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多壁碳纳米管表面均匀沉淀包覆四氧化三铁及其磁性能的研究 总被引:1,自引:0,他引:1
本文用均匀沉淀的方法在多壁碳纳米管表面包覆了四氧化三铁(Fe3O4),采用场发射扫描电镜(FESEM)和场发射透射电镜(FETEM)对改性多壁碳纳米管表面形貌进行观察,采用场发射透射电镜附带的X射线能谱仪(EDX)对其表面成分进行测试,同时结合X射线衍射仪(XRD)对多壁碳纳米管表面包覆的晶体结构进行分析,最后采用振动样品磁强计(VSM)和网络矢量分析仪表征了Fe3O4包覆多壁碳纳米管的静态磁性能和动态电磁性能.结果表明,均匀沉淀Fe3O4包覆多壁碳纳米管的效果理想,相对原始多壁碳纳米管,改性后的多壁碳纳米管静态磁性能有了显著提高,比饱和磁化强度为12.15 emu/g. 相似文献
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《化工新型材料》2017,(9)
采用化学气相沉积法(CVD)以酞菁铜(CuPc)为催化剂、甲烷为碳源在二氧化硅(SiO_2)基底上合成了碳纳米管薄膜(CNTs),经过扫描电镜(SEM)表征发现,合成的碳纳米管外径较大,范围约在140~280nm,长度约在10μm以上。拉曼光谱分析表明合成的碳纳米管为无定形(α-CNTs)结构。通过透射电镜(TEM)可以看出所制备α-CNTs管内中空,管壁厚度不均匀,约为20~100nm。采用二极管结构,在真空室中真空度为2×10-4 Pa时进行了场发射特性测试,测试结果表明SiO_2(α-CNTs)薄膜的场发射开启场强为1.05V/μm。通过计算得出薄膜的场增强因子为1.32×104,结果表明SiO_2(α-CNTs)具有良好的场发射特性。 相似文献
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氦气分压测量在检漏技术、液氦装置质量监控等方面具有重要的应用价值。基于气体吸附的碳纳米管场发射阴极小电流发射增强效应,开发了低压He压力传感技术。采用热化学气相沉积法(HCVD)在镍合金基底上制备了多壁碳纳米管(MWNT)薄膜样品,利用二极式结构对MWNT薄膜阴极的场发射与传感性能进行了研究。结果显示,在10-7~10-3Pa区间,部分样品的场发射电流随着真空系统He压力的升高而增大,呈现He压力传感效应。对大量样品的测试发现,晶体性差(ID/IG≥0.9)的MWNT薄膜阴极对He有强烈的传感特性。第一性原理研究表明:He吸附在MWNTs的缺陷部位后,电荷的转移以及聚集效应是MWNT薄膜阴极产生He压力传感效应的关键因素。该传感技术具有开发为微型氦气检漏与分压力测量器件的潜力。 相似文献
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本文利用在基板材料上涂敷镍盐作为催化剂前驱体,在火焰中成功制备出了碳纳米管材料。与前期的抛光和腐蚀法相比,该方法简化了催化剂的制备过程,碳纳米管合成的重复性和稳定性好,适合于大批量合成碳纳米管;采用场发射枪高分辨扫描电镜(SEM)、透射电镜(TEM)和激光拉曼光谱对碳纳米管的形貌进行了表征;研究了不同基板材料和燃料对碳纳米管形态的影响;讨论了碳纳米管的形成机理。认为涂敷镍盐而产生的高活性Ni催化剂是制备碳纳米管的主要因素。 相似文献
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以中国白杨树无烟煤为原料,添加一定量煤焦油和沥青黏结剂制成炭棒作为阳极,采用直流电弧法制备竹节状碳纳米管及炭纳米纤维.用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、能量散射谱(EDS)和X射线衍射(XRD)等技术对产物进行表征.结果表明:在较低氦气压力下(0.020MPa),采用不添加任何催化剂的无烟煤基炭棒进行电弧放电,在剩余阳极上制备得到竹节状碳纳米管和炭纳米纤维.所得竹节状碳纳米管多为开口状,直径在50nm左右;炭纳米纤维宏观上成绒毛球形,纤维的直径在30nm~50nm之间. 相似文献
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Hesabi ZR Allam NK Dahmen K Garmestani H A El-Sayed M 《ACS applied materials & interfaces》2011,3(4):952-955
In the present study, we report for the first time synthesis of TiO(2) nanotubes/CNTs heterojunction membrane. Chemical vapor deposition (CVD) of CNTs at 650 °C in a mixture of H(2)/He atmosphere led to in situ detachment of the anodically fabricated TiO(2) nanotube layers from the Ti substrate underneath. Morphological and structural evolution of TiO(2) nanotubes after CNTs deposition were investigated by field- emission scanning electron microscopy (FESEM), glancing angle X-ray diffraction (GAXRD), and X-ray photoelectron spectroscopy (XPS) analyses. 相似文献
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Seo JK Choi WS Kim HD Lee JH Choi EC Kim HJ Hong B 《Journal of nanoscience and nanotechnology》2011,11(12):11032-11036
We have investigated the direct growth of metal-free carbon nanotubes (CNTs) on glass substrates with microwave-plasma enhanced chemical vapor deposition (MPECVD). Amorphous carbon (a-C) films were used as a catalyst layer to grow metal-free CNTs. The a-C films were deposited on Corning glass substrates using RF magnetron sputtering with the use of a carbon target (99.99%) at room temperature. They were pretreated with hydrogen plasma using a microwave PECVD at 600 degrees C. Then, CNTs were prepared using microwave PECVD with a mixture of methane (CH4) and hydrogen (H2) gases. The CNTs were grown at different substrate temperatures (400 degrees C, 500 degrees