Effect of Urea on the Shape and Structure of Carbon Nanotubes

2018 ◽  
Vol 73 (2) ◽  
pp. 113-120 ◽  
Author(s):  
M. R. Elamin ◽  
Babiker Y. Abdulkhair ◽  
Kamal K. Taha
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Chemical Vapour ◽  
Multiwall Carbon Nanotubes ◽  
Nitrogen Adsorption ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Adsorption Analysis ◽  
Bet Analysis ◽  
Multiwall Carbon

AbstractCoiled multiwall carbon nanotubes (MWCNTs) were prepared on Fe, Co, and Ni metal oxides supported on α-Al2O3 using urea as fuel and catalyst surface modifying agent by catalytic chemical vapour deposition (CCVD). The shape of the nanotubes was influenced by the addition of urea, where coiled and uncoiled tubes were obtained in the presence and absence of urea, respectively. The MWCNTs were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and nitrogen adsorption analysis. The coiling/uncoiling of the nanotubes was visualized from the SEM and TEM images of the prepared specimens. The XRD data showed the characteristic peaks of the nanotubes. BET analysis of the coiled tubes revealed 85.57 m2 g−1 surface area with a pore diameter 102.2–110.8 Å. A mechanism for the nanotubes coiling is suggested.

Stacking Faults in SiC Nanowires

2008 ◽  
Vol 8 (7) ◽  
pp. 3504-3510 ◽  
Author(s):  
K. L. Wallis ◽  
M. Wieligor ◽  
T. W. Zerda ◽  
S. Stelmakh ◽  
S. Gierlotka ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Stacking Faults ◽  
Multiwall Carbon Nanotubes ◽  
Structural Defects ◽  
X Ray Diffraction ◽  
Ir Spectrometry ◽  
X Ray ◽  
Sic Nanowires ◽  
Transmission Electron ◽  
Multiwall Carbon

SiC nanowires were obtained by a reaction between vapor silicon and multiwall carbon nanotubes, CNT, in vacuum at 1200 °C. Raman and IR spectrometry, X-ray diffraction and high resolution transmission electron microscopy, HRTEM, were used to characterize properties of SiC nanowires. Morphology and chemical composition of the nanowires was similar for all samples, but concentration of structural defects varied and depended on the origin of CNT. Stacking faults were characterized by HRTEM and Raman spectroscopy, and both techniques provided complementary results. Raman microscopy allowed studying structural defects inside individual nanowires. A thin layer of amorphous silicon carbide was detected on the surface of nanowires.

scholarly journals Effect of Carboxylic Functional Group Functionalized on Carbon Nanotubes Surface on the Removal of Lead from Water

2010 ◽  
Vol 2010 ◽  
pp. 1-9 ◽  
Author(s):  
Muataz Ali Atieh ◽  
Omer Yehya Bakather ◽  
Bassam Al-Tawbini ◽  
Alaadin A. Bukhari ◽  
Faraj Ahmad Abuilaiwi ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Functional Group ◽  
Multiwall Carbon Nanotubes ◽  
Chemical Properties ◽  
Average Diameter ◽  
Transmission Electron ◽  
Physical And Chemical ◽  
Multiwall Carbon ◽  
Carboxylic Functional Group

The adsorption mechanism of the removal of lead from water by using carboxylic functional group (COOH) functionalized on the surface of carbon nanotubes was investigated. Four independent variables including pH, CNTs dosage, contact time, and agitation speed were carried out to determine the influence of these parameters on the adsorption capacity of the lead from water. The morphology of the synthesized multiwall carbon nanotubes (MWCNTs) was characterized by using field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) in order to measure the diameter and the length of the CNTs. The diameters of the carbon nanotubes were varied from 20 to 40 nm with average diameter at 24 nm and 10 micrometer in length. Results of the study showed that 100% of lead was removed by using COOH-MCNTs at pH 7, 150 rpm, and 2 hours. These high removal efficiencies were likely attributed to the strong affinity of lead to the physical and chemical properties of the CNTs. The adsorption isotherms plots were well fitted with experimental data.

