Synthesis of Carbon Nanotubes

The synthesis of CNTs is reeeiving considerable interest and the main goal is to obtain large scale produetion of highly pure CNTs. There are three basic methods for synthesis of SWCNTs and MWCNTs eleetrical arch discharge, laser ablation (laser vaporization) and ehemical vapor deposition (CVD) (or catalytic decomposition of hydrocarbons) [1,7, 9,10, 25,26], 

Several are the parameters that affect the areh-diseharge nanotubes production such as gas type, pressure and flow rate, eleetrie field strength, electrode materials and dimensions, in addition to imquantified variables sueh as 

Gustavo A. Rivas, Maria D. Rubianes, Maria L. Pedano et al. 

This procedure involves the pyrolysis of gas molecules with high content in carbon at elevated temperatures in the presence of catalyst [10, 25]. There are two basic protocols, in one of them, called supported growth process (the most used), the catalyst is prepared and deposited on a support medium, which is inserted into a flow apparatus (a tube at atmospheric pressure in a temperature controlled furnace) and exposed to elevated temperatures, usually 500-1100 °C for a given time. In the other protocol, called floating-catalyst growth, the catalyst and the 

The first step in the development of advanced nanotechnology systems is the synthesis of the nanomaterial. Regarding carbon nanotubes, three principal methods are available  

Using the above methods, typical synthesis products are  

These products use graphite as the base material. In fact, using different precursors (e.g. aluminium, ceramics), with the same technological methods. 

Before describing the synthesis methods, it is useful to outline their characteristics. 

Requires a specific control of the environment using inert gases (helium and/or argon). 

The authors have been funded by the Comision Interministerial de Ciencia y Tecnologia (MAT2003-1052, CTQ2005-04968-C02-01, MAT2006-13572-C02-01) and GeneraUtat de Catalunya (2005SGR452, 2005SGR00305). 

Molins, J. Sort, S. Surinach, M. D. Baro, J. S. Munoz, L. Morellon, M. R. Ibarra, J. Nogues, Appl. Phys. Lett. 2003, 82, 4307-4309. 

Rodriguez, E. Molins, J. Tejada, J. Sort,/. Non-Cryst. Solids 2001, 285, 37-43. 

Molins, J. M. Greneche, J. Asenjo, J. Tejada, Appl. Phys. A-Mater. Sci. Process. 2002, 74, 591-597. 

Rodriguez, E. Molins, M. Moreno-Manas, A. Roig, R.M. Sebastian, A. Vallribera, Tetrahedron 2003, 59, 1553-1556. 

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The use of a stable glow discharge for the synthesis of carbon nanotubes... 

Large-Scale Synthesis of Carbon Nanotubes by Pyrolysis... 

Hernadi, H., Fonseca, A., Nagy, J. B. and Bemaerts, D., Catalytic synthesis of carbon nanotubes. In Supercarbon, Synthesis, Properties and Applications, ed. S. Yoshimura and R. P. H. Chang. Springer-Verlag, Heidelberg, 1998, pp. 75 91. 

The aluminum is incorporated in a tetrahedral way into the mesoporous structure, given place to Bronsted acidic sites which are corroborated by FTIR using pyridine as probe molecule. The presence of aluminum reduces the quantity of amorphous carbon produced in the synthesis of carbon nanotubes which does not happen for mesoporous silica impregnated only with iron. It was observed a decrease in thermal stability of MWCNTs due to the presence of more metal particles which help to their earlier oxidation process. 

Various nanoporous AAO membranes have been obtained by varying different parameters such as applied voltage, temperature of electrolyte, electrolytic concentration and speed of rotation of electrolyte in two step anodization process. SEM analysis performed for evaluation of results. The relationship between pore size and variation of different parameters obtained. The synthesized membranes have been used as template for the synthesis of carbon nanotubes of different nano dimensions. 

Chen YK, Chu A, Cook J, Green MLH, Harris PJF, Heesom R, Humphries M, Sloan J, Tsang SC, Turner JFC (1997) Synthesis of carbon nanotubes containing metal oxides and metals of the d-block and f-block transition metals and related studies. J. Mater. Chem. 7 545-549. 

Motta MS, Moisala A, Kinloch IA, Windle AH. The role of sulphur in the synthesis of carbon nanotubes by chemical vapour deposition at high temperatures. Journal of Nanoscience and Nanotechnology. 2008 May 8(5) 2442-9. 

