First-principles Study of Direct Z-scheme In2SSe/Sb Heterostructure as Photocatalyst for Water Splitting

The photocatalytic properties of two-dimensional In2SSe/Sb van der Waals heterostructure were investigated via first-principles method. The results show that In2SSe/Sb heterostructure possesses the staggered band alignments with a direct band gap of 0.82 eV. As the built-in electric field is pointing from Sb to In2SSe at the interface, the In2SSe/Sb heterostructure exhibits type-Z mode, which is beneficial for effective electron-holes separations. Moreover, its band edges straddle water redox potentials and a strong optical absorption spectrum from visible light to ultraviolet light is obtained. Our study would offer theoretical understanding for designing In2SSe/Sb van der Waals heterostructure.