engleski

Characterization of electrode processes by cyclic square-wave voltammetry

A theoretical analysis of reversible and kinetically controlled electrode reactions, as well as electrode processes controlled by kinetics of homogeneous chemical reaction, under conditions of cyclic square-wave voltammetry (CSWV) is presented. The cyclic square-wave voltammetry enables faster and more complete characterization of the electrode processes, comparing with classical square-wave voltammetry. Electron transfer coefficients (α and β), as well as the standard rate constant of a simple electrode reaction Ox + ne = Red, can be determined from the slopes of linear dependences of cathodic and anodic net peak potentials (Ep) on the logarithm of frequency. Furthermore, the rate constant of follow-up chemical reaction (kf) can be estimated from the linear ependence of anodic to cathodic net peak currents ratio (∆ip, a/∆ip, c) on log (f). The criteria for recognition of electrode mechanisms are given.

Cyclic square-wave voltammetry; excitation signal; kinetics; theory

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