Microstructural and Interfacial Designs of Oxygen-Permeable Membranes for Oxygen Separation and Reaction-Separation Coupling

Mixed ionic-electronic conducting oxygen-permeable membranes can rapidly separate oxygen from air with 100% selectivity and low energy consumption. Combining reaction and separation in an oxygen-permeable membrane reactor significantly simplifies the technological scheme and reduces the process energy consumption. Recently, materials design and mechanism investigations have provided insight into the microstructural and interfacial effects. The microstructures of the membrane surfaces and bulk are closely related to the interfacial oxygen exchange kinetics and bulk diffusion kinetics. Therefore, the permeability and stability of oxygen-permeable membranes with a single-phase structure and a dual-phase structure can be adjusted through their microstructural and interfacial designs. Here, recent advances in the development of oxygen permeation models that provide a deep understanding of the microstructural and interfacial effects, and strategies to simultaneously improve the permeability and stability through microstructural and interfacial design are discussed in detail. Then, based on the developed high-performance membranes, highly effective membrane reactors for process intensification and new technology developments are highlighted. The new membrane reactors will trigger innovations in natural gas conversion, ammonia synthesis, and hydrogen-related clean energy technologies. Future opportunities and challenges in the development of oxygen-permeable membranes for oxygen separation and reaction-separation coupling are also explored.