Electrochemical Preparation of Polypyrrole/Multiwalled Carbon Nanotubes Composites in HCl and HClO4 Media

Abstract

In this paper we report the electropolymerization andcharacterization of polypyrrole/carbon nanotube composites in twoacidic media, HCl and HClO4. Cyclic voltammetry (CV) andscanning electron microscopy (SEM) were used to investigate theelectrochemical and morphological properties of the films; theseproperties are compared with their respective pure polymerprepared under similar conditions. It is observed that regardless thedopant anion (Cl– or ClO4–), the composite films exhibit highercurrents than the corresponding polymeric film, which is indicativeof a larger capacitance of the composite films. This behavioragrees well with the highly porous structure of the composite ascompared with the pure polymer, which has a more compactstructure. It is demonstrated that a decrease in the scan rate usedduring the synthesis leads to composites with higher charge storagecapacity and superior electrochemical stability during chargedischargecycles.