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The Levich equation is written as: = where I L is the Levich current (A), n is the number of moles of electrons transferred in the half reaction (number), F is the Faraday constant (C/mol), A is the electrode area (cm 2), D is the diffusion coefficient (see Fick's law of diffusion) (cm 2 /s), ω is the angular rotation rate of the electrode (rad/s), ν is the kinematic viscosity (cm 2 /s), C ...
The Koutecký–Levich equation models the measured electric current at an electrode from an electrochemical reaction in relation to the kinetic activity and the mass transport of reactants. A visualization of the Koutecký–Levich equation. The graph shows the measured current as a function of the mass transport current for given kinetic current.
An RDE cannot be used to observe the behavior of the electrode reaction products, since they are continually swept away from the electrode. However, the rotating ring-disk electrode is well suited to investigate this further reactivity. The peak current in a cyclic voltammogram for an RDE is a plateau like region, governed by the Levich ...
The RRDE setup allows for many additional experiments well beyond the capacity of a RDE. For example, while one electrode conducts linear sweep voltammetry the other can be kept at a constant potential or also swept in a controlled manner. Step experiments with each electrode acting independently can be conducted.
The Tafel equation was first deduced experimentally and was later shown to have a theoretical justification. The equation is named after Swiss chemist Julius Tafel . It describes how the electrical current through an electrode depends on the voltage difference between the electrode and the bulk electrolyte for a simple, unimolecular redox reaction.
A Levich constant (B) is often used in order to simplify the Levich equation. [1] Furthermore, B is readily extracted from rotating disk electrode experimental data. The B can be defined as: [ 2 ]
In theoretical chemistry, Marcus theory is a theory originally developed by Rudolph A. Marcus, starting in 1956, to explain the rates of electron transfer reactions – the rate at which an electron can move or jump from one chemical species (called the electron donor) to another (called the electron acceptor). [1]
Linear potential sweep. In analytical chemistry, linear sweep voltammetry is a method of voltammetry where the current at a working electrode is measured while the potential between the working electrode and a reference electrode is swept linearly in time.