result show that both methods produce polymer agglomerate into a sponge-like morphology. Composite from method 1 has morphology, pores and proton transport better than composite produced by method 2. (author)

  3. An anodic alumina supported Ni-Pt bimetallic plate-type catalysts for multi-reforming of methane, kerosene and ethanol

    KAUST Repository

    Zhou, Lu

    2014-05-01

    An anodic alumina supported Ni-Pt bimetallic plate-type catalyst was prepared by a two-step impregnation method. The trace amount 0.08 wt% of Pt doping efficiently suppressed the nickel particle sintering and improved the nickel oxides reducibility. The prepared Ni-Pt catalyst showed excellent performance during steam reforming of methane, kerosene and ethanol under both 3000 h stationary and 500-time daily start-up and shut-down operation modes. Self-activation ability of this catalyst was evidenced, which was considered to be resulted from the hydrogen spillover effect over Ni-Pt alloy. In addition, an integrated combustion-reforming reactor was proposed in this study. However, the sintering of the alumina support is still a critical issue for the industrialization of Ni-Pt catalyst. Copyright © 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

  4. Titanium carbide and its core-shelled derivative TiC-TiO2 as catalyst supports for proton exchange membrane fuel cells

    International Nuclear Information System (INIS)

    Ignaszak, Anna; Song, Chaojie; Zhu, Weimin; Zhang, Jiujun; Bauer, Alex; Baker, Ryan; Neburchilov, Vladimir; Ye, Siyu; Campbell, Stephen

    2012-01-01

    Both TiC and core-shelled TiC-TiO 2 are investigated as catalyst supports for proton exchange membrane fuel cells (PEMFCs). TiC is thermally stable, possesses both low solubility in sulphuric acid and high electronic conductivity. However, TiC undergoes irreversible electrochemical oxidation in dilute perchloric acid and the operating potential range of 0–1.2 V RHE . TiC-TiO 2 core–shell composite is found to be more stable than TiC. Both these materials are used as supports for Pt and Pt–Pd alloy catalysts (Pt/TiC, Pt 3 Pd/TiC and Pt 3 Pd/TiC-TiO 2 ) and are synthesized by microwave-assisted polyol process. The catalytic activities of both Pt 3 Pd/TiC and Pt 3 Pd/TiC-TiO 2 toward the oxygen reduction reaction (ORR) are much higher than those for Pt/TiC. Accelerated durability tests show that TiC supported catalysts are not electrochemically stable. The corresponding TiC-TiO 2 supported catalyst is more stable than that supported by TiC, indicating that with a protective oxide layer on the TiC core, TiC-TiO 2 is a promising PEMFC catalyst support.

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

    International Nuclear Information System (INIS)

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

    2014-01-01

    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), H 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 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 5+ selectivity and a decrease in methane selectivity. Potassium was found to be a better promoter for Co/CNTs catalyst compared to platinum

  7. 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.

  8. 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.

  9. An introduction to catalyst

    International Nuclear Information System (INIS)

    Jeon, Hak Je

    1988-11-01

    This book explains basic conception of catalyst such as definition, velocity of chemical reaction and velocity of catalyst reaction, absorption with absorption energy and chemical absorption, pore structure with the role of pore and measurement of pore structure, catalyst activity on solid structure, electrical property on catalyst activity, choice and design of catalyst, catalytic reaction with reaction velocity and chemical equilibrium and reaction velocity model, measurement of reaction velocity and material analysis, catalyst for mixed compound, catalyst for solid acid and catalyst for supported metal.

  10. A review of carbon-based and non-carbon-based catalyst supports for the selective catalytic reduction of nitric oxide.

    Science.gov (United States)

    Anthonysamy, Shahreen Binti Izwan; Afandi, Syahidah Binti; Khavarian, Mehrnoush; Mohamed, Abdul Rahman Bin

    2018-01-01

    Various types of carbon-based and non-carbon-based catalyst supports for nitric oxide (NO) removal through selective catalytic reduction (SCR) with ammonia are examined in this review. A number of carbon-based materials, such as carbon nanotubes (CNTs), activated carbon (AC), and graphene (GR) and non-carbon-based materials, such as Zeolite Socony Mobil-5 (ZSM-5), TiO 2 , and Al 2 O 3 supported materials, were identified as the most up-to-date and recently used catalysts for the removal of NO gas. The main focus of this review is the study of catalyst preparation methods, as this is highly correlated to the behaviour of NO removal. The general mechanisms involved in the system, the Langmuir-Hinshelwood or Eley-Riedeal mechanism, are also discussed. Characterisation analysis affecting the surface and chemical structure of the catalyst is also detailed in this work. Finally, a few major conclusions are drawn and future directions for work on the advancement of the SCR-NH 3 catalyst are suggested.

  11. Wet chemical synthesis of nickel supported on alumina catalysts

    International Nuclear Information System (INIS)

    Freire, Ranny Rodrigues; Costa, Talita Kenya Oliveira; Morais, Ana Carla da Fonseca Ferreira; Costa, Ana Cristina Figueiredo de Melo; Freitas, Normanda Lino de

    2016-01-01

    Heterogenic catalysts are those found to be in a different phase on the reaction when compared to the reactants and products. Preferred when compared to homogeneous catalysts due to the easiness on which the separation is processed. The objective of this study is to obtain and characterize Alumina based catalysts impregnated with Nickel (Al_2O_3), by wet impregnation. The alumina was synthesized by combustion reaction. Before and after the impregnation the catalysts were characterized by X-ray diffraction (XRD), granulometric analysis, the textural analysis will be held by nitrogen adsorption (BET), energy-dispersive X-ray spectroscopy (EDX) and scanning electron microscopy (SEM). The results show a presence of a stable crystalline phase of Al2O3 in all the studied samples and after the impregnation the second phase formed was of NiO and NiAl_2O_4. The Al_2O_3 e Ni/Al_2O_3 catalysts resulted in clusters with a medium diameter of 18.9 and 14.2 μm, respectively. The catalysts show a medium-pore characteristic (medium pore diameter between 2 and 50 nm), the superficial area to Al_2O_3 and Ni/Al_2O_3 catalysts were 8.69 m"2/g and 5.56 m"2/g, respectively. (author)

  12. Oxidative-reforming of model biogas over NiO/Al{sub 2}O{sub 3} catalysts: The influence of the variation of support synthesis conditions

    Energy Technology Data Exchange (ETDEWEB)

    Asencios, Yvan J.O., E-mail: yvan.jesus@unifesp.br [Departamento de Ciências do Mar, Universidade Federal de São Paulo, Av. Alm. Saldanha da Gama, 89, Ponta da Praia, CEP: 11030-400, Santos-SP (Brazil); Elias, Kariny F.M. [Instituto de Química de São Carlos, Universidade de São Paulo, Av. Trabalhador Sãocarlense, 400, 13560-970, São Carlos-SP (Brazil); Assaf, Elisabete M., E-mail: eassaf@iqsc.usp.br [Instituto de Química de São Carlos, Universidade de São Paulo, Av. Trabalhador Sãocarlense, 400, 13560-970, São Carlos-SP (Brazil)

    2014-10-30

    Graphical abstract: - Highlights: • Precipitation pH and ageing T °C of Al{sub 2}O{sub 3} influenced the performance of Ni/Al{sub 2}O{sub 3}. • Ni catalysts supported on Al{sub 2}O{sub 3} obtained at pH 7 recorded high conversion values. • Catalysts supported on Al{sub 2}O{sub 3} obtained at pH 7 and 80 °C are promissory for reforming of biogas. • Catalysts supported on Al{sub 2}O{sub 3} obtained at pH 6 deactivated readily during reaction. - Abstract: In this study, nickel catalysts (20 wt%) supported on γ-Al{sub 2}O{sub 3} were prepared by the impregnation method. The γ-Al{sub 2}O{sub 3}, was synthesized by precipitation of bayerite gel obtained from aluminum scrap. The synthetic conditions of the bayerite gel varied as follows: precipitation pH ranging from 6 to 7; ageing temperature ranging from 25 to 80 °C, the calcination temperature for all samples was 500 °C. The catalysts and the supports were analyzed by temperature programmed reduction (H{sub 2}-TPR), X-ray diffraction (XRD), physisorption of N{sub 2} (BET), X-ray absorption near-edge structure (XANES) and scanning electron microscopy (SEM). Isopropanol decomposition reactions over the catalysts were carried out to evaluate their acidity. SEM images of the spent catalysts showed that the morphology of the carbon formed during the reaction is of the filamentous type. The TPR analysis of the catalysts showed the presence of NiO species weakly interacted with the support as well as stoichiometric and non-stoichiometric nickel aluminate, the reduction of these species was also observed by XANES analysis. XRD analysis of the fresh catalyst showed peaks assigned to NiO, NiAl{sub 2}O{sub 4} and γ-Al{sub 2}O{sub 3}. The best catalysts (samples NiAl7-25 and NiAl7-80) synthesized in this report showed high stability and high conversion values (CH{sub 4} (70%) and CO{sub 2} (78%)). These catalysts showed better performance than the catalyst supported on commercial γ-Al{sub 2}O{sub 3}, which showed a

  13. Synthesis of dimethyl carbonate (DMC) by oxidative carbonylation of methanol using polymer-supported CuCl{sub 2} catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Y. [Daicel Chemical Industries, Ltd., Hyogo (Japan). Research Center; Kobe University, Kobe (Japan); Kagotani, M. [Daicel Chemical Industries, Ltd., Hyogo (Japan). Research Center; Soma, Y. [Osaka National Research Institute, Osaka (Japan)

    2000-01-01

    Polymer, including 2,2'-bipyridine, poly(4-methyl-4'-vinyl-2,2'-bipyridine)(Pvbpy), was investigated for the synthesis of dimethyl carbonate (DMC) as a support for CuCl{sub 2}, by oxidative carbonylation of methanol in the liquid-phase. The CuCl{sub 2} complex (Pvbpy-CuCl{sub 2}) was insoluble in methanol, and the reaction system was heterogeneous. The Pvbpy-CuCl{sub 2} catalyst showed considerable catalytic activity (DMC yield: 44.4 % and DMC selectivity: 9206 %, at methanol conversion: 1.79 %), which is comparable to the previously reported data of poly (vinylpyridine) (PVP)-CuCl{sub 2} catalyst; the Pvbpy-CuCl{sub 2} catalyst could be recycled after filtration and washing thrice, provided, not having lost activity. The corrosion originating from Cl{sup -} was greatly improved by immobilizing the CuCl{sub 2} by Pvbpy. Elimination of CuCl{sub 2} from the Pvbpy support was observed during the reaction. In the first reaction, about 38 % of the initially supported Cl was released, and in the second and the third reactions, most of the Cl was retained. The rate of corrosion of stainless steels in the first use of the catalyst (0.6 mg h{sup -1} for HC276) was greater than that in the rate of the second and the third uses (<0.1 mg h{sup -1}). These results are closely related to the amount of Cl{sup -} released from the Pvbpy support, which demonstrates that the main cause of corrosion in the catalytic system is Cl{sup -} released from the Pvbpy-CuCl{sub 2} catalyst. From XPS study of the catalyst, it became obvious that Cu(2) was gradually reduced to Cu(1) during the reaction. (author)

  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. Single-Atom Catalyst of Platinum Supported on Titanium Nitride for Selective Electrochemical Reactions.

    Science.gov (United States)

    Yang, Sungeun; Kim, Jiwhan; Tak, Young Joo; Soon, Aloysius; Lee, Hyunjoo

    2016-02-05

    As a catalyst, single-atom platinum may provide an ideal structure for platinum minimization. Herein, a single-atom catalyst of platinum supported on titanium nitride nanoparticles were successfully prepared with the aid of chlorine ligands. Unlike platinum nanoparticles, the single-atom active sites predominantly produced hydrogen peroxide in the electrochemical oxygen reduction with the highest mass activity reported so far. The electrocatalytic oxidation of small organic molecules, such as formic acid and methanol, also exhibited unique selectivity on the single-atom platinum catalyst. A lack of platinum ensemble sites changed the reaction pathway for the oxygen-reduction reaction toward a two-electron pathway and formic acid oxidation toward direct dehydrogenation, and also induced no activity for the methanol oxidation. This work demonstrates that single-atom platinum can be an efficient electrocatalyst with high mass activity and unique selectivity. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Preparation and characterization of multi-walled carbon nanotube (MWCNTs)-supported Pt-Ru catalyst for methanol electrooxidation

    Energy Technology Data Exchange (ETDEWEB)

    Yang Chunwei [Department of Applied Chemistry, Harbin Institute of Technology, Harbin 150001 (China)], E-mail: cw.yang@hit.edu.cn; Wang Dianlong; Hu Xinguo; Dai Changsong [Department of Applied Chemistry, Harbin Institute of Technology, Harbin 150001 (China); Zhang Liang [School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081 (China)

    2008-01-10

    Multi-walled carbon nanotubes (MWCNTs) as a support of PtRu catalyst nanocomposites were prepared by colloid method in this work. Transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) all indicate that ultrasonic treatment can effectively functionalize MWCNTs, endowing them with groups that can act as nucleation sites which can favor well-dispersed deposition of PtRu clusters on their surface. The PtRu/MWCNTs catalysts have a high and homogeneous dispersion of spherical PtRu metal particles with a narrow particle-size distribution. From XPS tests, in PtRu/MWCNTs catalysts Ru can weaken the out-shell electrons of Pt because a part of Ru form alloy with Pt. The remnant Ru exists in oxidation and provides abundant oxygen to nearby Pt, as accelerated desorption and oxidation of intermediate products of methanol oxidation at surface of Pt. By a series of electrochemistry measurements, the PtRu/MWCNTs catalysts display significantly higher performance than the PtRu/XC-72 catalysts. Finally, schematic procedures for the oxidation of MWCNTs and synthesis of PtRu/MWCNTs catalysts were given.

  17. Preparation and characterization of multi-walled carbon nanotube (MWCNTs)-supported Pt-Ru catalyst for methanol electrooxidation

    International Nuclear Information System (INIS)

    Yang Chunwei; Wang Dianlong; Hu Xinguo; Dai Changsong; Zhang Liang

    2008-01-01

    Multi-walled carbon nanotubes (MWCNTs) as a support of PtRu catalyst nanocomposites were prepared by colloid method in this work. Transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) all indicate that ultrasonic treatment can effectively functionalize MWCNTs, endowing them with groups that can act as nucleation sites which can favor well-dispersed deposition of PtRu clusters on their surface. The PtRu/MWCNTs catalysts have a high and homogeneous dispersion of spherical PtRu metal particles with a narrow particle-size distribution. From XPS tests, in PtRu/MWCNTs catalysts Ru can weaken the out-shell electrons of Pt because a part of Ru form alloy with Pt. The remnant Ru exists in oxidation and provides abundant oxygen to nearby Pt, as accelerated desorption and oxidation of intermediate products of methanol oxidation at surface of Pt. By a series of electrochemistry measurements, the PtRu/MWCNTs catalysts display significantly higher performance than the PtRu/XC-72 catalysts. Finally, schematic procedures for the oxidation of MWCNTs and synthesis of PtRu/MWCNTs catalysts were given

  18. Efficient method for the conversion of agricultural waste into sugar alcohols over supported bimetallic catalysts.

    Science.gov (United States)

    Tathod, Anup P; Dhepe, Paresh L

    2015-02-01

    Promoter effect of Sn in the PtSn/γ-Al2O3 (AL) and PtSn/C bimetallic catalysts is studied for the conversion of variety of substrates such as, C5 sugars (xylose, arabinose), C6 sugars (glucose, fructose, galactose), hemicelluloses (xylan, arabinogalactan), inulin and agricultural wastes (bagasse, rice husk, wheat straw) into sugar alcohols (sorbitol, mannitol, xylitol, arabitol, galactitol). In all the reactions, PtSn/AL showed enhanced yields of sugar alcohols by 1.5-3 times than Pt/AL. Compared to C, AL supported bimetallic catalysts showed prominent enhancement in the yields of sugar alcohols. Bimetallic catalysts characterized by X-ray diffraction study revealed the stability of catalyst and absence of alloy formation thereby indicating that Pt and Sn are present as individual particles in PtSn/AL. The TEM analysis also confirmed stability of the catalysts and XPS study disclosed formation of electron deficient Sn species which helps in polarizing carbonyl bond to achieve enhanced hydrogenation activity. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Improved hydrogen generation from alkaline NaBH{sub 4} solution using cobalt catalysts supported on modified activated carbon

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Dongyan; Guo, Qingjie; Yue, Xuehai [College of Chemical Engineering, Qingdao University of Science and Technology, Qingdao 266042 (China); Dai, Ping [College of Electromechanical Engineering, Qingdao University of Science and Technology, Qingdao 266061 (China)

    2008-12-15

    Hydrogen production from alkaline sodium borohydride (NaBH{sub 4}) solution via hydrolysis process over activated carbon supported cobalt catalysts is studied. Activated carbons are used in their original form and after liquid phase oxidation with HNO{sub 3}. The changes in surface functional groups of the activated carbon are detected by FTIR spectroscopy. The effects of HNO{sub 3} oxidation on the properties of the activated carbon and the resulting catalyst performance are investigated. FTIR analysis reveals that the oxidative treatment leads to the formation of various functional groups on the surface of the activated carbon. Cobalt catalysts supported on the modified activated carbon are found to exhibit higher activity and stability. (author)

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

    Directory of Open Access Journals (Sweden)

    Cinthia Alegre

    2015-03-01

    Full Text Available 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-ray diffraction and transmission electron microscopy were applied. Cyclic voltammetry and chronoamperometry were used for studying carbon monoxide and methanol oxidation. Catalysts supported on carbon xerogel presented higher catalytic activities towards CO and CH3OH oxidation than catalysts supported on Vulcan. The higher mesoporosity of carbon xerogel was responsible for the favored diffusion of reagents towards catalytic centers.

  1. Supported Co-Mn-Al Mixed Oxides as Catalysts for N2O Decomposition.

    Czech Academy of Sciences Publication Activity Database

    Pacultová, K.; Karásková, C.; Strakošová, J.; Jirátová, Květa; Obalová, L.

    2015-01-01

    Roč. 18, č. 20 (2015), s. 1114-1122 ISSN 1631-0748. [AWPAC2014 - International Symposium on Air & Water Pollution Abatement Catalysis. Krakow, 01.09.2014-05.09.2014] R&D Projects: GA ČR GA14-13750S Institutional support: RVO:67985858 Keywords : supported catalysts * heterogeneous catalysis * spinel phase * nitrogen oxides Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 1.798, year: 2015

  2. Synthesis of honeycomb-like mesoporous nitrogen-doped carbon nanospheres as Pt catalyst supports for methanol oxidation in alkaline media

    Science.gov (United States)

    Zhang, Yunmao; Liu, Yong; Liu, Weihua; Li, Xiying; Mao, Liqun

    2017-06-01

    This paper reports the convenient synthesis of honeycomb-like mesoporous nitrogen-doped carbon spheres (MNCS) using a self-assembly strategy that employs dopamine (DA) as a carbon and nitrogen precursor and a polystyrene-b-poly(ethylene oxide) (PS173-b-PEO170) diblock copolymer as a soft template. The MNCS have large BET surface areas of up to 554 m2 g-1 and high nitrogen contents of up to 6.9 wt%. The obtained MNCS are used as a support for Pt catalysts, which promote methanol oxidation in alkaline media. The MNCS-supported Pt (Pt/MNCS) catalyst has a larger electrochemically active surface area (ESA) (89.2 m2 g-1) than does a commercially available Vulcan XC-72R supported Pt/C catalyst. Compared to the Pt/C catalyst, Pt/MNCS displays a higher peak current density (1007 mA mg-1) and is more stable during methanol oxidation. These improvements are attributed to the honeycomb-like porous structure of the MNCS and the introduction of nitrogen to the carbon support. The MNCS effectively stabilize Pt nanoparticles and assuage the agglomeration of the nanoparticles, suggesting that MNCS are potential and promising application as electrocatalyst supports in alkaline direct methanol fuel cells.

  3. Support effects in single atom iron catalysts on adsorption characteristics of toxic gases (NO2, NH3, SO3 and H2S)

    Science.gov (United States)

    Gao, Zhengyang; Yang, Weijie; Ding, Xunlei; Lv, Gang; Yan, Weiping

    2018-04-01

    The effects of support on gas adsorption is crucial for single atom catalysts design and optimization. To gain insight into support effects on gas adsorption characteristics, a comprehensive theoretical study was performed to investigate the adsorption characteristics of toxic gases (NO2, NH3, SO3 and H2S) by utilizing single atom iron catalysts with three graphene-based supports. The adsorption geometry, adsorption energy, electronic and magnetic properties of the adsorption system have been explored. Additionally, the support effects have been analyzed through d-band center and Fermi softness, and thermodynamic analysis has been performed to consider the effect of temperature on gas adsorption. The support effects have a remarkable influence on the adsorption characteristics of four types of toxic gases which is determined by the electronic structure of graphene-based support, and the electronic structure can be characterized by Fermi softness of catalysts. Fermi softness and uplift height of Fe atom could be good descriptors for the adsorption activity of single atom iron catalysts with graphene-based supports. The findings can lay a foundation for the further study of graphene-based support effects in single atom catalysts and provide a guideline for development and design of new graphene-based support materials utilizing the idea of Fermi softness.

  4. Remarkable support effect on the reactivity of Pt/In2O3/MOx catalysts for methanol steam reforming

    Science.gov (United States)

    Liu, Xin; Men, Yong; Wang, Jinguo; He, Rong; Wang, Yuanqiang

    2017-10-01

    Effects of supports over Pt/In2O3/MOx catalysts with extremely low loading of Pt (1 wt%) and In2O3 loadings (3 wt%) are investigated for the hydrogen production of methanol steam reforming (MSR) in the temperature range of 250-400 °C. Under practical conditions without the pre-reduction, the 1Pt/3In2O3/CeO2 catalyst shows the highly efficient catalytic performance, achieving almost complete methanol conversion (98.7%) and very low CO selectivity of 2.6% at 325 °C. The supported Pt/In2O3 catalysts are characterized by means of Brunauer-Emmett-Teller (BET) surface area, X-ray diffraction (XRD), high-resolution transmission microscopy (HRTEM), temperature programmed reduction with hydrogen (H2-TPR), CO pulse chemisorption, temperature programmed desorption of methanol and water (CH3OH-TPD and H2O-TPD). These demonstrate that the nature of catalyst support of Pt/In2O3/MOx plays crucial roles in the Pt dispersion associated by the strong interaction among Pt, In2O3 and supporting materials and the surface redox properties at low temperature, and thus affects their capability to activate the reactants and determines the catalytic activity of methanol steam reforming. The superior 1Pt/3In2O3/CeO2 catalyst, exhibiting a remarkable reactivity and stability for 32 h on stream, demonstrates its potential for efficient hydrogen production of methanol steam reforming in mobile and de-centralized H2-fueled PEMFC systems.

  5. Characterization of alumina supported molybdenum catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Pastura, N M; Carmo, L M.P.M.; Sachett, C M.M.; Lam, Y L [Instituto Militar de Engenharia, Rio de Janeiro (Brazil). Secao de Quimica

    1983-10-01

    In order to optimize a bifunctional catalyst (acid and hydrogenating) of Mo/Al/sub 2/O/sub 3/, oxygen adsorption at 195 K and ethanol dehydration at 480-520 K were carried out using a series of these catalysts. The increase of Mo content increased the quantity of adsorbed oxygen, thus indicating that the number of hydrogenating sites also increased. The specific activity of ethanol dehydration varied slightly, indicating that the number of acid sites remains almost constant. On the other hand, the selectivity in ethylene (versus ether) increased markedly. This may be attributed to the increase in acid force of the acid sites.

  6. Characterization of alumina supported molybdenum catalysts

    International Nuclear Information System (INIS)

    Pastura, N.M.; Carmo, L.M.P.M.; Sachett, C.M.M.; Lam, Y.L.

