溶胶-凝胶法制备S掺杂TiO2纳米粉体的光催化性能

Photocatalytic Properties of S-doped TiO_2 Nano-powders Prepared by Sol-gel Method

本研究采用溶胶-凝胶法制备了S掺杂TiO_2纳米粉体。采用X射线衍射(XRD)、热重差热(TG-DTA)、傅里叶变换红外光谱(FT-IR)、透射电子显微镜(TEM)、能量弥散X射线能谱(EDS)及X射线光电子能谱(XPS)等测试手段对其进行了表征,以亚甲基蓝为模拟污染物,评价了不同热处理条件下的粉体在可见光下的光催化活性。结果表明:S掺杂对TiO_2由锐钛矿型向金红石型的转变有抑制作用,但对其微观形貌没有影响;部分S进入TiO_2晶格间隙形成Ti-O-S键,部分S以SO_4^(2-)的形式吸附于TiO_2表面,S含量约为0.3at%;S掺杂TiO_2纳米粉体具有较高的可见光催化活性,当硫酸钠加入量为10%,550℃煅烧1 h的S/TiO_2样品的光催化活性最佳,在可见光下对亚甲基蓝的2 h降解率由未掺杂的74.12%提高至86.15%。

S-doped TiO2nano-powders were prepared by a sol-gel method. The powders were characterized by XRD,TG-DTA,FT-IR,TEM,EDS and XPS. The photocatalytic activities of the powders prepared under different heat treatment conditions were evaluated according to their photodegradation behavior to methylene blue in visible light. The results indicated that S doping had no obvious effect on the surface morphology of TiO2,but inhibited the growth of TiO2grains and the transformation of TiO2from anatase to rutile. Parts of S was incorporated into the TiO2lattice interstitial sites to form Ti-O-S bond,parts adsorbed on the surface of TiO2as SO4^2-,the sulphur content was about 0. 3 at%. In addition,the S-doped TiO2powders had a good visible photocatalytic activity. The S-doped TiO2calcined at 550 ℃ with an optimal photocatalytic activity were fabricated with the Na2 SO4 concentration of 0. 6 wt%. The photocatalytic degradation rate of MB in 2 h increased from 74. 12% for TiO2to 86. 15% for S/TiO2.