WorldWideScience

Sample records for reforming alloy catalysts

  1. Design of a surface alloy catalyst for steam reforming

    DEFF Research Database (Denmark)

    Besenbacher, F.; Chorkendorff, Ib; Clausen, B.S.;

    1998-01-01

    Detailed studies of elementary chemical processes on well-characterized single crystal surfaces have contributed substantially to the understanding of heterogeneous catalysis. insight into the structure of surface alloys combined with an understanding of the relation between the surface composition...... and reactivity is shown to lead directly to new ideas for catalyst design, The feasibility of such an approach is illustrated by the synthesis, characterization, and tests of a high-surface area gold-nickel catalyst for steam reforming....

  2. Development of Sulfur and Carbon Tolerant Reforming Alloy Catalysts Aided Fundamental Atomistic Insights

    Energy Technology Data Exchange (ETDEWEB)

    Suljo Linic

    2008-12-31

    Current hydrocarbon reforming catalysts suffer from rapid carbon and sulfur poisoning. Even though there is a tremendous incentive to develop more efficient catalysts, these materials are currently formulated using inefficient trial and error experimental approaches. We have utilized a hybrid experimental/theoretical approach, combining quantum Density Functional Theory (DFT) calculations and various state-of-the-art experimental tools, to formulate carbon tolerant reforming catalysts. We have employed DFT calculations to develop molecular insights into the elementary chemical transformations that lead to carbon poisoning of Ni catalysts. Based on the obtained molecular insights, we have identified, using DFT quantum calculation, various Ni alloy catalysts as potential carbon tolerant reforming catalysts. The alloy catalysts were synthesized and tested in steam reforming and partial oxidation of methane, propane, and isooctane. We demonstrated that the alloy catalysts are much more carbon-tolerant than monometallic Ni catalysts under nearly stoichiometric steam-to-carbon ratios. Under these conditions, monometallic Ni is rapidly poisoned by sp2 carbon deposits. The research approach is distinguished by two characteristics: (a) knowledge-based, bottomup approach, compared to the traditional trial and error approach, allows for a more efficient and systematic discovery of improved catalysts. (b) the focus is on exploring alloy materials which have been largely unexplored as potential reforming catalysts.

  3. Development of Sulfur and Carbon Tolerant Reforming Alloy Catalysts Aided by Fundamental Atomistics Insights

    Energy Technology Data Exchange (ETDEWEB)

    Suljo Linic

    2006-08-31

    Current hydrocarbon reforming catalysts suffer from rapid carbon and sulfur poisoning. Even though there is a tremendous incentive to develop more efficient catalysts, these materials are currently formulated using inefficient trial and error experimental approaches. We have utilized a novel hybrid experimental/theoretical approach, combining quantum Density Functional Theory (DFT) calculations and various state-of-the-art experimental tools, to formulate carbon tolerant reforming catalysts. We have employed DFT calculations to develop molecular insights into the elementary chemical transformations that lead to carbon poisoning of Ni catalysts. Based on the obtained molecular insights, we have identified, using DFT quantum calculation, Sn/Ni alloy as a potential carbon tolerant reforming catalyst. Sn/Ni alloy was synthesized and tested in steam reforming of methane, propane, and isooctane. We demonstrated that the alloy catalyst is carbon-tolerant under nearly stoichiometric steam-to-carbon ratios. Under these conditions, monometallic Ni is rapidly poisoned by sp2 carbon deposits. The research approach is distinguished by a few characteristics: (a) Knowledge-based, bottom-up approach, compared to the traditional trial and error approach, allows for a more efficient and systematic discovery of improved catalysts. (b) The focus is on exploring alloy materials which have been largely unexplored as potential reforming catalysts.

  4. Magnetically stabilized bed reactor for selective hydrogenation of olefins in reformate with amorphous nickel alloy catalyst

    Institute of Scientific and Technical Information of China (English)

    Xuhong Mu; Enze Min

    2007-01-01

    A magnetically stabilized bed (MSB) reactor for selective hydrogenation of olefins in reformate was developed by combining the advantages of MSB and amorphous nickel alloy catalyst. The effects of operating conditions, such as temperature, pressure, liquid space velocity, hydrogen-to-oil ratio, and magnetic field intensity on the reaction were studied. A mathematical model of MSB reactor for hydrogenation of olefins in reformate was established. A reforming flow scheme with a post-hydrogenation MSB reactor was proposed. Finally, MSB hydrogenation was compared with clay treatment and conventional post-hydrogenation.

  5. Catalyst Alloys Processing

    Science.gov (United States)

    Tan, Xincai

    2014-10-01

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

  6. Alloy catalyst material

    DEFF Research Database (Denmark)

    2014-01-01

    The present invention relates to a novel alloy catalyst material for use in the synthesis of hydrogen peroxide from oxygen and hydrogen, or from oxygen and water. The present invention also relates to a cathode and an electrochemical cell comprising the novel catalyst material, and the process use...

  7. Autothermal reforming catalyst having perovskite structure

    Science.gov (United States)

    Krumpel, Michael; Liu, Di-Jia

    2009-03-24

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

  8. NEW REFORMING CATALYST DEVELOPED BY RIPP

    Institute of Scientific and Technical Information of China (English)

    PUZhong-ying

    2003-01-01

    To meet the demands for high-octane gasoline and aromatics,catalytic reforming process has been advancing quickly in China.The reforming catalysts developed by RIPP have been used in more than 80% capacity of domestic CCR and SR units.This paper introduces the properties of PSVI CCR catalyst developed by RIPP in recent years and also the result from commercial units.The PS-VI catalyst has high activity and good selectivity,under the same reaction conditions,the carbon on catalyst was lowered by 26% in mass as compared with that of the reference catalyst.Among the SR reforming catalysts,the new type of PRT series catalysts have excellent performance at low reaction pressure compared with the ref.Cat A.The aromatics and reformate mass yields of PRT catalyst were 2%-3% and 3%,respectively ,higher than those of Cat A,and the run length was 30%-40% longer as well,which exhibits good prospect of application.

  9. Methane Tri-reforming over nickel catalysts

    OpenAIRE

    García Vargas, José Manuel

    2014-01-01

    The present work is part of a research program carried out in the Department of Chemical Engineering at the University of Castilla-La Mancha, focused in the preparation, characterization and evaluation of catalysts that can be applied in industrially relevant reactions. In this way, the PhD work reported here was aimed to study and improve nickel catalysts applied to the tri-reforming process, evaluating the role of support, precursor and promoter and optimizing the catalyst preparation. Furt...

  10. In silico search for novel methane steam reforming catalysts

    DEFF Research Database (Denmark)

    Xu, Yue; Lausche, Adam C; Wang, Shengguang

    2013-01-01

    This paper demonstrates a method for screening transition metal and metal alloy catalysts based on their predicted rates and stabilities for a given catalytic reaction. This method involves combining reaction and activation energies (available to the public via a web-based application ‘Cat......App’) with a microkinetic modeling technique to predict the rates and selectivities of a prospective material. This paper illustrates this screening technique using the steam reforming of methane to carbon monoxide and hydrogen as a test reaction. While catalysts are already commercially available for this process...

  11. Pyrochlore catalysts for hydrocarbon fuel reforming

    Science.gov (United States)

    Berry, David A.; Shekhawat, Dushyant; Haynes, Daniel; Smith, Mark; Spivey, James J.

    2012-08-14

    A method of catalytically reforming a reactant gas mixture using a pyrochlore catalyst material comprised of one or more pyrochlores having the composition A2B2-y-zB'yB"zO7-.DELTA., where y>0 and z.gtoreq.0. Distribution of catalytically active metals throughout the structure at the B site creates an active and well dispersed metal locked into place in the crystal structure. This greatly reduces the metal sintering that typically occurs on supported catalysts used in reforming reactions, and reduces deactivation by sulfur and carbon. Further, oxygen mobility may also be enhanced by elemental exchange of promoters at sites in the pyrochlore. The pyrochlore catalyst material may be utilized in catalytic reforming reactions for the conversion of hydrocarbon fuels into synthesis gas (H2+CO) for fuel cells, among other uses.

  12. Sintering of nickel steam reforming catalysts

    DEFF Research Database (Denmark)

    Sehested, Jens; Larsen, Niels Wessel; Falsig, Hanne;

    2014-01-01

    . In this paper, particle migration and coalescence in nickel steam reforming catalysts is studied. Density functional theory calculations indicate that Ni-OH dominate nickel transport at nickel surfaces in the presence of steam and hydrogen as Ni-OH has the lowest combined energies of formation and diffusion...... compared to other potential nickel transport species. The relation between experimental catalyst sintering data and the effective mass diffusion constant for Ni-OH is established by numerical modelling of the particle migration and coalescence process. Using this relation, the effective mass diffusion...

  13. Metal catalysts for steam reforming of tar derived from the gasification of lignocellulosic biomass.

    Science.gov (United States)

    Li, Dalin; Tamura, Masazumi; Nakagawa, Yoshinao; Tomishige, Keiichi

    2015-02-01

    Biomass gasification is one of the most important technologies for the conversion of biomass to electricity, fuels, and chemicals. The main obstacle preventing the commercial application of this technology is the presence of tar in the product gas. Catalytic reforming of tar appears a promising approach to remove tar and supported metal catalysts are among the most effective catalysts. Nevertheless, improvement of catalytic performances including activity, stability, resistance to coke deposition and aggregation of metal particles, as well as catalyst regenerability is greatly needed. This review focuses on the design and catalysis of supported metal catalysts for the removal of tar in the gasification of biomass. The recent development of metal catalysts including Rh, Ni, Co, and their alloys for steam reforming of biomass tar and tar model compounds is introduced. The role of metal species, support materials, promoters, and their interfaces is described.

  14. Nickel catalysts for internal reforming in molten carbonate fuel cells

    NARCIS (Netherlands)

    Berger, R.J.; Doesburg, E.B.M.; Ommen, van J.G.; Ross, J.R.H.

    1996-01-01

    Natural gas may be used instead of hydrogen as fuel for the molten carbonate fuel cell (MCFC) by steam reforming the natural gas inside the MCFC, using a nickel catalyst (internal reforming). The severe conditions inside the MCFC, however, require that the catalyst has a very high stability. In orde

  15. Synergetic effects leading to coke-resistant NiCo bimetallic catalysts for dry reforming of methane

    KAUST Repository

    Li, Lidong

    2015-01-08

    A new dry reforming of methane catalyst comprised of NiCo bimetallic nanoparticles and a Mgx(Al)O support that exhibits high coke resistance and long-term on-stream stability is reported. The structural characterization by XRD, TEM, temperature-programmed reduction, and BET analysis demonstrates that the excellent performance of this catalyst is ascribed to the synergy of various parameters, including metal-nanoparticle size, metal-support interaction, catalyst structure, ensemble size, and alloy effects.

  16. Explorative catalyst screening studies on reforming of glycerol in supercritical water

    NARCIS (Netherlands)

    van Bennekom, J. G.; Kirillov, V. A.; Amosov, Y. I.; Krieger, T.; Venderbosch, R. H.; Assink, D.; Lemmens, K. P. J.; Heeres, H. J.

    2012-01-01

    An explorative screening study with Pt/CeZrO2, Ni/ZrO2. Ni/CaO-6Al(2)O(3), NiCu/CeZrO2, and a CuZn alloy was carried out to investigate the influence of different catalysts on the carbon-to-gas efficiency and gas composition in the reforming of glycerol in supercritical water. Experiments were condu

  17. Steam Reforming of Glycerol for Hydrogen Production over Catalyst

    OpenAIRE

    Sadanandam, G.; Sreelatha, N.; Phanikrishna Sharma, M. V.; Kishta Reddy, S.; B. Srinivas; K. Venkateswarlu; T. Krishnudu; Subrahmanyam, M; Durga Kumari, V.

    2012-01-01

    The performance of Ni/SiO2 catalyst for glycerol reforming has been investigated in fixed-bed reactor using careful tailoring of the operational conditions. In this paper, a commercial Engelhard catalyst has been sized and compared to gas product distribution versus catalyst size, water-to-carbon ratio, and stability of the catalyst system. Ni/SiO2 catalysts of three sizes (2×2, 2×4, and 3×5 mm) are evaluated using glycerol: water mixture at 600°C to produce 2 L H2 g−1 cat h−1. The results in...

  18. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-08-15

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

  20. Methane Steam Reforming Kinetics for a Rhodium-Based Catalyst

    DEFF Research Database (Denmark)

    Jakobsen, Jon Geest; Jakobsen, M.; Chorkendorff, Ib

    2010-01-01

    Methane steam reforming is the key reaction to produce synthesis gas and hydrogen at the industrial scale. Here the kinetics of methane steam reforming over a rhodium-based catalyst is investigated in the temperature range 500-800 A degrees C and as a function of CH4, H2O and H-2 partial pressures....... The methane steam reforming reaction cannot be modeled without taking CO and H coverages into account. This is especially important at low temperatures and higher partial pressures of CO and H-2. For methane CO2 reforming experiments, it is also necessary to consider the repulsive interaction of CO...

  1. Routes for deactivation of different autothermal reforming catalysts

    Science.gov (United States)

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

    2016-09-01

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

  2. Pyrochlore-type catalysts for the reforming of hydrocarbon fuels

    Science.gov (United States)

    Berry, David A [Morgantown, WV; Shekhawat, Dushyant [Morgantown, WV; Haynes, Daniel [Morgantown, WV; Smith, Mark [Morgantown, WV; Spivey, James J [Baton Rouge, LA

    2012-03-13

    A method of catalytically reforming a reactant gas mixture using a pyrochlore catalyst material comprised of one or more pyrochlores having the composition A.sub.2-w-xA'.sub.wA''.sub.xB.sub.2-y-zB'.sub.yB''.sub.zO.sub.7-.DELTA.. Distribution of catalytically active metals throughout the structure at the B site creates an active and well dispersed metal locked into place in the crystal structure. This greatly reduces the metal sintering that typically occurs on supported catalysts used in reforming reactions, and reduces deactivation by sulfur and carbon. Further, oxygen mobility may also be enhanced by elemental exchange of promoters at sites in the pyrochlore. The pyrochlore catalyst material may be utilized in catalytic reforming reactions for the conversion of hydrocarbon fuels into synthesis gas (H.sub.2+CO) for fuel cells, among other uses.

  3. Commercial Application of Technique for Removing Sulfates from Reforming Catalyst

    Institute of Scientific and Technical Information of China (English)

    JiChangqing

    2002-01-01

    In the course of reduction of reforming catalyst by not hydrogen a certain amount of chlorine containing compounds is added to the recycle hydrogen to facilitate the reduction of sulfates.The outcome of commercial application of this technique has revealed that the procedure of "regeneration by chlorination→reduction→sulfate removal→sulfiding and oil feed-in"aimed at sulate removal is very simple and can recover the reaction activity of reforming catalyst after having been poisoned by sulfates.This procedure can be disseminated for application in refineries.

  4. Method for improving catalyst function in auto-thermal and partial oxidation reformer-based processors

    Science.gov (United States)

    Ahmed, Shabbir; Papadias, Dionissios D.; Lee, Sheldon H.D.; Ahluwalia, Rajesh K.

    2014-08-26

    The invention provides a method for reforming fuel, the method comprising contacting the fuel to an oxidation catalyst so as to partially oxidize the fuel and generate heat; warming incoming fuel with the heat while simultaneously warming a reforming catalyst with the heat; and reacting the partially oxidized fuel with steam using the reforming catalyst.

  5. Methane Dry Reforming over Alumina Supported Co Catalysts

    Institute of Scientific and Technical Information of China (English)

    CHEN Xiao-wei; XIAO Tian-cun; Sergio L. González Cortés; Malcolm L. H. Green

    2004-01-01

    A series of Co/γ-Al2O3 catalysts were prepared with the impregnation method and characterized by means of the BET specific surface area, X-ray diffraction(XRD), thermogravimetric analysis (TGA) and Laser Raman spectroscopy. The Co/γ-A12O3 catalysts were activated by using H2, 20%CH4/H2 or CH4, respectively. There was no obvious difference between the activities of the Co/γ-Al2O3 catalyst activated by using the different activation methods for methane dry reforming. The catalytic properties of the Co/γ-Al2O3catalysts with different Co loadings were also investigated. The optimized Co loading for the Co/γ-Al2O3 catalyst pretreated with 20% CH4/H2 is around 12% (mass fraction).

  6. Design of Stable Catalysts for Methane-Carbon Dioxide Reforming

    NARCIS (Netherlands)

    Seshan, K.; Bitter, J.H.; Lercher, J.A.

    1998-01-01

    PtZrO2 is an active and stable catalyst for methane- carbon dioxide reforming reaction. The reaction between CO2 and CH4 to yield synthesis gas might proceed vie two different pethways. At high temperatures (>1075K) CO2 can be dissociated on Pt to CO and absorbed oxygen. Methane can be dissociated t

  7. Kinetics of methanol steam reforming over COPZr-2 catalyst

    Institute of Scientific and Technical Information of China (English)

    Yongfeng Li; Weiming Lin; Lin Yu; Zhifeng Hao; Rongjian Mai

    2008-01-01

    The COPZr-2 catalyst, which was prepared in our prophase research, showed good catalytic performance in methanol steam reforming reaction. In this article, the best one was chosen as an example to study the reaction kinetics of methanol steam reforming over this type of catalyst. First, the effects of methanol conversion to outlet CO2 and methanol conversion to outlet CO on methanol pseudo contact time W/FMeOH were investigated. Then by applying the reaction route that methanol direct reforming (DR) and methanol decomposition (DE) were carried out in parallel, the reaction kinetic model with power function type was established. And the parameters for the model were estimated using a non-linear regression program which computed weighted least squares of the defined objects function. Finally, the kinetic model passed the correlation test and the F-test.

  8. Influence of Steam Reforming Catalyst Geometry on the Performance of Tubular Reformer – Simulation Calculations

    Directory of Open Access Journals (Sweden)

    Franczyk Ewelina

    2015-06-01

    Full Text Available A proper selection of steam reforming catalyst geometry has a direct effect on the efficiency and economy of hydrogen production from natural gas and is a very important technological and engineering issue in terms of process optimisation. This paper determines the influence of widely used seven-hole grain diameter (ranging from 11 to 21 mm, h/d (height/diameter ratio of catalyst grain and Sh/St (hole surface/total cylinder surface in cross-section ratio (ranging from 0.13 to 0.37 on the gas load of catalyst bed, gas flow resistance, maximum wall temperature and the risk of catalyst coking. Calculations were based on the one-dimensional pseudo-homogeneous model of a steam reforming tubular reactor, with catalyst parameters derived from our investigations. The process analysis shows that it is advantageous, along the whole reformer tube length, to apply catalyst forms of h/d = 1 ratio, relatively large dimensions, possibly high bed porosity and Sh/St ≈ 0.30-0.37 ratio. It enables a considerable process intensification and the processing of more natural gas at the same flow resistance, despite lower bed activity, without catalyst coking risk. Alternatively, plant pressure drop can be reduced maintaining the same gas load, which translates directly into diminishing the operating costs as a result of lowering power consumption for gas compression.

  9. Production of syngas by ethanol reforming on Ni catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Catapan, Rafael C.; Oliveira, Amir A.M.; Donadel, Karina; Oliveira, Antonio Pedro N.; Rambo, Carlos R. [Federal University of Santa Catarina (UFSC), Florianopolis, SC (Brazil). Dept. of Mechanical Engineering. Lab. of Combustion and Thermal Systems Engineering], Emails: catapan@labcet.ufsc.br, donadel@emc.ufsc.br, pedronovaes@emc.ufsc.br, rambo@enq.ufsc.br; Oliveira, Therezinha Maria N.; Wagner, Theodoro M. [Universidade da Regiao de Joinville, SC (Brazil). Campus Universitario Bom Retiro], E-mails: tnovais@univille.br, theowag@terra.com.br

    2010-07-01

    In the recent literature, attention has been directed to the development of noble metals based catalysts for the ethanol reforming. However, the high costs and low availability of noble metals, e.g. platinum, as a resource justify the development of alternatives technologically, economically and environmentally viable such as Ni-based catalysts. Here, the thermal decomposition, partial oxidation and steam reforming of ethanol over SiO{sub 2} supported Ni was studied in a packed bed reactor in the 673 - 973 K temperature range at 1 atm. The catalyst was produced from 10% NiO, 5% of bentonite and 85% (wt.) of natural amorphous silica fibers (NASF). Scanning Electron Microscopy (SEM) evaluation revealed that particles of Ni were homogeneously distributed over the NASF. The X-ray diffraction (XRD) patterns did not show peaks related to silicates in all spectra, which indicates that there is no, apparently, interaction between the nickel catalysts and SiO{sub 2} or devitrification The reactions of ethanol on this catalyst occurs mainly by the dehydrogenation reaction generating acetaldehyde. Further, CH{sub 3}CHO is decomposed to CH{sub 4} and CO. In parallel to this route, ethanol is dehydrated producing ethylene, which is successively dehydrogenated in Ni sites generating carbon on the surface. Also, carbon can be produced by consecutive dehydrogenation of CH{sub 4}. Both reactions contribute to increase the production of H{sub 2} to values higher than those predicted by the thermodynamic equilibrium. (author)

  10. Sulfur Tolerance of Carbide Catalysts Under Hydrocarbon Reforming Conditions

    Science.gov (United States)

    2007-11-02

    with a low surface area bulk catalyst produce similar activities. In addition it was also found that incomplete carburization during TPR synthesis...reduces the oxycarbide to Mo, which is easily carburized under reforming conditions. Pretreatment at 600 oC, was largely ineffective and it is...at atmospheric pressure [3]. They attributed this to competitive kinetics between oxidation and carburization , concluding that carburization

  11. Modified Ni-Cu catalysts for ethanol steam reforming

    Science.gov (United States)

    Dan, M.; Mihet, M.; Almasan, V.; Borodi, G.; Katona, G.; Muresan, L.; Lazar, M. D.

    2013-11-01

    Three Ni-Cu catalysts, having different Cu content, supported on γ-alumina were synthesized by wet co-impregnation method, characterized and tested in the ethanol steam reforming (ESR) reaction. The catalysts were characterized for determination of: total surface area and porosity (N2 adsorption - desorption using BET and Dollimer Heal methods), Ni surface area (hydrogen chemisorption), crystallinity and Ni crystallites size (X-Ray Diffraction), type of catalytic active centers (Hydrogen Temperature Programmed Reduction). Total surface area and Ni crystallites size are not significantly influenced by the addition of Cu, while Ni surface area is drastically diminished by increasing of Cu concentration. Steam reforming experiments were performed at atmospheric pressure, temperature range 150-350°C, and ethanol - water molar ration of 1 at 30, using Ar as carrier gas. Ethanol conversion and hydrogen production increase by the addition of Cu. At 350°C there is a direct connection between hydrogen production and Cu concentration. Catalysts deactivation in 24h time on stream was studied by Transmission Electron Microscopy (TEM) and temperature-programmed reduction (TPR) on used catalysts. Coke deposition was observed at all studied temperatures; at 150°C amorphous carbon was evidenced, while at 350°C crystalline, filamentous carbon is formed.

  12. Electrodeposited NiCu Alloy Catalysts for Glucose Oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Jieun; Park, Hansoo; Kim, Sookil [Chung-Ang Univ., Seoul (Korea, Republic of); Ahn, Sang Hyun; Jang, Jong Hyun [Korea Institute of Science and Technology, Seoul (Korea, Republic of)

    2014-07-15

    NiCu alloys have been suggested as potential candidates for catalysts in glucose oxidation. In this study, NiCu alloys with different compositions were prepared on a glassy carbon substrate by changing the electrodeposition potential to examine the effect of Ni/Cu ratios in alloys on catalytic activity toward glucose oxidation. Cyclic voltammetry and chronoamperometry showed that NiCu alloys had higher catalytic activity than pure Ni and Cu catalysts. Especially, Ni{sub 59}Cu{sub 41} had superior catalytic activity, which was about twice that of Ni at a given oxidation potential. X-ray analyses showed that the oxidation state of Ni in NiCu alloys was increased with the content of Cu by lattice expansion. Ni components in alloys with higher oxidation state were more effective in the oxidation of glucose.

  13. Controlled surface segregation leads to efficient coke-resistant nickel/platinum bimetallic catalysts for the dry reforming of methane

    KAUST Repository

    Li, Lidong

    2015-02-03

    Surface composition and structure are of vital importance for heterogeneous catalysts, especially for bimetallic catalysts, which often vary as a function of reaction conditions (known as surface segregation). The preparation of bimetallic catalysts with controlled metal surface composition and structure is very challenging. In this study, we synthesize a series of Ni/Pt bimetallic catalysts with controlled metal surface composition and structure using a method derived from surface organometallic chemistry. The evolution of the surface composition and structure of the obtained bimetallic catalysts under simulated reaction conditions is investigated by various techniques, which include CO-probe IR spectroscopy, high-angle annular dark-field scanning transmission electron microscopy, energy-dispersive X-ray spectroscopy, extended X-ray absorption fine structure analysis, X-ray absorption near-edge structure analysis, XRD, and X-ray photoelectron spectroscopy. It is demonstrated that the structure of the bimetallic catalyst is evolved from Pt monolayer island-modified Ni nanoparticles to core-shell bimetallic nanoparticles composed of a Ni-rich core and a Ni/Pt alloy shell upon thermal treatment. These catalysts are active for the dry reforming of methane, and their catalytic activities, stabilities, and carbon formation vary with their surface composition and structure. The reform of reforming: A series of alumina-supported Ni/Pt bimetallic nanoparticles (NPs) with controlled surface composition and structure are prepared. Remarkable surface segregation for these bimetallic NPs is observed upon thermal treatment. These bimetallic NPs are active catalysts for CO2 reforming of CH4, and their catalytic activities, stabilities, and carbon formation vary with their surface composition and structure.

  14. RIPP开发的催化重整技术%NEW REFORMING CATALYST DEVELOPED BY RIPP

    Institute of Scientific and Technical Information of China (English)

    濮仲英

    2003-01-01

    To meet the demands for high-octane gasoline and aromatics, catalytic reforming process has been advancing quickly in China. The reforming catalysts developed by RIPP have been used in more than 80% capacity of domestic CCR and SR units. This paper introduces the properties of PS-VI CCR catalyst developed by RIPP in recent years and also the result from commercial units. The PS-VI catalyst has high activity and good selectivity, under the same reaction conditions, the carbon on catalyst was lowered by 26% in mass as compared with that of the reference catalyst. Among the SR reforming catalysts, the new type of PRT series catalysts have excellent performance at low reaction pressure compared with the ref. Cat A. The aromatics and reformate mass yields of PRT catalyst were 2%~3% and 3%, respectively, higher than those of Cat A, and the run length was 30%~40% longer as well, which exhibits good prospect of application.

  15. Cooperativity and Dynamics Increase the Performance of NiFe Dry Reforming Catalysts.

    Science.gov (United States)

    Kim, Sung Min; Abdala, Paula Macarena; Margossian, Tigran; Hosseini, Davood; Foppa, Lucas; Armutlulu, Andac; van Beek, Wouter; Comas-Vives, Aleix; Copéret, Christophe; Müller, Christoph

    2017-02-08

    The dry reforming of methane (DRM), i.e., the reaction of methane and CO2 to form a synthesis gas, converts two major greenhouse gases into a useful chemical feedstock. In this work, we probe the effect and role of Fe in bimetallic NiFe dry reforming catalysts. To this end, monometallic Ni, Fe, and bimetallic Ni-Fe catalysts supported on a MgxAlyOz matrix derived via a hydrotalcite-like precursor were synthesized. Importantly, the textural features of the catalysts, i.e., the specific surface area (172-178 m(2)/gcat), pore volume (0.51-0.66 cm(3)/gcat), and particle size (5.4-5.8 nm) were kept constant. Bimetallic, Ni4Fe1 with Ni/(Ni + Fe) = 0.8, showed the highest activity and stability, whereas rapid deactivation and a low catalytic activity were observed for monometallic Ni and Fe catalysts, respectively. XRD, Raman, TPO, and TEM analysis confirmed that the deactivation of monometallic Ni catalysts was in large due to the formation of graphitic carbon. The promoting effect of Fe in bimetallic Ni-Fe was elucidated by combining operando XRD and XAS analyses and energy-dispersive X-ray spectroscopy complemented with density functional theory calculations. Under dry reforming conditions, Fe is oxidized partially to FeO leading to a partial dealloying and formation of a Ni-richer NiFe alloy. Fe migrates leading to the formation of FeO preferentially at the surface. Experiments in an inert helium atmosphere confirm that FeO reacts via a redox mechanism with carbon deposits forming CO, whereby the reduced Fe restores the original Ni-Fe alloy. Owing to the high activity of the material and the absence of any XRD signature of FeO, it is very likely that FeO is formed as small domains of a few atom layer thickness covering a fraction of the surface of the Ni-rich particles, ensuring a close proximity of the carbon removal (FeO) and methane activation (Ni) sites.

  16. Kinetic behaviour of commercial catalysts for methane reforming in ethanol steam reforming process

    Institute of Scientific and Technical Information of China (English)

    Jorge Vicente; Javier Ere˜na; Martin Olazar; Pedro L. Benito; Javier Bilbao; Ana G. Gayubo

    2014-01-01

    Ethanol steam reforming has been studied in a fluidized bed (in order to ensure bed isothermicity) on commercial catalysts for methane reforming. The results allow analyzing the effect of temperature (in 300-700◦C range), and both metal and support nature on the reaction indices (ethanol conversion, yields and selectivities to H2 and byproducts (CO2, CO, CH4 and C2H4O)). Special attention has been paid to catalysts’ stability by comparing the evolution of the reaction indices with time on stream at 500◦C (minimum CO formation) and 700◦C (minimum deactivation by coke deposition). Although they provide a slightly lower H2 yield, the results evidence a good behaviour of Ni based catalysts, indicating that they are an interesting alternative of more expensive Rh based ones.

  17. Promotion Effects of Nickel Catalysts of Dry Reforming with Methane

    Institute of Scientific and Technical Information of China (English)

    YAN,Zi-Feng(阎子峰); DING,Rong-Gang(丁荣刚); LIU,Xin-Mei(刘欣梅); SONG,Lin-Hua(宋林花)

    2001-01-01

    The promotion effects of nickel catalyst of dry reforming with methane were extensively investigated by means of XRD,SEM, EDX, N2-adsorption and H2-adsorption. XRD characterization indicated that good dispersion of nickel oxide and MgO promoter is achieved over γ-Al2O3 support. Addition of MgO promoter effectively retards the formation of NiS12O4 phase. SEM and EDX analysis exhibited that the addition ofrare-earth metal oxide CeO2 effectively promotes the Ni metal dispersion on the surface of the catalysts despite of undesirable self-dispersion of CeO2 promoter. Furthermore, the nickel component is gradually dispersed on the surface of the support following the exposure to reaction gas mixture for a period of time. The addition of MgO inhibited the self-dispersion and promotion effect of CeO2 on Ni dispersion on the catalysts. H2 chemisorption revealed that the addition of the alkaline oxide MgO promoter significantly prohibits the metal dispersion on the catalyst. Inappropriate promoter addition can result in sharp decrease of the metal dispersion. N2-adsorption indicated that oxide promoter was mostly concentrated on the outer layer of the alumina support while the nickel metal was generally dispersed in the support pores. Addition of promoters contributed to more reduction in mesopore volume.

  18. On the role of reactant transport and (surface) alloy formation for the CO tolerance of carbon supported PtRu polymer electrolyte fuel cell catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Kaiser, J.; Colmenares, L.; Jusys, Z.; Behm, R.J. [Abt. Oberflaechenchemie und Katalyse, Universitaet Ulm (Germany); Moertel, R.; Boennemann, H. [Max-Planck-Institut fuer Kohlenforschung, Muelheim a.d. Ruhr (Germany); Koehl, G.; Modrow, H.; Hormes, J. [Physikalisches Institut, Universitaet Bonn (Germany)

    2006-07-15

    The role of atomic scale intermixing for the electrocatalytic activity of bimetallic PtRu anode catalysts in reformate operated polymer electrolyte fuel cells (PEFC) was investigated, exploiting the specific properties of colloid based catalyst synthesis for the selective preparation of alloyed and non-alloyed bimetallic catalysts. Three different carbon supported PtRu catalysts with different degrees of Pt and Ru intermixing, consisting of (i) carbon supported PtRu alloy particles (PtRu/C), (ii) Pt and Ru particles co-deposited on the same carbon support (Pt+Ru/C), and (iii) a mixture of carbon supported Pt and carbon supported Ru (Pt/C+Ru/C) as well as the respective monometallic Pt/C and Ru/C catalysts were prepared and characterized by electron microscopy (TEM), X-ray absorption spectroscopy, and CO stripping. Their performance as PEFC anode catalysts was evaluated by oxidation of a H{sub 2}/2%CO gas mixture (simulated reformate) under fuel cell relevant conditions (elevated temperature, continuous reaction and controlled reactant transport) in a rotating disk electrode (RDE) set-up. The CO tolerance and H{sub 2} oxidation activity of the three catalysts is comparable and distinctly different from that of the monometallic catalysts. The results indicate significant transport of the reactants, CO{sub ad} and/or OH{sub ad}, between Pt and Ru surface areas and particles for all three catalysts, with only subtle differences from the alloy catalyst to the physical mixture. The high activity and CO tolerance of the bimetallic catalysts, through the formation of bimetallic surfaces, is explained, e.g., by contact formation in nanoparticle agglomerates or by material transport and subsequent surface decoration/surface alloy formation during catalyst preparation, conditioning, and operation. The instability and mobility of the catalysts under these conditions closely resembles concepts in gas phase catalysis. (Abstract Copyright [2006], Wiley Periodicals, Inc.)

  19. Catalytic reforming of glycerol in supercritical water over bimetallic Pt-Ni catalyst

    NARCIS (Netherlands)

    Chakinala, Anand G.; Swaaij, van Wim P.M.; Kersten, Sascha R.A.; Vlieger, de Dennis; Seshan, Kulathuiyer; Brilman, D.W.F. (Wim)

    2013-01-01

    Catalytic reforming of pure glycerol for the production of hydrogen at low temperature and short residence times in supercritical water was investigated using a bimetallic Pt–Ni catalyst supported on alumina. Initial tests were carried out to study the reforming activity of bimetallic Pt–Ni catalyst

  20. Development of a Catalyst/Sorbent for Methane Reforming

    Energy Technology Data Exchange (ETDEWEB)

    B.H. Shans; T.D. Wheelock; Justinus Satrio; Karl Albrecht; Tanya Harris Janine Keeley; Ben Silva; Aaron Shell; Molly Lohry; Zachary Beversdorf

    2008-12-31

    This project led to the further development of a combined catalyst and sorbent for improving the process technology required for converting CH{sub 4} and/or CO into H{sub 2} while simultaneously separating the CO{sub 2} byproduct all in a single step. The new material is in the form of core-in-shell pellets such that each pellet consists of a CaO core surrounded by an alumina-based shell capable of supporting a Ni catalyst. The Ni is capable of catalyzing the reactions of steam with CH{sub 4} or CO to produce H{sub 2} and CO{sub 2}, whereas the CaO is capable of absorbing the CO{sub 2} as it is produced. The absorption of CO{sub 2} eliminates the reaction inhibiting effects of CO{sub 2} and provides a means for recovering the CO{sub 2} in a useful form. The present work showed that the lifecycle performance of the sorbent can be improved either by incorporating a specific amount of MgO in the material or by calcining CaO derived from limestone at 1100 C for an extended period. It also showed how to prepare a strong shell material with a large surface area required for supporting an active Ni catalyst. The method combines graded particles of {alpha}-alumina with noncrystalline alumina having a large specific surface area together with a strength promoting additive followed by controlled calcination. Two different additives produced good results: 3 {micro}m limestone and lanthanum nitrate which were converted to their respective oxides upon calcination. The oxides partially reacted with the alumina to form aluminates which probably accounted for the strength enhancing properties of the additives. The use of lanthanum made it possible to calcine the shell material at a lower temperature, which was less detrimental to the surface area, but still capable of producing a strong shell. Core-in-shell pellets made with the improved shell materials and impregnated with a Ni catalyst were used for steam reforming CH{sub 4} at different temperatures and pressures. Under all

  1. Heat transfer effects on the methanol-steam reforming with partially filled catalyst layers

    Energy Technology Data Exchange (ETDEWEB)

    Chein, Rei-Yu.; Chen, Li-Chang [Department of Mechanical Engineering, National Chung-Hsing University, Taichung City, Taiwan 402 (China); Chen, Yen-Cho [Department of Energy and Resources, National United University, Miaoli City, Taiwan 360 (China); Chung, J.N. [Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, FL 32611-6300 (United States)

    2009-07-15

    The heat transfer effects on a methanol-steam reforming (MSR) process are numerically investigated using a circular reformer with a partially (referred to as the wall-coated reformer) or entirely filled catalyst layer (referred to as the packed-bed reformer). The catalyst layer is formed by packing CuO/ZnO/Al{sub 2}O{sub 3} catalyst particles with a certain porosity and permeability. The fluid flow characteristics are strongly affected by the catalyst-layer thickness. As a consequence, the heat and mass transfer also depend on the catalyst-layer thickness. Under heat supplied by wall heat flux conditions, it is found that higher reforming temperature can be obtained for the wall-coated reformer compared with the packed-bed reformer. This results in the wall-coated reformer having a better methanol conversion efficiency compared with the packed-bed reformer. Based on our study, the minimum heat transfer coefficient, maximum methanol conversion and maximum carbon monoxide production are obtained when the catalyst-layer thickness is 90% of the reformer radius. (author)

  2. "Intelligent" reforming catalysts: Trace noble metal-doped Ni/Mg(Al)O derived from hydrotalcites

    Institute of Scientific and Technical Information of China (English)

    Katsuomi Takehira

    2009-01-01

    Trace amounts of noble metal-doped Ni/Mg(Al)O catalysts were pre-pared starting from Mg-Al hydrotalcites (HTs) and tested in daily start-up and shut-down (DSS) operation of steam reforming (SR) of methane or partial oxidation (PO) of propane. Although Ni/Mg(Al)O catalysts prepared from Mg(Ni)-Al HT exhibited high and stable activity in stationary SR,PO and dry reforming of methane and propane,the Ni/Mg(Al)O catalysts were drastically deactivated due to Ni oxidation by steam as purge gas when they were applied in DSS SR of methane. Such deactivation was effectively suppressed by dop-ing trace amounts of noble metal on the catalysts by using a "memory effect" of HTs. Moreover,the noble metal-doped Ni/Mg(Al)O cat-alysts exhibited "intelligent" catalytic behaviors,i.e.,self-activation and self-regenerative activity,leading to high and sustainable activity during DSS operation. Pt was the most effective among noble met-als tested. The self-activation occurred by the reduction of Ni2+ in Mg(Ni,Al)O periclase to Ni~0 assisted by hydrogen spillover from Pt (or Pt-Ni alloy). The self-regenerative activity was accomplished by self-redispersion of active Ni~0 particles due to a reversible reduction-oxidation movement of Ni between the outside and the inside of the Mg(Al)O periclase crystal;surface Ni~0 was oxidized to Ni~(2+) by steam and incorporated into Mg(Ni~(2+),Al)O periclase,whereas the Ni~(2+) in the periclase was reduced to Ni~0 by the hydrogen spillover and appeared as the fine Ni~0 particles on the catalyst surface. Fur-ther a "green" preparation of the Pt/Ni/[Mg3.5Al]O catalysts was ac-complished starting from commercial Mg3.5-Al HT by calcination,followed by sequential impregnation of Ni and Pt.

  3. Autothermal and partial oxidation reformer-based fuel processor, method for improving catalyst function in autothermal and partial oxidation reformer-based processors

    Science.gov (United States)

    Ahmed, Shabbir; Papadias, Dionissios D.; Lee, Sheldon H. D.; Ahluwalia, Rajesh K.

    2013-01-08

    The invention provides a fuel processor comprising a linear flow structure having an upstream portion and a downstream portion; a first catalyst supported at the upstream portion; and a second catalyst supported at the downstream portion, wherein the first catalyst is in fluid communication with the second catalyst. Also provided is a method for reforming fuel, the method comprising contacting the fuel to an oxidation catalyst so as to partially oxidize the fuel and generate heat; warming incoming fuel with the heat while simultaneously warming a reforming catalyst with the heat; and reacting the partially oxidized fuel with steam using the reforming catalyst.

  4. Glycerol Steam Reforming Over Ni-Fe-Ce/Al2O3 Catalyst: Effect of Cerium.

    Science.gov (United States)

    Go, Gwang-Sub; Go, Yoo-Jin; Lee, Hong-Joo; Moon, Dong-Ju; Park, Nam-Cook; Kim, Young-Chul

    2016-02-01

    In this work, hydrogen production from glycerol by steam reforming was studied using Ni-metal oxide catalysts. Ni-based catalyst becomes deactivated during steam reforming reactions because of coke deposits and sintering. Therefore, the aim of this study was to reduce carbon deposits and sintering on the catalyst surface by adding a promoter. Ni-metal oxide catalysts supported on Al2O3 were prepared via impregnation method, and the calcined catalyst was reduced under H2 flow for 2 h prior to the reaction. The characteristics of the catalysts were examined by XRD, TPR, TGA, and SEM. The Ni-Fe-Ce/Al2O3 catalyst, which contained less than 2 wt% Ce, showed the highest hydrogen selectivity and glycerol conversion. Further analysis of the catalysts revealed that the Ni-Fe-Ce/Al2O3 catalyst required a lower reduction temperature and produced minimum carbon deposit.

  5. Woody biomass and RPF gasification using reforming catalyst and calcium oxide.

    Science.gov (United States)

    Kobayashi, Jun; Kawamoto, Katsuya; Fukushima, Ryutaro; Tanaka, Shingo

    2011-05-01

    This study focused on steam gasification and reforming of waste biomass using a reforming catalyst. The purpose of the study was to evaluate the durability of a commercial Ni reforming catalyst and the effect of CaO on the reforming behavior, and to clarify detailed factors of catalytic performance, as well as the effect of operating parameters on the characteristics of produced gas composition. Moreover, catalyst regeneration was carried out and the behavior of catalytic activity based on gas composition was investigated. Using a fluidized bed gasifier and a fixed bed reformer, gasification and reforming of waste biomass were carried out. Commercial Ni-based catalyst and calcined limestone (CaO) were applied to the reforming reaction. Temperature of the gasifier and reformer was almost 1023K. Ratio of steam to carbon in the feedstock [molmol(-1)] and equivalence ratio (i.e., ratio of actual to theoretical amount of oxygen) [-] were set at about 2 and 0.3, respectively. The feed rate of the feedstock into the bench-scale gasifier was almost 15kgh(-1). The results of waste biomass gasification confirmed the improvement in H(2) composition by the CO(2) absorption reaction using the reforming catalyst and CaO. In addition, CaO proved to be especially effective in decreasing the tar concentration in the case of woody biomass gasification. Catalytic activity was maintained by means of catalyst regeneration processing by hydrogen reduction after air oxidation when woody biomass was used as feedstock.

  6. Controlled Surface Segregation Leads to Efficient Coke-Resistant Nickel/Platinum Bimetallic Catalysts for the Dry Reforming of Methane

    Energy Technology Data Exchange (ETDEWEB)

    Li, Lidong [King Abdullah Univ. of Science and Technology, Thuwal (Saudi Arabia); Zhou, Lu [King Abdullah Univ. of Science and Technology, Thuwal (Saudi Arabia); Ould-Chikh, Samy [King Abdullah Univ. of Science and Technology, Thuwal (Saudi Arabia); Anjum, Dalaver H. [King Abdullah Univ. of Science and Technology, Thuwal (Saudi Arabia); Kanoun, Mohammed B. [King Abdullah Univ. of Science and Technology, Thuwal (Saudi Arabia); Scaranto, Jessica [SABIC Corporate Research and Innovation Center, Thuwal (Saudi Arabia); Hedhili, Mohamed N. [King Abdullah Univ. of Science and Technology, Thuwal (Saudi Arabia); Khalid, Syed [Brookhaven National Lab. (BNL), Upton, NY (United States); Laveille, Paco V. [King Abdullah Univ. of Science and Technology, Thuwal (Saudi Arabia); D' Souza, Lawrence [SABIC Corporate Research and Innovation Center, Thuwal (Saudi Arabia); Clo, Alain [King Abdullah Univ. of Science and Technology, Thuwal (Saudi Arabia); Basset, Jean-Marie [King Abdullah Univ. of Science and Technology, Thuwal (Saudi Arabia)

    2015-02-03

    The surface composition and structure are of vital importance for heterogeneous catalysts, especially for bimetallic catalysts, which often vary as a function of reaction conditions (known as surface segregation). The preparation of bimetallic catalysts with controlled metal surface composition and structure is very challenging. In this study, we synthesize a series of Ni/Pt bimetallic catalysts with controlled metal surface composition and structure using a method derived from surface organometallic chemistry. Moreover, the evolution of the surface composition and structure of the obtained bimetallic catalysts under simulated reaction conditions is investigated by various techniques, which include CO-probe IR spectroscopy, high-angle annular dark-field scanning transmission electron microscopy, energy-dispersive X-ray spectroscopy, extended X-ray absorption fine structure analysis, X-ray absorption near-edge structure analysis, XRD, and X-ray photoelectron spectroscopy. It is demonstrated that the structure of the bimetallic catalyst is evolved from Pt monolayer island-modified Ni nanoparticles to core–shell bimetallic nanoparticles composed of a Ni-rich core and a Ni/Pt alloy shell upon thermal treatment. The catalysts are active for the dry reforming of methane, and their catalytic activities, stabilities, and carbon formation vary with their surface composition and structure.

  7. An in-depth understanding of the bimetallic effects and coked carbon species on an active bimetallic Ni(Co)/Al2O3 dry reforming catalyst.

    Science.gov (United States)

    Liao, Xin; Gerdts, Rihards; Parker, Stewart F; Chi, Lina; Zhao, Yongxiang; Hill, Martyn; Guo, Junqiu; Jones, Martin O; Jiang, Zheng

    2016-06-29

    Ni/Al2O3, Co/Al2O3 and bimetallic Ni(Co)/Al2O3 catalysts were prepared using an impregnation method and employed in CO2 dry reforming of methane under coking-favored conditions. The spent catalysts were carefully characterized using typical characterization technologies and inelastic neutron scattering spectroscopy. The bimetallic catalyst exhibited a superior activity and anti-coking performance compared to Ni/Al2O3, while the most resistant to coking behavior was Co/Al2O3. The enhanced activity of the Ni(Co)/Al2O3 bimetallic catalyst is attributed to the reduced particle size of metallic species and resistance to forming stable filamentous carbon. The overall carbon deposition on the spent bimetallic catalyst is comparable to that of the spent Ni/Al2O3 catalyst, whereas the carbon deposited on the bimetallic catalyst is mainly less-stable carbonaceous species as confirmed by SEM, TPO, Raman and INS characterization. This study provides an in depth understanding of alloy effects in catalysts, the chemical nature of coked carbon on spent Ni-based catalysts and, hopefully, inspires the creative design of a new bimetallic catalyst for dry reforming reactions.

  8. Furfural Hydrogenation on Alloyed Copper Catalysts With Additives of Ferrosilicium

    Directory of Open Access Journals (Sweden)

    T. K. Akilov

    2015-12-01

    Full Text Available The present work is dedicated to the study of influence of ferrosilicium additives [FA*-ferroalloy containing (% mass: 46.8 Si, ~53,0 Fe, other are (C, P, S impurities] on the activity of alloyed Gu-Al = 50-50 catalyst in the reaction of furfural hydrogenation under hydrogen pressure. Components content varied (% mass: Cu- 40...49, aluminum- 50, FA* -1.0...10.0. The catalysts were prepared from 1g alloys by leaching it with 20% of aqueous solution of caustic soda in boiling water-bath during 1 hour. The phase composition and structure of alloys were investigated by means of roentgenographic and X-ray spectrum methods.

  9. 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.

  10. Analysis alloy quasicrystalline Al62,2 Cu25,3 Fe12,5 for steam reforming of methanol

    Directory of Open Access Journals (Sweden)

    Lourdes Cristina Lucena Agostinho Jamshidi

    2015-10-01

    Full Text Available This study shows a good performance of quasicrystal Al62,2Cu25,3Fe12,5 as catalyst in catalytic reactions. This metal catalyst, without being leached with acid or base, with dry stoichiometric composition, Al62,2Cu25,3Fe12,5 is revealed among the reactions which occurred to be a partial oxidation; and promoted the formation of products: methanol, methanal + methanoic acid, water and dimethyl ether. For this research were used such experimental techniques as X-ray Diffraction (XRD to follow the evolution of the alloy phase, the Scanning Electron Microscopy (SEM that provides the study of surface microstructure, and Transmission Electron Microscopy (MET. All these techniques study the morphology of the internal phase, and defect a quasicrystalline nucleus. Catalytic tests of methanol conversion and selectivity intermediate products were obtained using this catalyst quasicrystal. The activity and stability of quasicrystal catalyst for reforming of methanol vapor show sufficient growth compared to the other catalysts. Fe and Cu species are highly dispersed in the homogeneous layer of quasicrystal catalyst which increase the catalytic activity and suppress the aggregation of Cu particles. We suppose that the quasicrystal can be a good catalyst used in a catalytic steam reforming, with high catalytic activity and excellent thermal stability.

  11. Autothermal reforming over a Pt/Gd-doped ceria catalyst: Heat and mass transport limitations in the steam reforming section

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Sungkwang [Center for Fuel Cell Research, Korea Institute of Science and Technology, 39-1 Hawolgok-dong, Sungbuk-gu, Seoul 136-791 (Korea); Bae, Joongmyeon [Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, 373-1 Guseong-Dong, Yuseong-Gu, Daejeon 305-701 (Korea)

    2010-07-15

    Autothermal reforming (ATR) has several advantages for fuel cell applications, such as a compact reactor structure and fast response. Using oxidation reactions inside the reactor, ATR does not have the external heat transfer limitations associated with steam reforming. However, mass and heat transfer limitations inside and outside the catalyst particles are still anticipated. In this study, transport limitations in the steam reforming section of ATR over a Pt/Gd-doped ceria catalyst are analyzed by numerical simulations based on a reaction rate equation in which parameters are adjusted to measured kinetic data. The simulation results show that significant transport limitations characterize the steam reforming section of packed-bed ATR reactors. The activity per catalyst bed volume is highly dependent on the particle size, and only the thin exterior layer of the particles is involved in catalyzing the reactions. Based on the results, it is shown that an eggshell type catalyst particle could reduce catalyst material significantly without a considerable decline in the activity per catalyst bed volume. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    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.

  13. Optimization of pyrochlore catalysts for the dry reforming of methane

    Science.gov (United States)

    Polo Garzon, Felipe

    The conversion of methane into syngas (a mixture of CO and H2), which can be further converted into a variety of chemicals and particularly liquid fuels, is of growing importance given recent increases in methane production world-wide. Furthermore, since using CO2 as the co-feed offers many environmental advantages, dry reforming of methane (DRM, CH4 + CO2 [special character omitted] 2CO + 2H 2) has received renewed attention. In recent years, experimentalists have shown that the Rh-substituted lanthanum zirconate pyrochlore (LRhZ) material is catalytically active for DRM, exhibits long-term thermal stability and resists deactivation; however, previous to this doctoral work, a detailed understanding of the reaction mechanism on pyrochlore catalyst surfaces was still scarce, making it difficult to optimize this material. In this work, initial computational efforts employing density functional theory (DFT) showed the plane (111) of the LRhZ crystal structure as the one catalytically active for DRM. In addition, the primary reaction pathway was identified, along with two rate determining steps (RDSs), the CH2 oxygenation step and the CHO dehydrogenation step, which lie on the CH 4 dehydrogenation/oxygenation path. The mechanistic understanding of DRM over LRhZ was further developed using steady-state isotopic transient kinetic analysis (SSITKA). Reversible adsorption of CO2 on the surface was observed, along with short surface residence times (temperature. Comparisons between isotopic responses supported the DFT-derived reaction mechanism. Furthermore, isotopic transient kinetics confirmed that all metal atoms (Rh, Zr and La) on the surface are involved in the reaction mechanism, as previously pointed by DFT calculations. A DFT-based microkinetic model that predicts the reaction performance at different conditions was built. The model was validated against experimental data, showing remarkable agreement, which further confirmed the reliability of the DFT data

  14. Highly Dispersed Alloy Catalyst for Durability

    Energy Technology Data Exchange (ETDEWEB)

    Murthi, Vivek S.; Izzo, Elise; Bi, Wu; Guerrero, Sandra; Protsailo, Lesia

    2013-01-08

    Achieving DOE's stated 5000-hr durability goal for light-duty vehicles by 2015 will require MEAs with characteristics that are beyond the current state of the art. Significant effort was placed on developing advanced durable cathode catalysts to arrive at the best possible electrode for high performance and durability, as well as developing manufacturing processes that yield significant cost benefit. Accordingly, the overall goal of this project was to develop and construct advanced MEAs that will improve performance and durability while reducing the cost of PEMFC stacks. The project, led by UTC Power, focused on developing new catalysts/supports and integrating them with existing materials (membranes and gas diffusion layers (GDLs)) using state-of-the-art fabrication methods capable of meeting the durability requirements essential for automotive applications. Specifically, the project work aimed to lower platinum group metals (PGM) loading while increasing performance and durability. Appropriate catalysts and MEA configuration were down-selected that protects the membrane, and the layers were tailored to optimize the movements of reactants and product water through the cell to maximize performance while maintaining durability.

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

    Institute of Scientific and Technical Information of China (English)

    Ling QIAN; Zi Feng YAN

    2003-01-01

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

  16. Autothermal reforming of biogas over a monolithic catalyst

    Institute of Scientific and Technical Information of China (English)

    Sadao Araki; Naoe Hino; Takuma Mori; Susumu Hikazudani

    2010-01-01

    This study focused on measurement of the autothermal reforming of biogas over a Ni based monolithic catalyst.The effects of the steam/CH4 (S/C) ratio,O2/CH4 (O2/C) ratio and temperature were investigated.The CH4 conversions were higher under all examined temperatures than the equilibrium conversion calculated using the blank outlet temperature,because the catalyst layer was heated by the exothermic catalytic partial oxidation reaction.The CH4 conversion increased with increasing O2/C ratio.Moreover,the CH4 conversion was higher than the equilibrium conversion calculated using the blank outlet temperature for O2/C>0.42 and reached about 100% at O2/C=0.55.However,the hydrogen concentration decreased for O2/C>0.45 because hydrogen was combusted to steam in the presence of excess oxygen.On the other hand,the hydrogen and CO2 concentrations increased and the CO concentration decreased with increasing S/C ratio.As a result,it was found that the highest hydrogen concentrations and CH4 conversions were attained at the O2/C ratios of 0.45-0.55 and the S/C ratios of 1.5-2.5.Moreover,the H2/CO ratio could also be controlled in the range from about 2 to 3.5 to give at least 90% CH4 conversion,by regulating the O2/C or S/C ratios.

  17. Ni-Based Catalysts for Low Temperature Methane Steam Reforming: Recent Results on Ni-Au and Comparison with Other Bi-Metallic Systems

    Directory of Open Access Journals (Sweden)

    Anna M. Venezia

    2013-06-01

    Full Text Available Steam reforming of light hydrocarbons provides a promising method for hydrogen production. Ni-based catalysts are so far the best and the most commonly used catalysts for steam reforming because of their acceptably high activity and significantly lower cost in comparison with alternative precious metal-based catalysts. However, nickel catalysts are susceptible to deactivation from the deposition of carbon, even when operating at steam-to-carbon ratios predicted to be thermodynamically outside of the carbon-forming regime. Reactivity and deactivation by carbon formation can be tuned by modifying Ni surfaces with a second metal, such as Au through alloy formation. In the present review, we summarize the very recent progress in the design, synthesis, and characterization of supported bimetallic Ni-based catalysts for steam reforming. The progress in the modification of Ni with noble metals (such as Au and Ag is discussed in terms of preparation, characterization and pretreatment methods. Moreover, the comparison with the effects of other metals (such as Sn, Cu, Co, Mo, Fe, Gd and B is addressed. The differences of catalytic activity, thermal stability and carbon species between bimetallic and monometallic Ni-based catalysts are also briefly shown.

  18. Hydrogen production by low-temperature reforming of bioethanol over ZnO-supported Co-Ni and Co-Cu catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Llorca, J.; Homs, N.; Ramirez de la Piscina, P.

    2005-07-01

    The use of a renewable, non-toxic biomass-derived source, like bioethanol, to produce hydrogen is actually very attractive. In such domain, the search of a catalytic system highly effective for the selective steam-reforming process is of current research interest, CH3CH2OH+3H2O.6H2+2CO2. The steam-reforming of ethanol involves numerous steps and usually competes with several parallel reactions that originate undesired products like CO and CH4, resulting in lower hydrogen yields and difficult practical application. Copper- and nickel-based catalysts, including catalysts containing both metals, have been extensively studied in the steam-reforming of ethanol [1-3]. It has been well established that copper favours the dehydrogenation reaction and nickel the breaking of C-C bonds. Moreover, the presence of basic supports and Cu-Ni alloys prevent the formation of carbon deposits [1-3]. On the other hand, we have shown that ZnO-supported cobalt catalysts are very selective to hydrogen and CO2 from the steam reforming of bioethanol mixtures below 673 K [4]. In addition, sodium addition to ZnO-supported cobalt catalysts results in a major stability by suppressing the deposition of carbon [5]. Here we present the catalytic behaviour at low temperature of sodium-promoted, bimetallic cobalt-nickel and cobalt copper catalysts supported on ZnO and compare their performance with mono metallic ZnO-supported Ni and Cu samples. Catalysts have been tested in the steam-reforming reaction of bioethanol at atmospheric pressure (C2H5OH:H2O1:4 v/v) and characterised by means of X-ray diffraction (XRD), transmission electron microscopy techniques (TEM) and X-ray photoelectron spectroscopy (XPS) before and after reaction. The effect of introduction of copper or nickel on cobalt-based catalysts is discussed in relation to their catalytic performances. (Author)

  19. Investigation of Aerogel/Xerogel Catalysts for Autothermal Reforming of JP-8

    Science.gov (United States)

    2013-12-19

    supercritical conditions, where CO2 is typically used as the supercritical fluid. This conventional approach has proven to be costly as well as time...reforming catalysts for hydrogen production . Conversion of hydrocarbon fuels, such as gasoline, methanol , diesel, JP-8 and isobutanol by reforming is an...and Ar analysis (Carboxen 1000). The fractional conversion of n-Dodecane resulting from reforming (Xref) and the product yields of H2, CO, CO2 , and C1

  20. Methods of reforming hydrocarbon fuels using hexaaluminate catalysts

    Science.gov (United States)

    Gardner, Todd H [Morgantown, WV; Berry, David A [Morgantown, WV; Shekhawat, Dushyant [Morgantown, WV

    2012-03-27

    A metal substituted hexaaluminate catalyst for reforming hydrocarbon fuels to synthesis gas of the general formula AB.sub.yAl.sub.12-yO.sub.19-.delta., A being selected from alkali metals, alkaline earth metals and lanthanide metals or mixtures thereof. A dopant or surface modifier selected from a transitions metal, a spinel of an oxygen-ion conductor is incorporated. The dopant may be Ca, Cs, K, La, Sr, Ba, Li, Mg, Ce, Co, Fe, Ir, Rh, Ni, Ru, Cu, Pe, Os, Pd, Cr, Mn, W, Re, Sn, Gd, V, Ti, Ag, Au, and mixtures thereof. The oxygen-ion conductor may be a perovskite selected from M'RhO.sub.3, M'PtO.sub.3, M'PdO.sub.3, M'IrO.sub.3, M'RuO.sub.3 wherein M'=Mg, Sr, Ba, La, Ca; a spinel selected from MRh.sub.2O.sub.4, MPt.sub.2O.sub.4, MPd.sub.2O.sub.4, MIr.sub.2O.sub.4, MRu.sub.2O.sub.4 wherein M=Mg, Sr, Ba, La, Ca and mixtures thereof; a florite is selected from M''O.sub.2.

  1. Tungsten Promoted Ni/Al2O3 Catalysts for Carbon Dioxide Reforming of Methane to Synthesis Gas

    Institute of Scientific and Technical Information of China (English)

    XIAO Tian-cun; Thomas Suhartanto; Andrew P. E. York; Malcolm L. H. Green

    2004-01-01

    A series of tungsten promoted alumina supported nickel catalysts has been prepared for the carbon dioxide reforming of methane to synthesis gas. The catalysts have been characterized by means of XRD, TEM,and Laser Raman spectroscopy. It is shown that the addition of tungsten to the nickel catalyst can stabilize the catalyst and increase the resistance to carbon deposition. Adding a suitable amount of tungsten can also increase the catalyst activity to be close to that of supported noble metal catalysts. The carburisation of the tungsten modified nickel catalyst decreases the catalyst activity at lower reaction temperatures(<1123K),but has no effect on the catalyst performance at higher reaction temperatures. The alumina supported nickel catalyst modified by 0. 67 % (mass fraction)WOs has the equivalent equilibrium constant of the dry reforming reaction to that of alumina supported 5% (mass fraction) Ru at 873 K, and also has a lower activation energy for dry reforming than the latter.

  2. Study of cerium-promoted rhodium alumina catalyst as a steam reforming catalyst for treatment of spent solvents

    Institute of Scientific and Technical Information of China (English)

    Hee-Chul Yang; Min-Woo Lee; Ho-Sang Hwang; Jei-Kwon Moon; Dong-Yong Chung

    2014-01-01

    This study attempted to develop an appropriate catalyst used for the steam reforming of gasified spent solvents. Rh2O3/ CeO2-Al2O3 catalysts with various CeO2 loadings were prepared and heated at different temperatures of 500 and 800 ºC, and their surface properties were studied using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron mi-croscopy (TEM), temperature programmed reduction (TPR) and Brumauer-Emmett-Teller (BET) analyses. Rhodium existed in the form of Rh2O3, regardless of the sample composition as well as the heating temperature. In the tested range of cerium addition (up to 12 times the rhodium mass), no significant changes in BET surface areas and binding energy corresponding to Rh 3d5/2were observed. Instead, the addition of cerium led to a greatly enhanced dispersion of rhodium nanoparticles, and no agglomeration of rhodium was observed for samples heated even at 800 ºC. Honeycomb monolith rhodium catalysts promoted with cerium were fabricated and tested for the steam reforming of a gasified spent solvent, mainly consisting of butylene (C4H8). The test results suggested that a ce-rium-promoted rhodium catalyst could be used as an appropriate reforming catalyst for treating low-quality non-methane hydrocar-bons without the formation of coke at high temperatures of up to 900 ºC.

  3. Influence of Yttrium and Ytterbium on Reaction Performance of Platinum-Rhenium Reforming Catalyst

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The influence of yttrium and ytterbium on the catalytic performance of Pt-Re reforming cata-lysts was studied in a continuous flow pressurized microreactor-chromatograph system and pilot unit. Theresults of micro-reactor test showed that both yttrium and ytterbium could improve the selectivity of Pt-Recatalysts for the conversion ofn-heptane as well as MCP into aromatics, but also suppressed their activityas well. Pilot test results showed that yttrium and ytterbium enhanced both the selectivity and activity ofPt-Re catalysts for naphtha reforming. Yttrium showed more improvement than ytterbium. The perfor-mance difference between microreactor test and pilot test might be due to the difference in improvement ofcatalytic stability of yttrium or ytterbium modified Pt-Re catalysts. Yttrium and ytterbium improved thecoking resistance of yttrium or ytterbium modified Pt-Re catalysts. TEM determination results indicatedthat both yttrium and ytterbium had improved the thermal stability of Pt-Re catalysts.

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

    Science.gov (United States)

    Cho, Su Hyun; Moon, Dong Ju

    2011-08-01

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

  5. Methanol Steam Reforming Catalysts for Fuel Cell Driven Electric Vehicles

    Institute of Scientific and Technical Information of China (English)

    Yongfeng Li; Xinfa Dong; Weiming Lin

    2003-01-01

    Cu/ZnAlO catalysts derived from hydroxycarbonate precursors containing hydrotalcite-likelayered double hydroxides (LDHs) were studied. The influence on the performance of the catalysts wasalso studied when the Al in the Cu/ZnAlO catalyst was partly or completely replaced by Zr or Ce.

  6. Ethanol dry reforming for syngas production over Ir/CeO2 catalyst

    Institute of Scientific and Technical Information of China (English)

    侯腾飞; 雷雨声; 张绍印; 张江华; 蔡伟杰

    2015-01-01

    Syngas production from CO2 reforming of ethanol over an Ir/CeO2 catalyst was investigated. Catalysts characterization was conducted by X-ray diffraction (XRD), temperature programmed reduction (TPR), transmission electron microscopy (TEM) and temperature programmed oxidation (TPO). The Ir/CeO2 catalyst was more active and stable toward syngas formation (molar ratio~1). The superior catalytic performance was interpreted in terms of the strong interaction between Ir particles and ceria support which was crucial for efficient ethanol/CO2 activation and coke removal on the catalyst surface.

  7. Effects of Current on Microcosmic Properties of Catalyst and Reforming of Bio-oil

    Institute of Scientific and Technical Information of China (English)

    Li-xia Yuan; Tong-qi Ye; Fei-yan Gong; Quan-xin Li

    2009-01-01

    Highly effective production of hydrogen from bio-oil was achieved by using a low-temperature electrochemical catalytic reforming approach over the conventional Ni-based reforming cat-alyst (NiO-Al2O3), where an AC electronic current passed through the catalyst bed. The promoting effects of current on the bio-oil reforming were studied. It was found that the performance of the bio-oil reforming was remarkably enhanced by the current which passed through the catalyst. The effects of currents on the microcosmic properties of the catalyst, including the Brunauer-Emmett-Teller (BET) surface area, pore diameter, pore volume, the size of the crystallites and the reduction level of NiO into Ni, were carefully characterized by BET, X-ray diffraction, X-ray photoelectron spectroscopy, and scanning electron microscope. The desorption of the thermal electrons from the electrified catalyst was directly observed by the TOF (time of flight) measurements. The mechanism of the electrochemical catalytic reforming of bio-oil is discussed based on the above investigation.

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

    Institute of Scientific and Technical Information of China (English)

    Mei Hua YANG; Rong Bin ZHANG; Feng Yi LI

    2004-01-01

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

  9. Catalyst Deactivation Simulation Through Carbon Deposition in Carbon Dioxide Reforming over Ni/CaO-Al2O3 Catalyst

    Directory of Open Access Journals (Sweden)

    Istadi Istadi

    2011-11-01

    Full Text Available Major problem in CO2 reforming of methane (CORM process is coke formation which is a carbonaceous residue that can physically cover active sites of a catalyst surface and leads to catalyst deactivation. A key to develop a more coke-resistant catalyst lies in a better understanding of the methane reforming mechanism at a molecular level. Therefore, this paper is aimed to simulate a micro-kinetic approach in order to calculate coking rate in CORM reaction. Rates of encapsulating and filamentous carbon formation are also included. The simulation results show that the studied catalyst has a high activity, and the rate of carbon formation is relatively low. This micro-kinetic modeling approach can be used as a tool to better understand the catalyst deactivation phenomena in reaction via carbon deposition. Copyright © 2011 BCREC UNDIP. All rights reserved.(Received: 10th May 2011; Revised: 16th August 2011; Accepted: 27th August 2011[How to Cite: I. Istadi, D.D. Anggoro, N.A.S. Amin, and D.H.W. Ling. (2011. Catalyst Deactivation Simulation Through Carbon Deposition in Carbon Dioxide Reforming over Ni/CaO-Al2O3 Catalyst. Bulletin of Chemical Reaction Engineering & Catalysis, 6 (2: 129-136. doi:10.9767/bcrec.6.2.1213.129-136][How to Link / DOI: http://dx.doi.org/10.9767/bcrec.6.2.1213.129-136 || or local:  http://ejournal.undip.ac.id/index.php/bcrec/article/view/1213 ] | View in  |  

  10. Accelerating process and catalyst development in reforming reactions with high throughput technologies under industrially relevant conditions

    Energy Technology Data Exchange (ETDEWEB)

    Schunk, S.A.; Bollmann, G.; Froescher, A.; Kaiser, H.; Lange de Oliveira, A.; Roussiere, T.; Wasserschaff, G. [hte Aktiengesellschaft, Heidelberg (Germany); Domke, I. [BASF SE, Ludwigshafen (Germany)

    2010-12-30

    The generation of hydrogen via reforming of a variety of carbon containing feed-stocks in the presence of water is up to date one of the most versatile technologies for the production of hydrogen and syngas. Although these reforming technologies are in principle well established, understood and commercialized, there are still a number of technological challenges that are not solved up to a satisfactorily degree and there is a constant demand for appropriate answers to the challenges posed. High throughput experimentation can be a valuable tool in helping accelerate the development of suitable solutions on the catalyst and process development side. In order to be able to generate test data that are close or identical to process relevant conditions, hte has developed a new technology portfolio of test technologies named Stage-IV technology. In contrast to earlier developments which address more small scale testing on the basis of catalyst volumes of 1ml up to 10 ml under isothermal conditions, our new technology portfolio offers the advantage of test volumes at sub-pilot scale also realizing reactor dimensions close to technical applications. This does not only ensure a good mimic of the hydrodynamic conditions of the technical scale, but also allows a fingerprinting of features like temperature gradients in the catalyst bed which play a large role for catalyst performance. Apart from catalyst tests with granulates when screening for optimized catalyst compositions, the units are designed to accommodate tests with shaped catalysts. In order to demonstrate how these technologies can accelerate catalyst and process development we have chosen technically challenging application examples: (I) Pre-reforming and reforming of methane based feeds which accelerate coking and catalyst deactivation. Higher reaction pressures, high CO{sub 2} contents in the feedgas (which occur typically in sources like bio-gas or certain types of natural gas), the presence of higher alkanes

  11. Hydrocarbon reforming catalysts and new reactor designs for compact hydrogen generators

    Energy Technology Data Exchange (ETDEWEB)

    Schaefer, A.; Schwab, E.; Urtel, H. [BASF SE, Ludwigshafen (Germany); Farrauto, R. [BASF Catalysts LLC, Iselin, NJ (United States)

    2010-12-30

    A hydrogen based future energy scenario will use fuel cells for the conversion of chemically stored energy into electricity. Depending upon the type of fuel cell, different specifications will apply for the feedstock which is converted in the cell, ranging from very clean hydrogen for PEM-FC's to desulfurized methane for SOFC and MCFC technology. For the foreseeable future, hydrogen will be supplied by conventional reforming, however operated in compact and dynamic reformer designs. This requires that known catalyst formulations are offered in specific geometries, giving flexibility for novel reactor design options. These specific geometries can be special tablet shapes as well as monolith structures. Finally, also nonhydrocarbon feedstock might be used in special applications, e.g. bio-based methanol and ethanol. BASF offers catalysts for the full process chain starting from feedstock desulfurization via reforming, high temperature shift, low temperature shift to CO fine polishing either via selective oxidation or selective methanation. Depending upon the customer's design, most stages can be served either with precious metal based monolith solutions or base metal tablet solutions. For the former, we have taken the automobile catalyst monolith support and extended its application to the fuel cell hydrogen generation. Washcoats of precious metal supported catalysts can for example be deposited on ceramic monoliths and/or metal heat exchangers for efficient generation of hydrogen. Major advantages are high through puts due to more efficient heat transfer for catalysts on metal heat exchangers, lower pressure drop with greater catalyst mechanical and thermal stability compared to particulate catalysts. Base metal tablet catalysts on the other hand can have intrinsic cost advantages, larger fractions of the reactor can be filled with active mass, and if produced in unconventional shape, again novel reactor designs are made possible. Finally, if it comes to

  12. Identification of non-precious metal alloy catalysts for selective hydrogenation of acetylene

    DEFF Research Database (Denmark)

    Studt, Felix; Abild-Pedersen, Frank; Bligaard, Thomas

    2008-01-01

    The removal of trace acetylene from ethylene is performed industrially by palladium hydrogenation catalysts ( often modified with silver) that avoid the hydrogenation of ethylene to ethane. In an effort to identify catalysts based on less expensive and more available metals, density functional...... calculations were performed that identified relations in heats of adsorption of hydrocarbon molecules and fragments on metal surfaces. This analysis not only verified the facility of known catalysts but identified nickel- zinc alloys as alternatives. Experimental studies demonstrated that these alloys...

  13. Study of The Pd-B/γ-Al2O3 Amorphous Alloy Catalyst

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The Pd-B/γ-Al2O3 amorphous alloy catalyst and Pd/γ-Al2O3 crystalline metal catalyst were prepared by KBH4 reduction and routine impregnation, respectively. Pd-B/γ-A12O3 and Pd/γ-A12O3 catalysts were characterized by XRD and SEM. It was found that the catalytic activity of the Pd-B/γ-A12O3 amorphous alloy catalyst was higher than that of the Pd/γ-A12O3crystalline metal catalyst in the anthraquinone hydrogenation.

