Effect of high surface area CeO2 and Ce-ZrO2 supports over Ni catalyst on CH4 reforming with H2O in the presence of O2, H2, and CO2

Abstract Methane steam reforming over Ni on high surface area (HSA) CeO 2 and Ce-ZrO 2 supports, synthesized by surfactant-assisted method, was studied and compared to conventional Ni/CeO 2 , Ni/Ce-ZrO 2 , and Ni/Al 2 O 3 . It was firstly observed that Ni/Ce-ZrO 2 (HSA) with the Ce/Zr ratio of 3/1 showed the best performance in terms of activity and stability. This catalyst presented considerably better resistance toward carbon formation than conventional Ni/CeO 2 , Ni/Ce-ZrO 2 , and Ni/Al 2 O 3 ; and the minimum inlet H 2 O/CH 4 ratio requirement to operate without the detectable of carbon are significantly lower. These benefits are related to the high oxygen storage capacity (OSC) of high surface area Ce-ZrO 2 support. During the reforming process, in addition to the reactions on Ni surface, the redox reactions between the absorbed CH 4 and the lattice oxygen (O x ) on CeO 2 and Ce-ZrO 2 surface also take place, which effectively prevent the formation of carbon on the surface of Ni. The effects of possible inlet co-reactant, i.e. H 2 O, H 2 , CO 2 , and O 2 on the conversion of CH 4 were also studied. It was found that H 2 presented positive effect on the CH 4 conversion when small amount of H 2 was introduced; nevertheless, this positive effect became less pronounced and eventually inhibited the conversion of CH 4 at high inlet H 2 concentration particularly for Ni/CeO 2 (HSA) and Ni/Ce-ZrO 2 (HSA). The dependence of H 2 O on the rate was non-monotonic due to the competition of the active sites, as have also been presented by Xu [1] , Xu and Froment [2,3] , Elnashaie et al. [4] and Elnashaie and Elshishini [5] . Addition of CO 2 inhibited the reforming rate, whereas addition of O 2 promoted the CH 4 conversion but reduced both CO and H 2 productions.

[1]  K. Otsuka,et al.  Partial Oxidation of Methane Using the Redox of Cerium Oxide , 1993 .

[2]  Said S.E.H. Elnashaie,et al.  Modelling, Simulation and Optimization of Industrial Fixed Bed Catalytic Reactors , 1994 .

[3]  G. Froment,et al.  Methane steam reforming, methanation and water‐gas shift: I. Intrinsic kinetics , 1989 .

[4]  K. Jun,et al.  Highly active and stable Ni/Ce-ZrO2 catalyst for H2 production from methane , 2002 .

[5]  A. Lemonidou,et al.  Carbon dioxide reforming of methane over 5 wt.% nickel calcium aluminate catalysts – effect of preparation method , 1998 .

[6]  Q. Huo,et al.  Organization of Organic Molecules with Inorganic Molecular Species into Nanocomposite Biphase Arrays , 1994 .

[7]  J. Kašpar,et al.  Surface and Reduction Energetics of the CeO2−ZrO2 Catalysts , 1998 .

[8]  D. Terribile.  The preparation of high surface area CeO2-ZrO2 mixed oxides by a surfactant-assisted approach , 1998 .

[9]  G. Ozin,et al.  Mesoporous Yttria–Zirconia and Metal–Yttria–Zirconia Solid Solutions for Fuel Cells , 2000 .

[10]  M. Mogensen,et al.  Preparation and Characterization of Copper/Yttria Titania Zirconia Cermets for Use as Possible Solid Oxide Fuel Cell Anodes , 2001 .

[11]  A. Isogai,et al.  The application of CeZr oxide solid solution to oxygen storage promoters in automotive catalysts , 1993 .

[12]  G. Stucky,et al.  Formation of a Porous Zirconium Oxo Phosphate with a High Surface Area by a Surfactant‐Assisted Synthesis , 1996 .

[13]  Pierre M. Petroff,et al.  Generalized synthesis of periodic surfactant/inorganic composite materials , 1994, Nature.

