Gaseous reactant feeding prolongs the durability of hydrophobic electrodes for H2O2 electrosynthesis

Engineering the hydrophobicity of electrode interfaces has been increasingly reported to enable favorable modulation of reactivity toward gas-consuming electroreduction reactions, yet effective strategies to maintain their durability under electrolysis and the fundamental mechanistic origins remain poorly understood. Herein, with the O 2 -to-H 2 O 2 conversion via two-electron oxygen reduction as a model, we demonstrate the critical role of O 2 feeding behavior in governing the stability of electrode hydrophobicity. In a typical submerged electrode system, several distinct O 2 feeding modes were created, including aeration-free, single-point aeration with low uniformity, and porous anode aeration with high uniformity. The unique coupling effect between O 2 feeding and feeding uniformity was then revealed experimentally and theoretically by combining long-term electrolysis, in situ monitoring, and COMSOL simulations. Specifically, the O 2 feeding operation allows for the stabilization of the global gas film of the hydrophobic electrode, while O 2 feeding in a uniform manner prevents the local gas film disappearance-induced chain loss of hydrophobicity. Based on this, the asymmetric structure (AS) cathode we designed achieved a long durability of 194 h in immersion operation, which is four orders of magnitude higher than the durability of the symmetric structure (SS) cathode. This study highlights the necessity of the interfacial consumption-replenishment equilibrium of gaseous reactants to stabilize electrode hydrophobicity, especially for the more promising gas diffusion electrodes.