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 (TiO2) monoliths were prepared using 1-butyl-3-methylimidazolium tetrafluoroborate (BMIM+BF4-) 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'+BF4-. Mesoporous structures of the product with a surface area of ca. 260 m(2) g(-1) were retained upon calcining to 450 degrees C, showing excellent thermal stability. Furthermore, the products revealed higher photocatalytic activities than that of the commercially available TiO2, Degussa P25. Compared with the rutile TiO2 crystal of microporous structure prepared without RTIL, it was thought that BMIM+BF4- acted as a structure-directing agent and enhanced the polycondensation and crystallization rate, resulting in the facile formation of anatase crystal. The nanostructure TiO2 has promising applications in photocatalysis, solar energy conversion, sensor, mesoporous membranes, etc.