Ag-Regulated Interfacial\nElectron Transfer between\nTiO₂ and MoS_<i>x</i> for Enhanced\nH₂O₂ Production

Abstract

The electronic configuration mismatch between the TiO₂ support and the MoS_<i>x</i> cocatalyst\ninduces\nspontaneous free-electron transfer in an unfavorable direction, resulting\nin stronger O₂ adsorption on Mo active sites and causing\nlimited H₂O₂ production. Herein, we propose\na strategy for directional free-electron transfer to produce electron-enriched\nMo^{(4 – δ)+} sites via introducing\nan Ag mediator into the TiO₂/MoS_<i>x</i> photocatalyst, which aims to weaken O₂ adsorption\nfor improving H₂O₂ production activity. To achieve\nthis, a core–shell Ag@MoS_<i>x</i> cocatalyst\nwas ingeniously constructed on the TiO₂ surface to synthesize\nthe TiO₂/Ag@MoS_<i>x</i> photocatalyst.\nThe resultant TiO₂/Ag@MoS_<i>x</i> achieves\na significantly enhanced H₂O₂ production rate\nof 16.13 mmol g^–1 h^–1 with an\nAQY value of 8.79%, surpassing TiO₂/Ag and TiO₂/MoS_<i>x</i> by 10.0 and 237.2 times, respectively.\nTheoretical calculations and experimental results reveal that the\nincorporation of the Ag mediator into the TiO₂/Ag@MoS_<i>x</i> system can facilitate directional free-electron\ntransfer to the MoS_<i>x</i> cocatalyst. This\ncauses 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\nand enabling high activity in H₂O₂ production.\nThis study provides valuable insights into optimizing reactant adsorption\nfor efficient artificial photosynthesis.