## electrode reaction rate constants

Also contains definitions of: conditional rate constant of an electrode reaction, standard rate constant of an electrode reaction
https://doi.org/10.1351/goldbook.E01961
The @[email protected] rate constants are related to the partial currents by $k_{\mathrm{ox}}=\frac{l_{\text{a}}}{n\ F\ A\ \Pi\: c_{i}^{\nu _{i}}}$ $k_{\mathrm{red}}=\frac{l_{\text{c}}}{n\ F\ A\ \Pi\:c_{i}^{\nu _{i}}}$ where $$k_{\mathrm{ox}}$$ and $$k_{\mathrm{red}}$$ are the rate constants for the oxidizing (anodic) and reducing (cathodic) reactions respectively, $$n$$ is the @[email protected] of the cell reaction, $$F$$ is the @[email protected] and $$A$$ is the geometric area of the electrode, the product $$\Pi\:c_{i}^{\nu _{i}}$$ includes all the species $$i$$ which take part in the partial reaction, $$c_{i}$$ is the volume concentration of species $$i$$ and $$\nu _{i}$$ is the order of the reaction with respect to species $$i$$. The conditional rate constant of an electrode reaction is the value of the @[email protected] @[email protected] at the @[email protected] of the @[email protected] When $$\alpha$$ the transfer @[email protected] is independent of potential, $k_{\text{c}} = \frac{k_{\text{ox}}}{\text{e}^{\frac{\alpha _{\text{a}}\ (E- E_{\text{c}}^{0'})\ n\ F}{\nu \ R\ T}}} = \frac{k_{\text{red}}}{\text{e}^{\frac{-\alpha _{\text{c}}\ (E- E_{\text{c}}^{0'})\ n\ F}{\nu \ R\ T}}}$ where $$\alpha _{\text{a}}$$ and $$\alpha _{\text{c}}$$ are the anodic and cathodic transfer coefficients respectively, $$E$$ is the @[email protected] difference, $$E_{\text{c}}$$ is the @[email protected], $$\nu$$ is the @[email protected], $$R$$ is the @[email protected] and $$T$$ is the @[email protected] Similar rate constants can be defined using activities in place of concentrations in the first two equations, and the @[email protected] in place of the conditional potential in the latter two equations. This type of @[email protected] is called the standard @[email protected] of the @[email protected] The observable electrode @[email protected] is the constant of proportionality expressing the dependence of the rate of the @[email protected] on the @[email protected] of the chemical species involved in the reaction.
Sources:
PAC, 1974, 37, 499. (Electrochemical nomenclature) on page 515 [Terms] [Paper]
PAC, 1980, 52, 233. (Electrode Reaction Orders, Transfer Coefficients and Rate Constants. Amplification of Definitions and Recommendations for Publication of Parameters) on page 236 [Terms] [Paper]