Heterostructured Photocatalysts for Water Splitting and the Interfacial Charge Transfer

Photocatalytic water splitting for hydrogen evolution has opened new possibilities for addressing energy and environmental issues. Type-II, direct Z-Scheme, and Schottky junction heterostructured photocatalysts have garnered attention due to their efficient light capture, reduced rate of carriers recombination, and spatially separated active sites. Understanding charge transfer mechanisms at the interface is critical for the development of high-performance photocatalysts. This review enumerates some of the latest research in various heterostructured photocatalysts for water-splitting hydrogen production. For Type-II and direct Z-Scheme heterostructure, we summarize a series of advanced characterization and computational methods for accurately probing interfacial charge transfer. For the composite system of metals and semiconductors, three main mechanisms and their applications are introduced: Schottky junctions, energy resonance transfer, and hot electron injection. It also discusses the contradiction between the Schottky barrier and hot electron injection as well as methods of regulating the barrier height.