【作者】 杨槐馨；

【导师】 谢克昌； 李瑞丰；

【作者基本信息】 太原理工大学 ， 工业催化， 2002， 博士

【摘要】 论文着重讨论了纳米NaY分子筛的合成、晶体生长机理及金属配合物／FAU纳米复合材料的性能和沸石主体的纳米效应。 一．纳米NaY沸石的合成及层状晶化机理的提出 纳米沸石作为纳米材料的一个重要组成部分，在分子筛成核及生长机理的研究、超细分子筛膜的制备、催化及光化学载体的研究中倍受关注。已报道的纳米八面沸石的合成技术，条件要求苛刻、可操作性较差、反应成本高且对环境造成不同程度污染。本论文致力于一种新的纳米八面沸石合成技术的开发，及其物理化学性能及晶化机理的研究。 1．采用两步法，在不加任何添加剂，常温配料，应用常规设备的情况下合成了粒度30nm-70nm的NaY沸石，并通过改变晶化条件或配料合成了30nm-550nm的多种硅铝比相近，不同颗粒大小的超细NaY沸石。 2．采用FTIR、TG-DTA、DRS和BET等表征手段对粒度在550nm到70nm的一系列硅铝比相近的Y型分子筛的物理化学性能进行了系统研究。结果发现，随着分子筛粒度的减小，物化性能发生系统变化：FTIR位于1000cm^-1，700cm^-1附近的伸缩振动峰向高频方向移动，其余大部分吸收峰发生红移；DRS谱图中246nm附近的峰向低频反向移动；粒子间二次孔增多，中孔孔容增大，样品的BET比表面逐渐增加；²⁹Si MAS NMR谱图中主峰的半峰宽明显拓宽，不对称性增强。 3．根据HRTEM、XRD、FTIR对不同反应时间反应体系中固体产物的跟踪研究，提出了一种新的层状晶体生长机理；初始硅铝凝胶以直径40nm-50nm的无定性球型颗粒聚集，并沿733晶面生长形成层状结构，层状结构进一步延伸生成立方晶相的八面沸石。 二．金属配合物／FAU纳米复合材料的制备、性能和沸石主体的纳米效应 在分子筛的孔腔中组装或封装金属配合物所制备的金属配合物／分子筛复合催化材料具有酶催化剂的基本特性，温和的反应下，仍表现出高的反应活性和选择性、易与产物分离、可重复使用、位分离、择形性等效应，集传统的均相催化剂和多相催化剂的优越性于一体，是一种极具潜力的新型催化材料。但金属配合物的引入部分堵塞分子筛的通道，使配体、反应物及产物的扩散阻力增加，对这一材料的制备及催化性能造成不良影响。具体表现为:采用自由配体法制备时，金属配合物负载量难以提高;催化反应中，金属配合物负载量增加到一定程度，其催化转化数随负载量增加而剧烈降低。 纳米分子筛表面积大，晶内扩孜通道缩短，采用纳米分子筛作为主体，有望使金属配合物/分子筛复合催化剂的制备及催化过程中的扩散问题得以改善。_且纳米材料丰富的催化活性位，独特!勺表面性能，高的表面原子比及表面能也有可能赋介这一材料一些新的特性。 本文采用自由配体法和沸石合成法，制备了多种金属配合物/纳米分子筛主客体复合材料，利用多种不同的物理化学技术和催化反应对其进行了表征，旨在通过这一研究揭示金属配合物/F AU复合材料的制备、性能和沸石主体的纳米效应。自山配体法制备金属配合物/FAU纳米复合材料及其物化性能研究采用自由配体法，以30nm一70nm的纳米Y和ZOnm的纳米X为主体，制备了多种金属配合物/FAU纳米复合材料，并采用多种表征手段研究了金属配合物/F AU纳米复合材料制备及性能中的沸石主体的纳米效应，并首次将其应用于催化反应。各种现代技术（XRD、FTIR、TEM、DRS）分析表明，采用纳米分子筛作为主体，是解决金属配合物/FAU分子筛复合催化剂的制备及催化过程中的扩散问题的有效方法。和普通的FePhe川FAU复合材料相比较，提高，FePhe川nano一x及FePhe可nano一Y纳米复合材料中配合物负载量显著配合物在分子筛晶体中的分布更加均匀。于其中的余属配合物的性能也有很大缈响:DRS纳米分子筛主体性能对封装潜图件，的特征峰相对峰强度发生变化，说明了纳米分子筛表面性能和空间结构对配合物的生成及其空间构型产生影响。在同样的抽提条件下，纳米分子筛作主体，有利于负载配合物在处理过程中的氧化。热分析结果表明，由于纳米沸石主体的存在，客体金属配合物的分解温度有较大提高。环己烷催化结果表明:采用纳米分子筛作主体，晶内扩散阻力减小，有利于反应物和产物与活性位的接触与脱离，从而使此催化剂活性得以改善。 纳米主体的本征性能对复合材料的制备及催化性能也存在明显影响:Nano一Y分子筛主体在制备条件下都具有高的稳定性能，nano一X的骨架结构遭到不同程度的破坏。其中以Mnsalell*/11ano一X制备过程中的骨架破坏最为严重。金属配合物/11ano一Y纳米复合材料以HZO:和TBHP为氧化剂较金属配合物/NY复合材料有较高的活性及环氧化物选择性。Mnsalen*、Mnsalen/nan。一x及MnbiPy/nall。一X以TBHP为氧化剂较金属配合物胭Y复合材料有较高的活性、以HZO:为氧化剂反应活性很低。三.沸石合成法制备金属配合物/FAU纳米复合材料及其物化性能研究 沸石合成法同模板剂合成法相比，所固定或封装的金属配合物组成确定，催化剂中不含未被配合的金属离于或配体。对某些稳定性较差的纳米分子筛而?更多还原

