共查询到19条相似文献,搜索用时 203 毫秒
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核壳结构纳米复合材料,即一层或多层的无机或有机材料借助某种相互作用力包覆在无机或有机颗粒的外表面所形成的具有核壳结构的纳米材料。核壳结构纳米复合材料可以改善外壳和内核的不足,提高材料的光、电、磁、催化等特性。根据核和壳层的不同可划分出多种分类,且制备方法多样。核与壳之间的相互作用促使核壳结构纳米复合材料呈现出多种优异的功能特性,广泛应用于诸多领域。在催化中,核壳结构纳米复合材料不但表现出良好的耐化学侵蚀特性还能有效减少纳米粒子的团聚、烧结等问题。该文综述了核壳型纳米复合材料的分类、制备方法及在催化领域中的应用,简单阐述了其形成机理,并对其未来发展方向进行了展望。 相似文献
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无机-无机纳米复合材料以其独特的光学、电学、催化性能和广泛的应用受到人们的关注,成为纳米材料领域的研究热点,本论文主要研究了核壳结构的二氧化硅/银复合材料的制备和性能。 相似文献
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核壳结构纳米复合材料因其独特的结构而呈现出诸多新奇的物理、化学特性,在催化、生物、医学、光、电、磁以及高性能机械材料等领域具有广阔的应用前景。其中核/壳型结构的催化剂不仅可实现可控催化反应,还可以保护芯材不受外界环境的化学侵蚀,解决纳米粒子的团聚等问题,成为近年来催化领域的研究热点。本文系统综述了核壳型纳米复合材料在催化中的最新研究进展,详细介绍了金属-金属、金属-氧化物、氧化物-氧化物等核壳结构型的纳米复合材料在燃料电池中的电催化氧化反应、有机物加氢、选择性氧化、还原、环境催化及光催化降解等反应中的应用,并对今后核壳结构型的催化剂的研究方向进行了展望。 相似文献
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蒙脱石是一种具有离子交换性的层状硅酸盐粘土矿物,利用其结构特性可以制备插层复合材料。这种通过插层反应得到的复合材料兼有无机主体和客体分子的性质,从而表现出不同于单一组分所具有的催化、吸附以及光、电、磁等性能,在构筑下一代的光学、光电纳米器件,化学或生物传感器,分子识别以及催化等领域存在潜在应用的价值。 相似文献
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《化学工业与工程技术》2021,(1):12-16
介绍了石墨烯、石墨烯复合材料及核壳型石墨烯金属纳米复合材料的性质及用途,分析了核壳型石墨烯金属纳米复合材料在小分子生物、电化学、催化、防腐、吸附、导热材料等领域的应用前景,综述了核壳结构的石墨烯金属纳米复合材料的研究进展、合成方法及应用机理,展望了核壳型石墨烯金属纳米复合材料在处理水体污染和电化学传感器检测领域的发展前景。 相似文献
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采用多种包覆方法制备的核壳纳米材料具有许多优于单一材料的性能,其独特的核壳结构可产生出色的协同作用和新特性,现在已经广泛用于催化、吸附、储能与转化、药物传递和光学等领域。在CO/CO2热催化加氢反应过程中,壳层包覆可对核体粒子表面进行修饰,如改变核体的表面电荷、官能团和反应特性等,从而提高核体的稳定性与分散性。核壳催化剂可形成封闭的内部微环境以富集反应物,提高反应速率和催化活性。部分核壳催化剂甚至还能实现接力催化,并提高体系内的能量利用率。主要介绍了核壳纳米材料的常用制备方法,不同类型壳层包覆的核壳催化剂在CO/CO2热催化加氢中的应用进展,并对该领域的未来发展进行了展望。 相似文献
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上转换荧光材料具有将近红外光转换为紫外光和可见光的光学性能,与传统的半导体材料复合,使其光谱响应拓展到近红外区域,充分利用太阳光,从而提高光催化效率。核壳结构除能够有效地防止核(上转换纳米材料)被污染失活外,还可以使其紧密接触,有利于荧光共振能量的传递,提高壳(半导体材料)对光的利用率。系统论述了上转换半导体核壳结构纳米复合材料的制备方法、催化降解效率和催化影响因素,对此类复合材料的结合和催化机理进行分析,指出今后应加强高效率荧光材料和催化活性更强的半导体材料复合及如何在实际中应用的研究。 相似文献
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甲烷干重整可以将两种温室气体(CO2和CH4)转化为合成气,传统负载型催化剂存在金属烧结、碳沉积的问题,导致失活。核壳结构催化剂具有空间限域效应,能有效解决以上问题。本文根据壳的种类,将核壳结构分为SiO2壳层、Al2O3壳层和其他壳层三类,并分别从制备方法、形貌结构、催化特性的角度介绍了研究现状。文中指出:氧化硅壳层的优势是制备简单,壳层易于调控,热稳定性高;Al2O3壳层能够提供碱性位点,增强CO2吸附与反应;CeO2壳层则可以提供氧空位,促进CO2活化和积炭的气化。据此,本文展望了核壳结构在未来的几个研究方向:对壳层材料的拓展与研究;对蛋黄壳、三明治等新型核壳结构的研究;精准调节核壳结构的形态并研究构效关系;大规模制备和工业应用等。 相似文献
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BACKGROUND: The synthesis of core–shell inorganic/polymer nanocomposites, in which the polymer shell determines the chemical properties and the interaction with the environment, whereas their physical properties are governed by both the size and shape of the inorganic core and the surrounding organic layer, is an area of increasing research activity. RESULTS: Core–shell and bead–string shaped attapulgite/poly(methyl methacrylate) (ATP/PMMA) nanocomposite particles were prepared by soapless emulsion polymerization in an aqueous suspension of attapulgite organically modified with cetyltrimethylammonium bromide. CONCLUSION: Transmission electron microscopy analysis results showed that the amounts of the monomer added had no influence on the morphologies of the ATP/PMMA particles. The morphologies only depended on the length/diameter ratio of the attapulgite fibrillar single crystal used. Long ATP needles formed the bead–string structure while short ATP needles formed the core–shell structure. Copyright © 2007 Society of Chemical Industry 相似文献
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《Journal of the European Ceramic Society》2017,37(6):2439-2447
