乙醇火焰中的一维碳纳米材料及其生长机理研究

文章利用扫描电镜（SEM）、透射电镜（TEM）系统观察和研究了乙醇燃烧火焰中合成的具有各种不同形貌特征的一维碳纳米材料。观察发现燃烧产物中除了“空心”碳纳米管和平直“实心”碳纳米纤维以外,还包括锥状、单螺旋型、双螺旋型、带状、节状、疏松状、节状-螺旋混合型、平直-螺旋混合型等形貌特殊的一维碳纳米材料。研究认为影响它们生长的主要因素有：Fe和Ni元素与碳的亲和力的差异、基板预处理、火焰的宽区域和不稳定性等。对火焰中各种形貌一维碳纳米材料的生成机理和过程进行了分析和讨论。     

水热碳化法制备碳纳米材料

形态可控的碳纳米材料由于独特的结构和性能而受到研究者的普遍关注,常见的制备方法有化学气相沉积法(CVD)、乳液法和水热碳化法等。水热碳化法是一种重要的碳纳米材料制备方法,具有成本低、反应条件温和、产物粒径均匀且形态可控等特点。综述了近年来以糖类及淀粉等有机物为原料,采用水热碳化法制备各种形态可控碳纳米材料的研究现状,重点介绍了水热碳化工艺条件对合成碳微球、空心碳微球、核壳结构碳复合材料显微形貌的影响,并提出了水热碳化法制备碳纳米材料研究中存在的问题和今后可能的发展方向。     

一维纳米材料的ECR-CVD方法制备

应用电子回旋共振微波等离子体化学气相沉积方法(ECR-CVD)进行了一维纳米材料的制备.以Fe3O4纳米粒子为催化剂,采用不同的气源,在多孔硅基底上制备出了碳纳米管、掺硼碳纳米管以及异质结构的纳米管.利用扫描电子显微镜(SEM)、透射电子显微镜(TEM)和 X射线光电子谱(XPS)对样品的形貌、结构及组分进行表征.     

饲喂法制备碳纳米材料改性蚕丝的导热性能

将纳米石墨烯、单壁碳纳米管和纳米石墨粒子这三种碳纳米材料均匀涂覆在桑叶上饲喂四龄蚕,采用简易且绿色经济的饲喂法制备改性蚕丝.利用瞬态电热技术(TET)对蚕丝的导热性能进行研究结果表明:饲喂添加碳纳米材料的桑叶所得到的改性蚕丝的导热性能均有所降低,并且碳纳米材料的添加量越大,改性蚕丝的导热性能越低.导致改性蚕丝导热性能下...     

模板法制备一维聚合物纳米材料的研究进展

一维聚合物纳米材料具有特殊的结构和性能，在纳米器件、药物释放、纳米传感器等方面有应用前景。采用模板法可以制备结构可控、排列规整的一维聚合物纳米材料。通常选用具有纳米孔洞的多孔膜作模板，通过在模板孔洞中进行电化学或化学聚合，或将聚合物的溶液或熔体引入孔洞中进行制备。文中综述了近年来采用模板法制备一维聚合物纳米材料的研究进展。     

燃烧法制备氧化物纳米材料的研究进展

燃烧法是制备氧化物纳米材料的一种新方法，其中，气相燃烧法、燃烧火焰—化学气相凝聚法已经实现了工业化生产；而一些新的工艺方法，如低温燃烧合成法、喷雾燃烧法、电控火焰合成法在刺备纳米材料上也各有优缺点；燃烧法与其他技术的结合也在研究开发阶段。详细阐述了燃烧法的最新研究进展。     

直接氧化法制备准一维氧化物纳米材料的研究进展

准一维氧化物纳米材料因其独特的光学性能、电学性能及几何结构而成为当前纳米材料研究领域的热点和重点.论述了直接氧化法制备准一维氧化物纳米材料原理,着重介绍了这一方法在准一维氧化物纳米材料制备中的应用,并对其前景作了简要的展望.     

