Preparation of LaFe0.95Pd0.05O3 perovskites and their catalytic performances in methane combustion

The physic-chemical properties of LaFe0.95Pd0.05O3 perovskites were strongly dependent on the temperature of calcination.Most of the organic substances and inorganic impurities were readily removed at 723 K but single-phase and well crystallized perovskite structure was formed at 873 K.With further raising the calcination temperature,the crystallite size of LaFe0.95Pd0.05O3 increased considerably. The LaFe0.95Pd0.05O3 sample that calcined at 1073 K showed only comparable activity as the reference LaFeO3 catalyst,in particular below 923 K,but pre-treatment with the reaction gas at 1223 K resulted in significantly enhanced activity due to the generation of active PdO species on the surface.The hysteresis feature upon heating-cooling cycle further confirmed the strong interaction between Pd and LaFeO3 in the perovskite structure.