Preparation And Further-functionalization Of Metal Nanoparticles/silica Composites Based On Self-catalytic Recation

In recent decade, metal particles/silica nanocomposites have drawn much attention duo to their unique physiochemical properties compared to their bulk counterparts and their controllable nanostructures and designablility. Among various nanoparticles, metal nanoparticles have excellent performance in catalyst, sensor, energy storage and conversion, optics, electricity and magnetism and applications in many fields, which make them play important roles in functional materials. The properties of materials are not only decided by the nature of the composition but also related to synthesis methods and materials nanostructures. Thus, the creation of the synthesis methods and controllable structure of metal particles/silica nanocomposites are not only the technological frontier and focus of researches, but an important fundamental research work.In this paper, we presented a facile and novel method to synthesize metal particles/silica nanocomposites based on successive spontaneous self-catalytic reactions at near neutral condition. our typical study is no need to add extra acid or basic catalyst, using the catalytic sites coming from intramolecular to catalytic silicon hydrolyzation and condensation reaction. We designed multifunctional precursors molecular, establishing a new synthesis method of organic metal salt/silica nanocomposites, and achieved the purpose for preparing the metal particles or metal oxide particles in silica matrix in situ, as well as through the further-functionalization means, which made us successfully synthesize multifunctional silica nanocomposites. The morphology and nanostructure of materials were characterized by the means of Scanning Electron Microscope(SEM), Transmission Electron Microcopy(TEM), X-ray Diffraction(XRD), Fourier Transform Infrared Spectroscopy(FT-IR), Nuclear Magnetic Resonance Spectroscopy(1H-NMR), N2 Adsorption-Desorption Isotherms and Ultraviolet-visible Spectrum(UV-Vis). The properties of materials were tested by Fluorescent Excitation-emission Spectra, Fluorescent Microcopy and Magnetic Hysteresis LoopIn our first study, cadmium oxide and amino acids were used to synthesize amino-acid metal salt, and then reacted with Teraethyl orthosilicate(TEOS) in mixture solution of water and ethanol at room temperature, after centrifuging and dried in vacuum drying oven, we acquired metal particles/silica nanocomposites by the means of thermal treatment. We endowed the materials fluorescence property through vulcanization, and explored the formation of these nanocomposites at different experience conditions. The results shows that we successfully synthesized Cd S/Si O2 nanocomposites with the Cd S nanoparticles uniformly dispersed in Si O 2, this nanocomposites have good fluorescence characteristic; In our second study, cobalt carbonate and bromoacetic acid were used to organic metal salt first, and then reacted with 3-Aminopropyltriethoxysilane(APTES) and TEOS in mixture water/ethanol solution at room temperature, centrifuged and dried. We further-functional this type of materials by means of taking full use of all chemical reaction sites to make materials with good catalyst property. Finally we got nanocomposites with two metal phase coated with silica matrix after calcination. We characterized by series testing ways and demonstrated that we successfully synthesized Ag-Co3O4/Si O2 nanocomposites, the nanoparticles uniformly dispersed in Si O2 matrix. And the nanocomposites have excellent catalytic performance and Magnetic separation.