共查询到20条相似文献,搜索用时 93 毫秒
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纳米金具有特殊的电催化性能。采用水/AOT(2-乙基己基琥珀酸酯磺酸钠)/环己烷微乳体系制备纳米金颗粒,通过改变水与AOT的物质的量比(ω)制备不同尺寸的纳米金,并通过透射电镜、紫外分光光度计、电化学工作站对纳米金颗粒的形貌尺寸、紫外吸收光谱、电化学性能进行分析与研究。结果表明,纳米金呈球形,尺寸均一,单分散性较好。通过对纳米金颗粒电催化析氢性能的测试发现,纳米金粒子分散性较好,形成的是均相溶液,纳米金粒子与Pt/C相比电催化性能稍弱,但是与纳米银、金铁合金和纳米硒化钨相比都显现出较好的电催化活性,说明纳米金粒子具有比较优良的电催化性能,为纳米金颗粒在生物电催化领域的应用奠定理论基础。 相似文献
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利用阳离子表面活性剂十六烷基三甲基溴化铵(CTAB)形成的反胶束作为微反应器合成了聚吡咯-氯化银(PPy/AgCl)纳米复合粒子.考察了吡咯/硝酸银、正己醇/水的比例的变化对PPy/AgCl纳米复合粒子的粒径大小和粒子形貌的影响,并利用TEM、SEM、FTIR、XRD和激光光散射粒度分析仪对产物进行了表征.结果显示,PPy/AgCl纳米粒子的粒径在40-60nm之间,改变合成条件可以进行自组装.FTIR和XRD显示复合物中含有PPy.因氯化银的存在,导致复合物的红外光谱向低波数方向移动.该实验结果同时表明,反胶束法可以有效地应用于有机/无机纳米复合粒子的制备. 相似文献
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微乳液法制备纳米羟基磷灰石的机理 总被引:10,自引:0,他引:10
采用二已基琥珀酰磺酸钠(aerosol OT,AOT)作为表面活性剂,正辛醇作为助表面活性剂,异辛烷为油相,将Ca(H2PO4)2·H2O水溶液和Ca(OH)2饱和溶液作为水相制成反相微乳液,并使两种微乳液反应,制备出呈单分散的球形纳米羟基磷灰石颗粒.通过系统性试验绘制了AOT/异辛烷/Ca(H2PO4)2·H2O水溶液和AOT/异辛烷/Ca(OH)2饱和溶液微乳液的局部三元拟相图,确定了该体系的反相微乳液单相区.采用动态激光散射原理分析了上述微乳液的胶束直径,确定了胶束直径与体系含水量的线性关系,并计算了微乳液胶束的有关参数.分析了羟基磷灰石的反应机理和颗粒的形成过程,并采用紫外可见光吸收光谱,研究了体系含水量对羟基磷灰石超细颗粒形成过程的影响. 相似文献
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壳聚糖氧化改性及还原稳定纳米银研究 总被引:2,自引:0,他引:2
利用简洁、环保、绿色的方法合成金属纳米粒子对于扩展纳米粒子在生物化学及组织工程中的应用具有重大意义。利用高碘酸钠对壳聚糖进行氧化反应制备双醛壳聚糖(D-CTS),用FT-IR、元素分析法对D-CTS进行表征,将制得的D-CTS作为还原剂和稳定剂制备纳米银粒子,最后用UV-Vis、DLS、FT-IR、XRD、SEM对制备的纳米银粒子进行表征。结果表明,D-CTS的氧化度和反应液的pH值对纳米粒子的粒径分布及微观结构有重要影响。D-CTS中的醛基和氨基是稳定纳米银粒子的主要基团。XRD分析制得的纳米银具有较好面心立体晶体结构,所制备的纳米银粒子粒径在30~40nm之间,同时常温条件下具有较好稳定性。 相似文献
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Stable water-dispersible silver nanoparticles with a narrow size distribution are obtained by light-assisted spontaneous reduction of silver nitrate with gelatin, which acts as both the reducing and the stabilizing agents, in water. The formation mechanism of the silver nanoparticles involves an in-situ conversion of Ag(+)-gelatin aggregates to gelatin-stabilized silver nanoparticles via a Ag(+)-mediated oxidation of primary amine groups of the gelatin to carboxylic acid groups. The resultant silver nanoparticles are well within the quantum size domain (10 nm). In addition, the nanoparticles are stable in aqueous solutions and can be separated easily by simple pH adjustment. 相似文献
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Kim MH Woo HG Lee BG Kim DH Yang KS Kim BH Park YJ Ko YC Roh SH Sohn H 《Journal of nanoscience and nanotechnology》2011,11(2):1593-1596
Silver nanoparticle/bis(o-phenolpropyl)silicone composites have been synthesized by the reduction of silver nitrate with bis(o-phenolpropyl)silicone BPPS [(o-phenolpropyl)2(SiMe2O)n, n = 2, 3, 8, 236]. TEM and FE-SEM data clearly show that the silver nanoparticles with the size of < 20 nm are well dispersed throughout the BPPS matrix in the composites. XRD patterns are consistent with those for multicrystalline silver. The size of silver nanoparticles increased with increasing the relative molar concentration of silver salts added. It was found that in the absence of BPPS, most of the silver nanoparticles undergo macroscopic precipitation by agglomeration, indicating that BPPS is essential to stabilize the silver nanoparticles. 相似文献
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Kim MH Kim DH Kim JH Woo HG Lee BG Yang KS Kim BH Park YJ Sohn H 《Journal of nanoscience and nanotechnology》2011,11(8):7374-7377
