【作者】 关卜源；

【导师】 霍启升；

【作者基本信息】 吉林大学 ， 无机化学， 2014， 博士

【摘要】 近年来科学家们一直对介观纳米复合材料有着浓厚的兴趣。这类材料具有纳米级尺寸，较高的比表面积和大的孔体积，这使它们可以应用于吸附，催化，能源存储，药物缓释和细胞传递等诸多领域。纳米粒子的结构和组成是实现这些性能的关键。在介观纳米复合材料中，介孔氧化硅纳米复合材料已经被广泛使用。它们可以通过精确控制溶胶-凝胶过程而合成出来，表面修饰过程简单，并且具有很好的生物相容性和低的细胞毒性。然而其他介观纳米材料或纳米复合材料也具有较大的优势，如介孔有机硅材料具有较好的水热稳定性和机械稳定性，孔道的疏水性，以及骨架内含有高浓度的有机官能团；碳纳米材料具有比表面积大，导电性，疏水性，化学和热稳定性和生物相容性等特点；酚醛树脂是最常用的碳前驱体之一具有优异的物理化学性质，如良好的碳产率，易于官能化，疏水性，和热稳定性；氧化锆，氧化钛和它们的二元氧化物已被广泛地用于许多领域，包括催化，光催化，染料敏化太阳能电池，光致发光，毛细管电泳，层析，无机颜料，介电陶瓷，重金属离子和放射性废物封存剂等。这些性能很多都是氧化硅材料所不能比拟的，所以开发合成其他介观结构纳米材料或纳米复合材料的通用方法至关重要。1.我们设计并实现了一种合成具有良好分散性高度有序介观结构的有机硅纳米粒子（PMONs）的通用方法。这种方法采用一种简单的阳离子表面活性剂十六烷基三甲基溴化铵（CTAB）和具有有机桥连基团的简单有机硅源通过氨催化的溶胶-凝胶反应生成介孔有机硅纳米粒子。通过改变有机硅源中的桥联基团合成出具有三维六方（P63/mmc），立方（Pm3n），二维六方（p6mm）和蠕虫状介观结构的纳米粒子。通过粉末X-射线衍射分析（XRD）和透射电子显微镜（TEM）证明介观结构的合理性。纳米粒子的粒径可以通过调节反应介质中氨水浓度或共溶剂的含量而进行控制，范围从30nm至500nm。介孔有机硅纳米粒子的骨架中具有高浓度的有机基团，使这类纳米粒子具有良好的热稳定性，在低极性溶剂中具有良好的分散性和对疏水性小分子较高的吸附能力。在细胞实验中，染料功能化的介孔有机硅纳米粒子显示出低的细胞毒性和优良的细胞穿透性，这使这类粒子在医药领域应用潜力巨大。2.我们设计并实现一个非常简单的协同自组装包覆方法来合成酚醛树脂和碳的核-壳，空心和蛋黄-蛋壳纳米复合材料。这种方法的特色是在包覆过程中阳离子表面活性剂CTAB提高了反应介质中核粒子的分散性并同时作为介观结构间苯二酚-甲醛树脂形成的软模板，这种方法可以将聚合物和微孔碳外壳均匀的包覆在具有不同表面性质的功能核粒子上。核-壳纳米复合材料的核直径和外壳厚度可以被精确地控制。这种方法具有高度的可重复性并有较大的产量。数克聚合物或碳纳米复合材料可以容易地通过一锅反应制备。以硼氢化钠作为还原剂，具有疏水性外壳的金@碳（Au@C）蛋黄-蛋壳复合材料催化剂在水溶液中还原疏水的硝基苯比亲水的4-硝基酚的速率更快，这使催化剂@碳蛋黄-蛋壳纳米复合材料具有作为疏水分子选择性催化剂的应用前景。3.为连续催化反应设计空心的介孔纳米催化剂可以为纳米结构的发展注入新的活力。在这项研究中，我们设计并实现一个通用的协同自组装包覆方法合成空心和蛋黄-蛋壳介孔钛锆氧化物纳米球，这类纳米材料具有可调的组成（ZrO2含量从0到100％可以调节），较高的比表面积（465m2g-1）和均匀的介孔。该包覆过程中，所用的十六胺（HDA）作为软模板与锆和钛的前驱体通过协同自组装包覆在硬模板氧化硅球上形成核-壳纳米结构。通过在氨水溶液中处理并在空气中焙烧，氧化硅@介孔钛锆氧化物纳米球可被转化为均一的空心钛锆氧化物纳米球。使用核-壳氧化硅纳米复合材料代替氧化硅纳米球作为硬模板，通过相同包覆和刻蚀过程，合成方法可以进一步拓展合成蛋黄-蛋壳结构的纳米复合材料。这种方法与通过核粒子，软模板CTAB和氧化硅前驱体自组装合成核-壳介孔氧化硅纳米复合材料相似，并且可以扩展为一种用介孔钛锆氧化物包覆其他常用硬模板（例如，介孔氧化硅球，介孔有机硅球，聚合物球和碳纳米球）的通用方法。钛锆氧化物外壳中介孔孔道的高通透性已被4-硝基苯酚与金@介孔钛锆氧化物蛋黄–蛋壳纳米催化剂的反应所证实。此外，包括酸催化和加氢还原两个步骤合成苯并咪唑衍生物连续催化反应，可以通过使用含有钯核和具有酸性的介孔钛锆氧化物外壳的双功能蛋黄-蛋壳催化剂来实现，这使得空心介孔钛锆氧化物纳米球可能成为实用的催化剂。4.可以生物降解的蛋黄-蛋壳介孔氧化锆纳米粒子具有潜在的医学应用前景。我们设计并制备了钛掺杂的氧化锆纳米粒子。维生素C可从氧化锆粒子中去除钛并加速其在模拟人体环境中的降解速率。更重要的是，它表现出了非常特别的“一个接一个”的降解过程。本论文在前人工作的基础上，发展出合成高度有序介孔有机硅纳米材料，介观结构酚醛树脂和微孔碳复合材料和介孔钛锆氧化物复合材料的通用性方法，为这些材料在其他领域的应用提供了帮助。更多还原

【Abstract】 Significant research efforts in recent years have been devoted to the developmentof mesostructured nanocomposites for applications in diverse fields. Their nanoscaledsize, high surface area and large porosity make ordered mesoporous nanoparticlesuseful in adsorption, catalysis, energy storage, controlled drug release, and cellulardelivery. The structure and composition of the nanocomposites are key to theachievable properties. Among mesostructured nanocomposites, mesoporous silicananoparticles have been extensively synthesized by a well-controllable sol–gelprocess due to facile surface modification potential, biocompatibility and low toxicity.Periodic mesoporous organosilica materials have some advantages over periodicmesoporous silica materials, such as excellent hydrothermal and mechanical stability,hydrophobic property within the pore wall, and high concentration