Quantitative Voltammetry in Weakly Supported Media: Effects of the Applied Overpotential and Supporting Electrolyte Concentration on the One Electron Oxidation of Ferrocene in Acetonitrile

Abstract

Chronoamperometry is reported on the one electron oxidation of 3 mM ferrocene in acetonitrile using a 300 ± 5 μm radius gold hemisphere electrode. Varying concentrations of supporting electrolyte (tetra-n-butylammonium perchlorate) are used ranging from the fully supported (100 mM) to the almost completely unsupported (0.1 mM). The response is simulated using the Nernst−Plank−Poisson system of equations and excellent agreement between theory and experiment noted, so vindicating a recent theory (J. Phys. Chem. C, 2008, 112, 13716) for voltammetry in weakly supported media.

Theory of linear sweep voltammetry with diffuse charge: Unsupported electrolytes, thin films, and leaky membranes

“…The physical difference is that electromigration is included in the latter [i.e., Eq. (15) the voltammogram for low support has been well documented in the experimental literature (see [55,63,64,70,72], among others).…”

“…The additional species in their work are sometimes neutral [71,72] and sometimes charged [66,70], depending on the reaction being modeled. Modeling of uncharged and supporting ionic species has also been a feature of other models in the literature [58][59][60].…”

Voltammetry in the absence of excess supporting electrolyte – ECE-DISP1 reactions: The electrochemical reduction of 2-nitrobromobenzene in acetonitrile solvent

“…This grid corresponds to that used in previous work [32][33][34]17], with a region of extremely dense regular grid spacing close to the electrode that expands proportionally to R beyond some characteristic switching point R s . Mathematically, the R position of a point R j is defined as:…”

Experimental comparison of the Butler–Volmer and Marcus–Hush–Chidsey formalisms of electrode kinetics: The reduction of cyclooctatetraene at mercury hemispherical electrodes via cyclic and square wave voltammetries

“…Moreover, due to its one dimensional symmetry, simulation of the electrochemical response at spherical electrodes is simpler, faster and more accurate than at the more conventional microdiscs. Hence, the inference of ohmic-drop effects can be easily evaluated in order to discard their influence in the experimental results [30][31][32].…”