Microstructure effect on the oxygen permeation through Ba _0.95La_0.05FeO_3-δ membranes fabricated by different methods

In order to investigate the effect of the microstructure on the oxygen permeation in Ba_0.95La_0.05FeO_3-δ membranes, three different methods such as solid-state reaction, nitrate and acetate decomposition (NAD), and amorphous malic acid precursor (AMP) methods were used to fabricate membranes with different grain sizes. The grain size of the membranes was successfully controlled from 35 to 829 μm² via sintering at 1175°-1275°C. The oxygen permeation fluxes through the Ba_0.95La_0.05FeO_3-δ membranes increased with a decrease in the grain size. The AMP method, using malic acid as a complexing agent, produced a membrane having the highest oxygen permeability (3.10 cm³·(min·cm²)^-1 at 930°C) and the smallest grain size. The results obtained again confirmed the significant importance of microstructure control in designing high-performance oxygen permeable membranes.