Catalytic activities and coking resistance of Ni/perovskites in steam reforming of methane

Steam reforming of methane for the purpose of hydrogen production was performed using nickel catalysts supported on a variety of perovskites, including LaAlO3, LaFeO3, SrTiO3, BaTiO3, La0.4Ba0.6Co0.2Fe0.8O3-delta, to compare the catalytic activity and resistance to coking of these catalysts to those of the conventional Ni/alpha-Al2O3 catalyst. Ni/LaAlO3 and Ni/SrTiO3 showed high catalytic activities among the Ni/perovskites and longer-term stabilities than the conventional catalyst. Temperature programmed oxidation of carbon deposited on used catalysts revealed that inactive carbon species detected on Ni/alpha-Al2O3 were not formed in the case of Ni/LaAlO3. The results of temperature programmed reduction confirmed that consumption and recovery of the lattice oxygen in perovskites occurred during the reaction, and that the reducibility of perovskites had a great impact on the steam reforming activity. The lattice oxygen in perovskites is considered to play important roles in promoting the oxidation of CH, fragments adsorbed on metallic nickel. (c) 2005 Published by Elsevier B.V.