A novel heterogeneous La0.8Sr0.2CoO3-d/(La0.5Sr0.5)2CoO4+d dual-phase membrane for oxygen separation

Abstract

© 2018 Curtin University and John Wiley & Sons, Ltd. Dual-phase membrane is an attractive concept that combines the advantages of two different phases into single membrane matrix. The recently reported significant enhancement of oxygen surface kinetics on the La0.8Sr0.2CoO3-d (LSC)/(La0.5Sr0.5)2CoO4+d (LSC214) hetero-interface due to the formation of fast oxygen transport paths along hetero-interface is adopted into dual-phase membrane to achieve enhanced oxygen permeability. The 1300°C sintered LSC/LSC214 (4:1 weight ratio) hollow fiber displayed a maximum oxygen flux of 3.35 ml·min-1·cm-2 at 900°C and 200 ml min-1 helium sweep gas flow rate, which represents up to 80% enhancement relative to that of the 1300°C sintered LSC hollow fiber at the same experimental condition. Such enhancement is enabled by the enlargement of triple phase boundaries to larger areas across the membrane surface for dual-phase case as confirmed by the significantly lower area specific resistance for LSC/LSC214|Ce0.8Sm0.2O1.9 (SDC)|LSC/LSC214 relative to LSC|SDC|LSC symmetrical cell between 600°C and 800°C. This nominal dual-phase LSC/LSC214 hollow fiber also showed very stable fluxes of 3.3 and 2.3 ml·min-1·cm-2 during 300-hr permeation test at 900°C and 850°C, respectively.