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

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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

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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

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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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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)

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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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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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5. CONCLUSION AND RECOMMENDATION 117

REFERENCES

APPENDICES

BIO DATA OF STUDENT

LIST OF PUBLICATIONS

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12`8

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