Synthesis of Gd-N codoped porous TiO2 photocatalyst and its enhanced photocatalytic activities

Abstract

Visible-light-active Gd-N codoped porous TiO2(Gd-N-TiO2) photocatalyst was fabricated by an evapora-tion-induced self-assembly route using surfactants as structure-directed agents. As-prepared samples were characte-rized by X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy(TEM), X-ray photoelectron spectroscopy, Brunauer-Emmett-Teller(BET) method, and ultraviolet-visible absorption spec-troscopy. The results indicated that synergistic reaction occurred when codoping with Gd3+ and N, which enhanced the light absorption properties of TiO2. Irregular worm-like particles with wide interparticle spaces were clearly observed by TEM. The average particle size of Gd-N-TiO2 decreased to ca. 8 nm because co-doping inhibited the particles growth significantly. Thus, the specific surface area of Gd-N-TiO2(198.7 m2/g) was higher than that of Degussa P25 TiO2(50 m2/g). Gd-N-TiO2 exhibited a high photocatalytic activity toward methyl orange degradation under UV-Vis or visible-light irradiation. The Gd-N-TiO2 catalyst also presented a stable performance without losing activity after four successive photocatalytic experiments. The facile synthesis and excellent activity of Gd-N-TiO2 indicated its great potential as industrial catalysts for wastewater treatment.