    1983-01-01

    In order to optimize a bifunctional catalyst (acid and hydrogenating) of Mo/Al 2 O 3 , oxygen adsorption at 195 K and ethanol dehydration at 480-520 K were carried out using a series of these catalysts. The increase of Mo content increased the quantity of adsorbed oxygen, thus indicating that the number of hydrogenating sites also increased. The specific activity of ethanol dehydration varied slightly, indicating that the number of acid sites remains almost constant. On the other hand, the selectivity in ethylene (versus ether) increased markedly. This may be attributed to the increase in acid force of the acid sites. (C.L.B.) [pt

  7. Influence of pore structure and chemical properties of supported Mo catalysts on their performance in upgrading heavy coal liquids

    Energy Technology Data Exchange (ETDEWEB)

    Song, C.; Hanaoka, K.; Nomura, M. (Pennsylvania State University, University Park, PA (USA). Dept. of Materials Science and Engineering)

    In the hydroprocessing of solvent-refined coals, both the pore structure and the chemical properties of the catalysts affect the conversion of the heavy materials. Increasing median pore diameter (MPD) of unimodal Ni-Mo/Al[sub 2]O[sub 3] catalysts in the relatively small pore region (up to 150 [angstrom]) enhanced the conversion of both asphaltene and preasphaltene, but further increasing the MPD up to 730 [angstrom] mainly promoted preasphaltene conversion. In the runs of the isolated fractions, however, conversions increased with MPD up to 290 [angstrom] for asphaltene and up to 730 [angstrom] for preasphaltene. The degree of heteroatom removal is also influenced by MPD. There exist preferable pore size ranges for hydrodeoxygenation. Two Mo/SiO[sub 2] and several carbon-coated Ni-Mo/Al[sub 2]O[sub 3] catalysts with different MPD and a commercial Ni-Mo supported on silicated Al[sub 2]O[sub 3] were also compared. The increasing MPD of SiO[sub 2]-supported Mo catalysts increased the conversion of preasphaltene materials. Mo/SiO[sub 2] catalysts are more effective than Ni-Mo supported on Al[sub 2]O[sub 3] and silicated Al[sub 2]O[sub 3] for converting preasphaltene materials, while the latter two are more active for conversion of asphaltene into oil. Another interesting observation is that, for a given MPD range, the carbon-coated Ni-Mo/Al[sub 2]O[sub 3] catalysts gave higher preasphaltene conversions than fresh ones. These results point to the conclusion that larger pore and less acidic hydrogenation catalysts are more effective for preasphaltene conversion, but efficient conversion of asphaltene into oil is facilitated by mild hydrocracking catalysts having appropriate pore size ranges. 43 refs., 8 figs., 9 tabs.

  8. 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

  9. Preparation Effects on the Performance of Silica-Doped Hydrous Titanium Oxide (HTO:Si)-Supported Pt Catalysts for Lean-Burn NOx Reduction by Hydrocarbons; TOPICAL

    International Nuclear Information System (INIS)

    GARDNER, TIMOTHY J.; MCLAUGHLIN, LINDA I.; MOWERY, DEBORAH L.; SANDOVAL, RONALD S.

    2002-01-01

    This report describes the development of bulk hydrous titanium oxide (HTO)- and silica-doped hydrous titanium oxide (HTO:Si)-supported Pt catalysts for lean-burn NOx catalyst applications. The effects of various preparation methods, including both anion and cation exchange, and specifically the effect of Na content on the performance of Pt/HTO:Si catalysts, were evaluated. Pt/HTO:Si catalysts with low Na content ( and lt; 0.5 wt.%) were found to be very active for NOx reduction in simulated lean-burn exhaust environments utilizing propylene as the major reductant species. The activity and performance of these low Na Pt/HTO:Si catalysts were comparable to supported Pt catalysts prepared using conventional oxide or zeolite supports. In ramp down temperature profile test conditions, Pt/HTO:Si catalysts with Na contents in the range of 3-5 wt.% showed a wide temperature window of appreciable NOx conversion relative to low Na Pt/HTO:Si catalysts. Full reactant species analysis using both ramp up and isothermal test conditions with the high Na Pt/HTO:Si catalysts, as well as diffuse reflectance FTIR studies, showed that this phenomenon was related to transient NOx storage effects associated with NaNO(sub 2)/NaNO(sub 3) formation. These nitrite/nitrate species were found to decompose and release NOx at temperatures above 300 C in the reaction environment (ramp up profile). A separate NOx uptake experiment at 275 C in NO/N(sub 2)/O(sub 2) showed that the Na phase was inefficiently utilized for NOx storage. Steady state tests showed that the effect of increased Na content was to delay NOx light-off and to decrease the maximum NOx conversion. Similar results were observed for high K Pt/HTO:Si catalysts, and the effects of high alkali content were found to be independent of the sample preparation technique. Catalyst characterization (BET surface area, H(sub 2) chemisorption, and transmission electron microscopy) was performed to elucidate differences between the HTO- and HTO:Si-supported

  10. Silica-Supported Catalyst for Enantioselective Arylation of Aldehydes under Batch and Continuous-Flow Conditions.

    Science.gov (United States)

    Watanabe, Satoshi; Nakaya, Naoyuki; Akai, Junichiro; Kanaori, Kenji; Harada, Toshiro

    2018-05-04

    A silica-supported 3-aryl H 8 -BINOL-derived titanium catalyst exhibited high performance in the enantioselective arylation of aromatic aldehydes using Grignard and organolithium reagents not only under batch conditions but also under continuous-flow conditions. Even with a simple pipet reactor packed with the heterogeneous catalyst, the enantioselective production of chiral diarylmethanols could be achieved through a continuous introduction of aldehydes and mixed titanium reagents generated from the organometallic precursors. The pipet reactor could be used repeatedly in different reactions without appreciable deterioration of the activity.

  11. Non-carbon titanium cobalt nitride nanotubes supported platinum catalyst with high activity and durability for methanol oxidation reaction

    Science.gov (United States)

    Chen, Xiaoxiang; Li, Wuyi; Pan, Zhanchang; Xu, Yanbin; Liu, Gen; Hu, Guanghui; Wu, Shoukun; Li, Jinghong; Chen, Chun; Lin, Yingsheng

    2018-05-01

    Titanium cobalt nitride nanotubes (Ti0.95Co0.05N NTs) hybrid support, a novel robust non-carbon support material prepared by solvothermal and post-nitriding processes, is further decorated with Pt nanoparticles for the electrooxidation of methanol. The catalyst is characterized by X-ray diffraction (XRD), nitrogen adsorption/desorption, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and electrochemical measurements. The morphology, structure and composition of the synthesized Ti0.95Co0.05N NTs suggest that the nanotube wall is porous and consists of homogeneous cohesively attached nitrides nanocube particles. Notable, Ti0.95Co0.05N NTs supported Pt catalyst exhibits significantly improved catalytic activity and durability for methanol electrooxidation compared with the conventional JM Pt/C catalyst. The experimental data indicate that enhanced catalytic activity and stability of Pt/Ti0.95Co0.05N NTs towards methanol electrooxidation might be mainly attributed to the tubular nanostructures and synergistic effect introduced by the Co doping. Both of them are playing an important role in improving the activity and durability of the Ti0.95Co0.05N NTs catalyst.

  12. Supported Catalysts for CO2 Methanation: A Review

    Directory of Open Access Journals (Sweden)

    Patrizia Frontera

    2017-02-01

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

  13. Preparation and characterization of nickel catalysts supported on cerium for obtaining hydrogen from steam reforming of ethanol

    International Nuclear Information System (INIS)

    Urbaninho, A.B.; Bergamaschi, V.S.; Ferreira, J.C.

    2016-01-01

    The Ni/Ce catalysts for were prepared by co- precipitation method with a view to their use in steam reforming of ethanol to produce a hydrogen-rich gas mixture. The catalysts were characterized by scanning electron microscopy; x-ray dispersive Spectroscopy and surface area BET method. This paper proposes to prepare, characterize and test nickel catalyst supported on cerium in order to obtain a material with higher activity and selectivity of the catalyst using the steam reforming reaction of ethanol, by varying the reaction temperature, molar ratio water/ethanol and uptime. The catalytic tests were monitored by chemical analysis of syngas from steam reforming of ethanol using an analysis online by gas Chromatograph in the reactor. (author)

  14. Single Pot Selective Hydrogenation of Furfural to 2-Methylfuran Over Carbon Supported Iridium Catalysts

    KAUST Repository

    Date, Nandan S; Hengne, Amol Mahalingappa; Huang, Kuo-Wei; Chikate, Rajeev C.; Rode, C. V.

    2018-01-01

    Various iridium supported carbon catalysts were prepared and screened for direct hydrogenation of furfural (FFR) to 2-methyl furan (2-MF). Amongest these, 5% Ir/C showed excellent results with complete FFR conversion and highest selectivity of 95% to 2-MF at very low H2 pressure of 100 psig. Metallic (Iro) and oxide ( IrO2) phases of Ir catalyzed first step hydrogenation involving FFR to FAL and subsequent hydrogenation to 2-MF,respecively. This was confirmed by XPS analysis and some controlled experiments. At low temperature of 140 oC, almost equal selectivities of FAL (42%) and 2-MF (43%) were observed, while higher temperature (220oC) favored selective hydrodeoxygenation. At optimized temperature, 2-MF formed selectively while higher pressure and higher catalyst loading favored ring hydrogenation of furfural rather than side chain hydrogenation. With combination of several control experimental results and detailed catalyst characterization, a plausible reaction pathway has been proposed for selective formation of 2-MF. The selectivity to various other products in FFR hydrogenation can be manipulated by tailoring the reaction conditions over the same catalyst.

  15. Single Pot Selective Hydrogenation of Furfural to 2-Methylfuran Over Carbon Supported Iridium Catalysts

    KAUST Repository

    Date, Nandan S

    2018-03-20

    Various iridium supported carbon catalysts were prepared and screened for direct hydrogenation of furfural (FFR) to 2-methyl furan (2-MF). Amongest these, 5% Ir/C showed excellent results with complete FFR conversion and highest selectivity of 95% to 2-MF at very low H2 pressure of 100 psig. Metallic (Iro) and oxide ( IrO2) phases of Ir catalyzed first step hydrogenation involving FFR to FAL and subsequent hydrogenation to 2-MF,respecively. This was confirmed by XPS analysis and some controlled experiments. At low temperature of 140 oC, almost equal selectivities of FAL (42%) and 2-MF (43%) were observed, while higher temperature (220oC) favored selective hydrodeoxygenation. At optimized temperature, 2-MF formed selectively while higher pressure and higher catalyst loading favored ring hydrogenation of furfural rather than side chain hydrogenation. With combination of several control experimental results and detailed catalyst characterization, a plausible reaction pathway has been proposed for selective formation of 2-MF. The selectivity to various other products in FFR hydrogenation can be manipulated by tailoring the reaction conditions over the same catalyst.

  16. Catalytic hydrotreatment of fast pyrolysis oil using bimetallic Ni-Cu catalysts on various supports

    NARCIS (Netherlands)

    Ardiyanti, A. R.; Khromova, S. A.; Venderbosch, R. H.; Yakovlev, V. A.; Melian-Cabrera, I. V.; Heeres, H. J.

    2012-01-01

    Bimetallic Ni-Cu catalysts on various Supports (CeO2-ZrO2, ZrO2, SiO2, TiO2, rice husk carbon, and Sibunite) with metal contents ranging from 7.5 to 9.0 (Ni) and 3.1-3.6 wt.% (Cu) for the inorganic supports and 17.1-17.8 (Ni) and 7.1-7.8 (Cu) for the carbon supports were synthesised and screened for

  17. Effects of supported (nBuCp)2ZrCl2 catalyst active center multiplicity on crystallization kinetics of ethylene homo- and copolymers

    KAUST Repository

    Atiqullah, Muhammad; Adamu, Sagir; Hossain, Mohammad Mozahar; Al-Harthi, Mamdouh A.; Anantawaraskul, Siripon; Hossaen, Anwar

    2014-01-01

    Two different supported zirconocene, that is, bis(n-butylcyclopentadienyl) zirconium dichloride (nBuCp)2ZrCl2, catalysts were synthesized. Each catalyst was used to prepare one ethylene homopolymer and one ethylene-1-hexene copolymer. Catalyst

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

    NARCIS (Netherlands)

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

    2013-01-01

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

  19. Calcium oxide supported gold nanoparticles as catalysts for the selective epoxidation of styrene by t-butyl hydroperoxide.

    Science.gov (United States)

    Dumbre, Deepa K; Choudhary, Vasant R; Patil, Nilesh S; Uphade, Balu S; Bhargava, Suresh K

    2014-02-01

    Gold nanoparticles are deposited on basic CaO supports as catalysts for the selective conversion of styrene into styrene oxide. Synthetic methods, gold loading and calcination temperatures are varied to permit an understanding of their influence on gold nanoparticle size, the presence of cationic gold species and the nature of interaction between the gold nanoparticles and the CaO support. Based on these studies, optimal conditions are designed to make the Au/CaO catalyst efficient for the selective epoxidation of styrene. Copyright © 2013 Elsevier Inc. All rights reserved.

  20. Study on supported binary sulfide catalysts for secondary hydrogenation of coal-derived liquids; Sekitan ekikayu niji suisoka shokubai no kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Shimada, H.; Matsubayashi, N.; Sato, T.; Imamura, M.; Yoshimura, Y.; Nishijima, A. [National Institute of Materials and Chemical Research, Tsukuba (Japan)

    1995-07-28

    To utilize the high performance of supported catalysts in coal liquefaction processes, one of the promising ways is to apply hydroprocessing sulfide catalysts to the secondary hydrogenation of coal-derived liquids which have undergone the solid separation unit. However, when the product yield from the first-stage liquefaction is maximized, the feed stocks in the secondary hydrogenation contain large amounts of residual fractions with preasphaltenes and metallic components. In this case, the development of a long-life catalyst is essential to establish the two-stage process as a practical one. From this viewpoint, the authors have investigated the deactivation causes of supported Ni-Mo sulfide catalysts through the analysis of the used catalysts in the secondary hydrogenation of coal-derived liquids for long periods. The major cause of the catalyst deactivation has been found to be metallic and carbonaceous deposition on the catalyst, which results thin layer which covers the catalyst particles. The catalysts located at the reactor inlet are more rapidly deactivated than those at the rector exit because of larger amounts of metallic foul ants and the above described shell-like layer. Hydrocracking active sites are much heavily deactivated compared with hydrogenation active sites. It is inferred that the basic or polar compounds contained in coal liquids are permanency adsorbed on the hydrocracking active sites. Spectroscopic analysis of the used catalysts clarified the destruction of the active phase of the binary sulfides, through the segregation and crystal growth. The structural changes of the catalysts are very likely caused by heteroatom compounds in the preasphaltenes. Thus, the primary cause of the catalyst deactivation is the preasphaltenes in the coal liquids. Hydroaromatic compounds in the coal liquids suppress the change of the deposited carbonaceous materials into inert coke which permanently deactivate the catalyst.

  1. Silica-Supported Co3O4 Nanoparticles as a Recyclable Catalyst for Rapid Degradation of Azodye

    Directory of Open Access Journals (Sweden)

    Ali Baghban

    2016-10-01

    Full Text Available In this paper, silica nanoparticles with particle size of ~ 10-20 nm were selected as a support for the synthesis of Co3O4 nanoparticles by impregnation of silica nanoparticles in solution of Co(II in a specific concentrations and then calcination to 800 oC. This nanocomposite was then, used as a catalyst for oxidative degradation of methyl orange (MO with ammonium persulfate in aqueous media. Effect of pH, temperature, contact time, amount of oxidant and catalyst were studied in the presence of manuscript. Scanning electron microscope (SEM, electron dispersive spectroscopy (EDS, FT-IR, and ICP-AES analyses were used for analysis of silica-supported Co3O4 (Co3O4/SiO2. Treating MO with ammonium persulfate in the presence of Co3O4/SiO2 led to complete degradation of MO under the optimized conditions. Also, the catalyst exhibited recyclability at least over 10 consecutive runs. Copyright © 2016 BCREC GROUP. All rights reserved Received: 12nd December 2015; Revised: 27th January 2016; Accepted: 27th January 2016 How to Cite: Baghban, A., Doustkhah, E., Rostamnia, S., Aghbash, K.O. (2016. Silica-Supported Co3O4 Nanoparticles as a Recyclable Catalyst for Rapid Degradation of Azodye. Bulletin of Chemical Reaction Engineering & Catalysis, 11 (3: 284-291 (doi:10.9767/bcrec.11.3.568.284-291 Permalink/DOI: http://doi.org/10.9767/bcrec.11.3.568.284-291

  2. Performance of supported catalysts for water electrolysis

    OpenAIRE

    Gurrik, Stian

    2012-01-01

    The most active catalyst for oxygen evolution in PEM water electrolysis is ruthenium oxide. Its major drawback as a commercial catalyst is its poor stability. In a mixed oxide with iridium, ruthenium becomes more stable. However, it would be favorable to find a less expensive substitute to iridium. In this work, the dissolution potential and lifetime of mixed oxides containing ruthenium and tantalum are investigated. In order to effectively determine what effects tantalum and particle size ha...

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

    International Nuclear Information System (INIS)

    Ahmad, N.; Ali, Z.; Abbas, S. M.; Hussain, F.

    2015-01-01

    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)

  4. Methods of making textured catalysts

    Science.gov (United States)

    Werpy, Todd [West Richland, WA; Frye, Jr., John G.; Wang, Yong [Richland, WA; Zacher, Alan H [Kennewick, WA

    2010-08-17

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

  5. 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...

  6. Natural phosphate-supported palladium: A highly efficient and recyclable catalyst for the suzuki-miyaura coupling under microwave irradiation

    KAUST Repository

    Hassine, Ayoub; Bouhrara, Mohamed; Sebti, Said; Solhy, Abderrahim; Mahfouz, Remi; Luart, Denis; Lene, Christophe; Fihri, Aziz

    2015-01-01

    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.

  7. 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.

  8. Robust non-carbon titanium nitride nanotubes supported Pt catalyst with enhanced catalytic activity and durability for methanol oxidation reaction

    International Nuclear Information System (INIS)

    Xiao, Yonghao; Zhan, Guohe; Fu, Zhenggao; Pan, Zhanchang; Xiao, Chumin; Wu, Shoukun; Chen, Chun; Hu, Guanghui; Wei, Zhigang

    2014-01-01

    By the combination of solvothermal alcoholysis and post-nitriding method, titanium nitride nanotubes (TiN NTs), with high surface area, hollow and interior porous structure are prepared successfully and used at a support for Pt nanoparticles. The TiN NTs supported Pt (Pt/TiN NTs) catalyst displays enhanced activity and durability towards methanol oxidation reaction (MOR) compared with the commercial Pt/C (E-TEK) catalyst. X ray diffraction (XRD), nitrogen adsorption/desorption, transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) measurements are performed to investigate the physicochemical properties of the synthesized catalyst. SEM and TEM images reveal that the wall of the TiN NTs is porous and Pt nanoparticles supported on the dendritic TiN nanocrystals exhibit small size and good dispersion. Effects of inherent corrosion-resistant, tubular and porous nanostructures and electron transfer due to the strong metal–support interactions of TiN NTs contribute to the enhanced catalytic activity and stability of Pt/TiN NTs towards the MOR

  9. Metal Oxide Supported Vanadium Substituted Keggin Type Polyoxometalates as Catalyst For Oxidation of Dibenzothiophene

    Science.gov (United States)

    Lesbani, Aldes; Novri Meilyana, Sarah; Karim, Nofi; Hidayati, Nurlisa; Said, Muhammad; Mohadi, Risfidian; Miksusanti

    2018-01-01

    Supported polyoxometalatate H4[γ-H2SiV2W10O40]·nH2O with metal oxide i.e. silica, titanium, and tantalum was successfully synthesized via wet impregnation method to form H4[γ-H2SiV2W10O40]·nH2O-Si, H4[γ-H2SiV2W10O40]·nH2O-Ti, and H4[γ-H2SiV2W10O40]·nH2O-Ta. Characterization was performed using FTIR spectroscopy, X-Ray analyses, and morphology analyses using SEM. All compounds were used as the catalyst for desulfurization of dibenzothiophene (DBT). Silica and titanium supported polyoxometalate H4[γ-H2SiV2W10O40]·nH2O better than tantalum due to retaining crystallinity after impregnation process. On the other hand, compound H H4[γ-H2SiV2W10O40]·nH2O-Ta showed high catalytic activity than other supported metal oxides for desulfurization of DBT. Optimization desulfurization process resulted in 99% conversion of DBT under a mild condition at 70 °C, 0.1 g catalyst, and reaction for 3 hours. Regeneration studies showed catalyst H4[γ-H2SiV2W10O40]·nH2O-Ti was remaining catalytic activity for desulfurization of DBT.

  10. A combined in situ XAS-XRPD-Raman study of Fischer-Tropsch synthesis over a carbon supported Co catalyst

    DEFF Research Database (Denmark)

    Tsakoumis, Nikolaos E.; Dehghan, Roya; Johnsen, Rune

    2013-01-01

    A cobalt based Fischer-Tropsch synthesis (FTS) catalyst, supported on a carbon nanofibers/carbon felt composite (Co/CNF/CF) was studied in situ at realistic conditions. The catalyst was monitored by Xray absorption spectroscopy (XAS), high-resolution X-ray powder diffraction (HR-XRPD) and Raman...... spectroscopy, while changes in the gas phase were observed by mass spectrometry (MS). Transmission electron microscopy (TEM) was also applied to characterise the catalyst. The catalyst has a bimodal particle size distribution and exhibits a high deactivation rate. During the in situ study the catalyst appears...... to reduce further at the induction period of FTS, while crystallite growth is been detected in the same period. At steady state FTS the amount of metallic Co is constant. A change in the volumetric flow towards higher conversions did not affect the degree of reduction or the crystallite size of the catalyst...

  11. Revisiting the electrochemical oxidation of ammonia on carbon-supported metal nanoparticle catalysts

    International Nuclear Information System (INIS)

    Li, Zhe-Fei; Wang, Yuxuan; Botte, Gerardine G.

    2017-01-01

    Highlights: • A procedure to pretreat electrocatalysts to study the ammonia oxidation is provided. • N ads and O/OH ads were identified as the major deactivation species that prevent ammonia oxidatoin. • The electrocatalytic activity, thermodynamics, and possible deactivation mechanisms for ammonia oxidation were elucidated. • The onset potential for ammonia oxidation is related to the hydrogen binding energy of the catalyst. • Ammonia electro-oxidation involves a complex decoupled electron and proton transfer process. - Abstract: The ammonia electro-oxidation reaction (AOR) has been studied due to its promising applications in ammonia electrolysis, wastewater remediation, direct ammonia fuel cells, and sensors. However, it is difficult to compare and analyze the reported electrocatalytic activity of AOR reliably, likely due to the variation in catalyst synthesis, electrode composition, electrode morphology, and testing protocol. In this paper, the electro-oxidation of ammonia on different carbon-supported precious metal nanoparticle catalysts was revisited. The effect of experimental conditions, electrochemical test parameters, electrocatalytic activity, thermodynamics, and possible deactivation mechanism of the catalysts were investigated. Pt/C catalyst possesses the highest electrocatalytic activity, while Ir/C and Rh/C show lower overpotential. The onset potential of the AOR is related to the hydrogen binding energy of the catalyst. N ads is one major cause of deactivation accompanied with the formation of surface O/OH ads at high potentials. The coulombic efficiency of N ads formation on Pt is about 1% initially and gradually decreases with reaction time. Increase in ammonia concentration leads to increase in current density, while increase in hydroxyl ions concentration can enhance the current density and reduce the overpotential simultaneously. The slopes of AOR onset potential and hydrogen adsorption/desorption potential of Pt/C as a function of p

  12. 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.

  13. Polystyrene Supported Al(OTf)3: an Environmentally Friendly Heterogeneous Catalyst for Friedel-Crafts Acylation of Aromatic Compounds

    International Nuclear Information System (INIS)

    Boroujeni, Kaveh Parvanak

    2010-01-01

    Stable and non-hygroscopic polystyrene supported aluminium triflate (Ps-Al(OTf) 3 ), which is prepared easily from cheap and commercially available compounds was found to be an environmentally friendly heterogeneous catalyst for Friedel-Crafts acylation of arenes using acid chlorides in the absence of solvent under mild reaction conditions. The catalyst can be reused up to five times after simple washing with dichloromethane

  14. Supported Vanadium Oxide Catalysts: Quantitative Spectroscopy, Preferential Adsorption of V^4+/5+, and Al2O3 Coating of Zeolite Y

    NARCIS (Netherlands)

    Catana, Gabriela; Rao, R.R.; Weckhuysen, B.M.; Voort, Pascal van der; Vansant, Etienne; Schoonheydt, R.A.

    1998-01-01

    A series of supported vanadium oxide catalysts were prepared by the incipient wetness method as a function of the support composition (Al2O3, SiO2, and USY), the metal oxide loading (0-1 wt %), and the impregnation salt (vanadyl sulfate and ammonium vanadate). These catalysts have been studied by

  15. 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.

  16. Efficient oxygen reduction reaction using ruthenium tetrakis(diaquaplatinum)octacarboxyphthalocyanine catalyst supported on MWCNT platform

    CSIR Research Space (South Africa)

    Maxakato, NW

    2011-02-01

    Full Text Available -1 Electroanalysis 2011, 23, No. 2, 325 ? 329 Efficient Oxygen Reduction Reaction Using Ruthenium Tetrakis(diaquaplatinum)Octacarboxyphthalocyanine Catalyst Supported on MWCNT Platform Nobanathi W. Maxakato,a Solomon A. Mamuru,a Kenneth I. Ozoemena*a, b a...

  17. 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.

