Journal of Applied Sciences and Nanotechnology

Different iron oxide nanoparticles (Fe₃O₄ and Fe₂O₃) were prepared by the sol-gel method (titration). The prepared nanoparticles were heated at 90 and 400°C. The morphology surface and structures were characterized by Fourier Transform Infra-Red (FT-IR) and Ultraviolet/Visible (Uv/Visible) measurements, X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), and Atomic Force Microscope (AFM). The enzyme mimetic activities of these nanoparticles (Fe₃O₄ and Fe₂O₃) such as two enzymes (Catalase (CAT), and Peroxidase (Pxase)) were measured. The results showed the iron oxides (Fe₂O₃) heated at 90°C, have the maximum activity (189.99 K.min^-1) as catalase (CAT). While the iron oxides (Fe₃O₄) heated at 90°C, have the maximum activity (3.044 U.min^-1) as peroxidase (Pxase), and there is a decrease in the activity for both nanoparticles when annealed at 400°C. Despite the average grain size decrease in both samples, however, the mimetic activity decrease that is mean the average grain size is not affected in both mimetic activities as catalase and peroxidase.