Two-dimensional heterostructures for photocatalytic water splitting: a review of recent progress

Photocatalysts for water splitting are of particular importance to a renewable energy based energy and economic landscape. Two-dimensional (2D) semiconductors hold significant promise because of their large surface area compared to bulk photocatalysts. To overcome the crucial problem of the short lifetime of photogenerated charges, 2D van der Waals (vdW) heterostructures are being considered due to their awesome ability to separate photogenerated electrons and holes. This review summarizes the state-of-the-art studies on the topic of 2D photocatalysts, especially vdW heterostructure, for water splitting. After demonstrating the fundamental concepts of the light-driven redox reaction for water splitting, we discuss a number of promising 2D vdW heterostructures, highlighting the transition metal dichalcogenides and phosphorene based heterostructures, from both theoretical and experimental insights. Finally, we discuss the opportunities and challenges in this area of investigation. This article presents the advanced understanding of 2D vdW heterostructures in photocatalysis, which provides new opportunities for improving the efficiency of hydrogen generation from water splitting.