Rotating disc electrodes: the theory of chronoamperometry and its use in mechanistic investigations

Abstract

A general computational strategy is presented for the calculation of the chronoamperometric responses arising from potential-step experiments at rotating disc electrodes. The method is applicable to a wide range of electrode reaction mechanisms and theoretical results are given for single- and double-potential-step experiments for ECE, DISP1, DISP2, EC' and CE reactions. For the last, the treatment is extended to cover the case where reactants have grossly unequal diffusion coefficients. Steadystate behaviour is also deduced. The extent to which the various mechanistic pathways can be distinguished is identified and the necessary experiments defined.

Differential Pulse and Chronoamperometric Studies of Insonated Systems: Acoustic Streaming and Cavitational Effects

“…In the case of an experiment using a rotating disk electrode, a convective term is added to the equations describing the mass transport behavior of RED and OX where Cy 2 is the convection term normal to and close to the electrode.…”

“…The diffusion layer thickness that is created by the motion of the RDE is predicted by the following equation: A coordinate transform, based on the Hale transformation, ,, was also used to improve the efficiency of the simulation. The same boundary conditions apply as for the nonconvective simulation, and the mass transport equations are solved in a similar fashion.…”

The interpretation of small molecule diffusion coefficients: Quantitative use of diffusion-ordered NMR spectroscopy

“…Diffusion coefficients are used in electrochemical techniques to describe mass transport phenomena close to the electrode surface [77]. If an electrochemical process is wellunderstood and the number of electrons being transferred is known, then electrochemical methods such as chronoamperometry [78], chronopotentiometry [79] and rotating disc electrode voltammetry [80] can be used to estimate the diffusion coefficients of the species involved. Taking chronoamperometry as an example, an electrochemical experiment where changes in electric current are measured as a function of time in response to a step change in the potential applied across the electrochemical cell, the measured current depends on the rate at which the molecule being studied diffuses to the electrode surface, giving rise to a D ½ dependence in the current [81].…”

Theoretical Analysis of Voltammetry at a Rotating Disk Electrode in the Absence of Supporting Electrolyte

“…The rotating disc electrode (RDE) is one of the convective electrode systems for which hydrodynamic equations and the convection-diffusion equation have been solved rigorously for the steady-state . RDEs have found considerable application in the study of those electrode reactions involving electron transfers coupled to homogeneous chemical reactions . For example, in the case of steady-state conditions, Levich obtained a well-known expression for the RDE limiting current at large values of the Schmidt numbers (Sc).…”