▎ 摘　　要

Due to its relatively high inertness, nitrogen dissociation at ambient temperature and pressure has always been a challenging task. Plasmon driven photocatalysis has proved to be an effective method. Owing to their unique physical, chemical, and electronic properties, two-dimensional planar materials have become the most promising candidates to replace noble metal catalytic nitrogen reduction. In this study, real-time dynamics of N-2 dissociation on graphene sheets under femtosecond laser irradiation was studied by using time-dependent density functional theory. We confirm that electrons generated by plasmon excitation of graphene transfer to the N-2 molecular antibonding orbital and activate the N-N bond. The threshold of laser intensity of N-2 dissociation can be effectively reduced by mixing CO molecules. This work provides basic insights for understanding the plasmon induced N-2 activation process at the atomic scale and proves that graphene can be used as one of the candidate materials for N-2 reduction photocatalysts with excellent performance.