Raman spectra and X-ray diffraction patterns of carbon nanotubes prepared by hydrogen arc discharge

This is a preliminary study on the X-ray diffraction patterns and Raman spectra of multiwalled carbon nanotubes (MWNTs) prepared using hydrogen arc discharge. For comparison, other carbon allotropes prepared using hydrogen are discharge, i.e., graphene sheets, outer shell of the cathode deposit and raw graphite rod, were also examined. The X-ray diffraction patterns of purified MWNTs were similar to those of graphene sheets, and those of the outer shell and the raw graphite rod bore a resemblance to each other. Characteristic features for each carbon allotrope were observed in the Raman spectra over a wide frequency range of 12 - 4800 cm(-1). Especially, in the Raman spectrum of purified MWNTs, the Raman-allowed phonon mode E-2g was found to be downshifted by more than 10 cm(-1) compared with that in the spectrum of the raw graphite rod.