WO3/TiOF2-TiO2复合催化剂的制备及其光催化性能研究

采用水热法制备了具有太阳光光催化性能的WO₃/TiOF₂-TiO₂三元复合的系列光催化剂W∶Ti=X∶10（X=0.5、1、3、5）（其中X∶10为W与Ti元素的物质的量之比，下同）。为提升催化剂性能，在复合前用NaOH溶液对TiOF₂进行了改性处理，制备了W∶OH-Ti=X∶10（X=0.5、1、3、5）系列光催化剂。采用X射线衍射（XRD）、傅里叶变换红外光谱（FT-IR）、紫外可见漫反射光谱（UV-vis DRS）、扫描电子显微镜（SEM）、荧光光谱（PL）等手段对样品进行了表征。在模拟太阳光照射下，以盐酸四环素（TTCH）溶液为模拟废水，对催化剂性能进行了研究。结果表明，WO₃的加入使部分TiOF₂在高温下转变为TiO₂，W∶OH-Ti=1∶10复合光催化剂与TiOF₂相比，禁带宽度降低，可见光响应增强，电子-空穴的复合受到了抑制，并且TiOF₂经NaOH处理后，复合光催化剂增加了更多的羟基。模拟太阳光照射2.5h后，投加量为0.3g/L的W∶OH-Ti=1∶10催化剂对TTCH的降解率可达85%，说明所制备的三元复合光催化剂具有良好的催化效果。

Preparation and photocatalytic performance of a WO3/TiOF2-TiO2 composite photocatalyst

WO₃/TiOF₂-TiO₂ composite photocatalysts having different tungsten to titanium ratios W∶Ti=X∶10 (X=0.5, 1, 3, 5) with solar photocatalytic properties have been prepared by a hydrothermal method. In order to improve the activity of the catalysts, TiOF₂ was modified with NaOH solution before composite formation and a series of W∶OH-Ti=X∶10 (X=0.5, 1, 3, 5) photocatalysts prepared. The catalysts were characterized by X-ray diffraction (XRD), Fourier transform infrared spectrometry (FT-IR), UV-visible diffuse reflectance spectrometry (UV-vis), scanning electron microscopy (SEM), and photoluminescence (PL). Using simulated sunlight, the performances of the catalysts were investigated with tetracycline hydrochloride (TTCH) solution as simulated wastewater. The results show that the addition of WO₃ can convert some of the TiOF₂ into TiO₂ at high temperature. Compared with TiOF₂, the W∶OH-Ti=1∶10 composite photocatalyst has a reduced band gap, enhanced visible light response, and suppressed electron-hole recombination. After treatment of TiOF₂ with NaOH, more hydroxyl groups are incorporated in the composite photocatalyst. After exposure to simulated sunlight for 2.5 h, the W∶OH-Ti=1∶10 catalyst had a degradation efficiency of 85% for TTCH with an initial dosage of 0.3 g/L. The above results indicate that the ternary composite photocatalyst has good catalytic properties.