Study of surface defects and crystallinity of MWCNTs growth in FCCVD

2017 ◽  
Vol 24 (6) ◽  
pp. 845-851
Author(s):  
Shazia Shukrullah ◽  
Norani Muti Mohamed ◽  
Maizatul Shima Shaharun ◽  
Muhammad Yasin Naz
Keyword(s):  
Carbon Nanotubes ◽  
Surface Defects ◽  
Chemical Vapor ◽  
Raman Peak ◽  
Multiwalled Carbon ◽  
Peak Intensity ◽  
Black Spots ◽  
Pure Carbon ◽  
Structural Growth ◽  
Raman Peak Intensity

AbstractThis research investigated the structural growth of multiwalled carbon nanotubes (MWCNTs) in a double stage horizontal chemical vapor deposition (CVD) reactor. Ethylene was used as a carbon source for nucleation of nanotubes. Ferrocene catalyst weight was varied from 0.1 to 0.2 g to demonstrate the growth of MWCNTs on Si/SiO2/Al2O3 substrate. The obtained data revealed that the weight of the catalyst significantly affects the diameter, crystallinity, alignment and yield of the nanotubes. Lower inner-shell spacing and the ratio of D-Raman peak intensity and G-Raman peak intensity (ID/IG ratio) were obtained with 0.15 g of ferrocene, which was an indication of relatively pure carbon nanotubes (CNTs) growth. Raman spectra also confirmed the highly crystalline and relatively pure CNTs structures with ID/IG ratio of 0.700. TGA data revealed the formation of 97% pure nanotubes with oxidation temperature of 620°C. However, above and below the optimum (0.15 g of ferrocene), some of the grown CNTs were found defective and few black spots were also seen in TEM micrographs.

High Production of Carbon Nanotube Bundles with Fe2O3/Al2O3 Catalyst

2014 ◽  
Vol 695 ◽  
pp. 122-126 ◽  
Author(s):  
Shazia Shukrullah ◽  
Norani Muti Mohamed ◽  
Maizatul Shima Shaharun
Keyword(s):  
Electron Microscopy ◽  
Surface Defects ◽  
Chemical Vapor ◽  
Precipitation Method ◽  
High Yield ◽  
Outer Diameter ◽  
Multiwalled Carbon ◽  
Transmission Electron ◽  
Black Spots ◽  
Co Precipitation

In this study, Fe2O3/Al2O3catalyst was prepared by using co-precipitation method. This catalyst weight was varied from 0.1 to 0.5 g and multiwalled carbon nanotubes (MWCNTs) bundles were synthesized with ethylene as a carbon precursor at reaction temperature of 800°C by using floating catalytic chemical vapor deposition reactor. The grown MWCNTs bundles were characterized by using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy. The obtained data revealed that as prepared CNTs actually existed in bundles and these should be attributed to the Fe2O3/Al2O3catalyst, as transition metal Mo was not used in the catalyst. It was noted that an increase in weight of the catalyst significantly affects the quality, quantity, crystallinity, diameter and the growth of nanotubes bundles. Nanotubes yield increased with an increase in Fe2O3/Al2O3weight. The carbon yield obtained with different weights of Fe2O3/Al2O3was ranging from 68-93%. However, the surface defects in the grown tubes were also increased with an increase in the catalyst weight. High purity and high yield with the low surface defects was found for 0.3 g catalyst. It was found that less value of ID/IGratio (0.78) was obtained in case of 0.3 g catalyst which indicated the structural perfection and low defect levels. The average outer diameter of the grown CNTs bundles were ranged from 240 to 550 nm. The formation of CNTs bundles were found defective with few black spots and impure above and below the use of 0.3 g catalyst.

Multiwalled Carbon Nanotubes by Chemical Vapor Deposition Using Multilayered Metal Catalysts

2002 ◽  
Vol 106 (22) ◽  
pp. 5629-5635 ◽  
Author(s):  
Lance Delzeit ◽  
Cattien V. Nguyen ◽  
Bin Chen ◽  
Ramsey Stevens ◽  
Alan Cassell ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Chemical Vapor Deposition ◽  
Multiwalled Carbon Nanotubes ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Metal Catalysts ◽  
Multiwalled Carbon

In-Situ Characterization of Carbon Nanotube-Polystyrene Composite Deformation

2000 ◽  
Vol 6 (S2) ◽  
pp. 40-41
Author(s):  
D. Qian ◽  
E. C. Dickey ◽  
R. Andrews ◽  
T. Rantell ◽  
B. Safadi
Keyword(s):  
Carbon Nanotubes ◽  
Load Transfer ◽  
Electronic Materials ◽  
Composite Films ◽  
Chemical Vapor ◽  
Ex Situ ◽  
In Situ Tem ◽  
Multiwalled Carbon ◽  
Young’S Moduli

Carbon nanotubes (NTs) have novel electronic properties and exceptionally high Young's moduli on the order of TPa. so NTs have potential applications in advanced composite materials such as conductive polymers, electromagnetic-radio frequency interference (EMI/RFI) shielding material and opto-electronic materials. The utility of the nanotubes in composite applications depends strongly on the ability to disperse the NTs homogeneously throughout the matrix without destroying the integrity of the NTs. Furthermore, interfacial bonding between the NT and matrix is necessary to achieve load transfer across the interface, which is desirable for improving the mechanical properties of polymer composites.In this work, aligned multiwalled carbon nanotubes (MWNTs) produced by continuous chemical vapor deposition (CVD) (see Fig.l), were homogeneously dispersed in polystyrene (PS) matrices by a simple solution-evaporation method. Using this procedure, we made uniform MWNT-PS composite films ∼0.4mm thick for ex-situ mechanical tensile test and very thin films, ∼100nm, for in-situ TEM tests, as shown in Fig.2.

