Photocatalytic activity of co-doped Janus monolayer MoSSe for solar water splitting: A computational investigation

Janus transition-metal dichalcogenide is considered as a promising photocatalyst for solar water splitting because of its inherent internal electric field, tunable electronic and optical properties. However, the limited photocatalytic activity in the inert basal plane hinders its practical application. Here, we propose a heteroatom doping strategy to improve the catalytic activity of the monolayer MoSSe (ML-MoSSe) via charge compensated (N+F) and double-hole mediated (N+P) co-doping. We investigate the possibility of applying co-doped ML-MoSSe as the photocatalyst for water splitting by the first-principles calculations. The calculated results show that the N+F co-doped ML-MoSSe have the relatively higher thermodynamic stability and the reduced direct band gaps in the range of 1.28~1.57 eV with their band edge position satisfying the requirement of the redox potential of water at pH = 0 under the intrinsic polarized electric field. In particular, the doped N sites exhibit highly photocatalytic activity for hydrogen reduction reaction (HER). This work demonstrates that N+F co-doped ML-MoSSe might be a promising photocatalyst that possesses high catalytic activity for HER and simultaneously maintains the intrinsic polarized electric field to facilitate the separation of photogenerated carrier, which will shed light on screening the MoSSe-based photocatalyst. © 2020 Elsevier B.V.