Pulse study of CO2 reforming of methane over LaNiO3

The perovskite type oxide LaNiO3 was used as starting material for the CO2 reforming of methane. The reaction was studied by a pulse technique using a CH4/CO2 ratio close to one, in order to understand the catalyst behavior. LaNiO3 was reduced prior to the reaction by temperature programmed reduction (TPR) under hydrogen. The catalyst was thus composed of La2O3 and Ni-0. We have shown that good catalytic performances were obtained at 700 degreesC and 800 degreesC. At 800 degreesC all the CH4 was transformed whereas the CO2 conversion reached 92% with a H-2/CO ratio equal to 0.91. The crystallographic phases present after catalyst stabilization by the reaction depends on the reaction temperature. At 800 degreesC the only phases present are La, O-3 and metallic nickel whereas at 700 degreesC the spinel phase La2NiO4 was identified leading to the conclusion that the CO2 reforming of CH4 involve consecutive reactions occurring simultaneously in our experimental conditions: Ni-0 + La2O3 + CO2 <----> CO + La2NiO4 and CH4 + La2NiO4 --> CO + 2H(2) + La2O3 + Ni-0. (C) 2003 Elsevier B.V. All rights reserved.