Bubble-assisted cleaning for primary amine oxidation towards ampere-level current densities

Abstract Organic molecular oxidation reactions are ideally regarded to be energy-saving alternative to replace oxygen evolution reaction (OER) for lowering the oxidation overpotential during green hydrogen production. However, the vast scale of hydrogen production is far beyond the fine chemical processes, inevitably resulting in substantial oxygen release. Here, we propose another type of coupled oxidation reactions to stably accommodate with high-current density hydrogen production, accompanied by easy separation. As taking benzylamine oxidation reaction (BOR) as a probe without other side reactions, we propose a bubble-assisted strategy by activating OER and utilizing the generated oxygen bubbles to timely take the insoluble product benzonitrile away from electrode surface, and effectively overcome the electrode poisoning issue. The assembled prototype water electrolyzer achieves a typical current density of 200 mA/cm 2 and faradaic efficiency of 55% at 1.65 V for over 40 hours, diversify high-value chemical outputs. Such hybrid electrolysis within bubble-assisted strategy endows system flexibility for next-generation integrated electrochemical energy platforms.