Facilitating the CVD synthesis of seamless double-walled carbon nanotubes

In this contribution we present a simple laser assisted chemical vapour (LA-CVD) technique that rapidly determines if a given catalyst and feedstock combination are appropriate for the bulk synthesis of double-walled carbon nanotubes (DWCNT) in conventional thermal CVD (T-CVD). Systematic T-CVD studies across a range of temperatures with a Fe-Co catalyst mix for two carbon feedstocks (ethanol and methane) were conducted to validate the LA-CVD technique. The T-CVD findings confirm that the LA-CVD route is appropriate as a fast and easy means to determine the primary carbon nanotube product for a selected catalyst and feedstock in T-CVD. The LA-CVD route reduces the optimization parameters in T-CVD to only that of temperature. The studies led to the bulk production of seamless DWCNT with yields better than 55%.