Maximizing electrochemical hydrogen peroxide production from oxygen reduction with superaerophilic electrodes

• Published in: Applied catalysis. B, Environmental Environmental, 2021-12, Vol.299, p.120655, Article 120655
• Main Authors: Xia, Guangsen, Tian, Yadong, Yin, Xiaomeng, Yuan, Wenhan, Wu, Xiaocui, Yang, Zhongxue, Yu, Gang, Wang, Yujue, Wu, Mingbo
• Format: Article
• Language: English
• Subjects: Aeration; Chemical reduction; Diffusion rate; Dissolved oxygen; Electrochemistry; Electrodes; Electrolysis; Hydrogen peroxide; Maximization; Optimization; Oxygen; Oxygen consumption; Oxygen reduction reaction; Oxygen reduction reactions; Oxygen transfer; Reduction (electrolytic); Superaerophilic electrode; Underwater; Underwater wetting state; Water treatment; Wettability; Wetted electrodes
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2021.120655

[Display omitted] •Superaerophilic electrodes can greatly enhance O2 transfer by adsorbing O2 bubbles.•The wetting state of superaerophilic electrode changes dynamically during ORR to H2O2.•The wetting state of superaerophilic electrode has significant effects on ORR to H2O2.•The best performance of ORR to H2O2 is obtained in the underwater Wenzel-Cassie State.•Proper gas management is needed to maintain a stable underwater Wenzel-Cassie state. 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.