- Email: [email protected]
Preparation and study of the electrical, magnetic and thermal properties of Fe3O4 coated carbon nanotubes
Accepted Manuscript
Preparation and study of the electrical, magnetic and thermal properties of Fe3 O4 coated carbon nanotubes Mohammad Hassan Ramezan zadeh , Majid Seifi , Hoda Hekmatara , Mohammad Bagher Askari PII: DOI: Reference:
S0577-9073(17)30520-8 10.1016/j.cjph.2017.06.011 CJPH 297
To appear in:
Chinese Journal of Physics
Received date: Revised date: Accepted date:
30 April 2017 19 June 2017 27 June 2017
Please cite this article as: Mohammad Hassan Ramezan zadeh , Majid Seifi , Hoda Hekmatara , Mohammad Bagher Askari , Preparation and study of the electrical, magnetic and thermal properties of Fe3 O4 coated carbon nanotubes, Chinese Journal of Physics (2017), doi: 10.1016/j.cjph.2017.06.011
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
ACCEPTED MANUSCRIPT
Highlights
AC
CE
PT
ED
M
AN US
CR IP T
MWCNTs were coated with Fe3O4 nanoparticles using a wet chemical method. The TEM micrograph represented the well-established microstructure Fe3O4/MWCNTs. Improvements in the electrical and thermal conductivity of MWCNTs were observed. The Fe3O4/MWCNTs nanocomposites showed a superparamagnetic behavior.
1
of
ACCEPTED MANUSCRIPT
Preparation and study of the electrical, magnetic and thermal properties of Fe3O4 coated carbon nanotubes Mohammad Hassan Ramezan zadeh a, Majid Seifi a , *, Hoda Hekmatara b, Mohammad Bagher Askari a , c ,* a
CR IP T
Department of Physics, Faculty of Science, University of Guilan, Rasht 41335, Iran Department of Physics, Vali-e-Asr University of Rafsanjan, Iran c Department of Physics, Payame Noor University, PO Box 19395-3697 Tehran, Iran b
AN US
Corresponding author: Majid Seifi & Mohammad Bagher Askari Department of Physics, Faculty of Science, University of Guilan, Rasht 41335, Iran m_seifi2000@ yahoo.com (Majid Seifi) [email protected] (Mohammad Bagher Askari)
M
Abstract
ED
In this work, functionalized multiwalled carbon nanotubes (f-MWCNTs) were coated with Fe3O4 nanoparticles using a straightforward wet chemical method. The obtained magnetic nanocomposites were characterized by using Fourier transform
PT
infrared (FTIR) and X-ray diffraction (XRD) spectroscopies to investigate the
CE
chemical bonds and structures. Transmission electron microscopy (TEM) revealed the microstructure of the iron oxide coated MWCNTs. The electrical resistivity of
AC
pristine, functionalized, and MWCNT/Fe3O4 nanocomposites were measured by the two-probe method. The results showed that the electrical resistivity of the carbon nanotubes was decreased by the chemical functionalization and decoration with Fe3O4 nanoparticles. It was also observed that with increasing the applied voltage the resistivity of all the samples increased. Magnetic characterization showed a superparamagnetic behavior for the synthesized MWCNT/Fe3O4 nanocomposites. 2
ACCEPTED MANUSCRIPT
Thermal conductivity measurements of the samples in water showed that the functionalization of nanotubes decreased the thermal conductivity of water, but decorating the carbon nanotubes by magnetic nanoparticles increased the thermal conductivity of water.
CR IP T
Keywords: Carbon nanotubes; Fe3O4 nanoparticles; thermal properties; electrical properties; magnetic properties.
1. Introduction
AN US
Carbon nanotubes are important materials because of their electronic, magnetic and gas adsorption properties [1]. In order to make devices based on nanotubes with better properties and efficiencies, different ways have been offered and attempted [2]. Up to the present, some routes have been reported for coating carbon
M
nanotubes, such as electroless plating methods [3, 4], physical vapor deposition [5], atomic-layer deposition [6], and so on [7, 8]. Moreover, carbon nanotubes have
ED
extensive applications in catalysts, sensors, semiconductor devices and new booster materials. In addition, iron oxide nanoparticles are significant materials as effective
PT
catalysts. It is expected that the exposure of iron oxide nanoparticles on the surface of some one-dimensional materials, such as carbon nanotubes, will cause a more
CE
intense modification of the magnetic and catalytic properties of the onedimensional structure, because of the interaction between the iron oxide and the
AC
CNTs [9, 10]. Up to the present, different types of MWCNTs have been coated by Ni [11], Co [12], CoO [13], Fe [14], etc., but, iron oxide nanoparticles (such as maghemite and magnetite) have been under special investigation because of their low
toxicity,
stability,
and
biocompatibility
properties
in
physiological
environments [15-17]. In order to combine the benefits of MWCNTs and iron oxide nanoparticles, different routes have been used. 3
ACCEPTED MANUSCRIPT
2. Experiment 2.1. Materials MWCNTs with diameters and lengths ranging between 20-40 nm and 5-15 μm, respectively, and a minimum purity of 95% were purchased from Shenzhen
CR IP T
Nanotech Port Co. Ltd. Other raw materials including FeCl2.4H2O (Purity: 99.99%), FeCl3.6H2O (Purity: 98%), H2SO4 (95-98%), HNO3 (≥65%), and NaOH (≥97%) were purchased from Sigma Aldrich, Inc. 2.2. Functionalization of nanotubes
AN US
To functionalize the carbon nanotubes, 2 g of pristine MWCNTs were dispersed in 32 mL of the solution of H2SO4 and HNO3 (3/1) into a reaction flask. They were refluxed at 60 oC for 3 h. The mixture was cooled and diluted by distilled water. After that the mixture was dehydrated using a filter paper so that the remaining
M
water was removed, and then distilled water was added to it again. This work was constantly continued until the pH of the sample approached neutral magnitude.
ED
Finally, the sample was dried at 60 oC overnight until the sample became like black powder.
PT
2.3. Synthesis of MWCNT/Fe3O4 nanohybrid materials
CE
First 0.02 g of functionalized MWCNTs, 0.024 g of FeCl3.6H2O and 0.009 g of FeCl2.4H2O were put in a 100 mL balloon. Then 20 mL of nitric acid was added to
AC
this [18]. Next, the balloon was put under the frequency of 59 kHz in an ultrasonic device for 30 minutes. In the following step, in order to do reflux, the balloon was put into an oil bath at 120 oC for 4.5 h. Then the balloon was brought out from the container of oil. After the sample cooled, NaOH was added dropwise to it until neutral pH was achieved. In this stage, the mixture was poured over a micro membrane and deionized water was poured over the material several times. Then,
4
ACCEPTED MANUSCRIPT
the mixture was centrifuged several times in deionized water. After that the sample was dried at 100 oC for 2 h and then calcinated at 200 oC for 2 hours. 2.4. Characterizations Phase identification was carried out using a Holland Philips Xpert X-ray powder BRUKER®TENSOR27 in the range of 400-4000 cm-1.
CR IP T
diffraction (XRD) diffractometer with CuKα radiation (λ=0.15406 nm), and a
A JEOL JEM-2010 transmission electron microscope (TEM) at an accelerating voltage of 200 kV was used to determine and confirm the presence of nanoparticles
AN US
on the nanotube’s surfaces and the diameter of the nanotubes.
