Screened Ni₃ single-cluster catalyst supported on graphidyne for high-performance electrocatalytic NO reduction to NH₃: A computational study

Electrocatalytic NO reduction (NORR) to NH₃ represents a promising approach for converting hazardous NO waste gases into high-value NH₃ products under ambient conditions. However, exploring stable, low-cost, and highly efficient catalysts to enhance the NO-to-NH₃ conversion process remains a significant challenge. Herein, through systematic computational studies based on density functional theory (DFT), we rationally designed transition metal triatomic cluster supported on graphdiyne (TM₃/GDY) as potential single-cluster catalysts for high-performance NORR. The results indicated that the GDY support is incredibly effective at immobilizing these triatomic metal clusters, preventing metal aggregation and dissolution. Furthermore, the TM₃/GDY systems exhibit tunable reactivity for NO activation due to the synergistic effect of triple-metal sites. Among all examined candidates, Ni₃/GDY demonstrates the highest NORR catalytic performance with a record low limiting potential of -0.05 V. Notably, NO adsorption strength was identified as an effective descriptor to rationalize the NORR activity trend, which is highly dependent on the amount of the carrying charges on the anchored TM₃ clusters. Additionally, the hydrogenation steps during NORR are kinetically feasible on Ni₃/GDY with a small kinetic barrier of 0.34 V for the rate-determining step, corresponding to an outstanding turnover frequency (3.03 × 10^-25) s^-1 per site at 300 K for NH₃ generation, implying an ultra-fast reaction rate. Our work not only identified promising NORR catalysts but also provided valuable insights for rationally designing atomically precise novel catalysts for the resource utilization of small molecules.