of organicfunctional group in the framework; carbon nanomaterials are very attractive due totheir fascinating features such as large surface area, electrical conductivity,hydrophobic property, chemical and thermal stabilities, and biocompatibility;phenol–formaldehyde resin, one of the most popular carbon precursors, is also a goodsolid support due to its excellent physicochemical properties, such as good carbonyield, easy functionalization, hydrophobicity, and thermal stability; zirconia, titaniaand their binary oxides have been widely employed in many fields including catalysis,photocatalysis, dye-sensitized solar cells, photoluminescence, capillaryelectrophoresis, chromatography, inorganic pigments, dielectric ceramics, and heavymetal ion and radioactive waste sequestration. Therefore, it is highly desirable todevelop a simple and reproducible route to prepare other mesostructurednanocomposites.A general synthetic procedure for highly ordered and well-dispersed periodic mesoporous organosilica (PMO) nanoparticles is designed and achieved based on asingle cationic surfactant cetyltrimethylammonium bromide (CTAB) and simple silicasources with organic bridging groups via an ammonia-catalyzed sol–gel reaction. Bychanging the bridging group in the silica sources, the pore structures of the as-madeparticles with three-dimensional hexagonal (P63/mmc), cubic (Pm3n),two-dimensional hexagonal (p6mm), and wormlike structure were evidenced bypowder X-ray diffraction analysis (XRD) and transmission electron microscopy(TEM). The size range of the nanoparticles can be adjusted from30nm to500nm byvariation of the ammonia concentration or the co-solvent content of the reactionmedium. The PMO nanoparticles with high concentration of organic groups in theframework offered good thermal stability, good dispersion in low polarity solvent andhigh adsorption of small hydrophobic molecules. Finally, the dye functionalized PMOnanoparticles show low cytotoxicity and excellent cell permeability, which offersgreat potential for biomedical applications.A very simple cooperative template-directed coating method is developed for thepreparation of core-shell, hollow, and yolk-shell microporous carbon nanocomposites.Particularly, the cationic surfactant CTAB used in the coating procedure improves thecore dispersion in the reaction media and serves as the soft template formesostructured resorcinol–formaldehyde resin formation, which results in the uniformpolymer and microporous carbon shell coating on most functional cores with differentsurface properties. The core diameter and the shell thickness of the nanocompositescan be precisely tailored. This approach is highly reproducible and scalable. Severalgrams of polymer and carbon nanocomposites can be easily prepared by a facileone-pot reaction. The Au@hydrophobic microporous carbon yolk–shell catalystfavors the reduction of more hydrophobic nitrobenzene than hydrophilic4-nitrophenol by sodium