液化石油气燃烧火焰制备一维碳纳米材料

本文利用民用液化石油气为碳源,在经过预处理的低碳钢和含Ni合金钢等基板上成功地制备出“空心”碳纳米管(CNTs)和“实心”碳纳米纤维(CNFs)等一维碳纳米材料。实验发现基板预处理对一维碳纳米材料的制备起着决定性的作用,如：机械研磨预处理时很难制备出一维碳纳米材料,而采用涂覆和电镀处理则很容易获得一维碳纳米材料。利用场发射枪高分辨扫描电镜(SEM)、透射电镜(TEM)和激光拉曼光谱(RS)等技术对碳纳米材料的结构进行了表征。从本实验可以预见,制备一维碳纳米材料将变得更简单,更经济。     

影响催化燃烧法制备碳纳米材料的因素

讨论了基底在火焰中的位置、合成时间及火焰的稳定性等因素对乙醇催化燃烧法制备的产物的影响。采用乙醇作为碳源和燃料，在不同的制备条件下分别制备样品，并采用扫描电子显微镜、喇曼光谱等对样品进行表征。实验结果表明，基底在火焰中最佳位置为1.0-2.5cm，最佳的合成时间为5-30min，较高的火焰稳定性对于制备直径比较均匀、结构比较单一的碳纳米管和碳纳米纤维是有利的，而且能够提高产物石墨化程度，减少其结构缺陷。     

影响催化燃烧法制备碳纳米材料的因素

讨论了基底在火焰中的位置、合成时间及火焰的稳定性等因素对乙醇催化燃烧法制备的产物的影响。采用乙醇作为碳源和燃料,在不同的制备条件下分别制备样品,并采用扫描电子显微镜、喇曼光谱等对样品进行表征。实验结果表明,基底在火焰中最佳位置为1.0~2.5cm,最佳的合成时间为5~30min,较高的火焰稳定性对于制备直径比较均匀、结构比较单一的碳纳米管和碳纳米纤维是有利的,而且能够提高产物石墨化程度,减少其结构缺陷。     

影响催化燃烧法制备碳纳米材料的因素

讨论了基底在火焰中的位置、合成时间及火焰的稳定性等因素对乙醇催化燃烧法制备的产物的影响.采用乙醇作为碳源和燃料,在不同的制备条件下分别制备样品,并采用扫描电子显微镜、喇曼光谱等对样品进行表征.实验结果表明,基底在火焰中最佳位置为1.0～2.5 cm,最佳的合成时间为5～30 min,较高的火焰稳定性对于制备直径比较均匀、结构比较单一的碳纳米管和碳纳米纤维是有利的,而且能够提高产物石墨化程度,减少其结构缺陷.     

碳片组成的纳米薄膜材料显微结构研究

最近几年 ,碳纳米材料由于它在物理和化学方面的应用前景 ,引起了科学工作者们的广泛注意。这些材料包括碳纳米管[1] 、纳米线[2 ] 、Ｆｕｌｌｅｒｅｎｅｓ[3 ] 、纳米墙[4] 和纳米金刚石[5] 等。其中Ｆｕｌｌｅｒｅｎｅｓ和纳米金刚石被认为是零维材料 ,碳纳米管和纳米线是一维材料 ,纳米墙是二维材料。Ｗｕ[4] 等人在制备碳纳米管的过程中发现了纳米墙 ,并给出它的ＳＥＭ照片。但没有给出它的精细结构。我们在金刚石的制备过程中发现了一种由无序的碳片组成的纳米薄膜 ,并利用扫描电子显微镜 (ＳＥＭ)和高分辨电子显微镜 (ＨＲＥＭ)对它进…     

基于碳纳米材料构建传感器用于抗坏血酸、尿酸和多巴胺检测的研究进展

对应用于抗坏血酸、尿酸和多巴胺同时检测的碳纳米材料和电化学方法进行了简单阐述,重点从不同碳纳米材料的物理化学特性介绍了其在电化学传感器构建中发挥材料自身优势促进生物分子在传感器表面被灵敏准确识别的传感方法。总结了近年来基于石墨烯、碳纳米管、碳纳米纤维、纳米多孔碳和氮掺杂碳纳米材料等碳纳米材料构建传感器应用于三种生物分子同时检测的研究进展;分析了当前电化学传感器构建的不足及面临的挑战,并对今后电化学领域应用于生物活性分子快速检测的研究方向进行了展望。     

