Efficient visible-light-driven photocatalytic hydrogen evolution in novel type-II SnS2/Al2S2 van der Waals heterostructures

Abstract

With the exacerbation of environmental pollution and the energy crisis, the development and design of environmentally friendly and efficient photocatalytic catalysts for water splitting with visible light have become particularly imperative. This study delves into the detailed investigation of the novel type-II van der Waals heterostructure of SnS2/Al2S2 utilizing first-principles calculation methods. By leveraging the advantages of indirect type-II band alignment and high carrier mobility, the efficient separation of electron-hole pairs is achieved, thereby facilitating enhanced participation of electrons and holes in photocatalytic reactions. Furthermore, the heterostructure manifests a peak optical absorption coefficient value of approximately 5.34×104 cm−1 in the visible light spectrum, accompanied by the occurrence of red-shifting, which fosters efficient absorption of visible light. It is noteworthy that under conditions of pH = 0–3.7, the heterojunction surpasses the redox potential of water splitting, concurrently displaying a substantial hydrogen evolution reaction (HER) and a high efficiency of converting sunlight to hydrogen (22.31 %). These results underscore the promising potential of the SnS2/Al2S2 heterostructure as a photocatalyst for water splitting, offering crucial theoretical support and practical guidance for the further advancement of hydrogen production via water splitting technology.