Preparations, Characterizing And Applications Of Core-shell Nano-particles

Nano-zine and nano-titanic dioxide as a new type of inorganic functional materials were widespread attention by its superior performance. But the nanometer materials were easy to reunite, its influenced on performance, moreover nanometer zinc oxide and titanium dioxide high photocatalytic activity, which also limit the application of in some areas, therefore, nanometer zinc oxide and titanium dioxide with surface modification to improve its dispersion, inhibit the photocatalytic activity, and make the nanometer zinc oxide and titanium dioxide can be applied widely.Zinc oxide and titanium dioxide were respectively prepared by hydrothermal and homogeneous precipitation method. By adjusting reaction temperature, concentration of reactants, reactant ratio, pH value and reaction time to control the growth of particle size. Using liquid phase heterogeneous nucleation coating method, by adjusting the reaction temperature, concentration of reactants, reaction time, reactant ratio and pH value, found the best coated conditions. The X-ray diffraction(XRD) and scanning electron microscopy(SEM) were analyzed morphology observation of the products; The size distribution were tested by particle size distribution measurement instrument; Through the settlement of suspension to measure the dispersability of particles in water The ultraviolet ability of coated powders were tested by uv-vis spectrophotometer.Through the characterization, found that particle size of zinc oxide and titanium dioxide which were prepared by homogeneous precipitation method were relatively more bigger in nanoparticles crystal type than Hydrothermal, but the particle size distribution were narrow, better dispersion which were prepared by hydrothermal. The effect of the reaction temperature, concentration of reactants, reaction time and reactant ratio to particle size was different. Through experiments showed that, the particle surface subsidence coated silica which changed particle shape, made the particle size distribution was narrow and greatly improved the dispersion of the powders in aqueous solution. Ultraviolet absorption experiments show the surface of the zinc oxide and titanium dioxide nanoparticles were coated by porous silica, also have a superior shielding ability to ultraviolet ray, and intensify the visible light transmittance.