Effect of cation substitution in the A site on the oxygen semi- permeation flux in La_(0.5)A_(0.5)Fe_(0.7)Ga_(0.3)O_(3-δ) and La_(0.5)A_(0.5)Fe_(0.7)Co_(0.3)O_(3-δ) dense perovskite membranes with A = Ca, Sr and Ba (part Ⅰ)

摘要

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-δ) and La_(0.5)A_(0.5)Fe_(0.7)Ga_(0.3)O_(3-δ) 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.