Explore the photocatalytic and electronic properties of WSSe/g-GeC van der Waals heterostructures.

Utilizing solar energy to split water (photocatalytic water-splitting) is a good solution for global warming. However, it is difficult to find suitable materials for photocatalytic water-splitting. In this paper, through HSE06 and GW-BSE calculations, it is found that vdWHs with Se facing g-GeC (WSSe/g-GeC vdWHs) are an ideal photocatalytic material. The WSSe/g-GeC vdWHs can form a II-type band alignment, and the band gap exceeds the free energy of water splitting. The built-in electric field from Janus WSSe and vdWHs can effectively separate photo-generated electron–hole pairs and improve carrier lifetime. Compared with single-layer WSSe, WSSe/g-GeC vdWHs exhibit smaller exciton binding energy, especially for the WSSe/g-GeC vdWH I stacking (0.32 eV). Furthermore, WSSe/g-GeC vdWHs are of high absorption coefficient in the visible light regions, showing significant advantages of using solar energy. These findings imply that the WSSe/g-GeC vdWHs are promising as candidate material for photocatalytic water-splitting. [ABSTRACT FROM AUTHOR]