Recent Progress and Perspectives of S-Scheme Heterojunction Photocatalysts for Photocatalytic CO2 Reduction

Photocatalytic CO2 reduction (PCO2RR) is regarded as a promising means to mitigate the effects of climate change and current energy shortage. However, photocatalysis is not very effective because of the rapid recombination of photogenerated electron–hole pairs. S-scheme heterojunctions can effectively separate photogenerated carriers and significantly improve the redox ability of photocatalysts. In recent years, S-scheme heterojunction photocatalysts have become a popular topic of research because of their superior photocatalytic performance. This review examines the recent research advancements in S-scheme heterojunction photocatalysts. First, the principle of PCO2RR is briefly introduced. Various types of heterojunctions are introduced, the charge transfer mechanisms and characterization methods of S-scheme heterojunctions are described, and the applications of metal oxides, metal sulfides, and other S-scheme photocatalysts in CO2 reduction are discussed and reviewed, respectively. In conclusion, the limitations and prospective directions of S-scheme heterojunction photocatalysts in CO2 photoreduction are discussed to provide direction for the design of high-performance S-scheme heterojunction photocatalysts.