  14. Investigation of the promoting effect of Mn on a Pt/C catalyst for the steam and aqueous phase reforming of glycerol

    Energy Technology Data Exchange (ETDEWEB)

    Bossola, Filippo; Pereira-Hernández, Xavier Isidro; Evangelisti, Claudio; Wang, Yong; Dal Santo, Vladimiro

    2017-05-01

    The catalytic performances in steam reforming (SR) and aqueous phase reforming (APR) of glycerol of a bimetallic Pt-Mn catalyst supported on activated carbon are investigated and correlated with the surface properties of the catalyst. Under SR conditions, Mn showed a significant promoting effect over Pt/C, both in terms of hydrogen production rate and conversion, with a higher selectivity toward the glycerol dehydration products. Upon addition of Mn the amount of strong Lewis acid sites increased, promoting the dehydration of glycerol and favoring the CAO over CAC cleavage at expenses of hydrogen selectivity. Conversely, under APR conditions, a slightly higher hydrogen selectivity and only minimal enhancement in hydrogen production were found, while the products selectivity was comparable to Pt/C. Most of Mn leached into the aqueous media, but the remaining (<5% of the fresh parent sample) might be alloyed with Pt and promote the CO desorption from neighbor Pt sites.

  15. Sulfur Tolerant Magnesium Nickel Silicate Catalyst for Reforming of Biomass Gasification Products to Syngas

    OpenAIRE

    Swartz, Scott L.; Paul H. Matter; Gene B. Arkenberg; Long, Richard Q.; Scott M. Monfort

    2012-01-01

    Magnesium nickel silicate (MNS) has been investigated as a catalyst to convert tars and light hydrocarbons to syngas (CO and H2) by steam reforming and CO2 reforming in the presence of H2S for biomass gasification process at NexTech Materials. It was observed that complete CH4 conversion could be achieved on MNS catalyst granules at 800–900 °C and a space velocity of 24,000 mL/g/h in a simulated biomass gasification stream. Addition of 10–20 ppm H2S to the feed had no apparent impact on CH4 c...

  16. Development of Ni-Based Catalysts for Steam Reforming of Tar Derived from Biomass Pyrolysis

    Institute of Scientific and Technical Information of China (English)

    Dalin LI; Yoshinao NAKAGAWA; Keiichi TOMISHIGE

    2012-01-01

    Nickel catalysts are effective for the steam reforming of tar derived from biomass pyrolysis,but the improvement is needed in terms of activity,stability,suppression of coke deposition and aggregation,and regeneration.Our recent development of Ni-based catalysts for the steam reforming of tar is reviewed including the modification with CeO2 (or MnO),trace Pt,and MgO.The role of additives such as CeO2,MnO,Pt,and MgO is also discussed.

  17. Stability and activity of molybdenum carbide catalysts for the oxidative reforming of methane

    Science.gov (United States)

    Lamont, David Charles

    Molybdenum carbide catalysts have been studied for oxidative reforming, in particular, the effect on reforming activity of the method by which they were synthesized, their stability under conditions of varying mass transfer, and the measurement of their inherent reaction kinetics. These catalysts show promise as possible alternatives to both conventional supported nickel catalysts, as well as to the rare and expensive noble metal catalysts. Samples of Mo 2C were synthesized in house and compared to a commercial sample of Mo2C for the CO2 (dry) reforming of methane. It was found that high surface areas, previously thought to be important for activity, were not a property of the Mo2C, but instead were attributable to large amounts of excess carbon. This carbon had a detrimental effect on catalyst stability under dry reforming conditions, because it enhanced deposition of refractory carbon via methane cracking. The commercial sample of Mo 2C, while of low surface area and containing no excess carbon, behaved more stably over time. In another investigation, Mo2C was studied for its stability under varying mass transfer conditions, because of evidence showing that the Mo2C can undergo redox chemistry at reforming conditions. Under dry reforming conditions, it was found that some feed mixtures are net oxidizing, but that oxidation in the presence of such feed mixtures could be prevented by operating under mass transfer limited conditions, which resulted in sufficiently high partial pressures of CO and H2 in the catalyst boundary layer. Similar stability was achieved by co-feeding CO to the catalyst bed, which allowed for stable operation under conditions that were not mass transfer limited. Using this approach, measurements of the intrinsic reaction kinetics of Mo2C for dry reforming were successfully achieved. These results pointed to a strong dependence of dry reforming rate on both CH4 and CO2 partial pressures, as well as evidence for a reaction mechanism unique from

  18. Steam Reforming of Glycerol Over Nano Size Ni-Ce/LaAlO3 Catalysts.

    Science.gov (United States)

    Kim, Seong-Hak; Go, Yoo-Jin; Park, Nam-Cook; Kim, Jong-Ho; Kim, Young-Chul; Moon, Dong-Ju

    2015-01-01

    In this work, hydrogen production from glycerol by Steam Reforming (SR) was studied by Ni-Ce catalysts supported on LaAlO3 perovskite in order to effect of the cerium loading amount and the reaction conditions. Nano size Ni-Ce/LaAlO3 catalysts were prepared by precipitation method. The structure of the catalysts was characterized by XRD analysis. The morphology, dispersion and the reduction properties of catalysts was examined by SEM, TEM, H2-chemisorption and TPR, respectively. It was found that 15 wt% Ni-5 wt% Ce/LaAlO3 catalyst showed the highest glycerol conversion and hydrogen selectivity. In addition, the catalyst also showed the high carbon dioxide selectivity and the lowest methane selectivity. The results indicate that the catalyst promotes methane reforming reaction. The highest activity in the 15 wt% Ni-5 wt% Ce/LaAlO3 was attributed to the proper cerium loading amount. Moreover, the lowest metal crystal size and rise in active site were found to have an effect on catalytic activity and hydrogen selectivity. The 15 wt% Ni-5 wt% Ce/LaAlO3 catalyst exhibited excellent performance with respect to hydrogen production at reaction temperature of 450 degrees C, at atmospheric pressure, 20 wt% glycerol solution and GHSV = 6,000 mL/g-cat x hr.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-11-25

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

  20. Catalyst Deactivation and Regeneration in Low Temperature Ethanol Steam Reforming with Rh/CeO2-ZrO2 Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Roh, Hyun-Seog; Platon, Alex; Wang, Yong; King, David L.

    2006-08-01

    Rh/CeO2-ZrO2 catalysts with various CeO2/ZrO2 ratios have been applied to H2 production from ethanol steam reforming at low temperatures. The catalysts all deactivated with time on stream (TOS) at 350 C. The addition of 0.5% K has a beneficial effect on catalyst stability, while 5% K has a negative effect on catalytic activity. The catalyst could be regenerated considerably even at ambient temperature and could recover its initial activity after regeneration above 200 C with 1% O2. The results are most consistent with catalyst deactivation due to carbonaceous deposition on the catalyst.

  1. Hydrogen Production via Glycerol Dry Reforming over La-Ni/Al2O3 Catalyst

    Directory of Open Access Journals (Sweden)

    Kah Weng Siew

    2013-12-01

    Full Text Available Glycerol (a bio-waste generated from biodiesel production has been touted as a promising bio-syngas precursor via reforming route. Previous studies have indicated that carbon deposition is the major performance-limiting factor for nickel (Ni catalyst during glycerol steam reforming. In the current paper, dry (CO2-reforming of glycerol, a new reforming route was carried out over alumina (Al2O3-supported non-promoted and lanthanum-promoted Ni catalysts. Both sets of catalysts were synthesized via wet co-impregnation procedure. The physicochemical characterization of the catalyst showed that the promoted catalyst possessed smaller metal crystallite size, hence higher metal dispersion compared to the virgin Ni/Al2O3 catalyst. This was also corroborated by the surface images captured by the FESEM analysis. In addition, BET surface area measurement gave 92.05m²/g for non-promoted Ni catalyst whilst promoted catalysts showed an average of 1 to 6% improvement depending on the La loading. Reaction studies at 873 K showed that glycerol dry reforming successfully produced H2 with glycerol conversion and H2 yield that peaked at 9.7% and 25% respectively over 2wt% La content. The optimum catalytic performance by 2%La-Ni/Al2O3 can be attributed to the larger BET surface area and smaller crystallite size that ensured accessibility of active catalytic sites.  © 2013 BCREC UNDIP. All rights reservedReceived: 12nd May 2013; Revised: 7th October 2013; Accepted: 16th October 2013[How to Cite: Siew, K.W., Lee, H.C., Gimbun, J., Cheng, C.K. (2013. Hydrogen Production via Glycerol Dry Reforming over La-Ni/Al2O3 Catalyst. Bulletin of Chemical Reaction Engineering & Catalysis, 8 (2: 160-166. (doi:10.9767/bcrec.8.2.4874.160-166][Permalink/DOI: http://dx.doi.org/10.9767/bcrec.8.2.4874.160-166

  2. Methanol Steam Reforming Reactions on CuZn(Zr)AlO Catalyst

    Institute of Scientific and Technical Information of China (English)

    Yongfeng Li; Xinfa Dong; Weiming Lin

    2004-01-01

    The catalytic performances of methanol steam reforming reactions on CuZn(Zr)AlO catalysts were studied. When the ZrO2 promoter was added to a CuZnAlO catalyst, its methanol conversion,H2 production and H2 selectivity improved greatly. By using the #COPZr-2 catalyst as an example,which exhibited the best catalytic performance, the optimized reaction conditions were established to be:250 ℃, 0.1 MPa, H2O/MeOH=1.3, WHSV=3.56 h-1, and without carrier gas. A 150 h stability test of the #COPZr-2 catalyst showed that the catalyst had good stability, as the methanol conversion and H2 production could be kept at 88% and 83% respectively. Moreover, outlet H2 and CO contents were >63%and 0.20%-0.31%, respectively.

  3. Nano-structured noble metal catalysts based on hexametallate architecture for the reforming of hydrocarbon fuels

    Energy Technology Data Exchange (ETDEWEB)

    Gardner, Todd H.

    2015-09-15

    Nano-structured noble metal catalysts based on hexametallate lattices, of a spinel block type, and which are resistant to carbon deposition and metal sulfide formation are provided. The catalysts are designed for the reforming of hydrocarbon fuels to synthesis gas. The hexametallate lattices are doped with noble metals (Au, Pt, Rh, Ru) which are atomically dispersed as isolated sites throughout the lattice and take the place of hexametallate metal ions such as Cr, Ga, In, and/or Nb. Mirror cations in the crystal lattice are selected from alkali metals, alkaline earth metals, and the lanthanide metals, so as to reduce the acidity of the catalyst crystal lattice and enhance the desorption of carbon deposit forming moieties such as aromatics. The catalysts can be used at temperatures as high as 1000.degree. C. and pressures up to 30 atmospheres. A method for producing these catalysts and applications of their use also is provided.

  4. Preparation and performance of rare earth Zr catalyst for reforming waste plastics cracking product

    Institute of Scientific and Technical Information of China (English)

    袁兴中; 曾光明; 陈晓青; 陈志勇; 鄢钢

    2003-01-01

    The rare earth Zr catalyst, whose carrier was Al2O3, was prepared by co-precipitation with Zr(NO3)2,Al(NO3 )3, and(NH2)2CO as the raw materials. The obtained catalyst was used to reform the waste plastic crackingproduct. As the Zr content in the catalyst increases, the yields of gasoline, gas, and the rate of carbon deposition in-crease, but the yields of diesel and heavy oil decrease. The optimum Zr content of the catalyst is 5%. At 290 ℃,with this most suitable catalyst, the yield of liquid fuel oil is the highest, about 86.10%, and research octance num-ber(RON) of the gasoline is 92.15.

  5. Aqueous phase reforming of glycerol over the Pd loaded Ni/Al2O3 catalysts.

    Science.gov (United States)

    Karthikeyan, Dhanapalan; Shin, Gwan Su; Moon, Dong Ju; Kim, Jong Ho; Park, Nam Cook; Kim, Young Chul

    2011-02-01

    Bifunctional catalysts containing (0.5-1.5 wt%) palladium and 15 wt% of Nickel supported on gamma-Al2O3 were prepared via an impregnation technique and catalysts were characterzed by XRD BET surface area and SEM, respectively. The aqueous phase reforming of glycerol (APR) was conducted over alumina-supported catalysts at different reaction conditions for catalytic activity. Finally, we concluded that the 1.0 wt% Pd 15 wt% Ni/gamma-Al2O3 catalyst evidences higher conversion, hydrogen selectivity, lower alkane selectivity and CO production. This indicate that Pd loaded Ni/gamma-Al2O3 could be a potential catalyst for the APR of glycerol.

  6. Hydrogen and/or syngas from steam reforming of glycerol. Study of platinum catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Pompeo, Francisco; Santori, Gerardo; Nichio, Nora N. [Facultad de Ingenieria, Universidad Nacional de La Plata, 1 esq 47, 1900 La Plata (Argentina); CINDECA, Facultad de Ciencias Exactas, Universidad Nacional de La Plata-CONICET, 47 N 257, 1900 La Plata (Argentina)

    2010-09-15

    In the present work, Pt catalysts prepared on different supports were evaluated in order to apply them in the steam reforming of glycerol reaction to obtain hydrogen and/or synthesis gas at temperatures lower than 450 C. A strong support effect on the behavior of catalysts was determined. The presence of intermediate products allowed to propose a scheme of reactions that would explain the results obtained at different space times and temperatures studied. Materials with acid properties demonstrated low activity to gaseous products, with formation of lateral products due to dehydration and condensation reactions, which would lead to coke formation and to a fast catalyst deactivation. On the contrary, the catalyst prepared with a support with neutral properties permitted to obtain a catalyst with excellent activity levels to gaseous products, high selectivity to H{sub 2}, and a very well stability in time. (author)

  7. Effect of initial nickel particle size on stability of nickel catalysts for aqueous phase reforming

    NARCIS (Netherlands)

    Haasterecht, Van Tomas; Swart, Marten; Jong, De Krijn P.; Bitter, J.H.

    2016-01-01

    The deactivation behavior by crystallite growth of nickel nanoparticles on various supports (carbon nanofibers, zirconia, SiC, α-Al2O3 and γ-Al2O3) was investigated in the aqueous phase reforming of ethylene glycol. Supported Ni catalysts of ∼10 wt% were prepared by impregnation of carbon nanofibers

  8. On the origin of reactivity of steam reforming of ethylene glycol on supported Ni catalysts.

    Science.gov (United States)

    Li, Shuirong; Zhang, Chengxi; Zhang, Peng; Wu, Gaowei; Ma, Xinbin; Gong, Jinlong

    2012-03-28

    This paper describes a strategy for producing hydrogen via steam reforming of ethylene glycol over supported nickel catalysts. Nickel plays a crucial role in conversion of ethylene glycol and production of hydrogen, while oxide supports affect product distribution of carbonaceous species. A plausible reaction pathway is proposed based on our results and the literature.

  9. Oxidative steam reforming of ethanol over carbon nanofiber supported Co catalysts

    NARCIS (Netherlands)

    da Silva, A.L.M.; Mattos, L.V.; den Breejen, J.P.; Bitter, J.H.; de Jong, K.P.; Noronha, F.B.

    2011-01-01

    The effect of the cobalt particle size in the ethanol oxidative steam reforming reaction for hydrogen production was investigated using cobalt on carbon nanofiber catalysts. The smallest (4 nm) were quite stable during OSR reaction but significant carbon formation was detected.

  10. Steam reforming of phenol over Ni-based catalysts - A comparative study

    NARCIS (Netherlands)

    Matas Güell, B.; Babych, Igor V.; Lefferts, Leonardus; Seshan, Kulathuiyer

    2011-01-01

    The influence of the support in the steam reforming of phenol at 700 °C has been examined over Ni/K-La-ZrO2 and Ni/Ce-ZrO2. Both catalysts exhibited high activity and good stability in terms of phenol conversion. However, Ni/K-La-ZrO2 showed a pronounced change in product distribution with TOS,

  11. Steam and CO2 reforming of methane over a Ru/ZrO2 catalyst

    DEFF Research Database (Denmark)

    Jakobsen, Jon Geest; Jørgensen, T.L.; Chorkendorff, Ib;

    2010-01-01

    The kinetics of methane steam reforming over a Ru/ZrO2 catalyst was studied at 1.3 bar total pressure and in the temperature range 425-575 degrees C. These data were fitted by combining a reactor model with a series of kinetic models. The best fit was obtained by a model with methane dissociative...

  12. Design of Multiple Metal Doped Ni Based Catalyst for Hydrogen Generation from Bio-oil Reforming at Mild-temperature

    Institute of Scientific and Technical Information of China (English)

    Li-xia Yuan; Fang Ding; Jian-ming Yao; Xiang-song Chen; Wei-wei Liu; Jin-yong Wu; Fei-yan Gong

    2013-01-01

    A new kind of multiple metal (Cu,Mg,Ce) doped Ni based mixed oxide catalyst,synthesized by the co-precipitation method,was used for efficient production of hydrogen from bio-oil reforming at 250-500 ℃.Two reforming processes,the conventional steam reforming (CSR) and the electrochemical catalytic reforming (ECR),were performed for the bio-oil reforming.The catalyst with an atomic mol ratio of Ni∶Cu∶Mg∶Ce∶Al=5.6∶1.1∶1.9∶1.0∶9.9 exhibited very high reforming activity both in CSR and ECR processes,reaching 82.8% hydrogen yield at 500 ℃ in the CSR,yield of 91.1% at 400 ℃ and 3.1 A in the ECR,respectively.The influences of reforming temperature and the current through the catalyst in the ECR were investigated.It was observed that the reforming and decomposition of the bio-oil were significantly enhanced by the current.The promoting effects of current on the decomposition and reforming processes of bio-oil were further studied by using the model compounds of biooil (acetic acid and ethanol) under 101 kPa or low pressure (0.1 Pa) through the time of flight analysis.The catalyst also shows high water gas shift activity in the range of 300-600 ℃.The catalyst features and alterations in the bio-oil reforming were characterized by the ICP,XRD,XPS and BET measurements.The mechanism of bio-oil reforming was discussed based on the study of the elemental reactions and catalyst characterizations.The research catalyst,potentially,may be a practical catalyst for high efficient production of hydrogen from reforning of bio-oil at mild-temperature.

  13. Highly loaded Ni-based catalysts for low temperature ethanol steam reforming

    Science.gov (United States)

    Wang, Tuo; Ma, Hongyan; Zeng, Liang; Li, Di; Tian, Hao; Xiao, Shengning; Gong, Jinlong

    2016-05-01

    This paper describes the design of high-loading Ni/Al2O3 catalysts (78 wt% Ni) for low temperature ethanol steam reforming. The catalysts were synthesized via both co-precipitation (COP) and impregnation (IMP) methods. All the catalysts were measured by N2 adsorption-desorption, XRD, H2-TPR, and H2 pulse chemisorption. The characterization results demonstrated that the preparation method and the loading significantly affected the nickel particle size, active nickel surface area and catalytic performance. Over COP catalysts, large nickel particles were presented in nickel aluminum mixed oxides. In comparison, IMP catalysts gained more ``free'' NiO particles with weak interaction with the aluminum oxide. Consequently, COP catalysts yielded smaller nickel particles and larger active nickel surface areas than those of IMP catalysts. High loading is beneficial for obtaining sufficient active nickel sites when nickel particles are dispersed via COP, whereas excessive nickel content is not desired for catalysts prepared by IMP. Specifically, the 78 wt% nickel loaded catalyst synthesized by COP possessed small nickel particles (~6.0 nm) and an abundant active nickel area (35.1 m2 gcat-1). Consequently, COP-78 achieved superior stability with 92% ethanol conversion and ~35% H2 selectivity at 673 K for 30 h despite the presence of a considerable amount of coke.

  14. A novel DME steam-reforming catalyst designed with fact database on-demand

    Science.gov (United States)

    Yamada, Yusuke; Mathew, Thomas; Ueda, Atsushi; Shioyama, Hiroshi; Kobayashi, Tetsuhiko

    2006-01-01

    Novel catalysts for dimethyl ether (DME) steam reforming (SR) were designed based on catalysis database on-demand. A catalyst library consisting of precious metals loaded on various metal oxides was tested for DME SR and its elemental reactions of DME hydrolysis and MeOH SR. Platinum loaded on alumina, Pt/Al 2O 3, shows high activity for DME SR as reported previously. The drawback of the catalyst was also confirmed; the formation of methane leading to the reduction of hydrogen formation. From the fact database for DME hydrolysis and MeOH SR built up with high-throughput experimentation tools, the high activity of Pt/Al 2O 3 for DME SR is owing to its high activity on DME hydrolysis because its activity on MeOH steam reforming is not remarkable. Based on these facts, novel catalysts were designed and achieved by physical mixing of Pt/Al 2O 3 which reveals high activity on DME hydrolysis with an active catalyst on MeOH steam reforming. By mixing of Pt/Al 2O 3 with Pd/Al 2O 3, methane formation was suppressed without loss of hydrogen production activity.

  15. The role of surface reactions on the active and selective catalyst design for bioethanol steam reforming

    Science.gov (United States)

    Benito, M.; Padilla, R.; Serrano-Lotina, A.; Rodríguez, L.; Brey, J. J.; Daza, L.

    In order to study the role of surface reactions involved in bioethanol steam reforming mechanism, a very active and selective catalyst for hydrogen production was analysed. The highest activity was obtained at 700 °C, temperature at which the catalyst achieved an ethanol conversion of 100% and a selectivity to hydrogen close to 70%. It also exhibited a very high hydrogen production efficiency, higher than 4.5 mol H 2 per mol of EtOH fed. The catalyst was operated at a steam to carbon ratio (S/C) of 4.8, at 700 °C and atmospheric pressure. No by-products, such as ethylene or acetaldehyde were observed. In order to consider a further application in an ethanol processor, a long-term stability test was performed under the conditions previously reported. After 750 h, the catalyst still exhibited a high stability and selectivity to hydrogen production. Based on the intermediate products detected by temperature programmed desorption and reaction (TPD and TPR) experiments, a reaction pathway was proposed. Firstly, the adsorbed ethanol is dehydrogenated to acetaldehyde producing hydrogen. Secondly, the adsorbed acetaldehyde is transformed into acetone via acetic acid formation. Finally, acetone is reformed to produce hydrogen and carbon dioxide, which were the final reaction products. The promotion of such reaction sequence is the key to develop an active, selective and stable catalyst, which is the technical barrier for hydrogen production by ethanol reforming.

  16. Ethanol steam reforming over Mg-Al mixed-oxide catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Coleman, L.J.; Hudgins, R.R.; Silveston, P.L.; Croiset, E. [Waterloo Univ., ON (Canada). Dept. of Chemical Engineering

    2007-07-01

    Eight magnesium-aluminium (Mg-Al) mixed oxides and magnesium oxide (MgO) and aluminium oxide (Al{sub 2}O{sub 3}) were studied in order to identify the most effective Mg-Al mixed oxide for hydrogen production via ethanol steam reforming. Co-precipitated precursors were calcinated to prepare the Mg-Al mixed oxides. Activity and selectivity of the mixed oxides for ethanol steam reforming were evaluated at 773 and 923 K. Results showed that all catalysts performed poorly during the steam reforming reaction, and produced low rates of hydrogen, carbon monoxide (CO) and carbon dioxide (CO{sub 2}). Catalysts with an MgAl{sub 2}O{sub 4} spinel crystal structure gave the best performance at both reaction temperatures. However, carbon deposits were discovered on all catalysts for reactions performed at 923 K. Co-precipitation resulted in more effective contact between the Mg and Al in the form of Mg-Al LDO and MgAL{sub 2}O{sub 3}. The absence of pure oxides suggested that Mg and Al were chemically coupled in the mixed oxide catalysts. Results of the study showed that the catalyst with an atomic ratio of 0.66 Mg1Al2 was the most active and achieved the highest rates of production for hydrogen. 14 refs., 3 tabs., 1 fig.

  17. The role of surface reactions on the active and selective catalyst design for bioethanol steam reforming

    Energy Technology Data Exchange (ETDEWEB)

    Benito, M. [Instituto de Catalisis y Petroleoquimica (CSIC), C/Marie Curie 2, Campus Cantoblanco, 28049 Madrid (Spain); Ciemat, Av. Complutense 22, 28040 Madrid (Spain); Padilla, R.; Serrano-Lotina, A.; Rodriguez, L.; Daza, L. [Instituto de Catalisis y Petroleoquimica (CSIC), C/Marie Curie 2, Campus Cantoblanco, 28049 Madrid (Spain); Brey, J.J. [Hynergreen Technologies, Av. Buhaira 2, 41018 Sevilla (Spain)

    2009-07-01

    In order to study the role of surface reactions involved in bioethanol steam reforming mechanism, a very active and selective catalyst for hydrogen production was analysed. The highest activity was obtained at 700 C, temperature at which the catalyst achieved an ethanol conversion of 100% and a selectivity to hydrogen close to 70%. It also exhibited a very high hydrogen production efficiency, higher than 4.5 mol H{sub 2} per mol of EtOH fed. The catalyst was operated at a steam to carbon ratio (S/C) of 4.8, at 700 C and atmospheric pressure. No by-products, such as ethylene or acetaldehyde were observed. In order to consider a further application in an ethanol processor, a long-term stability test was performed under the conditions previously reported. After 750 h, the catalyst still exhibited a high stability and selectivity to hydrogen production. Based on the intermediate products detected by temperature programmed desorption and reaction (TPD and TPR) experiments, a reaction pathway was proposed. Firstly, the adsorbed ethanol is dehydrogenated to acetaldehyde producing hydrogen. Secondly, the adsorbed acetaldehyde is transformed into acetone via acetic acid formation. Finally, acetone is reformed to produce hydrogen and carbon dioxide, which were the final reaction products. The promotion of such reaction sequence is the key to develop an active, selective and stable catalyst, which is the technical barrier for hydrogen production by ethanol reforming. (author)

  18. Using Mechanical Alloying to Create Bimetallic Catalysts for Vapor-Phase Carbon Nanofiber Synthesis

    Directory of Open Access Journals (Sweden)

    Laura Guevara

    2015-10-01

    Full Text Available Carbon nanofibers were generated over bimetallic catalysts in an atmospheric pressure chemical vapor deposition (APCVD reactor. Catalyst compositions of Fe 30 at%, Cu and Ni 30 at% and Cu were mechanically alloyed using high-energy ball milling over durations of 4, 8, 12, 16, and 20 h. The catalyst powders were then used to produce carbon nanofibers in ethylene and hydrogen (4:1 at temperatures of 500, 550, and 600 °C. The microstructures of the catalysts were characterized as a function of milling time as well as at deposition temperature. The corresponding carbon deposition rates were assessed and are correlated to the microstructural features of each catalyst. The milling process directly determines the performance of each catalyst toward carbon deposition, and both catalysts performed comparably to those made by traditional co-precipitation methods. Considerations in miscible and immiscible nanostructured alloy systems are discussed.

  19. Nickel ferrite spinel as catalyst precursor in the dry reforming of methane:Synthesis, characterization and catalytic properties

    Institute of Scientific and Technical Information of China (English)

    Rafik Benrabaa; Hamza Boukhlouf; Axel L(o)fberg; Annick Rubbens; Rose-N(o)elle Vannier; Elisabeth Bordes-Richard; Akila Barama

    2012-01-01

    Dry reforming of methane by CO2 using nickel ferrite as precursor of catalysts was investigated.Nickel ferrite crystalline particles were prepared by coprecipitation of nitrates with NaOH or ammonia followed by calcination,or by hydrothermal synthesis without calcination step.The textural and structural properties were determined by a number of analysis methods,including X-ray diffraction (XRD),Raman spectroscopy and X-ray photoelectron spectroscopy (XPS),among which X-ray diffraction (XRD) was at room and variable temperatures.All synthesized oxides showed the presence of micro or nanoparticles of NiFe2O4 inverse spinel,but Fe2O3 (hematite) was also present when ammonia was used for coprecipitation.The reducibility by hydrogen was studied by temperature-programmed reduction (TPR) and in situ XRD,which showed the influence of the preparation method.The surface area (BET),particle size (Rietveld refinement),as well as surface Ni/Fe atomic ratio (XPS) and the behavior upon reduction varied according to the synthesis method.The catalytic reactivity was investigated using isopropanol decomposition to determine the acid/base properties.The catalytic performance of methane reforming with CO2 was measured with and without the pre-treatment of catalysts under H2 in 650-800 ℃ range.The catalytic conversions of methane and CO2 were quite low but they increased when the catalysts were pre-reduced.A significant contribution of reverse water gas shift reaction accounted for the low values of H2/CO ratio.No coking was observed as shown by the reoxidation step performed after the catalytic reactions.The possible formation of nickel-iron alloy observed during the study of reducibility by hydrogen was invoked to account for the catalytic behavior.

  20. Alloy catalysts for fuel cell-based alcohol sensors

    Science.gov (United States)

    Ghavidel, Mohammadreza Zamanzad

    Direct ethanol fuel cells (DEFCs) are attractive from both economic and environmental standpoints for generating renewable energy and powering vehicles and portable electronic devices. There is a great interest recently in developing DEFC systems. The cost and performance of the DEFCs are mainly controlled by the Pt-base catalysts used at each electrode. In addition to energy conversion, DEFC technology is commonly employed in the fuel-cell based breath alcohol sensors (BrAS). BrAS is a device commonly used to measure blood alcohol concentration (BAC) and enforce drinking and driving laws. The BrAS is non-invasive and has a fast respond time. However, one of the most important drawback of the commercially available BrAS is the very high loading of Pt employed. One well-known and cost effective method to reduce the Pt loading is developing Pt-alloy catalysts. Recent studies have shown that Pt-transition metal alloy catalysts enhanced the electroactivity while decreasing the required loadings of the Pt catalysts. In this thesis, carbon supported Pt-Mn and Pt-Cu electrocatalysts were synthesized by different methods and the effects of heat treatment and structural modification on the ethanol oxidation reaction (EOR) activity, oxygen reduction reaction (ORR) activity and durability of these samples were thoroughly studied. Finally, the selected Pt-Mn and Pt-Cu samples with the highest EOR activity were examined in a prototype BrAS system and compared to the Pt/C and Pt 3Sn/C commercial electrocatalysts. Studies on the Pt-Mn catalysts produced with and without additives indicate that adding trisodium citrate (SC) to the impregnation solution improved the particle dispersion, decreased particle sizes and reduced the time required for heat treatment. Further studies show that the optimum weight ratio of SC to the metal loading in the impregnation solution was 2:1 and optimum results achieved at pH lower than 4. In addition, powder X-ray diffraction (XRD) analyses indicate

  1. An Analysis of Biogas Reforming Process on Ni/YSZ and Ni/SDC Catalysts

    Directory of Open Access Journals (Sweden)

    Janusz Szmyd

    2012-02-01

    Full Text Available The conversion of biogas to electricity presents an attractive niche application for fuel cells. Thus attempts have been made to use biogas as a fuel for high temperature fuel cell systems such as SOFC. Biogas can be converted to hydrogen-rich fuel in a reforming process. For hydrocarbon-based fuel, three types of fuel conversion can be considered in reforming reactions: an external reforming system, an indirect internal reforming system and a direct internal reforming system. High-temperature SOFC eliminates the need for an expensive external reforming system. The possibility of using internal reforming is one of the characteristics of high temperature fuel cells like SOFC. However, for high-temperature operation, thermal management of the SOFC system becomes an important issue. To properly carry out thermal management, both detailed modeling and numerical analyses of the phenomena occurring inside the SOFC system is required. In the present work, the process of reforming biogas on a Ni/YSZ and a Ni/SDC catalyst has been numerically and experimentally investigated. Measurements including different thermal boundary conditions, steam-to-carbon ratios and several different fuel compositions were taken. A numerical model containing methane/steam reforming reaction, dry reforming reaction and shift reaction has been proposed to predict the gas mixture composition at the outlet of the reformer. The results of the numerical computation were compared with experimental data and good agreement has been found. The results indicate the importance of combined, numerical and experimental studies in the design of SOFC reformers. The combined approach used leads to the successful prediction of the outlet gas composition for different modelling conditions.

  2. Hydrogen Generation from Catalytic Steam Reforming of Acetic Acid by Ni/Attapulgite Catalysts

    Directory of Open Access Journals (Sweden)

    Yishuang Wang

    2016-11-01

    Full Text Available In this research, catalytic steam reforming of acetic acid derived from the aqueous portion of bio-oil for hydrogen production was investigated using different Ni/ATC (Attapulgite Clay catalysts prepared by precipitation, impregnation and mechanical blending methods. The fresh and reduced catalysts were characterized by XRD, N2 adsorption–desorption, TEM and temperature program reduction (H2-TPR. The comprehensive results demonstrated that the interaction between active metallic Ni and ATC carrier was significantly improved in Ni/ATC catalyst prepared by precipitation method, from which the mean of Ni particle size was the smallest (~13 nm, resulting in the highest metal dispersion (7.5%. The catalytic performance of the catalysts was evaluated by the process of steam reforming of acetic acid in a fixed-bed reactor under atmospheric pressure at two different temperatures: 550 °C and 650 °C. The test results showed the Ni/ATC prepared by way of precipitation method (PM-Ni/ATC achieved the highest H2 yield of ~82% and a little lower acetic acid conversion efficiency of ~85% than that of Ni/ATC prepared by way of impregnation method (IM-Ni/ATC (~95%. In addition, the deactivation catalysts after reaction for 4 h were analyzed by XRD, TGA-DTG and TEM, which demonstrated the catalyst deactivation was not caused by the amount of carbon deposition, but owed to the significant agglomeration and sintering of Ni particles in the carrier.

  3. Acetaldehyde behavior over platinum based catalyst in hydrogen stream generated by ethanol reforming

    Energy Technology Data Exchange (ETDEWEB)

    de Lima, Adriana F.F. [Laboratorio de Catalise, Instituto Nacional de Tecnologia, Av. Venezuela 82/507, 20081-310 Rio de Janeiro, RJ (Brazil); Instituto de Quimica e INOG (Instituto Nacional de Oleo Gas), UERJ-CNPq, FAPERJ, Universidade do Estado do Rio de Janeiro, Rua Sao Francisco Xavier, 524, 20550-900 Rio de Janeiro, RJ (Brazil); Colman, Rita C. [Departamento de Engenharia Quimica e de Petroleo, Universidade Federal Fluminense, Av. Passos da Patria, 156/bl E/240, 24210-240 Niteroi, RJ (Brazil); Zotin, Fatima M.Z. [Instituto de Quimica e INOG (Instituto Nacional de Oleo Gas), UERJ-CNPq, FAPERJ, Universidade do Estado do Rio de Janeiro, Rua Sao Francisco Xavier, 524, 20550-900 Rio de Janeiro, RJ (Brazil); CETEM-MCT, Av. Pedro Calmon, 900, Cidade Universitaria, 21941-908 Rio de Janeiro, RJ (Brazil); Appel, Lucia G. [Laboratorio de Catalise, Instituto Nacional de Tecnologia, Av. Venezuela 82/507, 20081-310 Rio de Janeiro, RJ (Brazil)

    2010-12-15

    Due to the greenhouse effect, hydrogen production from bioethanol reforming is a very important subject in heterogeneous catalysis research. Pt based catalysts are employed in H{sub 2} purification processes and also as electrocatalysts of PEM (''Proton Exchange Membrane'') fuel cells. Hydrogen obtained from ethanol reforming may contain, as contaminants, acetaldehyde and small amounts of CO. This aldehyde can be decarbonylated on Pt based catalysts generating carbon monoxide and methane, rendering the hydrogen purification more challenging. Moreover, acetaldehyde might also change the electrocatalyst behavior. Therefore, this contribution aims at studying the acetaldehyde behavior in the presence of platinum based catalysts in hydrogen atmosphere. The Pt/SiO{sub 2}, Pt/USY catalysts and an electrocatalyst were characterized by n-butylamine, H{sub 2} and CO{sub 2} adsorption, ATG/DTG measurements and cyclohexane dehydrogenation reaction. It was observed that the acid-basic properties of the supports promote condensation reactions. When in contact with Pt based catalysts, acetaldehyde undergoes C-C and C=O bond scissions. The former occurs at a wide range of temperatures, whereas the latter only at low temperatures (<200 C). The C-C bond scission (decarbonylation) produces methane and CO. The C=O bond scission generates carbon residues on the catalyst as well as oxygen species, which in turn is able to eliminate CO from the catalytic surface. The data also show that decarbonylation is not a structure-sensitive reaction. (author)

  4. Ethanol steam reforming on Ni/Al-SBA-15 catalysts: Effect of the aluminium content

    Energy Technology Data Exchange (ETDEWEB)

    Lindo, M.; Vizcaino, A.J.; Calles, J.A.; Carrero, A. [Department of Chemical and Environmental Technology, Rey Juan Carlos University, c/ Tulipan s/n, 28933, Mostoles (Spain)

    2010-06-15

    A series of Ni catalysts supported on Al-SBA-15 mesoporous materials (Si/Al = 20, 60, 140, 240, {infinity}) was prepared and tested in ethanol steam reforming. The catalysts were characterized by XRD, H{sub 2}-TPR, NH{sub 3}-TPD, TEM, ICP-AES, {sup 27}Al-MAS-NMR and N{sub 2}-sorption measurements. It was found that the incorporation of Al atoms into SBA-15 structure is responsible for the formation of catalyst acid sites, an increase of the size of nickel species and stronger metal-support interaction between Ni and Al-SBA-15 carrier. Regarding ethanol steam reforming, catalysts with higher Al content keep ethanol conversion along time. However, Ni/Al-SBA-15 catalysts produce larger amounts of ethylene and coke, with slightly lower hydrogen selectivity than Ni/SBA-15. This is the consequence of ethanol dehydration in Ni/Al-SBA-15 acid sites, while ethanol dehydrogenation mechanism predominates in Ni/SBA-15 catalyst. (author)

  5. Improved catalytic performance of Ni catalysts for steam methane reforming in a micro-channel reactor

    Institute of Scientific and Technical Information of China (English)

    Bozhao Chu; Nian Zhang; Xuli Zhai; Xin Chen; Yi Cheng

    2014-01-01

    Milliseconds process to produce hydrogen by steam methane reforming (SMR) reaction, based on Ni catalyst rather than noble catalyst such as Pd, Rh or Ru, in micro-channel reactors has been paid more and more attentions in recent years. This work aimed to further improve the catalytic performance of nickel-based catalyst by the introduction of additives, i.e., MgO and FeO, prepared by impregnation method on the micro-channels made of metal-ceramic complex substrate. The prepared catalysts were tested in the same micro-channel reactor by switching the catalyst plates. The results showed that among the tested catalysts Ni-Mg catalyst had the highest activity, especially under harsh conditions, i.e., at high space velocity and/or low reaction temperature. Moreover, the catalyst activity and selectivity were stable during the 12 h on stream test even when the ratio of steam to carbon (S/C) was as low as 1.0. The addition of MgO promoted the active Ni species to have a good dispersion on the substrate, leading to a better catalytic performance for SMR reaction.

  6. Reduction of a Ni/Spinel Catalyst for Methane Reforming

    DEFF Research Database (Denmark)

    Kehres, Jan; Andreasen, Jens Wenzel; Fløystad, Jostein Bø

    2015-01-01

    A nickel/spinel (Ni/MgAl2O4) catalyst, w(Ni) = 22 wt%, was investigated in situ during reduction with wide angle X-ray scattering (WAXS) in a laboratory setup and with anomalous small angle X-ray scattering (ASAXS) at a synchrotron source. Complementary high resolution transmission electron micro...

  7. Temperature-programmed oxidation of coked noble metal catalysts after autothermal reforming of n-hexadecane

    Energy Technology Data Exchange (ETDEWEB)

    Kauppi, E.I.; Linnekoski, J.A.; Krause, A.O.I.; Veringa Niemelae, M.K. [Aalto University, School of Science and Technology, Department of Biotechnology and Chemical Technology, Research Group Industrial Chemistry, P.O. Box 16100, FI-00076 Aalto (Finland); Kaila, R.K. [VTT Technical Research Centre of Finland, Biologinkuja 7, Espoo, P.O. Box 1001, FI-02044 VTT (Finland)

    2010-08-15

    Autothermal reforming (ATR) of n-hexadecane was carried out on zirconia-supported mono- and bimetallic noble metal (Rh, Pt) catalysts at 600, 700, and 800 C. After ATR, the reactivity of coke deposits (2.8-9.9 wt%) on the catalysts was investigated by temperature-programmed oxidation (TPO). Analysis of the results obtained from ATR and TPO experiments at various temperatures and on the different catalysts gave information on the reaction conditions where the detrimental coke can be minimized and allows estimating the nature of carbon deposits. H{sub 2} production increased with temperature on the tested Rh-containing catalysts and the ZrO{sub 2} support, but decreased as a function of temperature on the Pt catalyst. The formation of coke was least at 800 C, evidently due to the intensifying reaction of carbon and steam with increasing temperature, as well as to the better activity of the catalysts. The amount of coke formed was highest at 700 C. Comparison of the TPO profiles obtained for the monometallic Rh and Pt catalysts with the bimetallic RhPt revealed differences in the nature of carbon deposits on their surface. At 600 C, the coke formed on the monometallic Rh and Pt catalysts was located mostly on the support, whereas on the bimetallic RhPt catalyst the formation of this type of coke was suppressed. The bimetallic RhPt catalyst also exhibited better tolerance toward coking at 700 C. Therefore, although the selectivity toward hydrogen was not related to the amount of coke formed, the deactivation patterns differed on the mono- and bimetallic catalysts. (author)

  8. 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.

  9. Removal of CO from reformed fuels by selective methanation over Ni-B-Zr-Oδ catalysts

    Institute of Scientific and Technical Information of China (English)

    Qihai Liu; Xinfa Dong; Yibing Song; Weiming Lin

    2009-01-01

    The Ni-B-Oδ and Ni-B-Zr-Oδcatalysts were prepared by the method of chemical reduction, and the deep removal of CO by selective methana-tion from the reformed fuels was performed over the as-prepared catalysts. The results showed that zirconium strongly influenced the activity and selectivity of the Ni-B-Zr-Oδ catalysts. Over the Ni-B-Oδ catalyst, the highest CO conversion obtained was only 24.32% under the experi-mental conditions studied. However, over the Ni-B-Zr-Oδ catalysts, the CO methanation conversion was higher than 90% when the temperature was increased to 220℃. Additionally, it was found that the Ni/B mole ratio also affected the performance of the Ni-B-Zr-Oδ catalysts. With the increase of the Ni/B mole ratio from 1.8 to 2.2, the CO methanation activity of the catalyst was improved. But when the Ni/B mole ratio was higher than 2.2, the performance of the catalyst for CO selective methanation decreased instead. Among all the catalysts, the Ni29B13Zr58Oδcatalyst investigated here exhibited the highest catalytic performance for the CO selective methanation, which was capable of reducing the CO outlet concentration to less than 40 ppm from the feed gases stream in the temperature range of 230-250℃, while the CO2 conversion was kept below 8% all along. Characterization of the Ni-B-Oδ and Ni-B-Zr-Oδ catalysts was provided by XRD, SEM, DSC, and XPS.

  10. Effect of RE-Doped and RE Quantity of Ni-Based Catalysts on CH4/CO2 Reforming Reaction

    Institute of Scientific and Technical Information of China (English)

    Yang Yifeng; Li Xiancai; Dai Chao; Wang Chunfeng; Chen Juanrong

    2004-01-01

    RE-doped Ni-based catalysts were prepared by sol-gel method.These catalysts were applied to the reaction of CO2 reforming CH4 to syngas.The studies reveal that RE-doped ( RE = La, Ce, Sm, Yb) Ni-based catalysts show higher catalytic activity than undoped Ni-based catalyst, and with the increasing of RE-doped quantity, the catalytic activity of catalysts exhibits regular changes.When RE-doped quantity is 0.2% ( molar ratio), the catalysts show the best catalytic activity.

  11. Potential of Ni supported on clinoptilolite catalysts for carbon dioxide reforming of methane

    Energy Technology Data Exchange (ETDEWEB)

    Nimwattanakul, Weetima; Luengnaruemitchai, Apanee; Jitkarnka, Sirirat [The Petroleum and Petrochemical College, Chulalongkorn University, Bangkok 10330 (Thailand)

    2006-01-15

    Carbon dioxide reforming of methane to synthesis gas has been investigated with Ni-supported clinoptilolite catalysts. The catalysts were prepared by using the incipient wetness impregnation method. The catalytic activity of Ni supported on clinoptilolite with varying Ni loadings was determined and the results showed that at 700{sup o}C, 8wt% Ni/clinoptilolite gave the highest activity. It exhibited not only the highest activity and selectivity but also remarkable stability. Moreover, both the activity and stability of this catalyst were observed to vary with the Zr content, exhibiting a maximum at a composition of 2% Zr. The amount of carbonaceous deposits on the spent catalysts was further investigated by temperature-programmed oxidation (TPO) and thermogravimetric analyzer (TGA) studies. (author)

  12. The Activity of Ni-Based Catalysts on Steam Reforming of Glycerol for Hydrogen Production

    Directory of Open Access Journals (Sweden)

    ALI SALEM EBSHISH

    2011-09-01

    Full Text Available Glycerol, the readily available bio renewable material, is effectively utilized for hydrogen production by a steam reforming reaction. The experiments were carried out in a continuous flow fixed-bed reactor over Nickel supported alumina catalysts under atmospheric pressure at 600°C and three hours reaction time. 5%wt Ni was loaded over γ-Al2O3 and effect of promoter metals such as Fe and Co over Ni/γ-Al2O3 catalytic systems were evaluated. The catalysts were characterized by BET surface area, XRD and SEM techniques. The activity results showed that the addition of Co enhanced the catalyst performance. The catalysts exhibited a good activity and selectivity to hydrogen.

  13. Steam reforming of glycerol for hydrogen production over supported nickel catalysts on alumina.

    Science.gov (United States)

    Choi, Ga Young; Kim, Young Chul; Moon, Dong Ju; Seo, Gon; Park, Nam Cook

    2013-01-01

    The experiment was carried out to produce hydrogen through steam reforming of glycerol over nano-sized Ni catalysts supported on alumina (Al2O3). The catalysts were characterized by BET surface area, metal dispersion, XRD, TPR, NH3-TPD and SEM. 15 wt% Ni/Al2O3 catalysts presented carbon nano fiber after the catalyst was used. However, when the Ni loading was higher than that of 15 wt%, the catalytic activity reduced, and the increase of the Ni particle size and the formation of graphitic carbon occurred. The Ni/SiO2(70)-Al2O3 with the high surface area and the small Ni particle size promoted the catalytic activity and could easily reduce from NiO to Ni, inhibiting the formation of NiAl2O4.

  14. Control of hydrocarbon content of a reforming gas by using a hydrogenation catalyst.

    Science.gov (United States)

    Inoue, Kenichiro; Kawamoto, Katsuya

    2010-01-01

    To control of hydrocarbon content in waste pyrolysis-gasification and reforming processes, the use of a hydrogenation catalyst was examined in a test system with a model gas. To reduce the concentration of benzene in the reforming gas, benzene was hydrogenated with a nickel catalyst. The catalyst is usually used to convert gas-phase unsaturated hydrocarbons to saturated hydrocarbons, and the benzene was converted to cyclohexane at a temperature range of about 130 to 180 degrees C in the presence of steam. However, the conversion to methane occurred at about 250 to 300 degrees C. Methane seems to be a useful conversion compound because it does not cohere as a light tar. Sometimes the reforming gas needs to be cooled for use as generator fuel. In this case, it is possible to avoid the tar cohesion if the benzene in the gas is converted to methane at about 300 degrees C after the reforming. Reduction of the efficiency of conversion to methane was not observed over a 60h reaction period. The lower hydrocarbons (ethylene, ethane, and propylene) were also converted to methane at about 300 degrees C. Conversion of benzene was also possible when other hydrocarbons were present at high concentrations.

  15. Polyol Synthesis of Cobalt–Copper Alloy Catalysts for Higher Alcohol Synthesis from Syngas

    DEFF Research Database (Denmark)

    Mendes, Laiza V.P.; Snider, Jonathan L.; Fleischman, Samuel D.

    2017-01-01

    Novel catalysts for the selective production of higher alcohols from syngas could offer improved pathways towards synthetic fuels and chemicals. Cobalt–copper alloy catalysts have shown promising results for this reaction. To improve control over particle properties, a liquid phase nanoparticle s...

  16. High Coke-Resistance Pt/Mg1-xNixO Catalyst for Dry Reforming of Methane.

    Science.gov (United States)

    Al-Doghachi, Faris A J; Islam, Aminul; Zainal, Zulkarnain; Saiman, Mohd Izham; Embong, Zaidi; Taufiq-Yap, Yun Hin

    2016-01-01

    A highly active and stable nano structured Pt/Mg1-xNixO catalysts was developed by a simple co-precipitation method. The obtained Pt/Mg1-xNixO catalyst exhibited cubic structure nanocatalyst with a size of 50-80 nm and realized CH4 and CO2 conversions as high as 98% at 900°C with excellent stability in the dry reforming of methane. The characterization of catalyst was performed using various kinds of analytical techniques including XRD, BET, XRF, TPR-H2, TGA, TEM, FESEM, FT-IR, and XPS analyses. Characterization of spent catalyst further confirms that Pt/Mg1-xNixO catalyst has high coke-resistance for dry reforming. Thus, the catalyst demonstrated in this study, offers a promising catalyst for resolving the dilemma between dispersion and reducibility of supported metal, as well as activity and stability during high temperature reactions.

  17. High Coke-Resistance Pt/Mg1-xNixO Catalyst for Dry Reforming of Methane.

    Directory of Open Access Journals (Sweden)

    Faris A J Al-Doghachi

    Full Text Available A highly active and stable nano structured Pt/Mg1-xNixO catalysts was developed by a simple co-precipitation method. The obtained Pt/Mg1-xNixO catalyst exhibited cubic structure nanocatalyst with a size of 50-80 nm and realized CH4 and CO2 conversions as high as 98% at 900°C with excellent stability in the dry reforming of methane. The characterization of catalyst was performed using various kinds of analytical techniques including XRD, BET, XRF, TPR-H2, TGA, TEM, FESEM, FT-IR, and XPS analyses. Characterization of spent catalyst further confirms that Pt/Mg1-xNixO catalyst has high coke-resistance for dry reforming. Thus, the catalyst demonstrated in this study, offers a promising catalyst for resolving the dilemma between dispersion and reducibility of supported metal, as well as activity and stability during high temperature reactions.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-01-15

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

  19. Alloyed Ni-Fe nanoparticles as catalysts for NH3 decomposition

    DEFF Research Database (Denmark)

    Simonsen, Søren Bredmose; Chakraborty, Debasish; Chorkendorff, Ib;

    2012-01-01

    A rational design approach was used to develop an alloyed Ni-Fe/Al2O3 catalyst for decomposition of ammonia. The dependence of the catalytic activity is tested as a function of the Ni-to-Fe ratio, the type of Ni-Fe alloy phase, the metal loading and the type of oxide support. In the tests with high...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-10-15

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

  1. Dolomite-Derived Ni-Based Catalysts with Fe Modification for Hydrogen Production via Auto-Thermal Reforming of Acetic Acid

    Directory of Open Access Journals (Sweden)

    Xinyan Zhong

    2016-06-01

    Full Text Available Bio-oil can be obtained via fast pyrolysis of biomass, and typically contains acetic acid (~30 mass %. The acetic acid has often been tested as a model compound for hydrogen production via reforming bio-oil, in which catalysts are a key factor for stable hydrogen production. However, deactivation of catalysts by coking and oxidation hinders the application of the reforming process. Dolomite-derived Ni-based catalysts with Fe additive, MgNi0.2Ca0.8−xFexO2±δ (x = 0–0.8, were successfully synthesized by the hydrothermal synthesis method, and then tested in auto-thermal reforming (ATR of acetic acid (AC. The MgNi0.2Ca0.5Fe0.3O2±δ catalyst performed a stable reactivity in ATR: the conversion of AC reached 100%, and the H2 yield remained stable around 2.6 mol-H2/mol-AC. The catalysts were characterized by X-ray diffraction (XRD, N2 physisorption, X-ray photoelectron spectra (XPS, H2-temperature-programmed reduction (TPR, inductively coupled plasma- atomic emission spectroscopy (ICP-AES and Thermogravimetry (TG; the results show that a periclase-like solid solution of Mg(Ni,FeO and lime were formed via the precursors of dolomite and hydrotalcite, and then transformed into Fe-rich Ni-Fe alloy with basic support of MgO-CaO after reduction. The stable Ni0 spices with basic support can explain the stability and resistance to coking during ATR of AC.

  2. Hydrogen production via reforming of biogas over nanostructured Ni/Y catalyst: Effect of ultrasound irradiation and Ni-content on catalyst properties and performance

    Energy Technology Data Exchange (ETDEWEB)

    Sharifi, Mahdi [Chemical Engineering Faculty, Sahand University of Technology, P.O. Box 51335-1996, Sahand New Town, Tabriz (Iran, Islamic Republic of); Reactor and Catalysis Research Center (RCRC), Sahand University of Technology, P.O. Box 51335-1996, Sahand New Town, Tabriz (Iran, Islamic Republic of); Haghighi, Mohammad, E-mail: haghighi@sut.ac.ir [Chemical Engineering Faculty, Sahand University of Technology, P.O. Box 51335-1996, Sahand New Town, Tabriz (Iran, Islamic Republic of); Reactor and Catalysis Research Center (RCRC), Sahand University of Technology, P.O. Box 51335-1996, Sahand New Town, Tabriz (Iran, Islamic Republic of); Abdollahifar, Mozaffar [Chemical Engineering Faculty, Sahand University of Technology, P.O. Box 51335-1996, Sahand New Town, Tabriz (Iran, Islamic Republic of); Reactor and Catalysis Research Center (RCRC), Sahand University of Technology, P.O. Box 51335-1996, Sahand New Town, Tabriz (Iran, Islamic Republic of)

    2014-12-15

    Highlights: • Synthesis of nanostructured Ni/Y catalyst by sonochemical and impregnation methods. • Enhancement of size distribution and active phase dispersion by employing sonochemical method. • Evaluation of biogas reforming over Ni/Y catalyst with different Ni-loadings. • Preparation of highly active and stable catalyst with low Ni content for biogas reforming. • Getting H{sub 2}/CO very close to equilibrium ratio by employing sonochemical method. - Abstract: The effect of ultrasound irradiation and various Ni-loadings on dispersion of active phase over zeolite Y were evaluated in biogas reforming for hydrogen production. X-ray diffraction, field emission scanning electron microscopy, energy dispersive X-ray, Brunauer–Emmett–Teller, Fourier transform infrared analysis and TEM analysis were employed to observe the characteristics of nanostructured catalysts. The characterizations implied that utilization of ultrasound irradiation enhanced catalyst physicochemical properties including high dispersion of Ni on support, smallest particles size and high catalyst surface area. The reforming reactions were carried out at GHSV = 24 l/g.h, P = 1 atm, CH{sub 4}/CO{sub 2} = 1 and temperature range of 550–850 °C. Activity test displayed that ultrasound irradiated Ni(5 wt.%)/Y had the best performance and the activity remained stable during 600 min. Furthermore, the proposed reaction mechanism showed that there are three major reaction channels in biogas reforming.

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

    Science.gov (United States)

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

    2013-12-01

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

  4. Sustainable hydrogen production by ethanol steam reforming using a partially reduced copper-nickel oxide catalyst.

    Science.gov (United States)

    Chen, Li-Chung; Cheng, Hongkui; Chiang, Chih-Wei; Lin, Shawn D

    2015-05-22

    Hydrogen production through the use of renewable raw materials and renewable energy is crucial for advancing its applications as an energy carrier. In this study, we fabricated a solid oxide solution of Cu and Ni within a confined pore space, followed by a partial reduction, to produce a highly efficient catalyst for ethanol steam reforming (ESR). At 300 °C, EtOH is completely converted, a H2 yield of approximately 5 mol per mol is achieved, and CO2 is the main carbon-containing product. This demonstrates that H2 production from bioethanol is an efficient and sustainable approach. Such a highly efficient ESR catalyst is attributed to the ability of the metal-oxide interface to facilitate the transformation of CHx adspecies from acetaldehyde decomposition into methoxy-like adspecies, which are reformed readily to produce H2 and consequently reduce CH4 formation.

  5. Ceria promotion over Ni-containing hydrotalcite-derived catalysts for CO2 methane reforming

    Directory of Open Access Journals (Sweden)

    Dębek Radosław

    2017-01-01

    Full Text Available The catalytic activity in dry methane reforming of hydrotalcite-derived catalysts with ceria and/or nickel species introduced into hydrotalcite interlayer spaces was examined. The prepared materials were characterized (XRF, XRD, FT-IR, H2-TPR and N2 sorption and subsequently tested in CO2 methane reforming at 550 °C. The obtained results showed that the incorporation of nickel species between hydrotalcite layers resulted in active catalyst with no sign of carbon deposition. Additionally, a beneficial effect of ceria promotion was observed. Ceria-promoted sample exhibited higher activity, stability and selectivity towards DRM, which may be explained by the formation of small Ni crystallites and prevention of the formation of inactive NiAl2O4 spinel phase.

  6. Development of Coke-tolerant Transition Metal Catalysts for Dry Reforming of Methane

    KAUST Repository

    Al-Sabban, Bedour E.

    2016-11-07

    Dry reforming of methane (DRM) is an attractive and promising process for the conversion of methane and carbon dioxide which are the most abundant carbon sources into valuable syngas. The produced syngas, which is a mixture of hydrogen and carbon monoxide, can be used as intermediates in the manufacture of numerous chemicals. To achieve high conversion, DRM reaction is operated at high temperatures (700-900 °C) that can cause major drawbacks of catalyst deactivation by carbon deposition, metal sintering or metal oxidation. Therefore, the primary goal is to develop a metal based catalyst for DRM that can completely suppress carbon formation by designing the catalyst composition. The strategy of this work was to synthesize Ni-based catalysts all of which prepared by homogeneous deposition precipitation method (HDP) to produce nanoparticles with narrow size distribution. In addition, control the reactivity of the metal by finely tuning the bimetallic composition and the reaction conditions in terms of reaction temperature and pressure. The highly endothermic dry reforming of methane proceeds via CH4 decomposition to leave surface carbon species, followed by removal of C with CO2-derived species to give CO. Tuning the reactivity of the active metal towards these reactions during DRM allows in principle the catalyst surface to remain active and clean without carbon deposition for a long-term. The initial attempt was to improve the resistance of Ni catalyst towards carbon deposition, therefore, a series of 5 wt.% bimetallic Ni9Pt1 were supported on various metal oxides (Al2O3, CeO2, and ZrO2). The addition of small amount of noble metal improved the stability of the catalyst compared to their monometallic Ni and Pt catalysts, but still high amount of carbon (> 0.1 wt.%) was formed after 24 h of the reaction. The obtained results showed that the catalytic performance, particle size and amount of deposited carbon depends on the nature of support. Among the tested

  7. Financial Crisis as a Catalyst of Legal Reforms : The Case of Asia

    OpenAIRE

    Kawai, Masahiro; Schmiegelow, Henrik

    2013-01-01

    This paper discusses how financial crises in emerging Asia and Japan worked as catalysts for legal reforms. The responses of six Asian countries with different legal histories to financial crises that posed similar challenges are of both legal and economic interest. We first provide a theoretical framework that focuses on law and economics. We then review the basic approaches adopted by the Asian countries affected by financial crises in 1997–1998 to bank and corporate restructuring and to ...

  8. Application of Cement Clinker as Ni-Catalyst Support for Glycerol Dry Reforming

    Directory of Open Access Journals (Sweden)

    Hua Chyn Lee

    2013-12-01

    Full Text Available The increase in biodiesel production inevitably yield plethora of glycerol. Therefore, glycerol has been touted as the most promising source for bio-syngas (mixture of H2 and CO production. Significantly, coking on nickel-based catalysts has been identified as a major deactivation factor in reforming technology. Indeed, coke-resistant catalyst development is essential to enhance syngas production. The current work develops cement clinker (comprised of 62.0% calcium oxide-supported nickel catalyst (with metal loadings of 5, 10, 15 and 20 wt% for glycerol dry reforming (CO2. Physicochemical characterization of the catalysts was performed using XRD, XRF, BET, TGA and FESEM-EDS techniques. Subsequently, reaction studies were conducted in a 7-mm ID fixed-bed stainless steel reactor at 1023 K with various CO2 partial pressures at constant weight-hourly space velocity (WHSV of 7.2×104 ml gcat-1 h-1. Gas compositions were determined using Agilent 3000 micro-gas chromatography (GC and Lancom III gas analyzer. Results obtained showed an increment of BET surface area up to 32-fold with Ni loading which was corroborated by FESEM images. Syngas (H2 and CO ratios of less than 2 were being produced at 1023 K. A closer scrutiny to the transient profile revealed that the presence of CO2 higher or lower than CGR 1:1 promotes the Boudouard reaction. © 2013 BCREC UNDIP. All rights reservedReceived: 30th May 2013; Revised: 27th August 2013; Accepted: 11st September 2013[How to Cite: Lee, H.C., Siew, W.K., Cheng, C.K. (2013. Preparation Application of Cement Clinker as Ni-Catalyst Support for Glycerol Dry Reforming. Bulletin of Chemical Reaction Engineering & Catalysis, 8 (2: 137-144. (doi:10.9767/bcrec.8.2.5023.137-144][Permalink/DOI: http://dx.doi.org/10.9767/bcrec.8.2.5023.137-144

  9. Rh-Ni and Rh-Co Catalysts for Autothermal Reforming of Gasoline

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Yeongyu; Lee, Daehyung; Kim, Yongmin; Lee, Jinhee; Nam, Sukwoo; Choi, Daeki; Yoon, Chang Won [Korea Institute of Science and Technology, Seoul (Korea, Republic of)

    2014-01-15

    Rh doped Ni and Co catalysts, Rh-M/CeO{sub 2}(20 wt %)-Al{sub 2}O{sub 3} (0.2 wt % of Rh; M = Ni or Co, 20 wt %) were synthesized to produce hydrogen via autothermal reforming (ATR) of commercial gasoline at 700 .deg. C under the conditions of a S/C ratio of 2.0, an O/C ratio of 0.84, and a gas hourly space velocity (GHSV) of 20,000 h{sup -1}. The Rh-Ni/CeO{sub 2}(20 wt %)-Al{sub 2}O{sub 3} catalyst (1) exhibited excellent activities, with H{sub 2} and (H{sub 2}+CO) yields of 2.04 and 2.58 mol/mol C, respectively. In addition, this catalyst proved to be highly stable over 100 h without catalyst deactivation, as evidenced by energy dispersive spectroscopy (EDX) and elemental analyses. Compared to 1, Rh-Co/CeO{sub 2}(20 wt %)-Al{sub 2}O{sub 3} catalyst (2) exhibited relatively low stability, and its activity decreased after 57 h. In line with this observation, elemental analyses confirmed that nearly no carbon species were formed at 1 while carbon deposits (10 wt %) were found at 2 following the reaction, which suggests that carbon coking is the main process for catalyst deactivation.

  10. Aqueous phase reforming of glycerol over nanosize Cu-Ni catalysts.

    Science.gov (United States)

    Kim, Ji Yeon; Kim, Seong Hak; Moon, Dong Ju; Kim, Jong Ho; Park, Nam Cook; Kim, Young Chul

    2013-01-01

    In this work, hydrogen production from glycerol by aqueous phase reforming (APR) is studied by using nanosize Ni-Cu catalysts supported on LaAlO3 perovskite in order to investigate the effects of the copper loading amount and the reaction conditions. Nanosize copper-promoted nickel-based catalysts were prepared by the precipitation method. The structure of the nanosize catalysts is characterized by XRD analysis. The surface area, morphology, dispersion and reducibility of the nanosize catalysts is examined by BET, TEM and TPR, respectively. It was found that 15Ni-5Cu/LaAlO3 catalyst showed the highest glycerol conversion and hydrogen selectivity. The highest activity found in the 15Ni-5Cu/LaAlO3 was attributed to it having the proper copper loading amount. It also has the lowest metal crystal size and the highest surface area, which have an effect on the catalytic activity and hydrogen selectivity. The 15Ni-5Cu/LaAlO3 catalyst showed the best performance for hydrogen production at a reaction temperature of 250 degrees C, a reaction pressure of 20 bar and a feed rate of 5 ml/h.

  11. First principles calculations and experimental insight into methane steam reforming over transition metal catalysts

    DEFF Research Database (Denmark)

    Jones, Glenn; Jakobsen, Jon Geest; Shim, Signe Sarah

    2008-01-01

    metal Surfaces to develop an overview of the steam reforming process catalyzed by a range of transition metal surfaces. By combining scaling relationships with thermodynamic and kinetic analysis, we show that it is possible to determine the reactivity trends of the pure metals for methane steam...... reforming. The reaction is found to be kinetically controlled by a methane dissociation step and a CO formation step, where the latter step is found to be dominant at lower temperatures. The particle size of the metal catalysts particles have been determined by transmission electron microscopy (TEM...... in situ TEM measurements under a hydrogen atmosphere. The overall agreement between theory and experiment (at 773 K, 1 bar pressure and 10% conversion) is found to be excellent with Ru and Rh being the most active pure transition metals for methane steam reforming, while Ni, Ir, Pt, and Pd...

  12. Development of biogas reforming Ni-La-Al catalysts for fuel cells

    Science.gov (United States)

    Benito, M.; García, S.; Ferreira-Aparicio, P.; Serrano, L. García; Daza, L.

    In this work, the results obtained for Ni-La-Al catalysts developed in our laboratory for biogas reforming are presented. The catalyst 5% Ni/5% La 2O 3-γ-Al 2O 3 has operated under kinetic control conditions for more than 40 h at 700 °C and feeding CH 4/CO 2 ratio 1/1, similar to the composition presented in biogas streams, being observed a stable behaviour. Reaction parameters studied to evaluate the catalyst activity were H 2/CO and CH 4/CO 2 conversion ratio obtained. On the basis of a CH 4 conversion of 6.5%, CH 4/CO 2 conversion ratio achieved 0.48 and H 2/CO ratio obtained was 0.43. By comparison of experimental results to equilibrium prediction for such conditions, is detectable a lower progress of reverse water gas shift reaction. This fact increases the H 2/CO ratio obtained and therefore the hydrogen production. The higher H 2/CO and a CH 4/CO 2 conversion ratio in comparison to CH 4 one close to equilibrium is due to the carbon deposits gasification which avoids catalyst deactivation. A thermodynamic analysis about the application of dry and combined methane reforming to hydrogen production for fuel cells application is presented. Data obtained by process simulation considering a Peng-Robinson thermodynamic model, allows optimizing process conditions depending on biogas composition.

  13. Bimetallic PtSn/C catalysts obtained via SOMC/M for glycerol steam reforming.

    Science.gov (United States)

    Pastor-Pérez, Laura; Merlo, Andrea; Buitrago-Sierra, Robison; Casella, Mónica; Sepúlveda-Escribano, Antonio

    2015-12-01

    A detailed study on the preparation of bimetallic PtSn/C catalysts using surface-controlled synthesis methods, and on their catalytic performance in the glycerol steam reforming reaction has been carried out. In order to obtain these well-defined bimetallic phases, techniques derived from Surface Organometallic Chemistry on Metals (SOMC/M) were used. The preparation process involved the reaction between an organometallic compound ((C4H9)4Sn) and a supported transition metal (Pt) in a H2 atmosphere. Catalysts with Sn/Pt atomic ratios of 0.2, 0.3, 0.5, and 0.7 were obtained, and characterized using several techniques: ICP, H2 chemisorption, TEM and XPS. These systems were tested in the glycerol steam reforming varying the reaction conditions (glycerol concentration and reaction temperature). The best performance was observed for the catalysts with the lowest tin contents (PtSn0.2/C and PtSn0.3/C). It was observed that the presence of tin increased the catalysts' stability when working under more severe reaction conditions.

  14. Hydrogen production via autothermal reforming of ethanol over noble metal catalysts supported on oxides

    Institute of Scientific and Technical Information of China (English)

    Hongqing Chen; Hao Yu; Yong Tang; Minqiang Pan; Guangxing Yang; Feng Peng; Hongjuan Wang; Jian Yang

    2009-01-01

    Hydrogen was produced over noble metal (Ir, Ru, Rh, Pd) catalysts supported on various oxides, including γ-Al2O3, CeO2, ZrO2 and La2O3, via the autothermai reforming reaction of ethanol (ATRE) and oxidative reforming reaction of ethanol (OSRE). The conversion of ethanol and selectivites for hydrogen and byproducts such as methane, ethylene and acetaldehyde were studied. It was found that lanthana alone possessed considerable activity for the ATRE reaction, which could be used as a functional support for ATRE catalysts. It was demonstrated that Ir/La2O3 prevented the formation of methane, and Rh/La2O3 encumbered the production of ethylene and acetaldehyde. ATRE reaction was carried out over La2O3-supported catalysts (Ir/La2O3) with good stability on stream, high conversion, and excellent hydrogen selectivity approaching thermodynamic limit under autothermal condition. Typically, 3.4 H2 molecules can be extracted from a pair of ethanol and water molecules over Ir(5wt%)/La2O3. The results presented in this paper indicate that Ir/La2O3 can be used as a promising catalyst for hydrogen production via ATRE reaction from renewable ethanol.

  15. Development and Commercial Application of Ultra-Low Pressure Naphtha Reforming Technology with Continuous Catalyst Regeneration

    Institute of Scientific and Technical Information of China (English)

    Ma Aizeng; Xu Youchun; Yang Dong; Zhang Xinkuan; Wang Jieguang

    2013-01-01

    The development history and major technological innovations of the ultra-low pressure naphtha reforming tech-nology with continuous catalyst regeneration in China were introduced. This technology had been adopted by the 1.0 Mt/a CCR unit at the Guangzhou Company. The appropriate catalyst was selected to meet the demand of the unit capacity, the feedstock, and the product slate. The design parameters, including the reaction pressure, the octane number of C5+ liquid product, the reaction temperature, the space velocity, the hydrogen/oil molar ratio, and the catalyst circulating rate, were chosen based on the study of process conditions and parameters. The commercial test results showed that the research oc-tane number of C5+ product reached 104 when the capacity of the CCR unit was 100% and 115% of the design value. The other technical targets attained or exceeded the expected value.

  16. Ce - promoted catalyst from hydrotalcites for CO2 reforming of methane: calcination temperature effect

    Directory of Open Access Journals (Sweden)

    Carlos Enrique Daza

    2012-01-01

    Full Text Available Ce-promoted Ni-catalysts from hydrotalcites were obtained. The effect of calcination temperature on the chemical and physical properties of the catalysts was studied. Several techniques were used to determine the chemical and physical characteristics of oxides. The apparent activation energies of reduction were determined. Catalytic experiments at 48 L g-1h-1 without pre-reduction in CO2 reforming of methane were performed. The spinel-like phase in these oxides was only formed at 1000 ºC. The reduction of Ni2+ in the oxides was clearly affected by the calcination temperature which was correlated with catalytic performance. The catalyst calcined at 700 ºC showed the greatest activity.

  17. The role of the oxidic support on the deactivation of Pt catalysts during the CO2 reforming of methane

    NARCIS (Netherlands)

    Bitter, J.H.; Hally, W.; Seshan, K.; Ommen, J.G. van; Lercher, J.A.

    1996-01-01

    Pt supported on y-Al2O3, TiO2 and ZrO2 are active catalysts for the CO2 reforming of methane to synthesis gas. The stability of the catalysts increased in the order Pt / y-Al2O3 < Pt / TiO2 < Pt / ZrO2. For all catalysts, the decrease in activity with time on stream is caused by carbon formation, wh

  18. Kinetics of Carbon Deposition on Hexaaluminate LaNiAl11O19 Catalyst During CO2 Reforming of Methane

    Institute of Scientific and Technical Information of China (English)

    Zhanlin Xu; Shuyong Jia; Lina Zhao; Yurong Ren; Yan Liu; Yingli Bi; Kaiji Zhen

    2003-01-01

    In this paper, the properties of carbon deposited on hexaaluminate LaNiAl11O19 catalyst were characterized by X-ray photoelectron spectroscopy (XPS), and in the meantime, the amount of carbon deposited on the catalyst, after both CH4 decomposition and CO2 reforming of CH4, was determined by means of thermogravimetric analysis (TGA), respectively. The rates of carbon deposited on the catalyst were also investigated and the apparent kinetic equation of CO2 reforming of CH4:carbon and the pressure ratio of CH4 and CO2.

  19. Microstructural characterization of Cu/ZnO/Al2O3 catalysts for the synthesis and steam reforming of methanol

    OpenAIRE

    2008-01-01

    Cu/ZnO/Al2O3 catalysts represent a versatile catalyst system for methanol chemistry, including the synthesis and steam reforming of methanol. Formally, the steam reforming of methanol is the reverse of methanol synthesis from CO2 and H2. In the present work a set of differently prepared Cu/ZnO/Al2O3 catalysts with a fixed composition of Cu/Zn/Al = 60:30:10 were investigated by in situ bulk techniques, X-ray diffraction, and X-ray absorption spectroscopy. Additionally, microscopic and morpholo...

