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本文试图进一步从动力学方面证明恒电位下的锌电极在KOH溶液中阳极惰化时,阳极溶解电流随时间而缓慢下降是由于“表面相变”所引起。用恒电位法测取了锌电极在不同浓度的KOH溶液中电流对时间的曲线。实验结果与推导的动力学方程式相符,表明在恒电位惰化条件下,锌电极表面上最初形成的[Zn(OH)_2]_(ad)在OH~-参预下徐缓地转变为较不易溶的[ZnO]_(ad),因而导致阳极溶解电流的下降。这一表面相变过程可表示如下:
In this paper, we try to further prove that the anodic dissolution current decreases slowly with time due to “surface phase change” when the zinc electrode under potentiostatic potentials is anodized in KOH solution. The potentiometric method was used to measure the current-to-time curves of zinc electrodes in different concentrations of KOH solution. The experimental results are consistent with the derived kinetic equations, indicating that the initial formation of [Zn (OH) 2] _ (ad) on the surface of zinc electrode slowly changes to less soluble under the preferential OH ~ Of [ZnO] _ (ad), resulting in a decrease in anodic dissolution current. This surface phase change process can be expressed as follows: