Electrochemical characterization of composite films of LaNiO3 and polypyrrole for electrocatalysis of O2 reduction

Electronically conductive composite electrodes G/PPy/PPy(Ox)/PPy made of polypyrrole, PPy, and the perovskite oxide LaNiO3 on graphite, G, have been obtained following a sequential electrodeposition method and were investigated by electrochemical impedance spectroscopy, linear and cyclic voltammetries in an aqueous solution containing 0.5 M K(2)SO(4)plus 5 mM KOH at 25 degrees C. Results showed that the electrical conductivity of the composite electrode remained practically constant under the cathodic polarization condition. The electrocatalytic activity of LaNiO3 towards the oxygen reduction reaction (ORR) enhanced greatly when it was used in the form of the composite electrode. The incorporation of oxide particles has been observed to influence the morphology of the polymer film.