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Carbon Nanotubes Grown on Sepiolite as Catalyst Carrier 总被引:2,自引:0,他引:2
Multi-walled carbon nanotubes were synthesized by the catalytic decomposition of acetylene at 750℃ over sepiolite powder,which was treated with aqueous cobalt nitrate. It is expected that the composite with high specific area will have high capacity of hydrogen storage. 相似文献
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采用溶胶凝胶法合成的Ni-Mo双金属氧化物催化剂,用CVD法催化裂解甲烷从而大量制备高质量高纯度的成束多壁纳米碳管.实验结果表明,该催化剂具有很高的活性和催化效率.反应2 h后,制备的多壁纳米碳管的量可达到初始催化剂量的80倍以上.碳管的直径较均匀,在10~20 nm之间.随着反应时间的延长,制备的纳米碳管石墨化程度增加,反应1 h后,粗产品中纳米碳管的含量就超过了97%. 简单放大后,单炉每克催化剂可以在0.5 h内制得40 g以上多壁纳米碳管. 相似文献
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István Vesselényi Krisztian Niesz Andrea Siska Zoltán Kónya Klara Hernadi János B. Nagy Imre Kiricsi 《Reaction Kinetics and Catalysis Letters》2001,74(2):329-336
Multiwall carbon nanotubes have been prepared by catalytic chemical vapor deposition (CCVD) method in high yield using various metals supported on different supports. Measurements by transmission electron microscopy (TEM) revealed the presence of high quality nanotubes on each catalyst, however, comparing the different catalysts in nanotube production it can be stated that beyond metals, the support also affects both the quality and the quantity of nanotubes. 相似文献
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Dr. Molly Meng-Jung Li Dr. Hanbo Zou Dr. Jianwei Zheng Dr. Tai-Sing Wu Dr. Ting-Shan Chan Prof. Yun-Liang Soo Dr. Xin-Ping Wu Prof. Xue-Qing Gong Tianyi Chen Dr. Kanak Roy Prof. Georg Held Prof. Shik Chi Edman Tsang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(37):16173-16180
There is increasing interest in capturing H2 generated from renewables with CO2 to produce methanol. However, renewable hydrogen production is expensive and in limited quantity compared to CO2. Excess CO2 and limited H2 in the feedstock gas is not favorable for CO2 hydrogenation to methanol, causing low activity and poor methanol selectivity. Now, a class of Rh-In catalysts with optimal adsorption properties to the intermediates of methanol production is presented. The Rh-In catalyst can effectively catalyze methanol synthesis but inhibit the reverse water-gas shift reaction under H2-deficient gas flow and shows the best competitive methanol productivity under industrially applicable conditions in comparison with reported values. This work demonstrates a strong potential of Rh-In bimetallic composition, from which a convenient methanol synthesis based on flexible feedstock compositions (such as H2/CO2 from biomass derivatives) with lower energy cost can be established. 相似文献
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Branching carbon nanotubes were synthesized by pyrolysis of acetylene at 700℃ over oxygen-free copper and γ-Al2O3-supported Cu unitary or Cu/Fe binary catalysts. The morphologies of the as-grown products were charac-terized by transmission electron microscopy. The results indicated that the branching structures were closely related to the Cu component of the catalysts. We proposed that the special electronic structure (3d104s1) of Cu play the crucial role in the formation of the heptagon defects related to the branching structures. 相似文献
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Molly Meng‐Jung Li Hanbo Zou Jianwei Zheng Tai‐Sing Wu Ting‐Shan Chan Yun‐Liang Soo Xin‐Ping Wu Xue‐Qing Gong Tianyi Chen Kanak Roy Georg Held Shik Chi Edman Tsang 《Angewandte Chemie (International ed. in English)》2020,59(37):16039-16046