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

    International Nuclear Information System (INIS)

    Hossain, Shahin; Park, Jihoon; Park, Minkyu; Jin, Myungjong

    2013-01-01

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

  19. Catalytic oxidation of albendazole using molybdenum supported on carbon nanotubes as catalyst

    International Nuclear Information System (INIS)

    Sun-Kou, Maria del Rosario; Vega Carrasco, Edgar R.; Picasso Escobar, Gino I.

    2013-01-01

    The catalytic oxidation reaction of the thioether group (-S-) in the structure to the drug albendazole (C 12 H 15 N 3 O 2 S) was studied in order to obtain a pharmacologically active molecule known as albendazole sulfoxide. With this purpose, three heterogeneous catalysts were prepared using molybdenum (Mo) as active phase and carbon nanotubes as a multiple-layer catalyst support. The incorporation of the active phase was performed by wet impregnation, with subsequent calcination for 4 hours at 400 o C. For the catalytic oxidation reaction was employed hydrogen peroxide-urea (H 2 NCONH 2 ·H 2 O 2 ) as oxidizing agent and methanol (CH 3 OH) as reaction medium. The textural and morphology characterization of carbon nanoparticles and catalysts was carried out by adsorption-desorption of N 2 (BET) and scanning electron microscopy (SEM). The identification and quantification of the reaction products were followed by Fourier transform infrared spectroscopy (FTIR) and high performance liquid chromatography (HPLC), respectively. With the yield, selectivity and conversion higher than 90% after 60 minutes of reaction, albendazole sulphoxide was obtained as major product of oxidation reaction. (author)

  20. A comparative study of alumina-supported Ni catalysts prepared by photodeposition and impregnation methods on the catalytic ozonation of 2,4-dichlorophenoxyacetic acid

    International Nuclear Information System (INIS)

    Rodríguez, Julia L.; Valenzuela, Miguel A.; Tiznado, Hugo; Poznyak, Tatiana; Chairez, Isaac; Magallanes, Diana

    2017-01-01

    The heterogeneous catalytic ozonation on unsupported and supported oxides has been successfully tested for the removal of several refractory compounds in aqueous solution. In this work, alumina-supported nickel catalysts prepared by photodeposition and impregnation methods were compared in the catalytic ozonation of 2,4-dichlorophenoxyacetic acid (2,4-D). The catalysts were characterized by high-resolution electron microscopy and X-ray photoelectron spectroscopy. The photochemical decomposition of Ni acetylacetonate to produce Ni(OH) 2 , NiO, and traces of Ni° deposited on alumina was achieved in the presence of benzophenone as a sensitizer. A similar surface composition was found with the impregnated catalyst after its reduction with hydrogen at 500 °C and exposed to ambient air. Results indicated a higher initial activity and maleic acid (byproduct) concentration with the photodeposited catalyst (1 wt% Ni) compared to the impregnated catalyst (3 wt% Ni). These findings suggest the use of the photodeposition method as a simple and reliable procedure for the preparation of supported metal oxide/metal catalysts under mild operating conditions.

  1. A comparative study of alumina-supported Ni catalysts prepared by photodeposition and impregnation methods on the catalytic ozonation of 2,4-dichlorophenoxyacetic acid

    Energy Technology Data Exchange (ETDEWEB)

    Rodríguez, Julia L., E-mail: ozliliana@yahoo.com.mx [Lab. Ing. Química Ambiental. ESIQIE–Instituto Politécnico Nacional (Mexico); Valenzuela, Miguel A. [Lab.Catálisis y Materiales. ESIQIE–Instituto Politécnico Nacional. Zacatenco (Mexico); Tiznado, Hugo [Centro de Nanociencias y Nanotecnología. CNyN Universidad Nacional Autónoma de México (Mexico); Poznyak, Tatiana [Lab. Ing. Química Ambiental. ESIQIE–Instituto Politécnico Nacional (Mexico); Chairez, Isaac [Departamento de Bioprocesos, UPIBI- Instituto Politécnico Nacional (Mexico); Magallanes, Diana [Lab. Ing. Química Ambiental. ESIQIE–Instituto Politécnico Nacional (Mexico)

    2017-02-15

    The heterogeneous catalytic ozonation on unsupported and supported oxides has been successfully tested for the removal of several refractory compounds in aqueous solution. In this work, alumina-supported nickel catalysts prepared by photodeposition and impregnation methods were compared in the catalytic ozonation of 2,4-dichlorophenoxyacetic acid (2,4-D). The catalysts were characterized by high-resolution electron microscopy and X-ray photoelectron spectroscopy. The photochemical decomposition of Ni acetylacetonate to produce Ni(OH){sub 2}, NiO, and traces of Ni° deposited on alumina was achieved in the presence of benzophenone as a sensitizer. A similar surface composition was found with the impregnated catalyst after its reduction with hydrogen at 500 °C and exposed to ambient air. Results indicated a higher initial activity and maleic acid (byproduct) concentration with the photodeposited catalyst (1 wt% Ni) compared to the impregnated catalyst (3 wt% Ni). These findings suggest the use of the photodeposition method as a simple and reliable procedure for the preparation of supported metal oxide/metal catalysts under mild operating conditions.

  2. Carbon-supported co-pyridine as non-platinum cathode catalyst for alkaline membrane fuel cells

    International Nuclear Information System (INIS)

    Qiao, Jinli; Xu, Li; Liu, Yuyu; Xu, Pan; Shi, Jingjing; Liu, Shiyao; Tian, Binglun

    2013-01-01

    Development of high-performance cost-effective electrocatalyts that can replace Pt catalyst have been a central theme in polymer electrolyte membrane fuel cells (PEMFCs) including direct methanol fuel cells (DMFCs). Here we show that carbon-supported pyridine–cobalt nanoparticles (CoPy/C) can generate a high catalytic activity toward the oxygen reduction reaction (ORR). The catalysts are synthesized using cobalt sulfate heptahydrate (CoSO 4 ·7H 2 O) and pyridine (Py) as the Co and N precursors via a solid state reaction by heat-treatment in an inert atmosphere at 800 °C. In particular, the ORR kinetics on these catalyst materials are evaluated using rotating disk electrode (RDE) technique in electrolytes of various KOH concentrations, ranging from 0.05 to 12 M. The Koutecky–Levich equation analyses indicate that the transferred electron number, n, per oxygen molecule on CoPy/C electrode depend on the low negative ovevrpotentials in low KOH concentrations, whereas in high KOH concentrations the values of n for oxygen reduction depend on the high negative overpotentials, and varies between 3.5 and 4.0. These catalysts exhibit the superior methanol tolerance to commercial 40%Pt/C catalyst, and the negative effect of high KOH concentration is much less for CoPy/C than for Pt/C, suggesting the promising utilization of CoPy/C as electrocatalysts for alkaline polymer electrolyte membrane fuel cells

  3. Palladium nanoparticles supported on fibrous-structured silica nanospheres (KCC-1): An efficient and selective catalyst for the transfer hydrogenation of alkenes

    KAUST Repository

    Qureshi, Ziyauddin; Sarawade, Pradip; Albert, Matthias; D'Elia, Valerio; Hedhili, Mohamed Nejib; Kö hler, Klaus; Basset, Jean-Marie

    2015-01-01

    An efficient palladium catalyst supported on fibrous silica nanospheres (KCC-1) has been developed for the hydrogenation of alkenes and α,β-unsaturated carbonyl compounds, providing excellent yields of the corresponding products with remarkable chemoselectivity. Comparison (high-resolution TEM, chemisorption) with analogous mesoporous (MCM-41, SBA-15) silica-supported Pd nanocatalysts prepared under identical conditions, demonstrates the advantage of employing the fibrous KCC-1 morphology versus traditional supports because it ensures superior accessibility of the catalytically active cores along with excellent Pd dispersion at high metal loading. This morphology ultimately leads to higher catalytic activity for the KCC-1-supported nanoparticles. The protocol developed for hydrogenation is advantageous and environmentally benign owing to the use of HCOOH as a source of hydrogen, water as a solvent, and because of efficient catalyst recyclability and durability. The recycled catalyst has been analyzed by XPS spectroscopy and TEM showing only minor changes in the oxidation state of Pd and in the morphology after the reaction, thus confirming the robustness of the catalyst.

  4. Synthesis and characterization of molybdenum catalysts supported on {gamma}-Al{sub 2}O{sub 3}-CeO{sub 2} composite oxides

    Energy Technology Data Exchange (ETDEWEB)

    Farooq, Muhammad; Ramli, Anita; Subbarao, Duvvuri [Department of Chemical EngineeringUniversiti Teknologi PETRONAS Bandar Seri Iskandar, 31750 Tronoh, Perak (Malaysia); Fundamental and Applied Sciences Department, Universiti Teknologi PETRONAS Bandar Seri Iskandar, 31750 Tronoh, Perak (Malaysia); Department of Chemical EngineeringUniversiti Teknologi PETRONAS Bandar Seri Iskandar, 31750 Tronoh, Perak (Malaysia)

    2012-09-26

    The physical and chemical properties of a catalyst play a vital role in various industrial applications. Molybdenum catalysts supported on {gamma}-Al{sub 2}O{sub 3} and {gamma}-Al{sub 2}O{sub 3}-CeO{sub 2} mixed oxides with varying loading of CeO{sub 2} (5, 10, 15, 20 wt% with respect to {gamma}-Al{sub 2}O{sub 3}) 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 CeO{sub 2} 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.

  5. Palladium nanoparticles supported on fibrous-structured silica nanospheres (KCC-1): An efficient and selective catalyst for the transfer hydrogenation of alkenes

    KAUST Repository

    Qureshi, Ziyauddin

    2015-01-09

    An efficient palladium catalyst supported on fibrous silica nanospheres (KCC-1) has been developed for the hydrogenation of alkenes and α,β-unsaturated carbonyl compounds, providing excellent yields of the corresponding products with remarkable chemoselectivity. Comparison (high-resolution TEM, chemisorption) with analogous mesoporous (MCM-41, SBA-15) silica-supported Pd nanocatalysts prepared under identical conditions, demonstrates the advantage of employing the fibrous KCC-1 morphology versus traditional supports because it ensures superior accessibility of the catalytically active cores along with excellent Pd dispersion at high metal loading. This morphology ultimately leads to higher catalytic activity for the KCC-1-supported nanoparticles. The protocol developed for hydrogenation is advantageous and environmentally benign owing to the use of HCOOH as a source of hydrogen, water as a solvent, and because of efficient catalyst recyclability and durability. The recycled catalyst has been analyzed by XPS spectroscopy and TEM showing only minor changes in the oxidation state of Pd and in the morphology after the reaction, thus confirming the robustness of the catalyst.

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

    DEFF Research Database (Denmark)

    Riisager, Anders; Fehrmann, Rasmus; Haumann, Marco

    2005-01-01

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

  7. Electrically conductive aluminum oxide thin film used as cobalt catalyst-support layer in vertically aligned carbon nanotube growth

    International Nuclear Information System (INIS)

    Azam, Mohd Asyadi; Ismail, Syahriza; Mohamad, Noraiham; Isomura, Kazuki; Shimoda, Tatsuya

    2015-01-01

    This paper will present the unique characteristics of aluminum oxide (Al–O) and cobalt catalyst included in aligned carbon nanotube (CNT) electrode system of energy storage device, namely electrochemical capacitor. Electrical conductivity and nanostructure of the thermally oxidized Al–O used as catalyst-support layer in vertically grown single-walled CNTs were studied. Al–O films were characterized by means of current–voltage measurement and high resolution transmission electron microscopy analysis. The Al–O support layer was found to be conductive, with a relatively low resistance and, approximately 20 nm film thickness of Al–O is suggested to be too thin to form insulating barrier. The scanning TEM—annular dark field analysis confirmed that the nanosized cobalt catalyst particles distributed on Al–O surfaces and also embedded inside the Al–O film structure. (paper)

  8. Vapor phase carbonylation of dimethyl ether and methyl acetate with supported transition metal catalysts

    International Nuclear Information System (INIS)

    Shikada, T.; Fujimoto, K.; Tominaga, H.O.

    1986-01-01

    The synthesis of acetic acid (AcOH) from methanol (MeOH) and carbon monoxide has been performed industrially in the liquid phase using a rhodium complex catalyst and an iodide promoter. The selectivity to AcOH is more than 99% under mild conditions (175 0 C, 28 atm). The homogeneous rhodium catalyst has been also effective for the synthesis of acetic anhydride (Ac 2 O) by carbonylation of dimethyl ether (DME) or methyl acetate (AcOMe). However, rhodium is one of the most expensive metals and its proved reserves are quite limited. It is highly desired, therefore, to develop a new catalyst as a substitute for rhodium. The authors have already reported that nickel supported on active carbon exhibits an excellent activity for the vapor phase carbonylation of MeOh in the presence of iodide promoter and under moderately pressurized conditions. In addition, corrosive attack on reactors by iodide compounds is expected to be negligible in the vapor phase system. In the present work, vapor phase carbonylation of DME and AcOMe on nickel-active carbon (Ni/A.C.) and molybdenum-active carbon (Mo/A.C.) catalysts was studied

  9. Session 6: Liquid-phase chloro-benzene hydrogenolysis over alkali-doped zirconia supported palladium catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Aramendia, M.A.; Borau, V.; Jimenez, C.; Marinas, A.; Marinas, J.M.; Moreno, J.M.; Ruiz, J.R.; Urbano, F.J. [University of Cordoba. Marie Curie Building, Dept. of Organic Chemistry (Spain)

    2004-07-01

    Chlorinated hydrocarbons constitute one of the most important kind of organic pollutants due to their environmental impact and noxious effects. Catalytic hydro-dehalogenation is now emerging as a promising non-destructive alternative technology whereby the chlorinated waste is converted to products with a commercial value. It is simple, safe, effective, and it ensures, in many instances, the regeneration of the initial raw material. One of the main problems of catalytic hydro-dehalogenation arise from the deactivating effect of the hydrogen halide released as by product. This can be surpassed by, for example, adding a base, such as NaOH, or modification of the catalyst in order to neutralize the hydrogen halide released. In conclusion, the alkali modification of the zirconia supported catalysts did not enhance the catalytic activity in comparison to the undoped Pd/ZrO{sub 2}. Moreover, the lithium doped catalyst exhibits very poor results in initial rate and final chloro-benzene conversion. This could be related to the reduction in BET surface area caused by the doping together with a lower enhancement of the surface basicity of the doped catalysts. (authors)

  10. High-temperature catalytic reforming of n-hexane over supported and core-shell Pt nanoparticle catalysts: role of oxide-metal interface and thermal stability.

    Science.gov (United States)

    An, Kwangjin; Zhang, Qiao; Alayoglu, Selim; Musselwhite, Nathan; Shin, Jae-Youn; Somorjai, Gabor A

    2014-08-13

    Designing catalysts with high thermal stability and resistance to deactivation while simultaneously maintaining their catalytic activity and selectivity is of key importance in high-temperature reforming reactions. We prepared Pt nanoparticle catalysts supported on either mesoporous SiO2 or TiO2. Sandwich-type Pt core@shell catalysts (SiO2@Pt@SiO2 and SiO2@Pt@TiO2) were also synthesized from Pt nanoparticles deposited on SiO2 spheres, which were encapsulated by either mesoporous SiO2 or TiO2 shells. n-Hexane reforming was carried out over these four catalysts at 240-500 °C with a hexane/H2 ratio of 1:5 to investigate thermal stability and the role of the support. For the production of high-octane gasoline, branched C6 isomers are more highly desired than other cyclic, aromatic, and cracking products. Over Pt/TiO2 catalyst, production of 2-methylpentane and 3-methylpentane via isomerization was increased selectively up to 420 °C by charge transfer at Pt-TiO2 interfaces, as compared to Pt/SiO2. When thermal stability was compared between supported catalysts and sandwich-type core@shell catalysts, the Pt/SiO2 catalyst suffered sintering above 400 °C, whereas the SiO2@Pt@SiO2 catalyst preserved the Pt nanoparticle size and shape up to 500 °C. The SiO2@Pt@TiO2 catalyst led to Pt nanoparticle sintering due to incomplete protection of the TiO2 shells during the reaction at 500 °C. Interestingly, over the Pt/TiO2 catalyst, the average size of Pt nanoparticles was maintained even after 500 °C without sintering. In situ ambient pressure X-ray photoelectron spectroscopy demonstrated that the Pt/TiO2 catalyst did not exhibit TiO2 overgrowth on the Pt surface or deactivation by Pt sintering up to 600 °C. The extraordinarily high stability of the Pt/TiO2 catalyst promoted high reaction rates (2.0 μmol · g(-1) · s(-1)), which was 8 times greater than other catalysts and high isomer selectivity (53.0% of C6 isomers at 440 °C). By the strong metal-support interaction

  11. Manufacture of highly loaded silica-supported cobalt Fischer–Tropsch catalysts from a metal organic framework

    KAUST Repository

    Sun, Xiaohui; Suarez, Alma I. Olivos; Meijerink, Mark; van Deelen, Tom; Ould-Chikh, Samy; Zečević, Jovana; de Jong, Krijn P.; Kapteijn, Freek; Gascon, Jorge

    2017-01-01

    The development of synthetic protocols for the preparation of highly loaded metal nanoparticle-supported catalysts has received a great deal of attention over the last few decades. Independently controlling metal loading, nanoparticle size

  12. Enhancing Pt-Ni/CeO2 performances for ethanol reforming by catalyst supporting on high surface silica

    NARCIS (Netherlands)

    Palma, V.; Ruocco, C; Meloni, E.; Gallucci, F.; Ricca, A.

    2018-01-01

    In this paper, bimetallic Pt-Ni/CeO2 catalysts supported over mesoporous silica were employed for ethanol reforming in the low-temperature range. In particular, catalyst behaviour was investigated under a H2O/C2H5OH/N2 as well as H2O/C2H5OH/AIR mixture between 300 and 600 °C at different space

  13. Synthesis of carbon-supported nickel catalysts for the dry reforming of CH{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Fidalgo, B.; Zubizarreta, L.; Bermudez, J.M.; Arenillas, A.; Menendez, J.A. [Instituto Nacional del Carbon, CSIC, Apartado 73, 33080 Oviedo (Spain)

    2010-07-15

    A series of carbon-based nickel (Ni) catalysts was prepared in order to investigate the effect of the preparation method on the dispersion of Ni and its final catalytic activity in the dry reforming of methane, i.e. CH{sub 4} + CO{sub 2} 2H{sub 2} + 2CO. Three parameters were studied: (i) the influence of the surface chemistry of the carbon used as support; (ii) the method of drying (conventional vs. microwave drying); and, (iii) the temperature of the reduction stage. In order to study the role of the surface chemistry of the commercial activated carbon used as support, the active carbon was tested as received and oxidized. Although a better Ni dispersion was achieved over the oxidized support, the conversions were much lower. It was also found that microwave drying offers various advantages over conventional drying, the main one being that less time is required to prepare the catalyst. Two reduction temperatures were used (300 and 500 C), being found that it is necessary to adjust this parameter to prevent the Ni particles from sintering. (author)

  14. 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)

  15. Electrocatalytic properties of carbon-supported Pt-Ru catalysts with the high alloying degree for formic acid electrooxidation

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yu.; Zhou, Yiming; Tang, Yawen; Lu, Tianhong [College of Chemistry and Environmental Science, Nanjing Normal University, Nanjing 210097 (China)

    2010-07-01

    A series of carbon-supported bimetallic Pt-Ru catalysts with high alloying degree and different Pt/Ru atomic ratio have been prepared by a chemical reduction method in the H{sub 2}O/ethanol/tetrahydrofuran (THF) mixture solvent. The structural and electronic properties of catalysts are characterized using X-ray reflection (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM). The electrooxidation of formic acid on these Pt-Ru nanoparticles are investigated by using cyclic voltammetry, chronoamperometry and CO-stripping measurements. The results of electrochemical measurements illustrate that the alloying degree and Pt/Ru atomic ratio of Pt-Ru catalyst play an important role in the electrocatalytic activity of the Pt-Ru/C catalyst for formic acid electrooxidation due to the bifunctional mechanism and the electronic effect. Since formic acid is an intermediate in the methanol electrooxidation on Pt electrode in acidic electrolyte, the observation provides an additional fundamental understanding of the structure-activity relationship of Pt-Ru catalyst for methanol electrooxidation. (author)

  16. Influence of Synthesis pH on Textural Properties of Carbon Xerogels as Supports for Pt/CXs Catalysts for Direct Methanol Fuel Cells

    Directory of Open Access Journals (Sweden)

    C. Alegre

    2012-01-01

    Full Text Available Carbon xerogels (CXs have been prepared by polycondensation of resorcinol and formaldehyde. Two synthesis pHs were studied in order to evaluate its influence on the electrochemical behaviour of Pt catalysts supported on previous carbon xerogels, synthesized by conventional impregnation method. Catalysts were also synthesized over a commercial carbon black (Vulcan-XC-72R for comparison purposes. Characterization techniques included nitrogen physisorption, scanning electron microscopy, and X-ray diffraction. Catalysts electrochemical activity towards the oxidation of carbon monoxide and methanol was studied by cyclic voltammetry and chronoamperometry to establish the effect of the carbon support on the catalysts performance. Commercial Pt/C catalyst (E-TEK was analyzed for comparison purposes. It was observed that the more developed and mesopore-enriched porous structure of the carbon xerogel synthesized at a higher initial pH resulted in an optimal utilization of the active phase and in an enhanced and promising catalytic activity in the electrooxidation of methanol, in comparison with commercial catalysts.

  17. A possible highly active supported Ni dimer catalyst for O{sub 2} dissociation: A first-principles study

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Shan [College of Physics and Materials Science, Henan Normal University, Xinxiang, Henan 453007 (China); Zhang, Yanxing, E-mail: 2016025@htu.edu.cn [College of Physics and Materials Science, Henan Normal University, Xinxiang, Henan 453007 (China); Zhang, Xilin; Mao, Jianjun [College of Physics and Materials Science, Henan Normal University, Xinxiang, Henan 453007 (China); Yang, Zongxian, E-mail: yzx@henannu.edu.cn [College of Physics and Materials Science, Henan Normal University, Xinxiang, Henan 453007 (China); Collaborative Innovation Center of Nano Functional Materials and Applications, Henan Province (China)

    2017-04-30

    Graphical abstract: The minimum energy paths (MEPs) for the dissociation process of O{sub 2} on the surfaces of bare YSZ (111) and Ni{sub n}/YSZ (111) (n = 1, 2 and 3). - Highlights: • The catalytic activity of supported metal catalysts is closely related to the size of metal particles. • The dissociation of O{sub 2} on the YSZ (111) surface is largely enhanced by the supported Ni cluster. • The supported Ni dimer is predicted to be the smallest Ni cluster needed for efficient O{sub 2} dissociation. • The results would provide an important reference to improve the activity and efficiency of the Ni/YSZ(111) nanocomposite catalysts in cost-effective materials. - Abstract: The adsorption and dissociation of O{sub 2} on the supported small nickel clusters with one-, two-, three-Ni atoms on yttria-stabilized zirconia (YSZ) (111) surfaces, as well as those on the bare YSZ(111) and Ni(111) surfaces are comparatively studied using ab initio density functional theory calculations. It is found that the dissociation of O{sub 2} on the YSZ(111) surface is largely enhanced by the supported Ni dimer, which is predicted to be the smallest Ni cluster needed for efficient O{sub 2} dissociation. The results would provide an important reference to improve the activity and efficiency of the Ni/YSZ(111) nanocomposite catalysts in cost-effective materials.

  18. Continuous fixed-bed gas-phase hydroformylation using supported ionic liquid-phase (SILP) Rh catalysts

    DEFF Research Database (Denmark)

    Riisager, Anders; Wasserscheid, Peter; Van Hal, R.

    2003-01-01

    Continuous flow gas-phase hydroformylation of propene was performed using novel supported ionic liquid-phase (SILP) catalysts containing immobilized Rh complexes of the biphosphine ligand sulfoxantphos in the ionic liquids 1-n-butyl-3-methylimidazolium hexafluorophosphate and halogen-free 1-n-butyl...

  19. Selective nano alumina supported vanadium oxide catalysts for oxidative dehydrogenation of ethylbenzene to styrene using CO2 as soft oxidant

    Directory of Open Access Journals (Sweden)

    A.M. Elfadly

    2013-12-01

    Full Text Available Nano alumina-supported V2O5 catalysts with different loadings have been tested for the dehydrogenation of ethylbenzene with CO2 as an oxidant. High surface area nano-alumina was prepared and used as support for V2O5 as the catalyst. The catalysts were synthesized by impregnation techniques followed by calcinations and microwave treatment, denoted as V2O5/γ-Al2O3-C and V2O5/γ-Al2O3-MW, respectively. The V2O5 loading was varied on nano-alumina from 5 to 30 wt%. The support and catalysts were characterized by X-ray diffraction (XRD, Barett–Joyner–Halenda (BJH pore-size distribution, N2-adsorption isotherms, Fourier transform infrared (FT-IR, scanning electron microscopy (SEM, transmission electron microscopy (TEM and temperature programed desorption (TPD-NH3. The characterization results indicated that V2O5 is highly dispersed on alumina up to 30%-V2O5/γ-Al2O3-MW prepared by MW method. The TPD studies indicated that there are significant differences in acid amount and strength for V2O5/γ-Al2O3-C and V2O5/γ-Al2O3-MW-catalysts. The catalytic activity of the prepared catalysts was evaluated in the temperature range 450–600 °C in relation to the physicochemical properties and surface acidity. The results revealed that optimum catalytic activity and selectivity (∼100% toward styrene production were obtained using 10% V2O5/γ-Al2O3-MW catalyst treated with microwave.

