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), N-2 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). (C) 2013 Elsevier B.V. All rights reserved.