Nanozyme-Modified Metal-Organic Frameworks with Multienzymes Activity as Biomimetic Catalysts and Electrocatalytic Interfaces.

Many metal-organic frameworks have been designed and synthesized for biosensors because of high surface area and porosity, suitable size, and good biocompatibility. Despite recent advances, however, most of them are only used as a nanocarrier. In this work, a new artificial nanozyme was constructed on a metalloporphyrinic metal-organic framework (PMOF(Fe)), which was formed by Fe porphyrin and Zr4+ ions. Then, ultrasmall Pt nanoparticles (Pt NPs) were loaded on the surface of PMOF(Fe) to form Pt@PMOF(Fe). Because of the high surface area and exposed Fe activity center, PMOF(Fe) works as a nanocarrier to hinder the Pt NP aggregation and exhibits high peroxidase-mimicking activity. Hence, Pt NPs decorated on the surface of PMOF(Fe) possessed high stability and exhibited high activity. Due to the synergistic effect between PMOF(Fe) and Pt NPs, Pt@PMOF(Fe) exhibits superior catalase- and peroxidase-like activities. Moreover, Pt@PMOF(Fe) possesses high electrocatalytic activity toward the reduction of H2O2 and the oxygen reduction reaction (ORR). This strategy may serve as a strong foundation to design MOF-based artificial nanozymes and develop an ideal platform for MOFs and nanozymes toward artificial enzymatic catalytic systems, fuel cells and new analytical applications.