METHANE COMBUSTION OVER B-SITE PARTIALLY SUBSTITUTED PEROVSKITE-TYPE LAFEO3 PREPARED BY SOL-GEL METHOD

Ultrafine perovskite-type complex oxides LaFe(1-y)A(y)O(3-lambda) (A-M n, Al, Co) were prepared by sol-gel method using citric acid as comple x agent, and characterized by XRD, TPR, TG and XPS techniques. The cat alytic activities for methane combustion were tested and compared with that of the large particle oxides having the same composition. It was shown that the catalytic activities of ultrafine LaFe(1-y)A(y)O(3-lam bda) complex oxides were much higher than that of LaFeO3 sample due to the increase of high valence B-site cations and lattice oxygen conten t by the substitution of B-site elements. Much higher catalytic activi ties were also observed for the ultrafine perovskite-type complex oxid es compared to their large particle counterparts.