共查询到19条相似文献,搜索用时 171 毫秒
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介孔材料由于其具有高度规则的孔径结构和一系列优良的物理化学性质,使其对复杂基质中选择性萃取低分子量蛋白质和多肽方面具有较大的优势和发展潜力。本研究采用共沉淀法结合后修饰法制备了一种介孔内表面修饰反相苯基基团、外表面修饰烷基二醇基的硅基介孔材料,并对其结构及选择性富集性能进行了考察。傅立叶变换红外光谱图表明,苯基和烷基二醇基成功修饰到介孔材料上;萃取实验结果表明,内外表面的双重修饰使其对标准蛋白、人血浆等复杂样品中低分子量蛋白质(分子量小于10 kDa)具有良好的富集选择性。 相似文献
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中空介孔材料,尤其是硅基和碳基中空介孔材料,由于其孔道结构丰富、孔径可调、高比表面积、可容纳客体分子、良好的热稳定性和化学稳定性等特点已被广泛应用于催化、能量储存等众多领域。模板法是目前为止制备中空介孔结构最有效的方法之一,其最大特点是可以通过对模板的调控来实现对中空介孔结构的控制。聚合物基模板种类繁多,主要包括嵌段共聚物、聚合物乳胶粒、天然/合成生物大分子及复杂结构高分子等;与传统的表面活性剂/无机氧化物模板相比,其自组装形态更加丰富,结构更易进行功能化修饰。同时,以聚合物为模板的合成反应条件更加温和可控,更有利于合成形态各异、功能丰富的中空介孔材料。本文综述了近年来不同聚合物基模板合成中空介孔材料的研究进展,并着重介绍了贵金属粒子负载的中空介孔材料在催化载体领域的应用;同时,指出了当前阻碍中空介孔材料发展的问题,并对其在催化领域的应用前景进行了展望。 相似文献
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介孔材料氨基表面修饰及其对CO2的吸附性能 总被引:15,自引:0,他引:15
采用接枝方法在介孔材料MCM-41和SBA-15的孔道内表面进行氨基化修饰, XRD、29Si-NMR、FT-IR、TGA、BET等测试结果表明, 氨丙基三乙氧基硅烷(APTS)和氨乙基氨丙基甲基二甲氧基硅烷(AEAPMDS)都分别接枝在介孔材料的孔道内, 表面氨基修饰量约为1.5-2.9 mmol·g-1. 表面修饰后介孔材料的孔道仍高度有序, 但比表面积减小. 表面修饰前后介孔材料对CO2的吸附性能发生显著变化, 由于物理吸附转化为以氨基为活性中心的化学吸附, 吸附量从修饰前的0.67 mmol·g-1提高到2.20 mmol·g-1. 相似文献
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基于杂多酸的固体高质子导体* 总被引:1,自引:0,他引:1
杂多酸固体高质子导体在燃料电池、传感器和电显色装置等方面具有潜在的应用前景。本文概述了杂多酸的质子导电性,归纳了其质子导电性的一些规律,以表格形式列举了各类杂多酸的电导率。将不同质量分数的杂多酸固载在各类固体基质上,可以对杂多酸质子导电材料改性以便于工业中实际应用。这些杂化材料兼有杂多酸的高质子导电性以及基质的稳定性与机械延展性。本文综述了近几年来新型杂多酸,杂多酸-无机基质复合材料,杂多酸-有机基质复合材料,杂多酸-多元基复合材料的质子电导率、稳定性、结构形态等等方面的研究进展,详细介绍了杂多酸在质子交换膜燃料电池中的应用,并对杂多酸固体高质子导体的应用前景进行了展望。 相似文献
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DSA电极电催化性能研究及尚待深入探究的几个问题 总被引:1,自引:0,他引:1
钛基氧化物涂层电极(DSA®)由于其对阳极析氯、阳极析氧、有机污染物电化学降解等具有优异的电催化活性而受到研究者的广泛关注,但DSA电极电催化现象背后的一些重要而基础性的问题仍未被人们完全认识。本文针对目前国内外有关DSA电极电催化研究领域中的几个研究热点、不足之处、以及尚待深入探究的问题,进行了简要介绍、分析和讨论。DSA电极的电催化活性主要是来自于其表面的金属氧化物涂层。本文强调对“氧化物涂层”自身固体物理-化学性能或过程的研究,有助于深入揭示钛基活性氧化物涂层电极电催化现象的微观作用机制和内在本质,并反过来指导人们更加理性地通过设计和优化DSA电极的制备方法和条件,调控表面氧化物涂层的化学组成与结构,进而达到增强钛基涂层电极电催化活性之目的。 相似文献
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M. T. Colomer 《Journal of Solid State Electrochemistry》2006,10(1):54-59
Nanoporous anatase xerogels were prepared via particulate sol–gel processes. The calcined xerogels were mesoporous, with a BET surface area of 121 m2/g, an average pore diameter of 5.8 nm and a pore volume of 0.236 cc/g. Proton conductivity of the membranes was measured as a function of temperature and relative humidity (RH). When anatase membranes are treated at pH 1.5, the proton conductivity increased in the whole range of temperature and RH. It indicates that the surface site density (number of water molecules per square nanometer) of these materials has a strong effect on conductivity. The proton conductivity of the studied anatase xerogels followed an Arrhenius-like dependence on the temperature (from room temperature to 90°C), in both treated and untreated membranes. A sigmoidal dependence of the conductivity on the RH was observed with the greatest increase noted between 58% and 81% RH in