| Abstract: | Mixed-phase TiO_2 photocatalysts with small particle size of anatase and rutile(~5 nm) have been successfully synthesized using hydrothermal method. The effects of curing temperature and curing time before the hydrothermal treatment on the crystalline phase, the phase composition, and the particle size of TiO_2 were investigated by the X-ray diffraction spectroscopy(XRD) and the transmission electron microscopy(TEM), respectively. It was found that the anatase and rutile phase contents in the TiO_2 particles were successfully controlled by simply adjusting the curing temperature and the curing time. More importantly, the particle size of both anatase and rutile is small in the mixed-phase TiO_2 particles. The photocatalytic activity of TiO_2 was evaluated by the degradation of Rhodamine B(Rh B) in aqueous solution. The Ti O2 with phase junction formed by anatase and rutile exhibited higher separation rate between the photo-induced electrons and holes, which was confirmed by the surface photovoltage(SPV) spectra, and at the same time exhibited the higher photocatalytic degradation on Rh B than pure anatase-phase TiO_2. Moreover, it was found that TiO_2 with 83% of anatase and 17% of rutile showed a highest photocatalytic activity among the mixed-phase TiO_2 samples. |
