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

Designing highly efficient and stable electrode-electrolyte interface for hydrogen peroxide (H₂ O₂ ) electrosynthesis remains challenging. Inhibiting the competitive side reaction, 4 e^- oxygen reduction to H₂ O, is essential for highly selective H₂ O₂ electrosynthesis. Instead of hindering excessive hydrogenation of H₂ O₂ 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 H₂ O₂ 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 H₂ O₂ . 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.