Electron Transfer‐Proton Supply Decoupling at Functionalized Polymer Interfaces Enables Efficient Air‐Fed H ₂ O ₂ Electrosynthesis

Abstract

ABSTRACT Air‐fed electrochemical H 2 O 2 production via the two‐electron oxygen reduction reaction (2e − ORR) offers a sustainable alternative to conventional processes, yet its efficiency is fundamentally constrained by low O 2 availability and intrinsically coupled electron‐proton transfer. Here, we construct a bifunctional covalent organic polymer interface integrating carbonyl electron‐relay units and quaternary ammonium cationic motifs on commercial carbon black (QSPIP‐TMC@CB), enabling efficient H 2 O 2 electrosynthesis directly from air. The QSPIP‐TMC@CB delivers a H 2 O 2 production rate of 3410.1 mmol·h −1 ·g −1 with 91.4% H 2 O 2 Faradaic efficiency (FE H2O2 ) under air, and sustains stable operation at 100.0 mA·cm −2 for 35.0  h. Mechanistically, carbonyl motifs function as reversible redox mediators that facilitate electron injection into O 2 , while quaternary ammonium cations enrich interfacial O 2 and regulate proton accessibility via Donnan repulsion, suppressing excessive protonation of the *OOH intermediate and preventing O─O bond cleavage. This cooperative regulation decouples electron transfer from proton supply, thereby stabilizing the 2e − pathway under O 2 ‐lean conditions. The strategy is readily extendable to representative ORR catalysts (Co─N─C and ZnO) and enables gram‐scale H 2 O 2 production (4.8 g h −1 at 5.0 A, 1.0 wt% within 5 min), establishing functionalized‐interface electron‐proton decoupling as a general and scalable design paradigm for air‐fed H 2 O 2 electrosynthesis.