The electrode reaction rate constants are related to the partial currents by
where
and
are the rate constants for the oxidizing (anodic) and reducing (cathodic) reactions
respectively,
is the charge number of the cell reaction,
is the Faraday constant
and
is the geometric area of the electrode,
the product
includes all the species
which take part in the partial reaction,
is the volume concentration of species
and
is the order of the reaction with respect to species
.
The conditional rate constant of an electrode reaction is the value of the electrode reactionrate constant at the conditional (formal) potential of the electrode reaction. When
the transfer coefficient is independent of potential,
where
and
are the anodic and cathodic transfer coefficients respectively,
is the electric potential difference,
is the conditional (formal) potential,
is the stoichiometric number,
is the gas constant
and
is the thermodynamic temperature.
Similar rate constants can be defined using activities in place of concen
trations in the first two equations, and the standard electrode potential in place of the conditional potential in the latter two equations. This type of rate constant is called the standard rate constant of the electrode reaction. The observable electrode rate constant is the constant of proportionality expressing the dependence of the rate of the electrode reaction on the interfacial concentration of the chemical species involved in the reaction.

Source:

PAC, 1974, *37*, 499*
(Electrochemical nomenclature)
* on page 515

PAC, 1980, *52*, 233*
(Electrode reaction orders, transfer coefficients and rate constants. Amplification
of definitions and recommendations for publication of parameters)
* on page 236