Electronic regulation of carbon sites by oxygenated groups for electrochemical oxygen reduction to H2O2

Abstract

The electrochemical two-electron oxygen reduction reaction (2eORR) for producing hydrogen peroxide (H₂O₂) has attracted significant attention as a potential alternative to the traditional anthraquinone process. In this study, we present a convenient method to regulate the electronic state of carbon sites using oxygenated groups, thereby achieving selective electrocatalytic O₂ reduction to H₂O₂. Oxidized Ketjen Black (KB-Ox) exhibits high oxygen content and good hydrophilicity, improving the accessible surface of the electrolyte. This results in excellent H₂O₂ selectivity (87.5% at an applied potential of 0.55 V vs. RHE) and stability (>80% over 8 h of long-term catalytic testing). Additionally, this convenient and mild method is used to enhance the 2eORR performance of graphene carbon (GC-Ox) and Super P (SP-Ox). Density functional theory (DFT) simulations further reveal that the aldehyde group (–CHO) effectively optimizes the electronic state and coordination environment of the carbon active site, leading to suitable bonding strength towards OOH*, ultimately achieving outstanding 2eORR performance. This work significantly guides the rational design and understanding of the catalytic mechanism of the carbon-based catalyst with high 2eORR activity.