Oxygen permeation through (Bi2O3)0.74(SrO)0.26–Ag (40% v/o) composite

The dense dual phase composite membrane made from strontium-stabilized bismuth oxide and silver, (Bi2O3)0.74(SrO)0.26–Ag (40% v/o), was investigated. The composite was found to exhibit very high electrical conductivity at the room temperature, revealing that the silver phase has formed electron-conducting networks in the oxide matrix. The composite shows much improved oxygen permeability compared with the bismuth oxide alone. An oxygen flux of 5×10−8 mol cm−2 s−1 was observed for a 1.00 mm thick composite at 700°C with oxygen partial pressures of the feed and permeate side at 0.209, 0.0024 atm, respectively. Combination of electrical conductivity and oxygen permeation measurements reveals that oxygen-ion conduction through the oxide phase of the composite is the rate-limiting step for oxygen permeation.