The formation of silver nanoparticle/bis(o-phenolpropyl)silicone composites have been promoted by the addition of chloroplatinic acid (<2 wt%) to the reaction of silver nitrate with bis(o-phenolpropyl)silicone BPPS [(o-phenolpropyl)2(SiMe2O)n, = 2, 3, 8, 236]. TEM and FE-SEM data exhibit that the silver nanoparticles having the size of <20 nm are well dispersed throughout the BPPS matrix in the composites. XRD patterns are consistent with those for polycrystalline silver. The addition of small amount of platinum to the silver accelerated the rate of composite formation by forming a Ag-Pt bimetallic alloy. The size of silver nanoparticles increased with increasing the relative molar concentration of silver salts added with respect to BPPS. However, the addition of platinum (1-5 wt%) to the AgNO3-BPPS mixture did not affect the size distribution of silver nanoparticles appreciably. It was found that in the absence of BPPS, most of the silver nanoparticles undergo macroscopic precipitation by agglomeration, indicating that BPPS is essential to stabilize the silver nanoparticles by coordination. 相似文献
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A seeding growth approach to the preparation of silver nanoparticles with a controllable size was developed. It contained a two-step reaction: the first step was gold seed clusters quickly generated by a chemical reaction using sodium borohydride as a reducing reagent; the second one was controllable silver nanoparticles were grown at the mild condition by using the mixed reducing reagents (hydroxylamine hydrochloride and sodium hydroxide) to form a buffer system. The gold core was beneficial for the crystalline of silver cations to form the nanoparticles and the buffer system which was composed of hydroxylamine hydrochloride and sodium hydroxide, and was helpful for controlling the size and shape of the as-prepared silver nanoparticles. These as-prepared nanoparticles were characterised by X-ray powder diffraction, UV-Vis spectroscopy (UV-Vis) and transmission electron microscopy along with energy dispersive X-ray spectroscopy. The results indicated that the obtained silver nanoparticles are highly crystallised with an average diameter around 10?nm. The content of gold seeds and the mild reaction rate controlled by the buffer system were considered to be key factors in the control of silver nanoparticles’ morphology and size. A possible mechanism of the silver nanoparticles formed was also proposed. 相似文献
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Adsorbed silver nanoparticles were prepared by means of electron beam evaporation of silver on ultra thin Si-supported heptadecafluoro-1-decene plasma polymer films and self-assembled heptadecafluorodecyl-trimethoxysilane monolayers. The morphology of the silver nanoparticles, characterized by their size, size distribution, shape and interparticle separation, was observed to depend on the type, chemical composition and surface energy of the sub-layer as well as the amount of silver deposited. Field emission-scanning electron microscopy was used to study the change in the morphology of the silver nanoparticles as a function of the preparation parameters. The silver nanoparticles on the ultra thin plasma polymer films demonstrated a much smaller and narrower size distribution due to the cross-linking within the film, which more effectively hinders the penetration of silver through the film in comparison to the self-assembled monolayers. Moreover, the optical properties of the resulting silver nanoparticles on the ultra thin fluorocarbon plasma polymers and their correlation to size and size distribution were investigated by spectroscopic ellipsometry in the wavelength range between 300 and 800?nm. 相似文献
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Quande Che Hongxing Yang Lin Lu Yuanhao Wang 《Journal of Materials Science: Materials in Electronics》2013,24(2):524-528
