CVD Generation of Single-Walled Carbon Nanotubes from Alcohol

Abstract

The CVD generation technique of single-walled carbon nanotubes (SWNTs) from alcohol is discussed in terms of the use of metal catalysts. By using alcohols such as ethanol and methanol as the carbon sources in catalytic CVD, high-purity SWNTs without metal particles, amorphous carbon or MWNTs can be synthesized at relatively low reaction temperatures of 600−800oC. For the bulk generation of SWNTs, Fe/Co bimetal catalysts supported on USY zeolite is employed. The diameter and chirality distributions, which are examined by resonant Raman scatterings and near infrared fluorescence spectroscopy, can be quite narrow at lower CVD temperatures. Combined with the molecular dynamics simulation of the nanotube growth process, the determination mechanism of chirality by the nanotube cap structure is demonstrated. In addition to the bulk generation by using zeolite, Fe/Co or Co/Mo nano-particles directly located on quartz or silicon substrate by dip-coating can be used as efficient catalysts. With this latter system, detailed characterization of catalysts and the growth of vertically aligned SWNTs mat on a quartz substrate are demonstrated.