scholarly journals Low Kinetic Energy Oxygen Ion Irradiation of Vertically Aligned Carbon Nanotubes

2019 ◽  
Vol 9 (24) ◽  
pp. 5342 ◽  
Author(s):  
Selene Acosta ◽  
Juan Casanova Chafer ◽  
Ayrton Sierra Castillo ◽  
Eduard Llobet ◽  
Rony Snyders ◽  
...  

Vertically aligned multiwalled carbon nanotubes (v-CNTs) were functionalized with oxygen groups using low kinetic energy oxygen ion irradiation. X-ray photoelectron spectroscopy (XPS) analysis indicates that oxygen ion irradiation produces three different types of oxygen functional groups at the CNTs surface: epoxide, carbonyl and carboxyl groups. The relative concentration of these groups depends on the parameters used for oxygen ion irradiation. Scanning electron microscopy (SEM) shows that the macroscopic structure and alignment of v-CNTS are not affected by the ion irradiation and transmission electron microscopy (TEM) proves tip functionalization of v-CNTs. We observed that in comparison to oxygen plasma treatment, oxygen ion irradiation shows higher functionalization efficiency and versatility. Ion irradiation leads to higher amount of oxygen grafting at the v-CNTs surface, besides different functional groups and their relative concentration can be tuned varying the irradiation parameters.


2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Shuang-Xi Xue ◽  
Qin-Tao Li ◽  
Xian-Rui Zhao ◽  
Qin-Yi Shi ◽  
Zhi-Gang Li ◽  
...  

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.



2016 ◽  
Vol 73 (11) ◽  
pp. 2638-2643 ◽  
Author(s):  
Shahab Karimifard ◽  
Mohammad Reza Alavi Moghaddam

In this study, the microwave regeneration method was applied to investigate the properties and adsorptive performance of functionalized carbon nanotubes (f-CNTs) in different cycles of regeneration/reuse. For this purpose, an organic and hazardous dye (Reactive Blue 19) was chosen as a widely used pollutant. N2 adsorption/desorption isotherms, scanning electron microscopy and Fourier transform infrared spectroscopy were used to characterize f-CNTs during the regeneration/reuse procedure. The morphology, specific surface area and pore volume of f-CNT samples were not significantly altered. However, the functional groups present on the f-CNTs’ surface were gradually removed after successive cycles of regeneration/reuse. A sudden decrease of adsorption capacity (about 20%) after the first cycle of regeneration/reuse was attributed to the elimination of functional groups interacting with the dye molecules because of the molecular-level heating. Relatively high regeneration efficiencies (73.30 to 80.16%) proved that the microwave regeneration method was successful. Very high step stripping efficiencies (80.16 to 98.02%) in four cycles of regeneration/reuse demonstrated that the microwave regeneration method could be utilized in consecutive cycles. After four cycles of regeneration/reuse, the CNTs could not be considered as functionalized.



Author(s):  
Kei Ishikawa ◽  
Hai Duong ◽  
Junichiro Shiomi ◽  
Shigeo Maruyama

Evaporation of different metals (Au, Ti, Al and Pd) onto Vertically-Aligned Single-Walled Carbon Nanotubes (VASWNT) has been studied. Observations through Scanning Electron Microscopy (SEM) showed a clear metal-dependence of the deposition layer structure on top of the VASWNT, reflecting the variation of wettability and cohesive energy of each metal. These characteristics also influence the structures of the metal penetrated through the top surface into VASWNT film, where metal forms particles inside VASWNT film except for Ti. A simple annealing technique to remove metals penetrated in the SWNT films is demonstrated. Some peculiar morphologies found during the processes are also presented.



MRS Advances ◽  
2020 ◽  
Vol 5 (52-53) ◽  
pp. 2679-2684
Author(s):  
Dashuai Li ◽  
Ling Tong ◽  
Bo Gao

AbstractAn atmospheric pressure microwave plasma tubular furnace apparatus (MPTF) for the rapid synthesis of carbon nanotubes (CNTs) has been developed. CNTs have been synthesized by an Argon-Hydrogen microwave plasma using ethanol vapor as carbon source with the furnace temperature of 800 °C at the atmospheric pressure. The synthesized CNTs have been analyzed by scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), and are shown to be multi-walled and tangled and chemically connected to form a high-density network with the diameter at the range of 25-70 nm. The measurement of X-ray photoelectron spectroscopy (XPS) indicates that a large number of oxygenated functional groups grown on the surface of CNTs. These properties proved that the CNTs could be utilized as nanoscale templates for various applications.



