Oxygen permeability and stability in the entropy-stabilized Co-based Perovskite oxygen permeable membranes

Abstract

Oxygen transport membranes (OTMs), enabling catalytic reaction and gas separation, support crucial chemical engineering processes and decarbonization technologies, but their applications are hindered by limited oxygen permeation fluxes and inadequate long-term stability during operation. Here, a series of high-entropy perovskite OTMs based on La0.5Sr0.5CoO3 were designed and synthesized by the simple sol-gel method. The impact of varying doping ratios on the structure, surface morphology, oxygen permeability, and stability of these high-entropy OTMs was thoroughly examined. At 950 {\deg}C, the optimal composition, La0.25Sr0.25Gd0.2Nd0.2Pr0.1CoO3, achieved oxygen permeation fluxes of 1.62 mL min-1 cm-2 under air/He gradient and 1.46 mL min-1 cm-2 under air/CO2, respectively. Remarkably, all high-entropy OTMs demonstrated stable operation for over 100 h in a pure CO2 environment without a significant decline in performance. This finding paves a new way to enhance the structural and oxygen permeation stability of OTMs, and further promotes the application of OTMs in oxy-fuel combustion technologies aimed at improving CO2 capture and storage efficiency.