An explicit finite difference simulation for chronoamperometry at a disk microelectrode in a channel flow solution

Russell J. Tait, Peter C. Bury, Barrie C. Finnin, Barry L. Reed, Alan M. Bond

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Abstract

An explicit finite difference simulation is used to describe chronoamperometry at a disk microelectrode in a channel flow solution. All known phenomenologically important processes are represented in the simulation, including the electrode "edge effect" in all three spatial dimensions and the parabolic flow profile of a viscous liquid in a channel. The simulation was achieved with the use of an exponentially expanding spatial grid and a variable time increment to minimise the computational requirements. The simulation was used to study the effects of electrode radius, solution velocity and channel thickness on both the near steady-state limiting current (Ilimnss) and the time taken to achieve the near steady-state condition (tnss) for a reversible one-electron charge transfer process. It was found that the solution velocity had a dramatic effect on both Ilimnss and tnss, with an increase in Ilimnss and decrease in tnss being observed with increased solution velocity. The relationships between Ilimnss or tnss and solution velocity were found to be non-linear. The results of the simulation compared favourably with experimental data obtained from the limiting current region of near steady-state voltammograms for the reversible oxidation of ferrocene at platinum disk microelectrodes of radii over the range 5-50 μm.

Original languageEnglish
Pages (from-to)25-42
Number of pages18
JournalJournal of Electroanalytical Chemistry
Volume356
Issue number1-2
DOIs
Publication statusPublished - 15 Sept 1993

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