Lattice match-enabled Zn3In2S6@CdS S-scheme heterojunction with S covalent bond bridge for simultaneous H2O2 photosynthesis and H2 production

Abstract

The key to realizing artificial photosynthesis of hydrogen peroxide coupled with hydrogen generation lies in the construction of efficient bifunctional photocatalysts. Herein, we have successfully prepared core-shell Zn₃In₂S₆@CdS (ZIS@CdS) S-scheme heterojunction with matched interfacial lattices and S covalent bonding bridges by ion-exchange method. The combination of density functional theory calculations and experimental tests exhibit that the ZIS@CdS heterojunction interface with a lattice mismatch of ∼5% and the presence of two S covalent bonding forms, which provides stable and efficient channels for photogenerated charge transfer. Moreover, the photogenerated charges at the ZIS@CdS heterojunction interface follow the S-scheme transfer pathway, enabling spatial charge separation and high redox potentials. Under the synergistic effect of the matched interfacial lattice, covalent bond bridges, and built-in electric field, the ZIS@CdS heterojunction achieves an impressive H₂ evolution rate of 195.9 μmol g⁻¹ h⁻¹ and H₂O₂ production rate of 92.0 μmol g⁻¹ h⁻¹ without the need of sacrificial agent and oxygen bulging, respectively. This work verifies that coupling lattice matching and covalent bonding is an effective strategy for constructing efficient bifunctional photocatalysts.