  20. Glow Discharge Plasma-Assisted Preparation of Nickel-Based Catalyst for Carbon Dioxide Reforming of Methane

    Institute of Scientific and Technical Information of China (English)

    Fang Guo; Wei Chu; Jun-qiang Xu; Lin Zhong

    2008-01-01

    A plasma-assisted method was employed to prepare Ni/γ-Al2O3 catalyst for carbon dioxide reforming of methane reaction. The novel catalyst possessed higher activity and better coke-suppression performance than those of the conventional calcination catalyst. To achieve the same CH4 conversion, the conventional catalyst needed higher reaction temperature, about 50 ℃ higher than that of the N2 plasma-treated catalyst.After the evaluation test, the deactivation rate of the novel catalyst was 1.7%, compared with 15.2% for the conventional catalyst. Different from the characterization results of the calcined catalyst, a smaller average pore diameter and a higher specific surface area were obtained for the plasma-treated catalyst.The variations of the reduction peak temperatures and areas indicated that the catalyst reducibility was promoted by plasma assistance. The dispersion of nickel was also remarkably improved, which was helpful for controlling the ensemble size of metal atoms on the catalyst surface. The modification effect of plasmaassisted preparation on the surface property of alumina supported catalyst was speculated to account for the concentration increase of absorbed CO2. An enhancement of CO2 adsorption was propitious to the inhibition of carbon formation. The coke amount deposited on plasma treated catalyst was much smaller than that on the conventional catalyst.

  1. Non-catalytic recuperative reformer

    Energy Technology Data Exchange (ETDEWEB)

    Khinkis, Mark J.; Kozlov, Aleksandr P.; Kurek, Harry

    2015-12-22

    A non-catalytic recuperative reformer has a flue gas flow path for conducting hot flue gas from a thermal process and a reforming mixture flow path for conducting a reforming mixture. At least a portion of the reforming mixture flow path is embedded in the flue gas flow path to permit heat transfer from the hot flue gas to the reforming mixture. The reforming mixture flow path contains substantially no material commonly used as a catalyst for reforming hydrocarbon fuel (e.g., nickel oxide, platinum group elements or rhenium), but instead the reforming mixture is reformed into a higher calorific fuel via reactions due to the heat transfer and residence time. In a preferred embodiment, extended surfaces of metal material such as stainless steel or metal alloy that are high in nickel content are included within at least a portion of the reforming mixture flow path.

  2. Nickel and cobalt as active phase on supported zirconia catalysts for bio-ethanol reforming: Influence of the reaction mechanism on catalysts performance

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-09-15

    Steam reforming of ethanol for hydrogen production was investigated on Co/ZrO{sub 2} and Ni/ZrO{sub 2} catalysts promoted with lanthana. Catalysts were prepared by impregnation method and characterized by XRD and TPR. TPD-R experiments were also carried out to determine the role of active phase on reaction mechanism. The results suggest that adsorbed ethanol is dehydrogenated to acetaldehyde producing hydrogen. Then, the adsorbed acetaldehyde may evolve by different mechanisms, depending on the nature of active phase. On one hand, in cobalt-based catalyst, acetaldehyde could be reformed directly. By acetaldehyde thermal decomposition, methyl and formaldehyde groups are obtained. By coupling of methyl groups, ethane can be obtained. At medium temperature range, WGS reaction contribution is noteworthy. On the other hand, in nickel-based catalyst, acetone was detected in a higher temperature range as the main intermediate reaction product, which indicates that acetaldehyde is transformed into acetone by decarbonylation of acetaldehyde leading to H{sub 2} and CO{sub 2} formation. In addition, acetone can also be reformed to give both H{sub 2} and CO{sub 2}. Contrary to cobalt-based catalyst, ethylene was detected at intermediate range temperature which suggests that it was formed by ethanol dehydration reaction. Ethylene polymerization could easily explain coke formation, which must be avoided. Steam reforming reaction was studied at S/C ratio of 4.84 and 700 C, to verify the activity, selectivity and stability of the catalysts. Ethanol conversion reached 100% and catalysts were very stable for almost 50 h on stream. No significant differences were detected in both catalysts. Nevertheless, TPO experiments performed on used samples demonstrate a higher carbon production on nickel based catalyst that can be correlated to ethanol dehydration contribution on it reaction pathway. (author)

  3. Ni catalyst wash-coated on metal monolith with enhanced heat-transfer capability for steam reforming

    Science.gov (United States)

    Ryu, Jae-Hong; Lee, Kwan-Young; La, Howon; Kim, Hak-Joo; Yang, Jung-Il; Jung, Heon

    A commercial Ni-based catalyst is wash-coated on a monolith made of 50 μm-thick fecralloy plates. Compared with the same volume of coarsely powdered Ni catalysts, the monolith wash-coated Ni catalysts give higher methane conversion in the steam reforming reaction, especially at gas hourly space velocities (GHSV) higher than 28,000 h -1, and with no pressure drop. A higher conversion of the monolith catalyst is obtained, even though it contains a lower amount of active catalyst (3 g versus 17 g for a powdered catalyst), which indicates that the heat-transfer capability of the wash-coated Ni catalyst is significantly enhanced by the use of a metal monolith. The efficacy of the monolith catalyst is tested using a shell-and-tube type heat-exchanger reactor with 912 cm 3 of the monolith catalyst charged on to the tube side and hot combusted gas supplied to the shell side in a counter-current direction to the reactant flow. A methane conversion greater than 94% is obtained at a GHSV of 7300 h -1 and an average temperature of 640 °C. Nickel catalysts should first be reduced to become active for steam reforming. Doping a small amount (0.12 wt.%) of noble metal (Ru or Pt) in the commercial Ni catalyst renders the wash-coated catalyst as active as a pre-reduced Ni catalyst. Thus, noble metal-doped Ni appears useful for steam reforming without any pre-reduction procedure.

  4. Development of Fe-Ni/YSZ-GDC electro-catalysts for application as SOFC anodes. XRD and TPR characterization, and evaluation in ethanol steam reforming reaction

    Energy Technology Data Exchange (ETDEWEB)

    Paz Fiuza, Raigenis da; Silva, Marcos Aurelio da; Boaventura, Jaime Soares [UFBA, Salvador, Bahia (Brazil). Energy and Materials Science Group

    2010-07-01

    Electro-catalysts based on Fe-Ni alloys were prepared using physical mixture and modified Pechini methods; they were supported on a composite of Yttria Stabilized Zirconia (YSZ) and Gadolinia Doped Ceria (GDC). The composites had compositions of 35% metal load and 65% support (70% wt. YSZ and 30% wt. GDC mixture) (cermets). The samples were characterized by Temperature-Programmed Reduction (TPR) and X-Ray Diffraction (XRD) and evaluated in ethanol steam reforming at 650 C for six hours and in the temperature range 300 - 900 C. The XRD results showed that the bimetallic sample calcined at 800 C formed a mixed oxide (NiFe{sub 2}O{sub 4}) in spinel structure; after reducing the sample in hydrogen, Ni-Fe alloys were formed. The presence of Ni decreased the final reduction temperature of the NiFe{sub 2}O{sub 4} species. The addition of Fe to Ni anchored to YSZ-GDC increased the hydrogen production and inhibits the carbon deposition. The bimetallic 30Fe5Ni samples reached an ethanol conversion of about 95%, and a hydrogen yield up to 48% at 750 C. In general, the ethanol conversion and hydrogen production were independent of the metal content in the electro-catalyst. However, the substitution of Ni for Fe significantly reduced the carbon deposition on the electro-catalyst: 74, 31 and 9 wt. % in the 35Ni, 20Fe15Ni, and 30Fe5Ni samples, respectively. (orig.)

  5. Understanding of catalyst deactivation caused by sulfur poisoning and carbon deposition in steam reforming of liquid hydrocarbon fuels

    Science.gov (United States)

    Xie, Chao

    2011-12-01

    The present work was conducted to develop a better understanding on the catalyst deactivation in steam reforming of sulfur-containing liquid hydrocarbon fuels for hydrogen production. Steam reforming of Norpar13 (a liquid hydrocarbon fuel from Exxon Mobile) without and with sulfur was performed on various metal catalysts (Rh, Ru, Pt, Pd, and Ni) supported on different materials (Al2O3, CeO2, SiO2, MgO, and CeO2- Al2O3). A number of characterization techniques were applied to study the physicochemical properties of these catalysts before and after the reactions. Especially, X-ray absorption near edge structure (XANES) spectroscopy was intensively used to investigate the nature of sulfur and carbon species in the used catalysts to reveal the catalyst deactivation mechanism. Among the tested noble metal catalysts (Rh, Ru, Pt, and Pd), Rh catalyst is the most sulfur tolerant. Al2O3 and CeO2 are much better than SiO2 and MgO as the supports for the Rh catalyst to reform sulfur-containing hydrocarbons. The good sulfur tolerance of Rh/Al2O3 can be attributed to the acidic nature of the Al2O3 support and its small Rh crystallites (1-3 nm) as these characteristics facilitate the formation of electron-deficient Rh particles with high sulfur tolerance. The good catalytic performance of Rh/CeO2 in the presence of sulfur can be ascribed to the promotion effect of CeO2 on carbon gasification, which significantly reduced the carbon deposition on the Rh/CeO2catalyst. Steam reforming of Norpar13 in the absence and presence of sulfur was further carried out over CeO2-Al2O3 supported monometallic Ni and Rh and bimetallic Rh-Ni catalysts at 550 and 800 °C. Both monometallic catalysts rapidly deactivated at 550 °C, iv and showed poor sulfur tolerance. Although ineffective for the Ni catalyst, increasing the temperature to 800 °C dramatically improved the sulfur tolerance of the Rh catalyst. Sulfur K-edge XANES revealed that metal sulfide and organic sulfide are the dominant sulfur

  6. Miniature fuel cell with monolithically fabricated Si electrodes - Alloy catalyst formation -

    Science.gov (United States)

    Ogura, Daiki; Suzuki, Takahiro; Katayama, Noboru; Dowaki, Kiyoshi; Hayase, Masanori

    2013-12-01

    A novel Pd-Pt catalyst formation process was proposed for reduction of Pt usage. In our miniature fuel cells, porous Pt was used as the catalyst, and the Pt usage was quite high. To reduce the Pt usage, we have attempted to deposit Pt on porous Pd by galvanic replacement, and relatively large output was demonstrated. In this study, in order to reduce more Pt usage and explore the alloy catalyst formation process, atomic layer deposition by UPD-SLRR (Under Potential Deposition - Surface Limited Redox Replacement) was applied to the Pd-Pt catalyst formation. The new process was verified at each process steps by EDS elemental analysis, and the expected spectra were obtained. Prototype cells were constructed by the new process, and cell output was raised to 420mW/cm2 by the Pd-Pt catalyst from 125mW/cm2 with Pd catalyst.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-07-15

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

  8. Catalytic activity of cobalt and cerium catalysts supported on calcium hydroxyapatite in ethanol steam reforming

    Directory of Open Access Journals (Sweden)

    Dobosz Justyna

    2016-09-01

    Full Text Available In this paper, Co,Ce/Ca10(PO46(OH2 catalysts with various cobalt loadings for steam reforming of ethanol (SRE were prepared by microwave-assisted hydrothermal and sol-gel methods, and characterized by XRD, TEM, TPR-H2, N2 adsorption-desorption measurements and cyclohexanol (CHOL decomposition tests. High ethanol conversion (close to 100% was obtained for the catalysts prepared by both methods but these ones prepared under hydrothermal conditions (HAp-H ensured higher hydrogen yield (3.49 mol H2/mol C2H5OH as well as higher amount of hydrogen formed (up to 70% under reaction conditions. The superior performance of 5Co,10Ce/HAp-H catalyst is thought to be due to a combination of factors, including increased reducibility and oxygen mobility, higher density of basic sites on its surface, and improved textural properties. The results also show a significant effect of cobalt loading on catalysts efficiency in hydrogen production: the higher H2 yield exhibit catalysts with lower cobalt content, regardless of the used synthesis method.

  9. Identification and quantification of Sn-based species in trimetallic Pt-Sn-In/Al2O3-Cl naphtha-reforming catalysts

    Science.gov (United States)

    Jumas, Jean-Claude; Sougrati, Moulay Tahar; Olivier-Fourcade, Josette; Jahel, Ali; Avenier, Priscilla; Lacombe, Sylvie

    2013-04-01

    Trimetallic Pt/Al2O3SnIn-Cl naphtha-reforming catalysts were prepared via co-precipitation route. Platinum and chlorine were introduced by the incipient wetness technique on the alumina support already doped with about 0.3 %wt of Sn to obtain about 0.3 %wt of Pt and 1.5 %wt of Cl. For the same Pt, Sn and Cl composition, indium loading ranged from 0.06 to 0.6 wt.%. The obtained catalysts were investigated by 119Sn Mössbauer spectroscopy between 95 and 300 K. Two Sn(IV), Sn(II) and Sn(0) environments have been identified and well characterized by their hyperfine parameters. The Lamb-Mössbauer factors have been determined for each environment and found to be 0.53, 0.27 and 0.31 for Sn(IV), Sn(II) and Sn(0) respectively. The addition of indium has been found to favour the formation of PtxSn alloys. 119Sn Mössbauer spectroscopy results show that addition of even small amount of In (0.06 wt.%) leads to the formation of a Pt3Sn alloy. At higher indium loadings, higher amounts of PtxSn alloys of almost equal Pt and Sn atomic concentrations were detected. The increasing formation of PtxSn alloys with higher indium loading is in good correlation with a decrease of catalyst's overall conversion and selectivity to C1 and C3-C4 paraffins and increase of isomerization selectivity.

  10. Nanostructured Platinum Alloys for Use as Catalyst Materials

    Science.gov (United States)

    Hays, Charles C. (Inventor); Narayan, Sri R. (Inventor)

    2015-01-01

    A series of binary and ternary Pt-alloys, that promote the important reactions for catalysis at an alloy surface; oxygen reduction, hydrogen oxidation, and hydrogen and oxygen evolution. The first two of these reactions are essential when applying the alloy for use in a PEMFC.

  11. Characterization of La-promoted Ni/Al2O3 catalysts for hydrogen production from glycerol dry reforming

    Institute of Scientific and Technical Information of China (English)

    Kah; Weng; Siew; Hua; Chyn; Lee; Jolius; Gimbun; Chin; Kui; Cheng

    2014-01-01

    In the current paper, dry(CO2)-reforming of glycerol, a new reforming route, was carried out over alumina(Al2O3)-supported, non-promoted and lanthanum-promoted nickel(Ni) catalysts. Both sets of catalysts were synthesized via a wet co-impregnation procedure. Physicochemical characterization of the catalysts showed that the promoted catalyst possessed smaller metal crystallite size, hence higher metal dispersion compared to the virgin Ni/Al2O3catalyst. This was also corroborated by the surface images captured by the FESEM analysis. From temperature-programmed calcination analysis, the derivative weight profiles revealed two peaks, which represent a water elimination peak at a temperature range of 373 to 473 K followed by nickel nitrate decomposition from 473 to 573 K. In addition, BET surface area measurements gave 85.0 m2 g-1for the non-promoted Ni catalyst, whilst the promoted catalysts showed an average of 1% to 6% improvement depending on the La loadings. Significantly, reaction studies at 873 K showed that glycerol dry reforming successfully produced H2. The 2%La-Ni/Al2O3catalyst, which possessed the largest BET surface area, gave an optimum H2generation(9.70%) at a glycerol conversion of 24.5%.

  12. Reforming of Ethanol to Produce Hydrogen over PtRuMg/ZrO2 Catalyst

    Directory of Open Access Journals (Sweden)

    Josh Y. Z. Chiou

    2012-01-01

    Full Text Available A modified PtRu/ZrO2 catalyst with Mg is evaluated for the oxidative steam reforming of ethanol (OSRE and the steam reforming of ethanol (SRE. In order to understand the variation in the reaction mechanism on OSRE and SRE, further analysis of both fresh and used catalyst is concentrated on for TEM, TG, Raman, and TPR characterization. The results show that the OSRE reaction requires a higher temperature (∼390°C to achieve 100% ethanol conversion than the SRE reaction (∼2500°C. The distribution of CO is minor for both reactions (< 5% for OSRE, < 1% for SRE. This demonstrates that the water gas shift (WGS reaction is an important side-reaction in the reforming of ethanol to produce H2 and CO2. A comparison of the temperature of WGS (WGS shows it is lower for the SRE reaction (WGS∼250°C for SRE, ~340°C for OSRE.

  13. Methane decomposition on Ni-Cu alloyed Raney-type catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Cunha, A.F.; Orfao, J.J.M.; Figueiredo, J.L. [Laboratorio de Catalise e Materiais, Laboratorio Associado LSRE/LCM, Departamento de Engenharia Quimica, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal)

    2009-06-15

    In the present work, we report on the performance of Ni-Cu alloyed Raney-type catalysts for the production of hydrogen by catalytic methane decomposition. The activity of the catalysts was assessed by comparing the experimental conversions with the calculated equilibrium conversions for each set of experimental conditions. The stability of the catalysts was assessed by comparing the maximum conversions with the conversions at the end of 5 h tests. Comparison with monometallic Ni Raney-type catalytic systems shows that Cu addition significantly improves catalyst stability. Excellent results were obtained when the Ni-Cu Raney-type system was thermally treated in situ at 600 C, as a result of incipient alloy formation. (author)

  14. Dry re-forming of methane to synthesis gas over lignite semicokes catalyst at high pressure

    Directory of Open Access Journals (Sweden)

    Fengbo Guo

    2016-11-01

    Full Text Available Dry re-forming of methane has been carried out in a high temperature–pressure reactor at different pressures, using Hongce lignite semicokes catalyst. The results show that CH4 and CO2 conversions are decreased as the reaction pressure increased, but both of them kept basically stable when the reaction pressure is between 0.3 and 1 MPa. The comparison shows that the effects of the temperature and the flow of reactant gas on dry re-forming of methane are consistent with between high pressure and atmospheric pressure. The ratio of CO/H2 decreased as the ratio of CH4/CO2 increased, yet the value of CO/H2 is always more than 1 at different pressures. Hongce lignite semicokes catalyst is characterized by FTIR, XRD, SEM and BET, and the analysis results reveled that the physical specific adsorption peak of CO2 at 2350 cm−1 is strengthened significantly at different pressures, the micropore area and volume of Hongce lignite semicokes reduced form 40.2 m2  g−1 and 0.019 cm3  g−1 to 34.9 m2  g−1 and 0.017 cm3  g−1, respectively. Hongce lignite semicokes catalyst exhibited better activity and stability within 0.3–1 MPa range.

  15. Sulfur Tolerant Magnesium Nickel Silicate Catalyst for Reforming of Biomass Gasification Products to Syngas

    Directory of Open Access Journals (Sweden)

    Scott L. Swartz

    2012-04-01

    Full Text Available Magnesium nickel silicate (MNS has been investigated as a catalyst to convert tars and light hydrocarbons to syngas (CO and H2 by steam reforming and CO2 reforming in the presence of H2S for biomass gasification process at NexTech Materials. It was observed that complete CH4 conversion could be achieved on MNS catalyst granules at 800–900 °C and a space velocity of 24,000 mL/g/h in a simulated biomass gasification stream. Addition of 10–20 ppm H2S to the feed had no apparent impact on CH4 conversion. The MNS-washcoated monolith also showed high activities in converting methane, light hydrocarbons and tar to syngas. A 1200 h test without deactivation was achieved on the MNS washcoated monolith in the presence of H2S and/or NH3, two common impurities in gasified biomass. The results indicate that the MNS material is a promising catalyst for removal of tar and light hydrocarbons from biomass gasified gases, enabling efficient use of biomass to produce power, liquid fuels and valuable chemicals.

  16. PREPARATION, CHARACTERIZATION AND CATALYTIC ACTIVITY TEST OF CoMo/ZnO CATALYST ON ETHANOL CONVERSION USING STEAM REFORMING METHOD

    Directory of Open Access Journals (Sweden)

    Wega Trisunaryanti

    2010-06-01

    Full Text Available Preparation, characterization and catalytic activity test of CoMo/ZnO catalyst for steam reforming of ethanol have been investigated. The catalysts preparation was carried out by impregnation of Co and/or Mo onto ZnO sample. Water excess was used in ethanol feed for steam reforming process under mol ratio of ethanol:water (1:10. Characterizations of catalysts were conducted by analysis of metal content using Atomic Absorption Spectroscopy (AAS. Determination of catalysts acidity was conducted by gravimetric method of adsorption of pyridine base. Catalytic activity test on ethanol conversion using steam reforming method was conducted in a semi-flow reactor system, at a temperature of 400 oC, for 1.5 h under N2 flow rate of 10 mL/min. Gas product was analyzed by gas chromatograph with TCD system. The results of catalysts characterizations showed that the impregnation of Co and/or Mo metals on ZnO sample increased its acidity and specific surface area. The content of Co in Co/ZnO and CoMo/ZnO catalysts was 1.14 and 0.49 wt%. The Mo content in CoMo/ZnO catalyst was 0.36 wt%. The catalytic activity test result on ethanol conversion showed that the ZnO, Co/ZnO, and CoMo/ZnO catalysts produced gas fraction of 16.73, 28.53, and 35.53 wt%, respectively. The coke production of ZnO, Co/ZnO, and CoMo/ZnO catalysts was 0.86, 0.24, and 0.08 wt%, respectively. The gas products consisted mainly of hydrogen.   Keywords: CoMo/ZnO catalyst, steam reforming, ethanol

  17. A Novel Ultrafine Ru-B Amorphous Alloy Catalyst for Glucose Hydrogenation to Sorbitol

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    An ultrafine Ru-B amorphous alloy catalyst was prepared by chemical reduction with KBH4 in aqueous solution, which exhibited perfect selectivity to sorbitol (~100%) and very high activity during the liquid phase glucose hydrogenation, much higher than the corresponding crystallized Ru-B, the pure Ru powder, and Raney Ni catalysts. The correlation of the catalytic activity to both the structural and surface electronic characteristics was discussed briefly.

  18. Amorphous Nickel Based Alloy Catalysts and Magnetically Stabilized Bed Hydrogenation Technology

    Institute of Scientific and Technical Information of China (English)

    MuXuhong; ZongBaoning; 等

    2002-01-01

    Amorphous nickel based alloy catalysts(denoted as the SRNA series catalysts)were prepared via rapid quenching method followed by alkali leaching and other activation procedures.The physicochemical characterizations show that nickel,the active component in these catalysts,exists in the amorphous state,and the catalyst particles possess many nanosized voids leading to large surface area(the highest is 145m2/g).The evaluation results in some model reactions show that the SRNA series catalysts have 2 to 4 times higher activity and selectivity than conventional Raney Ni catalyst for the hydrogenation of compounds with unsatur-ated functional groups.At present,the SRNA series catalysts have been successfully used in hydrogenation of glucose,hydrogenation of pharmaceutical intermediates and purification of caprolactam.In order to use these catalysts efficiently,a magnetically stabilized bed(MSB) technology has been developed by combining the ferromagnetic property of the catalyst with the good mass transfer characteristics of MSB.The demonstration unit of MSB hydrogenation technology has been set up and has kept running for 2800 hours.The results show that,after running 2800 hours,the catalyst still retained good activity; meanwhile,the hydrogenation effi-ciency had been improved 10 times in comparison with the traditional CSTR process.

  19. High efficiency hydrogen production from biomass waste via low temperature gasification-reforming technology with catalyst materials

    Energy Technology Data Exchange (ETDEWEB)

    Kawamoto, K.; Wu, W.; Kuramochi, H. [National Inst. for Environmental Studies, Tsukuba (Japan)

    2007-07-01

    A pyrolytic gasification and reforming process for waste wood and municipal solid wastes was presented. The system was capable of using catalysts at a relatively low temperature. Details of the basic gasification and reforming system were provided in this paper, as well as tests conducted to validate the system's design. Four nickel-based catalysts were tested, 2 of which also contained calcium oxide (CaO) or potassium oxide (K{sub 2}O). Experiments were conducted with a series of 2 reactor systems comprised of a gasifier and a reformer equipped with a catalyst bed. Results of the experiments suggested that hydrogen could be obtained at concentration levels of up to 50 per cent with gas and 40 mol/kg-feedstock with waste wood. Use of steam-reforming Ni catalysts promoted hydrogen production, but also decreased operating temperatures by approximately 200 degrees K. Tar concentrations were reduced by 50 per cent when a catalyst was used. The combined use of Ni and CaO improved hydrogen recovery performance and reduced by-product production. It was concluded that while dioxins formed during the pyrolysis process, their formation decreased with increases in temperature thermal residence time, as well as when catalysts for decomposition were used. 2 refs., 3 tabs., 11 figs.

  20. Steam reforming of methane over Pt/Rh based wire mesh catalyst in single channel reformer for small scale syngas production

    DEFF Research Database (Denmark)

    Sigurdsson, Haftor Örn; Kær, Søren Knudsen

    2012-01-01

    of a catalytic parallel plate type heat exchanger (CPHE) reformer stack, where coated Pt/Rh based wire mesh is used as a catalyst. Heat is supplied to the endothermic reaction with infrared electric heaters. All the experiments were performed under atmospheric pressure and at stable operating conditions....... The following parameters are considered in the experiment: catalyst temperature, gas hourly space velocity (GHSV) and steam to carbon ratio (S/C). The catalyst was tested at temperatures between 600 and 900°C, S/C ratios between 2 and 5 and GHSV between 319 and 2201 1/h. The experimental results are used...

  1. Methanol Reforming over Cobalt Catalysts Prepared from Fumarate Precursors: TPD Investigation

    Directory of Open Access Journals (Sweden)

    Eftichia Papadopoulou

    2016-02-01

    Full Text Available Temperature-programmed desorption (TPD was employed to investigate adsorption characteristics of CH3OH, H2O, H2, CO2 and CO on cobalt-manganese oxide catalysts prepared through mixed Co-Mn fumarate precursors either by pyrolysis or oxidation and oxidation/reduction pretreatment. Pyrolysis temperature and Co/Mn ratio were the variable synthesis parameters. Adsorption of methanol, water and CO2 was carried out at room temperature. Adsorption of H2 and H2O was carried out at 25 and 300 °C. Adsorption of CO was carried out at 25 and 150 °C. The goal of the work was to gain insight on the observed differences in the performance of the aforementioned catalysts in methanol steam reforming. TPD results indicated that activity differences are mostly related to variation in the number density of active sites, which are able to adsorb and decompose methanol.

  2. Pure silica SBA-15 supported Cu-Ni catalysts for hydrogen production by ethanol steam reforming

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-07-01

    Cu-Ni/SBA-15 supported catalysts prepared by the incipient wetness impregnation method were tested in the ethanol steam reforming reaction for hydrogen production. The effect of reaction temperature and metal loading was studied in order to maximize the hydrogen selectivity and the CO{sub 2}/CO{sub x} molar ratio. The best catalytic performance was achieved at 600 C with a catalyst containing 2 and 7 wt% of copper and nickel, respectively. In addition, two catalysts were prepared by the method of direct insertion of Ni and Cu ions as precursors in the initial stage of the synthesis. XRD, TEM, N{sub 2} adsorption and ICP-AES results evidenced that SBA-15 materials with long range hexagonal ordering could be successfully synthesized in the presence of copper and nickel salts with the (Cu+Ni) contents around 4-6 wt%. However, lower hydrogen selectivity and together with ethanol and water conversions were observed with catalysts prepared by direct synthesis in comparison with those prepared by incipient wetness impregnation method. (authors)

  3. Carbon Deposition Onto Ni-Based Catalysts for Combined Steam/CO2 Reforming of Methane.

    Science.gov (United States)

    Li, Peng; Park, Yoon Hwa; Moon, Dong Ju; Park, Nam Cook; Kim, Young Chul

    2016-02-01

    The present study was performed to suppress carbon deposition by Ce and Fe onto Ni-based catalysts in combined steam/CO2 reforming of methane (CSCRM), which is a process for producing synthesis gas (H2:CO = 2:1) for gas-to-liquids (GTL). The catalytic reaction was evaluated at 900 degrees C and 20 bar with a reactant feed ratio CH4:CO2:H20:Ar = 1:0.8:1.3:1 and gas hourly space velocity GHSV = 25,000 h(-1). The Ce and Fe modified Ni/gamma-A120, catalyst was characterized by BET surface area analysis, X-ray diffraction (XRD), H2 temperature-programmed reduction (TPR), H2 chemisorption, CO2 temperature-programmed desorption (TPD) and SEM. Ce- and Fe-modified Ni/Al2O3 catalysts exhibited remarkable activity and stability during the CSCRM over the course of 50 hours. It suggested that the Ni(12)-Ce(5)-Fe(5)/Al2O3 catalyst shows highly dispersed Ni particles with strong metal-to-support interaction (SMSI) as well as excellent catalytic activity.

  4. Promotion effect of cobalt-based catalyst with rare earth for the ethanol steam reforming

    Science.gov (United States)

    Chiou, Josh Y. Z.; Chen, Ya-Ping; Yu, Shen-Wei; Wang, Chen-Bin

    2013-12-01

    Catalytic performance of ethanol steam reforming (ESR) was investigated on praseodymium (Pr) modified ceria-supported cobalt oxide catalyst. The ceria-supported cobalt oxide (Ce-Co) catalyst was prepared by co-precipitation-oxidation (CPO) method, and the doped Pr (5 and 10 wt% loading) catalysts (Pr5-Ce-Co and Pr10-Ce-Co) were prepared by incipient wetness impregnation method. The reduction pretreatment under 250 and 400 °C (H250 and H400) was also studied. All samples were characterized by XRD, TPR and TEM. Catalytic performance of ESR was tested from 250 to 500 °C in a fixed-bed reactor. The doping of Pr into the ceria lattice has significantly promoted the activity and reduced the coke formation. The products distribution also can be influenced by the different reduction pretreatment. The Pr10-Ce-Co-H400 sample is a preferential ESR catalyst, where the hydrogen distribution approaches 73% at 475 °C with less amounts (< 2%) of CO and CH4.

  5. Development of biogas reforming Ni-La-Al catalysts for fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Benito, M.; Garcia, S.; Ferreira-Aparicio, P.; Serrano, L. Garcia; Daza, L. [Instituto de Catalisis y Petroleoquimica (CSIC), C/ Marie Curie 2, Campus Cantoblanco, 28049 Madrid (Spain)

    2007-06-10

    In this work, the results obtained for Ni-La-Al catalysts developed in our laboratory for biogas reforming are presented. The catalyst 5% Ni/5% La{sub 2}O{sub 3}-{gamma}-Al{sub 2}O{sub 3} has operated under kinetic control conditions for more than 40 h at 700 C and feeding CH{sub 4}/CO{sub 2} ratio 1/1, similar to the composition presented in biogas streams, being observed a stable behaviour. Reaction parameters studied to evaluate the catalyst activity were H{sub 2}/CO and CH{sub 4}/CO{sub 2} conversion ratio obtained. On the basis of a CH{sub 4} conversion of 6.5%, CH{sub 4}/CO{sub 2} conversion ratio achieved 0.48 and H{sub 2}/CO ratio obtained was 0.43. By comparison of experimental results to equilibrium prediction for such conditions, is detectable a lower progress of reverse water gas shift reaction. This fact increases the H{sub 2}/CO ratio obtained and therefore the hydrogen production. The higher H{sub 2}/CO and a CH{sub 4}/CO{sub 2} conversion ratio in comparison to CH{sub 4} one close to equilibrium is due to the carbon deposits gasification which avoids catalyst deactivation. A thermodynamic analysis about the application of dry and combined methane reforming to hydrogen production for fuel cells application is presented. Data obtained by process simulation considering a Peng-Robinson thermodynamic model, allows optimizing process conditions depending on biogas composition. (author)

  6. 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.

  7. Controllable Deposition of Alloy Clusters or Nanoparticles Catalysts on Carbon Surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, K.; Ando, Y.; Su, D.; Adzic, R.

    2011-08-15

    We describe a simple method for controllably depositing Pt-Ru alloy nanoparticles on carbon surfaces that is mediated by Pb or Cu adlayers undergoing underpotential deposition and stripping during Pt and Ru codeposition at diffusion-limiting currents. The amount of surface Pt atoms deposited largely reflects the number of potential cycles causing the deposition and stripping of the metal adlayer at underpotentials, the metal species used as a mediator, and the scan rate of the potential cycles. We employed electrochemical methanol oxidation to gain information on the catalyst's activities. The catalysts with large amounts of surface Pt atoms have relatively high methanol-oxidation activity. Catalysts prepared using this method enhance methanol-oxidation activity per electrode surface area, while maintaining catalytic activity per surface Pt atom; thus, the amount of Pt is reduced in comparison with conventional methanol-oxidation catalysts. The method is suitable for efficient synthesizing various bimetallic catalysts.

  8. Amorphous Nickel Based Alloy Catalysts and Magnetically Stabilized Bed Hydrogenation Technology

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Amorphous nickel based alloy catalysts (denoted as the SRNA series catalysts) were prepared viarapid quenching method followed by alkali leaching and other activation procedures. The physicochemicalcharacterizations show that nickel, the active component in these catalysts, exists in the amorphous state, andthe catalyst particles possess many nanosized voids leading to large surface area (the highest is 145m2/g). Theevaluation results in some model reactions show that the SRNA series catalysts have 2 to 4 times higheractivity and selectivity than conventional Raney Ni catalyst for the hydrogenation of compounds with unsatur-ated functional groups. At present, the SRNA series catalysts have been successfully used in hydrogenation ofglucose, hydrogenation of pharmaceutical intermediates and purification of caprolactam. In order to use thesecatalysts efficiently, a magnetically stabilized bed (MSB) technology has been developed by combining theferromagnetic property of the catalyst with the good mass transfer characteristics of MSB. The demonstrationunit of MSB hydrogenation technology has been set up and has kept running for 2800 hours. The results showthat, after running 2800 hours, the catalyst still retained good activity; meanwhile, the hydrogenation effi-ciency had been improved 10 times in comparison with the traditional CSTR process.

  9. Amorphous Nickel Based Alloy Catalysts and Magnetically Stabilized Bed Hydrogenation Technology

    Institute of Scientific and Technical Information of China (English)

    Mu Xuhong; Zong Baoning; Meng Xiangkun; Min Enze

    2002-01-01

    Amorphous nickel based alloy catalysts (denoted as the SRNAseries catalysts) were prepared viarapid quenching method followed by alkali leaching and other activation procedures. The physicochemicalcharacterizations show that nickel, the active component in these catalysts, exists in the amorphous state, andthe catalyst particles possess many nanosized voids leading to large surface area (the highest is 145m2/g). Theevaluation results in some model reactions show that the SRNA series catalysts have 2 to 4 times higheractivity and selectivity than conventional Raney Ni catalyst for the hydrogenation of compounds with unsatur-ated functional groups. At present, the SRNA series catalysts have been successfully used in hydrogenation ofglucose, hydrogenation of pharmaceutical intermediates and purification of caprolactam. In order to use thesecatalysts efficiently, a magnetically stabilized bed (MSB) technology has been developed by combining theferromagnetic property of the catalyst with the good mass transfer characteristics of MSB. The demonstrationunit of MSB hydrogenation technology has been set up and has kept running for 2800 hours. The results showthat, after running 2800 hours, the catalyst still retained good activity; meanwhile, the hydrogenation effi-ciency had been improved 10 times in comparison with the traditional CSTR process.

  10. Steam reforming of glycerol into hydrogen over nano-size Ni-based hydrotalcite-like catalysts.

    Science.gov (United States)

    Hur, Eun; Moon, Dong Ju

    2011-08-01

    Steam reforming (SR) of glycerol for the production of hydrogen was investigated over the nano-sized Ni-based catalysts. The Ni-based catalysts were prepared by solid phase crystallization and impregnation methods, and characterized by N2 physisorption, CO chemisorption, XRD, SEM, and TEM techniques. The Ni/gamma-Al2O3 catalyst showed higher conversion and H2 selectivity. However, it was slowly deactivated due to the carbon formation on the surface of catalyst and the sintering. It was found that the Ni based hydrotalcite-like catalyst (spc-Ni/MgAl) showed higher catalytic activity to prevent carbon formation than Ni/gamma-Al2O3 catalyst in the SR of glycerol.

  11. H2 production with low CO selectivity from photocatalytic reforming of glucose on metal/TiO2 catalysts

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    H2 with low CO concentration is produced via photocatalytic reforming of glucose (as a representative of biomass component) on metal/TiO2 catalyst (metals: Pt, Rh, Ru, Ir, Au, Ni, Cu). It is shown that the loaded metals generally enhance the rate of H2 production, while they depress the CO selectivity. Both H2 production and CO selectivity are strongly dependent on the kind of deposited metals on TiO2. For example, Rh/TiO2 catalyst is found to be most active for H2 production while with the most extremely low CO concentration from the photocatalytic reforming of glucose.

  12. Short Review: Cu Catalyst for Autothermal Reforming Methanol for Hydrogen Production

    Directory of Open Access Journals (Sweden)

    Ho-Shing Wu

    2012-06-01

    Full Text Available Hydrogen is a promising alternative energy sources, hydrogen can be used in fuel cell applications to pro-ducing electrical energy and water as byproduct. Therefore, fuel cell is a simple application and environ-mentally friendly oriented technology. Recent years various methods have been conducted to produce hy-drogen. Those methods are derived from various sources such as methanol, ethanol, gasoline, hydrocarbons. This article presents a brief review a parameter process of that affects in autothermal reforming methanol use Cu-based catalysts for production of hydrogen. Copyright © 2012 BCREC UNDIP. All rights reserved.Received: 3rd January 2012; Revised: 23rd February 2012; Accepted: 28th February 2012[How to Cite: H.S. Wu, and D. Lesmana. (2012. Short Review: Cu Catalyst for Autothermal Reforming Methanol for Hydrogen Production. Bulletin of Chemical Reaction Engineering & Catalysis, 7 (1: 27-42. doi:10.9767/bcrec.7.1.1284.27-42][How to Link / DOI: http://dx.doi.org/10.9767/bcrec.7.1.1284.27-42 ] | View in 

  13. Autothermal reforming of dimethyl ether with CGO-based precious metal catalysts

    Science.gov (United States)

    Choi, Seunghyeon; Bae, Joongmyeon

    2016-03-01

    In this paper, we investigated the DME ATR reaction with different types of precious metal (Pt, Rh, Ru)-supported CGO catalysts. We also evaluated the reaction characteristics of DME ATR reaction by modifying certain reforming conditions, including the temperature, the amount of air and water, and the flow rate. The Ru-added CGO catalyst showed the best performance in DME ATR. The operating condition that produced the greatest effect on conversion efficiency was temperature; however the amounts of steam and air were also important with regard to conversion efficiency and the reaction heat. In case higher GHSV conditions the methane yields are increased. To maximize conversion efficiency with thermal neutral operating conditions, we suggest an SCR of 1.5, OCR of 0.45, over temperature of 700 °C, and a GHSV of less than 20,000/h. Under harsh conditions, such as low temperature and high GHSV, the methane yield increases. Therefore, the high temperature DME ATR reaction seems to consist of two main steps: the DME decomposition to methane and the methane autothermal reforming reaction.

  14. Skeletal Amorphous Nickel Based Alloy Catalysts and Magnetically Stabilized Bed Hydrogenation Technology

    Institute of Scientific and Technical Information of China (English)

    Min Enze

    2004-01-01

    Looking toward 21 century, smaller, cleaner and more energy-efficient technology will be an important trend in the development of chemical industry. In light of the new process requirements,a number of technology breakthroughs have occurred. One of these discoveries, the magnetically stabilized bed (MSB), has been proven a powerful process for intensification. Since its initial research in the late 1980's at Research Institute of Petroleum Processing (RIPP), the MSB technology and related catalytic material have matured rapidly through an intensive research and engineering program, primarily focused on its scaling-up.In this paper, we report the discovery of a novel skeletal amorphous nickel-based alloy and its use in magnetically stabilized bed (MSB). Amorphous alloys are new kinds of catalytic materials with short-range order but long-range disorder structure. In comparison with Raney Ni, the skeletal amorphous nickel-based alloy has an increasingly higher activity in the hydrogenation of reactive groups and compounds including nitro, nitrile, olefin, acetylene, aromatics, etc. Up to now, the amorphous nickel based alloy catalysts, SRNA series catalyst, one with high Ni ratio have been commercially manufactured more than four year. The new SRNA catalyst has been successfully implemented for hydrogenation applications in slurry reactor at Balin Petrochemical, SINOPEC.SRNA catalyst with further improvement in catalytic activity and stability raise its relative stability to 2~4 times of that of conventional catalyst. In the course of the long-cycle operation of SRNA-4 the excellent catalyst activity and stability can bring about such advantage as low reaction temperature, good selectivity and low catalyst resumption.Magnetically stabilized bed (MSB), a fluidized bed of magnetizable particles by applying a spatially uniform and time-invariant magnetic field oriented axially relative to the fluidizing fluid flow, had many advantages such as the low pressure drop and

  15. Liquid and Gaseous Fuel from Waste Plastics by Sequential Pyrolysis and Catalytic Reforming Processes over Indonesian Natural Zeolite Catalysts

    Directory of Open Access Journals (Sweden)

    Mochamad Syamsiro

    2014-08-01

    Full Text Available In this study, the performance of several differently treated natural zeolites in a sequential pyrolysis and catalytic reforming of plastic materials i.e. polypropylene (PP and polystyrene (PS were investigated. The experiments were carried out on two stage reactor using semi-batch system. The samples were degraded at 500°C in the pyrolysis reactor and then reformed at 450°C in the catalytic reformer. The results show that the mordenite-type natural zeolites could be used as efficient catalysts for the conversion of PP and PS into liquid and gaseous fuel. The treatment of natural zeolites in HCl solution showed an increase of the surface area and the Si/Al ratio while nickel impregnation increased the activity of catalyst. As a result, liquid product was reduced while gaseous product was increased. For PP, the fraction of gasoline (C5-C12 increased in the presence of catalysts. Natural zeolite catalysts could also be used to decrease the heavy oil fraction (>C20. The gaseous products were found that propene was dominated in all conditions. For PS, propane and propene were the main components of gases in the presence of nickel impregnated natural zeolite catalyst. Propene was dominated in pyrolysis over natural zeolite catalyst. The high quality of gaseous product can be used as a fuel either for driving gas engines or for dual-fuel diesel engine.

  16. Efficient hydrogen production from ethanol and glycerol by vapour-phase reforming processes with new cobalt-based catalysts.

    Science.gov (United States)

    Pereira, Evandro Brum; de la Piscina, Pilar Ramírez; Homs, Narcís

    2011-02-01

    The aim of this study was to investigate biohydrogen production from biofuel-reforming processes using new multi-component bulk-type cobalt-based catalysts. The addition of different components to improve the catalytic performance was studied. Monometallic cobalt catalyst and catalysts containing Ru (ca. 1%) and/or Na (ca. 0.5%) were characterized and tested in the 623-673 K temperature range in ethanol steam reforming (ESR) with a steam/carbon ratio (S/C) of 3. The catalysts showed a high performance for hydrogen production and, except for H(2) and CO(2), only small amounts of by-products were obtained, depending on the temperature and the catalyst used. The catalyst containing both Ru and Na (Co-Ru(Na)) showed the best catalytic behavior in ESR. It operated stably for at least 12 days under cycles of oxidative steam reforming of glycerol/ethanol mixtures (S/C=2) and activation under O(2).

  17. Pt-Re-Sn/Al{sub 2}O{sub 3} trimetallic catalysts for naphtha reforming processes without presulfiding step

    Energy Technology Data Exchange (ETDEWEB)

    Mazzieri, V.A.; Grau, J.M.; Vera, C.R.; Yori, J.C.; Parera, J.M.; Pieck, C.L. [Instituto de Investigaciones en Catalisis y Petroquimica, INCAPE, FIQ-UNL, CONICET, Santiago del Estero 2654, 3000 Santa Fe (Argentina)

    2005-12-12

    The n-heptane reforming and the cyclopentane hydrogenolysis reactions over noble metal monometallic catalysts (0.3% Pt), bimetallic catalysts (0.3% Pt, x% Re, x=0.1, 0.3, 0.9 and 2.0, sulfided) and trimetallic catalysts (0.3% Pt, 0.3% Re, y% Sn, y=0.1, 0.3, 0.6 and 0.9, unsulfided) were studied. The metal function was supported over a chlorided {gamma}-alumina that provided the acid function. The reforming of n-heptane was performed at 450{sup o}C, molar ratio H{sub 2}/n-C{sub 7}=4 and WHSV=7.3 while the hydrogenolysis of cyclopentane was performed at 350{sup o}C, H{sub 2}/CP=20 and WHSV=2.4. The sulfided 0.3Pt-0.3Re catalyst (with 0.06% S) was found to be the best performing bimetallic one. It had a great stability, typical of this kind of catalysts, and also produced a reformate with a high iso-heptanes/toluene ratio. This is advantageous for fulfilling the current environmental regulations that limit the amount of aromatic hydrocarbons in reformulated gasolines. The best trimetallic catalyst was 0.3Pt-0.3Re-0.6Sn which had a similar activity and selectivity as sulfided 0.3Pt-0.3Re, though it displayed a higher stability and a lower hydrogenolysis activity, without the need of presulfidation. Tin affected the metal and acid functions of the catalyst simultaneously and inhibited them to such different degrees that a very convenient metal/acid activity ratio was obtained, resulting in an improvement of the activity, selectivity and stability of the catalysts. It can be concluded that it is possible to prepare trimetallic naphtha reforming catalysts of the Pt-Re-Sn kind with a better performance than conventional sulfided Pt-Re catalysts and with the additional advantage that they do not need complicated sulfiding pretreatments. This simplifies the commercial operation of the reformer unit and enables the application of this catalyst to continuously operated processes.

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

    Institute of Scientific and Technical Information of China (English)

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

    2014-01-01

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

  19. Steam reforming of ethanol over Ni-based catalysts: Effect of feed composition on catalyst stability

    DEFF Research Database (Denmark)

    Trane-Restrup, Rasmus; Dahl, Søren; Jensen, Anker Degn

    2014-01-01

    In this work the effects of steam-to-carbon ratio (S/C), and addition of H2 or O2 to the feed on the product yields and carbon deposition in the steam reforming (SR) of ethanol over Ni/MgAl2O4, Ni/Ce0.6Zr0.4O2, and Ni/CeO2 at 600 °C have been investigated. Increasing the S/C-ratio from 1.6 to 8.......3 over Ni/MgAl2O4 increased conversion of ethanol as well as the yield of H2, while the carbon deposition and yield of hydrocarbons decreased. Oxygen addition at S/C-ratio of 6 over Ni/MgAl2O4, Ni/Ce0.6Zr0.4O2, and Ni/CeO2 increased conversion, decreased the yield of hydrocarbons, and led to a decrease...... in the carbon deposition. Carbon deposition was almost eliminated over Ni/MgAl2O4 and Ni/Ce0.6Zr0.4O2 at an O/C-ratio of roughly 0.8 or higher. The penalty of adding O2 was a decrease in the yield of H2 from 70% at O/C = 0 to 50% at O/C = 0.8–1.A 90 h test at O/C = 1.1, S/C = 6, and 600 °C over Ni/MgAl2O4...

  20. Zirconia supported catalysts for bioethanol steam reforming: Effect of active phase and zirconia structure

    Energy Technology Data Exchange (ETDEWEB)

    Benito, M.; Padilla, R.; Rodriguez, L.; Sanz, J.L.; Daza, L. [Instituto de Catalisis y Petroleoquimica (CSIC), C/ Marie Curie 2, Campus Cantoblanco, 28049 Madrid (Spain)

    2007-06-10

    Three new catalysts have been prepared in order to study the active phase influence in ethanol steam reforming reaction. Nickel, cobalt and copper were the active phases selected and were supported on zirconia with monoclinic and tetragonal structure, respectively. To characterize the behaviour of the catalysts in reaction conditions a study of catalytic activity with temperature was performed. The highest activity values were obtained at 973 K where nickel and cobalt based catalysts achieved an ethanol conversion of 100% and a selectivity to hydrogen close to 70%. Nickel supported on tetragonal zirconia exhibited the highest hydrogen production efficiency, higher than 4.5 mol H{sub 2}/mol EtOH fed. The influence of steam/carbon (S/C) ratio on product distribution was another parameter studied between the range 3.2-6.5. Nickel supported on tetragonal zirconia at S/C = 3.2 operated at 973 K without by-product production such as ethylene or acetaldehyde. In order to consider a further application in an ethanol processor, a long-term reaction experiment was performed at 973 K, S/C = 3.2 and atmospheric pressure. After 60 h, nickel supported on tetragonal zirconia exhibited high stability and selectivity to hydrogen production. (author)

  1. Numerical simulation of effect of catalyst wire-mesh pressure drop characteristics on flow distribution in catalytic parallel plate steam reformer

    DEFF Research Database (Denmark)

    Sigurdsson, Haftor Örn; Kær, Søren Knudsen

    2012-01-01

    , is considered to investigate the effect of catalyst wire-mesh pressure drop characteristics on flow distribution in the CPHE reformer. Flow distribution in a CPHE reformer is rarely uniform due to inlet and exhaust manifold design. Poorly-designed manifolds may lead to severe flow maldistribution, flow reversal...... in some of the CPHE reformer channels and increased overall pressure drop. Excessive flow maldistribution can significantly reduce the CPHE reformer performance. Detailed three-dimensional models are used to investigate the flow distribution at three different catalyst wire-mesh pressure drop coefficients......Steam reforming of hydrocarbons using a catalytic plate-type-heat-exchanger (CPHE) reformer is an attractive method of producing hydrogen for a fuel cell-based micro combined-heat-and-power system. In this study the flow distribution in a CPHE reformer, which uses a coated wire-mesh catalyst...

  2. Numerical simulation of effect of catalyst wire-mesh pressure drop characteristics on flow distribution in catalytic parallel plate steam reformer

    DEFF Research Database (Denmark)

    Sigurdsson, Haftor Örn; Kær, Søren Knudsen

    2012-01-01

    Steam reforming of hydrocarbons using a catalytic plate-type-heat-exchanger (CPHE) reformer is an attractive method of producing hydrogen for a fuel cell-based micro combined-heat-and-power system. In this study the flow distribution in a CPHE reformer, which uses a coated wire-mesh catalyst...

  3. Pt Monolayer Shell on Nitrided Alloy Core—A Path to Highly Stable Oxygen Reduction Catalyst

    Directory of Open Access Journals (Sweden)

    Jue Hu

    2015-07-01

    Full Text Available The inadequate activity and stability of Pt as a cathode catalyst under the severe operation conditions are the critical problems facing the application of the proton exchange membrane fuel cell (PEMFC. Here we report on a novel route to synthesize highly active and stable oxygen reduction catalysts by depositing Pt monolayer on a nitrided alloy core. The prepared PtMLPdNiN/C catalyst retains 89% of the initial electrochemical surface area after 50,000 cycles between potentials 0.6 and 1.0 V. By correlating electron energy-loss spectroscopy and X-ray absorption spectroscopy analyses with electrochemical measurements, we found that the significant improvement of stability of the PtMLPdNiN/C catalyst is caused by nitrogen doping while reducing the total precious metal loading.

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

    Institute of Scientific and Technical Information of China (English)

    Fereshteh Meshkani; Mehran Rezaei

    2011-01-01

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

  5. Influence of Gold on Ce-Zr-Co Fluorite-Type Mixed Oxide Catalysts for Ethanol Steam Reforming

    Directory of Open Access Journals (Sweden)

    Véronique Pitchon

    2012-02-01

    Full Text Available The effect of gold presence on carbon monoxide oxidation and ethanol steam reforming catalytic behavior of two Ce-Zr-Co mixed oxides catalysts with a constant Co charge and different Ce/Zr ratios was investigated. The Ce-Zr-Co mixed oxides were obtained by the pseudo sol-gel like method, based on metallic propionates polymerization and thermal decomposition, whereas the gold-supported Ce-Zr-Co mixed oxides catalysts were prepared using the direct anionic exchange. The catalysts were characterized using XRD, TPR, and EDXS-TEM. The presence of Au in doped Ce-Zr-Co oxide catalyst decreases the temperature necessary to reduce the cobalt and the cerium loaded in the catalyst and favors a different reaction pathway, improving the acetaldehyde route by ethanol dehydrogenation, instead of the ethylene route by ethanol dehydration or methane re-adsorption, thus increasing the catalytic activity and selectivity into hydrogen.

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

    Energy Technology Data Exchange (ETDEWEB)

    Srinivas, S.T.; Song, C.

    1999-07-01

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

  7. Steam reforming of tar model compound using Pd catalyst on alumina tube.

    Science.gov (United States)

    Nisamaneenate, Jurarat; Atong, Duangduen; Sricharoenchaikul, Viboon

    2012-12-01

    Gasification processing of biomass as a renewable energy source generates tar in the product gas. Tar leads to foul-up of the process equipment by corrosion and deposit formation. Catalytic elimination of tars is a crucial step to improve fuel gas quality from the process. In this study, a palladium catalyst on alumina (Pd/Al2O3) was used in steam reforming of benzene as a biomass gasification tar model compound. The reaction was carried out in a laboratory-scale tube reactor made of stainless steel to study the effect of reaction temperature, catalyst loading, quantity of palladium catalyst tubes, steam to carbon ratio (S/C), and residence time on catalytic performance and stability. Pd/Al2O3 showed high efficiency ofbenzene decomposition and enhanced the formation of fuel gas. Hydrogen and carbon conversions increased with reaction temperature. Although the benzene concentration increased from 2000 to 5000 mg/l, the catalytic performance at 600 degrees C and 800 degrees C was similar. 1.0 wt% Pd/Al2O3 showed excellent catalytic activity with the highest hydrogen and carbon conversions of 83% and 81%, respectively at 800 degrees C. This result is attributed to the smooth surface of the palladium, as noted from scanning electron microscopy imaging. An S/C of 2 provided the highest conversion. The addition of catalyst from four and seven tubes did not result in any great difference in terms of benzene cracking efficiency. The fourth cyclic usage of 1.0 wt% Pd/Al2O3 exhibited a higher conversion than that of 0.5 wt%.

  8. High Coke-Resistance Pt/Mg1-xNixO Catalyst for Dry Reforming of Methane: e0145862

    National Research Council Canada - National Science Library

    Faris A J Al-Doghachi; Aminul Islam; Zulkarnain Zainal; Mohd Izham Saiman; Zaidi Embong; Yun Hin Taufiq-Yap

    2016-01-01

    ...°C with excellent stability in the dry reforming of methane. The characterization of catalyst was performed using various kinds of analytical techniques including XRD, BET, XRF, TPR-H2, TGA, TEM, FESEM, FT-IR, and XPS analyses...

  9. High Coke-Resistance Pt/Mg1-xNixO Catalyst for Dry Reforming of Methane

    National Research Council Canada - National Science Library

    Al-Doghachi, Faris A J; Islam, Aminul; Zainal, Zulkarnain; Saiman, Mohd Izham; Embong, Zaidi; Taufiq-Yap, Yun Hin

    2016-01-01

    ...°C with excellent stability in the dry reforming of methane. The characterization of catalyst was performed using various kinds of analytical techniques including XRD, BET, XRF, TPR-H2, TGA, TEM, FESEM, FT-IR, and XPS analyses...

  10. Highly selective bimetallic Pt-Cu/Mg(Al)O catalysts for the aqueous-phase reforming of glycerol

    NARCIS (Netherlands)

    Boga, D.A.; Oord, R.; Beale, A.M.; Chung, Y.M.; Bruijnincx, P.C.A.; Weckhuysen, B.M.

    2013-01-01

    Monometallic Pt and bimetallic Pt-Cu catalysts supported on Mg(Al)O mixed oxides, obtained by calcination of the corresponding layered double hydroxides (LDHs), were prepared and tested in the aqueous-phase reforming (APR) of glycerol. The effect of the Mg/Al ratio and calcination temperature of the

  11. Hierarchical Pd-Sn alloy nanosheet dendrites: an economical and highly active catalyst for ethanol electrooxidation.

    Science.gov (United States)

    Ding, Liang-Xin; Wang, An-Liang; Ou, Yan-Nan; Li, Qi; Guo, Rui; Zhao, Wen-Xia; Tong, Ye-Xiang; Li, Gao-Ren

    2013-01-01

    Hierarchical alloy nanosheet dendrites (ANSDs) are highly favorable for superior catalytic performance and efficient utilization of catalyst because of the special characteristics of alloys, nanosheets, and dendritic nanostructures. In this paper, we demonstrate for the first time a facile and efficient electrodeposition approach for the controllable synthesis of Pd-Sn ANSDs with high surface area. These synthesized Pd-Sn ANSDs exhibit high electrocatalytic activity and superior long-term cycle stability toward ethanol oxidation in alkaline media. The enhanced electrocataytic activity of Pd-Sn ANSDs may be attributed to Pd-Sn alloys, nanosheet dendrite induced promotional effect, large number of active sites on dendrite surface, large surface area, and good electrical contact with the base electrode. Because of the simple implement and high flexibility, the proposed approach can be considered as a general and powerful strategy to synthesize the alloy electrocatalysts with high surface areas and open dendritic nanostructures.

  12. Ethanol steam reforming on Ni/Al{sub 2}O{sub 3} catalysts: Effect of Mg addition

    Energy Technology Data Exchange (ETDEWEB)

    Vizcaino, A.J.; Carrero, A.; Calles, J.A. [Department of Chemical and Environmental Technology, ESCET, Universidad Rey Juan Carlos, C/Tulipan s/n, 28933 Mostoles, Madrid (Spain); Arena, P.; Baronetti, G.; Laborde, M.A.; Amadeo, N. [Chemical Engineering Department, School of Engineering, Universidad de Buenos Aires, Pabellon de Industrias, Ciudad Universitaria, 1428 Buenos Aires (Argentina)

    2008-07-15

    Ethanol steam reforming is an interesting alternative for hydrogen production since ethanol can be renewably obtained. Use of lamellar double hydroxides (LDHs) as precursors of nickel catalysts leads to highly dispersed metal particles in an aluminium structure. In this sense, a Ni(II)Al(III) catalyst was synthesized from a LDH precursor and tested in ethanol steam reforming. Although this catalyst presents high stability, acidity of alumina promotes carbon deposition from ethylene through ethanol dehydration. For this reason, in order to neutralize acid sites, a series of catalysts was prepared by Mg addition to LDH precursors varying Mg/Ni ratio. The effect of Mg/Ni ratio in the catalyst on coke formation during ethanol steam reforming was studied, resulting in significant reduction of the amount of deposited carbon for Mg/Ni ratio higher than 0.1. Moreover, Mg addition increases the catalytic activity due to lower ethylene formation, which competes with ethanol for the same Ni active sites. (author)

  13. Low-temperature, vapor-liquid-solid, laterally grown silicon films using alloyed catalysts

    Science.gov (United States)

    LeBoeuf, Jerome L.; Brodusch, Nicolas; Gauvin, Raynald; Quitoriano, Nathaniel J.

    2014-12-01

    Using amorphous oxide templates known as micro-crucibles which confine a vapor-liquid-solid catalyst to a specific geometry, two-dimensional silicon thin-films of a single orientation have been grown laterally over an amorphous substrate and defects within crystals have been necked out. The vapor-liquid-solid catalysts consisted nominally of 99% gold with 1% titanium, chromium, or aluminum, and each alloy affected the processing of micro-crucibles and growth within them significantly. It was found that chromium additions inhibited the catalytic effect of the gold catalysts, titanium changed the morphology of the catalyst during processing and aluminum stabilized a potential third phase in the gold-silicon system upon cooling. Two mechanisms for growing undesired nanowires were identified both of which hindered the VLS film growth, fast silane cracking rates and poor gold etching, which left gold nanoparticles near the gold-vapor interface. To reduce the silane cracking rates, growth was done at a lower temperature while an engineered heat and deposition profile helped to reduce NWs caused by the second mechanism. Through experimenting with catalyst compositions, the fundamental mechanisms which produce concentration gradients across the gold-silicon alloy within a given micro-crucible have been proposed. Using the postulated mechanisms, micro-crucibles were designed which promote high-quality, single crystal growth of semiconductors.

  14. Enhanced catalytic behavior of Ni alloys in steam methane reforming

    Science.gov (United States)

    Yoon, Yeongpil; Kim, Hanmi; Lee, Jaichan

    2017-08-01

    The dissociation process of methane on Ni and Ni alloys are investigated by density functional theory (DFT) in terms of catalytic efficiency and carbon deposition. Examining the dissociation to CH3, CH2, CH, C, and H is not sufficient to properly predict the catalytic efficiency and carbon deposition, and further investigation of the CO gas-evolving reaction is required to completely understand methane dissociation in steam. The location of alloying element in Ni alloy needed be addressed from the results of ab-inito molecular dynamics (MD). The reaction pathway of methane dissociation associated with CO gas evolution is traced by performing first-principles calculations of the adsorption and activation energies of each dissociation step. During the dissociation process, two alternative reaction steps producing adsorbed C and H or adsorbed CO are critically important in determining coking inhibition as well as H2 gas evolution (i.e., the catalytic efficiency). The theoretical calculations presented here suggest that alloying Ni with Ru is an effective way to reduce carbon deposition and enhance the catalytic efficiency of H2 fueling in solid oxide fuel cells (SOFCs).

  15. Hydrogen production from the steam reforming of bio-butanol over novel supported Co-based bimetallic catalysts.

    Science.gov (United States)

    Cai, Weijie; de la Piscina, Pilar Ramirez; Homs, Narcis

    2012-03-01

    This paper reports the hydrogen production through the steam reforming of a bioresource-derived butanol mixture (butanol:acetone:ethanol=6:3:1 mass ratio) over supported cobalt-based catalysts. The support plays an important role for the catalytic behavior and Co/ZnO exhibits the best catalytic performance compared to Co/TiO(2) and Co/CeO(2). Moreover, a higher hydrogen yield is obtained over bimetallic Co-Ir/ZnO, which shows an increase in H(2) selectivity and a decrease in CH(4) selectivity under steam reforming conditions, compared to Co/ZnO. Raman results of the used catalysts indicate that the addition of Ir could prevent the coke formation to prolong the catalyst stability.

  16. Hydrogen production from oxidative steam reforming of bio-butanol over CoIr-based catalysts: effect of the support.

    Science.gov (United States)

    Cai, Weijie; Piscina, Pilar Ramírez de la; Gabrowska, Klaudia; Homs, Narcís

    2013-01-01

    This paper studies the influence of the support on the behavior of bimetallic CoIr-based catalysts (6.5 wt.% Co, 0.4 wt.% Ir) for hydrogen production from the oxidative steam reforming of bio-butanol raw mixture (butanol/acetone/ethanol = 6/3/1 mass ratio). Catalytic tests were carried out at 500 °C for 60 h with raw mixture/water/air/Ar = 1/10/7.5/12 molar ratio and GHSV = 7500 h(-1). Over CoIr/18CeZrO(2) and CoIr/ZnO the main process which took place was the oxidative steam reforming of the raw mixture. CoIr/18CeZrO(2) showed the better catalytic performance. Characterization of the used catalysts indicated that both active metal sintering and coke formation was prevented on the CoIr/18CeZrO(2) catalyst.

  17. A New Reforming Reaction Mechanism of Carbon Dioxide with Methane on Nano Scale Nickel catalyst

    Directory of Open Access Journals (Sweden)

    Long Wei

    2016-01-01

    Full Text Available The reforming mechanism of CO2-CH4 on Nano scale Ni metal catalyst was investigated using the B3LYP density functional method and MP2/Lanl2dz method. It was found that the reaction include thirteen steps and the activation energy of each step was 44.7175, 200.4707, 171.0781, 307.2596, 124.5252, 330.7904, 593.9056, 177.5526, 226.6793, 277.789 2, 394.5525,399.5340 and 105.4115 kJ·mol−1. The rate determining step was the fourth step. The enthalpy value of each step was 31.6136, 106.7138, −104.2589, 79.9641, 93.5573,174.6 121, 259.6409, −141.9192, −439.9338, −265.4756, −208.3245, 131.6561 and −86.1765 kJ·mol−1.

  18. Intermetallic Alloys as CO Electroreduction Catalysts-Role of Isolated Active Sites

    DEFF Research Database (Denmark)

    Karamad, Mohammadreza; Tripkovic, Vladimir; Rossmeisl, Jan

    2014-01-01

    binary bulk alloys forming from these elements have been investigated using density functional theory calculations. The electronic and geometric properties of the catalyst surface can be tuned by varying the size of the active centers and the elements forming them. We have identified six different...... potentially selective intermetallic surfaces on which CO can be reduced to methanol at potentials comparable to or even slightly positive than those for CO/CO2 reduction to methane on Cu. Common features shared by most of the selective alloys are single TM sites. The role of single sites is to block parasitic...

  19. Hydrogen Production by Catalytic Steam Reforming of Bio-oil, Naphtha and CH4 over C12A7-Mg Catalyst

    Science.gov (United States)

    Pan, Yue; Wang, Zhao-xiang; Kan, Tao; Zhu, Xi-feng; Li, Quan-xin

    2006-06-01

    Hydrogen production by catalytic steam reforming of the bio-oil, naphtha, and CH4 was investigated over a novel metal-doped catalyst of (Ca24Al28O64)4+·4O-/Mg (C12A7-Mg). The catalytic steam reforming was investigated from 250 to 850°C in the fixed-bed continuous flow reactor. For the reforming of bio-oil, the yield of hydrogen of 80% was obtained at 750°C, and the maximum carbon conversion is nearly close to 95% under the optimum steam reforming condition. For the reforming of naphtha and CH4, the hydrogen yield and carbon conversion are lower than that of bio-oil at the same temperature. The characteristics of catalyst were also investigated by XPS. The catalyst deactivation was mainly caused by the deposition of carbon in the catalytic steam reforming process.

  20. Self-cleaning perovskite type catalysts for the dry reforming of methane

    Institute of Scientific and Technical Information of China (English)

    Jehad Abu-Dahrieh a; Alexandre Goguet a; Kening Sun b; David Rooney a

    2014-01-01

    Gas-to-liquid processes are generally used to convert natural gas or other gaseous hydrocarbons into liquid fuels via an intermediate syngas stream. This includes the production of liquid fuels from biomass-derived sources such as biogas. For example, the dry reforming of methane is done by reacting CH4 and CO2, the two main components of natural biogas, into more valuable products, i.e., CO and H2. Nickel containing perovskite type catalysts can promote this reaction, yielding good conversions and selectivities; however, they are prone to coke laydown under certain operating conditions. We investigated the addition of high oxygen mobility dopants such as CeO2, ZrO2, or YSZ to reduce carbon laydown, particularly using reaction conditions that normally result in rapid cok-ing. While doping with YSZ, YDC, GDC, and SDC did not result in any improvement, we show that a Ni perovskite catalyst (Na0.5La0.5Ni0.3Al0.7O2.5) doped with 80.9 ZrO2 15.2 CeO2 gave the lowest amount of carbon formation at 800 °C and activity was maintained over the operating time.

  1. Production of hydrogen from methanol over Cu/ZnO and Cu/ZnO/Al2O3 catalysts prepared by homogeneous precipitation : Steam reforming and oxidative steam reforming

    OpenAIRE

    2006-01-01

    Two series of Cu/ZnO and Cu/ZnO/Al2O3 catalysts with varying Cu/Zn ratio have been prepared by the homogeneous precipitation (hp) method using urea hydrolysis. Steam reforming and oxidative steam reforming of methanol were performed using the hp-Cu/Zn-based catalysts for catalytic production of hydrogen. The hp-Cu/ZnO/Al2O3 catalyst showed a higher activity than the hp-Cu/ZnO catalysts. In both cases, the catalytic activity was well correlated with the surface area of Cu metal, and the maximu...

  2. Hydrothermal Synthesis of Co-Ru Alloy Particle Catalysts for Hydrogen Generation from Sodium Borohydride

    Directory of Open Access Journals (Sweden)

    Marija Kurtinaitienė

    2013-01-01

    Full Text Available We report the synthesis of μm and sub-μm-sized Co, Ru, and Co-Ru alloy species by hydrothermal approach in the aqueous alkaline solutions (pH ≥ 13 containing CoCl2 and/or RuCl3, sodium citrate, and hydrazine hydrate and a study of their catalytic properties for hydrogen generation by hydrolysis of sodium borohydride solution. This way provides a simple platform for fabrication of the ball-shaped Co-Ru alloy catalysts containing up to 12 wt% Ru. Note that bimetallic Co-Ru alloy bowls containing even 7 at.% Ru have demonstrated catalytic properties that are comparable with the ones of pure Ru particles fabricated by the same method. This result is of great importance in view of the preparation of cost-efficient catalysts for hydrogen generation from borohydrides. The morphology and composition of fabricated catalyst particles have been characterized using scanning electron microscopy, energy dispersive X-ray diffraction, and inductively coupled plasma optical emission spectrometry.

  3. CO2 Reforming of CH4 over Nickel and Cobalt Catalysts Prepared from La-Based Perovskite Precursors

    Institute of Scientific and Technical Information of China (English)

    Jianjun Guo; Hui Lou; Yinghong Zhu; Xiaoming Zheng

    2003-01-01

    Four perovskite-type complex oxides (LaNiO3, La2NiO4, LaCoO3 and La2CoO4) were suc-cessfully prepared using two sol-gel methods, the Pechini method (PC) and the citric acid complexingmethod (CC). The catalysts were characterized by XRD and TPR. After reduction, the activity of thecatalysts in the CO2 reforming of methane was tested. Ni-based catalysts from La2NiO4 precursors werethe most active and stable catalyst after calcination above 850 ℃, which gave a methane conversion of0.025 mmol/(g@s) for those prepared by the PC method and 0.020 mmol/(g.s) by the CC method. Itwas proposed that the well-defined structure and lower reducibility is responsible for the unusual catalyticbehavior observed over the pre-reduced La2NiO4 catalyst.

  4. Mixtures of Steel-Making Slag and Carbons as Catalyst for Microwave-Assisted Dry Reforming of CH4

    Institute of Scientific and Technical Information of China (English)

    Jose M. BERMUDEZ; Beatriz FIDALGO; Ana ARENILLAS; J. Angel MENENDEZ

    2012-01-01

    The use of steel-making slag as catalysts for microwave-assisted dry reforming of CH4 was studied.Two carbon materials (an activated carbon and a metallurgical coke),mixtures of the carbon materials and Fe-rich slag,and mixtures of the carbon materials and Ni/Al2O3 were tested as catalysts.The mixtures of slag with carbons gave rise to higher and steadier conversions than those achieved over the carbon materials alone.In addition,the use of the metallurgical coke mixed with metal-rich catalysts gave rise to remarkable results.Thus,no CH4 and CO2 conversions were achieved when coke was used alone,whereas high conversions were obtained when it was mixed with the metal-rich catalysts.

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

    Institute of Scientific and Technical Information of China (English)

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

    2014-01-01

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

  6. Steam reforming of ethanol for hydrogen production over Cu/Co-Mg-Al-based catalysts prepared by hydrotalcite route.

    Science.gov (United States)

    Homsi, Doris; Rached, Jihane Abou; Aouad, Samer; Gennequin, Cédric; Dahdah, Eliane; Estephane, Jane; Tidahy, Haingomalala Lucette; Aboukaïs, Antoine; Abi-Aad, Edmond

    2016-08-23

    The performances of different 5Cu/CoxMg6-xAl2 (x = 0; 2; 4; 6) catalysts prepared by the wet impregnation method were investigated in the ethanol steam-reforming reaction (ESR) at 450 °C during 4 h under a steam/ethanol ratio of 3 (S/E = 3). The best catalyst among the prepared solids was 5Cu/Co6Al2 as it showed a complete ethanol conversion and the highest hydrogen and carbon dioxide productivities. However, following 50 h of aging, the catalyst deactivated due to the formation of a high amount of carbonaceous products detected by differential scanning calorimetry/thermogravimetry. On the other hand, the 5Cu/Co2Mg4Al2 catalyst showed a much lower quantity of coke deposition with no deactivation due to the basic character conferred by the magnesium oxide phase.

  7. A Novel Carbon Nanotube-Supported NiP Amorphous Alloy Catalyst and Its Hydrogenation Activity

    Institute of Scientific and Technical Information of China (English)

    Yan Ju; Fengyi Li

    2006-01-01

    A carbon nanotube-supported NiP amorphous catalyst (NiP/CNT) was prepared by induced reduction. Benzene hydrogenation was used as a probe reaction for the study of catalytic activity. The effects of the support on the activity and thermal stability of the supported catalyst were discussed based on various characterizations, including XRD, TEM, ICP, XPS, H2-TPD, and DTA. In comparison with the NiP amorphous alloy, the benzene conversion on NiP/CNT catalyst was lower, but the specific activity of NiP/CNT was higher, which is attributed to the dispersion produced by the support, an electron-donating effect, and the hydrogen-storage ability of CNT. The NiP/CNT thermal stability was improved because of the dispersion and electronic effects and the good heat-conduction ability of the CNT support.

