AC IMPEDANCE OF FARADAIC REACTIONS INVOLVING ELECTROSORBED INTERMEDIATES - EXAMINATION OF CONDITIONS LEADING TO PSEUDOINDUCTIVE BEHAVIOR REPRESENTED IN 3-DIMENSIONAL IMPEDANCE SPECTROSCOPY DIAGRAMS

The mechanistic significance of pseudoinductive behavior of the electrode impedance of Faradaic reactions involving one and two adsorbed intermediates is examined. Simulated impedance spectra are represented in three-dimensional plots: a potential, E, axis is introduced into the complex plane representation of the impedance behavior since determination of the potential dependence of the electrode impedance should be one of the principal aspects of experimental characterization of most reactions by impedance spectroscopy at potentials substantially displaced from the equilibrium value. This potential dependence of the impedance is one of the major considerations of the present paper and arises physically, from the usual potential dependence of the Faradaic resistance together with that of coverage by any Faradaically generated adsorbed intermediates that are involved in the reaction mechanism. The effects of a combination of the potential dependent Faradaic impedance with that of the double-layer capacitance, always present, are considered as a function of frequency.