Precise engineering of ultra-thin Fe₂O₃ decorated Pt-based nanozymes via atomic layer deposition to switch off undesired activity for enhanced sensing performance

Unlike natural enzymes, nanozymes possess often multiple enzyme-mimic activities, which can be the impediment for their applications. Current strategies in activity engineering are based mainly on extensive cut-and-try screening and lack accurate engineering methods. It has not been reported through rational design to exaggerate the desired activity and suppress unwanted ones. In this study, inspired by catalytic theories in traditional nanocatalysis, ultra-thin Fe₂O₃ decorated Pt in inverse catalyst model (Fe₂O₃/Pt/CNTs) with high ratio of Pt⁰/Pt²⁺, new Pt-O-Fe³⁺ bonds and more interface sites was designed for excellent peroxidase activity and inhibited oxidase activity. Atomic layer deposition (ALD), as a novel approach for nanozyme preparation, enables the fine tailoring of surface microstructure of Fe₂O₃/Pt/CNTs. Activity analysis verified our design and the final Fe₂O₃/Pt/CNTs possess greatly enhanced peroxidase activity while the oxidase activity was eliminated. The detection limit of a colorimetric glucose sensor based on Fe₂O₃/Pt/CNTs was almost 10-fold lower over Pt/CNTs through the elimination of false-positive signal caused by the oxidase activity. These results demonstrated that, in virtue of the meticulous engineering method like ALD, rational design is feasible and powerful to engineer nanozymes with desired activity.