煤基碳纳米材料的研究进展

以煤基碳纳米管和煤基活性炭为代表,介绍了煤基碳纳米材料在生长机理、制备工艺和应用领域等方面的研究进展。提出研究开发煤基碳纳米管是实现低成本、大批量制备碳纳米管的重要途径;煤基活性炭在储能超级电容器中的使用拓展了其应用范围。     

液相法制备氧化镁晶须的SEM研究

氧化镁晶须 (熔点 30 73K)具有优良的耐热性、绝缘性、热传导性、补强性和很高的抗拉强度 ,很适合用做多种复合材料的增强剂。氧化镁晶须的制备方法大多采用气相法 ,工艺条件控制苛刻 ,生产成本高 ,大大限制了氧化镁晶须的工业生产与应用。本文以MgCl2 ·H2 O和NH3 ·H2 O为原料 ,借助纤维状碱式氯化镁中间体 ,运用“假象”技术获得了由纳米微粒烧结而成的氧化镁晶须状材料。利用SEM研究了制备条件对产物微观形态的影响。1　实验方法以精制卤水和氨水为原料 ,采用浓度适中的氯化镁溶液和较小的 [OH-] [Mg2 + ](0 15 ) ,控制反应温度…     

乙醇催化燃烧法制备Y形碳纳米纤维

介绍了一种既简单又经济的用于制备Y形结构碳纳米纤维的催化燃烧方法。采用乙醇作为碳源，金属盐溶液作为催化剂先体；同时，基底材料采用铜薄片；实验装置采用酒精灯。实验在常温常压下就可以进行，且不需要引入其他辅助生长Y形结的气体。实验结果表明，该方法具有一定的实用性，可实现大量制备；透射电镜分析结果表明，产物中所含Y形结结构丰富，如螺旋结构、非螺旋结构以及螺旋与非螺旋混合的结构。     

高温热解法制备碳螺线管的扫描电子显微镜研究

采用高温热解法,以乙炔为碳源,在金属催化剂和促进剂的作用下,大量制备碳螺线管.利用扫描电子显微镜对二重螺旋状碳纤维的形成和碳粒子纳米结构进行了观察研究,探讨螺旋生长机制.螺旋状生长的推动力是催化剂中间体的晶面的各向异性。本文还利用扫描电子显微镜表征其拉弹性。     

Fabrication of carbon nanomaterials by atmospheric pressure microplasma

Atmospheric pressure microplasma was produced in a scanning electron microscope (SEM) chamber for synthesising carbon nanomaterials. The SEM observation is convenient for both adjusting the gap length and observing the electrode surface before and after experiments. After adjusting the gap length, the electrodes were housed in a small removable gas cell equipped in the SEM chamber and CH₄ discharge gas was introduced into the gas cell. It was found that the discharge was pulsated automatically because of slow discharge through a large ballast resistor and fast discharge through gas breakdown, even though a DC voltage was applied. The peak pulse current density was almost 60 kA/cm², the peak power density in the microplasma volume was approximately 555 MW/cm³ and the pulse width was 10 ns typically. Spherical and nanotube-like carbon nanomaterials were found on the cathode surface after microplasma discharge for 1? 5 s.With the discharge time increasing, the spherical substance changes into nanotube-like carbon nanomaterials.     

Printable inorganic nanomaterials for flexible transparent electrodes: from synthesis to application

Printed and flexible electronics are definitely promising cutting-edge electronic technologies of the future.They offer a wide-variety of applications such as flexible circuits,flexible displays,flexible solar cells,skinlike pressure sensors,and radio frequency identification tags in our daily life.As the most-fundamental component of electronics,electrodes are made of conductive materials that play a key role in flexible and printed electronic devices.In this review,various inorganic conductive materials and strategies for obtaining highly conductive and uniform electrodes are demonstrated.Applications of printed electrodes fabricated via these strategies are also described.Nevertheless,there are a number of challenges yet to overcome to optimize the processing and performance of printed electrodes.     

