表面疏水性纳米TiO_2颗粒的制备及光催化性能

The synthesis of hydrophobic nano-TiO_2 powder and its photocatalytic property

在70℃水解钛酸四丁酯(TBOT)时加入十二烷基硫酸钠(SDS),无需热处理就能得到准球形锐钛矿结构的纳米TiO2.这种TiO2粉具有强疏水性,漂浮于水溶液的表面,可通过过滤手段与溶液分离.应用透射电子显微镜和X射线衍射仪对TiO2粉进行了形貌观察和晶体结构的测定.研究了反应体系pH值的变化对TiO2粉结构的影响.FT-IR光谱证明在酸性条件下SDS分子吸附于TiO2颗粒的表面.颗粒尺寸增大引起Raman峰、紫外吸收峰的红移,表现出量子尺寸效应.在对罗丹明B的光催化降解反应中,表面吸附SDS的TiO2粉显示出很强的光催化活性,在50 min内催化降解了100%罗丹明B.

Sodium dodecylsulfate (SDS) was used to control the hydrolysis of tetrabutyl titanate (TBOT) and modify the surface of TiO2 particles. Hydrophobic anatase-TiO2 particles shaped in pseudo-spherical were directly obtained without heat treatment. The TiO2 particles have distinct hydrophobic property, which can float on the surface of aqueous solution and are more easily separated from aqueous solution. The morphology, structure and optic characters of these TiO2 particles were confirmed by means of TEM, XRD, FT-IR, Raman and UV-Vis spectrum. The effect of pH values on the structure of hydrolytic products was also investigated. The FT-IR spectrum showed there were organic molecules on the surface of TiO2 particles synthesized at acid condition. The quantum size effect was observed as the Raman and UV-Vis spectra shifting toward long-wave with increasing the particle size. In the photo-catalytic reaction, the Rhodanmine B was degraded 100% in 50 min by the TiO2 modified by SDS.