计时电量法求NiCl_2(bpy)_3在DMF中的扩散系数和速率常数

Diffusion Coefficients and Rate Constants of NiCl_2(bpy)_3 in DMF Determined by Chronocoulometry

讨论了NiCl2(bpy)3(bpy:2,2-联吡啶)在DMF中的电化学行为.控制电位使电极过程处于扩散控制下,采用计时电量法求得了29℃时NiCl2(bpy)3在DMF中的扩散系数为5.99×10-6cm2·s-1,不同温度下的扩散系数随温度升高而增大.选择合适的电极电位,使电极过程处于扩散和电化学混合控制下,采用计时电量法求得了不同电极电位下的反应速率常数kf,以及不同温度下的标准速率常数k0,求得了表观活化能为14.4kJ·mol-1.

The electrochemical characteristic of NiCl2（bpy）3 at glassy carbon electrode in DMF has been investigated by using cyclic voltammetry. Chronocoulometry was employed to determine the diffusion coefficients and the rate constants （kf and k^0）. The CV results imply that the redox reaction of NiCl2（bpy）3 at glassy carbon electrode is quasi-reversible. The diffusion coefficient increased with the increase of temperature between 302.15 K and 334.15 K. The forward rate constants （kf） at different potentials and standard rate constants （k^0） at different temperatures were also obtained by analysis of charge-time data. According to the slope of lnk^0 against T^-1, the activation energy （Ea） of the electron transfer was 14.4 kJ·mol^-1.