VERTICALLY ALIGNED CARBON NANOTUBES AT DIFFERENT TEMPERATURES BY SPRAY PYROLYSIS TECHNIQUES

2006 ◽  
Vol 20 (29) ◽  
pp. 4965-4972 ◽  
Author(s):  
RAKESH A. AFRE ◽  
T. SOGA ◽  
T. JIMBO ◽  
MUKUL KUMAR ◽  
Y. ANDO ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Spray Pyrolysis ◽  
Morphological Characteristics ◽  
Catalyst Precursor ◽  
Simple Method ◽  
Fe Catalyst ◽  
Different Temperatures ◽  
Multi Walled Carbon Nanotubes ◽  
Vertically Aligned ◽  
Walled Carbon Nanotubes

Vertically aligned arrays of multi-walled carbon nanotubes (VACNTs) were grown by spray pyrolysis of turpentine oil and ferrocene mixture at temperatures higher than 700°C. Using this simple method, we report the successful growth of vertically aligned nanotubes of ~300μm length and diameter in the range of ?20–80 nm on Si (100) substrate. The ferrocene acts as an in situ Fe catalyst precursor, forming the nano-sized metallic iron particles for formation of VACNTs on the Si substrate. The morphological characteristics of VACNTs are confirmed by SEM, TEM and Raman spectroscopy and growth mechanism is discussed in short.

The Effect of Calcination on Multi-Walled Carbon Nanotubes Produced by Dc-Arc Discharge

2008 ◽  
Vol 8 (7) ◽  
pp. 3539-3544 ◽  
Author(s):  
Sreejarani K. Pillai ◽  
Willem G. Augustyn ◽  
Margaretha H. Rossouw ◽  
Robert I. McCrindle
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Structural Integrity ◽  
Arc Discharge ◽  
Simple Method ◽  
Helium Atmosphere ◽  
Different Temperatures ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Dc Arc

Multi-walled carbon nanotubes were synthesized by dc-arc discharge in helium atmosphere and the effect of calcination at different temperatures ranging from 300–600 °C was studied in detail. The degree of degradation to the structural integrity of the multi-walled carbon nanotubes during the thermal process was studied by Raman spectroscopy, Scanning electron microscopy and High resolution transmission electron microscopy. The thermal behaviour of the as prepared and calcined samples was investigated by thermogravimetric analysis. Calcination in air at 400 °C for 2 hours was found to be an efficient and simple method to eliminate carbonaceous impurities from the nanotube bundles with minimal damage to the tube walls and length. The impurities were oxidized at a faster rate when compared to the nanotubes and gave good yield of about 50%. The nanotubes were observed to be damaged at temperature higher than 450 °C. The results show that this method is less destructive when compared liquid phase oxidation with 5 M HNO3.

Kinetics and thermodynamics of the sorption of furaltadone from aqueous solutions on magnetic multi-walled carbon nanotubes

2014 ◽  
Vol 70 (6) ◽  
pp. 964-971
Author(s):  
Xu Chen ◽  
Zhen-hu Xiong
Keyword(s):  
Carbon Nanotubes ◽  
Aqueous Solutions ◽  
Sorption Data ◽  
Multi Wall Carbon Nanotubes ◽  
Adsorption Behaviors ◽  
Different Temperatures ◽  
Multi Walled Carbon Nanotubes ◽  
Pseudo Second Order ◽  
Experimental Data Analysis ◽  
Walled Carbon Nanotubes

Magnetic multi-wall carbon nanotubes (M-MWCNTs) were used as an adsorbent for removal of furaltadone from aqueous solutions, and the adsorption behaviors were investigated by varying pH, sorbent amount, sorption time and temperature. The results showed that the adsorption efficiency of furaltadone reached 97% when the dosage of M-MWCNT was 0.45 g · L−1, the pH was 7 and the adsorption time was 150 min. The kinetic data showed that the pseudo-second-order model can fit the adsorption kinetics. The sorption data could be well explained by the Langmuir model under different temperatures. The adsorption process was influenced by both intraparticle diffusion and external mass transfer. The experimental data analysis indicated that the electrostatic attraction and π–π stacking interactions between M-MWCNT and furaltadone might be the adsorption mechanism. Thermodynamic analysis reflected that adsorption of furaltadone on the M-MWCNT was spontaneous and exothermic. Our study showed that M-MWCNTs can be used as a potential adsorbent for removal of furaltadone from water and wastewater.

scholarly journals PRELIMINARY STUDY OF ELECTROPHORETIC DEPOSITION OF VERTICALLY ALIGNED MWCNT ON METALLIC ELECTRODE

2012 ◽  
Vol 05 ◽  
pp. 704-711
Author(s):  
SIAVASH KHABAZIAN ◽  
SOHRAB SANJABI
Keyword(s):  
Carbon Nanotubes ◽  
Metallic Electrode ◽  
Aqueous Solvent ◽  
Multi Walled Carbon Nanotubes ◽  
Dc Electric Field ◽  
Ft Ir ◽  
Vertically Aligned ◽  
Preliminary Study ◽  
Walled Carbon Nanotubes ◽  
Scanning Electron

