Dry reforming of methane over Ni perovskite type oxides

La1-xSrxNiO3 perovskite type oxides were synthesized by the auto combustion method and tested as catalysts precursors in the dry reforming of methane with CO2 to syngas at 700 degrees C and 1 atm. In order to understand the catalyst behavior, the reaction was studied by a pulse technique using a CH4/CO2 ratio close to one. The solids were characterized by X-ray diffraction (XRD), BET surface area, temperature-programmed reduction and oxidation (TPR-TPO) and scanning electronic microscopy (SEM). XRD analysis showed that reduction of the perovskites proceeds through formation of intermediate species to obtain Ni-0, La2O3 and SrO. LaNiO3 showed the higher activity among the studied perovskites while La2NiO4 was not active for the reaction. It was observed that catalytic activity was Sr content dependent, following the order: LaNiO3 > La0.6Sr0.4NiO3 > Ni (5%)/La2O3 > La0.9Sr0.1NiO3. During reaction, nickel remained as Ni-0 while SrCO3 and La2O2CO3 phases are formed which improved methane reforming and the regeneration of the La2O3 phase. The lack of carbon formation is attributed to the presence of these phases. (c) 2005 Elsevier B.V. All rights reserved.