The formation of stacked-cup carbon nanotubes using chemical vapor deposition from ethanol over silica

Processes involved in using SiO2 particles as catalysts for stacked-cup carbon nanotube formation in a spray pyrolysis chemical deposition method from ethanol were investigated. In addition, the recyclability of the SiO2 substrates is investigated. The SiO2 particles are shown to reduce to SiC. Moreover, the addition of triethylborate to produce boron species, and extended reactions, through recycling, leads to higher yields by improving the availability of SiC species. The formation of the carbon nanostructures is best explained through a carbon dissolution mechanism.