关键词: 二电子氧还原反应, 硒化镍, 氧掺杂碳量子点, 过氧化氢生产, 电子结构

Abstract: Modulating the electronic structure of electrocatalysts represents a widely employed strategy to enhance the oxygen reduction reaction (ORR) activity and H₂O₂ selectivity, yet achieving precise control over this process remains challenging. In this work, we introduce oxygen-doped carbon quantum dots (O-CQDs) into NiSe₂ nanoparticles/nanosheets to regulate the electronic structure of Ni active sites. This optimization promotes favorable O₂ adsorption and reduces the energy barrier for ^•OOH formation, thereby significantly boosting the electrocatalytic production of H₂O₂ via the two-electron (2e^-) ORR pathway. Combined spectroscopic analysis and density functional theory calculations reveal that the O-bridged interface facilitates electron transfer to surface Ni sites, strengthening O₂ adsorption in an "end-on" configuration and favoring the 2e^- ORR mechanism. The resulting O-bridged NiSe₂/CQDs catalyst exhibits outstanding 2e^- ORR performance under alkaline conditions, achieving a high H₂O₂ production rate of 7458.24 mmol g_cat^-1 h^-1 at 31.25 mA cm^-2 and a Faradaic efficiency of 92.88% at 0.5 V. The efficient degradation of the Rhodamine B and Methylene Blue is achieved by utilizing the electrolyte obtained after the H₂O₂ electrosynthesis process as a Fenton reagent. This study demonstrates that rational tailoring of interfacial charge distribution in hybrid catalysts provides an effective strategy for enhancing catalytic performance, offering a promising design principle for advanced electrocatalysts.

Key words: Two-electron oxygen reduction, reaction, Nickel selenides, Oxygen-doped carbon quantum dots, Hydrogen peroxide production, Electronic structure