Polypyrrole/silver composite nanotubes for gas sensors

A simple strategy for synthesizing well-defined polypyrrole (PPy) nanotube, which can be used for loading silver nanoparticles without prior PPy nanotube functionalization under mild conditions is demonstrated. It is found that Ag nanoparticles could uniformly decorate onto the PPy nanotube surface in the presence of polyvinylpyrrolidone (PVP) to form PPy/Ag composite nanotubes. Transmission electron microscopy (TEM) images give evidence of the decoration of Ag nanoparticles on the surface of PPy nanotubes. Fourier transform infrared (FTIR) spectra reveal the structure of PPy/Ag composite nanotubes and X-ray diffraction (XRD) directly shows the presence of Ag nanoparticles. The as-prepared PPy/Ag composite nanotubes are applied to the detection of ammonia vapor. Compared with PPy nanotubes, the introduction of metal onto PPy nanotubes is effective in promoting the chemiresistor response to ammonia. Moreover, the response behaviors of PPy/Ag composite nanotubes depend on the distribution of Ag nanoparticles in the nanocomposites.