A comprehensive comparative study of CO2-resistance and oxygen permeability of 60 wt % Ce0.8M0.2O2–δ (M = La, Pr, Nd, Sm, Gd) - 40 wt % La0.5Sr0.5Fe0.8Cu0.2O3–δ dual-phase membranes

In this study, dual-phase membranes 60 wt % Ce0.8M0.2O2–δ (M = La, Pr, Nd, Sm, Gd) - 40 wt % La0.5Sr0.5Fe0.8Cu0.2O3–δ (CMO-LSFCO) were prepared via a combination of EDTA-citric acid complexing sol-gel and mechanical mixture method. Their chemical compatibility, CO2 tolerance, oxygen permeability, conductivity, and long-term regenerative durability regarding the phase structure and composition were systematically studied. Among the studied CMO-LSCFO dual-phase membranes, CGO-LSFCO shows the highest oxygen permeability under air/He and air/CO2 gradients, which can be associated with the small particle size and high electronic conductivity of the CGO phase resulting in a good percolation with different transfer paths based on the correlations between membrane material characterization and oxygen permeability. The comprehensive comparative study presented in this work identifies the critical factors influencing the oxygen permeability, which may provide guidelines for designing further high performance dual-phase oxygen transport membranes.