Two Simultaneously Occurring Electrode Processes

Distinguishing between Two Simultaneously Occurring Electrode Processes 

Distinction by the spectral characteristics, i.e. wavelength dependence, is well known. When two processes are occurring simultaneously and if the spectrum of one of them is known, deconvolution of the experimental spectral curve enables us to distinguish them. The details of this general method are not given here, but the latter method is described using a practical example of the discrimination of two simultaneously occurring redox processes in the frequency domain. 

The phase-shifting technique is easy and useful to separate two electrode surface processes, whether faradaic or non-faradaic. Assume that has two components  

By making a counterclockwise rotation of the complex plane coordinate by an angle of j 2 (Fig. 2.26), the ac reflectance R ac on the new coordinate plane is written as 

The second term now has only a real component. This means that the imaginary part of R ac solely contains the spectral information of the process ARaci in the first term in the right hand side of Eq. (40). This method is called the phase shifting technique [87, 88]. 

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Distinguishing between Two Simultaneously Occurring Electrode Processes 85... 

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