【摘要】 为了研究电极表面Co-N-C催化剂的分散性和电化学工艺参数对产H₂O₂机制与效能的影响，以石墨板为基底，Co-N-C催化剂为涂层制备石墨基高分散Co-N-C涂层电极。通过扫描电子显微镜、X线衍射、循环伏安扫描和X线光电子能谱等手段对制备的Co-N-C催化剂及涂层电极进行微观结构和电化学表征，改变石墨粉与Co-N-C的质量比来控制负载量，考察不同Co-N-C负载量涂层电极对O₂的催化还原活性和不同工艺条件下的产H₂O₂效能，并对影响机制进行深入探究。结果表明：Co-N-C催化剂被均匀负载到石墨板表面，其中Co-N-C-20（Co-N-C与石墨粉的质量比为1∶20）涂层电极具有较好的分散性和最高O₂的二电子还原催化活性。酸性条件、合适的电流密度和O₂曝气量有助于O₂的二电子还原反应生成H₂O₂,减少H₂O₂继续被还原和分解。在优化工艺条件下反应80 min, Co-N-C-20电极产H₂O₂的累积浓度达到291.3 mg/L,电流效率为52.66%。更多还原

【Abstract】 To study the effect of Co-N-C catalyst dispersion on the electrode surface and the effect of electrochemical process parameters on the mechanism and efficiency of H₂O₂ production, graphite-based highly dispersed Co-N-C coating electrodes were prepared with graphite plate as the substrate and Co-N-C catalyst as coating. The microstructure and electrochemical characterization of the prepared Co-N-C catalyst and coating electrodes were carried out by scanning electron microscopy, X-ray diffraction, cyclic voltammetry scanning and X-ray photoelectron spectroscopy. The Co-N-C loading was controlled by changing the mass ratio of graphite powder to Co-N-C, the catalytic reduction activity of the coated electrodes with different Co-N-C loadings on O₂ and the efficiency of H₂O₂ production under different process conditions were investigated, and the influence mechanism was further explored. Results showed that the Co-N-C catalyst was uniformly loaded on the surface of the graphite plate, and the Co-N-C-20 coated electrode（mass ratio of Co-N-C to graphite powder of 1∶20） had good dispersion and the best catalytic activity for two-electron reduction of O₂. Acid conditions, appropriate current density and O₂ aeration were helpful for the two-electron reduction of O₂ to generate H₂O₂, reducing the further reduction and decomposition of H₂O₂. After reaction for 80 min under the optimized conditions, the cumulative concentration of H₂O₂ produced by the Co-N-C-20 electrode reached 291.3 mg/L, and the current efficiency was 52.66%.更多还原