Preparation And Chracterization And Peroxidase-like Activity Of Iron Series Nanostructure

Since first report on the intrinsic peroxidase-like activity of ferromagneticnanoparticles by Gao and his partners in2007, various nanomaterials, such as CoFe2O4、Pt、FeS nanoparticles have been found to possess catalytic activity of enzyme mimeticies.Previous reports demonstrated that, one can be obtained nanoparticles in differentcompositions and different morphologies with different synthetic method to meet specificcatalytic purposes. In view of this， this thesis is focused on the construction of newnanomaterials peroxidase mimetics and analytical applications of peroxidase mimetics. Themain contents are as follows:1. With a facile solvothermal and photochemical routes, spherical particles withdifferent diameter of Fe3O4-Ag nanocomposites were successfully prepared. The preparedsamples were characterized by scanning electron microscopy (SEM), transmission electronmicroscopy (TEM) and x-ray diffractometer (XRD). In contrast with Fe3O4nanoparticles,Fe3O4-Ag nanocomposites exhibit enhanced peroxidase-like activity. The optimization ofpH and H2O2concentration was3.6and0.2mM. And the smaller the size, the higher thecatalytic activity. The catalysis by Fe3O4-Ag nanocomposites were fitted to the Michaelis–Menten model.2. Combination of polyol method and solvothermal method Ag@Fe3O4nanowire weresuccessfully prepared. The Ag@Fe3O4nanowire has length of20-50μm, and diameter ofabout400nm, while Fe3O4nanoparticles were coated on the surface Ag nanowires. Wefound that the Ag@Fe3O4catalysed the reaction of the substrate3,3’,5,5’-tetramethylbenzidine (TMB) in the presence of H2O2to produce a blue colourreaction with maximum absorbance at652nm, showing a high peroxidase-like activity. Theoptimization of pH and H2O2concentration was5.0and0.1mM respectively. The result ofkinetic analysis indicates that the catalyzed reaction followed a Michaelis-Menten behavior.H2O2could be detected with a linear range from3×10-6to1×10-4mol/L.3. FePO4·2H2O nanostructures were prepared by solvothermal method, with PVP assurfactant, Fe(NO3)3·9H2O and H3PO4as the sources of iron and phosphorus, respectively.FePO4·2H2O nanostructures with different morphologies were obtained by controlling thereaction conditions. For example, nanoflowers assembled by nanosheets, honeycombednanoellipsoids, decanedron, nanosheets, nanorods and so on. XRD shows that all preparedsamples were monoclinic system. The colorimetric reaction of the nanoflowers is the mostobvious, so the sample of nanoflower is the emphasis. We found that the FePO4·2H2Onanoparticles also have the peroxidase-like activity. The optimization of pH, H2O2concentration were also carried out.