共查询到20条相似文献,搜索用时 15 毫秒
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Jayeeta Chattopadhyay Tara Sankar Pathak Daewon Pak Rohit Srivastava 《Korean Journal of Chemical Engineering》2016,33(5):1514-1529
Metal micro-/nano hollow spheres have been widely applied in numerous fields during the last decade. This review will only focus on the synthetic strategies to synthesize hollow spherical structures in the enhancement of their electrocatalytic activity, especially the metal hollow spherical materials. We present a comprehensive overview of synthetic strategies for metal hollow spherical structures which have been approached specifically in electrochemical reactions. These synthetic methods are mainly categorized as hard templates, soft templates, sacrificial templates and without templates. The review further includes electrocatalytic approaches of hollow spherical metals in different electrochemical processes, especially the methanol electro-oxidation reaction for methanol fuel cell application and hydrogen and oxygen evolution reactions in water electrolyzer, as metal hollow spherical materials are especially applied in these specific reactions. 相似文献
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Anatoly A. Zinchenko 《Polymer Science Series C》2012,54(1):80-87
During the past decade biomacromolecules attracted tremendous attention as versatile materials for self-assembly, nanoconstruction, and templating. An increasing number of reports highlights creative applications of DNA, proteins, and their assemblies for construction of materials, which synthesis by traditional top-down techniques is not possible. This review summarizes various aspects of the application of biomacromolecules and their self-organized structures for building-up inorganic nanomaterials of different complicity by metallization or mineralization of natural templates. The central focus of the review is given to DNA-templated and DNA-directed synthesis of nanostructures, as the progress in the utilization of DNA for nanoconstruction is most considerable. 相似文献
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Interest in creating tunable, ordered mesoporous materials based on surfactant supramolecular templating has been increasing over the last decade. For the production of film-type mesoporous materials, the most common method currently used is sol-gel based dip-coating method, which utilizes evaporation induced self-assembly (EISA) of surfactants. A more recently developed method, electrochemical interfacial surfactant templating, exploits the interfacial surfactant assembly formed on the working electrode to electrodeposit inorganic mesoporous films. This method offers mechanisms for inorganic wall construction and amphiphilic assemblies that are quite different from those of the sol-gel dip-coating method. As a result, it offers new possibilities to produce mesoporous films that cannot be produced by other means. This paper reviews the recent advances in producing and tuning lamellar structured mesoporous zinc oxide films via electrochemical interfacial surfactant templating. The general principles of this method will be explained in comparison with other methods used for producing mesoporous films. This will be followed by discussions of the key synthesis conditions that govern the repeat unit, quality, and orientation of lamellar structures constructed during electrodeposition. This review will provide a useful foundation to further develop electrochemical interfacial surfactant templating as a versatile method to produce a broader range of mesoporous films. 相似文献