  8. Steam reforming of methanol over oxide decorated nanoporous gold catalysts: a combined in situ FTIR and flow reactor study.

    Science.gov (United States)

    Shi, J; Mahr, C; Murshed, M M; Gesing, T M; Rosenauer, A; Bäumer, M; Wittstock, A

    2017-03-29

    Methanol as a green and renewable resource can be used to generate hydrogen by reforming, i.e., its catalytic oxidation with water. In combination with a fuel cell this hydrogen can be converted into electrical energy, a favorable concept, in particular for mobile applications. Its realization requires the development of novel types of structured catalysts, applicable in small scale reactor designs. Here, three different types of such catalysts were investigated for the steam reforming of methanol (SRM). Oxides such as TiO2 and CeO2 and mixtures thereof (Ce1Ti2Ox) were deposited inside a bulk nanoporous gold (npAu) material using wet chemical impregnation procedures. Transmission electron and scanning electron microscopy reveal oxide nanoparticles (1-2 nm in size) abundantly covering the strongly curved surface of the nanoporous gold host (ligaments and pores on the order of 40 nm in size). These catalysts were investigated in a laboratory scaled flow reactor. First conversion of methanol was detected at 200 °C. The measured turn over frequency at 300 °C of the CeOx/npAu catalyst was 0.06 s(-1). Parallel investigation by in situ infrared spectroscopy (DRIFTS) reveals that the activation of water and the formation of OHads are the key to the activity/selectivity of the catalysts. While all catalysts generate sufficient OHads to prevent complete dehydrogenation of methanol to CO, only the most active catalysts (e.g., CeOx/npAu) show direct reaction with formic acid and its decomposition to CO2 and H2. The combination of flow reactor studies and in operando DRIFTS, thus, opens the door to further development of this type of catalyst.

  9. Characterization and reactivity of Pd Pt bimetallic supported catalysts obtained by laser vaporization of bulk alloy

    Science.gov (United States)

    Rousset, J. L.; Cadete Santos Aires, F. J.; Bornette, F.; Cattenot, M.; Pellarin, M.; Stievano, L.; Renouprez, A. J.

    2000-09-01

    Bimetallic Pd-Pt clusters produced by laser vaporization of bulk alloy have been deposited on high surface alumina. Energy dispersive X-ray (EDX) analysis and transmission electron microscopy (TEM) show that they have a perfectly well-defined stoichiometry and a narrow range of size. Therefore, they constitute ideal systems to investigate alloying effects towards reactivity. Pd-Pt alloys are already known for their applications in the hydrogenation of unsaturated hydrocarbons, especially aromatics, because this system is highly resistant to sulfur and nitrogen poisoning. In this context, the catalytic properties of this system have been investigated in the hydrogenation of tetralin in the presence of hydrogen sulfide. Preliminary results show that this model catalyst is more sulfur-resistant than each of the pure supported metals prepared by chemical methods.

  10. Dry (CO2) reforming of methane over Pt catalysts studied by DFT and kinetic modeling

    Science.gov (United States)

    Niu, Juntian; Du, Xuesen; Ran, Jingyu; Wang, Ruirui

    2016-07-01

    Dry reforming of methane (DRM) is a well-studied reaction that is of both scientific and industrial importance. In order to design catalysts that minimize the deactivation and improve the selectivity and activity for a high H2/CO yield, it is necessary to understand the elementary reaction steps involved in activation and conversion of CO2 and CH4. In our present work, a microkinetic model based on density functional theory (DFT) calculations is applied to explore the reaction mechanism for methane dry reforming on Pt catalysts. The adsorption energies of the reactants, intermediates and products, and the activation barriers for the elementary reactions involved in the DRM process are calculated over the Pt(1 1 1) surface. In the process of CH4 direct dissociation, the kinetic results show that CH dissociative adsorption on Pt(1 1 1) surface is the rate-determining step. CH appears to be the most abundant species on the Pt(1 1 1) surface, suggesting that carbon deposition is not easy to form in CH4 dehydrogenation on Pt(1 1 1) surface. In the process of CO2 activation, three possible reaction pathways are considered to contribute to the CO2 decomposition: (I) CO2* + * → CO* + O*; (II) CO2* + H* → COOH* + * → CO* + OH*; (III) CO2* + H* → mono-HCOO* + * → bi-HCOO* + * [CO2* + H* → bi-HCOO* + *] → CHO* + O*. Path I requires process to overcome the activation barrier of 1.809 eV and the forward reaction is calculated to be strongly endothermic by 1.430 eV. In addition, the kinetic results also indicate this process is not easy to proceed on Pt(1 1 1) surface. While the CO2 activation by H adsorbed over the catalyst surface to form COOH intermediate (Path II) is much easier to be carried out with the lower activation barrier of 0.746 eV. The Csbnd O bond scission is the rate-determining step along this pathway and the process needs to overcome the activation barrier of 1.522 eV. Path III reveals the CO2 activation through H adsorbed over the catalyst

  11. MECHANISTIC KINETIC MODELS FOR STEAM REFORMING OF CONCENTRATED CRUDE ETHANOL ON NI/AL2O3 CATALYST

    Directory of Open Access Journals (Sweden)

    O. A. OLAFADEHAN

    2015-05-01

    Full Text Available Mechanistic kinetic models were postulated for the catalytic steam reforming of concentrated crude ethanol on a Ni-based commercial catalyst at atmosphere pressure in the temperature range of 673-863 K, and at different catalyst weight to the crude ethanol molar flow rate ratio (in the range 0.9645-9.6451 kg catalyst h/kg mole crude ethanol in a stainless steel packed bed tubular microreactor. The models were based on Langmuir-Hinshelwood-Hougen-Watson (LHHW and Eley-Rideal (ER mechanisms. The optimization routine of Nelder-Mead simplex algorithm was used to estimate the inherent kinetic parameters in the proposed models. The selection of the best kinetic model amongst the rival kinetic models was based on physicochemical, statistical and thermodynamic scrutinies. The rate determining step for the steam reforming of concentrated crude ethanol on Ni/Al2O3 catalyst was found to be surface reaction between chemisorbed CH3O and O when hydrogen and oxygen were adsorbed as monomolecular species on the catalyst surface. Excellent agreement was obtained between the experimental rate of reaction and conversion of crude ethanol, and the simulated results, with ADD% being ±0.46.

  12. Hydrogen production from raw bioethanol steam reforming : optimization of catalyst composition with improved stability against various impurities

    Energy Technology Data Exchange (ETDEWEB)

    Le Valant, A.; Can, F.; Bion, N.; Epron, F.; Duprez, D. [Poitiers Univ., Poitiers (France). Laboratoire de Catalyse en Chimie organique

    2009-07-01

    This study investigated the effects of raw ethanol impurities on catalytic performance during ethanol steam reforming processes. An Rh/MgAI{sub 2}O{sub 4} reference catalyst was used. Steam reforming was conducted in a fixed bed reactor. The study showed that aldehyde, amine, and methanol have no negative impacts on catalytic performance. Deactivation is caused by coke formation as a result of the presence of the impurities in the feed. The composition of the support and metallic phases of the catalyst formulation were then modified in order to improve the stability of the catalyst in the presence of deactivating impurities. Rare earth elements were used to replace magnesium and decrease strong and medium acid sites. Ethanol conversion and hydrogen yield were both increased when the dehydration reaction was disfavoured. The metallic phase was modified by the addition of a second metal. It was concluded that the Rh-NiY-Al{sub 2}O{sub 3} catalyst has the highest hydrogen yield, and is more stable than the reference catalyst. 16 refs., 7 figs.

  13. Biogas reforming on La-promoted NiMgAl catalysts derived from hydrotalcite-like precursors

    Science.gov (United States)

    Serrano-Lotina, A.; Rodríguez, L.; Muñoz, G.; Daza, L.

    Hydrotalcite-like precursors have been synthesized in order to study the influence of lanthanum on the structure and the properties of the precursors, as well as on the catalytic activity and stability of their derived catalyst on biogas reforming. From XRD, and TPO characterization, we confirmed that hydrotalcite-like precursors where obtained. After calcination at 750 °C, Mg(Ni,Al)O solid solution was detected. High surface areas have been obtained finding the highest surface area on the catalyst without lanthanum. TPR experiments were performed in order to study the reducibility of the catalysts. One reduction peak was found in the catalyst without lanthanum while two peaks were observed in the catalysts with lanthanum. A reduction peak at 900 °C was observed over the sample without Ni and La. Catalytic tests, at 700 °C with a feed of CH 4:CO 2 1:1, were performed after appropriate reduction during 50 h. While a decrease on catalytic activity was observed with the addition and the increase of La content, an enhancement in the stability was observed. No sign of deactivation of the catalyst and no carbon deposition were found on the catalysts doped with lanthanum.

  14. Ni-Co/Mg-Al catalyst derived from hydrotalcite-like compound prepared by plasma for dry reforming of methane

    Institute of Scientific and Technical Information of China (English)

    Huali; Long; Yan; Xu; Xiaoqing; Zhang; Shijing; Hu; Shuyong; Shang; Yongxiang; Yin; Xiaoyan; Dai

    2013-01-01

    Ni-Co bimetallic catalysts with different Ni/Co content were derived from cold plasma jet decomposition and reduction of hydrotalcite-like compounds containing Ni,Co,Mg and Al,and their catalytic performance was investigated with dry reforming of methane.Experimental results showed that the hydrotalcite-like precursors could be completely decomposed and partly reduced by cold plasma jet,and the Nicontained catalysts exhibited much higher activity than the catalyst without Ni.Especially,the catalyst with Ni/Co ratio of 8/2 achieved not only the highest conversions of 80.3%and 69.3%for CH4 and CO2,respectively,but also the best stability in 100 h testing.The catalysts were characterized by XRD,XPS,TEM and N2 adsorption techniques,and the results showed that the better performance of the 8Ni2Co bimetallic catalyst was attributed to its higher metal dispersion,smaller metal particle size,as well as the interaction effect between Ni and Co,which were brought by the special catalyst preparation method.

  15. Hydrogen production from steam reforming of ethanol over Ni/MgO-CeO_2 catalyst at low temperature

    Institute of Scientific and Technical Information of China (English)

    石秋杰; 刘承伟; 谌伟庆

    2009-01-01

    MgO,CeO2 and MgO-CeO2 with different mole ratio of Mg:Ce were prepared by solid-phase burning method.Catalysts Ni/MgO,Ni/CeO2 and Ni/MgO-CeO2 were prepared by impregnation method.The catalytic properties were evaluated in ethanol steam reforming(ESR) reaction.Specific surface areas of the supports were measured by nitrogen adsorption-desorption at 77 K,and the catalysts were characterized with X-ray diffraction(XRD),temperature programmed reduction(TPR) and thermogravimetric(TG).The results showed that well...

  16. Tuning the composition of metastable CoxNiyMg100−xy(OH)(OCH3) nanoplates for optimizing robust methane dry reforming catalyst

    DEFF Research Database (Denmark)

    Fan, Xiaoli; Liu, Zhiting; Zhu, Yi-An

    2015-01-01

    of the metastable precursor CoxNiyMg100−x−y(OH)(OCH3) derived from solvothermal synthesis. The catalyst composition and reaction conditions have been modulated to achieve maximum coke resistance and catalyst stability. Long-term stability for 1000 h time on stream at 800°C has been achieved for the optimized Co0.......075Ni7.425Mg92.5O catalyst. The role of Co in the catalyst has been disclosed through kinetic measurements and detailed characterization of the spent catalysts. Co is enriched on the Co–Ni alloy surface under reforming conditions and accelerates the gasification of coke intermediates. Co also enhances...

  17. Washcoating copper catalyst on ZrO2 coated stainless steel plate with yttria sol for steam reforming of methanol in a microreactor

    Energy Technology Data Exchange (ETDEWEB)

    Wang, J.H.; Chen, K.Y. [Yuan Ze Univ., Taiwan (China). Fuel Cell Center; Shen, C.C. [Yuan Ze Univ., Taiwan (China). Dept. of Mechanical Engineering; Yeh, C.T. [Yuan Ze Univ., Taiwan (China). Fuel Cell Center, Dept. of Chemical Engineering and Materials Science

    2009-07-01

    A copper-aluminium (CuO/ZnO-Al2O3) catalyst was washcoated on a microchannel. A brushing method was used to make a slurry with commercial yttria sol for the steam reforming of methanol (SRM). Increases in adhesion were investigated by tuning the solid content (SC) and ratio of the catalyst to the binder in the slurry as well as the pH values and stirring times. Catalyst adhesion was quantified by estimating the weight losses of the catalyst layer. The catalysts were then characterized using X-ray diffraction (XRD); scanning electron microscopy (SEM); X-ray photoelectron spectroscopy (XPS); and temperature programmed reduction (TPR). The micro-reformer was then tested in a steam reforming methanol reaction at temperatures ranging between 210 and 300 degrees C. It was concluded that methanol conversion was lower at 210 degrees C, and increased with increases in temperature.

  18. Effect of Ce and Zr Addition to Ni/SiO2 Catalysts for Hydrogen Production through Ethanol Steam Reforming

    Directory of Open Access Journals (Sweden)

    Jose Antonio Calles

    2015-01-01

    Full Text Available A series of Ni/Ce\\(_{x}\\Zr\\(_{1-x}\\O\\(_{2}\\/SiO\\(_{2}\\ catalysts with different Zr/Ce mass ratios were prepared by incipient wetness impregnation. Ni/SiO\\(_{2}\\, Ni/CeO\\(_{2}\\ and Ni/ZrO\\(_{2}\\ were also prepared as reference materials to compare. Catalysts' performances were tested in ethanol steam reforming for hydrogen production and characterized by XRD, H\\(_{2}\\-temperature programmed reduction (TPR, NH\\(_{3}\\-temperature programmed desorption (TPD, TEM, ICP-AES and N\\(_{2}\\-sorption measurements. The Ni/SiO\\(_{2}\\ catalyst led to a higher hydrogen selectivity than Ni/CeO\\(_{2}\\ and Ni/ZrO\\(_{2}\\, but it could not maintain complete ethanol conversion due to deactivation. The incorporation of Ce or Zr prior to Ni on the silica support resulted in catalysts with better performance for steam reforming, keeping complete ethanol conversion over time. When both Zr and Ce were incorporated into the catalyst, Ce\\(_{x}\\Zr\\(_{1-x}\\O\\(_{2}\\ solid solution was formed, as confirmed by XRD analyses. TPR results revealed stronger Ni-support interaction in the Ce\\(_{x}\\Zr\\(_{1-x}\\O\\(_{2}\\-modified catalysts than in Ni/SiO\\(_{2}\\ one, which can be attributed to an increase of the dispersion of Ni species. All of the Ni/Ce\\(_{x}\\Zr\\(_{1-x}\\O\\(_{2}\\/SiO\\(_{2}\\ catalysts exhibited good catalytic activity and stability after 8 h of time on stream at 600°. The best catalytic performance in terms of hydrogen selectivity was achieved when the Zr/Ce mass ratio was three.

  19. Ni-Pd-Al2O3 catalyst supported on reticulated ceramic foam for dry methane reforming

    Directory of Open Access Journals (Sweden)

    Vesna Nikolić

    2015-03-01

    Full Text Available In the present study, Ni-Pd/Al2O3 catalyst supported on α-Al2O3 based foam was prepared and evaluated in the dry methane reforming process. Corresponding metal chlorides were deposited to the foam surface by impregnation of the foam with ultrasonically aerosolized salt solutions at 473 K and drying at that temperature. Calcination step was excluded and the catalyst was reduced at very low temperature – 533 K. The reforming experiment lasted for 3 h, with standing time of 1 h at the following temperatures: 873, 973 and 1023 K. Conclusions on selectivity, catalytic activity and stability were reached on the basis of CO and H2 yields.

  20. Nickel-carbon nanocomposites prepared using castor oil as precursor: A novel catalyst for ethanol steam reforming

    Science.gov (United States)

    Carreño, Neftalí L. V.; Garcia, Irene T. S.; Raubach, Cristiane W.; Krolow, Mateus; Santos, Cláudia C. G.; Probst, Luiz F. D.; Fajardo, Humberto V.

    A novel and simple method to prepare nickel-based catalysts for ethanol steam reforming is proposed. The present method was developed using castor oil as a precursor. The results clarify that the nickel-carbon (Ni/C) catalyst has a high activity for ethanol steam reforming. It was observed that the catalytic behavior could be modified according to the experimental conditions employed. Moreover, it is interesting to note that the increase in the catalytic activity of the Ni/C nanocomposite over time, at 500 and 600 °C of reaction temperature, may be associated with the formation of filamentous carbon. The preliminary results indicate that the novel methodology used, led to the obtainment of materials with important properties that can be extended to applications in different catalytic process.

  1. In situ X-ray photoelectron spectroscopy of methanol steam reforming on Cu/ZnO catalysts

    OpenAIRE

    2004-01-01

    Cu/ZnO (alumina) catalysts have found industrial use for the low-temperature methanol synthesis, for the low-temperature water-gas shift reaction, and for the steam reforming of methanol. An important application could be the onboard production of hydrogen for fuel cell application. It is the proposed synergistic effect in the binary copper/zinc oxide that makes this system interesting for investigation. The knowledge of the relationship between the catalytic activity, surface structure, a...

  2. Production of renewable hydrogen from aqueous-phase reforming of glycerol over Pt catalysts supported on different oxides

    Energy Technology Data Exchange (ETDEWEB)

    Menezes, Andre O. [Instituto Nacional de Tecnologia/MCT, Laboratorio de Catalise, Av. Venezuela 82/507, Rio de Janeiro/RJ 22081-312 (Brazil); Instituto Militar de Engenharia, Praca General Tiburcio, 80 Praia Vermelha, Rio de Janeiro/RJ 22290-270 (Brazil); Rodrigues, Michelly T.; Zimmaro, Adriana; Fraga, Marco A. [Instituto Nacional de Tecnologia/MCT, Laboratorio de Catalise, Av. Venezuela 82/507, Rio de Janeiro/RJ 22081-312 (Brazil); Borges, Luiz E.P. [Instituto Militar de Engenharia, Praca General Tiburcio, 80 Praia Vermelha, Rio de Janeiro/RJ 22290-270 (Brazil)

    2011-02-15

    Aqueous-phase reforming of oxygenated hydrocarbons for hydrogen production presents several advantages as feed molecules can be easily found in a wide range of biomass, there is no need for its vaporization and the process allows thorough exploitation of the environmental benefits of using hydrogen as an energy carrier. The use of glycerol in particular is motivated due to its availability as a consequence of increasing biodiesel production worldwide. In this contribution, the performance of Pt-based catalysts supported on different oxides (Al{sub 2}O{sub 3}, ZrO{sub 2}, MgO and CeO{sub 2}) is studied on glycerol reforming. All catalysts led to a hydrogen-rich gas phase. However, a good potential activity with high production of hydrogen and low concentration of undesired hydrocarbons was accomplished over the catalysts supported on MgO and ZrO{sub 2}. The high electron donating character of such oxides indicates the influence of the nature of the support in catalytic performance for glycerol reforming. (author)

  3. Dynamical Properties of a Ru/MgAl2O4 Catalyst during Reduction and Dry Methane Reforming

    DEFF Research Database (Denmark)

    Kehres, Jan; Jakobsen, Jon Geest; Andreasen, Jens Wenzel;

    2012-01-01

    of the size regime attributed to scattering from Ru/RuO2-particles decreases slightly by about 0.2 nm during the reduction. Dry methane reforming experiments were performed in a temperature interval from 723 to 1023 K by applying a gas mixture of carbon dioxide and methane in molar ratio of 3:1. The catalyst......Combined in situ small- and wide-angle X-ray scattering (SAXS/WAXS) studies were performed in a new laboratory setup to investigate the dynamical properties of a ruthenium/spinel (Ru/MgAl2O4) catalyst, w(Ru) = 4 wt %, during the reduction and subsequent dry methane reforming. The Ru particles...... did not show any deactivation during the experiment of overall 32 h, indicated by stable turnover frequencies for methane. The mean Ru-particle diameter remained constant during the dry methane reforming experiments, revealing a high sintering stability of the Ru/MgAl2O4 catalyst....

  4. Stability improvements of Ni/{alpha}-Al{sub 2}O{sub 3} catalysts to obtain hydrogen from methane reforming

    Energy Technology Data Exchange (ETDEWEB)

    Pompeo, Francisco; Nichio, Nora N. [CINDECA, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, CONICET, 47 N 257, 1900 La Plata (Argentina); Facultad de Ingenieria, Universidad Nacional de La Plata, 1 esq. 47, 1900 La Plata (Argentina); Gazzoli, Delia [Dipartimento di Chimica, Universita di Roma ' ' La Sapienza' ' , P.le A. Moro 5, 00185 Rome (Italy)

    2009-03-15

    Ni catalysts supported on commercial {alpha}-Al{sub 2}O{sub 3} modified by addition of CeO{sub 2} and/or ZrO{sub 2} were prepared in the present work. Since the principal objective was to evaluate the behavior of these systems and the support effect on the stability, methane reforming reactions were studied with steam, carbon dioxide, partial oxidation and mixed reforming. Results show that catalysts supported on Ce-Zr-{alpha}-Al{sub 2}O{sub 3} composites present better reforming activity and stability noticeably higher than in the case of the reference support. With respect to composites, the presence of mixed oxides of Ce{sub x}Zr{sub 1-x}O{sub 2} type facilitates the formation of active phases with higher interaction. This fact reduces the deactivation by sintering conferring to the system a higher contribution of adsorbed oxygen species, favoring the deposited carbon elimination. These improvements resulted in being dependent on the Ce:Zr ratio of the composite, thus obtaining more stable catalysts for Ce:Zr = 4:1 ratios. (author)

  5. Steam reforming of acetic acid as a biomass derived oxygenate: Bifunctional pathway for hydrogen formation over Pt/ZrO2 catalysts.

    NARCIS (Netherlands)

    Takanabe, K.; Takanabe, Kazuhiro; Aika, Ken-ichi; Inazu, Koji; Baba, Toshihide; Seshan, Kulathuiyer; Lefferts, Leonardus

    2006-01-01

    Mechanistic studies on steam reforming of acetic acid over Pt/ZrO2 catalysts were performed as extension of our previous work [K. Takanabe, K. Aika, K. Seshan, L. Lefferts, J. Catal. 227 (2004) 101]. An overall picture of the bifunctional mechanism is established for steam reforming of acetic acid,

  6. Steam reforming of biomass gasification tar using benzene as a model compound over various Ni supported metal oxide catalysts.

    Science.gov (United States)

    Park, Hyun Ju; Park, Sung Hoon; Sohn, Jung Min; Park, Junhong; Jeon, Jong-Ki; Kim, Seung-Soo; Park, Young-Kwon

    2010-01-01

    The steam reforming of benzene as a model compound of biomass gasification tar was carried out over various Ni/metal oxide catalysts. The effects of the support, temperature, Ni-precursor, Ni loading and reaction time were examined, and their catalytic performance was compared with that of a commercial Ni catalyst. Among the Ni/metal oxide catalysts used, 15 wt% Ni/CeO(2)(75%)-ZrO(2)(25%) showed the highest catalytic performance owing to its greater redox characteristics and increased surface area, irrespective of the reaction temperature. The catalytic activity of 15 wt% Ni/CeO(2)(75%)-ZrO(2)(25%) was higher than that of the commercial Ni catalyst. Moreover, the catalyst activity was retained due to its excellent resistance to coke deposition even after 5h. The Ni-precursor played a critical role in the catalytic activity. With the exception of nickel nitrate, all the Ni-precursors (chloride and sulfate) caused deactivation of the catalyst.

  7. Combination of Partial Oxidation and CO2 Reforming of Methane over Monolithic Ni/CeO2-ZrO2/γ-Al2O3 Catalyst

    Institute of Scientific and Technical Information of China (English)

    Xuan LI; Yun TENG; Mao Chu GONG; Yao Qiang CHEN

    2005-01-01

    A new monolithic Ni/CeO2-ZrO2/γ-Al2O3 catalyst for combined partial oxidation and CO2 reforming of methane was prepared. The result shows that the addition of O2 to the feed can improve the activity of the catalyst and adjust the H2/CO ratio of the productive gases.

  8. Structured Ni catalysts on porous anodic alumina membranes for methane dry reforming: NiAl 2 O 4 formation and characterization

    KAUST Repository

    Zhou, Lu

    2015-06-29

    This communication presents the successful design of a structured catalyst based on porous anodic alumina membranes for methane dry reforming. The catalyst with a strong Ni-NiAl2O4 interaction shows both excellent activity and stability. This journal is © The Royal Society of Chemistry.

  9. Steam reforming of methane over Ni catalysts prepared from hydrotalcite-type precursors:Catalytic activity and reaction kinetics

    Institute of Scientific and Technical Information of China (English)

    Yang Qi; Zhenmin Cheng; Zhiming Zhou

    2015-01-01

    Ni/Mg–Al catalysts derived from hydrotalcite-type precursors were prepared by a co-precipitation technique and applied to steam reforming of methane. By comparison with Ni/γ-Al2O3 and Ni/α-Al2O3 catalysts prepared by in-cipient wetness impregnation, the Ni/Mg–Al catalyst presented much higher activity as a result of higher specific surface area and better Ni dispersion. The Ni/Mg–Al catalyst with a Ni/Mg/Al molar ratio of 0.5:2.5:1 exhibited the highest activity for steam methane reforming and was selected for kinetic investigation. With external and inter-nal diffusion limitations eliminated, kinetic experiments were carried out at atmospheric pressure and over a temperature range of 823–973 K. The results demonstrated that the overal conversion of CH4 and the conversion of CH4 to CO2 were strongly influenced by reaction temperature, residence time of reactants as wel as molar ratio of steam to methane. A classical Langmuir–Hinshelwood kinetic model proposed by Xu and Froment (1989) fitted the experimental data with excellent agreement. The estimated adsorption parameters were consistent thermodynamical y.

  10. Study on Coke Formation and Stability of Nickel-Based Catalysts in CO2 Reforming of CH4

    Institute of Scientific and Technical Information of China (English)

    黎先财; 吴敏; 杨沂凤; 何琲

    2004-01-01

    CO2 reforming of CH4 over nickel-based catalysts was investigated by using a fixed-bed reactor. Catalytic activity and amount of carbon deposition effects by nickel loading content, rare earth promoter and promoter contents were evaluated. It is found that nickel loading as well as reaction temperature can influence the activity and carbon deposition amounts,and with the addition of rare earth promoter, it can greatly improve the catalytic activity and exert a strong effect on the anticoking performance of the catalysts. The 5.0%(mass fraction)Ni-0.75%La-BaTiO3 catalyst shows great resistance to coke formation and higher thermal stability as well as the catalytic activity.

  11. Bench-Scale Monolith Autothermal Reformer Catalyst Screening Evaluations in a Micro-Reactor With Jet-A Fuel

    Science.gov (United States)

    Tomsik, Thomas M.; Yen, Judy C.H.; Budge, John R.

    2006-01-01

    Solid oxide fuel cell systems used in the aerospace or commercial aviation environment require a compact, light-weight and highly durable catalytic fuel processor. The fuel processing method considered here is an autothermal reforming (ATR) step. The ATR converts Jet-A fuel by a reaction with steam and air forming hydrogen (H2) and carbon monoxide (CO) to be used for production of electrical power in the fuel cell. This paper addresses the first phase of an experimental catalyst screening study, looking at the relative effectiveness of several monolith catalyst types when operating with untreated Jet-A fuel. Six monolith catalyst materials were selected for preliminary evaluation and experimental bench-scale screening in a small 0.05 kWe micro-reactor test apparatus. These tests were conducted to assess relative catalyst performance under atmospheric pressure ATR conditions and processing Jet-A fuel at a steam-to-carbon ratio of 3.5, a value higher than anticipated to be run in an optimized system. The average reformer efficiencies for the six catalysts tested ranged from 75 to 83 percent at a constant gas-hourly space velocity of 12,000 hr 1. The corresponding hydrocarbon conversion efficiency varied from 86 to 95 percent during experiments run at reaction temperatures between 750 to 830 C. Based on the results of the short-duration 100 hr tests reported herein, two of the highest performing catalysts were selected for further evaluation in a follow-on 1000 hr life durability study in Phase II.

  12. Hydrogen production from raw bioethanol steam reforming: optimization of catalyst composition with improved stability against various impurities

    Energy Technology Data Exchange (ETDEWEB)

    Le Valant, A.; Can, F.; Bion, N.; Epron, F.; Duprez, D. [Laboratoire de Catalyse en Chimie organique, Univ. de Poitiers, Poitiers Cedex (France)], E-mail: florence.epron.cognet@univ-poitiers.fr

    2009-07-01

    Usually, ethanol steam reforming is performed using pure ethanol, whereas the use of raw bioethanol is of major importance for a cost effective industrial application. Raw bioethanol contains higher alcohols as the main impurities and also aldehydes, amines, acids and esters. The effect of these impurities on the catalytic performances for ethanol steam reforming (ESR) has been studied, using a reference catalyst, Rh/MgAl{sub 2}O{sub 4}. It was shown that the aldehyde, the amine and methanol has no negative effect on the catalytic performances, contrary to the ester, acid and higher alcohols. The deactivation is mainly explained by coke formation favored by the presence of these impurities in the feed. In order to improve the stability of the catalyst and its performances in the presence of these deactivating impurities, the catalyst formulation, i.e. the composition of the support and of the metallic phase, was modified. The addition of rare earth elements instead of magnesium to the alumina support leads to a decrease of the strong and medium acid sites and to an increase of the basicity. On these modified supports, the dehydration reaction, leading to olefins, which are coke precursors, is disfavored, the ethanol conversion and the hydrogen yield are increased. The best catalytic performances were obtained with Rh/Y-Al{sub 2}O{sub 3}. Then, the metallic phase was also modified by adding a second metal (Ni, Pt or Pd). The Rh-Ni/Y-Al{sub 2}O{sub 3} catalyst leads to the highest hydrogen yield. This catalyst, tested in the presence of raw bioethanol during 24h was very stable compared to the reference catalyst Rh/MgAl{sub 2}O{sub 4}, which was strongly deactivated after 2h of time-on-stream. (author)

  13. Deactivation Studies of Rh/Ce0.8Zr0.2O2 Catalysts in Low Temperature Ethanol Steam Reforming

    Energy Technology Data Exchange (ETDEWEB)

    Platon, Alex; Roh, Hyun-Seog; King, David L.; Wang, Yong

    2007-10-30

    Rapid deactivation of Rh/Ce0.8Zr0.2O2 catalysts in low temperature ethanol steam reforming was studied. A significant build-up of carbonaceous intermediate, instead of carbon deposit, was observed at a lower reaction temperature which was attributed to the rapid catalyst deactivation. Co-feed experiments indicated that acetone and ethylene caused more severe catalyst deactivation than other oxygenates such as acidic acid and acetaldehyde.

  14. Microstructural characterization of Cu/ZnO/Al2O3 catalysts for the synthesis and steam reforming of methanol

    OpenAIRE

    2008-01-01

    Cu/ZnO/Al2O3 catalysts represent a versatile catalyst system for methanol chemistry, including the synthesis and steam reforming of methanol. Formally, the steam reforming of methanol is the reverse of methanol synthesis from CO2 and H2. In the present work a set of differently prepared Cu/ZnO/Al2O3 catalysts with a fixed composition of Cu/Zn/Al = 60:30:10 were investigated by in situ bulk techniques, X-ray diffraction, and X-ray absorption spectroscopy. Additionally, microscopic and morpholo...

  15. The features of CNT growth on catalyst-content amorphous alloy layer by CVD-method

    Science.gov (United States)

    Dubkov, S.; Bulyarskii, S.; Pavlov, A.; Trifonov, A.; Kitsyuk, E.; Mierczynski, P.; Maniecki, T.; Ciesielski, R.; Gavrilov, S.; Gromov, D.

    2016-12-01

    This work is devoted to the CVD-synthesis of arrays of carbon nanotubes (CNTs) on Co-Zr-N-(O), Ni-Nb-N-(O), Co- Ta-N-(O) catalytic alloy films from gas mixture of C2H2+NH3+Ar at a substrate temperature of about 550°C.Heating of the amorphous alloy causes its crystallization and squeezing of the catalytic metal onto the surface. As a result, small catalyst particles are formed on the surface. The CNT growth takes place after wards on these particles. It should be noted that the growth of CNT arrays on these alloys is insensitive to the thickness of alloy film, which makes this approach technically attractive. In particular, the possibility of local CNT growth at the ends of the Co-Ta-N-(O) film and three-level CNT growth at the end of more complex structure SiO2/Ni-Nb-N-O/SiO2/Ni-Nb-N-O/SiO2/Ni-Nb-N-O/SiO2 is demonstrated.

  16. Production of Synthesis Gas via Methane Reforming with CO2 on Ni/SiO2 Catalysts Promoted by Alkali and Alkaline Earth Metals

    Institute of Scientific and Technical Information of China (English)

    陈平; 侯昭胤; 郑小明

    2005-01-01

    Ni/SiO2 catalysts promoted by alkali metals K and Cs or alkaline earth metals Mg, Ca, Sr and Ba were prepared, characterized by H2-TPR and XRD, and used for the production of synthesis gas via methane reforming with CO2. Though K and Cs promoted Ni catalysts could eliminate coke deposition, the reforming activity of these promoted catalysts was decreased heavily. Mg and Ca promoted Ni/SiO2 catalysts exhibited excellent coke resistance ability with minor loss of the reforming activity of Ni/SiO2. Ba showed poor coke resistance ability and small amount of Sr increased the formation of coke. The possible mechanism of these promoters was discussed.

  17. Production of CO-rich Hydrogen Gas from Methane Dry Reforming over Co/CeO2 Catalyst

    Directory of Open Access Journals (Sweden)

    Bamidele V. Ayodele

    2016-08-01

    Full Text Available Production of CO-rich hydrogen gas from methane dry reforming was investigated over CeO2-supported Co catalyst. The catalyst was synthesized by wet impregnation and subsequently characterized by field emission scanning electron microscope (FESEM, energy dispersion X-ray spectroscopy (EDX, liquid N2 adsorption-desorption, X-ray diffraction (XRD, Fourier transform infrared spectroscopy (FTIR and thermogravimetric analysis (TGA for the structure, surface and thermal properties. The catalytic activity test of the Co/CeO2 was investigated between 923-1023 K under reaction conditions in a stainless steel fixed bed reactor. The composition of the products (CO2 and H2 from the methane dry reforming reaction was measured by gas chromatography (GC coupled with thermal conductivity detector (TCD. The effects of feed ratios and reaction temperatures were investigated on the catalytic activity toward product selectivity, yield, and syngas ratio. Significantly, the selectivity and yield of both H2 and CO increases with feed ratio and temperature. However, the catalyst shows higher activity towards CO selectivity. The highest H2 and CO selectivity of 19.56% and 20.95% respectively were obtained at 1023 K while the highest yield of 41.98% and 38.05% were recorded for H2 and CO under the same condition. Copyright © 2016 BCREC GROUP. All rights reserved Received: 21st January 2016; Revised: 23rd February 2016; Accepted: 23rd February 2016 How to Cite: Ayodele, B.V., Khan, M.R., Cheng, C. K. (2016. Production of CO-rich Hydrogen Gas from Methane Dry Reforming over Co/CeO2 Catalyst. Bulletin of Chemical Reaction Engineering & Catalysis, 11 (2: 210-219 (doi:10.9767/bcrec.11.2.552.210-219 Permalink/DOI: http://dx.doi.org/10.9767/bcrec.11.2.552.210-219

  18. Effects of Selected Promoters on Ni/γ-Al2O3 Catalyst Performance in Methane Dry Reforming%Effects of Selected Promoters on Ni/γ-Al2O3Catalyst Performance in Methane Dry Reforming

    Institute of Scientific and Technical Information of China (English)

    Ahmed S. A.AL-FATESH; Anis H. FAKEEHA; Ahmed E. ABASAEED

    2011-01-01

    The Ni catalysts supported on γ-Al2O3 were synthesized by an impregnation method.Their catalytic performance in methane dry reforming was investigated.The reforming reactions were carried out in a mieroreactor using a CO2∶CH4 feed ratio of 1∶1,a F/W =2640ml/(h·g),reaction temperatures between 500-850 ℃,and at atmospheric pressure.The influence of Ca,Ce,and Zr promoters on catalyst stability,coke deposition,and the H2/CO ratio were also studied.Effluents were analyzed using an online gas chromatograph equipped with a thermal conductivity detector.The spent and fresh catalysts were characterized by scanning electron microscopy and thermogravimetric analysis.It was found that 3%Ni/γ-Al2O3 promoted with 0.15% Ce and 0.05% Ca gave the best performance and resulted in less coke formation.The highest CH4 and CO2 conversion activities were found to be 94.1% and 98.3% at 850 ℃,respectively.Stability tests were carried out for 130 h and this provided a H2 yield of 91%.Moreover,the amount of formed carbon was negligible and did not increase to more than 1.5 wt%.

  19. Deactivation mechanisms of Ni-based tar reforming catalysts as monitored by X-ray absorption spectroscopy.

    Science.gov (United States)

    Yung, Matthew M; Kuhn, John N

    2010-11-02

    Deactivation mechanisms of alumina-supported, Ni-based catalysts for tar reforming in biomass-derived syngas were evaluated using extended X-ray absorption fine structure (EXAFS) spectroscopy. Catalysts were characterized before and after catalytic reaction cycles and regeneration procedures, which included oxidation by a mixture of steam and air, and reduction in hydrogen. Qualitative analysis of the EXAFS spectra revealed that oxidation of a portion of the Ni in the catalysts to form an oxide phase and/or a sulfide phase were likely scenarios that led to catalyst deactivation with time-on-stream and with increased reaction cycles. Deactivation through carbon deposition, phosphorus poisoning, or changes in particle size were deemed as unlikely causes. Quantitative analysis of the EXAFS spectra indicated sulfur poisoning occurred with time-on-stream, and the contaminating species could not be completely removed during the regeneration protocols. The results also verified that Ni-containing oxide phases (most likely a spinel also containing Mg and Al) formed and contributed to the deactivation. This study validates the need for developing catalyst systems that will protect Ni from sulfur poisoning and oxide formation at elevated reaction and regeneration temperatures.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2005-09-18

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

  1. The Integration of a Structural Water Gas Shift Catalyst with a Vanadium Alloy Hydrogen Transport Device

    Energy Technology Data Exchange (ETDEWEB)

    Barton, Thomas; Argyle, Morris; Popa, Tiberiu

    2009-06-30

    This project is in response to a requirement for a system that combines water gas shift technology with separation technology for coal derived synthesis gas. The justification of such a system would be improved efficiency for the overall hydrogen production. By removing hydrogen from the synthesis gas stream, the water gas shift equilibrium would force more carbon monoxide to carbon dioxide and maximize the total hydrogen produced. Additional benefit would derive from the reduction in capital cost of plant by the removal of one step in the process by integrating water gas shift with the membrane separation device. The answer turns out to be that the integration of hydrogen separation and water gas shift catalysis is possible and desirable. There are no significant roadblocks to that combination of technologies. The problem becomes one of design and selection of materials to optimize, or at least maximize performance of the two integrated steps. A goal of the project was to investigate the effects of alloying elements on the performance of vanadium membranes with respect to hydrogen flux and fabricability. Vanadium was chosen as a compromise between performance and cost. It is clear that the vanadium alloys for this application can be produced, but the approach is not simple and the results inconsistent. For any future contracts, large single batches of alloy would be obtained and rolled with larger facilities to produce the most consistent thin foils possible. Brazing was identified as a very likely choice for sealing the membranes to structural components. As alloying was beneficial to hydrogen transport, it became important to identify where those alloying elements might be detrimental to brazing. Cataloging positive and negative alloying effects was a significant portion of the initial project work on vanadium alloying. A water gas shift catalyst with ceramic like structural characteristics was the second large goal of the project. Alumina was added as a

  2. The Integration of a Structural Water Gas Shift Catalyst with a Vanadium Alloy Hydrogen Transport Device

    Energy Technology Data Exchange (ETDEWEB)

    Barton, Thomas; Argyle, Morris; Popa, Tiberiu

    2009-06-30

    This project is in response to a requirement for a system that combines water gas shift technology with separation technology for coal derived synthesis gas. The justification of such a system would be improved efficiency for the overall hydrogen production. By removing hydrogen from the synthesis gas stream, the water gas shift equilibrium would force more carbon monoxide to carbon dioxide and maximize the total hydrogen produced. Additional benefit would derive from the reduction in capital cost of plant by the removal of one step in the process by integrating water gas shift with the membrane separation device. The answer turns out to be that the integration of hydrogen separation and water gas shift catalysis is possible and desirable. There are no significant roadblocks to that combination of technologies. The problem becomes one of design and selection of materials to optimize, or at least maximize performance of the two integrated steps. A goal of the project was to investigate the effects of alloying elements on the performance of vanadium membranes with respect to hydrogen flux and fabricability. Vanadium was chosen as a compromise between performance and cost. It is clear that the vanadium alloys for this application can be produced, but the approach is not simple and the results inconsistent. For any future contracts, large single batches of alloy would be obtained and rolled with larger facilities to produce the most consistent thin foils possible. Brazing was identified as a very likely choice for sealing the membranes to structural components. As alloying was beneficial to hydrogen transport, it became important to identify where those alloying elements might be detrimental to brazing. Cataloging positive and negative alloying effects was a significant portion of the initial project work on vanadium alloying. A water gas shift catalyst with ceramic like structural characteristics was the second large goal of the project. Alumina was added as a

  3. Ultrasmall PdmMn1-mOx binary alloyed nanoparticles on graphene catalysts for ethanol oxidation in alkaline media

    Science.gov (United States)

    Ahmed, Mohammad Shamsuddin; Park, Dongchul; Jeon, Seungwon

    2016-03-01

    A rare combination of graphene (G)-supported palladium and manganese in mixed-oxides binary alloyed catalysts (BACs) have been synthesized with the addition of Pd and Mn metals in various ratios (G/PdmMn1-mOx) through a facile wet-chemical method and employed as an efficient anode catalyst for ethanol oxidation reaction (EOR) in alkaline fuel cells. The as prepared G/PdmMn1-mOx BACs have been characterized by several instrumental techniques; the transmission electron microscopy images show that the ultrafine alloyed nanoparticles (NPs) are excellently monodispersed onto the G. The Pd and Mn in G/PdmMn1-mOx BACs have been alloyed homogeneously, and Mn presents in mixed-oxidized form that resulted by X-ray diffraction. The electrochemical performances, kinetics and stability of these catalysts toward EOR have been evaluated using cyclic voltammetry in 1 M KOH electrolyte. Among all G/PdmMn1-mOx BACs, the G/Pd0.5Mn0.5Ox catalyst has shown much superior mass activity and incredible stability than that of pure Pd catalysts (G/Pd1Mn0Ox, Pd/C and Pt/C). The well dispersion, ultrafine size of NPs and higher degree of alloying are the key factor for enhanced and stable EOR electrocatalysis on G/Pd0.5Mn0.5Ox.

  4. Bi-Sn alloy catalyst for simultaneous morphology and doping control of silicon nanowires in radial junction solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Zhongwei [National Laboratory of Solid State Microstructures and School of Electronics Science and Engineering/Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093 (China); School of Science, Nantong University, Nantong 226000 (China); Lu, Jiawen; Qian, Shengyi; Xu, Jun; Xu, Ling; Wang, Junzhuan; Shi, Yi; Chen, Kunji [National Laboratory of Solid State Microstructures and School of Electronics Science and Engineering/Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093 (China); Misra, Soumyadeep; Roca i Cabarrocas, Pere [LPICM, CNRS, Ecole Polytechnique, Université Paris-Saclay, 91128 Palaiseau (France); Yu, Linwei, E-mail: yulinwei@nju.edu.cn, E-mail: linwei.yu@polytechnique.edu [National Laboratory of Solid State Microstructures and School of Electronics Science and Engineering/Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093 (China); LPICM, CNRS, Ecole Polytechnique, Université Paris-Saclay, 91128 Palaiseau (France)

    2015-10-19

    Low-melting point metals such as bismuth (Bi) and tin (Sn) are ideal choices for mediating a low temperature growth of silicon nanowires (SiNWs) for radial junction thin film solar cells. The incorporation of Bi catalyst atoms leads to sufficient n-type doping in the SiNWs core that exempts the use of hazardous dopant gases, while an easy morphology control with pure Bi catalyst has never been demonstrated so far. We here propose a Bi-Sn alloy catalyst strategy to achieve both a beneficial catalyst-doping and an ideal SiNW morphology control. In addition to a potential of further growth temperature reduction, we show that the alloy catalyst can remain quite stable during a vapor-liquid-solid growth, while providing still sufficient n-type catalyst-doping to the SiNWs. Radial junction solar cells constructed over the alloy-catalyzed SiNWs have demonstrated a strongly enhanced photocurrent generation, thanks to optimized nanowire morphology, and largely improved performance compared to the reference samples based on the pure Bi or Sn-catalyzed SiNWs.

  5. 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.

  6. A comparative parametric study of a catalytic plate methane reformer coated with segmented and continuous layers of combustion catalyst for hydrogen production

    Science.gov (United States)

    Mundhwa, Mayur; Parmar, Rajesh D.; Thurgood, Christopher P.

    2017-03-01

    A parametric comparison study is carried out between segmented and conventional continuous layer configurations of the coated combustion-catalyst to investigate their influence on the performance of methane steam reforming (MSR) for hydrogen production in a catalytic plate reactor (CPR). MSR is simulated on one side of a thin plate over a continuous layer of nickel-alumina catalyst by implementing an experimentally validated surface microkinetic model. Required thermal energy for the MSR reaction is supplied by simulating catalytic methane combustion (CMC) on the opposite side of the plate over segmented and continuous layer of a platinum-alumina catalyst by implementing power law rate model. The simulation results of both coating configurations of the combustion-catalyst are compared using the following parameters: (1) co-flow and counter-flow modes between CMC and MSR, (2) gas hourly space velocity and (3) reforming-catalyst thickness. The study explains why CPR designed with the segmented combustion-catalyst and co-flow mode shows superior performance not only in terms of high hydrogen production but also in terms of minimizing the maximum reactor plate temperature and thermal hot-spots. The study shows that the segmented coating requires 7% to 8% less combustion-side feed flow and 70% less combustion-catalyst to produce the required flow of hydrogen (29.80 mol/h) on the reforming-side to feed a 1 kW fuel-cell compared to the conventional continuous coating of the combustion-catalyst.

  7. Preparation, structural characterization and catalytic properties of Co/CeO2 catalysts for the steam reforming of ethanol and hydrogen production

    Science.gov (United States)

    Lovón, Adriana S. P.; Lovón-Quintana, Juan J.; Almerindo, Gizelle I.; Valença, Gustavo P.; Bernardi, Maria I. B.; Araújo, Vinícius D.; Rodrigues, Thenner S.; Robles-Dutenhefner, Patrícia A.; Fajardo, Humberto V.

    2012-10-01

    In this paper, Co/CeO2 catalysts, with different cobalt contents were prepared by the polymeric precursor method and were evaluated for the steam reforming of ethanol. The catalysts were characterized by N2 physisorption (BET method), X-ray diffraction (XRD), UV-visible diffuse reflectance, temperature programmed reduction analysis (TPR) and field emission scanning electron microscopy (FEG-SEM). It was observed that the catalytic behavior could be influenced by the experimental conditions and the nature of the catalyst employed. Physical-chemical characterizations revealed that the cobalt content of the catalyst influences the metal-support interaction which results in distinct catalyst performances. The catalyst with the highest cobalt content showed the best performance among the catalysts tested, exhibiting complete ethanol conversion, hydrogen selectivity close to 66% and good stability at a reaction temperature of 600 °C.

  8. Aqueous-phase reforming of biomass using various types of supported precious metal and raney-nickel catalysts for hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Meryemoglu, Bahar; Hesenov, Arif; Irmak, Sibel [Department of Chemistry, Cukurova University, Arts and Sciences Faculty, Balcali, Adana 01330 (Turkey); Atanur, Osman Malik [International Centre for Hydrogen Energy Technologies (UNIDO-ICHET), Cevizlibag, 34015 Zeytinburnu, Istanbul (Turkey); Erbatur, Oktay [Department of Chemistry, Cukurova University, Arts and Sciences Faculty, Balcali, Adana 01330 (Turkey); International Centre for Hydrogen Energy Technologies (UNIDO-ICHET), Cevizlibag, 34015 Zeytinburnu, Istanbul (Turkey)

    2010-11-15

    Aqueous-phase reforming (APR) of real biomass was studied for production of hydrogen gas. Wheat straw, an abundant by-product from wheat production was used as representative lignocellulosic biomass. Wheat straw was hydrolyzed in an environmentally benign-sub critical water condition. APR experiments of wheat straw hydrolysates were performed using commercial catalysts which were made of Pt, Pd and Ru doped on carbon, activated carbon and alumina supports for production of hydrogen rich gas mixture. The activity and selectivity of two commercial raney-nickel catalysts were also monitored in terms of hydrogen production. Among the precious metal catalysts tested, activity of the metals for hydrogen production was in the following descending order: Pt > Ru > Pd. Results indicated that alumina support significantly lowered the catalytic performance of the catalysts. Based on whole catalyst material, raney-nickel catalysts were more active than supported precious metal catalysts tested. (author)

  9. Activity and Stability of Rare Earth-Based Hydride Alloys as Catalysts of Hydrogen Absorption-Oxidation Reactions

    Institute of Scientific and Technical Information of China (English)

    Ying Taokai(应桃开); Gao Xueping(高学平); Hu Weikang(胡伟康); Noréus Dag

    2004-01-01

    Rare earth-based AB5-type hydrogen storage alloys as catalysts of hydrogen-diffusion electrodes for hydrogen absorption and oxidation reactions in alkaline fuel cells were investigated. It is demonstrated that the meta-hydride hydrogen-diffusion electrodes could be charged by hydrogen gas and electrochemically discharged at the same time to retain a stable oxidation potential for a long period. The catalytic activities and stability are almost comparable with a Pt catalyst on the active carbon. Further improvement of performances is expected via reduction of catalyst size into nanometers.

  10. Producer gas cleaning in a dual fluidized bed reformer - a comparative study of performance with ilmenite and a manganese oxide as catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Berguerand, Nicolas; Lind, Fredrik; Seemann, Martin; Thunman, Henrik [Chalmers University of Technology, Department of Energy and Environment, Goeteborg (Sweden)

    2012-09-15

    Secondary catalytic gas conditioning is one strategy to eliminate tars formed in a producer gas during biomass gasification. However, most catalysts tend to lose their tar reforming activity after a short period of operation due to carbon formation. A novel technique for catalytic gas cleaning based on two interconnected fluidized beds has been investigated; this technique can be applied to all types of gasifiers. The idea is to reform the tar components into useful molecules - even at high tar contents - by means of a circulating catalyst. More precisely, the producer gas is cleaned with catalyst in one of the reactors, referred to as the fuel reactor, while the catalyst is continuously regenerated in another reactor, the air reactor (AR). The system described here is coupled with the Chalmers 2-4 MW{sub th} biomass gasifier while the AR is fed with nitrogen-diluted air. The effect of different catalysts on both the tar content and the gas composition was investigated. Some of the tested materials do not only reform tars, they also influence the H{sub 2}/CO ratio in a beneficial manner; in particular, ratios closer to 3 in the reformed gas are favorable if subsequent methanation is implemented. In this paper, comparative results based on testing with manganese- and iron-based catalysts are presented. The former is a manufactured catalyst while the latter is a natural ore. Results suggest that both show satisfying ability for regeneration from carbon deposits. Higher temperature enhances tar decomposition during the experiment with both catalysts. Moreover, the iron-based catalyst enhances the water-gas shift activity, which in turn impacts the total amount of produced gas. On the other hand, the manganese-based catalyst seems to display a higher propensity for tar conversion. (orig.)

  11. Steam reforming of n-hexane on pellet and monolithic catalyst beds. A comparative study on improvements due to heat transfer

    Science.gov (United States)

    1981-01-01

    Monolithic catalysts with higher available active surface areas and better thermal conductivity than conventional pellets beds, making possible the steam reforming of fuels heavier than naphtha, were examined. Performance comparisons were made between conventional pellet beds and honeycomb monolith catalysts using n-hexane as the fuel. Metal-supported monoliths were examined. These offer higher structural stability and higher thermal conductivity than ceramic supports. Data from two metal monoliths of different nickel catalyst loadings were compared to pellets under the same operating conditions. Improved heat transfer and better conversion efficiencies were obtained with the monolith having higher catalyst loading. Surface-gas interaction was observed throughout the length of the monoliths.

  12. Hydrogen Production by Steam Reforming of Ethanol on Rh-Pt Catalysts: Influence of CeO2, ZrO2, and La2O3 as Supports

    Directory of Open Access Journals (Sweden)

    Bernay Cifuentes

    2015-11-01

    Full Text Available CeO2-, ZrO2-, and La2O3-supported Rh-Pt catalysts were tested to assess their ability to catalyze the steam reforming of ethanol (SRE for H2 production. SRE activity tests were performed using EtOH:H2O:N2 (molar ratio 1:3:51 at a gaseous space velocity of 70,600 h−1 between 400 and 700 °C at atmospheric pressure. The SRE stability of the catalysts was tested at 700 °C for 27 h time on stream under the same conditions. RhPt/CeO2, which showed the best performance in the stability test, also produced the highest H2 yield above 600 °C, followed by RhPt/La2O3 and RhPt/ZrO2. The fresh and aged catalysts were characterized by TEM, XPS, and TGA. The higher H2 selectivity of RhPt/CeO2 was ascribed to the formation of small (~5 nm and stable particles probably consistent of Rh-Pt alloys with a Pt surface enrichment. Both metals were oxidized and acted as an almost constant active phase during the stability test owing to strong metal-support interactions, as well as the superior oxygen mobility of the support. The TGA results confirmed the absence of carbonaceous residues in all the aged catalysts.

  13. PdZnAl Catalysts for the Reactions of Water-Gas-Shift, Methanol Steam Reforming, and Reverse-Water-Gas-Shift

    Energy Technology Data Exchange (ETDEWEB)

    Dagle, Robert A.; Platon, Alexandru; Datye, Abhaya K.; Vohs, John M.; Wang, Yong; Palo, Daniel R.

    2008-03-07

    Pd/ZnO/Al2O3 catalysts were studied for water-gas-shift (WGS), methanol steam reforming, and reverse-water-gas-shift (RWGS) reactions. WGS activity was found to be dependent on the Pd:Zn ratio with a maximum activity obtained at approximately 0.50, which was comparable to that of a commercial Pt-based catalyst. The catalyst stability was demonstrated for 100 hours time-on-stream at a temperature of 3600C without evidence of metal sintering. WGS reaction rates were approximately 1st order with respect to CO concentration, and kinetic parameters were determined to be Ea = 58.3 kJ mol-1 and k0 = 6.1x107 min-1. During methanol steam reforming, the CO selectivities were observed to be lower than the calculated equilibrium values over a range of temperatures and steam/carbon ratios studied while the reaction rate constants were approximately of the same magnitude for both WGS and methanol steam reforming. These results indicate that although Pd/ZnO/Al2O3 are active WGS catalysts, WGS is not involved in methanol steam reforming. RWGS rate constants are on the order of about 20 times lower than that of methanol steam reforming, suggesting that RWGS reaction could be one of the sources for small amount of CO formation in methanol steam reforming.

  14. Development of Ni-Based Catalysts Derived from Hydrotalcite-Like Compounds Precursors for Synthesis Gas Production via Methane or Ethanol Reforming

    Directory of Open Access Journals (Sweden)

    Ya-Li Du

    2017-02-01

    Full Text Available As a favorably clean fuel, syngas (synthesis gas production has been the focus of concern in past decades. Substantial literatures reported the syngas production by various catalytic reforming reactions particularly in methane or ethanol reforming. Among the developed catalysts in these reforming processes, Ni-based catalysts from hydrotalcite-like compounds (HTLcs precursors have drawn considerable attention for their preferable structural traits. This review covers the recent literature reporting syngas production with Ni-based catalysts from HTLc precursors via methane or ethanol reforming. The discussion was initiated with catalyst preparation (including conventional and novel means, followed by subsequent thermal treatment processes, then composition design and the addition of promoters in these catalysts. As Ni-based catalysts have thermodynamic potential to deactivate because of carbon deposition or metal sintering, measures for dealing with these problems were finally summarized. To obtain optimal catalytic performances and resultantly better syngas production, based on analyzing the achievements of the references, some perspectives were finally proposed.

  15. Aqueous Phase Glycerol Reforming by PtMo Bimetallic Nano-Particle Catalyst: Product Selectivity and Structural Characterization

    Energy Technology Data Exchange (ETDEWEB)

    Stach E. A.; Dietrich, P.J.; Lobo-Lapidus, R.J.; Wu, T.; Sumer, A.; Akatay, M.C.; Fingland, B.R.; Guo, N.; Dumesic, J.A.; Marshall, C.L.; Jellinek, J.; Delgass, W.N.; Ribeiro, F.H.; Miller, J.T.

    2012-03-01

    A carbon supported PtMo aqueous phase reforming catalyst for producing hydrogen from glycerol was characterized by analysis of the reaction products and pathway, TEM, XPS and XAS spectroscopy. Operando X-ray absorption spectroscopy (XAS) indicates the catalyst consists of bimetallic nano-particles with a Pt rich core and a Mo rich surface. XAS of adsorbed CO indicates that approximately 25% of the surface atoms are Pt. X-ray photoelectron spectroscopy indicates that there is unreduced and partially reduced Mo oxide (MoO{sub 3} and MoO{sub 2}), and Pt-rich PtMo bimetallic nano-particles. The average size measured by transmission electron microscopy of the fresh PtMo nano-particles is about 2 nm, which increases in size to 5 nm after 30 days of glycerol reforming at 31 bar and 503 K. The catalyst structure differs from the most energetically stable structure predicted by density functional theory (DFT) calculations for metallic Pt and Mo atoms. However, DFT indicates that for nano-particles composed of metallic Pt and Mo oxide, the Mo oxide is at the particle surface. Subsequent reduction would lead to the experimentally observed structure. The aqueous phase reforming reaction products and intermediates are consistent with both C-C and C-OH bond cleavage to generate H{sub 2}/CO{sub 2} or the side product CH{sub 4}. While the H{sub 2} selectivity at low conversion is about 75%, cleavage of C-OH bonds leads to liquid products with saturated carbon atoms. At high conversions (to gas), these will produced additional CH{sub 4} reducing the H{sub 2} yield and selectivity.

  16. Surface Reaction Kinetics of Steam- and CO2-Reforming as Well as Oxidation of Methane over Nickel-Based Catalysts

    Directory of Open Access Journals (Sweden)

    Karla Herrera Delgado

    2015-05-01

    Full Text Available An experimental and kinetic modeling study on the Ni-catalyzed conversion of methane under oxidative and reforming conditions is presented. The numerical model is based on a surface reaction mechanism consisting of 52 elementary-step like reactions with 14 surface and six gas-phase species. Reactions for the conversion of methane with oxygen, steam, and CO2 as well as methanation, water-gas shift reaction and carbon formation via Boudouard reaction are included. The mechanism is implemented in a one-dimensional flow field description of a fixed bed reactor. The model is evaluated by comparison of numerical simulations with data derived from isothermal experiments in a flow reactor over a powdered nickel-based catalyst using varying inlet gas compositions and operating temperatures. Furthermore, the influence of hydrogen and water as co-feed on methane dry reforming with CO2 is also investigated.

  17. Application of nickel nanoparticles as catalyst in the viscosity reduction of Venezuelan atmospheric residues by water reformation

    Energy Technology Data Exchange (ETDEWEB)

    Golindano, T.; Martinez, S.; Pimentel, M.; Segovia, X.; Pena, J.P.; Sanchez, R.; Sardella, R. [PDVSA Petroleos de Venezuela SA, Caracas (Venezuela, Bolivarian Republic of). INTEVEP Dept. of Residue and Heavy Crude Processing; Canizales, E. [PDVSA Petroleos de Venezuela SA, Caracas (Venezuela, Bolivarian Republic of). INTEVEP Dept. of Analytics

    2009-07-01

    A catalytic upgrading process for extra-heavy crude oil was presented. Nickel nanoparticles were combined with transition metals and used as a catalyst for a water reformation process used to reduce oil viscosity. Thermal and catalytic process experiments were conducted in order to determine the catalytic activity of the nanoparticles. The nanoparticles were dispersed in gasoil in order to promote better interactions between the heavy feeds and the catalyst. The nanoparticles were characterized using transmission electron microscopy (TEM) and chemical analyses. The study showed that the nanoparticles increased the conversion rate from 14.6 p/p to 37.4 p/p. Bottom products generated by the catalytic process were of higher quality than products produced using thermal processing techniques. It was concluded that the nanostructured materials diminished the viscosity of the atmospheric residue. 5 refs., 6 tabs., 3 figs.

  18. Hydrogen production from raw bioethanol steam reforming: Optimization of catalyst composition with improved stability against various impurities

    Energy Technology Data Exchange (ETDEWEB)

    Le Valant, Anthony; Can, Fabien; Bion, Nicolas; Duprez, Daniel; Epron, Florence [Laboratoire de Catalyse en Chimie organique, UMR6503 CNRS, Universite de Poitiers, 40 avenue du recteur Pineau, 86022 Poitiers Cedex (France)

    2010-05-15

    The use of raw bioethanol is of major importance for a cost effective industrial application. Raw bioethanol contains higher alcohols as the main impurities and also aldehydes, amines, acids and esters. The effect of these impurities on the catalytic performances for ethanol steam reforming (ESR) has been studied, using a reference catalyst, Rh/MgAl{sub 2}O{sub 4}. It was shown that the aldehyde, the amine and methanol have no negative effect on the catalytic performances, contrary to the ester, acid and higher alcohols. The deactivation is mainly explained by coke formation favored by the presence of these impurities in the feed. In order to improve the stability of the catalyst and its performances in the presence of these deactivating impurities, the catalyst formulation, i.e. the composition of the support and of the metallic phase, was modified. The addition of rare earth elements instead of magnesium to the alumina support leads to a decrease of the strong and medium acid sites and to an increase of the basicity. On these modified supports, the dehydration reaction, leading to olefins, which are coke precursors, is disfavored, the ethanol conversion and the hydrogen yield are increased. The best catalytic performances were obtained with Rh/Y-Al{sub 2}O{sub 3}. Then, the metallic phase was also modified by adding a second metal (Ni, Pt or Pd). The Rh-Ni/Y-Al{sub 2}O{sub 3} catalyst leads to the highest hydrogen yield. This catalyst, tested in the presence of raw bioethanol during 24 h was very stable compared to the reference catalyst Rh/MgAl{sub 2}O{sub 4}, which was strongly deactivated after 2 h of time-on -stream. (author)

  19. CuO/ZnO catalysts for methanol steam reforming: The role of the support polarity ratio and surface area

    OpenAIRE

    2015-01-01

    The effect of surface area and polarity ratio of ZnO support on the catalytic properties of CuO/ZnO catalyst for methanol steam reforming (MSR) are studied. The surface area of ZnO was varied changing the calcination temperature and its polarity ratio was modified using different Zn precursors, zinc acetate and zinc nitrate. It was found that the copper dispersion and copper surface area increase with the surface area of the ZnO support and the polarity ratio of ZnO strongly in...

  20. Autothermal Reforming and Partial Oxidation of Methane in Fluidized Reactor over Highly Dispersed Ni Catalyst Prepared from Ni Complex

    Institute of Scientific and Technical Information of China (English)

    GAO Jing; HOU Zhao-Yin; SHEN Kai; LOU Hui; FEI Jin-Hua; ZHENG Xiao-Ming

    2006-01-01

    Highly dispersed Ni catalysts on spherical SiO2 were prepared by simple impregnation of Ni(acac)2, [Ni-(NH3)6-n(H2O)n]2+, [Ni(en)3]2+ and [Ni(EDTA)]2-. Pulse adsorption of H2 and TEM analysis results confirmed that Ni was dispersed very well on the surface of SiO2 even after calcination (4 h) and reduction (1 h) at high temperature of 800 ℃. These highly dispersed and uniquely sized Ni crystallites were more stable and more reactive for both autothermal reforming and partial oxidation of methane in fluidized reactor.

  1. Hydrogen production by ethanol steam reforming over Cu-Ni/SBA-15 supported catalysts prepared by direct synthesis and impregnation

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-07-31

    Cu-Ni/SBA-15 supported catalysts prepared by the incipient wetness impregnation method were tested in the ethanol steam reforming reaction for hydrogen production. The effect of reaction temperature and metal loading was studied in order to maximize the hydrogen selectivity and the CO{sub 2}/(CO + CO{sub 2}) molar ratio. The best catalytic performance was achieved at 600 C. Products distribution was the result of the combined effects of metal particles size, metal content and Ni/Cu ratio on the catalyst. In addition, two catalysts were prepared by the method of direct insertion of Ni and Cu in the initial stage of the SBA-15 synthesis. X-ray powder diffraction (XRD), transmission electron microscopy (TEM), N{sub 2}- adsorption and inductively coupled plasma atomic emission spectroscopy (ICP-AES) results evidenced that SBA-15 materials with long range hexagonal ordering were successfully synthesized in the presence of copper and nickel salts with the (Cu + Ni) contents around 4-6 wt.%. However, lower hydrogen selectivity as well as ethanol and water conversions were obtained with catalysts prepared by direct synthesis in comparison with those prepared by incipient wetness impregnation method. Particularly, the best catalytic results were achieved with a sample impregnated with 2 and 7 wt.% of copper and nickel, respectively. (author)

  2. Catalytic activity and effect of modifiers on Ni-based catalysts for the dry reforming of methane

    Energy Technology Data Exchange (ETDEWEB)

    Barroso-Quiroga, Maria Martha; Castro-Luna, Adolfo Eduardo [Facultad de Ingenieria y Ciencias Economico-Sociales INTEQUI-CONICET-UNSL, Av. 25 de Mayo 384 (5730) Villa Mercedes (S.L.) (Argentina)

    2010-06-15

    Ni catalysts supported on different ceramic oxides (Al{sub 2}O{sub 3}, CeO{sub 2}, La{sub 2}O{sub 3}, ZrO{sub 2}) were prepared by wet impregnation. The catalytic behavior toward hydrogen production through the dry reforming of methane using a fixed-bed reactor was evaluated under certain experimental conditions, and the catalyst supported on ZrO{sub 2} showed the highest stable activity during the period of time studied. The catalyst supported on CeO{sub 2} has a relatively good activity, but shows signs of deactivation after a certain time during the reaction. This catalyst was chosen to be studied after the addition of 0.5 wt% Li and K as activity modifiers. The introduction of the alkaline metals produces a reduction of the catalytic activity but a better stability over the reactant conversion time. The reverse water-gas shift reaction influences the global system of reactions, and as the results indicate, should be considered near equilibrium. (author)

  3. Preparation of Uniform Ni-B Amorphous Alloy Catalyst on CNTs and its Performance for Acetylene Selective Hydrogenation

    Institute of Scientific and Technical Information of China (English)

    Chang Yuan HU; Feng Yi LI; Rong Bin ZHANG; Li HUA

    2006-01-01

    Uniform Ni-B amorphous alloys about 14 nm have been prepared on CNTs-A support,named Ni-B/CNTs-A. In comparison with the Ni-B/CNTs amorphous catalyst, Ni-B/CNTs-A showed higher nickel loading, determined by ICP and better catalytic activity and ethylene selectivity in the acetylene hydrogenation reaction.

  4. Hydrogen Production by Steam Reforming of Liquefied Natural Gas (LNG) Over Nickel-Phosphorus-Alumina Xerogel Catalyst Prepared by a Carbon-Templating Epoxide-Driven Sol-Gel Method.

    Science.gov (United States)

    Bang, Yongju; Park, Seungwon; Han, Seung Ju; Yoo, Jaekyeong; Choi, Jung Ho; Kang, Tae Hun; Lee, Jinwon; Song, In Kyu

    2016-05-01

    A nickel-phosphorus-alumina xerogel catalyst was prepared by a carbon-templating epoxide-driven sol-gel method (denoted as CNPA catalyst), and it was applied to the hydrogen production by steam reforming of liquefied natural gas (LNG). For comparison, a nickel-phosphorus-alumina xerogel catalyst was also prepared by a similar method in the absence of carbon template (denoted as NPA catalyst). The effect of carbon template addition on the physicochemical properties and catalytic activities of the catalysts in the steam reforming of LNG was investigated. Both CNPA and NPA catalysts showed excellent textural properties with well-developed mesoporous structure. However, CNPA catalyst retained a more reducible nickel aluminate phase than NPA catalyst. XRD analysis of the reduced CNPA and NPA catalysts revealed that nickel sintering on the CNPA catalyst was suppressed compared to that on the NPA catalyst. From H2-TPD and CH4-TPD measurements of the reduced CNPA and NPA catalysts, it was also revealed that CNPA catalyst with large amount of hydrogen uptake and strong hydrogen-binding sites showed larger amount of methane adsorption than NPA catalyst. In the hydrogen production by steam reforming of LNG, CNPA catalyst with large methane adsorption capacity showed a better catalytic activity than NPA catalyst.

  5. Low CO content hydrogen production from oxidative steam reforming of ethanol over CuO-CeO2 catalysts at low-temperature

    Institute of Scientific and Technical Information of China (English)

    Xue; Han; Yunbo; Yu; Hong; He; Jiaojiao; Zhao

    2013-01-01

    CuO-CeO2 catalysts were prepared by a urea precipitation method for the oxidative steam reforming of ethanol at low-temperature.The catalytic performance was evaluated and the catalysts were characterized by inductively coupled plasma atomic emission spectroscopy,X-ray diffraction,temperature-programmed reduction,field emission scanning electron microscopy and thermo-gravimetric analysis.Over CuOCeO2 catalysts,H2 with low CO content was produced in the whole tested temperature range of 250–450 C.The non-noble metal catalyst 20CuCe showed higher H2production rate than 1%Rh/CeO2 catalyst at 300–400 C and the advantage was more obvious after 20 h testing at400 C.These results further confirmed that CuO-CeO2 catalysts may be suitable candidates for low temperature hydrogen production from ethanol.

  6. A Phenomenological Study on the Synergistic Role of Precious Metals in the Steam Reforming of Logistic Fuels on Bimetal-Supported Catalysts

    Directory of Open Access Journals (Sweden)

    Abdul-Majeed Azad

    2011-01-01

    Full Text Available Fuel processors are required to convert sulfur-laden logistic fuels into hydrogen-rich reformate and deliver to the fuel cell stack with little or no sulfur. Since sulfur poisons and deactivates the reforming catalyst, robust sulfur-tolerant catalysts ought to be developed. In this paper, the development, characterization and evaluation of a series of reforming catalysts containing two noble metals (with total metal loading not exceeding 1 weight percent supported on nanoscale ceria for the steam-reforming of kerosene is reported. Due to inherent synergy, a bimetallic catalyst is superior to its monometallic analog, for the same level of loading. The choice of noble metal combination in the bimetallic formulations plays a vital and meaningful role in their performance. Presence of ruthenium and/or rhodium in formulations containing palladium showed improved sulfur tolerance and significant enhancement in their catalytic activity and stability. Rhodium was responsible for higher hydrogen yields in the logistic fuel reformate. Duration of steady hydrogen production was higher in the case of RhPd (75 h than for RuPd (68 h; hydrogen generation was stable over the longest period (88 h with RuRh containing no Pd. A mechanistic correlation between the characteristic role of precious metals in the presence of each other is discussed.

  7. 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

  8. Catalytic Steam Reforming of Toluene as a Model Compound of Biomass Gasification Tar Using Ni-CeO2/SBA-15 Catalysts

    Directory of Open Access Journals (Sweden)

    Erik Dahlquist

    2013-07-01

    Full Text Available Nickel supported on SBA-15 doped with CeO2 catalysts (Ni-CeO2/SBA-15 was prepared, and used for steam reforming of toluene which was selected as a model compound of biomass gasification tar. A fixed-bed lab-scale set was designed and employed to evaluate the catalytic performances of the Ni-CeO2/SBA-15 catalysts. Experiments were performed to reveal the effects of several factors on the toluene conversion and product gas composition, including the reaction temperature, steam/carbon (S/C ratio, and CeO2 loading content. Moreover, the catalysts were subjected to analysis of their carbon contents after the steam reforming experiments, as well as to test the catalytic stability over a long experimental period. The results indicated that the Ni-CeO2/SBA-15 catalysts exhibited promising capabilities on the toluene conversion, anti-coke deposition and catalytic stability. The toluene conversion reached as high as 98.9% at steam reforming temperature of 850 °C and S/C ratio of 3 using the Ni-CeO2(3wt%/SBA-15 catalyst. Negligible coke formation was detected on the used catalyst. The gaseous products mainly consisted of H2 and CO, together with a little CO2 and CH4.

