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UNIVERSITI PUTRA MALAYSIA
EFFECTS OF TEMPERATURE, DEPOSITION TIME AND CATALYST
LOADING ON THE SYNTHESIS OF CARBON NANOTUBES IN A
VERTICAL CVD REACTOR
HENGAMEH HANAEI
ITMA 2011 19
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EFFECTS OF TEMPERATURE, DEPOSITION TIME AND CATALYST
LOADING ON THE SYNTHESIS OF CARBON NANOTUBES IN A
VERTICAL CVD REACTOR
BY
HENGAMEH HANAEI
Thesis Submitted to the School of Graduate Studies, University Putra Malaysia,
in Fulfillment of the Requirements for the Degree of Master of Science
June 2011
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DEDICATION
This thesis is dedicated to my parents, Amir Hanaei and Homa Kazemi.
Thank you for all your love, patience and sacrifice and thanks for all your supports.
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Abstract of thesis presented to the Senate University Putra Malaysia in fulfillment of
the requirements for the degree of Master of Science
EFFECTS OF TEMPERATURE, DEPOSITION TIME AND CATALYST
LOADING ON THE SYNTHESIS OF CARBON NANOTUBES IN A
VERTICAL CVD REACTOR
By
HENGAMEH HANAEI
June 2011
Chairman: Dr. Fakhru’L-Razi B Ahmadun, PhD
Faculty: Institute of Advanced Technology
Carbon nanotubes (CNTs), were discovered by Ijima in 1991. They have special
electrical, mechanical and electronic properties that make them attractive for a lot of
applications. However, there is no clear relation between synthesis parameters and
CNTs growth. Therefore more data investigations are required for Vertical CVD
synthesis of CNTs. This research intend to investigate the effects of some synthesis
parameters, namely, reaction temperature, catalyst loading, deposition time on
Vertical CVD growth of CNTs. In present study, CNTs were produced through
decomposition of acetone over a prepared catalyst Iron and Molybdenum supported
on Alumina (Fe-Mo/AL2O3). The effects of those parameters on Vertical CVD
synthesis of CNTs were studied using analysis of variance (ANOVA). After each run
the product, including deposited carbon and catalyst, was characterized using
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different analysis techniques. The morphology of as grown CNTs was observed by
Scanning Electron Microscope (SEM). Thermo Gravimetric Analysis (TGA) was
applied as this technique can reveal different forms of the carbon deposits (eg.
amorphous and CNTs) according to their different thermal stabilities. Besides that,
the effects of parameters on carbon deposit yield as well as their interactions were
statistically studied using ANOVA. Finally, the appropriate values for parameters
under study towards effective Vertical CVD synthesis of CNTs were determined full
factorial design of experiments method. This research demonstrated that by
increasing the reaction temperature to 950°C, more amorphous carbon was observed
due to deactivation of catalyst at high temperature. It was also observed that by
increasing the duration time, the yield of CNTs had decreased and by decreasing the
catalyst loading the yield and quality of CNTs had increased. It was proved that there
is a significant interaction between parameters under observation. In other words,
synthesis parameters are not independent variable. As a result of that the quality and
yield of the CNTs were appropriate achieved at 750°C reaction temperature, 40 min
deposition time and 5 gr catalysts loading.
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Abstrak tesis yang dikemukakan kapada Senat Universiti Putra Malaysia sebagi
memenuhikeperluan untuk Ijazah Master of Sains
KESAN SUHU, MASA PEMENDAPAN DAN PEMUATAN PEMANGKIN KE
ATAS SINTESIS NANOTIUB KARBON DI DALAM MENEGAK CVD
REAKTOR
Oleh
HENGAMEH HANAEI
June 2011
Pengerusi: Dr.Fakhru’L-Razi B Ahmadun, PhD
Fakulti: Institut Teknologi Bahan Termaju
Nanotiub karbon (CNTs), yang telah ditemui oleh Ijima pada 1991, mempunyai
keistimewaan sifat-sifat elektrik, mekanikal dan elektronik menjadikan ia menarik
untuk pelbagai kegunaan. Pemendapan wap kimia di dalam lapisan terbendalir
(Vertical CVD) muncul sebagai kaedah yang menjanjikan sintesis nanotiub karbon
dalam skala yang tinggi, kos yang rendah, dan hasil yang tinggi. Sebelum ini, tidak
ada hubungan yang jelas antara parameter-parameter sintesis (suhu tindak balas,
pemuatan pemangkin dan masa pemendapan) dengan pertumbuhan nanotiub karbon.
