多级结构介孔稀土氧化物的制备及应用研究

【作者】 陆斌；

【导师】 李和兴；

【作者基本信息】 上海师范大学 ， 物理化学， 2008， 硕士

【摘要】 纳米介孔材料具有非常广泛的应用前景,吸引着许多科学家投身到这个领域的研究中。对于介孔材料而言,目前的发展方向主要集中在新型介孔材料的合成以及介孔材料的功能化和应用探索方面。而稀土氧化物由于其特殊的光学、电学、磁学、催化性能,近年来受到人们的广泛研究和应用。而合成具有纳米介孔结构的稀土氧化物,使其具有特定的形貌、尺寸、维度、孔结构的纳米材料,研究其物性和结构之间的内在关系,进而组装功能性纳米稀土材料,对纳米稀土科技的研究和发展具有重要的理论意义和现实意义。本论文采用不同途径合成了具有介孔结构的CeO2,并以CeO2为主要研究对象,深入研究了形貌与构性的关系,为开发具有特殊形貌的稀土介孔氧化物进行了有益的探索。全文共分为六章,第一章为背景介绍,第二着重介绍表征方法,重点内容包括以下四章。第三章通过浸渍法制备了SBA-15负载的稀土铈银介孔复合材料并应用于抗菌性能研究。研究表明,铈的存在有利于银纳米线均匀的镶嵌于SBA-15的孔道中,同时铈能明显增强银纳米线的活性。所制备的抗菌剂对金黄色葡萄球菌和大肠杆菌均有着优异的抗菌性能。第四章首次报导了利用含胺基的酚醛树脂为模板剂通过水热法制备了介孔氧化铈。通过XRD,BET,TEM等对产物的结构和形貌进行了详细的分析表征。产物经负载一定量的银后,经抗菌活性测试表明,对大肠杆菌和金黄色葡萄球菌具有较强的抑杀作用。第五章首次通过溶剂热法合成了具有核壳结构的CeO2,采用SEM、TEM、XRD、TG-DTA等测试手段,对核壳结构CeO2的形貌进行了详细的分析和表征,并详细讨论了其形成机理。所制备的核壳CeO2具有较大的比表面积和稳定的孔结构,对紫外光具有较强的吸收,可望作为一种高效的紫外吸收剂使用。本方法具有普遍的意义,它可以发展为一般的方法并应用到其它稀士化合物纳米材料的合成中。第六章以葡萄糖为模板剂通过水热法可控合成了具有核壳和空壳结构的介孔CeO2。研究发现通过调节不同水醇比和葡萄糖浓度可以实现空壳和核壳的可控转化。通过考察其转化条件,提出了CeO2核壳-空壳结构的合成机理。并运用这一机理,进一步合成了一系列核壳-空壳结构的稀土氧化物。为工艺简单、条件温和、结构可控的稀土介孔氧化物的合成探索出了一条新的途径。更多还原

【Abstract】 Nanostructure mesoporous materials have attracted extensive attention owing to their great potential applications. To date, most researches in mesoporous materials are focused on the synthesis of novel mesoporous materials and their functionalizations for application. Furthermore owing to the unique property of the electron, light, magnetism and catalysis, the mesoporous Rare-earth oxide have earned intensive research and application. The synthesizing of mesoporous rare earth oxide nanomaterials with special morphology, size, dimension and pore structure and studying the internal relationship between its physical properties and structures for further assembling functional rare earth nanomaterials are of theoretical and realistical significantion.In this paper, the mesoporous CeO2 was prepared through various methods meanwhile the relationship between the morphology and the structure and property has deeply studied, which attributed to the development of the rare-earth oxide mesoporous with special morphology. The whole paper has six charpters and the first charpter is the backgound introduction, the second is about the experiment and characterization, and the last four were noted as follows:In charpter three, the Ce and Ag composite supported on the SBA-15 was synthesized and applied in the research of antibacterial through impregnation method. The experiment result shows the exsitence of the Ce has a positive effect on the even distribution of the Ag nano wires in the pore channel, at the mean time, the Ce can greatly enhance the activity of the Ag nano-wires. The synthesized material has an excellent impact on killing the Escherichia coli and Staphylococcus aureus.In charpter four, the mesoporous CeO2 was prepared through hydrothermal method with phenolic resin functionlized with–NH2 as the template for the first time. The structure and morphology were characterizated by XRD, BET, TEM and so on. After loading the amount of Ag, according to the test of anti-bacterium, the material has high activity to the Escherichia coli and Staphylococcus aureus.In charpter five, the CeO2 with the morphology of core-shell was created by the solvent-thermal method firstly. With the help of SEM, TEM, XRD and TG-DTA, the morphology of the CeO2 was fully analysed and characterized, as a result of which the formation mechanism was also covered. The prepared core-shell CeO2 has a large surface area and stable pore structure and above all has strong adsorption of the ultra-violate,which maybe become a high efficiency UV shielding .The synthesis method used in this paper is universally significant, it can be developed into a general method and applied to nanomaterial synthesis of other rare earth oxides.In charter six, the mesoporous CeO2 with core-shell and hollow sphere was prepared with hydro-thermal methods using glucose as the template. Through the adjustment of ratio between the water and the ethanol and the concentration of the glucose, the realization of the change from the hollow sphere to the core-shell is aviliable. With regard to the change condition, the formation mechanism of the core-shell and hollow sphere was proposed, moreover using such mechanism, a series of other core-shell rare earth oxides were fabricated, which pave a way to a simple, moderate synthesize of the morphology-controllable mesoporous rare-earth oxide.更多还原