Patent ID: 7670583

Claim:
A method for purifying SWNTs, said method comprising the steps of: a) providing a quantity of unpurified SWNTs, wherein the unpurified SWNTs further comprise metal particles and non-nanotube carbon structures; b) simultaneously exposing the unpurified SWNTs to oxygen and a fluorine-containing gas at elevated temperatures to form metal oxide/fluoride particles and partially-purified SWNTs, wherein the exposing step oxidizes and removes at least a majority of the non-nanotube carbon structures; and wherein the exposing step oxidizes the metal particles to metal oxide particles and inactivates the metal oxide particles by at least partially converting the metal oxide particles into metal fluoride particles to form the metal oxide/fluoride particles; wherein the metal oxide/fluoride particles are non-catalytic toward SWNT oxidation; c) annealing the partially-purified SWNTs in an atmosphere comprising H 2 to yield reduced partially-purified SWNTs; and d) extracting the reduced partially-purified SWNTs with an acid to yield purified SWNTs, wherein the extracting step comprises removing the metal oxide/fluoride particles.