Redox electrode

A redox electrode is an electrode made from electron-conductive material and characterized by high chemical stability in the solution under test. It is used for measuring the redox potential of a specific redox system in solution, and for electrochemical studies (investigation of electrochemical kinetics of interfacial processes).

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The correlation of an electrode potential and redox system composition can be described by the Nernst equation:

Ox + ne^- = Red

,

where

E⁰ - standard potential of a specific redox system,

R - gas constant,

T - temperature in kelvins,

n - number of electrons taking part in a specific redox reaction,

F - Faraday constant

a_ox, a_red - activity of oxidising and reducing participants in redox reaction.

There are two general classes of redox electrodes:

• metals (the most common are platinum and gold, but for special purposes other materials such as titanium or iridium can be used)
• semiconductors (the most common are graphite, diamond, and SnO₂)

Illustration

A gold disk redox electrode with a Teflon shroud insulating the disk.

See also

• Reference electrode
• Flow battery