Synthesis And Properties Of Magnetic Multifunctional Nanoparticles Via Ferrocene Precursor Method

Among various magnetic materials, Fe3O4 nanoparticles have found applications in a wide range of fields, due to their high surface area, high magnetic susceptibility, environment benignity, chemical stability, and low toxicity. Development of multifunctional nanocomposites constituted with FesO4 nanomaterials is a new research trend in recent years. Nowadays, magnetic multifunctional nanoparticles are mainly prepared through the strategy of pre-synthesis and sequential assembly of component nanoparticles, being suffered by long preparation time, high cost, and unstable structures. Ferrocene is a commonly used inorganic reagent which can easily form stable Fe3O4/C nanocomposites under solvothermal condition. With ferrocene as a precursor, this thesis aims to develop new core-shell multifunctional nanoparticles with stable structures and explore their chemical/physical properties. The main contents are as follows:Firstly, we developed a convenient approach to prepare core-shell-shell Fe3O4@C@CdS composite photocatalysts. Through one-step solvothermal carbonization of ferrocene, we obtained uniform core-shell Fe3O4@C nanoparticles which not only could serve as magnetic cores but also adsorb Cd2+ions for the deposition of CdS nanocrystals. As a result, the prepared Fe3O4@C@CdS nanocomposites exhibited uniform sizes, regular shapes and stable structures. Assessed by the photodegradation of organic dyes, these Fe3O4@C@CdS nanocomposites showed good photocatalytic activity and reusability.Secondly, we promoted a facile method to synthesize ZnFe2O4@C@ZnO hollow spheres using Fe3O4@C as precursors. Through solvothermal carbonization of ferrocene on SiO2 spheres, we obtained uniform SiO2@Fe3O4@C nanoparticles and then Fe3O4@C hollow spheres by etching SiO2 under hot alkali condition. Because of the slow reaction between solid Fe3O4 and Zn2+ ions and adsorption of carbon layer, we prepared ZnFe2O4@C nanoparticles covered with a layer of ZnO, leading to the formation of magnetic semiconductor heterojunction. At the same time, the compositions of ZnFe2O4@C@ZnO nanoparticles could be conveniently controlled. The prepared hollow spheres were uniform in size and shape, dispersive in water and strong in magnetization. Furthermore, they showed promising applications in the photodegradation of dye and detection of glucose.Finally, we developed a novel yolk-shell upconversion/C/Fe3O4 composite nanostructure. Through solvothermal carbonization of ferrocene with NaYF4@SiO2 templates, we obtained three-shell-structured nanostructures and then etched off the SiO2 shell. The developed NaYF4@Fe3O4@C nanoparticles had an obvious yolk-shell structure and showed enhanced upconversion emissions. Since these yolk-shell nanoparticles were able to load fluorescent dyes to receive energy from the upconversion cores, they had been successfully employed in the detection of heavy metal ions. Using zincon monosodium salt (ZMSS) as an example, these yolk-shell nanoparticles could be utilized to the detection of Cu2+ ions with high sensitivity and specificity. Moreover, the metal ions could be enriched in the nanoparticles and then removed by the magnetic collection.