Highly Efficient H₂O₂ Electrogeneration Enabled by Controlling the Wettability of Gas Diffusion Electrodes and the Reaction Pathway in Divided Cells

Efficient electrochemical synthesis of H₂O₂ via a two-electron oxygen reduction reaction (2e^--ORR) has been intensively pursued in the past few years, yet its potential application is still challenging due to the slow transportation of gaseous reactants and numerous competitive reactions in the electrolytic cell. Herein, we report that efficient electrochemical production of H₂O₂ can be achieved via tuning the wettability of the gas diffusion electrode (GDE) to the Wenzel-Cassie coexistence state (WCS) and controlling the electrochemical reaction pathway using a proton exchange membrane (PEM) divided cell. By tuning the wettability, the electrogeneration of H₂O₂ reached to 1326 mM with 59% current efficiency after 120 min. It is revealed that the reaction pathway for 2e^--ORR can be controlled by manipulating the crossover or diffusion of the ions or intermediate reactants via different membranes, and the electrogeneration of H₂O₂ is about 10 times higher in the PEM-divided cell compared to that in the undivided cell. These findings highlight the importance of GDE surface wettability and the reaction pathway for electrochemical synthesis of H₂O₂, paving an alternative way to develop efficient electrochemical synthesis systems.