Electrosynthesis of polypyrrole composite film and electrocatalytic oxidation of ethanol

Nickel oxide (NiOx) and polypyrrole (PPy) were electrodeposited from NiSO4 and pyrrole through cyclic voltammetry scans to afford PPy–NiOx composite film at controlled pH environment. Surface morphology of the composite was studied by surface microscopy techniques (SEM). The presence of Nickel in the composite films was confirmed by XRD analysis. Modified graphite electrodes (G/NiPPy) were examined for their redox process and electrocatalytic activities towards the oxidation of ethanol in alkaline solutions. The methods of cyclic voltammetry (CV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS) were employed. In CV studies, in the presence of ethanol G/NiPPy modified electrode shows a significantly higher response for ethanol oxidation. A mechanism based on the electro-chemical generation of Ni (III) active sites and their subsequent consumptions by ethanol have been discussed and the corresponding rate law under the control of charge transfer has been developed and kinetic parameters have been derived. In addition, G/NiPPy electrode shows a considerably lower onset potential than that of G/Ni in ethanol electrooxidation.