Synergy of Ag and\nInterfacial Oxygen Vacancies on\nTiO<sub>2</sub> for Highly Efficient Photocatalytic Production of\nH<sub>2</sub>O<sub>2</sub>

Photocatalytic H<sub>2</sub>O<sub>2</sub> production\nstands as\na promising sustainable technology for chemical synthesis. However,\nrapid charge recombination and limited oxygen adsorption by photocatalysts\noften limit its efficiency. Herein, we demonstrate that the synergy\nof Ag and interfacial oxygen vacancies on TiO<sub>2</sub> could overcome\nthese challenges. The optimized Ag/TiO<sub>2</sub>-50 photocatalyst\nachieved an impressive H<sub>2</sub>O<sub>2</sub> production rate\nof 12.9 mmol h<sup>–1</sup> g<sup>–1</sup> and maintained\na steady-state concentration of 12.8 mM, significantly outperforming\nmost TiO<sub>2</sub>-based photocatalysts documented in the literature.\nDetailed mechanistic studies, aided by TAS, <i>in situ</i> X-ray photoelectron spectroscopy (XPS), and <i>in situ</i> electron paramagnetic resonance (EPR) techniques, indicate that\nthe oxygen vacancies at the Ag–TiO<sub>2</sub> interface act\nas an interfacial hole trap, inducing a directional hole transfer.\nThis, coupled with Ag acting as an electron acceptor, synergistically\nboosts the electron–hole separation. Additionally, the increased\namount of oxygen vacancies at the Ag–TiO<sub>2</sub> interface\nof Ag/TiO<sub>2</sub>-50 leads to enhanced O<sub>2</sub> adsorption,\nthus contributing to its superior catalytic performance. This study\nprovides valuable insights into interfacial traps in the charge transfer\nprocess and highlights the potential of interface regulation for achieving\nefficient photocatalytic conversion.