both treated and untreated anatase membranes. The highest value of proton conductivity was found to be 0.015 S/cm at 90°C and 81% RH, for treated anatase ceramic membranes. An increase in the conductivity could be achieved by means of longer times of treatment. According to the activation energy values, proton migration in this kind of materials could be dominated by the Grotthuss mechanism in the whole range of RH. The similar values of proton conductivity, lower cost and higher hydrophilicity of these membranes make them potential substitutes for perfluorosulfonic polymeric membranes in proton exchange membrane fuel cells (PEMFCs).
Presented at the conference Solid State Chemistry 2004, September 13–17, Prague, Czech Republic 相似文献
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The increase of the operation temperature in Proton Exchange Membrane Fuel Cells (PEMFC) above 100∘C would be an important breakthrough for the application of this type of fuel cell in electric vehicles. Hybrid organic-inorganic membranes with nano-sized interfaces can combine all the properties to meet this objective. Membranes using phenyltriethoxysilane and 3-methacryloxypropyl trimethoxysilane have been synthesised by polymerisation of methacrylate groups and inorganic condensation of silanol groups. Sulfonation process to provide proton conductivity affects both proton conductivity and chemical stability of hybrid membranes. Liquid sulfonation during the sol preparation and chlorosulfonic acid as sulfonating agent leads to chain cleavage while trimethylsilyl chlorosulfonate does not affect the polymer backbone. The increase of temperature (up to 120–130∘C) and relative humidity leads to an increase of proton conductivity close to 10− 3 S/cm. 相似文献
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硫酸交联壳聚糖膜质子传导行为的研究 总被引:1,自引:0,他引:1
制备了硫酸交联壳聚糖膜, 通过研究其质子传导性能、力学性能、化学成分及结构变化, 分析了硫酸与壳聚糖分子间的交联方式, 并对质子传导机理进行了解析. 结果表明, 硫酸交联可显著改善壳聚糖膜的质子传导能力与力学性能, 这种改善作用在交联6 h后趋于稳定, 交联6 h后的壳聚糖湿膜在室温下时质子传导率为0.0472 S• cm-1, 比未交联的壳聚糖膜提高5倍左右. 硫酸交联壳聚糖膜中的质子传导率与温度的关系符合Arrhenius定律, 质子传导激活能为18 kJ/mol, 其传导机制应属于Grotthus机制. 硫酸对提高壳聚糖膜的质子传导能力主要有两方面的作用: (1) H2SO4可使壳聚糖分子中NH2质子化形成NH3+. (2) 处于两个氨基之间的SO42-在质子传递过程中起离子桥梁作用, 参与以水分子为载体的质子传导过程, 从而减小质子传导的阻力, 提高了质子传导率. 相似文献
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碱处理PVDF膜对制备高电导率质子交换膜的作用 总被引:2,自引:1,他引:1
燃料电池是一种高能量密度、低污染的新型能源. 质子交换膜是燃料电池的核心组件之一. 在对聚偏氟乙烯(PVDF)膜进行了碱处理改性的基础上制备了高电导率的聚偏氟乙烯接枝聚苯乙烯磺酸(PVDF-g-PSSA)质子交换膜, 对碱处理后的PVDF膜进行了傅立叶变换红外光谱(FTIR)、傅立叶变换拉曼光谱(FT-Raman)及电子自旋共振(ESR)分析. 振动光谱显示在处理后的膜中存在共轭碳碳双键. 首次用ESR检测到碱处理后的PVDF膜中形成了自由基, 其浓度在1016 spin/g. 研究表明碱处理引起的膜结构变化有利于接枝反应的进行, 对提高所合成的质子交换膜的电导率有重要作用, 电导率提高一个数量级, 至6.40×10-2 S/cm. 相似文献
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Compared to internal combustion engines, proton-exchange membrane fuel cells (PEMFC) operate with zero emissions of environmental
pollutants being this an adequate choice for transportation field. The increase of the operation temperature of PEMFC above
