Diagnostic Criteria for Identifying Electrode Reaction Mechanisms By Cyclic Square Wave Voltammetry

This presentation will demonstrate the utility of cyclic square wave voltammetry for determining the mechanism of an electrode reaction.  The impact of theoretical and empirical parameters on the shape of the current-voltage curve was evaluated computationally. Simulations were conducted for single and consecutive reversible electron transfer reactions as well as those that are kinetically controlled and/or chemically coupled.  The simulation involved systematic variation in alpha, k⁰, K_eq, k_f + k_b, amplitude, increment, period and switching potential. Trends in peak potentials, currents, and widths with variation in each of these parameters were elucidated.  From these trends, diagnostic criteria for assigning each mechanism was identified and, in many cases, experimentally verified. Our goal is to facilitate the use of cyclic square wave voltammetry as a mechanistic tool by both experts and non-experts in electrochemistry.  These criteria enable accurate diagnosis of the electrode reaction mechanism and measurement of pertinent kinetic and thermodynamic quantities.