共查询到19条相似文献,搜索用时 171 毫秒
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以环己烷为碳源、二茂铁为催化剂前躯,采用浮游催化法成功的在碳纤维表面生长了碳纳米管(CNT),制备了多尺度杂化材料CNTs/CF。实验重点考察了反应温度、二茂铁浓度、载气等参数对CNT在纤维表面生长的影响,通过扫描电镜(SEM)、投射电镜(TEM)研究了CNTs/CF的形貌及产物CNT的微观结构。当固定反应温度为820℃、二茂铁-环己烷浓度为2g/100mL时,随着氢气在载气中含量在0~100%范围内变化,产物CNT直径亦有86nm降低至39nm。通过单丝拉伸测试发现,相比初始碳纤维,不同长度的CNTs/CF单纤维强度下降幅度均在10%以内。 相似文献
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用竖式炉流动法,以二茂铁为催化剂,硫为助催化剂,苯为碳源制备碳纳米管(CNT),反应温度为1100-1200℃,碳纳米管的外径为20-40nm,内径10-30nm,长度5-20μm,并在2800℃对碳纳米管进行石墨化处理。用超声分散和溶液浇铸工艺制备碳纳米管,聚甲基丙烯酸甲酯(PMMA)/聚醋酸乙烯酯(PVAc)复合膜和石墨化碳纳米管/PMMA/PVAc复合膜,石墨化碳纳米管复合膜的导电性能明显优于碳纳米管复合膜,石墨化碳纳米管/PMMA/PVAc复合膜和碳纳米管/PMMA/PVAc复合膜的渗流阈值分别为2.5%和5%(质量分数),碳纳米管/PMMA/PVAc复合膜是很好的气敏候选材料。 相似文献
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不同基底上碳纳米管的制备及生长机理 总被引:2,自引:0,他引:2
以二茂铁为催化前驱物,C2H2为碳源,N2为载气,采用浮动催化法,在蓝宝石、单晶硅、石英、玻璃以及碳纤维基底上制备了不同形貌和结构的碳纳米管.利用扫描电子显微镜和Raman光谱对碳纳米管的形貌和微结构进行了表征.结果表明在蓝宝石和石英基底上所生长的碳纳米管薄膜具有较好的定向性和较高的石墨化程度;单晶硅基底上碳纳米管薄膜呈"底疏顶密"分布;而玻璃和碳纤维基底上所生长的碳纳米管不具有定向性.最后,对不同基底对碳纳米管生长的影响进行了分析和讨论. 相似文献
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M.R.Atiyah D.R.Awang Biak F.Ahmadun I.S.Ahamad F.Mohd Yasin H.Mohamed Yusoff 《材料科学技术学报》2011,(4):296-300
Synthesis of carbon nanotubes (CNTs) below 600℃ using supporting catalyst chemical vapor deposition method was reported by many research groups.However,the floating catalyst chemical vapor deposition received less attention due to imperfect nanotubes produced.In this work,the effects of varying the preheating temperature on the synthesis of CNT were investigated.The reaction temperature was set at 570℃.The preheating set temperature was varied from 150 to 400℃ at 50℃ interval.Three O-ring shape heating mantels were used as heating source for the preheater.In situ monitoring device was used to observe the temperature profile in the reactor.Benzene and ferrocene were used as the carbon source and catalyst precursor,respectively.Vertically aligned CNTs were synthesized when the preheating temperature was set at 400℃.When the preheating temperature was increased up to 400℃,both the length and the alignment of CNTs produced were improved. 相似文献
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Vertically aligned carbon nanotubes (VA-CNTs) with high purity have been grown on quartz substrate via the gas phase catalytic chemical vapour deposition (CVD) by using ferrocene as the catalyst source and camphor as the carbon source. The effects of catalyst concentration, flow rate and water assistance on the morphology and structure of VA-CNTs are investigated by SEM, TEM, Raman and XPS characterizations. Under the optimized CVD conditions with modest ferrocene concentration and flow rate, dense and well VA-CNT arrays have been obtained. The water concentration should be controlled to improve CNTs alignment and impurity without damaging the walls of CNTs. 相似文献
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Amanda Araújo Silva Romário Araújo Pinheiro Vladimir Jesus Trava-Airoldi Evaldo José Corat 《Fullerenes, Nanotubes and Carbon Nanostructures》2018,26(5):315-323
Multi-walled carbon nanotubes (MWCNTs) have been successfully grown by Chemical Vapor Deposition (CVD) method. Elucidating the key characteristics of catalyst sources that affect carbon nanotubes growth is of great importance for improving and control MWCNTs morphology and structure. In this work we present a systematically study of CVD parameters, such as catalyst source, substrate morphology and temperature and how it affects carbon nanotubes synthesis. The novelty of this work lies on the catalyst composition. Two specific catalyst sources were analyzed: (i) Fe2Co and (ii) Fe2Co with ferrocene. Cyclic Voltammetry results confirmed the presence of Fe2+ in the Fe2Co with ferrocene solution. X-Ray Diffraction analysis confirmed the presence of iron particles on the substrate surface after its submission to growth conditions. Raman results suggested an improvement in carbon nanotubes crystalline quality catalyzed by Fe2Co with ferrocene. For tridimensional substrates such as fibers, the Fe2Co with ferrocene provided aligned CNTs with lower defects density noticed in Raman spectra and SEM micrographs. Finally, we corroborated the Fe2+ encapsulation relation with the growth mechanism and MWCNTs formation. 相似文献
