# Impedance of a Redox Reaction (E) at a Rotating Disk Electrode (RDE)

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This Demonstration shows the change in the Nyquist plane of Faradaic () and electrode () impedance for the redox electrochemical reaction () at a rotating disk electrode (RDE).

Contributed by: Jean-Paul Diard and Claude Montella (September 2010)
Open content licensed under CC BY-NC-SA

## Details

The current density versus potential ( versus ) curve for a redox reaction () under steady-state conditions at a rotating disk electrode (RDE) is

, , , , , .

Faradaic () and electrode (Z) impedance for the redox electrochemical reaction (E) at a RDE, taking into account the series ohmic resistance , are given by

, , ,

, , ,

, ,

, ,

where is the angular frequency, is the charge transfer resistance, is the mass transport resistance, is the interfacial double capacitance, is the time constant of the mass transport, is the characteristic frequency of the charge transfer, and is the characteristic frequency of the mass transport.

References

[1] J.-P. Diard, C. Montella, and B. Le Gorrec, Cinétique Electrochimique, Paris: Hermann, 1996.

[2] C. Montella, J.-P. Diard, and B. Le Gorrec, Exercices de Cinétique Electochimique, II Méthodes d'impédance, Paris: Hermann, 2005.

[3] M. E. Orazem and B. Tribollet, Electrochemical Impedance Spectroscopy, Hoboken: John Wiley & Sons, 2008.