130°C is a great concern for the commercial application of the cells in electric vehicles. Hybrid organic-inorganic nanostructured
membranes can combine the main properties to meet this objective: high proton conductivity along with thermal and chemical
stability. The possibilities of synthesis of these hybrid structures grow exponentially with the combination of sol-gel chemistry
and monomers. Three different approaches have been followed for obtaining hybrid membranes that present the properties needed
for application in high temperature PEMFC: development of methacrylate and epoxy structures, and optimization of the inorganic
component incorporating phosphorus. Proton conductivity has been endowed on the base of three strategies: a high concentration
of hydroxyl groups from inorganic component,
groups through sulfonation of phenyl rings, and incorporation of tungstophosphoric acid, H3[P(W3O10)4]. 相似文献
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Michaela Wilhelm Michael Jeske Roland Marschall Welchy Leite Cavalcanti Pia Tlle Christof Khler Dietmar Koch Thomas Frauenheim Georg Grathwohl Jürgen Caro Michael Wark 《Journal of membrane science》2008,316(1-2):164-175
For increased efficiency of high-temperature polymer electrolyte membrane fuel cells (HT-PEMFC), new types of membranes have to be developed. This approach has been realized by preparing hybrid membranes containing SO3H-functionalized mesoporous Si-MCM-41 as hydrophilic inorganic modifier in a polysiloxane matrix exhibiting sulfonic acid groups and basic heterocyclic groups like benzimidazole. The proton conductivity of sulfonated particles was modelled on the atomic scale in order to understand the influence of the density of sulfonic acid groups and of the presence of water molecules. The different hybrid membranes are characterized concerning their thermal stability, water uptake, and proton conductivity. Whereas the proton conductivity of well-established, but expensive and at >120 °C not long-time stable Nafion membranes continuously decreases with increasing temperature, the polysiloxane membranes, which suffer from a low-proton conductivity at around 100 °C, recover at about 120 °C due to intrinsic proton transport. At 180 °C the pure polysiloxane shows a proton conductivity which is only one order of magnitude lower than that of Nafion. Moreover, if the polysiloxane membrane contains additionally 10 wt.% of an SO3H-modified Si-MCM-41, the proton conductivity of such hybrid membrane at temperatures >180 °C and low relative humidity <10% is higher than that of Nafion membranes by a factor of 10. 相似文献
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胶体晶体模板法制备三维有序大孔复合氧化物* 总被引:1,自引:0,他引:1
胶体晶体模板法是制备三维有序大孔(3DOM)复合氧化物材料的有效方法。制备过程一般包括3个步骤:首先,将单分散微球堆积成三维有序排列的胶体晶体;其次,将液态前驱体填充到胶体晶体的间隙,并在原位转化为固体骨架;最后,将微球去除,在原来微球间的空隙位置得到固体骨架,原来微球占据的位置则成为相互连接的孔穴。其中,胶体晶体模板的组装、前驱体的填充以及模板的去除都是制备3DOM复合氧化物的关键影响因素。本文针对这几个控制因素对胶体晶体模板法制备3DOM复合氧化物的影响进行了概述,并对孔结构的表征以及材料在催化和电极材料等方面的应用作了简单介绍。 相似文献