Other Voltammetric Techniques Chronoamperometry

The most useful equation in chronoamperometry is the Cottrell equation, which describes the observed current (planar electrode of infinite size) at any time following a large forward potential step in a reversible redox reaction (or to large overpotential) as a function of t.  

The time-dependent current response obtained on the first step (see Fig. 2.29) was analysed via the use of the following equation, as proposed by Shoup and Szabo [12], which sufficiently describes the current response over the entire time domain, with a maximum error of less than 0.6 %  

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Chronoamperometry was used to determine the electron-transfer kinetics and it could provide information regarding the dynamic model of an electrochanical process. In chronoamperometry, the current is integrated over relatively long time intervals thus, it gives a better signal to noise ratio in comparison to other voltammetric techniques. The Faradaic current, which is due to electron-transfer events and is... 

This is a dynamic electrochemical technique, which can be used to study electron transfer reactions with solid electrodes. A voltammo-gram is the electrical current response that is due to applied excitation potential. Chapter 18b describes the origin of the current in steady-state voltammetry, chronoamperometry, cyclic voltammetry, and square wave voltammetry and other pulse voltammetric techniques. 

The homogeneous catalysis method is suitable to measure rate constants over a very wide range, up to the diffusion limit. The lower limit is determined by interferences, such as convection, which occur at very slow scan rates. It is our experience that, unless special precautions are taken, scan rates below lOOmV/s result in significant deviations from a purely diffusion-controlled voltammetric wave. For small values of rate constants (down to 10 s ), other potentiostatic techniques are best suited, such as chronoamperometry at a rotating disk electrode UV dip probe and stopped-flow UV-vis techniques. ... 

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