Facile synthesis of Ag nanoparticles supported on MWCNTs with favorable stability and their bactericidal properties

Stable Ag nanoparticles supported on multi-walled carbon nanotubes (MWCNTs) have been successfully synthesized by calcinations of the complexes of Ag cation and acid-treated MWCNTs under sparging N2. The nanocomposites are characterized in detail by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV-visible absorption spectroscopy. The results indicate that Ag nanoparticles are relatively homogeneously dispersed on the surface of MWCNTs. The bactericidal properties of Ag/MWCNT nanocomposites are investigated with disk diffusion assay on the suspension samples inoculated with Escherichia coli. The results show that Ag/MWCNTs-500 nanocomposites possess excellent bactericidal property because of their suitable particle size (15 nm). Moreover, Ag nanoparticles supported on MWCNTs are very stable for half a year. What is more, the bactericidal effect was enhanced obviously under solar irradiation. This is because MWCNTs can absorb near-infrared light to kill parts of bacteria. A possible formation mechanism is also proposed in this article.