METHANE PARTIAL OXIDATION BY THE LATTICE OXYGEN OF THE LANIO3-D PEROVSKITE. A PULSE STUDY

LaNiO3 perovskite was prepared by the self-combustion method and tested as catalyst for CH4 activation using the oxygen lattice at 700°C and 800°C. Based on the non-stoichiometry experiments, the perovskite formula is written as La3+Ni3+0.37Ni2+0.63O2.68. When unreduced LaNiO3-d perovskite is used, only b-type oxygen species were responsible for the partial CH4 oxidation. Over non reduced perovskite high CH4 conversions to H2 and CO were obtained. CH4 conversion and H2, CO and CO2, selectivities under quasi-stationary conditions were 100%, 80%, 98% and 2 % respectively at 800°C. At the beginning of the reaction, a complete oxidation of methane to CO2 and H2O took place, whereas a partial oxidation to CO and H2 was observed after that period. In such conditions the H2/CO molar ratio obtained was 1.7, indicating a contribution of the parallel reverse water gas shift reaction