纳米Ag@SiO_2/TiO_2复合光催化剂的制备及性能研究

Preparation and property of Ag@SiO_2/TiO_2 nanocomposite photocatalyst

利用改进的Stber法在银核表面包覆一层SiO2,制备核-壳结构Ag@SiO2,然后以钛酸丁酯为钛源,采用溶胶-凝胶法制备出Ag@SiO2/TiO2复合光催化剂。应用XRD、TEM,UV-Vis和荧光光谱仪对样品进行表征。以亚甲基蓝作为降解模型化合物,研究所制备Ag@SiO2/TiO2复合材料的光催化性能。结果表明,由于贵金属Ag的存在,大大提高了TiO2的光催化效率;而Ag@SiO2结构,使得Ag的等离子共振峰明显向长波方向移动,与TiO2复合后,拓宽了TiO2的光谱响应范围,从而提高对可见光的利用率。

Ag@SiO2core-shell nanostructure was prepared using modified Stber method.Then Ag@SiO2/TiO2 was in-situ synthesized by sol-gel method,used tetra-n-butyl titanate as titanium source.The as-prepared samples were characterized with Xray diffraction（XRD）,transmission electron microscopy（TEM）,UV-Vis spectroscopy and fluorescence spectrophotometer.The degradation of methyl blue（MB）was used as the model reaction to investigated the photocatalytic property of the photocatalyst.The results showed that photocatalytic efficiency of TiO2 was improved greatly due to the presence of nano silver.In addition,the surface plasma absorption peak of silver moved to longer wavelengths after coating a layer of SiO2.So the photocatalyst broadened the spectral response range of TiO2 and increased the utilization rate of visible light.