Comparative X-ray absorption investigation of fluorinated single-walled carbon nanotubes

The C 1s and F 1s X-ray absorption spectra of pristine and fluorinated single-walled carbon nanotubes with different fluorine contents and nanodiamond as a reference compound have been measured with the aim of characterizing single-walled carbon nanotubes and their products formed upon treatment of the nanotubes with molecular fluorine at a temperature of 190°C. The spectra obtained have been analyzed by thoroughly comparing with the previously measured spectra of highly oriented pyrolytic graphite and fluorinated multiwalled carbon nanotubes and the spectrum of nanodiamond. It has been established that the fluorination of single-walled and multiwalled carbon nanotubes leads to similar results and is characterized by the attachment of fluorine atoms to carbon atoms on the lateral surface of the nanotube with the formation of the σ(C-F) bonds due to the covalent mixing of F 2p and C 2p _z π valence electron states.