Electrical measurements of the sample were done by the two-probe method. The circuit included just a loop having a constant 10 kΩ resistor and the sample as the second one.
M
Magnetic properties of the nanocomposites were characterized by a vibrating sample magnetometer (VSM, Lakeshore7407) at room temperature.
ED
Thermal conductivity including the velocity field measurements were done by a three dimensional traversing hot-wire system installed by the Fara Sanjesh Saba
PT
(FSS) Company.
CE
3. Results and discussion
AC
3.1. Fourier transform infrared (FTIR) spectroscopy The structural and lattice constants of magnetite (Fe3O4) and maghemite (γ-
Fe2O3) are similar (0.8350 nm for maghemite and 0.8396 for magnetite), and both of them have a spinel-type structure. Hence, the identification of maghemite and magnetite from the XRD pattern is not readily possible [19]. A direct evidence is required to identify the crystal structure. Fig. 1 shows the FTIR spectra of pristine 5
ACCEPTED MANUSCRIPT
MWCNTs and MWCNT/ Fe3O4 nanocomposites. In comparison with the pristine MWCNTs’ spectrum in Fig. 1a, there is a peak at 570 cm-1 in Fig. 1b that can be ascribed to the existence of the stretching bonds of the Fe-O in tetrahedral and octahedral structures that is related to magnetite. In the case of maghemite the status is different, and there is a peak at 630 cm-1 [20]. The signals of 1630 cm-1 and
CR IP T
3430 cm-1 are related to the functionalized groups of carbonyl (1626 cm-1) and
CE
PT
ED
M
AN US
hydroxyl (3424 cm-1) attached to MWCNT, respectively [21].
AC
Fig. 1. FTIR spectra of (a) pristine MWCNTs, (b) MWCNTs coated with magnetite nanoparticles.
3.2. XRD pattern of the sample and its interpretation Fig. 2 shows a peak around 2θ=26o, which is a characteristic peak of graphite and is related to pristine MWCNTs. As shown in Fig. 3, regarding the diffraction 6
ACCEPTED MANUSCRIPT
patterns [19, 22], a strong peak around 2θ=26o is related to the reflection of (0 0 2) for graphite, and other peaks are related to magnetite with the reflections of a standard FCC (1 1 1), (2 2 0), (3 1 1), (4 0 0), (4 2 2), (5 1 1) and (4 4 0). In the following, Table 1 is related to the magnitudes of FWHM (full width at half
CR IP T
maximum) and height attributed to the important peaks of coated carbon nanotubes with iron oxide nanoparticles. It contains also the crystallite size of the iron oxide nanoparticles at important peaks calculated by the Scherrer equation [23]: ,
(1)
AC
CE
PT
ED
M
AN US
In relation (1), D represents the crystallite size, θ is the Bragg angle and β shows the amount of FWHM (full width at half maximum). Also, λ is used to represent the wavelength of copper radiation (1.54 Å). The average magnetite grain size ( ̅ ) is around 6 nm.
Fig. 2. XRD pattern of f-MWCNTs.
7
AN US
CR IP T
ACCEPTED MANUSCRIPT
M
Fig. 3. XRD pattern of MWCNT/Fe3O4 nanocomposites.
Table 1
ED
The estimated grain sizes of magnetite nanoparticles in MWCNT/Fe3O4 nanocomposites. Height
FWHM
D
̅
(counts)
(radian)
(nm)
(nm)
(2 2 0)
47
0.2362
6
6
(3 1 1)
136
0.4723
3
(4 0 0)
75
0.3936
4
(4 2 2)
65
0.2362
7
58
(5 1 1)
93
0.1940
8
63
(4 4 0)
113
0.2362
7
2θ (degree) 30
46
AC
54
CE
38
PT
hkl
3.3. Transmission electron microscopy (TEM) Fig. 4 is related to the TEM micrograph of carbon nanotubes coated with magnetite. It shows long nanotubes with diameters between 20 and 40 nm, which is 8
ACCEPTED MANUSCRIPT
a validation for the factory’s information about the purchased products. In addition, black spots in the intervals of 3 to 15 nm are magnetite nanoparticles that are attached to the outer surfaces of the nanotube’s body. This range of grain size is smaller than the superparamagnetic critical size of magnetite nanoparticles, which
PT
ED
M
AN US
CR IP T
is almost 20 nm [24].
CE
Fig. 4. TEM micrograph of carbon nanotubes coated with iron oxide nanoparticles.
AC
3.4. Measurement of electrical conductivity
In order to measure the electrical conductivity of materials, different ways have
been proposed. Because the sample is a powder, the two-wire method was used. In this method, the powders were compressed and put between two wires in a circuit using a capillary tube. By creating an appropriate electrical circuit, the DC conductivity of pristine, the functionalized and coated MWCNTs were analyzed. In 9
ACCEPTED MANUSCRIPT
order to determine the electrical resistance of the powder samples, they were put into incombustible insulators that were cylindrical with a radius of 2 mm and length of 5 mm. From the two sides of the tube, suitable metallic wires were in full contact with the samples. The voltage of the power supply was increased. This
CR IP T
way, the voltage of the two heads of the sample and also the current passing into the circuit can be noted. Fig. 5 shows the schematic plan of the sample as a DC circuit. In order not to have a short contact in the circuit, another resistance was successively put in the circuit. Table 2 shows the magnitudes of the electrical
AC
CE
PT
ED
M
AN US
current at different voltages of the two heads of the samples.
Fig. 5. Schematic plan of exposure of the powder samples in a DC circuit.
10
ACCEPTED MANUSCRIPT
Table 2 Magnitudes of the electric current at different voltages of the two heads of the samples.
The electrical current (functionalized MWCNTs) (A)
0 0.1 0.2 0.5 1 2 3 4 5 6 7
0 0.0005 0.0015 0.09 0.21 0.46 0.7 0.96 1.28 1.85 2.2
0 0.0004 0.001 0.014 0.23 0.44 0.63 0.74 0.87 1.02 1.15
The electrical current (Fe3O4 coated MWCNTs) (A)
CR IP T
Electrical Current (pristine MWCNTs) (A)
0 0.0003 0.003 0.02 0.05 0.15 0.28 0.34 0.44 0.59 0.71
ED
M
AN US
The voltage of two ends of sample (v)
Fig. 6 shows the I-V diagram of the pristine, functionalized and coated nanotubes.
PT
At low voltages, the behavior of the samples is linear (ohmic). At higher voltages, nonlinear (non-ohmic) behavior is seen, because of the increasing temperature and
CE
creating a tunneling current. The electric resistance of the functionalized nanotubes is larger than that of the pristine one, which is because of the creation of pentagon
AC
and heptagon holes on the nanotubes during the acid treatment. These holes cause scattering of the electrons and a decrease in the electric current. The largest magnitude of electric resistance is related to the coated nanotubes with iron oxide nanoparticles. The reasons for the decrease in conductivity are: 11
ACCEPTED MANUSCRIPT
1- The remaining holes from the acid treatment that are not filled with iron oxide particles. 2- Filling the holes with undesirable materials. 3- Creating a barrier against electron motion because of the existence of two
CR IP T
kinds of conducting particles in the network. 4- A lesser conductivity of iron oxide than pure iron.
