Heterogeneous electron-transfer rate constants for fe(h(2)o)(6)(3+/2+) at metal oxide electrodes.

The title redox couple, in noncoordinating perchlorate medium, has been used to probe the electrochemical behavior of different IrO2-based electrodes; pure oxide electrodes, as well as IrO2-SnO2 mixtures, have been investigated. The obtained results show that the electrode material strongly affects the electrochemical response. A tentative explanation, based on the different point of zero charge of the considered oxides, is presented.