Combining Impedance Spectroscopy with Cyclic Voltammetry:  Measurement and Analysis of Kinetic Parameters for Faradaic and Nonfaradaic Reactions on Thin-Film Gold

• Published in: Analytical chemistry (Washington) 2006-06, Vol.78 (11), p.3723-3729
• Main Authors: Pettit, C. M, Goonetilleke, P. C, Sulyma, C. M, Roy, D
• Format: Article
• Language: English
• Subjects: Analytical chemistry; Chemistry; Electrochemical methods; Exact sciences and technology; Gold; Gold - chemistry; Kinetics; Oxidation-Reduction; Spectrometric and optical methods; Spectrum Analysis; Thin films
• ISSN: 0003-2700; 1520-6882
• DOI: 10.1021/ac052157l

The technique of time-resolved impedance spectroscopy can be combined with dc cyclic voltammetry (CV) to study mechanisms and kinetics of electrochemical reactions at solid−liquid interfaces. Utilization of these techniques in a combined framework, however, is based on a number of specific considerations of measurement procedures and data analysis. The present work discusses certain essential elements of this topic, focusing primarily on the analysis of time-resolved impedance spectra where interdependent dc and ac effects of parallel faradaic and nonfaradaic reactions are present under potentiodynamic conditions. A thin gold film is used as a model experimental system where oxidation and reduction of the sample surface is voltage-controlled both in the presence and in the absence of specifically adsorbing Cl- ions in neutral background electrolytes of NaF. Impedance spectra are recorded under transient conditions of CV, and kinetic parameters based on electrode-equivalent circuit models are obtained as functions of CV scans.