Abstract:The Nd-doped TiO₂ thin films with higher hydrophilic and photocatalytic activities were prepared on glass slides by an acid-catalyzed sol-gel method. The effects of Nd doping on crystalline phase, surface composition and optical property were investigated by means of techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), optical contact angle tester and UV-Vis spectroscopy. The results show that Nd doping obviously influences the hydrophilic and photocatalytic activities of TiO₂ thin films. Nd doping could cause the TiO₂ lattice distortion, inhibit phase transition from anatase to rutile, cause red shift of the absorption spectrum edge, produce hydroxyl radicals (·OH), and accelerate surface hydroxylation, which result in a significant improvement in the hydrophilicity and photoreactivity of Nd-doped TiO₂ thin films. When the content of Nd is 0.1% (mass fraction), TiO₂ thin films achieve the smallest grain size (about 15 nm), and the hydrophilic and photocatalytic activities of TiO₂ thin film reach the maximum, the contact angle is only 8.1°, and 92% of methylene blue is finally degraded. Moreover, the modification mechanism of Nd doping was also discussed.

Key words: TiO₂; Nd doping; sol-gel method; hydrophilicity; photocatalysis