多孔SiO2与TiO2复合纳米材料的制备及光催化性能

在溶胶水热法所合成的锐钛矿相TiO₂纳米晶基础上，利用模板剂调制的SiO₂溶胶进一步合成了多孔SiO₂与TiO₂复合纳米粒子，重点研究了复合SiO₂对纳米锐钛矿相TiO₂热稳定性及光催化活性的影响.结果表明，复合SiO₂提高了纳米锐钛矿相TiO₂的热稳定性，经过900℃热处理后的TiO₂仍然具有以锐钛矿相为主的相组成.在光催化降解罗丹明B实验过程中，经过高温热处理的复合纳米材料表现出优于Degussa P25 TiO₂的活性，这主要与其锐钛矿相结晶度提高和具有较大比表面积等有关.

Preparation of Porous SiO2-TiO2 Nanocomposites and Their Photocatalytic Activity

Porous SiO₂-TiO₂ nanocomposites were synthesized by utilizing TiO₂ nanopartilces obtained by a sol-gel method, followed by an impregnation process with F127 modified SiO₂ sol. The resulting samples were characterized by XRD, BET, TEM, N₂ adsorption desorption, UV-Vis DRS spectra and FT-IR spectra, and their photocatalytic activities were also evaluated by degrading RhB solution under illumination. The effects of the SiO₂ on the thermal stability and photocatalytic activity of anatase nanoparticles were mainly investigated. The results show that the SiO₂ can greatly enhance the thermal stability of TiO₂ crystallities, even having a principal anatase phase composition after heat treated at 900℃, and make TiO₂ maintain a small crystallite size. The large surface area of the resulting SiO₂-TiO₂ nanocomposites is attributed to the small crystallite size and porous SiO₂. During the processes of photocatalytic degradation RhB, all the as prepared SiO₂-TiO₂ nanocomposites by thermal treatment at high temperature exhibit higher activity than Degussa P-25 TiO₂. The high activity is attributed to the high anatase crystallinity and the large surface area.