Kinetics measurements on a stationary disk electrode in a uniformly rotating fluid (SDERF). II. The electron transfer reaction in the Fe(CN)4−6/Fe(CN)3−6-system

✍ Scribed by R.V. Bucur; Adriana Bartes

• Publisher: Elsevier Science
• Year: 1979
• Tongue: English
• Weight: 344 KB
• Volume: 24
• Category: Article
• ISSN: 0013-4686
• DOI: 10.1016/0013-4686(79)80021-3

✦ Synopsis

The operation of the SDERF ell in the study of the electron transfer kinetics of the Fe(CN)' e /Fe(CN)6 --system in 1 M KCI and 1 M KNO 3 -solutions at a stationary Pt-disk electrode is reported . The experimental current-overpotential curves are recorded by linear sweep voltammetry and analysed by two different methods using the theoretical relationship derived for a stationary disk electrode placed in a free rotating fluid Both methods give the same value for the experimental rate constant k' . The effects of the temperature (0° to 40°C)and of the ratio of therotorradius (r,) to the electrode radius (r,)(r"4, = 0 .50 to 0.81) have been studied . The activation energy for the redox process in I M KCI and 1 M KNO.. 3 are : E, = 3.4 ± (1 .6 kcal/mot and E, = 3 .7 ± 0 .7 kcal/mol respectively, while the k •values at 25°C are : k'

(5 .67 f 0 .41) x 10 -3 cm . s -' and k' _ (4.53 ± 0 .29) x 10-3 cm .

s-'

respectively. The difference from the standard rate constant ke -_ 0 .100 van . s -' is explained by the effect of the cell-geometry characterized by the G-factor. so that k' = Gk' . where G z 19 for our cell .

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