▎ 摘　　要

Nitrogen-doped graphene supported single metal atoms are expected to achieve high nitrogen reduction reaction (NRR) performance via the electroreduction process. Based on density functional theory (DFT) calculations, the application of three pyrrolic-N doped graphene (pyrrolic-N-3-G) supported V-1, Cr-1, Mn-1, Fe-1, Nb-1, Mo-1, W-1 and Re-1 as electrocatalysts for NRR is evaluated from stability, limiting potential and ammonia selectivity points of view. Mo-1(W-1, Re-1)/pyrrolic-N-3-G are predicted to be potential candidates for NRR with high stability, less negative limiting potential (-0.49, -0.33 and -0.51 V) and high ammonia selectivity, which indicates that the catalytic performances are improved from both activity and selectivity aspects compared to the corresponding pyridine-N-3-G supported ones. The identified descriptors indicate that the accumulated charges on metal atoms and the adsorbed hydrogen atoms have considerable impacts on limiting potential and selectivity, respectively. It is also suggested that the NRR activity can be tuned by changing the coordination environment and the response of changing coordination environments differs according to the type of transition metals.