【作者】 杨圣军；

【导师】 梁国正；

【作者基本信息】 苏州大学 ， 材料学， 2014， 博士

【摘要】 柱撑粘土材料（简称为PILC）是一种具有类分子筛结构的新型多孔材料，可作为催化剂、吸附剂等功能材料，而广泛应用于石油化工、环境治理等诸多领域。然而，常规PILC的孔分布以微孔为主、且热稳定性在300~400℃内，在很大程度上限制了其进一步的推广应用。随着SiO2柱撑粘土材料（简称为SPC）的成功合成，为上述问题的解决提供了新途径。SPC材料具有孔道结构规整、孔径分布在超大微孔和介孔范围内、比表面积大、耐高温以及材料的可设计性强等突出优点，正受到越来越多科研工作者的重视。但SPC层间柱体为纯SiO2，自身的酸活性位有限、催化活性低；作为PILC领域的一个年轻分支，关于SPC的改性和修饰方面的研究也非常有限。因此，开展具有介孔结构的功能性PILC的研究具有重要的理论意义和巨大的应用价值。本文针对现有PILC材料发展的趋势、SPC材料的合成特点以及催化领域对PILC材料的要求，提出“层间模板法制备柱撑蒙脱石材料及其结构与性能”的研究。以层间模板法技术为核心，设计、制备了一系列的新型柱撑蒙脱石材料，考察基质粘土、柱撑化合物的种类以及金属、非金属原子掺杂改性对材料结构与性能的影响，构建材料结构与性能的关系，以期获得具有规整的介孔结构和优异的热稳定性、水热稳定性的柱撑蒙脱石材料，并能够满足某些有机反应体系对其催化性能的要求。具体的研究工作包括以下五个方面。首先，分别以内蒙古钙钠基蒙脱石和浙江钠基蒙脱石为原料，通过层间模板法合成了两种SPC材料（简称为SPC-NM和SPC-ZJ），系统研究了不同基质蒙脱石对SPC材料结构与性能的影响。研究结果表明，两种SPC材料都具有规整的介孔结构和典型的平板狭缝状孔道结构，但SPC-ZJ中存在蒙脱石片层结构部分剥离的现象，并存在一定数量的外露的介孔SiO2结构，导致其水热稳定性劣于SPC-NM材料；两种SPC材料都具有优良的热稳定性，在重油催化裂化反应中，SPC-ZJ体系具有更高的转化率，但汽油的选择性和循环使用性能不如SPC-NM。其次，建立了高铁含量掺杂改性SPC材料（Fe-SPC）的新方法，该方法以乙醇-水的混合体系为溶剂，有效地改善了Fe3+在硅溶胶中的分散状态，并有利于提高材料中Fe原子的掺杂量（Fe2O3含量可达27.03wt.%）。在此基础上，系统研究了铁源添加量对Fe-SPC材料的结构与性能的影响。研究结果表明，Fe-SPC具有规整的介孔结构，比表面积、孔径分布和孔容等与铁源的添加量有关；Fe原子主要以四面体形式掺杂于层间域SiO2柱体中（骨架铁），并伴有一定量的非骨架铁（八面体型）生成；该材料具有良好的水热稳定性，但热稳定性较差；其对模拟油和焦化苯的氧化脱硫反应体系具有优异的催化活性和循环使用性能，特别是焦化苯的氧化脱硫反应。第三，针对Fe-SPC材料中非骨架铁易团聚的问题，设计合成了一种铁原子高度掺杂的(Fe,Si)-PILC材料，并系统研究了该材料的结构与性能。研究结果表明，铁原子以四面体骨架铁的形式掺杂在SiO2骨架内，未发现非骨架铁的存在；(Fe,Si)-PILC具有类似SPC的片层结构和规整的介孔结构，SiO2骨架内铁原子的掺入也会造成其孔结构发生了一定的变化，但变化的幅度明显小于上述Fe-SPC材料；(Fe,Si)-PILC具有优异的热稳定性（优于Fe-SPC）和水热稳定性。(Fe,Si)-PILC对苯酚羟基化反应（对四面体铁敏感）具有较好的催化活性和循环使用性能。第四，设计合成了一种具有规整介孔结构的TiO2柱撑蒙脱石材料（Ti-PILC），避免了传统工艺中采用强酸的合成条件，并深入探讨了阳离子表面活性剂种类对Ti-PILC材料的结构与性能的影响。研究结果表明，Ti-PILC材料具有类似SPC的规整的介孔结构，有机模板剂的种类与材料孔结构的关系紧密，特别是材料的平均孔径；Ti-PILC材料的层间域TiO2柱体属于锐钛矿型，具有优越的紫外光催化降解亚甲基蓝的性能和循环使用性能，反应速率与催化剂的用量、材料的结构特性有关。最后，针对Ti-PILC材料在可见光下活性弱的问题，制备了一种氮原子掺杂的(Ti,N)-PILC材料，并系统研究了氮的掺杂对(Ti,N)-PILC材料的结构与性能的影响。研究结果表明，氮原子掺杂改性对材料的结构的影响不明显；氮原子的掺杂增强了层间域TiO2柱体对可见光的吸收能力，使得(Ti,N)-PILC在可见光照射条件下对亚甲基蓝的降解反应也具备了一定的催化活性。更多还原

