Cyclic Voltammetry Simulations with DigiSim Software: An Upper-Level Undergraduate Experiment

Abstract

An upper-division undergraduate chemistry experiment is described which utilizes DigiSim software to simulate cyclic voltammetry (CV). Four mechanisms were studied: a reversible electron transfer with no subsequent or proceeding chemical reactions, a reversible electron transfer followed by a reversible chemical reaction, a reversible chemical reaction followed by a reversible electron transfer, and a reversible electron transfer followed by a reversible chemical reaction followed by a reversible electron transfer. The experiment concludes with a student discussion of three journal articles that contain CV data. In addition to introducing students to the theory of CV, the experiment also reinforces the physical chemistry concepts of equilibrium and rate of reaction. Thus, it is suitable for a physical chemistry, instrumental analysis, or integrated/ interdisciplinary laboratory experiment.

Interconvertible Living Radical and Cationic Polymerization using a Dual Photoelectrochemical Catalyst

“…The reversibility of the voltammograms suggests the long-lived feature of PTH •+ . Full analysis of the formal reduction potential of PTH ( E f 0 = 0.226 V vs Fc + |Fc), and the diffusion coefficient ( D PTH = 2.28 × 10 –5 cm 2 s –1 ) was done by fitting the experimental results to the Randles–Sevcik semi-infinite diffusion model (see Figure S2 and discussion within) . Of note, irreversible oxidation of CTA 1 (Figure b, green trace, and Figure S2) on the glassy carbon electrode is seen only at higher potentials ( E p = 0.938 V vs Fc + |Fc).…”

“…Full analysis of the formal reduction potential of PTH (E f 0 = 0.226 V vs Fc + |Fc), and the diffusion coefficient (D PTH = 2.28 × 10 −5 cm 2 s −1 ) was done by fitting the experimental results to the Randles−Sevcik semi-infinite diffusion model (see Figure S2 and discussion within). 32 Of note, irreversible oxidation of CTA 1 (Figure 2b, green trace, and Figure S2) on the glassy carbon electrode is seen only at higher potentials (E p = 0.938 V vs Fc + |Fc). These results demonstrate that PTH will be preferentially oxidized over CTA 1 on the electrode surface, supporting that it can work as a mediator to oxidize CTA 1 in solutions.…”

Why Is Voltammetric Current Scan Rate Dependent? Representation of a Mathematically Dense Concept Using Conceptual Thinking

“…The adjustable timescale, over several orders of magnitude, makes CV a unique technique for kinetic study of the electrode reactions and chemical reactions involving electron transfer . A variety of diagnostic criteria were established for reaction investigation by CV, − the majority of which rely on peak height analysis at different scan rates. − However, a prerequisite of all these analyses is understanding the scan rate dependence of peak current for the basic electrode reactions that involve only electron transfer. The scan rate dependence of voltammetric current is described by the Randles–Ševčík equation (at 25 °C) − where n is the number of electrons, A is the electrode surface area (cm 2 ), D and C bulk are the diffusion coefficient (cm 2 /s) and the concentration (mol/cm 3 ), respectively, of redox active species, and ν is the scan rate of the voltammetric experiment (V/s).…”

Deriving the Turnover Frequency of Aminoxyl-Catalyzed Alcohol Oxidation by Chronoamperometry: An Introduction to Organic Electrocatalysis

“…Recent advances in the electrosynthesis of organic compounds demonstrate that electrochemistry is a powerful tool to access unique reactivity and investigate complex mechanisms. − Investigation of these redox reactions and their coupled chemical reactions can play a valuable role in improving electrochemical reactions and chemical reactions that involve electron transfer and/or redox steps . Cyclic voltammetry (CV) is the most widely used electrochemical technique for studying electrode processes. − The flexible time window and forward and reverse scans of CV make it a powerful technique to study the mechanism of reactions that occur at an electrode surface; however, extracting quantitative information from CV data can be complicated. , Chronoamperometry (CA) is another standard electrochemical technique for understanding electrode reaction processes . Although CA data contain less mechanistic information than CV data, the former can be more straightforward to analyze than CV data to obtain quantitative information from electrochemical processes .…”