The thallium(I)/(III) couple at rotating disk electrodes of gold and platinum

✍ Scribed by J. Ulstrup

• Publisher: Elsevier Science
• Year: 1968
• Tongue: English
• Weight: 652 KB
• Volume: 13
• Category: Article
• ISSN: 0013-4686
• DOI: 10.1016/0013-4686(68)87024-0

✦ Synopsis

The reduction of Tl*+ ions and the oxidation of Tl+ ions at rotating disk electrodes of gold and platinum in perchloric acid have been investigated using a potentiostatic device, and the results are compared with those of earlier workers.

The current/potential curves are found to be considerably more complicated than claimed hitherto, but a potential programme has been found for the reduction process which avoids the difficulties arising from passivation of the electrodes. Using the current/potential curves and the steady-state principle it is proved that the first two, relatively slow, steps in the electrochemical reduction of T13+ are the diffusion of TP+ ions to the electrode surface and the transfer of one electron with the formation of TP+. At high positive potentials the steady-state kinetic treatment furthermore indicates that TIZ+ is reduced to Tl+, instead of the disproportionation suggested by earlier workers. The rate constants of the various steps are calculated and it is seen that the reduction takes place more rapidly on platinum than on gold.