v
TABLE OF CONTENT
Abstract i
Abstrak ii
Dedication iii
Acknowledgement iv
Table of Content v
List of Tables viii
List of Figures ix
List of Abbreviations, Symbols and Nomenclatures xi
CHAPTER 1: INTRODUCTION
1.1 Background
1 1.2
Problem statement 3
1.3 Objectives 5
1.4 Scope
5
CHAPTER 2: LITERATURE REVIEW
2.1 Introduction
7 2.2
The nature of Carbon 7
2.3 Carbon nanotube
9 2.3.1
Single-walled carbon nanotube SWCNTs 10
2.3.2 Chirality of SWCNT
10 2.3.3
Multi-walled carbon nanotube MWCNTs 12
2.4 Doping system of CNT
13 2.4.1 Si atom doping system
14 2.5
CNTs based gas sensor 15
2.6 The nature of gas molecules
18 2.6.1 Carbon dioxide
18 2.6.2 Oxygen
19 2.6.3 Methanol
19
vi 2.7
Theoretical studies of nanotube on gas adsorption 19
2.8 Computational molecular modelling
21 2.8.1 First principles of quantum theory
21 2.8.2 Density functional theory
23 2.8.2.1
The Hohenberg-Kohn Theorems 24
2.8.2.2 Kohn-Sham Method
24 2.8.2.3
Exchange-Corellation Functional 25
2.8.3 Local density approximation 26
2.8.4 Generalized gradient approximation 26
2.8.5 K-Point Sampling 27
2.8.6 Materials studio software 28
2.8.6.1 CASTEP Cambridge serial total energy package 30
2.8.6.2 Dmol3 density functional calculation on
molecules 31
2.8 Summary of computational theory
32
CHAPTER 3: METHODOLOGY
3.1 Introduction
33 3.2
The computational materials studio software 34
3.3 Computer system specification
38 3.4
Building structure of single-wall carbon nanotube - STEP 1 39
3.5 Structure refinement – STEP 2
44 3.6
Calculation of material properties using quantum based software CASTEP and DMol3 – STEP 3
45
3.7 Analysis structure – STEP 4
48 3.7.1 Adsorption Energy
48 3.7.2 Electronic band structure
49 3.7.1.1
Band structure 49
3.6.1.2 High symmetry of Brillouin zone
50 3.7.3 Density of state
52
CHAPTER 4: RESULTS AND DISCUSSION
vii 4.1
Geometry properties 54
4.1.1 Pristine SWCNT and Si-doped SWCNT 56
4.1.2 O
2
on pristine SWCNT and Si-doped SWCNT 58
4.1.3 CO
2
on pristine SWCNT and Si-doped SWCNT 60
4.1.4 CH
3
OH on pristine SWCNT and Si-doped SWCNT 62
4.2 Adsorption energy analysis
65 4.3
Electronic properties 68
4.3.1 Pristine and Si doped SWCNT electronic properties analysis 68
4.3.2 O
2
adsorption 71
4.3.3 CO
2
adsorption 74
4.3.4 CH
3
OH adsorption 77
CHAPTER 5: CONCLUSIONS AND RECOMMENDATIONS
