介孔TiO2/WO3空心球的制备及其可见光光催化性能

以硫酸氧钛和偏钨酸铵为前驱体, 以柠檬酸作为络合剂, 采用喷雾干燥-高温煅烧两步法制备了介孔TiO₂/WO₃空心球复合材料。利用SEM、TEM、BET、XRD、UV-Vis DRS等手段对样品的形貌、微结构、比表面积、晶相组成和光学性能进行了表征和分析, 以亚甲基蓝为模拟降解物考察其光催化性能。结果表明: 复合材料为介孔空心球状结构, 球体分散好, 直径主要分布在1 μm左右; 球壁由纳米颗粒和空隙构成, 随着煅烧温度的升高, 颗粒粒径不断增大, 空隙孔径不断增大。性能研究结果表明, TiO₂与WO₃复合后, 样品对光的吸收范围扩展到了可见光区域, 这有利于提高太阳光的利用率; 当前驱体中WO₃含量为3mol%, 样品的煅烧温度为500℃时, 复合材料具有最好的光催化性能: 对亚甲基蓝降解率可达99.1%, 而P25的降解率仅为29.5%。

Preparation and Visible-light Photocatalytic Performance of Mesoporous Hollow TiO2/WO3 Spheres

By using titanyl sulfate and ammonia metatungstate (AMT) as precursors and citric acid as a complexing agent, mesoporous hollow spheres of TiO₂/WO₃ composites were prepared via a two-step approach, which included a spray-drying process followed by a high-temperature calcination course. The morphologies, microstructures, surface area, crystal phase, and optical properties of the composites were characterized by SEM, TEM, BET, XRD and UV-Vis DRS. The results showed that the TiO₂/WO₃ composites were well-dispersed mesoporous hollow spheres with diameters around 1 μm, of which the wall consisted of nanoparticles and mesopores. What’s more, nanoparticles and mesopores increased with the calcination temperature. UV-Vis DRS analysis showed that the absorption spectra of TiO₂/WO₃ composites could extend from ultraviolet region to visible region, which was helpful to improve the utilization efficiency of sunlight. In addition, photocatalytic activities of the prepared samples were investigated by photo-degradation of methylene blue (MB). It’s found that the composite containing 3% molar ratio of WO₃ with calcination temperature of 500^oC showed the best photocatalytic activity. The degradation efficiency of MB with this composite could reach 99.1%, much higher than that of P25, which was only 29.5% under the same conditions.