A CO2-tolerant dual phase membrane with composition of 60 wt% Ce0.9Gd0.1O2-delta-40 wt% Ba0.5Sr0.5Co0.8Fe0.2O3-delta (60CGO-40BSCF) was successfully developed. The 60CGO-40BSCF dual phase membrane showed good reversibility of the oxygen permeation fluxes and good stability in CO2 atmosphere. A stable oxygen permeation flux of 0.67 mL/min cm(2) was obtained with pure CO2 as the sweep gas during a 250 h oxygen permeation at 950 degrees C. The electronic conductivity results confirmed the concept that the electronic conductivity of the BSCF perovskite oxide could be partly reserved in CO2 atmosphere. Due to the high oxygen permeation fluxes and the good stability in CO2-containing atmosphere, the 60CGO-40BSCF dual phase membrane has great potential application in oxyfuel techniques for CO2 capture and storage. (C) 2013 Elsevier B.V. All rights reserved.