Boosting the Catalase‐Like Activity of SAzymes via Facile Tuning of the Distances between Neighboring Atoms in Single‐Iron Sites
Hao Zhang, Pengbo Wang, Jingru Zhang, Qingdi Sun, Qian He, Xiaohui He, Hongyu Chen, Hongbing Ji
Abstract
Abstract A nanozyme with neighboring single‐iron sites (Fe 2 ‐SAzyme) was introduced as a bioinspired catalase mimic, featuring excellent activity under varied conditions, twice as high as that of random Fe 1 ‐SAzyme and ultrahigh H 2 O 2 affinity as that of bioenzymes. Surprisingly, the interatomic spacing tuning between adjacent iron sites also suppressed the competitive peroxidase pathway, remarkably increasing the catalase/peroxidase selectivity up to ~6 times compared to Fe 1 ‐SAzyme. This dramatically switched the catalytic activity of Fe‐SAzymes from generating (i.e. Fe 1 ‐SAzymes, preferably mimicking peroxidase) to scavenging ROS (i.e. Fe 2 ‐SAzymes, dominantly mimicking catalase). Theoretical and experimental investigations suggested that the pairwise single‐iron sites may serve as a robust molecular tweezer to efficiently trap and decompose H 2 O 2 into O 2 , via cooperative hydrogen‐bonding induced end‐bridge adsorption. The versatile mechano‐assisted in situ MOF capsulation strategy enabled facile access to neighboring M 2 ‐SAzyme (M=Fe, Ir, Pt), even up to a 1000 grams scale, but with no obvious scale‐up effect for both structures and performances.