High flux and CO2-resistance of La0.6Ca0.4Co1-xFexO3-δ oxygen-transporting membranes

Most of the currently used perovskite-based oxygen-transporting membranes have insufficient resistance towards CO2 and high material costs that potentially limit their commercial applications. In the present work, a highly CO2-tolerant oxygen permeation membrane based on La0.6Ca0.4Co1-xFexO3-delta (x = 0, 0.3, 0.5, 0.7, 1) was designed and prepared by a scalable reverse co-precipitation method. The oxygen permeation flux through the dense membranes was evaluated and found to be highly dependent on the Co/Fe ratio. La0.6Ca0.4Co0.3Fe0.7O3-delta possessed the highest permeation flux among the investigated samples, achieving 0.76 ml min(-1)cm(-2) under an Air/He gradient and 0.5 ml min(-1)cm(-2) under an Air/CO2 gradient at 1173 K for a 1 mm thick membrane. A combination study of first principles calculations and experimental measurements was conducted to advance the understanding of Co/Fe ratio effects on the oxygen migration behavior in La0.6Ca0.4Co1-xFexO3-delta. The observed oxygen permeability is three times higher than that reported in literature under similar conditions. The presented results demonstrate that this highly CO2-tolerant membrane is a promising candidate for high temperature oxygen separation applications.