Catalytic chemical vapor deposition

Multiwall carbon nanotubes (MWCNTs) have been synthesized by catalytic chemical vapor deposition (CCVD) of ethylene on several mesoporous aluminosilicates impregnated with iron. The aluminosilicates were synthesized by sol-gel method optimizing the Si/Al ratios from 6 to 80. The catalysts are characterized by nitrogen adsorption, X-ray diffraction, 27A1 NMR, thermogravimetric analysis (TGA) and infrared. The MWCNTs are characterized by TGA and transmission and scanning electron microscope. 

P. Coquay, E. Flahaut, E. de Grave, A. Peigney, R.E. Vandenberghe, and C. Laurent, Fe/Co alloys for the catalytic chemical vapor deposition synthesis of single- and double-walled carbon nanotubes (CNTs). 2. The CNT-Fe/Co-MgAl204 system. J. Phys. Chem. B 109, 17825-17830 (2005). 

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. 

J. K. Nahm, 5. Ju, B.-K. Synthesis of Double-Walled Carbon Nanotubes by Catalytic Chemical Vapor Deposition and Their Field Emission Properties. J. Phys. Chem. B 2006, 110,5310-5314. 

CCVD Catalytic chemical vapor deposition. Supported metal catalysts are used 1.5 (1.3-2) Cheapest, commercial, up-scalable. Most feasible from the application point of view... 

Nanocrystalline cubic SiC (P-SiC) films were grown on silicon (100) substrate by catalytic chemical vapor deposition (Cat-CVD) at a temperature as low as 300°C with a pre-carbonization process. To enhance nucleation density of P-SiC, a buffer layer was made by carbonizing the substrate surface. From the comparison between both carbonized sample and non-carbonized sample, the precarbonization process has beneficial effects on the growth of nanociystalline p-SiC films. Mechanistic interpretations are given to explain the carbonization process and catalyzing deposition process. 

Matsumura H., Catalytic chemical vapor deposition (CTL-CVD) method producing high quality hydrogenated amorphous silicon, Jpn. J. Appl Phys. 25 (1986) pp. L949-L952. 

Matsumura H., Low temperature depostition of silicon nitride by the catalytic chemical vapor deposition method, Jpn. J. Appl. Phys. 28 (1989) pp.2157-2160. 

Peeling of Si films tends to be suppressed also by using precursor a-Si films with less amount of hydrogen content [33], as in the case of EL A. From this point of view, catalytic chemical vapor deposition (Cat-CVD), which can... 

Several SWNT synthesis methods have been investigated during the last decade. Arc discharge, laser ablation, and catalytic chemical vapor deposition methods are described below. 

The catalytic decomposition of carbon-contaming compounds is an extensively investigated method, also known as catalytic chemical vapor deposition (CCVD). One of the advantages of this method is the potential for large-scale production at a lower energy consumption and overall cost than with other methods. The CCVD method is essentially the same as that used for a long time in the synthesis of other filamentous forms of carbon, such as nanofibers or fibrils. The CCVD method involves the catalytic decomposition of hydrocarbons or carbon monoxide on transition metal particles. The major difference with those processes that produce nanofibers is in the structure of the catalyst. To produce SWNT, the size of the metal cluster needs to be very small. Therefore, the success of a CCVD method lies in the design of the catalyst. 

VAPOR-GROWN CARBON FIBERS (VGCF) AND CATALYTIC CHEMICAL VAPOR-DEPOSITED (CCVD) FILAMENTS... 

The term vapor grown carbon fiber (VGCF) is an International Union of Pure and Applied Chemistry (lUPAC) recommendation and Tibbetts [1] believes that this term has won general acceptance for the class of material where a carbonaceous gas, in the presence of a small metal particle acting as a catalyst, forms a carbon filament. However, Dresselhaus and co-authors [2] use the term CCVD filament in their book, which stands for catalytic chemical vapor deposition and is certainly more descriptive of their mode of preparation, but is, unfortunately, not the generally accepted term. 

Arc-discharge Catalytic chemical vapor deposition Impurities bucky-onions and graphite particles Amor-phous carbonaceous material Average aspect ratio. 

Synthesis of CNT over oxides supports by Catalytic Chemical Vapor Deposition (CCVD) is one of the most important techniques for mass production of non-aligned CNT. It could be useful for the production of composite materials, field emission sources, fuel cells, supercapacitors among others technological applications. The CCVD method consists on the decomposition of a gas or a liquid precursor, which supplies carbon to the surface of the catalytic particles (e.g. Fe) in a tube furnace at temperatures around 900 °C. This technique is scalable for mass production at lower temperatures and could be adapted for continuous production. 

The catalytic chemical vapor deposition (CCVD) technique is far more developed and has great potential to be applied industrially. This technique allows for mass production at lower temperatures than the previously described methods and can be adapted for continuous production [69]. This method consists of decomposing a gas or a liquid precursor, which supplies carbon on catalytic particles (Fe, Ni, Co) in a mbe furnace at temperatures between 500 and 1,100 °C (Fig. 5.4). Besides the classic oven, heated by electric heaters, plasma furnaces (PECVD, Plasma-Enhanced Chemical Vapor Deposition) microwaves (nuCTowave, MW-PECVD), or DC (direct current, dc-PECVD) are also used. 

The following chapters present the general aspects of different synthesis of nanostructured materials, such as Combustion Synthesis (Chap. 2), Spray Pyrolysis (Chap. 3), Electro spinning (Chap. 4), Catalytical Chemical Vapor Deposition applied in the Synthesis of Carbon Nanotubes and Carbon Nanotubes Forests (Chap. 5), Hydrothermal Synthesis (Chap. 6) and High-Energy Milling (Chap. 7). 

Colomer JF, Stephan C, Lefrant S, Tendeloo GV, Willems 1, Kanya Z, et al. Large-scale synthesis of single-wall carbon nanotubes by catalytic chemical vapor deposition CCVD method. Chem Phys Lett 2000 317 83-9. 

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