Abstract
We investigate the purification of as-prepared multi-wall carbon nanotubes (MWCNTs) by exposure to ultraviolet lamp (lambda=185 nm). UV irradiation was conducted under ambient condition in a UV lamp chamber which had a layer of reflective aluminium foil inside to ensure the entire sample would have an even exposure to UV. Raman spectroscopy before and after UV exposure indicates the removal of non-nanotube material. The narrowing of D-band is consistent with highly purified nanotube which is seen in our results. Raman result shows that the ozone oxidation can remove the defect site of nanotubes. Intensity of G- and D*- band increases rapidly with increasing the oxidation time. Intensity ratio I-D*/I-D increases continually with increasing the ozone oxidation time which confirm the reduction of impurities from the MWCNTs.