共查询到18条相似文献,搜索用时 118 毫秒
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用AFM研究阳极氧化铝的不稳定生长 总被引:9,自引:0,他引:9
用原子力显微镜(AFM)研究了多孔阳极氧化铝(AAO)模板的不稳定生长. 结果表明:AAO模板的不稳定生长导致了纳米孔道结构有序度的降低.在H3PO4溶液中生长的AAO模板孔道结构稳定性较差;而在H2C2O4溶液中生长的AAO模板稳定性依赖于氧化电压和电流密度,在低电压和电流密度下稳定性较好,高电压和电流密度下稳定性较差. 充分利用这种不稳定生长特性,通过控制AAO模板的阳极氧化条件,可得到具有分枝孔道结构的特殊模板,这为利用模板法制备各种Y形或T形纳米线、管提供了新的发展空间. 相似文献
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采用溶胶凝胶法合成的Ni-Mo双金属氧化物催化剂,用CVD法催化裂解甲烷从而大量制备高质量高纯度的成束多壁纳米碳管.实验结果表明,该催化剂具有很高的活性和催化效率.反应2 h后,制备的多壁纳米碳管的量可达到初始催化剂量的80倍以上.碳管的直径较均匀,在10~20 nm之间.随着反应时间的延长,制备的纳米碳管石墨化程度增加,反应1 h后,粗产品中纳米碳管的含量就超过了97%. 简单放大后,单炉每克催化剂可以在0.5 h内制得40 g以上多壁纳米碳管. 相似文献
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AAO模板法生长碳纳米管阵列及形成机理研究 总被引:3,自引:0,他引:3
采用阳极刻蚀法制备得到多孔氧化铝模板(AAO),通过在二茂铁苯溶液中浸润而后热解的方法,得到内壁附着纳米铁颗粒的AAO模板。用化学气相沉积(CVD)法在AAO模板孔内生长出两端开口的碳纳米管(CNTs)阵列。仅用盐酸浸泡就可除去CNTs表面上的催化剂颗粒,得到高纯的CNTs阵列。高分辨透射电镜(HRTEM)和拉曼图谱(Raman)表明CNTs具有很低的石墨化结构。通过对CNTs形貌和形成过程的剖析,认为AAO模板孔道的导向作用以及模板孔内壁催化剂铁颗粒大小分布不均是形成低石墨化碳纳米管的主要原因。 相似文献
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以硅胶负载的Co纳米颗粒为催化剂,在低流量的减压体系中通过化学气相沉积法制备了规则螺旋状的纳米碳管.通过TEM和HRTEM研究了螺旋碳管的形貌、尺度分布以及管身、曲面和节点处的晶型;讨论了催化剂制备中pH值对催化剂的尺寸、规则程度和存在形态以致对螺旋碳管产量、管径厚度以及螺旋管的相对比例的影响;此外,还分析了反应压力对碳管生长的影响. 相似文献
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利用Ag离子与Br离子之间的化学沉积作用在孔隙中充满明胶的阳极氧化铝(AAO)模板中制备了AgBr/AAO纳米介孔复合材料.材料选择性曝光后,利用原位显影液对其进行化学显影,在AAO模板中选择性得到Ag纳米线阵列.实验结果表明:Ag纳米线是连续的、致密的,且具有多晶结构,充满了曝光部分的模板孔隙.本文还对影响Ag纳米线选择性生长的因素进行了简单讨论. 相似文献
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Asymmetric end-functionalization of carbon nanotubes was achieved by sequentially floating a substrate-free aligned carbon nanotube film on two different photoreactive solutions with only one side of the nanotube film being contacted with the photoreactive solution and exposed to UV light each time. The resultant nanotubes with different chemical reagents attached onto their opposite tube-ends should be very useful for site-selective self-assembling of carbon nanotubes into many novel functional structures for various potential applications. 相似文献
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Formation of Na nanotubes inside the channels of anodic aluminium oxide (AAO) membranes has been achieved by decomposing NaH thermally on AAO. The as-produced material, Na@AAO, is applied as a reactive template to prepare other tubular materials. Reacting Na@AAO with gaseous C6Cl6 generates carbon nanotubes (ca. 250 nm, wall thickness of 20 nm, tube length of 60 microm) inside the AAO channels. Highly aligned bundles of nearly amorphous carbon nanotubes are isolated after AAO is removed. 相似文献
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We report on the formation of highly anisotropic nanotube composite materials, made by the attachment of gold nanoparticles to the surface of the single-walled carbon nanotubes, followed by preparation of an aligned composite film by compression in a Langmuir-Blodgett trough. The gold is attached in a one-step sonication procedure. The gold-modified nanotube material forms a stable suspension in toluene and has been characterized by atomic force and scanning force microscopy, energy-dispersive X-ray spectroscopy, and Raman spectroscopy. The aligned films have highly anisotropic electrical properties, with a factor of approximately 3000 difference in the conductivity between the aligned and perpendicular directions. 相似文献
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柱状结构阵列碳纳米管膜的超疏水性研究 总被引:14,自引:1,他引:13
浸润性是固体表面的重要性质之一 .决定固体表面的浸润性的两个主要因素中 ,化学性质是内因 ,而几何结构形貌也是不可缺少的重要因素 .通过改变固体表面的粗糙度可以改变其浸润性 [1~ 5] .通常 ,人们用水接触角的大小来衡量固体表面水的浸润性 ,水与固体表面的接触角大于 1 5 相似文献
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《Electrochemistry communications》2007,9(7):1677-1683
