A Study on the Effect of Calcination Temperature on the Graphitization of Carbon Nanotubes Synthesized by the Decomposition of Methane

2013 ◽  
Vol 832 ◽  
pp. 56-61 ◽  
Author(s):  
Wei Wen Liu ◽  
Tijjani Adam ◽  
Azizan Aziz ◽  
Siang Piao Chai ◽  
Abdul Rahman Mohamed ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Calcination Temperature ◽  
Catalytic Decomposition ◽  
Average Diameter ◽  
Calcination Temperatures ◽  
Transmission Electron ◽  
Different Temperatures ◽  
Decomposition Of Methane

The effect of calcination temperature for Fe2O3/MgO catalysts on the formation of carbon nanotubes (CNTs) was examined. CNTs were synthesized over Fe2O3/MgO catalysts calcined at different temperatures by catalytic decomposition of methane at 1000°C. The synthesized CNTs were investigated by a combination of scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and Raman spectroscopy. The results show that the effect of calcination temperatures greatly governed the diameter and the quality of the SWCNTs formed. The catalysts calcined at 500, 600 and 700°C produced CNTswith the diameters of 1.53, 1.95 and 2.97nm, respectively. Generally, an increase in the calcination temperature increases the average diameter and decreases the quality of the CNTs produced.

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.

Effect of Catalyst Calcination Temperature on the Synthesis of MWCNTs-Talc Hybrid Compound Using CVD Method

2013 ◽  
Vol 594-595 ◽  
pp. 63-67
Author(s):  
Siti Shuhadah Mohd Saleh ◽  
Hazizan Md Akil ◽  
Ramdziah Md. Nasir ◽  
Muhammad Razlan Zakaria ◽  
Muhammad Helmi Abdul Kudus
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Source ◽  
Calcination Temperature ◽  
Chemical Vapour ◽  
Catalytic Decomposition ◽  
Metal Catalyst ◽  
Hybrid Compound ◽  
Calcination Temperatures ◽  
Cvd Method ◽  
Multi Walled Carbon Nanotubes

Carbon nanotubes-talc (CNTs-talc) hybrid compound has been successfully synthesized via chemical vapour deposition (CVD) method. A gas mixture of methane/nitrogen (CH4/N2) was used as the carbon source and nickel as the metal catalyst for the growth of CNT hybrid compound. Talc works as substrate or support material which is combined with nickel to form a complex metal-talc catalyst that will react with carbon source to produce the hybrid compound. To study the effect of different calcinations temperature, four different calcinations temperature, 300 °C (C-talc300), 500 °C (C-talc500), 700 °C (C-talc700) and 900 °C (C-talc900) were used. Among these four calcination temperatures for synthesis the multi-walled carbon nanotubes (MWCNTs), C-talc500 is the most optimum calcination temperature to perform catalytic decomposition by reacting in methane atmosphere at 800 °C to produce the CNT-talc hybrid compound.

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.

scholarly journals Luminescence properties of Eu3+ activated Y2MoO6 powders calcined at different temperatures

2020 ◽  
Vol 14 (1) ◽  
pp. 71-76 ◽  
Author(s):  
Nadezda Stankovic ◽  
Marko Nikolic ◽  
Branislav Jelenkovic ◽  
Nina Daneu ◽  
Jelena Maletaskic ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
X Ray Diffraction ◽  
Light Emitting ◽  
White Leds ◽  
Calcination Temperatures ◽  
Transmission Electron ◽  
Light Region ◽  
Lower Treatment ◽  
Different Temperatures ◽  
White Light Emitting Diodes

In the last decade, an immense progress has been made in white LEDs, mainly due to the development of red-emitting phosphors. In this paper, we report on the synthesis of Eu3+ activated Y2MoO6 by a self-initiated and self-sustained method. The obtained powder was calcined at various temperatures in the 600-1400?C range and examined by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and photoluminescence spectroscopy (PL). The results revealed that all powders are single phase Y2MoO6:Eu3+, with particle size in the nanorange at lower treatment temperatures (600 and 800?C) and in the microrange at higher calcination temperatures (1000-1400?C). The obtained powders are promising materials for white light-emitting diodes as they can efficiently absorb energy in 324-425 nm region (near-UV to blue light region) and emit at 611 nm in the red region of the spectrum, while exhibiting high thermal and chemical stability.

