Tetrahedral W4 cluster confined in graphene-like C2N 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 C2N (denoted as W-4@C2N). Our results demonstrate that N-affinity of active sites on W-4 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 W-4@C2N 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@C2N, which demonstrated sufficient thermal stability and electric property for electrode application.