First-Principles Investigation of MoS₂/MoSe₂-Janus XMoSiZ₂ (X = S, Se, Te; Z = N, P) Heterostructures as Photocatalysts for Water Splitting

Developing photocatalysts is one of the effective approaches to improve the production efficiency of renewable hydrogen energy. Based on density functional theory, the potential of MoS2/MoSe2-Janus XMoSiZ2 (X = S, Se, Te; Z = N, P) van der Waals (vdW) heterostructures as photocatalysts is predicted. The MoS2–TeMoSiN2 (S–Te), MoSe2–SMoSiP2 (Se–S), and MoSe2–SeMoSiP2 (Se–Se) heterostructures exhibit a Z-type charge transfer mechanism, with a broad light absorption range, high solar-to-hydrogen conversion efficiency, and carrier mobility. Meanwhile, the S–Te heterostructure can spontaneously and stably catalyze water splitting, demonstrating its potential as a high-performance photocatalyst. For the heterostructure composed of a Janus monolayer, the interface coupling characteristics can be effectively modulated by regulating the intrinsic and interfacial dipole, as well as the interfacial atomic electronegativity difference. The findings suggest that MoS2/MoSe2-Janus XMoSiZ2 vdW heterostructures are potential high-performance photocatalysts and provide critical theoretical support for the analysis of interfacial characteristics of heterostructures containing the Janus monolayer.