Synthesis and microstructure of a novel TiO2 aerogel-TiO2 nanowire composite

TiO 2 aerogel–10 mol% TiO 2 nanowire composite was prepared by a sol–gel technique with the addition of TiO 2 nanowires to TiO 2 sol, followed by supercritical drying in CO 2. TiO 2 nanowires (anatase with minor rutile phases) as dispersoid were prepared by a hydrothermal process followed by calcination in air at 600°C. The TiO 2 nanowires were dispersed in a 2-propanol/ H 2 O / HNO 3 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 TiO 2 alcogel– TiO 2 nanowire composite was dried in supercritical CO 2 to obtain the final, TiO 2 aerogel– TiO 2 nanowire composite. TEM analysis revealed that a unique "nanowire network" structure was formed within the mesoporous aerogel matrix. The aerogel– TiO 2 nanowire composite had a relatively large surface area 427 m2/g, with mesopores ~ 16 nm in diameter and a pore of volume of 1.63 cm3/g.