Electronic structure and photocatalytic performance of Janus MoSSe/Ga2SSe van der Waals heterostructures

Abstract

Recently, transition metal dichalcogenide photocatalysts have been substantially explored as efficient catalysts for water splitting. This paper systematically investigates the electronic structure and related properties of four, hitherto uninvestigated, Janus MoSSe/Ga2SSe vdW heterostructures using first-principles calculations. The results indicate that two out of the four heterostructures exhibit a type-II energy band arrangement, which facilitates the effective separation of electron-hole pairs in space. Additionally, the electrostatic potential, charge density difference and Bader charges analyses indicate that charge transfer in the interfacial region creates a built-in electric field that effectively inhibits electron and hole complexation, and that one out of the four heterostructures corresponds to a direct Z-scheme heterojunction. The optical absorption coefficients show that the MoSSe/Ga2SSe vdW heterostructures have a broad absorption range from visible to ultraviolet. These findings suggest that the Janus SMoSe/SGa2Se and SMoSe/SeGa2S vdW heterostructures could be suitable for photocatalytic water decomposition. The SMoSe/SGa2Se and SMoSe/SeGa2S vdW heterostructures have high corrected solar-to-hydrogen (STH) efficiency of 11.84% and 10.13%, respectively.