Effect of cation substitution in the A site on the oxygen semi-permeation flux in La0.5A0.5Fe0.7Ga0.3O3-δ and La0.5A0.5Fe0.7Co0.3O3-δ dense perovskite membranes with A = Ca, Sr and Ba (part I)

Numerous mixed ionic electronic conducting materials with a perovskite structure have been investigated in the literature as potential membrane materials for oxygen separation applications. However, the effect of cation substitution in the A site of a perovskite structure on the oxygen semi-permeation flux is not clearly understood. The goal of this paper is to provide insight into the effect of cation substitution in the A-site on oxygen semi-permeation flux in La(0.5)A(0.5)Fe(0.7)Ga(0.3)o(3-delta) and La(0.5)A(0.5)Fe(0.7)Co(0.3)O(3-delta) perovskite membranes with A = Ca, Sr, and Ba. In addition, the rate-determining step in the trans-membrane oxygen transport was clearly identified based on oxygen diffusion and oxygen surface exchange coefficients for these two perovskite membrane series. (C) 2014 Elsevier B.V. All rights reserved.