623 Examination of the carbon nanotubes composition condition in CVD method and flame synthesis

2014 ◽  
Vol 2014.50 (0) ◽  
pp. 149-150
Author(s):  
Mitsuaki ODA ◽  
Masaaki OKUYAMA
Author(s):  
Sergey V. Bulyarskiy 1 ◽  
Alexander A. Dudin 1 ◽  
Alexander V. Lakalin 1 ◽  
Andrey P. Orlov 1 ◽  
Alexander A. Pavlov 1 ◽  
...  

We have studied the effect of the series resistance on the heating of the cathode, which is based on carbon nanotubes and serves to realize the field emission of electrons into the vacuum. The experiment was performed with the single multi-walled carbon nanotube (MCNT) that was separated from the array grown by CVD method with thin-film Ni-Ti catalyst (nickel 4 nm / Ti 10 nm). The heating of the cathode leads to the appearance of a current of the thermionic emission. The experimental voltage current characteristic exhibited the negative resistance region caused by thermal field emission. This current increases strongly with increasing voltage and contributes to the degradation of the cold emitter. The calculation of the temperature of the end of the cathode is made taking into account the effect of the phenomenon that warms up and cools the cathode. We have developed a method for processing of the emission volt-ampere characteristics of a cathode, which relies on a numerical calculation of the field emission current and the comparison of these calculations with experiments. The model of the volt-ampere characteristic takes into account the CNT’s geometry, properties, its contact with the catalyst; heating and simultaneous implementation of the thermionic and field emission. The calculation made it possible to determine a number of important parameters, among which the voltage and current of the beginning of thermionic emission, the temperature distribution along the cathode, the resistance of the nanotube. The phenomenon of thermionic emission from CNT’s was investigated experimentally and theoretically. The conditions of this type emission occurrence were defined. The results of the study could form the basis of theory of CNT emitter’s degradation.


Author(s):  
Huynh Anh Hoang ◽  
Huynh Quyen

Since the end of the 20th century, nanomaterials such as carbon nanotubes (CNTs) have been considered as one of the greatest achievements in the field of material science. Nowadays, further research on CNTs is still being conducted to unfold the full potential of this material. Generally, CNTs production methods have been extensively studied, specifically on CNTs synthesis route via liquefied hydrocarbon gas in the presence of a catalyst. From the synthesized material, further investigation including characterization and investigation of this nano size system’s effects on the physics, chemical, mechanical rules applied to macroscopic (bulk materials) and microscopic systems (atoms, molecules). In this present work, we demonstrated the research results of the synthesis of nano-carbon materials from a liquefied hydrocarbon gas (Liquefied Petroleum Gas: LPG) and its application to red phenol absorption in the liquid phase. CNTs used in this study were synthesized by chemical vapor deposition (CVD) method with Fe /ℽ-Al2O3 as the catalyst. The research results demonstrated that CNTs synthesized from LPG in this work were reported to be multi-walled tubes (MWCNTs: Multi-Walled Carbon Nanotubes) with physical characteristics including average internal and external diameters were of 6 nm and 17 nm, respectively. The measured specific surface suggested by BET data was 200 m2/g. The experimental study of red phenol adsorption by MWCNTs showed that the adsorption process followed both Freundlich and Langmuir isotherm adsorption models with the maximum monolayer adsorption capacity of 47.2 mg/g. The research results again showed that it was possible to synthesize MWCNTs from hydrocarbon gas sources via the CVD method by utilizing catalysts. Additionally, red phenol absorption via such material had shown to follow both Freundlich and Langmuir isotherm model, which allow further characterization of this material using Raman, EDX, SEM, TEM, BET, in order to extend the library database on the characterization of the reported synthesized material.


2016 ◽  
Vol 291 ◽  
pp. 106-114 ◽  
Author(s):  
G. Pilatos ◽  
M. Samouhos ◽  
P. Angelopoulos ◽  
M. Taxiarchou ◽  
Ch. Veziri ◽  
...  

Author(s):  
N. Hamzah ◽  
M. F. Mohd Yasin ◽  
M. T. Zainal ◽  
M. Mohd Sies ◽  
M. Z. Mohd Yusop ◽  
...  

Nano Letters ◽  
2004 ◽  
Vol 4 (2) ◽  
pp. 317-321 ◽  
Author(s):  
Yiming Li ◽  
David Mann ◽  
Marco Rolandi ◽  
Woong Kim ◽  
Ant Ural ◽  
...  

2012 ◽  
Vol 486 ◽  
pp. 8-11
Author(s):  
Yuan Yuan ◽  
Bao Min Sun ◽  
Xiao Tian Wang ◽  
Yang Wang ◽  
Yong Hong Guo

Catalysts play a critical role in the synthesis of carbon nanotubes. In this paper, we design a series of experiments to explore the impact of contents of Mo on the products. Analysis show, when the molar ratio of Fe: Mo: Al is 1: 0.2: 16, the carbon nanotubes show the best yields and quality.


2006 ◽  
Vol 320 ◽  
pp. 163-166 ◽  
Author(s):  
Koji Yamada ◽  
Kentaro Abe ◽  
Masafumi Mikami ◽  
Morihiro Saito ◽  
Jun Kuwano

Multi-walled carbon nanotubes (MWCNTs) were synthesized from camphor by a chemical vapor deposition (CVD) method in a range of 750-900. The catalyst was fed in three ways: (a) a sputtered Fe-film on a quartz substrate (b) vaporized ferrocene in an Ar flow; (c) both of (a) and (b). In the case (c), highly pure, dense and aligned MWCNT arrays formed on the quartz substrate at 850, whereas nonaligned MWCNTs formed in the cases (a) and (b).


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