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

Abstract

MoS 2 -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 MoS 2 /SnS heterostructure using first-principles calculations. It is found that the MoS 2 /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 MoS 2 /SnS heterostructure would turn into catalytic active sites. As a result, constructing heterostructure of MoS 2 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 MoS 2 -based heterojunction photocatalysts and insightful understanding of their physical mechanism. • The MoS 2 /SnS heterostructure is a stable interface and forms a type-II heterojunction. • The type-II heterojunction facilitates the spatial separation and migration of electron-hole pairs under light irradiation. • Small band gap enables its light absorption spectrum to cover the entire visible light region. • The Mo atoms in the MoS 2 /SnS heterostructure would turn into catalytic active sites.