Multi-walled carbon nanotubes films formed randomly aligned laterally by electrophoresis. Multi-walled carbon nanotubes with lengths of about 10 μ was shortened and functionalized by a mixture of sulfuric and nitric acid. The functional groups on carbon nanotubes were elaborated by FT-IR. Chemically shortened MWCNTs disperse in organic and aqueous solvent and deposited on electrode vertically-aligned by applying a constant DC electric field. The alignment of MWCNTs was observed by scanning electron microscopy. It also the effect of various substrates on alignment of multi-walled carbon nanotubes was investigated.

scholarly journals Impact of Synthesis Parameters of Multi-Walled Carbon Nanotubes on their Thermoelectric Properties

Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3567 ◽  
Author(s):  
Bogumiła Kumanek ◽  
Grzegorz Stando ◽  
Paweł S. Wróbel ◽  
Dawid Janas
Keyword(s):  
Carbon Nanotubes ◽  
Thermoelectric Properties ◽  
Synthesis Temperature ◽  
Injection Rate ◽  
Optimum Synthesis ◽  
Synthesis Parameters ◽  
Different Temperatures ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
The Impact

Carbon nanotubes have been intensively researched for many years because of a wide array of promising properties that they have. In this paper, we present the impact of synthesis parameters on thermoelectric properties of nanocarbon material. We conducted a number of syntheses of multi-walled carbon nanotubes (MWCNTs) at different temperatures (800 and 900 °C) using various amounts of catalyst (2%, 5.5%, and 9.6%) to facilitate the process. We also tested the influence of injection rate of precursor and the necessity of material purification on thermoelectric properties of MWCNTs. The electrical conductivity, thermal conductivity, and Seebeck coefficient were measurement for all samples. Based on these parameters, the values of Power Factor and Figure of Merit were calculated. The results show that the most important parameter in the context of thermoelectric properties is purity of employed MWCNTs. To obtain appropriate material for this purpose optimum synthesis temperature and appropriate content of the catalyst must be selected. The study also reveals that post-synthetic purification of nanocarbon is essential to produce an attractive material for thermoelectrics.

scholarly journals Conjugated polyelectrolyte nano field emission adlayers

2016 ◽  
Vol 1 (4) ◽  
pp. 304-312 ◽  
Author(s):  
M. T. Cole ◽  
R. J. Parmee ◽  
A. Kumar ◽  
C. M. Collins ◽  
M. H. Kang ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Field Emission ◽  
Electron Emission ◽  
Field Electron Emission ◽  
Conjugated Polyelectrolyte ◽  
Emission Performance ◽  
Field Electron ◽  
Multi Walled Carbon Nanotubes ◽  
Vertically Aligned ◽  
Walled Carbon Nanotubes

Here we report on a straightforward and rapid means of enhancing the field electron emission performance of nascent vertically aligned multi-walled carbon nanotubes by introducing a polar zwitterionic conjugated polyelectrolyte adlayer at the vacuum–emitter interface.

Effect of Ferrocene Catalyst and Hydrogen Feed on Microstructures of Vertically Aligned MWCNTs

2016 ◽  
Vol 701 ◽  
pp. 8-12
Author(s):  
Shazia Shukrullah ◽  
Norani Muti Mohamed ◽  
Maizatul Shima Shaharun ◽  
Muhammad Yasar
Keyword(s):  
Carbon Nanotubes ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Areal Density ◽  
Optimum Conditions ◽  
Catalyst Amount ◽  
Multi Walled Carbon Nanotubes ◽  
Cvd Growth ◽  
Vertically Aligned ◽  
Walled Carbon Nanotubes

This study investigated the effect of catalyst amount on chemical vapour deposition (CVD) growth of multi-walled carbon nanotubes (MWCNTs) with and without hydrogen feed. The ferrocene weight was varied from 100 mg to 200 mg for CNTs growth over Si/SiO2/Al2O3 substrate. Very few CNTs were seen in micrographs of the samples produced in the absence of the hydrogen feed. Most of the carbon atoms precipitated into amorphous carbon due to existence of inactive catalyst particles. However, CNT structures grown with hydrogen feed were more distinct; the nanotubes were thinner, straight and highly crystalline. MWCNTs arrays/forest length was also increased from 120 µm to 850 µm with hydrogen feed. An increase in catalyst weight significantly affected the diameter, crystallinity, alignment and growth of nanotubes. The lowest inner-shell spacing of 0.348 nm was obtained with 150 mg of ferrocene, which is an indication of growth of relatively pure CNTs. Under the optimum conditions, the areal density of the ferrocene particles was sufficiently increased to get required alignment and crystallinity of MWCNTs.

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