By using relation (2), the samples’ resistivity can be found at different voltages: RA , l
(2)
AN US
where l stands for the length of sample in the tube, R is the resistance and A is the cross section of the sample in the tube. Table 3 tabulates the samples’ resistivity at
AC
CE
PT
ED
M
different voltages.
Fig. 6. I-V diagram of the pristine, functionalized and Fe3O4/nanotubes.
12
ACCEPTED MANUSCRIPT
Table 3 Samples’ resistivity at different voltages.
79578 53052 2210 1895 1730 1705 1658 1554 1290 1266
99472 79578 14210 1730 1809 1895 2151 2287 2341 2422
132629 26526 9947 7958 5305 4263 4681 4521 4046 3923
CR IP T
Resistivity of MWCNT/ Fe3O4 nanocomposites (Ωm)
M
Voltage (v) 0.1 0.2 0.5 1 2 3 4 5 6 7
Resistivity of functionalized MWCNTs (Ωm)
AN US
Sample
Resistivity of pristine MWCNTs (Ωm)
3.5. Vibrating sample magnetometer (VSM)
ED
The room temperature magnetization curves of pristine MWCNTs, f-MWCNTs, and MWCNT/Fe3O4 nanocomposites are plotted in Fig. 7 to Fig. 9. The magnetic parameters
AC
CE
PT
are also tabulated in Table 4.
13
AN US
CR IP T
ACCEPTED MANUSCRIPT
AC
CE
PT
ED
M
Fig. 7. Magnetization curve of pristine MWCNTs.
Fig. 8. Magnetization curve of f-MWCNTs. 14
AN US
CR IP T
ACCEPTED MANUSCRIPT
M
Fig. 9. Magnetization curve of MWCNT/Fe3O4 nanocomposites.
Table 4
Ms (emu/g) 0.15 0.19 1.50
Mr (emu/g) 0 0 0
Hc (Oe) 10 10 0
property Ferromagnetic Ferromagnetic Superparamagnetic
CE
PT
Sample MWCNT f-MWCNT MWCNT/Fe3O4
ED
Magnetic parameters of pristine MWCNTs, f-MWCNTs, and MWCNT/Fe3O4 nanocomposites.
The results show that pristine carbon nanotubes have a Hc of about 10 (Oe) and
AC
Mr is close to zero, and they have an acceptable magnitude for the saturation magnetization Ms. So, it is worth mentioning that the presence of residual metals like Ni nanoparticles used in the CVD method are responsible for showing a ferromagnetic behavior in the MWCNTs’ loop hysteresis [25]. Functionalized nanotubes show ferromagnetic behavior according to the previous description, but compared with pristine MWCNTs, since the magnitude of their saturation 15
ACCEPTED MANUSCRIPT
magnetization has increased, they benefit from higher magnetic properties. This may originate from eliminating the impurities due to the acid treatment. A modification of the magnetic indices of magnetite coated MWCNTs is observed due to increasing the saturation magnetization and the vanishing amounts of Hc
CR IP T
and Mr.
3.6. Thermal Conductivity
The THW (Transient Hot Wire) method is a suitable route to measure the thermal conductivity of the powder samples. A schematic plan of the THW has been shown
AN US
in Fig. 10. Thermal conductivity (K) is an inherent property of materials, which is related to their ability in heat transfer. Determining the thermal conductivity is possible by using the THW method [26]. THW is a transient dynamic technique based on measuring the thermal increase at a distinctive distance from a linear heat
M
source (hot wire) set in tentative materials. If the heat source in the length of the tentative sample has a constant and uniform output, it is possible to calculate the
ED
thermal changes in a distinct time interval [27]. One ideal mathematical model is based on the conception of the hot wire as an ideal, extremely thin and long source
PT
which is surrounded by homogeneous and isotropic materials with a constant initial temperature. If q is the constant quantity of the heat generation in unit time and the
CE
heated wire unit at initial time t=0, in terms of (W.m-1), radial thermal flow will
AC
occur around the wire. The temperature increase ∆T (r, t) at the radial position r from the thermal source is: (
)
(3) (4) ( )
(5) 16
ACCEPTED MANUSCRIPT
where k is the thermal conductivity (W.m-1), A is the thermal diffusivity (m2.S-1)2, ρ is the density (kg.m-3), cP is the thermal capacity and γ is the Euler’s constant
AN US
CR IP T
(γ=0.5772157).
M
Fig. 10. Schematic plan of THW.
The temperature increase ∆T (r, t) is used as a time function to determine the thermal
ED
conductivity, k, using the calculation of the gradient K of the linear part of ∆T (r, t) versus the natural logarithm of time evolution (Ln (t)). (6)
PT
.
CE
The thermal data which was obtained in this work is collected in Table 5.
AC
Table 5
Data reported for te thermal conductivity of the samples.
Sample
pure water water+tritonX -100
Type of Sensor
Thermal Conducti vity (W/mK)
Tempe rature o C
KS-1
0.609
KS-1
0.604
r^2
Time of measurement (s)
(k_nfk)/kf
25
1
60
-----
25
1
60
-----
17
ACCEPTED MANUSCRIPT
Pristine MWCNT O-MW CNT Coated MWCNT
KS-1
0.616
25
1
60
1.99%
KS-1
0.615
25
1
60
1.82%
KS-1
0.618
25
1
60
2.32%
CR IP T
In this assessment, first, the thermal conductivity coefficient of water was measured at 25 oC, and the thermal conductivity coefficient of water+Trition X-100 was measured (0.5 mL of Triton is added to 25mL of water). In all of the experiments, 0.10 g of sample was added to 25 mL of water and 0.5 mL of Triton
AN US
X-100. The name of the device was KD-2 Pro which uses the Transient Hot Wire method to measure the thermal conductivity. The second column in Table 5 shows the type of sensor used in the device with the length of 6 cm and diameter of 3.1 mm. The seventh column also shows the magnitude of the thermal conductivity increase in terms of the basic fluid, which in this experiment is water as well as
M
Triton X-100. Fig. 11 reports on the thermal characterization results of the
AC
CE
PT
ED
investigated samples.
18
ACCEPTED MANUSCRIPT
Fig. 11. Comparison of thermal conductivity among pristine, functionalized and MWCNT/Fe3O4 nanocomposites.
As indicated in Fig. 11, it can be seen that the thermal conductivity has decreased from the functionalized to the pristine nanotubes. This is owing to the fact that nanotubes become far from together in suspension samples. So, during
CR IP T
moving from one nanotube to another nanotube, there is a resistance in the phonon’s trajectory. Therefore, a decrease in the thermal conductivity is expected. About the coated nanotubes with iron oxide nanoparticles, an increase in the thermal conductivity is significant. This result verifies the modification of the
AN US
thermal conductivity due to coating the carbon nanotubes. Because metals have a high thermal conductivity and lie on the created holes, then they cover the top of the holes which are phonon scattering centers and decrease the thermal resistivity
M
of nanotubes.
