Relationship between oxygen sorption properties and crystal structure of Fe-based oxides with double perovskite composition

Abstract

Efficient production of high purity oxygen by air separation is of great importance in both environmental and industrial processes. The Fe-based oxides with double perovskite composition were investigated as a new oxygen sorbent for the pressure swing adsorption (PSA) process, which is an efficient air separation method. The crystal structure and oxygen sorption properties of these perovskites prepared from the metal nitrates were examined by means of X-ray diffraction (XRD) analysis and the measurement of breakthrough curves, respectively. In addition, we examined the relationship between the amount of oxygen sorption and calculated the Goldschmidt's tolerance factor which is a key index to characterize the stability of perovskite structure.Among the prepared Fe-based perovskites, the Sr0.5Ba0.5FeO3−δ (SBFO) sample which has a cubic perovskite structure with a tolerance factor close to 1.0 showed the highest amount of sorbed oxygen at intermediate temperature of 450 °C. Moreover, the phase transition associated with the oxygen sorption/desorption in SBFO was observed at same temperature by means of the high-temperature XRD measurements.