The SWSe-BP vdW Heterostructure as a Promising Photocatalyst for Water Splitting with Power Conversion Efficiency of 19.4%

[Image: see text] Hydrogen generation by photocatalytic water splitting has drawn enormous research attention for converting sunlight and water into clean and green hydrogen fuel. However, the search for a high efficiency photocatalyst for water splitting is a key challenge. Two dimensional (2D) van der Waals (vdW) heterostructures as photocatalysts exhibit many advantages over the stacked original materials. In this article, we designed two novel 2D vdW heterostructures composed of WSSe and blue phosphorene (BP) monolayers, SWSe-BP and SeWS-BP, which are thermodynamically stable at room temperature. Using first-principles calculations, we found that the SWSe-BP vdW heterostructure can act as a potential photocatalyst for water splitting due to its robust stabilities, type-II band alignment, moderate bandgap, and suitable band edge positions for the redox reactions of water splitting, strong optical absorption, and excellent power conversion efficiency (PCE). Remarkably, the PCE of the SWSe-BP vdW heterostructure can achieve approximately 19.4% under a 3% biaxial tensile strain.