▎ 摘　　要

A composite of polypyrrole (PPy) and graphene nanoplatelets (GNs) decorated with titanium dioxide (TiO2) nanoparticles (TiO2@PPy-GN) was synthesized by a sol-gel process combined with in situ chemical polymerization. The microstructure, morphology, and crystallinity of the TiO2@PPy-GN nanocomposite were characterized by Fourier-transform infrared spectrometry, scanning electron microscopy, transmission electron microscopy, and X-ray diffraction. The results indicate that the TiO2 nanoparticles with a diameter of 10-30 nm were well dispersed on the PPy-GN composite. The TiO2@PPy-GN nanocomposite exhibited good electrical-resistance response to NH3 at room temperature. Compared to the PPy-GN thin film, the TiO2@PPy-GN thin film showed enhanced NH3-sensing properties in the form of higher sensitivity and much faster response under the same conditions. The selectivity and stability of the NH3 sensor based on the TiO2@PPy-GN nanocomposite were also investigated. (C) 2015 Elsevier Ltd and Techna Group S.r.l. All rights reserved.