Interfacial Charge Modulation of Covalent Metal-Organic Frameworks for Efficient H₂O₂ Electrosynthesis

Electrochemical H₂O₂ synthesis through the two-electron oxygen reduction reaction offers a sustainable alternative to the energy-intensive anthraquinone process. Crystalline porous frameworks are attractive for this route because of their structural precision, yet poor electrolyte wetting and limited electrochemical accessibility often restrict their practical performance. Here, we report an interfacial charge-modulation strategy that transforms covalent metal-organic frameworks into highly wetted and electrochemically accessible catalytic interfaces. By incorporating cationic ethidium bromide units into a trinuclear copper-pyrazolate framework, we construct EB-Cu₃-COF featuring enlarged interlayer spacing, enhanced interfacial charge transfer, and optimized *OOH intermediate adsorption. Consequently, EB-Cu₃-COF achieves up to 99% H₂O₂ selectivity and a flow-cell production rate of 39 420 mmol·g_cat ^-1·h^-1, ranking among the best-performing non-pyrolyzed porous organic electrocatalysts reported to date. This work establishes interfacial charge-modulation as a design principle for translating crystalline structural precision into electrochemically active interfaces.