A composite consisting of an O-ion conducting oxide, Ce0.8Sm0.2O2−δ (60vol%), and an electron-conducting oxide, La0.8Sr0.2CrO3−δ, was prepared by sintering a powder compact at 1550C. No significant reaction between the 2 oxides was observed under the preparation or O permeation conditions. Appreciable O permeation fluxes through the composite membrane were measured at high temperatures, with one side exposed to ambient air and the other to flowing He gas. The O flux initially increased with time, and required a long duration to reach a steady value. A steady O permeation flux as high as 1.4 x 10−7mol/cm2s was obtained for a 0.3mm-thick membrane at 950C under the relatively small O partial pressure difference of 0.21bar/0.0092bar. It was found that the overall O permeation process was limited mainly by transport in the bulk of the membrane at membrane thicknesses greater than about 1.0mm. Limitation by surface O exchange appeared at a reduced thickness of about 0.6mm.

Oxygen Permeation through a Ce0.8Sm0.2O2−δ–La0.8Sr0.2CrO3−δ Dual-Phase Composite Membrane. J.Yi, Y.Zuo, W.Liu, L.Winnubst, C.Chen: Journal of Membrane Science, 2006, 280[1-2], 849-55