Synthesis of TiO2 nanotubes and its photocatalytic activity for H-2 evolution

TiO2-derived nanotubes were prepared by hydrothermal treatment in 10 M NaOH(aq) by using commercially available TiO2 (Degussa P-25) as starting material. N-2-adsorption/desorption analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD) observations of the obtained product revealed the formation of titanate nanotube structure with its diameter of about 10-20nm. The effect of post-heat-treatment on the phase structure, morphology, specific surface area and photocatalytic activity was investigated. The TiO2 (B) nanotubes could be observed at post-heat-treatment of 300 degrees C. As post-heat-treatment was increased to 400 degrees C, the nanotubes began to transform into nanoparticles of anatase phase, producing a bi-crystalline mixture of TiO2 (B) nanotubes and anatase nanoparticles. Moreover, the particles changed into rutile phase through the post-heat-treatment at higher temperatures over 700 degrees C. The photocatalytic activity of prepared samples was evaluated with photocatalytic H-2 evolution. The results showed that the TiO2-derived nanotubes treated at appropriate temperature exhibited high H-2 evolution.