复合空心TiO2@SiO2纳米微球光催化性能研究

通过聚乙烯吡咯烷酮(PVP)功能化的聚苯乙烯(PS)粒子在SiO2包覆的同时被乙醇/氨水介质溶解,得到了单分散空心SiO2纳米微球,经溶胶-凝胶法与纳米TiO2复合制备得到了TiO2@SiO2纳米球.利用透射电子显微镜(TEM)和X射线衍射仪(XRD)对制备的TiO2@SiO2纳米球进行了物理特性及光化学性质的初步表征,探讨了SiO2纳米微球的复合对TiO2粒径大小、比表面积、形貌、晶型转变以及光催化活性的影响.在可见光照射下,利用有机染料罗丹明B(Rhodamine B,RhB)的光催化降解为探针反应,研究了TiO2@SiO2纳米球的光催化活性及适应的pH范围.结果表明,SiO2纳米球的复合能明显提高光催化剂的比表面积及其对RhB的吸附量.同时能明显提高TiO2在可见光下的光催化活性,可见光下照射120min后RhB完全褪色,同时16h后的矿化率达到60%.TiO2@SiO2纳米球在pH 3～9范围内均表现出较高的催化性能.

Preparationof TiO2@SiO2 Nanoparticles and Photocatalytic Degradation of Poisonous Organic Pollutants

The monodispersed and hollow nanospheres SiO2 were prepared by dissolving polystyrene （PS） functionalized by polyvinylpyrrolidone （PVP） using ethanol/ammonia. TiO2 @ SiO2 nanospheres were ob- tained by sol-gel method when composited SiO2 with TiO2. Physical properties and photochemical properties of TiO2@SiO2 prepared were studied by electron microscopy （TEM） and X-ray diffraction （XRD） to probe the effect of SiO2 on the specific surface area, particle size, morphology, crystal transformation and photocatalytic activity of TiO2@SiO2. The degradation of rhodamine B （RhB） under visible light irradiation was used as a probe reaction to analyze the photocatalytic activity of TiO2 @SiO2 and the range of adaptable pH. The results show that the SiO2 increases the specific surface area, adsorption capacity and photocatalytic activity of TiOz @SiO2 under visible light. RhB is discolored completely after 20 minutes and the mineralization rate reaches 60; after 16 h. At pH 3--9; the photocatalytic activity of TiO2@SiO2 is high.