【Abstract】 This dissertation includes two parts: the first part discusses the synthesis of nano-zeolite Y and the proposal of a new ’layer-by-layer’ zeolite crystallization mechanism; the second part invoves the preparation and charaterization of metal complex/faujasite nano-materials.1. Synthesis of nano-zeolite Y and the proposal of a new ’layer-by-layer’ zeolite crystallization mechanismThe synthesis of nano-meter zeolites has recently received much attention owing to their utility in the fundamental studies of zeolite crystal growth, in the preparation of ultra-thin zeolite films and nano-composites, and as a support for catalytic and photochemical reactions. The synthesis approach of nanosized faujasite reported in literature show disadvantages when using high shear agitation (not less than 3000rpm) or thermal shattering techniques, aging at very low temperature and adding organic compounds to the reaction mixture. In this paper, our attention paid on the development of a new nanosized faujasite synthesis approach, study of physical-chemical properties of nanosized faujasite, as well as the study of zeolite crystallization mechanisms.(1) Well-crystallized nanometer-sized zeolite Y of particle size less than 70nm (denoted as nano-Y) have been successfully synthesized for the first time by a two-step-process in an organic free system, without using any unusual techniques. Several types of zeolite Y of different particle sizes with similar Si/Al ratio have also been synthesized by adjusting the temperature and water content.(2) XRD. FTIR. TG-DTA, DRS, NMR and BET characterizations of these macrocrystalline and nanocrystalline materials all show that their physicochemical properties change systematically with crystal size: as the particle size decreases, the XRD lines of the samples bordene; the bands around 700cm-1 and 1000 cm-1 of FTIR patterns shift to the lower frequencies;the specified surface area and mesoporosity of the samples increase; DRS adsorption thresholds shift towards the longer wavelengths (attributed to the change of the particle size but also the degree of aggregation). (3) Based on our HRTEM, XRD, FTIR experimental studies and a systematical analysis, we proposed a new ’layer-by-layer’ mechanism for zeolite crystallization in the present system: the aluminosilicate precursor gel contained small amorphous particles of about 40 run that agglomerated during the beginning of the crystallization to form a layered structure along <733>, the layered structure then further crystallized to the cubic structure of zeolite Y.2. Nano-host effect on the preparation and physicochemical properties of the complex/faujasite nano-compositesMetal complexes immobilized into molecular sieves have gained great interest and become a hot point in the field of catalytic materials due to their mild reaction conditions, high catalytic activity and selectivity, easy separation, recovery, shape selectivity and unique site isolation. However the immobilized metal complexes partly clog the channel of zeolite, which makes the diffusion of ligands, reactants and product difficult. The diffusion problem causes a low complex loading content and heterogeneity of the immobilized metal complexes in the zeolite crystal. Activities of these materials are also not satisfactory due to the diffusion problems, especially when the amount of complex loaded in the zeolites increases.Large surface area and short diffusion pathways of nano-sized zeolites could possible be one solution to this question, which has not been remarked on in the literature until now. The special properties of nano-zeolite, such as possession of a highly catalytic center, high surface-atom ratio, large surface area, high surface energy and better retro-wear may also give this material some new application.In this paper we report the synthesis of a series of complex/nano-faujasite materials by a template synthesis method and a zeolite synthesis method. The guest/host nano-materials are further studied by various p更多还原