Electrode potential, E, in electrochemistry, according to an IUPAC definition^[1], is the electromotive force of a cell built of two electrodes:

• on the left-hand side is the standard hydrogen electrode, and
• on the right-hand side is the electrode the potential of which is being defined.

By convention:

E_Cell := E_Right - E_Left

From the above, for the cell with the standard hydrogen electrode (potential of 0 by convention), one obtains:

E_Cell = E_Right - 0 = E_Electrode

Electrode potential is measured in volt (V).

[edit] Measurement

Three-electrode setup for measurement of electrode potential

The measurement is generally conducted using a three-electrode setup (see the drawing):

1. Working electrode
2. Counter electrode
3. Reference electrode (standard hydrogen electrode or an equivalent)

The potential measurements are performed with the positive terminal of the electrometer connected to working electrode and the negative terminal to the reference electrode.

The measured potential of the working electrode may be either that at equilibrium on the working electrode ("reversible potential"), or a potential with a non-zero net reaction on the working electrode but zero net current ("corrosion potential", "mixed potential"), or a potential with a non-zero net current on the working electrode.

[edit] See also

• Standard electrode potential
• Absolute electrode potential

[edit] References

1. ^ Definition of electrode potential in the IUPAC Gold Book