锐钛矿型纳米TiO_2水溶胶的低温制备与光催化性能

LOW TEMPERATURE PREPARATION OF ANATASE NANO-TiO_2 HYDROSOL AND ITS PHOTOCATALYTIC PROPERTIES

以TiCl4、氨水、H2O2等为原料,不加表面活性剂,仅对工艺过程进行控制,通过水解、沉淀、胶溶、络合、80℃回流等步骤制备了纳米TiO2水溶胶。采用X射线衍射、扫描电镜、紫外-可见光吸收光谱等对制备的水溶胶进行表征。结果表明:制备的水溶胶中含有锐钛矿型针状纳米TiO2晶粒,晶粒沿c轴择优生长,粒径尺寸小于10nm,形貌一致、分散性好;水溶胶的吸收边红移至470nm。以10mg/L甲基橙溶液为降解对象,在紫外灯下照射1h考察了TiO2水溶胶的光催化性能。结果显示:80℃回流10h的水溶胶光催化性能较好,降解率达到87.7%;随回流时间的延长,水溶胶的光催化活性提高。

Nano-TiO2 hydrosol was synthesized using titanium tetrachloride （TiCl4）, ammonia （NH3·H2O） and peroxide （H2O2） as raw materials. Without surfactant, and only by controlling the technological conditions, the TiO2 hydrosol was prepared by hydrolyzing, precipitating, peptizing, complexing and refluxing at 80℃. The samples were characterized by X-ray diffraction, transmission electron microscopy and ultraviolet-visible spectroscopy. The results show that the TiO2 hydrosol contains acicular and anatase nano-TiO2 crystal grains with homogeneous morphology and good dispersibility; these grains grow along the c-axis and their diameters are smaller than 10 nm. The absorption edge wavelength of the TiO2 hydrosol shifts to 470 urn. The photocatalytic activities of the TiO2 hydrosol were determined by degradation of 10 mg/L methyl orange under ultraviolet lamp irradiation for 1 h. The TiO2 hydrosol refluxed at 80 ℃ for 10 h has the best photocatalytic activity, and its degradation rate reaches 87.7%. The photocatalytic activity of TiO2 hydrosol increases With the prolonging of refluxing time.