ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY OF COBALT(II)-HEXACYANOFERRATE FILM MODIFIED ELECTRODES

ac impedance studies on cobalt(II)-hexacyanoferrate (CoHCF) film modified electrodes have been carried out in different aqueous solutions. The experimental impedance data were fitted to an equivalent electrical circuit giving values of the different electrochemical parameters associated with mass transport, charge transfer and double layer. Charge transfer resistances measured at the standard potential of the system are rather low and in agreement with the highly reversible behaviour of this modified electrode as found in cyclic voltammetry. The value of the capacitance associated with the film was found to vary with the concentration of the electrolyte.