Lattice characteristics, structure stability and oxygen permeability of BaFe1-xYxO3-δ ceramic membranes

BaFe1-xYxO3-delta (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 BaFe1-xYxO3-delta. 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 BaFe1-xYxO3-delta 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 BaFe0.95Y0.05O3-delta shows good structural stability under reducing atmosphere and acceptable oxygen permeation flux of 0.798 ml (STP) min(-1) cm(-2) at 900 degrees C for 1.1 mm thick membrane, making it a promising candidate for future practical applications. (C) 2011 Elsevier B.V. All rights reserved.