Maximizing electrochemical hydrogen peroxide production from oxygen reduction with superaerophilic electrodes

Abstract This study investigated the effects of electrode wettability on hydrogen peroxide (H2O2) production from oxygen reduction reaction (ORR) during electrolysis with superaerophilic electrodes. When the electrode was in the underwater Wenzel-Cassie (UWC) state, it could quickly adsorb aerated oxygen microbubbles, which significantly enhanced oxygen transfer. Meanwhile, H2O2 reduction was effectively inhibited. Consequently, high ORR currents and current efficiencies (CEs) of H2O2 production could be obtained in the UWC state. However, oxygen can only be transferred to the electrode by dissolved oxygen (DO) diffusion when the electrode was in the underwater Wenzel (UW) state. Due to the slow DO diffusion and enhanced H2O2 reduction at the wetted electrode, the rate and CEs of H2O2 production decreased dramatically in the UW state. Maintaining a stable UWC state by controlling the rate of O2 bubbling and rate of O2 consumption in ORR is thus critical to maximizing H2O2 electrosynthesis with the superaerophilic electrodes.