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 (redox) reactions that occur at the surface of an electrode, as well as an investigation into electrochemical reaction mechanisms. Two accompanying processes are involved in the electrochemical reaction and influence the overall reaction rate:
Contributors to this field include Alexander Frumkin, John Alfred Valentine Butler, Max Volmer, and Julius Tafel.
An elementary charge transfer step can be described by the Butler–Volmer model proposed by John Alfred Valentine Butler and Max Volmer. The reaction rate is given by the Butler-Volmer equation:[1]
j=j0\left\{\exp\left[
| (1-\alpha)zF | |
| RT |
η\right]-\exp\left[-{
| \alphazF | |
| RT |
}η\right]\right\}, η=
| E-Eeq |
In this equation
j
j0
\alpha
z
F
R
T
η
Eeq
E
The equation yields a negative current density for a reduction reaction (negative overpotential) and a positive current density for an oxidation reaction (positive overpotential). The sign of the current density has no physical meaning and is defined by an international convention.