Maka, banyak penyiasatan diperlukan terhadap sintesis nanotiub karbon. Penyelidikan
ini menerangkan sintesis nanotiub karbon melalui penguraian aseton ke atas
pemangkin yang disediakan, iaitu Fe-Mo/AL2O3 melalui reaktor lapisan terbendalir.
Pada mulanya, sebelum aseton dimasukkan ke dalam reaktor, cecair aseton ditukar
menjadi wap oleh aliran gas argon yang telah dipanaskan terlebih dahulu
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menggunakan badan induk relau. Penyelidikan ini menumpukan kepada penyiasatan
kesan utama dan kesan interaksi parameter-parameter sintesis ke atas pertumbuhan
nanotiub karbon. Tambahan lagi, keadaan terbaik untuk sintesis nanotiub karbon telah
ditentukan. Bersamaan itu, kesan utama dan kesan interaksi telah disiasat berdasarkan
one-way dan two-way analysis of variance (ANOVA), Scanning Electron Microscope
(SEM) and Thermo Gravimetric Analysis (TGA) dalam eksperimen rawak, sementara
keadaan terbaik telah ditentukan berdasarkan kaedah rekabentuk eksperimen full
factorial, three-way ANOVA dan TGA. Penyelidikan ini menunjukkan bahawa dengan
meningkatkan suhu kepada 950°C, lebih banyak karbon amorfus telah diperhatikan
kerana ketiadaaan pemangkin pada suhu tinggi. Sementara itu, telah diperhatikan
bahawa dengan mengurangkan tempoh masa, hasil nanotiub karbon berkurang dan
dengan mengurangkan pemuatan pemangkin, hasil dan kualiti nanotiub karbon telah
meningkat. Penyiasatan ke atas kesan interaksi telah menunjukkan bahawa interaksi
darjah kedua dan ketiga antara parameter-parameter di atas mempunyai kesan penting
ke atas hasil karbon dan nanotiub karbon. Juga, hasil dari pelbagai keadaan sintesis
yang telah disiasat untuk menentukan keadaan terbaik nanotiub karbon, telah didapati
bahawa kualiti dan hadil nanotiub karbon adalah terbaik pada suhu tindakbalas pada
750°C, masa pemendapan selama 40 min dan pemuatan pemangkin sebanyak 5 gram.
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ACKNOWLEDGEMENTS
In the name of God
I would like to express my deepest gratitude and sincere thank to my main supervisor,
Professor Dr.Fakhru’L-Razi Ahmadun for the persistent guidance, assistance, support
and understanding throughout the study priod.
Gratitude and thanks are also extended to all members of the graduate committee,
Dr.Dayang Radiah Awang Biak and Dr.Intan Salwani Ahamad for their constructive
comments, advice and guidance.
Last but not least, the utmost gratitude goes to my beloved mother, father, brothers
and sisters for their wise advices, patience, understanding, sacrifices, and tolerance
during the course of my study.
I would also like to thank my friends, and especially my laboratory mate Firuzeh
Danafar for their support and help.
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This thesis was submitted to the senate of University Putra Malaysia and has
been accepted as fulfillment of the requirement for the degree of Master of
Science. The members of the supervisory committee are as follows:
Fakhru`L-Razi B Ahmadun, PHD
Professor
Faculty of Engineering
University Putra Malaysia
(Chairman)
Dayang Radiah Binti Awang Biak, PHD
Lecturer
Faculty of Engineering
University Putra Malaysia
(Member)
Intan Salwani Binti Ahamad, PHD
Lecturer
Faculty of Engineering
University Putra Malaysia
(Member)
Hasanah Mohd Ghazali, PhD Professor and Dean School of Graduate Studies
Universiti Putra Malaysia
Date:
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DECLARATION
I declare that the thesis is my original work except for quotations and citations which
have been duly acknowledged. I also declare that it has not been previously, and is
not concurrently, submitted for any other degree at Universiti Putra Malaysia or at
any other institution.