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Using chitooligosaccharides (COS) as the backbones and polycaprolactones (PCL) as the branches, a novel type of amphiphilic graft copolymers with a large amount of free ? OH and ? NH2 groups remained on the COS backbones was synthesized. The obtained Chitooligosaccharide‐graft‐poly(ε‐caprolactone)(COS‐g‐PCL) was self‐assembled into giant vesicles which served as templates for the preparation of hollow spheres of a series of metals(Au, Ag, Cu, Pt, and Pd). The method involved the initial mixing of COS‐g‐PCL and metal‐containing groups or metal ions to generate corresponding complex, followed by adding the selective solvent of water to induce the self‐assembly of the graft copolymers into giant vesicles; Metal ions were reduced and crosslinked by a subsequent calcination procedure to form metal hollow spheres. In addition, hybrid hollow spheres with fluorescent quantum dots and silica hollow spheres were also prepared by slightly modified procedures. A preliminary study on the trinitrotoluene sensor of CdS/vesicle hybrid hollow spheres revealed a considerable sensitivity, which exemplifies the distinct properties imparted by the hybrid hollow structure. All of the results demonstrate that the giant vesicles self‐assembled from COS‐g‐PCL could be utilized as effective templates for the synthesis of various hollow spheres. Using Chitooligosaccharide‐graft‐poly(ε‐caprolactone) vesicles as general templates, the hollow spheres of a series of metals such as Au, Ag, Cu, and Pt were produced. The method involved the initial absorption of metal ions from solution into the functional surface layer of the graft copolymer giant vesicles. Metal ions were reduced and crosslinked by a subsequent calcination procedure to form metal hollow spheres. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 相似文献
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Rodriguez-Abreu C Vilanova N Solans C Ujihara M Imae T López-Quintela A Motojima S 《Nanoscale research letters》2011,6(1):330
Hollow silica microcoils have been prepared by using functionalized carbon microcoils as hard templates and surfactant or
amphiphilic dye aggregates as soft templates. The obtained materials have been characterized by electron and optical microscopy,
nitrogen sorption and small angle X-ray scattering. The obtained hollow microcoils resemble the original hard templates in
shape and size. Moreover, they have mesoporous walls (pore size ≈ 3 nm) with some domains where pores are ordered in a hexagonal
array, originated from surfactant micelles. The obtained silica microcoils also show preferential adsorption of cationic fluorescent
dyes. A mechanism for the formation of silica microcoils is proposed. 相似文献
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系统地总结了介孔沸石的合成方法,包括对合成的沸石分子筛的后处理、硬模板法和软模板法;并就制备方法和产品结构的特点进行了评述。后处理法包括对沸石分子筛的脱铝处理、脱硅处理及热处理;硬模板主要包括碳纳米粒子、介孔碳黑、碳纳米管、碳纳米纤维、碳气凝胶、有序介孔碳、胶体复制碳、无机纳米粒子等;软模板主要包括高分子聚合物和有机硅烷模板剂。 相似文献
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利用有机基质的模板作用能仿生合成出性能优异的新型无机材料。计算机模拟是研究有机基质自组装特性、超分子聚集体结构和特性的有效方法。本文简述了仿生技术的基础理论后,对两亲有机分子、有机高分子、生物大分子三类有机基质自组装的计算机模拟研究及其在仿生材料合成中的应用研究进行了综述,最后展望了仿生合成在未来材料化学中的发展趋势和前景。 相似文献
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This paper reviews the progress made recently in synthesis and applications of spherical silica micro/nanomaterials with multilevel (hierarchical) structures. The spherical silica micro/nanomaterials with hierarchical structures are classified into four main structural categories that include (1) hollow mesoporous spheres, (2) core-in-(hollow porous shell) spheres, (3) hollow spheres with multiple porous shells and (4) hierarchically porous spheres. Due to the complex structures and being focused on spherical silica micro/nanomaterials, some novel methods based on the combination of two routine methods or two surfactants, and some special synthetic strategies are proposed to produce the spherical silica micro/nanomaterials with hierarchical structures. Compared with the same-sized solid, porous or hollow silica spheres, these fantastic spherical silica micro/nanomaterials with hierarchical structures exhibit enhanced properties which may enable them to be used in broad and promising applications as ideal scaffolds (carriers) for biological, medical, and catalytic applications. 相似文献
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Structured carbon adsorbents from clay, zeolite and mesoporous aluminosilicate templates 总被引:2,自引:0,他引:2
