A promising type-II ZnO/InS van der Waals heterostructure achieving high solar-to-hydrogen efficiency for photocatalytic water splitting

The development of highly efficient photocatalysts for solar water splitting represents a viable solution to address environmental pollution and the energy crisis. Herein, we constructed a novel two-dimensional (2D) type-II ZnO/InS van der Waals heterostructure and systematically investigated its electronic structure and photocatalytic properties based on first-principles calculations. Band structure calculations that explicitly consider spin–orbit coupling and interfacial dipole effects reveal that the ZnO/InS heterostructure exhibits a direct bandgap of 1.92 eV along with a type-II band alignment, which is highly favorable for the efficient spatial separation of photogenerated charge carriers. Furthermore, the band-edge positions of the heterostructure straddle the redox potentials of water, and it exhibits a high carrier mobility (2999.32 cm 2 ·V −1 ·s −1 ). Additionally, the application of biaxial strain effectively tunes the band edge positions and optical properties. A high solar-to-hydrogen conversion efficiency ( η STH ) of 25.28% was realized under a biaxial strain of ε = 6%. Overall, the ZnO/InS heterostructure demonstrates significant potential in its electronic and optical properties for photocatalytic water splitting. The construction and modulation strategy for this 2D heterostructure can provide theoretical insights for designing high-performance 2D photocatalysts.