Atom-pair engineering of single-atom nanozyme for boosting peroxidase-like activity

Constructing atom-pair engineering and improving the activity of metal single-atom nanozyme (SAzyme) is significant but challenging. Herein, we design the atom-pair engineering of Zn-SA/CNCl SAzyme by simultaneously constructing Zn-N₄ sites as catalytic sites and Zn-N₄Cl₁ sites as catalytic regulator. The Zn-N₄Cl₁ catalytic regulators effectively boost the peroxidase-like activities of Zn-N₄ catalytic sites, resulting in a 346-fold, 1496-fold, and 133-fold increase in the maximal reaction velocity, the catalytic constant and the catalytic efficiency, compared to Zn-SA/CN SAzyme without the Zn-N₄Cl₁ catalytic regulator. The Zn-SA/CNCl SAzyme with excellent peroxidase-like activity effectively inhibits tumor cell growth in vitro and in vivo. The density functional theory (DFT) calculations reveal that the Zn-N₄Cl₁ catalytic regulators facilitate the adsorption of ^*H₂O₂ and re-exposure of Zn-N₄ catalytic sites, and thus improve the reaction rate. This work provides a rational and effective strategy for improving the peroxidase-like activity of metal SAzyme by atom-pair engineering.