User:Wibegust/sandbox

= Koutecký-Levich Equation = The Koutecký-Levich equation models the measured current due to an electrochemical reaction when mass transport and reaction rate limitations are taken into account.

The Koutecký-Levich equation is written on a general form as

$$i_m^{-1}=i_{k}^{-1}+i_{MT}^{-1} $$

where Clearly, the smallest of either ik or iMT dictates im.
 * im is the measured current (A)
 * ik is the kinetic current(A) described by Butler-Volmer equation and is a function of electrode potential E.
 * iMT is the mass transport limited current (A).

Rotating Disk Electrode Setup
In the case when Rotating disk electrode(RDE) setup is used, iMT can be modeled by the Levich equation. After a substitution, the Koutecký-Levich equation can be written as

$$\frac{1}{i_m} =\frac{1}{i_k}+\frac{1}{B_L \omega^{0.5}} $$

where With the aim of extracting the $$i_{k} $$ after an experiment where $$i_{m} $$ was measured as a function of ω, the data can be plotted in a Koutechý-Levich plot,i.e., $$i_{m}^{-1} $$ versus $$\omega^{-0.5} $$. Typically, the data will form a line. Extrapolating this line to the 0, i.e. infinite rotation, the value of $$i_{k}^{-1} $$is obtained.
 * $$B_{L} $$is the Levich Constant.
 * ω is the angular rotation rate of the electrode.

Modified Electrode
In the case the RDE is modified by a thin film, the Koutechý-Levich equation can be written as

$$\frac{1}{i_m} =\frac{1}{i_k}+\frac{1}{i_{S}}+\frac{1}{B_L \omega^{0.5}} $$

where
 * $$i_{S} $$ is the maximum current through the film.

= References =