Zirconium-doped iron oxide nanoparticles for enhanced peroxidase-like activity

Fe₃O₄ nanoparticles (NPs) have emerged as pioneering nanozymes with applications in clinical diagnosis, environmental protection and biosensing. However, it is currently limited by insufficient catalytic activity due to poor electron transfer. In this study, we synthesized electron-rich-Zr-doped defect-rich Fe₃O₄ NPs (Zr₃Fe₃O₄) using a one-pot solvothermal method. Compared with intrinsic Fe₃O₄ NPs, the resultant Zr₃Fe₃O₄ NPs exhibit enhanced peroxidase (POD)-like activity attributed to the presence of active centers of Zr-O-Fe bridges and adsorption sites of asymmetric oxygen vacancies (OVs) Zr-OVs-Fe. The Zr-O-Fe bridges facilitate electron transfer from Zr to Fe, promoting the regeneration of surface Fe²⁺ in Fe₃O₄ NPs. Furthermore, the rich Zr-OVs-Fe significantly enhances the adsorption and electron transfer between catalyst and substrates, thereby regulating the generation pathway of ¹O₂. Leveraging the remarkable POD-like activity of Zr₃Fe₃O₄ NPs, we developed a tandem enzyme-catalyzed reaction for colorimetric detection of glucose. This strategy of constructing active centers by atom doping provides valuable guidance for the development of more efficient Fenton-like catalytic systems with broad applications on a large scale.