  20. Development of Molecular Catalysts to Bridge the Gap between Heterogeneous and Homogeneous Catalysts

    Science.gov (United States)

    Ye, Rong

    Catalysts, heterogeneous, homogeneous, and enzymatic, are comprised of nanometer-sized inorganic and/or organic components. They share molecular factors including charge, coordination, interatomic distance, bonding, and orientation of catalytically active atoms. By controlling the governing catalytic components and molecular factors, catalytic processes of a multichannel and multiproduct nature could be run in all three catalytic platforms to create unique end-products. Unifying the fields of catalysis is the key to achieving the goal of 100% selectivity in catalysis. Recyclable catalysts, especially those that display selective reactivity, are vital for the development of sustainable chemical processes. Among available catalyst platforms, heterogeneous catalysts are particularly well-disposed toward separation from the reaction mixture via filtration methods, which renders them readily recyclable. Furthermore, heterogeneous catalysts offer numerous handles - some without homogeneous analogues - for performance and selectivity optimization. These handles include nanoparticle size, pore profile of porous supports, surface ligands and interface with oxide supports, and flow rate through a solid catalyst bed. Despite these available handles, however, conventional heterogeneous catalysts are themselves often structurally heterogeneous compared to homogeneous catalysts, which complicates efforts to optimize and expand the scope of their reactivity and selectivity. Ongoing efforts are aimed to address the above challenge by heterogenizing homogeneous catalysts, which can be defined as the modification of homogeneous catalysts to render them in a separable (solid) phase from the starting materials and products. Specifically, we grow the small nanoclusters in dendrimers, a class of uniform polymers with the connectivity of fractal trees and generally radial symmetry. Thanks to their dense multivalency, shape persistence and structural uniformity, dendrimers have proven to

  1. Reactivity of Aryl Halides for Reductive Dehalogenation in (Seawater Using Polymer-Supported Terpyridine Palladium Catalyst

    Directory of Open Access Journals (Sweden)

    Toshimasa Suzuka

    2015-05-01

    Full Text Available A polymer-supported terpyridine palladium complex was prepared. The complex was found to promote hydrodechlorination of aryl chlorides with potassium formate in seawater. Generally, reductive cleavage of aryl chlorides using transition metal catalysts is more difficult than that of aryl bromides and iodides (reactivity: I > Br > Cl; however, the results obtained did not follow the general trend. Therefore, we investigated the reaction inhibition agents and found a method to remove these inhibitors. The polymeric catalysts showed high catalytic activity and high reusability for transfer reduction in seawater.

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

    Indian Academy of Sciences (India)

    YONGZHOU YE

    Their performances for the selective catalytic reduction (SCR) of NOx with NH3 were evaluated. ... catalysts have received considerable attention.2,3 More- over, catalysts ..... zeolite channels or causing agglomeration on the cat- alyst surface ...

  3. Bimetallic Ag-Pt Sub-nanometer Supported Clusters as Highly Efficient and Robust Oxidation Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Negreiros, Fabio R. [CNR-ICCOM & IPCF, Consiglio Nazionale delle Ricerche, Pisa Italy; Halder, Avik [Materials Science Division, Argonne National Laboratory, Lemont IL USA; Yin, Chunrong [Materials Science Division, Argonne National Laboratory, Lemont IL USA; Singh, Akansha [Harish-Chandra Research Institute, HBNI, Chhatnag Road Jhunsi Allahabad 211019 India; Barcaro, Giovanni [CNR-ICCOM & IPCF, Consiglio Nazionale delle Ricerche, Pisa Italy; Sementa, Luca [CNR-ICCOM & IPCF, Consiglio Nazionale delle Ricerche, Pisa Italy; Tyo, Eric C. [Materials Science Division, Argonne National Laboratory, Lemont IL USA; Pellin, Michael J. [Materials Science Division, Argonne National Laboratory, Lemont IL USA; Bartling, Stephan [Institut für Physik, Universität Rostock, Rostock Germany; Meiwes-Broer, Karl-Heinz [Institut für Physik, Universität Rostock, Rostock Germany; Seifert, Sönke [X-ray Science Division, Argonne National Laboratory, Lemont IL USA; Sen, Prasenjit [Harish-Chandra Research Institute, HBNI, Chhatnag Road Jhunsi Allahabad 211019 India; Nigam, Sandeep [Chemistry Division, Bhabha Atomic Research Centre, Trombay Mumbai- 400 085 India; Majumder, Chiranjib [Chemistry Division, Bhabha Atomic Research Centre, Trombay Mumbai- 400 085 India; Fukui, Nobuyuki [East Tokyo Laboratory, Genesis Research Institute, Inc., Ichikawa Chiba 272-0001 Japan; Yasumatsu, Hisato [Cluster Research Laboratory, Toyota Technological Institute: in, East Tokyo Laboratory, Genesis Research Institute, Inc. Ichikawa, Chiba 272-0001 Japan; Vajda, Stefan [Materials Science Division, Argonne National Laboratory, Lemont IL USA; Nanoscience and Technology Division, Argonne National Laboratory, Lemont IL USA; Institute for Molecular Engineering, University of Chicago, Chicago IL USA; Fortunelli, Alessandro [CNR-ICCOM & IPCF, Consiglio Nazionale delle Ricerche, Pisa Italy; Materials and Process Simulation Center, California Institute of Technology, Pasadena CA USA

    2017-12-29

    A combined experimental and theoretical investigation of Ag-Pt sub-nanometer clusters as heterogeneous catalysts in the CO -> CO2 reaction (COox) is presented. Ag9Pt2 and Ag9Pt3 clusters are size-selected in the gas phase, deposited on an ultrathin amorphous alumina support, and tested as catalysts experimentally under realistic conditions and by first-principles simulations at realistic coverage. Insitu GISAXS/TPRx demonstrates that the clusters do not sinter or deactivate even after prolonged exposure to reactants at high temperature, and present comparable, extremely high COox catalytic efficiency. Such high activity and stability are ascribed to a synergic role of Ag and Pt in ultranano-aggregates, in which Pt anchors the clusters to the support and binds and activates two CO molecules, while Ag binds and activates O-2, and Ag/Pt surface proximity disfavors poisoning by CO or oxidized species.

  4. Hydrothermal Synthesis of MoO2 and Supported MoO2 Cata-lysts for Oxidative Desulfurization of Dibenzothiophene

    Institute of Scientific and Technical Information of China (English)

    Wang Danhong; Zhang Jianyong; Liu Ni; Zhao Xin; Zhang Minghui

    2014-01-01

    A novel method for obtaining spherical MoO2 nanoparticles and SiO2-Al2O3 supported MoO2 by hydrothermal reduction of Mo (VI) species was studied. The obtained MoO2 catalysts show very high catalytic activity in the oxidative desulfurization (ODS) process. The effect of hydrothermal temperature and crystallization temperature on ODS activity was investigated. The ODS activity of supported MoO2 catalysts with various MoO2 contents were also investigated. The mecha-nism for formation of MoO2 involving oxalic acid was proposed.

  5. Boron-containing catalysts for dry reforming of methane to synthesis gas

    KAUST Repository

    Takanabe, Kazuhiro

    2018-01-04

    The present invention uses a cobalt catalyst for carbon dioxide reforming of lower alkanes to synthesis gas having a cobalt catalyst on an oxide support where the supported cobalt catalyst has been modified with a boron precursor. The boron-treated cobalt catalyst systems as described herein show significant increases in the conversion of CH4 and CO2 during the dry reforming of methane (DRM) reaction as compared to traditional catalysts. Described herein are supported catalysts and methods of using the catalysts for the dry reforming of methane to synthesis gas, with the supported catalysts in the present invention include a boron-treated cobalt catalyst disposed on an oxide support. Also described herein are processes for preparing the supported catalysts.

  6. Tungsten carbide/porous carbon composite as superior support for platinum catalyst toward methanol electro-oxidation

    International Nuclear Information System (INIS)

    Jiang, Liming; Fu, Honggang; Wang, Lei; Mu, Guang; Jiang, Baojiang; Zhou, Wei; Wang, Ruihong

    2014-01-01

    Graphical abstract: The WC nanoparticles are well dispersed in the carbon matrix. The size of WC nanoparticles is about 30 nm. It can be concluded that tungsten carbide and carbon composite was successfully prepared by the present synthesis conditions. - Highlights: • The WC/PC composite with high specific surface area was prepared by a simple way. • The Pt/WC/PC catalyst has superior performance toward methanol electro-oxidation. • The current density for methanol electro-oxidation is as high as 595.93 A g −1 Pt. • The Pt/WC/PC catalyst shows better durability and stronger CO electro-oxidation. • The performance of Pt/WC/PC is superior to the commercial Pt/C (JM) catalyst. - Abstract: Tungsten carbide/porous carbon (WC/PC) composites have been successfully synthesized through a surfactant assisted evaporation-induced-assembly method, followed by a thermal treatment process. In particular, WC/PC-35-1000 composite with tungsten content of 35% synthesized at the carbonized temperature of 1000 °C, exhibited a specific surface area (S BET ) of 457.92 m 2 g −1 . After loading Pt nanoparticles (NPs), the obtained Pt/WC/PC-35-1000 catalyst exhibits the highest unit mass electroactivity (595.93 A g −1 Pt) toward methanol electro-oxidation, which is about 2.6 times as that of the commercial Pt/C (JM) catalyst. Furthermore, the Pt/WC/PC-35-1000 catalyst displays much stronger resistance to CO poisoning and better durability toward methanol electrooxidation compared with the commercial Pt/C (JM) catalyst. The high electrocatalytic activity, strong poison-resistivity and good stability of Pt/WC/PC-35-1000 catalyst are attributed to the porous structures and high specific surface area of WC/PC support could facilitate the rapid mass transportation. Moreover, synergistic effect between WC and Pt NPs is favorable to the higher catalytic performance

  7. Support effects on adsorption and catalytic activation of O2 in single atom iron catalysts with graphene-based substrates.

    Science.gov (United States)

    Gao, Zheng-Yang; Yang, Wei-Jie; Ding, Xun-Lei; Lv, Gang; Yan, Wei-Ping

    2018-03-07

    The adsorption and catalytic activation of O 2 on single atom iron catalysts with graphene-based substrates were investigated systematically by density functional theory calculation. It is found that the support effects of graphene-based substrates have a significant influence on the stability of the single atom catalysts, the adsorption configuration, the electron transfer mechanism, the adsorption energy and the energy barrier. The differences in the stable adsorption configuration of O 2 on single atom iron catalysts with different graphene-based substrates can be well understood by the symmetrical matching principle based on frontier molecular orbital analysis. There are two different mechanisms of electron transfer, in which the Fe atom acts as the electron donor in single vacancy graphene-based substrates while the Fe atom mainly acts as the bridge for electron transfer in double vacancy graphene-based substrates. The Fermi softness and work function are good descriptors of the adsorption energy and they can well reveal the relationship between electronic structure and adsorption energy. This single atom iron catalyst with single vacancy graphene modified by three nitrogen atoms is a promising non-noble metal single atom catalyst in the adsorption and catalytic oxidation of O 2 . Furthermore, the findings can lay the foundation for the further study of graphene-based support effects and provide a guideline for the development and design of new non-noble-metal single atom catalysts.

  8. Cobalt Oxide Catalysts on Commercial Supports for N2O Decomposition.

    Czech Academy of Sciences Publication Activity Database

    Klegová, A.; Pacultová, K.; Fridrichová, D.; Volodarskaja, A.; Kovanda, J.; Jirátová, Květa

    2017-01-01

    Roč. 40, č. 5 (2017), s. 981-990 ISSN 0930-7516. [International Congress of Chemical and Process Engineering CHISA 2016 /22./ and the 19th Conference PRES 2016. Prague, 27.08.2016-31.08.2016] R&D Projects: GA ČR GA14-13750S Institutional support: RVO:67985858 Keywords : N2O decomposition * cobalt oxide * shaped catalyst Subject RIV: CI - Industrial Chemistry, Chemical Engineering OBOR OECD: Chemical process engineering Impact factor: 2.051, year: 2016

  9. Pt Catalyst Supported within TiO2 Mesoporous Films for Oxygen Reduction Reaction

    International Nuclear Information System (INIS)

    Huang, Dekang; Zhang, Bingyan; Bai, Jie; Zhang, Yibo; Wittstock, Gunther; Wang, Mingkui; Shen, Yan

    2014-01-01

    In this study, dispersed Pt nanoparticles into mesoporous TiO 2 thin films are fabricated by a facile electrochemical deposition method as electro-catalysts for oxygen reduction reaction. The mesoporous TiO 2 thin films coated on the fluorine-doped tin oxide glass by screen printing allow a facile transport of reactants and products. The structural properties of the resulted Pt/TiO 2 electrode are evaluated by field emission scanning electron microscopy, energy dispersive X-ray spectrometry, X-ray diffraction, and X-ray photoelectron spectroscopy. Cyclic voltammetry measurements are performed to study the electrochemical properties of the Pt/TiO 2 electrode. Further study demonstrates the stability of the Pt catalyst supported within TiO 2 mesoporous films for the oxygen reduction reaction

  10. Polymer-modified copper catalysts on carbon-containing support for reactions of H2O2 decomposition and cyclohexane oxidation

    Directory of Open Access Journals (Sweden)

    S. Auezkhanova

    2012-12-01

    Full Text Available Polymer-copper catalysts supported on a carbon-containing sorbent(CS, obtained by rice husk pyrolysis have been studied in the reactions of hydrogen peroxide decomposition and cyclohexane oxidation by hydrogen peroxide at 40°C and atmospheric pressure. The effect of the polymer nature on the activity of the developed catalysts have been shown. Polyhexamethyleneguanidine (PHMG was an optimal modifier for the developed catalysts. The calculated number of catalytic cycles (TON for 7% Cu-PGMG/CS was 450.

  11. Fischer-Tropsch Synthesis over Iron Manganese Catalysts: Effect of Preparation and Operating Conditions on Catalyst Performance

    Directory of Open Access Journals (Sweden)

    Ali A. Mirzaei

    2009-01-01

    molar basis which is the most active catalyst for the conversion of synthesis gas to light olefins. The effects of different promoters and supports with loading of optimum support on the catalytic performance of catalysts are also studied. It was found that the catalyst containing 50%Fe/50%Mn/5 wt.%Al2O3 is an optimum-modified catalyst. The catalytic performance of optimal catalyst has been studied in operation conditions such as a range of reaction temperatures, H2/CO molar feed ratios and a range of total pressures. Characterization of both precursors and calcined catalysts is carried out by powder X-ray diffraction (XRD, scanning electron microscopy (SEM, BET specific surface area and thermal analysis methods such as TGA and DSC.

  12. Silica-supported sulfonic acids as recyclable catalyst for esterification of levulinic acid with stoichiometric amounts of alcohols

    Directory of Open Access Journals (Sweden)

    Raimondo Maggi

    2016-10-01

    Full Text Available Converting biomass into value-added chemicals holds the key to sustainable long-term carbon resource management. In this context, levulinic acid, which is easily obtained from cellulose, is valuable since it can be transformed into a variety of industrially relevant fine chemicals. Here we present a simple protocol for the selective esterification of levulinic acid using solid acid catalysts. Silica supported sulfonic acid catalysts operate under mild conditions and give good conversion and selectivity with stoichiometric amounts of alcohols. The sulfonic acid groups are tethered to the support using organic tethers. These tethers may help in preventing the deactivation of the active sites in the presence of water.

  13. Performance characterization of CNTs and γ-Al2O3 supported cobalt catalysts in Fischer-Tropsch reaction

    International Nuclear Information System (INIS)

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

    2014-01-01

    Catalysts were prepared via a wet impregnation method. Different physicochemical properties of the samples were revealed by transmission electron microscope (TEM), temperature programmed reduction (H 2 -TPR) and carbon dioxide desorption (CO 2 -desorption). Fischer-Tropsch reaction (FTS) was carried out in a fixed-bed microreactor at 220°C and 1 atm, with H 2 /CO = 2v/v and space velocity, SV of 12L/g.h for 5 h. Various characterization techniques revealed that there was a stronger interaction between Co and Al 2 O 3 support compared to that of CNTs support. CNTs support increased the reducibility and decreased Co particle size. A significant increase in % CO conversion and FTS reaction rate was observed over CNTs support compared to that of Co/Al 2 O 3 . Co/CNTs resulted in higher C 5+ hydrocarbons selectivity compared to that of Co/Al 2 O 3 catalyst. CNTs are a better support for Co compared to Al 2 O 3

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

    International Nuclear Information System (INIS)

    Kang, Shuai; Shen, Pei Kang

    2015-01-01

    Graphical Abstract: A porous α-Fe 2 O 3 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-Fe 2 O 3 supported Pt catalyst has been synthesized for the first time. •With the addition of α-Fe 2 O 3 , 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-Fe 2 O 3 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-Fe 2 O 3 particles are concentrated to 2.46 nm in a mesooporous scale. Its electrochemical performance is tested. The ethanol oxidation current of the Pt/Fe 2 O 3 catalsyt obviously improves under illumination, compared with that in the dark, during the optical switching operation. Moreover, with the addition of α-Fe 2 O 3 , 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

  15. Catalytic upgrading of oleic acid into biofuel using Mo modified zeolite supported Ni oxalate catalyst functionalized with fluoride ion

    International Nuclear Information System (INIS)

    Ayodele, O.B.; Abbas, Hazzim F.; Daud, Wan Mohd Ashri Wan

    2014-01-01

    Highlights: • Modification of zeolite with freshly prepared molybdenum oxalate. • Functionalization of Ni oxalate with HF and incorporation into Mo modified zeolite. • Characterization of synthesized Mo modified zeolite supported Ni oxalate catalyst. • Deoxygenation of oleic acid with the synthesized zeolite supported catalyst. • Reusability study on the synthesized zeolite supported catalyst. - Abstract: In this study, fluoride ion functionalized nickel oxalate supported on molybdenum modified zeolite (NiMoFOx/Zeol) catalyst was synthesized, characterized and tested on the hydrodeoxygenation (HDO) of oleic acid (OA) into paraffinic fuel. The NiMoFOx/Zeol characterization results confirmed the presence of both Ni and Mo as well as the formation of NiMoO 4 which is a highly HDO reactive specie at 2θ value of 43.6° according to the XRD result. NiMoFOx/Zeol also showed loss in crystallinity and reduction in the average particle size leading to increase in the pore volume and specific surface area due to the combined effects of fluoride ion presence, oxalic acid functionalization and calcination. The effect of temperature, pressure and NiMoFOx/Zeol loading studied showed that initial increase in their values increased the yield of the target fractions until some points where reduction was observed. The best observed experimental conditions to hydrodeoxygenate 40 g (∼45 mL) of OA into 75% n-C 18 and 23% i-C 18 were 360 °C, 30 mg NiMoFOx/Zeol loading and 20 bar using 100 mL H 2 /min. The presence of i-C 18 was due to the functionalization of the catalyst with fluoride ion. The catalyst reusability result displayed excellent qualities with marginal loss of only 2% in activity after third reuse due to the improved synthesis protocol that employed organometallic precursor. The results are strongly encouraging for further studies toward industrialization of HDO process

  16. Catalysts with Cu base supported in mixed oxides to generate H2: reformed of methanol in oxidant atmosphere

    International Nuclear Information System (INIS)

    Aguila M, M.M.; Perez H, R.; Rodriguez L, V.

    2006-01-01

    In this work, the characterization of Cu supported in CeO 2 -ZrO 2 , for to generate H 2 starting from the one reformed of methanol with water vapor and oxygen is presented. The sol-gel technique and classic impregnation for the obtaining of the supports and catalysts respectively were used. The materials were characterized by XRD, SEM, adsorption- desorption of N 2 and TPR. The catalytic materials presented crystalline phases associated with the zircon (tetragonal and monoclinic phase) and the ceria (cubic phase) depending on the CeO 2 /ZrO 2 relationship. The morphology of the catalysts was analyzed by SEM being observed semispheric particles for the rich materials in ZrO 2 and added planars in the rich materials in CeO 2 . The ceria addition to the zircon favors the specific area of the mixed oxides CeO 2 -ZrO 2 and it promotes the reducibility of the copper oxide at low temperatures. The rich catalysts in ceria also showed high activity in the methanol transformation and bigger selectivity toward the production of H 2 . This result is associated with the presence of copper species that decrease to low temperature present in the rich catalysts in ceria and that they are not present in the rich catalysts in zircon. (Author)

  17. Synthesis of a highly active carbon-supported Ir-V/C catalyst for the hydrogen oxidation reaction in PEMFC

    International Nuclear Information System (INIS)

    Li Bing; Qiao Jinli; Yang Daijun; Zheng Junsheng; Ma Jianxin; Zhang Jiujun; Wang Haijiang

    2009-01-01

    The active, carbon-supported Ir and Ir-V nanoclusters with well-controlled particle size, dispersity, and composition uniformity, have been synthesized via an ethylene glycol method using IrCl 3 and NH 4 VO 3 as the Ir and V precursors. The nanostructured catalysts were characterized by X-ray diffraction and high-resolution transmission electron microscopy. The catalytic activities of these carbon-supported nanoclusters were screened by applying on-line cyclic voltammetry and electrochemical impedance spectroscopy techniques, which were used to characterize the electrochemical properties of fuel cells using several anode Ir/C and Ir-V/C catalysts. It was found that Ir/C and Ir-V/C catalysts affect the performance of electrocatalysts significantly based on the discharge characteristics of the fuel cell. The catalyst Ir-V/C at 40 wt.% displayed the highest catalytic activity to hydrogen oxidation reaction and, therefore, high cell performance is achieved which results in a maximum power density of 563 mW cm -2 at 0.512 V and 70 deg. C in a real H 2 /air fuel cell. This performance is 20% higher as compared to the commercial available Pt/C catalyst. Fuel cell life test at a constant current density of 1000 mA cm -2 in a H 2 /O 2 condition shows good stability of anode Ir-V/C after 100 h of continuous operation.

  18. 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.)

  19. Surface/structure functionalization of copper-based catalysts by metal-support and/or metal–metal interactions

    Energy Technology Data Exchange (ETDEWEB)

    Konsolakis, Michalis, E-mail: mkonsol@science.tuc.gr [School of Production Engineering and Management, Technical University of Crete, GR-73100 Chania, Crete (Greece); Ioakeimidis, Zisis [Department of Mechanical Engineering, University of Western Macedonia, Bakola and Sialvera, GR-50100 Kozani (Greece)

    2014-11-30

    Highlights: • The surface chemistry of Cu-based catalysts is adjusted by metal-support or metal–metal interactions. • Three series of catalysts, i.e., Cu/REOs, Cu/Ce{sub 1−x}Sm{sub x}O{sub δ} and Cu–Co/CeO{sub 2} were prepared. • The local structure of Cu sites is remarkably affected by support or active phase modification. • Useful insights toward the fundamental understanding of Cu-catalyzed reactions are provided. - Abstract: Cu-based catalysts have recently attracted great attention both in catalysis and electro-catalysis fields due to their excellent catalytic performance and low cost. Given that their performance is determined, to a great extent, by Cu sites local environment, considerable efforts have been devoted on the strategic modifications of the electronic and structural properties of Cu sites. In this regard, the feasibility of tuning the local structure of Cu entities by means of metal-support or metal–metal interactions is investigated. More specifically, the physicochemical properties of Cu entities are modified by employing: (i) different oxides (CeO{sub 2}, La{sub 2}O{sub 3}, Sm{sub 2}O{sub 3}), or (ii) ceria-based mixed oxides (Ce{sub 1−x}Sm{sub x}O{sub δ}) as supporting carriers, and (iii) a second metal (Cobalt) adjacent to Cu (bimetallic Cu–Co/CeO{sub 2}). A characterization study, involving BET, XRD, TPR, and XPS, reveal that significant modifications on structural, redox and electronic properties of Cu sites can be induced by adopting either different oxide carriers or bimetallic complexes. Fundamental insights into the tuning of Cu local environment by metal-support or metal–metal interactions are provided, paving the way for real-life industrial applications.

  20. Spectroscopic evidence for origins of size and support effects on selectivity of Cu nanoparticle dehydrogenation catalysts.

