Preparation And Modification Of Titania Nanotube And Its Photocatalytic Performance

In this essay, TiO2 nanotubes (TNT) with different morphology, structure and surface area were prepared by hydrothermal treatment and subsequent calcined at 300℃,400℃, 500℃, respectively. Ag-doped TiO2 nanotubes (Ag/TNT) and Au-doped TiO2 nanotubes (Au/TNT) were prepared by photo-reduction method. The morphology, structure, area surface and the valence of Ag and Au of TNT, Ag/TNT and Au/TNT were characterized by TEM, XRD, BET and XPS. Take the nitrobenzene as the target pollution, we investigate the effects of calcination temperature, pH, and the amount of catalyst for the photocatalytic performance of TNT; studying the effects of calcination temperature of TNT, the amount of Ag or Au, pH and the reusage of photocatalytic on the photocatalytic activities of Ag/TNT and Au/TNT. The main conclusions are summarized as follows:Calcination temperature has an important impact on the morphology, crystalline and photocatalytic performance of the TiO2 nanotubes. With the increasing of the calcination temperature, the BET surface area decreased, the content of anatase increased, tubular structures destroyed (TNT had no obvious damage when the calcination temperature was below 400℃) and the TNT calcined at 400℃owned the best photocatalytic activity.Ag and Au were separately deposited on the TNT by photo-reduction method, TEM, XRD, BET, XPS characterization results showed that in a certain range of deposition, the crystal structure and tubular structures had no significant impact after deposited of Ag and Au, and the titania was still ordered nanotube structure, the BET surface area decreased after deposited Ag or Au, XPS characterization showed that the Ag/Au nanoparticles on the surface of Ag/TNT and Au/TNT were Ag(0) or Au(0).The Ag/TNT and Au/TNT had a better photocatalytic activity than TNT; TNT calcined at 400℃, doped with 0.5 wt% Ag or 0.1 wt% Au showed the highest photocatalytic activity. When the solution was alkaline, the photocatalytic activity of Ag/TNT and Au/TNT were better; Ag/TNT and Au/TNT retained high photocatalytic activities after been reused for four times; TOC and HPLC analysis concluded that in the process of Au/TNT photocatalytic degradation of nitrobenzene, some of the nitrobenzene was converted into aniline and degraded further.