  A series of composites based on
(100-x)wt.%Ce0.9Pr0.1O2-{\delta}-xwt.%Pr0.6Ca0.4FeO3-{\delta} (x = 25, 40 and
50) doped with the cheap and abundant alkaline earth metal Ca2+ at the A-site
has been successfully designed and fabricated. The crystal structure, oxygen
permeability, phase and CO2 stability were evaluated. The composition of
60wt.%Ce0.9Pr0.1O2-{\delta}-40wt.%Pr0.6Ca0.4FeO3-{\delta}(60CPO-40PCFO)
possesses the highest oxygen permeability among three studied composites. At
1000 oC, the oxygen permeation fluxes through the 0.3 mm-thickness 60CPO-40PCFO
membranes after porous La0.6Sr0.4CoO3-{\delta} each to 1.00 mL cm-2 min-1 and
0.62 mL cm-2 min-1 under air/He and air/CO2 gradients, respectively. In situ
XRD results demonstrated that the 60CPO-40PCFO sample displayed a perfect
structural stability in air as well as CO2-containing atmosphere. Thus,
low-cost, Co-free and Sr-free 60CPO-40PCFO has high CO2 stability and is
economical and environmental friendly since the expensive and volatile element
Co was replaced by Fe and Sr was waived since it easily forms carbonates.