New Raman-Peak at 1850 cm−1 Observed in Multiwalled Carbon Nanotubes Produced by Hydrogen Arc Discharge

2010 ◽  
Vol 10 (6) ◽  
pp. 4038-4042 ◽  
Author(s):  
B. Chen ◽  
Y. Kadowaki ◽  
S. Inoue ◽  
M. Ohkohchi ◽  
X. Zhao ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Multiwalled Carbon Nanotubes ◽  
Arc Discharge ◽  
Raman Peak ◽  
Multiwalled Carbon

The Catalytic Effect on Vertically Aligned Carbon Nanotubes

2003 ◽  
Vol 800 ◽  
Author(s):  
Nam Seo Kim ◽  
Seung Yong Bae ◽  
Jeunghee Park
Keyword(s):  
Carbon Nanotubes ◽  
Growth Rate ◽  
Nitrogen Content ◽  
Catalytic Effect ◽  
Bulk Diffusion ◽  
Chemical Vapor ◽  
Decisive Role ◽  
Crystalline Perfection ◽  
Multiwalled Carbon ◽  
Vertically Aligned

ABSTRACTWe report the catalytic effect on the synthesis of multiwalled carbon nanotubes (CNTs). The CNTs were grown vertically aligned on the iron (Fe), cobalt (Co), and nickel (Ni) catalytic nanoparticles deposited on alumina substrates by thermal chemical vapor deposition (CVD) of acetylene in the temperature range 900–1000 °C. We also synthesized them on the silicon oxide substrates by pyrolyzing iron phthalocyanine (FePc), cobalt phthalocyanine (CoPc), and nickel phthalocyanine (NiPc) at 700–1000 °C. In both syntheses, the CNTs grown using Fe exhibit about 2 times higher growth rate than those using Co and Ni. As the temperature rises from 700 to 1000 °C, the growth rate of CNTs increases by a factor of 45. The Arrhenius plot of growth rates provides the activation energy 30 ± 3 kcal/mol for all three catalysts, which is similar with the diffusion energy of carbon in bulk metal. It suggests that the bulk diffusion of carbon would play a decisive role in the growth of CNTs. The diameter of CNTs is in the range of 20–100 nm, showing an increase with the temperature. As the diameter is below 30 nm, the CNTs usually exhibit a cylindrical structure. The CNTs were intrinsically doped with the nitrogen content 2–6 atomic%. The degree of crystalline perfection of the graphitic sheets increases with the temperature, but depends on the catalyst and the nitrogen content. The graphitic sheets of CNTs grown using Fe are better crystalline than those grown using Co and Ni. As the nitrogen content increases, the degree of crystalline perfection decreases and the structure becomes the bamboolike structure probably due to a release of strains.

Highly Organized Carbon Nanotube-PDMS Hybrid System for Multifunctional Flexible Devices

2007 ◽  
Author(s):  
Yung J. Jung ◽  
Laila Jaber-Ansari ◽  
Xugang Xiong ◽  
Sinan Mu¨ftu¨ ◽  
Ahmed Busnaina ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Electric Fields ◽  
Composite Structures ◽  
Field Enhancement ◽  
Chemical Vapor ◽  
Casting Process ◽  
Dip Coating ◽  
Network Architectures ◽  
Multiwalled Carbon

We will present a method to fabricate a new class of hybrid composite structures based on highly organized multiwalled carbon nanotube (MWNT) and singlewalled carbon nanotube (SWNT) network architectures and a polydimethylsiloxane (PDMS) matrix for the prototype high performance flexible systems which could be used for many daily-use applications. To build 1–3 dimensional highly organized network architectures with carbon nanotubes (both MWNT and SWNT) in macro/micro/nanoscale we used various nanotube assembly processes such as selective growth of carbon nanotubes using chemical vapor deposition (CVD) and self-assembly of nanotubes on the patterned trenches through solution evaporation with dip coating. Then these vertically or horizontally aligned and assembled nanotube architectures and networks are transferred in PDMS matrix using casting process thereby creating highly organized carbon nanotube based flexible composite structures. The PDMS matrix undergoes excellent conformal filling within the dense nanotube network, giving rise to extremely flexible conducting structures with unique electromechanical properties. We will demonstrate its robustness under large stress conditions, under which the composite is found to retain its conducting nature. We will also demonstrate that these structures can be directly utilized as flexible field-emission devices. Our devices show some of the best field enhancement factors and turn-on electric fields reported so far.

Sign in / Sign up

Export Citation Format

Share Document