SYNTHESIS AND MICROSTRUCTURE OF A NOVEL TiO2 AEROGEL-TiO2 NANOWIRE COMPOSITE

TiO2 aerogel-10mol% TiO2 nanowire composite was prepared by a sol-gel technique with the addition of TiO2 nanowires to TiO2 sol, followed by supercritical drying in CO2. TiO2 nanowires (anatase with minor rutile phases) as dispersoid were prepared by a hydrothermal process followed by calcination in air at 600 degrees C. The TiO2 nanowires were dispersed in a 2-propanol/H2O/HNO3 solution, and the mixture was added drop by drop to a tetrabutyl orthotitanate [i.e. Ti (IV) n-butoxide] solution in 2-propanol. After gelation, the TiO2 alcogel TiO2 nanowire composite was dried in supercritical CO2 to obtain the final, TiO2 aerogel-TiO2 nanowire composite. TEM analysis revealed that a unique "nanowire network" structure was formed within the mesoporous aerogel matrix. The aerogel-TiO2 nanowire composite had a relatively large surface area 427m(2)/g, with mesopores similar to 16 nm in diameter and a pore of volume of 1.63 cm(3)/g.