物理化学学报 >> 1985, Vol. 1 >> Issue (04): 357-364.doi: 10.3866/PKU.WHXB19850410

研究论文 上一篇    下一篇

锌在玻璃碳上的电化学成核机理

吴辉煌; 许书楷; 周绍民   

  1. 厦门大学 化学系 物理化学研究所
  • 收稿日期:1984-12-10 修回日期:1985-03-19 发布日期:1985-08-15

ELECTROCHEMICAL NUCLEATION OF ZINC ON VITREOUS CARBON

Wu Huihuang; Xu Shukai; Zhou Shaomin   

  1. Department of Chemistry, Xiamen University Insititute of Physical Chemistry, Xiamen University
  • Received:1984-12-10 Revised:1985-03-19 Published:1985-08-15

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摘要： 线性扫描伏安法和电位阶跃法被用来研究氯化钾镀锌溶液中锌在玻璃碳上电结晶的初期阶段。发现锌在该基体上的沉积没有经历UPD过程。在本实验条件下, 成熟晶核的生长受溶液中锌离子的扩散所控制, 而晶核形成的机理依有无添加剂存在而异。通过分析恒电位暂态, 求出锌离子的扩散系数D, 以及不同过电位η下的成核速度常数A和晶核数密度N_0。A和η的关系表明“原子模型”比经典的成核模型更适合于本研究体系。N_0与η的经验关系式由曲线拟合而得。本文着重讨论了过电位和添加剂对成核作用的影响。

Abstract: The initial stages of the electrocrystallization of zinc onto vitreous carbon from chloride zinc-plating solutions were investigated using linear sweep voltammetry and potential step method. It was observed that the deposition of zinc on the substrate did not undergo the UPD process before its overpotential deposition occurred. In the experimental conditions, the growth of the mature nuclei is controlled by the diffusion of the depositing ions to the electrode. The mechanism of nucleation evidently depends on the presence of the additives used, i.e., 3D progressive in the solutions with the additives, instead, 3D instantaneous without them.
By analyzing of the potentiostatic transients, the D value of the depositing zinc ions was estimated, and the nucleation rate constants A at different overpotentials η were obtained. lgA was found to be in direct proportion to η rather than η~(-2), which means that the so-called atomistic model is better than the classical model of nucleation in the present system.
Nuclear ...