Catalytic Properties of Perovskite-Type Mixed Oxides (ABO3) Consisting of Rare Earth and 3d Transition Metals. The Roles of the A- and B-Site Ions

Article abstract of DOI:10.1246/bcsj.61.621

The catalytic activities of perovskite-type mixed oxides (LnBO3 and Ln0.8Sr0.2CoO3, Ln=rare-earth (lanthanoid elements, B=3d transition metals) for the oxidation of propane and methanol have been studied comparatively.It has been found that the catalytic activities of LnBO3 were principally determined by the B-site elements and were similar to those of corresponding oxides of the B-site elements.The roles of the rare-earth ions of the A-site were secondary as long as they were trivalent.Upon the partial replacement of Ln³⁺ by Sr²⁺, the catalytic activities of LnCoO3 increased several times, the magnitude of the increase being similar among all the rare-earth ions.These results demonstrate that the kind and the valence of a B-site metal are of primary importance for the control of the catalytic activity for oxidation, almost regardless of the kind of trivalent rare-earth elements at the A-site.