An Easy Methodology for the Incorporation of Carbon Nanotubes on Surfaces of Components Applied as Electronic Devices

2012 ◽  
Vol 18-19 ◽  
pp. 157-163
Author(s):  
M. Pérez-Cadenas ◽  
A. Maroto-Valiente ◽  
I. Rodríguez-Ramos ◽  
A. Guerrero-Ruíz
Keyword(s):  
Carbon Nanotubes ◽  
Photoelectron Spectroscopy ◽  
Iron Catalyst ◽  
Substrate Surface ◽  
Electronic Devices ◽  
Chemical Vapour ◽  
Multiwall Carbon Nanotubes ◽  
Transmission Electron ◽  
Vertically Aligned ◽  
Multiwall Carbon

Carbon nanotubes are grown by catalytic chemical vapour deposition over components of electronic devices. Samples are analyzed by thermogravimetry, scanning and transmission electron microscopy and X-ray photoelectron spectroscopy. The carbon materials deposited on the microchips present the morphology of multiwall carbon nanotubes and grow vertically aligned on the substrates. The preparation procedure parameters are changed to control sizes and height of the grown multiwall carbon nanotubes. The selectivity to incorporate, or not, carbon nanotubes depends on the chemical composition of the substrate. While carbon nanotubes are efficiently grown on Au surfaces, this reaction does not occur on Pt surfaces. These results correlate with a heterogeneous nucleation of iron catalyst particles on the substrate surface. The resulting composite materials can find numerous technological applications.

scholarly journals Composite Nanofibers Containing Multiwall Carbon Nanotubes as Biodegradable Membranes in Reconstructive Medicine

Nanomaterials ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 63 ◽  
Author(s):  
Andrzej Hudecki ◽  
Dorota Łyko-Morawska ◽  
Wirginia Likus ◽  
Magdalena Skonieczna ◽  
Jarosław Markowski ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Maxillofacial Surgery ◽  
Multiwall Carbon Nanotubes ◽  
Dermal Fibroblasts ◽  
Hydroxyl Groups ◽  
X Ray ◽  
Biological Responses ◽  
Transmission Electron ◽  
Multiwall Carbon

We have tested titanium (Ti) plates that are used for bone reconstruction in maxillofacial surgery, in combination with five types of novel long-resorbable biomaterials: (i) PCL0—polycaprolactone without additives, (ii) PCLMWCNT—polycaprolactone with the addition of multiwall carbon nanotubes (MWCNT), (iii) PCLOH—polycaprolactone doped with multiwall carbon nanotubes (MWCNT) containing –OH hydroxyl groups, (iv) PCLCOOH—polycaprolactone with the addition of multiwall carbon nanotubes (MWCNT) containing carboxyl groups, and (v) PCLTI—polycaprolactone with the addition of Ti nanoparticles. The structure and properties of the obtained materials have been examined with the use of Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), and/or X-ray powder diffraction (XRD). Titanium BR plates have been covered with: (i) PCL0 fibers (PCL0BR—connection plates), (ii) PCLMWCNT fibers (PCLMWCNTBR—plates), (iii) PCLOH fibers (PCLOHBR—plates), (iv) PCLCOOH (PCLCOOHBR—plates), (v) PCLTI fiber (PCLTIBR—connection plates). Such modified titanium plates were exposed to X-ray doses corresponding to those applied in head and neck tumor treatment. The potential leaching of toxic materials upon the irradiation of such modified titanium plates, and their effect on normal human dermal fibroblasts (NHDF) have been assessed by MTT assay. The presented results show variable biological responses depending on the modifications to titanium plates.

CHARACTERIZATION AND ELECTRICAL PROPERTIES OF ALIGNED CARBON NANOTUBES WITH HIGH ASPECT RATIO

2011 ◽  
Vol 10 (01n02) ◽  
pp. 23-28
Author(s):  
RAVI BHATIA ◽  
V. PRASAD ◽  
M. REGHU
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Aspect Ratio ◽  
Multiwall Carbon Nanotubes ◽  
High Quality ◽  
Transmission Electron Microscopy Analysis ◽  
Transmission Electron ◽  
Electron Microscopy Analysis ◽  
High Degree

High-quality multiwall carbon nanotubes (MWNTs) were produced by a simple one-step technique. The production of MWNTs was based on thermal decomposition of the mixture of a liquid phase organic compound and ferrocene. High degree of alignment was noticed by scanning electron microscopy. The aspect ratio of as-synthesized MWNTs was quite high (more than 4500). Transmission electron microscopy analysis showed the presence of the catalytic iron nanorods at various lengths of MWNTs. Raman spectroscopy was used to know the quality of MWNTs. The ratio of intensity of the G-peak to the D-peak was very high which revealed high quality of MWNTs. Magnetotransport studies were carried out at low temperature and a negative MR was noticed.

