Purification of single-walled carbon nanotubes

¹ IMN, CNRS UMR 6502, Université de Nantes, 2 rue de la Houssinière, BP 32229, 44322 Nantes, France
² Nanochemistry Research Institute, Curtin University of Technology, GPO Box U1987, Perth 6845, Western, Australia
³ Chemistry Department, Science Faculty, Hawassa University, P.O. Box 5, Addis Ababa, Ethiopia
⁴ Department of Mechanical and Manufacturing Engineering, Aalborg University, Pontoppidanstraede 105, 9220 Aalborg East, Denmark

Corresponding author: chris.ewels@cnrs-imn.fr

Received: 3 December 2010
Accepted: 7 January 2011
Published online: 13 April 2011

Abstract

We present a study of purification of single-walled carbon nanotubes (SWCNTs) using different oxidation temperatures and chemical treatments. We have developed a simple two annealing-steps procedure resulting in high nanotube purity with minimal sample loss. The process involves annealing the SWCNTs at 300 °C for 2 h with subsequent reflux in 6 M HCl at 130 °C, followed by further annealing at 350 °C for 1 h with reflux in 6 M HCl at 130 °C. The process results in effective removal of carbon impurities and metal particles which are associated with SWCNTs production. The process is less time consuming (complete in 4.5 h) than conventional acid purification methods which require over 5 h, and less destructive than conventional methods with a yield of 26%. SWCNT purity was assessed using Raman spectroscopy, thermogravimetry and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy.