A composite of polypyrrole nanowire platinum modified electrode for oxygen reduction and methanol oxidation reactions

The formation of polypyrrole (PPy) nanowires containing highly dispersed Pt nanoclusters composite was synthesized on glassy carbon electrode (GCE) utilizing cyclic voltammetry (CV) method. Metallic Pt clusters were dispersed in electrically conducting PPy nanowires in order to achieve multielectron-transfer processes in a three-dimensional matrix. The electrocatalytic activities toward oxygen reduction reaction (ORR) and methanol oxidation reaction (MOR) have been investigated by CV and chronoamperometry. The PPy-Pt/GCE provided an ORR peak at about 0.52 V (vs saturated calomel electrode) at 50 mV s(-1). The CV measurements at different scan rates showed that oxygen reduction at the PPy-Pt/GCE was a diffusion-controlled process. For MOR, a high ratio of forward anodic peak current to reverse anodic peak current was observed, indicating an efficient oxidation of methanol to CO2 at the PPy-Pt/GCE. Larger surface area and higher electrocatalytic activity for ORR and MOR were found at PPy-Pt nanocomposite in comparison with pure Pt modified electrode, which was attributed to high dispersion of Pt nanoclusters in large surface area of PPy nanowires and synergic effect of the Pt core-PPy shell. The results revealed that the PPy-Pt nanocomposite was an effective electrocatalyst for direct methanol fuel cells. (c) 2007 The Electrochemical Society.