Synthesis and Photoluminescence Properties of Novel SnO2 Zigzag Nanoribbons

2010 ◽  
Vol 97-101 ◽  
pp. 4213-4216
Author(s):  
Jian Xiong Liu ◽  
Zheng Yu Wu ◽  
Guo Wen Meng ◽  
Zhao Lin Zhan
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Photoluminescence Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Ceramic Boat

Novel single-crystalline SnO2 zigzag nanoribbons have been successfully synthesized by chemical vapour deposition. Sn powder in a ceramic boat covered with Si plates was heated at 1100°C in a flowing argon atmosphere to get deposits on a Si wafers. The main part of deposits is SnO2 zigzag nanoribbons. They were characterized by means of X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM) and selected-area electron diffraction (SAED). SEM observations reveal that the SnO2 zigzag nanoribbons are almost uniform, with lengths near to several hundred micrometers and have a good periodically tuned microstructure as the same zigzag angle and growth directions. Possible growth mechanism of these zigzag nanoribbons was discussed. A room temperature PL spectrum of the zigzag nanoribbons shows three peaks at 373nm, 421nm and 477nm.The novel zigzag microstructures will provide a new candidate for potential application.

scholarly journals Free and partially encapsulated manganese ferrite nanoparticles in multiwall carbon nanotubes

2020 ◽  
Vol 11 ◽  
pp. 1891-1904
Author(s):  
Saja Al-Khabouri ◽  
Salim Al-Harthi ◽  
Toru Maekawa ◽  
Mohamed E Elzain ◽  
Ashraf Al-Hinai ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Multiwall Carbon Nanotubes ◽  
Ferrite Nanoparticles ◽  
Photoemission Spectroscopy ◽  
Manganese Ferrite ◽  
X Ray Diffraction ◽  
Band Emission ◽  
Structure Surface ◽  
Diffraction Peaks ◽  
Multiwall Carbon

Free and partially encapsulated manganese ferrite (MnFe2O4) nanoparticles are synthesized and characterized regarding structure, surface, and electronic and magnetic properties. The preparation method of partially encapsulated manganese ferrite enables the formation of a hybrid nanoparticle/tube system, which exhibits properties of manganese ferrite nanoparticles inside and attached to the external surface of the tubes. The effect of having manganese ferrite nanoparticles inside the tubes is observed as a shift in the X-ray diffraction peaks and as an increase in stress, hyperfine field, and coercivity when compared to free manganese ferrite nanoparticles. On the other hand, a strong charge transfer from the multiwall carbon nanotubes is attributed to the attachment of manganese ferrite nanoparticles outside the tubes, which is detected by a significant decrease in the σ band emission of the ultraviolet photoemission spectroscopy signal. This is followed by an increase in the density of states at the Fermi level of the attached manganese ferrite nanoparticles in comparison to free manganese ferrite nanoparticles, which leads to an enhancement of the metallic properties.

Sonochemistry: a good, fast and clean method to promote the removal of Cu(ii) and Cr(vi) by MWCNT/CoFe2O4@PEI nanocomposites: optimization study

2018 ◽  
Vol 42 (19) ◽  
pp. 16307-16328 ◽  
Author(s):  
Mohammad Hassan Omidi ◽  
Mohammad Hossein Ahmadi Azqhandi ◽  
Bahram Ghalami-Choobar
Keyword(s):  
Electron Microscopy ◽  
X Ray Diffraction ◽  
Multiwalled Carbon ◽  
X Ray ◽  
Transmission Electron ◽  
Optimization Study ◽  
Bet Analysis ◽  
Branched Polyethylenimine ◽  
Magnetic Multiwalled Carbon Nanotubes ◽  
Scanning Electron

In this study, branched polyethylenimine (PEI) loaded on magnetic multiwalled carbon nanotubes (MWCNT/CoFe2O4) was synthesized and characterized by transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) analysis and Fourier transform infrared spectroscopy (FTIR).

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