Photocatalytic Activity of Hierarchical Flower-Like TiO2 Superstructures with Dominant {001} Facets

The fabrication of well defined hierarchical structures of anatase TiO2 with a high percentage of reactive facets is of great importance and challenging. Hierarchically flower-like TiO2 superstructures (HFTS) self-assembled from anatase TiO2 nanosheets with exposed {001} facets (up to 87%) were synthesized by a simple alcohothermal strategy in a HF-H2O-C2H5OH mixed solution using titanate nanotubes as precursor. The samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and N2 adsorption-desorption isotherms. The photocatalytic activity was evaluated by the photocatalytic oxidation decomposition of acetone in air and methyl orange in aqueous solution under UV illumination. The photocatalytic activity of HFTS was much higher than that of commercial Degussa P25 and tabular-shaped anatase TiO2 obtained using pure water as the synthesis medium. The enhancement in photocatalytic activity was related to several factors, including the hierarchically porous structure, exposed {001} facets, and increased light harvesting ability. The HFTS was also of interest for use in solar cells, photocatalytic H2 production, optoelectronic devices, sensors and catalysis.

摘要： 以钛酸盐纳米管为前驱体, 在 HF-H2O-C2H5OH 的混合溶液中, 采用一种简单的醇热方法合成了具有 87% 暴露{001}面的 TiO2 纳米片自组装形成的分等级花状 TiO2 超结构. 运用 X 射线衍射、扫描电镜、透射电镜和 N2 吸附-脱附等方法对样品进行了表征, 并在紫外光照射下于空气和溶液中分别考察了其光催化降解丙酮和甲基橙反应活性. 结果表明, 这种分等级花状结构 TiO2 的光催化活性比商业 P25 和在纯水中制备得到的片状锐钛矿 TiO2 的光活性高得多. 这主要是由于该样品具有分等级的多孔结构, 暴露的{001}晶面和增强的光吸收能力. 这种分等级花状 TiO2 超结构在太阳能电池、光催化产氢、光电子器件、传感器和催化方面也具有巨大的应用前景.

Hierarchical flower-like TiO2 superstructures with numerous exposed {001} facets were synthesized by a simple alcohothermal route. They showed enhanced photoactivity for decomposition of acetone in air.Figure optionsDownload as PowerPoint slide