Direct synthesis of Nd³⁺ doped mesoporous TiO₂ and investigation of its photocatalytic performance

Nd³⁺ doped mesoporous TiO₂ samples with different molar ratio of Nd/Ti were synthesized by a sol-gel method. The textural and optical properties of the samples were systematical characterized by X-ray diffraction, transmission electron microscopy, N₂ adsorption-desorption isotherms, Fourier transform infrared spectroscopy and UV-Visible absorbance spectroscopy. It was revealed that Nd³⁺ doping inhibited the phase transformation from anatase to rutile after calcination, and the mesoporous structure of doped samples was still retained with the increase of Nd/Ti molar ratio. The surface area of the samples varied from 137 to 210 m²g^-1 and the average pore size of them ranged between 5.7 and 8.2 nm. The photocatalytic activities of all the samples were evaluated by degradation methyl orange (MO) in aqueous solution as a model reaction under UV light irradiation. The results showed that the doped samples demonstrated a higher photocatalytic activity than the mesoporous TiO₂, and the 3 mol% Nd³⁺ doped mesoporous TiO₂ exhibited the best photocatalytic performance. Meanwhile, a promotion effect of the H ₂O₂ added was verified in the degradation of MO.