  9. Pd-Au bimetallic catalysts: understanding alloy effects from planar models and (supported) nanoparticles.

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Feng; Goodman, Wayne D.

    2012-12-21

    Pd-Au bimetallic catalysts often display enhanced catalytic activities and selectivities compared with Pd-alone catalysts. This enhancement is often caused by two alloy effects, i.e., ensemble and ligand effects. The ensemble effect is dilution of surface Pd by Au. With increasing surface Au coverages, contiguous Pd ensembles disappear and isolated Pd ensembles form. For certain reactions, for example vinyl acetate synthesis, this effect is responsible for reaction rate enhancement via the formation of highly active surface sites, e.g., isolated Pd pairs. The disappearance of contiguous Pd ensembles also switches off side reactions catalyzed by these sites. This explains selectivity increase of certain reactions, for example direct H2O2 synthesis. The ligand effect is electronic perturbation of Au to Pd. By direct charge transfer or affecting bond length, the ligand effect causes the Pd d band to be more filled and the d-band center away from the Fermi level. Both changes make Pd more "atomic like" therefore binding reactants and products weaker. For certain reactions, this eliminates the so-called "self poisoning" and enhances activity/selectivity.

  10. Hydrogen production for fuel cells by autothermal reforming of methane over sulfide nickel catalyst on a gamma alumina support

    Science.gov (United States)

    Hoang, D. L.; Chan, S. H.; Ding, O. L.

    Experimental and modelling studies have been conducted on catalytic autothermal reforming (ATR) of methane for hydrogen production over a sulfide nickel catalyst on a gamma alumina support. The experiments are performed with different feedstock under thermally neutral conditions. The results show that the performance of the reformer is dependent on the molar air-to-fuel ratio (A/F), the molar water-to-fuel ratio (W/F) and the flowrate of the feedstock mixture. The optimum conditions for high methane conversion and high hydrogen yield are A/F = 3-3.5, W/F = 2-2.5 and a fuel flowrate below 120-250 l h -1. Under these conditions, a methane conversion of 95-99% and a hydrogen yield of 39-41% on a dry basis can be achieved and 1 mole of methane can produce 1.8 moles of hydrogen at an equilibrium reactor temperature of not exceeding 850 °C. A two-dimensional reactor model is developed to simulate the conversion behaviour of the reactor for further study of the reforming process. The model includes all aspects of the major chemical kinetics and the heat and mass transfer phenomena in the reactor. The predicted results are successfully validated with experimental data.

  11. Hydriding/dehydriding properties of NdMgNi alloy with catalyst CeO2

    Institute of Scientific and Technical Information of China (English)

    李霞; 张羊换; 杨泰; 许剑轶; 赵栋梁

    2016-01-01

    Hydrogen storage composites Nd2Mg17-50 wt.%Ni-x wt.%CeO2 (x=0, 0.5, 1.0, 1.5, 2.0) were obtained by induction-ball milling method. The catalytic effect of CeO2 on hydriding kinetics of Nd2Mg17-50 wt.%Ni composite was investigated. X-ray diffrac-tion (XRD) and high resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED) analyses showed that Nd2Mg17-50 wt.%Ni alloy had a multiphase structure, consisting of NdMg12, NdMg2Ni, Mg2Ni and Ni phases and the addition of catalyst CeO2 prompted the composites to be partly transformed into amorphous strucutre. The CeO2 improved the maxi-mum hydrogen capacity of Nd2Mg17-50 wt.%Ni alloy from 3.192 wt.% to 3.376 wt.% (x=1.0). What’s more, the increment of diffu-sion coefficientD led to the faster hydriding kinetics, which was calculated by Avrami-Erofeev equation. The dehydrogenation tem-perature reduced from 515.54 to 504.72 K was mainly caused by the decrease of activation energy from 93.28 to 69.36 kJ/mol, which was proved by the Kissinger equation.

  12. Catalytic Performance and Characterization of Pt-Co/Al2O3Catalysts for CO2 Reforming of CH4 to Synthesis Gas

    Institute of Scientific and Technical Information of China (English)

    HUANG, Chuan-Jing; ZHENG, Xiao-Ming; MO, Liu-Ye; FEI, Jin-Hua

    2001-01-01

    Pt-Co/Al2O3 catalyst has been studied for CO2 reforming of CH4 to synthesis gas. It was found that the catalytic performance of the catalyst was sensitive to calcination temperature.When Co/Al2O3 was calcined at 1473 K prior to adding a small amount of Pt to it, the resulting bimetallic catalyst showed high activity, optimal stability and excellent resistance to carbon deposition, which was more effective to the reaction than Co/Al2O3 and Pt/Al2O3 catalysts. At lower metal loading, catalyst activity decreased in the following order: Pt-Co/Al2O3 > Pt/Al2O3 》 Co/Al2O3. With 9% Co, the Co/Al2O3calcined at 923 K was also active for CO2 reforming of CH4,however, its carbon formation was much more fast than that of the Pt-Co/Al2O3 catalyst. The XRD results indicated that Pt species well dispersed over the bimetallic catalyst. Its high dispersion was related to the presence of CoAl2O4, formed during calcining of Co/Al2O3 at high temperature before Pt addition. Promoted by Pt, CoAl2O4 in the catalyst could be reduced partially even at 923 K, the temperature of pre-re-duction for the reaction, confirmed by TPR. Based on these results, it was considered that the zerovalent platinum with high dispersion over the catalyst surface and the zerovalent cobalt resulting from CoAl2O4 reduction are responsible for high activity of the Pt-Co/Al2O3 catalyst, and the remain CoAl2O4 is beneficial to suppression of carbon deposition over the catalyst.

  13. Ni-SiO₂ catalysts for the carbon dioxide reforming of methane: varying support properties by flame spray pyrolysis.

    Science.gov (United States)

    Lovell, Emma C; Scott, Jason; Amal, Rose

    2015-01-01

    Silica particles were prepared by flame spray pyrolysis (FSP) as a support for nickel catalysts. The impact of precursor feed rate (3, 5 and 7 mL/min) during FSP on the silica characteristics and the ensuing effect on catalytic performance for the carbon dioxide, or dry, reforming of methane (DRM) was probed. Increasing the precursor feed rate: (i) progressively lowered the silica surface area from ≈340 m2/g to ≈240 m2/g; (ii) altered the silanol groups on the silica surface; and (iii) introduced residual carbon-based surface species to the sample at the highest feed rate. The variations in silica properties altered the (5 wt %) nickel deposit characteristics which in turn impacted on the DRM reaction. As the silica surface area increased, the nickel dispersion increased which improved catalyst performance. The residual carbon-based species also appeared to improve nickel dispersion, and in turn catalyst activity, although not to the same extent as the change in silica surface area. The findings illustrate both the importance of silica support characteristics on the catalytic performance of nickel for the DRM reaction and the capacity for using FSP to control these characteristics.

  14. Ni-SiO2 Catalysts for the Carbon Dioxide Reforming of Methane: Varying Support Properties by Flame Spray Pyrolysis

    Directory of Open Access Journals (Sweden)

    Emma C. Lovell

    2015-03-01

    Full Text Available Silica particles were prepared by flame spray pyrolysis (FSP as a support for nickel catalysts. The impact of precursor feed rate (3, 5 and 7 mL/min during FSP on the silica characteristics and the ensuing effect on catalytic performance for the carbon dioxide, or dry, reforming of methane (DRM was probed. Increasing the precursor feed rate: (i progressively lowered the silica surface area from ≈340 m2/g to ≈240 m2/g; (ii altered the silanol groups on the silica surface; and (iii introduced residual carbon-based surface species to the sample at the highest feed rate. The variations in silica properties altered the (5 wt % nickel deposit characteristics which in turn impacted on the DRM reaction. As the silica surface area increased, the nickel dispersion increased which improved catalyst performance. The residual carbon-based species also appeared to improve nickel dispersion, and in turn catalyst activity, although not to the same extent as the change in silica surface area. The findings illustrate both the importance of silica support characteristics on the catalytic performance of nickel for the DRM reaction and the capacity for using FSP to control these characteristics.

  15. Ni/MgO catalyst prepared using atmospheric high-frequency discharge plasma for CO2 reforming of methane

    Institute of Scientific and Technical Information of China (English)

    Pan Qin; Huiyuan Xu; Huali Long; Yi Ran; Shuyong Shang; Yongxiang Yin; Xiaoyan Dai

    2011-01-01

    A new type of Ni/MgO catalyst was prepared using atmospheric high-frequency discharge cold plasma.The influences of conventional method,plasma method,and plasma plus calcination method on the catalytic activity were studied and the CO2 reforming of methane was chosen as the probe reaction.The catalysts were characterized by X-ray diffraction (XRD),transmission electron microscope (TEM),X-ray photoelectron spectroscopy,and CO2 temperature-programmed surface reaction techniques.The results suggested that the nickel-based catalyst prepared by plasma plus calcination method possessed a smaller particle size and a higher dispersion of active component,better low-temperature activity and enhanced anti-coking ability.The conversion of CO2 and CH4 was 90.70% and 89.37%,respectively,and the reaction lasted for 36 h without obvious deactivation under 101.325 kPa and 750 ℃ with CO2/CH4 =1/1.

  16. Steam reforming of biomass tar producing H2-rich gases over Ni/MgOx/CaO1-x catalyst.

    Science.gov (United States)

    Li, Chunshan; Hirabayashi, Daisuke; Suzuki, Kenzi

    2010-01-01

    Series nickel catalysts Ni/MgO(x)/CaO(1-)(x) (x=0.3, 0.5, 0.7, Ni: 5 wt%) were prepared and tested in fixed-bed reactor for biomass tar steam reforming, toluene as tar destruction model compound. Different ratios of MgO and CaO were mixed to simulate dolomite as Ni support. Two preparation methods: solid mixing with (SMW) and without water (SM) were used, the preparation methods and concentration of MgO had an important influence on toluene conversion and products. Catalysts prepared by SM method exhibited higher performance on toluene conversion, resulted in higher H(2) yield, and also, higher CO(2) and lower CO selectivity with higher temperature. For the same preparation method, higher concentration of MgO resulted in higher toluene conversion, and also influence on CO, CO(2) selectivity, but no obvious influence on the H(2) yield. Catalysts were characterized by BET, X-ray diffraction (XRD), SEM.

  17. PREPARATION AND CHARACTERIZATION OF SPHERICAL PP/PB ALLOYS WITH MgCl2-SUPPORTED ZIEGLER-NATTA CATALYST

    Institute of Scientific and Technical Information of China (English)

    Ai-hua He; Yang-wei Shi; Guo-qing Liu; Wei Yao; Bao-chen Huang

    2012-01-01

    Polypropylene (PP)/polybutene-1 (PB) alloys within reactor were prepared by MgCl2-supported Ziegler-Natta catalyst with sequential two-stage polymerization technology.First,propylene homo-polymerizations were carried out to form isotactic polypropylene (iPP) particles containing active catalyst.Then,butene-1 was subsequently polymerized to form polybutene-1 phase inside the iPP particles.Finally,iPP/PB alloys with spherical shape and adjustable PB content were synthesized.The catalytic activity and catalytic stereospecificity of the Z-N catalyst in the two-stage polymerization process are discussed.The composition and physical properties of the PP alloys were characterized by FT-IR,13C-NMR,SEM,DSC and XRD.It was found that the in-reactor PP alloys are mainly composed of PP and PB with a little amount of poly(buteneco-propylene) random copolymers and poly(butene-block-propylene) block copolymers.SEM measurements verified that the PB phases with size in the range of 300-400 nm dispersed in the PP matrix uniformly.The incorporation of PB upon the PP matrix affects the properties of final products greatly.

  18. Analysis of Deactivation Mechanism on a Multi-Component Sulfur-Tolerant Steam Reforming Catalyst

    Science.gov (United States)

    2010-08-01

    298 = -41 kJ/mol 3.2 While steam reforming is highly endothermic , water gas shift is moderately exothermic . The steam reforming is favored at...40 2.4.1. Definition of hydrogen yield ......................................................................... 41 xii...3H2 + CO ΔH o 298 = +206 kJ/mol 1.1 Water gas shift CO + H2O H2 + CO2 ΔH o 298 = -41 kJ/mol 1.2 The reforming reaction is endothermic and external

  19. Ni/SiO2 Catalyst Prepared with Nickel Nitrate Precursor for Combination of CO2 Reforming and Partial Oxidation of Methane: Characterization and Deactivation Mechanism Investigation

    OpenAIRE

    Sufang He; Lei Zhang; Suyun He; Liuye Mo; Xiaoming Zheng; Hua Wang; Yongming Luo

    2015-01-01

    The performance of Ni/SiO2 catalyst in the process of combination of CO2 reforming and partial oxidation of methane to produce syngas was studied. The Ni/SiO2 catalysts were prepared by using incipient wetness impregnation method with nickel nitrate as a precursor and characterized by FT-IR, TG-DTA, UV-Raman, XRD, TEM, and H2-TPR. The metal nickel particles with the average size of 37.5 nm were highly dispersed over the catalyst, while the interaction between nickel particles and SiO2 support...

  20. Renewable H2 from glycerol steam reforming: effect of La2O3 and CeO2 addition to Pt/Al2O3 catalysts.

    Science.gov (United States)

    Montini, Tiziano; Singh, Rakesh; Das, Piyali; Lorenzut, Barbara; Bertero, Nicolás; Riello, Pietro; Benedetti, Alvise; Giambastiani, Giuliano; Bianchini, Claudio; Zinoviev, Sergey; Miertus, Stanislav; Fornasiero, Paolo

    2010-05-25

    Glycerol is the main byproduct of biodiesel production and its increased production volume derives from the increasing demand for biofuels. The conversion of glycerol to hydrogen-rich mixtures presents an attractive route towards sustainable biodiesel production. Here we explored the use of Pt/Al(2)O(3)-based catalysts for the catalytic steam reforming of glycerol, evidencing the influence of La(2)O(3) and CeO(2) doping on the catalyst activity and selectivity. The addition of the latter metal oxides to a Pt/Al(2)O(3) catalyst is found to significantly improve the glycerol steam reforming, with high H(2) and CO(2) selectivities. A good catalytic stability is achieved for the Pt/La(2)O(3)/Al(2)O(3) system working at 350 degrees C, while the Pt/CeO(2)/Al(2)O(3) catalyst sharply deactivates after 20 h under similar conditions. Studies carried out on fresh and exhausted catalysts reveal that both systems maintain high surface areas and high Pt dispersions. Therefore, the observed catalyst deactivation can be attributed to coke deposition on the active sites throughout the catalytic process and only marginally to Pt nanoparticle sintering. This work suggests that an appropriate support composition is mandatory for preparing high-performance Pt-based catalysts for the sustainable conversion of glycerol into syngas.

  1. Preparation of carbon alloy catalysts for polymer electrolyte fuel cells from nitrogen-containing rigid-rod polymers

    Energy Technology Data Exchange (ETDEWEB)

    Chokai, Masayuki [Department of Organic and Polymeric Materials, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo 152-8552 (Japan); Integrative Technology Research Institute, Teijin Ltd., 4-3-2, Asahigaoka, Hino, Tokyo 191-8512 (Japan); Taniguchi, Masataka; Shinoda, Tsuyoshi; Nabae, Yuta; Kuroki, Shigeki; Hayakawa, Teruaki; Kakimoto, Masa-aki [Department of Organic and Polymeric Materials, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo 152-8552 (Japan); Moriya, Shogo; Matsubayashi, Katsuyuki [Department of Organic and Polymeric Materials, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo 152-8552 (Japan); Business Development Division, Nisshinbo Holdings, Inc., 1-2-3, Onodai, Midori-ku, Chiba 267-0056 (Japan); Ozaki, Jun-ichi [Department of Organic and Polymeric Materials, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo 152-8552 (Japan); Department of Nanomaterial Systems, Graduate School of Engineering, Gunma University, 1-5-1, Tenjin-cho, Kiryu, Gunma 376-8515 (Japan); Miyata, Seizo [Department of Organic and Polymeric Materials, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo 152-8552 (Japan); New Energy and Industrial Technology Development Organization, 1310 Omiya-cho, Saiwai-ku, Kawasaki, Kanagawa 212-8554 (Japan)

    2010-09-15

    Carbon alloy catalysts (CAC), non-precious metal catalysts for the oxygen reduction reaction (ORR), were prepared from various kinds of nitrogen-containing rigid-rod aromatic polymers, polyimides, polyamides and azoles, by carbonization at 900 C under nitrogen flow. The catalytic activity for ORR was evaluated by the onset potential, which was taken at a current density of -2 {mu}A cm{sup -2}. Carbonized polymers having high nitrogen content showed higher onset potential. In particular, CACs derived from azole (Az5) had an onset potential of 0.8 V, despite being was prepared without any metals. (author)

  2. Effects of sol-gel method and lanthanum addition on catalytic performances of nickel-based catalysts for methane reforming with carbon dioxide

    Institute of Scientific and Technical Information of China (English)

    LI Xiancai; HU Quanhong; YANG Yifeng; CHEN Juanrong; LAI Zhihua

    2008-01-01

    The nickel-based catalysts were prepared by the sol-gel method and used for the CH4 reforming with CO2. The effects of the sol-gel method on the specific surface area, catalytic activity, desorption, and reduction performances of catalysts were investigated with BET, TPR, and TPD. Compared with the catalyst prepared by the impregnation method, the results indicated that the catalysts prepared by the sol-gel method had larger specific surface area, showing higher catalytic activities and exhibiting perfect desorption and reduction per-formances. In addition, the modification effects of adding La were studied, and it was found that the 0.75NLBT catalyst constituted of 5wt.%Ni-0.75wt.%La was optimal.

  3. Dry reforming reaction over nickel catalysts supported on nanocrystalline calcium aluminates with different CaO/Al2O3 ratios

    Institute of Scientific and Technical Information of China (English)

    Atiyeh Ranjbar; Mehran Rezaei

    2012-01-01

    Nanocrystalline calcium aluminates with different CaO/Al2O3 ratios were prepared by a facile co-precipitation method using Poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (PEG-PPG-PEG,MW:5800) as a surfactant.They were employed as catalyst support for nickel catalysts in methane reforming with carbon dioxide.The prepared samples were characterized by X-ray diffraction (XRD),N2 adsorption (BET),temperature-programmed reduction and oxidation (TPR-TPO),and scanning electron microscopy (SEM) techniques.Catalysts showed a relatively high catalytic activity and stability.TPR analysis revealed that the catalysts with higher CaO content are more difficult to be reduced.TPO analysis showed that the 5 wt%Ni/CA and 5 wt%Ni/C 12A7 catalysts with higher CaO amount were effective against coke deposition.

  4. Performance of Co/MgO catalyst for CO2 reforming of toluene as a model compound of tar derived from biomass gasification

    Institute of Scientific and Technical Information of China (English)

    Xiuxiu Bao; Meng Kong; Wen Lu; Jinhua Fei∗; Xiaoming Zheng

    2014-01-01

    Catalytic performances of the CO2 reforming of toluene on Co/MgO catalysts with different cobalt loadings were evaluated in a fluidized-bed reactor. The results showed that the conversion of toluene and the stability of Co/MgO increased, but the apparent reaction rate decreased at the initial stage with increasing the amount of metallic Co formed from the reduction of Co/MgO catalysts at 700◦C. The deactivation of Co/MgO catalysts was mainly resulted from that a part of the metallic Co was oxidized by CO2 and could not be re-reduced by H2 at reaction temperature. Therefore, the excess metallic Co on the higher Co loading catalysts was beneficial to the catalyst stability.

  5. A Phenomenological Study on the Synergistic Role of Precious Metals and the Support in the Steam Reforming of Logistic Fuels on Monometal Supported Catalysts

    Directory of Open Access Journals (Sweden)

    Abdul-Majeed Azad

    2010-01-01

    Full Text Available Clean power source utilizing vast logistic fuel reserves (jet fuels, diesel, and coal would be the main driver in the 21st century for high efficiency. Fuel processors are required to convert these fuels into hydrogen-rich reformate for extended periods in the presence of sulfur, and deliver hydrogen with little or no sulfur to the fuel cell stack. However, the jet and other logistic fuels are invariably sulfur-laden. Sulfur poisons and deactivates the reforming catalyst and therefore, to facilitate continuous uninterrupted operation of logistic fuel processors, robust sulfur-tolerant catalysts ought to be developed. New noble metal-supported ceria-based sulfur-tolerant nanocatalysts were developed and thoroughly characterized. In this paper, the performance of single metal-supported catalysts in the steam-reforming of kerosene, with 260 ppm sulfur is highlighted. It was found that ruthenium-based formulation provided an excellent balance between hydrogen production and stability towards sulfur, while palladium-based catalyst exhibited rapid and steady deactivation due to the highest propensity to sulfur poisoning. The rhodium supported system was found to be most attractive in terms of high hydrogen yield and long-term stability. A mechanistic correlation between the role of the nature of the precious metal and the support for generating clean desulfurized H2-rich reformate is discussed.

  6. Hydrogen-Rich Gas Production by Sorption Enhanced Steam Reforming of Woodgas Containing TAR over a Commercial Ni Catalyst and Calcined Dolomite as CO2 Sorbent

    Directory of Open Access Journals (Sweden)

    Vincenzo Naso

    2013-07-01

    Full Text Available The aim of this work was the evaluation of the catalytic steam reforming of a gaseous fuel obtained by steam biomass gasification to convert topping atmosphere residue (TAR and CH4 and to produce pure H2 by means of a CO2 sorbent. This experimental work deals with the demonstration of the practical feasibility of such concepts, using a real woodgas obtained from fluidized bed steam gasification of hazelnut shells. This study evaluates the use of a commercial Ni catalyst and calcined dolomite (CaO/MgO. The bed material simultaneously acts as reforming catalyst and CO2 sorbent. The experimental investigations have been carried out in a fixed bed micro-reactor rig using a slipstream from the gasifier to evaluate gas cleaning and upgrading options. The reforming/sorption tests were carried out at 650 °C while regeneration of the sorbent was carried out at 850 °C in a nitrogen environment. Both combinations of catalyst and sorbent are very effective in TAR and CH4 removal, with conversions near 100%, while the simultaneous CO2 sorption effectively enhances the water gas shift reaction producing a gas with a hydrogen volume fraction of over 90%. Multicycle tests of reforming/CO2 capture and regeneration were performed to verify the stability of the catalysts and sorbents to remove TAR and capture CO2 during the duty cycle.

  7. OXIDATIVE-REFORMING OF METHANE AND PARTIAL OXIDATION OF METHANE REACTIONS OVER NiO/PrO2/ZrO2 CATALYSTS: EFFECT OF NICKEL CONTENT

    Directory of Open Access Journals (Sweden)

    Y. J. O. Asencios

    Full Text Available Abstract In this work the behavior of NiO-PrO2-ZrO2 catalysts containing various nickel loadings was evaluated in the partial oxidation of methane and oxidative-reforming reactions of methane. The catalysts were characterized by X-Ray Diffraction Analysis (in situ-XRD, Temperature Programmed Reduction (H2-TPR, Scanning Electron Microscopy (SEM/EDX and Adsorption-Desorption of nitrogen (BET area. The reactions were carried out at 750 °C and 1 atm for 5 hours. The catalysts were studied with different nickel content: 0, 5, 10 and 15% (related to total weight of catalyst, wt%. In both reactions, the catalyst containing the mixture of the three oxides (NiO/PrO2/ZrO2 with 15% nickel (15NiPrZr catalyst showed the best activity for the conversion of the reactants into Syngas and showed high selectivity for H2 and CO. The results suggest that the promoter PrO2 and the Niº centers are in a good proportion in the catalyst with 15% Ni. Our results showed that low nickel concentrations in the catalyst led to high metallic dispersion; however, very low nickel concentrations did not favor the methane transformation into Syngas. The catalyst containing only NiO/ZrO2 in the mixture was not sufficient for the catalysis. The presence of the promoter PrO2 was very important for the catalysis of the POM.

  8. Effects of preparation method on the performance of Ni/Al(2)O(3) catalysts for hydrogen production by bio-oil steam reforming.

    Science.gov (United States)

    Li, Xinbao; Wang, Shurong; Cai, Qinjie; Zhu, Lingjun; Yin, Qianqian; Luo, Zhongyang

    2012-09-01

    Steam reforming of bio-oil derived from the fast pyrolysis of biomass is an economic and renewable process for hydrogen production. The main objective of the present work has been to investigate the effects of the preparation method of Ni/Al(2)O(3) catalysts on their performance in hydrogen production by bio-oil steam reforming. The Ni/Al(2)O(3) catalysts were prepared by impregnation, co-precipitation, and sol-gel methods. XRD, XPS, H(2)-TPR, SEM, TEM, TG, and N(2) physisorption measurements were performed to characterize the texture and structure of the catalysts obtained after calcination and after their subsequent use. Ethanol and bio-oil model compound were selected for steam reforming to evaluate the catalyst performance. The catalyst prepared by the co-precipitation method was found to display better performance than the other two. Under the optimized reaction conditions, an ethanol conversion of 99% and a H(2) yield of 88% were obtained.

  9. Confined-space alloying of nanoparticles for the synthesis of efficient PtNi fuel-cell catalysts.

    Science.gov (United States)

    Baldizzone, Claudio; Mezzavilla, Stefano; Carvalho, Hudson W P; Meier, Josef Christian; Schuppert, Anna K; Heggen, Marc; Galeano, Carolina; Grunwaldt, Jan-Dierk; Schüth, Ferdi; Mayrhofer, Karl J J

    2014-12-15

    The efficiency of polymer electrolyte membrane fuel cells is strongly depending on the electrocatalyst performance, that is, its activity and stability. We have designed a catalyst material that combines both, the high activity for the decisive cathodic oxygen reduction reaction associated with nanoscale Pt alloys, and the excellent durability of an advanced nanostructured support. Owing to the high specific activity and large active surface area, the catalyst shows extraordinary mass activity values of 1.0 A mgPt(-1). Moreover, the material retains its initial active surface area and intrinsic activity during an extended accelerated aging test within the typical operation range. This excellent performance is achieved by confined-space alloying of the nanoparticles in a controlled manner in the pores of the support.

  10. Steam reforming of tar derived from lignin over pompom-like potassium-promoted iron-based catalysts formed on calcined scallop shell.

    Science.gov (United States)

    Guan, Guoqing; Kaewpanha, Malinee; Hao, Xiaogang; Zhu, Ai-Min; Kasai, Yutaka; Kakuta, Seiji; Kusakabe, Katsuki; Abudula, Abuliti

    2013-07-01

    In order to understand the improvement effect of potassium (K) on the catalytic activity of iron-loaded calcined scallop shell (CS) for the steam reforming tar derived from biomass, various K precursors were applied for the catalyst preparation. It is found that pompom-like iron-based particles with a mesoporous structure were easily formed on the surface of calcined scallop shell (CS) when K2CO3 was used as K precursor while no such kind of microsphere was formed when other kinds of K precursors such as KOH and KNO3 were applied. The optimum K-loading amount for the preparation of this catalyst was investigated. Based on the experimental results obtained, a mechanism for the formation of these microspheres was proposed. This pompom-like potassium-promoted iron-based catalyst showed a better catalytic activity and reusability for the steam reforming of tar derived from lignin.

  11. 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

  12. Physico-chemical characterisations and catalytic performance of Ni-based catalyst systems for dry reforming of methane

    Energy Technology Data Exchange (ETDEWEB)

    Vlach, K.; Hoang, D.L.; Schneider, M.; Pohl, M.M.; Armbruster, U.; Martin, A. [Rostock Univ. (Germany). Leibniz-Institut fuer Katalyse e.V.

    2012-07-01

    In this study, ternary perovskite type oxides LaNi{sub x}Cu{sub 1-x}O{sub 3} (x = 0, 0.2, 0.5, 0.8, 1) were synthesized using NaOH and diethylenetriaminepentaacetic acid (H{sub 5}DTPA). The catalysts resulting from perovskite precursors exhibit catalytic activities for CO{sub 2} reforming of CH{sub 4} at 700 C that increase with a higher Ni content. Characterization methods showed that the activation led to formation of small metallic Ni/Cu particles. Methane and carbon dioxide conversions varied from 20 to 65% for CH{sub 4} and 3 to 58% for CO{sub 2}. Selectivities from 46 to 93% for CO and from 4 to 64% for H{sub 2} were obtained. (orig.)

  13. Effectiveness factors for a commercial steam reforming (Ni) catalyst and for a calcined dolomite used downstream biomass gasifiers

    Energy Technology Data Exchange (ETDEWEB)

    Corella, J.; Narvaez, I.; Orio, A. [Madrid Univ. (Spain). Dept. of Chem. Eng.

    1996-12-31

    A commercial steam reforming catalyst from BASF, the G1-25 S one, and a calcined dolomite, Norte-1, from Cantabria-Spain, have been used, once crushed and sieved to different particle fractions between 1.0 and 4.0 mm. The materials have been tested downstream small pilot biomass gasifiers, bubbling fluidized bed type, gasifying with air and with steam. The Thiele modulus and the effectiveness factor have been calculated at temperatures of 750-850 deg C. It is experimentally shown that diffusion control plays an important part when particle size is larger than ca. 0.5 mm. This has to be taken into account when comparing the quality of the solids for tar elimination. (author) (5 refs.)

  14. Improving Heterogeneous Catalyst Stability for Liquid-phase Biomass Conversion and Reforming.

    Science.gov (United States)

    Héroguel, Florent; Rozmysłowicz, Bartosz; Luterbacher, Jeremy S

    2015-01-01

    Biomass is a possible renewable alternative to fossil carbon sources. Today, many bio-resources can be converted to direct substitutes or suitable alternatives to fossil-based fuels and chemicals. However, catalyst deactivation under the harsh, often liquid-phase reaction conditions required for biomass treatment is a major obstacle to developing processes that can compete with the petrochemical industry. This review presents recently developed strategies to limit reversible and irreversible catalyst deactivation such as metal sintering and leaching, metal poisoning and support collapse. Methods aiming to increase catalyst lifetime include passivation of low-stability atoms by overcoating, creation of microenvironments hostile to poisons, improvement of metal stability, or reduction of deactivation by process engineering.

  15. A microstructural investigation of gas atomized Raney type Al-27.5 at.% Ni catalyst precursor alloys

    Energy Technology Data Exchange (ETDEWEB)

    Mullis, A.M., E-mail: a.m.mullis@leeds.ac.uk [Institute for Materials Research, University of Leeds, Leeds LS2 9JT (United Kingdom); Bigg, T.D., E-mail: t.bigg@leeds.ac.uk [Institute for Materials Research, University of Leeds, Leeds LS2 9JT (United Kingdom); Adkins, N.J., E-mail: n.j.e.adkins@bham.ac.uk [IRC in Materials Processing, University of Birmingham, Edgbaston, Birmingham B15-2TT (United Kingdom)

    2015-11-05

    Quantitative image analysis has been used to investigate the phase composition of gas atomized powders of a Raney type Ni catalyst precursor alloys of composition Al-27.5 at.% Ni in the powder size range 150–212 μm. We find that there are considerable variations in phase composition both between powders from the same batch and as a function distance from the particle surface within individual particles. Such variations may have significant implications for the future production and uptake of such catalysts, including the necessity for post-production crushing of gas atomized powders. Models are proposed to account for both variations. - Highlights: • The phase composition of powder Raney-Ni catalysts has been investigated. • Image analysis is used to quantify differences between and within particles. • Phase composition can vary by up to 10% between the particle surface and centre. • Differences of up to 10% in the mean composition are also found between particles.

  16. Suppression of carbon formation in CH4–CO2 reforming by addition of Sr into bimetallic Ni–Co/γ-Al2O3 catalyst

    Directory of Open Access Journals (Sweden)

    Ahmed Al-Fatesh

    2015-01-01

    Full Text Available Bimetallic catalysts, containing 5 wt% Ni + 5 wt% Co supported on γ-Al2O3 combined with different amounts of Sr promoter ranging from 0 to 1 wt%, for dry reforming reaction were prepared by the impregnation method. The dry reforming reaction was carried out at atmospheric pressure using CO2/CH4/N2 feed ratio of 17/17/2, F/W = 60 mL/min gcat and reaction temperature range of 500–700 °C. The performance of the developed catalyst was evaluated by estimating the CH4 and CO2 conversions, and by performing a long run stability test. The fresh and spent catalysts were characterized by BET, TGA, TPD, TPR, and TPO. The bimetallic catalysts provided higher activity than the monometallic-catalysts. When the bimetallic was promoted with Sr, the activity decreased slightly however, the stability enhanced. The best stability, estimated by the deactivation factor, and less carbon deposition, measured by TGA, were obtained when 5Ni5CoSr0.75 catalyst was used.

  17. Effect of Ni Loading and CexZr1-xO2 Promoter on Ni-Based SBA-15 Catalysts for Steam Reforming of Methane

    Institute of Scientific and Technical Information of China (English)

    Huijun Wan; Xiujin Li; Shengfu Ji; Bingyao Huang; Kai Wang; Chengyue Li

    2007-01-01

    A series of Ni/SBA-15 catalysts with Ni contents ranging from 5wt% to 20wt% as well as 10wt%Ni/10wt%CexZr1-xO2/SBA-15 (x=0, 0.5, 1) were prepared. The structures of the catalysts were characterized using XRD, TPR, TEM and BET techniques. The catalytic activities of the catalysts for steam reforming of methane were evaluated in a continuous flow microreactor. The results indicated that both the Ni/SBA-15 and the Ni/CexZr1-xO2/SBA-15 catalysts had good catalytic activities at atmospheric pressure. The 10wt%Ni/SBA-15 catalyst exhibited excellent stability at 800 ℃ for time on stream of 740 h. After the reaction, carbon deposits were not formed on the surface of the catalyst. There existed a regular hexagonal mesoporous structure in the Ni/SBA-15 and the Ni/CexZr1-xO2/SBA-15 catalysts. The nickel species and the CexZr1-xO2 component were all confined in the SBA-15 mesopores.The CexZr1-xO2 could promote dispersion of the nickel species in the Ni/CexZr1-xO2/SBA-15 catalysts.

  18. Hydrogen production by steam reforming of bio-oil aqueous fraction over Ni/CeO{sub 2}-ZrO{sub 2} catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Chang-Feng; Cheng, Fei-Fei; Hu, Rong-Rong [Chinese Academy of Sciences, Guangzhou (China). Guangzhou Inst. of Energy Conversion

    2010-07-01

    Two kinds of Ni/CeO{sub 2}-ZrO{sub 2} catalysts were prepared by impregnation method or by coprecipitation method. A laboratory scale fixed-bed reactor was employed to investigate the catalyst performance in hydrogen production by steam reforming bio-oil aqueous fraction. Effects of reaction temperature, and the different preparation methods of the catalyst on the hydrogen production performance of Ni/CeO{sub 2}-ZrO{sub 2} catalysts were examined. The obtained results were compared with commercial nickel-based catalysts (Z417). Ni/CeO{sub 2}-ZrO{sub 2} catalyst by co-precipitation method showed the best catalytic performances. At W/B=4.9, T=800 C, H{sub 2} yield reaches the highest of 72.9 % and H{sub 2} content of 70.0 % were obtained., these values were higher than Ni/CeO{sub 2}-ZrO{sub 2} catalysts were prepared by impregnation method and commercial nickel-based catalysts (Z417). (orig.)

  19. Platinum–nickel nanowire catalysts with composition-tunable alloying and faceting for the oxygen reduction reaction

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Fangfang; Yu, Gang; Shan, Shiyao; Skeete, Zakiya; Wu, Jinfang; Luo, Jin; Ren, Yang; Petkov, Valeri; Zhong, Chuan-Jian

    2017-01-01

    The ability to tune the alloying properties and faceting characteristics of bimetallic nanocatalysts is essential for designing catalysts with enhanced activity and stability through optimizing strain and ligand effects, which is an important frontier for designing advanced materials as catalysts for fuel cell applications. This report describes composition-controlled alloying and faceting of platinum–nickel nanowires (PtNi NWs) for the electrocatalytic oxygen reduction reaction. The PtNi NWs are synthesized by a surfactant-free method and are shown to display bundled morphologies of nano-tetrahedra or nanowires, featuring an ultrathin and irregular helix morphology with composition-tunable facets. Using high-energy synchrotron X-ray diffraction coupled with atomic pair distribution function analysis, lattice expansion and shrinking are revealed, with the Pt : Ni ratio of ~3 : 2 exhibiting a clear expansion, which coincides with the maximum electrocatalytic activity for the ORR. In comparison with PtNi nanoparticles (NPs), the PtNi NWs display remarkably higher electrocatalytic activity and stability as a result of the composition dependent atomic-scale alloying and faceting, demonstrating a new pathway to the design of alloy nanocatalysts with enhanced activity and durability for fuel cells.

  20. A Match on Dry Grass: Community Organizing as a Catalyst for School Reform

    Science.gov (United States)

    Warren, Mark R.; Mapp, Karen L.

    2011-01-01

    The persistent failure of public schooling in low-income communities constitutes one of our nation's most pressing civil rights and social justice issues. Many school reformers recognize that poverty, racism, and a lack of power held by these communities undermine children's education and development, but few know what to do about it. "A…

  1. Renewable hydrogen: carbon formation on Ni and Ru catalysts during ethanol steam-reforming

    DEFF Research Database (Denmark)

    Rass-Hansen, Jeppe; Christensen, Christina Hviid; Sehested, J.;

    2007-01-01

    Biomass is probably the only realistic green and sustainable carbonaceous alternative to fossil fuels. By degradation and fermentation, it can be converted into bioethanol, which is a chemical with a range of possible applications. In this study, the catalytic steam-reforming of ethanol for the p...

  2. Mechanical alloying of a hydrogenation catalyst used for the remediation of contaminated compounds

    Science.gov (United States)

    Quinn, Jacqueline W. (Inventor); Clausen, Christian A. (Inventor); Geiger, Cherie L. (Inventor); Aitken, Brian S. (Inventor)

    2012-01-01

    A hydrogenation catalyst including a base material coated with a catalytic metal is made using mechanical milling techniques. The hydrogenation catalysts are used as an excellent catalyst for the dehalogenation of contaminated compounds and the remediation of other industrial compounds. Preferably, the hydrogenation catalyst is a bimetallic particle including zero-valent metal particles coated with a catalytic material. The mechanical milling technique is simpler and cheaper than previously used methods for producing hydrogenation catalysts.

  3. Effects of Catalysts and Membranes on the Performance of Membrane Reactors in Steam Reforming of Ethanol at Moderate Temperature

    Directory of Open Access Journals (Sweden)

    Manabu Miyamoto

    2016-06-01

    Full Text Available Steam reforming of ethanol in the membrane reactor using the Pd77Ag23 membrane was evaluated in Ni/CeO2 and Co/CeO2 at atmospheric pressure. At 673 K, the H2 yield in the Pd77Ag23 membrane reactor over Co/CeO2 was found to be higher than that over Ni/CeO2, although the H2 yield over Ni/CeO2 exceeded that over Co/CeO2 at 773 K. This difference was owing to their reaction mechanism. At 773 K, the effect of H2 removal could be understood as the equilibrium shift. In contrast, the H2 removal kinetically inhibited the reverse methane steam reforming at low temperature. Thus, the low methane-forming reaction rate of Co/CeO2 was favorable at 673 K. The addition of a trace amount of Ru increased the H2 yield effectively in the membrane reactor, indicating that a reverse H2 spill over mechanism of Ru would enhance the kinetical effect of H2 separation. Finally, the effect of membrane performance on the reactor performance by using amorphous alloy membranes with different compositions was evaluated. The H2 yield was set in the order of H2 permeation flux regardless of the membrane composition.

  4. 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

  5. CO-free hydrogen from steam-reforming of bioethanol over ZnO-supported cobalt catalysts. Effect of the metallic precursor

    Energy Technology Data Exchange (ETDEWEB)

    Llorca, Jordi; De la Piscina, Pilar Ramirez; Sales, Joaquim; Homs, Narcis [Departament de Quimica Inorganica, Universitat de Barcelona, c/Marti i Franques 1-11, 08028 Barcelona (Spain); Dalmon, Jean-Alain [Institut de Recherches sur la Catalyse-CNRS, 2 Avenue Albert Einstein, 69626 Villeurbanne (France)

    2003-07-25

    The ethanol steam-reforming reaction was studied over ZnO-supported cobalt catalysts (10wt.% Co). Catalysts were prepared by impregnation of nitrate and carbonyl cobalt precursors. Characterization was accomplished by transmission electron microscopy (TEM), Raman spectroscopy, UV-Vis diffuse reflectance spectroscopy (DRS), X-ray diffraction (XRD), and in situ techniques: magnetic measurements, and diffuse reflectance infrared spectroscopy (DRIFT) coupled to mass spectrometry. The use of Co{sub 2}(CO){sub 8} as precursor produced a catalyst that was highly stable and selective for the production of CO-free hydrogen at reaction temperature as low as 623K. The only by-product was methane and selectivity of 73% to H{sub 2} and 25% to CO{sub 2} was obtained. Under reaction conditions, the catalyst showed 92% of reduced cobalt, mainly as small particles.

  6. Production of Renewable Hydrogen from Glycerol Steam Reforming over Bimetallic Ni-(Cu,Co,Cr Catalysts Supported on SBA-15 Silica

    Directory of Open Access Journals (Sweden)

    Alicia Carrero

    2017-02-01

    Full Text Available Glycerol steam reforming (GSR is a promising alternative to obtain renewable hydrogen and help the economics of the biodiesel industry. Nickel-based catalysts are typically used in reforming reactions. However, the choice of the catalyst greatly influences the process, so the development of bimetallic catalysts is a research topic of relevant interest. In this work, the effect of adding Cu, Co, and Cr to the formulation of Ni/SBA-15 catalysts for hydrogen production by GSR has been studied, looking for an enhancement of its catalytic performance. Bimetallic Ni-M/SBA-15 (M: Co, Cu, Cr samples were prepared by incipient wetness co-impregnation to reach 15 wt % of Ni and 4 wt % of the second metal. Catalysts were characterized by inductively coupled plasma atomic emission spectroscopy (ICP-AES, N2-physisorption, X-ray powder diffraction (XRD, hydrogen temperature programmed reduction (H2-TPR, transmission electron microscopy (TEM, scanning electron microscopy (SEM, and thermogravimetric analyses (TGA, and tested in GSR at 600 °C and atmospheric pressure. The addition of Cu, Co, and Cr to the Ni/SBA-15 catalyst helped to form smaller crystallites of the Ni phase, this effect being more pronounced in the case of the Ni-Cr/SBA-15 sample. This catalyst also showed a reduction profile shifted towards higher temperatures, indicating stronger metal-support interaction. As a consequence, the Ni-Cr/SBA-15 catalyst exhibited the best performance in GSR in terms of glycerol conversion and hydrogen production. Additionally, Ni-Cr/SBA-15 achieved a drastic reduction in coke formation compared to the Ni/SBA-15 material.

  7. Mechanism of carbon deposit/removal in methane dry reforming on supported metal catalysts

    NARCIS (Netherlands)

    Nagaoka, K.; Seshan, K.; Lercher, J.A.; Aika, A.; Iglesia, E.; Spivey, J.J.; Fleisc, T.H.

    2001-01-01

    The greater resistance to coke deposition for Pt/ZrO2 compared to Pt/Al2O3 in the CH4/CO2 reaction has been attributed to the higher reactivity of coke with CO2 on Pt/ZrO2 [1]. Hence, in this communication, the reaction of coke derived from methane (CHx: which is an intermediated in the reforming re

  8. Mechanism of carbon deposit - removal in methane dry reforming on supported metal catalysts

    NARCIS (Netherlands)

    Nagaoka, K.; Nagaoka, K.; Seshan, Kulathuiyer; Lercher, J.A.; Aika, A.; Iglesia, E.; Spivey, J.J.; Fleisc, T.H.

    2001-01-01

    The greater resistance to coke deposition for Pt/ZrO2 compared to Pt/Al2O3 in the CH4/CO2 reaction has been attributed to the higher reactivity of coke with CO2 on Pt/ZrO2 [1]. Hence, in this communication, the reaction of coke derived from methane (CHx: which is an intermediated in the reforming re

  9. Dry (CO{sub 2}) reforming of methane over Pt catalysts studied by DFT and kinetic modeling

    Energy Technology Data Exchange (ETDEWEB)

    Niu, Juntian [Key Laboratory of Low-grade Energy Utilization Technologies and Systems, Ministry of Education of PRC, Chongqing University, Chongqing, 400044 (China); College of Power Engineering, Chongqing University, Chongqing, 400044 (China); Du, Xuesen, E-mail: xuesendu@cqu.edu.cn [Key Laboratory of Low-grade Energy Utilization Technologies and Systems, Ministry of Education of PRC, Chongqing University, Chongqing, 400044 (China); College of Power Engineering, Chongqing University, Chongqing, 400044 (China); Ran, Jingyu, E-mail: jyran@189.cn [Key Laboratory of Low-grade Energy Utilization Technologies and Systems, Ministry of Education of PRC, Chongqing University, Chongqing, 400044 (China); College of Power Engineering, Chongqing University, Chongqing, 400044 (China); Wang, Ruirui [Key Laboratory of Low-grade Energy Utilization Technologies and Systems, Ministry of Education of PRC, Chongqing University, Chongqing, 400044 (China); College of Power Engineering, Chongqing University, Chongqing, 400044 (China)

    2016-07-15

    Graphical abstract: - Highlights: • CH appears to be the most abundant species on Pt(1 1 1) surface in CH{sub 4} dissociation. • CO{sub 2}* + H* → COOH* + * → CO* + OH* is the dominant reaction pathway in CO{sub 2} activation. • Major reaction pathway in CH oxidation: CH* + OH* → CHOH* + * → CHO* + H* → CO* + 2H*. • C* + OH* → COH* + * → CO* + H* is the dominant reaction pathway in C oxidation. - Abstract: Dry reforming of methane (DRM) is a well-studied reaction that is of both scientific and industrial importance. In order to design catalysts that minimize the deactivation and improve the selectivity and activity for a high H{sub 2}/CO yield, it is necessary to understand the elementary reaction steps involved in activation and conversion of CO{sub 2} and CH{sub 4}. In our present work, a microkinetic model based on density functional theory (DFT) calculations is applied to explore the reaction mechanism for methane dry reforming on Pt catalysts. The adsorption energies of the reactants, intermediates and products, and the activation barriers for the elementary reactions involved in the DRM process are calculated over the Pt(1 1 1) surface. In the process of CH{sub 4} direct dissociation, the kinetic results show that CH dissociative adsorption on Pt(1 1 1) surface is the rate-determining step. CH appears to be the most abundant species on the Pt(1 1 1) surface, suggesting that carbon deposition is not easy to form in CH{sub 4} dehydrogenation on Pt(1 1 1) surface. In the process of CO{sub 2} activation, three possible reaction pathways are considered to contribute to the CO{sub 2} decomposition: (I) CO{sub 2}* + * → CO* + O*; (II) CO{sub 2}* + H* → COOH* + * → CO* + OH*; (III) CO{sub 2}* + H* → mono-HCOO* + * → bi-HCOO* + * [CO{sub 2}* + H* → bi-HCOO* + *] → CHO* + O*. Path I requires process to overcome the activation barrier of 1.809 eV and the forward reaction is calculated to be strongly endothermic by 1.430 eV. In

  10. Low Temperature and H2 Selective Catalysts for Ethanol Steam Reforming

    Energy Technology Data Exchange (ETDEWEB)

    Roh, Hyun-Seog; Wang, Yong; King, David L.; Platon, Alex; Chin, Ya-Huei

    2006-04-01

    Supported Rh catalysts have been developed for selective H2 production at low temperatures. Ethanol dehydration is favorable over either acidic or basic supports such as γ-Al2O3 and MgAl2O4, while ethanol dehydrogenation is more favorable over neutral supports. A series of CeO2-ZrO2 supports with various CeO2/ZrO2 ratios were prepared by a co-precipitation method and Rh was impregnated on the as-synthesized support to achieve a strong metal to support interaction (SMSI). 2%Rh/Ce0.8Zr0.2O2 catalyst exhibited the highest H2 yield at 450oC among the various supported Rh catalysts evaluated in this study. This is mainly due to a favored reaction pathway via ethanol dehydrogenation to form the acetaldehyde intermediate, and both the strong interaction between Rh and Ce0.8Zr0.2O2 and the high oxygen storage capacity of Ce0.8Zr0.2O2 which favors oxidation of acetaldehyde decomposition products

  11. Enhancement of Glycerol Steam Reforming Activity and Thermal Stability by Incorporating CeO2 and TiO2 in Ni- and Co-MCM-41 Catalysts

    Science.gov (United States)

    Dade, William N.

    Hydrogen (H2) has many applications in industry with current focus shifted to production of hydrocarbon fuels and valuable oxygenates using the Fischer-Tropsch technology and direct use in proton exchange membrane fuel cell (PEMFC). Hydrogen is generally produced via steam reforming of natural gas or alcohols like methanol and ethanol. Glycerol, a by-product of biodiesel production process, is currently considered to be one of the most attractive sources of sustainable H2 due to its high H/C ratio and bio-based origin. Ni and Co based catalysts have been reported to be active in glycerol steam reforming (GSR); however, deactivation of the catalysts by carbon deposition and sintering under GSR operating conditions is a major challenge. In this study, a series of catalysts containing Ni and Co nanoparticles incorporated in CeO2 and TiO2 modified high surface area MCM-41 have been synthesized using one-pot method. The catalysts are tested for GSR (at H2O/Glycerol mole ratio of 12 and GHSV of 2200 h-1) to study the effect of support modification and reaction temperature (450 - 700 °C) on the product selectivity and long term stability. GSR results revealed that all the catalysts performed significantly well exhibiting over 85% glycerol conversion at 650 °C except Ni catalysts that showed better low temperature activities. Deactivation studies of the catalysts conducted at 650 °C indicated that the Ni-TiO2-MCM-41 and Ni-CeO 2-MCM-41 were resistant to deactivation with ˜100% glycerol conversion for 40 h. In contrast, Co-TiO2-MCM-41 perform poorly as the catalyst rapidly deactivated after 12 h to yield ˜20% glycerol conversion after 40 h. The WAXRD and TGA-DSC analyses of spent catalysts showed a significant amount of coke deposition that might explain catalysts deactivation. The flattening shape of the original BET type IV isotherm with drastic reduction of catalyst surface area can also be responsible for observed drop in catalysts activities.

  12. CH4 reforming with CO2 for syngas production over La2O3 promoted Ni catalysts supported on mesoporous nanostructuredγ-Al2O3

    Institute of Scientific and Technical Information of China (English)

    Narges Habibi; Mehran Rezaei; Nasrollah Majidian; Mahmood Andache

    2014-01-01

    Nanostructuredγ-Al2O3 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, N2 adsorption-desorption, TPR, TPO, TPH, NH3-TPD and SEM techniques. The BET analysis showed a high surface area of 204 m2·g-1 and a narrow pore-size distribution centered at a diameter of 5.5 nm for catalyst support. The BET results revealed that addition of lanthanum oxide to aluminum oxide decreased the specific surface area. In addition, TPR results showed that addition of lanthanum oxide increased the reducibility of nickel catalyst. The catalytic evaluation results showed an increase in methane conversion with increasing lanthanum oxide to 3 mol%and further increase in lanthanum content decreased the catalytic activity. TPO analysis revealed that the coke deposition decreased with increasing lanthanum oxide to 3 mol%. SEM and TPH analyses confirmed the formation of whisker type carbon over the spent catalysts. Addition of steam and O2 to dry reforming feed increased the methane conversion and led to carbon free operation in combined processes.

  13. High yield hydrogen production from low CO selectivity ethanol steam reforming over modified Ni/Y 2O 3 catalysts at low temperature for fuel cell application

    Science.gov (United States)

    Sun, Jie; Luo, Dingfa; Xiao, Pu; Jigang, Li; Yu, Shanshan

    Ethanol-water mixtures were converted directly into H 2 with 67.6% yield and >98% conversion by catalytic steam reforming at 350 °C over modified Ni/Y 2O 3 catalysts heat treated at 500 °C. XRD was used to test the structure and calculate the grain sizes of the samples with different scan rates. The initial reaction kinetics of ethanol over modified and unmodified Ni/Y 2O 3 catalysts were studied by steady state reaction and a first-order reaction with respect to ethanol was found. TPD was used to analyze mechanism of ethanol desorption over Ni/Y 2O 3 catalyst. Rapid vaporization, efficiency tube reactor and catalyst were used so that homogeneous reactions producing carbon, acetaldehyde, and carbon monoxide could be minimized. And even no CO detective measured during the first 49 h reforming test on the modified catalyst Ni/Y 2O 3. This process has great potential for low cost H 2 generation in fuel cells for small portable applications where liquid fuel storage is essential and where systems must be small, simple, and robust.

  14. Oxidative-reforming of model biogas over NiO/Al2O3 catalysts: The influence of the variation of support synthesis conditions

    Science.gov (United States)

    Asencios, Yvan J. O.; Elias, Kariny F. M.; Assaf, Elisabete M.

    2014-10-01

    In this study, nickel catalysts (20 wt%) supported on γ-Al2O3 were prepared by the impregnation method. The γ-Al2O3, 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 (H2-TPR), X-ray diffraction (XRD), physisorption of N2 (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, NiAl2O4 and γ-Al2O3. The best catalysts (samples NiAl7-25 and NiAl7-80) synthesized in this report showed high stability and high conversion values (CH4 (70%) and CO2 (78%)). These catalysts showed better performance than the catalyst supported on commercial γ-Al2O3, which showed a high coke formation which affected the course of the reaction. The γ-Al2O3 synthesized from bayerite obtained at neutral pH conditions was the best support for nickel catalysts in the oxidative-reforming of model biogas.

  15. Factors affecting the long-term stability of mesoporous nickel-based catalysts in combined steam and dry reforming of methane

    OpenAIRE

    Jabbour, K.; El Hassan, N.; Davidson, A.; Casale, S.; Massiani, Pascale

    2016-01-01

    International audience; An ordered mesoporous " one-pot " nickel-alumina catalyst (5 wt% Ni) was synthesized using the evaporation-induced self-assembly method. Compared to an impregnated and to a non-porous catalysts, the ordered "one-pot" Ni-alumina sample displayed, after in-situ reduction, the highest and the most stable catalytic performances along 40h of run at 800°C in combined steam and dry reforming of methane, with conversion and selectivity values close to the thermodynamic expecte...

  16. Modification the Oxalic Co-precipitation Method on a Novel Catalyst Cu/Zn/Al2O3/Cr2O3 for Autothermal Reforming Reaction of Methanol

    OpenAIRE

    Cheng- Hsin Kuo; Donny Lesmana; Ho Shing Wu

    2013-01-01

    This study addresses the catalytic performance of Cu/ZnO/Al2O3/Cr2O3 in low-temperature of autothermal reforming (ATR) reaction. Various operating conditions were used to decide the optimum reaction conditions: type of promoter (ZrO2, CeO2, and Cr2O3), precipitation temperature, precipitation pH, operation temperature, molar ratio of O2/CH3OH (O/C), and weight hourly space velocity (WHSV). The catalysts were prepared using the oxalic coprecipitation method. Characterization of the catalyst wa...

  17. Methods to synthesize NiPt bimetallic nanoparticles by a reversed-phase microemulsion, deposition of NiPt bimetallic nanoparticles on a support, and application of the supported catalyst for CO.sub.2 reforming of methane

    KAUST Repository

    Biausque, Gregory

    2015-04-28

    Methods to synthesize NiPt bimetallic nanoparticles by a reversed-phase microemulsion, deposition of NiPt bimetallic nanoparticles on a support, and application of the supported catalyst for CO.sub.2 reforming of methane

  18. The electro-oxidation of H{sub 2} and H{sub 2}/CO mixtures on carbon-supported Pt{sub x}Mo{sub y} alloy catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Grgur, B.N.; Markovic, N.M.; Ross, P.N. [Lawrence Berkeley National Lab., CA (United States)]|[Univ. of California, Berkeley, CA (United States). Materials Sciences Div.

    1999-05-01

    Electro-oxidation kinetics of H{sub 2} and H{sub 2}/CO mixture were studied on bimetallic Pt-Mo catalysts supported on a high-surface-area carbon black. The Pt:Mo atomic ratios in the catalysts were 3:1 and 4:1. Characterization of these catalysts by X-ray diffraction indicated the existence of a face-centered cubic metallic phase with an average particle size of ca. 4 nm. Because the lattice constants for the Pt-Mo solid solutions are so close to those of pure Pt, the composition of the nanocrystalline phase could not be determined. The kinetic results with the supported catalysts were compared quantitatively with results from bulk alloy electrodes having well-characterized surface compositions varying from 15 to 33 atom % Mo. The kinetic properties of the supported catalysts were comparable to those of bulk alloys having somewhat higher Mo concentrations than the atomic ratios in the catalysts. This suggests that either the surface segregation phenomena in the alloy nanocrystals are different from those in the bulk or that the alloying by Pt is incomplete, and the alloy nanocrystals are rich in Mo relative to the atomic ratios in the catalysts. The authors prefer the latter interpretation. These Pt-Mo alloy catalysts are predicted to have significantly better CO tolerance in polymer electrolyte membrane fuel cells than Pt-Ru alloy catalysts, consistent with previous predictions based on studies of bulk alloy electrodes.

  19. Nanoporous PdNi Alloy Nanowires As Highly Active Catalysts for the Electro-Oxidation of Formic Acid.

    Science.gov (United States)

    Du, Chunyu; Chen, Meng; Wang, Wengang; Yin, Geping

    2011-02-01

    Highly active and durable catalysts for formic acid oxidation are crucial to the development of direct formic acid fuel cell. In this letter, we report the synthesis, characterization, and electrochemical testing of nanoporous Pd(57)Ni(43) alloy nanowires for use as the electrocatalyst towards formic acid oxidation (FAO). These nanowires are prepared by chemically dealloying of Ni from Ni-rich PdNi alloy nanowires, and have high surface area. X-ray diffraction data show that the Pd(57)Ni(43) nanowires have the face-centered cubic crystalline structure of pure Pd, whereas X-ray photoelectron spectroscopy confirm the modification of electronic structure of Pd by electron transfer from Ni to Pd. Electrocatalytic activity of the nanowires towards FAO exceeds that of the state-of-the-art Pd/C. More importantly, the nanowires are highly resistant to deactivation. It is proposed that the high active surface area and modulated surface properties by Ni are responsible for the improvement of activity and durability. Dealloyed nanoporous Pd(57)Ni(43) alloy nanowires are thus proposed as a promising catalyst towards FAO.

  20. A micro-structured 5kW complete fuel processor for iso-octane as hydrogen supply system for mobile auxiliary power units Part I. Development of autothermal reforming catalyst and reactor

    OpenAIRE

    Kolb, Gunther; Baier, Tobias; Schürer, Jochen; Tiemann, David; Ziogas, Athanassios; Ehwald, Hermann; Alphonse, Pierre

    2008-01-01

    A micro-structured autothermal reformer was developed for a fuel processing/fuel cell system running on iso-octane and designed for an electrical power output of 5kWel. The target application was an automotive auxiliary power unit (APU). The work covered both catalyst and reactor development. In fixed bed screening, nickel and rhodium were identified as the best candidates for autothermal reforming of gasoline. Under higher feed flow rates applied in microchannel testing, a catalyst formul...

  1. Modification the Oxalic Co-precipitation Method on a Novel Catalyst Cu/Zn/Al2O3/Cr2O3 for Autothermal Reforming Reaction of Methanol

    Directory of Open Access Journals (Sweden)

    Cheng- Hsin Kuo

    2013-12-01

    Full Text Available This study addresses the catalytic performance of Cu/ZnO/Al2O3/Cr2O3 in low-temperature of autothermal reforming (ATR reaction. Various operating conditions were used to decide the optimum reaction conditions: type of promoter (ZrO2, CeO2, and Cr2O3, precipitation temperature, precipitation pH, operation temperature, molar ratio of O2/CH3OH (O/C, and weight hourly space velocity (WHSV. The catalysts were prepared using the oxalic coprecipitation method. Characterization of the catalyst was conducted using a porosity analyzer, XRD, and SEM. The methanol conversion and volumetric percentage of hydrogen using the best catalyst (Cu/ZnO/Al2O3/Cr2O3 exceeded 93% and 43%, respectively. A catalyst prepared by precipitation at -5 oC and at pH of 1 converted methanol to 40% H2 and less than 3000 ppm CO at reaction temperature of 200 oC. The size and dispersion of copper and the degradation rate and turnover frequency of the catalyst was also calculated. Deactivation of the Cu catalyst at a reaction temperature of 200 oC occurred after 30 h. © 2013 BCREC UNDIP. All rights reservedReceived: 8th May 2013; Revised: 10th August 2013; Accepted: 18th August 2013[How to Cite: Cheng, H.K., Lesmana, D., Wu, H.S. (2013. Modification the Oxalic Co-precipitation Method on a Novel Catalyst Cu/Zn/Al2O3/Cr2O3 for Autothermal Reforming Reaction of Methanol. Bulletin of Chemical Reaction Engineering & Catalysis, 8 (2: 110-124. (doi:10.9767/bcrec.8.2.4844.110-124][Permalink/DOI: http://dx.doi.org/10.9767/bcrec.8.2.4844.110-124

  2. Development of robust Co-based catalysts for the selective H{sub 2}-production by ethanol steam-reforming. The Fe-promoter effect

    Energy Technology Data Exchange (ETDEWEB)

    De la Pena O' Shea, Victor A.; Nafria, Raquel; Ramirez de la Piscina, Pilar; Homs, Narcis [Departament de Quimica Inorganica, Institut de Nanociencia i Nanotecnologia, Universitat de Barcelona, Marti i Franques 1-11, 08028 Barcelona (Spain)

    2008-07-15

    The effect of iron promoter on cobalt-based catalysts, active in the ethanol steam-reforming, was studied. Fe{sub x}Co{sub 3-x}O{sub 4}(0{<=} x{<=}0.60) oxides prepared by co-precipitation and an Fe-doped Co{sub 3}O{sub 4} prepared by wetness impregnation are analysed. The activation process of the oxides under reaction conditions was studied by in situ X-ray diffraction (XRD); the activation depended on the iron content of the oxides. The systems were characterized by means of temperature programmed reduction (TPR), XRD and tested in the ethanol steam-reforming reaction at 623-673 K. An optimal iron loading that gives rise to a high H{sub 2}selectivity and catalyst stability was determined. (author)

  3. Coke- and sintering-resistant monolithic catalysts derived from in situ supported hydrotalcite-like films on Al wires for dry reforming of methane

    Science.gov (United States)

    Du, Xianjun; Zhang, Dengsong; Shi, Liyi; Gao, Ruihua; Zhang, Jianping

    2013-03-01

    Monolithic catalysts derived from in situ supported hydrotalcite-like films on Al wires display high resistance to coke formation and sintering in the dry reforming of methane due to their hierarchical porous structure, well dispersed metallic nickel species, more basic sites and strong metal-support interaction effect.Monolithic catalysts derived from in situ supported hydrotalcite-like films on Al wires display high resistance to coke formation and sintering in the dry reforming of methane due to their hierarchical porous structure, well dispersed metallic nickel species, more basic sites and strong metal-support interaction effect. Electronic supplementary information (ESI) available: Experimental details, XRD patterns, SEM images, and TEM images. See DOI: 10.1039/c3nr33921a

  4. Characterization of Ni and W co-loaded SBA-15 catalyst and its hydrogen production catalytic ability on ethanol steam reforming reaction

    Science.gov (United States)

    Kim, Dongjin; Kwak, Byeong Sub; Min, Bong-Ki; Kang, Misook

    2015-03-01

    This study evaluated the application of advanced bimetallic catalytic species of Ni and W to effectively produce hydrogen gases from ethanol steam reforming. The highest reactivity was achieved using the Ni0.95W0.05/SBA-15 catalyst. The maximum H2 production and ethanol conversion of 90% and 85%, respectively, were obtained for 0.4 g catalyst at 600 °C after 10 h with a EtOH:H2O ratio of 1:3 and a gas hourly space velocity of 6000 h-1. This highlights a synergy between the Ni and W loading on SBA-15 during ethanol steam reforming that occurs through the inhibition of Ni particle agglomeration and consequent decrease in catalytic deactivation. Additionally, the supplied W ingredients promoted CO2 selectivity, which was generated from the CO-water gas shift reaction.

  5. Carbon Dioxide Dry Reforming of Glycerol for Hydrogen Production using Ni/ZrO2 and Ni/CaO as Catalysts

    Directory of Open Access Journals (Sweden)

    Nur Nabillah Mohd Arif

    2016-08-01

    Full Text Available Glycerol, byproduct from the biodiesel production can be effectively utilized as the promising source of synthesis gas (syngas through a dry reforming reaction. Combination of these waste materials with greenhouse gases which is carbon dioxide (CO2 will help to reduce environmental problem such as global warming. This dry reforming reaction has been carried out in a fixed bed batch reactor at 700 °C under the atmospheric pressure for 3 hours. In this experiment, reforming reaction was carried out using Nickel (Ni as based catalyst and supported with zirconium (ZrO2 and calcium (CaO oxides. The catalysts were prepared by wet impregnation method and characterized using Bruanaer-Emmett-Teller (BET surface area, Scanning Electron Microscopy (SEM, X-ray Diffraction (XRD, Thermo Gravimetric (TGA, and Temperature Programmed Reduction (TPR analysis. Reaction studies show that 15% Ni/CaO give the highest hydrogen yield and glycerol conversion that peaked at 24.59% and 30.32%, respectively. This result is verified by XRD analysis where this catalyst shows low crystallinity and fine dispersion of Ni species resulted in high specific surface area which gives 44.93 m2/g that is validated by BET.  Copyright © 2016 BCREC GROUP. All rights reserved Received: 21st January 2016; Revised: 24th February 2016; Accepted: 29th February 2016 How to Cite: Arif, N.M.M., Vo, D.V.N., Azizan,M.T., Abidin S.Z. (2016. Carbon Dioxide Dry Reforming of Glycerol for Hydrogen Production using Ni/ZrO2 and Ni/CaO as Catalysts. Bulletin of Chemical Reaction Engineering & Catalysis, 11 (2: 200-209 (doi:10.9767/bcrec.11.2.551.200-209 Permalink/DOI: http://dx.doi.org/10.9767/bcrec.11.2.551.200-209

  6. Researching the Possibility of Creating Highly Effective Catalysts for the Thermochemical Heat Regeneration and Hydrocarbon Reforming

    Science.gov (United States)

    2006-11-01

    oxide films or chemical pickling . Mechanical treatment of the samples (50x12 mm plates) was performed in the ball mill under the following conditions... pickling (temperature 90 - 160°C, time – 0.01 -1.0 h, alkali NaOH concentration – 10-30 % by mass) on surface variation has been studied on X15Ю5...using Bulat installation) on: • Ni-Cr alloy of Х15Ю5 grade, 100 x 100 mm in size – for measurement of catalytic activity; • Titanium foil – for

  7. Microscopic characterization of changes in the structure of KCo/CeO{sub 2} catalyst used in the steam reforming of ethanol

    Energy Technology Data Exchange (ETDEWEB)

    Słowik, Grzegorz, E-mail: Grzegorz.Slowik@poczta.umcs.lublin.pl; Greluk, Magdalena; Machocki, Andrzej

    2016-04-15

    The cobalt catalyst with a support of CeO{sub 2} and potassium promoted (KCo/CeO{sub 2}) was prepared by an impregnation method and used in the steam reforming of ethanol (SRE). The catalyst was characterized in its initial oxide form and after its work in the SRE by electron microscopy and EDS methods. Microscopic characterization of the catalyst allowed for identification of the active phase (in Co{sub 3}O{sub 4} form) and the CeO{sub 2} support phase (O-terminated), existing in the fresh catalyst, and also the active phase (at various forms, Co and CoO), support phase as well as various carbonaceous phases in the used catalyst. STEM-EDS studies allowed to determine the distribution of constituent elements in the catalyst before reaction and besides of them - also carbon deposit after the SRE. Microscopic studies of used catalyst proved that it was largely covered with carbonaceous deposit which was the main reason of deactivation of the catalyst. Carbon deposit growing during the reaction causes destruction of the support and the active phase into smaller particles which are sunked in the carbonaceous structures. - Highlights: • CeO{sub 2} and K promoter do not prevent cobalt catalyst from carbon formation in the SRE. • Carbon deposit was present in three forms: fibrous, encapsulates, partly surrounding. • Two types of carbon deposit structures: amorphous and hexagonal graphite were found. • Metallic cobalt and ceria support crystallites are present with K in fibrous carbon. • Cobalt active phase is present under SRE conditions as metallic Co and CoO.

  8. Electro-oxidation of ethanol on ternary non-alloyed Pt-Sn-Pr/C catalysts

    Science.gov (United States)

    Corradini, Patricia G.; Antolini, Ermete; Perez, Joelma

    2015-02-01

    Ternary Pt-Sn-Pr/C (70:10:20), (70:15:15) and (45:45:10) electro-catalysts were prepared by a modified formic acid method, and their activity for the ethanol oxidation reaction (EOR) was compared with that of Pt-Pr/C catalysts prepared by the same methods and that of commercial Pt-Sn/C (75:25) and Pt/C catalysts. Among all the catalysts, the Pt-Sn-Pr/C (45:45:10) catalyst presented both the highest mass activity and the highest specific activity. The steady state electrochemical stability of ternary Pt-Sn-Pr catalysts increased with the surface Sn/Pt atomic ratio. Following repetitive potential cycling (RPC), the activity for ethanol oxidation of Pt-Sn-Pr/C catalysts with high surface Sn/Pt atomic ratio was considerably higher than that of the corresponding as-prepared catalysts, and increased with increasing the Sn/Pt ratio. The increase of the EOR mass activity following RPC was ascribed to the increase of either the specific activity (for the Pt-Sn-Pr/C (70:15:15) catalyst) or the electrochemically active surface area (for the Pt-Sn-Pr/C (45:45:10) catalyst). Dissolution of Sn and Pr oxides from Pt-Sn-Pr/C catalyst surface was observed following RPC.

  9. Mathematical Modelling of Catalytic Fixed-Bed Reactor for Carbon Dioxide Reforming of Methane over Rh/Al2O3 Catalyst

    Directory of Open Access Journals (Sweden)

    New Pei Yee

    2008-04-01

    Full Text Available A one-dimensional mathematical model was developed to simulate the performance of catalytic fixed bedreactor for carbon dioxide reforming of methane over Rh/Al2O3 catalyst at atmospheric pressure. The reactionsinvolved in the system are carbon dioxide reforming of methane (CORM and reverse water gas shiftreaction (RWGS. The profiles of CH4 and CO2 conversions, CO and H2 yields, molar flow rate and molefraction of all species as well as reactor temperature along the axial bed of catalyst were simulated. In addition,the effects of different reactor temperature on the reactor performance were also studied. The modelscan also be applied to analyze the performances of lab-scale micro reactor as well as pilot-plant scale reactorwith certain modifications and model verification with experimental data. © 2008 BCREC UNDIP. All rights reserved.[Received: 20 August 2008; Accepted: 25 September 2008][How to Cite: N.A.S. Amin, I. Istadi, N.P. Yee. (2008. Mathematical Modelling of Catalytic Fixed-Bed Reactor for Carbon Dioxide Reforming of Methane over Rh/Al2O3 Catalyst. Bulletin of Chemical Reaction Engineering and Catalysis, 3 (1-3: 21-29. doi:10.9767/bcrec.3.1-3.19.21-29

  10. Mathematical Modelling of Catalytic Fixed-Bed Reactor for Carbon Dioxide Reforming of Methane over Rh/Al2O3 Catalyst

    Directory of Open Access Journals (Sweden)

    Nor Aishah Saidina Amin

    2010-10-01

    Full Text Available A one-dimensional mathematical model was developed to simulate the performance of catalytic fixed bed reactor for carbon dioxide reforming of methane over Rh/Al2O3 catalyst at atmospheric pressure. The reactions involved in the system are carbon dioxide reforming of methane (CORM and reverse water gas shift reaction (RWGS. The profiles of CH4 and CO2 conversions, CO and H2 yields, molar flow rate and mole raction of all species as well as reactor temperature along the axial bed of catalyst were simulated. In addition, the effects of different reactor temperature on the reactor performance were also studied. The models can also be applied to analyze the performances of lab-scale micro reactor as well as pilot-plant scale reactor with certain modifications and model verification with experimental data. © 2008 BCREC UNDIP. All rights reserved.[Received: 20 August 2008; Accepted: 25 September 2008][How to Cite: N.A.S. Amin, I. Istadi, N.P. Yee. (2008. Mathematical Modelling of Catalytic Fixed-Bed Reactor for Carbon Dioxide Reforming of Methane over Rh/Al2O3 Catalyst. Bulletin of Chemical Reaction Engineering and Catalysis, 3 (1-3: 21-29.  doi:10.9767/bcrec.3.1-3.7120.21-29][How to Link/DOI: http://dx.doi.org/10.9767/bcrec.3.1-3.7120.21-29 || or local: http://ejournal.undip.ac.id/index.php/bcrec/article/view/7120

  11. Performance of Pt-Co alloys and CoTPP catalysts for the reduction of oxygen in AFC

    Energy Technology Data Exchange (ETDEWEB)

    Kiros, Y. [Royal Institute of Technology, Stockholm (Sweden); Sampathrajan, A.; Ramanathan, M. [Tamil Nadu Agricultural Univ., Coimbatore (India)

    1996-12-31

    One of the primary problems of the oxygen reduction reaction (ORR) for especially low and medium temperature fuel cells such as AFC, PEFC and PAFC is the high activation overpotential. This high overpotential is due to the complicated nature of the ORR and the morphological properties of the catalyst particles. High catalyst dispersion on the carbon support and small particle sizes, non-agglomeration and/or non-dissolution of the electrocatalyst is desired for the long-term operation of the electrodes. In this study electrodes were tested at different temperatures and concentrations in order to substantiate their influences on the activity and stability of the electrocatalysts, i.e.; cobalt tetraphenylporphyrin (CoTPP) and alloys of platinum and cobalt.

