Rotating potential step

At a double electrode, such as the rotating ring—disc electrode, a potential step at the disc will produce a ring current transient, the form of which is affected only by Faradaic current components at the disc. This fact can be very useful in separating Faradaic and non-Faradaic processes. 

Whilst cyclic voltammetry is an informative technique, quantitative studies, particularly on the kinetics of decay of an electrogenerated intermediate, are often best made using other controlled potential techniques. In particular, potential-step and rotating ring-disc measurements give high-quality data.1... 

Step 3b Make adjustments as in 3a but include rotational barriers. Step 3c Make adjustments as in 3a but include all potentials of their full values. 

Is used to transform the complex rotated potential back to the real potential. Step (11). The inner projection technique (11) is adopted such that... 

Although a major advantage of rotating disk electrode techniques, compared to stationary electrode methods, is the ability to make measurements at steady state without the need to consider the time of electrolysis, the observation of current transients at the disk or ring following a potential step can sometimes be of use in understanding an electrochemical system. For example the adsorption of a component. 

An armoury of powerful electrochemical methods is available. Potential step techniques such as differential pulse DP or square-wave SW voltammetry offer advantages in sensitivity and resolution. Hydrodynamic techniques involving use of rotating disc or rotating ring-disc electrodes allow the chemical steps of the electrode process to be separated from mass transport. Electrochemical transformations may be monitored optically with spectroelectrochemical methods. Even the electrode interface itself is amenable to study by in situ spectroscopic techniques. Detailed descriptions of these methods are to be found in appropriate texts [1-4]. 

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