    Science.gov (United States)

    Witzke, M E; Dietrich, P J; Ibrahim, M Y S; Al-Bardan, K; Triezenberg, M D; Flaherty, D W

    2017-01-03

    Selective dehydrogenation catalysts that produce acetaldehyde from bio-derived ethanol can increase the efficiency of subsequent processes such as C-C coupling over metal oxides to produce 1-butanol or 1,3-butadiene or oxidation to acetic acid. Here, we use in situ X-ray absorption spectroscopy and steady state kinetics experiments to identify Cu δ+ at the perimeter of supported Cu clusters as the active site for esterification and Cu 0 surface sites as sites for dehydrogenation. Correlation of dehydrogenation and esterification selectivities to in situ measures of Cu oxidation states show that this relationship holds for Cu clusters over a wide-range of diameters (2-35 nm) and catalyst supports and reveals that dehydrogenation selectivities may be controlled by manipulating either.

  1. Session 4: Combinatorial research of methane catalytic decomposition on supported nitride catalysts for CO-free hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Jianghan, Shen; Hua, Wang; Zhongmin, Liu; Hongchao, Liu [Natural Gas Utilization and Applied Catalysis Lab., Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian P. R. (China)

    2004-07-01

    CO-free Hydrogen production is needed for proton exchange membrane fuel cells (PEMs) because CO strongly poisons the anode-electrocatalysts. Methane directly catalytic decomposition is an attractive way to produce CO-free hydrogen for the large abundance of methane and its high H/C ratio. It is more effective to employ high-throughput screening (HTS) technology in heterogeneous catalysis. In this paper, a combinatorial multi-stream reaction system with online multi-stream mass spectrometer screening (MSMSS) detection technique was applied to study the decomposition of methane over supported MoN{sub x}O{sub y} catalysts (supports = Al{sub 2}O{sub 3}, SiO{sub 2}, SBA-15, ZSM-5,13X, and NaY), which is a catalyst system seldom reported recently. (authors)

  2. 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

  3. Alternative alkali resistant deNOx catalysts

    DEFF Research Database (Denmark)

    Putluru, Siva Sankar Reddy; Kristensen, Steffen Buus; Due-Hansen, Johannes

    2012-01-01

    by onepot sol–gel method. All catalysts were characterized by BET, XRPD and NH3-TPD. Initial SCR activities of 8 out of 9 catalysts showed higher NO conversion at least at one temperature in the temperature range 300–500 ◦C compared to the conventional V2O5-WO3/TiO2 catalyst. After potassium poisoning (100......Alternative alkali resistant deNOx catalysts were prepared using three different supports ZrO2, TiO2 and Mordenite zeolite. The majority of the catalysts were prepared by incipient wetness impregnation of a commercial support, with vanadium, copper or iron precursor, one catalyst was prepared......–130 µmol of K/g of catalyst) the relative drop in SCR activity and acidity was lower for all the alternative catalysts compared to the industrial V2O5-WO3/TiO2 catalyst. Furthermore, Cu/MOR and Nano-V2O5/Sul-TiO2 catalysts showed 8–16 times higher SCR activities than the conventional even after high...

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

    International Nuclear Information System (INIS)

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

    2013-01-01

    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 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 4 and H 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

  5. 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.

  6. Sea urchin-like mesoporous carbon material grown with carbon nanotubes as a cathode catalyst support for fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Kuo, Ping-Lin; Hsu, Chun-Han; Li, Wan-Ting; Jhan, Jing-Yi; Chen, Wei-Fu [Department of Chemical Engineering, National Cheng Kung University, Tainan 70101 (China)

    2010-12-15

    A sea urchin-like carbon (UC) material with high surface area (416 m{sup 2} g{sup -1}), adequate electrical conductivity (59.6 S cm{sup -1}) and good chemical stability was prepared by growing carbon nanotubes onto mesoporous carbon hollow spheres. A uniform dispersion of Pt nanoparticles was then anchored on the UC, where the Pt nanoparticles were prepared using benzylamine as the stabilizer. For this Pt loaded carbon, cyclic voltammogram measurements showed an exceptionally high electrochemically active surface area (EAS) (114.8 m{sup 2} g{sup -1}) compared to the commonly used commercial E-TEK catalyst (65.2 m{sup 2} g{sup -1}). The durability test demonstrates that the carbon used as a support exhibited minor loss in EAS of Pt. Compared to the E-TEK (20 wt%) cathode catalyst, this Pt loaded UC catalyst has greatly enhanced catalytic activity toward the oxygen reduction reaction, less cathode flooding and considerably improved performance, resulting in an enhancement of ca. 37% in power density compared with that of E-TEK. Based on the results obtained, the UC is an excellent support for Pt nanoparticles used as cathode catalysts in proton exchange membrane fuel cells. (author)

  7. Methanol Oxidation Using Ozone on Titania-Supported Vanadium Catalyst

    Science.gov (United States)

    Ozone-enhanced catalytic oxidation of methanol has been conducted at mild temperatures of 100 to 250NC using V2O5/TiO2 catalyst prepared by the sol-gel method. The catalyst was characterized using XRD, surface area measurements, and temperature-programmed desorption of methanol. ...

  8. Metal-Organic-Framework mediated supported-cobalt catalysts in multiphase hydrogenation reactions

    OpenAIRE

    Sun, X.

    2017-01-01

    The production of most industrially important chemicals involves catalysis. Depending on the difference in phases between the catalysts and reactants, one distinguishes homogenous catalysis and heterogeneous catalysis, with the latter being more attractive in real applications, due to the easy separation of products from catalysts and reusing the latter. In spite of the research and development of heterogeneous catalysts for decades, the exploration for catalysts system with outstanding activ...

  9. Hydrotreating and hydrocracking of Athabasca bitumen derived heavy gas oils using NiMo catalyst supported on titania modified alumina

    Energy Technology Data Exchange (ETDEWEB)

    Ferdous, D.; Bakhshi, N.N.; Dalai, A.K.; Adjaye, J. [Saskatchewan Univ., Saskatoon, SK (Canada). Dept. of Chemical Engineering, Catalysis and Chemical Reaction Engineering Laboratories]|[Syncrude Canada Ltd., Edmonton, AB (Canada)

    2006-07-01

    Different NiMo catalysts supported on titania modified Al{sub 2}O{sub 3} were synthesized and characterized in an effort to study the hydrodenitrigenation (HDN) and hydrodesulfurization (HDS) of different gas oils derived from Athabasca bitumen. The Al{sub x}O{sub 3} supports were modified by incorporating up to 9 wt per cent titanium (Ti). All modified supports as well as fresh and spent catalysts were characterized by BET surface area, pore volume and pore diameter, XRD, TPR, TPD and SEM. A trickle-bed reactor using 3 different gas oils from the Athabasca bitumen was used to test the initial activity of these catalysts. The 3 oils were light gas oil (LGO), heavy gas oil (HGO) and blended gas oil having 50 per cent LGO and 50 per cent HGO. The study showed that nitrogen conversion increased for all the gas oils when Ti was incorporated into the alumina. With an increase in Ti concentrations from 0 to 6 wt per cent, nitrogen conversion increased from 57-69.5 wt per cent, 75-80.2 wt per cent, 83-91.5 wt per cent and for LGO, HGO and blended, respectively. Nearly 86 wt per cent sulphur conversion was obtained for all Ti concentrations for LGO, while HGO and blended sulphur conversions were in the range of 96-97 wt per cent. Detailed hydrotreating and hydrocracking of HGO was then performed using the 6 wt per cent Ti modified catalyst because it achieved the maximum nitrogen conversion. This paper also presented the temperature, pressure and liquid hourly space velocity for this catalyst along with the maximum nitrogen and sulphur conversions. Results were compared with those of commercial catalysts. tabs., figs.

  10. Low-Temperature Oxidation of Dimethyl Ether to Polyoxymethylene Dimethyl Ethers over CNT-Supported Rhenium Catalyst

    Directory of Open Access Journals (Sweden)

    Qingde Zhang

    2016-03-01

    Full Text Available Due to its excellent conductivity, good thermal stability and large specific surface area, carbon nano-tubes (CNTs were selected as support to prepare a Re-based catalyst for dimethyl ether (DME direct oxidation to polyoxymethylene dimethyl ethers (DMMx. The catalyst performance was tested in a continuous flow type fixed-bed reactor. H3PW12O40 (PW12 was used to modify Re/CNTs to improve its activity and selectivity. The effects of PW12 content, reaction temperature, gas hourly space velocity (GHSV and reaction time on DME oxidation to DMMx were investigated. The results showed that modification of CNT-supported Re with 30% PW12 significantly increased the selectivity of DMM and DMM2 up to 59.0% from 6.6% with a DME conversion of 8.9%; besides that, there was no COx production observed in the reaction under the optimum conditions of 513 K and 1800 h−1. The techniques of XRD, BET, NH3-TPD, H2-TPR, XPS, TEM and SEM were used to characterize the structure, surface properties and morphology of the catalysts. The optimum amount of weak acid sites and redox sites promotes the synthesis of DMM and DMM2 from DME direct oxidation.

  11. Autothermal reforming catalyst having perovskite structure

    Science.gov (United States)

    Krumpel, Michael [Naperville, IL; Liu, Di-Jia [Naperville, IL

    2009-03-24

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

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

    KAUST Repository

    Atiqullah, Muhammad; Cibulková , Zuzana; Černá , Andrea; Šimon, Peter; Hussain, Ikram; Al-Harthi, Mamdouh A.; Anantawaraskul, Siripon

    2014-01-01

    © 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

  13. Hydrodeoxygenation of phenols as lignin models under acid-free conditions with carbon-supported platinum catalysts.

    Science.gov (United States)

    Ohta, Hidetoshi; Kobayashi, Hirokazu; Hara, Kenji; Fukuoka, Atsushi

    2011-11-28

    Carbon-supported Pt catalysts are highly active and reusable for the aqueous-phase hydrodeoxygenation of phenols as lignin models without adding any acids. It is suggested that Pt/carbon facilitates the hydrogenation of phenols and the hydrogenolysis of the resulting cyclohexanols.

  14. Nanoparticle-Supported Molecular Polymerization Catalysts

    OpenAIRE

    Amgoune, Abderramane; Krumova, Marina; Mecking, Stefan

    2008-01-01

    Homogeneous molecular catalysts are immobilzed in a well-defined fashion on individual silica nanoparticles with a narrow particle size distribution by covalent attachment. This synthetic methodology is demonstrated with modified salicylaldiminato-substituted titanium(IV) complexes incorporating a trimethoxysilane-terminated linker: dichloro-bis[κ2-N,O-6-(3-(trimethoxysilyl)propoxyphenylimino)-2-tert-butyl-phenolato]titanium(IV) (3) and dichlorobis[κ2-N,O-6-(4-(trimethoxysilyl)propoxy-2,3,5,6...

  15. Mesoporous silica nanoparticle supported PdIr bimetal catalyst for selective hydrogenation, and the significant promotional effect of Ir

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Hui; Huang, Chao; Yang, Fan [The Key Laboratory of Fuel Cell Technology of Guangdong Province, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510641 (China); Yang, Xu [Key Laboratory of Renewable Energy, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou (China); Du, Li [The Key Laboratory of Fuel Cell Technology of Guangdong Province, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510641 (China); Key Laboratory of Renewable Energy, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou (China); Liao, Shijun, E-mail: chsjliao@scut.edu.cn [The Key Laboratory of Fuel Cell Technology of Guangdong Province, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510641 (China); Key Laboratory of Renewable Energy, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou (China)

    2015-12-01

    Graphical abstract: A mesoporous silica nanoparticle (MSN) supported bimetal catalyst, PdIr/MSN, was prepared by a facile impregnation and hydrogen reduction method. The strong promotional effect of Ir was observed and thoroughly investigated. At the optimal molar ratio of Ir to Pd (N{sub Ir}/N{sub Pd} = 0.1), the activity of PdIr{sub 0.1}/MSN was up to eight times and 28 times higher than that of monometallic Pd/MSN and Ir/MSN, respectively. The catalysts were characterized comprehensively by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, and hydrogen temperature programmed reduction, which revealed that the promotional effect of Ir may be due to the enhanced dispersion of active components on the MSN, and to the intensified Pd–Ir electronic interaction caused by the addition of Ir. - Highlights: • Mesoporous nanoparticles were synthesized and used as support for metal catalyst. • PdIr bimetallic catalyst exhibited significantly improved hydrogenation activity. • The strong promotion of Ir was recognized firstly and investigated intensively. • PdIr exhibits 18 times higher activity than Pd to the hydrogenation of nitrobenzene. - Abstract: A mesoporous silica nanoparticle (MSN) supported bimetal catalyst, PdIr/MSN, was prepared by a facile impregnation and hydrogen reduction method. The strong promotional effect of Ir was observed and thoroughly investigated. At the optimal molar ratio of Ir to Pd (N{sub Ir}/N{sub Pd} = 0.1), the activity of PdIr{sub 0.1}/MSN was up to eight times and 28 times higher than that of monometallic Pd/MSN and Ir/MSN, respectively. The catalysts were characterized comprehensively by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, and hydrogen temperature programmed reduction, which revealed that the promotional effect of Ir may be due to the enhanced dispersion of active components on the MSN, and to the intensified Pd–Ir electronic interaction

  16. Two Catalysts for Selective Oxidation of Contaminant Gases

    Science.gov (United States)

    Wright, John D.

    2011-01-01

    Two catalysts for the selective oxidation of trace amounts of contaminant gases in air have been developed for use aboard the International Space Station. These catalysts might also be useful for reducing concentrations of fumes in terrestrial industrial facilities especially facilities that use halocarbons as solvents, refrigerant liquids, and foaming agents, as well as facilities that generate or utilize ammonia. The first catalyst is of the supported-precious-metal type. This catalyst is highly active for the oxidation of halocarbons, hydrocarbons, and oxygenates at low concentrations in air. This catalyst is more active for the oxidation of hydrocarbons and halocarbons than are competing catalysts developed in recent years. This catalyst completely converts these airborne contaminant gases to carbon dioxide, water, and mineral acids that can be easily removed from the air, and does not make any chlorine gas in the process. The catalyst is thermally stable and is not poisoned by chlorine or fluorine atoms produced on its surface during the destruction of a halocarbon. In addition, the catalyst can selectively oxidize ammonia to nitrogen at a temperature between 200 and 260 C, without making nitrogen oxides, which are toxic. The temperature of 260 C is higher than the operational temperature of any other precious-metal catalyst that can selectively oxidize ammonia. The purpose of the platinum in this catalyst is to oxidize hydrocarbons and to ensure that the oxidation of halocarbons goes to completion. However, the platinum exhibits little or no activity for initiating the destruction of halocarbons. Instead, the attack on the halocarbons is initiated by the support. The support also provides a high surface area for exposure of the platinum. Moreover, the support resists deactivation or destruction by halogens released during the destruction of halocarbons. The second catalyst is of the supported- metal-oxide type. This catalyst can selectively oxidize ammonia to

  17. A Study of CO2 Methanation over Ni-Based Catalysts Supported by CNTs with Various Textural Characteristics

    OpenAIRE

    Yanyan Feng; Wen Yang; Wei Chu

    2015-01-01

    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 indica...

  18. Flower-Like ZnO-Assisted One-Pot Encapsulation of Noble Metal Nanoparticles Supported Catalysts with ZIFs

    Science.gov (United States)

    Lin, Lu; Liu, Haiou; Zhang, Xiongfu

    2018-03-01

    Rational design of efficient approaches to fabricate MOFs-coated core-shell composites is promising but challenging. We report here the encapsulation of Pd nanoparticles (Pd NPs) supported flower-like ZnO (F-ZnO) microspheres with ZIF-8 shell through a facile strategy, in which the formation and immobilization of Pd NPs on F-ZnO supports and the subsequent growth of ZIF-8 shells over them are effectively integrated into one-pot synthetic route. Importantly, the utilization of ZnO both as support of Pd NPs and Zn2+ source of ZIF-8 is favorable for the implement of one-pot synthesis, due to its functions in anchoring Pd NPs and inducing ZIF-8 formation. Further insights into the morphological influence of zinc oxide particles on the resulting materials indicate that the flower-like microspheres with 2D nanosheets as subunits also benefit the coating of Pd NPs supported cores with ZIF-8, resulting in a well-defined core-shell catalyst. The achieved catalyst deliveries remarkable performance in terms of selectivity, anti-poisoning and recyclability in the liquid hydrogenations of alkenes.

  19. Tungsten carbide/porous carbon composite as superior support for platinum catalyst toward methanol electro-oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Liming [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); Fu, Honggang, E-mail: fuhg@vip.sina.com [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); Key Laboratory of Functional Inorganic Material Chemistry, Heilongjiang University, Harbin 150080 (China); Wang, Lei; Mu, Guang; Jiang, Baojiang; Zhou, Wei; Wang, Ruihong [Key Laboratory of Functional Inorganic Material Chemistry, Heilongjiang University, Harbin 150080 (China)

    2014-01-01

    Graphical abstract: The WC nanoparticles are well dispersed in the carbon matrix. The size of WC nanoparticles is about 30 nm. It can be concluded that tungsten carbide and carbon composite was successfully prepared by the present synthesis conditions. - Highlights: • The WC/PC composite with high specific surface area was prepared by a simple way. • The Pt/WC/PC catalyst has superior performance toward methanol electro-oxidation. • The current density for methanol electro-oxidation is as high as 595.93 A g{sup −1} Pt. • The Pt/WC/PC catalyst shows better durability and stronger CO electro-oxidation. • The performance of Pt/WC/PC is superior to the commercial Pt/C (JM) catalyst. - Abstract: Tungsten carbide/porous carbon (WC/PC) composites have been successfully synthesized through a surfactant assisted evaporation-induced-assembly method, followed by a thermal treatment process. In particular, WC/PC-35-1000 composite with tungsten content of 35% synthesized at the carbonized temperature of 1000 °C, exhibited a specific surface area (S{sub BET}) of 457.92 m{sup 2} g{sup −1}. After loading Pt nanoparticles (NPs), the obtained Pt/WC/PC-35-1000 catalyst exhibits the highest unit mass electroactivity (595.93 A g{sup −1} Pt) toward methanol electro-oxidation, which is about 2.6 times as that of the commercial Pt/C (JM) catalyst. Furthermore, the Pt/WC/PC-35-1000 catalyst displays much stronger resistance to CO poisoning and better durability toward methanol electrooxidation compared with the commercial Pt/C (JM) catalyst. The high electrocatalytic activity, strong poison-resistivity and good stability of Pt/WC/PC-35-1000 catalyst are attributed to the porous structures and high specific surface area of WC/PC support could facilitate the rapid mass transportation. Moreover, synergistic effect between WC and Pt NPs is favorable to the higher catalytic performance.

  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...... different surface areas (ranging from 20 to 235 m2 g-1) in this reaction. The activity for CO methanation, under steady-state conditions, was found to strongly depend on the TiO2 support surface area, increasing first with increasing surface area up to a maximum activity for the Ru/TiO2 catalyst...... 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...

  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. Catalyst containing oxygen transport membrane

    Science.gov (United States)

    Christie, Gervase Maxwell; Wilson, Jamie Robyn; van Hassel, Bart Antonie

    2012-12-04

    A composite oxygen transport membrane having a dense layer, a porous support layer and an intermediate porous layer located between the dense layer and the porous support layer. Both the dense layer and the intermediate porous layer are formed from an ionic conductive material to conduct oxygen ions and an electrically conductive material to conduct electrons. The porous support layer has a high permeability, high porosity, and a high average pore diameter and the intermediate porous layer has a lower permeability and lower pore diameter than the porous support layer. Catalyst particles selected to promote oxidation of a combustible substance are located in the intermediate porous layer and in the porous support adjacent to the intermediate porous layer. The catalyst particles can be formed by wicking a solution of catalyst precursors through the porous support toward the intermediate porous layer.

  3. Antimony Doped Tin Oxides and Their Composites with Tin pyrophosphates as Catalyst Supports for Oxygen Evolution Reaction in Proton Exchange Membrane Water Electrolysis

    DEFF Research Database (Denmark)

    Xu, Junyuan; Li, Qingfeng; Christensen, Erik

    2012-01-01

    Proton exchange membrane water electrolysers operating at typically 80 °C or at further elevated temperatures suffer from insufficient catalyst activity and durability. In this work, antimony doped tin oxide nanoparticles were synthesized and further doped with an inorganic proton conducting phase...... based on tin pyrophosphates as the catalyst support. The materials showed an overall conductivity of 0.57 S cm−1 at 130 °C under the water vapor atmosphere with a contribution of the proton conduction. Using this composite support, iridium oxide nanoparticle catalysts were prepared and characterized...

  4. Preventing maritime transport of pathogens: the remarkable antimicrobial properties of silver-supported catalysts for ship ballast water disinfection.

    Science.gov (United States)

    Theologides, C P; Theofilou, S P; Anayiotos, A; Costa, C N

    2017-07-01

    Ship ballast water (SBW) antimicrobial treatment is considered as a priority issue for the shipping industry. The present work investigates the possibility of utilizing antimicrobial catalysis as an effective method for the treatment of SBW. Taking into account the well-known antimicrobial properties of ionic silver (Ag + ), five silver-supported catalysts (Ag/γ-Al 2 O 3 ) with various loadings (0.05, 0.1, 0.2, 0.5, and 1 wt%) were prepared and examined for the antimicrobial treatment of SBW. The bactericidal activity of the aforementioned catalysts was investigated towards the inhibition of Escherichia coli (Gram-negative) and Escherichia faecalis (Gram-positive) bacteria. Catalytic experiments were conducted in a three-phase continuous flow stirred tank reactor, used in a semi-batch mode. It was found that using the catalyst with the lowest metal loading, the inhibition of E. coli reached 95.8% after 30 minutes of treatment of an E. coli bacterial solution, while the inhibition obtained for E. faecalis was 76.2% after 60 minutes of treatment of an E. faecalis bacterial solution. Even better results (100% inhibition after 5 min of reaction) were obtained using the catalysts with higher Ag loadings. The results of the present work indicate that the prepared monometallic catalysts exert their antimicrobial activity within a short period of time, revealing, for the first time ever, that the field of antimicrobial heterogeneous catalysis using deposited ionic silver on a solid support may prove decisive for the disinfection of SBW.

  5. Silica Supported Platinum Catalysts for Total Oxidation of the Polyaromatic Hydrocarbon Naphthalene: An Investigation of Metal Loading and Calcination Temperature

    Directory of Open Access Journals (Sweden)

    David R. Sellick

    2015-04-01

    Full Text Available A range of catalysts comprising of platinum supported on silica, prepared by an impregnation method, have been studied for the total oxidation of naphthalene, which is a representative Polycyclic Aromatic Hydrocarbon. The influence of platinum loading and calcination temperature on oxidation activity was evaluated. Increasing the platinum loading up to 2.5 wt.% increased the catalyst activity, whilst a 5.0 wt.% catalyst was slightly less active. The catalyst containing the optimum 2.5 wt.% loading was most active after calcination in air at 550 °C. Characterisation by carbon monoxide chemisorption and X-ray photoelectron spectroscopy showed that low platinum dispersion to form large platinum particles, in combination with platinum in metallic and oxidised states was important for high catalyst activity. Catalyst performance improved after initial use in repeat cycles, whilst there was slight deactivation after prolonged time-on-stream.

  6. 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.)

  7. Selective hydrogenation of halogenated arenes using porous manganese oxide (OMS-2) and platinum supported OMS-2 catalysts.

    Science.gov (United States)

    McManus, Iain J; Daly, Helen; Manyar, Haresh G; Taylor, S F Rebecca; Thompson, Jillian M; Hardacre, Christopher

    2016-07-04

    Porous manganese oxide (OMS-2) and platinum supported on OMS-2 catalysts have been shown to facilitate the hydrogenation of the nitro group in chloronitrobenzene to give chloroaniline with no dehalogenation. Complete conversion was obtained within 2 h at 25 °C and, although the rate of reaction increased with increasing temperature up to 100 °C, the selectivity to chloroaniline remained at 99.0%. Use of Pd/OMS-2 or Pt/Al2O3 resulted in significant dechlorination even at 25 °C and 2 bar hydrogen pressure giving a selectivity to chloroaniline of 34.5% and 77.8%, respectively, at complete conversion. This demonstrates the potential of using platinum group metal free catalysts for the selective hydrogenation of halogenated aromatics. Two pathways were observed for the analogous nitrobenzene hydrogenation depending on the catalyst used. The hydrogenation of nitrobenzene was found to follow a direct pathway to aniline and nitrosobenzene over Pd/OMS-2 in contrast to the OMS and Pt/OMS-2 catalysts which resulted in formation of nitrosobenzene, azoxybenzene and azobenzene/hydrazobenzene intermediates before complete conversion to aniline. These results indicate that for Pt/OMS-2 the hydrogenation proceeds predominantly over the support with the metal acting to dissociate hydrogen. In the case of Pd/OMS-2 both the hydrogenation and hydrogen adsorption occur on the metal sites.

