Direct fluorination of carbon nanocones and nanodiscs.

This work focuses on the reactivity of carbon nanodiscs and nanocones with respect to pure fluorine gas. The starting materials, as-synthesized without post-treatment, consist of a mixture of nanodiscs (approximately 70% w/w), nanocones (approximately 20% w/w) and amorphous carbons (approximately 10% w/w). In order to investigate their reactivity in pure F2 gas, two experiment sets have been performed: (i) in situ Thermo Gravimetric Analysis under diluted F2 and relative F2 pressure measurements, which highlight the temperature domain for an efficient fluorination, and then, allow the fluorination conditions to be optimized; (ii) the fluorination under pure F2 gas was performed at temperatures ranged between room temperature and 450 degrees C. Ex situ characterization was carried out using 13C and 19F solid state Nuclear Magnetic Resonance and Scanning Electron Microscopy. For the low reaction temperature (up to 300 degrees C), the chemical stability of these kinds of nanocarbons prevents from intensive fluorination. On the other hand, at temperature higher than 300 degrees C, the fluorination is important but competes with the material decomposition. The fluorination mechanism has been established taking into account NMR and SEM data.