In-plane carrier regulation and hydrogen adsorption/desorption optimization of P4 molecule anchored Vs-ZnIn2S4−x for improve photocatalytic activity

Abstract

Molecular-type cocatalysts can achieve the maximum electron transfer and minimum light absorption loss by virtue of their size advantage. Herein, a novel hydrophilic molecule-semiconductor hybrid P4@Vs-ZnIn2S4−x photocatalyst was successfully developed by in-situ P4 molecular anchoring on S defect ZnIn2S4−x (VS-ZnIn2S4−x). The electron-rich P4 molecules are anchored on the Zn-S4 surface through S vacancies, forming Zn-P and S-P bonds that can promote electron injection from the electron-rich P4 molecular to Vs-ZnIn2S4−x substrate and reduce the adsorption/desorption barrier of H intermediate on S atom of Zn-S4 plane. Meanwhile, the electrostatic potential depression around P4 promoted the directional migration of in-plane photogenerated electrons, and pooled electrons to the highly active P sites and S sites, thereby accelerating the kinetics of hydrogen evolution. As a result, P4@Vs-ZnIn2S4−x achieves an optimal photocatalytic hydrogen evolution activity of 26.1 mmol g−1 h−1 under visible light, which is 6.2 times higher than 4.2 mmol g−1 h−1 for Vs-ZnIn2S4−x.