[14]  G. Froment,et al.  Methane steam reforming: II. Diffusional limitations and reactor simulation , 1989 .

[15]  N. Izu,et al.  Oxygen Evolution Properties of CeO 2 -ZrO 2 Powders as Automotive Exhaust Sub-Catalysts and the Phase Diagrams , 1995 .

[16]  P. Tanev,et al.  A Neutral Templating Route to Mesoporous Molecular Sieves , 1995, Science.

[17]  M. Hatano,et al.  Decomposition of water by cerium oxide of δ-phase , 1985 .

[18]  G. Ozin,et al.  Self-Assembling Solid Oxide Fuel Cell Materials: Mesoporous Yttria-Zirconia and Metal-Yttria-Zirconia Solid Solutions , 2000 .

[19]  Suttichai Assabumrungrat,et al.  Catalytic dry reforming of methane over high surface area ceria , 2005 .

[20]  F. Tietz,et al.  Structure – Property Relationships of Ni/YSZ and Ni/(YSZ+TiO2) Cermets , 2001 .

[21]  R. Gorte,et al.  A study of steam reforming of hydrocarbon fuels on Pd/ceria , 2002 .

[22]  J. S. Beck,et al.  Ordered mesoporous molecular sieves synthesized by a liquid-crystal template mechanism , 1992, Nature.

[23]  Mauro Graziani,et al.  Rh-Loaded CeO2-ZrO2 Solid-Solutions as Highly Efficient Oxygen Exchangers: Dependence of the Reduction Behavior and the Oxygen Storage Capacity on the Structural-Properties , 1995 .

[24]  R. Cataluña,et al.  Influence of Mutual Platinum-Dispersed Ceria Interactions on the Promoting Effect of Ceria for the CO Oxidation Reaction in a Pt/CeO2/Al2O3 Catalyst , 1998 .

[25]  M. S. Hegde,et al.  Promoting effect of CeO2 in a Cu/CeO2 catalyst: lowering of redox potentials of Cu species in the CeO2 matrix , 2001 .

[26]  S. Furukawa,et al.  Hydrogen spillover from NiO to the large surface area CeO2-ZrO2 solid solutions and activity of the NiO/CeO2-ZrO2 catalysts for partial oxidation of methane , 2001 .

[27]  N. Xanthopoulos,et al.  Lanthanum Chromite Based Catalysts for Oxidation of Methane Directly on SOFC Anodes , 2001 .

[28]  J. Kašpar,et al.  Relationship between the Zirconia-Promoted Reduction in the Rh-Loaded Ce0.5Zr0.5O2Mixed Oxide and the Zr–O Local Structure , 1997 .

[29]  J. Kašpar,et al.  NO decomposition over partially reduced metallized CeO2-ZrO2 solid solutions , 1994 .

[30]  L. Kershenbaum,et al.  84 Oxide catalysts in indirect internal steam reforming of methane in SOFC , 2003 .

[31]  Jackie Y. Ying,et al.  Synthesis of a Stable Hexagonally Packed Mesoporous Niobium Oxide Molecular Sieve Through a Novel Ligand‐Assisted Templating Mechanism , 1996 .

[32]  Young-Sam Oh,et al.  Methane reforming over Ni/Ce-ZrO2 catalysts: effect of nickel content , 2002 .

[33]  Moustafa A. Soliman,et al.  On the non-monotonic behaviour of methane—steam reforming kinetics , 1990 .

[34]  D. Chadwick,et al.  Reactivity of ceria, Gd- and Nb-doped ceria to methane , 2002 .

[35]  T. Hoost,et al.  An XRD and TEM Investigation of the Structure of Alumina-Supported Ceria–Zirconia , 1997 .

[36]  W. Cui,et al.  Partial oxidation of methane to syngas over nickel-based catalysts modified by alkali metal oxide and rare earth metal oxide , 1997 .

[37]  M. Hatano,et al.  Hydrogen from water by reduced cerium oxide , 1983 .

[38]  G. Ozin,et al.  Mesoporous Nickel−Yttria−Zirconia Fuel Cell Materials , 2001 .