Dual-vacancy-mediated polarization electric field in ZnIn2S4 for enhancing photocatalytic hydrogen evolution coupled with selective benzylamine oxidation

Nondirectional migration of photogenerated electron-hole pairs and the coordinated activation of multiple molecules are large barriers to simultaneous photocatalytic reactions. Here, ZnIn2S4 nanosheets with dual vacancies (DZIS) were synthesized using a facile hydrothermal and alkali-etching strategy. In the absence of cocatalysts, an outstanding photocatalytic hydrogen evolution rate (4650.1 µmol h−1) coupled with a selective benzylamine oxidation rate (7386.7 µmol h−1) was obtained over DZIS. Theoretical and experimental results uncovered that the dual vacancies induced a reorganization of electronic structure and enlarged the polarization electric field to promote the directional migration of charge carriers and exciton dissociation. Additionally, the Zn and S vacancies acted as active sites for the adsorption of H+ ions and benzylamine to reduce the surface reaction barrier. This work establishes a new method for the polarization electric field and provides a deep understanding of the hydrogen evolution mechanism.