催化剂对乙醇催化燃烧法制备碳纳米纤维的影响

分别以硝酸铁、硝酸钴、硝酸镍以及氯化铁、氯化钴、氯化镍作为催化剂先体，利用乙醇催化燃烧法制备了碳纳米纤维。利用扫描电子显微术、透射电子显微术和X射线能量分散谱术对样品进行了表征。讨论了不同种类的催化剂先体对产物形貌和生长机制的影响。     

激光法制备碳质纳米材料

通过介绍在气体和液体介质中激光与固体材料相互作用的过程,评述了激光在不同介质中发生物理化学现象的差异.与气相中相比,激光冲蚀液体中固体材料产生的气态等离子区受到了液体限制,在该区域会产生更高的气态密度、温度和压力,适合于亚稳相纳米晶的合成.同时评述了激光制备碳基纳米材料的进展.激光在气相和液相中均可制得碳纳米管,气相中适于制备结构完整的碳纳米管,而液相中有利于纳米金刚石的合成.激光冲蚀液体中的石墨靶制备的纳米金刚石粒径较大,辐照石墨悬浮液工艺不仅可以获得超细的纳米金刚石还可以获得线型碳.激光法制备的碳基纳米材料具有尺寸小、纯度高和形状多样性,在未来有着广泛的潜在应用价值.     

火焰法沉积金刚石薄膜过程中碳在基底中的行为

采用火焰法在Ｍｏ基底上沉积金刚石薄膜，研究了在沉积过程中Ｃ在Ｍｏ基底中的行为，结果表明，在Ｍｏ基层上沉积金刚石时，碳原子与Ｍｏ反应形成Ｍｏ２Ｃ，随时间延长，Ｍｏ２Ｃ层加厚，Ｃ原子扩散进入基底的速率下降，之后Ｃ原子在Ｍｏ２Ｃ层表面达到过饱和开始金刚石形核。     

由煤或焦炭制备纳米碳质材料的新进展

评述了以煤为碳源制备富勒烯、纳米碳管、竹节形碳管、铁嵌入的纳米碳棒和由碳包覆的金属纳米粒子等各种纳米材料。认为：等离子体电孤放电法是由煤制备各种纳米碳质材料最常用的方法，随电弧条件及电极性质的不同，所制备的纳米碳质材料可有各种不同形态及结构、由于煤是分子固体而石墨是晶格固体，两种碳源的反应机理有明显不同。在等离子体电弧加热时，煤分解并产生许多具有简单芳烃结构的分子，在纳米碳质材料的形成过程中，这些分子可能作为纳米碳质材料的结构单元，同时原煤中的矿物质在合成过程中也起着重要作用，因此煤本身的性质对纳米材料的制备极为重要。煤是成本低廉且储量最丰富的碳源，将是大规模工业化生产纳米碳质材料最好的碳源之一。     

Hybrid carbon based nanomaterials for electrochemical detection of biomolecules

By combining different allotropic forms of carbon at the nanoscale it is possible to fabricate tailor made surfaces with unique properties. These novel materials have shown high potential especially in the electrochemical detection of different biomolecules, such as dopamine, glutamate and ascorbic acid, which are important neurotransmitters in the mammalian central nervous system. Thus, more information about their material properties must be obtained in order to realize their high potential to the maximum. The results presented in this review clearly point out that although there is an extensive amount of data available on the structural, chemical and electrochemical properties on different carbon nanoforms, the data are scattered, often inconsistent and even contradictory. Hybrid carbon nanomaterials are much less investigated than the individual allotropes, but based on the existing data they possess extremely interesting electrochemical properties. Thus, it is of utmost importance to carry out extensive step-by-step characterization of these materials by utilizing combination of detailed computational and experimental work. In this way it will become possible to avoid approaches to material design that are based solely on trial-and-error approach, which has, unfortunately, been more a rule than an exception.     

溶胶-凝胶法合成ZnO纳米材料及其抗菌性能研究

采用溶胶-凝胶法制备氧化锌纳米材料并考察了其抗菌性能.研究发现,通过调控醋酸锌-无水乙醇-氢氧化钠反应体系的反应温度、反应时间、反应物浓度以及反应体系中的水含量可以控制纳米ZnO的粒径分布;以金黄色葡萄球菌和大肠杆菌作为革兰氏阳性菌和革兰氏阴性菌的代表,用抑菌圈法考察了材料的抗菌性能,结果表明,溶胶-凝胶法合成的ZnO纳米材料抑菌效果明显优于相应的水热法产物和市售产品,且与其粒径分布密切相关;在实验条件下,ZnO材料对大肠杆菌和金黄色葡萄球菌的抑制性能随ZnO纳米材料的粒径增大在5nm左右出现一个极值,材料的粒径小于或大于5nm,其抗菌效果均变差.     