4. Conclusions
ED
In the present study, the synthesis of MWCNT-Fe3O4 was done successfully. FTIR spectroscopy showed the presence of the expected bonds related to
PT
MWCNTs, magnetite and also the functionalized groups of carbonyl and hydroxyl. The XRD patterns were in agreement with the prediction of coating MWCNTs with
CE
magnetite nanoparticles. TEM graphs verified the anticipated structure. In this experiment, lower values of resistivity and a higher degree of thermal conductivity
AC
were obtained in the manufactured nanocomposites. In addition, superparamagnetic behavior was observed in the MWCNT/Fe3O4 nanocomposites. References [1] [2]
S. Iijima, "Helical microtubules of graphitic carbon," nature, vol. 354, no. 6348, p. 56, 1991. J.-C. Charlier et al., "Enhanced electron field emission in B-doped carbon nanotubes," Nano Letters, vol. 2, no. 11, pp. 1191-1195, 2002.
19
ACCEPTED MANUSCRIPT
[9]
[10] [11]
[12] [13]
[14]
[15]
[16]
AC
[17]
CR IP T
[8]
AN US
[7]
M
[6]
ED
[5]
PT
[4]
F. Kong et al., "Continuous Ni-layer on multiwall carbon nanotubes by an electroless plating method," Surface and Coatings Technology, vol. 155, no. 1, pp. 33-36, 2002. L. Ang, T. A. Hor, G. Xu, C. Tung, S. Zhao, and J. L. Wang, "Decoration of activated carbon nanotubes with copper and nickel," Carbon, vol. 38, no. 3, pp. 363-372, 2000. Y. Zhang, Q. Zhang, Y. Li, N. Wang, and J. Zhu, "Coating of carbon nanotubes with tungsten by physical vapor deposition," Solid state communications, vol. 115, no. 1, pp. 51-55, 2000. J. Lee et al., "Al 2 O 3 nanotubes and nanorods fabricated by coating and filling of carbon nanotubes with atomic-layer deposition," Journal of crystal growth, vol. 254, no. 3, pp. 443-448, 2003. Z.-J. Liu, Z. Xu, Z.-Y. Yuan, W. Chen, W. Zhou, and L.-M. Peng, "A simple method for coating carbon nanotubes with Co–B amorphous alloy," Materials Letters, vol. 57, no. 7, pp. 1339-1344, 2003. X.-W. Wei, X.-J. Song, J. Xu, Y.-H. Ni, and P. Zhang, "Coating multi-walled carbon nanotubes with metal sulfides," Materials chemistry and physics, vol. 92, no. 1, pp. 159-163, 2005. C. Pham-Huu, N. Keller, L. Charbonniere, R. Ziessel, and M. Ledoux, "Carbon nanofiber supported palladium catalyst for liquid-phase reactions. An active and selective catalyst for hydrogenation of C [double bond, length half m-dash] C bonds," Chemical Communications, no. 19, pp. 18711872, 2000. D. J. Smith, R. Fisher, and L. Freeman, "High-resolution electron microscopy of metal-intercalated “Graphimets”," Journal of Catalysis, vol. 72, no. 1, pp. 51-65, 1981. D. Gozzi et al., "Synthesis and magnetic characterization of Ni nanoparticles and Ni nanoparticles in multiwalled carbon nanotubes," Journal of alloys and compounds, vol. 419, no. 1, pp. 32-39, 2006. R. Kozhuharova et al., "Well-aligned Co-filled carbon nanotubes: preparation and magnetic properties," Applied Surface Science, vol. 238, no. 1, pp. 355-359, 2004. H. Zhang, N. Du, P. Wu, B. Chen, and D. Yang, "Functionalization of carbon nanotubes with magnetic nanoparticles: general nonaqueous synthesis and magnetic properties," Nanotechnology, vol. 19, no. 31, p. 315604, 2008. Y. Li, T. Kaneko, T. Ogawa, M. Takahashi, and R. Hatakeyama, "Magnetic characterization of Fenanoparticles encapsulated single-walled carbonnanotubes," Chemical communications, no. 3, pp. 254-256, 2007. J. Wan, W. Cai, J. Feng, X. Meng, and E. Liu, "In situ decoration of carbon nanotubes with nearly monodisperse magnetite nanoparticles in liquid polyols," Journal of Materials Chemistry, vol. 17, no. 12, pp. 1188-1192, 2007. I. Brigger, C. Dubernet, and P. Couvreur, "Nanoparticles in cancer therapy and diagnosis," Advanced drug delivery reviews, vol. 54, no. 5, pp. 631-651, 2002. J. Ge, Y. Hu, M. Biasini, W. P. Beyermann, and Y. Yin, "Superparamagnetic magnetite colloidal nanocrystal clusters," Angewandte Chemie International Edition, vol. 46, no. 23, pp. 4342-4345, 2007. L. Kong, X. Lu, and W. Zhang, "Facile synthesis of multifunctional multiwalled carbon nanotubes/Fe 3 O 4 nanoparticles/polyaniline composite nanotubes," Journal of Solid State Chemistry, vol. 181, no. 3, pp. 628-636, 2008. X. Wang, Z. Zhao, J. Qu, Z. Wang, and J. Qiu, "Fabrication and characterization of magnetic Fe 3 O 4–CNT composites," Journal of Physics and Chemistry of Solids, vol. 71, no. 4, pp. 673-676, 2010. R. M. Cornell and U. Schwertmann, The iron oxides: structure, properties, reactions, occurrences and uses. John Wiley & Sons, 2003. K. Jiang et al., "Selective attachment of gold nanoparticles to nitrogen-doped carbon nanotubes," Nano Letters, vol. 3, no. 3, pp. 275-277, 2003.
CE
[3]
[18]
[19] [20] [21]
20
ACCEPTED MANUSCRIPT
[23]
[24]
[25]
[26]
AC
CE
PT
ED
M
AN US
[27]
Q. Zhang, M. Zhu, Q. Zhang, Y. Li, and H. Wang, "The formation of magnetite nanoparticles on the sidewalls of multi-walled carbon nanotubes," Composites Science and Technology, vol. 69, no. 5, pp. 633-638, 2009. S. Khosravani, S. B. Dehaghi, M. B. Askari, and M. Khodadadi, "The effect of various oxidation temperatures on structure of Ag-TiO 2 thin film," Microelectronic Engineering, vol. 163, pp. 6777, 2016. D. Caruntu, G. Caruntu, and C. J. O'Connor, "Magnetic properties of variable-sized Fe3O4 nanoparticles synthesized from non-aqueous homogeneous solutions of polyols," Journal of Physics D: Applied Physics, vol. 40, no. 19, p. 5801, 2007. G. R. Gordani and A. Ghasemi, "Optimization of carbon nanotube volume percentage for enhancement of high frequency magnetic properties of SrFe 8 MgCoTi 2 O 19/MWCNTs," Journal of Magnetism and Magnetic Materials, vol. 363, pp. 49-54, 2014. S. A. Kumar, K. S. Meenakshi, B. Narashimhan, S. Srikanth, and G. Arthanareeswaran, "Synthesis and characterization of copper nanofluid by a novel one-step method," Materials Chemistry and Physics, vol. 113, no. 1, pp. 57-62, 2009. W. Davis, "Hot-wire method for the measurement of the thermal conductivity of refractory materials," Compendium of Thermophysical Property Measurement Methods., vol. 1, p. 231, 1984.
