Voltammetry Involving Amalgam Formation and Anodic Stripping in Weakly Supported Media: Theory and Experiment

Abstract

The voltammetric behavior of the Tl(I)/Tl(Hg) redox couple at a small mercury hemisphere (45 µm radius) is theoretically and experimentally investigated in the presence of various concentrations of supporting electrolyte, covering the range between "self-supported" (no electrolyte) to "fully supported" (very large excess of supporting electrolyte). A theoretical model is described, implementing the Nernst-Planck-Poisson equations, to account for both diffusional and migrational contributions to the mass transport, as well as for the potential distribution in solution. The model accurately reproduces the experimental results and then is used to predict the cathodic and anodic peak potentials and intensities for a wide range of supporting conditions, potential sweep rates, and electrode sizes. The influence of diffusion (linear vs spherical, semi-infinite vs finite), electrode size, and potential drop in solution are discussed in light of the theoretical and experimental results.

Cyclic Voltammetry in the Absence of Excess Supporting Electrolyte Offers Extra Kinetic and Mechanistic Insights: Comproportionation of Anthraquinone and the Anthraquinone Dianion in Acetonitrile

“…[5,6,[12][13][14][15][16] Most publications to date have only considered systems at steady state; this was the case for the EE studies (E stands for an electron-transfer step) noted above. [17] We have developed a simulation system for transient cyclic voltammetry which has been applied successfully to E processes [18,19] and admits extension to any mechanism. [17] We have developed a simulation system for transient cyclic voltammetry which has been applied successfully to E processes [18,19] and admits extension to any mechanism.…”

Cyclic Voltammetry in the Absence of Excess Supporting Electrolyte Offers Extra Kinetic and Mechanistic Insights: Comproportionation of Anthraquinone and the Anthraquinone Dianion in Acetonitrile

“…[8][9][10][11] Work under transient conditions has been done exclusively for the E mechanism. [17] We have developed a simulation system for transient cyclic voltammetry which has been applied successfully to E processes [18,19] and admits extension to any mechanism. The simulation solves the dynamic Nernst-Planck-Poisson equations simultaneously for all chemical species and for potential, subject to a zerofield approximation.…”

Aptamer‐Based Turn‐On Detection of Thrombin in Biological Fluids Based on Efficient Phosphorescence Energy Transfer from Mn‐Doped ZnS Quantum Dots to Carbon Nanodots

“…Work under transient conditions has been done exclusively for the E mechanism 17. We have developed a simulation system for transient cyclic voltammetry which has been applied successfully to E processes18, 19 and admits extension to any mechanism. The simulation solves the dynamic Nernst–Planck–Poisson equations simultaneously for all chemical species and for potential, subject to a zero‐field approximation 20.…”