The synthesis of highly electroactive N-doped carbon nanotube/polyaniline/ Au nanocomposites and their application to the biosensor

Novel N-doped carbon nanotube/polyaniline/Au (N-CNT/PANI/Au) composite nanotubes with an average diameter about 60 nm were synthesized. The morphology, composition, optical properties, and conductivity of the resulting composites were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), ultraviolet visible (UV-vis) absorption spectrum, X-ray photoelectron spectroscopic (XPS) and Fourier transform infrared (FTIR) spectroscopy. Cyclic voltammetric experiments indicated that this nanocomposite showed excellent redox ability not only in acidic solution but also in neutral solution. Based on the good biocompatibility, the higher conductivity and excellent redox ability, a H₂O₂ sensor was constructed and the corresponding electrochemical properties were investigated in detail. The results confirmed that N-CNT/PANI/Au possessed an excellent catalytic activity toward the redox reaction of H₂O₂ at low reduction and oxidation overpotential. The biosensor exhibited good reproducibility, stability and a super highly sensitive response to H₂O₂ with a detection limit of 1.4 μM.