A review on dual-phase oxygen transport membranes: from fundamentals to commercial deployment

Oxygen transport membranes (OTMs) are a promising alternative to cryogenic air separation (ASU) or pressure swing adsorption (PSA) for oxygen production. Using these ceramic membranes allows producing high purity oxygen on various scales in a continuous single-step process, at lower costs and power consumption, making it an advantageous technique for oxy-combustion in connection with carbon capture and delocalized oxygen production on a small scale. Moreover, their use in membrane reactors, directly utilizing the permeating oxygen in chemical reactions towards green chemistry, is an emerging research field. Especially dual-phase OTMs, where the membrane consists of a composite of a stable ionic conductor and a stable electronic conductor, are of high interest, because they can overcome the disadvantages of single-phase membranes like low chemical and mechanical stability at elevated temperatures and under harsh operation conditions. However, despite the progress in the development of dual-phase OTMs over the last years, and their potential applications in classic and emerging fields, challenges preventing their large-scale employment remain. This review aims to guide new studies that will promote the development and upscaling of dual-phase OTMs. Recent developments, current opportunities and challenges, and future directions of research are thoroughly discussed. Through this review paper, information about the basic working principle, properties, performance and current application in industry of dual-phase OTM membranes can be comprehended. Next to material properties, preparative methods and manufacturing are in focus, intending to accelerate development and upscaling of new materials and components. Furthermore, existing challenges and research strategies to overcome these are discussed, and focus areas and prospects of future application areas are suggested.