Copper-copper(II) sulfate electrode

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  2. Electrodes
  3. Corrosion prevention


File:CopperSulphateElectrode.png
Diagram of an electrode used in the field

The Copper-copper(II) sulfate electrode is a reference electrode of the first kind[1], based on the redox reaction with participation of the metal (copper) and its salt - copper(II) sulfate. It is used for measuring electrochemical potential and is the most commonly used reference electrode for testing cathodic protection corrosion control systems[2].

The corresponding equation can be presented as follow:

Cu2+ + 2e- → Cu0(metal)

This reaction characterized by reversible and fast electrode kinetics[3], meaning that a sufficiently high current can be passed through the electrode with the 100% efficiency of the redox reaction (dissolution of the metal or cathodic deposition of the copper-ions).

The Nernst equation below shows the dependence of the potential of the copper-copper(II) sulfate electrode on the activity or concentration copper-ions\[ E=0.337 + \frac{RT}{2F} ln a_{Cu^{2+}} \] [4]

Commercial reference electrodes consist of a plastic tube holding the copper rod and saturated solution of copper sulfate. A porous plug on one end allows contact with the copper sulfate electrolyte. The copper rod protrudes out of the tube. A voltmeter negative lead is connected to the copper rod.

The potential of a copper copper sulfate electrode is +0.314 volt with respect to the standard hydrogen electrode.

Applications

Notes

  1. ↑ Protopopoff, et al, pg 15
  2. ↑ Peabody p.3
  3. ↑ Protopopoff, et al, pg 13
  4. ↑ Protopopoff, et al, pg 15, Eq 2

References

  • E. Protopopoff and P. Marcus, Potential Measurements with Reference Electrodes, Corrosion: Fundamentals,

Testing, and Protection, Vol 13A, ASM Handbook, ASM International, 2003, p 13-16


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