There is increasing interest in capturing H2 generated from renewables with CO2 to produce methanol. However, renewable hydrogen production is expensive and in limited quantity compared to CO2. Excess CO2 and limited H2 in the feedstock gas is not favorable for CO2 hydrogenation to methanol, causing low activity and poor methanol selectivity. Now, a class of Rh‐In catalysts with optimal adsorption properties to the intermediates of methanol production is presented. The Rh‐In catalyst can effectively catalyze methanol synthesis but inhibit the reverse water‐gas shift reaction under H2‐deficient gas flow and shows the best competitive methanol productivity under industrially applicable conditions in comparison with reported values. This work demonstrates a strong potential of Rh‐In bimetallic composition, from which a convenient methanol synthesis based on flexible feedstock compositions (such as H2/CO2 from biomass derivatives) with lower energy cost can be established. 相似文献
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Quasi-periodically intermittent hollow-cavity-stacked one-dimensional carbon nanostructures were obtained by microwave plasma chemical vapor deposition from the mixture of CH4 and N2 on Fe/γ-Al2O3 catalyst. This structure was characterized by transmission electron microscope (TEM), high-resolution TEM and X-ray energy dispersive spectral analysis. The results indicate that the trace impurity of nitrogen might account mainly for the formation of these novel nanostructures. The structural units in these one-dimensional carbon nanostructures are full of nanocavities, which may be of potential importance in hydrogen storage. 相似文献
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Chao Zheng Weizhong Qian Chaojie Cui Guanghui Xu Mengqiang Zhao Guili Tian Fei Wei 《天然气化学杂志》2012,(3):233-240
In this topic,we first discussed the requirement and performance of supercapacitors using carbon nanotubes(CNTs) as the electrode,including specific surface area,purity and cost.Then we reviewed the preparation technique of single walled CNTs(SWNTs) in relatively large scale by chemical vapor deposition method.Its catalysis on the decomposition of methane and other carbon source,the reactor type and the process control strategies were discussed.Special focus was concentrated on how to increase the yield,selectivity,and purity of SWNTs and how to inhibit the formation of impurities,including amorphous carbon,multiwalled CNTs and the carbon encapsulated metal particles,since these impurities seriously influenced the performance of SWNTs in supercapacitors.Wish it be helpful to further decrease its product cost and for the commercial use in supercapacitors. 相似文献
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微波等离子体化学气相沉积法低温制备直纳米碳管膜 总被引:7,自引:0,他引:7
Among the three main methods for the synthesis of carbon nanotubes (CNTs), chemical vapor deposition (CVD) has received a great deal of attention since CNTs can be synthesized at significantly low temperature. Plasma chemical vapor deposition methods can synthesize CNTs at lower temperature than thermal CVD. But in the usual catalytic growth of CNTs by CVD, CNTs are often tangled together and have some defects. These will limit the property research and potential applications. How to synthesize the straight CNTs at low temperature