Electrocatalytic activity of electrodeposited composite films of polypyrrole and CoFe2O4 nanoparticles towards oxygen reduction reaction

Electrochemical behaviour of sandwich-type composite electrodes of polypyrrole (PPy) and CoFe₂O₄ nanoparticles (Ox) were investigated in an aqueous solution of 0.5 M K₂SO₄ and 5mM KOH at 25 °C using electrochemical impedance (EI), cyclic voltammetry (CV) and Tafel polarization techniques. EI and CV studies indicated that the incorporation of oxide nanoparticles influenced the charge transfer and transport behaviours of the polymer matrix greatly. The bulk electrical resistances of pure polymer (4.5 ± 1.7 Ω) as well as composite (2.7 ± 0.8 Ω) electrodes were practically constant in the potential region, +0.1 to −0.7 V. The latter electrode showed a good electrocatalytic activity towards the oxygen reduction reaction (ORR).