Attachment Of Gold Nanoparticles To Thiol-modified Multiwall Carbon Nanotubes

Carbon nanotubes (CNTs) with unique structures and special properties have received much attention in many fields for their promising applications in many areas. Owing to their excellent mechanical and electronic performance, CNTs can be used to prepare high-strength composites, conductive materials, field emission sources, nanometer semiconductor devices, etc. Gold nanoparticles exhibit particular diversity in optical and electronic properties under different environments and have received extensively study. To optimize the potential applications of CNTs it is essential to modify CNTs via some method. Carbon nanotubes/nanogold composite have prepared though attached gold nanoparticles to the carbon nanotube. On this basis, it is of interests to cany out studies on special functional material, such as sensitive material for study of sensor.Raw CVD grown multiwall carbon nanotubes (MWCNTs) were treated with hydrochloric acid to remove the residual catalysts and amorphous carbon particles, and oxidized in a mixture of concentrated sulfuric acid and nitric acid to form functional groups such as hydroxyl and carboxyl groups on their surfaces, which made the thiol-decoration on CNT possible.The functionalized MWCNTs were then thiol-modified with (3-mercaptopropyl)-trimethoxysilane (MPTMS), which enable CNT as the carrier in the process of creating composite. The EDAX spectrum confirmed that the MWCNTs were modified by MPTMS and thiol groups were successfully introduced onto the surfaces of the MWCNTs.Colloidal gold was prepared from hydrogen tetrachloroaurate by using Na3-citrate as reducing agent. The TEM and SAED proved that nanoparticles were gold nanoparticles, with size around 16-20nm.It realized the gold nanometer particle on thiol-modified carbon nanotube (MWCNT-SH) surface equipment by chemical adsorption on normal temperature, have prepared carbon nanotubes/nanogold composite. Studies have shown, the structure of samples is steady, the nanogold particles on the carbon nanotubes takes the form of ball and distributed evenly. CNT/Au composite were prepared from in-situ growth method by using Na₃-citrate as reducing agent, and MWCNT-SH as carrier. TEM images and EDX data confirmed that the MWCNT/gold nanoparticle composite was formed and that the gold nanoparticles growed along the walls of the MWCNTs, and the diameter of the gold nanoparticles is 2nm.