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1.
边长为微米级的银纳米片的简易合成与形成机理 总被引:2,自引:0,他引:2
用低温(60 ℃)溶剂热法, 以N,N-二甲基甲酰胺(DMF)为主还原剂和溶剂, 以聚乙烯吡咯烷酮(PVP)为辅助还原剂和晶面生长控制剂, 以硝酸银为前驱物, 大量制备了高纯度的、边长为微米级、宽厚比≥10的单晶银纳米片. 采用粉末X射线衍射(PXRD)、场发射扫描电镜(FE-SEM)、透射电子显微镜(TEM)等表征和分析了合成产物的成分、形貌和结构. 结果表明, 合成的银纳米片为面心立方单晶, 边长为1-4 μm, 厚度为50-100 nm. 考察了不同溶剂对银纳米结构的影响, 并提出了大尺寸的银纳米片的形成机理. 本文为调控单晶银纳米片的边长和宽厚比提供了一种新的可靠的动力学方法, 制备的长边长、大宽厚比的单晶银纳米片在聚合物基导电复合材料和电磁屏蔽材料方面有潜在的重要应用. 相似文献
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用双还原法制备三角形银纳米片及其光学性能 总被引:6,自引:0,他引:6
在硼氢化钠和柠檬酸三钠共存的体系中还原硝酸银, 以聚乙烯吡咯烷酮(PVP)为表面活性剂和保护剂, 水浴加热制备得到三角形银纳米片, 用X射线衍射(XRD)、透射电子显微镜(TEM)、紫外-可见(UV-Vis)吸收光谱、表面增强拉曼散射(SERS)光谱对其进行了表征. 结果表明: 三角形银纳米片产物为立方相金属银, 边长为(100±40) nm, 厚度为(10±5) nm; 产物表现出与球形银纳米粒子完全不同的吸收光谱; 柠檬酸根在银晶核不同晶面的选择吸附、PVP的包覆作用及Ag(111)晶面的层错对产物的形成起决定作用; 与球形纳米颗粒相比, 三角形银纳米片膜对吡啶(Py)分子有显著的SERS活性. 相似文献
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以乙二醇为溶剂,采用溶剂热法合成出由纳米晶组装而成的Cu2ZnSnS4(CZTS)微球。采用X射线衍射仪(XRD)、拉曼光谱仪(Raman)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、紫外-可见漫反射光谱(DRS)对所得微球的结构与成分、颗粒大小与形貌和光学性质进行了测试分析。研究结果表明:溶剂热法制得的CZTS粉体具有四方晶相结构,微球由纳米晶组装而成,对可见光有良好的吸收;随着反应时间的增加,颗粒尺寸逐渐增大,且对形貌有一定影响;此外,文中还对CZTS微球的形成机理做了推测。 相似文献
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银纳米线的制备及电催化还原氧性能研究 总被引:1,自引:0,他引:1
分别以聚乙烯基吡咯烷酮(PVP),乙二醇作为软模板和还原剂,采用不同晶种(AgCl、Ag)快速合成了银纳米线.通过SEM和TEM表征,证明合成银纳米线材料形貌均一,颗粒含量很少.并且发现以AgCl为晶种合成的银纳米线长径比为200左右(SNWH),而以Ag为晶种合成的长径比为30左右(SNWL).以银纳米线作为电催化氧... 相似文献
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以银氨络离子为前躯体, 葡萄糖为还原剂, 在聚乙烯吡咯烷酮(PVP)和十二烷基硫酸钠(SDS)组成的软模板中反应, 首先得到形貌均一、粒径为(50±5) nm的纳米银颗粒, 随后自发生长成银纳米棒. 测试结果表明纳米银颗粒的等离子共振吸收峰在441 nm处, XRD表明其为面心立方体, 在(111)晶面有最强吸收|高分辨透射电镜(HRTEM)观察到的晶格条纹和孪晶面证实其为多重孪晶(MTP), 选区电子衍射(SAED)进一步证实了其具有五重孪晶结构. 由于孪晶结构具有很高的生长活性, 故推断上述孪晶纳米银颗粒经PVP-SDS软模板诱导, 在常温、水相且无需多元醇辅助的条件下, 仅通过受约束Ostwald熟化生长, 便可一锅法合成出各向异性的银纳米棒. 用该法替代高温有机相并加入晶种的多元醇方法, 提高了湿化学方法的实用性并可以显著降低制备一维银纳米材料的成本. 相似文献
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边长为微米级的银纳米片的简易合成与形成机理眄 总被引:1,自引:0,他引:1
用低温(60℃)溶剂热法,以N,N-二甲基甲酰胺(DMF)为主还原剂和溶剂,以聚乙烯吡咯烷酮(PVP)为辅助还原剂和晶面牛长控制剂,以硝酸银为前驱物,大量制备r高纯度的、边长为微米级、宽厚比≥10的单晶银纳米片.采用粉末X射线衍射(PXRD)、场发射扫描电镜(FE-SEM)、透射电子显微镜(TEM)等表征和分析了合成产物的成分、形貌和结构.结果表明,合成的银纳米片为面心立方单晶,边长为1-4μm,厚度为50-100nm.考察了不同溶剂对银纳米结构的影响,并提出了大尺寸的银纳米片的形成机理.本文为调控单晶银纳米片的边长和宽厚比提供了一种新的可靠的动力学方法,制备的长边长、大宽厚比的单晶银纳米片在聚合物基导电复合材料和电磁屏蔽材料方面有潜在的重要应用. 相似文献
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水溶性银纳米颗粒的制备及抗菌性能 总被引:4,自引:0,他引:4
采用液相还原法, 以单宁酸为还原剂, 聚乙烯吡咯烷酮(PVP)为修饰剂制备出了水溶性的表面修饰Ag纳米颗粒. 通过X 射线粉末衍射仪(XRD)、透射电子显微镜(TEM)、紫外-可见吸收分光光度计(UV-Vis)、傅里叶变换红外(FTIR)光谱仪等对所得样品的形貌和结构进行了表征. 采用肉汤稀释法测试了样品的抗菌性能, 考察了样品在水相中的分散稳定性, 提出了PVP修饰Ag纳米颗粒的形成机理. 结果表明所制备的样品具有Ag的面心立方晶体结构, 平均粒径为15-17 nm. 样品在水相中能长时间稳定分散; 对埃希氏大肠杆菌(E. coli)、金黄色葡萄球菌(S. aureus)具有明显的抗菌作用. 操作简便、条件温和的制备方法易于在工业规模上放大; 试剂无毒, 使得所制备的PVP修饰Ag纳米颗粒作为抗菌剂具有良好的应用前景. 相似文献
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Ravishankar Bhat Sharanabasava Ganachari Raghunandan Deshpande G. Ravindra A. Venkataraman 《Journal of Cluster Science》2013,24(1):107-114
