蒸汽相水解法制备磁性光催化剂Fe_3O_4/SiO_2/TiO_2及其光催化性能

采用蒸汽相水解法,以Fe3O4纳米磁性颗粒为磁核,在其表面包覆一层SiO2来阻止光腐蚀,然后将锐钛矿相纳米氧化钛沉积在Fe3O4/SiO2颗粒表面,从而制得核壳结构的Fe3O4/SiO2/TiO2磁性复合光催化材料。用X射线粉末衍射仪(XRD)、场发射扫描电镜(FE-SEM)、高分辨率透射电子显微镜(HR-TEM)、探针式震动磁强计等手段对所制备的产物的结构、形貌、磁强度性能进行表征。以300W汞灯为光源,用亚甲基蓝和酸性红模拟污水中的有机染料来评价复合光催化剂的性能。结果表明,磁性纳米微球中TiO2的含量越大,其光催化性能越好,含TiO2质量分数50%的F3O4/SiO2/TiO2磁性纳米微球可在180min内降解亚甲基蓝模拟染料废水,降解率达99%,在80min内降解酸性模拟染料废水,降解率达98%。

Preparation of magnetic photocatalyst Fe3O4/SiO2/TiO2 by vapor-phase hydrolysis method and its photocatalytic properties

Anatase TiO2 nanoparticles were deposited on the composite Fe3 O4/SiO2 ,where Fe3 O4 acted as the magnetic core and SiO2 acted as the protective coating against the photo corrosion of Fe3 O4 .Thus,the multi-layer composite of Fe3 O4/SiO2/TiO2 were obtained.The structure,morphology,magnetic characterization of the prepared product were characterized by the means of X-ray powder diffraction （XRD）,field emission scanning electron microscope （FE-SEM）,high resolution transmission electron microscopy （HR-TEM）and vibrating magnetometer probe.With 300 W mercury lamp as a light source,both methylene blue and acid red were used to simulate organic wastewater,the composite catalytic properties of visible light photocatalyst were evaluated.The results show that the greater the magnetic nanoparticles in TiO2 content,the better the photocatalytic properties. Fe3 O4/SiO2/TiO2 magnetic nanospheres containing TiO2 50% （mass fraction）can degrade 99% of methylene blue dye in wastewater for 180 min,while it degrade 98% of acid red G in the simulated wastewater under irradiation for 80 min.