  12. Methanol steam reforming over Cu/CeO2 catalysts: influence of zinc addition

    Directory of Open Access Journals (Sweden)

    Franco Tonelli

    2011-01-01

    Full Text Available Methanol steam reforming reaction was studied over Cu(5 wt.%/CeO2 with and without the presence of Zn. The Zn addition decreased the Cu+2 reducibility and increased the oxygen mobility of ceria. The main products were CO2 and H2 with small amount of CO. Selectivity to CO decreased with the Zn addition and it was lower at lower reaction temperatures and lower space velocities. At 230 ºC and W/F MeOH = 648 g min mol-1 selectivities to H2 and to CO2 were 100% on Zn/Cu/Ce. The catalytic results indicated that CO was mainly a secondary product formed from reverse water gas shift reaction.

  13. Dry reforming of methane on Ni-Mg-Al nano-spheroid oxide catalysts prepared by the sol-gel method from hydrotalcite-like precursors

    Science.gov (United States)

    González, Albert R.; Asencios, Yvan J. O.; Assaf, Elisabete M.; Assaf, José M.

    2013-09-01

    Nanocapsular hydrotalcites (layered double hydroxides - LDHs) were synthesized by the sol-gel method and used as precursors of nano-structured mixed oxides containing various nickel loads (4, 15 and 19 wt%). The best conditions for the preparation of LDHs were analyzed and the structures of the resulting mixed oxides were studied. The optimal nickel load and calcining conditions were optimized. Finally, the resulting catalysts were tested in the dry reforming of methane for 8 h at 800 °C under atmospheric pressure. These materials showed high activity and stability, and the coke deposits were minimal on the catalyst prepared under optimal conditions (19 wt% nickel load and thermal treatment at 650 °C). The best catalyst formed amorphous carbon, which seems not to be prejudicial to the reaction.

  14. Stabilization of Hydrogen Production via Methanol Steam Reforming in Microreactor by Al2O3 Nano-Film Enhanced Catalyst Adhesion.

    Science.gov (United States)

    Jeong, Heondo; Na, Jeong-Geol; Jang, Min Su; Ko, Chang Hyun

    2016-05-01

    In hydrogen production by methanol steam reforming reaction with microchannel reactor, Al2O3 thin film formed by atomic layer deposition (ALD) was introduced on the surface of microchannel reactor prior to the coating of catalyst particles. Methanol conversion rate and hydrogen production rate, increased in the presence of Al2O3 thin film. Over-view and cross-sectional scanning electron microscopy study showed that the adhesion between catalyst particles and the surface of microchannel reactor enhanced due to the presence of Al2O3 thin film. The improvement of hydrogen production rate inside the channels of microreactor mainly came from the stable fixation of catalyst particles on the surface of microchannels.

  15. Autothermal reforming of methane over Ni catalysts supported over ZrO2-CeO2-Al2O3

    Institute of Scientific and Technical Information of China (English)

    Xiulan Cai; Yuanxing Cai; Weiming Lin

    2008-01-01

    Ni catalysts supported on Al2O3, ZrO2-Al2O3, CeO2-Al2O3 and ZrO2-CeO2-Al2O3 were prepared by co-precipitation method, and their catalytic performances for autothermal reforming of methane to hydrogen were investigated.The Ni-supported catalysts were characterized by XRD, TPR and XPS. The relationship between the structures and catalytic activities of the catalysts was discussed. The results showed that the catalytic activity and stability of the Ni/ZrO2-CeO2-Al2O3 catalyst was better than those of other catalysts with the highest CH4 conversion, H2/CO and H2/COx ratio at 750 ℃. The cat-alyst showed a little deactivation along the reaction time during its 72 h on stream with the mean deactivation rate of 0.08%/h. The catalytic performance of the Ni/ZrO2-CeO2-Al2O3 catalyst was also affected by reaction temperature, nO2: nCH4 molar ratio and nH2O : nCH4 molar ratio. TPR, XRD and XPS measurements indicated that the formation of ZrO2-CeO2 solid solu-tion could improve the dispersion of NiO, and inhibit the formation of NiAl2O4, and thus significantly promoted the catalytic activity of the Ni/ZrO2-CeO2-Al2O3 catalyst.

  16. Enhancing the cyclability of Li-O2 batteries using PdM alloy nanoparticles anchored on nitrogen-doped reduced graphene as the cathode catalyst

    Science.gov (United States)

    Leng, Limin; Li, Jing; Zeng, Xiaoyuan; Song, Huiyu; Shu, Ting; Wang, Haishui; Liao, Shijun

    2017-01-01

    An efficient ORR/OER catalyst was developed by anchoring highly dispersed bimetallic PdM (M = Fe, Co, Ni) alloy nanoparticles on nitrogen-doped reduced graphene oxide (N-rGO). This new type of catalyst exhibited excellent ORR/OER activity, and the addition of transition metals also significantly improved catalytic stability, with the catalyst containing Fe (PdFe/N-rGO) exhibiting the best stability. A battery using this PdFe/N-rGO catalyst was capable of long-term stable cycling for 400 cycles (2000 h) with a limited capacity of 1000 mAh g-1 at 400 mA g-1, which was much longer than a battery with Pd/N-rGO as the catalyst (only 80 cycles, 400 h). We attribute the high performance of these catalysts to the high surface area of N-rGO, the anchoring of highly dispersed Pd alloy nanoparticles, and the prevention of Pd alloy nanoparticle aggregation and dissolution by the presence of the transition metals.

  17. Partial oxidation and CO{sub 2} reforming of methane on Pt/Al{sub 2}O{sub 3}, Pt/ZrO{sub 2}, and Pt/Ce-ZrO{sub 2} catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Mattos, L.V.; Noronha, F.B. [Instituto Nacional de Tecnologia-INT, Av. Venezuela 82, Rio de Janeiro CEP 20081-310 (Brazil); Rodino, E.; Passos, F.B. [Departamento de Engenharia Quimica e Programa de Pos-Graduacao em Quimica Organica, Universidade Federal Fluminense, Rua Passos da Patria, 156, Niteroi CEP 24210-230 (Brazil); Resasco, D.E. [School of Chemical Engineering and Materials Science, University of Oklahoma, 100 East Boyd Street, Norman, OK 73019 (United States)

    2003-09-15

    The partial oxidation and CO{sub 2} reforming of methane were studied on Pt/Al{sub 2}O{sub 3}, Pt/ZrO{sub 2}, and Pt/Ce-ZrO{sub 2} catalysts. The reducibility and the oxygen transfer capacity were evaluated by oxygen storage capacity (OSC). The effect of the support on the cleaning mechanism of the catalyst surface was investigated by the sequence of CH{sub 4}/O{sub 2} and CH{sub 4}/CO{sub 2} pulses. The Pt/Ce-ZrO{sub 2} catalyst showed the highest stability on both partial oxidation and CO{sub 2} reforming of methane. The results were explained by the higher reducibility and oxygen storage/release capacity of Pt/Ce-ZrO{sub 2} catalysts, which allowed a continuous removal of carbonaceous deposits from the active sites, favoring the stability of the catalysts, as revealed by the CH{sub 4}/O{sub 2} and CH{sub 4}/CO{sub 2} pulses. For Pt/Al{sub 2}O{sub 3} and Pt/ZrO{sub 2} catalysts, the increase of carbon deposits around or near the metal particle inhibits the CO{sub 2} dissociation on CO{sub 2} reforming of methane. This effect on the CO{sub 2} reforming of methane affects the partial oxidation of methane, which comprehends two steps: combustion of methane and CO{sub 2} and steam reforming of unreacted methane.

  18. 重整预加氢催化剂国内外技术进展%Technology progress of pre-hydrotreating catalyst for reforming unit

    Institute of Scientific and Technical Information of China (English)

    王广胜; 米多; 王伟峰

    2011-01-01

    催化重整预加氢催化剂主要是由载体和金属活性组分组成,最常用的预加氢催化剂的金属组分是Co-Mo、Ni-Mo、Ni-W体系.主要论述了催化重整预加氢催化剂的国内外技术进展,着重论述了国内重整预加氢催化剂的性质、特点及研发单位,提出了重整预加氢催化剂的发展方向,催化重整预加氢催化剂对直馏汽油要有良好的适应性,空速高,反应温度低,活性稳定性好,能够满足工业上长周期运转的需要.%The pre-hydrotreating catalyst for reforming unit are made up of carrier and metal active component,the most commonly used of metal active component for pre-hydrotreating are Co-Mo, Ni-Mo, and Ni-W. The article summarized the technology progress of pre-hydrotreating catalyst for refor-ming unit at home and abroad,emphatically discussed the activity and scientific research situation,put forward the future developing direction of pre-hydrotreating catalyst for reforming unit. The pre-hy-drotreating catalyst should have high space velocity, low reaction temperature,high activity and stabili-ty in distilled gasoline pre-hydrogenation and could meet the need of long running production.

  19. Alloyed Ni-Fe nanoparticles as catalysts for NH3 decomposition

    DEFF Research Database (Denmark)

    Simonsen, Søren Bredmose; Chakraborty, Debasish; Chorkendorff, Ib

    2012-01-01

    temperatures and a low NH3-to-H2 ratio, the catalytic activity of the best Ni-Fe/Al2O3 catalyst was found to be comparable or even better to that of a more expensive Ru-based catalyst. Small Ni-Fe nanoparticle sizes are crucial for an optimal overall NH3 conversion because of a structural effect favoring...

  20. Performance of metal alloys as hydrogen evolution reaction catalysts in a microbial electrolysis cell

    NARCIS (Netherlands)

    Jeremiasse, A.W.; Bergsma, J.; Kleijn, J.M.; Saakes, M.; Buisman, C.J.N.; Cohen Stuart, M.A.; Hamelers, H.V.M.

    2011-01-01

    H2 can be produced from organic matter with a microbial electrolysis cell (MEC). To decrease the energy input and increase the H2 production rate of an MEC, a catalyst is used at the cathode. Platinum is an effective catalyst, but its high costs stimulate searching for alternatives, such as non-nobl

  1. NiO-Ce0.5Zr0.5O2 catalysts prepared by citric acid method for steam reforming of ethanol

    Institute of Scientific and Technical Information of China (English)

    YE Jilei; WANG Yang; LIU Yuan

    2008-01-01

    NiO-Ce0.5Zr0.5O2catalysts were prepared by citrate method and used for hydrogen production from steam reforming of ethanol (SRE). The effect of nickel content and space velocity on the catalytic performance was investigated. The prepared catalysts were character-ized with XRD and thermal analysis techniques. 20%NiO-Ce0.5Zr0.5O2 catalyst was very active and selective for hydrogen production via SRE, in which ethanol conversion of 100% could be obtained with feed component of 20% (H2O+EtOH) and 80% N2, water/ethanol of 3/1 in molar ratio at 350 ℃. Also, the catalyst showed good stability for anti-sintering and carbon-resistance. The XRD illuminated that both NiO and Ce0.5Zr0.5O2 crystal sizes were very small in NiO-Ce0.5Zr0.5O2 catalyst, and Ce0.5Zr0.5O2 solid solution was formed.

  2. Effect of CeO₂ addition to Al₂O₃ supports for Pt catalysts on the aqueous-phase reforming of glycerol.

    Science.gov (United States)

    Rahman, M M; Church, Tamara L; Minett, Andrew I; Harris, Andrew T

    2013-06-01

    A series of Pt catalysts supported on Al₂O₃ that was doped with different amounts of CeO₂ was developed, characterized, and tested in the aqueous-phase reforming (APR) of glycerol to H₂. Catalyst 3Pt/3CeAl, which bore 3 wt% Pt on a support that contained 3 wt % CeO₂, showed the highest carbon conversion to gas (85%) and the highest H₂ yield (80%) for a feedstock of 1 wt% glycerol in water at 240 °C and 40 bar. A CeO₂/Al₂O₃ support with only 1 wt% Pt also showed high H₂ selectivity and carbon conversion to gas, as well as a much lower CH₄ yield than the benchmark 3Pt/Al catalyst, clearly demonstrating that doping the support with 3 wt% CeO2 improved the APR of glycerol. H₂ chemisorption results showed that the highest metal dispersion (58%) and active surface area (4.3 m(2)g(-1)) were achieved for the support that contained 3 wt% CeO₂, and this effect appeared to be primarily responsible for the high H₂ yield and carbon conversion to gas. No CO was observed in the product gas; therefore, this gas could potentially be used directly in proton exchange membrane fuel cells. Thus, including CeO₂ in the Al₂O₃ catalyst support enhanced both the activity and selectivity towards H₂ of a Pt catalyst for the APR of glycerol.

  3. Preparation of low-platinum-content platinum-nickel, platinum-cobalt binary alloy and platinum-nickel-cobalt ternary alloy catalysts for oxygen reduction reaction in polymer electrolyte fuel cells

    Science.gov (United States)

    Li, Mu; Lei, Yanhua; Sheng, Nan; Ohtsuka, Toshiaki

    2015-10-01

    A series of low-platinum-content platinum-nickel (Pt-Ni), platinum-cobalt (Pt-Co) binary alloys and platinum-nickel-cobalt (Pt-Ni-Co) ternary alloys electrocatalysts were successfully prepared by a three-step process based on electrodeposition technique and studied as electrocatalysts for oxygen reduction reaction (ORR) in polymer-electrolyte fuel cells. Kinetics of ORR was studied in 0.5 M H2SO4 solution on the Pt-Ni, Pt-Co and Pt-Ni-Co alloys catalysts using rotating disk electrode technique. Both the series of Pt-Ni, Pt-Co binary alloys and the Pt-Ni-Co ternary alloys catalysts exhibited an obvious enhancement of ORR activity in comparison with pure Pt. The significant promotion of ORR activities of Pt-Ni and Pt-Co binary alloys was attributed to the enhancement of the first electron-transfer step, whereas, Pt-Ni-Co ternary alloys presented a more complicated mechanism during the electrocatalysis process but a much more efficient ORR activities than the binary alloys.

  4. Unsupported NiPt alloy metal catalysts prepared by water-in-oil (W/O) microemulsion method for methane cracking

    KAUST Repository

    Zhou, Lu

    2016-05-18

    Unsupported NiPt metal catalyst with Ni/Pt molar ratio of 88/12 is prepared by water-in-oil (W/O) microemulsion method in this study. Compared to monometallic Ni and Pt catalysts, the NiPt catalyst exhibits superior activity and stability for methane cracking. By XRD (X-ray powder diffraction), XPS (X-ray photoelectron spectroscopy) and TEM (Transmission electron microscopy) analyses, the formation of Ni(0)Pt(0) alloy is believed to be the main reason for the reactivity improvement of this catalyst. Carbon nano tube (CNT) with Ni(0)Pt(0) particles anchored on the top of tube are found for the NiPt catalyst. © 2016 Elsevier Ltd.

  5. Kinetics of catalytic reforming with Pt-Sn catalyst; Modelisation cinetique du reformage catalytique sur catalyseur Pt-Sn/Al{sub 2}O{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Cochegrue, H.

    2001-04-01

    Catalytic Reforming is one of the key processes for petrol refining as it produces gasoline with a high octane number and it is a main source of hydrogen. Refiners are asking for more accurate models in order to optimise their plants. An innovative methodology called 'Single Events' is very different from the classical empirical models because it takes into account the various reaction intermediates and reaction pathways. Some hypotheses based on the relative stability of the carbo-cations allow to get a small number of parameters, which are independent of the composition of the feedstock used. The main target of this work was to apply this methodology to the Catalytic Reforming. The single event network had to be first reduced to a late lumped reaction scheme, which incorporates the detailed knowledge of the elementary network while the intermediates and the reaction pathways are reduced: it can be applied now to naphtha feedstock, although the detailed composition is not yet well known. A pilot unit of Catalytic Reforming, which is representative of the industrial processes, was first designed for the kinetic experiments. Experiments with technical heptane were conducted with a fresh catalyst, which was cocked first, and with a used catalyst from a refinery plant. This latter was difficult to use because of its fast deactivation. However, the results obtained allowed to study the influence of the experimental parameters and of the poisoning by iron, and to estimate some of the main kinetic parameters of the model. (author)

  6. Production of hydrogen by steam reforming of C3 organics over Pd-Cu/{gamma}-Al{sub 2}O{sub 3} catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Resini, Carlo; Berardinelli, Silvia; Busca, Guido [Dipartimento di Ingegneria Chimica e Processo, Universita di Genova, P.le J.F. Kennedy, 1, 16129 Genova (Italy); Arrighi, Laura; Riani, Paola; Marazza, Rinaldo [Dipartimento di Chimica e Chimica Industriale, Universita di Genova, Via Dodecaneso 31, 16146 Genova (Italy); Concepcion Herrera Delgado, Maria; Angeles Larrubia Vargas, Maria; Alemany, Luis J. [Departamento de Ingenieria Quimica, Universidad de Malaga, 29071 Malaga (Spain)

    2006-01-15

    The conversion of the C3 organics propane, propene, isopropanol and acetone in auto-thermal and endothermic steam reforming conditions has been investigated over a Pd-Cu/Al{sub 2}O{sub 3} catalyst in a flow reactor. Although several reactions may occur at lower temperatures (like dehydrogenation, oxidative dehydrogenation, dehydration and combustion), steam reforming of 2-propanol, acetone and propane only start above 850K and with incomplete selectivity. Cracking and methanation lower the selectivity to CO{sub x} and hydrogen. The C-C bond breaking step is considered to be rate determining. The presence of an oxygenated functional group is consequently not useful to lower reaction temperature, although the use of the alcohol and the ketone may be interesting because of the renewable nature of these reactants. Steam reforming of propene starts at significantly lower temperature (600-700K) and is by far the most selective to CO{sub x} and hydrogen over our catalyst. (author)

  7. Steam reforming of bio-ethanol over Ni on Ce-ZrO2 support: Influence of redox properties on the catalyst reactivity

    Directory of Open Access Journals (Sweden)

    Sumittra Charojrochkul

    2006-11-01

    Full Text Available The steam reforming of ethanol over Ni on Ce-ZrO2 support, (Ni/ Ce-ZrO2 were studied. The catalyst provides significantly higher reforming reactivity and excellent resistance toward carbon deposition compared to Ni/Al2O3 under the same conditions. At the temperature above 800ºC, the main products from the reforming processes over Ni/Ce-ZrO2 were H2, CO, and CO2 with small amount of CH4 depending on the inlet ethanol/steam and oxygen/ethanol ratios, whereas high hydrocarbon compounds i.e., C2H4 and C2H6 were also observed from the reforming of ethanol over Ni/Al2O3 in the range of conditions studied (700- 1000ºC.These excellent ethanol reforming performances of Ni/Ce-ZrO2 in terms of stability, reactivity and product selectivities are due to the high redox property of Ce-ZrO2. During the ethanol reforming process, in addition to the reactions on Ni surface, the gas-solid reactions between the gaseous components presented in the system (C2H5OH, C2H6, C2H4, CH4, CO2, CO, H2O, and H2 and the lattice oxygen (Ox on Ce-ZrO2 surface also take place. Among these redox reactions, the reactions of adsorbed surface hydrocarbons with the lattice oxygen (Ox (CnHm + Ox → nCO + m/2(H2 + Ox-n can eliminate the formation of high hydrocarbons (C2H6 and C2H4, which easily decompose and form carbon species on Ni surface (CnHm→ nC + m/2H2.

  8. Catalytic Hydrogenation of Levulinic Acid in Water into g-Valerolactone over Bulk Structure of Inexpensive Intermetallic Ni-Sn Alloy Catalysts

    Directory of Open Access Journals (Sweden)

    Rodiansono Rodiansono

    2015-07-01

    Full Text Available A bulk structure of inexpensive intermetallic nickel-tin (Ni-Sn alloys catalysts demonstrated highly selective in the hydrogenation of levulinic acid in water into g-valerolactone. The intermetallic Ni-Sn catalysts were synthesized via a very simple thermochemical method from non-organometallic precursor at low temperature followed by hydrogen treatment at 673 K for 90 min. The molar ratio of nickel salt and tin salt was varied to obtain the corresponding Ni/Sn ratio of 4.0, 3.0, 2.0, 1.5, and 0.75. The formation of Ni-Sn alloy species was mainly depended on the composition and temperature of H2 treatment. Intermetallics Ni-Sn that contain Ni3Sn, Ni3Sn2, and Ni3Sn4 alloy phases are known to be effective heterogeneous catalysts for levulinic acid hydrogenation giving very excellence g-valerolactone yield of >99% at 433 K, initial H2 pressure of 4.0 MPa within 6 h. The effective hydrogenation was obtained in H2O without the formation of by-product. Intermetallic Ni-Sn(1.5 that contains Ni3Sn2 alloy species demonstrated very stable and reusable catalyst without any significant loss of its selectivity. © 2015 BCREC UNDIP. All rights reserved. Received: 26th February 2015; Revised: 16th April 2015; Accepted: 22nd April 2015  How to Cite: Rodiansono, R., Astuti, M.D., Ghofur, A., Sembiring, K.C. (2015. Catalytic Hydrogenation of Levulinic Acid in Water into g-Valerolactone over Bulk Structure of Inexpensive Intermetallic Ni-Sn Alloy Catalysts. Bulletin of Chemical Reaction Engineering & Catalysis, 10 (2: 192-200. (doi:10.9767/bcrec.10.2.8284.192-200Permalink/DOI: http://dx.doi.org/10.9767/bcrec.10.2.8284.192-200  

  9. Ni-loaded nanocrystalline ceria-zirconia solid solutions prepared via modified Pechini route as stable to coking catalysts of CH4 dry reforming

    Directory of Open Access Journals (Sweden)

    Sadykov Vladislav A.

    2016-01-01

    Full Text Available Mixed nanocrystalline Ce-Zr-O oxides (Ce/Zr = 1 or 7/3 were prepared by modified Pechini route using ethylene glycol solutions of metal salts. Detailed characterization of their real structure and surface properties by X-ray diffraction on synchrotron radiation with the full-profile Rietveld analysis, high resolution electron microscopy with elemental analysis, Raman spectroscopy, UV-Vis and X-ray photoelectron spectroscopy revealed a high homogeneity of cations distribution in nanodomains resulting in stabilization of disordered cubic phase. This provides a high dispersion of NiO loaded on these mixed oxides by wet impregnation, a high reactivity and mobility of oxygen in these catalysts and strong interaction of Ni with support in the reduced state. This helps to achieve a high activity and coking stability of developed catalysts in CH4 dry reforming in feeds with CH4 concentration up to 15% and CH4/CO2 ratio =1.

  10. A series of copper-free ternary oxide catalysts ZnAlCex used for hydrogen production via dimethyl ether steam reforming

    Science.gov (United States)

    Zhang, Lijie; Meng, Ming; Wang, Xiaojing; Zhou, Shuang; Yang, Lijuan; Zhang, Tianyong; Zheng, Lirong; Zhang, Jing; Hu, Tiandou

    2014-12-01

    Ce-substituted ternary oxide catalysts ZnAlCex were prepared and employed in dimethyl ether steam reforming (DME SR) to produce hydrogen. XRD, XAFS (XANES & EXAFS), H2O-TPD, CH3OH-TPD and TPSR techniques were used for catalyst characterization. It is found that the catalytic performance of these catalysts is dependent on Ce content. The catalyst containing 20 wt% CeO2 exhibits the best catalytic performance. Its calculated TOF (0.034 s-1) is nearly three times to that of ZnAlO. The kinetic results reveal that the addition of 20 wt% CeO2 to ZnAlCex greatly decreases the apparent activation energy (Ea) of DME SR, due to the formation of new reaction sites such as Ce4+-O-Zn2+ linkages. XRD and EXAFS analyses indicate that Ce addition can not only decrease the crystallite size of ZnO and ZnAl2O4, but also tune the relative contents of them. The results of H2O-TPD and CH3OH-TPD show that Ce addition can lower H2 desorption temperature, which accounts well for the better catalytic performance of ZnAlCex. It is worth noting that the Zn-based catalysts display much lower CO selectivity than the Cu-based one, especially the Ce-substituted ZnAlCex. Start-off durability tests demonstrate that this series of catalysts also possess high catalytic stability.

  11. Influence of silica–alumina support ratio on H2 production and catalyst carbon deposition from the Ni-catalytic pyrolysis/reforming of waste tyres

    Science.gov (United States)

    Zhang, Yeshui; Tao, Yongwen; Huang, Jun; Williams, Paul

    2017-01-01

    The influence of catalyst support alumina–silica in terms of different Al2O3 to SiO2 mole ratios containing 20 wt.% Ni on the production of hydrogen and catalyst coke formation from the pyrolysis-catalysis of waste tyres is reported. A two-stage reactor system was used with pyrolysis of the tyres followed by catalytic reaction. There was only a small difference in the total gas yield and hydrogen yield by changing the Al2O3 to SiO2 mole ratios in the Ni-Al2O3/SiO2 catalyst. The 1:1 ratio of Al2O3:SiO2 ratio produced the highest gas yield of 27.3 wt.% and a hydrogen production of 14.0 mmol g-1tyre. Catalyst coke formation decreased from 19.0 to 13.0 wt.% as the Al2O3:SiO2 ratio was changed from 1:1 to 2:1, with more than 95% of the coke being filamentous-type carbon, a large proportion of which was multi-walled carbon nanotubes. Further experiments introduced steam to the second-stage reactor to investigate hydrogen production for the pyrolysis-catalytic steam reforming of the waste tyres using the 1:1 Al2O3/SiO2 nickel catalyst. The introduction of steam produced a marked increase in total gas yield from ~27 wt. % to ~58 wt.%; in addition, hydrogen production was increased to 34.5 mmol g-1 and there was a reduction in catalyst coke formation to 4.6 wt.%. PMID:28789599

  12. The impact of copper in LaNi{sub 1-x}Cu{sub x}O{sub 3} perovskite-like structures used as catalyst precursors for dry reforming of methane

    Energy Technology Data Exchange (ETDEWEB)

    Vlach, K.; Hoang, D.L.; Armbruster, U.; Martin, A. [Leibniz-Institut fuer Katalyse e.V. an der Universitaet Rostock (Germany)

    2013-11-01

    This work deals with the synthesis of perovskite-like catalyst precursors (LaNi{sub 1-x}Cu{sub x}O{sub 3} with x = 0, 0.2, 0.5, 0.8, 1). These precursors were used to catalyse the dry reforming of methane (DRM) reaction carried out at 973 K, CH{sub 4}/CO{sub 2} = 1 and a GHSV = 18,000 ml/g/h. The precursors were transformed during the course of the reaction to give Ni-Cu/La{sub 2}O{sub 3} solids. We found out that the activity increases with raising Ni content but small Cu admixture suppresses the coke formation substantially. XRD and TEM measurements showed that the transformation led to the formation of small metallic Ni and/or Cu particles. In addition also alloying can be observed. The best catalytic system with respect to activity and suppressed carbon deposition was Ni{sub 0.8}-Cu{sub 0.2}/La{sub 2}O{sub 3} (X{sub CH4} = 61%, X{sub CO2} = 67%). (orig.)

  13. Steam reforming of methane over Pt/Rh based wire mesh catalyst in single channel reformer for small scale syngas production

    DEFF Research Database (Denmark)

    Sigurdsson, Haftor Örn; Kær, Søren Knudsen

    2012-01-01

    The purpose of this study is to investigate a small scale steam methane reformer for syngas production for a micro combined heat and power (mCPH) unit under different operational conditions. The study presents an experimental analysis of the performance of a specially built single channel...... to evaluate the effect of flow maldistribution in a CPHE reformer stack on the CH4 conversion and H2 yield....

  14. Effect of Metal-Support Interactions in Ni/Al2O3 Catalysts with Low Metal Loading for Methane Dry Reforming

    Energy Technology Data Exchange (ETDEWEB)

    Ewbank, Jessica L.; Kovarik, Libor; Diallo, Fatoumata Z.; Sievers, Carsten

    2015-03-01

    Types of nickel sites as a function of preparation method have received much attention in the literature. In this work, two preparation methods, controlled adsorption and dry impregnation, are implemented to explore the effect of preparation method on catalytic nickel centers. For controlled adsorption, optimal synthesis conditions are identified using point of zero charge measurements, pH-precipitation experiments, and adsorption isotherms to prepare a catalyst with a high dispersion and strong metal support interactions. Metal support interactions influence the types of nickel sites formed. Thus, comparison of catalysts that differ primarily in metal support interactions, strong metal support interaction (controlled adsorption) and weak metal support interactions (dry impregnation), is of great interest. It is confirmed through characterization techniques; N2 physisorption, H2 chemisorption, temperature programmed reduction (TPR), transmission electron microscopy (TEM), and x-ray photoelectron spectroscopy (XPS) that the types of nickel sites formed are indeed strongly dependent on preparation method. Methane dry reforming reactivity studies are used to demonstrate the successful application of these catalysts and further probe the types of active centers present. Combustion analysis and XPS of spent catalysts reveal different amounts and nature of carbonaceous deposits as a function of the synthesis method.

  15. Hydrogen production via CO2 reforming of methane over ZrO2-Doped Ni/ZSM-5 nanostructured catalyst prepared by ultrasound assisted sequential impregnation method

    Science.gov (United States)

    Rahmani, Farhad; Haghighi, Mohammad; Vafaeian, Yaser; Estifaee, Pooya

    2014-12-01

    In our continuing effort to find the proper catalyst for CO2 reforming of methane, Ni(8%)/ZSM-5-ZrO2 with various zirconium loadings (0-15%) are synthesized via sonochemical method. All samples are characterized by XRD, FESEM, TEM, EDX, BET, FTIR and TPR-H2 techniques. The XRD results confirm existence of NiO, ZrO2 and ZSM-5 as crystalline phase in catalyst structure. FESEM images reveal small particle size of active metals and low numbers of agglomerations for Ni(8%)/ZrO2(5%)-ZSM-5. BET analysis shows that addition of ZrO2 to Ni/ZSM-5 decreases the surface area but Ni/ZrO2(5%)-ZSM-5 has the highest surface area. TEM analysis demonstrates high dispersion of Ni nano particles over the support. EDX depicts the best active metal dispersion for the catalyst with 5% zirconia loading. The TPR results prove that the metal-support interaction is enhanced by zirconia addition, indicating the better Ni dispersion. Apart from characterization, activity tests are performed and parameters such as effect of temperature, CO and H2 yields and H2/CO ratio are investigated. The results show that Ni(8%)/ZrO2(5%)-ZSM-5 has the best structural properties and the highest activity and stability in comparison with the other catalysts.

  16. Ni/SiO2 Catalyst Prepared with Nickel Nitrate Precursor for Combination of CO2 Reforming and Partial Oxidation of Methane: Characterization and Deactivation Mechanism Investigation

    Directory of Open Access Journals (Sweden)

    Sufang He

    2015-01-01

    Full Text Available The performance of Ni/SiO2 catalyst in the process of combination of CO2 reforming and partial oxidation of methane to produce syngas was studied. The Ni/SiO2 catalysts were prepared by using incipient wetness impregnation method with nickel nitrate as a precursor and characterized by FT-IR, TG-DTA, UV-Raman, XRD, TEM, and H2-TPR. The metal nickel particles with the average size of 37.5 nm were highly dispersed over the catalyst, while the interaction between nickel particles and SiO2 support is relatively weak. The weak NiO-SiO2 interaction disappeared after repeating oxidation-reduction-oxidation in the fluidized bed reactor at 700°C, which resulted in the sintering of metal nickel particles. As a result, a rapid deactivation of the Ni/SiO2 catalysts was observed in 2.5 h reaction on stream.

  17. Influence of Ce-precursor and fuel on structure and catalytic activity of combustion synthesized Ni/CeO{sub 2} catalysts for biogas oxidative steam reforming

    Energy Technology Data Exchange (ETDEWEB)

    Vita, Antonio, E-mail: antonio.vita@itae.cnr.it; Italiano, Cristina; Fabiano, Concetto; Laganà, Massimo; Pino, Lidia

    2015-08-01

    A series of nanosized Ni/CeO{sub 2} catalysts were prepared by Solution Combustion Synthesis (SCS) varying the fuel (oxalyldihydrazide, urea, carbohydrazide and glycerol), the cerium precursor (cerium nitrate and cerium ammonium nitrate) and the nickel loading (ranging between 3.1 and 15.6 wt%). The obtained powders were characterized by X-ray Diffraction (XRD), N{sub 2}-physisorption, CO-chemisorption, Temperature Programmed Reduction (H{sub 2}-TPR) and Scanning Electron Microscopy (SEM). The catalytic activity towards the Oxy Steam Reforming (OSR) of biogas was assessed. The selected operating variables have a strong influence on the nature of combustion and, in turn, on the morphological and structural properties of the synthesized catalysts. Particularly, the use of urea allows to improve nickel dispersion, surface area, particle size and reducibility of the catalysts, affecting positively the biogas OSR performances. - Highlights: • Synthesis of Ni/CeO{sub 2} nanopowders by quick and easy solution combustion synthesis. • The fuel and precursor drive the structural and morphological properties of the catalysts. • The use of urea as fuel allows to improve nickel dispersion, surface area and particle size. • Ni/CeO{sub 2} (7.8 wt% of Ni loading) powders synthesized by urea route exhibits high performances for the biogas OSR process.

  18. Effect of calcination temperature on structure and performance of Ni/TiO2-SiO2 catalyst for CO2 reforming of methane

    Institute of Scientific and Technical Information of China (English)

    Sanbing Zhang; Jiankang Wang; Xiaolai Wang

    2008-01-01

    The influence of calcination temperature on the structure and catalytic behavior of Ni/TiO2-SiO2 catalyst, for CO2 reforming of methane to synthesis gas under atmospheric pressure, was investigated. The results showed that the Ni/TiO2-SiO2 catalyst calcined at 700 ℃ had high and stable activity while the catalysts calcined at 550 and 850 ℃ had low and un-stable activity. Depending on the calcination temperature, one, two, or three of the following Ni-contalning species, NiO,Ni2.44Ti0.72Si0.07O4, and NiTiO3 were identified by combining the temperature programmed reduction (TPR) and X-ray diffraction (XRD) results. Their reducibility decreased in the sequence: NiO>Ni2.44Ti0.72Si0.07O4>NiTiO3. It suggests that high and stable activities observed over the Ni/TiO2-SiO2 catalyst calcined at 700 ℃ were induced by the formation of Ni2.44Ti0.72Si0.07O4 and smaller NiO species crystallite size.

  19. Catalytic features of Ni/Ba-Ce{sub 0.9}-Y{sub 0.1} catalyst to produce hydrogen for PCFCs by methane reforming

    Energy Technology Data Exchange (ETDEWEB)

    Frontera, P.; Modafferi, V.; Antonucci, P.L. [Dept. of Mechanics and Materials, Mediterranea University, Feo di Vito, 89060 Reggio Calabria (Italy); Frusteri, F.; Bonura, G.; Bottari, M.; Siracusano, S. [CNR-ITAE ' ' Nicola Giordano' ' , via S. Lucia sopra Contesse, 5 - 98126 Messina (Italy)

    2010-10-15

    Methane reforming in steam (SR), auto-thermal (ATR) and partial oxidation (POX) conditions over Ni/Ba-Ce{sub 0.9}-Y{sub 0.1} catalyst was investigated in the temperature range 500-700 C. Catalyst presents a satisfying activity in POX condition only. BCY carrier was not stable in the presence of CO{sub 2} and, irrespective of reaction conditions, it reacts with CO{sub 2} giving rise to the formation of BaCO{sub 3} and CeO{sub 2}. The very low activity observed in SR conditions was due to the negative role exerted by water strongly absorbed on catalyst surface, limiting so the accessibility and reduction state of Ni active sites. In POX condition catalyst is active and satisfying H{sub 2} yield can be reached by operating at T = 700 C. A significant reduction of coke formation was observed by operating in POX at 700 C. On the contrary, in ATR condition at the same reaction temperature huge amount of filamentous coke was observed. (author)

  20. Development of Ultra-Low Platinum Alloy Cathode Catalysts for PEM Fuel Cells

    Energy Technology Data Exchange (ETDEWEB)

    Popov, Branko N. [Univ. of South Carolina, Columbia, SC (United States). Dept. of Chemical Engineering; Weidner, John [Univ. of South Carolina, Columbia, SC (United States)

    2016-01-07

    The goal of this project is to synthesize a low cost PEM fuel cell cathode catalyst and support with optimized average mass activity, stability of mass activity, initial high current density performance under H2/air (power density), and catalyst and support stability able to meet 2017 DOE targets for electrocatalysts for transportation applications. Pt*/ACCS-2 catalyst was synthesized according to a novel methodology developed at USC through: (i) surface modification, (ii) metal catalyzed pyrolysis and (iii) chemical leaching to remove excess meal used to dope the support. Pt* stands for suppressed platinum catalyst synthesized with Co doped platinum. The procedure results in increasing carbon graphitization, inclusion of cobalt in the bulk and formation of non-metallic active sites on the carbon surface. Catalytic activity of the support shows an onset potential of 0.86 V for the oxygen reduction reaction (ORR) with well-defined kinetic and mass transfer regions and 2.5% H2O2 production. Pt*/ACCS-2 catalyst durability under 0.6-1.0 V potential cycling and support stability under 1.0-1.5 V potential cycling was evaluated. The results indicated excellent catalyst and support performance under simulated start-up/shut down operating conditions (1.0 – 1.5 V, 5000 cycles) which satisfy DOE 2017 catalyst and support durability and activity. The 30% Pt*/ACCS-2 catalyst showed high initial mass activity of 0.34 A/mgPGM at 0.9 ViR-free and loss of mass activity of 45% after 30,000 cycles (0.6-1.0 V). The catalyst performance under H2-air fuel cell operating conditions showed only 24 mV (iR-free) loss at 0.8 A/cm2 with an ECSA loss of 42% after 30,000 cycles (0.6-1.0 V). The support stability under 1.0-1.5 V potential cycling showed mass activity loss of 50% and potential loss of 8 mV (iR-free) at 1.5 A/cm2. The ECSA loss was 22% after 5,000 cycles. Furthermore, the Pt*/ACCS-2 catalyst showed an

  1. Hydrogenation of furfuryl alcohol to tetrahydrofurfuryl alcohol on NiB/SiO2 amorphous alloy catalyst

    Institute of Scientific and Technical Information of China (English)

    SONG Yun; LI Wei; ZHANG Minghui; TAO Keyi

    2007-01-01

    NiB/SiO2 amorphous alloy catalyst was prepared by power electroless plating method and characterized by induction coupled plasma (ICP),Brunauer-Emmett-Teller method (BET),transmission electron microscope (TEM)and X-ray diffraction (XRD) techniques.The catalytic performance of NiB/SiO2 was investigated for the hydrogenation of furfuryl alcohol (FA) to tetrahydrofurfuryl alcohol (THFA).The effects of operational conditions,such as reaction temperature,pressure,and stirring rate were carefully studied.The proper conditions were determined as the following:pressure 2.0 MPa,temperature 120℃ and stirring rate 550 r/min.A typical result with FA conversion of 99%and THFA selectivity of 100% was obtained under such conditions,which was close to that over Raney Ni.

  2. L-S mass transfer in G-L-S countercurrent magnetically stabilized bed with amorphous alloy SRNA-4 catalyst

    Institute of Scientific and Technical Information of China (English)

    Wei; Li; Baoning; Zong; Xiaofang; Li; Xiangkun; Meng; Jinli; Zhang

    2007-01-01

    Liquid-solid (L-S) mass transfer coefficients (Ks) were characterized in a gas-liquid-solid (G-L-S) three-phase countercurrent magnetically stabilized bed (MSB) using amorphous alloy SRNA-4 as the solid phase. Effects of superficial liquid velocity, superficial gas velocity, magnetic field strength, liquid viscosity and surface tension were investigated. Experimental results indicated that the external magnetic field increased Ks in three-phase MSB, as compared to those in conventional G-L-S fluidized beds; that Ks increased with magnetic field strength, superficial gas and liquid velocities and decreased with liquid viscosity and surface tension; and that Ks showed uniform axial and radial distributions except for small increases close to the wall. Dimensionless correlations were established to estimate Ks of the G-L-S countercurrent MSB using SRNA-4catalyst, with an average error of 3.6%.

  3. Catalytic activity of Pd-doped Cu nanoparticles for hydrogenation as a single-atom-alloy catalyst.

    Science.gov (United States)

    Cao, Xinrui; Fu, Qiang; Luo, Yi

    2014-05-14

    The single atom alloy of extended surfaces is known to provide remarkably enhanced catalytic performance toward heterogeneous hydrogenation. Here we demonstrate from first principles calculations that this approach can be extended to nanostructures, such as bimetallic nanoparticles. The catalytic properties of the single-Pd-doped Cu55 nanoparticles have been systemically examined for H2 dissociation as well as H atom adsorption and diffusion, following the concept of single atom alloy. It is found that doping a single Pd atom at the edge site of the Cu55 shell can considerably reduce the activation energy of H2 dissociation, while the single Pd atom doped at the top site or in the inner layers is much less effective. The H atom adsorption on Cu55 is slightly stronger than that on the Cu(111) surface; however, a larger nanoparticle that contains 147 atoms could effectively recover the weak binding of the H atoms. We have also investigated the H atom diffusion on the 55-atom nanoparticle and found that spillover of the produced H atoms could be a feasible process due to the low diffusion barriers. Our results have demonstrated that facile H2 dissociation and weak H atom adsorption could be combined at the nanoscale. Moreover, the effects of doping one more Pd atom on the H2 dissociation and H atom adsorption have also been investigated. We have found that both the doping Pd atoms in the most stable configuration could independently exhibit their catalytic activity, behaving as two single-atom-alloy catalysts.

  4. Catalytic reforming of toluene as tar model compound: effect of Ce and Ce-Mg promoter using Ni/olivine catalyst.

    Science.gov (United States)

    Zhang, Ruiqin; Wang, Huajian; Hou, Xiaoxue

    2014-02-01

    Tar produced by biomass gasification as a route of renewable energy must be removed before the gas can be used. This study was undertaken using toluene as a model tar compound for evaluating its steam reforming conversion with three Ni-based catalysts, Ni/olivine, Ni-Ce/olivine and Ni-Ce-Mg/olivine. Effects of Ce and Mg promoters on the reaction activity and coke deposition were studied. Overall the performance of Ce and Mg promoted Ni/olivine catalysts is better than that of only Ce promoter and Ni/olivine alone. The experimental results indicate that Ni-Ce-Mg/olivine catalysts could improve the resistance to carbon deposition, enhance energy gases yield and resist 10ppm H2S poison at 100mLmin(-1) for up to 400min. Furthermore, the activity of catalysts was related to the steam/carbon (S/C) ratios; at S/C ratio=5, T=790°C, space velocity=782h(-1) and t=2h, the Ni-Ce-Mg/olivine system yielded 89% toluene conversion, 5.6Lh(-1) product gas rate, 62.6mol% H2 content and 10% (mol useful gas mol(-1) toluene) energy yield. Moreover, at low S/C ratio, it had higher reaction activity and better ability to prevent coking. There is a small amount of carbon deposition in the form of amorphous carbon after 7h. Various characterization techniques such as XRD, FTIR and thermogravimetric were performed to investigate the coke deposition of Ni/olivine, Ni-Ce/olivine and Ni-Ce-Mg/olivine. It is suggested that 3% Ni-1% Ce-1% Mg/olivine was the most promising catalyst due to its minimum coke amount and the lower activation energy of coke burning.

  5. 碳化镍钼催化剂的制备及其甲烷干气重整活性%Preparation of a Nickel Molybdenum Carbide Catalyst and Its Activity in the Dry Reforming of Methane

    Institute of Scientific and Technical Information of China (English)

    Taro HIROSE; Yasushi OZAWA; Masatoshi NAGAI

    2011-01-01

    Nickel molybdenum carbide catalysts were prepared and their activities in the CO2 reforming of methane at a low CO2/CH4 reactant ratio were investigated using a microreactor at atmospheric pressure and at 973 K The effect of the catalyst preparation method and the Ni/Mo ratio on the increase in catalyst life and the promotion of catalytic activity were investigated using N2 adsorption, X-ray diffraction,temperature-programmed carburization, temperature-programmed reaction, and a reforming reaction. The 25Ni75Mo catalyst that was carburized at 813 K exhibited the highest hydrogen fonnation ability and gave the least carbon deposition. The incomplete carburization of the Mo oxide species in the catalyst that was carburized at a lower temperature gradually gave a more active carburized species. The NiMoOxCy in the catalyst was more active in hydrogen formation during the dry reforming of methane while β-Mo2C and η-Mo3C2 were less active.

  6. A Novel Study of Methane-Rich Gas Reforming to Syngas and Its Kinetics over Semicoke Catalyst

    Directory of Open Access Journals (Sweden)

    Guojie Zhang

    2014-01-01

    Full Text Available A small-size gasification unit is improved through process optimization to simulate industrial United Gas Improvement Company gasification. It finds that the reaction temperature has important impacts on semicoke catalyzed methane gas mixture. The addition of water vapor can enhance the catalytic activity of reforming, which is due to the fact that addition of water vapor not only removes carbon deposit produced in the reforming and gasification reaction processes, but also participates in gasification reaction with semicoke to generate some active oxygen-containing functional groups. The active oxygen-containing functional groups provide active sites for carbon dioxide reforming of methane, promoting the reforming reaction. It also finds that the addition of different proportions of methane-rich gas can yield synthesis gas with different H2/CO ratio. The kinetics study shows that the semicoke can reduce the activation energy of the reforming reaction and promote the occurrence of the reforming reaction. The kinetics model of methane reforming under the conditions of steam gasification over semicoke is as follows: k-=5.02×103·pCH40.71·pH20.26·exp(−74200/RT.

  7. Highly Active and Stable MgAl2O4 Supported Rh and Ir Catalysts for Methane Steam Reforming: A Combined Experimental and Theoretical Study

    Energy Technology Data Exchange (ETDEWEB)

    Mei, Donghai; Glezakou, Vassiliki Alexandra; Lebarbier, Vanessa MC; Kovarik, Libor; Wan, Haiying; Albrecht, Karl O.; Gerber, Mark A.; Rousseau, Roger J.; Dagle, Robert A.

    2014-07-01

    In this work we present a combined experimental and theoretical investigation of stable MgAl2O4 spinel-supported Rh and Ir catalysts for the steam methane reforming (SMR) reaction. Firstly, catalytic performance for a series of noble metal catalysts supported on MgAl2O4 spinel was evaluated for SMR at 600-850°C. Turnover rate at 850°C follows the order: Pd > Pt > Ir > Rh > Ru > Ni. However, Rh and Ir were found to have the best combination of activity and stability for methane steam reforming in the presence of simulated biomass-derived syngas. It was found that highly dispersed ~2 nm Rh and ~1 nm Ir clusters were formed on the MgAl2O4 spinel support. Scanning Transition Electron Microscopy (STEM) images show that excellent dispersion was maintained even under challenging high temperature conditions (e.g. at 850°C in the presence of steam) while Ir and Rh catalysts supported on Al2O3 were observed to sinter at increased rates under the same conditions. These observations were further confirmed by ab initio molecular dynamics (AIMD) simulations which find that ~1 nm Rh and Ir particles (50-atom cluster) bind strongly to the MgAl2O4 surfaces via a redox process leading to a strong metal-support interaction, thus helping anchor the metal clusters and reduce the tendency to sinter. Density functional theory (DFT) calculations suggest that these supported smaller Rh and Ir particles have a lower work function than larger more bulk-like ones, which enables them to activate both water and methane more effectively than larger particles, yet have a minimal influence on the relative stability of coke precursors. In addition, theoretical mechanistic studies were used to probe the relationship between structure and reactivity. Consistent with the experimental observations, our theoretical modeling results also suggest that the small spinel-supported Ir particle catalyst is more active than the counterpart of Rh catalyst for SMR. This work was financially supported by the

  8. Ni/γ-Al2O3 Catalyst for CO2 Reforming of Benzene as a Model Compound of Biomass Gasification Tar: Promotional Effect of Ultrasonic Treatment on Catalytic Performance

    Science.gov (United States)

    Li, B.; Chen, H. P.; Yang, H. P.; Yang, G. L.; Wang, X. H.; Zhang, S. H.

    This paper aims to understand the promotional effect of ultrasonic treatment on catalytic performance of Ni/γ-Al2O3 catalyst for CO2 reforming of benzene as a model compound of tar derived from biomass gasification, and the catalytic cracking mechanism was also discussed. Firstly, three Ni/γ-Al2O3catalysts were prepared by ultrasonic impregnation as the ultrasonic power variantat0, 120 and 500W, andthephysicochemical property of catalysts were characterized using N2-adsorption, SEM and XRD, etc. Then the catalytic performance of three catalysts for CO2 reforming of benzene wastestedin amicro-reactor.Theoutlet gaswas measured using a Micro-GC. Finally, the coking amount on the catalyst surface was measured by thermogravimetry (TG). The results showed that ultrasonic treatment significanüy modified the pore size distribution of the catalysts especiallyin theporesize range of 10-50nm andalso improved the capability of the coke resistance. It's beneficial to increase the lifetime of the catalyst. Meanwhile, lower ultrasonic power(120W) was more favorableto improve the coke resistance of the catalyst in the power range tested (120 and 500W). The main surface reactions over Ni/γ-Al2O3 catalysts included two steps: Firstly, benzeneadsorbed on the catalyst surface, the metal active sites dehydrogenation took place, and the residual molecule fragments (coke precursor) wouldcondense further which led to coke formation.Then, CO2 reacted with coke precursor and coke for coke elimination. The first step carriedout very quickly, and the second step was the rate-determining step.To reduce the cokedeposition on the catalyst surface, the performance of CO2 adsorption and activation and surface oxygen transmission capacity should be improved further.

  9. The role of metal-support interaction for CO-free hydrogen from low temperature ethanol steam reforming on Rh-Fe catalysts.

    Science.gov (United States)

    Choong, Catherine K S; Chen, Luwei; Du, Yonghua; Schreyer, Martin; Daniel Ong, S W; Poh, Chee Kok; Hong, Liang; Borgna, Armando

    2017-02-08

    Rh-Fe catalysts supported on Ca-Al2O3, MgO and ZrO2 were evaluated in ethanol steam reforming at 623 K and compared to Rh catalysts on the same supports without iron promotion. The metal-support interaction among the three entities, i.e. Rh ↔ Fe2O3 ← support (ZrO2, MgO and Ca-Al2O3) was investigated using H2-chemisorption, TEM, XPS and in situ techniques such as DRIFTS, temperature-resolved XRD and XAS. As compared to the unpromoted Rh catalysts on the same supports, the CO selectivity is depressed in the presence of iron on Rh/MgO and Rh/Ca-Al2O3, the latter being significantly superior. The role of metal-support interaction for CO-free hydrogen generation was unravelled using a combination of techniques. It was found that the reducibility of iron oxide determines the extent of the strong metal support interaction between Rh and Fe2O3 and the reducibility of iron oxide was affected by the support. On Rh-Fe/Ca-Al2O3, a good balance of the interaction between Rh, Fe2O3 and Ca-Al2O3 prevents strong metal support interaction between Rh and Fe2O3 and thus promotes CO elimination via water-gas-shift reaction on Rh-FexOy sites.

  10. Simple cerium-triethanolamine complex: Synthesis, characterization, thermal decomposition and its application to prepare ceria support for platinum catalysts used in methane steam reforming

    Science.gov (United States)

    Wattanathana, Worawat; Nootsuwan, Nollapan; Veranitisagul, Chatchai; Koonsaeng, Nattamon; Laosiripojana, Navadol; Laobuthee, Apirat

    2015-06-01

    Cerium-triethanolamine complex was synthesized by simple complexation method in 1-propanol solvent using cerium(III) chloride as a metal source and triethanolamine as a ligand. The structures of the prepared complex were proposed based on FT-IR, FT-Raman and ESI-MS results as equimolar of triethanolamine and cerium chelated complex having monomeric tricyclic structure with and without chloride anion as another coordinating group known as ceratrane. The complex was used as a precursor for ceria material done by thermal decomposition. XRD result revealed that when calcined at 600 °C for 2 h, the cerium complex was totally turned into pure ceria with cubic fluorite structure. The obtained ceria was then employed to synthesize platinum doped ceria catalysts for methane steam reforming. Various amounts of platinum i.e. 1, 3, 5 and 10 mol percents were introduced on the ceria support by microwave-assisted wetness impregnation using ammonium tetrachloroplatinate(II). The platinum-impregnated ceria powders were subjected to calcination in 10% hydrogen/helium atmosphere at 500 °C for 3 h to reduce platinum(II) to platinum(0). XRD patterns of the catalysts confirmed that the platinum particles doped on the ceria support were in the form of platinum(0). Catalytic activity test showed that the catalytic activities got higher as the amounts of platinum doped increased. Besides, the portions of coke formation on the surface of catalysts were reduced as the amounts of platinum doped increased.

  11. Effects of adding lanthanum to Ni/ZrO{sub 2} catalysts on ethanol steam reforming; Efeito da adicao de lantanio em catalisadores de Ni/ZrO{sub 2} aplicados na reacao de reforma a vapor de etanol

    Energy Technology Data Exchange (ETDEWEB)

    Profeti, Luciene Paula Roberto [Centro de Ciencias Agrarias, Universidade Federal do Espirito Santo, Alegre, ES (Brazil); Habitzheuter, Filipe; Assaf, Elisabete Moreira, E-mail: eassaf@iqsc.usp.br [Instituto de Quimica de Sao Carlos, Universidade de Sao Paulo, Sao Carlos, SP (Brazil)

    2012-07-01

    The catalytic performance of Ni/ZrO{sub 2} catalysts loaded with different lanthanum content for steam reforming of ethanol was investigated. Catalysts were characterized by BET surface area, X-ray diffraction, UV-vis spectroscopy, temperature programmed reduction, and X-ray absorption fine structure techniques. Results showed that lanthanum addition led to an increase in the degree of reduction of both NiO and nickel surface species interacting with the support, due to the higher dispersion effect. The best catalytic performance at 450 deg C was found for the Ni/12LZ catalyst, which exhibited an effluent gaseous mixture with the highest H{sub 2} yield. (author)

  12. Effect of Ni, Fe and Fe-Ni alloy catalysts on the synthesis of metal contained carbon nano-onions and studies of their electrochemical hydrogen storage properties

    Institute of Scientific and Technical Information of China (English)

    Chenguang Zhang; Jiajun Li; Chunsheng Shi; Chunnian He; Enzuo Liu; Naiqin Zhao

    2014-01-01

    Three types of carbon nano-onions (CNOs) including Ni@CNOs, Fe3C@CNOs and Fe0.64Ni0.36@CNOs nanoparticles have been synthesized by catalytic decomposition of methane at 850◦C using nickel, iron and iron-nickel alloy catalysts. Comparative and systematic studies have been carried out on the morphology, structural characteristics and graphitic crystallinity of these CNOs products. Furthermore, the electro-chemical hydrogen storage properties of three types of CNOs have been investigated. Measurements show that the Ni@CNOs have the highest discharge capacity of 387.2 mAh/g, corresponding to a hydrogen storage of 1.42%. This comparison study shows the advantages of each catalyst in the growth of CNOs, enabling the controllable synthesis and tuning the properties of CNOs by mediating different metals and their alloy for using in the fuel cell system.

  13. Structure, activity, and stability of platinum alloys as catalysts for the oxygen reduction reaction

    DEFF Research Database (Denmark)

    Vej-Hansen, Ulrik Grønbjerg

    and dealloying due to kinetic barriers, despite the thermodynamic driving force for dissolution. This is followed by our results on trying to decouple the strain and ligand effects for platinum skin structures, and determining whether there is any correlation between adsorption energy and surface stability...... in these systems. We find that there is such a correlation for some adsorbates, indicating that there exists a limit for the stability of an overlayer for a given adsorption strength. Finally, we introduce our work on platinum alloy nanoparticles, and our attempt to isolate the features which result...... in the increased activity that has been seen experimentally. We show how the platinum-platinum distance at the surface is decreased for a variety of alloy phases in the core, with greater compression of the overlayer for core phases with lattice parameters which are either much smaller or much larger than pure...

  14. State of Ni in catalysts for glycerol hydrogenation and methane steam reforming as studied by X-ray absorption spectroscopy

    Science.gov (United States)

    Tkachenko, O. P.; Kustov, L. M.

    2013-06-01

    X-ray absorption spectroscopy is used to study 1% Ni/Al2O3, 5% Ni/Al2O3, and 5% Ni/TiO2 catalysts for glycerol and methane conversion. The effect of treatment in H2 under microwave irradiation on the reduction of part of the nickel to the metallic state in the titanium oxide-supported catalyst is demonstrated.

  15. Nitrogen-doped graphene/CoNi alloy encased within bamboo-like carbon nanotube hybrids as cathode catalysts in microbial fuel cells

    Science.gov (United States)

    Hou, Yang; Yuan, Heyang; Wen, Zhenhai; Cui, Shumao; Guo, Xiaoru; He, Zhen; Chen, Junhong

    2016-03-01

    Cost-effective catalysts are of key importance to the successful deployment of microbial fuel cells (MFCs) for electricity generation from organic wastes. Herein, a novel catalyst prepared by one-step synthesis strategy is reported. The catalyst features N-doped bamboo-like carbon nanotube (BCNT) in which CoNi-alloy is encapsulated at the end and/or the middle section of the tube with many graphene layers inside inner cavities of BCNT (N-G@CoNi/BCNT). The prepared N-G@CoNi/BCNT exhibits a high oxygen reduction reaction (ORR) activity with an early onset potential of 0.06 V vs. Ag/AgCl and a comparable exchange current density to that of commercial Pt/C. The excellent catalytic activity is further evidenced by a high electron transfer number of 3.63. When being applied in MFCs, the N-G@CoNi/BCNT yields an average current density of 6.7 A m-2, slightly lower than that of Pt/C but with a less mass transfer potential loss. The cost of the N-G@CoNi/BCNT for constructing a 1-m2 cathode electrode is 200 times lower than that of Pt/C. With such a competitive price and excellent electrocatalytic-activity resulting from its unique morphology, CoNi-alloy/nitrogen dopants, considerable specific surface area, and carbon-coated alloy/graphene hybridization, the present catalyst is a promising candidate for ORR catalysts in MFCs for energy recovery from wastes.

  16. Deactivation and Regeneration of Nickel-Based Catalysts for Steam-Methane Reforming%用于甲烷水蒸气重整的镍基催化剂的失活和再生

    Institute of Scientific and Technical Information of China (English)

    Seyed Meysam HASHEMNEJAD; Matin PARVARI

    2011-01-01

    The deactivation of nickel catalysts used in Arak and Razi petrochemical complexes followed by catalyst regeneration was evaluated. The characterization of the different structures was made by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), and carbon & sulfur analyzer. The Ni particle size was estimated from XRD patterns and TEM graphs. The agglomeration of nickel particle and the poison by sulfur components were recognized as the main reasons in deactivation of Arak and Razi catalysts, respectively. The activity of the used catalysts before and after regeneration was measured on methane steam reforming at a CH4:H2O ratio of 1:3 at 850 ℃. The regeneration processes for Arak and Razi samples were performed with CO2 as an oxidative atmosphere and steam as a regenerating agent, respectively. The results show that, (1) no residual sulfur components were on the regenerated Razi catalyst surface without changing the structure of the catalyst and the regenerated catalyst has gained 80% of its catalytic activity, and that (2) the nickel particle size of regenerated Arak specimen decreased remarkably as measured by Debye-Scherrer equation from XRD patterns. TEM images were in agreement with the XRD results and indicated a decrease in nickel particle size of regenerated catalyst. Additionally, in both regenerated catalysts all the coke on the surface of the support was eliminated after regeneration.

  17. Combined high-pressure cell-ultrahigh vacuum system for fast testing of model metal alloy catalysts using scanning mass spectrometry

    DEFF Research Database (Denmark)

    Johansson, Martin; Jørgensen, Jan Hoffmann; Chorkendorff, Ib

    2004-01-01

    An apparatus for fabrication, surface analysis in ultrahigh vacuum, and testing of the catalytic activity of model metal alloy catalysts is described. Arrays of model catalysts are produced by electron-beam deposition of up to four metals simultaneously onto a substrate. The surface analysis...... techniques available are scanning electron microscopy, x-ray photoemission spectroscopy, ion scattering spectroscopy, Auger electron spectroscopy, sputter profiling, and temperature programmed desorption. The catalytic activity of the model catalysts is tested individually by scanning a combined gas delivery...... be studied on a substrate 10 mm in diameter. A high pressure cell with an all-metal sealed ultrahigh vacuum lock is also described as part of the work. ©2004 American Institute of Physics....

  18. A Platinum Monolayer Core-Shell Catalyst with a Ternary Alloy Nanoparticle Core and Enhanced Stability for the Oxygen Reduction Reaction

    Directory of Open Access Journals (Sweden)

    Haoxiong Nan

    2015-01-01

    Full Text Available We synthesize a platinum monolayer core-shell catalyst with a ternary alloy nanoparticle core of Pd, Ir, and Ni. A Pt monolayer is deposited on carbon-supported PdIrNi nanoparticles using an underpotential deposition method, in which a copper monolayer is applied to the ternary nanoparticles; this is followed by the galvanic displacement of Cu with Pt to generate a Pt monolayer on the surface of the core. The core-shell Pd1Ir1Ni2@Pt/C catalyst exhibits excellent oxygen reduction reaction activity, yielding a mass activity significantly higher than that of Pt monolayer catalysts containing PdIr or PdNi nanoparticles as cores and four times higher than that of a commercial Pt/C electrocatalyst. In 0.1 M HClO4, the half-wave potential reaches 0.91 V, about 30 mV higher than that of Pt/C. We verify the structure and composition of the carbon-supported PdIrNi nanoparticles using X-ray powder diffraction, X-ray photoelectron spectroscopy, thermogravimetry, transmission electron microscopy, and energy dispersive X-ray spectrometry, and we perform a stability test that confirms the excellent stability of our core-shell catalyst. We suggest that the porous structure resulting from the dissolution of Ni in the alloy nanoparticles may be the main reason for the catalyst’s enhanced performance.

  19. Formation and Characterization of Pd, Pt and Pd-Pt Alloy Films on Polyimide by Catalyst-Enhanced Chemical Vapor Deposition

    Institute of Scientific and Technical Information of China (English)

    ZHOU Jinlan; CHENG Yinhua; Yousuf Hamadan; YU Kaichao

    2007-01-01

    Platinum, palladium and their alloy films on polyimide were formed by catalyst-enhanced chemical vapor deposition (CVD) in the carrier gas (N2, O2) at 220-300 ℃ under reduced pressure and normal pressure. The deposition of palladium complexes [ Pd((η3-allyl)(hfac) and Pd(hfac)2 ] gives pure palladium film,while the deposition of platinum needs the enhancement of palladium complex by mixing precursor platinum complex Pt(COD)Me2 and palladium complex in the same chamber. The co-deposition of Pd and Pt metals was used for the deposition of alloy films. During the CVD of palladium-platinum alloy, the Pd/Pt atomic ratios vary under different co-deposition conditions. These metal films were characterized by XPS and SEM, and show a good adhesive property.

  20. Recovery of Nickel from Reformer Catalysts of Direct Reduction, Using the Pressurized Dissolving Method in Nitric Acid

    Directory of Open Access Journals (Sweden)

    B. Abrar

    2016-10-01

    Full Text Available In the process of direct reduction of iron pellet and production of sponge iron, NiO/Al2O3 act as a catalyst for the generation of carbon monoxide and hydrogen by vapor and natural gas. As an expensive material used in MIDREX method for steel units, this type of catalyst has major environmental problems after accumulation. The steel industry in Iran hopes to employ the MIDREX technique for the 80 percent of the 50 million tons of steel. Thus, the problem of spent catalysts will become a serious environmental challenge. Through the hydrometallurgy method, the present study investigates a possible solution to the problem of catalyst depot (due to heavy metals such as nickel via nickel recovery, which may increase the possibility of selling or re-using the precious and expensive metal. The present research studied the Nickel recovery from spent catalysts of NiO/Al2O¬3 used in reduction gas reliefs of the production of sponge iron unit. In this study, the parameters of temperature, concentration, time and Rpm were studied using pressurized dissolving method. 100% efficiency was achieved at 140 °C for 120 minutes, nitric acid concentration of 1.5 mm, Rpm of 600 and 40 s/l 40 grams per liter.

  1. Alternative alloys for catalysts and platinum jewelry? New structures in Pt-Hf and Pt-Mo

    Science.gov (United States)

    Gilmartin, Erin; Corbitt, Jacqueline; Hart, Gus

    2009-03-01

    The only known intermetallic structure with an 8:1 stoichiometry is that of Pt8Ti. It is intriguing that an ordered phase would occur at such low concentrations of the minority atom, but this structure occurs in about a dozen binary intermetallic systems. The formation of an ordered phase in an alloy can significantly enhance the performance of the material, particularly the hardness. We have taken a broad look at possible systems where this phase forms. Using first-principles, we calculated the stability of this structure relative to experimentally known phases for more than 80 Pt/Pd binary systems. We find the Pt8Ti structure is a possible ground state in more than 20 cases. Our experimental collaborators have verified our prediction in Pt-Mo and observed order-hardening in Pt-Hf. We discuss the discovery of new ground states that are likely to be verified experimentally and their impact on materials for Pt- and Pd-based catalysts and jewelry.

  2. Effect of Transition Metals (Cu, Co and Fe) on the Autothermal Reforming of Methane over Ni/Ce0.2Zr0.1Al0.7Oδ Catalyst

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The transition metals (Cu, Co, and Fe) were applied to modify Ni/Ce0.2Zr0.1Al0.7Oδ catalyst.The effects of transition metals on the catalytic properties of Ni/Ce0.2Zr0.1Al0.7Oδ autothermal reforming of methane were investigated. The Ni-supported catalysts were characterized by XRD, TPR and XPS.Tests in autothermal reforming of methane to hydrogen showed that the addition of transition metals (Cu and Co) significantly increased the activity of catalyst under the conditions of lower reaction temperature,and Ni/Cu0.05Ce0.2Zr0.1Al0.65Oδ was found to have the highest conversion of CH4 among all catalysts in the operation temperatures ranging from 923 K to 1023 K. TPR, XRD and XPS measurements indicated that the cubic phases of CexZr1-xO2 solid solution were formed in the preparation process of catalysts.Strong interaction was found to exist between NiO and CexZr1-xO2 solid solution. The addition of Cu improved the dispersion of NiO, inhibited the formation of NiAl2O4, and thus significantly promoted the activity of the catalyst Ni/Cu0.05Ce0.2Zr0.1Al0.65Oδ.

  3. Methane reforming With CO2 to syngas over CeO2-promoted Ni/Al2O3-ZrO2 catalysts Prepared Via a direct sol-gel process

    Institute of Scientific and Technical Information of China (English)

    Hansheng Li; Hang Xu; Jinfu Wang

    2011-01-01

    CeO2-promoted Ni/Al2O3-ZrO2 (Ni/Al2O3-ZrO2-CeO2) catalysts were prepared by a direct sol-gel process with citric acid as gelling agent.The catalysts used for the methane reforming with CO2 was studied by infrared spectroscopy (IR), thermal gravimetric analysis (TGA), microscopic analysis, X-ray diffraction (XRD) and temperature-programmed reduction (TPR).The catalytic performance for CO2 reforming of methane to synthesis gas was investigated in a continuous-flow micro-reactor under atmospheric pressure.TGA, IR, XRD and microscopic analysis show that the catalysts prepared by the direct sol-gel process consist of Ni particles with a nanostructure of around 5 nm and an amorphous-phase composite oxide support.There exists a chemical interaction between metallic Ni particles and supports, which makes metallic Ni well dispersed, highly active and stable.The addition of CeO2 effectively improves the dispersion and the stability of Ni particles of the prepared catalysts, and enhances the adsorption of CO2 on the surface of catalysts.The catalytic tests for methane reforming with CO2 to synthesis gas show that the Ni/Al2O3-ZrO2-CeO2 catalysts show excellent activity and stability compared with the Ni/Al2O3 catalyst.The excellent catalytic activity and stability of the Ni/Al2O3-ZrO2-CeO2 are attributed to the highly, uniformly and stably dispersed small metallic Ni particles, the high reducibility of the Ni oxides and the interaction between metallic Ni particles and the composite oxide supports.

  4. Recovery of rare metal compounds from nickel-metal hydride battery waste and their application to CH4 dry reforming catalyst.

    Science.gov (United States)

    Kanamori, Tomohiro; Matsuda, Motohide; Miyake, Michihiro

    2009-09-30

    The recovery of valuable components such as nickel from nickel-metal hydride (Ni-MH) battery waste by chemical processes and their applications to CH(4) dry reforming catalysts were investigated. Three types of compound, identified by XRD analysis as NiO, CeO(2) and LaCoO(3) phases, were successfully separated from the waste by a series of chemical processes at room temperature using aqueous solutions of HCl, NaOH and NH(3), and Ni component of approximately 70% in Ni-MH battery waste was recovered. The separated NiO, CeO(2) and LaCoO(3) showed catalytic activities for CH(4) dry reforming. In particular, the separated NiO easily reduced to Ni(0) at an initial stage, and exhibited excellent catalytic activity in terms of CH(4) conversion and stability. Furthermore, it was found that the resulting Ni from separated NiO exhibited an anomalous catalysis from the comparison with that from regent NiO.

  5. Performance improvement of direct internal reforming solid oxide fuel cell fuelled by H2S-contaminated biogas with paper-structured catalyst technology

    Science.gov (United States)

    Shiratori, Y.; Sakamoto, M.

    2016-11-01

    Direct internal reforming (DIR) operation of a solid oxide fuel cell (SOFC) is a very attractive concept for downsizing and cost reduction of SOFC systems. This study aimed to develop stable operation of a DIR-SOFC fuelled by biogas. The current-voltage (I-V) curves of 2 × 2 cm2 planar SOFCs (anode- and electrolyte-supported cells, ASC and ESC, respectively.) were measured at 800 °C in the direct feed of a simulated biogas mixture (CH4/CO2 = 1), and the flexible structured catalyst material (paper-structured catalyst (PSC)) was applied on the anode material for performance enhancement. By applying a hydrotalcite (HT)-dispersed PSC (HT-PSC), the sulfur tolerance of the SOFC in the DIR operation was remarkably improved. By the effect of the HT-PSC, for both ASC and ESC, a stable cell voltage higher than 800 mV was obtained over 200 h at 0.2 A cm-2 in the direct feed of simulated biogas under 5 ppm H2S poisoning.

  6. Session 4: Combine reforming of methane over LaCo{sub 1-x}Ni{sub x}O{sub 3} perovskites as catalysts precursors

    Energy Technology Data Exchange (ETDEWEB)

    Goldwasser, M.R.; Lugo, M.L.; Rivas, M.E.; Pietri, E.; Perez-Zurita, M.J.; Cubeiro, M.L. [Centro de Catalisis, Petroleo y Petroquimica, Escuela de Quimica, Fac. Ciencias, UCV, Apartado 47102, Los Chaguaramos, Caracas (Venezuela); Griboval-Constant, A.; Leclercq, G. [Universite des Sciences ET Technologies de Lille, Lab. de Catalyse Heterogene et Homogene, 59 - Villeneuve D' Ascq (France)

    2004-07-01

    The effect of the partial and total substitution of the nickel by cobalt in a LaNiO{sub 3} perovskite as catalyst precursors in the combine reforming of methane with CO{sub 2} and O{sub 2} for the production of syngas was studied. The solids were synthesized by the sol gel method and characterized by IR, BET surface area, XRD, TPR, EDX and in situ XRD under the condition of fresh, reduced and used samples. The results showed that through this synthesis it is possible to obtain highly crystalline, homogeneous and pure solids, with well-defined structures. It was observed that by reduction of the perovskites, the metals (Co, Ni) are in a highly disperse state on a matrix compose of the La{sub 2}O{sub 3}. The stabilization of nickel by the presence of Co was evidenced, decreasing deactivation by avoiding the sintering of metals by coke formation on the surface of the catalysts. (authors)

  7. Influence of supports on catalytic behavior of nickel catalysts in carbon dioxide reforming of toluene as a model compound of tar from biomass gasification.

