scholarly journals Catalytic Chemical Vapor Deposition of Methane to Carbon Nanotubes: Copper Promoted Effect of Ni/MgO Catalysts

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Wen Yang ◽  
Yanyan Feng ◽  
Wei Chu
Keyword(s):  
Carbon Nanotubes ◽  
Chemical Vapor Deposition ◽  
Calcination Temperature ◽  
Reaction Temperature ◽  
Vapor Deposition ◽  
Sol Gel ◽  
Chemical Vapor ◽  
Growth And Yield ◽  
Calcination Temperatures ◽  
Temperature Programmed

The Ni/MgO and Ni-Cu/MgO catalysts were prepared by sol-gel method and used as the catalysts for synthesis of carbon nanotubes by thermal chemical vapor deposition. The effect of Cu on the carbon yield and structure was investigated, and the effects of calcination temperature and reaction temperature were also investigated. The catalysts and synthesized carbon materials were characterized by temperature programmed reduction (TPR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). Results showed that the addition of Cu promoted the reduction of nickel species, subsequently improving the growth and yield of CNTs. Meanwhile, CNTs were synthesized by the Ni/MgO and Ni-Cu/MgO catalysts with various calcination temperatures and reaction temperatures, and results suggested that the obtained CNTs on Ni-Cu/MgO catalyst with the calcination temperature of 500°C and the reaction temperature of 650°C were of the greatest yield and quantity of 927%.

Catalyst Support and Pretreatment Effects on Carbon Nanotubes Synthesis by Chemical Vapor Deposition of Methane on Iron over SiO2, Al2O3 or MgO

2009 ◽  
Vol 7 (1) ◽  
Author(s):  
M. Esmaieli ◽  
A. Khodadadi ◽  
Y. Mortazavi
Keyword(s):  
Carbon Nanotubes ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Iron Catalyst ◽  
Supported Catalysts ◽  
Catalyst Support ◽  
Multiwall Carbon Nanotubes ◽  
Chemical Vapor ◽  
Pretreatment Conditions ◽  
Temperature Programmed

In this study we report the effects of support and pretreatment conditions on growth of carbon nanotubes (CNTs) by chemical vapor deposition of methane on iron catalyst supported on MgO, silica or alumina. The iron was impregnated onto the supports, and then the samples were dried, calcined at 550°C and pretreated in either helium or hydrogen up to 1000°C before exposure to methane as a carbon source for CNTs growth. Temperature programmed reduction (TPR) of the fresh catalysts and the ones pre-treated in He and in H2 shows various interactions of the iron with supports at pretreatment conditions. The CNTs are characterized by SEM, Raman, FTIR, and TEM. The IG/ID of Raman spectroscopy are 6.2, 3.8 and 0.7 for the CNTs grown on the MgO, alumina, and silica-supported iron catalysts pretreated in helium, respectively. When the Fe/MgO catalyst is pretreated in hydrogen the IG/ID ratio dramatically reduces to 0.8. A less significant effect of pretreating of the catalysts in hydrogen is observed for silica- and alumina-supported catalysts. RBM peaks of Raman spectra along with TEM results indicate the formation of bundles of 0.8-1.2 nm single-wall as well as multiwall carbon nanotubes on the Fe/MgO catalyst pre-treated in He.

The Reaction of NH3 With TiN: Implications for CVD

1995 ◽  
Vol 410 ◽  
Author(s):  
Michelle T. Schulberg ◽  
Mark D. Allendorf ◽  
Duane A. Outka
Keyword(s):  
Activation Energy ◽  
Chemical Vapor Deposition ◽  
Reaction Temperature ◽  
Vapor Deposition ◽  
High Probability ◽  
Film Growth ◽  
Chemical Vapor ◽  
Temperature Programmed Desorption ◽  
Surface Sites ◽  
Temperature Programmed

ABSTRACTSince NH3 is an important component of TiN chemical vapor deposition (CVD) processes, understanding the NH3/TiN surface interaction is crucial to developing a model for the overall reaction. Temperature programmed desorption experiments show that NH3 adsorbs molecularly on amorphous TiN surfaces. Chemisorption occurs at only ∼5% of the surface sites, with an activation energy for desorption of 24 kcal/mol. The sticking probability into this state is 0.06 at 100 K. In addition, NH3 adsorbs with high probability into a multilayer state with an activation energy for desorption of 7.3 kcal/mol, similar to that found in other systems. NH3 does not dissociate on TiN. Under CVD conditions, however, the reactivity of NH3 on TiN may increase and surface reactions may play a part in film growth.

scholarly journals An Investigation on the Formation of Carbon Nanotubes by Two-Stage Chemical Vapor Deposition

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
M. S. Shamsudin ◽  
M. F. Achoi ◽  
M. N. Asiah ◽  
L. N. Ismail ◽  
A. B. Suriani ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Pyrolysis Temperature ◽  
Sol Gel ◽  
Chemical Vapor ◽  
Synthesis Process ◽  
Two Stage ◽  
Synthesis Time ◽  
Custom Made

High density of carbon nanotubes (CNTs) has been synthesized from agricultural hydrocarbon: camphor oil using a one-hour synthesis time and a titanium dioxide sol gel catalyst. The pyrolysis temperature is studied in the range of 700–900°C at increments of 50°C. The synthesis process is done using a custom-made two-stage catalytic chemical vapor deposition apparatus. The CNT characteristics are investigated by field emission scanning electron microscopy and micro-Raman spectroscopy. The experimental results showed that structural properties of CNT are highly dependent on pyrolysis temperature changes.

Cobalt supported on carbon nanotubes for methane chemical vapor deposition towards carbon nanotubes

2021 ◽  
Author(s):  
Laura Esteves ◽  
Hugo Alvarenga Oliveira ◽  
Y. T. Xing ◽  
Fabio Barboza Passos
Keyword(s):  
Carbon Nanotubes ◽  
Chemical Vapor Deposition ◽  
Heterogeneous Catalysis ◽  
Vapor Deposition ◽  
Supported Catalysts ◽  
Chemical Vapor

Carbon nanotubes (CNT) application in heterogeneous catalysis has been attracting growing interest. However, the use of CNT-supported catalysts in the chemical vapor deposition for the production of new CNT is...

Fabrication of short and straight carbon nanotubes by chemical vapor deposition

2008 ◽  
Vol 476 (1-2) ◽  
pp. 230-233 ◽  
Author(s):  
Haipeng Li ◽  
Naiqin Zhao ◽  
Chunnian He ◽  
Chunsheng Shi ◽  
Xiwen Du ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor
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