Simultaneous synthesis of oxygen doped carbon electrodes at the anode and cathode via potential cycling for promoted H2O2 electrosynthesis†

Abstract

Carbon materials functionalized with oxygenated groups are promising catalysts for the electrochemical production of hydrogen peroxide (H₂O₂) through the two-electron oxygen reduction reaction (ORR). Compared to chemical oxidation methods, the electrochemical activation of carbon materials to incorporate oxygenated groups offers several appealing advantages. However, the knowledge is limited as to how electrochemical treatment influences the resulting ORR performance. Herein, we describe the synthesis of carbon electrodes modified with oxygenated groups at both anodic and cathodic sides by using potential cycling in neutral Na₂SO₄ solution. XPS composition analysis and electrochemical FTIR confirm the successful introduction of oxygenated groups. The H₂O₂ production rate increases significantly after potential cycling. The oxidized carbon electrode can catalyze the ORR at an industrial current density to produce H₂O₂ with selectivity close to 100% in a flow cell. Density functional theory (DFT) calculations demonstrate that the binding energy of *OOH is promoted after the modification of oxygenated groups, such as quinone/carbonyl and hydroxyl groups. These findings highlight the advantages of the electrochemical method on carbon surface functionalization and provide some guidelines for catalyst design.