Synthesis, characterization and photocatalytic activity of 1D TiO2 nanostructures

Nanowire/nanorod TiO 2 structures of approximately 8 nm in diameter and around 1,000 nm long were synthesized by alkaline hydrothermal treatment of two different TiO 2 nanopowders. The first precursor was TiO 2 obtained by the sol-gel process (SG-TiO 2 ); the second was the well-known commercial TiO 2 P-25 (P25-TiO 2 ). Anatase-like 1D TiO 2 nanostructures were obtained in both cases. The one-dimensional (1D) nanostructures synthesized from SG-TiO 2 powders turned into rod-like nanostructures after annealing at 400 °C for 2 h. Conversely, the nanostructures synthesized from P25-TiO 2 preserved the tubular structure after annealing, displaying a higher Brunauer–Emmett–Teller surface area than the first system (279 and 97 m 2 /g, respectively). Despite the higher surface area shown by the 1D nanostructures, in both cases the photocatalytic activity was lower than for the P25-TiO 2 powder. However, the rod-like nanostructures obtained from SG-TiO 2 displayed slightly higher efficiency than the sol-gel prepared powders. The lower photocatalytic activity of the nanostructures with respect to P-25 can be associated with the lower crystallinity of 1D TiO 2 in both materials.