becomes a challenging issue. In this letter, straight carbon nanotube (CNT) films were achieved by microwave plasma chemical vapor deposition (MWPCVD) catalyzed by round Fe-Co-Ni alloy particles on Ni substrate at 610℃. It was found that, in our experimental condition, the uniform growth rate along the circumference of round alloy particles plays a very important role in the growth of straight CNT films. And because the substrate is conducting, the straight CNT films grown at low temperature may have the benefit for property research and offer the possibility to use them in the future applications. 相似文献
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Wooyong Seong Hyungwoo Hahm Seyong Kim Jongwoo Park Khalil A. Abboud Sukwon Hong 《Molecules (Basel, Switzerland)》2021,26(13)
Bimetallic bis-urea functionalized salen-aluminum catalysts have been developed for cyclic carbonate synthesis from epoxides and CO2. The urea moiety provides a bimetallic scaffold through hydrogen bonding, which expedites the cyclic carbonate formation reaction under mild reaction conditions. The turnover frequency (TOF) of the bis-urea salen Al catalyst is three times higher than that of a μ-oxo-bridged catalyst, and 13 times higher than that of a monomeric salen aluminum catalyst. The bimetallic reaction pathway is suggested based on urea additive studies and kinetic studies. Additionally, the X-ray crystal structure of a bis-urea salen Ni complex supports the self-assembly of the bis-urea salen metal complex through hydrogen bonding. 相似文献
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镍基板上低温合成定向纳米碳管 总被引:1,自引:0,他引:1
纳米碳管具有非常优异的场发射效应 ,亮度高、均匀且稳定的纳米碳管场效应发射器 ,例如平板显示器、阴极射线管以及信号灯等有着非常广阔的应用前景 [1] .由于纳米碳管的场发射效应与纳米碳管的方向性有关[2 ] ,因此定向纳米碳管的制备及其场发射性能研究是当前的一个研究热点 相似文献
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催化剂对纳米聚团床法制备的纳米碳材料形貌的影响 总被引:3,自引:0,他引:3
在纳米聚团床中用催化化学气相沉积法批量制备了碳纳米管,研\r\n究了过渡金属催化剂对碳纳米管形貌和产量的影响.实验结果表明,含\r\n铁催化剂的活性较低,产率较低,但产品质量较好;含镍催化剂的活性\r\n较高,产率较高,但产品质量较差;在钴催化剂作用下发现了一种新型\r\n的针状纳米碳材料.用含载体较少的铁催化剂可以得到纯度较高且微观\r\n结构较好的碳纳米管,但产率较低;不含任何载体的纯镍催化剂则不能\r\n得到碳纳米管.适宜的催化剂组成、催化剂活性点的均匀分布和裂解速\r\n度的控制等构成了纳米聚团床大批量制备碳纳米管技术的关键. 相似文献
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高聚物负载型双金属催化剂催化氢转移有机卤化物脱卤 总被引:16,自引:1,他引:16
以甲酸钠为氢转移试剂,以聚乙烯基吡咯烷酮负载PdCl2和其它金属盐制成双金属催化剂PVP-PdCl2-MXn,用于催化有机卤化物脱卤.与负载型单金属催化剂PVP-PdCl2相比,PVP-PdCl2-CdCl2和PVP-PdCl2-HgCl2对氯代芳烃脱氯有高得多的催化活性和脱氯选择性,且偶联副产物显著减少;以对氯苯胺为底物时,双金属催化下的反应时间缩短为单金属催化下的1/8,而脱氯产物收率提高25倍;底物为对氯甲苯时,双金属催化下的偶联副产物仅为单金属催化下的1/390.用IR和TEM技术对PVP负载型金属催化剂进行了表征,并讨论了双金属协同脱卤作用. 相似文献
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高温煅烧Mo改性的Fe/MgO催化剂用于制备管径分布均一的单壁碳纳米管 总被引:1,自引:0,他引:1
研究了在以甲烷化学气相沉积法制备单壁碳纳米管的过程中高温煅烧预处理(900℃煅烧10h)对Mo改性Fe/MgO催化剂的作用.发现这种预处理有利于Fe在催化剂中的稳定和分散,从而制备出管径均一的单壁碳纳米管.采用能谱元素分析、高分辨透射电镜、X射线衍射、比表面积测量、拉曼光谱和热重分析对样品进行了表征.结果表明,在碳纳米管生长的过程中,铁元素在催化剂表面富集,单壁碳纳米管生长于富集铁的纳米颗粒上,并存在碳管直径与铁颗粒尺寸的依赖关系.Mo存在时可煅烧形成FeMoO4复合氧化物,后者比MgFe2O4相更加稳定.Mo/Fe比例对提高单壁碳纳米管的生长密度、纯度与管径均一性等均有明显影响.上述研究对进一步精确控制制备单壁碳纳米管有重要意义. 相似文献
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Qun Zeng Zhenhua Li Yuhong Zhou 《天然气化学杂志》2006,15(3):235-246
Owing to the unique structure, the superior physical and chemical properties, the super strong mechanical performances, and so on, carbon nanotubes have attracted the attention of researchers all over the world. In this article, the basic properties and the main production processes of carbon nanotubes are introduced in brief, and the progress of applied research for carbon nanotubes is reviewed. 相似文献