Electrosynthesis of Hydrogen Peroxide Synergistically Catalyzed by Atomic Co–N_x–C Sites and Oxygen Functional Groups in Noble-Metal-Free Electrocatalysts

Hydrogen peroxide (H₂O₂) is a green oxidizer widely involved in a vast number of chemical reactions. Electrochemical reduction of oxygen to H₂O₂ constitutes an environmentally friendly synthetic route. However, the oxygen reduction reaction (ORR) is kinetically sluggish and undesired water serves as the main product on most electrocatalysts. Therefore, electrocatalysts with high reactivity and selectivity are highly required for H₂O₂ electrosynthesis. In this work, a synergistic strategy is proposed for the preparation of H₂O₂ electrocatalysts with high ORR reactivity and high H₂O₂ selectivity. A Co−N_x−C site and oxygen functional group comodified carbon-based electrocatalyst (named as Co–POC–O) is synthesized. The Co–POC–O electrocatalyst exhibits excellent catalytic performance for H₂O₂ electrosynthesis in O₂-saturated 0.10 m KOH with a high selectivity over 80% as well as very high reactivity with an ORR potential at 1 mA cm⁻² of 0.79 V versus the reversible hydrogen electrode (RHE). Further mechanism study identifies that the Co−N_x−C sites and oxygen functional groups contribute to the reactivity and selectivity for H₂O₂ electrogeneration, respectively. This work affords not only an emerging strategy to design H₂O₂ electrosynthesis catalysts with remarkable performance, but also the principles of rational combination of multiple active sites for green and sustainable synthesis of chemicals through electrochemical processes.