CR IP T
[22]
21
Preparation and study of the electrical, magnetic and thermal properties of Fe3 O4 coated carbon nanotubes Mohammad Hassan Ramezan zadeh , Majid Seifi , Hoda Hekmatara , Mohammad Bagher Askari PII: DOI: Reference:
S0577-9073(17)30520-8 10.1016/j.cjph.2017.06.011 CJPH 297
To appear in:
Chinese Journal of Physics
Received date: Revised date: Accepted date:
30 April 2017 19 June 2017 27 June 2017
Please cite this article as: Mohammad Hassan Ramezan zadeh , Majid Seifi , Hoda Hekmatara , Mohammad Bagher Askari , Preparation and study of the electrical, magnetic and thermal properties of Fe3 O4 coated carbon nanotubes, Chinese Journal of Physics (2017), doi: 10.1016/j.cjph.2017.06.011
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
ACCEPTED MANUSCRIPT
Highlights
AC
CE
PT
ED
M
AN US
CR IP T
MWCNTs were coated with Fe3O4 nanoparticles using a wet chemical method. The TEM micrograph represented the well-established microstructure Fe3O4/MWCNTs. Improvements in the electrical and thermal conductivity of MWCNTs were observed. The Fe3O4/MWCNTs nanocomposites showed a superparamagnetic behavior.
1
of
ACCEPTED MANUSCRIPT
Preparation and study of the electrical, magnetic and thermal properties of Fe3O4 coated carbon nanotubes Mohammad Hassan Ramezan zadeh a, Majid Seifi a , *, Hoda Hekmatara b, Mohammad Bagher Askari a , c ,* a
CR IP T
Department of Physics, Faculty of Science, University of Guilan, Rasht 41335, Iran Department of Physics, Vali-e-Asr University of Rafsanjan, Iran c Department of Physics, Payame Noor University, PO Box 19395-3697 Tehran, Iran b
AN US
Corresponding author: Majid Seifi & Mohammad Bagher Askari Department of Physics, Faculty of Science, University of Guilan, Rasht 41335, Iran m_seifi2000@ yahoo.com (Majid Seifi) [email protected] (Mohammad Bagher Askari)
M
Abstract
ED
In this work, functionalized multiwalled carbon nanotubes (f-MWCNTs) were coated with Fe3O4 nanoparticles using a straightforward wet chemical method. The obtained magnetic nanocomposites were characterized by using Fourier transform
PT
infrared (FTIR) and X-ray diffraction (XRD) spectroscopies to investigate the
CE
chemical bonds and structures. Transmission electron microscopy (TEM) revealed the microstructure of the iron oxide coated MWCNTs. The electrical resistivity of
AC
pristine, functionalized, and MWCNT/Fe3O4 nanocomposites were measured by the two-probe method. The results showed that the electrical resistivity of the carbon nanotubes was decreased by the chemical functionalization and decoration with Fe3O4 nanoparticles. It was also observed that with increasing the applied voltage the resistivity of all the samples increased. Magnetic characterization showed a superparamagnetic behavior for the synthesized MWCNT/Fe3O4 nanocomposites. 2
ACCEPTED MANUSCRIPT
Thermal conductivity measurements of the samples in water showed that the functionalization of nanotubes decreased the thermal conductivity of water, but decorating the carbon nanotubes by magnetic nanoparticles increased the thermal conductivity of water.
CR IP T
Keywords: Carbon nanotubes; Fe3O4 nanoparticles; thermal properties; electrical properties; magnetic properties.
1. Introduction
AN US
Carbon nanotubes are important materials because of their electronic, magnetic and gas adsorption properties [1]. In order to make devices based on nanotubes with better properties and efficiencies, different ways have been offered and attempted [2]. Up to the present, some routes have been reported for coating carbon
M
nanotubes, such as electroless plating methods [3, 4], physical vapor deposition [5], atomic-layer deposition [6], and so on [7, 8]. Moreover, carbon nanotubes have
ED
extensive applications in catalysts, sensors, semiconductor devices and new booster materials. In addition, iron oxide nanoparticles are significant materials as effective
PT
catalysts. It is expected that the exposure of iron oxide nanoparticles on the surface of some one-dimensional materials, such as carbon nanotubes, will cause a more
CE
intense modification of the magnetic and catalytic properties of the onedimensional structure, because of the interaction between the iron oxide and the
AC
CNTs [9, 10]. Up to the present, different types of MWCNTs have been coated by Ni [11], Co [12], CoO [13], Fe [14], etc., but, iron oxide nanoparticles (such as maghemite and magnetite) have been under special investigation because of their low
toxicity,
stability,
and
biocompatibility
properties
in
physiological
environments [15-17]. In order to combine the benefits of MWCNTs and iron oxide nanoparticles, different routes have been used. 3
ACCEPTED MANUSCRIPT
2. Experiment 2.1. Materials MWCNTs with diameters and lengths ranging between 20-40 nm and 5-15 μm, respectively, and a minimum purity of 95% were purchased from Shenzhen
CR IP T
Nanotech Port Co. Ltd. Other raw materials including FeCl2.4H2O (Purity: 99.99%), FeCl3.6H2O (Purity: 98%), H2SO4 (95-98%), HNO3 (≥65%), and NaOH (≥97%) were purchased from Sigma Aldrich, Inc. 2.2. Functionalization of nanotubes
AN US
To functionalize the carbon nanotubes, 2 g of pristine MWCNTs were dispersed in 32 mL of the solution of H2SO4 and HNO3 (3/1) into a reaction flask. They were refluxed at 60 oC for 3 h. The mixture was cooled and diluted by distilled water. After that the mixture was dehydrated using a filter paper so that the remaining
M
water was removed, and then distilled water was added to it again. This work was constantly continued until the pH of the sample approached neutral magnitude.
ED
Finally, the sample was dried at 60 oC overnight until the sample became like black powder.
PT
2.3. Synthesis of MWCNT/Fe3O4 nanohybrid materials
CE
First 0.02 g of functionalized MWCNTs, 0.024 g of FeCl3.6H2O and 0.009 g of FeCl2.4H2O were put in a 100 mL balloon. Then 20 mL of nitric acid was added to
AC
this [18]. Next, the balloon was put under the frequency of 59 kHz in an ultrasonic device for 30 minutes. In the following step, in order to do reflux, the balloon was put into an oil bath at 120 oC for 4.5 h. Then the balloon was brought out from the container of oil. After the sample cooled, NaOH was added dropwise to it until neutral pH was achieved. In this stage, the mixture was poured over a micro membrane and deionized water was poured over the material several times. Then,
4
ACCEPTED MANUSCRIPT
the mixture was centrifuged several times in deionized water. After that the sample was dried at 100 oC for 2 h and then calcinated at 200 oC for 2 hours. 2.4. Characterizations Phase identification was carried out using a Holland Philips Xpert X-ray powder BRUKER®TENSOR27 in the range of 400-4000 cm-1.
CR IP T
diffraction (XRD) diffractometer with CuKα radiation (λ=0.15406 nm), and a
A JEOL JEM-2010 transmission electron microscope (TEM) at an accelerating voltage of 200 kV was used to determine and confirm the presence of nanoparticles
AN US
on the nanotube’s surfaces and the diameter of the nanotubes.
