Oxygen permeation and stability of Mo-substituted BSCF membranes

Abstract

The oxygen permeation performance of Ba_0.5Sr_0.5Co_0.8−xFe_0.2−yMo_x+yO_3−δ (x + y = 0; 0.025; 0.05; 0.25; 0.375 for Co/Fe = 4 and x + y = 0.125 for Co/Fe = 2) ceramic perovskite materials was studied. The effects of the composition, structure, morphology and membrane thickness on permeation flux were investigated. We demonstrate how Mo substitution significantly improves the stability of BSCF membranes not only under static but also dynamic conditions by depressing the degradation rates at 750 °C. The highest permeation flux among the studied membranes was measured for a 1 mm thick Ba_0.5Sr_0.5Co_0.78Fe_0.195Mo_0.025O_3−δ as 1.55 ml min⁻¹ cm⁻² at 950 °C which is very close to the flux measured for BSCF (1.65 ml min⁻¹ cm⁻²) under the same conditions.