Abstract: Photocatalytic H₂O₂ production from water and O₂ is a promising sustainable alternative to the traditional anthraquinone process, but its efficiency is often limited by sluggish O₂ activation and rapid charge recombination. Herein, an Au^δ+-Au/TpPa covalent organic framework photocatalyst was constructed via in situ photodeposition of Au species onto a β-ketoenamine-linked TpPa framework. Strong interfacial interactions between Au species and the TpPa framework trigger interfacial electron redistribution, resulting in the generation of electron-deficient Au^δ+ sites adjacent to metallic Au. The coexistence of electrondeficient Au^δ+ sites and metallic Au establishes an interfacial electron-transfer pathway, which not only accelerates charge separation and migration but also optimizes the local electronic environment for O₂ adsorption and activation. In addition, the localized surface plasmon resonance (LSPR) effect of Au nanoparticles enhances visible-light harvesting, while the ordered porous channels of TpPa provide a favorable microenvironment for proton transport. Consequently, the optimized Au^δ+-Au/TpPa photocatalyst achieves an H₂O₂ yield rate of 95.4 μmol g^-1 h^-1 under visible-light irradiation, which is more than twice that of pristine TpPa. This work provides new insights into interfacial electronic-structure engineering for developing efficient COF-based photocatalysts toward solar-driven H₂O₂ synthesis.

Key words: Photocatalytic H₂O₂ production, Au^δ+-Au dual sites, TpPa covalent organic frameworks, Interfacial electronic engineering, Two-electron oxygen reduction reaction