Effect of N-doping on graphene: NRR activity and N-source

The N-doped graphene has attracted significant research interests in the catalysis fields, however, the usage of N-doped graphene in the nitrogen reduction reaction (NRR) electrocatalysts is limited owing to its unclear effect on the electrocatalytic procedures that are whether there be polluted ammonia (NH3), and its NRR performance is unknown. In this work, the effect of N-doped graphene on the NRR is explored by the density functional theory (DFT). The results show that the N-doped graphene does not present NRR performance, and the graphene with graphitic-N and pyridine-N can catalyze the competitive hydrogen evolution reaction (HER). More important, the pyrrole-N in graphene would be converted into the polluted NH3. Therefore, the N-doped graphene is not suitable as the NRR electrocatalysts and the supporting materials. The work guides the design of NRR electrocatalysts and accurate measurement of NRR performance for N-doped graphene/N-doped graphene composites.