Efficient screening of single-atom Porphyrazine-coordinated transition metal catalysts for electrochemical nitric oxide reduction: Insights from first-principles calculations

The electrochemical conversion of NO to NH3 is gaining attention in green energy for its dual benefits of producing ammonia and eliminating toxic NO. However, the lack of efficient and durable electrocatalysts limits its application, highlighting the need for improved catalysts to advance this promising strategy. The emerging transition metal porphyrazine frameworks (TM - Pz), which combine the advantages of single-atom metal (SAC) centers with the coordination of surrounding 4 N ligands, present promising opportunities in the field of electrochemical catalysis. We have designed a series of 3d transition metal single-atom catalysts (SACs) and conducted high-throughput screening, based on first-principles computations, to identify effective catalysts for the electrocatalytic conversion of NO to NH3. Our findings reveal that the Ti - Pz, Fe - Pz, and V - Pz nanosheets exhibit significantly lower UL values of -0.11, -0.24, and -0.31 V, respectively, when compared to the experimentally and theoretically determined criterion of -0.32 V. The correlation between limiting potentials (UL) and a specific descriptor (phi) is particularly significant for constructing a volcano plot, which illustrates the intrinsic properties of metal atoms in various TM - Pz series and their associated remarkable nitric oxide reduction reaction (NORR) performance. Among the range of nanosheets evaluated, the Ti - Pz and Fe - Pz models emerge as particularly noteworthy, demonstrating significantly higher selectivity and NORR activity than their counterparts. This research deepens our comprehension of the distinctive and advantageous properties of SACs, presenting progressive perspectives that can directly facilitate the discovery and optimization of SACs for NORR applications.