Oxygen permeability and structural stability of Zr-doped oxygen-permeable Ba0.5Sr0.5Co0.8Fe0.2O3−δ membrane

Oxygen-permeable ceramic membrane materials of Ba0.5Sr0.5Co0.8Fe0.2O3−δ (BSCFO) and Fe-substituted partially Ba0.5Sr0.5Co0.8Fe0.1Zr0.1O3−δ (BSCFZO) were synthesized by solid state reaction method. The BSCFO material possess purely cubic perovskite structure, while minor impurity phase (Ba,Sr)ZrO3 exists in the perovskite-type BSCFZO material. Oxygen permeability of these dense membrane disks was measured at different temperatures (973–1123 K). The reduced oxygen permeability of BSCFZO was resulted from the decrease of the oxygen vacancy concentration and ionic conductivity due to the dissolution of Zr4+ in the B-sites of BSCFO. However, good stability of oxygen permeation of BSCFZO membrane was achieved at the temperature lower than 1123 K. Structural stability of the BSCFZO material was studied by the high temperature XRD technique, which demonstrated that its stability was significantly improved when the Fe ions in the B-sites of BSCFO were substituted partially by Zr4+ ions.