What is the Purpose of Counter Electrodes in Electrochemical Reaction

What is the Purpose of Counter Electrodes in Electrochemical Reaction?

Most electrochemical methods involve the use of three electrodes; namely the working electrode (WE), reference electrode (RE), and the counter electrode (CE) which is also called the secondary or auxiliary electrode. The three electrodes are connected to a potentiostat /galvanostat, which is an instrument that can perform both controlled potential (potentiostatic) and controlled current (galvanostatic) experiments. The potential drop near the other current-carrying electrode (the counter electrode) is not important when a three-electrode potentiostat is used.

The counter electrode is used for voltammetric analysis or other reactions in which an electric current is expected to flow. It 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.

When a three electrode cell is used to perform electroanalytical chemistry, the counter electrode along with the working electrode, provides a circuit over which current is either applied or measured. Here, the potential of the counter electrode is usually not measured and is adjusted so as to balance the reaction occurring at the working electrode. This configuration allows the potential of the working electrode to be measured against a known reference electrode without compromising the stability of that reference electrode by passing current over it.

Counter electrodes can be in gold, platinum, or carbon material.