High H2O2 production in membrane-free electrolyzer via anodic bubble shielding towards robust rural disinfection

Hydrogen peroxide (H 2 O 2 ) 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 2 O 2 . 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 2 O 2 degradation in the electrolyte. The H 2 O 2 production increases by ~600% compared to that using non-bubble shielded anode. A high H 2 O 2 concentration of 10.05 ± 0.05 g L −1 at 40 mA cm −2 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 2 O 2 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.