中文摘要：

以直径300nm左右的SiO2微球为核,采用溶胶-凝胶法制备了SiO2/TiO2核壳结构光催化剂,并以化学还原法对其进行Pt沉积。采用XRD、XPS、TEM、DRS、PL对制备样品进行表征。结果表明,Pt主要以Pt（0）形式存在,不均匀地分布在SiO2/TiO2表面。Pt的沉积使得光催化剂在可见光区域的光吸收增强,电子与空穴分离效率明显提高。测定了罗丹明B在不同光催化剂上的吸附常数。结果表明,核壳结构有利于罗丹明B在光催化剂表面的吸附,沉积Pt可显著提高光催化降解反应的动力学常数。Pt的最优沉积量为0.5%。

英文摘要：

SiO2/TiO2 photocatalyst with core-shell structure were synthesized by sol-gel method, using SiO2 microsphere with a mean size of about 300 nm as template. And then Pt was deposited on SiO2/TiO2 by chemical reduction method. The obtained samples were characterized by X-ray diffraction （XRD）, transmission electron microscopy （TEM）, diffuse reflectance spectra （DRS）, X-ray photoelectron spectroscopy （XPS）, and photoluminescence spectra （PL）. The results show that Pt particles mainly in form of Pt（0） can be deposited on SiO2/TiO2 surface un-uniformly. The absorption in visible light region and the separation efficiency of electron-hole pairs are enhanced obviously via Pt-deposition. The adsorption and kinetic constants of Rhodamine B （RB） over the obtained samples were evaluated. The results indicate that core-shell structure is helpful to improve the adsorption property. The presence of Pt on SiO2/TiO2 surface is found to significantly enhance the photodegradation of RB, and the optimal deposition of Pt is 0.5 wt%.