borohydride, which makes this type of catalyst@carbonyolk–shell composites promising nanomaterials as selective catalysts for hydrophobicreactants.The design of hollow mesoporous nanostructures for cascade catalytic reactionscan inject new vitality into the development of nanostructures. In this study, we design and achieve a versatile cooperative template-directed coating method for thesynthesis of hollow and yolk–shell mesoporous zirconium titanium oxide nanosphereswith varying compositions (ZrO2content from0to100%), high surface areas (465m2·g–1) and uniform mesopores. In particular, the hexadecylamine (HDA) used in thecoating procedure serves as a soft template for silica@mesostructured metal oxidecore–shell nanosphere formation. By a facile solvothermal treatment route with anammonia solution and calcination in air, the silica@mesostructured zirconiumtitanium oxide spheres can be converted into highly uniform hollow zirconiumtitanium oxide spheres. By simply replacing hard template silica nanospheres withcore–shell silica nanocomposites, the synthesis approach can be further used toprepare yolk–shell mesoporous structures through the coating and etching process.The approach is similar to the preparation of mesoporous silica nanocomposites fromthe self-assembly of the core, the soft template cetyltrimethylammonium bromide(CTAB) and a silica precursor and can be extended as a general method to coatmesoporous zirconium titanium oxide on other commonly used hard templates (e.g.,mesoporous silica spheres, mesoporous organosilica ellipsoids, polymer spheres, andcarbon nanospheres). The presence of highly permeable mesoporous channels in thezirconium titanium oxide shells has been demonstrated by the reduction of4-nitrophenol with yolk–shell Au@mesoporous zirconium titanium oxide as thecatalyst. Moreover, a cascade catalytic reaction including an acid catalyzed step and acatalytic hydrogenation to afford benzimidazole derivatives can be carried out veryeffectively by using the accessible acidity of the yolk–shell structured mesoporouszirconium titanium oxide spheres containing a Pd core as a bifunctional catalyst,which makes the hollow zirconium titanium oxide spheres a practicable candidate foradvanced catalytic systems.Biodegradable yolk-shell mesoporous zirconia nanoparticles with potentialmedical applications have been designed and prepared by doping Ti into the shells ofnanoparticles. Vitamin C can remove the Ti from the zirconia particle shells andaccelerate their degradation in a simulated human body environment. Moreimportantly, it showed a very distinctive “one by one” degradation process. In summary, we develop three general methods for the preparation of highlyorder mesoporous organosilica nanoparticles,, mesostructured phenol-formaldehyderesin and microporous carbon core-shell nanocomposites, and mesoporous zirconiumtitanium oxide core-shell nanocomposites, which offers great potential forapplications in various fields.更多还原