Transition metals decorated holey graphyne as a potential catalyst for electrocatalytic nitrogen reduction to ammonia

Single-atom catalysts (SACs) supported on two-dimensional carbon-based materials offer a sustainable alternative to the Haber-Bosch process for ammonia production via electrocatalytic nitrogen reduction (eNRR). First-principles density functional theory simulations were employed to investigate transition metal-decorated holey graphyne (TM@HGY; TM: Sc, Cu, Mo, Ru) SACs for eNRR. Interaction energy and ab initio molecular dynamics simulations confirm their thermodynamic and thermal stability (300–500 K). Bader charge analysis reveals electron transfer of 0.50–1.53e from TMs to HGY, while density of states and electron localization function analyses indicate metallic conductivity and efficient charge delocalization. N [tbnd]N bond elongation (1.11–1.19 Å) shows effective N₂ activation over the designed catalysts. Gibbs free energy profiles identify Ru@HGY as the most active catalyst, requiring −0.54 V of applied potential for both alternating and distal pathways. All SACs demonstrate Remarkable suppression of the hydrogen evolution reaction with substantial potential (−0.80 V to −1.26 V), ensuring high selectivity for ammonia production.