High-flux dual-phase percolation membrane for oxygen separation

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 degrees C, 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.