In this research paper, we report on the rapid synthesis of silver nanoparticles using dried areca nut (Areca catechu). The microwave exposed aqueous areca nut powder when treated with the aqueous silver salt solution yielded irregular shaped silver nanoparticles. The formation and morphology of the nanoparticles are studied using UV–visible spectroscopy, field emission scanning electron microscopy, transmission electron microscopy and atomic force microscopy. The X-ray diffraction studies and energy dispersive X-ray analysis indicate that the particles are crystalline in nature. The understanding of capping of biological moiety is derived from Fourier transform infrared spectroscopy and the thermogravimetric analysis. The green chemistry approach for the synthesis of silver nanoparticles is modest, amenable for large scale commercial production. Further the biologically synthesized silver nanoparticles are known for their potential antibacterial activity. 相似文献
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Preparation of Silver Nanoparticles through Alcohol Reduction with Organoalkoxysilanes 总被引:1,自引:0,他引:1
Hoe Jin Hah Sang Man Koo Sang Hoon Lee 《Journal of Sol-Gel Science and Technology》2003,26(1-3):467-471
Silver nanoparticles of narrow size distribution were prepared through the chemical reduction in an alcohol solution with several organoalkoxysilanes. In this system, organoalkoxysilanes served as a stabilizer, protecting silver nanoparticles from aggregation. The changes in size and morphology of colloidal silver nanoparticles were investigated with the addition of organoalkoxysilanes such as 3-aminopropyltriethoxysilane (APS), methyltriethoxysilane (MTS), phenyltrimethoxysilane (PTS), vinyltriethoxysilane (VTS), and 3-glycidoxypropyltrimethoxysilane (GPS) as stabilizers. The organic functional groups of organoalkoxysilanes interact with silver ions and clusters, which stabilize silver nanoparticles in the system. The silver nanoparticles obtained were characterized with transmission electron microscopy (TEM), UV-vis spectroscopy, etc. 相似文献
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Jia H Xu W An J Li D Zhao B 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2006,64(4):956-960
We describe a simple method to synthesize triangular silver nanoparticles by photoreducing the silver ions by citrate. A noteworthy difference of the present method as compared with the previous photo-induced methods is that good shape control over the nanoparticles can be realized in the absence of soft templates or polymer directing agents. The formation process of the silver nanoparticles was investigated by UV-vis spectroscopy and transmission electron microscopy (TEM). It was found that the concentration of reactant plays important role in the morphology control of produced silver nanoparticles. As one of the applications of these nanoparticles, they were used as surface-enhanced Raman scattering substrates and 1,4-bis[2-(4-pyridyl)ethenyl]-benzene (BVPP) was used as a Raman probe to evaluate the enhancement ability of the triangular silver nanoparticles. 相似文献