C, and 600 degrees C) for 30 minutes. Other conditions were fixed. The growth trends of CNTs against substrate temperature were observed by field emission scanning electron microscopy (FE-SEM). The structure of a-C catalyst layer and grown CNTs were measured by Raman spectroscopy. High-resolution transmission electron microscopy (HR-TEM) images showed that the CNTs had bamboo-like multi-walled structures. Energy dispersive spectroscopy (EDS) measurements confirmed that the CNTs consisted of only carbon. 相似文献
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Silica nanotubes were synthesized using multi-walled carbon nanotubes (MWCNTs) as template. The as-obtained samples were characterized
by infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning
electron microscope (FE-SEM) and photoluminescent (PL) spectroscopy. The results indicate that the thickness of the outer
walls is about 10 nm and the inner diameter is completely dependent on the size of MWCNTs. The as-fabricated silica nanotubes
emit a strong violet light under excitation of 250 nm. 相似文献
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In present work, the effects of hydrogen and oxygen plasma treatments on the structural properties of carbon nanotubes (CNTs) synthesized by catalytic CVD (Chemical Vapor Deposition) have been systematically investigated. Field emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HRTEM), and Raman spectroscopy were used to characterize the microstructural changes of the CNTs. The oxygen plasma treatment resulted in that the nanoparticles were appeared at the surface of CNTs. At high r.f. power (300 Watt), the microstructure of CNT was changed from nanotube type to nano particles. Long plasma treatment time changed the CNT morphology dramatically. For hydrogen plasma, however, there was no change in microstructure of CNT From the Raman analysis, the crystallinity of CNT was deteriorated by the plasma treatment, regardless of plasma power, treatment time, and gas types. The CNTs treated in oxygen plasma for 90 min showed excellent dispersion properties in aqueous solution. 相似文献
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以酸处理的多壁碳纳米管(MWCNTs)为载体,采用水热合成法制备了InVO4/MWCNTs光催化剂.利用场发射扫描电镜、X射线粉末衍射、BET-N2吸附、傅里叶红外光谱和紫外-可见漫反射吸收光谱等技术对样品的形貌、晶相组成、比表面积和吸光性能等物理性质进行了表征,并以气相的苯作为模型污染物,研究催化剂样品在可见光(λ>420 nm)照射下的光催化氧化能力.结果表明,InVO4颗粒均匀附着于MWCNTs,表面粒径约100 nm.与纯InVO4相比,InVO4/MWCNTs的比表面积和可见光吸收性能显著提高.在可见光照射下,InVO4/MWCNTs具有良好的光催化活性,反应4 h光催化降解苯的转化率和矿化率分别为41.0%和43.4%,其转化率分别是InVO4的1.5倍和掺氮TiO2的3倍,InVO4/MWCNTs光催化活性的提高与载体MWCNTs良好的电子传输特性有关. 相似文献
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Xue Ren 《Materials Research Bulletin》2007,42(12):2202-2210
The helical carbon nanofibers (CNFs), synthesized at relatively low temperatures (lower than 250 °C) by using Cu as a catalyst, SiO2, TiO2, Al2O3, MgO as supports and acetylene as gas source, has been investigated.The products were characterized by field emission scanning electron microscope (FE-SEM), transmission electron microscope (TEM) and X-ray diffraction (XRD). The morphologies of obtained products influenced by the types of supports and weight ratios (Cu/support = 1:1, 1:5, and 1:10) were discussed. The average diameter of the helical CNFs was about 80 nm, and these CNFs had the same coil pitch, and coil diameter. 相似文献
