Efficient photoelectrodes based on two-dimensional transition metal dichalcogenides heterostructures: from design to construction

Hydrogen production by photoelectrochemical (PEC) water splitting converts the inexhaustible supply of solar radiation to storable H2 as clean energy and thus has received widespread attention. The efficiency of PEC water splitting is largely determined by the properties of the photoelectrodes. Two-dimensional (2D) layered transition metal dichalcogenides (TMDs) are promising candidates for photoelectrodes due to their atomic layer thickness, tunable bandgap, large specific surface area, and high carrier mobility. Moreover, the construction of 2D TMDs heterostructures provides freedom in material design, which facilitates the further improvement of PEC water splitting. This review begins by describing the mechanism of PEC water splitting and the advantages of 2D TMD-based heterostructures for photoelectrodes. Then, the design considerations of the heterostructures for enhanced PEC efficiency are comprehensively reviewed with a focus on material selection, band engineering, surface modification, and long-term durability. Finally, current challenges and future perspectives for the development of photoelectrodes based on 2D TMDs heterostructures are addressed.Graphical abstract