Homogeneous porous perovskite supports for thin dense oxygen separation membranes

Porous La1−xSrxCoO3−δ substrates (x=0.7, 0.5 and 0.2) were prepared as supports for thin mixed ionic-electronic conducting perovskite membranes. The preparation method is based on pyrolythic powder preparation, followed by high temperature calcination to reduce the sinter activity of the powder. Subsequently, the powder is homogenised by sieving and clarification through sedimentation. After isostatic pressing followed by sintering, the supports were 30% porous with a mean pore diameter of around 1 μm for the compositions with x=0.7 and 0.5. A coating of the same compositions as the support was applied to improve the surface morphology. At room temperature, the oxygen flux through the supports was 1.4×10−4 and 2.0×10−4 mole cm−2 s−1 for x=0.7 and x=0.5 respectively, at an absolute pressure difference of 1 bar. For the composition with x=0.2, the values of the pore diameter and oxygen flux were somewhat lower.