Effect of Fe Content on the Properties of Perovskite-Related Oxides

A series of SrFexCo0.5O3-delta(x = 0.5, 0.75, 1.0, 1.25) powders have been synthesized by the citrate method. The effect of Fe content on the properties of the SrFexCo0.5O3-delta was investigated by X-ray diffraction (XRD), thermo-gravimetric analysis and differential scanning calorimeters (TGA/DSC). XRD results reveal that the phases of the SrFexCo0.5O3-delta powders depend upon the content of Fe. Variations in Fe-content and temperature play important effects on the oxygen loss of the SrFexCo0.5O3-delta samples. The phase transition from brownmillerite to perovskite structure in helium is strongly dependent on the content of Fe by TGA/DSC analysis. The phase transition temperature is 795, 853, 828 and 874 degrees C for SrFe0.5Co0.5O3-delta, SrFe0.75Co0.5O3-delta, SrFeCo0.5O3-delta and SrFe1.25Co0.5O3-delta, respectively. The oxygen sorption capacity of the products is closely related to the Fe content and temperature. The oxygen sorption capacity of the SrFe1.25Co0.5O3-delta sample increases rapidly from 790 degrees C with the highest oxygen sorption capacity of 6.83 x 10(-3) mmol/g at 870 degrees C exhibiting the good oxygen sorption capacity from 860 to 880 degrees C.