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An eco-friendly chemical reduction method was successfully used for the preparation of chitosan (CTS) composite films loaded with silver nanoparticles (AgNPs) by self assembly method using poly(ethylene glycol) as both reducing and stabilizing agent. UV-Vis spectra of the prepared chitosan loaded silver nanoparticles (CTSLAg) films reveal that full reduction of silver ions to silver nanoparticles takes place at 90 °C. The effect of reaction conditions on the silver nanoparticles formation was investigated using UV-Vis spectrophotometer. The morphology of the films was tested by scanning electron microscopy (SEM). The DSC curves showed that the CTSLAg film had a favorable compatibility and heat stability. AgNPs were confirmed by XRD and UV-Vis spectroscopy. The TEM findings revealed that the silver nanoparticles synthesized were spherical in shape with uniform dispersal, and by increasing CTS:PEG ratio larger silver nanoparticles could be obtained. The results of antibacterial study reveal that the prepared nanocomposite films exhibited potential inhibition. 相似文献
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O. V. Kristavchuk I. V. Nikiforov V. I. Kukushkin A. N. Nechaev P. Yu. Apel 《Colloid Journal》2017,79(5):637-646
Composite poly(ethylene terephthalate) track membranes containing immobilized silver nanoparticles with the aim of using them for surface-enhanced Raman scattering spectroscopy have been obtained and studied. A dispersion of negatively charged silver nanoparticles has been synthesizes by the method of pulsed electrical discharge between silver electrodes immersed in distilled water. To ensure the electrostatic deposition of nanoparticles onto the track membrane surface, it has been modified with polyethyleneimine. The composition and morphology of the surface of the obtained composite membranes have been studied by X-ray photoelectron spectroscopy and scanning electron microscopy. Aggregation of nanoparticles on the surface has been analyzed. The coefficient of Raman-scattering enhancement has been determined by the example of rhodamine 6G molecules adsorbed on a membrane with immobilized silver nanoparticles. 相似文献
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Marco Garza-Navarro Virgilio González Ubaldo Ortiz Elder De la Rosa 《Journal of solid state chemistry》2010,183(1):99-5508
In the present work is reported the use of the biopolymer chitosan as template for the preparation of magnetite and magnetite/silver core/shell nanoparticles systems, following a two step procedure of magnetite nanoparticles in situ precipitation and subsequent silver ions reduction. The crystalline and morphological characteristics of both magnetite and magnetite/silver core/shell nanoparticles systems were analyzed by high resolution transmission electron microscopy (HRTEM) and nanobeam diffraction patterns (NBD). The results of these studies corroborate the core/shell morphology and the crystalline structure of the magnetite core and the silver shell. Moreover, magnetization temperature dependent, M(T), measurements show an unusual diluted magnetic behavior attributed to the dilution of the magnetic ordering in the magnetite and magnetite/silver core/shell nanoparticles systems. 相似文献
