Features of Cyclic Voltammograms

The current is related to the flux across the electrode surface by Faraday s laws for a fixed concentration drop - bulk to zero - this flux is then 

Therefore, the rate of electron transfer for quasi-reversible kinetics does not increase with the swept potential as quickly as if A G is sufficiently low 

By contrast, the potential at which this limit occurs can be altered because a faster Db causes more efficient dispersion of the product from the electrode. Then further reaction is driven, i.e. the equilibrium is shifted according to Le Chateher s principle. So, a correspondingly faster reaction occurs at lower overpotentials. Therefore Db does affect the forward peak potential in an apparently electrocatalytic manner. 

Only the Faradaic current resulting from the electrolysis process varies linearly with c the capacitive current generally tends to depend on the total salt concentration which is dominated by the supporting electrolyte. Therefore the overall peak current, fpf, is a linear function of c but is not zero in the absence of a redox-active species since a capacitive current is stiU present. When interpreting experimental data it is important to carefidly choose a baseline from which the Faradaic current may be measured and hence allow analytically useful data to be obtained. 

Unlike chronoamperometry, exact solutions do not exist for cyclic voltammetry 

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A complete analysis of the effects of adsorption on the voltammetry is difficult given the number of different situations that can be found, mainly determined by the adsorption strength of the electroactive species, the time scale of the experiment and the electron transfer kinetics. The schematic in Figure 6.5 summarises some of the main features of cyclic voltammograms in the presence of adsorption of the electroactive species. For the sake of simplicity, the electron transfer processes are assumed to be fully reversible. 

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