Maximizing Accessible Fe‐N‐C Sites on Highly Curved Surfaces via Chemical Vapor Deposition for Boosting Multienzyme‐like Activities of Single‐Atom Nanozymes

Single‐atom nanozymes (SAzymes) have emerged as a highly promising class of next‐generation nanozymes. However, their widespread application remains significantly restricted by low reaction activity, primarily attributed to inefficient site utilization and sluggish reaction kinetics. Herein, we provided a novel approach to maximize accessible Fe‐N‐C sites on a highly curved surface through chemical vapor deposition. This innovative catalyst demonstrated superior multienzyme‐like activities compared to the conventional single iron atom catalyst (FeSA) with planar Fe‐N4 sites. Specifically, for peroxidase‐like activity, the hFeSA exhibited a maximal reaction velocity of 1.91×10‐7 M s‐1, a catalytic constant of 5.78 s‐1, and a specific activity of 177.5 U/mg, which were 9.67‐fold, 2.56‐fold, and 9.56‐fold higher than those of the conventional FeSA, respectively. Similarly, for oxidase‐like activity, the hFeSA achieved a maximal reaction velocity of 2.84×10‐7 M s‐1, a catalytic constant of 4.3 s‐1, and a specific activity of 76.27 U/mg, representing enhancements of 11.18‐fold, 2.97‐fold, and 12.01‐fold over FeSA, respectively. These results underscore the significant advantages of hFeSA in dramatically enhancing multienzyme‐like activities. Furthermore, theoretical calculations revealed that single iron atoms anchored on curved surfaces can effectively lower the energy barrier, thereby enhancing the intrinsic activity of the Fe‐N4 sites and accelerating reaction kinetics.