AC-electrochemical synthesis of H2O2 by breathing O2 in three-phase interface

Abstract

Conventional electrosynthesis of H2O2 through a two-electron oxygen reduction reaction (2e− ORR) requires continuous O2 feeding as the reactant, which is produced by oxygen evolution reaction (OER) in water electrolysis. In principle, H2O2 can be directly synthesized from water once the 2e− ORR is coupled with OER in one electrode. Unfortunately, such effective coupling has not yet been established. Herein, we created a cyclic oxygen exhalation-inhalation for on-demand and on-site H2O2 production by coupling the OER and 2e− ORR with a facile alternating-current (AC) electrocatalytic process. By ingeniously manipulating the reaction interfaces and operating voltage, we achieved efficient and stable in-situ H2O2 production. The rapid oxygen transfer in the localized three-phase interface favors the sufficient electrochemical reactions. The AC-electrocatalytic system exhibits highest performance including H2O2 production rate of 90.16 mmol h−1 gcat−1. Moreover, such AC-electrocatalysis inspires a new strategy to combine multiple electrocatalytic reactions into one electrode for fundamental study and practical applications.