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Hongdong Liu 《Journal of Materials Science: Materials in Electronics》2014,25(8):3353-3357
The carbon nanotubes (CNTs) anchored with SnO2 nanosheets were prepared using a hydrothermal method. The as-prepared products were characterized by X-ray diffraction, fourier transform infrared spectroscopy, thermogravimetric analyses, field emission scanning electron microscope and transmission electron microscope. The electrochemical performances of SnO2 nanosheets/CNTs composite were measured by galvanostatic charge/discharge cycling, cyclic voltammetry and electrochemical impedance spectroscopy. The results show that the SnO2 nanosheets/CNTs composite maintains high lithium storage capacity and good cycling stability. The designed structure plays key role in improving electrochemical performance. The CNTs anchored with SnO2 nanosheets will be an ideal candidate of anode material for lithium ion batteries. 相似文献
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Multiwall carbon nanotubes (MWCNTs) were grown by dielectric barrier discharge (DBD)-type plasma enhanced chemical vapor deposition (PECVD) method in downstream. The temperature was 973 K and the compositions of gases were methane, hydrogen and oxygen in the total pressure of 0.05 MPa. The effect of O2 concentration in the mixture on the configuration of carbon nanotubes (CNTs) was investigated in detail. Results from scanning electron microscope (SEM) and transmission electron microscope (TEM) showed that CNTs grown in CH4/H2 (38.6%/61.4%, volume) mixture have many defects and contained disordered graphitic materials. With the addition of appropriate amount of O2 (∼ 0.67%), high-purity CNTs could be obtained. However, no CNT, even no carbon matrix existed under the condition of an excessive oxygen concentration (> 1.0%, volume) in the mixture. In order to understand the role of O2 during CNTs growth, optical emission spectroscopy (OES) was in-situ employed and the results predicted that the improvement of CNTs quality in O2 addition was attributed to the effect of OH oxidation from the reaction of atomic oxygen with hydrogen in the plasma. 相似文献
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Large-scale highly aligned boron carbonitride (BCN) nanofibers with controllable orientations and chemical compositions were synthesized directly on nickel substrates from a gas mixture of N2, H2, CH4, and B2H6 by plasma-enhanced hot filament chemical vapor deposition. The morphology of the BCN nanofibers was examined by scanning electron microscopy, the microstructures were studied by high-resolution transmission electron microscopy, and the bonding states as well as chemical compositions were determined by electron energy loss spectroscopy. To our knowledge, this is the first report on the photoluminescent properties of BCN nanofibers that shows that they are interesting blue- and violet-light-emitting materials with tunable wavelengths. Further studies on field electron emission suggest that BCN nanofibers are also promising candidates for field emission sources. 相似文献
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采用混合溶剂的溶液法技术,对聚丙烯接枝马来酸酐(PP-g-MAH)包覆碳纳米管(MWNTs)与聚丙烯(PP)纳米复合材料的电学和力学性能进行了研究。PP-g-MAH包覆MWNTs在二甲苯溶液中呈现良好的分散性,红外结果表明,酸化碳纳米管后表面官能团如羟基、羧基与马来酸酐发生氢键作用。场发射扫描电镜(FESEM)也证明了PP-g-MAH修饰MWNTs在PP基体中分散良好,并且相容性也得到了明显改善。复合材料的拉伸强度和电导率都有较大的提高,其中导电性相比未处理碳管/聚丙烯提高了两个数量级。 相似文献