一步溶剂热控制合成S掺杂TiO_2及其可见光催化处理水中六价铬的研究

One-step Solvothermal Synthesis of Sulfur Modified TiO_2 for Visible-Light Photoreduction of Aqueous Cr(VI)

以硫代乙酰胺为硫源,采用一步溶剂热合成S掺杂TiO_2催化剂,以水中六价铬为污染物模型,考察S-TiO_2在可见光下的催化活性.采用X-射线光电子能谱、X-射线粉末衍射、紫外-可见吸收光谱、傅里叶变换红外光谱、荧光发射光谱和N2吸附-脱附等技术对S-TiO_2进行表征.结果表明,硫原子以S6+形式取代TiO_2晶格中的Ti^(4+),形成Ti-O-S键;S-TiO_2对六价铬的可见光还原率均高于TiO_2.适量硫掺杂可降低催化剂的荧光发射光谱强度,提高了光生载流子的利用率,使得S-TiO_2的光催化活性增强.

Sulfur-dpoed TiO2 synthesized via a one-step solvothermal method was used as a pho- tocatalyst for Cr（Ⅵ） reduction under visible-light （λ〉420nm） irradiation. The composition and the optical property of the as-synthesized S-doped TiO2 were characterized by X-ray photoelectron spectroscopy （XPS）, X-ray powder diffraction （XRD）, Fourier transform infrared spectroscopy （FT-IR）, ultraviolet-visible absorption and diffuse reflectance spectroscopy, fluorescence spectrosco- py, and N2 adsorption-desorption. According to XPS and FT-IR, cationic S6＋ substituted part of Ti4＋ in the TiO2 lattice and formed a new bond of Ti-O-S. S-doped TiOz exhibited higher visible-light photocatalytic activity for reduction of the aqueous Cr（Ⅵ） than TiO2 particles,and the one with 10 mol% S doping percentage Opossessed the highest photocatalytic activity. S-doped TiO2 with suit- able Sdoping amount showed weaker fluorescent emission,thus improving the electro-hole separa- tion and exhibiting higher photocatalytic activity. Therefore, S-doped TiO2 may be a promising pho- tocatalyst in efficient utilization of solar energy for the treatment of Cr（Ⅵ） wastewater.