Preparation, characterization of sulfur-doped nanosized Ti[O.sub.2] and photocatalytic degradation of methylene blue under visible light

• Published in: Catalysis letters 2010-10, Vol.139 (1-2), p.77
• Main Authors: Ang, Thiam Peng, Law, Jia Yan, Han, Yi-Fan
• Format: Article
• Language: English
• Subjects: Chemical properties; Comparative analysis; Diffraction; Infrared spectroscopy; Sulfates; Sulfur; X-ray spectroscopy; X-rays
• ISSN: 1011-372X; 1572-879X
• DOI: 10.1007/s10562-010-0390-4

Sulfur-doped Ti[O.sub.2] catalysts were prepared by a mechanochemical method. The prepared catalysts exhibited photocatalytic activity in methylene blue degradation under visible light. The catalyst structure has been characterized using UV-visible spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), transmission electron microscopy (TEM), thermogravimetry analysis (TGA) as well as Fourier transform infrared spectroscopy (FT-IR). UV-visible spectroscopy revealed that the absorption edge of the doped Ti[O.sub.2] was red-shifted compared with bare Ti[O.sub.2]. XRD patterns suggested that the brookite phase became more prevalent with increasing ball milling duration. In addition, surface sulfate species were detected by FT-IR, XPS and TGA. We deduce the rise of catalytic activity is due to the synergetic effect between the brookite phase and the anatase phase that would probably retard the electron-hole recombination. On the other hand, methylene blue was found to be N-demethylated during the irradiation thus giving rise to blue-shifting of peak at 664 nm in UV-visible spectroscopy.