▎ 摘　　要

Deoxygenation and nitrogen-doping mechanisms of graphene oxides with participation of foreign NH3 molecules were investigated by density functional theory calculations. First, reduction on perfect graphene oxide without any structural defect is proved to be facilitated at high temperature, but the following doping process is impracticable because of the huge energy requirement for C-C cleavage. To elucidate the formation of hexagonal graphitic-N, we explored oxygen reduction and subsequent nitrogen-doping processes on defective graphene oxides with single vacancies for the first time. All possible reaction pathways were taken into account, and the results demonstrate that the formation of graphitic-N from NH3 and defective graphene oxides with one carbonyl or two hydroxyl groups is feasible in energy. The dominant reaction route is found to be exothermic with a practical reaction rate of 2.26 X 10(6) s(-1) at 900 degrees C, which is in a good agreement with experimental observations.