HENGAMEH HANAEI
Date: 23 June 2011
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TABLE OF CONTENTS
Page
ABSTRACT
ABSTRAK
ACKNOWLEDGEMENTS
APPROVAL
DECLARATION
TABLE OF CONTENTS
LIST OF TABLES
LIST OF FIGURES
LIST OF ABBREVIATIONS
iii
v
vii
viii
x
xi
xiv
xv
xviii
CHAPTER
1. INTRODUCTION
1.1 Background of Research
1.2 Problem Statement
1.3 Objectives of Research
1.4 Safety Carbon Nanotubes
1.5 Scope of the study
1.6 Research Framework
1
2
3
4
4
5
2. LITERATURE REVIEW
2.1 Introduction
2.2 Structure of carbon nanotubes
2.2.1 Carbon
2.2.2 Carbon Nanotubes (CNTs)
2.3 Properties of carbon nanotubes
2.3.1 Mechanical Properties of CNTs
2.3.2 Electrical Properties of CNTs
2.3.3 Thermal Properties of CNTs
2.3.4 Chemical Properties of CNTs
2.3.5 Electronic Properties of CNTs
2.4 Application of CNT
2.4.1 Electronic Devices
2.4.2 Sensors
2.4.3 Probes
2.4.4 Field Emission Devices
2.4.5 Composites
2.4.6 Energy Storage
2.5 Synthesis Method of Carbon Nanotubes
6
6
6
9
14
14
15
16
16
17
17
18
18
18
19
19
19
20
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2.5.1 Arc Discharge method
2.5.2 Laser Ablation method
2.5.3 Chemical Vapor Deposition(CVD) method
2.6 Development of CNTs Synthesis Method in CVD
Reactor
2.6.1 CNTs growth mechanism in Vertical CVD
2.7 Parameters Influencing CNTs growth in Vertical
CVD
2.7.1 Influencing of Temperature
2.7.2 Influencing of Deposition Time
2.7.3 Influencing of Carbon Source
2.7.4 Influencing of Metal Catalyst
2.7.5 Influencing of Carrier Gas
2.8 Summary
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22
24
24
27
28
30
30
31
32
33
33
3. METHODOLOGY
3.1 Introduction
3.2 Materials
3.3 Catalyst Preparation
3.4 Vertical CVD Setup
3.5 Carbon Nanotubes Synthesis
3.6 Sample Growth Procedure
3.7 Statistically Analysis
3.8 Characterization of CNT
3.8.1 Scanning Electron Microscopy (SEM)
3.8.2 Transmission Electron Microscopy (TEM)
3.8.3 Thermo gravimetric analysis (TGA)
3.8.4 Energy Dispersive X-ray Spectroscopy
(EDX)
35
35
36
37
39
41
46
46
47
48
50
52
4. RESULT AND DISCUSSION
4.1 Introduction
4.2 The Effect of Synthesis Parameters on CNTs
Growth
4.2.1 Deposition Time
4.2.2 Catalyst Loading
4.2.3 Reaction Temperature
4.3 Interaction Effect of Synthesis Parameters
4.3.1 Reaction Temperature_Deposition Time
4.3.2 Reaction Temperature_Catalyst Loading
4.3.3 Deposition Time_Catalyst Loading
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53
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69
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4.4 Determining the Appropriate Values of Parameters
for Synthesis of CNTs via VERTICAL CVD
Using Acetone as a Carbon Source on Fe-Mo/Al2O3
4.5 Summary
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116
5. CONCLUSION AND RECOMMENDATION 117
REFERENCES
APPENDICES
BIO DATA OF STUDENT
LIST OF PUBLICATIONS
121
12`8
131
132