双亲性w/o-SiO2-void-TiO2中空核壳微球的合成及表征

采用双层包裹–夹层去除法合成了SiO₂-void-TiO₂中空核壳微球, 通过正十八烷基三甲氧基硅烷对SiO₂-void-TiO₂微球表面进行部分修饰, 制得了双亲性w/o-SiO₂-void-TiO₂中空核壳微球, 并采用XRD、TEM、BET、FT-IR和UV-Vis DRS等对样品的晶相结构、形貌、表面结构和吸光性能等进行了表征。以染料亚甲基蓝模拟环境污染物, 考察了SiO₂-void-TiO₂和w/o-SiO₂-void-TiO₂在紫外光下的光催化性能。结果表明: SiO₂-void-TiO₂样品呈微球状, 具有明显的核–多孔壳结构, 在核与多孔壳层之间存在纳米空间层, 样品中TiO₂核具有锐钛矿结构; w/o-SiO₂-void-TiO₂样品具有双亲性, 能分布于水/油两相界面处。在紫外光照射下, 反应180 min, SiO₂-void-TiO₂和w/o-SiO₂-void-TiO₂对亚甲基蓝的降解率分别达89.4% 和83.8%。在此基础上, 本研究探讨了SiO₂-void-TiO₂中空核壳微球的合成机理及表面部分改性机理。

Preparation and Characterization of Amphiphilic w/o-SiO2-void-TiO2 Core-shell Microspheres

SiO₂-void-TiO₂ core-shell microspheres were successfully prepared via double-coating with polyfurfuryldehyde and silica, and then removing the mid-layer to create a nanovoid layer between TiO₂ core and silica shell. The surfaces of SiO₂-void-TiO₂ were modified by partial alkylsilylation of n-octadecyltrimethoxysilane to render the surface with amphiphilicity to prepare w/o-SiO₂-void-TiO₂. Both the SiO₂-void-TiO₂ and the w/o-SiO₂-void-TiO₂ were characterized using XRD, TEM, BET, FT-IR and UV-Vis DRS techniques. Results demonstrated that the as-prepared SiO₂-void-TiO₂ and w/o-SiO₂-void-TiO₂ showed core(TiO₂)-hollow-shell(silica) microspherical structure. The w/o-SiO₂-void-TiO₂ sample was amphiphilic core-shell microspheres and it could be easily located at the boundary of the dual-phase mixture. Under UV light irradiation for 180 min, the methylene blue degradation rate of SiO₂-void-TiO₂ and w/o-SiO₂-void-TiO₂ photocatalysis reached 89.4% and 83.8%, respectively. Based on these results, possible mechanisms of SiO₂-void-TiO₂ core-hollow-shell microspheres formation and partial modification were discussed.