Decorating multi-walled carbon nanotubes with Au nanoparticles by amphiphilic ionic liquid self-assembly

Multi-walled carbon nanotubes (MWCNTs) could be well dispersed in the aqueous solution of 1-hexadecyl-3-methylimidazolium bromide ([C16mim]Br), an amphiphilic ionic liquid, because of hydrophobic interaction. [C16mim]Br could self-assemble and form hemimicelles on the surfaces of MWCNTs. MWCNTs became positively charged due to the adsorption of C16mim+ and negatively charged Au nanoparticles (Au NPs) could be easily attached to the surfaces of MWCNTs by electrostatic interaction. In the UV–vis region, disappearance of characteristic adsorption peaks of MWCNTs and Au NPs indicates that Au NPs are completely attached to the MWCNTs in aqueous solution. Transmission electron microscope (TEM) images show Au NPs are uniformly deposited on the walls of MWCNTs. Both X-ray powder diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) patterns illustrate the existence of high purity Au NPs in MWCNTs–Au NPs hybrids. In this work, amphiphilic ionic liquid has been used to disperse MWCNTs and subsequently MWCNTs–Au NPs hybrids have been prepared by a very simple strategy.