High-purity oxygen via dense ceramic membranes: A strategic review of materials, methods, and future horizons

High purity oxygen is crucial for both environmental sustainability and various industrial processes, particularly in clean energy technologies. To replace conventional, energy-intensive methods for oxygen separation in air, i.e., cryogenic distillation and pressure swing absorption, the application of dense ceramic membranes is emerging as a potential technology. These membranes offer simpler operation and significant energy conservation for oxygen separation. Herein, this review systematically examines the latest research progress of dense ceramic membranes for oxygen separation. Firstly, the introduction of the nine-step oxygen permeation process, summarized as oxygen surface exchange and bulk diffusion. Secondly, the four main phase structures of ceramic materials are introduced. Next, we present comprehensive methods for ceramic membrane preparation to provide practical synthesis insights for researchers. Whereafter, sealing and joining technologies, module design and scale-up of ceramic membranes are discussed in this review. Finally, we conclude with future development trends to help expand the potential of membrane applications, offering a crucial theoretical basis and guidance for the field.