Partial Oxidation of CH4 over Ni/SrTiO3 Catalysts Prepared by a Solid-Phase Crystallization Method

Abstract Supported Ni catalysts on perovskite-type CaTiO 3 , SrTiO 3 , and BaTiO 3 oxides were prepared by the solid-phase crystallization ( spc ) method and tested for the partial oxidation of CH 4 to synthesis gas. The impregnation ( imp ) method was used for comparison. spc -Ni/SrTiO 3 showed the highest activity as well as the highest sustainability against both coke formation and reoxidation of Ni metal, followed by spc -Ni/BaTiO 3 , spc -Ni/CaTiO 3 , and then imp -Ni/SrTiO 3 . The order of the activity was clearly confirmed in the reaction at high space velocity. Both transmission electron microscopy and temperature-programmed reduction showed the presence of finely dispersed and stable Ni metal particles on the catalysts and their amount correlated well with the order of the catalytic activity. It is suggested that incorporation of Ni is enhanced in SrTiO 3 , followed by BaTiO 3 , and much less in CaTiO 3 , resulting in the higher dispersion of Ni metal particles on SrTiO 3 . Less heat was generated over spc -Ni/SrTiO 3 during CH 4 oxidation, suggesting that the heating of the catalyst bed by CH 4 combustion must be quickly compensated for by endothermic reforming reactions. Oxygen mobility was highest over spc -Ni/SrTiO 3 as judged from CO 2 pulse measurements. The high sustainability against coke formation may be due to the high activity of finely dispersed nickel metal particles for the reforming reactions partly assisted by the mobile oxygen on the catalyst.

[1]  Malcolm L. H. Green,et al.  Partial oxidation of methane to synthesis gas , 1990 .

[2]  H. Iwahara,et al.  Mixed conduction and oxygen permeation in the substituted oxides for CaTiO3 , 1988 .

[3]  T. Uchijima,et al.  Partial oxidation of CH4 to synthesis gas using an Rh |YSZ|Ag electrochemical membrane reactor , 1995 .

[4]  Luca Basini,et al.  Molecular and Temperature Aspects in Catalytic Partial Oxidation of Methane , 2000 .

[5]  J. Lunsford,et al.  Partial oxidation of methane to carbon monoxide and hydrogen over a Ni/Al2O3 catalyst , 1991 .

[6]  D. Kolar,et al.  The phase diagram of Catio3-SrTiO3 , 1987 .

[7]  Malcolm L. H. Green,et al.  A study of carbon deposition on catalysts during the partial oxidation of methane to synthesis gas , 1993 .

[8]  T. Tsunoda,et al.  Preparation and characterization of CaTiO3-based perovskitic oxides as catalysts for partial oxidation of light hydrocarbons , 1993 .

[9]  V. Choudhary,et al.  Nonequilibrium Oxidative Conversion of Methane to CO and H2 with High Selectivity and Productivity over Ni/Al2O3 at Low Temperatures , 1993 .

[10]  C. H. Bartholomew.  Carbon Deposition in Steam Reforming and Methanation , 1982 .

[11]  H. Kay,et al.  Structure and properties of CaTiO3 , 1957 .

[12]  F. Basile,et al.  Ni/Mg/Al anionic clay derived catalysts for the catalytic partial oxidation of methane : Residence time dependence of the reactivity features , 1998 .

[13]  Takashi Hayakawa,et al.  Partial oxidation of methane to synthesis gas over (Ca,Sr) (Ti,Ni) oxides , 1995 .

[14]  L. Schmidt,et al.  Production of Syngas by Direct Catalytic Oxidation of Methane , 1993, Science.

[15]  A. Cheetham,et al.  Catalytic conversion of methane to synthesis gas over europium iridate, Eu2Ir2O7: Anin situ study by x-ray diffraction and mass spectrometry , 1991 .

[16]  A. J. Murrell,et al.  Selective oxidation of methane to synthesis gas using transition metal catalysts , 1990, Nature.

[17]  J. Fierro,et al.  New catalytic routes for syngas and hydrogen production , 1996 .

[18]  F. Frusteri,et al.  Effect of calcination on the structure of Ni/MgO catalyst: an X-ray diffraction study , 1996 .

[19]  J. Lunsford,et al.  Are the equilibrium concentrations of carbon monoxide and hydrogen exceeded during the oxidation of methane over a nickel/ytterbium oxide catalyst? , 1993 .

[20]  A. York,et al.  A Sustainable Catalyst for the Partial Oxidation of Methane to Syngas: Ni/Ca1‐xSrxTiO3, Prepared In Situ from Perovskite Precursors , 1996 .

[21]  A. York,et al.  Sustainable Ni/Ca1−xSrxTiO3 catalyst prepared in situ for the partial oxidation of methane to synthesis gas , 1997 .

[22]  Kiyoharu Nakagawa,et al.  Transient Response of Catalyst Bed Temperature in the Pulsed Reaction of Partial Oxidation of Methane to Synthesis Gas over Supported Rhodium and Iridium Catalysts , 1999 .

[23]  Satoshi Hamakawa,et al.  CO2 reforming of CH4 over Ni/perovskite catalysts prepared by solid phase crystallization method , 1999 .

[24]  Raymond E. Kirk,et al.  Encyclopedia of chemical technology , 1998 .

[25]  J. Armor,et al.  The multiple roles for catalysis in the production of H2 , 1999 .

[26]  E. Tanabe,et al.  Study on the Anti-Coking Nature of Ni/SrTiO3 Catalysts by the CH4 Pyrolysis , 2001 .