Theoretical investigation of graphdiyne-supported single-cluster catalysts for electroreduction of nitric oxide

The electrochemical NO reduction reaction (NORR) to NH₃ offers an efficient, environmentally friendly strategy for NO removal and NH₃ production, but developing effective catalysts to facilitate the conversion of NO into NH₃ remains a challenge. Single-cluster catalysts (SCCs) with multi-metallic sites show promise due to the synergistic interactions among the active atoms. Herein, utilizing density functional theory (DFT) and grand-canonical DFT (GC-DFT), we systematically investigated the potential of late transition metal (TM = Fe, Co, Ni, Cu, Ru, Rh, Pd, Pt) clusters on graphdiyne (TM_x/GDY, x = 1–5) for NORR. Ni₃/GDY, Pd₃/GDY, and Pt₃/GDY emerged as the most promising candidates, demonstrating stability, excellent NORR activity, and HER suppression. Their outstanding performance is attributed to the moderate adsorption of NO, with the d_xz/d_yz orbitals playing a key role in NO activation. GC-DFT results highlight nonlinear variation of intermediate grand free energies with the applied potential. Detailed electronic property analyses were conducted to reveal the charge effects induced by the applied chemical potential. This study provides valuable insights into SCC-catalyzed NO reduction and highlights the significance of potential effects in theoretical simulations of electrochemical systems.