Synthesis and diameter control of multi-walled carbon nanotubes over gold nanoparticle catalysts

The synthesis of multi-walled carbon nanotubes (MWNTs) was performed by the chemical vapor deposition of carbon source (C2H2, C2H4, methanol, or benzene) using dodecanethiol-stabilized gold nanoparticles (Au-DTs) with monodispersity in size from 3 to 10 nm supported on SiO2–Al2O3 as a catalyst. The influences of reaction temperature, size of Au-DT, and carbon sources on the formed MWNTs were investigated. The diameter of MWNTs could be rationally controlled by changing the size of Au-DT only when C2H2 was used as a carbon source.