In this paper, TiO2 nanoparticles pure and doped with varying content of Ce were prepared by a sol-gel process using Ti(OC_4H_9)_4 as raw material and characterized by XRD, TEM, BET, XPS and PL spectra. We mainly investigated the effects of calcining temperature and Ce content on the properties and the photocatalytic activity for degrading phenol of the TiO2 nanoparticles. The relationships between PL spectra and photocatalytic activity as well as the mechanisms of Ce doping on TiO2 phase change were also discussed. The results show that Ce4+ did not enter into the crystal lattices of TiO2 and was uniformly dispersed into TiO2 as the form of CeO2 with small size, which possibly made Ce dopant have a great inhibition on TiO2 phase change; Ce dopant did not give rise to a new PL signal, but an appropriate content of Ce could make the intensity of PL spectra down, which was attributed to the ability of Ce + to easily capture the photoinduced electrons to form Ce3+; Ce doped TiO2 nanoparticles calcined at 600 t exhibited higher photocatalytic activity, indicating that 600 ℃ was an appropriate calcination temperature. The order of the photocatalytic activity of TiO2 samples doped with varying content of Ce is as follows: 3 mol% > 4 mol% > 2 mol% > 5 mol% > 1 mol% > 0 mol%, which is opposite to the order of their PL intensity, namely, the weaker the PL intensity, the higher the photocatalytic activity, demonstrating that there are certain relationships between PL spectra and photocatalytic activity. This could be explained by the fact that the dopant Ce4+ can readily capture the photoinduced elections, which not only makes the intensity of PL spectra down during the process of phololuniinescenoe but also improves the oxidation speed of organic pollutants during the process of pliotocatalytic reaction.

Key words: TITANIUM DIOXIDE, NANOPHASE MATERIALS, DOPE, CERIUM, PHOTOCATALYSIS, PHENOL, SOL-GEL PROCESS