Thermal activation of electrochemical processes in a Rf-heated channel flow cell: experiment and finite element simulation

Citation
Fl. Qiu et al., Thermal activation of electrochemical processes in a Rf-heated channel flow cell: experiment and finite element simulation, J ELEC CHEM, 492(2), 2000, pp. 150-155
Citations number
24
Categorie Soggetti
Spectroscopy /Instrumentation/Analytical Sciences
Journal title
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
ISSN journal
15726657 → ACNP
Volume
492
Issue
2
Year of publication
2000
Pages
150 - 155
Database
ISI
SICI code
Abstract
A novel approach to thermoelectrochemistry is presented which involves the direct heating of the working electrode in a channel flow cell system by ed dy currents caused by 8 MHz radio frequency (Rf) radiation. For the model r edox systems Fe(CN)(6)(3-/4-) and Ru(NH3)(6)(3+/2+) it is shown that it is possible to perform electrochemical experiments with simultaneous thermal a ctivation at temperatures close to the boiling point of the electrolyte sol ution. Quantitative analysis of data obtained from thermoelectrochemical st udies in the Rf-heated channel flow system is possible with the help of a c omputer model. Numerical simulation results obtained with a finite element program (FIDAP(TM)) for the complex heat and mass flow during voltammetric experiments at the heated electrode are shown to be in quantitative agreeme nt with experimental data. Both the increase in the rate of diffusion as we ll as the change in the flow pattern in the heated low viscosity region of the channel are shown to contribute significantly to the enhanced mass tran sport. After confirming the quantitative agreement of the numerical model w ith the data obtained for the oxidation of Fe(CN)(6)(4-) and the reduction of Fe(CN)(6)(3-) in 0.1 M KCl, the activation energy for the Ru(NH3)(6)(3+/ 2+) redox system diffusion in 0.1 M KCl is determined. (C) 2000 Elsevier Sc ience B.V. All rights reserved.