S改性的纳米TiO_2的制备及其可见光催化性能研究

Preparation and Visible Light Photocatalytic Activity of S-Modified Nanomaterials TiO_2

以四氯化钛为钛源,硫溶胶为硫源,在室温下采用水解沉淀法制备了单质硫改性的纳米TiO2光催化剂.采用X-射线衍射(XRD)、透射电子显微镜(TEM)、X-射线光电子能谱(XPS)、紫外-可见(UV-Vis)漫反射光谱和N2吸附-脱附对样品进行了表征分析.以次甲基蓝(MB)溶液为模拟废水,对其可见光催化性能进行了评价,研究了不同热处理温度对光催化活性的影响.结果表明,硫掺杂有效地抑制了纳米TiO2在热处理过程中由锐钛矿向金红石的转变,在低温下热处理得到的样品为单质硫与TiO2的复合,而500℃以上热处理得到的样品为S4+的掺杂,S复合与掺杂的纳米TiO2光催化剂在可见光区有明显的吸收,400℃热处理所得样品具有最好的光催化性能.这种硫复合或掺杂的纳米TiO2的催化降解性能显著高于相同方法制备的纯TiO2.催化剂经6次重复使用其光催化活性基本保持不变.

An accessible, template-free process to fabricate S-modified TiO2 nanocrystallites was developed by using TiC14 and sulphur iodine hydrosol as precursor according to hydrolysis precipitation method. The samples were characterized by XRD, TEM, XPS, UV-Vis-DRS and BET, pies was evaluated by degradation of methylene blue （MB） as respectively. The photocatalytic activity of samtarget pollutant. The relation of the heat treat- ment temperatures and the photocatalysis activity of the samples were also studied. The results showed that sul- fur doping restrained effectively the phase transformation from anatase to rutile and the nanocrystallites exhibi- ted stronger absorption in visible light region. S element composite with TiO2 when the heat treatment is lower than 400~C and S4＋-doped with TiO2 when the heat treatment reach to 500~C were obtained. The sample that thermal treatment at 400℃ manifested the highest photocatalytic activity for photodecomposition of MB solution compared with thermal treatment at other temperatures and the uncomposite TiO2 under the irradiation of visi- ble-light. Little difference of the activity was observed between the samples used for 6 times.