In situ evaluation of the electronic/local structure in B-site mixed perovskite-type oxide SrFe0.6Mn0.4O3−δ

Abstract Oxygen storage materials (OSMs) have potential as catalysts to purify automobile exhaust, electrode materials in solid oxide fuel cells and metal-air batteries, and electrolytes in solid oxide electrolysis cells. Perovskite-type oxides, ABO3, may enhance the OSM properties. Herein, the correlations between the oxygen desorption/absorption and the electronic and local structure in SrFe0.6Mn0.4O3-δ are evaluated by in situ X-ray absorption spectroscopy. Additionally, SrFeO3−δ and SrMnO3−δ are assessed to determine the difference in B-site mixed perovskite-type oxides. X-ray absorption near edge structure spectra showed the valence state of Fe ions in SrFe0.6Mn0.4O3−δ solely changes but the coordination symmetry of both Mn and Fe changes as the temperature rises. Hence, the oxygen release from the FeO6 octahedron accompanied variations of neighboring Mn–O polyhedrons. The oxygen desorption/absorption reaction depends on the interlocking changes in the local structure of the mixed B-site elements in the perovskite-type materials, suggesting that the B-site elements can be optimized for use as OSMs.