Bi-layered zirconia rods of core-shell geometry with a porous core of different core porosities and a dense shell of various shell thicknesses were investigated. Core-shell structures were successfully prepared by thermoplastic co-extrusion of assembled feedrods. For comparison, non-layered rods with different porosities and tubes were also prepared. Mechanical properties of sintered core-shell rods were determined and compared with the properties of non-layered rods and tubes. Increasing porosity in the core of the core-shell rods decreased Young’s modulus and the dense shell improved the fracture resistance of the core-shell rods against bending loading. The fracture force of core-shell rods was in all cases considerably higher than the fracture force of non-layered porous rods or tubes with the same Young’s modulus. The fracture behaviour of core-shell rods and tubes was analysed and correlated with the calculated stress distribution in these structures. The principle of the core-shell concept was described and discussed. 相似文献
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Organic–inorganic hybrid nanocomposites are an emerging class of materials that hold significant promise due to their outstanding properties, which usually arise from a combined and/or synergistic effect of the properties of their organic and inorganic components. Despite the numerous functionalization methods described in literature, only a few of them allow precise and easy control of the chemical composition and structure of the organic shell, whereas this point is critical to control some of the nanohybrids properties such as solubility, specific interaction and so forth. In this context, reversible addition-fragmentation chain transfer polymerization/macromolecular design by interchange of xanthates (RAFT/MADIX) technology is a fantastic tool that can be easily performed in mild and “green” conditions, being compatible with a huge variety of functional monomers and providing an excellent control of the organic shell characteristics. This review aims to describe the state of the art of the use of RAFT/MADIX polymers for the preparation of these nanohybrids. After describing the most commonly used synthetic strategies for nanohybrids preparation, the main families of polymers are discussed in view of their chemical composition (homopolymer, copolymer, …) and/or the targeted properties (hydrophilic, hydrophobic, stimuli-responsive). The main advantages of RAFT/MADIX technology are discussed in terms of the numerous applications of those materials. 相似文献
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Core-shell structured materials are of special significance in various applications. Until now, most reported core-shell structures have polycrystalline or amorphous coatings as their shell layers, with popular morphologies of microspheres or quasi-spheres. However, the single crystals, either mesoscale or atomic ones, are still rarely reported as shell layers. If single crystals can be coated on core materials, it would result in a range of new type core-shell structures with various morphologies, and probably more potential applications. In this work, we demonstrate that periodic mesoporous organosilica (PMO) single crystals can partly grow on magnetic microspheres to form incomplete Fe(3)O(4)@nSiO(2)@PMO core-shell materials in aqueous solution, which indeed is the first illustration that mesoporous single-crystal materials can be used as shell layers for preparation of core-shell materials. The achieved materials have advantages of high specific surface areas, good magnetic responses, embedded functional groups and cubic mesopore channels, which might provide them with various application conveniences. We suppose the partial growth is largely decided by the competition between growing tendency of single crystals and the resistances to this tendency. In principle, other single crystals, including a range of atomic single crystals, such as zeolites, are able to be developed into such core-shell structures. 相似文献