WO3-TiO2复合空心球的制备及其光催化性能

以钛酸四正丁酯和偏钨酸铵为原料,采用水热-模板法制备复合WO3-TiO2光催化剂。利用X射线衍射(XRD)、扫描电子显微镜(SEM)、比表面积(BET)和紫外-可见漫反射(UV-Vis DRS)等手段对催化剂的结构和光学性能进行表征。结果表明:WO3-TiO2复合半导体中的TiO2为锐钛矿晶型,焙烧后的WO3-TiO2呈中空球形结构,粒径在320 nm左右,且粒径分布均匀,其比表面积和平均孔径分别为40.95 m2/g和16.91 nm,WO3-TiO2复合半导体的紫外-可见吸收边带较TiO2的红移约50 nm,并在400~500 nm处有吸收。光降解甲基橙(MO)实验显示:经过80 min光照后,WO3-TiO2复合半导体在紫外和可见光下对甲基橙的降解率分别为99.2%和81%,而TiO2的仅为64%和25%,且在紫外和可见光下WO3-TiO2复合半导体的表观速率常数分别是TiO2的3.2和4.9倍左右。

Preparation of composite WO3-TiO2 hollow spheres and its photocatalytic properties

Composite photocatalysts WO3-TiO2 hollow spheres were prepared by hydrothermal-template method using tetrabutylortitanate and ammonium metatungstate as raw materials.The structural and optical properties of WO3-TiO2 were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),BET analysis and ultraviolet-visible diffuse reflection spectroscopy(UV-Vis DRS).The results show that TiO2 in the WO3-TiO2 hollow spheres is in anatase phase,the calcination of these composite particles results in the fabrication of WO3-TiO2 hollow spheres,the diameter of the composite photocatalysts is about 320 nm with uniform particle size distribution.The specific surface area and average pore diameter of the hollow spheres are 40.95 m2/g and 16.91 nm,respectively.The main absorption edges of the WO3-TiO2 hollow spheres are red-shifted about 50 nm and there is an absorption in the wavelength region from 400 to 500 nm compared with that of the TiO2 hollow spheres.The photodegradation of methyl orange(MO) was used to evaluate the photocatalytic activity of the catalysts under UV and visible light irradiation.99.2% and 81% MO are degraded by WO3-TiO2 hollow spheres under UV and visible light within 80 min.Under the same conditions,only 64% and 25% MO can be photodegraded by TiO2.The apparent rate constant of WO3-TiO2 composite semiconductor material is significantly increased,which is 3.2 and 4.9 times as that of the TiO2 material under both UV and visible light irradiation,respectively.