Oxygen Permeation Studies of Asymmetric Ba0.5Sr0.5Co0.8Fe0.2Ox Membranes

Asymmetric Ba0.5Sr0.5Co0.8Fe0.2Ox (BSCF) membranes, containing one thin film and one porous substrate with the same perovskite materials, were prepared by citrate-EDTA and isostatical pressing method. The asymmetric membranes were characterized by XRD, SEM and nitrogen permeation tests. All evidence shows that such membranes were crack-free and have the desired structures. The permeation fluxes under different situations (changing the thickness of the thin film and the porosity of the substrate) were examined. Compared with dense BSCF, the oxygen permeation performance of asymmetric BSCF membranes was enhanced dramatically (about 40-60% in the term of the permeation flux), which was attributed to a decrease in the limiting bulk diffusion. This paper presents the results of the effect of porosity and dense layer thickness on the oxygen permeation.