New insights into the long-range interaction mechanism of nitrogen reduction

Abstract

Catalysts with asymmetric coordination exhibit excellent electrocatalytic activity due to changes in the active sites, which affect the arrangement of reactants and catalytic activity/selectivity. Hence, the exploration of the inherent characteristics of active sites within diverse coordination environments holds great significance for the experimental design of catalytic structures. Single-atom catalysts (SACs) characterized by high coordination with four carbons (26 candidates) and low coordination with dinitrogen (27 candidates) are constructed using nitrogen-doped graphdiyne derivatives (NGDY) as the substrate. Additionally, 5 species of dual-atom catalysts (DACs) with coexistence of both high and low coordination sites are also developed and their nitrogen reduction reaction (NRR) activities are systematically investigated by density functional theory. The results indicate that metals with low coordination exhibit superior catalytic performance, such as Mo^L-NGDY (U_L =  −0.30 V) and Nb^L-NGDY (U_L =  −0.32 V). Furthermore, machine learning (ML) methods have deeply analyzed and elucidated the primary intrinsic characteristics that influence catalytic performance. These results not only unveil the underlying mechanisms behind the exceptional catalytic performance exhibited by low-coordination metal atoms, but also provide relevant and significant descriptors. More importantly, based on an investigation of the catalytic activity of a series of DACs, the “buffer and low-coordination accumulate” asymmetric coordination mechanism is proposed to unveil the long-range interactions between low and high coordination atoms. Due to this remote communication, MoNb-NGDY (U_L =  −0.09/−0.37 V) exhibits the best NRR activity. This mechanism provides valuable insights into the origin of long-range bipartite interactions and inspires the design and synthesis of NRR catalysts with different coordination environments.