Coupled homogeneous electrode reactions current step

Chronoamperometry Chronoamperometry involves the study of the variation of the current response with time under potentiostatic control. Generally the working electrode is stepped from a potential at which there is no electrode reaction to one corresponding to the mass-transport-limited current, and the resulting current-time transient is recorded. In double-step chronoamperometry, a second step inverts the electrode reaction and this method is useful in analysing cases where the product of the initial electrode reaction is consumed in solution by a coupled homogeneous chemical reaction. 

We consider three simple schemes, shown in Fig. 6.11, and examine the effect of homogeneous coupled reactions on the current at the electrode they are CE, EC, and EC, where E represents an electrochemical step (at the electrode) and C a chemical step (in solution). The equations to calculate the rate constants from experimental measurements for the various types of electrode can be found in the specialized literature. In most studies the electrochemical step has been considered reversible—thus, in the following, the rate constant for the electrode reaction is not indicated. 

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