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A. I. Bulavchenko P. S. Popovetskiy E. A. Maksimovskiy 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2013,87(10):1756-1761
Liquid concentrates of silver and gold nanoparticles with 1–2 M metal concentrations were isolated by electrophoresis in a capacitor-type cell from AOT reverse micellar solutions in n-decane. The electrophoretic concentrates and the starting micellar solutions were characterized by nonaqueous electrophoresis, transmission electron microscopy, photon correlation spectroscopy (dynamic light scattering), and spectrophotometry. The hydrodynamic diameter of silver and gold nanoparticles was 13.2 and 8.6 nm, respectively; the ζ-potential was 70 and 13 mV. The drying of the concentrates on glass and silicon substrates and subsequent treatment with a 30% solution of water in ethanol gave mirror conducting Ag, Au, Ag-Au, and Au/Ag films containing on the average 80% metal and 20 wt % AOT. The film structure, morphology, and composition were studied by scanning electron microscopy (SEM) and energy dispersion analysis (EDX). 相似文献
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M. Ider K. Abderrafi A. Eddahbi S. Ouaskit A. Kassiba 《Journal of Cluster Science》2017,28(3):1051-1069
Silver nanoparticles were synthesized by the reduction of the silver nitrate (AgNO3) using the latex copolymer in ethanol solution under microwave (MW) heating. The reaction parameters such as silver precursor concentration (from 0.005 to 0.1 g/l) and MW power (200–800 W) significantly affect the formation rate, shape, size and distribution of the silver nanoparticles. A significant reduction of irradiation time was observed when the MW energy is compared to conventional thermal reduction processes. The prepared silver nanoparticles show uniform and stable sizes from 5 to 11 nm, which can be stored at room temperature for approximately 12 months without any visible change. These peculiarities indicate that the latex copolymer is a good stabilizer for the silver nanoparticles. The optical properties, morphology, and crystalline structure of the silver-latex copolymer nanocomposites were characterized by the Ultraviolet–Visible spectroscopy, transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The study of the TEM images at high magnifications identified the silver nanoparticles as face-centered cubic (fcc) structure with spherical and hexagonal shapes. 相似文献
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维生素E绿色还原法制备银纳米粒子的研究 总被引:1,自引:0,他引:1
采用一种绿色还原法制备银纳米粒子,以维生素E为还原剂,淀粉为稳定剂,在液相中还原硫酸银,通过改变溶液的pH值和反应时间,得到不同粒径的黄色银纳米粒子,并分别采用透射电镜、红外光谱、紫外-可见吸收光谱、扫描电镜和电化学方法对银纳米粒子进行表征。结果表明:维生素E在溶液中被氧化生成苯醌,反应得到的银纳米粒子为球形,粒径为8~25 nm;在较强碱性条件下,得到的银纳米粒子尺寸较小,分布较均匀,其平均粒径约为10 nm;不同条件下生成的银溶胶分别在417、411、409、408 nm处出现紫外吸收峰,这些吸收峰均为银纳米粒子的表面共振吸收;生成的银纳米粒子具有很好的电化学性质,并对L-半胱氨酸的电化学反应显示了良好的催化活性。 相似文献