FABRICATION AND PHOTOCATALYTIC ACTIVITY OF TiO2 NANOTUBES BY HYDROTHERMAL TREATMENT

TiO2 nanotubes were prepared by hydrothermal method using P25 as raw material. The effect of hydrothermal duration and calcination temperature on the crystal structure and morphology of intermediate product and TiO2 was investigated by XRD, SEM and TEM. The photocatalytic activity of TiO2 was evaluated by the degradation of methylene blue. The result revealed the formation process of nanotube and indicated that the photocatalytic activity of TiO2 nanotubes strongly depended on the calcination temperature. The crystallinity of nano-TiO2 was gradually improved with the increasing calcination temperature up to 750 oC resulting in the increase of degradation rate of methylene blue. With further increase in calcination temperature, anatase TiO2 began to transform into rutile phase and the nanotubes completely transformed to particles, leading to the decrease of photocatalytic activity. It was found that TiO2 annealed at 750 oC showed the highest degradation rate, resulting from the excellent crystallinity of anatase phase and nanorod structure.