Influence of powder synthesis methods on microstructure and oxygen permeation performance of Ba_0.5Sr_0.5Co_0.8Fe_0.2O_{3- δ} perovskite-type membranes

Ba_0.5Sr_0.5Co_0.8Fe_0.2O_{3- δ} (designed as BSCF oxides) oxides prepared by different methods under the same sintering profile were examined in terms of microstructure and oxygen permeation performance. The oxide powders were synthesized by solid-state reaction, modified citrate and citrate-EDTA complexing method. Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) results revealed that the crystal structures of the powders synthesized by the three methods developed differently. Although the three kinds of powders have nearly the same particle size distributions, they showed different grain morphologies. Consequently, the membranes prepared from the three kinds of powders demonstrated different microstructures and different oxygen permeation fluxes. The membrane synthesized by the solid-state reaction method (designed as SS method) showed the highest oxygen permeability.