Electrical measurements of the sample were done by the two-probe method. The circuit included just a loop having a constant 10 kΩ resistor and the sample as the second one.
M
Magnetic properties of the nanocomposites were characterized by a vibrating sample magnetometer (VSM, Lakeshore7407) at room temperature.
ED
Thermal conductivity including the velocity field measurements were done by a three dimensional traversing hot-wire system installed by the Fara Sanjesh Saba
PT
(FSS) Company.
CE
3. Results and discussion
AC
3.1. Fourier transform infrared (FTIR) spectroscopy The structural and lattice constants of magnetite (Fe3O4) and maghemite (γ-
Fe2O3) are similar (0.8350 nm for maghemite and 0.8396 for magnetite), and both of them have a spinel-type structure. Hence, the identification of maghemite and magnetite from the XRD pattern is not readily possible [19]. A direct evidence is required to identify the crystal structure. Fig. 1 shows the FTIR spectra of pristine 5
ACCEPTED MANUSCRIPT
MWCNTs and MWCNT/ Fe3O4 nanocomposites. In comparison with the pristine MWCNTs’ spectrum in Fig. 1a, there is a peak at 570 cm-1 in Fig. 1b that can be ascribed to the existence of the stretching bonds of the Fe-O in tetrahedral and octahedral structures that is related to magnetite. In the case of maghemite the status is different, and there is a peak at 630 cm-1 [20]. The signals of 1630 cm-1 and
CR IP T
3430 cm-1 are related to the functionalized groups of carbonyl (1626 cm-1) and
CE
PT
ED
M
AN US
hydroxyl (3424 cm-1) attached to MWCNT, respectively [21].
AC
Fig. 1. FTIR spectra of (a) pristine MWCNTs, (b) MWCNTs coated with magnetite nanoparticles.
3.2. XRD pattern of the sample and its interpretation Fig. 2 shows a peak around 2θ=26o, which is a characteristic peak of graphite and is related to pristine MWCNTs. As shown in Fig. 3, regarding the diffraction 6
ACCEPTED MANUSCRIPT
patterns [19, 22], a strong peak around 2θ=26o is related to the reflection of (0 0 2) for graphite, and other peaks are related to magnetite with the reflections of a standard FCC (1 1 1), (2 2 0), (3 1 1), (4 0 0), (4 2 2), (5 1 1) and (4 4 0). In the following, Table 1 is related to the magnitudes of FWHM (full width at half
CR IP T
maximum) and height attributed to the important peaks of coated carbon nanotubes with iron oxide nanoparticles. It contains also the crystallite size of the iron oxide nanoparticles at important peaks calculated by the Scherrer equation [23]: ,
(1)
AC
CE
PT
ED
M
AN US
In relation (1), D represents the crystallite size, θ is the Bragg angle and β shows the amount of FWHM (full width at half maximum). Also, λ is used to represent the wavelength of copper radiation (1.54 Å). The average magnetite grain size ( ̅ ) is around 6 nm.
Fig. 2. XRD pattern of f-MWCNTs.
7
AN US
CR IP T
ACCEPTED MANUSCRIPT
M
Fig. 3. XRD pattern of MWCNT/Fe3O4 nanocomposites.
Table 1
ED
The estimated grain sizes of magnetite nanoparticles in MWCNT/Fe3O4 nanocomposites. Height
FWHM
D
̅
(counts)
(radian)
(nm)
(nm)
(2 2 0)
47
0.2362
6
6
(3 1 1)
136
0.4723
3
(4 0 0)
75
0.3936
4
(4 2 2)
65
0.2362
7
58
(5 1 1)
93
0.1940
8
63
(4 4 0)
113
0.2362
7
2θ (degree) 30
46
AC
54
CE
38
PT
hkl
3.3. Transmission electron microscopy (TEM) Fig. 4 is related to the TEM micrograph of carbon nanotubes coated with magnetite. It shows long nanotubes with diameters between 20 and 40 nm, which is 8
ACCEPTED MANUSCRIPT
a validation for the factory’s information about the purchased products. In addition, black spots in the intervals of 3 to 15 nm are magnetite nanoparticles that are attached to the outer surfaces of the nanotube’s body. This range of grain size is smaller than the superparamagnetic critical size of magnetite nanoparticles, which
PT
ED
M
AN US
CR IP T
is almost 20 nm [24].
CE
Fig. 4. TEM micrograph of carbon nanotubes coated with iron oxide nanoparticles.
AC
3.4. Measurement of electrical conductivity
In order to measure the electrical conductivity of materials, different ways have
been proposed. Because the sample is a powder, the two-wire method was used. In this method, the powders were compressed and put between two wires in a circuit using a capillary tube. By creating an appropriate electrical circuit, the DC conductivity of pristine, the functionalized and coated MWCNTs were analyzed. In 9
ACCEPTED MANUSCRIPT
order to determine the electrical resistance of the powder samples, they were put into incombustible insulators that were cylindrical with a radius of 2 mm and length of 5 mm. From the two sides of the tube, suitable metallic wires were in full contact with the samples. The voltage of the power supply was increased. This
CR IP T
way, the voltage of the two heads of the sample and also the current passing into the circuit can be noted. Fig. 5 shows the schematic plan of the sample as a DC circuit. In order not to have a short contact in the circuit, another resistance was successively put in the circuit. Table 2 shows the magnitudes of the electrical
AC
CE
PT
ED
M
AN US
current at different voltages of the two heads of the samples.
Fig. 5. Schematic plan of exposure of the powder samples in a DC circuit.
10
ACCEPTED MANUSCRIPT
Table 2 Magnitudes of the electric current at different voltages of the two heads of the samples.
The electrical current (functionalized MWCNTs) (A)
0 0.1 0.2 0.5 1 2 3 4 5 6 7
0 0.0005 0.0015 0.09 0.21 0.46 0.7 0.96 1.28 1.85 2.2
0 0.0004 0.001 0.014 0.23 0.44 0.63 0.74 0.87 1.02 1.15
The electrical current (Fe3O4 coated MWCNTs) (A)
CR IP T
Electrical Current (pristine MWCNTs) (A)
0 0.0003 0.003 0.02 0.05 0.15 0.28 0.34 0.44 0.59 0.71
ED
M
AN US
The voltage of two ends of sample (v)
Fig. 6 shows the I-V diagram of the pristine, functionalized and coated nanotubes.
PT
At low voltages, the behavior of the samples is linear (ohmic). At higher voltages, nonlinear (non-ohmic) behavior is seen, because of the increasing temperature and
CE
creating a tunneling current. The electric resistance of the functionalized nanotubes is larger than that of the pristine one, which is because of the creation of pentagon
AC
and heptagon holes on the nanotubes during the acid treatment. These holes cause scattering of the electrons and a decrease in the electric current. The largest magnitude of electric resistance is related to the coated nanotubes with iron oxide nanoparticles. The reasons for the decrease in conductivity are: 11
ACCEPTED MANUSCRIPT
1- The remaining holes from the acid treatment that are not filled with iron oxide particles. 2- Filling the holes with undesirable materials. 3- Creating a barrier against electron motion because of the existence of two
CR IP T
kinds of conducting particles in the network. 4- A lesser conductivity of iron oxide than pure iron.
