Abstract: A SiO2/TiO2 composite photocatalyst was prepared by microemulsion method using inorganic polymerized silicate as the silicon source and titanium sulfate as the titanium source. The influence of preparation conditions on photocatalytic activity was investigated，and the photocatalyst was characterized by SEM，FTIR，XRD and BET. The results prove that a strong interaction exists between SiO2 and TiO2 particles，the formation of Ti—O—Si bond inhibits the TiO2 particle growth and also defers the transformation of TiO2 from anatast to rutile phase. The photocatalytic degradation of dyes，such as methyl orange，shows that the photocatalytic activity of SiO2/TiO2 is not improved along with higher propotion of TiO2. when the amount of substance ratio between Silicon and Titanium was 1∶1，and the photocatalyst was hydrothermal synthesized for 2.5 h at 160 ℃，the decoloration rate of methyl orange under UV light irradiation for 15 minutes over the SiO2/TiO2 photocatalyst could reach 85.5%，which has better photocatalytic activity and higher specific surface area than the TiO2 photocatalyst prepared under the same condition.

Key words: nanosized SiO2/ TiO2, photocatalysis, microemulsion, hydrothermal

摘要： 以无机物聚合硅酸为硅源、硫酸钛为钛源，采用微乳液法制备了SiO2/TiO2复合光催化剂，考察了制备条件对SiO2/TiO2光催化活性的影响，并利用SEM、FTIR、XRD和BET等技术手段对光催化剂进行了表征。结果证明，SiO2和TiO2颗粒之间存在着强的相互作用，形成了Ti—O—Si键，从而抑制了TiO2粒径的增大，延缓了TiO2由锐钛矿相向金红石相的转变。对甲基橙等染料的光催化降解实验结果表明，SiO2/TiO2的光催化活性并非随着TiO2的含量增加而提高，当硅与钛物质的量比为1∶1并在160℃的温度下水热合成2.5 h时，SiO2/TiO2光催化剂在紫外光照15 min后对甲基橙的脱色率为85.5%，与同等条件下制备的TiO2相比具有更好的光催化活性和更大的比表面积。

关键词: 纳米SiO2/ TiO2, 光催化, 微乳液, 水热