Errors in the use of the Koutecky–Levich plots

A frequently employed method for the diagnosis of electrochemical mechanisms is the Koutecky–Levich (KL) method. This method is based on the extrapolation of the reciprocal of the current intensity (or density) versus the reciprocal of the square root of the rotational rate of a rotating disc electrode (plot 1/j vs. ω− 1/2). From the intercept and slope of this plot, several diffusional and kinetic parameters of the mechanism can be obtained. In this article, the relative error of jk (kinetic current density term) and of k0 (standard rate constant) is estimated and discussed. Moreover, the relative error calculation is also estimated for the case when none of the kinetic terms in the KL expression (forward and backward reactions) can be disregarded.

► Koutecky–Levich limitations evaluated.
► Relative error of jk and k0 calculated.
► Optimal potential window for jk and k0 calculation.
► KL analysis when none of the kinetic terms can be disregarded.