钯镍合金在玻碳电极上电结晶机理

Electrocrystallization of Pd-Ni Alloys on Glassy Carbon Electrode

在钯镍合金电解液中,采用循环伏安和计时安培实验方法,运用Scharifker和Hills模型、Heerman和Tarallo模型揭示钯镍合金的成核机理.结果表明,钯镍合金在玻碳电极上发生成核过程.Scharifker和Hills模型分析表明,钯镍合金更符合扩散控制下的三维生长的连续成核机理.借助于Heerman和Tarallo模型,拟合得到钯镍合金的成核和生长的动力学参数.拟合结果显示,电位阶跃从-0.85V负移至-0.92V(vsSCE),钯镍合金在玻碳电极上的成核速率从0.83s-1增加到7.71s-1,成核密度数从2.77×104cm-2提高至7.09×104cm-2.

Using the Scharifker and Hills model and Heerman and Tarallo model, cyclic voltammetry and chronoamperometry were used to study the nucleation mechanism upon the electrodeposition of a Pd-Ni alloy from an electrolyte. The results show that the electrodeposition of the Pd-Ni alloy onto glassy carbon electrode consisted of nucleation and growth, and the nucleation process according to the Scharifker and Hills model follows three dimension-progressive nucleation, which is controlled by the diffusion of the electroactive species. By applying the Heerman and Tarallo model, the kinetic parameters associated with the crystal nucleation and growth processes were obtained. The nucleation rate constant and the density of active nucleation sites increased from 0.83 to 7.71 s-1 and from 2.77×104 to 7.09×104 cm-2, respectively, as the step potential was changed from -0.85 to -0.92 V （vs SCE）.