Oxygen separation from air using Ba0.95La0.05FeO3−δ membranes fitted with porous La1−xSrxFeO3−δ layers

Selective oxygen separation from air was performed using perovskite-type oxide membranes made of Ba0.95La0.05FeO3−δ. We demonstrated that surface modification of Ba0.95La0.05FeO3−δ membranes with La1−xSrxFeO3−δ catalyst layers led to an increase in oxygen permeation fluxes at 700–930 °C. We studied the effects of oxygen vacancy amounts, surface area, particles size, surface treatment of La1−xSrxFeO3−δ on the oxygen permeability of the membranes fitted with La1−xSrxFeO3−δ catalyst layers. Among the catalyst layers tested, the membranes fitted with La0.9Sr0.1FeO3−δ (x=0.1) showed the highest oxygen permeation flux probably because of its higher porosity and uniform morphology without open voids, which would increase the number of surface reaction sites. The obtained results suggest the feasibility of further upgrading the membrane performance by using surface catalyst layers having a homogeneous morphology and a different composition from that of the mother membrane.