  8. Supported zirconium sulfate on carbon nanotubes as water-tolerant solid acid catalyst

    International Nuclear Information System (INIS)

    Juan, Joon Ching; Jiang Yajie; Meng Xiujuan; Cao Weiliang; Yarmo, Mohd Ambar; Zhang Jingchang

    2007-01-01

    A new solid acid of zirconium sulfate (CZ) was successfully supported on carbon nanotube (CNT) for esterification reaction. Preparation conditions of the supported CZ have been investigated, to obtain highest catalytic activity for esterification reaction. XRD, TEM, BET, X-ray photoelectron spectra (XPS) and in situ FTIR analysis has also been carried out to understand the characteristics of the catalyst. In the esterification of acrylic acid with n-octanol, the supported CZ exhibited high catalytic activity and stability. The catalytic activity was nearly unchanged during four times of reuse. XRD and TEM analysis indicated that CZ was finely dispersed on CNT. XPS analysis shows that the CZ species was preserved and the chemical environment of the CZ has changed after loaded on CNT. This finding show that CNT as CZ support is an efficient water-tolerant solid acid

  9. Light alkane (mixed feed selective dehydrogenation using bi-metallic zeolite supported catalyst

    Directory of Open Access Journals (Sweden)

    Zeeshan Nawaz

    2009-12-01

    Full Text Available Light alkanes are the important intermediates of many refinery processes and their catalytic dehydrogenation gives corresponding alkenes. The aim behind this experimentation is to investigate reaction behavior of mixed alkanes during direct catalytic dehydrogenation and emphasis has been given to enhance propene. Bi-metallic zeolite supported catalyst Pt-Sn/ZSM-5 was prepared by sequentional impregnation method and characterized by BET, EDS and XRD. Direct dehydrogenation reaction is highly endothermic and its conversion is thermodynamically limited. Results showed that the increase in temperature increases the conversion to some extent but there is no overall effect on selectivity of propene. Increase in time-on-stream (TOS remarkably improves propene selectivity at the expense of lower conversion. The performances of bi-metallic zeolite based catalyst largely affected by coke deposition. The presence of butane and ethane adversely affected propane conversion. Optimum propene selectivity is about 48 %, obtained at 600 oC and time-on-stream 10 h.

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

    DEFF Research Database (Denmark)

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

    2017-01-01

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

  11. In Situ Raman Spectroscopy of Supported Chromium Oxide Catalysts: Reactivity Studies with Methanol and Butane

    NARCIS (Netherlands)

    Weckhuysen, B.M.; Wachs, I.E.

    1996-01-01

    The interactions of methanol and butane with supported chromium oxide catalysts under oxidizing and reducing conditions were studied by in situ Raman spectroscopy as a function of the specific oxide support (Al2O3, ZrO2, TiO2, SiO2, Nb2O5, 3% SiO2/TiO2, 3% TiO2/SiO2, and a physical mixture of SiO2

  12. Preparation, characterization of Mo catalysts supported on Ni- containing calcium deficient hydroxyapatite and reactivity for the thiophene HDS reaction

    Directory of Open Access Journals (Sweden)

    Cherif A.

    2013-09-01

    Full Text Available Ni-containing Calcium Hydroxyapatite (NiCaHAp; 3.31 wt.% Ni was synthesized by coprecipitation and used as catalyst support. Molybdenum was supported on NiCaHAp by impregnation using ammonium heptamolybdate. The prepared catalysts Mo(x/NiCaHAp (x: 2 to 8 wt % in Mo were characterized by elemental analysis, XRD, FT-IR, N2 adsorption-desorption and TEM-EDX. The catalysts were sulfided in-situ at 673 K under flowing H2S/H2 (15 Vol.% H2S and tested in hydrodesulfurization (HDS of thiophene at 673 K. The main XRD peaks of hydroxyapatite CaHAp phase were observed in all samples and a peak due probably to crystalline MoO3 phase was also identified from the results. However, no crystalline phase of NiO was found for the catalysts, which showed its Ni species were highly dispersed. The sulfided catalysts Mo(x/NiCaHAp presented are active in HDS of thiophene, despite the presence of some large MoO3 crystallites and incomplete sulfidation. This activity may be due to interaction of NiO and MoO3 on CaHAp resulting in the formation of Ni-Mo-S phase under flowing H2S/H2. When the molybdenum content increased the HDS activity increasead slightly, which was caused by the agglomeration of MoO3. The Mo(8/NiCaHAp catalyst is about two times less active for thiophene HDS than the commercial NiMoP/Al2O3.

  13. A Comparative Study of Mn/Co Binary Metal Catalysts Supported on Two Commercial Diatomaceous Earths for Oxidation of Benzene

    Directory of Open Access Journals (Sweden)

    Marco Tomatis

    2018-03-01

    Full Text Available Two commercial diatomaceous earths were used as supports for the preparation of Mn/Co binary metal catalysts at different metal loads (5 to 10 wt % Mn and 5 to 15 wt % Co by incipient wetness deposition. The activity of the prepared catalysts towards the complete oxidation of benzene to CO2 and water was investigated between 100 and 400 °C. Raw supports and synthesized catalysts were characterized by XRD, N2 physisorption, SEM-EDS, H2-TPR, and TPD. The purification treatment of food-grade diatomite significantly affected the crystallinity of this support while reducing its specific surface area (SSA. A loss of SSA, associated with the increase in the metal load, was observed on samples prepared on natural diatomite, while the opposite trend occurred with food-grade diatomite-supported catalysts. Metal nanoparticles of around 50 nm diameter were observed on the catalysts’ surface by SEM analysis. EDS analysis confirmed the uniform deposition of the active phases on the support’s surface. A larger H2 consumption was found by TPR analysis of natural diatomite-based samples in comparison to those prepared at the same metal load on food-grade diatomite. During the catalytic oxidation experiment, over 90% conversion of benzene were achieved at a reaction temperature of 225 °C by all of the prepared samples. In addition, the formation of coke during the oxidation tests was demonstrated by TGA analysis and the soluble fraction of the produced coke was characterized by GC-MS.

  14. Carbon nanotubes and other nanostructures as support material for nanoparticulate noble-metal catalysts in fuel cells

    DEFF Research Database (Denmark)

    Veltzé, Sune; Larsen, Mikkel Juul; Elina, Yli-Rantala

    or platinum-alloy catalysts in the electrodes are required. To maximize the utilization of the noble metal it is frequently deposited as nanoparticles (1–5 nm) on a stabilizing support of carbon black. Carbon black provides good anchoring of the catalyst particles, but is prone to severe destructive oxidation...... at high electrical potentials encountered occasionally in fuel cells. Other nanostructures of carbon are being investigated as alternatives to carbon black as they have several beneficial properties. Multi-walled carbon nanotubes (MW-CNT) are an example of one type of these promising materials. Like...... of the fuel-cell electrodes. However, the low concentration of structural defects also poses challenges with regard to anchoring of the catalyst particles on the CNT surface. Thus, activation treatments introducing surface functional groups may be necessary. Also, the surface properties are responsible...

  15. Effect of K promoter on the structure and catalytic behavior of supported iron-based catalysts in fischer-tropsch synthesis

    Directory of Open Access Journals (Sweden)

    F. E. M Farias

    2011-09-01

    Full Text Available Effects of K addition on the performance of supported Fe catalysts for Fischer - Tropsch synthesis (FTS were studied in a slurry reactor at 240 to 270ºC, 2.0 to 4.0 MPa and syngas H2/CO = 1.0. The catalysts were characterized by N2 adsorption, H2 temperature programmed reduction, X - ray diffraction, X - ray fluorescence, thermogravimetric analysis, scanning electron microscopy and dispersive X - ray spectroscopy. A strong interaction was observed between Fe and K, which inhibited the reduction of Fe catalyst. Addition of potassium increased the production of heavy hydrocarbons (C20+.

  16. Fischer-Tropsch Performance of an SiO2-Supported Co-Based Catalyst Prepared by Hydrogen Dielectric-Barrier Discharge Plasma

    International Nuclear Information System (INIS)

    Fu Tingjun; Huang Chengdu; Lv Jing; Li Zhenhua

    2014-01-01

    A silica-supported cobalt catalyst was prepared by hydrogen dielectric-barrier discharge (H 2 -DBD) plasma. Compared to thermal hydrogen reduction, H 2 -DBD plasma treatment can not only fully decompose the cobalt precursor but also partially reduce the cobalt oxides at lower temperature and with less time. The effect of the discharge atmosphere on the property of the plasma-prepared catalyst and the Fischer-Tropsch synthesis activity was studied. The results indicate that H 2 -DBD plasma treatment is a promising alternative for preparing Co/SiO 2 catalysts from the viewpoint of energy savings and efficiency

  17. 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....

  18. Formaldehyde formation in coupled oxidation of methane and methanol over V2O5 and MoO3 silica supported catalysts

    International Nuclear Information System (INIS)

    Lojewska, J.; Makowski, W.; Fajardo Farre, A.; Dziembaj, R.

    2003-01-01

    The effect of methanol on partial oxidation of methane has been studied on standard molybdena and vanadia catalysts supported on silica. Prior to catalytic tests the catalysts were characterized by BET, SEM/EDAX and TPR/O methods. Three types of catalytic tests were performed giving temperature and contact time dependence on the catalyst activity and selectivity: partial oxidations of methane, methanol and methane/methanol mixtures. The methanol showed an activating impact on the partial oxidation of methane over all used catalysts samples, but the strongest one over Mo 3 /SiO 2 . In the absence of CH 3 OH the only catalyst, which exhibited HCHO selectivity, was low loaded vanadia catalyst. It has been put forward that methanol may enhance formation of oxygen active species, prerequisites for activating methane molecules, through reducing vanadia cations and causing breakage of vanadium oxygen bonds. (author)

  19. Hydrogenation of toluene on Ni-Co-Mo supported zeolite catalysts ...

    African Journals Online (AJOL)

    -a, HY-b and Mordenite were prepared and characterized using many techniques for use as hydrotreating catalysts. In a preliminary investigation, toluene was employed as model compound to test the catalysts in hydrogenation, as a major ...

  20. Modified fly ash from municipal solid waste incineration as catalyst support for Mn-Ce composite oxides

    Science.gov (United States)

    Chen, Xiongbo; Liu, Ying; Yang, Ying; Ren, Tingyan; Pan, Lang; Fang, Ping; Chen, Dingsheng; Cen, Chaoping

    2017-08-01

    Fly ash from municipal solid waste incineration was modified by hydrothermal treatment and used as catalyst support for Mn-Ce composite oxides. The prepared catalyst showed good activity for the selective catalytic reduction (SCR) of NO by NH3. A NO conversion of 93% could be achieved at 300 °C under a GHSV of 32857 h-1. With the help of characterizations including XRD, BET, SEM, TEM, XPS and TPR, it was found that hydrothermal treatment brought a large surface area and abundant mesoporous to the modified fly ash, and Mn-Ce composite oxides were highly dispersed on the surface of the support. These physical and chemical properties were the intrinsic reasons for the good SCR activity. This work transformed fly ash into high value-added products, providing a new approach to the resource utilization and pollution control of fly ash.

  1. Extended X-ray absorption fine structure and X-ray diffraction studies on supported Ni catalysts

    International Nuclear Information System (INIS)

    Aldea, N.; Marginean, P.; Yaning, Xie; Tiandou, Hu; Tao, Liu; Wu, Zhongua; ZhenYa, Dai

    1999-01-01

    In the first part of this paper, we present a study based on EXAFS spectroscopy. This method can yield structural information about the local environment around a specific atomic constituent in the amorphous materials, the location and chemical state of any catalytic atom on any support or point defect structures, in alloys and composites. EXAFS is a specific technique of the scattering of X-ray on materials. The present study is aimed toward elucidation of the local structure of Ni atoms and their interaction with oxide support. The second goal of the paper consists in X-ray diffraction on the same samples. X-ray diffraction method that is capable to determine average particle size, microstrains, probability of faults as well as particle size distribution function of supported Ni catalysts is presented. The method is based on the Fourier analysis of a single X-Ray diffraction profile. The results obtained on supported nickel catalysts, which are used in H/D isotopic exchange reactions are reported. The global structure is obtained with a new fitting method based on the Generalised Fermi Function facilities for approximation and Fourier transform of the experimental X-Ray line profiles. Both types of measurements were performed on Beijing Synchrotron Radiation Facilities (BSRF). (authors)

  2. Fischer-Tropsch synthesis: Support and cobalt cluster size effects on kinetics over Co/Al{sub 2}O{sub 3} and Co/SiO{sub 2} catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Wenping Ma; Gary Jacobs; Dennis E. Sparks; Muthu K. Gnanamani; Venkat Ramana Rao Pendyala; Chia H. Yen; Jennifer L.S. Klettlinger; Thomas M. Tomsik; Burtron H. Davis [University of Kentucky, Lexington, KY (USA). Center for Applied Energy Research

    2011-02-15

    The influence of support type and cobalt cluster size (i.e., with average diameters falling within the range of 8-40 nm) on the kinetics of Fischer-Tropsch synthesis (FT) were investigated by kinetic tests employing a CSTR and two Co/{gamma}-Al{sub 2}O{sub 3} catalysts having different average pore sizes, and two Co/SiO{sub 2} catalysts prepared on the same support but having different loadings. A kinetic model -r{sub CO}=kP{sup a}{sub co}P{sup b}{sub H2}/(1 + mP{sub H2O}/P{sub H2}) that contains a water effect constant 'm' was used to fit the experimental data obtained with all four catalysts. Kinetic parameters suggest that both support type and average Co particle size impact FT behavior. Cobalt cluster size influenced kinetic parameters such as reaction order, rate constant, and the water effect parameter.Decreasing the average Co cluster diameter by about 30% led to an increase in the intrinsic reaction rate constant k, defined on a per g of catalyst basis, by 62-102% for the {gamma}-Al{sub 2}O{sub 3} and SiO{sub 2}-supported cobalt catalysts. Moreover, less inhibition by adsorbed CO and greater H{sub 2} dissociation on catalysts having smaller Co particles was suggested by the higher a and lower b values obtained for the measured reaction orders. Irrespective of support type, the catalysts having smaller average Co particles were more sensitive to water. Comparing the catalysts having strong interactions between cobalt and support (Co/Al{sub 2}O{sub 3}) to the ones with weak interactions (Co/SiO{sub 2}), the water effect parameters were found to be positive (indicating a negative influence on CO conversion) and negative (denoting a positive effect on CO conversion), respectively. Greater a and a/b values were observed for both Al{sub 2}O{sub 3}-supported Co catalysts, implying greater inhibition of the FT rate by strongly adsorbed CO on Co/Al{sub 2}O{sub 3} relative to Co/SiO{sub 2}. 78 refs., 4 figs., 3 tabs.

  3. The structure and function of supported molybdenum nitride and molybdenum carbide hydrotreating catalysts

    Science.gov (United States)

    Dolce, Gregory Martin

    1997-11-01

    A series of gamma-Alsb2Osb3 supported molybdenum nitrides and carbides were prepared by the temperature programmed reaction of supported molybdates with ammonia and methane/hydrogen mixtures, respectively. In the first part of this research, the effects of synthesis heating rates and molybdenum loading on the catalytic properties of the materials were examined. A significant amount of excess carbon was deposited on the surface of the carbides during synthesis. The materials consisted of small particles which were very highly dispersed. Oxygen chemisorption indicated that the nitride particles may have been two-dimensional. The dispersion of the carbides, however, appeared to decrease as the loading increased. The catalysts were evaluated for hydrodenitrogenation (HDN), hydrodesulfurization (HDS), and hydrodeoxygenation (HDO). The molybdenum loading had the largest effect on the activity of the materials. For the nitrides, the HDN and HDS activities were inverse functions of the loading. This suggested that the most active HDN and HDS sites were located at the perimeter of the two-dimensional particles. The HDN and HDS activities of the carbides followed the same trend as the oxygen uptake. This result suggested that oxygen titrated the active sites on the supported carbides. Selected catalysts were evaluated for methylcarbazole HDN, dibenzothiophene HDS, and dibenzofuran HDO. The activity and selectivity of the nitrides and carbides were competitive with a presulfided commercial catalyst. In the second part of this work, a series of supported nitrides and carbides were prepared using a wider range of loadings (5-30 wt% Mo). Thermogravimetric analysis was used to determine the temperature at which excess carbon was deposited on the carbides. By modifying the synthesis parameters, the deposition of excess carbon was effectively inhibited. The dispersions of the supported nitrides and carbides were constant and suggested that the materials consisted of two

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

    NARCIS (Netherlands)

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

    2015-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-05-01

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

  6. Pt-Fe catalyst nanoparticles supported on single-wall carbon nanotubes: Direct synthesis and electrochemical performance for methanol oxidation

    Science.gov (United States)

    Ma, Xiaohui; Luo, Liqiang; Zhu, Limei; Yu, Liming; Sheng, Leimei; An, Kang; Ando, Yoshinori; Zhao, Xinluo

    2013-11-01

    Single-wall carbon nanotubes (SWCNTs) supported Pt-Fe nanoparticles have been prepared by one-step hydrogen arc discharge evaporation of carbon electrode containing both Pt and Fe metal elements. The formation of SWCNTs and Pt-Fe nanoparticles occur simultaneously during the evaporation process. High-temperature hydrogen treatment and hydrochloric acid soaking have been carried out to purify and activate those materials in order to obtain a new type of Pt-Fe/SWCNTs catalyst for methanol oxidation. The Pt-Fe/SWCNTs catalyst performs much higher electrocatalytic activity for methanol oxidation, better stability and better durability than a commercial Pt/C catalyst according to the electrochemical measurements, indicating that it has a great potential for applications in direct methanol fuel cells.

  7. The black rock series supported SCR catalyst for NO x removal.

    Science.gov (United States)

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

    2017-09-01

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

  8. Supported rhodium catalysts for ammonia-borane hydrolysis. Dependence of the catalytic activity on the highest occupied state of the single rhodium atoms

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Liangbing; Li, Hongliang; Zhang, Wenbo; Zhao, Xiao; Qiu, Jianxiang; Li, Aowen; Zheng, Xusheng; Zeng, Jie [Hefei National Lab. for Physical Sciences at the Microscale, Key Lab. of Strongly-Coupled Quantum Matter Physics, Chinese Academy of Sciences, Hefei, Anhui(China); Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui (China); Hu, Zhenpeng [School of Physics, Nankai University, Tianjin (China); Si, Rui [Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences (China)

    2017-04-18

    Supported metal nanocrystals have exhibited remarkable catalytic performance in hydrogen generation reactions, which is influenced and even determined by their supports. Accordingly, it is of fundamental importance to determine the direct relationship between catalytic performance and metal-support interactions. Herein, we provide a quantitative profile for exploring metal-support interactions by considering the highest occupied state in single-atom catalysts. The catalyst studied consisted of isolated Rh atoms dispersed on the surface of VO{sub 2} nanorods. It was observed that the activation energy of ammonia-borane hydrolysis changed when the substrate underwent a phase transition. Mechanistic studies indicate that the catalytic performance depended directly on the highest occupied state of the single Rh atoms, which was determined by the band structure of the substrates. Other metal catalysts, even with non-noble metals, that exhibited significant catalytic activity towards NH{sub 3}BH{sub 3} hydrolysis were rationally designed by adjusting their highest occupied states. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  9. Multi-stage catalyst systems and uses thereof

    Science.gov (United States)

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

    2009-02-10

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

  10. Ethanol electrooxidation on novel carbon supported Pt/SnOx/C catalysts with varied Pt:Sn ratio

    International Nuclear Information System (INIS)

    Jiang, L.; Colmenares, L.; Jusys, Z.; Sun, G.Q.; Behm, R.J.

    2007-01-01

    Novel carbon supported Pt/SnO x /C catalysts with Pt:Sn atomic ratios of 5:5, 6:4, 7:3 and 8:2 were prepared by a modified polyol method and characterized with respect to their structural properties (X-ray diffraction (XRD) and transmission electron microscopy (TEM)), chemical composition (XPS), their electrochemical properties (base voltammetry, CO ad stripping) and their electrocatalytic activity and selectivity for ethanol oxidation (ethanol oxidation reaction (EOR)). The data show that the Pt/SnO x /C catalysts are composed of Pt and tin oxide nanoparticles with an average Pt particle diameter of about 2 nm. The steady-state activity of the Pt/SnO x /C catalysts towards the EOR decreases with tin content at room temperature, but increases at 80 deg. C. On all Pt/SnO x /C catalysts, acetic acid and acetaldehyde represent dominant products, CO 2 formation contributes 1-3% for both potentiostatic and potentiodynamic reaction conditions. With increasing potential, the acetaldehyde yield decreases and the acetic acid yield increases. The apparent activation energies of the EOR increase with tin content (19-29 kJ mol -1 ), but are lower than on Pt/C (32 kJ mol -1 ). The somewhat better performance of the Pt/SnO x /C catalysts compared to alloyed PtSn x /C catalysts is attributed to the presence of both sufficiently large Pt ensembles for ethanol dehydrogenation and C-C bond splitting and of tin oxide for OH generation. Fuel cell measurements performed for comparison largely confirm the results obtained in model studies

  11. The role of reaction pathways and support interactions in the development of high activity hydrotreating catalysts

    DEFF Research Database (Denmark)

    Topsøe, Henrik; Hinnemann, Berit; Nørskov, Jens Kehlet

    2005-01-01

    structures may be present as single sulfide sheets. Thus, stacking is not an essential feature of Type II catalysts. The article illustrates how the new scientific insight has aided the introduction of the new high activity BRIM (TM) type catalysts for FCC pre-treatment and production of ultra low sulfur...... exhibiting a metallic character are observed to be involved in adsorption, hydrogenation and C-S bond cleavage. The insight is seen to provide a new framework for understanding the DDS and HYD pathways and the role of steric hindrance and poisons. Density functional theory (DFT) calculations have illustrated...... how support interactions may influence the activity of sulfided catalysts. The brim sites and the tendency to form vacancies are seen to differ in types I and II Co-Mo-S. High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) studies show that the high activity Type II...

  12. Hydrogen or synthesis gas production via the partial oxidation of methane over supported nickel-cobalt catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Koh, Alaric C.W. [Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543 (Singapore); Institute of Chemical and Engineering Sciences, 1 Pesek Road, Jurong Island, Singapore 627833 (Singapore); Chen, Luwei; Lin, Jianyi [Institute of Chemical and Engineering Sciences, 1 Pesek Road, Jurong Island, Singapore 627833 (Singapore); Kee Leong, Weng [Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543 (Singapore); Johnson, Brian F.G.; Khimyak, Tetyana [University Chemical Laboratory, University of Cambridge, Lensfield Road, Cambridge, UK CB2 1EW (United Kingdom)

    2007-05-15

    Activity, selectivity, and coking-resistance of a series of Ni{sub x}Co{sub y} (where x,y are the respective metal loadings of 0, 1, 2 or 3 wt.%; x+y=3) bimetallic catalysts supported on CaAl{sub 2}O{sub 4}/Al{sub 2}O{sub 3} have been studied for hydrogen/synthesis gas production via the catalytic partial oxidation (CPO) of methane. Catalysts were characterized by temperature programmed reduction (TPR), transmission electron microscopy (TEM) and X-ray fluorescence multi-element analysis (XRF). Their activity for the partial oxidation of methane to hydrogen and carbon monoxide (at 1 bar, gas hourly space velocity (GHSV) of 144,000cm{sup 3}g{sup -1}h{sup -1} and CH{sub 4}/O{sub 2} molar ratio of 2) was investigated, and coke deposited on the spent catalysts was studied by scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and thermogravimetric analysis (TGA). The activity was found to decrease in the order of Ni{sub 2}Co>Ni{sub 3}>NiCo{sub 2}>>Co{sub 3}, while CO and H{sub 2} selectivities were found to be in the order ofNi{sub 2}Co>Ni{sub 3}{approx}NiCo{sub 2}>Co{sub 3}. Ni{sub 2}Co is also shown to be more resistant to coking as compared to Ni{sub 3}, which is a current catalyst of choice. Results show that not only does Ni{sub 2}Co have the highest activity and selectivity among all the catalysts tested, it is also relatively resistant to coking. This finding would be helpful for catalyst design to achieve high coking resistivity catalysts for hydrogen production from CPO of methane. (author)

  13. Controlled Oxygen Chemisorption on an Alumina Supported Rhodium Catalyst. The Formation of a New Metal-Metal Oxide Interface Determined with EXAFS.

    NARCIS (Netherlands)

    Koningsberger, D.C.; Martens, J.H.A.; Prins, R.

    1989-01-01

    An alumina-supported rhodium catalyst has been studied with EXAFS. After reduction and evacuation, oxygen was admitted at 100 and 300 K. EXAFS spectra of the catalyst after oxygen admission at 100 K indicated the beginning of oxidation. At 300 K only a small part of the rhodium particles remained

  14. Catalytic conversion of CO, NO and SO2 on supported sulfide catalysts. Part 2. Catalytic reduction of NO and SO2 by CO

    International Nuclear Information System (INIS)

    Zhuang, S.-X.; Yamazaki, M.; Omata, K.; Takahashi, Y.; Yamada, M.

