镍纳米线电极的交流阻抗研究

AC Impedance of a Nickel Nanowire Electrode

用交流阻抗法研究了一种新型电极——镍纳米线电极在碱性溶液中的电化学行为 ,给出了相应的等效电路和拟合结果 .实验结果表明 ,外加电位对电极表面化学反应速度和类型有显著影响 .在外加电位不高时 ,Ni( )氧化成 Ni( )的电化学过程随着电位的升高而明显加速 ;当外加电位高于 0 .40 V以后 ,电极表面同时发生电化学析氧反应 .相同条件下 。

Electrochemical impedance spectra of a nickel nanowire electrode at different applied potentials and their fitting results are given. The experimental results revealed that the electro chemical processes on the surface of the electrode were apparently influenced by the applied potentials. The electrochemical oxidation rate of Ni(Ⅱ) to Ni(Ⅲ) increased remarkably with the applied potential at a range of 0 10~0 40 V( vs .Ag/AgCl(1 mol/L KCl)). When the applied potential was higher than 0 4 V, the oxygen evolution reaction occurred simultaneously. The AC impedance measurements on a nickel bulk electrode and a nickel nanowire electrode under the same conditions showed the latter had much greater electrochemical activity and much faster reaction rate in the surface processes.