Dynamic Protonation on an Amino-Containing Quinone-Covalent Organic Framework Enables Efficient Neutral...

The electrosynthesis of hydrogen peroxide (H₂O₂) in neutral media is highly desirable for sustainable applications but is fundamentally limited by insufficient proton supply. Herein, we report a quinone-based covalent organic framework (Q-COFs) engineered with aromatic amino groups (TfpBQ) enables efficient neutral electrosynthesis of H₂O₂, achieved by the synergism between Q and amino groups. The amino groups serve as dynamic proton relays, boosting the interfacial proton-coupled electron transfer (I-PCET) kinetics of the Q redox couples, as evidenced by a high apparent rate constant (k_app) of 1.97×10⁴ s^-1, which is 43% and 92% higher than that of the imine- and amide-containing Q-COFs, respectively. Consequently, TfpBQ achieves a remarkable H₂O₂ yield of 19.3 mol g^-1 h^-1 with a Faradaic efficiency (FE) of 95.6% at 120 mA cm^-2 in a neutral electrolyte, while demonstrating exceptional stability during 60-h of continuous operation. Combined experimental and theoretical analyses demonstrate that the dynamic protonation of aromatic amino groups reconstructs the interfacial hydrogen-bond network, enabling a sustained proton supply to the adjacent Q/H₂Q redox cycle, which in turn optimizes the overall 2e^- ORR pathway. This work underscores the importance of managing dynamic protonation in electrocatalysts design for reactions occurring in proton-deficient microenvironment.