scholarly journals Electron Irradiation of Carbon Nanotubes: A Credible Defect Generation Technique to Improve Hydrogen Storage for Future

1970 ◽  
Vol 45 (4) ◽  
pp. 337-344
Author(s):  
AKM Fazle Kibria
Keyword(s):  
Carbon Nanotubes ◽  
Hydrogen Storage ◽  
Electron Irradiation ◽  
Topological Defects ◽  
Ccd Camera ◽  
Atomic Scale ◽  
Transmission Electron ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Induced Defects

Electron irradiation technique was employed to induce atomic-scale defects in the walls of multi-walled carbon nanotubes (MWCNTs) using electron beam of energy 120 keV and dose of 2.16 x 1017 electrons cm-2s-1. Structural transformations of the tubes attributable to irradiation exposure were monitored by high-resolution transmission electron microscope (HRTEM) and recorded by the connected CCD camera. It was observed that only five seconds (5s) of irradiation could shrink MWCNTs of diameter 15 nm having 11 graphitic layers towards the interior hole up to 2.2 nm and bend the tube. Irradiation incorporated vacancies and the topological defects generated on the tube walls were responsible for it. It was found that the electron irradiation could destroy such MWCNTs within 9 minutes. It was speculated that irradiation induced vacancies and their adjacent dangling bonds (DBs), the pentagon and octagon rings originated from the transformations of vacancies are highly influential to enhance the hydrogen storage in MWCNTs. From the time dependent HRTEM observations, it was found out that electron irradiation period less than 4 minutes is the optimum exposure time to achieve benefit of hydrogen storage in the MWCNTs as used in the present investigation. Electron irradiation induced defects could be used to enhance hydrogen storage in MWCNTs for future applications. Keywords: Carbon nanotube; Electron irradiation; Defect; Vacancy; Hydrogen storage DOI: 10.3329/bjsir.v45i4.7378 Bangladesh J. Sci. Ind. Res. 45(4), 337-344, 2010

scholarly journals Structural Modifications of Multi-walled Carbon Nanotubes of Different Diameters through Electron Beam Irradiation

1970 ◽  
Vol 46 (1) ◽  
pp. 9-16 ◽  
Author(s):  
AKM Fazle Kibria
Keyword(s):  
Carbon Nanotubes ◽  
Electron Beam ◽  
Electron Irradiation ◽  
Structural Modifications ◽  
Multi Walled Carbon Nanotubes ◽  
Graphitic Shell ◽  
Different Diameters ◽  
Walled Carbon Nanotubes ◽  
Induced Defects ◽  
Irradiation Induced Defects

The effects of irradiation on the structure of purified multi-walled carbon nanotubes (MWCNTs) having 6-19 graphitic shells and outer diameters of 8.15-17.11 nm were investigated using electron beam of energies 200 keV and dose of 2.16 x 1017 e cm-2s-1. It was observed that the electron irradiation created a number of chronological alterations in the tube structures. These were identified to be tube contraction, destruction of the innermost graphitic shell, deformation of graphitic shells and its proliferation, break down of the graphitic shells and their spreading into the tube hole and finally the destruction of the whole tube. MWCNTs having the largest innermost diameter found suffer from the highest contraction. The tube contraction behavior found stops when the innermost graphitic shell starts to destroy. Irradiation affected the innermost graphitic shell first and that of the smallest diameter was the more rapidly. It occurred probably due to having the highest curvature value. Tubes having inner shell of diameter about 4.8 nm suffer from fractional destruction within 5-15 s of irradiation exposure. Such a shell was ruined within 1 minute of irradiation exposure but that of diameter 7.0 nm was survived up to 2 minutes. It seems that the irradiation induced defects created in the MWCNTs can be used for the diversified applications of nanotubes such as the hydrogen storage enhancement in them. Keywords: Carbon nanotube; Electron irradiation; Tube contraction; Innermost shell; Defect. DOI: http://dx.doi.org/10.3329/bjsir.v46i1.8099 Bangladesh J. Sci. Ind. Res. 46(1), 9-16, 2011  

scholarly journals Biocompatibility Characteristics of Titanium Coated with Multi Walled Carbon Nanotubes—Hydroxyapatite Nanocomposites

Materials ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 224 ◽  
Author(s):  
Jung-Eun Park ◽  
Yong-Seok Jang ◽  
Tae-Sung Bae ◽  
Min-Ho Lee
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Sol Gel ◽  
Pure Titanium ◽  
Cell Proliferation And Differentiation ◽  
Transmission Electron ◽  
Proliferation And Differentiation ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

Multi walled carbon nanotubes-hydroxyapatite (MWCNTs-HA) with various contents of MWCNTs was synthesized using the sol-gel method. MWCNTs-HA composites were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). HA particles were generated on the surface of MWCNT. Produced MWCNTs-HA nanocomposites were coated on pure titanium (PT). Characteristic of the titanium coated MWCNTs-HA was evaluated by field-emission scanning electron microscopy (FE-SEM) and XRD. The results show that the titanium surface was covered with MWCNTs-HA nanoparticles and MWCNTs help form the crystalized hydroxyapatite. Furthermore, the MWCNTs-HA coated titanium was investigated for in vitro cellular responses. Cell proliferation and differentiation were improved on the surface of MWCNT-HA coated titanium.

