Electrode Kinetics of Fe(III)/Fe(II) Redox Couple on an Electrodeposited Ruthenium Electrode

The heterogeneous electron transfer in Fe(CN)g /3" and aquo complexes of Fe3+/2+ redox couples have been investigated on a ruthenized platinum electrode in 0.5 mol dm-3 sulphuric acid solution. Qualitative voltammetric data measured on a rotating disc electrode showed that a ruthenized platinum layer was a good electronic conductor, which did not block electron transfer in either direction of Fe(CN)g_/3_ redox couple. Quantitative electrode kinetic data were obtained using aquo complexes of Fe3+/2+ redox couple on a freshly deposited ruthenium electrode and on an electrode activated to the state of enhanced oxygen evolution from acid solution. The heterogeneous electron transfer rate constant of 3.9 x 10~5 cm s_1 on the unactivated electrode increased by 30% in the case of the activated electrode