共查询到18条相似文献,搜索用时 78 毫秒
1.
2.
碳纳米管由于其独特的结构和优异的电学、光学、力学、热学等物理化学性能,在材料、电子器件、传感器、催化剂和能源等领域具有广泛的应用前景,但是如何低成本批量制备高品质的碳纳米管是实现碳纳米管大规模应用的关键。本文综述了近年来化学气相沉积法合成碳纳米管的研究进展,表明化学气相沉积法是大规模可控制备碳纳米管最有效的方法,并对其未来的发展方向进行了分析和展望。 相似文献
3.
4.
催化化学气相沉积法合成单壁纳米碳管的研究进展 总被引:1,自引:0,他引:1
介绍了合成单壁纳米碳管的三种主要方法,总结了国内外催化化学气相沉积法合成单壁纳米碳管的研究现状,着重介绍了催化剂对合成单壁纳米碳管影响的研究情况,并分析了反应工艺条件对合成单壁纳米碳管的影响. 相似文献
5.
6.
用硝酸铁作催化剂,乙炔作碳源气体,高纯氮气作稀释气体,在750℃下化学气相沉积生长了绳状纳米碳管,用高分辨扫描电镜观察了所得绳状纳米碳管的形貌.纳米碳管的直径为100~200nm,长度为10~20 μm.文中还提出了绳状纳米碳管的生长机理. 相似文献
7.
等离子体化学气相沉积法合成石英玻璃 总被引:1,自引:0,他引:1
用高频等离子体作为热源,采用化学气相沉积法合成了石英玻璃样品.实验分别使用02和空气作为等离子体电离气体和冷却保护气体,改变等离子体电离工作气体种类时,等离子体火焰长度和石英玻璃沉积温度变化较大,而灯具冷却保护气体的改变对等离子火焰长度和石英玻璃沉积温度的影响不大.当等离子体电离气体和灯具保护气体均为O2时,等离子体火焰长度为12cm,石英基体温度为1 300℃,当等离子体电离气体和灯具保护气体均为空气时,等离子体火焰长度可达24cm,石英基体温度升高到l 840℃,可确保气相沉积过程进行,合成的石英玻璃在波长190nm处光透过率达84%,羟基含量3.5×10-6,可达到全光谱透过的要求. 相似文献
8.
9.
10.
11.
Carbon nanotubes (CNTs) were deposited on various substrates namely untreated silicon and quartz, Fe-deposited silicon and quartz, HF-treated silicon, silicon nitride-deposited silicon, copper foil, and stainless steel mesh using thermal chemical vapor deposition technique. The optimum parameters for the growth and the microstructure of the synthesized CNTs on these substrates are described. The results show that the growth of CNTs is strongly influenced by the substrate used. Vertically aligned multi-walled CNTs were found on quartz, Fe-deposited silicon and quartz, untreated silicon, and on silicon nitride-deposited silicon substrates. On the other hand, spaghetti-type growth was observed on stainless steel mesh, and no CNT growth was observed on HF-treated silicon and copper. Silicon nitride-deposited silicon substrate proved to be a promising substrate for long vertically aligned CNTs of length 110–130 μm. We present a possible growth mechanism for vertically aligned and spaghetti-type growth of CNTs based on these results. 相似文献
12.
Tungsten oxide (WO3) nanorods array prepared using chemical vapor deposition techniques was studied. The influence of oxygen gas concentration
on the nanoscale tungsten oxide structure was observed; it was responsible for the stoichiometric and morphology variation
from nanoscale particle to nanorods array. Experimental results also indicated that the deposition temperature was highly
related to the morphology; the chemical structure, however, was stable. The evolution of the crystalline structure and surface
morphology was analyzed by scanning electron microscopy, Raman spectra and X-ray diffraction approaches. The stoichiometric
variation was indicated by energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. 相似文献
13.
14.
Randomly oriented short and low density conical carbon nanotubes (CNTs) were prepared on Si substrates by tubular microwave
plasma enhanced chemical vapor deposition process at relatively low temperature (350–550 °C) by judiciously controlling the
microwave power and growth time in C2H2 + NH3 gas composition and Fe catalyst. Both length as well as density of the CNTs increased with increasing microwave power. CNTs
consisted of regular conical compartments stacked in such a way that their outer diameter remained constant. Majority of the
nanotubes had a sharp conical tip (5–20 nm) while its other side was either open or had a cone/pear-shaped catalyst particle.
The CNTs were highly crystalline and had many open edges on the outer surface, particularly near the joints of the two compartments.
These films showed excellent field emission characteristics. The best emission was observed for a medium density film with
the lowest turn-on and threshold fields of 1.0 and 2.10 V/μm, respectively. It is suggested that not only CNT tip but open
edges on the body also act as active emission sites in the randomly oriented geometry of such periodic structures. 相似文献
15.
浓HNO_3通过沸点回流法对碳纳米管(Carbon Nanotubes,CNTs)进行处理,去除表面杂质并对CNTs切断开管,在开口处被修饰上羧基、羟基等基团。增加了碳纳米管(CNTs)在水及有机溶剂中的溶解性,另外通过湿化学法,在均相溶液中对碳纳米管(CNTs)包裹鲁米诺(Luminol)的实验条件也进行了优化,选择直径大的碳纳米管(CNTs)且溶解性较好的溶剂二甲亚砜(DMSO)。在检测方面采用Luminol-Co~(2+)-H_2O_2化学发光体系,对包裹鲁米诺(Luminol)的碳纳米管(CNTs)进行化学发光测试,该方法简单,灵敏。 相似文献
16.
17.
A temperature window for the synthesis of single-walled carbon nanotubes by catalytic chemical vapor deposition of CH4 over Mo2-Fe10/MgO catalyst has been studied by Raman spectroscopy. The results showed that when the temperature is lower than 750 °C, there
were few SWCNTs formed, and when the temperature is higher than 950 °C, mass amorphous carbons were formed in the SWCNTs bundles
due to the self-decomposition of CH4. The temperature window of SWCNTs efficient growth is between 800 and 950 °C, and the optimum growth temperature is about
900 °C. These results were supported by transmission electron microscope images of samples formed under different temperatures.
The temperature window is important for large-scale production of SWCNTs by catalytic chemical vapor deposition method. 相似文献