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The carbon nanotubes (CNTs) and CNTs doping with Fe based composites were rapid fabricated by gaseous detonation decomposition of oxygen, benzene and ferrocene mixed precursors. A series of novel experiments were designed to investigate the condensation and formation of carbon structural nanomaterials. The TEM, EDS, EDX, XRD and Raman characterizations provide fundamental evidence of the high yield and purity of the CNTs, CNTs doping with Fe composites during the gaseous detonation reaction process. The results showed that CNTs, CNTs with Fe based nanocrystals, spherical CCFNPs and their mixed products are with variant morphologies. The obtained CNTs is multi-walled carbon nanotubes and CNTs doping with a body-centered cubic iron or iron carbide cores, which can be obtained respectively through adjusting and controlling the detonation reaction environment and the precursors. 相似文献
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采用化学气相沉积(CVD)法在碳纤维(CF)表面原位生长碳纳米管(CNTs)。考察了不同催化剂、沉积温度、氢气流量以及样品距进气口距离等工艺参数对CNTs-CF生长的影响。利用SEM和高分辨透射电子显微镜(HRTEM)对CNTs-CF形貌和微结构进行了表征和分析。结果表明:在CF表面原位生长的CNTs为多壁结构,其中以Ni为催化剂得到的CNTs直径小、分布均匀;在600~750℃温度范围内,随着温度的升高,CNTs直径和长度减小,产量降低;随着氢气流量的增加,CNTs直径和长度均增加;距进气口30cm,在CF表面得到的CNTs覆盖率高、直径小且分布窄,有利于制备高质量CNTs。 相似文献
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《Journal of Experimental Nanoscience》2013,8(4):606-620
The jatropha-derived biodiesel, a green precursor was found to be a new and promising precursor for the synthesis of carbon nanotubes (CNTs) and carbon–nitrogen (C–N) nanotubes. The CNTs and C–N nanotubes have been synthesised by spray pyrolysis of biodiesel with ferrocene and ferrocene–acetonitrile, respectively, at elevated temperature under an argon atmosphere. The typical length and diameter of as-grown CNTs are 20?µm and 20–50?nm, respectively. The C–N nanotubes are found in bundles with effective length of ~30?µm and diameter ranging between 30 and 60?nm with bamboo-shaped morphology. The as-grown CNTs and C–N nanotubes were characterised through scanning and transmission electron microscopes, X-ray photoelectron, Raman and Fourier transform infrared spectroscopic techniques. These investigations revealed that the nanotubes synthesised by jatropha-derived biodiesel are clean from carbonaceous impurities and the bamboo compartment formations in C–N nanotubes are due to nitrogen incorporation. The nitrogen concentration in C–N nanotubes decreases with the increase in synthesis temperature. 相似文献
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碳源对碳纳米管形态的影响 总被引:7,自引:7,他引:0
以苯和甲苯为碳源,二茂铁为催化剂,含硫化合物为助催化剂,采用浮游催化裂解法制备了碳纳米管,并采用TEM对不同条件下所得碳纳米管进行了形态分析。结果发现,碳源中苯和甲苯的配比对碳纳米管的形态有着重要的影响。以纯苯为碳源时,产物主要为直线型碳纳米管,并存在极少量短的弯曲型碳纳米管。随着碳源中甲苯比例的增加,产物中折线型碳纳米管增加。以纯甲苯为碳源,产物中仍有少量直线型碳纳米管,而不完全是折线型碳纳米管;此外,产物中还发现了极少量分支型碳纳米管。根据所得结果讨论分析了甲苯的加入对碳纳米管形态的影响以及各种碳纳米管的形成机理,认为可能是由于甲苯在催化热解过程中产生的碳种不同于苯催化热解所产生的碳种,造成碳在催化剂颗粒各处浓度不同,从而在碳纳米管的不同部位引入五元环和七元环而形成各种形态的碳纳米管。 相似文献
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This study demonstrates the first example of the use of a metal-free catalyst for the continuous synthesis of carbon nanotubes (CNTs) by chemical vapor deposition (CVD). In this paper silica nanoparticles produced from the thermal decomposition of PSS-(2-(trans-3,4-Cyclohexanediol)ethyl)-Heptaisobutyl substituted (POSS) were used as catalyst and ethanol was served as both the solvent and the carbon source for nanotube growth. The POSS/ethanol solution was nebulized by an ultrasonic beam. The tiny mists were continuously introduced into the CVD reactor for the growth of CNTs. The morphology and structure of the CNTs have been investigated by scanning electron microscopy, high-resolution transmission electron microscopy, and Raman spectroscopy. The obtained CNTs have a multi-walled structure with diameters mainly in the size range from 13 to 16 nm. Detailed investigations on the growth conditions indicate that the growth temperature and POSS concentration are important for achieving high-quality nanotubes, and that the existing of small amount of water in ethanol is effective to remove amorphous carbon species during the formation of CNTs. The mass production of CNTs without any metal contaminant will provide a chance for investing and understanding the intrinsic properties of CNTs and applications particularly in nanoelectronics and biomedicines. 相似文献