以P123作为模板剂,采用溶胶-凝胶法合成介孔SO42-/W-TiO2@SiO2(WSTS)可见光响应光催化剂。以甲基橙为模型物,考察其在可见光及紫外光区的光催化活性。采用X射线衍射(XRD)、环境扫描电子显微镜(SEM)、高分辨透射电子显微镜(HRTEM)、X 射线光电子能谱(XPS)、低温氮物理吸附(BET)、紫外-可见漫反射光谱(UV-Vis)、傅里叶变换红外光谱(FTIR)、热重分析(TG)和荧光光谱(PL)对样品的结构及性能进行表征。结果表明:W掺杂不但可以提高样品的比表面积、孔容,而且可以抑制晶型从锐钛矿向金红石转变。与光催化剂P25及未掺杂的样品相比,光催化活性明显提高。且W的最佳掺杂量为n(W)/n(Ti)=0.0025,其在可见光(λ>400 nm)和紫外光区辐照40 h和60 min后,甲基橙的脱色率分别是91.7%和98.9%。
The mesoporous SO42-/W-TiO2@SiO2 visible light photocatalysts were synthesized by sol-gel method using P123 as template. The photocatalytic activity of the prepared mesoporous SO42-/W-TiO2@SiO2(WSTS) for methyl orange was investigated under visible and UV light irradiation, respectively. The textural properties and structure of samples were characterized by X-ray diffraction (XRD), environmental scanning electron microscope (SEM), high-resolution transmission electron micro-scope (HRTEM), X-ray photoelectron spectroscopy (XPS), N2 adsorption-desorption measurements (BET), Fourier transform infrared spectroscopy (FTIR), UV-Vis diffuse reflectance spectroscopy, thermogravimetric analysis (TGA) and photoluminescence spectra (PL). The results show that the W doping not only increases the surface area and pore volume of sulfated mesoporous TiO2@SiO2, but also inhibits the phase transition from anatase to rutile. The photo-degradation results reveal that W doping can greatly improve the photocatalytic activity of sulfated TiO2@SiO2 with mesostructure, which is higher than that of undoped samples and the commercially available Degussa P25 titanium dioxide by degradation of methyl orange (MO) aqueous solutions. The optimal W doping is n(W)/n(Ti)=0.002 5 (mole fraction), the alloy expresses higher photocatalytic activity, the discoloration rates are 91.7%and 98.9%under visible light (λ>400 nm) for 40 h and UV light for 60 min, respectively.