采用涂附法制备了石墨镀银电极。用配有EDS的扫描电子显微镜(FE-SEM)对石墨镀银电极表面结构进行了表征,以石墨镀银电极和石墨电极为工作电极,采用线性扫描法研究了硫化黑在NaOH溶液中的电化学还原行为,探讨了溶液pH值对硫化黑2BR2000电还原反应的影响。实验结果表明:用涂附法制备得到的石墨镀银电极表面分布了大量金属银颗粒,该石墨镀银电极对硫化黑2BR200%的还原反应显示了很高的电催化活性,其电催化活性高于石墨电极;电解液的pH值越大,硫化黑的电还原反应就越容易。在恒电流电解中,以镀银石墨电极为阴极,电流密度为6.25mA·cm^-2,反应温度为(27±2)℃时,硫化黑的电解实验的电流效率可达92.2%。
Silver-plated graphite electrodes were prepared by the absorption method and its surface structure was characterized by SEM assembled with energy dispersive spectrometer. The electrochemical behavior of Sulfur Black 2BR 200% on graphite and silver-plated graphite was studied with linear sweep voltammograms. Experimental results showed that metal silver was successfully coated on the surface of graphite and silver-plated graphite electrode gave higher current and showed better catalytic property for the reduction of Sulfur Black 2BR 200%. In addition, the rate of reduction reaction of Sulfur Black increased with increasing pH of electrolyte. The electrolysis experiments were performed by using graphite and silver-plated graphite cathodes respectively. Excellent current efficiency (92.2%) was obtained in the following reaction condition: silver-plated graphite used as cathode, temperature (27±2)℃, current density 6.25 mA·cm^-2, pH of electrolyte 14.