Controllable purification, cutting and unzipping of multi-walled carbon nanotubes with a microwave method

摘要

A rapid microwave-assisted method was developed for the purification, cutting and unzipping of arrays of multi-walled carbon nanotubes (MWCNTs) using a mixture of KMnO_4 and H_2SO_4. To harness the extent of treatment, MWCNT products were fully characterized at different reaction times by UV-visible and Raman spectroscopies as well as scanning and transmission electron microscopies. The results show that the carbon nanoparticles and the amorphous carbon which coated the MWCNTs were removed after about 10 minutes. The excessive oxidation of MWCNTs then leads to cutting and unzipping of graphitic walls. Moreover, while the catalyst residues outside the MWCNTs were rapidly extracted up to 10 minutes, the removal of catalyst residues inside the MWCNTs did not begin before 20 minutes. This method can be considered as an efficient route for the purification, cutting and unzipping of MWCNTs due to its fast and controllable procedure.