SiO_2/TiO_2复合材料的制备及其光催化性能

Fabrication and Photoactivity of SiO_2/TiO_2 Composites

首先以P123(EO_(20)PO_(70)EO_(20))和PEG(聚乙二醇)为复合模板,制备了短棒状介孔SiO_2,然后采用电子转移催化剂再生-原子转移自由基聚合(ARGET ATRP)方法对其进行改性。以改性后的SiO_2为模板,以钛酸四丁酯(TBT)为钛源,制备了带有TiO_2壳的短棒状介孔SiO_2/TiO_2光催化剂复合材料。采用热重分析(TGA)、透射电子显微镜(TEM)、X射线衍射分析(XRD)、比表面和空隙分析仪对其进行了表征,通过甲基橙光降解反应研究了其光催化性能。结果表明:亲水性聚合物成功改性介孔SiO_2;锐钛矿相的TiO_2纳米粒子均匀分散在SiO_2表面;制得的SiO_2/TiO_2复合材料具有双峰孔结构;在可见光照射下,4.5 h后对甲基橙的降解率最高可达到99.5%,具有较高的光催化效率。

First of all,short rod-shaped mesoporous SiO2 was prepared using P123(EO20PO70EO20)and PEG(Polyethylene glycol)as dual templates,and then modified using activators regenerated by electron transfer-atom transfer radical polymerization(ARGET ATRP).Short rod-shaped mesoporous SiO2/TiO2 photocatalyst composites containing a TiO2 shell were synthesized by using modified SiO2 as templates and tetrabutyl titanate(TBT)as a titanium source.The obtained photocatalysts were characterized by thermogravimetric analysis(TGA),transmission electron microscopy(TEM),X-ray diffraction(XRD)and specific surface and void analyzer apparatus.The photocatalytic activity of the fabricated composite was then tested on methyl orange photodegradation.The results show that mesoporous SiO2 is modified by hydrophilic polymers,the anatase TiO2 species distribute on the outer surface of the SiO2,and the prepared SiO2/TiO2 has a bimodal nanoporous structure.Under visible light,the percentage of methyl orange degradation reaches approximately 99.5%after 4.5 h.