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. © 2025