Theory of square wave voltammetry for kinetic systems

Abstract

The theoretical response for the application of square wave voltammetry to systems complicated by electrode kinetics or by preceding, following, or catalytic homogeneous chemical reactions Is presented. Experimentally measurable parameters such as peak shifts, heights, and widths are calculated and plotted as functions of the appropriate rate constants. These curves are characteristic of the electrode process and provide a basis for the extraction of kinetic Information from the fast scan square wave experiment.

Scanning Electrochemical Microscopy: Approach Curves for Sphere-Cap Scanning Electrochemical Microscopy Tips

“…SCV belongs to the family of pulsed voltammetric methods developed to enhance detection limits and minimize distortion from background processes. [3][4][5][6][7] In its basic form successive chronoamperograms are recorded after stepping the potential from a rest value where no redox process occurs at an appreciable rate to values where the target Faradaic process takes place. The resulting transients, Figure 1a In this study we demonstrate how applying SCV to microdisk electrodes offers new opportunities to exploit the unique properties of microelectrodes, particularly at short times.…”

A new rapid and simple method to determine the kinetics of electrode reactions of biologically relevant compounds from the half-peak width of the square-wave voltammograms

“…By k s we assign the standard rate constant of electron transfer (k s is given in cm s − 1 for reaction from the dissolved state and in s − 1 for surface redox reactions), while D (cm 2 s − 1 ) is the common diffusion coefficient of both species of the dissolved redox couple. Detailed studies of the features of simple surface redox reaction and redox reaction from the dissolved state related to the influence of the kinetic parameter K, E sw , α, and n under conditions of square-wave voltammetry can be found elsewhere [3,12,13]. In this work, we focus on the influence of the kinetic parameters of the electron transfer reaction on the half-peak widths of theoretical square-wave voltammograms.…”

“…The half-peak width of the SW voltammograms of a redox reaction from dissolved state (at constant temperature) is influenced by the normalized square-wave amplitude nE sw , the electron transfer coefficient α, and the dimensionless kinetic parameter K. The sensitivity of the half-peak width to the number of exchanged electrons n and the electron transfer coefficient α has been briefly mentioned in the work of O'Dea and Osteryoungs [12,13].…”

“…Quantifying the strengths of interactions between biologically important compounds, and revealing the mechanistic pathways of many proteins and enzymes attached to the surface of the working electrodes are just some of the new exciting fields in which square-wave voltammetry has been explored as a simple and powerful tool [2,3,[8][9][10][11]. The SWV technique allows accurate quantification of various kinetic and thermodynamic parameters connected to electron transfer reactions of many redox-active compounds in very elegant ways [1][2][3]12,13]. Considering the electrode reaction of a single compound, the main physical parameters that describe the electron transfer reaction between the electrode and the investigated compound are: the standard redox potential E°(which is tightly connected to the magnitude of the energetic barrier of electron transfer), the number of exchanged electrons involved in the elementary act of electrochemical transformation n, the electron transfer coefficient α (i.e.…”

“…The kinetic characterization with the square-wave voltammetry has become particularly interesting due to the simplicity and accuracy of the developed methods [2,3,[14][15][16][17][18][19][20][21][22][23][24]. While the peak potentials (and peak-to-peak separation) as a function of the SW frequency have commonly been used to determine the kinetics of redox reactions from the dissolved state [1][2][3]13], the phenomenon of "quasireversible maximum" (based on the peak-current measurements) has emerged as a simple and viable method to determine kinetic parameters of surface-confined redox reactions [3,12,[19][20][21][22][23][24]. In the present paper, we present theoretical results that are related to the measuring of kinetic parameters of the electron transfer reactions, in which the half-peak width of the net square-wave voltammograms is the main studied feature.…”