【Abstract】 Pillared interlayered clays (coded as PILCs), a family of porous materials withzeolite-like structure, could be used as catalysts and adsorbents in many fields, such aspetrochemistry, enviromental protection and so on. However, the microporous structureand relatively low thermal stabilty (300~400℃) restrict their development and application.Recently, a new type of PILCs called silica pillared clays (coded as SPCs) was sucessfullysynthesized, which provides some enlightenment on solving above problems. SPCs haveordered porous structure, pore size distribution between super-micropore and mesopore,bigger special surface area, good thermal stabilty and designable structure, and thus havereceived more and more attentions. But the intra-gallery pillar of SPCs is pure silica, whichhas weak surface acidity and low catalytic performance. As a young branch of PILCs, thestudy on modification of SPCs is very limited. Therefore, functionalization of SPCs is oneissue with great importance in both theory and application.According to the development of present PILCs, the synthesis characteristics of SPCs,and the new requirements of catalysts, this thesis focuses on the study of mesoporousPILCs synthesized by an intra-gallery templating method (coded as IGT) and their catalyticperformances. Here, a series of new PILCs were designed and prepared by IGT, and theinfluence facors, such as basic clay, pillaring agent, modification with metal or non-metalelement, on the structure and properties of these PILCs were investigated Finally, it isexpected to obtain new types of PILCs with ordered gallery mesoporous structure,excellent thermal stabilty and hydrothermal stability as well as good catalytic performancein some reactions. The specific researeches included five aspects as follows.First, two kinds of montmorillonites from Inner Mongolia Province and ZhejiangProvince, were used to synthesize SPC-NM and SPC-ZJ by IGT. The effect of the natureof basic clays on their structure and properties were systematically investigated. Resultsindicate that two SPCs have order gallery mesoporous structure and open slit-shaped pore. Both of them have excellent thermal stability, but SPC-ZJ shows worse hydrothermalstability than SPC-NM because there are part of montmorillonite delamination and theformation of some mesoporous SiO2formed out of gallery regions in the structure ofSPC-ZJ. Compared with SPC-NM, SPC-ZJ shows higher conversion in catalysis crackingof heavy oil, but lower selectivion of gasoline and worse reusability.Second, a facile method was developed to synthesize Fe-doped SPC (deneted asFe-SPC) with various content of Fe2O3. A mixture of ethanol and water was used as thesolvent, which improves the dispersion of Fe3+in silica sol and high content of Fe2O3(upto27.03wt.%). Then, the effects of additive amount of Fe3+on their structure andproperties were systematically investigated. The results indicate that, Fe-SPC has orderedmesoporous structure, which is related to the usage of Fe(NO3)3. Fe ions were incorporatedinto the SiO2framework as tetrahedral coordination, meanwhile octahedral Fe species orFe2O3were formed out of the framework. Fe-SPC has good hydrothermal stability but badthermal stability. All Fe-SPCs show excellent catalytic performance and reusability inoxidative desulfurizations of coking benzene and model oil, especially in the former.Third, as octahedral Fe species in Fe-SPC trend to agglomerate, a new method was setup to synthesize Fe-incorpated SPC (deneted as (Fe,Si)-PILC) with high concentration ofFe. Moreover, their structure and properties were systematically investigated. The resultsshow that all iron species are tetrahedrally coordinated with the gallery silica nano-pillarsand no octahedral Fe species or Fe2O3are formed out of the framework.(Fe,Si)-PILC has asimilar structure as SPC, but the porous structure of the former is different from the laterowing to the incorporation of Fe. However this change is less than that in above Fe-SPC.(Fe,Si)-PILC has outstanding hydrothermal stability (better than Fe-SPC) and thermalstability. They also show good catalytic performance and reuseablity in phenolhydroxylation, which is supposed to be very sensitive to the framework iron species.Forth, a new kind of TiO2pillared monmorillonite (denoted as Ti-PILC) wassynthesized under a non-acidic condition by the IGT method, which was different fromtraditonal method. Furthermore, the effect of surfactants on their structure and propertieswere systematically investigated. Ti-PILC has ordered gallery mesoporous structure, whichis similar as SPC. The used surfactant will affect the porous structure, especially foraverage pore size. Because intra-gallery TiO2pillar belongs to anatase, Ti-PILC showsgood catalytic performance and reuseablity in the photolysis of methylene blue. The reactivity is influenced by the usage of catalyst and porous structure.Finally, to overcome the bad catalytic activity under visable light of Ti-PILC, a newkind of N-doped Ti-PILC (denoted as (Ti,N)-PILC) was synthesized, and the effects ofnitrogen atom on their structure and properties were also investigated. The nitrogen dopingdoes not obviously change the structure of Ti-PILC, but the absorption of gallery TiO2tovisable light is enhanced, which makes (Ti,N)-PILC show some catalytic performance inthe photolysis of methylene blue under visable light.更多还原