Synthesis and characterization of gallium-based perovskite-type dense membrane with oxygen semipermeability

La0.15Sr0.85Ga0.3Fe0.7O3-delta (LSGFO) and La0.15Sr0.85Co0.3Fe0.7O3-delta ( LSCFO) mixed oxygen-ion and electron conducting oxides were synthesized by using a combined EDTA and citrate complexing method, and the corresponding dense membranes were fabricated. The properties of the oxide powders and me mbranes were characterized with combined SEM, XRD, H-2-TPR, O-2-TPD techniq ues, mechanical strength and oxygen permeation measurement. The results sho wed that LSGFO had much higher thermochemical stability than LSCFO due to t he higher valence stability of Ga3+. After the temperature-programmed reduc tion by 5% H-2 in Ar from 20 degreesC to 1020 degreesC, the basic perovskit e structure of LSGFO was successfully preserved. LSGFO also favors the oxyg en vacancy formation better than LSCFO. Oxygen permeation measurement demon strated that LSGFO had higher oxygen permeation flux than LSCFO, but they h ad similar activation energy for oxygen transportation, with a value of 110 and 117 kJ . mol(-1), respectively The difference in oxygen permeation flu xes was correlated with the difference in oxygen vacancy concentrations for the two materials.