Tetrahedral W 4 cluster confined in graphene-like C 2 N enables electrocatalytic nitrogen reduction from theoretical perspective.

Exploring the format of active site is essential to further the understanding of an electrocatalyst working under ambient conditions. Herein, we present a DFT study of electrocatalytic nitrogen reduction (eNRR) on W 4 tetrahedron embedded in graphene-like C 2 N (denoted as W 4 @C 2 N). Our results demonstrate that N-affinity of active sites on W 4 dominate over single-atom site, rendering *NH 2  + (H +  + e - ) →*NH 3 invariably the potential-determining step (PDS) of eNRR via consecutive or distal route ( U L  = -0.68 V) to ammonia formation. However, *NHNH 2  + (H +  + e - ) →*NH 2 NH 2 has become the PDS ( U L  = -0.54 V) via enzymatic route towards NH 2 NH 2 formation and thereafter desorption, making W 4 @C 2 N a potentially promising catalyst for hydrazine production from eNRR. Furthermore, eNRR is competitive with hydrogen evolution reaction ( U L  = -0.78 V) on W 4 @C 2 N, which demonstrated sufficient thermal stability and electric property for electrode application.