vii
TABLE OF CONTENTS
CHAPTER
1
2
TITLE
PAGE
DECLARATION
ii
DEDICATION
iii
ACKNOWLEDGMENTS
iv
ABSTRACT
v
ABSTRAK
vi
TABLE OF CONTENT
vii
LIST OF TABLES
xii
LIST OF FIGURES
xiii
LIST OF ABBREVATIONS
xvi
LIST OF SYMBOLS
xviii
LIST OF APPENDICES
xix
INTRODUCTION
1
1.1
Background of Study
1
1.2
Statement of Problems
3
1.3
Objectives
6
1.4
Scope of Study
6
1.5
Significant of Study
7
LITERATURE REVIEW
8
2.1
Fuel Cell Overview
8
2.1.1 Type of Fuel Cells
9
2.1.2 Fuel Cell System
10
2.1.3 Direct Methanol Fuel Cell (DMFC)
13
2.2
Membrane Electrode Assembly
17
2.3
Membrane Material for Direct Methanol Fuel
19
viii
Cell (DMFC)
3
2.4
Sulfonated Poly ( ether ether ketone) (SPEEK)
21
2.5
Graphene Oxide
23
2.6
Reduced Graphene Oxide
25
2.7
Reducing Agents
27
EXPERIMENTAL
29
3.1
Introduction
29
3.2
Chemicals
31
3.3
Material Preparation
31
3.3.1 Preparation of Graphene Oxide
31
3.2.2 Preparation of reduced Graphene Oxide
32
Membrane Preparation
32
3.4.1
Sulfonation Reaction Process
32
3.4.2
Preparation of SPEEK/rGO Membrane
33
3.4
3.5
Instrumentation
33
3.5.1
Fourier Transform Infrared (FTIR)
34
3.5.2
X-ray Diffraction (XRD)
34
3.5.3
Transmission Electron Microscopy
(TEM)
3.5.4
3.6
Conductivity Measurement
35
35
Single Direct Methanol Fuel Cell Test
36
3.6.1
36
Preparation of Membrane Electrode
Assembly, MEA
3.6.2
Single Direct Methanol Fuel Cell
38
Performance
4
RESULTS AND DISCUSSION:
39
4.1
Introduction
39
4.2
Pretreatment Step
40
4.3
Characterizations of Reduced Graphene Oxide
40
4.3.1
41
Functional Group of Reduced Graphene
Oxide by Fourier Transform Infrared
ix
4.3.2
Structural Properties of Reduced
43
Graphene Oxide by X-Ray Diffraction
4.3.3 Morphological structure of Reduced
45
Graphene Oxide by Transmission
Electron Microscopy (TEM).
4.4
The Effect of Different Temperature on Physic-
46
Chemical Properties of Reduced Graphene
Oxide
4.4. 1 Functional Group of Reduced Graphene
46
Oxide at Different Temperature by
Fourier Transform Infrared (FTIR)
4.4.2
Structural Properties of Reduced
49
Graphene Oxide at Different
Temperature by X-Ray Diffraction
4.5
The Effect of Reaction Time on Physic-
52
Chemical Properties of Reduced Graphene
Oxide
4.5.1. Functional Groups of Reduced
52
Graphene Oxide at Different Reaction
Time by Fourier Transform Infrared
(FTIR)
4.5.2
Structural Properties of Reduced
54
Graphene Oxide at Different Reaction
Time by X-Ray Diffraction
4.6
The Effect of Reducing Agents on Physic-
55
Chemical Properties of Reduced Graphene
Oxide.
4.6.1
Functional Groups of Reduced Graphene
55
Oxide with Different Reductant by
Fourier Transform Infrared (FTIR)
4.6.2
Structural Properties of Reduced
Graphene Oxide with different
Reductant by X-Ray Diffraction
58
x
4.7
Conductivity Studies
60
4.7.1
60
Effect of Reaction Time on The
Conductivity of Reduced Graphene
Oxide
4.7.2 Effect of Reducing Agents on The
62
Conductivity of Reduced Graphene
Oxide
4.8
Characterization of SPEEK55 polymer
64
4.8.1 Functional Groups of SPEEK55
64
Membrane by Fourier Transform
Infrared (FTIR)
4.9
Direct Methanol Fuel Cell Performance Test
65
4.9.1 Effect of Air Flowrate on the
66
performance of SPEEK55/rGO MEA
4.9.2 Curent Density vs Open Circuit Voltage
69
Studies SPEEK55/rGO MEA
5
4.9.3 Power density of SPEEK55/rGO MEA
71
4.9.4 Stability studies of SPEEK55/rGO MEA
73
4.10
76
Overall Membranes Performance
CONCLUSIONS AND RECOMMENDATION
80
5.1
Conclusion
80
5.2
Recommendations
81
REFERENCES
83
APPENDIX
94
xi
LIST OF TABLES
TABLE NO.
TITLE
PAGE
2.1
Classification of fuel cells
10
2.2
Electrode reaction of different fuel cells type
12
4.1
FTIR wavenumber of each functional group of
42
graphene oxide and reduced graphene oxide
4.2
FTIR wavenumber of each functional group of
48
graphene oxide and reduced graphene oxide for 6
hours at different temperature.
4.3
FTIR wavenumber of each functional group of
48
graphene oxide and reduced graphene oxide for
18 hours at different temperature.
4.4
FTIR wavenumber of each functional group of
49
graphene oxide and reduced graphene oxide for
24 hours at different temperature.
4.5
FTIR wavenumber of each functional group of
53
graphene oxide and reduced graphene oxide at
different reaction time
4.6
FTIR wavenumber of each functional group of
57
graphene oxide and reduced graphene oxide with
different reducing agents
4.7
Electrical resistivity and electrical conductivity data
60
for graphene oxide and graphene.
