Theoretical study on the intrinsic properties of In2Se3/MoS2 as a photocatalyst driven by near-infrared, visible and ultraviolet light

Abstract

Two-dimensional photocatalysts with full optical absorption have attracted widespread attention for water splitting and pollutant degradation, but only few single materials can meet this criterion. In the present work, for the first time, we theoretically constructed an In₂Se₃/MoS₂ heterostructure composite and disclosed its outstanding oxidation ability for catalysis. The results revealed that the In₂Se₃/MoS₂ composite comprised van der Waals heterojunctions. With the binding energy of 0.315 J m⁻², the heterostructure was thermodynamically stable. An indirect band gap of 0.88 eV was obtained, which was smaller than that of the monolayer. Facilitated by the type-II heterostructure, there was migration of photoinduced electrons from MoS₂ to the In₂Se₃ monolayer, promoting the separation of charge carriers. Moreover, the mobility of the charge carriers in the composite was excellent because of their small effective mass and the outstanding optical absorption of infrared, visible and ultraviolet light. It was found that the electronic and optical properties were strain-tunable. Specifically, under a strain of 4%, the composite band changed from p-type to n-type, and the light absorption further broadened to the near-infrared region. Certain aspects of the theoretical findings were observed experimentally. It is envisioned that In₂Se₃/MoS₂ is a potential photoelectric material for experimental research in the area of photocatalysis.