Production of electrochemical reactions
Electrochemistry - Preliminaries to the study of electrolysis

The production of an electrochemical reaction requires the realization of conditions that make the electrode potential different from the equilibrium potential, i.e. the establishment of an electrode "overpotential" (or "overvoltage"), η = Δφ – Δφ _eq = E – E _eq ≠ 0. This difference, by creating an imbalance in the system, causes an evolution (more or less rapid) tending towards the re-establishment of a new state of equilibrium.

If we are dealing with an Ox/Red system in solution, such that before establishing the overpotential we have : $E_{\text{eq}}=E^{\text{o}}+\frac{\mathrm{2,3}RT}{\text{n}F}\text{lg}\frac{c_{\text{Ox}}^{\text{o}}}{c_{\text{Red }}^{\text{o}}}$