计算机技术在液化石油气密度和蒸汽压分析中的应用

本文介绍了液化石油气样品按SH/T0230—1992《液化石油气组成测定在(色谱法)》标准测定组成后(?)据GB/12576—1997《液化石油气蒸汽压和相对密度及辛烷值计算法》标准的算法,利用计算机技术对所测得液石油气的组成进行转换计算,继而快速准确计算出液化石油气的密度和蒸汽压。     

SiC一维、准一维纳米材料的制备工艺研究

综述了近年来SiC一维、准一维纳米材料制备工艺的最新研究进展,重点介绍了模板生长法、化学气相沉积法、熔体生长法、碳热还原法和溶胶-凝胶法的工艺特点,并对不同工艺方法制备的SiC一维、准一维纳米材料的微观形貌、优异性能进行了简要概述,总结了现阶段SiC一维、准一维纳米材料制备工艺研究所面临的问题及发展前景.     

Grafting the surface of carbon nanotubes and carbon black with the chemical properties of hyperbranched polyamines

Controlling the chemistry on the surface of new carbon materials is a key factor to widen the range of their applicability. In this paper we show a grafting methodology of polyalkylamines to the surface of carbon nanomaterials, in particular, carbon nanotubes and a carbon black. The aim of this work is to reach large degrees of covalent functionalization with hyperbranched polyethyleneimines (HBPEIs) and to efficiently preserve the strong chelating properties of the HBPEIs when they are fixed to the surface of these carbon materials. This functionalization opens new possibilities of using these carbon nanotubes-based hybrids. The results show that the HBPEIs are covalently attached to the carbon materials, forming hybrids. These hybrids emerge from the reaction of amine functions of the HBPEIs with carbonyls and carboxylic anhydrides of the carbon surface which become imine and imide bonds. Thus, due to the nature of these bonds, the pre-oxidized samples with relevant number of C=O groups showed an increase in the degree of functionalization with the HBPEIs. Furthermore, both the acid-base properties and the coordination capacity for metal ions of the hybrids are equivalent to that of the free HBPEIs in solution. This means that the chemical characteristics of the HBPEIs have been efficiently transferred to the hybrids. To reach this conclusion we have developed a novel procedure to assess the acid-base and the coordination properties of the hybrids (solids) by means of potentiometric titration. The good agreement of the values obtained for the hybrids and for the free HBPEIs in aqueous solution supports the reliability of the procedure. Moreover, the high capacity of the hybrids to capture Ni²⁺ by complexation opens new possibilities of using these hybrids to capture high-value metal ions such as Pd²⁺ and Pt²⁺.     

铬酸铅一维纳米材料的水热制备、表征及性能研究

利用水热法在不使用任何表面活性剂的情况下成功制备出了包括纳米棒、纳米线在内的铬酸铅一维纳米材料,通过改变反应温度可以很容易对铬酸铅一维纳米材料的长度和长径比进行调节。运用X射线粉末衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)和高分辨透射电镜(HRTEM)等对所得产物进行了系统的表征,同时对所制备的铬酸铅一维纳米材料的光学性质进行了研究分析。     

Low substrate temperature synthesis of carbon nanowalls by ultrasonic spray pyrolysis

In this paper, we report the synthesis of two-dimensional wall like carbon nanostructures (i.e. carbon nanowalls) by ultrasonic spray pyrolysis of ethanol and fullerene mixture. At higher temperature carbon nanofibers were formed on the substrate placed at the center of the reactor tube, whereas carbon nanowalls were observed on the substrate placed downstream of the tube below 100 °C. Spaces between the nanowalls changed with distance of the substrates from the furnace. Qualitative analysis of materials was performed using scanning electron microscopy, transmission electron microscopy and Raman spectroscopy.     

Influence of carbon nanomaterials on the properties of cement and concrete

Results of investigations of the influence of an addition of carbon nanomaterials to a cement paste on its properties, the morphological characteristics of the cement-hydration products, and the structure and strength of the concrete obtained on the basis of this paste are presented.     

One-step synthesis and characterization of carbon nanospheres via natural gas condensate pyrolysis

Abstract

In the current work, carbon nanospheres (CNSs) were prepared via pyrolysis of gas condensate in N₂ at 1273?K and atmospheric pressure for 2?h using ferric chloride as a catalyst precursor. X-ray diffraction, energy dispersive X-ray spectrometry (EDX) in scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectrometry (Raman), Fourier transform infrared spectroscopy, and thermal gravimetric analysis (TGA) are employed for the structural and morphological characterization of the nanomaterials formed. The conductivity of these films was measured using the four probe method. As results, SEM-EDX and TEM analysis reveal spherical shaped particles, with diameter varying between 100 and 200 nm and graphene interlayer distance of 0.339 nm. The very low I_D/I_G ratio obtained reveals a relatively low amount of disorder in the nanostructures and TGA analysis implies that thermal stability was achieved after 470?°C. Our work provides a simple synthetic strategy in one-step sample preparation of CNSs, which can be used for furfur applications such as high-performance supercapacitors or adsorbents.