High-dispersive spherical silver nanoparticles were prepared by solvothemal process, using ethylene glycol as solvent and reducing agent. The silver nanoparticles were characterized by X-ray diffraction and FESEM to analyze the size, shape and morphology. X-Ray diffraction (XRD) pattern indicated that the silver nanoparticles were well-crystallized with no crystallographic impurities. The average size calculated by Debye–scherrer’s fomula was 48 nm, which well agreed with the result of FESEM. From the FESEM, it was demonstrated that the silver nanoparticles were high-dispersive and spherical in shape. Thick silver films were prepared by screen-printing using the front contact silver paste containing the as-prepared silver nanoparticles. The experimental results indicated that the silver nanoparticles were favor to sintering of micro-size silver particles, and contributed to improve the photovoltaic performances of crystalline silicon solar cells. 相似文献
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Zhang Xu Yang Peng Yang Wantai Chen Jinchun 《Materials science & engineering. C, Materials for biological applications》2008,28(2):237-242
Inspired by organic matrices in some life systems which can operate as templates for biosynthesis organic materials with uniform size and morphology, in our experiment, chitosan was combined with AG4 peptide (NPSSLFRYLPSD) to form a simple organic matrix, which was used as a template to synthesize particle size and morphology-controlling silver nanoparticles. The results of UV–vis determination and TEM observation indicated that uniform spherical silver nanoparticles with about 5 nm in size were obtained at the certain concentration of chitosan and silver ions. Hence, it is possible to control the size and morphology of silver nanoparticles at a certain extent by adjusting the concentration of chitosan and silver ions. In addition, triangle and hexagonal silver nanoparticles ranging from 20 nm to 60 nm in size appeared in different conditions. The advantage of this biomimetic synthesis of silver nanoparticles is that the process could be accomplished under mild conditions rather than stringent conditions, such as high temperature, very high pressures and a toxic environment, which usually occurs with the traditional methods for preparing metal nanoparticles. 相似文献
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Easier, less time consuming, green processes, which yield silver nanoparticles of uniform size, shape and morphology are of
interest. Various methods for synthesis, such as conventional temperature assisted process, controlled reaction at elevated
temperatures, and microwave assisted process have been evaluated for the kind of silver nanoparticles synthesized. Starch
has been employed as a template and reducing agent. Electron microscopy, photon correlation spectroscopy and surface plasmon
resonance have been employed to characterize the silver nanoparticles synthesized. Compared to conventional methods, microwave
assisted synthesis was faster and provided particles with an average particle size of 12 nm. Further, the starch functions
as template, preventing the aggregation of silver nanoparticles. 相似文献
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Silver nanoparticles of mean size 16 nm were synthesized by inert gas condensation (IGC) method. Crystalline structure, morphology and nanoparticles size estimation were conducted by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Antibacterial activity of these silver nanoparticles as a function of particles concentration against gram-negative bacterium Escherichia coli (E. coli) was carried out in liquid as well as solid growth media. Scanning electron microscopy (SEM) and TEM studies showed that silver nanoparticles after interaction with E.coli have adhered to and penetrated into the bacterial cells. Antibacterial properties of silver nanoparticles are attributed to their total surface area, as a larger surface to volume ratio of nanoparticles provides more efficient means for enhanced antibacterial activity. 相似文献