Effect of B-site substitution on the stability of La0.2Sr0.8Fe0.8B0.2O3 − δ, B = Al, Ga, Cr, Ti, Ta, Nb

► B-site substituted La0.2Sr0.8FeO3-d as oxygen separation membranes ► We investigate the stability in reducing conditions ► Oxygen vacancy ordering suppressed by B-site substitution ► Kinetic stabilization of the perovskite lattice obtained with B-site substitution ► Highest stability for low ionic radius or high valence B-dopant