Large-scale purification of single-wall carbon nanotubes prepared by electric arc discharge

摘要

High-yield single-wall carbon nanotubes (SWNTs) have been mass-produced by dc arc discharge evaporation of a carbon electrode including 1 at. percebt Fe catalyst in hydrogen mixed gas [i.e., H_2-inert gas (Ne, Ar, Kr, Xe), or H_2-N_2]. The as-grown SWNTs have high-crystallinity due to the high temperature of arc plasma, and the coexisting Fe catalyst nanoparticles are embedded in very thin amorphous carbon because of the in situ etching effects of hydrogen. A macroscale purification technique, which is a whole liquid-phase purification process, first reflux treatment in H_2O_2 solution and then rinsing with hydrochloric acid, has been developed to eliminate the coexisting Fe catalyst nanoparticles and obtain SWNTs with purity higher than 90 at. percent.