Structure and Field Electron Emission of Carbon Nanotubes Dependent on Growth Temperature

2002 ◽  
Vol 728 ◽  
Author(s):  
Yoon Huh ◽  
Jeong Yong Lee ◽  
Tae Jae Lee ◽  
Seung Chul Lyu ◽  
Cheol Jin Lee
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Growth Rate ◽  
Growth Temperature ◽  
Silicon Oxide ◽  
Structural Characteristics ◽  
Average Diameter ◽  
Crystalline Perfection ◽  
Thermal Cvd ◽  
Transmission Electron

AbstractThis present work deals with the temperature dependence on the growth and structure of CNTs grown by thermal CVD. The vertically aligned CNTs are synthesized on iron (Fe)-deposited silicon oxide (SiO2) substrate by thermal CVD using acetylene gas at temperatures in the range 750-950°C. Configuration and structural characteristics of CNTs have been investigated using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). As the growth temperature increases from 750 to 950°C, the growth rate and the average diameter increase while the density decreases by a factor of about 2. TEM images show that the relative amount of crystalline graphitic sheets increases with increasing the growth temperature and a higher degree of crystalline perfection can be achieved at 950°C. The HRTEM images reveal consistently that the degree of crystalline perfection increases progressively as the growth temperature increases. This result demonstrates that the growth rate, diameter, density, and crystallinity of carbon nanotubes can be controlled with the growth temperature.

Optical Absorption and Photoconversion Characteristics of WO3 Nanofiber Photoanodes Prepared by Electrospinning with Different Calcination Temperatures

2021 ◽  
Vol 324 ◽  
pp. 103-108
Author(s):  
Ratchaneekorn Bojarus ◽  
Tienthong Yuangkaew ◽  
Thawach Thammabut ◽  
Mati Horprathum ◽  
Papot Jaroenapibal ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
High Performance ◽  
Optical Band Gap ◽  
Linear Sweep Voltammetry ◽  
Band Gap Energy ◽  
Linear Sweep ◽  
Calcination Temperatures ◽  
Oxide Electrodes ◽  
Transmission Electron ◽  
Different Temperatures

This study aims to synthesize and examine the optical and photoelectrochemical properties of tungsten oxide (WO3) nanofibers prepared by electrospinning and calcination using different temperatures (500, 700, and 900 °C). The electrospinning solution contained a mixture of polyvinyl alcohol (PVA, 7.5% w/v) and ammonium metatungstate hydrate (AMH, 16.7% w/v). The morphology of WO3 nanofibers was observed via scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The absorbance of calcined WO3 nanofibers was measured, and the data was used to calculate the optical band gap energy (Eg) through Tauc’s relation. The of calcined WO3 nanofibers were found to be from 2.85 to 3.08 eV. The minimum value of was obtained from the sample calcined at 900 °C. Linear sweep voltammetry (LSV) was employed in the photocurrent measurements under simulated AM 1.5G at 100 mW/cm2 irradiance. The WO3 nanofiber photoanode calcined at 900 °C exhibited the maximum photoconversion efficiency (PCE) of 1.53%, a twice enhancement in PCE compared with those obtained from WO3 nanofibers calcined at lower temperatures. This study suggests the potential pathway for the optimal synthesis of high performance nanostructured metal oxide electrodes for photoelectrochemical water splitting.

