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Tafel plot for an anodic process . The Tafel equation is an equation in electrochemical kinetics relating the rate of an electrochemical reaction to the overpotential. [1] The Tafel equation was first deduced experimentally and was later shown to have a theoretical justification. The equation is named after Swiss chemist Julius Tafel.
In electrochemistry, exchange current density is a parameter used in the Tafel equation, Butler–Volmer equation and other electrochemical kinetics expressions. The Tafel equation describes the dependence of current for an electrolytic process to overpotential.
The overpotential increases with growing current density (or rate), as described by the Tafel equation. An electrochemical reaction is a combination of two half-cells and multiple elementary steps. Each step is associated with multiple forms of overpotential. The overall overpotential is the summation of many individual losses.
the low overpotential region (called "polarization resistance", i.e., when E ≈ E eq), where the Butler–Volmer equation simplifies to: = (); the high overpotential region, where the Butler–Volmer equation simplifies to the Tafel equation.
At high overpotentials, the Butler–Volmer equation simplifies to the Tafel equation. The Tafel equation relates the electrochemical currents to the overpotential exponentially, and is used to calculate the reaction rate. [11] The overpotential is calculated at each electrode separately, and related to the voltammogram data to determine ...
Julius Tafel was born in the village of Choindez in Courrendlin, Switzerland on 2 June 1862. Tafel's father, Julius Tafel Sr. (1827-1893) studied chemistry in Tubingen and became a director of Von Roll’s iron and steel works located in Choindez in 1856, and then took a top management position in steel works located in Gerlafingen in 1863.
Electrochemical kinetics is the field of electrochemistry that studies the rate of electrochemical processes. This includes the study of how process conditions, such as concentration and electric potential, influence the rate of oxidation and reduction reactions that occur at the surface of an electrode, as well as an investigation into electrochemical reaction mechanisms.
The shift in mechanism between the pH extremes has been attributed to the kinetic facility of oxidizing hydroxide ion relative to water. Using the Tafel equation, one can obtain kinetic information about the kinetics of the electrode material such as the exchange current density and the Tafel slope. [6]