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Exploring Cyclic Voltammetry: Unraveling the Dynamics of Chemical Reactions Coupled with Electron Transfer

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In many cases, electrochecial systems are more complex than a simple interfacial electron transfer and may involve coupled chemical reactions. The presence of homogeneous chemical reactions in conjuction with the electrode process can significantly impact the electrochemical response of the system. In this blog, we will explore the scenario where a homogeneous first-order reaction is followed by an interfacial electron transfer, as described by the following sequence reactions: \begin{equation} A\underset{k_b}{\overset{k_f}{\rightleftharpoons}}B + e^- \end{equation} \begin{equation} B + H^+\overset{k_1}{\rightarrow}BH \end{equation} Here k 1   is the homogeneous rate constant, and the species BH is considered electroinactive within the potential region under study. Additionally, we assume that the proton concentration is much higher than that of species B , allowing the homogeneous reaction to be approximated as a first-order reaction. Examples of this type of mechanism are the oxidat
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Understanding cyclic voltammetry: Electron Transfer Mechanism

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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
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