Solvent Engineering of Oxygen-Enriched Carbon Dots for Efficient Electrochemical Hydrogen Peroxide Production

The development of cost-effective and reliable metal-free carbon-based electrocatalysts has gained significant attention for electrochemical hydrogen peroxide (H2O2) generation through a two-electron oxygen reduction reaction. In this study, a scalable solvent engineering strategy is employed to fabricate oxygen-doped carbon dots (O-CDs) that exhibit excellent performance as electrocatalysts. By adjusting the ratio of ethanol and acetone solvents during the synthesis, the surface electronic structure of the resulting O-CDs can be systematically tuned. The amount of edge active C-O group was strongly correlated with the selectivity and activity of the O-CDs. The optimum O-CDs-3 exhibited extraordinary H2O2 selectivity of up to 96.55% (n = 2.06) at 0.65 V (vs RHE) and achieved a remarkably low Tafel plot of 64.8 mV dec(-1). Furthermore, the realistic H2O2 productivity yield of flow cell is measured to be as high as 111.18 mg h(-1) cm(-2) for a duration of 10 h. The findings highlight the potential of universal solvent engineering approach for enabling the development of carbon-based electrocatalytic materials with improved performance. Further studies will be undertaken to explore the practical implications of the findings for advancing the field of carbon-based electrocatalysis.