The influence of both nanotube orientation and length on the electrochemical properties of electrodes modified with single-walled carbon nanotubes was investigated. Gold electrodes were modified with either randomly dispersed or vertically aligned nanotubes to which ferrocenemethylamine was attached. Electron transfer kinetics were found to depend strongly on the orientation of the nanotube, with electron transfer between the gold electrode and the ferrocene moiety being 40 times slower through randomly dispersed nanotubes than through vertically aligned nanotubes. The difference is hypothesized to be due to electron transfer being more direct through a single tube than that with electrodes modified with randomly dispersed nanotubes. With the vertically aligned nanotubes the rate constant for electron transfer varied inversely with the mean length of the nanotubes. The results indicate there is an advantage in using aligned carbon nanotube arrays over randomly dispersed nanotubes for achieving efficient electron transfer to bound redox active species such as in the case of bioelectronic or photovoltaic devices. 相似文献
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Ji-cheng Zhang Yong-jian Tang Yong Yi Min-jie Zhou Kang-fu Ma Wei-dong Wu Chao-yang Wang Yan Zhao Bing-chi Luo Zhuo Wang 《化学物理学报(中文版)》2015,28(5):617-622
Vertically aligned multi-walled carbon nanotube arrays grown on quartz substrate are obtained by co-pyrolysis of xylene and ferrocene at 850 oC in a tube furnace. Raman spectroscopy and high resolution transmission electron microscopy measurements show that the single-walled carbon nanotubes are only present on top of vertically aligned multi-walled carbon nanotube arrays. It has been revealed that isolated single-walled carbon nanotubes are only present in those floating catalyst generated materials. It thus suggests that the single-walled carbon nanotubes here are also generated by floating catalyst. Vertically alignedcarbon nanotube arrays on the quartz substrate have shown good orientation and good graphitization. Meanwhile, to investigate the growth mechanism, two bi-layers carbon nan-otube films with di erent thickness have been synthesized and analyzed by Raman spectroscopy. The results show that the two-layer vertically aligned carbon nanotube films grow “bottom-up”. There are distinguished Raman scattering signals for the second layer itself, surface of the first layer, interface between the first and second layer, side wall and bottom surface. It indicates that the obtained carbon nanotubes follow the base-growth mechanism, and the single-walled carbon nanotubes grow from their base at the growth beginning when iron catalyst particles have small size. Those carbon nanotubes with few walls (typically <5 walls) have similar properties, which also agree with the base-growth mechanism. 相似文献
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Kirsten Prehn Rainer Adelung Martin Heinen Suzana P. Nunes Karl Schulte 《Journal of membrane science》2008
A new membrane electrode assembly set up for catalytic processes containing carbon nanotubes has been developed. The process includes the nanotube synthesis, sputter deposition of platinum as catalyst and the membrane casting. Aligned nanotube carpets were grown from toluene/ferrocene solutions and sputtered with platinum. Subsequently the assembly was investigated using cyclic voltammetry to confirm a sufficient catalyst activity. A procedure was developed to embed the carbon nanotubes doped with catalyst into SPEEK membranes, while preserving the aligned structure and keeping some surface area of the catalyst-doped nanotubes free of membrane material to allow for easy access to reactants. So far the best results were obtained using an aligned but somewhat loose nanotube structure and a deposition of 0.034 mg/cm2 Pt, forming a combination of small catalyst clusters and a thin film. The assemblies are optimized in respect to application in fuel cells and functional membranes. 相似文献