Ni(Ⅱ)离子在两种离子液体中的电化学行为

Electrochemical behavior of Ni(Ⅱ) in different ionic liquids

  • 摘要: 在离子液体氯化1-丁基-3-甲基咪唑-丙三醇(BMIC-GL)和1-丁基-3-甲基咪唑二氰胺盐(BMIMDCA)中加入NiCl2后,研究了Ni(Ⅱ)离子的电化学行为。循环伏安测试结果表明,Ni(Ⅱ)离子在BMIMDCA-NiCl2和BMIC-GL-NiCl2的起始还原电位分别为-0.55 V和-0.65 V,说明Ni(Ⅱ)离子在BMIMDCA-NiCl2中更易被还原。Ni(Ⅱ)离子在两种离子液体中的还原均是受扩散控制的准可逆过程。通过计算得出Ni(Ⅱ)离子在BMIC-GL-NiCl2中的扩散系数(8.92×10-7 cm2/s)大于其在BMIMDCA-NiCl2中的扩散系数(2.94×10-7 cm2/s)。通过计时电流暂态分析得出,在BMIC-GL-NiCl2和BMIMDCA-NiCl2离子液体中,在玻碳电极上电沉积Ni的反应分别符合三维瞬时形核机理和三维连续形核机理。

     

    Abstract: Abstract: The electrochemical behaviors of Ni(Ⅱ) with the addition of NiCl2 to a 1-butyl-3-methylimidazolium chloride-glycerine (BMIC-GL) ionic liquid and a 1-butyl-3-methylimidazolium dicyanamide (BMIMDCA) ionic liquid were studied. Voltammetry analysis showed that the reduction potential of Ni(Ⅱ) in BMIMDCA-NiCl2 ionic liquids was more positive than that in the BMIC-GL-NiCl2 ionic liquid, indicating that the reduction of Ni(Ⅱ) in BMIMDCA-NiCl2 was easier. In addition, the reduction reaction of Ni(Ⅱ) in both ionic liquids was a quasi-reversible process controlled by diffusion, but the diffusion coefficient in BMIC-GL-NiCl2 was 8.92×10-7 cm2/s, which was significantly greater than that in BMIMDCA-NiCl2 (2.94×10-7 cm2/s). Current-time transient analysis showed that the electrodeposition of nickel on a glassy carbon electrode in BMIC-GL-NiCl2 ionic liquid followed the three-dimensional instantaneous nucleation mechanism, while that in BMIMDCA-NiCl2 conformed to the three-dimensional progressive nucleation mechanism.

     

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