复合催化剂NdPW12O40/TiO2的制备、表征及光催化性能

 采用溶胶-凝胶法制备了NdPW12O40/TiO2复合催化剂,并用热重-差热分析、红外光谱、紫外-可见漫反射光谱、荧光发射光谱、扫描电镜和X射线衍射对催化剂进行了表征. 在紫外光照射下,以有机污染物丙酮和甲醇的气相光催化消除为模型反应,考察了催化剂的光催化活性. 结果表明, NdPW12O40的掺杂使TiO2纳米晶粒细化(粒径为11～14 nm), 表面积增大,同时有效抑制了TiO2粒子的团聚. 0.1 g 1%NdPW12O40/TiO2光催化消除初始浓度为6.58 g/m3的丙酮,空时为2.4 s时消除率可达96.74%, 达到排放要求; 催化消除初始浓度为8.82 g/m3的甲醇,空时为2.0 s时消除率可达100%, 实现完全矿化. 与纯的TiO2相比,复合催化剂吸收光的能力增强,吸收带边向长波方向延伸了20 nm.

Preparation,Characterization,and Photocatalytic Performance of NdPW12O40/TiO2 Composite Catalyst

The NdPW_ 12 O_ 40 /TiO_2 composite catalyst was prepared by the sol-gel method and characterized by thermogravimetric-differential thermal analysis, infrared spectroscopy, ultraviolet-visible diffuse reflectance spectroscopy, fluorescence emission spectroscopy, scanning electron microscopy, and X-ray diffraction. The photocatalytic eliminations of acetone and methanol were used as model reactions to evaluate the photocatalytic activity of the composite catalyst under ultraviolet light irradiation. The results show that TiO_2 modified by NdPW_ 12 O_ 40 has small crystal size (11 to 14 nm) and large surface area, and the aggregation of TiO_2 particles is effectively inhibited. When the initial concentration of acetone is 6.58 g/m~3 and the space time is 2.4 s, the mineralization rate is 96.74% using 0.1 g of 1%NdPW_ 12 O_ 40 /TiO_2 as the catalyst, which conforms to the requirements of emission standards for air pollutants. Methanol can be mineralized completely when its initial concentration is 8.82 g/m~3 and the space time is 2.0 s. Compared with pure TiO_2, the light absorption ability of NdPW_ 12 O_ 40 /TiO_2 gets enhanced, and the absorption region extends to long wavelengths by 20 nm.