▎ 摘　　要

The catalytic reduction of N-2 to NH3 under mild condition remains as a challenging and important chemical process. By performing first-principle density functional theory calculations, the fixation and catalytic reduction of N-2 are investigated over a single Co atom supported defective N-doped graphene (Co/N-3-Gr) for the first time. All the distal, alternating and enzymatic mechanisms are investigated for the N-2 activation and its conversion to ammonia. Our findings reveal that Co/N-3-Gr exhibits high catalytic performance for the low-temperature electrochemical reduction of N-2 through the enzymatic mechanism. According to our results, the hydrogen evaluation reaction cannot proceed in parallel with the N-2 reduction, due to its relatively large over potential (eta).