By using relation (2), the samples’ resistivity can be found at different voltages: RA , l
(2)
AN US
where l stands for the length of sample in the tube, R is the resistance and A is the cross section of the sample in the tube. Table 3 tabulates the samples’ resistivity at
AC
CE
PT
ED
M
different voltages.
Fig. 6. I-V diagram of the pristine, functionalized and Fe3O4/nanotubes.
12
ACCEPTED MANUSCRIPT
Table 3 Samples’ resistivity at different voltages.
79578 53052 2210 1895 1730 1705 1658 1554 1290 1266
99472 79578 14210 1730 1809 1895 2151 2287 2341 2422
132629 26526 9947 7958 5305 4263 4681 4521 4046 3923
CR IP T
Resistivity of MWCNT/ Fe3O4 nanocomposites (Ωm)
M
Voltage (v) 0.1 0.2 0.5 1 2 3 4 5 6 7
Resistivity of functionalized MWCNTs (Ωm)
AN US
Sample
Resistivity of pristine MWCNTs (Ωm)
3.5. Vibrating sample magnetometer (VSM)
ED
The room temperature magnetization curves of pristine MWCNTs, f-MWCNTs, and MWCNT/Fe3O4 nanocomposites are plotted in Fig. 7 to Fig. 9. The magnetic parameters
AC
CE
PT
are also tabulated in Table 4.
13
AN US
CR IP T
ACCEPTED MANUSCRIPT
AC
CE
PT
ED
M
Fig. 7. Magnetization curve of pristine MWCNTs.
Fig. 8. Magnetization curve of f-MWCNTs. 14
AN US
CR IP T
ACCEPTED MANUSCRIPT
M
Fig. 9. Magnetization curve of MWCNT/Fe3O4 nanocomposites.
Table 4
Ms (emu/g) 0.15 0.19 1.50
Mr (emu/g) 0 0 0
Hc (Oe) 10 10 0
property Ferromagnetic Ferromagnetic Superparamagnetic
CE
PT
Sample MWCNT f-MWCNT MWCNT/Fe3O4
ED
Magnetic parameters of pristine MWCNTs, f-MWCNTs, and MWCNT/Fe3O4 nanocomposites.
The results show that pristine carbon nanotubes have a Hc of about 10 (Oe) and
AC
Mr is close to zero, and they have an acceptable magnitude for the saturation magnetization Ms. So, it is worth mentioning that the presence of residual metals like Ni nanoparticles used in the CVD method are responsible for showing a ferromagnetic behavior in the MWCNTs’ loop hysteresis [25]. Functionalized nanotubes show ferromagnetic behavior according to the previous description, but compared with pristine MWCNTs, since the magnitude of their saturation 15
ACCEPTED MANUSCRIPT
magnetization has increased, they benefit from higher magnetic properties. This may originate from eliminating the impurities due to the acid treatment. A modification of the magnetic indices of magnetite coated MWCNTs is observed due to increasing the saturation magnetization and the vanishing amounts of Hc
CR IP T
and Mr.
3.6. Thermal Conductivity
The THW (Transient Hot Wire) method is a suitable route to measure the thermal conductivity of the powder samples. A schematic plan of the THW has been shown
AN US
in Fig. 10. Thermal conductivity (K) is an inherent property of materials, which is related to their ability in heat transfer. Determining the thermal conductivity is possible by using the THW method [26]. THW is a transient dynamic technique based on measuring the thermal increase at a distinctive distance from a linear heat
M
source (hot wire) set in tentative materials. If the heat source in the length of the tentative sample has a constant and uniform output, it is possible to calculate the
ED
thermal changes in a distinct time interval [27]. One ideal mathematical model is based on the conception of the hot wire as an ideal, extremely thin and long source
PT
which is surrounded by homogeneous and isotropic materials with a constant initial temperature. If q is the constant quantity of the heat generation in unit time and the
CE
heated wire unit at initial time t=0, in terms of (W.m-1), radial thermal flow will
AC
occur around the wire. The temperature increase ∆T (r, t) at the radial position r from the thermal source is: (
)
(3) (4) ( )
(5) 16
ACCEPTED MANUSCRIPT
where k is the thermal conductivity (W.m-1), A is the thermal diffusivity (m2.S-1)2, ρ is the density (kg.m-3), cP is the thermal capacity and γ is the Euler’s constant
AN US
CR IP T
(γ=0.5772157).
M
Fig. 10. Schematic plan of THW.
The temperature increase ∆T (r, t) is used as a time function to determine the thermal
ED
conductivity, k, using the calculation of the gradient K of the linear part of ∆T (r, t) versus the natural logarithm of time evolution (Ln (t)). (6)
PT
.
CE
The thermal data which was obtained in this work is collected in Table 5.
AC
Table 5
Data reported for te thermal conductivity of the samples.
Sample
pure water water+tritonX -100
Type of Sensor
Thermal Conducti vity (W/mK)
Tempe rature o C
KS-1
0.609
KS-1
0.604
r^2
Time of measurement (s)
(k_nfk)/kf
25
1
60
-----
25
1
60
-----
17
ACCEPTED MANUSCRIPT
Pristine MWCNT O-MW CNT Coated MWCNT
KS-1
0.616
25
1
60
1.99%
KS-1
0.615
25
1
60
1.82%
KS-1
0.618
25
1
60
2.32%
CR IP T
In this assessment, first, the thermal conductivity coefficient of water was measured at 25 oC, and the thermal conductivity coefficient of water+Trition X-100 was measured (0.5 mL of Triton is added to 25mL of water). In all of the experiments, 0.10 g of sample was added to 25 mL of water and 0.5 mL of Triton
AN US
X-100. The name of the device was KD-2 Pro which uses the Transient Hot Wire method to measure the thermal conductivity. The second column in Table 5 shows the type of sensor used in the device with the length of 6 cm and diameter of 3.1 mm. The seventh column also shows the magnitude of the thermal conductivity increase in terms of the basic fluid, which in this experiment is water as well as
M
Triton X-100. Fig. 11 reports on the thermal characterization results of the
AC
CE
PT
ED
investigated samples.
18
ACCEPTED MANUSCRIPT
Fig. 11. Comparison of thermal conductivity among pristine, functionalized and MWCNT/Fe3O4 nanocomposites.
As indicated in Fig. 11, it can be seen that the thermal conductivity has decreased from the functionalized to the pristine nanotubes. This is owing to the fact that nanotubes become far from together in suspension samples. So, during
CR IP T
moving from one nanotube to another nanotube, there is a resistance in the phonon’s trajectory. Therefore, a decrease in the thermal conductivity is expected. About the coated nanotubes with iron oxide nanoparticles, an increase in the thermal conductivity is significant. This result verifies the modification of the
AN US
thermal conductivity due to coating the carbon nanotubes. Because metals have a high thermal conductivity and lie on the created holes, then they cover the top of the holes which are phonon scattering centers and decrease the thermal resistivity
M
of nanotubes.