Study on Electrochemical Hydrogen Storage of Multi-Walled Carbon Nanotubes

2007 ◽  
Vol 26-28 ◽  
pp. 831-834 ◽  
Author(s):  
Lei Xie ◽  
Xiao Qi Li
Keyword(s):  
Carbon Nanotubes ◽  
Hydrogen Storage ◽  
Storage Capacity ◽  
Weight Percent ◽  
Chemical Form ◽  
Hydrogen Storage Capacity ◽  
Electrochemical Hydrogen Storage ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Discharging Capacity

The electrode(Ni-MWNTs) containing nickel(Ni) and multi-walled carbon nanotubes (MWNTs) was prepared by composite electrodeposit. Electrochemical hydrogen storage of the electrode was studied. The result showed a high electrochemical discharging capacity of up to 1361.1mA·h·g-1, which corresponds to a hydrogen storage capacity of 4.77Wt%(weight percent). Test of cyclic lifespan showed MWNTs had certain cyclic lifespan. Cyclic voltammetry tests showed that MWNTs can store hydrogen in chemical form.

scholarly journals Carbon Nanofibers from Carbon Nanotubes by 1.2 keVAr+Sputtering at Room Temperature

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Shuang-Xi Xue ◽  
Qin-Tao Li ◽  
Xian-Rui Zhao ◽  
Qin-Yi Shi ◽  
Zhi-Gang Li ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Carbon Nanofibers ◽  
Carbon Nanoparticles ◽  
Room Temperature ◽  
Ion Irradiation ◽  
Transmission Electron ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Carbon Nanowires

Multi-walled carbon nanotubes (MWCNTs) were irradiated by 1.2 keV Ar ion beams for 15–60 min at room temperature with current density of 60 µA/cm2. The morphology and microstructure are investigated by scanning electron microscopy, transmission electron microscopy and Raman spectroscopy. The results show that carbon nanofibers are achieved after 60 min ion irradiation and the formation of carbon nanofibers proceeds through four periods, carbon nanotubes—amorphous carbon nanowires—carbon nanoparticles along the tube axis—conical protrusions on the nanoparticles surface—carbon nanofibers from the conical protrusions.

Formation Mechanism and Microwave Permittivity of Carbon Nanotubes Filled with Metallic Silver Nanowires

2007 ◽  
Vol 334-335 ◽  
pp. 685-688
Author(s):  
Dong Lin Zhao ◽  
Xia Li ◽  
Wei Dong Chi ◽  
Zeng Min Shen
Keyword(s):  
Carbon Nanotubes ◽  
Formation Mechanism ◽  
Silver Nanowires ◽  
Nitrate Solution ◽  
Silver Nitrate Solution ◽  
Metallic Silver ◽  
Transmission Electron ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Microwave Permittivity

The filling of multi-walled carbon nanotubes (MWNTs) with metallic silver nanowires via wet chemistry method was investigated. The carbon nanotubes were filled with long continuous silver nanowires. The carbon nanotubes were almost opened and cut after being treated with concentrated nitric acid. Silver nitrate solution filled carbon nanotubes by capillarity. Carbon nanotubes were filled with silver nanowires after calcinations by hydrogen. The diameters of silver nanowires were in the range of 20-40nm, and lengths of 100nm-10μm. We studied the micromorphology of the silver nanowires filled in carbon nanotubes by transmission electron microscopy (TEM) and X-ray diffraction (XRD). Based on the experimental results, a formation mechanism of the Ag nanowire-filled carbon nanotubes was proposed. And the microwave permittivity of the carbon nanotubes filled with metallic silver nanowires was measured in the frequency range from 2 GHz to 18 GHz. The loss tangent of the carbon nanotubes filled with metallic silver nanowires is high. So the carbon nanotubes filled with metallic silver nanowires would be a good candidate for microwave absorbent.

Ultrasound promoted green oxidation of alkenes with hydrogen peroxide in the presence of iron porphyrins supported on multi-walled carbon nanotubes

2015 ◽  
Vol 19 (04) ◽  
pp. 622-630 ◽  
Author(s):  
Saeed Rayati ◽  
Zahra Sheybanifard
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Hydrogen Peroxide ◽  
Heterogeneous Catalyst ◽  
Multi Wall Carbon Nanotubes ◽  
Mechanical Stirring ◽  
Transmission Electron ◽  
Multi Walled Carbon Nanotubes ◽  
Ft Ir ◽  
Walled Carbon Nanotubes

In the present work, oxidation of alkenes with hydrogen peroxide in the presence of meso-tetrakis(4-hydroxyphenyl)porphyrinatoiron(III) chloride supported onto surface of functionalized multi-wall carbon nanotubes (FMWCNT), [ Fe ( THPP ) Cl@MWCNT ], is reported. The simple heterogeneous catalyst was characterized by FT-IR spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and also thermal analysis. The amount of the catalyst loaded on the nanotubes was determined by atomic absorption spectroscopy. This heterogeneous catalyst proved to be an efficient and green catalyst and was successfully able to activate hydrogen peroxide without any additive toward the oxidation of alkenes in ethanol as a green solvent. Performance of the catalyst in oxidation of various alkenes was inspected under reflux, ultrasonic irradiation and mechanical stirring. Moreover, the catalyst can be reused several times under similar conditions.

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