以直径300 nm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％.
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％.
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