Abstract
A two-step method for the purification of single-walled carbon nanotube (SWCNT) rope containing substantial catalyst particles embedded in carbonaceous shells was developed. The first step was the triggering of rope ignition using a 9-V battery, which resulted in pre-oxidization of the carbon shells on the Fe 3 C catalyst and oxidation of the exposed Fe 3 C to form Fe 2 O 3 . In addition, SWCNTs with open-end structures due to ignition-induced cutting remained. In the second step, both oxalic acid (H 2 C 2 O 4 ) and hydrochloric acid (HCl) were used as the reactants to remove the Fe 2 O 3 particles. No damage on the SWCNT walls after H 2 C 2 O 4 or HCl purification was found. In addition, adsorption of H 2 C 2 O 4 was also found on the H 2 C 2 O 4 purified SWCNT rope and it can be effectively removed by heating the rope at 200 °C in vacuum for 40 min. Samples were characterized by SEM, TEM, Raman spectroscopy, TGA, FTIR, XPS, and UV-Vis-NIR. © 2010 Elsevier Ltd. All rights reserved.