Multi-walled carbon nanotube/silver nanoparticles used for thermal transportation

A green method was applied to prepare composites of multi-walled carbon nanotubes (MWNTs) decorated with silver nanoparticles (Ag-NPs). MWNTs were functionalized using ball milling technology in the presence of ammonium bicarbonate, and the traditional method of silver mirror was used to decorate MWNTs to obtain Ag/MWNT composite. The obtained Ag/MWNT composites were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transmission infrared spectroscopy, and Brunauer–Emmet–Teller (BET) surface area analysis. SEM characterization showed that Ag-NPs distributed uniformly on the walls of MWNTs. The content and size of Ag-NPs could be controlled by adjusting the redox time. XRD patterns demonstrated that the Ag-NPs are composed of pure Ag and crystallized well. BET analysis indicated that the specific surface areas of Ag/MWNT decrease with increasing the content of Ag-NPs, and this result is similar to that of the literature. The measurement results of the thermal property showed that the thermal conductivity of the nanofluid containing Ag/MWNT composites was higher than that of nanofluid containing pristine or functionalized MWNTs.