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本文在ChCl/CrCl3.6H2O离子溶液体系中,采用循环伏安法和恒电位阶跃法研究了Cr(Ⅲ)在玻碳电极上的电化学成核机理。研究结果表明,Cr(Ⅲ)的电化学成核机理是三维成核并与过电位有关。当过电位较小时,Cr(Ⅲ)的电结晶过程为三维连续成核,其扩散系数为(2.56±0.33)×10-11m2/s。当过电位较大时,Cr(Ⅲ)的电结晶过程趋向于三维瞬时成核过程,其扩散系数和晶核数密度均与过电位无关,分别为(3.04±0.3)×10-11m2/s和(4.47±0.05)×1011/m2。两种成核方式的法向生长速率常数均与过电位成线性关系,晶体法向的生长没有受到任何阻滞。
In this paper, the electrochemical nucleation mechanism of Cr (Ⅲ) on glassy carbon electrode was studied by cyclic voltammetry and potentiostatic step method in ChCl / CrCl3.6H2O ionic solution system. The results show that the electrochemical nucleation mechanism of Cr (Ⅲ) is three-dimensional nucleation and is related to overpotential. When the overpotential is small, the electrocrystallization of Cr (Ⅲ) is three-dimensional continuous nucleation with a diffusion coefficient of (2.56 ± 0.33) × 10-11m2 / s. When the overpotential is large, the electrocrystallization process of Cr (Ⅲ) tends to three-dimensional transient nucleation process, and its diffusion coefficient and nuclei density are independent of overpotential (3.04 ± 0.3) × 10-11m2 / s And (4.47 ± 0.05) × 1011 / m2. The normal growth rate constants of both nucleation modes are linear with overpotential, and the normal growth of the crystal is not affected by any retardation.