Nitrogen-Doping Chemical Behavior Of Graphene Materials With Assistance Of Defluorination

Heteroatom-doping reactions are essential to achieve advanced graphene-based materials for energy and biological areas. Unfortunately, considerably less is known regarding the detailed reaction pathways up to now. Here, we focus on investigating the nitrogen (N) doping process of fluorinated graphene (FG) under the assistance of defluorination based on modified in situ Fourier transform infrared spectroscopy. It was demonstrated FG possesses a higher and more effective reactivity with ammonia in comparison with other graphene derivatives, which enable N-doping to proceed efficiently with assistance of defluorination even at a lower temperature (16.8 at. % of N at 300 degrees C and 19.9 at. % of N at 400 degrees C). Combining with Density functional theory, it was proved that, at the initial reaction step of N-doping, ammonia molecule attacked and substituted the CF of FG by the new C-NH2. Sequentially, amino group was cyclized to the three-membered ring of ethylenimine. More importantly, the dissociation and migration of CF bonds facilitates the dissociating of CC bonds and the recombining of CN bonds, thus significantly promoting the N atom in ethylenimine ring to transform to the pyridinic-N or graphitic-N in graphene skeleton.