High H<sub>2</sub>O<sub>2</sub> production in membrane-free electrolyzer via anodic bubble shielding towards robust rural disinfection.

Yi, Kexin; Li, Chao; Hu, Shaogang; Yuan, Xiayu; Logan, Bruce E; Yang, Wulin · Nat Commun · 2025

basic_science · Level V

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Abstract

Hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) can be sustainably synthesized through the electrochemical oxygen reduction reaction in a dual-chamber water electrolyzer separated by expensive ion exchange (IX) membranes. The development of an IX membrane-free electrolyzer has been limited by direct anodic degradation of the produced H<sub>2</sub>O<sub>2</sub>. Here, we devise a bubble shielding strategy by using a low-cost polytetrafluoroethylene hydrophobic porous layer (HPL) on the anode that enables numerous sites for anodically generated oxygen bubbles and significantly suppresses H<sub>2</sub>O<sub>2</sub> degradation in the electrolyte. The H<sub>2</sub>O<sub>2</sub> production increases by ~600% compared to that using non-bubble shielded anode. A high H<sub>2</sub>O<sub>2</sub> concentration of 10.05 ± 0.05 g L<sup>-1</sup> at 40 mA cm<sup>-2</sup> can be obtained with both HPL-coated anode and cathode. A solar-driven disinfection device equipped with HPL-coated electrodes achieves >99.9% E. coli inactivation within 60 min. This innovative approach for achieving high electrochemical H<sub>2</sub>O<sub>2</sub> concentrations in IX membrane-free electrolyzers more generally provides insights for fine tuning three-phase interfaces and could be applicable to other reactions pathways in electrochemical applications.