Preparation, Characterization And Applications Of Sliver Loaded Fe3O4Nanocomposites

The nanocomposites that contain two or more different nanosized functional composites are attractive for candidates for advanced nanomaterials. Dimer or oligomer heterostructues composed of individual components with different nanosized properties give rise to combination of unique properties. The Fe3O4magnetite nanoparticles have long been one of the most promising materials because of easy preparation, low toxiciry, their good biocompatibility and strong superparamagnetic property, which have been great potential for various applications, such as biomedical, catalysis and so on. Silver nanoparticles have also been developed in catalysis field, especially in bioelectrocatalysis and electrocatalysis. We adopted the core-shell architecture based on silica matrix, for its high hydrophile, optically transparent, easy preparation. Moreover, SiO2matrix is the appropriate support material for Ag nanoparticles. In this paper, the novel nanocomposites using SiO2as a surport, which combined of Fe3O4and silver nanoparticles into a single microcomposite system and their properties were also studied. Therefore, we can invent more significative functional materials by utilizing synthetically the surface properties of silver nanoparticle and magnetic properties of magnetic nanoparticles.This dissertation consists of four chapters:Chapter1:This part generally introduced classification, main synthesis strategies and properties of silver nanopartiles, Fe3O4nanoparticles. Their applications were summarized.Chapter2:Novel bifunctional core-shell nanoparticles Fe3O4@SiO2-Ag have been developed using a modified Stober method combined with a simple electroless deposition method. The resultant bifunctional nanoparticles are superparamagnetic behavior, which can be easily recycled by applying an external magnetic field. Furthermore, they exhibit powerful catalytic activity for the reduction of p-nitrophenol. In addition, due to their unique structure, the as-obtained products may have potential applications in water treatment, sensors, microelectronics, energy storage.Chapter3:Fe3O4@SiO2/Ag was synthesized by the Ag-mirror reaction. This method was found to be mild, inexpensive, green, convenient and efficient. In this part, we studied the mechanism of the formation of the Fe3O4@SiO2/Ag nanocomposites. Meanwhile, the catalytic property of the composites was tested by catalytic reduction of Methylene Blue, the mechanism of catalytic reduction was also discussed.Chapter4:Using Fe3O4@SiO2/Ag magnetic nanoparticle as a non-enzyme bisensor to detect H2O2. The biosensor has exhibited excellent electrocatalytic activity to the reduction of H2O2by cyclic voltammetry (CV) without the aid of an electron mediator. The results indicated that Fe3O4@SiO2/Ag was stably immobized on the GC electrode.The contribution of this paper was two kinds of catalytic magnetic nanomaterials has been developed integrating the magnetic core with Ag nanoparticles. The formation mechanism of composite nanoparticles and the catalytic mechanism were also studied. The nanocomposites possess both superparamagnetic and catalytic behavior, as well, they can be reused. The nanocomposites have potential applications in chemistry, biomedicine and environment research, and so on.