Influence of catalyst supporters on catalyst nanoparticles in synthesis of single-walled carbon nanotubes

It is important to understand catalytic reactions involved in synthesizing carbon nanotubes. Usually, catalysts are used with supporters for better stability and influences of supporters on catalysis is negligible; however, catalysts used for synthesizing single-walled carbon nanotubes are too small to neglect their influence. Here, we experimentally investigated efficiencies of commonly used catalyst supporters such as magnesium oxide, zeolite, and aluminum oxide when they were combined with iron–cobalt, which is a typical catalyst. It was observed that zeolite-supported catalysts could synthesize single-walled carbon nanotubes, while the others could not. Cluster molecular orbital calculations showed that electronic states of catalysts supported by MgO in the boundary layer between catalysts and supporters were restricted due to covalent bonding between cobalt and magnesium. Density functional theory calculations indicated that catalysts on zeolite had enough electrical orbital near Fermi level and they widely spread over catalysts surface, but catalysts on MgO did not. This characteristic can affect catalytic activities.     

The applications of carbon nanomaterials in fiber-shaped energy storage devices

As a promising candidate for future demand,fiber-shaped electrochemical energy storage devices,such as supercapacitors and lithium-ion batteries have obtained considerable attention from academy to industry.Carbon nanomaterials,such as carbon nanotube and graphene,have been widely investigated as electrode materials due to their merits of light weight,flexibility and high capacitance.In this review,recent progress of carbon nanomaterials in flexible fiber-shaped energy storage devices has been summarized in accordance with the development of fibrous electrodes,including the diversified electrode preparation,functional and intelligent device structure,and large-scale production of fibrous electrodes or devices.     

碳纳米材料在导热聚合物复合材料中的应用

介绍了三种具有较高热导率的碳纳米材料:碳纳米管、纳米石墨片及纳米碳纤维的结构与导热性能,概述了三种碳纳米材料在改善聚合物复合材料导热性能方面的应用,重点分析了碳纳米材料的种类、用量、表面改性方法及复合材料的制备方法对聚合物复合材料热导率的影响,并对含碳纳米材料的导热聚合物复合材料未来的发展方向进行了分析与展望。     

蔗糖热解碳对LiFePO4材料结构和性能的影响

应用微波法制备了锂离子电池正极材料LiFePO4,通过预加在前驱体中的蔗糖受热分解产生的碳来改善材料的结构和性能。XRD和SEM分析发现,这种方式引进的碳对材料的晶体结构影响不大,但可抑制由于加热时间增加而引起的晶体长大。添加蔗糖材料的高倍率循环性能比纯LiFePO4大大提高。电化学阻抗谱显示,添加蔗糖的材料所装电池的阻抗可达123?,远小于纯LiFePO4材料的1110?。     

透射电镜下纳米材料的操纵

纳米材料以其不同于体材料的优异性能和广阔的应用前景成为材料和物理学研究的热点。纳米材料的性能与其结构密切相关，例如纳米碳管，可以表现为半导体性或金属性。传统的测量手段只能分别得到结构和性能的信息，无法满足纳米材料研究的需要，而且，作为未来电子器件的基本构成单元，纳米材料的原位操控和测量对纳米材料的性能研究和进一步构造新型电子器件也是非常有益和必要的。     

吸收对镜像对称一维光子晶体透射谱的影响

利用传输矩阵法理论,研究吸收对镜像对称结构一维光子晶体(ABCB)m(BCBA)m透射谱的影响。结果显示：各介质层吸收系数k的变化对光子晶体透射谱影响明显,其中B层介质的吸收对透射谱的影响最为强烈。具体表现为,当各层介质无吸收时,主禁带中出现一条透射率为100%的透射峰;随着B介质层系数k的增大,主禁带中透射峰的透射率迅速衰减,当k=0.001时,透射峰的透射率趋于0,而禁带两侧的通带透射率缓慢地趋于不完整的禁带;当A,B,C各层介质同时存在吸收时,透射峰及禁带两则通带的透射率急剧下降,k=0.0006时     

Copper induced synthesis of graphene using amorphous carbon

Copper is approaching its reliability limits with respect to electromigration due to very high current density as a result of continuous technology scaling. Graphene on the other hand has excellent electrical and thermal properties which can prove to be a vital candidate for improving the reliability performance of copper interconnections in ULSI. Possibility of crystallization of amorphous carbon into graphene catalyzed by copper thin film is demonstrated in this work, as evidenced by the Raman, XPS and SIMS analysis, and the number of graphene layer synthesized can be modified with the method developed. As the synthesized graphene layers are on top of the copper film whilst the amorphous carbon source is below the copper film, no contamination of the graphene layer is presence with the method developed, improving the quality and uniformity of the grown graphene layers.