摘要
利用溶胶-凝胶法制备掺钒纳米TiO_2,研究其在可见光条件下对SO2气体的催化氧化效果。采用烟气分析仪和碘量法测定SO2的浓度。利用XRD、BET、TEM、SEM、XPS、UV对掺钒TiO_2进行表征;研究焙烧温度、时间以及掺杂量等制备条件,对TiO_2脱除SO2的影响效果,探讨光催化氧化SO2的机理。结果表明:有O2条件下,在焙烧温度为700℃,时间为3 h,掺钒量物质的量含量为1.0%时,制备的TiO_2光催化氧化性能最好,SO2的脱除效率大于97%,氧化产物为SO3;光照和催化剂是SO2氧化的必要条件;光氧化效率随初始浓度的增大而增大,光催化反应符合一级反应动力学,且包括吸附和表面反应两部分,其中吸附为速控步骤;钒的掺杂使TiO_2产生红移,增强可见光催化活性,提高SO2气体的氧化效率。
The V-doped nanometer titanium dioxide was prepared via a sol-gel method, and its effect on photo-catalytic activity toward SO2 was studied. The variation of SO2 concentration was measured using a flue gas analyzer and an iodine titration method. Meanwhile the V-doped nanometer titanium dioxide is characterized by XRD, BET, TEM, SEM, XPS and UV. The photo-catalytic oxidation efficiencies of SO2 were determined under the different conditions such as the calcining time, calcining temperature and doping ratio. With the addition of O2, the optimum conditions are found as follows： calcining temperature at 700 ℃ , the calcining time 3 h, and the doping ratio of vanadium at 1.0% （mole fraction）. Under such conditions, the removal efficiency of SO： can reach 97% or higher; and the resulting product is SO3. The exposure to visible light and the presence of catalyst are necessary for the photo-catalytic reactions of SO2. The photo-catalytic efficiency increases with the increase of SO2 initial concentration. The photo-catalytic reaction, consisting of adsorption （rate determining step） and surface reaction, is first order in SO2 concentration. The red-shift is observed due to V-doping. Thus the V-doped TiO2 can be irradiated by the visible light and take part in photo-induced the oxidization. Therefore the SO2 photo-catalytic oxidation is enhanced.
出处
《太阳能学报》
EI
CAS
CSCD
北大核心
2015年第11期2690-2697,共8页
Acta Energiae Solaris Sinica
基金
河北省教育厅指导性计划(Z2012022)
关键词
掺钒二氧化钛
可见光催化氧化
SO2
动力学
机理
V-doped TiO2
visible-light photo-catalytic oxidation
sulfer dioxide
kinetics
mechanism
