Lattice characteristics, structure stability and oxygen permeability of BaFe 1− xY xO 3− δ ceramic membranes

Abstract

BaFe 1− x Y x O 3− δ ( x = 0–0.2) materials were synthesized by conventional solid-state reaction process for oxygen separation application. The effects of Y-doping on the crystal structure development, electrical conductivity and oxygen permeability were evaluated. Yttrium introduction effectively stabilize the cubic structure of BaFe 1− x Y x O 3− δ . With Y-doping, the oxidation state of Fe ions reduces, resulting in the increase in oxygen vacancy concentration as charge compensation and the decreases in electrical conductivity. Y-doping enhances the structural stability of BaFe 1− x Y x O 3− δ in reducing atmosphere but decreases the oxygen permeability. Both of them are attributed to the strong binding energy of Y–O bond. The cobalt free membrane BaFe 0.95Y 0.05O 3− δ shows good structural stability under reducing atmosphere and acceptable oxygen permeation flux of 0.798 ml (STP) min −1 cm −2 at 900 °C for 1.1 mm thick membrane, making it a promising candidate for future practical applications.