Voltammetry peak splitting

Voltammetry of zeolite-associated electroactive species in contact with size-excluded electrolyte counteractions produces single signals, whereas in the presence of less size-excluded counteractions, peak splitting frequently appears. 

Using a computer, carry out simulations of cyclic voltammetry for a quasireversible system. Let = 50 and Dm = 0.45, Take a = 0.5 and let the diffusion coefficients of the oxidized and reduced forms be equal. Cast your dimensionless intrinsic rate parameter in terms of the function ij/ defined in (6.5.5), and carry out calculations for ip = 20, I, and 0.1. Compare the peak splittings in your simulated voltammograms with the values in Table 6.5.2. 

Other redox-active polyelectrolyte films were prepared from ferrocene-derivatized polly(allylamine) and poly(vinyl pyridine) as well as an osmium complex of poly(vinyl pyridine) [44-46]. These films were synthesized to mediate electron transfer between the electrode and a charged enzyme that was a constituent of the polyelectrolyte film. In the case of ferrocene-derivatized poly(allylamine) or polyfvinyl pyridine), cyclic voltammetry of the bound ferrocene moiety showed small peak splittings (<50 mV at a scan rate of 50 and 20 mV s respectively) [45, 46). The amount of electroactive material increased with the number of deposited layers, but the first layer contained significantly more electroactive ferrocene than the later layers in the poly(allylamine) system [46]. 

The electronic absorption spectrum of 190 exhibits a split Q band with peaks at 632 and 554 nm and the Soret band is found at 338 nm. Additionally, a peak is observed at 427 nm and assigned to O-pz, n-ji transition. The electrochemical properties of 189 and 190 have been studied by cyclic voltammetry in CH2C12. Compound 190 exhibits one reversible oxidation at Em = +0.73 V (vs Fc+/Fc) (11). 

Due to the similarity with surface electrode processes, a quasireversible reaction in thin-film voltammetry exhibits a quasireversible maximum and splitting of the net peak. The reasons causing these voltammetric features are the same as for surface... 

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