Oxygen transport properties of nanostructured SrFe1 − xMoxO2.5 + 3/2x (0 < x < 0.1) perovskites

Doping of SrFeO2.5 with Мо6+ ions is accompanied by nanostructuring with the formation of 90° domains 10–20 nm in size with brownmillerite structure, as confirmed by X-ray diffraction, high-resolution electron microscopy, and Mossbauer spectroscopy. The evolution of the microstructure of SrFe1 − x Mo x O2.5 + 3/2x with temperature at low oxygen partial pressure was investigated by means of high-temperature X-ray diffraction; it was shown that nanodomain texture is stable to at least T ∼ 800 °C. Chronopotentiometry and permeability measurements demonstrate that the title compounds possess high oxygen mobility within a wide temperature range: oxygen diffusion coefficients at ambient temperatures are D = 10−13–10−12 cm2/s and oxygen fluxes at 960 °C for SrFeO3 − z (L = 1.42 mm) and SrFe0.95Mo0.05O3 − z (L = 1.5 mm) membranes in air/He gradient reach 0.25 and 0.19 μmol/(cm2 min), respectively.