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.

Keywords: AC-electrocatalysis, 2e--ORR, three-phase interface, oxygen mass transfer, H2O2 production