Porous carbons templated from inorganic materials such as zeolites and mesoporous molecular sieves received considerable attention in the last decade. In this context, we discuss the effects of different templating structures on the carbons yielded. We describe templating using a commercial cationic clay (Wyoming bentonite), a commercial zeolite (Tosoh H-Beta) and a synthetic mesoporous aluminosilicate (Al-MCM-48), as exemplars of the categories of inorganic templates we have studied. The main carbon precursor used was furfuryl alcohol, complemented in some materials by an additional treatment using propylene carbon vapour deposition. The structures of the templates and carbons were compared using electron microscopy and powder X-ray diffraction. Carbons were further characterised with elemental analysis and nitrogen adsorption. The templating process is more complex than previously reported; the combination of these different techniques enhances the understanding of its mechanisms. A careful study of the synthesised carbons’ pore size distributions using DFT with various pore geometries was carried out and comparison with two commercial carbon adsorbents made, in order to assess the potential of such templated carbons for gas separation and gas storage. 相似文献
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自然环境中长期进化形成的多层次、多维和多尺度天然硬模板结构和一些具有多层次多维结构的天然“软”生物分子可为多级结构纳米材料的设计与制备提供了新的思路。金属氧化物通常作为催化剂的重要组成部分,其制备与催化应用得到广泛关注,生物模板法为金属氧化物的制备提供了一条简单、绿色、有效的合成路线。本文从基于生物模板的制备方法、生物模板在氧化物制备过程中的作用和生物模板在金属氧化物催化应用时的作用方面总结近十年来的研究进展。基于硬模板的制备方法简单高效,可完美地复制结构类似的金属氧化物材料,而软模板能够灵活地调控金属氧化物颗粒的尺寸和分散性。基于生物模板制备金属氧化物的过程往往经历“吸附-成核-生长-组装”多步骤,生物模板起着表面吸附、空间限域、导向等重要作用。就所得金属氧化物的催化应用而言,生物模板法的优势在于能够实现氧化物材料元素的自掺杂、有效改善传质以及特殊的表面结构赋予催化剂优异的催化性能。 相似文献
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Janus粒子是同一粒子中含有两种不同化学组成的非对称结构,其中两亲性Janus粒子是在对立面分别含有亲水基、疏水基两种不同化学基团,作为一种新型纳米材料受到广泛的关注。该文综述了模板法制备不对称结构的两亲性Janus粒子以及其应用领域,包括硬模板法、软模板法、牺牲模板法以及无模板法;综述了两亲性Janus粒子在表面活性剂、牙科粘合剂、微胶囊、功能涂层、催化剂以及生物传感器等方面的研究进展。 相似文献
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多孔液体是一类具有永久孔隙的新兴液体材料,它将多孔材料优异的性能和液体的流动性结合在一起。具有永久空腔的造孔器(pore generator),可以完全由无机砌块单元、有机配体和无机节点的组合单元或有机砌块单元构成。本文根据造孔器的结构综述了使用无机纳米材料、金属有机框架和多孔笼合成多孔液体的最新研究进展。文章指出作为新的研究领域,多孔液体化学正处于起步阶段,虽然面临着诸多挑战,但应用潜力巨大。目前在气体吸附、异构体识别、多孔液体膜的合成等方面都有研究,有望在气体捕捉和分离、催化、膜材料制备等领域得到应用。 相似文献
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In this study, hollow silica structures were synthesized by sol-gel/template technique using two types of hard templates: polystyrene-poly diallyldimethylammonium chloride (PS@PDADMAC) and polystyrene-polyethyleneimine (PS@PEI). The obtained templates were evaluated by zeta potential analysis, FTIR, SEM and EDX techniques. The obtained structures were then assessed by the TEM method. By controlling the ratio of the precursors, two morphologies were obtained: hollow spherical and hollow cubic. The results indicated the successful synthesis of two types of hollow silica spheres with the approximated diameters of 63 and 19 nm as well as two types of hollow cubic silica with approximated dimensions of 830 and 58 nm. SEM, XRD, and BET were used to further study morphology, phase composition, and porosity of the hollow silica spheres prepared by PS@PEI templates. 相似文献
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The use of protein templates to direct the formation of inorganic nanostructures offers a novel bio-inspired route to nanomaterial synthesis that avoids the use of harsh reaction conditions and offers unique functionalities including biocompatibility and hierarchical assembly. Pair distribution function (PDF) analysis from total X-ray scattering has been used to determine the structure of TiO2 nanoparticles grown within an icosahedral virus capsid. The protein-TiO2 composites are similar to nanocrystalline anatase and show photocatalytic activity. PDF analysis is ideally suited to the study of protein-inorganic nanocomposites, and may be able to provide information about the hard/soft interface. 相似文献
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铁氧体空心微球是一种特殊的新型材料,由于其具有特殊的空心结构而致使其具有许多独特的物理化学性质,有望发展成新一代的高效微波吸收剂。综述了国内外铁氧体空心微球的各种制备方法,如:喷雾热结法、模板法、逐层组装法等,及其优缺点和研究现状。 相似文献