title: Purification of laser synthesized SWCNTs by different methods: a comparative study.
abstract: A comparison of different purification procedures for single walled carbon nanotubes (SWCNTs) synthesized by laser-vapourization has been presented. The methods involved gas-phase oxidation by calcination, liquid-phase oxidation by H2O2, hydrothermal treatment and acid refluxing in HCI. Sample purity is documented with Raman spectroscopy, Transmission electron microscopy, Scanning electron microscopy and thermogravimetric analysis. Multi-spot analyses were done to check the homogeneity of the purified samples. Different purification processes produced SWCNT material with purity in the range of 48-78%. Raman and TEM results suggested that prolonged calcination results in selective etching of larger diameter nanotubes. SEM and TGA analyses showed increase in density of SWCNTs with better oxidation resistance after purification.
authors.affiliation: National Centre for Nano-Structured Materials, Council for Scientific and Industrial Research, Pretoria-001, Republic of South Africa.
authors.forename: Letlhogonolo
authors.initials: L
authors.lastname: Matlhoko
authors.forename: Sreejarani K
authors.initials: SK
authors.lastname: Pillai
authors.forename: Suprakas Sinha
authors.initials: SS
authors.lastname: Ray
authors.forename: Willem G
authors.initials: WG
authors.lastname: Augustyn
authors.forename: Mathew
authors.initials: M
authors.lastname: Moodley
mesh_terms: D003460:Crystallization / Q000379:methods*; D007834:Lasers; D046911:Macromolecular Substances / Q000737:chemistry / Q000528:radiation effects; D008422:Materials Testing; D008968:Molecular Conformation / Q000528:radiation effects; D036103:Nanotechnology / Q000379:methods*; D037742:Nanotubes, Carbon / Q000737:chemistry* / Q000528:radiation effects / Q000648:ultrastructure*; D010084:Oxidation-Reduction / Q000528:radiation effects; D010316:Particle Size; D013499:Surface Properties / Q000528:radiation effects
chemical_list: D046911:Macromolecular Substances; D037742:Nanotubes, Carbon