2011 ◽  
Vol 364 ◽  
pp. 398-401
Author(s):  
Johari Md Salleh ◽  
Aziah Buang Nor ◽  
Muhammad Zamir Othman

Manganese dioxide nanostructered (MnO2) was coated onto carbon nanotubes (CNTs) by simple immersion of the CNTs into a KMnO4 aqueous solution. The morphology of the CNTs before and after MnO2 deposition was examined using field emission scanning electron microscopy (FESEM) and high resolution transmission electron microscopy (HRTEM). The superfine coral-like MnO2 deposited and fully covered on the CNTs surface at pH 8. At pH 2 and 6 the MnO2 deposited as the superfine nanorod structure. The superfine MnO2 phase was identified as Birnessite-type MnO2 by X-ray powder diffraction and FESEM. The thermal stability of the superfine nanostructure MnO2 coated CNTs is increase based on the TGA with the weight loss of 4% at 400°C to 900°C.



2009 ◽  
Vol 81 (12) ◽  
pp. 2317-2325 ◽  
Author(s):  
Wei-De Zhang ◽  
Jin Chen

Strongly bonded arrays of vertically aligned, multi-walled carbon nanotubes (MWNTs) have been successfully grown on Ta foils, and provide a convenient basis for fabricating electrodes with high conductivity and stability. The MWNT arrays were further coated by nanostructured MnO2 through reacting with KMnO4 solution at room temperature. The morphology of the MnO2/MWNT nanocomposite was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It was found that the MnO2 is a beehive-like nanostructure that is homogeneously and densely coated on the surface of the MWNTs. The capacitance of the MWNT electrode was significantly increased from 0.14 to 6.81 mF cm–2 after being modified with nanostructured MnO2, that is, the mass-specific capacitance of the bare and MnO2-modified MWNTs was about 33 and 446 F g–1, respectively. The MnO2/MWNT nanocomposite on Ta foils could be potential for developing a supercapacitor.



2016 ◽  
Vol 693 ◽  
pp. 541-547 ◽  
Author(s):  
Qin Tao Li ◽  
Hong Jun Wang

The carbon nanotubes (CNTs) modified by the carbon particles with diameter of 120-180 nm are prepared by using hydrocarbon ion deposition techniques. Based on the investigation of scanning electron microscopy and transmission electron microscopy, the CNTs are decorated by some nanospheres with size of 120-180 nm randomly, and the full CNTs surface besides the area of nanosphere is coated by the graphene stacks with size of 10-15 nm. The nanospheres are composed of several nanoparticles of graphene stacks and are seamless connected with graphene stacks. The sparse distribution CNTs on Si substrate is crucial for the formation of carbon nanospheres. The formation of carbon nanospheres proceeds through the following three stages: the formation of graphene nanoparticle on CNTs surface and silicon substrate – the migration of active hydrocarbon groups towards the surface of the CNTs deposition zone at high temperature – the formation of carbon nanospheres by the aggregating hydrocarbon active groups.



2011 ◽  
Vol 418-420 ◽  
pp. 428-435
Author(s):  
Shao Ming Fang ◽  
Jia You Tang ◽  
Li Jun Gao ◽  
Li Ming Zhou

In this paper, europium hydroxide (Eu(OH)3) was introduced onto multiwall carbon nanotubes (MWCNTs) by the MWCNTs and europium nitrate (Eu(NO3)3•6H2O) on a mild conditions in the alkalescence solution. The influence of the different pH value on the product was analyzed. Characterizations of the products were performed using raman spectroscopy, X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), high resolution thermal field emission scanning electron microscopy (FE-SEM), and high resolution transmission electron microscopy (HR-TEM). Those results indicated that oxygen-containing groups such as -OH, -C=O, and -COOH generated on the surface of the MWCNTs treated with nitric acid. Those functional groups can attract Eu, and provide the position to Eu(OH)3. When the pH value situation of the reaction is 7-8, the MWCNTs deposited by Eu(OH)3 were obtained. Furthermore, there is the weak interaction between Eu and the functional groups of the MWCNTs. In addition, the integrity of the MWCNTs was not damaged during the whole preparation.





2008 ◽  
Vol 2 ◽  
pp. 77-84 ◽  
Author(s):  
U.S. Chen ◽  
Heng Yi Su ◽  
Chung Hao Wang ◽  
Han Chang Shih ◽  
Chien Te Hsieh ◽  
...  

Carbon nanotubes (CNTs) were functionalized using a simple method of heat treatment under oxygen atmosphere followed by an immersion in a tin nitrate aqueous solution. And well-dispersed SnOx nanodots were decorated on the surface of CNTs. X-ray photoelectron spectroscopy (XPS) analysis showed that the O/C ratio increases with oxygen-treated time. The distribution of carbon-containing functional groups on the CNTs surface, i.e., C−C, C−O, C=O, O−C=O, and π−π* shake up bonds can be identified and deconvoluted by a symmetrical Gauss function. The contact angle of H2O and CNTs is dependent on O/C ration. The relationships between the fraction of carbon-containing functional groups and various oxygen treatment times are also discussed.



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