Preparation and Properties of Nanostructure Anatase TiO₂ Monoliths Using 1-Butyl-3-methylimidazolium Tetrafluoroborate Room-Temperature Ionic Liquids as Template Solvents

Nanostructure anatase titanium oxide (TiO 2 ) monoliths were prepared using 1-butyl-3-methylimidazolium tetrafluoroborate (BMIM + BF 4 - ) room-temperature ionic liquids (RTILs) as template solvents by a simple sol−gel method with a peptization process at ambient temperature. The as-prepared products exhibited wormlike pore structures and large surface areas, which ranged from ca. 118 to ca. 498 m 2 g -1 by adding various amounts of BMIM + BF 4 - . Mesoporous structures of the product with a surface area of ca. 260 m 2 g -1 were retained upon calcining to 450 °C, showing excellent thermal stability. Furthermore, the products revealed higher photocatalytic activities than that of the commercially available TiO 2, Degussa P25. Compared with the rutile TiO 2 crystal of microporous structure prepared without RTIL, it was thought that BMIM + BF 4 - acted as a structure-directing agent and enhanced the polycondensation and crystallization rate, resulting in the facile formation of anatase crystal. The nanostructure TiO 2 has promising applications in photocatalysis, solar energy conversion, sensor, mesoporous membranes, etc.