Vacancy engineering of single-layer lateral heterojunction for efficient Z-scheme photocatalytic water reduction

Optimizing the Z-scheme charge transmission of lateral heterojunction constructed by single-layer (SL) nanosheets is an appealing yet challenging tactics to boost photocatalytic efficiency for solar fuel production and environmental remediation. Herein, we reported the edge/corner-specific growth of SL ZnIn 2 S 4 -MoSe 2 lateral heterojunction with intensified Z-scheme charge transmission through intimate Mo-S connection and S vacancies (V S ) engineering. The Mo-S chemical bonds inside ZnIn 2 S 4 -MoSe 2 heterojunction offer a speedy channel for Z-scheme charge transmission as confirmed via surface photovoltage spectroscopy, radical production, and in situ photo-irradiated X-ray photoelectron spectroscopy tests as well as density functional theory calculation, while V S engineering enlarges Fermi level difference between ZnIn 2 S 4 and MoSe 2 to strengthen internal electric field and driving force for photo-carriers transmission, resulting in an excellent photocatalytic H 2 evolution (PHE) capability. Isotopic labeling experiment verified the photocatalytic water reduction by ZnIn 2 S 4 -MoSe 2 heterojunction, which exhibited a visible-light-driven PHE rate up to 55.70 mmol g −1 h −1 (or 550.70 μmol/10 mg/h) with an apparent quantum yield reaching 38.9 % at 400 nm. Moreover, the ZnIn 2 S 4 -MoSe 2 heterojunction also possessed a robust stability during long-term photocatalytic reaction. The research findings could inspire new idea to enhance the photocatalytic capability of two-dimensional (2D) heterojunction by strengthening Z-scheme charge transmission at atomic level.