Preparation of polyaniline–polypyrrole binary composite nanotube using halloysite as hard-template and its characterization

Abstract

A facile approach toward self-assembly polyaniline–polypyrrole binary composite nanotubes (PAn–PPy-NTs) using halloysite as hard-template was adopted, and another innovation lied in the removal of halloysite as well as the secondary doping for the halloysite–polyaniline–polypyrrole composites (halloysite–PAn–PPy) in this study. The prepared composites were characterized with transmission electron microscope (TEM), FT-IR, X-ray diffraction (XRD), N2 adsorption–desorption isotherms and pore distribution (Brunauer–Emmett–Teller technique, BET), and thermogravimetric analysis (TGA) techniques. The eventual products had proved to be PAn–PPy-NTs after the template was removed from halloysite–PAn–PPy, and the formation process and growth mechanism of PAn–PPy-NTs were clarified and demonstrated, respectively. Cyclic voltammetry (CV) and electrochemical impedance spectrum (EIS) were used for the comparision between halloysite–PAn–PPy and PAn–PPy-NTs. The results showed that the dual-doped PAn–PPy-NTs had better electrical property and were more promising for application in electrode materials, and the mechanism of secondary doping was also researched by X-ray photoelectron spectroscopy (XPS).