Mixed-conducting ceramic membrane reactors for hydrogen production

Hydrogen is widely used in industrial chemistry and acts as a promising clean energy carrier that can be produced from different hydrocarbons and water. Currently, the main sources of hydrogen are fossil fuels; however, they are associated with large CO₂ emissions. Alternatively, green hydrogen produced from water electrolysis using renewable energy is still far from large-scale industrial application owing to the poor reliability of renewable energy and water electrolysis. Therefore, the production of blue hydrogen, coupled with the CO₂ capture process, will play a dominant role in the near future in commercial hydrogen production. In this review, membrane reactor technologies based on ceramic-based dense membranes are comprehensively introduced. Membrane reactors are classified into three types according to the properties of the conductive carrier of membrane materials: (1) mixed protonic and electronic conductor (MPEC) membrane reactors, (2) mixed oxide-ionic and electronic conductor (MOEC) membrane reactors, and (3) mixed oxide-ionic and carbonate-ionic conductor (MOCC) membrane reactors. Their working principle, membrane materials, hydrogen sources, operating conditions, and performance are summarized. Finally, the challenges and prospectives of these membrane reactors are discussed for their future development.