Preparation and a new method to determinate catalase mimics activity of MnO2, Fe2O3 and MnO2:Fe2O3

A new colorimetric method was used to determine catalase mimic activities of MnO2 nanoparticles against hydrogen peroxide (as substrates), by using a new method (acidic solution of potassium permanganate). Manganese dioxide (MnO2) and iron oxide (Fe2O3) nanoparticles were prepared by a hydrothermal method. We annealed MnO2 at different temperatures (250-700°C). MnO2: Fe2O3 composite were prepared in the mole ratio of 3:1 the annealed at 400°C. The structures of these nanoparticles and the surface morphology were characterized by FT-IR measurements, X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), and Atomic Force Microscope (AFM). Our results found this new method succeed to determine catalase mimic activity and the annealing at 400°C is the best sample activity of MnO2, while the catalase mimic activity of the composite was decreased compared with MnO2 activity alone in the same annealing temperature.