4.8
Electrical conductivity data of graphene oxide and
reduced graphene by different reducing agents
62
xii
LIST OF FIGURES
FIGURE NO.
TITLE
PAGE
2.1
Basic system work in fuel cell
11
2.2
Schematic diagram of DMFC systems
14
2.3
Typical polarization curves of (a) voltage and (b)
16
power density
2.4
DMFC components
18
2.5
Chemical structure of Nafion
19
2.6
Chemical structure of polymer electrolyte membranes
20
based on hydrocarbon polymers
2.7
Sulfonation of PEEK
22
2.8
Graphene oxide layer structure
24
3.1
Flowchart of the process involved in the study
30
3.2
Preparation of MEA
37
3.3
DMFC test system
38
4.1
FTIR spectra of (a) graphite and (b) graphene oxide
40
and (c) reduced graphene oxide
4.2
XRD pattern of (a) graphite, (b) graphene oxide and
43
(c) reduced graphene oxide
4.3
TEM image of graphene oxide and reduced graphene
45
oxide
4.4
FTIR spectra of (a) graphite, (b) graphene oxide,
47
reduced graphene oxide at 6hours reaction time with
different temperature (c) room temperature, (d) 50o C
and (e) 80o C
4.5
XRD pattern of (a) graphene oxide, graphene at 6
hours stirring time with different temperature (b) room
50
xiii
temperature, (c) 50o C and (d )80o C
4.6
XRD pattern of (a) graphene oxide, graphene at 18
50
hours stirring time with different temperature (b) room
temperature, (c) 50o C and (d )80o C
4.7
XRD pattern of (a) graphene oxide, graphene at 24
51
hours stirring time with different temperature (b) room
temperature, (c) 50o C and (d )80o C
4.8
FTIR spectra of (a) graphite, (b) graphene oxide,
52
graphene with different reaction time; (c) 6 hours, (d)
18 hours, and (e) 24 hours at room temperature
4.9
XRD pattern of (a) graphite, (b) graphene oxide,
54
graphene with different reaction time; (c) 6 hours, (d)
18 hours, and (e) 24 hours at room temperature
4.10
FTIR spectra of (a) graphene oxide, (b) reduced
56
graphene by sodium borohydride, (c) reduced
graphene by formic acid and (d) reduced graphene by
oxalic acid.
4.11
XRD pattern of (a) graphene oxide, (b) reduced
59
graphene by sodium borohydride, (c) reduced
graphene by formic acid and (d) reduced graphene by
oxalic acid.
4.12
FTIR spectra of PEEK and SPEEK55
64
4.13
Graph of average open circuit voltage versus air
67
flowrate at 1M methanol
4.14
Graph of average open circuit voltage versus air
67
flowrate at 2M methanol
4.15
Polarization curve of cell voltage versus current
69
density at 1M methanol
4.16
Polarization curve of cell voltage versus current
70
density at 2M methanol
4.17
Polarization curve of power density versus current
density at 1M methanol
72
xiv
4.18
Polarization curve of power density versus current
72
density at 2M methanol
4.19
Voltage Stabilization curve of time versus voltage at
74
1M methanol
4.20
Voltage Stabilization curve of time versus voltage at
75
2M methanol
4.21
OCV of membranes at different methanol
76
concentration
4.22
Power density of membranes at different methanol
78
concentration
4.23
Initial voltage of membranes at different methanol
concentration
79
xv
LIST OF ABBREVATIONS
AFC
- Alkaline Fuel Cell
BSA
- Bovine Serum Albumin
C
- Carbon
CMG
- Chemically Modified Graphene
CNT
- Carbon Nanotube
CV
- Cyclic Voltammetric
CVD
- Chemical Vapour Deposition
DMFC
- Direct Methanol Fuel Cell
DS
- Degree of Sulfonation
FC
- Fuel Cell
FESEM
- Field Emission Scanning Electron Microscope
FET
- Field Effect Transistors
G
- Graphene
GNS
- Graphene Nano Sheet
GO
- Graphene Oxide
g/mol
- Gram per mol
1
H NMR
- Hydrogen-Nucleur Magnetic Resonance
MCFC
- Molten Carbonate Fuel Cell
MEA
- Membrane Electrode Assembly
NaBH4
- Sodium Borohydride
NaOH
- Sodium Hydroxide
NMP
- N-methylprrolidone
OCV
- Open Circuit Voltage
PAFC
- Phosphoric Acid Fuel Cell
PEM
- Polymer Electrolyte Membrane
PEMFC
- Proton Exchange Membrane Fuel Cell
PEEK
- Poly (ether ether ketone)
xvi
PFI
- Perfluorinated
SEM
- Scanning Electron Microscope
SOFC
- Solid Oxide Fuel Cell
SPEEK
- Sulfonated Poly (ether ether ketone)
SPEEK/G
- Graphene Sulfonated Poly (ether ether ketone)
TEM
- Transmission Electron Microscopy
TGA
- Thermal Gravimetric Analysis
XRD
- X-Ray Diffraction
xvii
LIST OF SYMBOLS
Å
- Angstroms
A
- Ampere
A/ cm2
- Area per square centimeter
g
- Gram
g/mol
- Gram per mol
i
- Current
L
- Liter
m
- Meter
mL
- Mililiter
nm
- Nanometer
ppm
- Part per million
W/ cm2
- Watts per square centimeter
V
- Voltage
R
- Resistance
θ
- Theta
λ
- Wavelength
ρ
- Resistivity
σ
- Conductivity
Ω
- Ohm
S
- Siemens