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

Asymmetric Marcus theory: Application to electrode kinetics

“…On the other hand, b remarkably affects the relative heights of the oxidative and reductive peak currents. [24][25][26][27]29]. For these systems, the reductive and oxidative experimental peaks could no be fitted with the symmetric MH model: typically forcing the fit led to the magnitude of one of the peaks being overestimated, whilst underestimating the other one.…”

“…In recent works, we have critically evaluated the ability of the above approach to describe quantitatively the response of several solution-phase systems in voltammetric techniques [23][24][25][26][27][28][29]. The electroreductions of 2-nitropropane and 2-methyl-2-nitropropane in acetonitrile [24,26,27], of cyclooctatetraene in dimethylsulfoxide [25] and of europium (III) in water [26,29], were studied using cyclic, square wave and differential multipulse voltammetries.…”

“…The electroreductions of 2-nitropropane and 2-methyl-2-nitropropane in acetonitrile [24,26,27], of cyclooctatetraene in dimethylsulfoxide [25] and of europium (III) in water [26,29], were studied using cyclic, square wave and differential multipulse voltammetries. In all cases the voltammograms could not be fitted satisfactorily with the symmetric MH kinetic model.…”

“…Turning to redox couples in solution, the application of the MH model has been more restricted due to complications arising from the masking of kinetics by mass transport. Recently, the application of the MH formalism has been tackled by several authors [21][22][23][24][25][26][27][28][29]. Among them, Compton and coworkers have carried out a critical analysis of the MH model by studying a variety of redox couples using cyclic voltammetry, square wave voltammetry and differential multi pulse voltammetry with independent characterization of the diffusion coefficients of both species of the redox couple.…”

“…Among them, Compton and coworkers have carried out a critical analysis of the MH model by studying a variety of redox couples using cyclic voltammetry, square wave voltammetry and differential multi pulse voltammetry with independent characterization of the diffusion coefficients of both species of the redox couple. The use of microhemispherical electrodes allowed rigorous modelling and elimination of possible ohmic drop effects [25][26][27]29]. The results obtained show that MH in its symmetric form is not able to quantitatively describe the voltammetric response of systems for which transfer coefficients different from 0.5 have been reported.…”