The Auxiliary electrode, often also called the counter electrode, is an electrode used in a three electrode electrochemical cell for voltammetric analysis or other reactions in which an electrical current is expected to flow.[1][2][3] The auxiliary electrode is distinct from the reference electrode, which establishes the electrical potential against which other potentials may be measured, and the working electrode, at which the cell reaction takes place.
The auxiliary electrode's potential is opposite in sign to that of the working electrode, but its current and potential are not measured. Rather, it is used to ensure that current does not run through the reference electrode (three electrode system), which would disturb the reference electrode's potential. The auxiliary electrode often has a surface area much larger than that of the working electrode to ensure that the reactions occurring on the working electrode are not surface area limited by the auxiliary electrode.
When using a three electrode cell to perform electroanalytical chemistry, the auxiliary electrode is often isolated from the working electrode using a glass frit. Such isolation prevents any byproducts generated at the auxiliary electrode from contaminating the main test solution and interfering with the analytical measurement being made at the working electrode.
Auxiliary electrodes are often fabricated from electrochemically inert materials such as gold, platinum, or carbon.
See also
References
- ^ Kissinger, Peter; William R. Heineman (1996-01-23). Laboratory Techniques in Electroanalytical Chemistry, Second Edition, Revised and Expanded (2 ed.). CRC. ISBN 0824794451.
- ^ Bard, Allen J.; Larry R. Faulkner (2000-12-18). Electrochemical Methods: Fundamentals and Applications (2 ed.). Wiley. ISBN 0471043729.
- ^ Zoski, Cynthia G. (2007-02-07). Handbook of Electrochemistry. Elsevier Science. ISBN 0444519580.
Further reading
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