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 H2O2 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 gcatalyst–1 h–1 and 523.5 mg cm–2 h–1, respectively. Finite-element simulations reveal periodic O2 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.
Tian et al. (Thu,) studied this question.