Lanthanum Chromite Based Catalysts for Oxidation of Methane Directly on SOFC Anodes

Abstract

Catalytic properties of substituted lanthanum chromites were investigated for their use as anode materials for direct methane oxidation in solid oxide fuel cell (SOFC) anode materials. Different reaction mixtures were chosen to simulate the various SOFC operating conditions: partial oxidation, CO2 reforming by recycling, and H2O reforming. All experiments were performed in methane-rich atmospheres. Alkaline earth elements such as Ca, Sr, and Mg, and first series transition metals—Mn, Fe, Co, and Ni—were substituted into the LaCrO3 lattice. Three different catalytic behaviors were observed depending on the substituents. The Ni-substituted powders showed the highest activity toward CH4. Ni substitution showed also interesting H2O and CO2 reforming activities. For all catalysts, except in the case of Fe-substituted LaCrO3, only a small amount of carbon was detected on the surface (1∼3 monolayers). Among the investigated A-site and B-site substitutents, Sr and Ni were found to be the most active and the most suitable substitutents for the LaCrO3 SOFC anode purpose.