Synthesis of carbon nanotubes using polycyclic aromatic hydrocarbons as carbon sources in an arc discharge

Abstract

The influence of starting carbon materials on the synthesis of carbon nanotubes (CNTs) is investigated. Comparisons are made between graphite rods and polycyclic aromatic hydrocarbons (PAHs) as carbon sources in helium arc discharge. The major parameters are also evaluated in order to obtain high-yield and high-quality carbon nanotubes. The cathode deposits are examined using scanning electron microscopy (SEM) to determine the microstructure of carbon nanotubes. The SEM investigation of the carbon nanotube deposits formed on the cathode provides evidence that PAHs can serve as building blocks for nanotube formation. The high-temperature graphitization process induced by the arc plasma enables the hydrocarbons to act as carbon sources and changes the aromatic species into the layered graphite structure of CNT. These polycyclic aromatic hydrocarbons not only act as the precursors but also enhance the production rate of carbon nanotubes. The PAH precursors thus play an important role in the mass production of carbon nanotubes.