Oxygen semi-permeation performances of La1-xAxCo1-y-zFeyTazO3-δ perovskite (with A=Sr and Ba)

Cobalt-based perovskite oxides like La1-xSrxCo1-yFeyO3-delta or Ba1-xSrxCo1-yFeyO3-delta are considered as promising materials, because of very high oxygen semi-permeation. However, this perovskite material series presents a low chemical stability for industrial application due to the flexible redox behavior of cobalt. Then, recent studies show that the Ta co-doping on the B-site of perovskite structure improves the chemical stability under reducing conditions at high temperature. This paper is devoted to the study of La(1-x)A(x)Co(1-y-z)Fe(y)Ta(z)O(3-delta) perovskite systems (with A=Sr and Ba), and specifically the impact of Ta and Fe eloping on the chemical stability and oxygen semi-permeation performances. Besides, this work aims at better understanding of oxygen transport mechanism through the La(1-x)A(x)Co(1-y-z)Fe(y)Ta(z)O(3-delta) perovskite membranes (with A=Sr or Ba) that is not yet clearly identified. This better understanding involves dissociating the oxygen transport steps linked to oxygen diffusion in the membrane bulk and to the surface exchange on both membrane surfaces. (C) 2013 Elsevier Ltd. All rights reserved.