LAUSR

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 W4 tetrahedron embedded in graphene-like C2N (denoted as W4@C2N). Our results demonstrate that N-affinity of active sites on W4 dominate over single-atom site, rendering *NH2 + (H+ + e−) →*NH3 invariably the potential-determining step (PDS) of eNRR via consecutive or distal route (U L = −0.68 V) to ammonia formation. However, *NHNH2 + (H+ + e−) →*NH2NH2 has become the PDS (U L = −0.54 V) via enzymatic route towards NH2NH2 formation and thereafter desorption, making W4@C2N a potentially promising catalyst for hydrazine production from eNRR. Furthermore, eNRR is competitive with hydrogen evolution reaction (U L = −0.78 V) on W4@C2N, which demonstrated sufficient thermal stability and electric property for electrode application.