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

Abstract Designing highly efficient and stable electrode‐electrolyte interface for hydrogen peroxide (H 2 O 2 ) electrosynthesis remains challenging. Inhibiting the competitive side reaction, 4 e − oxygen reduction to H 2 O, is essential for highly selective H 2 O 2 electrosynthesis. Instead of hindering excessive hydrogenation of H 2 O 2 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 H 2 O 2 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 H 2 O 2 . 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.