核-壳式纳米SnO_2/TiO_2光催化剂的制备和性能

Preparation and Photocatalytic Properties of Nanometer SnO_2/TiO_2 of Nucleus-Shell Structure

以纳米SnO2 ·nH2 O胶体粒子为基质 ,采用活性层包覆法制备了纳米SnO2 /TiO2 复合光催化剂 ,并用IR ,TEM ,XPS和XRD等手段进行了表征 .采用敌敌畏的光催化降解反应对所制催化剂的活性进行了评价 .结果表明 ,SnO2 /TiO2 为核 壳结构 ,粒径约为 12nm .SnO2 /TiO2 的光催化活性受TiO2 含量及SnO2 ·nH2 O乙醇溶液含水量的影响 .最佳条件为SnO2 /TiO2中TiO2 含量为 5 6 4 5 % ,SnO2 ·nH2 O乙醇溶液含水量为 2 0 % .所制SnO2 /TiO2 光催化活性比纯TiO2 显著提高 ,且光催化活性稳定 ,可重复使用 .

Photocatalysts play an important role in environmental protection because of their potential application to photocatalytic degradation of organic contaminants in polluted wastewater. Using SnCl 4·5H 2O, ammonia spirit and C 2H 5OH as precursor, the hydrated collosol particles of SnO 2·nH 2O were prepared by precipitation, filtration, cleanse and reflux. Using Ti(OBu) 4 as coating compound, the composite SnO 2/TiO 2 coated particles were prepared by hydrolysis cross-link of TiO 2 on active surface of SnO 2·nH 2O, filtration, drying and calcination at 680 ℃ for 5 h. The morphology and structure of SnO 2/TiO 2 were characterized by IR, TEM, XPS and XRD methods. The result indicated that SnO 2/TiO 2 is of nucleus-shell structure, it is composite with anatase TiO 2 and rutile SnO 2, the particle diameter is 12 nm approximately, and its specific surface area is 72.27 m 2/g. The effect of preparation conditions of SnO 2/TiO 2 on its photocatalytic degradation activity for dichlorvos was investigated. When the content of TiO 2 in SnO 2/TiO 2 is 56.45% and the content of water in SnO 2 alcohol solution is 20%, SnO 2/TiO 2 reached the highest photocatalytic activity. SnO 2/TiO 2 showed higher activity than TiO 2 and can be reused for many times.