Promoting Dual‐Site Synergistic Hydrogen Bonding‐Mediated Proton‐Coupled Electron Transfer for Efficient One‐Step Photocatalytic H 2 O 2 Synthesis in Pure Water

ABSTRACT Photocatalytic oxygen reduction reaction (ORR) for H 2 O 2 synthesis represents a sustainable solar‐to‐chemical conversion route, yet its efficiency is severely limited by sluggish proton transfer and poor selectivity toward the direct one‐step two‐electron ORR pathway. Herein, two regioisomeric bipyridine‐based conjugated polymers with precisely tunable dual‐nitrogen (dual‐N) active site configurations are rationally constructed to address this challenge. The optimized BpyPh‐13 with a nearly coplanar and closely spaced dual‐N configuration enables strong intermolecular hydrogen bonding with water molecules, realizing direct and efficient proton conduction from water oxidation to dual‐N active sites via a dynamic Grotthuss‐type proton‐hopping mechanism. This efficient proton transfer process markedly accelerates proton‐coupled electron transfer kinetics and stabilizes the key *OOH intermediate against premature desorption into superoxide radical to avoid the inefficient stepwise ORR pathway. Consequently, BpyPh‐13 delivers a remarkable H 2 O 2 production rate of 4580 μmol g −1 h −1 under visible light irradiation in sacrificial agent‐free pure water, along with excellent cycling stability and near‐ideal 2e − ORR selectivity. This work establishes a clear structure–performance–selectivity relationship for dual‐N polymeric photocatalysts, providing a universal design principle for highly selective ORR photocatalysts toward efficient solar‐driven H 2 O 2 production.