Rotating disk electrode voltammetry diffusion layer thickness

Voltammetry. Diffusional effects, as embodied in equation 1, can be avoided by simply stirring the solution or rotating the electrode, eg, using the rotating disk electrode (RDE) at high rpm (3,7). The resultant concentration profiles then appear as shown in Figure 5. A time-independent Nemst diffusion layer having a thickness dictated by the laws of hydrodynamics is established. For the RDE,... 

The advantages of a solid electrode of fixed area that functions in the voltammetric experiment with a constant diffusion-layer thickness have led to the development of the rotated-disk and ring-disk electrodes.52-54 By rotation of a disk, the electrode diffusion layer becomes fixed such that the current is constant as a function of time and does not decay [in contrast to conventional voltammetry Eq. (3.6)]. Voltammetry with such an electrode system gives a current-potential wave that is analogous to a polarogram and follows the relationship... 

Table 6.4 gives the output of Program 5 under certain conditions. We see that for a layer thickness z/ = 2.5 x 10" cm, Program 5 finds a value of Hip close to that obtained by other techniques [Table 6.4(a)]. Orthogonal collocation is used to simulate rotating ring disk electrodes and cyclic voltammetry for CE and EC mechanisms. Furthermore orthogonal collocation is used to characterize diffusion at microelectrodes and microelectrode arrays. ... 

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