    2001-01-01

    To investigate the possibility of simultaneous catalytic reduction of NO and SO 2 by CO, reactions of NO, NO-CO, and NO-SO 2 -CO were performed on γ-alumina-supported sulfides of transition metals including Co, Mo, CoMo and FeMo. NO was decomposed into N 2 O and N 2 accompanied with the formation of SO 2 ; this serious oxidation of lattice sulfur resulted in the deactivation of the catalysts. The addition of CO to the NO stream suppressed SO 2 formation and yielded COS instead. A stoichiometric conversion of NO and CO to N 2 and CO 2 was observed above 350C on the CoMo and the FeMo catalysts. Although the CO addition lengthened catalyst life, it was not enough to maintain activity. After the NO-CO reaction, an XPS analysis showed the growth of Mo 6+ and SO 4 2- peaks, especially for the sulfided FeMo/Al 2 O 3 ; the FeMo catalyst underwent strong oxidation in the NO-CO reaction. The NO and the NO-CO reactions proceeded non-catalytically, consuming catalyst lattice sulfur to yield SO 2 or COS. The addition of SO 2 in the NO-CO system enabled in situ regeneration of the catalysts; the catalysts oxidized through abstraction of lattice sulfur experienced anew reduction and sulfurization through the SO 2 -CO reaction at higher temperature. NO and SO 2 were completely and catalytically converted at 400C on the sulfided CoMo/Al 2 O 3 . By contrast, the sulfided FeMo/Al 2 O 3 was easily oxidized by NO and hardly re-sulfided under the test conditions. Oxidation states of the metals before and after the reactions were determined. Silica and titania-supported CoMo catalysts were also evaluated to study support effects

  15. Molybdenum acetate like precursor of molybdenum carburized supported on alumina: a catalyst for hydrogenation reactions

    International Nuclear Information System (INIS)

    Petkovic, Lucia M; Parra, Ruben D; Marquez Manuel; Larsen, Gustavo

    1994-01-01

    The stability of the Al203 supported dimers under relatively high temperatures and hydrocarbon/H2 (carburizing) atmospheres is reported also, it has been developed a new method for Mo2 loading of the support based on the wet impregnation of the latter. Since carbided Mo is active for hydrogenations, the isobutene/H2 has been chosen as the probe reaction. Al203 supported Mo2(Ac)4 results in a catalyst active for isobutene hydrogenation after treatment with a H2/C2H6 2:1 mixture at 753 k

  16. Immersion Calorimetry for the Characterization of PD Catalysts Supported on Activated Carbon

    Directory of Open Access Journals (Sweden)

    Liliana Giraldo

    2009-01-01

    Full Text Available Activated carbons obtained from coconut peel were oxidized using hydrogen peroxide. Superficial characteristics of these carbons were determined through N2 and CO2 isotherms and functional groups were characterized by TPD. Finally, the microcalorimetry technique was used in order to obtain the immersion enthalpies in diverse liquids and established the relation between them and the results obtained by the other characterization techniques. The results suggested that the immersion calorimetry allow establishing the difference between the supports and the catalysts.

  17. 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...... membrane fuel cell based on H3PO4-doped PBI for operation at temperatures between 150 and 200 degrees C. (C) 2000 Elsevier Science Ltd. All rights reserved....

  18. Size-dependent effects in supported highly dispersed Fe2O3 catalysts, doped with Pt and Pd

    International Nuclear Information System (INIS)

    Cherkezova-Zheleva, Zara; Shopska, Maya; Mitov, Ivan; Kadinov, Georgi

    2010-01-01

    Series of Fe and Fe–Me (Me = Pt or Pd) catalyst supported on γ-Al 2 O 3 , TiO 2 (anatase) or diatomite were prepared by the incipient wetness impregnation method. The metal loading was 8 wt.% Fe and 0.7 wt.% noble metal. The preparation and pretreatment conditions of all studied samples were kept to be the same. X-ray diffraction, Moessbauer spectroscopy, X-ray photoelectron spectroscopy and temperature-programmed reduction are used for characterization of the supports and the samples at different steps during their treatment and catalytic tests. The catalytic activity of the samples was tested in the reaction of total benzene oxidation. The physicochemical and catalytic properties of the obtained materials are compared with respect of the different chemical composition, dispersion of used carriers and of the supported phases. Samples with the same composition prepared by mechanical mixing are studied as catalysts for comparison and for clearing up the presence of size-dependent effect, also.

  19. 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

    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...

  20. Electrocatalytic activity of carbon-supported catalysts for direct ethanol fuel cell applications

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez Varela, F.J. [CINVESTAV-Unidad Saltillo, Coahuila, (Mexico). Grupo de Investigacion en Energia; Savadogo, O. [Ecole Polytechnique de Montreal, Montreal, PQ (Canada). Laboratoire de nouveaux materiaux pour l' energie et l' electrochimie

    2008-07-01

    Proton exchange membrane fuel cells (PEMFCs) can be fueled with hydrogen, alcohols, hydrocarbons and acetals. Ethanol is an important fuel candidate because it can be electro-oxidized to carbon dioxide on platinum (Pt)-based electrocatalysts in a direct ethanol fuel cell (DEFC) at relatively low temperatures. This study investigated the electrocatalytic activity of some carbon-supported electrocatalysts towards the ethanol oxidation (EOR) and the oxygen reduction reaction (ORR) in the presence of ethanol. Compared to other anode catalysts such as Pt, PtRu and Pt oxide, anodes based on PtSn alloys have a higher catalytic activity for the EOR. When tested in a DEFC, the current density at 0.4V and 90 degrees C based on a PtSn/C anode and a Pt/C cathode was 2 times higher than that of a cell based on a PtRu/C-Pt/C membrane electrode assembly (MEA) configuration. In addition, cathode catalysts based on Ru/C had good catalytic activity for the ORR and exhibited high selectivity for this reaction in the presence of ethanol. The results showed that in the presence of 0.125, 0.25 or 0.5 M ethanol concentrations, a decrease in onset potential of about 60, 62 and 68 mV emerged, respectively. These values were about 10 times lower than those measured for some Pt-based cathode catalysts tested in this study in the presence of 0.125 M EtOH. 20 refs., 5 figs.

  1. 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.

  2. Synthesis and characterization of alumina-supported vanadium oxide catalysts prepared by the molecular designed dispersion of VO(acac)2 complexes

    NARCIS (Netherlands)

    Weckhuysen, B.M.; Baltes, M.; Voort, P. van der; Ramachandra Rao, R.; Catana, Gabriela; Schoonheydt, R.A.; Vansant, E.F.

    2000-01-01

    Alumina-supported vanadium oxide catalysts have been prepared by the molecular designed dispersion method, using the vanadyl acetylacetonate complex (VO(acac)2). The complex has been adsorbed on the support from solution, followed by thermal conversion into the corresponding supported vanadium oxide

  3. HDO of guaiacol over NiMo catalyst supported on activated carbon derived from castor de-oiled cake

    Directory of Open Access Journals (Sweden)

    Viviana Ospina

    2015-05-01

    Full Text Available Physical and chemical activation methods were used to prepare two different activated carbons (ACs from castor de-oiled cake. H2O/CO2 mixture was used as the physical activating agent, and for chemical activation potassium carbonate (K2CO3 was used. For both materials, textural and chemical properties were characterized by N2 adsorption–desorption isotherms, thermogravimetric analysis (TGA, Fourier Transform Infrared Spectroscopy (FTIR, thermal programmed reduction (TPR, X-ray fluorescence (XRF, and scanning electron microscopy (SEM. The ACs were used as supports for NiMo sulfide catalysts, which were prepared by wetness impregnation and in-situ sulfided for the hydrodeoxygenation (HDO of guaiacol (GUA as a model compound of bio-oil. The HDO reaction was carried out in a typical batch reactor at 5 MPa of H2 and 350 °C. Under the same test conditions, commercial catalysts were also tested in the reaction. Although the commercial catalysts displayed higher GUA conversion, the prepared catalysts showed higher activity and non-oxygenated and saturated products yield.

  4. Synthesis of gold nano-catalysts supported on carbon nanotubes by using electroless plating technique

    International Nuclear Information System (INIS)

    Ma Xicheng; Li Xia; Lun Ning; Wen Shulin

    2006-01-01

    Gold nanoparticles supported on carbon nanotubes were prepared by using electroless plating technique. High-resolution transmission electron microscopy (HRTEM) has shown that spherical gold nanoparticles were homogeneously dispersed on the surfaces of the carbon nanotubes with a distribution of particle sizes sharply at around 3-4 nm in diameter. The results presented in this work will probably provide new catalysts with better performances

  5. Mesoporous TiO2 : an alternative material for PEM fuel cells catalyst support

    Energy Technology Data Exchange (ETDEWEB)

    Do, T.B. [Michigan Univ., Ann Arbor, MI (United States). Dept. of Materials Science; Ruthkosky, M.; Cai, M. [General Motors, Warren, MI (United States). Research and Development Center

    2008-07-01

    This paper discussed the feasibility of using an alternative catalyst support material to replace carbon in proton exchange membrane (PEM) fuel cells. The alternative catalyst support material requires a high surface area with a large porosity but must have comparable conductivity with carbon. A mesoporous titanium oxide (TiO2) material produced by coprecipitation was introduced. The conductivity of the material is about one order of that of carbon. The 8 mole per cent Nb-doped TiO2 was formed and deposited on the surface of a nano polystyrene (PS) template via the hydrolysis of a co-solution of Ti(OC4H9)4 and Nb(OC2H5)5. The removal of PS by heat treatment produced porous structure of TiO2 with the appearance of 3 different pore types, notably open pore, ink-pot pores and closed pores. TiO2 formed from the rutile phase, allowing a lower activation temperature at 850 degrees C in a hydrogen atmosphere. The pore structures were retained after this heat treatment. The BET surface area was 116 m{sup 2}/g, porosity was 22 per cent and the average pore size was 159 angstrom. The conductivity improved considerably from almost non-conductive to one order of that of carbon.

  6. Hydrodeoxygenation of Methyl Laurate over Ni Catalysts Supported on Hierarchical HZSM-5 Zeolite

    Directory of Open Access Journals (Sweden)

    Nana Li

    2017-12-01

    Full Text Available The hierarchical HZSM-5 zeolite was prepared successfully by a simple NaOH treatment method. The concentration of NaOH solution was carefully tuned to optimal the zeolite acidity and pore structure. Under NaOH treatment conditions, a large number of mesopores, which interconnected with the retained micropores, were created to facilitate mass transfer performance. There are very good correlations between the decline of the relative zeolite crystallinity and the loss of micropores volume. The Ni nanoclusters were uniformly confined in the mesopores of hierarchical HZSM-5 by the excessive impregnation method. The direct deoxygenation in N2 and hydrodeoxygenation in H2 of the methyl laurate were compared respectively over the Ni/HZSM-5 catalysts. In the N2 atmosphere, the deoxygenation rate of the methyl laurate on the Ni/HZSM-5 catalyst is relatively slow. In the presence of H2, the synergistic effect between the hydrogenation function of the metal and the acid function of the zeolite supports can make the deoxygenation level more obvious. The yield of hydrocarbon products gradually reached the maximum with the appropriate treatment concentration of 1M NaOH, which could be attributed to the improved mass transfer in the hierarchical HZSM-5 supports.

  7. Vertically-oriented graphenes supported Mn3O4 as advanced catalysts in post plasma-catalysis for toluene decomposition

    Science.gov (United States)

    Bo, Zheng; Hao, Han; Yang, Shiling; Zhu, Jinhui; Yan, Jianhua; Cen, Kefa

    2018-04-01

    This work reports the catalytic performance of vertically-oriented graphenes (VGs) supported manganese oxide catalysts toward toluene decomposition in post plasma-catalysis (PPC) system. Dense networks of VGs were synthesized on carbon paper (CP) via a microwave plasma-enhanced chemical vapor deposition (PECVD) method. A constant current approach was applied in a conventional three-electrode electrochemical system for the electrodeposition of Mn3O4 catalysts on VGs. The as-obtained catalysts were characterized and investigated for ozone conversion and toluene decomposition in a PPC system. Experimental results show that the Mn3O4 catalyst loading mass on VG-coated CP was significantly higher than that on pristine CP (almost 1.8 times for an electrodeposition current of 10 mA). Moreover, the decoration of VGs led to both enhanced catalytic activity for ozone conversion and increased toluene decomposition, exhibiting a great promise in PPC system for the effective decomposition of volatile organic compounds.

  8. Molecular and Silica-Supported Molybdenum Alkyne Metathesis Catalysts: Influence of Electronics and Dynamics on Activity Revealed by Kinetics, Solid-State NMR, and Chemical Shift Analysis.

    Science.gov (United States)

    Estes, Deven P; Gordon, Christopher P; Fedorov, Alexey; Liao, Wei-Chih; Ehrhorn, Henrike; Bittner, Celine; Zier, Manuel Luca; Bockfeld, Dirk; Chan, Ka Wing; Eisenstein, Odile; Raynaud, Christophe; Tamm, Matthias; Copéret, Christophe

    2017-12-06

    Molybdenum-based molecular alkylidyne complexes of the type [MesC≡Mo{OC(CH 3 ) 3-x (CF 3 ) x } 3 ] (MoF 0 , x = 0; MoF 3 , x = 1; MoF 6 , x = 2; MoF 9 , x = 3; Mes = 2,4,6-trimethylphenyl) and their silica-supported analogues are prepared and characterized at the molecular level, in particular by solid-state NMR, and their alkyne metathesis catalytic activity is evaluated. The 13 C NMR chemical shift of the alkylidyne carbon increases with increasing number of fluorine atoms on the alkoxide ligands for both molecular and supported catalysts but with more shielded values for the supported complexes. The activity of these catalysts increases in the order MoF 0 molecular and supported species. Detailed solid-state NMR analysis of molecular and silica-supported metal alkylidyne catalysts coupled with DFT/ZORA calculations rationalize the NMR spectroscopic signatures and discernible activity trends at the frontier orbital level: (1) increasing the number of fluorine atoms lowers the energy of the π*(M≡C) orbital, explaining the more deshielded chemical shift values; it also leads to an increased electrophilicity and higher reactivity for catalysts up to MoF 6 , prior to a sharp decrease in reactivity for MoF 9 due to the formation of stable metallacyclobutadiene intermediates; (2) the silica-supported catalysts are less active than their molecular analogues because they are less electrophilic and dynamic, as revealed by their 13 C NMR chemical shift tensors.

  9. The support effect of the Mn-Na{sub 2}WO{sub 4}/SiO{sub 2} catalyst in the oxidative coupling of methane

    Energy Technology Data Exchange (ETDEWEB)

    Yildiz, M.; Arndt, S.; Simon, U.; Aksu, Y.; Schubert, H.; Schomaecker, R. [Technische Univ. Berlin (Germany)

    2011-07-01

    Methane is the major component of natural gas with known resources rivaling those of crude oil. Therefore, a direct conversion of CH{sub 4} into value added products is of strong interest for the chemical industry. One suitable reaction is the oxidative coupling of methane, which has received great attention since the first publications. Despite the intensive research, this process is not applied yet due to a lack of active and stable catalysts. A promising candidate is the Mn-Na{sub 2}WO{sub 4}/SiO{sub 2} catalyst, which is known for its high selectivity and its remarkable stability. Although there are some suggestions on the role of the different components, the support material and the phase of the support material, reliable facts are rare for this catalyst. For this reason we carried out a wide-range variation of the support material (e.g. ZrO{sub 2}, Fe{sub 2}O{sub 3}, TiO{sub 2}, Al{sub 2}O{sub 3}, MgO, etc.) to reveal its effect to the activity and the stability. The prepared catalysts were characterized by BET surface area and X-ray diffraction analysis and the OCM was performed in a packed-bed reactor with respect to long term stability. We found that the catalyst is active in the OCM even without SiO{sub 2} as support material, questioning the current suggestions for the active center. (orig.)

  10. Direct fabrication of metal-free hollow graphene balls with a self-supporting structure as efficient cathode catalysts of fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Yanqi; Liu, Mingda; Nie, Huagui, E-mail: huaguinie@126.com; Gu, Cancan; Liu, Ming; Yang, Zhi, E-mail: yang201079@126.com; Yang, Keqin; Chen, Xi’an; Huang, Shaoming, E-mail: smhuang@wzu.edu.cn [Wenzhou University, Nanomaterials and Chemistry Key Laboratory (China)

    2016-06-15

    Despite the good progress in developing carbon catalysts for oxygen reduction reaction (ORR), the current metal-free carbon catalysts are still far from satisfactory for large-scale applications of fuel cell. Developing hollow graphene balls with a self-supporting structure is considered to be an ideal method to inhibit graphene stacking and improve their catalytic performance. Herein, we fabricated metal-free hollow graphene balls with a self-supporting structure, through using a new strategy that involves direct metal-free catalytic growth from assembly of SiO{sub 2} spheres. To our knowledge, although much researches involving the synthesis of graphene balls have been reported, investigations into the direct metal-free catalytic growth of hollow graphene balls are rare. Furthermore, the electrocatalytic performance shows that the resulting hollow graphene balls have significantly high catalytic activity. More importantly, such catalysts also possess much improved stability and better methanol tolerance in alkaline media during the ORR compared with commercial Pt/C catalysts. The outstanding performances coupled with an easy and inexpensive preparing method indicated the great potential of the hollow graphene balls with a self-supporting structure in large-scale applications of fuel cell.Graphical AbstractHollow graphene balls with a self-supporting structure have been successfully fabricated, through using a new strategy that involves direct metal-free catalytic growth from 3D assembly of SiO{sub 2} spheres. The hollow graphene balls can exhibit a high catalytic activity, long-term stability, and an excellent methanol tolerance for the oxygen reduction reaction.

  11. Direct fabrication of metal-free hollow graphene balls with a self-supporting structure as efficient cathode catalysts of fuel cell

    International Nuclear Information System (INIS)

    Lu, Yanqi; Liu, Mingda; Nie, Huagui; Gu, Cancan; Liu, Ming; Yang, Zhi; Yang, Keqin; Chen, Xi’an; Huang, Shaoming

    2016-01-01

    Despite the good progress in developing carbon catalysts for oxygen reduction reaction (ORR), the current metal-free carbon catalysts are still far from satisfactory for large-scale applications of fuel cell. Developing hollow graphene balls with a self-supporting structure is considered to be an ideal method to inhibit graphene stacking and improve their catalytic performance. Herein, we fabricated metal-free hollow graphene balls with a self-supporting structure, through using a new strategy that involves direct metal-free catalytic growth from assembly of SiO_2 spheres. To our knowledge, although much researches involving the synthesis of graphene balls have been reported, investigations into the direct metal-free catalytic growth of hollow graphene balls are rare. Furthermore, the electrocatalytic performance shows that the resulting hollow graphene balls have significantly high catalytic activity. More importantly, such catalysts also possess much improved stability and better methanol tolerance in alkaline media during the ORR compared with commercial Pt/C catalysts. The outstanding performances coupled with an easy and inexpensive preparing method indicated the great potential of the hollow graphene balls with a self-supporting structure in large-scale applications of fuel cell.Graphical AbstractHollow graphene balls with a self-supporting structure have been successfully fabricated, through using a new strategy that involves direct metal-free catalytic growth from 3D assembly of SiO_2 spheres. The hollow graphene balls can exhibit a high catalytic activity, long-term stability, and an excellent methanol tolerance for the oxygen reduction reaction

  12. Effect of niobium addition in support catalysts applied in satellite propulsion

    Energy Technology Data Exchange (ETDEWEB)

    Soares, M.S., E-mail: marciosteinmetz@hotmail.com.br [Space Research National Institute, Combustion & Propulsion Associated Laboratory (Brazil); University of São Paulo, Lorena Engineering School, Materials Engineering Dept. (Brazil); Barbosa, R.D. [Space Research National Institute, Combustion & Propulsion Associated Laboratory (Brazil); University of São Paulo, Lorena Engineering School, Chemical Engineering Dept. (Brazil); Cruz, G.M. da; Rodrigues, J.A.J. [Space Research National Institute, Combustion & Propulsion Associated Laboratory (Brazil); Ribeiro, S. [University of São Paulo, Lorena Engineering School, Materials Engineering Dept. (Brazil)

    2017-03-01

    Catalysts composed of iridium as the active phase dispersed in aluminum oxide (Ir/Al{sub 2}O{sub 3}) are used in propulsion systems that employ hydrazine as monopropellant in the control of satellite orbit and attitude. The aluminum oxide (Al{sub 2}O{sub 3}) utilized as support must present high values of specific surface area, pore volume, and crush strength. The niobium effect was evaluated in this work, in its oxide form (Nb{sub 2}O{sub 5}), by 3 different methods: with the employment of a NbCl{sub 5} precursor solution, by wet impregnation and dry impregnation of an alumina obtained from a mixture of gibbsite and boehmite and by physical mixing of gibbsite and hydrated niobium oxide, both autoclaved separately. Aluminum oxides were prepared in both cases containing Nb{sub 2}O{sub 5} contents of 10, 20, and 30% w/w. The acid impregnating NbCl{sub 5} solution in the wet impregnation method caused a strong attack to the Al{sub 2}O{sub 3} support, altering and compromising its initial structure and morphology. This process did not occur in the supports prepared by dry impregnation. However, results indicated that the use of this methodology with Nb{sub 2}O{sub 5} contents of 20% and 30%, caused an extensive coverage of the support by Nb{sub 2}O{sub 5}, modifying the nature and amount of alumina sites responsible for anchorage of the iridium precursor. In the case of supports prepared through physical mixture (Nb{sub 2}O{sub 5}-Al{sub 2}O{sub 3}) from aluminum hydroxide and niobium acid precursor compounds, with both being previously autoclaved separately, the 20% and 30% Nb{sub 2}O{sub 5} contents presented the most promising properties, since the binder effect caused by amorphous Nb{sub 2}O{sub 5} increased the crush strength of the support, without compromising the aluminum oxide morphology and texture. Despite of existence of stronger acid sites due to the addition of niobium oxide to aluminum oxide, no increase in the acidity of the materials was observed due

  13. Investigation of the supported nickel catalysts by XAS and XRD, using synchrotron radiation

    International Nuclear Information System (INIS)

    Aldea, N.; Marginean, P.; Gluhoi, A.; Yaning, Xie; Dong, Bazohong

    2001-01-01

    In the first part of the paper we present a study based on EXAFS spectroscopy. This method can yield structural information about the local environment around a specific atomic constituent in the amorphous materials, the location and chemical state of any catalytic atom on any support or point defect structures in alloys and composites. EXAFS is a specific technique of the scattering of X-ray on materials. The present study is aimed toward elucidating the local structure of Ni atoms and their interaction with oxide support. In this case, we analyse the first three shells of coordination. The second aim of the paper consists in X-ray diffraction on the same samples. X-ray diffraction method which is capable to determine average particle size, microstrains, probability of faults as well as particle size distribution function of supported Ni catalysts is presented. The method is based on the Fourier analysis of X-Ray diffraction profiles such as (111) (200) and (220). We are going to work out a chemisorption model by the correlation of the local and global structure connected with the specific surface. On the other hand, we will try to estimate specific surface values determined by classical method with occupation factor evaluated by the geometrical Ni clusters. The results obtained on supported nickel catalysts which are used in H/D isotopic exchange reactions are reported. The global structure is obtained with a new fitting method based on the Generalised Fermi Function facilities for approximation and Fourier transform of the experimental X-Ray line profiles. Both types of measurements were performed on Beijing Synchrotron Radiation Facilities (BSRF). (authors)

  14. 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.

  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

    2014-01-01

    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 toward citronellal was achieved over a catalyst containing the alkaline ionic liquid benzalkonium methoxide. PMID:24790972

  16. Catalysts for synthetic liquid fuels

    Energy Technology Data Exchange (ETDEWEB)

    Bruce, L.A.; Turney, T.W.

    1987-12-01

    Fischer-Tropsch catalysts have been designed, characterized and tested for the selective production of hydrocarbons suitable as synthetic liquid transport fuels from synthesis gas (i.e., by the reduction of carbon monoxide with hydrogen). It was found that hydrocarbons in the middle distillate range, or suitable for conversion to that range, could be produced over several of the new catalyst systems. The various catalysts examined included: (1) synthetic cobalt clays, mainly cobalt chlorites; (2) cobalt hydrotalcites; (3) ruthenium metal supported on rare earth oxides of high surface area; and (4) a novel promoted cobalt catalyst. Active and selective catalysts have been obtained, in each category. With the exception of the clays, reproducibility of catalyst performance has been good. Catalysts in groups 2 and 4 have exhibited very high activity, with long lifetimes and easy regeneration.

