TiO2/Attapulgite Nanocomposite as Photocatalyst: Impact of Phase Transition

摘要

TiO2/attapulgite (ATP) nanocomposites were synthesized by a low temperature hydrolysis method, and were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Fourier Transform Infrared (FT-IR) spectroscopy. Results indicate that the weight ratio of TiO2 to ATP has critical effect on the crystalline structure of TiO2. Weight ratios of M-TiO2/M-ATP at 0.25:1, 0.5:1 and 1:1 result in anatase TiO2, while M-nO(2)/MA-rp at 2:1 leads to the rutile phase. Anatase-rutile mixed TiO2 can be obtained at M-TiO2/M-ATP = 1.5:1, and the mixed phase composite demonstrates the highest photocatalytic activity for the degradation of methyl orange with a 99% conversion within 40 min under UV light irradiation. The enhanced separation of photogenerated electron hole pairs in mixed rutile-anatase is believed responsible for the improvement of photocatalytic activity.