A Glassy Carbon Electrode Modified by Polypyrrole and Platinum Nanoparticles to Enhance the Catalytic Oxidation of Methanol

Abstract

A nanocomposite surface coating was prepared by electropolymerization of pyrrole by cycling the electrode potential between −0.8 and 0.8 V (vs. SCE) on the surface of a glassy carbon electrode (GCE). After formation of the polypyrrole (PPy) matrix, this surface was potentiostatically coated with platinum nanoparticles at constant potential of −0.2 V (vs. SCE). The resulting electrode is referred to as GCE/PPy/Pt. The microscopic structure and morphology of the PPy film were characterized by scanning electron microscopy. The platinum nanoparticles were uniformly dispersed in the PPy matrix, as confirmed by transmission electron microscopy. The electrochemical and catalytic activities of the GCE/PPy/Pt were compared with GCE/Pt in 0.3 mol L⁻¹ HClO₄ solution. The electrooxidation of methanol on the GCE/PPy/Pt was studied by means of electrochemical techniques. The modified electrode exhibited a significant electrocatalytic activity for methanol oxidation compared to the other electrodes used in this study. The kinetics of methanol oxidation on GCE/PPy/Pt were studied.

Keywords:

• Electrocatalyst
• Kinetic study
• Methanol electrooxidation
• Platinum nanoparticle
• Polypyrrole

Acknowledgments

The authors gratefully acknowledge the support of this work by Ferdowsi University of Mashhad, Mashhad, Iran.

Notes

^a Roughness factor [real surface area (A _r)/geometric surface area (A _g)].