Ag-Regulated Interfacial Electron Transfer between TiO<sub>2</sub> and MoS<sub><i>x</i></sub> for Enhanced H<sub>2</sub>O<sub>2</sub> Production
Xidong Zhang, Jiachao Xu, Haoyu Long, Jiaguo Yu, Huogen Yu
Abstract
The electronic configuration mismatch between the TiO 2 support and the MoS x cocatalyst induces spontaneous free-electron transfer in an unfavorable direction, resulting in stronger O 2 adsorption on Mo active sites and causing limited H 2 O 2 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 TiO 2 /MoS x photocatalyst, which aims to weaken O 2 adsorption for improving H 2 O 2 production activity. To achieve this, a core–shell Ag@MoS x cocatalyst was ingeniously constructed on the TiO 2 surface to synthesize the TiO 2 /Ag@MoS x photocatalyst. The resultant TiO 2 /Ag@MoS x achieves a significantly enhanced H 2 O 2 production rate of 16.13 mmol g –1 h –1 with an AQY value of 8.79%, surpassing TiO 2 /Ag and TiO 2 /MoS x by 10.0 and 237.2 times, respectively. Theoretical calculations and experimental results reveal that the incorporation of the Ag mediator into the TiO 2 /Ag@MoS x system can facilitate directional free-electron transfer to the MoS x cocatalyst. This causes the creation of electron-enriched Mo (4 – δ)+ sites and an increase in the antibonding-orbital occupancy of Mo–O ads, ultimately weakening the Mo–O ads bond and enabling high activity in H 2 O 2 production. This study provides valuable insights into optimizing reactant adsorption for efficient artificial photosynthesis.