Site-Defined High-Loading Tellurium Single-Atom Nanozymes Anchored on Checkerboard-Patterned Graphyne for Sensor Array Construction

Single-atom nanozymes exhibit unique enzymatic activity due to their active centers, which resemble those of natural metalloenzymes. The design of the anchoring sites of single-atom active centers is an important factor that affects the loading capacity and catalytic activity. Herein, para-nitrogen-doped graphyne with diamond cavity is used as support, and single-atom tellurium atoms are then anchored in the nitrogen-containing graphyne cavities, akin to chess pieces placed on a chessboard grid. Due to the pre-designed regular anchoring sites, the site-defined tellurium single-atom nanozyme (Te SAN) achieves a high Te loading of 19.21 wt.%. Therefore, Te SAN shows good peroxidase-like activity. To explain the enhanced peroxidase-like activity, density functional theory calculations are performed and the results demonstrate that Te doping enhances catalytic activity by lower Gibbs free energy barrier for formation of •OH, a key intermediate in peroxidase-like activity. Finally, based on the inhibitory effect of bisphenols on nanozyme activity, the Te SAN-based sensor array successfully identifies five bisphenols, holding potential for on-site food safety monitoring. The design of the anchoring sites of single atoms in this work provides new ideas for precisely controlling the synthesis of nanozymes, exploring their action mechanisms, and enhancing their activities.