Department of Chemical and Biomedical Engineering, University of South Florida, Tampa, FL 33620, USA.
Nanotechnology. 2012 Jul 27;23(29):294012. doi: 10.1088/0957-4484/23/29/294012. Epub 2012 Jun 28.
Nanostructured highly porous TiO(2)/WO(3)/Fe(3+) aerogel composite photocatalysts are prepared, characterized and tested for model photocatalytic reactions. The catalyst structure is tailored to capture environmental pollutants and enable their decomposition in situ under both ultraviolet (UV) and visible light through oxidation to smaller benign molecules. A novel and green method is utilized to prepare the unique surfactant-templated aerogel composite photocatalyst that has a highly accessible porous nanostructure with high surface area and tailored pore size distribution. The sol-gel process is combined with supercritical extraction and drying. Supercritical drying with heat treatment results in titanium dioxide with anatase crystal form. Templates used further enable retention and tuning of the nanopore structure and surface properties. The synthesized catalysts were characterized using SEM, FIB, XRD and porosimetry prior to post-evaluation in model reactions. The bandgap of the catalyst particles was also determined using diffuse reflectance. The resulting aerogel TiO(2)/WO(3)/Fe(3+) has similar photocatalytic capability compared to highly optimized commercial Degussa P25 under UV exposure and offers much superior photocatalytic capability under visible light exposure. The model reaction utilized employed methylene blue (MB) photooxidation under visible and UV light.
制备、表征和测试了用于模型光催化反应的纳米结构高多孔 TiO(2)/WO(3)/Fe(3+)气凝胶复合光催化剂。通过氧化将催化剂结构调整为捕获环境污染物并使其在紫外 (UV) 和可见光下原位分解为更小的良性分子。利用一种新颖的绿色方法制备了独特的表面活性剂模板气凝胶复合光催化剂，该催化剂具有高比表面积和可调孔径分布的高可及性多孔纳米结构。溶胶-凝胶工艺与超临界萃取和干燥相结合。热处理后的超临界干燥导致锐钛矿晶型的二氧化钛。模板进一步允许保留和调整纳米孔结构和表面性质。在模型反应中进行后评估之前，使用 SEM、FIB、XRD 和孔隙率法对合成的催化剂进行了表征。还使用漫反射确定了催化剂颗粒的带隙。所得气凝胶 TiO(2)/WO(3)/Fe(3+)在 UV 照射下与高度优化的商业 Degussa P25 具有相似的光催化能力，并在可见光照射下提供了优异得多的光催化能力。使用的模型反应是在可见光和紫外光下进行亚甲基蓝 (MB) 的光氧化。
