Photocatalytic Reduction-Oxidation System for Synergistic Utilization of Photogenerated Electrons and Holes

The efficient and simultaneous utilization of photogenerated electrons and holes in photocatalytic reduction-oxidation (redox) reactions is currently an important trend in photocatalysis. This review systematically describes photocatalytic redox systems involving H₂ evolution, H₂O₂ evolution, CO₂ reduction, and NO₃^- reduction coupled with key oxidation reactions, respectively, to meet economic and sustainable goals. The general background and fundamental principles of photocatalytic coupled reactions are first introduced to provide a systematic understanding of the field. Thereafter, the research progress of H₂ evolution, H₂O₂ evolution, CO₂ reduction, and NO₃^- reduction coupled with various oxidation reactions, including H₂O oxidation, biomass and its derived platform molecules valorization, organics conversion, and pollutants treatment, respectively, is highlighted. Moreover, the commonalities and differences among photocatalytic coupled reactions are briefly summarized. Finally, the remaining challenges and future prospects of photocatalytic coupled reactions are critically discussed.