Boosting Hydrogen Peroxide Electrosynthesis via Modulating the Interfacial Hydrogen‐Bond Environment

Designing highly efficient and stable electrode‐electrolyte interface for hydrogen peroxide (H2O2) electrosynthesis remains challenging. Inhibiting the competitive side reaction, 4 e− oxygen reduction to H2O, is essential for highly selective H2O2 electrosynthesis. Instead of hindering excessive hydrogenation of H2O2 via catalyst modification, we discover that adding a hydrogen‐bond acceptor, dimethyl sulfoxide (DMSO), to the KOH electrolyte enables simultaneous improvement of the selectivity and activity of H2O2 electrosynthesis. Spectral characterization and molecular simulation confirm that the formation of hydrogen bonds between DMSO and water molecules at the electrode‐electrolyte interface can reduce the activity of water dissociation into active H* species. The suitable H* supply environment hinders excessive hydrogenation of the oxygen reduction reaction (ORR), thus improving the selectivity of 2 e− ORR and achieving over 90 % selectivity of H2O2. This work highlights the importance of regulating the interfacial hydrogen‐bond environment by organic molecules as a means of boosting electrochemical performance in aqueous electrosynthesis and beyond. The addition of a hydrogen‐bond acceptor DMSO (dimethyl sulfoxide) into the KOH electrolyte improves the selectivity and activity of H2O2 electrosynthesis. The hydrogen bonds formed between DMSO and water molecules can reduce the activity of water dissociation to active H* species. The suitable H* supply environment improves the selectivity of H2O2 via suppressing 4 e− oxygen reduction.