碳纳米管薄膜热电发电机设计及耦合分析

为解决微小型器件电源体积大、质量重、集成难等问题,利用碳纳米管薄膜材料的热电特性,设计了一种新型的薄膜式热电发电机,可将热气流直接转化为电能。建立了薄膜热电发电机物理模型,研究了热电发电理论和控制方程,对碳纳米管薄膜热电发电单元进行有限元仿真,分析了输出电压和输出功率的变化规律。提出了减小内阻的方法,为改进碳纳米管薄膜热电发电实验模型提供理论依据。利用浮动催化化学气相沉积法制备了导电性较好的透明碳纳米管薄膜,其热电特性与仿真结果一致。碳纳米管薄膜柔韧性较好,将多个发电单元串联连接,构建圆柱体、截顶圆锥体等多种薄膜式热电发电机结构,易与微光机电系统集成,具有广阔的应用前景和实用价值。     

碳纳米管复合滤膜的表征及应用

在常温常压下,采用流涎法制得碳纳米管复合硝化纤维素滤膜并对其表征.以染料直接灰D为模型化合物.考察该滤膜对含苯环大分子染料的吸附过滤性能.实验表明,过滤效果较好,期望用于染料废水的处理.     

超疏水叠杯状碳纳米管薄膜的制备(英文)

采用化学气相沉积法制备了高纯度的叠杯状碳纳米管薄膜。生长15 min后,薄膜厚度可达～300μm。热重分析表明薄膜的纯度高达99.9%。透射电镜表征表明碳纳米管中石墨烯片层与轴向存在一定偏角呈叠杯状排列,其直径为80 nm～230 nm。通过对催化剂与叠杯状碳纳米管的结构分析,提出其根部生长机制。该叠杯状碳纳米管薄膜易于转移且具有良好的柔性。疏水性测试表明其具有超疏水表面,接触角约为155°,因而有望作为防水和自清洁保护层。     

Application of carbon nanotube in wireless sensor network to monitor carbon dioxide

Carbon nanotubes (CNTs) are allotropes of carbon with a cylindrical nanostructure. Over the years, new discoveries have led to new applications, often taking advantage of their unique electrical properties, extraordinary strength and efficiency in heat conduction. Since industrialisation, human activities have resulted in steadily increasing concentrations of the greenhouse gases. Excess amount of carbon dioxide (CO₂) in living environment is toxic and unsuitable for human consumption. Thus, a need exists for accurate, inexpensive, long-term monitoring of environmental contaminants using sensors that can be operated on site. Over the past decade, many wireless sensor network (WSN)-based monitoring applications have been proposed. This article reviews the developments of sensing elements to monitor CO₂ in the environment. The cylindrical carbon molecules have novel properties that make them potentially useful in many applications in nanotechnology, electronics, optics and other fields of materials science, as well as potential sensing element in wireless sensor technology. They exhibit extraordinary strength and unique electrical properties, and are efficient thermal conductors. The unique properties of CNT makes it a potential sensing element in the WSN technology.     

碳纳米管的表面修饰及其对碳纳米管/氟橡胶复合材料导电性能的影响

分别采用混酸和四氟化碳(CF4 ) 等离子体处理技术对碳纳米管(MWCNTs) 进行了表面修饰, 将处理前后的碳纳米管进行了XPS 和SEM 测试, 获得了处理后前的表面形貌和结构, 并采用溶液浇注的方式制备了MWCNTs/氟橡胶(FE) 复合材料, 探讨了不同碳纳米管状态(未处理、混酸处理、CF4等离子体处理) 的导电性能, 结果表明两种表面处理方式可以使MWCNTs 表面接上极性官能团。而且在相同的碳纳米管添加量下(质量分数分别为0. 1 %、0. 5 %、1. 0 %、2. 0 %) , 酸处理MWCNTs/ FE 的渗流阈值最小, 达0. 5 %。      

碳纳米管/聚合物复合材料界面结合性能的研究进展

碳纳米管(CNT)优异的力学性能使其成为复合材料优选的增强体。CNT/聚合物复合材料的力学性能主要受其界面结合性能的影响。综述了CNT/聚合物复合材料界面结合性能的研究方法和研究现状。对CNT/聚合物复合材料界面结合性能的研究,实验上采用微观表征技术、拉曼光谱分析技术和纳米力学拔出法,分子模拟方法则是通过对CNT施加位移或外力模拟CNT从聚合物基体中的抽拔过程。概述了聚合物的类型、晶态结构以及CNT的手性、功能化处理等因素对CNT/聚合物复合材料界面结合性能的影响,并展望了CNT/聚合物复合材料界面结合性能未来研究的重点方向。     

Photosensitized hydrogen evolution from water using a single-walled carbon nanotube/fullerodendron/SiO2 coaxial nanohybrid

A coaxial nanohybrid consisting of a single-walled carbon nanotube (SWCNT), fullerodendron, and SiO(2) shows high-efficiency light-driven hydrogen evolution from water. Upon visible light irradiation, SWCNT/fullerodendron/SiO(2) coaxial nanohybrid shows hydrogen evolution activity in the presence of methyl viologen (MV(2+)), benzyldihydronicotinamide (BNAH), and a colloidal polyvinyl alcohol(PVA)-Pt.     

