Zn(Ⅱ)/Zn交换反应速度常数的交流阻抗法测定

DETERMINATION OF THE RATE CONSTANT OF THE Zn ( I )/Zn EXCHANGE REACTION THROUGH AC IMPEDANCE SPECTROSCOPY

本文应用交流胆抗法测定Zn(Ⅱ)/Zn体系在微酸性硫酸盐溶液中的交换反应速度常数.根据电荷转移电阻(R_(ct))计算得交换反应速度常数(k)为(3.1±0.5)×10^(-5)ms^(-1).k值与转速无关,表明Zn^(2+)离子从本体溶液向电极表面的扩散不参与界面上的交换速度过程.

The rate constant of the Zu (II)/Zn exchange reaction in slightly acidic sulfate solution has been determined through AC impedance spectroscopy. On the basis of Rct derived from Z'/ 1/2 plot, the rate constant is calculated to be ( 3.1±0.5 ) 10-5 ms-1, which is independent of the rotation speed. This indicates that the diffusion of Zn2+ from the bulk solution to electrode surface is not involved in the exchange process.