【作者】 高标；

【导师】 魏子栋；

【作者基本信息】 重庆大学 ， 化学工程与技术， 2010， 硕士

【摘要】 近年来,光化学、光催化以及催化化学已经成为化学学科中最活跃的研究领域。特别是光催化领域,利用半导体光催化剂把光能转化为电能或化学能已经成为最热门的研究领域之一。伴随着在半导体光催化剂方面的研究,有关层状结构的化合物也引起了人们的广泛关注。研究表明,层状化合物在光催化等催化领域具有很大的应用潜力。钛酸盐中的钛酸钾就是一种典型的半导体型的层状金属化合物,它作为光解水的光催化材料,己有研究报道。在本文的研究中,我们将K2CO3和TiO2通过高温固相反应制得四钛酸钾（K₂Ti₄O₉）,四钛酸钾经酸化处理后得到四钛酸（H₂Ti₄O₉）。利用高温固相反应,尿素作为氮源分别对四钛酸钾（K₂Ti₄O₉）和四钛酸（H₂Ti₄O₉）进行氮掺杂,反应得到氮掺杂的K₂Ti₄O₉和H₂Ti₄O₉。采用X射线衍射（XRD）、红外光谱（IR）、紫外可见漫反射光谱（UV—DRs）等方法对材料结构进行表征。X射线衍射结果表明四钛酸钾与尿素反应后,层间距加大,紫外可见漫反射光谱（UV—DRs）结果表明氮掺杂催化剂可见光光波段光吸收能力明显增强,通过红外光谱（IR）发现氮掺杂过后,N确实与钛酸钾骨架发生了化学作用。利用自行设计的反应器,研究了氮掺杂催化剂对亚甲基蓝模拟染料废水的处理,取得了较好的去除效果。研究了不同氮掺杂改性温度对K₂Ti₄O₉在紫外及可见波段下催化活性的影响,同时也考察了氮掺杂之前洗涤与否对氮掺杂催化剂催化活性的影响,并通过其亚甲基兰的光催化降解分析其光催化性能变化,通过紫外可见漫反射光谱（UV—DRs）表征了不同温度下氮掺杂催化剂样品的吸光能力变化。将制备的氮掺杂四钛酸钾（N-K₂Ti₄O₉）做催化剂制成薄膜光电催化电极,通过降解亚甲基蓝来测试催化活性,研究催化剂在光电催化方面的应用潜力。结果表明:氮掺杂改姓焙烧温度对N掺杂也具有相当重要意义,不同温度掺杂催化剂颜色明显不同,对光的吸收及光催化活性相差明显:氮掺杂后催化剂呈黄色,对可见光波段吸收能力明显增强;N掺杂钛酸盐的可见光活性强于其对应的四钛酸。N-K₂Ti₄O₉薄膜光电催化降解亚甲基蓝的效率要明显高于其光催化降解的效率。与光催化相比,N-K₂Ti₄O₉薄膜光电催化对亚甲基蓝的催化降解更加地彻底,不仅破坏其发色基团,而且分解其苯环共扼体系。更多还原

【Abstract】 In recent years, photochemistry, photocatalysis and catalytic chemistry have been the most active research areas, especially in the photocatalysis field, the light energy transformation into electric energy and chemical energy. Research has shown that layered compound has great potential in catalysis such as the photocatalysis field. Potassium titanate is a typical semiconductor-based layered metallic compound. It has been reported as a photocatalyst for water splitting.In this study, precursor potassium tetratitanate （K₂Ti₄O₉） was prepared the by solid-phase reaction between K2CO3 and TiO2. Protonic layered tetratitanate（H₂Ti₄O₉） was obtained by subsequent acidification of K₂Ti₄O₉ with HCl （1M） solution. The nitrogen-doped photocatalyst was obtained by solid state reaction between H₂Ti₄O₉ and urea, which was served as the source of nitrogen. X-ray diffraction （XRD）, infrared spectroscopy （IR）, ultraviolet-visible diffuse reflectance spectroscopy （UV-DRs） were used to characterize the prepared material. Results showed that the resulting nitrogen-doped layered K₂Ti₄O₉ compounds had a larger interlayer space than their precursor. UV-Vis diffuse reflectance spectroscopy （UV-DRs） results show that the visible light absorption capacity of nitrogen doped catalysts significantly enhanced. This specific structure of the nitrogen-doped K₂Ti₄O₉（N-K₂Ti₄O₉） led to an enhanced adsorption capacity in visible light wave band compared with its precursor. By IR spectroscopy analysis, it is found that there are chemical reaction that occurs between nitrogen and the potassium titanate skeleton.The photocatalytic degradation of methylene blue was investigated in a self-made photoreactor. The doped nitrogen temperatures play an important role in photocatalytic activity of K₂Ti₄O₉ under UV light and visible light. The results indicated that different temperatures of N-doped photocatalysts result in different depth colour of photocatalysts,and the different ability of light absorption. The Nitrogen-doped H₂Ti₄O₉（N-H₂Ti₄O₉） show better photocatalysis for degradation of methylene blue under visible light wave band than H₂Ti₄O₉; while N-doped K₂Ti₄O₉ show higher electro-photo-catalytic activity in the visible light wave band than its photo-catalytic activity. Compared with the photocatalysis, N-K₂Ti₄O₉ film photoelectrocatalytic on photocatalytic degradation of methylene blue more thoroughly, not only the destruction of their chromophore, but also decomposition of the benzene ring conjugate system.更多还原