Modulating Local Proton Coverage and *OOH Generation via Coupled Multiple Sites for Enhanced Photocatalytic H₂O₂ Production

Rationally modulating the adsorption of reaction intermediates on the surface sites of carbon nitride-based catalysts could facilitate the photocatalytic reduction of O2 to H2O2. Herein, theoretical calculations reveal that multiple sites of heteroatoms and defects can synergistically increase local proton coverage and lower the kinetic barrier for O2 protonation, thereby promoting the production of *OOH and the subsequent generation of H2O2. As a proof of concept, carbon nitride (BPMC-Vs) with multiheteroatoms (B and P) and multidefects (N defects, ─C≡N) was successfully synthesized, achieving optimized solar-to-chemical conversion efficiency and selectivity of 0.33% and 95.2%, respectively. In situ spectroscopic characterization combined with theoretical calculations confirms that P atoms and ─C≡N groups increase proton coverage, while B atoms and N defects effectively promote the protonation of O2 to *OOH, thereby significantly enhancing the generation of H2O2. This work provides insightful guidance for carbon nitride catalysis at the atomic scale for boosting photocatalytic H2O2 production.