Principles of Electrochemistry

Cyclic voltammetry (CV) is a widely used electrochemical technique for analyzing the charge transfer of a redox-active specie during a linearly cycled potential sweep. It provides valuable information about interfacial processes, redox thermodynamics, diffusion coefficients, electrode surface properties, and charge-transfer kinetics. However, despite its popularity, CV is often misunderstood due to the simultaneous occurrence of multiple processes, complicating the interpretation of voltammograms. Let's consider the following redox reaction: \begin{equation} Fe^{2+}\underset{k_b}{\overset{k_f}{\rightleftharpoons}}Fe^{3+}\end{equation} The rate of this reaction can be described phenomenologically as: \begin{equation}r=k_f[Fe^{2+}]-k_b[Fe^{3+}]\end{equation} In the classical chemical kinetics, the kinetic constant depends exponentially with temperature according to the Arrhenius equation: \begin{equation}k=A\exp\left(-\frac{Ea}{RT}\right)\end{equation} This equation tells us that the