电化学阻抗解析多壁碳纳米管/活性炭的电化学性能

以石油焦为原料化学活化制得活性炭(Activated carbon,AC),在此AC中加入不同量的多壁碳纳米管(Multi-walled carbon nanotubes,MWCNTs)作为超级电容器电极材料.依据交流阻抗谱中阻抗与电容关系,区分有效容量和内阻造成的能量损失,评价了超级电容器的性能.结果表明:加入质量分数3％～15％ MWCNTs的AC电极,实部电容高于纯AC电极,虚部电容则随着MWCNTs添加量的增加而显著降低.且其实部电容分数随MWCNTs加入量的增加呈上升趋势,虚部电容分数则随MWCNTs加入量增加而降低.在AC电极中加入MWCNTs,在降低电极内阻的同时可有效提高超级电容器的储能效率,并降低弛豫时间,提高其频率特性,改善电容行为.     

A kind of conical cup-stacked carbon nanotube

In this article, a kind of conical cup-stacked carbon nanotubes (CSCNTs) grown by the microwave irradiation of the mixture of ferrocene and carbon black nanoparticles is reported. They are characterized by the long-cone shape, the nearly unchanged wall thickness and the huge hollow core. SEM and TEM analyses reveal that they are formed by the stacking of the truncated conical graphene layers precipitated from the surfaces of catalysts. The motions and coalescences of catalysts result in the increase of catalyst size during reaction. At the same time, the inner diameter of the truncated conical graphite layer precipitated from the surface of catalyst can increase with the catalyst size continuously. As a result, the as-grown CSCNTs have the conical hollow core and almost unchanged wall thickness. To the best of our knowledge, this kind of conical CSCNTs has been reported for the first time.     

Encapsulation of fresh silicon nanocrystals in carbon nanotube cavity

An approach for filling the carbon nanotubes (CNTs) with silicon nanocrystals (Si-ncs) during the fragmentation process of silicon micrograins in de-ionized water is presented. An efficient fragmentation of homogenously aqueous dispersed micrograins and filling of the CNTs cavity with Si-ncs is demonstrated by nanosecond pulsed-laser irradiation. Direct laser ablation has a unique surface Si-ncs chemistry in water and following aqueous in-situ CNT cavity stabilization prevents pollution, agglomeration of Si-ncs and can lead to 1D nano-composite material.     

Stability and thermal conductivity enhancement of carbon nanotube nanofluid using gum arabic

This experimental study reports on the stability and thermal conductivity enhancement of carbon nanotubes (CNTs) nanofluids with and without gum arabic (GA). The stability of CNT in the presence of GA dispersant in water is systematically investigated by taking into account the combined effect of various parameters, such as sonication time, temperature, dispersant and particle concentration. The concentrations of CNT and GA have been varied from 0.01 to 0.1?wt% and from 0.25 to 5?wt%, respectively, and the sonication time has been varied in between 1 and 24?h. The stability of nanofluid is measured in terms of CNT concentration as a function of sediment time using UV-Vis spectrophotometer. Thermal conductivity of CNT nanofluids is measured using KD-2 prothermal conductivity meter from 25 to 60°C. Optimum GA concentration is obtained for the entire range of CNT concentration and 1–2.5?wt% of GA is found to be sufficient to stabilise all CNT range in water. Rapid sedimentation of CNTs is observed at higher GA concentration and sonication time. CNT in aqueous suspensions show strong tendency to aggregation and networking into clusters. Stability and thermal conductivity enhancement of CNT nanofluids have been presented to provide a heat transport medium capable of achieving high heat conductivity. Increase in CNT concentrations resulted in the non-linear thermal conductivity enhancement. More than 100–250% enhancement in thermal conductivity is observed for the range of CNT concentration and temperature.     

Hydrogen storage capacity of single-walled carbon nanotube prepared by a modified arc discharge

Single-walled carbon nanotubes (SWCNTs, the mean diameter of 1.35 nm) were produced by a modified arc discharging furnace using a mixture powder of KCl and Co-Ni alloy as catalyst at 600°C. The hydrogen storage capacity of SWCNTs was enhanced by the mechanism of atom hydrogen spillover from the supported catalyst. The temperature effect on the hydrogen storage capacity of as-grown SWCNTs was investigated. The relative experiments of SWCNT hydrogen uptake and release were carried out by a high-pressure volumetric gas-adsorption measurement system. The experimental results indicated that the hydrogen storage capacity of SWCNTs increased with the environmental temperatures decreasing. The hydrogen storage capacity of SWCNTs was up to 1.73 wt% at 77 K for 2 hours under the pressure of 10 MPa, and the corresponding releasing hydrogen capacity is about 1.23 wt% under ambient pressure.     

