Ag-Regulated Interfacial Electron Transfer between TiO₂ and MoS_<i>x</i> for Enhanced H₂O₂ Production

The electronic configuration mismatch between the TiO2 support and the MoSx cocatalyst induces spontaneous free-electron transfer in an unfavorable direction, resulting in stronger O2 adsorption on Mo active sites and causing limited H2O2 production. Herein, we propose a strategy for directional free-electron transfer to produce electron-enriched Mo(4 – δ)+ sites via introducing an Ag mediator into the TiO2/MoSx photocatalyst, which aims to weaken O2 adsorption for improving H2O2 production activity. To achieve this, a core–shell Ag@MoSx cocatalyst was ingeniously constructed on the TiO2 surface to synthesize the TiO2/Ag@MoSx photocatalyst. The resultant TiO2/Ag@MoSx achieves a significantly enhanced H2O2 production rate of 16.13 mmol g–1 h–1 with an AQY value of 8.79%, surpassing TiO2/Ag and TiO2/MoSx by 10.0 and 237.2 times, respectively. Theoretical calculations and experimental results reveal that the incorporation of the Ag mediator into the TiO2/Ag@MoSx system can facilitate directional free-electron transfer to the MoSx cocatalyst. This causes the creation of electron-enriched Mo(4 – δ)+ sites and an increase in the antibonding-orbital occupancy of Mo–Oads, ultimately weakening the Mo–Oads bond and enabling high activity in H2O2 production. This study provides valuable insights into optimizing reactant adsorption for efficient artificial photosynthesis.