Sr3Fe2O7-δ with layered perovskite structure shows an excellent oxygen storage performance and has significant potential in the fields of oxygen separators/sensors and the purification of polluted materials such as automobile exhaust gas. This review introduces effects of Pd loading on Sr3Fe2O7-δ and of doping with other transition metals (Mn, Co, Ni) into the Fe sites of Sr3Fe2O7-δ. Pd loading dramatically improves oxygen release rate under H2 atmosphere, because Pd species enhances the adsorption and dissociation of H2. Mn doping of Sr3Fe2O7-δ also increases the oxygen release rate of Sr3Fe2O7-δ. Although the local structures around the transition-metal species in Sr3(Fe0.8Co0.2)2O7-δ and Sr3(Fe0.8Ni0.2)2O7-δ are largely disordered by the release of lattice oxygen, the cation ordering of the as-synthesized Sr3(Fe0.8Mn0.2)2O7-δ was maintained by doping with Mn, even in the reduced state. These results indicate that the oxygen release rate under H2 atmosphere largely contributes to the surface reaction and structural changes in the perovskite structures upon release of lattice oxygen.
Keywords:Oxygen storage material, Perovskite structure, Sr-Fe mixed oxide, Automotive catalysts
Publication Date: 2019-07-25