定向碳纳米管/炭纳米复合材料形貌和显微结构

以CVD法定向碳纳米管(ACNTs)阵列为骨架,利用化学气相渗透(CVI)工艺制备了新型定向碳纳米管/炭(ACNT/C)纳米复合材料。通过偏光金相显微镜(PLM)、扫描电子显微镜(SEM)、高分辨透射电子显微镜(HRTEM)、X射线衍射(XRD)和Raman光谱等分析方法对其显微结构和热解炭沉积机理进行了研究。结果表明:所制ACNT/C纳米复合材料的热解炭结构主要为类粗糙层结构,围绕碳纳米管生长的热解炭石墨层片结构清晰,并且碳纳米管和热解炭之间具有良好的界面结合;而在相同工艺条件下围绕炭纤维生长的热解炭为典型的光滑层结构。这可能是由于在热解炭沉积过程中存在碳纳米管"诱导"沉积过程,即沿着碳纳米管径向的离域化共轭π键和具有类似结构的芳香族大分子通过π-π非共价键作用相结合,并在CNTs纳米尺寸的影响下,芳香族大分子按照"软取向"(Softepitaxy)围绕碳纳米管生成环形层片状类石墨结构的热解炭。该研究结果有望为热解炭的可控沉积起到一定的借鉴作用。     

管径相关的多壁碳纳米管膜的压阻效应

利用三点弯曲法研究了不同管径的碳纳米管膜的压阻效应,实验结果表明,管径较小的碳纳米管膜与管径大的碳纳米管膜相比具有更显著的压阻效应,并对电阻随应力变化的机制作了详细的讨论.     

碳纳米管膜/电解液界面的整流效应

对碳纳米管(CNT)膜/电解液(电解质溶液)界面的整流效应进行了研究。实验所用的碳纳米管用热灯丝化学气相沉积法(CVD)合成,整流效应通过分析其伏安特性来研究。结果发现,在室温下与一定浓度的电解液中,碳纳米管膜/电解液界面呈现出较强的整流效应,且该效应随电解液温度和浓度的增大而增强,重点讨论了碳纳米管膜/电解液界面整流效应的产生机制。     

无氢化学气相沉积法制备碳纳米管

采用无氢的化学气相沉积法（CVD）进行碳纳米管的制备技术研究,并成功地制备了由20—φ80nm左右,长度为50-100μm左右的碳纳米管。通过改变气体的流量等影响因素实现了定向碳纳米管薄膜和多层碳纳米管薄膜以及其它各种形态的碳纳米管的制备。采用微区Raman光谱、扫描电子显微镜（SEM）和透射电子显微镜（TEM）等方法对产物的形貌和结构进行了表征,结果表明采用无氢CVD法可以制备出多种形态的碳纳米管。     

Infrared spectrometric evaluation of carbon nanotube sulfonation

In present study, wet chemical functionalization process of carbon nanotubes (CNT) is studied for evaluation of the structural and chemical changes in CNT. An aim of this research was to study the sulfonation process by a spectroscopic-chemometrics method. Purified multi wall carbon nanotubes (MWCNT) were activated being prepared via reaction with LiAlH₄ reducing agent, for nucleophilic attack by chlorosulfonic acid. In the next step, sulfonation was conducted by reflux. Fabricated samples were characterized by scanning electron microscope (SEM), thermo gravimetric analysis (TGA), Raman and Fourier transform infrared (FTIR) spectroscopy. In order to evaluate the reaction evolution trend, diffuse reflectance mid IR spectroscopy was employed to obtain data along the reaction period and spectral data were processed by multivariate curve resolution alternating least squares (MCR-ALS) chemometrics techniques.     

碳纳米管/聚乙烯咪唑纳米复合材料的制备与表征

采用化学改性手段制备了一类新型的碳纳米管／聚乙烯咪唑(CNTs／PVI)纳米复合材料。并通过红外光谱、扫描电镜、透射电镜和X射线衍射等手段表征CNTs／PVI产物。有机杂环聚合物引入碳纳米管材料体系以后,会显著改善碳纳米管在有机溶剂中的分散均匀性和可加工性,并将碳纳米管具有的优异力学、热稳定性能和杂环聚合物具有的优良溶解性等结合起来,得到一种新型的综合性能优异的光电功能材料。