Boosting the Catalase‐Like Activity of SAzymes via Facile Tuning of the Distances between Neighboring Atoms in Single‐Iron Sites

Abstract

AbstractA nanozyme with neighboring single‐iron sites (Fe2‐SAzyme) was introduced as a bioinspired catalase mimic, featuring excellent activity under varied conditions, twice as high as that of random Fe1‐SAzyme and ultrahigh H2O2 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 Fe1‐SAzyme. This dramatically switched the catalytic activity of Fe‐SAzymes from generating (i.e. Fe1‐SAzymes, preferably mimicking peroxidase) to scavenging ROS (i.e. Fe2‐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 H2O2 into O2, via cooperative hydrogen‐bonding induced end‐bridge adsorption. The versatile mechano‐assisted in situ MOF capsulation strategy enabled facile access to neighboring M2‐SAzyme (M=Fe, Ir, Pt), even up to a 1000 grams scale, but with no obvious scale‐up effect for both structures and performances.