Chang Byoung-Yong, Park Su-Moon
Department of Chemistry and Center for Integrated Molecular Systems, Pohang University of Science and Technology, Pohang, Gyeongbuk 790-784, Korea.
Anal Chem. 2006 Feb 15;78(4):1052-60. doi: 10.1021/ac051641l.
An integrated theory describing both faradaic and nonfaradaic currents obtained upon potential step at an electrified electrode/electrolyte interface has been developed based on equivalent circuits that had been used to explain electrochemical reactions and experimentally verified. The faradaic current is shown to consist of the mass transport-dependent and -independent parts, which is in general agreement with the expression previously derived from the diffusion equations. The decay of the capacitive current is determined by the time constant represented by the product of the resistance obtained from the parallel connection of the solution and polarization resistances and the double layer capacitance; this is not consistent with the current understanding of the capacitive current decay, which takes into account the double layer capacitance and the solution resistance only. Many insights into the electron-transfer reactions are discussed based on the interpretation of impedance representation of the system, which would not have been possible without the present theory.
基于曾用于解释电化学反应并经实验验证的等效电路，已开发出一种综合理论，该理论描述了在带电电极/电解质界面进行电位阶跃时所获得的法拉第电流和非法拉第电流。结果表明，法拉第电流由质量传输相关部分和非相关部分组成，这与先前从扩散方程得出的表达式总体一致。电容性电流的衰减由时间常数决定，该时间常数由溶液电阻和极化电阻并联所得电阻与双层电容的乘积表示；这与当前对电容性电流衰减的理解不一致，后者仅考虑双层电容和溶液电阻。基于对该系统阻抗表示的解释，讨论了许多关于电子转移反应的见解，若没有本理论，这些见解是不可能获得的。
