US Patent 8124044 - Arc discharge synthesis of CNTs

http://www.freepatentsonline.com/8124044.html

This patent from Sony teaches techniques to improve the purity and diameter uniformity of carbon nanotubes formed via an arc discharge process. Claim 1 reads:

1. A method for preparing carbon nanotubes comprising synthesizing carbon nanotubes from a carbon source using an arc-discharge process in presence of a catalyst and a promoter, wherein the promoter contains an element simple substance capable of reducing a surface energy of carbon nanotubes growth sites in the catalyst, and wherein the promoter is selected from the group consisting of Se, Te, Ge and combinations thereof.