A New Ion Beam Deposition Technique for Low Temperature Silicon Epitaxy

1995 ◽  
Vol 388 ◽  
Author(s):  
S. Mohajerzadeh ◽  
C.R. Selvakumar ◽  
D.E. Brodie ◽  
M.D. Robertson ◽  
J.M. Corbett
Keyword(s):  
Electron Microscopy ◽  
Ion Beam ◽  
Island Growth ◽  
Si Substrates ◽  
Silicon Epitaxy ◽  
Transmission Electron ◽  
Different Temperatures ◽  
Si Films ◽  
Substrate Temperatures

AbstractWe report the results of an investigation to grow thin Si films on Si substrates at low substrate temperatures using ionized SiH4 gas generated with a Kaufman type ion gun. This investigation shows island-growth at higher substrate temperatures (500-700°C) in the form of square-based pyramids. by lowering the substrate temperature to 300°C, we were able to achieve a planar growth. the growth rate can be enhanced by introducing elemental Si from a thermal evaporation source. Scanning electron microscopy, transmission electron microscopy and electron diffraction analysis were used to study the crystalline quality of the samples prepared at different temperatures.

Tem Study of Temperature Influence on The Crystalline Quality of InGaAs/Si Epilayers

1992 ◽  
Vol 263 ◽  
Author(s):  
A. Vila ◽  
A. Cornet ◽  
J.R. Morante ◽  
D.I. Westwood
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Molecular Beam ◽  
Temperature Influence ◽  
X Ray Diffraction ◽  
Double Crystal ◽  
X Ray ◽  
Transmission Electron ◽  
Different Temperatures

ABSTRACTA Transmission Electron Microscopy (TEM) study of In0.53Ga0.47As Molecular Beam Epitaxy films grown at different temperatures onto misoriented Si (100) substrates is presented. The evolution of the density of the different kind of defects is discussed as a function of the growth temperature in the range between 200 and 500° C. The results are compared with the characterization techniques of Double Crystal X-Ray Diffraction and Hall effect.

scholarly journals Carbide Nanoparticles Encapsulated in the Caves of Carbon Nanotubes by an In Situ Reduction-Carbonization Route

2011 ◽  
Vol 2011 ◽  
pp. 1-5 ◽  
Author(s):  
Chunli Guo ◽  
Yitai Qian ◽  
Pengju Han
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Average Diameter ◽  
Structural Features ◽  
Metal Catalyst ◽  
In Situ Reduction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron

Carbides (TiC, WC, and NbC) nanoparticles fully encapsulated in the caves of carbon nanotubes (CNTs) were synthesized via an in situ reduction-carbonization route at 600∘C in an autoclave. The structural features and morphologies of as-obtained products were investigated using by X-ray diffraction, scanning electron microscopy, and high-resolution transmission electron microscopy (HRTEM). HRTEM studies showed that the average diameter of CNTs encapsulated with carbide nanoparticles are in the range of 15–40 nm. The reaction temperature, the reaction time, and the metal catalyst are found to play crucial roles to the product morphology. The growth mechanism of carbide nanoparticles encapsulated in CNTs was discussed in detail.

scholarly journals Microscopy and Spectroscopy Characterization of Carbon Nanotubes Grown at Different Temperatures Using Cyclohexanol as Carbon Source

2019 ◽  
Vol 2019 ◽  
pp. 1-6
Author(s):  
Elsa G. Ordoñez Casanova ◽  
Héctor A. Trejo Mandujano ◽  
Manuel Román Aguirre
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Carbon Source ◽  
Morphological Changes ◽  
Spray Pyrolysis Technique ◽  
Product Yield ◽  
Structural Morphology ◽  
Transmission Electron ◽  
Different Temperatures

We present the structural and spectroscopy characterization of carbon nanotubes (CNTs) grown by the spray pyrolysis technique, using ferrocene as catalyzer and cyclohexanol as the carbon source, and synthetized in a temperature range of 750 to 1000°C. The structural morphology was observed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The spectroscopy response was obtained by UV-Vis and Raman spectroscopy. We observed morphological changes and found that the product yield seems to increase with temperature. The optical characterization corroborated the presence of n – π∗ transitions and Van Hove singularities as result of possible electrical conductivity changes.

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