氮、硫改性纳米二氧化钛光催化降解有机废水的研究

【作者】 席战勇；

【导师】 于秀娟；

【作者基本信息】 黑龙江大学 ， 物理化学， 2008， 硕士

【摘要】 近年来,多相半导体光催化技术逐渐受到人们的重视。在这些催化剂中,TiO₂由于其氧化能力强、无毒并且稳定而被证明是适于在环境治理当中进行广泛使用。然而,由于TiO₂的带隙较宽（带隙能3.2eV）,因此它只能吸收紫外光,如果能将该催化剂的吸收波段拓展到可见光区将大大提高催化效率。本论文以钛酸四丁酯为钛源、胱氨酸为掺杂物,采用溶胶-凝胶法制备了N、S改性TiO₂光催化剂。对所制备催化剂采用了X-射线衍射、X射线光电子能谱、傅立叶变换红外光谱、表面光电压谱、漫反射光谱等多种测试手段进行表征。在红外光谱中发现了S=O（989 cm-1,1047 cm-1,1137 cm-1,1237 cm-1）及N-H（1401cm-1）峰的存在,与之相应的XPS谱表明N峰和S峰分别出现在399.8eV和401.8eV、168.8eV,分别归属于O-Ti-N、Ti-N-O、SO42-。DRS结果显示,所制备的N、S改性光催化剂在紫外和可见光区均有强吸收,吸收边向长波方向发生红移。研究了紫外及可见光下,所制备的N、S改性TiO₂光催化降解10mg/L罗丹明B的效能。在紫外光下,反应1h,罗丹明B的去除率达到81%。在380nm⁶30nm和470nm⁸00nm的可见光照射下,罗丹明B的去除率分别达到77%和75%。以PTFE为粘合剂制备了催化剂复合膜。制备复合膜最佳原料质量比4:1（N、S改性TiO₂:PTFE）,最佳负载量为37.5mg/cm2,所制复合膜在紫外光及可见光下具有与N、S改性TiO₂粉体催化剂相似的催化性能,光催化能力并未因固定化而降低。更多还原

【Abstract】 In recent years, heterogeneous semiconductor photocatalysis gradually becomes a popular technique. Among of them, titanium dioxide （TiO₂） has been proved to be the most suitable photocatalyst for widespread environmental applications because of its strong oxidizing power, non-toxicity and long-term stability. However, the photocatalysis widespread technological use with TiO₂ is impaired by its wide band gap （3.2eV）, which requires ultraviolet irradiation for photocatalytic activation. If the photocatalytically active region is expanded to the visible light region, sunlight or rays from artificial sources can be used more efficiently.In this work, N、S-comodified TiO₂ powders were prepared with tetrabutyl titanate and L-cystine via sol-gel method at room temperature. The as-prepared TiO₂ powders were characterized with X-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS）, surface photovoltage spectroscopy （SPS）, UV–Vis diffuse reflectance spectra （DRS）, infra-red spectrometry （IR）. From IR spectrum, S=O peaks （about 989cm-1, 1047cm-1, 1137cm-1, 1237cm-1） and N-H peak （1401cm-1） were observed.Corresponding to IR results, nitrogen （399.8eV, 401.8 eV） and sulfur （168.8ev） were found in XPS spectrum, which can attribute to O-Ti-N, Ti-N-O and SO42-, respectively. The results of DRS showed that the as-prepared TiO₂ powders exhibited a stronger absorption in the UV-Vis light region and an obvious red shift of absorption edge due to N、S-codoping.The photocatalytic activity was evaluated for the photocatalytic oxidation of Rhodamine B under UV light and daylight irradiation, respectively. The photocatalytic activity of the as-prepared N, S-co-doped TiO₂ powders in the ultraviolet light was kept （81%, 1h）. Simultaneously, its photocatalytic activity （380nm⁶30nm, 77%, 1h; 470nm⁸00nm, 75%, 1h） in the visible light. The immobilized photocatalyst film were prepared with PTFE as adhesives. The optimal ratio of photocatalyst and PTFE was 4:1, and the optimal loading content was 37.5 mg/cm2 during the preparation of immobilized photocatalyst film. The photocatalytic activity of immobilized photocatalyst film was as strong as powder in suspension system whatever under UV or Vis, The photocatalytic activity of catalyst doesn’t decrease because of loading.更多还原