Transport behaviour of Cl- in composite films of polypyrrole and CoFe2O4 obtained for oxygen reduction

摘要

Electrodeposited films of polypyrrole (PPy) and composite of PPy and CoFe2O4 nanoparticles, incorporated with a charge compensating electrolyte anion (Cl-) are obtained on polished and pretreated graphite electrodes. Electrochemical investigations of these electronically conductive films carried out in a 0.8 mol dm(-3) KCl + 5.0 mmol dm(-3) KOH solution show that incorporation of oxide nanoparticles decreases porosity of the polymer matrix. The average apparent diffusion coefficient (D-a) value of dopant (Cl-) is observed to be approximately 3 times higher in a pure PPy-film compared to composite one. The sum of the film and solution resistances, though higher with the composite electrode, remained practically constant under cathodic polarization conditions. In contrast to a non-composite electrode of the same oxide, the composite electrode exhibited much better electrocatalytic activity and remarkable stability for O-2 reduction reaction (ORR).