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1.
含铁粒子修饰碳纳米管的初步研究   总被引:2,自引:0,他引:2  
采用溶液浸渍法在氧化的碳纳米管上搭载铁离子,并研究了在高温下氮气和乙炔气氛中它的化学性质.在氮气氛中600 °C退火后,铁离子转化成Fe3O4纳米颗粒,并负载于碳纳米管上;当它与乙炔在同样温度下作用时,形成被石墨层包裹的Fe3C纳米晶,石墨层的包裹可以避免空气氧化.高分辨透射电镜观察证实,用铁离子修饰的碳纳米管是一种优异的前躯体,它能够通过简单的工艺处理,合成Fe3O4和Fe3C两种磁性纳米颗粒,且它们均是单晶体.  相似文献
2.
石墨烯纳米片电场增强因子的模拟计算与对比   总被引:1,自引:0,他引:1  
石墨烯纳米片特殊的一维刀口状尖端赋予了其优异的电子场发射性能,而电场增强因子β是评价场发射性能的最重要参数,主要采用测定F-N曲线的实验方法进行推算.建立了形状为矩形薄片+半圆圆柱的石墨烯纳米片模型,竖直立于平行平板二极管的阴极上,利用电子束模拟软件EBS(Electron BeamSimulation)模拟计算了场发射装置的两极间的电场分布,由此决定石墨烯纳米片尖端的电场增强系数.研究了高度和顶端曲率半径变化对石墨烯纳米片电场增强因子的影响,根据计算数值拟合了电场增强系数的经验公式,提供了受形状控制的电场增强因子的数值范围,还与同尺寸的碳纳米管进行了比较,证实了本文的模型和计算模拟方法有效、可信.  相似文献
3.
采用Hummers法和超声剥离制备了氧化石墨烯(GO)纳米片层分散液,再与萘系减水剂(NS)复合得到NS/GO复合材料.研究了NS/GO复合材料对水泥净浆流动性和水泥石抗压耐折强度的影响.研究结果表明,当NS/GO的掺量为4.8g/0.06g(每100g水泥)时,净浆流动度可以达到204mm,所得水泥石的抗压强度为65.4MPa,且耐折强度达到10.6MPa,分别比对照样品提高了29.3%和41.4%.SEM形貌结果表明,GO能够促使水泥水化反应形成致密的片层状结构.这些结果对于提高混凝土的抗压耐折强度,以及抗裂性和耐久性等具有重要的意义.  相似文献
4.
石墨烯增强铜基复合材料的研究现状   总被引:1,自引:0,他引:1  
石墨烯由于其独特的结构和优异的性能已成为目前金属基复合材料中最具吸引力的碳质材料增强体.本文系统报道了石墨烯增强铜基复合材料的分散方法和制备技术.总结了石墨烯的添加对复合材料性能的影响和其强化机理.同时也指出了石墨烯增强铜基复合材料研究存在的问题,并对其潜在应用进行了展望.  相似文献
5.
Exfoliated graphite oxide was prepared by an improved Hummers method and was then reduced to graphene with hydrazine in the presence of ammonium hydroxide.N2adsorption–desorption measurement showed that graphene so obtained had a specific surface area as high as 818 m2/g.Galvanostatic charge/discharge curves demonstrated that the as-prepared graphene exhibited a specific capacitance of 186.9 F/g at a current density of 0.1 A/g and that about 96%of the specific capacitance was retained after 2000 cycles at a current density of 5 A/g.  相似文献
6.
High-quality graphene coating was directly grown on stainless steel meshes via chemical vapor deposition process, during which the morphology of the stainless steel was transformed rugged. When the graphene-coated stainless steel meshes were applied as current collectors of supercapacitors, the changes of the appearance and the graphene coating improved the contact between stainless steel meshes and the active materials, thus benefiting the performance of the supercapacitors. Furthermore, this simple method can be used to prepare the enhanced current collectors for other energy storage devices.  相似文献
7.
A simple and effective method for the preparation of amphiphilic graphene (AG) is presented under an organic solvent-free synthetic condition. The synthetic route first involves a cyclization reaction between carboxylic groups on graphene oxide and the amino groups on 5,6-diaminopyrazine-2,3-dicarbonitrile, and subsequent reduction by hydrazine. Results of UV-vis spectroscopy, Fourier transformed infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA) and Raman spectroscopy have confirmed that the covalent functionalization of graphene can be achieved through the formation of imidazo[4,5-b]pyrazine on the graphene sheets. As a result, AG can be successfully dispersed in water and common organic solvents. This work successfully provides a facile and efficient way to fabricate AG and may extend the potential applications of graphene-based materials in nanoelectronic devices, polymer fillers and biological field.  相似文献
8.
Strong chemical interactions between the oxygen-containing functional groups on graphene oxide (GO) sheets and the ions of divalent metals were exploited for the softening of hard water. GO membranes were prepared and evaluated for their ability to absorb Ca2+ and Mg2+ ions. These GO membranes can effectively absorb Ca2+ ions from hard water; a 1 mg GO membrane can remove as much as 0.05 mg Ca2+ ions. These GO membranes can be regenerated and used repeatedly.  相似文献
9.
To achieve a dopamine(DA)response with high sensitivity and high signal-to-noise ratio(S/N)with a patch-clamp system,polypyrrole/graphene(PPy/GR)nanocomposites were steadily electrodeposited by an electrochemical method on a planar microelectrode array(pMEA)fabricated by a standard micromachining process.The electrodeposition process was carried out by chronopotentimetry measurement scanning from 0.1 to 0.8 C/cm2at the current of 2 mA;0.5 C/cm2was found to be optimal.The pMEA modified by PPy/GR at the 0.5 C/cm2exhibits remarkable properties;for instance,the standard deviation(SD)decreases from 8.4614×10-11to 5.62×10 11A,reduced by 33.52%,and the sensitivity increases from 2566.88 to 76114.65μAmMcm-2,29.65 times higher than the bare Pt(platinum).A good linear relationship between the current and DA concentration in the range of 0.30 to 61.71μm was obtained,with a correlation coefficient of 0.997.The sensor is meaningful for neuroscience research and the treatment of neurological diseases.  相似文献
10.
The nanocomposites of SnO2-CuO/graphene are synthesized via a two-step method.CuO nanorods are firstly uniformly loaded on the graphene nanosheets,and then SnO2 nanoparticles are coated on CuO nanorods.SnO2-CuO/graphene nanocomposites exhibit high cyclability and capacity as anode of Li-ion battery.After 30 cycles,the capacity can maintain at 584 mAh g-1 at0.1C rate(10 h per half cycle).The high performance can be ascribed to the synergistic effect among SnO2 nanoparticles,CuO nanorods and graphene nanosheets.The results manifest that the nanocomposites of SnO2-CuO/graphene are very suitable for Li-ion battery anodes.  相似文献
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