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

Abstract

Oxygenated groups functionalized carbon materials are promising catalysts for the electrochemical production of hydrogen peroxide (H2O2) via two-electron oxygen reduction reaction (ORR). Electrochemical activation of carbon materials to introduce oxygenated groups has exhibited attractive features compared with chemical oxidation method. 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. Composition analysis based on XPS and electrochemical FTIR indicates the successful modification of oxygenated groups. The production rate of H2O2 is significantly enhanced after potential cycling. The oxidized carbon electrode can catalyze 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 modification of oxygenated groups. These findings highlight the advantages of the electrochemical method on carbon surface functionalization and provide some guidelines for catalyst design.