Itami, K., Toward controlled synthesis of carbon nanotubes and graphenes. Pure and Appl. Chem. 2012,84 90Z-916. 

Lee, K., Zhang, J., Wang, H., and Wilkinson, D. P. Progress in the synthesis of carbon nanotube- and nanofiber-supported Pt electrocatalysts for PEM fuel cell catalysis. Journal of Applied Electrochemistry 2006 36 507-522. 

Recently, the efficacy of LDHs as catalyst precursors for the synthesis of carbon nanotubes via catalytic chemical vapor deposition of acetylene has been reported by Duan et al. [72]. Nanometer-sized cobalt particles were prepared by calcination and subsequent reduction of a single LDH precursor containing cobalt(II) and aluminum ions homogeneously dispersed at the atomic level. Multi-walled carbon nanotubes with uniform diameters were obtained. 

T.W. Ebessen, RM. Ajayan, Large-scale synthesis of carbon nanotubes, Nature 358(6383)... 

Hou S, Chung D, Lin T (2009) Flame synthesis of carbon nanotubes in a rotating counterflow. J Nanosci Nanotechnol 9 4826-4833... 

Since the synthesis of carbon nanotubes by Iijima [1, 2], a lot of investigations have been made on this kind of novel material [3-16]. Carbon nanotubes can be conventionally synthesized with several methods [17, 18], Recently, catalytic synthesis method has been developed to prepare carbon nanotubes on Co/Si02 [19, 20]. Hemadi et al. first extended the catalytic synthesis to the use of zeolites (NaY, HY and ZSM-5) as catalyst supports to synthesize carbon nanotubes [21]. 

The preparation of the used Fe-loading molecular sieves materials and the catalytic synthesis of carbon nanotubes have been described in detail in our previous report [22]. The textural properties and compositions of catalysts are shown in Table 1. XPS spectra for samples were recorded on a PHI-5300 ESCA system. The pass energy was 71.550 eV. Before the XPS measurement, all the samples were ground and then dried at 393 K for 2 h. For these samples, the C(ls) level (284.4 eV) was taken as the reference binding energy (B.E.). 

Laurent, Ch., Peigney, A., Flahaut, E., Rousset, A., Synthesis of carbon nanotubes-Fe-Al203 powders. Influence of the characteristics of the starting A11.8Fe0.2O3 oxide solid solution, Mat. Res. Bull., 35, 2000, 661-663. 

Che, G., Lakshmi, B.B., Martin, C.R., and Fisher, E.R. Chemical vapor deposition based synthesis of carbon nanotubes and nanofibers using a template method. Chem. Mater. 10, 1998 260-267. 

Gao, X.P., Qin, X., and Wu, F. (2000) Synthesis of carbon nanotubes by catalytic decomposition of methane using LaNi5 hydrogen storage alloy as a catalyst, Chem. Phys. Lett., 327, 271-276. 

The distinctive feature of the discussed method for nanostructural carbon material synthesis is that there is a possibility to produce these materials without catalysts owing to a very quick synthesis (competing with velocity of light). An example of such type of process is synthesis of carbon nanotubes by evaporation of pure graphite in liquid media. 

Schur D.V., Dubovoy A.G., Zaginaichenko S.Yu., Savenko A.F. Method for synthesis of carbon nanotubes in the liquid phase. Extended Abstracts, An International Conference on Carbon Providence (Rhode Island, USA) American Carbon Society, 2004 196-8. 

Rakov, E.G. (2004) Pyrolytic synthesis of carbon nanotubes and nano fibers, Ros. Khim. J. XLY111(5), 12-19. 

Qian W., Yu H., Wei F., Zhang Q., Wang Z. Synthesis of carbon nanotubes from liquefied petroleum gas containing sulfiir. Carbon, 2002,40(15), 2968-2970. 

FIGURE 1. Pyrolysis apparatus employed for the synthesis of carbon nanotubes by pyrolysis of mixtures of (a) metallocene + CaHa, (b) Fe(C0)s + C2H2, and (c) metallocene + benzene or thiophene. The numbers 1 and 2 indicated in the figure represents inlet and outlet, respectively.6... 

Sonoyama, N., et al. (2006), Synthesis of carbon nanotubes on carbon fibers by means of two-step thermochemical vapor deposition, Carbon, 44,1754-1761. 

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