  17. Productions of palm oil bio diesel whit heterogeneous basic catalysts compared to conventional homogeneous catalysts

    International Nuclear Information System (INIS)

    Rios, Luis A; Franco C, Alexander; Zuleta S, Ernesto

    2009-01-01

    The conventional process to produce biodiesel involves the presence of homogeneous basic catalysts. However, these catalysts have disadvantages associated to the need of purification steps, which increase the cost of the final product and generate pollution problems caused by the effluents. This paper compares different homogeneous and heterogeneous catalysts for the biodiesel production from palm oil. For this, heterogeneous catalysts supported on alumina were prepared and characterized by nitrogen adsorption, scanning electron microscopy, energy dispersive X ray spectroscopy and X ray diffraction. Transesterification of palm oil with methanol was accomplished at 60 celsius degrade and one hour, varying methanol/oil ratio, the type of catalyst and its concentration. Yields of the reaction and purity of the so obtained biodiesel were evaluated. Comparing the catalysts performance, based on the amount, was found that sodium methoxide (CH 3 ONa) and potassium carbonate supported on alumina (K 2 CO 3 /Al 2 O 3 ) were the catalysts that give the higher purity of biodiesel (96.8 and 95.85% respectively). When was determined the active site quality, by dividing the performance by each mole of active sites, it was found that calcined Na 2 SO 4 /Al 2 O 3 has the most active sites.

  18. 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.

  19. Tailoring the properties of Platinum supported catalysts by irreversible adsorbed adatoms toward ethanol oxidation for direct ethanol fuel cells

    OpenAIRE

    Costa Figueiredo, Marta; Santasalo-Aarnio, A.; Vidal-Iglesias, F.J.; Solla-Gullón, J.; Feliu, J.M.; Kontturi, K.; Kallio, T.

    2013-01-01

    In this work ethanol oxidation on carbon supported Pt catalysts modified with irreversibly adsorbed adatoms is reported. This study concerns understanding of the effect of a second metal on real catalysts in conditions as close as possible to those applied in fuel cells systems. The results were acquired using cyclic voltammetry, chronoamperometry and in situ infra-red techniques always taking into account the future application of the electrocatalyst materials in fuel cells. Foreign adatoms,...

  20. CH{sub 4} reforming with CO{sub 2} for syngas production over nickel catalysts supported on mesoporous nanostructured γ-Al{sub 2}O{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Majidian, Nasrollah; Habibi, Narges [Islamic Azad University, Tehran (Iran, Islamic Republic of); Rezaei, Mehran [University of Kashan, Kashan (Iran, Islamic Republic of)

    2014-07-15

    Nanostructured γ-Al{sub 2}O{sub 3} with high surface area and mesoporous structure was synthesized by sol-gel method and employed as catalyst support for nickel catalysts in methane reforming with carbon dioxide. The prepared samples were characterized by XRD, BET, TPR, TPH, SEM and TPO techniques. The BET analysis showed a high surface area of 204m{sup 2}g{sup -1} and a narrow pore-size distribution centered at a diameter of 5.5 nm for catalyst support. The results revealed that an increase in nickel loading from 5 to 15 wt% decreased the surface area of catalyst from 182 to 160 m{sup 2}g{sup -1}. In addition, the catalytic results showed an increase in methane conversion with increase in nickel content. TPO analysis revealed that the coke deposition increased with increasing in nickel loading, and the catalyst with 15 wt% of nickel showed the highest degree of carbon formation. SEM and TPH analyses confirmed the formation of whisker type carbon over the spent catalysts. Increasing CO{sub 2}/CH{sub 4} ratio increased the methane conversion. The BET analysis of spent catalysts indicated that the mesoporous structure of catalysts still remained after reaction.

  1. 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...

  2. 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...

  3. Hydrodeoxygenation of vicinal OH groups over heterogeneous rhenium catalyst promoted by palladium and ceria support.

    Science.gov (United States)

    Ota, Nobuhiko; Tamura, Masazumi; Nakagawa, Yoshinao; Okumura, Kazu; Tomishige, Keiichi

    2015-02-02

    Heterogeneous ReOx-Pd/CeO2 catalyst showed excellent performance for simultaneous hydrodeoxygenation of vicinal OH groups. High yield (>99%), turnover frequency (300 h(-1)), and turnover number (10,000) are achieved in the reaction of 1,4-anhydroerythritol to tetrahydrofuran. This catalyst can be applied to sugar alcohols, and mono-alcohols and diols are obtained in high yields (≥85%) from substrates with even and odd numbers of OH groups, respectively. The high catalytic performance of ReOx-Pd/CeO2 can be assigned to rhenium species with +4 or +5 valence state, and the formation of this species is promoted by H2/Pd and the ceria support. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  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. Role of bonding mechanisms during transfer hydrogenation reaction on heterogeneous catalysts of platinum nanoparticles supported on zinc oxide nanorods

    Science.gov (United States)

    Al-Alawi, Reem A.; Laxman, Karthik; Dastgir, Sarim; Dutta, Joydeep

    2016-07-01

    For supported heterogeneous catalysis, the interface between a metal nanoparticle and the support plays an important role. In this work the dependency of the catalytic efficiency on the bonding chemistry of platinum nanoparticles supported on zinc oxide (ZnO) nanorods is studied. Platinum nanoparticles were deposited on ZnO nanorods (ZnO NR) using thermal and photochemical processes and the effects on the size, distribution, density and chemical state of the metal nanoparticles upon the catalytic activities are presented. The obtained results indicate that the bonding at Pt-ZnO interface depends on the deposition scheme which can be utilized to modulate the surface chemistry and thus the activity of the supported catalysts. Additionally, uniform distribution of metal on the catalyst support was observed to be more important than the loading density. It is also found that oxidized platinum Pt(IV) (platinum hydroxide) provided a more suitable surface for enhancing the transfer hydrogenation reaction of cyclohexanone with isopropanol compared to zero valent platinum. Photochemically synthesized ZnO supported nanocatalysts were efficient and potentially viable for upscaling to industrial applications.

  6. Preparative characteristics of hydrophobic polymer catalyst for the tritium removal

    International Nuclear Information System (INIS)

    Kang, Hee Suk; Choi, H. J.; Lee, H. S.; Ahn, D. H.; Kim, K. R.; Paek, S. W.; Paek, S. W.; Kim, J. G.; Chung, H. S.

    2001-05-01

    The optimum method for the fabrication of hydrophobic catalyst was selected and the apparatuses for the preparation of catalyst support with high yield was developed for the large scale production. Also, we summarized the method of improving the physical property of the catalyst support, the loading characteristics of Pt metal as a catalyst, and the characteristics of the apparatus for the fabrication of the catalysts on a large scale

  7. Preparative characteristics of hydrophobic polymer catalyst for the tritium removal

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Hee Suk; Choi, H. J.; Lee, H. S.; Ahn, D. H.; Kim, K. R.; Paek, S. W.; Kim, J. G.; Chung, H. S

    2001-05-01

    The optimum method for the fabrication of hydrophobic catalyst was selected and the apparatuses for the preparation of catalyst support with high yield was developed for the large scale production. Also, we summarized the method of improving the physical property of the catalyst support, the loading characteristics of Pt metal as a catalyst, and the characteristics of the apparatus for the fabrication of the catalysts on a large scale.

  8. Hydroformylation of 1-Hexene over Rh/Nano-Oxide Catalysts

    Directory of Open Access Journals (Sweden)

    Sari Suvanto

    2013-03-01

    Full Text Available The effect of nanostructured supports on the activity of Rh catalysts was studied by comparing the catalytic performance of nano- and bulk-oxide supported Rh/ZnO, Rh/SiO2 and Rh/TiO2 systems in 1-hexene hydroformylation. The highest activity with 100% total conversion and 96% yield of aldehydes was obtained with the Rh/nano-ZnO catalyst. The Rh/nano-ZnO catalyst was found to be more stable and active than the corresponding rhodium catalyst supported on bulk ZnO. The favorable morphology of Rh/nano-ZnO particles led to an increased metal content and an increased number of weak acid sites compared to the bulk ZnO supported catalysts. Both these factors favored the improved catalytic performance. Improvements of catalytic properties were obtained also with the nano-SiO2 and nano-TiO2 supports in comparison with the bulk supports. All of the catalysts were characterized by scanning electron microscope (SEM, inductively coupled plasma mass spectrometry (ICP-MS, BET, powder X-ray diffraction (PXRD and NH3- temperature-programmed desorption (TPD.

  9. Reduction of Furfural to Furfuryl Alcohol in Liquid Phase over a Biochar-Supported Platinum Catalyst

    Directory of Open Access Journals (Sweden)

    Ariadna Fuente-Hernández

    2017-02-01

    Full Text Available In this work, the liquid phase hydrogenation of furfural has been studied using a biochar-supported platinum catalyst in a batch reactor. Reactions were performed between 170 °C and 320 °C, using 3 wt % and 5 wt % of Pt supported on a maple-based biochar under hydrogen pressure varying from 500 psi to 1500 psi for reaction times between 1 h and 6 h in various solvents. Under all reactive conditions, furfural conversion was significant, whilst under specific conditions furfuryl alcohol (FA was obtained in most cases as the main product showing a selectivity around 80%. Other products as methylfuran (MF, furan, and trace of tetrahydrofuran (THF were detected. Results showed that the most efficient reaction conditions involved a 3% Pt load on biochar and operations for 2 h at 210 °C and 1500 psi using toluene as solvent. When used repetitively, the catalyst showed deactivation although only a slight variation in selectivity toward FA at the optimal experimental conditions was observed.

  10. Comparative study of activated carbon, natural zeolite, and green sand supports for CuOX and ZnO sites as ozone decomposition catalyst

    Science.gov (United States)

    Azhariyah, A. S.; Pradyasti, A.; Dianty, A. G.; Bismo, S.

    2018-03-01

    This research was based on ozone decomposition in industrial environment. Ozone is harmful to human. Therefore, catalysts were made as a mask filter to decompose ozone. Comparison studies of catalyst supports were done using Granular Activated Carbon (GAC), Natural Zeolite (NZ), and Green Sand (GS). GAC showed the highest catalytic activity compared to other supports with conversion of 98%. Meanwhile, the conversion using NZ was only 77% and GS had been just 27%. GAC had the highest catalytic activity because it had the largest pore volume, which is 0.478 cm3/g. So GAC was used as catalyst supports. To have a higher conversion in ozone decomposition, GAC was impregnated with metal oxide as the active site of the catalyst. Active site comparison was made using CuOX and ZnO as the active site. Morphology, composition, and crystal phase were analyzed using SEM-EDX, XRF, and XRD methods. Mask filter, which contained catalysts for ozone decomposition, was tested using a fixed bed reactor at room temperature and atmospheric pressure. The result of conversion was analyzed using iodometric method. CuOX/GAC and ZnO/GAC 2%-w showed the highest catalytic activity and conversion reached 100%. From the durability test, CuOX/GAC 2%-w was better than ZnO/GAC 2%-w because the conversion of ozone to oxygen reached 100% with the lowest conversion was 70% for over eight hours.

  11. On the metal-support synergy for selective gas-phase ethanol oxidation over MgCuCr2O4 supported metal nanoparticle catalysts

    NARCIS (Netherlands)

    Liu, P.; Zhu, X.; Yang, S.; Li, T.; Hensen, E.J.M.

    2015-01-01

    Achieving high yields in the production of bulk chemicals is an important goal for the chemical industry. We investigated the influence of the metal on the catalytic performance of M/MgCuCr2O4 (M = Cu, Ag, Pd, Pt, Au) catalysts to better understand the metal-support synergy for the aerobic oxidation

  12. Continuous Process for Biodiesel Production in Packed Bed Reactor from Waste Frying Oil Using Potassium Hydroxide Supported on Jatropha curcas Fruit Shell as Solid Catalyst

    Directory of Open Access Journals (Sweden)

    Achanai Buasri

    2012-08-01

    Full Text Available The transesterification of waste frying oil (WFO with methanol in the presence of potassium hydroxide catalyst supported on Jatropha curcas fruit shell activated carbon (KOH/JS was studied. The catalyst systems were characterized by X-ray diffraction (XRD, scanning electron microscopy (SEM and the Brunauer–Emmett–Teller (BET method. The effects of reaction variables such as residence time, reaction temperature, methanol/oil molar ratio and catalyst bed height in packed bed reactor (PBR on the yield of biodiesel were investigated. SEM images showed that KOH was well distributed on the catalyst support. The optimum conditions for achieving the conversion yield of 86.7% consisted of a residence time of 2 h, reaction temperature of 60 °C, methanol/oil molar ratio of 16 and catalyst bed height of 250 mm. KOH/JS could be used repeatedly five times without any activation treatment, and no significant activity loss was observed. The results confirmed that KOH/JS catalyst had a great potential to be used for industrial application in the transesterification of WFO. The fuel properties of biodiesel were also determined.

  13. Hydrodeoxygenation of Levulinic Acid over Supported Catalysts

    NARCIS (Netherlands)

    Luo, Wenhao|info:eu-repo/dai/nl/341385972

    2014-01-01

    Levulinic acid (LA), which can be produced from the sugar fractions of lignocellulosic biomass, is a promising sustainable platform molecule that can play a major role in future biorefineries. The work described was aimed at the development of heterogeneous catalysts for the selective conversion of

  14. Sinter-Resistant Platinum Catalyst Supported by Metal-Organic Framework

    Energy Technology Data Exchange (ETDEWEB)

    Kim, In Soo [Materials Science Division, Argonne National Lab, 9700 S Cass Ave. Argonne IL 60439 USA; Nanophotonics Center, Korea Institute of Science and Technology, Seoul 02792 South Korea; Li, Zhanyong [Department of Chemistry, Northwestern University, 2145 Sheridan Rd. Evanston IL 60208 USA; Zheng, Jian [Institute for Integrated Catalysis, Pacific Northwest National Lab, P.O. Box 999 Richland WA 99352 USA; Platero-Prats, Ana E. [X-ray Science Division, Argonne National Lab, 9700 S Cass Ave. Argonne IL 60439 USA; Mavrandonakis, Andreas [Department of Chemistry, University of Minnesota, 207 Pleasant St. SE Minneapolis MN 55455 USA; Pellizzeri, Steven [Chemical and Biomolecular Engineering, Clemson University, 205 Earle Hall Clemson SC 29634 USA; Ferrandon, Magali [Chemical Sciences and Engineering Division, Argonne National Lab, 9700 S. Cass Ave. Argonne IL 60439 USA; Vjunov, Aleksei [Institute for Integrated Catalysis, Pacific Northwest National Lab, P.O. Box 999 Richland WA 99352 USA; Gallington, Leighanne C. [X-ray Science Division, Argonne National Lab, 9700 S Cass Ave. Argonne IL 60439 USA; Webber, Thomas E. [Department of Chemistry, University of Minnesota, 207 Pleasant St. SE Minneapolis MN 55455 USA; Vermeulen, Nicolaas A. [Department of Chemistry, Northwestern University, 2145 Sheridan Rd. Evanston IL 60208 USA; Penn, R. Lee [Department of Chemistry, University of Minnesota, 207 Pleasant St. SE Minneapolis MN 55455 USA; Getman, Rachel B. [Chemical and Biomolecular Engineering, Clemson University, 205 Earle Hall Clemson SC 29634 USA; Cramer, Christopher J. [Department of Chemistry, University of Minnesota, 207 Pleasant St. SE Minneapolis MN 55455 USA; Chapman, Karena W. [X-ray Science Division, Argonne National Lab, 9700 S Cass Ave. Argonne IL 60439 USA; Camaioni, Donald M. [Institute for Integrated Catalysis, Pacific Northwest National Lab, P.O. Box 999 Richland WA 99352 USA; Fulton, John L. [Institute for Integrated Catalysis, Pacific Northwest National Lab, P.O. Box 999 Richland WA 99352 USA; Lercher, Johannes A. [Institute for Integrated Catalysis, Pacific Northwest National Lab, P.O. Box 999 Richland WA 99352 USA; Department of Chemistry and Catalysis Research Institute, Technische Universität München, Lichtenbergstrasse 4 85748 Garching Germany; Farha, Omar K. [Department of Chemistry, Northwestern University, 2145 Sheridan Rd. Evanston IL 60208 USA; Hupp, Joseph T. [Materials Science Division, Argonne National Lab, 9700 S Cass Ave. Argonne IL 60439 USA; Department of Chemistry, Northwestern University, 2145 Sheridan Rd. Evanston IL 60208 USA; Martinson, Alex B. F. [Materials Science Division, Argonne National Lab, 9700 S Cass Ave. Argonne IL 60439 USA

    2018-01-02

    Installed on the zirconia nodes of a metal-organic framework (MOF) NU-1000 via targeted vapor-phase synthesis. The catalytic Pt clusters, site-isolated by organic linkers, are shown to exhibit high catalytic activity for ethylene hydrogenation while exhibiting resistance to sintering up to 200 degrees C. In situ IR spectroscopy reveals the presence of both single atoms and few-atom clusters that depend upon synthesis conditions. Operando X-ray absorption spectroscopy and Xray pair distribution analyses reveal unique changes in chemical bonding environment and cluster size stability while on stream. Density functional theory calculations elucidate a favorable reaction pathway for ethylene hydrogenation with the novel catalyst. These results provide evidence that atomic layer deposition (ALD) in MOFs is a versatile approach to the rational synthesis of size-selected clusters, including noble metals, on a high surface area support.

  15. Citric acid induced promoted dispersion of Pt on the support and enhanced catalytic activities for a Pt-based catalyst

    Science.gov (United States)

    Cheng, Tianqiong; Wang, Jianli; Wang, Suning; Cui, Yajuan; Zhang, Hailong; Yan, Shuang; Yuan, Shandong; Chen, Yaoqiang

    2017-12-01

    Citric acid (CA), as the chelating agent, was introduced to obtain the enhanced Pt dispersion and catalytic activities for the Pt-based catalysts supported on oxygen-storage material. The role and content of CA were investigated systematically. It was found that the citric acid-assisted catalysts showed better Pt dispersion and smaller nanoparticle size of Pt. Thus, the catalyst had lower reduction temperature, preferable thermostability and possessed more oxidation state of Pt species under the oxidation atmosphere. The citric acid-induced fresh catalysts were excellent to convert CO and the corresponding aged ones exhibited higher activities for the elimination of all the target pollutants. Among the aged catalysts, P2-a (the mole ratio of Pt/CA is 2:1) presented the best performance. Particularly, compared with the reference sample (Pc-a), the light-off temperatures (T50) of NO, HC and CO for P2-a decreased by 39 °C, 42 °C and 72 °C, respectively, and the full-conversion temperatures (T90) of NO, HC and CO for P2-a decreased by 44 °C, 44 °C and 48 °C, respectively. Therefore, this work provides a facile and valid method to manufacture advanced catalysts for purification of the vehicle exhaust in the future.

  16. Ni–Sn-Supported ZrO2 Catalysts Modified by Indium for Selective CO2 Hydrogenation to Methanol

    KAUST Repository

    Hengne, Amol Mahalingappa

    2018-04-02

    Ni and NiSn supported on zirconia (ZrO2) and on indium (In)-incorporated zirconia (InZrO2) catalysts were prepared by a wet chemical reduction route and tested for hydrogenation of CO2 to methanol in a fixed-bed isothermal flow reactor at 250 °C. The mono-metallic Ni (5%Ni/ZrO2) catalysts showed a very high selectivity for methane (99%) during CO2 hydrogenation. Introduction of Sn to this material with the following formulation 5Ni5Sn/ZrO2 (5% Ni-5% Sn/ZrO2) showed the rate of methanol formation to be 0.0417 μmol/(gcat·s) with 54% selectivity. Furthermore, the combination NiSn supported on InZrO2 (5Ni5Sn/10InZrO2) exhibited a rate of methanol formation 10 times higher than that on 5Ni/ZrO2 (0.1043 μmol/(gcat·s)) with 99% selectivity for methanol. All of these catalysts were characterized by X-ray diffraction, high-resolution transmission electron microscopy (HRTEM), scanning transmission electron microscopy (STEM), X-ray photoelectron spectroscopy, CO2-temperature-programmed desorption, and density functional theory (DFT) studies. Addition of Sn to Ni catalysts resulted in the formation of a NiSn alloy. The NiSn alloy particle size was kept in the range of 10–15 nm, which was evidenced by HRTEM study. DFT analysis was carried out to identify the surface composition as well as the structural location of each element on the surface in three compositions investigated, namely, Ni28Sn27, Ni18Sn37, and Ni37Sn18 bimetallic nanoclusters, and results were in agreement with the STEM and electron energy-loss spectroscopy results. Also, the introduction of “Sn” and “In” helped improve the reducibility of Ni oxide and the basic strength of catalysts. Considerable details of the catalytic and structural properties of the Ni, NiSn, and NiSnIn catalyst systems were elucidated. These observations were decisive for achieving a highly efficient formation rate of methanol via CO2 by the H2 reduction process with high methanol selectivity.

  17. An efficient fabrication of vertically aligned carbon nanotubes on flexible aluminum foils by catalyst-supported chemical vapor deposition

    International Nuclear Information System (INIS)

    Yoshikawa, Naoki; Kishi, Naoki; Sugai, Toshiki; Shinohara, Hisanori; Asari, Takuma; Hayashi, Shigeo

    2008-01-01

    An efficient and versatile growth of thin-layer carbon nanotubes on a flexible aluminum foil (for kitchen use) by catalyst-supported chemical vapor deposition is reported. The aluminum foil used in the present experiment is commercially available for kitchen use. The electron-beam vapor deposition and dip-coating have been used for preparing catalysts on the aluminum foil. Vertically aligned thin-layer CNTs with typical diameters of 2.5-6.0 nm and lengths up to 90 μm are obtained when ethanol is used in combination with Fe and Co catalyst particles at a growth temperature of around 650 deg. C under an Ar/H 2 gas flow. Thermo-gravimetric analyses together with HR-TEM observations indicate that the purity of the CNTs synthesized by the current technique is very high

  18. Polystyrene-supported aluminum chloride as an efficient and reusable catalyst for condensation of indole with various carbonyl compounds

    Directory of Open Access Journals (Sweden)

    BAHMAN TAMAMI

    2010-04-01

    Full Text Available Crosslinked polystyrene-supported aluminum chloride (PS–AlCl3 is a stable, recyclable and environmental friendly heterogeneous catalyst for the condensation of indole with aldehydes and ketones to afford diindolylmethanes. In addition, PS–AlCl3 shows satisfactory selectivity in the reaction of mixtures of an aldehyde and a ketone with indole. Although AlCl3 is water sensitive, corrosive and environmentally harmful compound, PS–AlCl3 is a stable and water-tolerant species. The mild reaction conditions, short reaction times, easy work-up, high to excellent yields, chemoselectivity, reuse of the catalyst for at least ten times without significant change in its catalytic activity, low cost, and easy preparation and handling of the polymeric catalyst are obvious advan-tages of the present method.

  19. Synthesis, characterization and performance of NiMo catalysts supported on titania modified alumina for the hydroprocessing of different gas oils derived from Athabasca bitumen

    Energy Technology Data Exchange (ETDEWEB)

    Ferdous, D.; Bakhshi, N.N.; Dalai, A.K. [Catalysis and Chemical Reactor Engineering Laboratories, Department of Chemical Engineering, University of Saskatchewan, 57 Campus Drive, Saskatoon, Sask. (Canada); Adjaye, J. [Syncrude Canada Ltd., Edmonton Research Center, No. 9421, 17th Avenue, Edmonton, Alta. (Canada)

    2007-03-08

    In this work, a series of NiMo/Al{sub 2}O{sub 3} catalyst was prepared using different Al{sub 2}O{sub 3} supports modified by titania (0-9 wt%). All modified supports and fresh catalysts were characterized by BET surface area, pore volume and pore diameter measurement, TPR, TPD, XRD, FTIR and Raman spectroscopy analyses. The initial activity of these catalysts were tested in a trickle-bed reactor using three different gas oils such as light gas oil (LGO), blended gas oil (blended: 50% LGO and 50% HGO) and heavy gas oil (HGO), all derived from Athabasca bitumen. Little structural change in alumina was observed with the incorporation of titania. XRD analysis showed the well dispersion of Ni and Mo on the support. Titania in alumina increased the formation of polymolybdenum oxide on the catalyst as evident from TPR and Raman analyses. Weak-intermediate-strong acid sites on the catalyst were observed at all titania concentrations. The Lewis and Bronsted acidity on the catalyst surface increased with the increase in titania concentration from 0 to 9 wt%. Nitrogen conversion increased from 57 to 71 wt%, from 83 to 93 wt% and from 75 to 80 wt% for LGO, blended and HGO, respectively and also sulfur conversion of LGO increased from 86 to 92 wt% when titania concentration was increased from 0 to 9 wt%. For blended and HGO, sulfur conversion was in the range 96-99 wt% at all titania concentrations. (author)

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

    International Nuclear Information System (INIS)

    Li Ning; Descorme, Claude; Besson, Michele

    2007-01-01

    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 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 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