A process for manufacturing carbon nanotubes, including a step of inducing
electrical current through a carbon anode and a carbon cathode under
conditions effective to produce the carbon nanotubes, wherein the carbon
cathode is larger than the carbon anode. Preferably, a welder is used to
induce the electrical current via an arc welding process. Preferably, an
exhaust hood is placed on the anode, and the process does not require a
closed or pressurized chamber. The process provides high-quality,
single-walled carbon nanotubes, while eliminating the need for a metal
catalyst.