Heterogeneous photocatalysis has been reported to be effective for the degradation of a wide range of organic pollutants and the inactivation of pathogens in water. The use of nanostructured materials is one approach to improving photocatalytic efficiency. Titanate nanotubes were prepared by a hydrothermal synthesis and annealing yielded titania nanotubes, nanorods and crystals. These materials were characterized using XRD, XPS, BET and TEM. The photocatalytic activities were studied using phenol and formic acid as model pollutants. The as prepared titanate nanotubes had a very high specific surface area (401 m2g-1). Annealing at 400oC gave anatase TiO2, however, the tubular structure collapsed to rods leaving only 30% nanotubes. The sample containing 30% nanotubes was found to be 3.4 times more active than Degussa P25 for the photocatalytic oxidation of formic acid. Annealing at temperatures higher than 400oC caused a reduction in photocatalytic activity for the oxidation of formic acid. This correlated to a decrease in the specific surface area of the samples. In the case of phenol, the rate of photocatalytic oxidation increased with increasing annealing temperature, with the nanocrystals obtained at 700oC showing the highest rate, yet still lower than that observed for P25.
|Journal||Journal of Advanced Oxidation Technologies|
|Publication status||Published - 21 Feb 2011|
Wadhwa, S., Hamilton, JWJ., Dunlop, PSM., Dickinson, C., & Byrne, JA. (2011). Effect of post-annealing on the photocatalytic activity of hydrothermally synthesised titania nanotubes. Journal of Advanced Oxidation Technologies, 14(1), 147-157.