Boosting Enzyme-Like Activity Through Controlled Coordination of Metal Single-Atoms in Rhombic Cavity of Graphyne

The coordination number of metal single-atoms, being an important factor, should be precisely controlled as it affects both activity and specificity. Herein, the introduction of nitrogen into the para position of benzene in graphyne (2N-GY) is proposed as a carrier for anchoring metal single-atoms onto pyrazine nitrogen. These atoms are then coordinated to the center of the rhombic cavity, ensuring precisely controlled coordination numbers. Inspired by natural enzymes, a series of transition metal single-atom nanozymes (SANs) are constructed utilizing 2N-GY. Both theory calculations and experiments demonstrated that the incorporation of metal single-atoms of Fe, Mn, and Mo effectively augmented the enzyme-like activity, with Mo/GY exhibiting the highest peroxidase -like activity. Based on the differing activities of M/GY (M = Fe, Mn, Mo) and the varying abilities of sulfhydryl groups in biothiols to occupy metal active sites, sensing arrays for the high-throughput identification of six biothiols are constructed. After combining the fingerprint feature responses of biothiols and SANs with machine learning algorithms, the efficient distinction of the six biothiols is achieved. This study introduces a novel pathway for designing and synthesizing SANs that mimic natural enzymes.