4. Conclusions
ED
In the present study, the synthesis of MWCNT-Fe3O4 was done successfully. FTIR spectroscopy showed the presence of the expected bonds related to
PT
MWCNTs, magnetite and also the functionalized groups of carbonyl and hydroxyl. The XRD patterns were in agreement with the prediction of coating MWCNTs with
CE
magnetite nanoparticles. TEM graphs verified the anticipated structure. In this experiment, lower values of resistivity and a higher degree of thermal conductivity
AC
were obtained in the manufactured nanocomposites. In addition, superparamagnetic behavior was observed in the MWCNT/Fe3O4 nanocomposites. References [1] [2]
S. Iijima, "Helical microtubules of graphitic carbon," nature, vol. 354, no. 6348, p. 56, 1991. J.-C. Charlier et al., "Enhanced electron field emission in B-doped carbon nanotubes," Nano Letters, vol. 2, no. 11, pp. 1191-1195, 2002.
19
ACCEPTED MANUSCRIPT
[9]
[10] [11]
[12] [13]
[14]
[15]
[16]
AC
[17]
CR IP T
[8]
AN US
[7]
M
[6]
ED
[5]
PT
[4]
F. Kong et al., "Continuous Ni-layer on multiwall carbon nanotubes by an electroless plating method," Surface and Coatings Technology, vol. 155, no. 1, pp. 33-36, 2002. L. Ang, T. A. Hor, G. Xu, C. Tung, S. Zhao, and J. L. Wang, "Decoration of activated carbon nanotubes with copper and nickel," Carbon, vol. 38, no. 3, pp. 363-372, 2000. Y. Zhang, Q. Zhang, Y. Li, N. Wang, and J. Zhu, "Coating of carbon nanotubes with tungsten by physical vapor deposition," Solid state communications, vol. 115, no. 1, pp. 51-55, 2000. J. Lee et al., "Al 2 O 3 nanotubes and nanorods fabricated by coating and filling of carbon nanotubes with atomic-layer deposition," Journal of crystal growth, vol. 254, no. 3, pp. 443-448, 2003. Z.-J. Liu, Z. Xu, Z.-Y. Yuan, W. Chen, W. Zhou, and L.-M. Peng, "A simple method for coating carbon nanotubes with Co–B amorphous alloy," Materials Letters, vol. 57, no. 7, pp. 1339-1344, 2003. X.-W. Wei, X.-J. Song, J. Xu, Y.-H. Ni, and P. Zhang, "Coating multi-walled carbon nanotubes with metal sulfides," Materials chemistry and physics, vol. 92, no. 1, pp. 159-163, 2005. C. Pham-Huu, N. Keller, L. Charbonniere, R. Ziessel, and M. Ledoux, "Carbon nanofiber supported palladium catalyst for liquid-phase reactions. An active and selective catalyst for hydrogenation of C [double bond, length half m-dash] C bonds," Chemical Communications, no. 19, pp. 18711872, 2000. D. J. Smith, R. Fisher, and L. Freeman, "High-resolution electron microscopy of metal-intercalated “Graphimets”," Journal of Catalysis, vol. 72, no. 1, pp. 51-65, 1981. D. Gozzi et al., "Synthesis and magnetic characterization of Ni nanoparticles and Ni nanoparticles in multiwalled carbon nanotubes," Journal of alloys and compounds, vol. 419, no. 1, pp. 32-39, 2006. R. Kozhuharova et al., "Well-aligned Co-filled carbon nanotubes: preparation and magnetic properties," Applied Surface Science, vol. 238, no. 1, pp. 355-359, 2004. H. Zhang, N. Du, P. Wu, B. Chen, and D. Yang, "Functionalization of carbon nanotubes with magnetic nanoparticles: general nonaqueous synthesis and magnetic properties," Nanotechnology, vol. 19, no. 31, p. 315604, 2008. Y. Li, T. Kaneko, T. Ogawa, M. Takahashi, and R. Hatakeyama, "Magnetic characterization of Fenanoparticles encapsulated single-walled carbonnanotubes," Chemical communications, no. 3, pp. 254-256, 2007. J. Wan, W. Cai, J. Feng, X. Meng, and E. Liu, "In situ decoration of carbon nanotubes with nearly monodisperse magnetite nanoparticles in liquid polyols," Journal of Materials Chemistry, vol. 17, no. 12, pp. 1188-1192, 2007. I. Brigger, C. Dubernet, and P. Couvreur, "Nanoparticles in cancer therapy and diagnosis," Advanced drug delivery reviews, vol. 54, no. 5, pp. 631-651, 2002. J. Ge, Y. Hu, M. Biasini, W. P. Beyermann, and Y. Yin, "Superparamagnetic magnetite colloidal nanocrystal clusters," Angewandte Chemie International Edition, vol. 46, no. 23, pp. 4342-4345, 2007. L. Kong, X. Lu, and W. Zhang, "Facile synthesis of multifunctional multiwalled carbon nanotubes/Fe 3 O 4 nanoparticles/polyaniline composite nanotubes," Journal of Solid State Chemistry, vol. 181, no. 3, pp. 628-636, 2008. X. Wang, Z. Zhao, J. Qu, Z. Wang, and J. Qiu, "Fabrication and characterization of magnetic Fe 3 O 4–CNT composites," Journal of Physics and Chemistry of Solids, vol. 71, no. 4, pp. 673-676, 2010. R. M. Cornell and U. Schwertmann, The iron oxides: structure, properties, reactions, occurrences and uses. John Wiley & Sons, 2003. K. Jiang et al., "Selective attachment of gold nanoparticles to nitrogen-doped carbon nanotubes," Nano Letters, vol. 3, no. 3, pp. 275-277, 2003.
CE
[3]
[18]
[19] [20] [21]
20
ACCEPTED MANUSCRIPT
[23]
[24]
[25]
[26]
AC
CE
PT
ED
M
AN US
[27]
Q. Zhang, M. Zhu, Q. Zhang, Y. Li, and H. Wang, "The formation of magnetite nanoparticles on the sidewalls of multi-walled carbon nanotubes," Composites Science and Technology, vol. 69, no. 5, pp. 633-638, 2009. S. Khosravani, S. B. Dehaghi, M. B. Askari, and M. Khodadadi, "The effect of various oxidation temperatures on structure of Ag-TiO 2 thin film," Microelectronic Engineering, vol. 163, pp. 6777, 2016. D. Caruntu, G. Caruntu, and C. J. O'Connor, "Magnetic properties of variable-sized Fe3O4 nanoparticles synthesized from non-aqueous homogeneous solutions of polyols," Journal of Physics D: Applied Physics, vol. 40, no. 19, p. 5801, 2007. G. R. Gordani and A. Ghasemi, "Optimization of carbon nanotube volume percentage for enhancement of high frequency magnetic properties of SrFe 8 MgCoTi 2 O 19/MWCNTs," Journal of Magnetism and Magnetic Materials, vol. 363, pp. 49-54, 2014. S. A. Kumar, K. S. Meenakshi, B. Narashimhan, S. Srikanth, and G. Arthanareeswaran, "Synthesis and characterization of copper nanofluid by a novel one-step method," Materials Chemistry and Physics, vol. 113, no. 1, pp. 57-62, 2009. W. Davis, "Hot-wire method for the measurement of the thermal conductivity of refractory materials," Compendium of Thermophysical Property Measurement Methods., vol. 1, p. 231, 1984.
CR IP T
[22]
21