Surface heterojunction of photocatalysts

The efficiency of charge separation at the interface of heterojunction is a key factor that influences the photocatalytic performance of semiconductor photocatalysts. Surface heterojunction, which forms between different facets of a single semiconductor owing to the different atomic arrangements and electronic structures of the facets, is a promising strategy to spatially separate photogenerated charge carriers and promote the photocatalytic activity. In this chapter, progress on the exploration of surface heterojunction photocatalysts is summarized. The discussions mainly focus on the fundamentals of surface heterojunction, including the roles and evidences of surface heterojunction and the synthesis methods of surface heterojunction materials. Additionally, typical examples of surface heterojunction photocatalysts are discussed for a variety of semiconductors, including titanium dioxide, bismuth vanadate, copper(I) oxide, cerium(IV) oxide, bismuth oxychloride, copper tungsten sulfide, and silver-based semiconductors. These discussions are expected to bring deep understanding about the surface heterojunction photocatalysts and provide reference for future research on facet-dependent photocatalysis.