Catalytic Properties of Perovskite-type Mixed Oxides, La1−<i>x</i>Sr<i>x</i>CoO3

Abstract

Abstract The reactivity and related properties of oxygen both in the bulk and on the surface has been investigated for perovskite-type mixed oxides (La1−xSrxCoO3), in regard to the effects of Sr2+-substitution and calcination temperature. The reducibility and the readiness of oxygen desorption increased with the Sr2+ content, x, but the re-oxidation became slower with x. These results have been explained on the basis of the change in the chemical potential of lattice oxygen. The diffusivity of oxygen in the bulk and the ability to activate the oxygen molecule also increased with x. Oxygen vacancies in the bulk and on the surface, which tended to increase with x, are likely responsible for these reactions. The release of oxygen from the bulk became more difficult as the calcination temperature increased, in conformity with the trend of the catalytic activity.