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 (∼70% w/w), nanocones (∼20% w/w) and amorphous carbons (∼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 °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 °C), the chemical stability of these kinds of nanocarbons prevents from intensive fluorination. On the other hand, at temperature higher than 300 °C, the fluorination is important but competes with the material decomposition. The fluorination mechanism has been established taking into account NMR and SEM data.