A two-dimensional MoS2/SnS heterostructure for promising photocatalytic performance: First-principles investigations

MoS2-based two-dimensional (2D) heterostructure photocatalysts have attracted increasing attention due to their prominent photocatalytic performance, but still suffer from weak visible light absorption and low solar-to-hydrogen conversion efficiency. Herein, we comprehensively investigate the structural and electronic properties of 2D MoS2/SnS heterostructure using first-principles calculations. It is found that the MoS2/SnS heterostructure is a stable interface and forms a type-II heterojunction, which definitely facilitates the spatial separation and migration of photoexcited electron-hole pairs under light irradiation. More importantly, a relatively small band gap (roughly 0.29 eV) enables its light absorption spectrum to cover the entire visible light region. Interestingly, the Mo atoms in the MoS2/SnS heterostructure would turn into catalytic active sites. As a result, constructing heterostructure of MoS2 with SnS improves light absorption, accelerates the separation of electron-hole pairs, and activates the Mo atom at the basal plane, all of which could be beneficial to the photocatalytic activity. These results provide monolayer MoS2-based heterojunction photocatalysts and insightful understanding of their physical mechanism.