    Science.gov (United States)

    Kong, Meng; Fei, Jinhua; Wang, Shuai; Lu, Wen; Zheng, Xiaoming

    2011-01-01

    A series of supported Ni catalysts including Ni/MgO, Ni/γ-Al2O3, Ni/α-Al2O3, Ni/SiO2 and Ni/ZrO2 was tested in CO2 reforming of toluene as a model compound of tar from biomass gasification in a fluidized bed reactor, and characterized by the means of temperature programmed reduction with hydrogen (H2-TPR), XRD, TEM and temperature programmed oxidation (TPO). Combining the characterization results with the performance tests, the activity of catalyst greatly depended on Ni particles size, and the stability was affected by the coke composition. Both of them (Ni particle size and coke composition) were closely related to the interaction between nickel and support which would determine the chemical environment where Ni inhabited. The best catalytic performance was observed on Ni/MgO due to the strong interaction between NiO and MgO via the formation of Ni-Mg-O solid solution, and the highest dispersion of Ni particle in the basic environment.

  8. Stability and activity of carbon nanofiber-supported catalysts in the aqueous phase reforming of ethylene glycol

    NARCIS (Netherlands)

    Haasterecht, van T.; Ludding, C.C.I.; Jong, de K.P.; Bitter, J.H.

    2013-01-01

    Nickel, cobalt, copper and platinum nanoparticles supported on carbon nano-fibers were evaluated with respect to their stability, catalytic activity and selectivity in the aqueous phase reforming of ethylene glycol (230 ¿, autogenous pressure, batch reactor). The initial surface-specific activities

  9. Ru decorated carbon nanotubes - a promising catalyst for reforming bio-based acetic acid in the aqueous phase

    NARCIS (Netherlands)

    Vlieger, de D.J.M.; Lefferts, L.; Seshan, K.

    2014-01-01

    Catalytic reforming of biomass derived waste streams in the aqueous phase is a promising process for the production of sustainable hydrogen. Acetic acid will be a major component (up to 20 wt%) in many anticipated gasification feed streams (e.g. the aqueous fraction of pyrolysis oil). Conventional s

  10. Stability and activity of carbon nanofiber-supported catalysts in the aqueous phase reforming of ethylene glycol

    NARCIS (Netherlands)

    van Haasterecht, T.|info:eu-repo/dai/nl/328206458; Ludding, C.C.I.; de Jong, K.P.|info:eu-repo/dai/nl/06885580X; Bitter, J.H.|info:eu-repo/dai/nl/160581435

    2013-01-01

    Nickel, cobalt, copper and platinum nanoparticles supported on carbon nano-fibers were evaluated with respect to their stability, catalytic activity and selectivity in the aqueous phase reforming of ethylene glycol (230 ◦C, autogenous pressure, batch reactor). The initial surface-specific activities

  11. Stability and activity of carbon nanofiber-supported catalysts in the aqueous phase reforming of ethylene glycol

    NARCIS (Netherlands)

    Haasterecht, van T.; Ludding, C.C.I.; Jong, de K.P.; Bitter, J.H.

    2013-01-01

    Nickel, cobalt, copper and platinum nanoparticles supported on carbon nano-fibers were evaluated with respect to their stability, catalytic activity and selectivity in the aqueous phase reforming of ethylene glycol (230 ¿, autogenous pressure, batch reactor). The initial surface-specific activities

  12. Ru decorated carbon nanotubes - a promising catalyst for reforming bio-based acetic acid in the aqueous phase

    NARCIS (Netherlands)

    de Vlieger, Dennis; Lefferts, Leonardus; Seshan, Kulathuiyer

    2014-01-01

    Catalytic reforming of biomass derived waste streams in the aqueous phase is a promising process for the production of sustainable hydrogen. Acetic acid will be a major component (up to 20 wt%) in many anticipated gasification feed streams (e.g. the aqueous fraction of pyrolysis oil). Conventional

  13. Stability and activity of carbon nanofiber-supported catalysts in the aqueous phase reforming of ethylene glycol

    NARCIS (Netherlands)

    van Haasterecht, T.; Ludding, C.C.I.; de Jong, K.P.; Bitter, J.H.

    2013-01-01

    Nickel, cobalt, copper and platinum nanoparticles supported on carbon nano-fibers were evaluated with respect to their stability, catalytic activity and selectivity in the aqueous phase reforming of ethylene glycol (230 ◦C, autogenous pressure, batch reactor). The initial surface-specific activities

  14. CuAu–ZnO–graphene nanocomposite: A novel graphene-based bimetallic alloy-semiconductor catalyst with its enhanced photocatalytic degradation performance

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Hong [College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000 (China); Ye, Xiaoliang [College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000 (China); College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005 (China); Duan, Kaiyue; Xue, Muyin; Du, Yongling; Ye, Weichun [College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000 (China); Wang, Chunming, E-mail: wangcm@lzu.edu.cn [College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000 (China)

    2015-07-05

    Graphical abstract: In this work, we have successfully synthesized a novel graphene-based bimetallic alloy-semiconductor catalyst: CuAu–ZnO–Gr nanocomposite, and which behaved an enhanced photocatalytic activity. - Highlights: • A bimetallic alloy-based catalyst: CuAu–ZnO–Gr is synthesized. • CuAu–ZnO–Gr behaves an enhanced photocatalytic activity. • The detailed explanation of photocatalytic mechanism of CuAu–ZnO–Gr. - Abstract: The bimetallic alloy CuAu nanoparticles (NPs) can produce more photogenerated electrons when compared with single metal Au NPs. Moreover, graphene (Gr) sheets can help the charge separation and slow down the recombination of the electron hole pairs of ZnO. Hence, a novel graphene-based bimetallic alloy-semiconductor catalyst: CuAu–ZnO–Gr nanocomposite is synthesized. Due to the synergistic effect among CuAu NPs, ZnO nanopyramids, and Gr sheets, CuAu–ZnO–Gr behaves an enhanced photocatalytic activity for the photocatalytic degradation of synthetic colorants methyl orange (MO), methylene blue (MB), indigotin (IN), sunset yellow (SY), and tartrazine (TT) under the simulated sunlight irradiation. Furthermore, the apparent rate constants (k{sub app}) of MO, MB, IN, SY, and TT degradation are estimated respectively. In addition, the as-prepared CuAu–ZnO–Gr nanocomposite is characterized by X-ray diffraction, UV–vis spectrum, transmission electron microscopy, energy dispersive X-ray analysis (EDX), and EDX mapping. As a result of the facile synthesis route and the enhanced photocatalytic activity, this new material CuAu–ZnO–Gr can be a promising photocatalyst for the degradation of dyes.

  15. Advanced Catalysis Technologies: Lanthanum Cerium Manganese Hexaaluminate Combustion Catalysts for Flat Plate Reactor for Compact Steam Reformers

    Science.gov (United States)

    2008-12-01

    E. Pocoroba, E.M. Johansson, S.G. Jaras, ”Aging Of Palladium, Platinum And Manganese-Based Combustion Catalysts For Biogas Applications,” Catalysis...M.J. Binder, “JP-8 Catalytic Cracking For Compact Fuel Processors,” Journal of Power Sources 129 (2004) 81-89. 12. P-O.F. Andersson, M

  16. Simultaneous Production of CH4 and H2 from Photocatalytic Reforming of Glucose Aqueous Solution on Sulfated Pd-TiO2 Catalysts

    Directory of Open Access Journals (Sweden)

    Vaiano Vincenzo

    2015-09-01

    Full Text Available In this work, the simultaneous production of CH4 and H2 from photocatalytic reforming of glucose aqueous solution on Pd-TiO2 catalysts under UV light irradiation by Light-Emitting Diodes (LED was investigated. The Pd-TiO2 catalysts were prepared by the photodeposition method. The Pd content was in the range 0.5-2 wt% and a photodeposition time in the range 15-120 min was used. Pd-TiO2 powders were extensively characterized by X-Ray Diffraction (XRD, SBET, X-Ray Fluorescence spectrometry (XRF, UV-Vis Diffuse Reflectance Spectra (UV-Vis DRS, TEM and X-Ray Photoelectron spectroscopy (XPS. It was found that the lower Pd loading (0.5 wt% and 120 min of photodeposition time allowed us to obtain homogeneously distributed metal nanoparticles of small size; it was also observed that the increase in the metal loading and deposition time led to increasing the Pd0 species effectively deposited on the sulfated TiO2 surface. Particle size and the oxidation state of the palladium were the main factors influencing the photocatalytic activity and selectivity. The presence of palladium on the sulfated titania surface enhanced the H2 and CH4 production. In fact, on the catalyst with 0.5 wt% Pd loading and 120 min of photodeposition time, H2 production of about 26 μmol was obtained after 3 h of irradiation time, higher than that obtained with titania without Pd (about 8.5 μmol. The same result was obtained for the methane production. The initial pH of the solution strongly affected the selectivity of the system. In more acidic conditions, the production of H2 was enhanced, while the CH4 formation was higher under alkaline conditions.

  17. Effect of the preparation method of support on the aqueous phase reforming of ethylene glycol over 2 wt% Pt/Ce0.15Zr0.85O2 catalysts.

    Science.gov (United States)

    Kim, Jung-Hyun; Jeong, Kwang-Eun; Kim, Tae-Wan; Chae, Ho-Jeong; Jeong, Soon-Yong; Kim, Chul-Ung; Lee, Kwan-Young

    2013-08-01

    The effect of catalyst support on the aqueous phase reforming of ethylene glycol over supported 2 wt% Pt/Ce0.15Zr0.85O2 catalysts have been investigated. Various types of Ce0.15Zr0.85O2 mixed oxides were prepared by hydrothermal precipitation (CZH), modified precipitation (CZM), co-precipitation (CZC), sol-gel (CZS) methods, respectively. Catalysts were characterized by XRD, N2 sorption analysis, and cyclohexane dehydration for relative metal dispersion. The support effect on the activity of 2 wt% Pt/Ce0.15Zr0.85O2 catalysts with different preparation method was given as follows: CZH production rate and hydrogen yield increased in proportion to the reaction temperature and corresponding system pressure, whereas WHSV did not affect.

  18. Design of heterogeneous catalysts

    DEFF Research Database (Denmark)

    Frey, Anne Mette

    was inspired by a computational screening, suggesting that alloys such as Ni-Fe, Co-Ni, and Co-Fe should show superior activity to the industrially used nickel catalyst. Especially the Ni-Fe system was considered to be interesting, since such alloy catalysts should be both more active and cheaper than the Ni...... well, and the best catalyst prepared had a C5+ yield almost a factor of two higher than a standard air calcined Co catalyst. In the NH3-SCR reaction it is desirable to develop an active and stable catalyst for NOx removal in automotive applications, since the traditionally used vanadium-based catalyst...... pose an environmental risk. The focus was put on iron-containing zeolite catalysts, since these recently have shown great potential as catalysts for the process. A number of different zeolites were compared. BEA was found to be the most active, thus focus was put on this material. Different preparation...

  19. Steam reforming of cyclic model compounds of bio-oil over Ni-based catalysts: Product distribution and carbon formation

    DEFF Research Database (Denmark)

    Trane-Restrup, Rasmus; Jensen, Anker Degn

    2015-01-01

    Steam reforming (SR) and oxidative steam reforming (OSR) of furfural, 2-methylfuran, and guaiacol have been investigated in the temperature range 400-800°C at a steam to carbon (S/C)-ratio of 5 and oxygen to carbon (O/C)-ratio of 0.2-1.4 over Ni/CeO2-K/MgAl2O4. Carbon oxides and H2 were the major...... products in the SR of 2-methylfuran and furfural, while the by-products were methane, ethanol, 2-propanol, and acetone. Temperatures of 500°C or above were needed to minimize the formation of by-products in the SR of 2-methylfuran and furfural. Phenolics, like benzenediols and phenol, were produced in high...

  20. Surface Reaction Kinetics of Steam- and CO2-Reforming as Well as Oxidation of Methane over Nickel-Based Catalysts

    OpenAIRE

    Karla Herrera Delgado; Lubow Maier; Steffen Tischer; Alexander Zellner; Henning Stotz; Olaf Deutschmann

    2015-01-01

    An experimental and kinetic modeling study on the Ni-catalyzed conversion of methane under oxidative and reforming conditions is presented. The numerical model is based on a surface reaction mechanism consisting of 52 elementary-step like reactions with 14 surface and six gas-phase species. Reactions for the conversion of methane with oxygen, steam, and CO2 as well as methanation, water-gas shift reaction and carbon formation via Boudouard reaction are included. The mechanism is implemented i...

  1. Production of renewable hydrogen from aqueous-phase reforming of glycerol overPt catalysts supported on different oxides

    OpenAIRE

    Menezes, André O; Rodrigues, Michelly T.; Fraga, Marco André; Zimmaro, Adriana

    2010-01-01

    Aqueous-phase reforming of oxygenated hydrocarbons for hydrogen production presents several advantages as feed molecules can be easily found in a wide range of biomass, there is no need for its vaporization and the process allows thorough exploitation of the environmental benefits of using hydrogen as an energy carrier. The use of glycerol in particular is motivated due to its availability as a consequence of increasing biodiesel production worldwide. In this contribution, the performance ...

  2. Hydrodeoxygenation of phenol over Pd catalysts by in-situ generated hydrogen from aqueous reforming of formic acid

    DEFF Research Database (Denmark)

    Zeng, Ying; Wang, Ze; Lin, Weigang

    2016-01-01

    Hydrodeoxygenation of phenol, as model compound of bio-oil, was investigated over Pd catalysts, using formic acid as a hydrogen donor. The order of activity for deoxygenation of phenol with Pd catalysts was found to be: Pd/SiO2 > Pd/MCM-41 > Pd/CA > Pd/Al2O3 > Pd/HY approximate to Pd/ZrO2 ≈ Pd....../CW > Pd/HSAPO-34 > Pd/HZSM-5. The good performance of Pd/SiO2 is owing to its proper pore structure and large specific surface area. The high level of Bronsted acid sites in SiO2 also favors the deoxygenation of phenol. (C) 2016 Elsevier B.V. All rights reserved....

  3. Hydrogen Production from Glycerol Steam Reforming over Monolithic Catalyst%整体式催化剂上甘油水蒸气重整制氢

    Institute of Scientific and Technical Information of China (English)

    汪丛伟; 于乃超; 阴秀丽; 吴创之

    2014-01-01

    The effect of coating composition and its proportion on the physicochemical properties of monolithic cata-lyst and its catalytic performance in the glycerol steam reforming reaction was investigated. By examining the influ-ence of molar ratio of Ce to Zr,as well as adding La,on catalyst activity,the optimal condition was determined to be the mole ratio of Ce-Zr-La being 1∶1∶1. The monolithic catalyst activities were obviously improved. Underthe condition of glycerin concentration of 10%,space velocity of 3.07,h-1,glycerin can convert completely into gas product within the temperature range;whilst the hydrogen selectivity increased gradually,then leveled off,with a maximum of 90.85%. With the increase of the space velocity and concentration of glycerol,the hydrogen selectivity and the gas phase conversion of monolithic catalyst decreased,but its catalytic performance can still remaingood enough for application.%为改善甘油重整制氢反应在转化率、氢产率以及抑制积碳方面都与热力学平衡存在较大差距的问题,设计开发了整体式重整催化剂.考察了涂层组分、比例对整体式催化剂理化特性及其在甘油水蒸气重整制氢反应中催化性能的影响.通过考察Ce-Zr物质的量比及La的添加对催化剂活性的影响,确定了Ce-Zr-La物质的量比为1∶1∶1为最优条件.整体式催化剂的活性得到明显改善,在甘油质量分数为10%,空速为3.07,h-1时,在温度考察范围内甘油完全转化为气相产物,氢气选择性递增,并趋于平稳,最高可达90.85%;随着空速增大,甘油质量分数的增加,氢气选择性减小,甘油气相转化率降低,但仍可保持较好的转化效果.

  4. Carbon Materials as Catalysts for Decomposition and CO2 Reforming of Methane: A Review%用于甲烷分解和甲烷二氧化炭重整的碳材料催化剂研究进展

    Institute of Scientific and Technical Information of China (English)

    Beatriz FIDALGO; J.(A)ngel MEN(E)NDEZ

    2011-01-01

    The decomposition and CO2 reforming of methane, respectively, are promising altematives to industrial steam methane reforming. In recent years, research has been focused on the development of catalysts that can operate without getting deactivated by carbon deposition, where, in particular, carbon catalysts have shown positive results. In this work,the role of carbon materials in heterogeneous catalysis is assessed and publications on methane decomposition and CO2 reforming of methane over carbon materials are reviewed. The influence of textural properties (BET surface area and micropore volume, etc.) and oxygen surface groups on the catalytic activity of carbon materials are discussed. In addition. this review examines how activated carbon and carbon black catalysts. which are the most commonly used carbon catalysts, are deactivated. Characteristics of the carbon deposits from methane are discussed and the influence of the reactivity to CO2 of fresh carbon and carbonaceous deposits for high and steady conversion during CO2 reforming of CH4 are also considered.

  5. Oxygen reduction activity of Pt and Pt Co-alloy catalysts: A comparison between kinetic measurements and polymer electrolyte fuel cell experiments

    Energy Technology Data Exchange (ETDEWEB)

    Paulus, U.A.; Draschil, C.; Schmidt, T.J. [PSI and Lawrence Berkeley National Lab (United States); Stamenkovic, V. [Lawrence Berkeley National Lab (United States); Markovic, N.M. [Lawrence Berkeley National Lab (United States); Ross, P.N. [Lawrence Berkeley National Lab (United States); Scherer, G.G.

    2002-03-01

    The oxygen reduction reaction (orr) has been studied on various carbon supported Pt Co alloys in comparison to carbon supported platinum in perchloric acid. The applied thin film rotating ring-disk electrode (rrde) technique allows both the investigation of the orr and their kinetic analysis and in parallel the detection and quantification of the amount of peroxide produced during the orr. Polymer Electrolyte Fuel cell (PEFC) experiments using commercially available gas diffusion electrodes (gdes) with Pt/C and Pt Co/C respectively as active layers were carried out to investigate the above characterized catalysts under real PEFC conditions. (author)

  6. Nickel catalyst supported on magnesium and zinc aluminates (MgAl{sub 2}O{sub 4} and ZnAl{sub 2}O{sub 4}) spinels for dry reforming of methane

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, L.C.B. de; Melo, D.M. de A.; Melo, M.A. de F.; Barros, J.M. de F.; Braga, R.M.; Costa, C. de C.; Rodrigues, G., E-mail: ieda.garcia@pq.cnpq.br [Universidade Federal da Paraiba (LACOM/UFPB), Joao Pessoa, PB (Brazil). Dept. de Quimica

    2017-01-15

    Materials such as MgAl{sub 2}O{sub 4} and ZnAl{sub 2}O{sub 4} assessed in the reaction of dry reforming of methane to produce syngas were synthesized by microwave-assisted combustion method using urea as fuel. Samples of synthesized oxides were calcined at 800 °C for 2 h and impregnated with 5% nickel. The impregnated samples were calcined at 850 °C for 4 h to obtain the desired phases. The results of the catalytic tests showed that the catalysts are active for the reaction of dry reforming of methane, and the catalyst that showed the best performance for methane conversion was 5% Ni/MgAl{sub 2}O{sub 4} calcined at 850 °C/4 h. (author)

  7. Computational Investigation of the Thermochemistry and Kinetics of Steam Methane Reforming Over a Multi-Faceted Nickel Catalyst

    KAUST Repository

    Blaylock, D. Wayne

    2011-08-20

    A microkinetic model of steam methane reforming over a multi-faceted nickel surface using planewave, periodic boundary condition density functional theory is presented. The multi-faceted model consists of a Ni(111) surface, a Ni(100) surface, and nickel step edge sites that are modeled as a Ni(211) surface. Flux and sensitivity analysis are combined to gain an increased understanding of the important reactions, intermediates, and surface facets in SMR. Statistical thermodynamics are applied to allow for the investigation of SMR under industrially-relevant conditions (e.g., temperatures in excess of 500 °C and pressures in excess of 1 bar). The most important surface reactions are found to occur at the under-coordinated step edge sites modeled using the Ni(211) surface as well as on the Ni(100) surface. The primary reforming pathway is predicted to be through C*+ O*→ CO*at high temperatures; however, hydrogen-mediated reactions such as C*+ OH*→ COH*and C.H.*+ O*→ CHO*are predicted to become more important at low temperatures. The rate-limiting reactions are predicted to be dissociative chemisorption of methane in addition to the aforementioned C-O addition reactions. © 2011 Springer Science+Business Media, LLC.

  8. Steam Reforming of Bio-Ethanol to Produce Hydrogen over Co/CeO2 Catalysts Derived from Ce1−xCoxO2−y Precursors

    Directory of Open Access Journals (Sweden)

    Yanyong Liu

    2016-02-01

    Full Text Available A series of Ce1−xCoxO2−y precursors were prepared by homogeneous precipitation using urea as a precipitant. The Co/CeO2 catalysts obtained from the Ce1−xCoxO2−y precursors were used for the steam reforming of ethanol to produce hydrogen. Co ions could enter the CeO2 lattices to form Ce1−xCoxO2−y mixed oxides at x ≤ 0.2 using the homogeneous precipitation (hp method. CeO2 was an excellent support for Co metal in the steam reforming of ethanol because a strong interaction between support and metal (SISM exists in the Co/CeO2 catalysts. Because Co/CeO2 (hp prepared by homogeneous precipitation possessed a high BET surface area and small Co metal particles, Co/CeO2 (hp showed a higher ethanol conversion than the Co/CeO2 catalysts prepared using the co-precipitation (cp method and the impregnation (im method. The selectivity of CO2 over Co/CeO2 (hp increased with increasing reaction temperature at from 573 to 673 K, and decreased with increasing reaction temperature above 673 K due to the increase of CO formation. The carbonaceous deposits formed on the catalyst surface during the reaction caused a slow deactivation in the steam reforming of ethanol over Co/CeO2 (hp. The catalytic activity of the used catalysts could be regenerated by an oxidation-reduction treatment, calcined in air at 723 K and then reduced by H2 at 673 K.

  9. 镍基整体式催化剂重整净化生物制粗燃气性能的研究%Reforming of Biomass Raw Fuel Gas over Monolithic Catalyst

    Institute of Scientific and Technical Information of China (English)

    王晨光; 王铁军; 常杰; 吕鹏梅

    2007-01-01

    The performance of the Ni monolithic catalyst for dry reforming and partial oxidation reforming(POR) of biomass fuel gas were studied at 750 ℃ during 108 hours with naphthalene as tar model compound. The catalyst shows good performance in both dry reforming and POR. Tar was completely converted to permanent gases and lighter hydrocarbon compounds. The catalyst kept its activity during the lifetime test.%以萘为焦油模型化合物,考察了镍基整体式催化剂上生物质粗燃气干重整和临氧重整的性能.镍基重整催化剂表现出良好的催化重整活性,焦油全部转化为H2、CO及微量轻质组分.在750 ℃下连续反应108 h,未检测到反应器压降变化和CH4与焦油转化率下降,整体式催化剂表现出较好的活性和稳定性.

  10. Effect of Partial Substitution of Ni by Cu in LaNiO3 Perovskite Catalyst for Dry Methane Reforming

    Institute of Scientific and Technical Information of China (English)

    G.R.MORADI; F.KHOSRAVIAN; M.RAHMANZADEH

    2012-01-01

    A series of ternary perovskite type oxides LaNi1-xCuxO3 (x =0.2,0.4,0.6,0.8,and 1.0) were synthesized via the sol-gel method in propionic acid.Partial substitution of Ni by Cu showed higher activities and selectivities towards syngas products.LaNi0.8Cu0.2O3 was the most active toward the CH4 and CO2 conversions,and was selective for syngas products.Temperature-programmed reduction results showed that the addition of Cu facilitates the reduction of Ni3+ to Ni0,which is the main reason for the higher performance of this catalyst.

  11. Ethanol steam reforming over Rh/Ce{sub x}Zr{sub 1-x}O{sub 2} catalysts. Impact of the CO-CO{sub 2}-CH{sub 4} interconversion reactions on the H{sub 2} production

    Energy Technology Data Exchange (ETDEWEB)

    Birot, Anne; Epron, Florence; Duprez, Daniel [Laboratoire de Catalyse en Chimie Organique (LACCO), UMR 6503 CNRS and University of Poitiers, 40 Avenue du Recteur Pineau, 86022 Poitiers Cedex (France); Descorme, Claude [IRCELYON, UMR 5256 CNRS/Universite Claude Bernard Lyon 1, 2 Avenue Albert Einstein, 69626 Villeurbanne Cedex (France)

    2008-02-21

    Ce{sub x}Zr{sub 1-x}O{sub 2} mixed oxide-supported 1 wt.% Rh catalysts were prepared by wet impregnation using Rh nitrate as a precursor and calcined at 900 C. They were characterized by BET surface area, XRD, CO{sub 2} chemisorption and H{sub 2} chemisorption at -85 C and tested in the ethanol steam reforming at 600 C under atmospheric pressure, with water to ethanol molar ratio equal to 4, without carrier gas. The best performances, i.e. the highest hydrogen yield and the lowest coke deposition, were obtained over Rh/Ce{sub 0.5}Zr{sub 0.5}O{sub 2}, i.e. 3.63 mol H{sub 2}/mol{sub ethanol}. This catalyst was subsequently evaluated under various reaction conditions. Whatever the temperature and the water to ethanol ratio, the ethanol steam reforming yielded a large amount of methane, which tends to reduce the H{sub 2} production. To elucidate the origin of the methane production, CO/CO{sub 2}/CH{sub 4} interconversion reactions were studied. It was shown that such catalyst favours the formation of methane via CO hydrogenation. The direct hydrogenation of CO{sub 2} was not observed. In parallel, the catalyst was active in the reverse water gas shift (RWGS) reaction between CO{sub 2} and H{sub 2}, leading CO and H{sub 2}O. (author)

  12. Catalisadores Ni/Al2O3 promovidos com molibdênio para a reação de reforma a vapor de metano Mo-Ni/AL2O3 catalysts for the methane steam reforming reaction

    Directory of Open Access Journals (Sweden)

    Silvia Sálua Maluf

    2003-03-01

    Full Text Available Mo-promoted Ni/Al2O3 catalysts for the methane steam reforming reaction were studied in this work. The Ni/Al2O3 catalysts were prepared by precipitation and molibdenum was added by impregnation up to 2%wt. The solids were tested using a micro-reactor under two H2Ov/C conditions and were characterized by ICP-OES, XRD, N2 adsoption, H2 chemisorption and TPR. NiO and NiAl2O4 phases were observed and the metallic area decreased with the increase of the Mo content. From the catalytic tests high stability was verified for H2Ov/C=4.0. On the other hand, only the catalyst containing 0,05% Mo stayed stable during 30 hours of the test at H2Ov/C=2.0.

  13. Combustion synthesized copper-ion substituted FeAl2O4 (Cu0.1Fe0.9Al2O4): A superior catalyst for methanol steam reforming compared to its impregnated analogue

    Science.gov (United States)

    Maiti, Sayantani; Llorca, Jordi; Dominguez, Montserrat; Colussi, Sara; Trovarelli, Alessandro; Priolkar, Kaustubh R.; Aquilanti, Giuliana; Gayen, Arup

    2016-02-01

    A series of copper ion substituted MAl2O4 (M = Mg, Mn, Fe and Zn) spinels is prepared by a single step solution combustion synthesis (SCS) and tested for methanol steam reforming (MSR). The copper ion substituted Cu0.1Fe0.9Al2O4 appears to be the most active, showing ∼98% methanol conversion at 300 °C with ∼5% CO selectivity at GHSV = 30,000 h-1 and H2O:CH3OH = 1.1. The analogous impregnated catalyst, CuO (10 at%)/FeAl2O4, is found to be much less active. These materials are characterized by XRD, H2-TPR, BET, HRTEM, XPS and XANES analyses. Spinel phase formation is highly facilitated upon Cu-ion substitution and Cu loading beyond 10 at% leads to the formation of CuO as an additional phase. The ionic substitution of copper in FeAl2O4 leads to the highly crystalline SCS catalyst containing Cu2+ ion sites that are shown to be more active than the dispersed CuO nano-crystallites on the FeAl2O4 impregnated catalyst, despite its lower surface area. The as prepared SCS catalyst contains also a portion of copper as Cu1+ that increases when subjected to reforming atmosphere. The MSR activity of the SCS catalyst decreases with time-on-stream due to the sintering of catalyst crystallites as established from XPS and HRTEM analyses.

  14. Search for new catalysts from a fundamental basis

    Energy Technology Data Exchange (ETDEWEB)

    Andersen, M.; Lytken, O.; Engbaek, J.; Nielsen, G.; Schumacher, N.; Johansson, M.; Chorkendorff, I. [Interdisciplinary Research Center for Catalysis (ICAT), Department of Physics and Department of Chemical Engineering, Building 312, Technical University of Denmark (DTU), DK-2800 Kongens Lyngby (Denmark)

    2005-02-15

    In this overview, we present some of our more fundamental approaches for making new and/or improved catalysts. First, the effect of mono atomic steps is discussed both in relation to the mechanism of the ammonia synthesis, and in terms of relevance for other reactions, such as the steam reforming and methanization processes. The possibility for utilizing steps to improve selectivity is also discussed. It is shown how micro kinetic modelling can be used to predict how the catalyst for the WGS reaction could be improved. Furthermore, an experimental technique is demonstrated, where alloys consisting of up to four metals can be tested under realistic conditions without loosing the ability to study the catalysts with surface science techniques both prior to and after they have been subjected to reaction conditions. Finally, the importance of in situ measurements will be demonstrated for some preliminary investigations of systems of relevance to fuel cell technology.

  15. A new application of photocatalysts: synthesis of nano-sized metal and alloy catalysts by a photo-assisted deposition method.

    Science.gov (United States)

    Mori, Kohsuke; Araki, Takashi; Takasaki, Tomoya; Shironita, Sayoko; Yamashita, Hiromi

    2009-05-01

    Supported Pd catalysts were synthesized using various semiconductor materials by a photo-assisted deposition method under UV-light irradiation. The Pd precursor was deposited and partially reduced by the direct interaction with the photo-excited state of the semiconductor materials, and subsequently transformed into metal particles by H(2) reduction. CO adsorption and Pd K-edge XAFS measurements demonstrated that the mean diameter of the deposited Pd particles can be controlled by the type of employed semiconductor materials. The catalytic activities in the direct synthesis of hydrogen peroxide (H(2)O(2)) using H(2) and O(2) gases under atmospheric pressure were strongly dependent on the type of supports. Here, the use of TiO(2) comprising a mixed phase of anatase and rutile was the most efficient based on the amount of Pd. The photo-assisted deposition also provides a simple and straightforward method to synthesize PdAu alloy nanoparticles. For the structural model of PdAu nanoparticles, we suggest that most of the Au atoms are preferentially located in the core region, whereas the Pd atoms are preferentially located in the shell region. The PdAu/TiO(2) catalysts prepared by the photo-assisted deposition method were shown to perform significantly better than the pure Pd/TiO(2) catalysts.

  16. Alloy

    Science.gov (United States)

    Cabeza, Sandra; Garcés, Gerardo; Pérez, Pablo; Adeva, Paloma

    2014-07-01

    The Mg98.5Gd1Zn0.5 alloy produced by a powder metallurgy route was studied and compared with the same alloy produced by extrusion of ingots. Atomized powders were cold compacted and extruded at 623 K and 673 K (350 °C and 400 °C). The microstructure of extruded materials was characterized by α-Mg grains, and Mg3Gd and 14H-LPSO particles located at grain boundaries. Grain size decreased from 6.8 μm in the extruded ingot, down to 1.6 μm for powders extruded at 623 K (350 °C). Grain refinement resulted in an increase in mechanical properties at room and high temperatures. Moreover, at high temperatures the PM alloy showed superplasticity at high strain rates, with elongations to failure up to 700 pct.

  17. Hydrogen production by aqueous phase reforming of light oxygenated hydrocarbons

    Science.gov (United States)

    Shabaker, John William

    Aqueous phase reforming (APR) of renewable oxygenated hydrocarbons (e.g., methanol, ethylene glycol, glycerol, sorbitol, glucose) is a promising new technology for the catalytic production of high-purity hydrogen for fuel cells and chemical processing. Supported Pt catalysts are effective catalysts for stable and rapid H2 production at temperatures near 500 K (H 2 turnover frequencies near 10 min-1). Inexpensive Raney Ni-based catalysts have been developed using a combination of fundamental and high-throughput studies that have similar catalytic properties as Pt-based materials. Promotion of Raney Ni with Sn by controlled surface reaction of organometallic tin compounds is necessary to control formation of thermodynamically-favorable alkane byproducts. Detailed characterization by Mossbauer spectroscopy, electron microscopy, adsorption studies, and x-ray photoelectron spectroscopy (XPS/ESCA) has shown that NiSn alloys are formed during heat treatment, and may be responsible for enhanced stability and selectivity for hydrogen production. Detailed kinetic studies led to the development of a kinetic mechanism for the APR reaction on Pt and NiSn catalysts, in which the oxygenate decomposes through C--H and O--H cleavage, followed by C--C cleavage and water gas shift of the CO intermediate. The rate limiting step on Pt surfaces is the initial dehydrogenation, while C--C cleavage appears rate limiting over NiSn catalysts. Tin promotion of Raney Ni catalysts suppresses C--O bond scission reactions that lead to alkane formation without inhibiting fast C--C and C--H cleavage steps that are necessary for high rates of reforming. A window of operating temperature, pressure, and reactor residence time has been identified for use of the inexpensive NiSn catalysts as a Pt substitute. Concentrated feed stocks and aggressive pretreatments have been found to counteract catalyst deactivation by sintering in the hydrothermal APR environment and allow stable, long-term production of H

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

    DEFF Research Database (Denmark)

    Kuld, Sebastian; Moses, Poul Georg; Sehested, Jens;

    2014-01-01

    Methanol has recently attracted renewed interest because of its potential importance as a solar fuel.1 Methanol is also an important bulk chemical that is most efficiently formed over the industrial Cu/ZnO/Al2O3 catalyst. The identity of the active site and, in particular, the role of ZnO...... as a promoter for this type of catalyst is still under intense debate.2 Structural changes that are strongly dependent on the pretreatment method have now been observed for an industrial-type methanol synthesis catalyst. A combination of chemisorption, reaction, and spectroscopic techniques provides...

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

    DEFF Research Database (Denmark)

    Kuld, Sebastian; Moses, Poul Georg; Sehested, Jens;

    2014-01-01

    Methanol has recently attracted renewed interest because of its potential importance as a solar fuel. Methanol is also an important bulk chemical that is most efficiently formed over the industrial Cu/ZnO/Al2O3 catalyst. The identity of the active site and, in particular, the role of ZnO...... as a promoter for this type of catalyst is still under intense debate. Structural changes that are strongly dependent on the pretreatment method have now been observed for an industrial-type methanol synthesis catalyst. A combination of chemisorption, reaction, and spectroscopic techniques provides a consistent...

  20. Commercial application of PAN-01 primary reforming catalyst in large scale ammonia plant%PAN -01型一段转化催化剂在大型合成氨装置的工业应用

    Institute of Scientific and Technical Information of China (English)

    张明松

    2014-01-01

    介绍新型低水碳比 PAN -01型一段转化催化剂的技术特点,通过实验比较 PAN -01催化剂和参比催化剂的主要技术参数,结果表明,PAN -01型一段催化剂具有更强的活性、抗析炭能力和径向抗压碎力,在大型合成氨装置工业应用过程中,效果较好,满足生产工艺各项要求。%The technique characteristics of PAN-01 primary reforming catalyst under low water/ carbon ratio was introduced. The main technical parameters of PAN-01 catalyst and reference catalyst were com-pared by the experiments. The results of commercial application showed that PAN-01 catalyst had higher activity,better anti-carbon deposit ability,and stronger radial anti-crushing strength than these of refer-ence catalyst,and met the requirements of production process for ammonia synthesis.

  1. Pre-reforming of Liquefied Petroleum Gas over Magnesium Aluminum Mixed Oxide Supported Nickel Catalysts%镁铝混合氧化物负载镍催化剂上液化石油气的预重整

    Institute of Scientific and Technical Information of China (English)

    王新星; 汪学广; 尚兴付; 聂望欣; 邹秀晶; 鲁雄钢; 丁伟中

    2012-01-01

    采用共沉淀-浸渍法并在较低温度(400~700℃)下焙烧制备了镁铝混合氧化物(MgmAl)负载的Ni催化剂.X射线衍射和程序升温还原结果表明,Ni物种高度分散于催化剂表面,没有形成尖晶石NiAl2O4.在650℃可被还原成金属Ni纳米晶粒,在400℃和较低水/碳摩尔比(S/C=2)条件下表现出较好的催化液化石油气(LPG)重整反应性能.详细考察了Mg/Al摩尔比、Ni负载量、载体和催化剂的焙烧温度对催化剂活性和稳定性的影响,结果表明,由500℃焙烧的Mg1.25Al载体负载的15%Ni催化剂,并于500℃焙烧时,在LPG重整反应中表现出最优的性能,尽管它比高温(≥800℃)焙烧制备的Ni/MgmAl催化剂更易积炭,催化活性和稳定性有所下降,但由于还原温度较低,在交通和小规模供电的燃料电池领域更具实际应用意义.%The catalytic performance of Ni catalysts supported on magnesium aluminum mixed oxide (Ni/MgmAl) for the pre-reforming of liquefied petroleum gas (LPG) was studied, and the catalysts were prepared by the co-precipitation-impregnation method and calcined in the lower temperature range of 400-700 ℃. The X-ray diffraction and H2 temperature-programmed reduction results showed that Ni species were highly dispersed on the catalyst surface without NLAl2O4 spinel formation. The Ni/MgmAl catalysts could be reduced to metallic Ni nanoparticles at 650 ℃, which showed excellent catalytic activity and stability for LPG pre-reforming at 400 ℃ and a low steam/carbon molar ratio of 2.0. The effects of Mg/Al molar ratios, Ni loading, and calcination temperature of the support and catalyst on the catalytic behavior of the Ni/MgmAl catalysts were investigated in detail. The results revealed that the 15%Ni/Mg1.25Al catalyst with both support and catalyst calcined at 500 ℃ had the optimal catalytic performance for LPG pre-reforming. Compared with Ni/MgmAl catalysts calcined at high temperature (> 800 ℃), the present

  2. Steam Reforming of Dimethyl Ether over Coupled Catalysts of CuO-ZnO-Al2O3-ZrO2 and Solid-acid Catalyst%二甲醚水蒸气重整制氢CuO-ZnO-Al2O3-ZrO2/固体酸复合催化剂

    Institute of Scientific and Technical Information of China (English)

    冯冬梅; 左宜赞; 王德峥; 王金福

    2009-01-01

    Steam reforming (SR) of dimethyl ether (DME) was investigated for the production of hydrogen for fuel cells. The activity of a series of solid acids for DME hydrolysis was investigated. The solid acid catalysts were ZSM-5[Si/Al= 25, 38 and 50: denoted Z(Si/Al)] and acidic alumina (γ-Al2O3) with an acid strength order that was Z(25)>Z(38)>Z(50)>γ-Al2O3. Stronger acidity gave higher DME hydrolysis conversion. Physical mixtures containing a CuO-ZnO-Zl2O3-ZrO2 catalyst and solid acid catalyst to couple DME hydrolysis and methanol SR were used to examine the acidity effects on DME SR. DME SR activity strongly depended on the activity for DME hydrolysis. Z(25) was the best solid acid catalyst for DME SR and gave a DME conversion>90% [T= 240℃,n(H2O)/n(DME) = 3.5, space velocity = 1179 ml·(g cat) -1·h-1, and P= 0.1MPa]. The influences of the reaction temperature, space velocity and feed molar ratio were studied. Hydrogen production significantly depended on temperature and space velocity. A bifunctional catalyst of CuO-ZnO-Al2O3-ZrO2 catalyst and ZSM-5 gave a high H2 production rate and CO2 selectivity.

  3. Steam Reforming of Dimethyl Ether over Coupled ZSM-5 and Cu-Zn-Based Catalysts%二甲醚水蒸气重整制氢的ZSM-5和Cu-Zn的复合催化体系

    Institute of Scientific and Technical Information of China (English)

    冯冬梅; 左宜赞; 王德峥; 王金福

    2009-01-01

    Dimethyl ether (DME) steam reforming (SR) is one possible source of hydrogen for fuel cells. The synergistic effect of catalyst coupling for the DME SR process and the coupling of reaction-heat transfer was studied. A DME hydrolysis catalyst comprising ZSM-5 (Si/A; = 25) and a series of methanol steam reforming catalysts (a series of Cu-Zn-based catalysts and a commercial Cu-Zn-Al catalyst) were used for DME SR. The evaluation of catalytic activity was conducted in a fixed-bed reactor. The catalysts were characterized by scanning electron microscopy, X-ray diffraction, and N2 adsorption. The activity and selectivity were influenced by the catalyst composition and copper content, and also the content of Al and Zr. A Cu:Zn molar ratio of 60:30 together with Al and Zr gave the best dispersion of Cu crystals and the highest low-temperature catalytic activity, with a DME conversion of 72% at 260℃ and a space velocity of 4 922 ml/(g·h).%二甲醚水蒸气重整制氢反应是燃料电池理想的供氢方式之一.探讨了二甲醚水蒸气重整过程中的反应与反应、反应与传热的耦合协同效应.采用二甲醚水解催化剂ZSM-5(硅铝比为25)和甲醇水蒸气重整催化剂(Cu-Zn系列及商用Cu-Zn-Al催化剂)混合制得二甲醚水蒸气重整的复合催化剂.在固定床反应装置中评价了催化剂活性并对催化剂进行了透射电镜、X射线衍射及N2吸附表征.结果表明,复合催化剂的活性除了受催化剂组成和铜含量的影响外,还与Al和Zr的量有关.在Cu:Zn摩尔比为60:30时,Al和Zr的同时加入使催化剂中Cu晶粒分散最好,催化剂具有较高的低温活性,二甲醚在空速为4 922 ml/(g·h)和260℃下的转化率达到72%.

  4. Widely tunable alloy composition and crystal structure in catalyst-free InGaAs nanowire arrays grown by selective area molecular beam epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Treu, J., E-mail: Julian.Treu@wsi.tum.de, E-mail: Gregor.Koblmueller@wsi.tum.de; Speckbacher, M.; Saller, K.; Morkötter, S.; Xu, X.; Riedl, H.; Abstreiter, G.; Finley, J. J.; Koblmüller, G., E-mail: Julian.Treu@wsi.tum.de, E-mail: Gregor.Koblmueller@wsi.tum.de [Walter Schottky Institut, Physik Department, Center of Nanotechnology and Nanomaterials, Technische Universität München, Am Coulombwall 4, Garching 85748 (Germany); Döblinger, M. [Department of Chemistry, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, Munich 81377 (Germany)

    2016-02-01

    We delineate the optimized growth parameter space for high-uniformity catalyst-free InGaAs nanowire (NW) arrays on Si over nearly the entire alloy compositional range using selective area molecular beam epitaxy. Under the required high group-V fluxes and V/III ratios, the respective growth windows shift to higher growth temperatures as the Ga-content x(Ga) is tuned from In-rich to Ga-rich InGaAs NWs. Using correlated x-ray diffraction, transmission electron microscopy, and micro-photoluminescence spectroscopy, we identify structural defects to govern luminescence linewidths in In-rich (x(Ga) < 0.4) and Ga-rich (x(Ga) > 0.6) NWs, whereas limitations at intermediate Ga-content (0.4 < x(Ga) < 0.6) are mainly due to compositional inhomogeneities. Most remarkably, the catalyst-free InGaAs NWs exhibit a characteristic transition in crystal structure from wurtzite to zincblende (ZB) dominated phase near x(Ga) ∼ 0.4 that is further reflected in a cross-over from blue-shifted to red-shifted photoluminescence emission relative to the band edge emission of the bulk ZB InGaAs phase.

  5. Estudio de Catalizadores de Rutenio para la obtención de Gas de Síntesis a partir del Reformado Seco de Metano A Study on Ruthenium Catalysts to Obtain SynGas by Dry Methane Reforming

    Directory of Open Access Journals (Sweden)

    Silvia C.P Maina

    2009-01-01

    Full Text Available En este trabajo se estudia el comportamiento catalítico en reformado seco de catalizadores de Ru soportados sobre alúminas con agregado de Na, K, Mg, Ca o Ba. Los soportes y catalizadores fueron caracterizados y se analizó el comportamiento catalítico en la reacción de reformado de CH4 con CO2. Los catalizadores Ru/Al2O3-Na y Ru/Al2O3-K ofrecen mayores conversiones y mejores relaciones H2/CO, asunto que está relacionado con la dispersión metálica y con la basicidad del soporte. La disminución del tiempo de reducción previa del catalizador en H2, produce una disminución de las conversiones de CO2 y CH4 para todos los catalizadores excepto para el Ru/Al2O3-Na. Este fenómeno no sería debido al efecto térmico sino al tiempo de reducción propiamente dicho.This work studies the catalytic performance in dry reforming of Ru catalysts supported on γ-Al2O3 promoted with Na, K, Mg, Ca and Ba. The supports and the catalysts were characterized and tested in the reaction of CH4 reforming with CO2. Ru/Al2O3-Na and Ru/Al2O3-K catalysts showed higher conversions and better H2/CO molar ratios. This catalytic behavior would be related with the higher metallic dispersions and with the basicity of the support. When the reduction time in H2 was shortened, a decrease of the conversions for all the catalysts, except for Ru/Al2O3-Na, was observed. This phenomenon would not be due to the thermal effect but to the reduction time.

  6. 甲烷与二氧化碳催化重整制取合成气催化剂%Catalysts for Carbon Dioxide Catalytic Reforming of Methane to Synthesis Gas

    Institute of Scientific and Technical Information of China (English)

    王莉; 敖先权; 王诗瀚

    2012-01-01

    甲烷自然资源丰富,并且也可利用生物质通过发酵制备,而将甲烷与二氧化碳催化重整制取合成气是同时利用两种温室气体的一条有效途径,对清洁能源和环保具有重大意义。近年来,由于该方法与其他技术相比具有较大优势,催化剂、反应机理及一些非常规手段的研究引起了科学界广泛关注。本文概述了近几年来甲烷与二氧化碳催化重整催化剂的活性组分、载体、助催化剂、催化剂积炭行为及制备方法等研究新进展,归纳了影响催化剂抗积炭能力的因素,重点介绍了负载型双金属催化剂、复合氧化物催化剂、介孔型催化剂、金属氧化物载体的活性及稳定性,催化剂制备方法对催化活性和抗积炭能力的影响,催化剂抗积炭方法及等离子体技术的应用等研究,包括普遍认为反应主要受到表面氧原子、表面氢原子与催化剂表面活性位三者影响的反应机理,并展望了双金属催化剂、钙钛矿型催化剂、介孔型催化剂及等离子体协同催化技术的应用及催化机理的研究等发展前景。%The natural resources of methane are abundant,and methane also can be produced from biomass by fermentation process. It is an effective way to use two kinds of greenhouse gases simultaneously through preparation of synthesis gas by CH4-CO2 catalytic reforming, so this technique has a great significance to clean energy and environment protection. In recent years, a great attention has been paid to the catalysts, reaction mechanism and some unconventional means of this process due to their greater advantages compared to other methane conversion techniques. The recent studies in catalysts of this process including catalytic active components, supports, additives, carbon deposition of catalyst and catalyst preparation methods are reviewed in this paper. A series of influencing factors in the resistance to carbon deposition are summarized. The

  7. Investigation by Mössbauer spectroscopy of Sn redox transformations during H2/O2 titration on Pt/Al2O3Sn-Cl and Pt/Al2O3SnIn-Cl naphtha reforming catalysts

    Science.gov (United States)

    Jahel, Ali; Avenier, Priscilla; Lacombe, Sylvie; Olivier-Fourcade, Josette; Jumas, Jean-Claude

    2010-03-01

    Bimetallic Pt/Al2O3Sn-Cl and trimetallic Pt/Al2O3SnIn-Cl catalysts were characterized by H2/O2 double titration and 119Sn Mössbauer spectroscopy. The addition of Sn or both Sn and In to the monometallic Pt/Al2O3-Cl catalyst leads to an increase in the volume of chemisorbed O2 at each titration. For bimetallic and trimetallic catalysts the increase in the Pt dispersion, calculated from the second oxygen titre, abnormally surpasses the barrier of 100%. Characterization of samples obtained after each step of the H2/O2 titration sequence using 119Sn Mössbauer spectroscopy allowed to follow the redox transformations of Sn species suspected of contributing to O2 consumption. 119Sn Mössbauer spectra show that after reduction unalloyed metalic Sn and PtSn alloy phases are formed in bi- and trimetallic catalysts respectively. These metallic phases are oxidized upon the first oxygen titre into the so-called PtxSn(O) oxometalic phases. The index calculated from this titre thus expresses the Pt-Sn bimetallic character and is called the bimetallicity index (BMI). These latter phases further undergo reduction and regeneration (oxidation) upon the second O2 titre and thus contribute to the calculated Pt dispersion as well.

  8. Study and modelling of deactivation by coke in catalytic reforming of hydrocarbons on Pt-Sn/Al{sub 2}O{sub 3} catalyst; La microbalance inertielle: etude et modelisation cinetique de la desactivation par le coke en reformage catalytique des hydrocarbures sur catalyseur Pt-Sn/Al{sub 2}O{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Mathieu-Deghais, S.

    2004-07-01

    Catalytic reforming is the refining process that produces gasoline with a high octane number. During a reforming operation, undesired side reactions promote the formation of carbon deposits (coke) on the surface of the catalyst. As the reactions proceed, the coke accumulation leads to a progressive decrease of the catalyst activity and to a change in its selectivity. Getting this phenomenon under control is interesting to optimize the industrial plants. This work aims to improve the comprehension and the modeling of coke formation and its deactivating effect on reforming reactions, while working under conditions chosen within a range as close as possible to the industrial conditions of the regenerative process. The experimental study is carried out with a micro unit that is designed to observe simultaneously the coke formation and its influence on the catalyst activity. A vibrational microbalance reactor (TEOM - Tapered Element Oscillating Microbalance) is used to provide continuous monitoring of coke. On-line gas chromatography is used to observe the catalyst activity and selectivity as a function of the coke content. The coking experiments are performed on a fresh Pt-Sn/alumina catalyst, with mixtures of hydrocarbon molecules of 7 carbon atoms as hydrocarbon feeds. The coking tests permitted to highlight the operating parameters that may affect the amount of coke, and to identify the hydrocarbon molecules that behave as coke intermediate. A kinetic model for coke formation could be developed through the compilation of these results. The catalytic activity analysis permitted to point out the coke effect on both of the active phases of the catalyst, to construct a simplified reforming kinetic model that simulates the catalyst activity under the reforming conditions, and to quantify deactivation via deactivation functions. (author)

  9. Effect of Y{sub 2}O{sub 3} addition to Rh/Al{sub 2}O{sub 3} catalysts on the autothermal reforming of methane; Efeito da adicao de Y{sub 2}O{sub 3} a catalisadores de Rh/Al{sub 2}O{sub 3} na reforma autotermica do metano

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, Vanessa Monteiro; Cardoso, Gabriel Alexandre Lima; Coutinho, Ana Carla da S. Lomba S.; Passos, Fabio Barboza [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Dept. de Engenharia Quimica e de Petroleo. Lab. de Reatores, Cinetica e Catalise (RECAT)]. E-mail: vanessafisqui@yahoo.com.br

    2008-07-01

    In this work, the effect of the addition of Y{sub 2}O{sub 3} (with 2%, 5% and 10% weight content) on Rh/{alpha}-Al{sub 2}O{sub 3} catalysts in the autothermal reforming reaction of methane to the production of hydrogen for fuel cells was investigated. The catalysts were characterized by the following techniques: N{sub 2} adsorption, H{sub 2} chemisorption, X-ray diffraction (XRD) and cyclohexane dehydrogenation reaction. The catalysts were also evaluated in the reaction of autothermal reforming. The catalyst with higher Y{sub 2}O{sub 3} content showed the best results both in the cyclohexane dehydrogenation rate and in the conversion of methane. (author)

  10. Determination of Chlorine in Reforming Catalyst by Ion Chromatography with Eluent Autogeneration%淋洗液自动发生-离子色谱法测定重整催化剂中氯的含量

    Institute of Scientific and Technical Information of China (English)

    赵雅郡; 谢莉; 周勇; 冯移丽

    2011-01-01

    建立了重整催化剂中氯含量的淋洗液自动发生-离子色谱测定方法.以4 mL 7.5 mol/L NaOH溶液提取重整催化剂中Cl-,以淋洗液自动发生装置产生的KOH溶液为流动相,进行离子色谱法测定.结果表明,溶液中Cl-线性关系良好,相关系数为0.9999,测定结果的RSD小于0.76%,加标回收率为98.7%~102.8%.%A method for determination of chlorine in reforming catalyst by ion chromatography with eluent autogeneration was established. Chlorine in reforming catalyst was extracted by 4 mL sodium hydroxide solution of 7.5 mol/L, and determined by ion chromatography using potassium hydroxide solution generated by eluent generator as mobile phase. The linear relation of chlorine of solution was good, the correlation coefficient was 0.9999. The relative standard deviation was less than 0.8%, the recoveries were 98.7% to 102.8%. The method is simple and accurate.

  11. Correlation between diffusion barriers and alloying energy in binary alloys

    DEFF Research Database (Denmark)

    Vej-Hansen, Ulrik Grønbjerg; Rossmeisl, Jan; Stephens, Ifan;

    2016-01-01

    In this paper, we explore the notion that a negative alloying energy may act as a descriptor for long term stability of Pt-alloys as cathode catalysts in low temperature fuel cells.......In this paper, we explore the notion that a negative alloying energy may act as a descriptor for long term stability of Pt-alloys as cathode catalysts in low temperature fuel cells....

  12. Use of Hydrogen Chemisorption and Ethylene Hydrogenation as Predictors for Aqueous Phase Reforming of Lactose over Ni@Pt and Co@Pt Bimetallic Overlayer Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Lai, Qinghua; Skoglund, Michael D.; Zhang, Chen; Morris, Allen R.; Holles, Joseph H.

    2016-10-20

    Overlayer Pt on Ni (Ni@Pt) or Co (Co@Pt) were synthesized and tested for H2 generation from APR of lactose. H2 chemisorption descriptor showed that Ni@Pt and Co@Pt overlayer catalysts had reduced H2 adsorption strength compared to a Pt only catalyst, which agree with computational predictions. The overlayer catalysts also demonstrated lower activity for ethylene hydrogenation than the Pt only catalyst, which likely resulted from decreased H2 binding strength decreasing the surface coverage of H2. XAS results showed that overlayer catalysts exhibited higher white line intensity than the Pt catalyst, which indicates a negative d-band shift for the Pt overlayer, further providing evidence for overlayer formation. Lactose APR studies showed that lactose can be used as feedstock to produce H2 and CO under desirable reaction conditions. The Pt active sites of Ni@Pt and Co@Pt overlayer catalysts showed significantly enhanced H2 production selectivity and activity when compared with that of a Pt only catalyst. The single deposition overlayer with the largest d-band shift showed the highest H2 activity. The results suggest that overlayer formation using directed deposition technique could modify the behavior of the surface metal and ultimately modify the APR activity.

  13. Reformer Fuel Injector

    Science.gov (United States)

    Suder, Jennifer L.

    2004-01-01

    Today's form of jet engine power comes from what is called a gas turbine engine. This engine is on average 14% efficient and emits great quantities of green house gas carbon dioxide and air pollutants, Le. nitrogen oxides and sulfur oxides. The alternate method being researched involves a reformer and a solid oxide fuel cell (SOFC). Reformers are becoming a popular area of research within the industry scale. NASA Glenn Research Center's approach is based on modifying the large aspects of industry reforming processes into a smaller jet fuel reformer. This process must not only be scaled down in size, but also decrease in weight and increase in efficiency. In comparison to today's method, the Jet A fuel reformer will be more efficient as well as reduce the amount of air pollutants discharged. The intent is to develop a 10kW process that can be used to satisfy the needs of commercial jet engines. Presently, commercial jets use Jet-A fuel, which is a kerosene based hydrocarbon fuel. Hydrocarbon fuels cannot be directly fed into a SOFC for the reason that the high temperature causes it to decompose into solid carbon and Hz. A reforming process converts fuel into hydrogen and supplies it to a fuel cell for power, as well as eliminating sulfur compounds. The SOFC produces electricity by converting H2 and CO2. The reformer contains a catalyst which is used to speed up the reaction rate and overall conversion. An outside company will perform a catalyst screening with our baseline Jet-A fuel to determine the most durable catalyst for this application. Our project team is focusing on the overall research of the reforming process. Eventually we will do a component evaluation on the different reformer designs and catalysts. The current status of the project is the completion of buildup in the test rig and check outs on all equipment and electronic signals to our data system. The objective is to test various reformer designs and catalysts in our test rig to determine the most

  14. Co/ZnO and Ni/ZnO catalysts for hydrogen production by bioethanol steam reforming. Influence of ZnO support morphology on the catalytic properties of Co and Ni active phases

    Energy Technology Data Exchange (ETDEWEB)

    Da Costa-Serra, J.F.; Chica, A. [Instituto de Tecnolgia Quimica (UPV-CSIC), Universidad Politecnica de Valencia, Consejo Superior de Investigaciones Cientificas, Avenida de los naranjos s/n, 46022 Valencia (Spain); Guil-Lopez, R. [Instituto de Catalisis y Petroleoquimica, CSIC, Marie Curie 2, Cantoblanco, 28049 Madrid (Spain)

    2010-07-15

    Renewable hydrogen production from steam reforming of bioethanol is an interesting approach to produce sustainable hydrogen. However, simultaneous competitive reactions can occur, decreasing the hydrogen production yield. To overcome this problem, modifications in the steam reforming catalysts are being studied. Ni and Co active phases supported over modified ZnO have been widely studied in hydrogen production from steam reforming of bioethanol. However, the influence of the morphology and particle size of ZnO supports on the catalytic behaviour of the supported Ni and Co has not been reported. In the present work, we show how the morphology, shape, and size of ZnO support particles can control the impregnation process of the metal active centres, which manages the properties of active metallic particles. It has been found that nanorod particles of ZnO, obtained by calcination of Zn acetate, favour the metal-support interactions, decreasing the metallic particle sizes and avoiding metal (Co or Ni) sinterization during the calcination of metal precursors. Small metallic particle sizes lead to high values of active metal exposure surface, increasing the bioethanol conversion and hydrogen production. (author)

  15. BTX production by in-situ contact reforming of low-temperature tar from coal with zeolite-derived catalysts; Zeolite kei shokubai wo mochiita sekitan teion tar no sesshoku kaishitsu ni yoru BTX no seisei

    Energy Technology Data Exchange (ETDEWEB)

    Matsunaga, T.; Fuda, K.; Murakami, K.; Kyo, M.; Hosoya, S.; Kobayashi, S. [Akita University, Akita (Japan). Mining College

    1996-10-28

    On BTX production process from low-temperature tar obtained by pyrolysis of coal, the effect of exchanged metallic species and reaction temperature were studied using metallic ion-exchanged Y-zeolite as catalyst. In experiment, three kinds of coals with different produced tar structures such as Taiheiyo and PSOC-830 sub-bituminous coals and Loy Yang brown coal were used. Y-zeolite ion-exchanged with metal chloride aqueous solution was used as catalyst. Zn{sup 2+}, Ni{sup 2+} and In{sup 3+} were used as metal ions to be exchanged. The experiment was conducted by heating a pyrolysis section up to 600{degree}C for one hour after preheating a contact reforming section up to a certain proper temperature. As a result, the Ni system catalyst was effective for BTX production from aromatic-abundant tar, while the Zn system one from lower aromatic tar. In general, relatively high yields of toluene and xylene were obtained at lower temperature, while those of benzene at higher temperature. 4 figs., 1 tab.

  16. A highly active catalyst, Ni/Ce-ZrO{sub 2}/{sup t}heta{sup -}Al{sub 2}O{sub 3}, for on-site H{sub 2} generation by steam methane reforming: pretreatment effect

    Energy Technology Data Exchange (ETDEWEB)

    Youngsam Oh; Youngsoon Baek [Korea Gas Corp., Incheon (Korea). LNG Technology Research Center; HyunSeog Roh; Kiwon Jun [Korea Research Inst. of Chemical Technology, Daejong (Korea). Chemical Technology Division

    2003-12-01

    The steam treatment effect has been investigated over the doubly impregnated catalyst, Ni/Ce-ZrO{sub 2}/{theta}-Al{sub 2}O{sub 3}, in steam methane reforming (SMR). The catalyst was remarkably deactivated by steam treatment but reversibly regenerated by H{sub 2}-reduction. XRD results showed that the steam treatment resulted in the formation of NiAl{sub 2}O{sub 4} which is inactive for SMR but it was reversibly converted to Ni by the reduction. The reversible oxidation/reduction of Ni state was also evidenced by XPS and it was observed that the formation of NiAl{sub 2}O{sub 4} is more favorable at higher temperature. It is most likely that the alumina support is only partially covered with Ce-ZrO{sub 2} and most Ni directly interacts with {theta}-Al{sub 2}O{sub 3} which would probably make easy formation of NiAl{sub 2}O{sub 4} in the presence of steam alone. The results imply that, during the start-up procedure in SMR, too high concentration of steam could deactivate seriously Al{sub 2}O{sub 3} supported Ni catalysts. (author)

  17. Hydrogen Production by Steam Reforming of Glycerin Over Ni,Co,Fe Catalysts%甘油水蒸汽重整制氢Ni、Co、Fe催化剂的研究

    Institute of Scientific and Technical Information of China (English)

    李俊磊; 李晓香; 李冬锋; 郭瓦力

    2014-01-01

    All catalysts were prepared by isovolumetric mpregnation method,and activities of prepared Ni/Al2O3, Fe/Al2O3, CoMo/Al2O3 and NiCo/Al2O3 catalysts were studied for hydrogen production by steam reforming of glycerol. All catalysts were characterized BET, XRD and H2-TPR.The catalysts were evaluated by using hydrogen yield as index. The results show that, the maximum H2 yield(6.02)can be obtained at 650 ℃ with CoMo/Al2O3 catalyst;the maximum H2 yield(6.08) can be obtained with NiCo/Al2O3 catalyst under the conditions of 600℃, steam-methanol ratio 16, WHSV 0.12 h-1;Catalyst activity sequence NiCo/Al2O3>Co-Mo/Al2O3>Ni/Al2O3>Fe/Al2O3.%采用等体积浸渍法制备了催化剂,研究了 Ni/Al2O3,Fe/Al2O3,CoMo/Al2O3和 NiCo/Al2O3催化剂对甘油水蒸汽重整制氢反应的催化效果,对催化剂进行BET、TPR、XRD表征,以氢产率为实验指标对催化剂进行了评价。研究结果表明,CoMo/Al2O3催化剂在温度650℃氢产率6.02。NiCo/Al2O3催化剂在温度600℃、水醇比16、液空速0.12 h-1条件下的氢产率为6.08。催化剂活性次序为NiCo/Al2O3>Co-Mo/Al2O3>Ni/Al2O3>Fe/Al2O3。

  18. Synthesis and characterization of Pt-Sn-Ni alloys to application as catalysts for direct ethanol fuel cells; Sintese e caracterizacao de ligas de Pt-Sn-Ni para aplicacao como caztalisadores em celulas a combustivel do tipo DEFC

    Energy Technology Data Exchange (ETDEWEB)

    Silva, E.L. da; Correa, P.S.; Oliveira, E.L. de; Takimi, A.S.; Malfatti, C.F., E-mail: celia.malfatti@ufrgs.b [Universidade Federal do Rio Grande do Sul (LAPEC/UFRGS), Porto Alegre, RS (Brazil). Programa de Pos-Graduacao em Engenharia Mecanica. Lab. de Pesquisa em Corrosao; Radtke, C. [Universidade Federal do Rio Grande do Sul (IQ/UFRGS), Porto Alegre, RS (Brazil). Inst. de Quimica

    2010-07-01

    Direct ethanol fuel cells (DEFCs) have been the focus of recent research due its application in mobile energy sources. In order to obtain the maximum efficiency from these systems, it is necessary the total ethanol oxidation, which implies in C-C bond break. Different catalysts described in literature are employed with this intent. This work consists in studying PtSnNi catalysts supported on carbon Vulcan XC72R, to application in DEFCs. Thus, it was used the impregnation/reduction method, varying the atomic proportion among Pt, Sn and Ni. The alloys were characterized by X-Ray Diffraction, Cyclic Voltammetry and Transmission Microscopy. Preliminary results show that predominant structure on the catalysts is the face centered cubic platinum and the densities currents are dependent on the platinum amount. (author)

  19. Development of GREET Catalyst Module

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhichao [Argonne National Lab. (ANL), Argonne, IL (United States); Benavides, Pahola T. [Argonne National Lab. (ANL), Argonne, IL (United States); Dunn, Jennifer B. [Argonne National Lab. (ANL), Argonne, IL (United States); Cronauer, Donald C. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2015-09-01

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

  20. Characterization of catalysts Rh and Ni/Ce{sub x}Zr{sub 1-x}O{sub 2} for hydrogen production by ethanol steam reforming; Caracterisation de catalyseurs Rhodium et Nickel/ Ce{sub x}Zr{sub 1-x}O{sub 2} pour la production d'hydrogene par vaporeformage de l'ethanol

    Energy Technology Data Exchange (ETDEWEB)

    Birot, A

    2005-07-01

    This work concerned a study on catalytic behaviour of metallic catalysts (Rh or Ni) supported on earth rare oxides Ce{sub x}Zr{sub 1-x}O{sub 2} in ethanol steam reforming in order to produce hydrogen. Catalyst 1%Rh/Ce0,50Zr0,50O{sub 2} showed a good activity with a good hydrogen yield. We turned a study onto understanding inter-conversion reaction between H{sub 2}, CO and CO{sub 2} which lead to CH{sub 4} formation. We also studied intrinsic properties of catalysts. We confirmed basic character of catalysts and a good hydrogenation activity. A good activity in CO hydrogenation allowed to evidence a necessity to use a catalyst which is less active in hydrogenation reaction and with a basic character in order to improve hydrogen yield. (author)

  1. 催化剂制备方法对甘油液相重整制氢反应的影响%Influence of preparation methods of the catalyst on hydrogen production from aqueous-phase reforming of glycerol

    Institute of Scientific and Technical Information of China (English)

    江涛; 韩林芯; 于恺; 董朝辉; 王轲; 李涛; 曹发海

    2012-01-01

    Great attention to the shortage of energy resources and environmental problems has been paid. Seeking and utilizing renewable and sustainable green energy resources are focused on by human society. It is a technical process of ecological resource utilization to employ glycerol derived from biomass as the raw materials to generate hydrogen by aqueous-phase reforming. For this purpose, NiCoAl complex oxide catalysts were prepared by using co-precipitation and impregnation methods, and the influence of calcination temperature was also investigated. The structural properties of catalysts were characterized by XRD, TG-DTG and BET. The results showed that compared with impregnation method, NiCoAl complex oxide catalyst prepared by co-precipitation method exhibited higher activities for hydrogen production, and the optimum calcination temperature of the catalyst was 550℃.%能源紧缺和环境问题已成为全世界关注的话题,开发利用可再生的清洁能源备受关注,甘油水溶液催化重整制氢是一条资源利用生态化的工艺路线.分别采用共沉淀法和浸渍法制备了NiCoAl复合氧化物催化剂,并采用XRD、比表面积及热分析等对催化剂进行结构表征,结合甘油液相重整制氢中催化剂活性测试结果表明,共沉淀法制得的NiCoAl复合氧化物催化剂的活性较好,较适宜的焙烧温度为550℃.

  2. Ceramic oxygen transport membrane array reactor and reforming method

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, Sean M.; Christie, Gervase Maxwell; Rosen, Lee J.; Robinson, Charles; Wilson, Jamie R.; Gonzalez, Javier E.; Doraswami, Uttam R.

    2016-09-27

    A commercially viable modular ceramic oxygen transport membrane reforming reactor for producing a synthesis gas that improves the thermal coupling of reactively-driven oxygen transport membrane tubes and catalyst reforming tubes required to efficiently and effectively produce synthesis gas.

  3. Development of Cu and Ni catalysts supported on ZrO{sub 2} for the generation of H{sub 2} by means of the reaction of reformed methanol in atmosphere oxidizer; Desarrollo de catalizadores de Cu y Ni soportados en ZrO{sub 2} para la generacion de H{sub 2} mediante la reaccion de reformado de metanol en atmosfera oxidante

    Energy Technology Data Exchange (ETDEWEB)

    Lopez C, P.

    2012-07-01

    ZrO{sub 2} was prepared by the sol-gel method and calcined at 450 C. The prepared zirconia was impregnated with an aqueous solution of Cu(CH{sub 3}CO{sub 2}){sub 2}{center_dot}H{sub 2}O or NiNO{sub 3}{center_dot}6H{sub 2}O at an appropriate concentration to yield 3 wt % of copper or nickel, respectively, in the mono metallic catalysts. Three bimetallic samples were prepared at 80% Cu and 20% Ni respectively to obtain 3 wt % of total metallic phase. Surface area of the Cu-Ni base catalysts supported on ZrO{sub 2} oxide showed differences as a function of the metal addition. Between them, the Cu/ZrO{sub 2} catalyst had the lowest surface area than other catalysts. X-ray diffraction patterns of the bimetallic catalysts did not show diffraction peaks of the Cu, Ni or bimetallic Cu-Ni alloys. In addition, TPR profiles of the bimetallic catalysts had the lowest reduction temperature compared with the mono metallic samples. The reactivity of the catalysts in the range of 250-350 C showed that the samples prepared by successive impregnation had the highest catalytic activity than the other catalysts studied. Also the selectivity for H{sub 2} production was higher for these catalysts. This finding was associated to the presence of the bimetallic Cu-Ni nanoparticles, as was evidenced by Tem-EDX analysis. (Author)

  4. Novel catalytic materials for carbon dioxide reforming of methane under severely deactivating conditions

    Science.gov (United States)

    Stagg-Williams, Susan Michelle

    In recent years, the utilization of carbon dioxide for the reforming of methane (dry reforming) has attracted significant interest due to the industrial advantages over conventional steam reforming. The major obstacle preventing commercialization of this process is the lack of a catalyst capable of operating at the high temperatures and pressures required by industry. This thesis reports the study of the dry reforming reaction over SiO 2 and ZrO2 supported Pt catalysts. It was found that the Pt/ZrO2 catalyst had much higher activity and stability than the Pt/SiO2 catalyst due to the ability of the ZrO2 to adsorb CO2 near the metal particle, facilitating its dissociation. The decomposition of CH4 and the dissociation of CO2 occur via two independent pathways. CH4 decomposition occurs on the metal particle resulting in the formation of H2 and carbon deposition. When Pt is supported on ZrO2, the carbon formed during the decomposition of CH4 can reduce the support to form CO2 creating oxygen vacancies in the support lattice near the metal particle. The adsorption and dissociation of CO2 occurs at the vacancies, forming CO and replenishing the oxygen in the support lattice. This redox mechanism results in a cleaning of the metal particle by oxygen provided by the support. Promoters were added to both the metallic phase and to the support to improve the stability of the catalyst by decreasing carbon deposition. The co-impregnation of Sn and Pt on the ZrO2 resulted in lower activity and stability than the monometallic catalysts. Under oxidizing conditions, segregation of the Pt-Sn alloys occurred, resulting in the formation of tin oxide inhibiting the role of the ZrO2. Catalysts prepared by methods that allow for the controlled placement of Sn on the Pt particle, exhibited high activity and stability under severely deactivating conditions. Promotion of the ZrO2 support with cerium and lanthanum resulted in increased activity and stability of the catalyst. The improved

  5. Preparation and catalytic properties of ZrO2-Al2O3 composite oxide supported nickel catalysts for methane reforming with carbon dioxide

    Institute of Scientific and Technical Information of China (English)

    HAO Zheng-ping; HU Chun; JIANG Zheng; G. Q. LU

    2004-01-01

    ZrO2-Al2O3 composite oxides and supported Ni catalysts were prepared , and characterized by N2adsorption/desorption, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy ( XPS ) techniques. Thecatalytic performance and carbon deposition was also investigated. This mesoporous composite oxide is shown to bea promising catalyst support. An increase in the catalytic activity and stability of methane and carbon dioxidereforming reaction was resulted from the zirconia addition, especially at 5wt% ZrO2 content. The Ni catalystsupported ZrO2-Al2O3 has a strong resistance to sintering and the carbon deposition in a relatively long-termreaction.

