Dual Regulation of Oxygen Transport and Interfacial Water Structure Enables High-Rate Acidic H 2 O 2 Electrosynthesis via Pulsed Potential Strategy

Modulation of the electrode–electrolyte interface via pulsed potential electrolysis (PPE) is underexplored for optimizing selectivity in competing reactions. Herein, PPE regulates interfacial mass transport and water structure, breaking the trade-off between current density and Faradaic efficiency (FE) in acidic H 2 O 2 electrosynthesis. Using oxidized acetylene black as a catalyst, PPE achieves 85.5% FE at −1.6 V vs RHE in an H-type cell, a 9.1-fold improvement over traditional constant potential electrolysis (CPE, 9.4%). Scaling up to a flow system, PPE maintains 92.2% FE at −0.5 A cm –2 and 80.9% at −1.0 A cm –2, with robust stability over 160 h. Notably, PPE delivers remarkable mass and areal activities of 102.6 mol g catalyst –1 h –1 and 523.5 mg cm –2 h –1, respectively. Finite-element simulations reveal periodic O 2 concentration refreshment at the interface, while in situ Raman spectroscopy shows dynamic modulation of the hydrogen-bonded water network during PPE. The enriched 4-coordinated hydrogen-bonded water species at the interface increase proton transfer resistance, effectively suppressing the competing hydrogen evolution reaction. This work establishes PPE as a versatile interfacial engineering strategy for enhancing electrocatalytic selectivity.