S-scheme heterojunction in photocatalytic hydrogen production.

• The S-scheme heterojunctions based on different typical photocatalysts are summarized. • Advanced characterization used to directly demonstrate the mechanism of S-scheme heterojunction is comprehensively summarized. • The future challenges and development trends of S-scheme heterojunction in the field of photocatalytic hydrogen evolution are pointed out. As an ideal secondary energy source, hydrogen has the title of clean energy and the product of its complete combustion is only water, which is not polluting to the environment. Photocatalytic hydrogen production technology is an environmentally friendly, safe, and low-cost strategy that requires only an inexhaustible amount of solar energy and water as feedstock. This paper provides a detailed and detailed review of S-scheme heterojunction photocatalysts for photocatalytic hydrogen production, mainly including TiO 2 -based, Perovskite-based, CdS-based, Graphitic phase carbon nitride-based, COF-based graphdiyne-based, ZnO-based, and ZnIn 2 S 4 -based S-scheme heterojunction photocatalysts. The classification of S-scheme heterojunctions is summarized. What's more, various characterizations for direct verification of the charge migration mechanism of S-scheme heterojunctions are outlined. Based on the present study, the future potential challenges and future research trends for S-scheme heterojunctions in photocatalytic hydrogen evolution technology are pointed out, which provides feasible strategies for the development and design of S-scheme heterojunction photocatalysts in the field of photocatalytic hydrogen evolution. [ABSTRACT FROM AUTHOR]