  6. Hydrogen production for fuel cell by oxidative reforming of diesel surrogate: influence of ceria and/or lanthana over the activity of Pt/Al{sub 2}O{sub 3} catalysts

    Energy Technology Data Exchange (ETDEWEB)

    M.C. Alvarez-Galvan; R.M. Navarro; F. Rosa; Y. Briceno; M.A. Ridao; J.L.G. Fierro [Instituto de Catalisis y Petroleoquimica (CSIC), Madrid (Spain)

    2008-09-15

    A series of Pt catalysts supported on Al{sub 2}O{sub 3} (Pt/A), Al{sub 2}O{sub 3}-CeO{sub 2} (Pt/A-C), Al{sub 2}O{sub 3}-La{sub 2}O{sub 3} (Pt/A-L) and Al{sub 2}O{sub 3}-La{sub 2}O{sub 3}-CeO{sub 2} (Pt/A-L-C) have been prepared and tested in the oxidative reforming of diesel surrogate with the aim of studying the influence of ceria and lanthana additives over the activity and stability toward hydrogen production for fuel cell application. Several characterization techniques, such as adsorption-desorption of N{sub 2}, X-ray diffraction, X-ray photoelectron spectroscopy, temperature programmed reduction, H{sub 2} chemisorption, and thermogravimetric analysis, have been used to define textural, structural, and surface properties of catalysts and to establish relationships with their behaviour in reaction. This physicochemical characterization has shown that lanthana inhibits the formation of {alpha} phase in alumina support and decreases ceria dispersion. Activity results show a better performance of ceria-loaded catalysts, being the Pt/A-C sample the system that offers higher H{sub 2} yields after 8 h of reaction. The greater H{sub 2} production for ceria-loaded catalysts, particularly in the case of the system Pt/A-C, is attributed to the Pt-Ce interaction that may change the electronic properties and/or the dispersion of active metal phase. Also, the Ce{sup III} form of Ce{sup IV}/Ce{sup III} redox pair enhances the adsorption of oxygen and water molecules, thus increasing the catalytic activity and also decreasing coke deposition over surface active Pt phases. Stability tests showed that catalysts in which Pt crystallites are deposited on the alumina substrate covered by a lanthana monolayer, give rise to an increase in stability toward H{sub 2} production. 48 refs., 10 figs., 3 tabs.

  7. 天然气纯氧换热式转化工艺、催化剂及设备的应用%Use of Natural Gas Heat Transfer Reforming by Pure Oxygen Process, Catalyst and Equipment

    Institute of Scientific and Technical Information of China (English)

    魏有福

    2014-01-01

    介绍了天然气纯氧换热式转化装置的工艺流程、主要设备和催化剂应用情况。该装置设备材质及催化剂均实现国产化,运行状况良好。经多年节能挖潜改造,各项指标全面超过其设计值,吨氨消耗和综合能耗均低于Tandem工艺。%A introduction is given of the use of equipment and technological process for natural gas heat transfer reforming by pure oxygen, main equipment and catalyst.The material of the equipment and catalyst are realized localization, and the operation conditions are good.After many years of energy saving and tapping the potentials and transform, all indicators are excess their design values, consumption per ton ammonia and comprehensive energy consumption are lower than that of Tandem process.

  8. 低镍/ZnO-TiO2催化剂的乙醇水蒸气重整制氢%Hydrogen Production from Ethanol Steam Reforming over Low Nickel Content Ni/ZnO-TiO2 Catalysts

    Institute of Scientific and Technical Information of China (English)

    刘利平; 张鹏; 马晓建; 韩秀丽

    2011-01-01

    为考察低镍负载量对乙醇水蒸气重整制氢催化剂性能的影响,利用沉积-沉淀法(DP)制备了镍负载最质量分率为0.5%~5.0%的Ni/ZnO-TiO2催化剂,并在内径14 mm的固定床管式反应器中对低镍催化剂进行了性能评价.结果表明,低镍/ZnO-TiO2催化剂具有较好的乙醇水蒸气重整制氢性能.在水醇物质的量比为13:1及反应温度为400~550℃时,乙醇转化率均达到了90%以上,其中镍负载量为2%的催化剂有最好的催化性能.对镍负载量2%的2.ONi/ZnO-TiO2催化剂进行了X射线衍射(XRD)和扫描电镜(SEM)表征,分析结果表明,复合载体ZnO-TiO2负载的Ni基催化剂的晶体粒径为68~240 mm,活性组分Ni分散良好,反应后的催化剂上有积炭生成.%In order to explore the influence of low nickel loading on the characteristics of hydrogen production from ethanol steam reforming, Ni/ZnO-TiO2 catalysts in the nickel loading range 0.5%-5.0% were prepared by deposition-precipitation ( DP ) method, and the catalytic performances were evaluated in a φ14 mm fixed bed tube reactor. The results showed that Ni/ZnO-TiO2 catalysts have better catalytic performance for hydrogen production of ethanol steam reforming. Ethanol conversion was beyond 90% under the conditions of the molar ratio of water to ethanol of 13:1 and the reaction temperature of 400-550 ℃. The catalyst with 2% nickel loading showed the best catalytic performance comparatively. Catalyst with the nickel loading of 2% was by means of BET, x-ray diffraction (XRD) and scanning electron microscope (SEM). The results characterized by XRD and SEM indicated that the crystal sizes of Ni-based catalyst supported on composite support of ZnO-TiO2 were 68-240 nm, the active component nickel was dispersion well, and formation of carbon could found on used catalyst surface.

  9. Toward highly efficient in situ dry reforming of H2S contaminated methane in solid oxide fuel cells via incorporating a coke/sulfur resistant bimetallic catalyst layer

    NARCIS (Netherlands)

    Hua, B.; Yan, N.; Li, M.; Sun, Y.-F.; Chen, J.; Zhang, Y.-Q.; Li, J.; Etsell, T.; Sarkar, P.; Luo, J.L.

    2016-01-01

    The escalating global warming effects are a reason for immediate measures to reduce the level of greenhouse gases. In this context, dry reforming of methane (DRM), an old yet both scientifically and industrially important process, is making a comeback in contributing to the utilization of CO2. Howev

  10. Investigation of the Process Conditions for Hydrogen Production by Steam Reforming of Glycerol over Ni/Al2O3 Catalyst Using Response Surface Methodology (RSM

    Directory of Open Access Journals (Sweden)

    Ali Ebshish

    2014-03-01

    Full Text Available In this work; a response surface methodology (RSM was implemented to investigate the process variables in a hydrogen production system. The effects of five independent variables; namely the temperature (X1; the flow rate (X2; the catalyst weight (X3; the catalyst loading (X4 and the glycerol-water molar ratio (X5 on the H2 yield (Y1 and the conversion of glycerol to gaseous products (Y2 were explored. Using multiple regression analysis; the experimental results of the H2 yield and the glycerol conversion to gases were fit to quadratic polynomial models. The proposed mathematical models have correlated the dependent factors well within the limits that were being examined. The best values of the process variables were a temperature of approximately 600 °C; a feed flow rate of 0.05 mL/min; a catalyst weight of 0.2 g; a catalyst loading of 20% and a glycerol-water molar ratio of approximately 12; where the H2 yield was predicted to be 57.6% and the conversion of glycerol was predicted to be 75%. To validate the proposed models; statistical analysis using a two-sample t-test was performed; and the results showed that the models could predict the responses satisfactorily within the limits of the variables that were studied.

  11. Pyrometallurgical Recovery of Platinum Group Metals from Spent Catalysts

    Science.gov (United States)

    Peng, Zhiwei; Li, Zhizhong; Lin, Xiaolong; Tang, Huimin; Ye, Lei; Ma, Yutian; Rao, Mingjun; Zhang, Yuanbo; Li, Guanghui; Jiang, Tao

    2017-09-01

    As an important secondary resource with abundant platinum group metals (PGMs), spent catalysts demand recycling for both economic and environmental benefits. This article reviews the main pyrometallurgical processes for PGM recovery from spent catalysts. Existing processes, including smelting, vaporization, and sintering processes, are discussed based in part on a review of the physiochemical characteristics of PGMs in spent catalysts. The smelting technology, which produces a PGM-containing alloy, is significantly influenced by the addition of various collectors, such as lead, copper, iron, matte, or printed circuit board (PCB), considering their chemical affinities for PGMs. The vaporization process can recover PGMs in vapor form at low temperatures (250-700°C), but it suffers high corrosion and potential environmental and health risks as a result of involvement of the hazardous gases, mainly Cl2 and CO. The sintering process serves as a reforming means for recycling of the spent catalysts by in situ reduction of their oxidized PGMs components. Among these processes, the smelting process seems more promising although its overall performance can be further improved by seeking a suitable target-oriented collector and flux, together with proper pretreatment and process intensification using an external field.

  12. Effect study of the support in nickel and cobalt catalysts for obtaining hydrogen from ethanol steam reforming; Estudo do efeito do suporte em catalisadores de cobalto e niquel para obtencao de hidrogenio a partir da reforma a vapor do etanol

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Sirlane Gomes da

    2013-09-01

    A range of oxide-supported metal catalysts have been investigated for the steam reforming of ethanol for the production of hydrogen and subsequent application in fuel cells. The catalysts were synthesized by the co-precipitation and internal gelification methods using cobalt and nickel as active metals supported on aluminum, zirconium, lanthanum and cerium oxides. After prepared and calcined at 550 C Masculine-Ordinal-Indicator the solids were fully characterized by different techniques such as X-rays diffraction(DRX), energy-dispersive X-ray spectroscopy (EDS), scanning electron microscopy, nitrogen adsorption (B.E.T), temperature-programmed reduction in H2 (TPR-H2) and thermogravimetric analysis. The catalytic tests were performed in a monolithic quartz reactor and submitted to different thermodynamic conditions of steam reforming of ethanol at temperatures varying from 500 Masculine-Ordinal-Indicator C to 800 Masculine-Ordinal-Indicator C. The product gas streams from the reactor were analyzed by an on-line gas chromatograph. The cobalt/nickel catalyst supported on a ceria-lanthania mixture (Co{sub 10%} / Ni{sub 5%} - CeO{sub 2}La{sub 2}O{sub 3}) showed good catalytic performance in hydrogen selectivity reaching a concentration greater than 65%, when compared to other catalytic systems such as: Co{sub 10%} / Ni5% - CeO{sub 2}; Co{sub 10%} / Ni{sub 5%} - CeO{sub 2}ZrO{sub 2}; Co{sub 10%} / Ni{sub 5%} - ZrO{sub 2}; Co{sub 10%} / Ni{sub 5%} - La{sub 2}O{sub 3}; Co{sub 10%} / Ni{sub 5%} - CeO{sub 2}La{sub 2}O{sub 3}/K{sub 2%}; Co{sub 10}% / Ni{sub 5%} - CeO{sub 2}La{sub 2}O{sub 3} / Na{sub 2%}; Ni{sub 10%} / Co{sub 5%} - CeO{sub 2}La{sub 2}O{sub 3}; Co-Al{sub 2}O{sub 3} e Co-Al{sub 2}O{sub 3}CeO{sub 2}. (author)

  13. CH4三自热重整制合成气催化剂的制备与性能%Preparation and Performance of Catalysts for Tri -reforming of CH4 -CO2 to Synthesis Gas

    Institute of Scientific and Technical Information of China (English)

    薛茹君; 王庆超

    2013-01-01

    In order to improve activity and stability of catalyst being used in reaction of methane tri -reforming , Ni/LDHs was modified with rare earth (CeO2 , La2 O3 ).Ce (La)-doped Mg-Al layered double oxide support (LDO) was obtained through calcination at 500℃ from the corresponding Ce (La) -doped Mg -Al layered double hydroxides (LDHs), which was prepared by co -precipitation method.Then the active component nickel was loaded on Ce (La)-LDO by impregnation to reconstruct the Ni/LDHs precursor .After roasting, the NiO/Ce (La)-MgO-Al2 O3 catalyst was prepared from the precursor at last .The Ni, Mg, Al elements in the cata-lyst was analyzed via ICP-AES.The specific surface area of the catalyst was tested by the BET method .The phase of the catalyst was characterized by XRD .The active center of the catalyst was characterized via H 2 -TPR techniques.The catalytic performance of the catalysts for tri -reforming of CH4 -CO2 to Synthesis Gas were test-ed with the feed gas which composition was n (CH4 )∶n (CO2 )∶n (H2O )∶n (O2 ) =1∶0.5∶1.8∶0.1 under 750℃and 0.1MPa.The results show that the NiO component was distributed on the surface of NiO /Ce (La)-MgO-Al2 O3 catalyst, and the reduction temperature of NiO was decreased largely .The doping component CeO 2 (or La2 O3 ) within the catalyst could adjust catalytic activity in a certain extent , and could improve the resistance performance to coke deposit greatly .The catalytic activity is better when the mass fraction of Ni is10%, the mass ratio of Al, and Mg is 1.7.Under the condition of 750℃and 0.1MPa, the CH4 conversion rate is 92.3%, and CO2 conversion rate is 98.3%.After having reacted 100 h, the CH4 conversion rate of Ni/CeO2 (La2 O3 )-MgO-Al2 O3 catalyst still remains above 75%.%  以稀土氧化物(CeO2、La2 O3)为助剂对Ni/类水滑石催化剂进行改性,用于CH4三自热重整反应,旨在改善催化剂的活性和稳定性。以共沉淀法先制得铈(镧)掺杂的镁铝类水

  14. Montmorillonite supported Ni-Fe catalysts for hydrogen production from steam reforming of ethanol%Ni-Fe/蒙脱土催化剂催化乙醇水蒸气重整制氢的研究

    Institute of Scientific and Technical Information of China (English)

    李宝茹; 殷雪梅; 吴旭; 安霞; 谢鲜梅

    2016-01-01

    采用浸渍法制备了一系列Ni-Fe/蒙脱土( MMT)催化剂,并应用于乙醇水蒸气重整制氢反应( ESR)。采用X射线衍射( XRD)、N2吸附脱附分析和H2-程序升温还原( H2-TPR)表征手段对催化剂的物理化学性质、还原性能、碳沉积等进行了研究。结果表明,Ni-Fe/MMT催化剂中,Ni、Fe高度分散在载体MMT层间及表面,而且Fe的加入降低了Ni颗粒的粒径,增强了Ni2+与载体的相互作用力。以10Ni5Fe/MMT为催化剂,在反应温度为500℃、水醇比为3:1、空速为12 h-1,反应进行30 h后,乙醇转化率为100%,氢气选择性仍保持72%,副产物CO和CH4含量明显降低。这是因为催化助剂Fe的引入,一方面,提高了Ni的分散度,使得ESR低温活性较好;另一方面,减小了Ni颗粒粒径,小颗粒的Ni有利于抑制甲烷的生成,并且Fe的加入加强了甲烷重整和水煤气变换反应,提高产物中氢气的选择性。%Ni-Fe/montmorillonite ( MMT ) catalysts were prepared by impregnation method for hydrogen production via ethanol steam reforming. The catalysts were characterized by XRD, H2-TPR, and N2 adsorption-desorption . It was found that Ni-Fe bimetallic catalysts exhibited higher activities and stability than single metallic catalysts due to the well dispersed Ni-Fe, small nickel crystallites and stronger interaction between Ni2+ and carrier. The conversion and selectivity were affected by the ratio of Ni to Fe. The 10Ni5Fe/MMT catalyst showed the optimum catalytic performance, its ethanol conversion was 100%, the selectivity of hydrogen gas remained at 72%, and selectivity of CO and CH4 were significantly decreased at 500℃ during 30 h testing. This could be attributed to the promoter Fe, which improves the dispersion of Ni and results in a good ESR activity at low reaction temperature. Small Ni particles can suppress methane formation and Fe addition can enhance the methane reforming with water and water gas shift reaction, resulting in higher

  15. Analysis of catalyst loss of a semi-regenerative catalytic reformer and revamp%半再生重整装置催化剂跑损原因分析及改造

    Institute of Scientific and Technical Information of China (English)

    吴振华; 陈建祥; 卢秋旭

    2013-01-01

    The semi-regenerative catalytic reformer of SINOPEC Tahe Company experienced two catalyst runaways in 2005 and 2009. The runaways mainly occurred at the connections of scallop plate, scallop cylinder and center pipe, etc of reactor M and reactor IV. The main cause of catalyst runaway is inappropriate material selection. As the materials of reactor internals are different, the expansions of the internals are different. In the emergency shutdown and start-up, the axial expansion will damage the seal of cap of center pipe and catalyst will run away. The other cause of catalyst runaway is improper reactor construction. As the reactor M and reactor IV are centrifugal radial reactors (bottom in, top out) and the effluent flows from center pipe to scallop cylinder, the up-lifting pressure on scallop plate rises with increase of operating load of the unit and the seal catalysts between skirt scallop plates are easy to be carried over. The major measures taken are: the bolts on the arc segment of packing gland are tightened, the bolts of scallop plate in connection with 4 lifting eyes are removed, The tightening bolts on scallop plate on packing gland of center pipe cap are loosened to ensure that the center pipe can expand and contract freely; In addition, the inlet and outlet of reactor III and reactor IV are changed so that the fluid flows radially through scallop cylinder and catalyst bed and to the center pipe. After revamping of reactors, the catalyst loss potential of the unit has been eliminated, the unit capacity has been debottlenecked and the economic benefit of the plant has been improved.%2005年及2009年中国石油化工股份有限公司塔河分公司半再生重整装置两次发生催化剂跑损,催化剂跑损的主要部位是重整第三、第四反应器扇形板、扇形筒、中心筒等相连部位.跑剂的主要原因:一是选材不合理,由于反应器内构件材质不同,热膨胀量也不同,在装置紧急停、开工的过程中,造成

  16. Oxidation catalyst

    Science.gov (United States)

    Ceyer, Sylvia T.; Lahr, David L.

    2010-11-09

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

  17. High-performance core-shell PdPt@Pt/C catalysts via decorating PdPt alloy cores with Pt

    Science.gov (United States)

    Wu, Yan-Ni; Liao, Shi-Jun; Liang, Zhen-Xing; Yang, Li-Jun; Wang, Rong-Fang

    A core-shell structured low-Pt catalyst, PdPt@Pt/C, with high performance towards both methanol anodic oxidation and oxygen cathodic reduction, as well as in a single hydrogen/air fuel cell, is prepared by a novel two-step colloidal approach. For the anodic oxidation of methanol, the catalyst shows three times higher activity than commercial Tanaka 50 wt% Pt/C catalyst; furthermore, the ratio of forward current I f to backward current I b is high up to 1.04, whereas for general platinum catalysts the ratio is only ca. 0.70, indicating that this PdPt@Pt/C catalyst has high activity towards methanol anodic oxidation and good tolerance to the intermediates of methanol oxidation. The catalyst is characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The core-shell structure of the catalyst is revealed by XRD and TEM, and is also supported by underpotential deposition of hydrogen (UPDH). The high performance of the PdPt@Pt/C catalyst may make it a promising and competitive low-Pt catalyst for hydrogen fueled polymer electrolyte membrane fuel cell (PEMFC) or direct methanol fuel cell (DMFC) applications.

  18. Technical analysis of failure of catalyst support of reformer furnace tube of a hydrogen generation unit%制氢装置转化炉炉管催化剂支托失效分析

    Institute of Scientific and Technical Information of China (English)

    齐庆轩; 冯岩

    2012-01-01

    The damages of catalyst support of reformer furnace tubes of No. 1 hydrogen generation unit in SINOPEC Shijiazhuang Refining & Chemical Co. , Ltd. in two maintenances were introduced. The composition analysis of catalyst support, the study on the macroscopic photo, the analysis of damaged surface of catalyst support of Incoloy800H, the metallographic analysis, energy dispersion spectrum (EDS) analysis, and scanning electron microscope analysis of support' s section area as well as study on the anti-caburization performances of Cr25Ni20 and Incoloy800H materials have concluded the following: The damages of catalyst support was caused by surface carburization of catalyst support material under high temperature in the presence of hydrogen, which led to phase changes of material surface structure, material stratification, loosening and bulging of surface material structure, large amount of micro-crackings in grain boundary at surface area and eduction of large amount of carbides. All these will reduce the ductility and plasticity of material. Therefore, it is difficult for the catalyst support to restore its original state after thermal expansion, which explains why there are some bulges on the tube of failed support. The anti-carburization performance is greatly improved after application of Cr25Ni20 steel material.%对两次检修中所发现的中国石油化工股份有限公司石家庄炼化分公司l号制氢装置转化炉炉管催化剂支托出现损坏的情况做了介绍,并对两种批次的催化剂支托进行了成分分析,对使用Incoloy800H材料、损坏严重的催化剂支托表面宏观照片进行了分析,对损伤支托的横截面进行金相、电镜及能谱检验分析.通过对Cr25Ni20和lncoloy800H两种材料的抗渗碳能力的比较,得出了以下结论:催化剂支托损伤的原因是材料在含氢高温环境下发生了表面渗碳现象,直接导致材料表面组织相变、材料分层、表现材料组织疏松和隆起,

  19. 制备方法对Ni/ZnO催化丙三醇重整-氢解性能的影响%Reforming and Hydrogenolysis of Glycerol over Ni/ZnO Catalysts Prepared by Different Methods

    Institute of Scientific and Technical Information of China (English)

    胡基业; 刘晓钰; 王彬; 裴燕; 乔明华; 范康年

    2012-01-01

    The catalytic conversion of glycerol to 1,2-propanediol (1,2-PDO) is generally conducted batch-wise in an autoclave in the presence of high pressure H2. The reforming and hydrogenolysis of glycerol to 1,2-PDO over Ni/ZnO catalysts in a continuous flow fixed-bed reactor without added H2 was reported. The Ni/ZnO catalysts were prepared by wetness impregnation (WI), co-precipitation (CP), hydro-thermal treatment (HT), and carbon microsphere hard-templating (CT) methods. The catalysts were characterized by X-ray diffraction (XRD), temperature-programmed reduction (TPR), transmission electron microscopy (TEM), and H2 titration. At a low weight hourly space velocity (WHSV) of glycerol, the 1,2-PDO produced got degraded to ethanol and gas phase products over catalysts with high Ni dispersion, while at a high WHSV, the selectivity for 1,2-PDO was limited by the hydrogenation of the acetol intermediate. At the optimized WHSV, the catalyst with a higher Ni dispersion was more selective for 1,2-PDO, and over the Ni/ZnO catalyst with the highest Ni dispersion, the highest selectivity of 54.9% for 1,2-PDO was obtained at a glycerol conversion of 85.4% at the WHSV of 0.84 h-1.%采用浸渍法、共沉淀法、水热法和碳微球硬模板法制备了Ni/ZnO催化剂,运用X射线衍射、程序升温还原、透射电子显微镜和氢滴定等手段对其进行了表征,并用于连续固定床反应器中无外加氢气条件下的丙三醇重整-氢解反应.结果表明,在较低空速下,生成的1,2-丙二醇(1,2-PDO)易在Ni分散度较高的催化剂上进一步裂解为乙醇和气相产物;而在较高空速下,其选择性受制于中间产物丙酮醇的加氢.在优化的空速下,Ni分散度越高越有利于1,2-PDO的生成.在Ni分散度最高的Ni/ZnO催化剂上,当丙三醇质量空速为0.84h-1时,1,2-PDO选择性最高,为54.9%,丙三醇转化率为85.4%.

  20. Hydrogen evolution from aqueous-phase photocatalytic reforming of ethylene glycol over Pt/TiO2 catalysts: Role of Pt and product distribution

    Science.gov (United States)

    Li, Fuying; Gu, Quan; Niu, Yu; Wang, Renzhang; Tong, Yuecong; Zhu, Shuying; Zhang, Hualei; Zhang, Zizhong; Wang, Xuxu

    2017-01-01

    Pt nanoparticles were loaded on anatase TiO2 by the photodeposition method to investigate their photocatalytic activity for H2 evolution in an aqueous solution containing a certain amount of ethylene glycol (EG) as the sacrificial agent. The surface properties and chemical states of the Pt/TiO2 sample were characterized by X-ray powder diffraction analysis, Brunauer-Emmett-Teller surface area analysis, transmission electron microscopy, X-ray photoelectron spectroscopy, electron paramagnetic resonance, and electrochemical resistance. The aqueous-phase photocatalytic EG reforming using Pt/TiO2 and anatase TiO2 generated not only H2 and CO2, but also CO, CH4, C2H6, and C2H4. Moreover, the amount of formate and acetate complexes in the solution increased gradually. The EG adsorption and gas-phase intermediates during photocatalytic reaction processes were investigated by the in situ FTIR spectrum. Finally, the photocatalytic EG reforming reaction mechanism was elucidated. This helped to better understand the role of a sacrificial agent in a photocatalytic hydrogen production.

  1. Stoichiometric consideration of steam reforming of methane on Ni/Al{sub 2}O{sub 3} catalyst at 650{sup o}C by using a solar furnace simulator

    Energy Technology Data Exchange (ETDEWEB)

    Yokota, Osamu; Oku, Yoshinori; Sano, Taizo; Hasegawa, Noriko; Matsunami, Jun; Tsuji, Masamichi; Tamaura, Yutaka [Tokyo Institute of Technology (Japan). Research Center for Carbon Recycling and Utilization

    2000-01-01

    Stoichiometry of the steam reforming of methane (CH{sub 4} + H{sub 2}O = CO + 3H{sub 2}) was studied using a steam generator, which can keep the steam content in the reactant gases (methane and steam). The reactor was irradiated using the concentrated Xe-lamp beam (solar simulator) to 650{sup o}C . The mole ratio of H{sub 2}O/CH{sub 4} in the reactant gases was kept 1/1, and the Ni/Al{sub 2}O{sub 3} catalyst was used. The deposited C and unreacted H{sub 2}O amounts were calculated by the mass balance equations with the assumption that inlet gases of CH{sub 4} + H{sub 2}O produce outlet gases of CO, CO{sub 2}, H{sub 2}, CH{sub 4} and H{sub 2}O, and Carbon. The gaseous contents in the outlet gases from the reactor were estimated from the data of the gas chromatography. Those values and the calculated C and H{sub 2}O values were close to those of equilibrium condition theoretically evaluated using thermodynamic data at 650{sup o}C. The inlet gases controlled at the mole ratio of H{sub 2}O/CH{sub 4} = 1/l converted to CO and CO{sub 2} (CO/CO{sub 2} = 3/1) stoichiometrically on the Ni/Al{sub 2}O{sub 3} catalyst at 650{sup o}C. (author)

  2. 通过Au修饰提高质子交换膜燃料电池PtCo合金催化剂稳定性%Improved Stability of PtCo Alloy Catalysts for Proton Exchange Membrane Fuel Cells by Gold Decoration

    Institute of Scientific and Technical Information of China (English)

    陈磊; 齐意; 木士春

    2015-01-01

    目的:解决质子交换膜燃料电池贵金属催化剂利用率低、电化学稳定性差的问题,从而堆动其产业化进程。方法通过湿化学共沉积法获得低Pt特征的PtCo合金催化剂,采用欠电位沉积方法制备Au修饰的PtCo合金催化剂,应用原子吸收光谱和电化学循环伏安加速测试技术研究Au修饰PtCo合金催化剂的电化学稳定性。结果成功制备了Au修饰的PtCo合金催化剂。 Au修饰后,PtCo合金催化剂的氧还原反应性能几乎没有改变,但Co的溶蚀率得到降低,而且电化学稳定性也得到提高。结论通过采用Au等具有高电化学腐蚀电位的金属修饰Pt合金催化剂,以提高催化剂电化学稳定性的研究思路是可行的。%ABSTRACT:Objective To facilitate the commercialization of proton exchange membrane fuel cells by revolving the key issues in-cluding low utilization and deteriorated stability of noble metal catalysts. Methods After preparation of PtCo alloy catalysts with low Pt loading by a chemical co-deposition method, the gold decorated PtCo alloy catalyst was prepared in terms of an under-potential-deposition method, and then the electrochemical stability of the gold-decorated PtCo alloy catalyst was characterized by atomic ab-sorption spectroscopy and electrochemical accelerated test technique. Results Au-decorated PtCo alloy catalyst was successfully prepared. After decoration of gold, the oxygen reduction reaction activity of PtCo alloy catalysts remained unchanged, and the ero-sion rate of Co element for PtCo alloy catalysts in electrolyte solutions decreased with an improved electrochemical stability. Con-clusion It was feasible to improve the stability of PtCo alloy catalysts by decoration with metals possessing a high corrosion potential such as Au.

  3. Intermediate-temperature solid oxide fuel cell employing reformed effective biogas: Power generation and inhibition of carbon deposition

    Science.gov (United States)

    Miyake, Michihiro; Iwami, Makoto; Goto, Kenta; Iwamoto, Kazuhito; Morimoto, Koki; Shiraishi, Makoto; Takatori, Kenji; Takeuchi, Mizue; Nishimoto, Shunsuke; Kameshima, Yoshikazu

    2017-02-01

    A power generation system consisting of an intermediate-temperature solid oxide fuel cell (IT-SOFC) and an external reformer for biogas is developed, and its performance is investigated for advanced use of effective biogas. The IT-SOFC is fueled with syngas produced via biogas reforming, and is successfully operated at 600 and 700 °C using Ni0.8Cu0.2 alloy/gadolinia-doped ceria electrolyte (Ni0.8Cu0.2/GDC) cermet anodes and a LaAlO3 supported-Ni (Ni/LaAlO3) catalyst. The Ni/LaAlO3 catalyst stably exhibits high reforming performance for effective biogas at 800 °C for 27 h, and carbon deposition on the catalyst is prevented. The electrochemical performance of the Ni0.8Cu0.2/GDC cermet anode using syngas fuel possessing a H2:CO ratio of approximately 3:1 is comparable to the performance achieved with H2 fuel; the anode remains stable after 24 h of operation at 700 °C without interruption and is unaffected by carbon deposition.

  4. Preparation of syngas via steam reforming of glycerol over modified Ni/LTA catalysts%改良的5A分子筛载Ni催化剂上甘油水蒸汽重整制合成气

    Institute of Scientific and Technical Information of China (English)

    黄遵谕; 徐成华; 李钰春; 雷亚聪; 肖惠文; 张永祥; 陈军

    2012-01-01

    以Linde型5A分子筛(LTA)为载体,采用浸渍法制备了金属氧化物修饰的负载型Ni基催化剂,并用于甘油水蒸汽重整制合成气.催化剂表征及催化稳定性的考察结果表明Mo、La、Ca氧化物的同时修饰可抑制Ni/LTA催化剂中活性组分Ni与载体LTA的相互作用,在甘油重整反应中具有较好的稳定性能.反应工艺考察结果表明,NiMoLaCa/LTA在反应温度600℃、原料液中甘油/水的体积比3∶7、LHSV为2.67h-1的条件下,甘油重整反应产物气有理想的n(H2)/n(CO)比2.06;升高反应温度、降低甘油/水体积比和减小LHSV均可提高甘油的产气率,但会加快CO的水气变换反应;CO和CO2的甲烷化反应受反应温度的影响较大.%Ni based catalysts supported on Linde type 5A molecular sieves (LTA) modified by metal oxides were prepared by impregnation, and used for catalyzing glycerol steam reforming (GSR) to syngas. The results of the characterization and catalytic stability tests of the catalysts showed that the co-modification with Mo, La and Ca oxides could weaken the stronger interaction between active species Ni and support LTA in Ni/LTA catalysts, which improved the catalytic stability of NiMoLaCa/LTA in GSR. The effects of reaction parameters on GSR reaction over NiMoLaCa/LTA were investigated, and the results showed that under the conditions of temperature of 600℃, volume ratio of glyeerol to water of 3:7 and LHSV of 2.67h-1, the produced gaseous product had a ideal HVCO molar ratio of 2.06; a higher temperature, lower glycerol/water volume ratio and LHSV were helpful to improve GSR reaction and CO water-gas shift reaction; and the reactions of CO and CO2 methanation were obviously related to temperature.

  5. La-Sr-Ni-Co-O based perovskite-type solid solutions as catalyst precursors in the CO 2 reforming of methane

    Science.gov (United States)

    Valderrama, Gustavo; Kiennemann, Alain; Goldwasser, Mireya R.

    La 1- xSr xNi 0.4Co 0.6O 3 and La 0.8Sr 0.2Ni 1- yCo yO 3 solid solutions with perovskite-type structure were synthesized by the sol-gel resin method and used as catalytic precursors in the dry reforming of methane with CO 2 to syngas, between 873 and 1073 K at atmospheric pressure under continuous flow of reactant gases with CH 4/CO 2 = 1 ratio. These quaternary oxides were characterized by X-ray diffraction (XRD), BET specific surface area and temperature-programmed reduction (TPR) techniques. XRD analyses of the more intense diffraction peaks and cell parameter measurements showed formation of La-Sr-Ni-Co-O solid solutions with La 0.9Sr 0.1CoO 3 and/or La 0.9Sr 0.1NiO 3 as the main crystallographic phases present on the solids depending on the degree of substitution. TPR analyses showed that Sr doping decreases the temperature of reduction via formation of intermediary species producing Ni 0, Co 0 with particle sizes in the range of nanometers over the SrO and La 2O 3 phases. These metallic nano particles highly dispersed in the solid matrix are responsible for the high activity shown during the reaction and avoid carbon formation. The presence of Sr in doping quantities also promotes the secondary reactions of carbon formation and water-gas shift in a very small extension during the dry reforming reaction.

  6. La-Sr-Ni-Co-O based perovskite-type solid solutions as catalyst precursors in the CO{sub 2} reforming of methane

    Energy Technology Data Exchange (ETDEWEB)

    Valderrama, Gustavo [Laboratorio de Catalisis, Petroleo y Petroquimica, Unidad de Estudios Basicos, Universidad de Oriente - Nucleo Bolivar, La Sabanita - Calle San Simon, Estado Bolivar 8001 (Venezuela); Kiennemann, Alain [Laboratoire des Materiaux et Procedes pour la Catalyse, UMR 7515, ECPM, Universite Louis Pasteur, 25 rue Becquerel, 67087 Strasbourg Cedex 2 (France); Goldwasser, Mireya R. [Centro de Catalisis, Petroleo y Petroquimica, Facultad de Ciencias - Universidad Central de Venezuela. Paseo los Ilustres, Los Chaguaramos, Caracas 1040 (Venezuela)

    2010-04-02

    La{sub 1-x}Sr{sub x}Ni{sub 0.4}Co{sub 0.6}O{sub 3} and La{sub 0.8}Sr{sub 0.2}Ni{sub 1-y}Co{sub y}O{sub 3} solid solutions with perovskite-type structure were synthesized by the sol-gel resin method and used as catalytic precursors in the dry reforming of methane with CO{sub 2} to syngas, between 873 and 1073 K at atmospheric pressure under continuous flow of reactant gases with CH{sub 4}/CO{sub 2} = 1 ratio. These quaternary oxides were characterized by X-ray diffraction (XRD), BET specific surface area and temperature-programmed reduction (TPR) techniques. XRD analyses of the more intense diffraction peaks and cell parameter measurements showed formation of La-Sr-Ni-Co-O solid solutions with La{sub 0.9}Sr{sub 0.1}CoO{sub 3} and/or La{sub 0.9}Sr{sub 0.1}NiO{sub 3} as the main crystallographic phases present on the solids depending on the degree of substitution. TPR analyses showed that Sr doping decreases the temperature of reduction via formation of intermediary species producing Ni{sup 0}, Co{sup 0} with particle sizes in the range of nanometers over the SrO and La{sub 2}O{sub 3} phases. These metallic nano particles highly dispersed in the solid matrix are responsible for the high activity shown during the reaction and avoid carbon formation. The presence of Sr in doping quantities also promotes the secondary reactions of carbon formation and water-gas shift in a very small extension during the dry reforming reaction. (author)

  7. Ni/CeO{sub 2}-Al{sub 2}O{sub 3} catalysts promoted with noble metals for the hydrogen production by ethanol vapor reforming; Catalisadores de Ni/CeO{sub 2}-Al{sub 2}O{sub 3} promovidos com metais nobres para a producao de hidrogenio por reforma a vapor de etanol

    Energy Technology Data Exchange (ETDEWEB)

    Profeti, Luciene P.R.; Ticianelli, Edson Antonio; Assaf, Elisabete Moreira [Universidade de Sao Paulo (IQSC/USP), Sao Carlos, SP (Brazil). Inst. de Quimica]. E-mail: eassaf@iqsc.usp.br

    2008-07-01

    The catalytic activity of Ni/CeO{sub 2}-Al{sub 2}O{sub 3} catalysts modified with noble metals (Ru, Ir, Pt and Pd) was investigated in the steam reforming of ethanol. The catalysts were characterized by energy dispersive spectroscopy, X-ray diffraction, UV-Vis diffuse reflectance spectroscopy and H{sub 2} temperature-programmed reduction-X-ray absorption fine structure (XANES). The results showed that the formation of inactive nickel aluminate was avoided due to the presence of a CeO{sub 2} dispersed on the alumina. The promoting effect of noble metals included a decrease of the reduction temperatures of NiO species interacting with the support due to the hydrogen spillover effect, leading to an increase of the reducibilities of the promoted catalysts The better catalytic performance for the ethanol steam reforming was obtained for the NiPd/CeAl catalyst, which presented an effluent gaseous mixture with the highest H{sub 2} yield. (author)

  8. Estudo microestrutural do catalisador Ni/gama-Al2O3: efeito da adição de CeO2 na reforma do metano com dióxido de carbono Microstructural study of Ni/gamma-Al2O3 catalyst: addition effects of CeO2 on carbon dioxide reforming of methane

    Directory of Open Access Journals (Sweden)

    Antoninho Valentini

    2003-10-01

    Full Text Available The carbon dioxide reforming of methane was carried out over nickel catalysts supported on the gamma-Al2O3/CeO2 system prepared by wet impregnation. With the increase of the CeO2 weight in the catalyst, a higher stability was observed in the catalytic activity, together with an excellent resistance to carbon deposition and a better Ni dispersion. The catalysts were characterized by means of surface area measurements, TPR, H2 chemisorption, XRD, SEM, EDX, XPS and TEM. An interaction between Ni and CeO2 was observed to the Ni/CeO2 sample after activation in a H2 atmosphere above 300 ºC. Such behavior has a significantly influence on the catalytic activity.

  9. Microstructural study of Ni/{gamma}-Al{sub 2}O{sub 3} catalyst: addition effects of CeO{sub 2} on carbon dioxide reforming of methane; Estudo microestrutural do catalisador Ni/{gamma}-Al{sub 2}O{sub 3} - efeito da adicao de CeO{sub 2} na reforma do metano com dioxido de carbono

    Energy Technology Data Exchange (ETDEWEB)

    Valentini, Antoninho; Probst, Luiz Fernando Dias [Santa Catarina Univ., Florianopolis, SC (Brazil). Dept. de Quimica; Carreno, Neftali L. V.; Leite, Edson R.; Pontes, Fenelon M.; Longo, Elson [Sao Carlos Univ., SP (Brazil). Dept. de Quimica]. E-mail: derl@power.ufscar.br; Schreiner, Wido H.; Lisboa-Filho, Paulo N. [Parana Univ., Curitiba, PR (Brazil). Dept. de Fisica

    2003-10-01

    The carbon dioxide reforming of methane was carried out over nickel catalysts supported on the {gamma}-Al{sub 2}O{sub 3}/CeO{sub 2} system prepared by wet impregnation. With the increase of the Co2 weight in the catalyst, a higher stability was observed in the catalytic activity, together with an excellent resistance to carbon deposition and a better Ni dispersion. The catalysts were characterized by means of surface area measurements, TPR, H{sub 2} chemisorption, XRD, SEM, EDX, XPS and TEM. An interaction between Ni and CeO{sub 2} was observed to the Ni/CeO{sub 2} sample after activation in a H{sub 2} atmosphere above 300 deg C. Such behavior has a significantly influence on the catalytic activity. (author)

  10. Development of the Ni/Al{sub 2}O{sub 3}/ZrO{sub 2} catalyst to steam reforming of the natural gas process; Desenvolvimento do catalisador Ni/Al2O3/ZrO2 para o processo de reforma do gas natural

    Energy Technology Data Exchange (ETDEWEB)

    Neiva, Laedna Souto; Ramalho, Melanea A.F.; Costa, Ana Cristina Figueiredo de Melo; Gama, Lucianna [Universidade Federal de Campina Grande (UFCG), PB (Brazil); Andrade, Heloysa M.C. [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil); Kiminami, Ruth Herta G.A. [Universidade Federal de Sao Carlos (UFSCAR), SP (Brazil)

    2008-07-01

    The aim of this work is to develop catalyst of the type Ni/{alpha}-Al{sub 2}O{sub 3} modified with 0.005 mol of ZrO{sub 2} and structural, morphologic and catalytic characterizations, aiming employ in the reforming process of the natural gas. The catalytic supports were obtained by synthesis method for combustion reaction according to the concepts of the propellants chemistry. The active species of the catalyst (nickel) was deposited over the support by humid impregnation method. The catalytic supports were characterized by XRD, morphologic analysis by SEM and TEM, textural analysis by BET method before and after of the impregnation with nickel and were done catalytic tests in laboratory. The catalytic supports shows structure without any secondary phase with crystallinity elevated degree and crystal size varying between 5.7 and 7.0 nm. The catalytic test shows that these catalysts promoted a conversion percentile considerable of the natural gas in syngas. (author)

  11. SYNGAS PRODUCTION FROM CO2-REFORMING OF CH4 OVER SOL-GEL SYNTHESIZED Ni-Co/Al2O3-MgO-ZrO2 NANOCATALYST: EFFECT OF ZrO2 PRECURSOR ON CATALYST PROPERTIES AND PERFORMANCE

    Directory of Open Access Journals (Sweden)

    Seyed Mehdi Sajjadi

    2015-05-01

    Full Text Available Ni-Co/Al2O3-MgO-ZrO2 nanocatalyst with utilization of two different zirconia precursors, namely, zirconyl nitrate hydrate (ZNH and zirconyl nitrate solution (ZNS, was synthesized via the sol-gel method. The physiochemical properties of nanocatalysts were characterized by XRD, FESEM, EDX, BET and FTIR analyses and employed for syngas production from CO2-reforming of CH4. XRD patterns, exhibiting proper crystalline structure and homogeneous dispersion of active phase for the nanocatalyst ZNS precursor employed (NCAMZ-ZNS. FESEM and BET results of NCAMZ-ZNS presented more uniform morphology and smaller particle size and consequently higher surface areas. In addition, average particle size of NCAMZ-ZNS was 15.7 nm, which is close to the critical size for Ni-Co catalysts to avoid carbon formation. Moreover, FESEM analysis indicated both prepared samples were nanoscale. EDX analysis confirmed the existence of various elements used and also supported the statements made in the XRD and FESEM analyses regarding dispersion. Based on the excellent physiochemical properties, NCAMZ-ZNS exhibited the best reactant conversion across all of the evaluated temperatures, e.g. CH4 and CO2 conversions were 97.2 and 99% at 850 ºC, respectively. Furthermore, NCAMZ-ZNS demonstrated a stable yield with H2/CO close to unit value during the 1440 min stability test.

  12. The role of Pt and Pd in enhancing the conversion of sorbitol to hydrogen over supported Ni-Pt and Ni-Pd catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Tanksale, A.; Lu, G.Q. [Queensland Univ., Brisbane (Australia); Beltramini, J.N. [Queensland Univ., Brisbane (Australia). ARC Centre of Excellence for Functional Nanomaterials

    2009-07-01

    This study investigated the enhanced activity of bimetallic nickel-platinum (Ni-Pt) and nickel-palladium (Ni-Pd) catalysts for the production of hydrogen from reformed biomass-based products. The catalysts were prepared on an aluminum oxide (Al203) nanofibre. Mesoporous zirconia and composite silica-zirconia-ceria were used to determine the role of noble metals and supports. Desorption, oxidation, and temperature programmed reduction studies were conducted to investigate metal-metal and metal-support interactions. The study showed that Pt and Pd additions increased the reducibility of Ni catalysts. The bimetallic catalysts exhibited rates of hydrogen production 6 times higher than rates observed in pure metal catalysts. Sorbitol conversion increased from 35 per cent for the Ni catalyst to 62 per cent for the Ni-Pt catalyst. It was concluded that the alloying effect of the Ni-Pt and Ni-Pd systems lowered the carbon monoxide (CO) adsorption heat, and facilitated removal of the adsorbed CO by the water gas shift reaction.

  13. Modeling Open-Flow Steam Reforming of Methanol over Cu/ZnO/Al2O3 Catalyst in an Axisymmetric Reactor

    Directory of Open Access Journals (Sweden)

    Leonardo Pacheco

    2015-01-01

    Full Text Available This paper describes a CFD study of the steam-reforming process (SRP of methanol in a short pseudo-contact time reactor of fixed bed type, in axi-symmetric conditions. The SRP is important sake for hydrogen production, and the design /scale-up/control of the industrial processes in the future are supported by a reliable knowledge and prediction of the catalytic reaction. The difficulty of determining the reaction scheme and the associated constants is wellknown, due to the necessity of identifying the reaction kinetics in purely chemical regime, meaning with a perfect homogeneity and flow independence. Practically these ideal conditions, albeit assumed, are not fulfilled so that the intrinsic chemical kinetics is not reached. For the case of SRP, we have attempted here to validate the Peppley’s model by a numerical modelling reproducing exactly the local conditions in the experimental duct, accounting for gradients in the cross section. The numerical results show the same trends than the experimental one, but with a slight shift of 20% as a consequence of the reactor heterogeneity. This result seems acceptable to validate the use of the Peepley’s model for further studies in other types of complex flow reactors.

  14. Dry Reforming of Methane Over Various Doping Level of Ce on La1-Xcexni0.4Fe0.6O3perovskite nano catalyst

    Directory of Open Access Journals (Sweden)

    Parastoo Dezvareh

    2016-10-01

    Full Text Available The La1-xCexNi0.4Fe0.6O3 (x= 0.1, 0.2 and 0.3 perovskite nanostructures were prepared via citrate sol-gel method. Synthesized samples were characterized by X-ray diffraction (XRD, temperature programmed reduction (TPR, and inductively coupled plasma (ICP techniques. Specific surface area was determined by BET measurement. Scanning and transmission electron microscopy techniques were applied to study the morphology of the prepared samples. XRD patterns confirmed that a well-crystallized perovskite structure was formed in doping level up to x=0.2. Morphology results showed that homogenous particles in the range of nanometers were obtained through the applied synthesis method. TPR analysis revealed that by increasing the doping level of Ce up to 0.2 inthe preparedsamples, reduction process shifted to lower temperatures.The addition of Ce to La1-xCexNi0.4Fe0.6O3enhances the catalytic activity up to x= 0.2,but decreased significantly when x> 0.2. Catalytic activityof La1-xCexNi0.4Fe0.6O3perovskites in dry reforming of methane (DRM were: LaNiO3>La0.8Ce0.2Ni0.4Fe0.6O3>La0.9Ce0.1Ni0.4Fe0.6O3> LaNi0.4Fe0.6O3>La0.7Ce0.3Ni0.4Fe0.6O3

  15. Catalysts with Cu base supported in mixed oxides to generate H{sub 2}: reformed of methanol in oxidant atmosphere; Catalizadores a base de Cu soportado en oxidos mixtos para generar H{sub 2}: Reformado de metanol en atmosfera oxidante

    Energy Technology Data Exchange (ETDEWEB)

    Aguila M, M.M.; Perez H, R. [ININ, Carr. Mexico-Toluca S/N LaMarquesa, Ocoyoacac, Edo. de Mexico C. P. 52750 (Mexico); Rodriguez L, V. [Centro Universitario de Vinculacion-BUAP, Puebla (Mexico)]. e-mail: pehr@nuclear.inin.mx

    2006-07-01

    In this work, the characterization of Cu supported in CeO{sub 2}-ZrO{sub 2}, for to generate H{sub 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{sub 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{sub 2}/ZrO{sub 2} relationship. The morphology of the catalysts was analyzed by SEM being observed semispheric particles for the rich materials in ZrO{sub 2} and added planars in the rich materials in CeO{sub 2}. The ceria addition to the zircon favors the specific area of the mixed oxides CeO{sub 2}-ZrO{sub 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{sub 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)

  16. Catalyst and process development for hydrogen preparation from future fuel cell feedstocks. Quarterly report, April 1-June 30, 1980. [Pt/Pd

    Energy Technology Data Exchange (ETDEWEB)

    Yarrington, R M; Feins, I R; Hwang, H S

    1980-07-01

    Phase II of the contract, which involved catalyst preparation and evaluation, was nearly completed this quarter. Phase III, which calls for the design and construction of a fuel processor, was started. During the quarter, four types of tests were run on the small scale catalyst screening unit. The operating line for coke-free operations was found to be approximately between 0.41 to 0.44 O/sub 2//C level. Screening at lower O/sub 2//C levels led to problems with plugging. In other tests, increased severity for screening steam reforming catalysts was obtained by doubling the space velocity. Another series of tests were run to determine the gas composition from the catalytic partial oxidation (CPO) section and to evaluate two CPO catalysts. In the other series of tests, catalysts were aged for about 20 hours using a propane, steam, and air mixture before testing with No. 2 oil for another five hours. This latter test has been used to study Pt/Rh catalysts made with various supports. Differences were readily determined for Pt/Rh supported on alpha alumina and Pt/Rh supported on stabilized alumina. This test method will find continued use in evaluating metal-support interactions. Several samples must be evaluated by this method before aging runs are made in the larger unit. After leaching alumina from a used Pt/Rh catalyst, the x-ray diffraction pattern showed the presence of a Pt-Rh alloy in the metal residue. Experiments were run to show that the alloy was formed in the reactor during testing and not during catalyst preparation. A larger version of the ATR reactor has been designed and major components are on order. Completion of the construction phase is scheduled for the next quarter.

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

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

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

  18. Development of GREET Catalyst Module

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhichao [Argonne National Lab. (ANL), Argonne, IL (United States). Energy Systems Division; Dunn, Jennifer B. [Argonne National Lab. (ANL), Argonne, IL (United States). Energy Systems Division; Cronauer, Donald C. [Argonne National Lab. (ANL), Argonne, IL (United States). Energy Systems Division

    2014-09-01

    Catalysts are critical inputs for many pathways that convert biomass into biofuels. Energy consumption and greenhouse gas (GHG) emissions during the production of catalysts and chemical inputs influence the life-cycle energy consumption, and GHG emissions of biofuels and need to be considered in biofuel life-cycle analysis (LCA). In this report, we develop energy and material flows for the production of three different catalysts (tar reforming, alcohol synthesis, Zeolite Socony Mobil-5 [ZSM-5]) and two chemicals (olivine, dimethyl ether of polyethylene glycol [DEPG]). These compounds and catalysts are now included in the Greenhouse Gases, Regulated Emissions and Energy Use in Transportation (GREET™) catalyst module. They were selected because they are consumed in existing U.S. Department of Energy (DOE) analyses of biofuel processes. For example, a thermochemical ethanol production pathway (indirect gasification and mixed alcohol synthesis) developed by the National Renewable Energy Laboratory (NREL) uses olivine, DEPG, and tar reforming and alcohol synthesis catalysts (Dutta et al., 2011). ZSM-5 can be used in biofuel production pathways such as catalytic upgrading of sugars into hydrocarbons (Biddy and Jones, 2013). Other uses for these compounds and catalysts are certainly possible. In this report, we document the data sources and methodology we used to develop material and energy flows for the catalysts and compounds in the GREET catalyst module. In Section 2 we focus on compounds used in the model Dutta et al. (2011) developed. In Section 3, we report material and energy flows associated with ZSM-5 production. Finally, in Section 4, we report results.

  19. Supported bimetallic nano-alloys as highly active catalysts for the one-pot tandem synthesis of imines and secondary amines from nitrobenzene and alcohols

    NARCIS (Netherlands)

    Meenakshisundaram, Sankar; He, Qian; Dawson, Simon; Nowicka, Ewa; Lu, Li; Bruijnincx, Pieter C. A.; Beale, Andrew M.; Kiely, Christopher J.; Weckhuysen, Bert M.

    2016-01-01

    The synthesis and functionalization of imines and amines are key steps in the preparation of many fine chemicals and for pharmaceuticals in particular. Traditionally, metal complexes are used as homogeneous catalysts for these organic transformations. Here we report gold-palladium and ruthenium-pall

  20. Methanol partial oxidation reformer

    Science.gov (United States)

    Ahmed, Shabbir; Kumar, Romesh; Krumpelt, Michael

    1999-01-01

    A partial oxidation reformer comprising a longitudinally extending chamber having a methanol, water and an air inlet and an outlet. An igniter mechanism is near the inlets for igniting a mixture of methanol and air, while a partial oxidation catalyst in the chamber is spaced from the inlets and converts methanol and oxygen to carbon dioxide and hydrogen. Controlling the oxygen to methanol mole ratio provides continuous slightly exothermic partial oxidation reactions of methanol and air producing hydrogen gas. The liquid is preferably injected in droplets having diameters less than 100 micrometers. The reformer is useful in a propulsion system for a vehicle which supplies a hydrogen-containing gas to the negative electrode of a fuel cell.

  1. Developments of Catalysts for Hydrogen Production from Dimethyl Ether

    Institute of Scientific and Technical Information of China (English)

    Kaoru; Takeishi

    2007-01-01

    1 Results Dimethyl ether (DME) is expected as a clean fuel of the 21st century.I have developed new catalysts for hydrogen production by steam reforming of DME.Cu-Zn/Al2O3 catalysts prepared by the sol-gel method produce large quantities of H2 and CO2 by DME steam reforming under lower reaction temperature[1].However,the sol-gel catalysts will be more expensive than general catalysts prepared by impregnation methods and coprecipitation methods,because the precursor,alkoxides are very expensive.For pract...

  2. 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

    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. He...

  3. 直接内重整熔融碳酸盐燃料电池中甲烷蒸汽重整催化剂探索性研究%Pilot Study on the Use of Methane Steam Reforming Catalyst in Molten Carbonate Fuel Cell

    Institute of Scientific and Technical Information of China (English)

    李广龙; 周利; 王英旭; 王鹏杰; 林化新; 朱秀玲; 邵志刚

    2011-01-01

    选择甲烷蒸汽重整催化剂用于直接内重整熔融碳酸盐燃料电池(DIR-MCFC)中,并考察了DIR-MCFC的性能,讨论了电池放电量、气体压力、燃料气进料水/碳比(S/C)等因素对该催化剂性能的影响.结果表明,重整催化剂能够满足电池放电需求;放电量大小影响电池内的H2含量,但对CH4含量影响不大;当气体压力为0.36MPa时,电池内的H2含量最大;S/C越低,电池性能越高,相同放电量下,S/C=1时的电池电压比S/C=2时的高.%A methane steam reforming catalyst was selected by the comparison of its catalytic properties and resistance to carbon deposition. The performance of a molten carbon fuel cell (MCFC) using this catalyst was studied. The effect of discharge magnitude, gas pressure,and steam-carbon ratio (S/C) on the catalyst was also investigated. The results indicated that the catalyst could make the cell perform well,and the increment of the current affected the content of H2 in the cell. but it had minor effect on the content of CH4. In addition, the reforming reaction depended on the gas pressure. There was a maximal content of H2 in the cell at 0.36 MPa. With the decrease of S/C, the performance of MCFC was improved.

  4. Ternary Pt9RhFex Nanoscale Alloys as Highly Efficient Catalysts with Enhanced Activity and Excellent CO-Poisoning Tolerance for Ethanol Oxidation.

    Science.gov (United States)

    Wang, Peng; Yin, Shibin; Wen, Ying; Tian, Zhiqun; Wang, Ningzhang; Key, Julian; Wang, Shuangbao; Shen, Pei Kang

    2017-03-22

    To address the problems of high cost and poor stability of anode catalysts in direct ethanol fuel cells (DEFCs), ternary nanoparticles Pt9RhFex (x = 1, 3, 5, 7, and 9) supported on carbon powders (XC-72R) have been synthesized via a facile method involving reduction by sodium borohydride followed by thermal annealing in N2 at ambient pressure. The catalysts are physically characterized by X-ray diffraction, scanning transmission electron microscopy, and X-ray photoelectron spectroscopy, and their catalytic performance for the ethanol oxidation reaction (EOR) is evaluated by cyclic and linear scan voltammetry, CO-stripping voltammograms, and chronopotentiometry. All the Pt9RhFex/C catalysts of different atomic ratios produce high EOR catalytic activity. The catalyst of atomic ratio composition 9:1:3 (Pt/Rh/Fe) has the highest activity and excellent CO-poisoning tolerance. Moreover, the enhanced EOR catalytic activity on Pt9RhFe3/C when compared to Pt9Rh/C, Pt3Fe/C, and Pt/C clearly demonstrates the presence of Fe improves catalytic performance. Notably, the onset potential for CO oxidation on Pt9RhFe3/C (0.271 V) is ∼55, 75, and 191 mV more negative than on Pt9Rh/C (0.326 V), Pt3Fe/C (0.346 V), and Pt/C (0.462 V), respectively, which implies the presence of Fe atoms dramatically improves CO-poisoning tolerance. Meanwhile, compared to the commercial PtRu/C catalyst, the peak potential on Pt9RhFe3/C for CO oxidation was just slightly changed after several thousand cycles, which shows high stability against the potential cycling. The possible mechanism by which Fe and Rh atoms facilitate the observed enhanced performance is also considered herein, and we conclude Pt9RhFe3/C offers a promising anode catalyst for direct ethanol fuel cells.

  5. Upgrading of reformate gas for different applications with focus on small-scale hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Jannasch, Anna-Karin; Silversand, Fredrik [CATATOR AB, Lund (Sweden)

    2004-12-01

    Hydrogen gas or hydrogen rich gas is today used in many different applications, i.e. as fuel in fuel cells or additive in vehicle fuel (i.e. hythane) and as reagent or reducing agent in different industrial product lines. The majority of the hydrogen is produced either via electrolysis or reformation, where this work has entirely been focused on the latter alternative. The overarching aims of this project have been to demonstrate the need for reformate purification for different applications, and then, to investigate different available methods that can be used in order to enable the requested gas clean-up. The different purification methods have been examined with respect to parameters such as operating conditions (temperature, pressure), impurity tolerance, size, weight and cost. Another goal of the project has been to investigate how the reformer fuel type used influences the reformate gas quality and hence, the need for gas purification before the reformate can be fed to e.g. a low temperature polymer membrane fuel cell (PEMFC). For this reason, some experimental work has been performed. First, analysis of the reformate gas composition when natural gas, LPG, gasoline, diesel, kerosene (low and high S-concentration (i.e. JP8)) and ethanol have been processed. The reformation tests were carried out in a small scale reformer unit ({approx} 1 kW H{sub 2}) including Catator's catalyst formulations developed for the steam reforming, the water gas shift and the preferential oxidation reaction, respectively. Verification tests, with synthetic gas blends, including different potential reformate impurities, and with real reformate gas were thereafter performed with a commercial 4-cell PEMFC stack (3-5 W). Finally, some examination and also to some extent further development of Catator's existing gas purification units were made, i.e. chemical (WGS, PROX) and physical (regenerative adsorption). The Pd-alloy membrane seems to be the obvious choice of purification

  6. Catalyst and electrode research for phosphoric acid fuel cells

    Science.gov (United States)

    Antoine, A. C.; King, R. B.

    1987-01-01

    An account is given of the development status of phosphoric acid fuel cells' high performance catalyst and electrode materials. Binary alloys have been identified which outperform the baseline platinum catalyst; it has also become apparent that pressurized operation is required to reach the desired efficiencies, calling in turn for the use of graphitized carbon blacks in the role of catalyst supports. Efforts to improve cell performance and reduce catalyst costs have led to the investigation of a class of organometallic cathode catalysts represented by the tetraazaannulenes, and a mixed catalyst which is a mixture of carbons catalyzed with an organometallic and a noble metal.

  7. Desempenho de um reator integral de reforma a vapor de metano recheado com um catalisador industrial = Performance of an integral methane reforming fixed bed reactor packed with an industrial catalyst

    Directory of Open Access Journals (Sweden)

    Douglas Rodrigues Francisquini

    2005-07-01

    Full Text Available O presente trabalho tem por objetivo avaliar a atividade catalítica e o perfil de temperaturas num reator integral de reforma a vapor de metano, aquecido por forno elétrico e recheado com um catalisador industrial. Foram efetuadas medidas de temperatura no leito em nove posições axiais distintas e a composição dos produtos da reação foram determinadas por cromatografia. Os ensaios foram conduzidos com o forno a 500, 600 e 700ºC, razão molar de alimentação [H2O/CH4 ] = 4 e densidade fluxo-mássico de 0,2 e 0,5 kg/m2.s. Os resultados indicam que a utilização dos nove pontos foi suficiente para representar o comportamento térmico do reator e evidenciam a existência de perdas decalor significativas nas extremidades do reator. Tanto a atividade catalítica como a conversão apresentam-se sensíveis à temperatura operacional, entretanto, a temperatura do leito é praticamente insensível à vazão nas condições experimentais exploradas.The present work has the objective to evaluate the catalytic activity and the temperature profile inside an integral steam reforming fixed bed reactor heated by an electrical furnace and packed with an industrial catalyst. Nine temperature measures were made along nine axial positions and the composition of the products reaction were evaluated by gas chromatography. The experimental conditions were: temperatures furnace of 500ºC, 600ºC, and 700ºC, feed molar ratio [H2O/CH4] = 4, and mass flow rate of 0.2 and 0.5 kg/m2.s. The results show that the use of the nine points was enough to represent the thermal behavior of the reactor. Both the catalytic activity and the conversion depend of operational temperature. However, the fixed bedtemperature is independent of mass flow rate at the used experimental conditions.

  8. Electrochemical Characteristics of LaNi4.5Al0.5 Alloy Used as Anodic Catalyst in a Direct Borohydride Fuel Cell

    Institute of Scientific and Technical Information of China (English)

    Lianbang Wang; Guobin Wu; Zhenzhen Yang; Yunfang Gao; Xinbiao Mao; Chun'an Ma

    2011-01-01

    Fuel cells using borohydride as the fuel have received much attention because of high energy density and theoretical working potential. In this work, LaNi4.5Al0.5 hydrogen storage alloy used as the anodic material has been investigated. It was found that the increasing; operation temperature was helpful to the open-circuit potential, the discharge potential and the power density, but showed a negative effect on the utilization of the fuel due to the accelerated hydrogen evolution. The high KOH concentration was favorable for high-rate discharge capability. The adsorption and transformation of hydrogen on LaNi4.5Al0.5 alloy electrode has been observed, but its contribution to the discharge capability during a high-rate discharge was small.

  9. Homogeneous catalysts

    CERN Document Server

    Chadwick, John C; Freixa, Zoraida; van Leeuwen, Piet W N M

    2011-01-01

    This first book to illuminate this important aspect of chemical synthesis improves the lifetime of catalysts, thus reducing material and saving energy, costs and waste.The international panel of expert authors describes the studies that have been conducted concerning the way homogeneous catalysts decompose, and the differences between homogeneous and heterogeneous catalysts. The result is a ready reference for organic, catalytic, polymer and complex chemists, as well as those working in industry and with/on organometallics.

  10. Molybdenum carbide supported nickel-molybdenum alloys for synthesis gas production via partial oxidation of surrogate biodiesel

    Science.gov (United States)

    Shah, Shreya; Marin-Flores, Oscar G.; Norton, M. Grant; Ha, Su

    2015-10-01

    In this study, NiMo alloys supported on Mo2C are synthesized by wet impregnation for partial oxidation of methyl oleate, a surrogate biodiesel, to produce syngas. When compared to single phase Mo2C, the H2 yield increases from 70% up to >95% at the carbon conversion of ∼100% for NiMo alloy nanoparticles that are dispersed over the Mo2C surface. Supported NiMo alloy samples are prepared at two different calcination temperatures in order to determine its effect on particle dispersion, crystalline phase and catalytic properties. The reforming test data indicate that catalyst prepared at lower calcination temperature shows better nanoparticle dispersion over the Mo2C surface, which leads to higher initial performance when compared to catalysts synthesized at higher calcination temperature. Activity tests using the supported NiMo alloy on Mo2C that are calcined at the lower temperature of 400 °C shows 100% carbon conversion with 90% H2 yield without deactivation due to coking over 24 h time-on-stream.

  11. Combustion Synthesis during Flame Spraying (“CAFSY” for the Production of Catalysts on Substrates

    Directory of Open Access Journals (Sweden)

    Galina Xanthopoulou

    2017-01-01

    Full Text Available Combustion-assisted flame spraying (“CAFSY” has been used to produce catalytically active nickel aluminide coatings on ceramic substrates. Their catalytic activity was studied in CO2 (dry reforming of methane, which is particularly significant for environmental protection as well as production of synthesis gas (CO + H2. By varying the CAFSY processing parameters, it is possible to obtain a range of Ni–Al alloys with various ratios of catalytically active phases on the substrate. The influence of the number of coating layers and the type of substrate on the final catalyst composition and on the catalytic activity of the CAFSY coatings was studied and is presented here. The morphology and microstructure of the composite coatings were determined by scanning electron microscopy (SEM with energy-dispersive X-ray spectroscopy (EDX elemental analysis, X-ray diffraction (XRD, and Brunauer–Emmett–Teller (BET specific area analysis. Catalytic tests for dry reforming of methane were carried out using crushed pellets from the coatings at temperatures of 750–900 °C, and gas chromatography showed that methane conversion approached 88% whereas that of carbon dioxide reached 100%. The H2/CO ratio in the synthesis gas produced by the reaction varied from about 0.7 to over 1.2, depending on the catalyst and substrate type and testing temperature.

  12. Methanol steam reforming in a fuel cell drive system

    Science.gov (United States)

    Wiese, W.; Emonts, B.; Peters, R.

    Within the framework of the Joule III project a compact methanol reformer (CMR) with a specific weight of 2 kg/kW (lower heating value of H 2) was developed. This CMR contains a methanol and water vaporizer, a steam reformer, a heat carrier circuit and a catalytic burner unit. A laboratory fixed-bed reactor consisting of four tubes which could be filled with different amounts of catalyst was used to investigate the catalyst performance and the ageing behaviour. A hydrogen yield of 10 m N3/(h l Cat) can be achieved at 280°C. In this case, the methanol conversion rate is 95% and the dry product gas contains 0.9% CO. A linear decrease of the catalyst activity was observed which can be described by a loss of active catalyst mass of 5.5 mg/h. The catalyst was operated for more than 1000 h without having exhibited activity losses that made a catalyst change necessary. Besides, the stationary behaviour of the reforming reactor, the dynamic behaviour was studied. The time needed for start-up procedures has to be improved for reformers of a next generation. Moreover, the hydrogen production during reformer load changes will be discussed. Simulations of the power train in driving cycles show the different states of a reformer during dynamic operation.

  13. Methanol reformer with water vapor and oxygen in catalysts of Cu/CeO{sub 2}-ZrO{sub 2} to generate H{sub 2}; Reformado de metanol con vapor de agua y oxigeno en catalizadores de Cu/CeO{sub 2}-ZrO{sub 2} para generar H{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Aguila M, M.M. [ININ, 52750 La Marquesa, Estado de Mexico (Mexico)

    2007-07-01

    The environmental pollution is one of the problems more important to solve in the present time because its affect the quality of the alive beings' life. For such a reason alternatives have been looked for to diminish the percentage of air pollution (NO{sub x}, CO{sub x}, SO{sub x}, etc.), for they have been developed it the well-known catalytic converters. Another possibility is the energy use through fuel cells in vehicles using H{sub 2} as fuel free of CO (smaller concentration to 10 ppm). Processes exist for the production of H{sub 2} starting from the methanol and in this work the one was used reformed of methanol with water vapor and oxygen (OSRM) as the main reaction of this work. The primordial objective of this work consists on studying the catalytic properties of the copper (Cu) supported in mixed oxides (ZrO{sub 2}-CeO{sub 2}) in the reaction of having reformed of methanol with water vapor and oxygen for the production of H{sub 2}. Zirconia is synthesized (ZrO{sub 2}) and mixed oxides ZrO{sub 2}-CeO{sub 2} (with different relationship Zr/Ce) for the sol-gel method and the one cerium oxide (CeO{sub 2}) by direct combustion of the cerium nitrate. The oxides were stabilized thermally at 600 C by 5h. The catalysts were prepared by classic impregnation using copper acetate, the nominal concentration was of 3% in weight. The catalysts were roasted at 350 C and later on reduced in flow from H{sub 2} to 350 C for 1h. The characterization of the catalytic materials is carried out through different techniques as: adsorption-desorption of nitrogen to determine the surface area BET, scanning electron microscopy (SEM) to determine the final morphology of the catalysts, X-ray diffraction (XRD) to identify the crystalline phases of the catalytic materials and reduction to programmed temperature (TPR) to evidence the interaction metal-support. The catalytic properties of the catalysts were studied in the reaction CH{sub 3}OH + H{sub 2}O + O{sub 2}, to determine the

  14. Catalisadores sol-gel de Ni-SiO2 e Ni-Al2O3 aplicados na reforma de metano com CO2 = Ni-SiO2 and Ni-Al2O3 sol-gel catalysts applied to methane reforming with CO2

    Directory of Open Access Journals (Sweden)

    Giane Gonçalves

    2005-01-01

    Full Text Available A reação de reforma do metano com CO2 apresenta-se como um processopromissor de geração de gás de síntese e hidrogênio. Neste sentido, foram preparados catalisadores de níquel-sílica e níquel-alumina pelo método sol-gel, com carga metálica nominal de 8% em massa. Os catalisadores foram caracterizados por redução à temperatura programada, análise termogravimétrica e determinação da área superficial específica. A reação de reforma do metano com CO2 foi realizada em um micro-reator contendo 500 mg de catalisador, previamente ativado em uma mistura redutora contendo hidrogênio. Osensaios de reforma a seco do metano foram realizados a 800°C, na pressão atmosférica, por um período de 12 horas, com uma razão molar de alimentação de [CO2:CH4] = 6. Os produtos da reação foram analisados por cromatografia gasosa. Dentre os catalisadoresavaliados, nas condições de reação estudadas, o catalisador de níquel suportado em sílica foi o que apresentou o melhor desempenho.The dry reforming reaction of methane comes as a promising process of syngas and hydrogen. Nickel catalysts on Al2O3 and SiO2 were synthesized by sol-gel method, with metalic load of 8% weight. The catalysts were characterized by temperature programmed reduction (TPR, termogravimetry analysis (TGA and specific surface area measurements (BET. The dry reforming reaction was performed in a micro reactor packed with 500 mg of catalyst, previously activated in atmosphere of hydrogen. The dry reforming tests were done at 800oC and atmospheric pressure by a period of 12 hours, with a molar ratio in the feeding of [CO2:CH4] = 6. The products of the reaction were analyzed by gas chromatograph. The Ni-SiO2 catalysts showed better performance.

  15. Upgrading of reformate gas for different applications with focus on small-scale hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Jannasch, Anna-Karin; Silversand, Fredrik [CATATOR AB, Lund (Sweden)

    2004-12-01

    Hydrogen gas or hydrogen rich gas is today used in many different applications, i.e. as fuel in fuel cells or additive in vehicle fuel (i.e. hythane) and as reagent or reducing agent in different industrial product lines. The majority of the hydrogen is produced either via electrolysis or reformation, where this work has entirely been focused on the latter alternative. The overarching aims of this project have been to demonstrate the need for reformate purification for different applications, and then, to investigate different available methods that can be used in order to enable the requested gas clean-up. The different purification methods have been examined with respect to parameters such as operating conditions (temperature, pressure), impurity tolerance, size, weight and cost. Another goal of the project has been to investigate how the reformer fuel type used influences the reformate gas quality and hence, the need for gas purification before the reformate can be fed to e.g. a low temperature polymer membrane fuel cell (PEMFC). For this reason, some experimental work has been performed. First, analysis of the reformate gas composition when natural gas, LPG, gasoline, diesel, kerosene (low and high S-concentration (i.e. JP8)) and ethanol have been processed. The reformation tests were carried out in a small scale reformer unit ({approx} 1 kW H{sub 2}) including Catator's catalyst formulations developed for the steam reforming, the water gas shift and the preferential oxidation reaction, respectively. Verification tests, with synthetic gas blends, including different potential reformate impurities, and with real reformate gas were thereafter performed with a commercial 4-cell PEMFC stack (3-5 W). Finally, some examination and also to some extent further development of Catator's existing gas purification units were made, i.e. chemical (WGS, PROX) and physical (regenerative adsorption). The Pd-alloy membrane seems to be the obvious choice of purification

  16. Rhenium Nanochemistry for Catalyst Preparation

    Directory of Open Access Journals (Sweden)