24
STUDY ON COPPER INCORPORATED MESOPOROUS SILICA SBA-15 FOR N 2 O CATALYTIC DECOMPOSITION MOHD HAIZAL MOHD HUSIN DOCTOR OF PHILOSOPHY (INDUSTRIAL CHEMISTRY) UNIVERSITI MALAYSIA PAHANG
STUDY ON COPPER INCORPORATED
MESOPOROUS SILICA SBA-15 FOR N2O
CATALYTIC DECOMPOSITION
MOHD HAIZAL MOHD HUSIN
DOCTOR OF PHILOSOPHY
(INDUSTRIAL CHEMISTRY)
UNIVERSITI MALAYSIA PAHANG
UNIVERSITI MALAYSIA PAHANG
DECLARATION OF THESIS AND COPYRIGHT
Author’s Full Name : MOHD HAIZAL MOHD HUSIN
Date of Birth : 10 APRIL 1976
Title : STUDY ON COPPER INCORPORATED MESOPOROUS
SILICA SBA-15 FOR N2O CATALYTIC DECOMPOSITION
Academic Session : Semester II 2015/2016
I declare that this thesis is classified as:
CONFIDENTIAL (Contains confidential information under the Official Secret Act 1997)*
RESTRICTED (Contains restricted information as specified by the organization where research was done)*
OPEN ACCESS I agree that my thesis to be published as online open access (Full Text)
I acknowledge that Universiti Malaysia Pahang reserve the right as follows:
1. The Thesis is the Property of Universiti Malaysia Pahang
2. The Library of Universiti Malaysia Pahang has the right to make copies for the
purpose of research only.
3. The Library has the right to make copies of the thesis for academic exchange.
Certified By:
(Student’s Signature) (Supervisor’s Signature)
760410055269 DR. CHIN SIM YEE
New IC/Passport Number Name of Supervisor
Date: 15 July 2016 Date: 15 July 2016
SUPERVISOR’S DECLARATION
I hereby declare that I have checked this thesis and in my opinion, this thesis is adequate
in terms of scope and quality for the award of the degree of Doctor of Philosophy in
Industrial Chemistry.
______________________
(Supervisor’s Signature)
Full Name : DR. CHIN SIM YEE
Position : ASSOCIATE PROFESSOR FACULTY OF CHEMICAL AND
NATURAL RESOURCES ENGINEERING
Date : 15 JULY 2016
STUDENT’S DECLARATION
I hereby declare that the work in this thesis is based on my original work except for
quotations and citation which have been duly acknowledged. I also declare that it has
not been previously or concurrently submitted for any other degree at Universiti
Malaysia Pahang or any other institutions.
______________________
(Author’s Signature)
Full Name : MOHD HAIZAL BIN MOHD HUSIN
ID Number : PKD10004
Date : 15 JULY 2016
STUDY ON COPPER INCORPORATED MESOPOROUS SILICA SBA-15 FOR N2O CATALYTIC DECOMPOSITION
MOHD HAIZAL MOHD HUSIN
Thesis submitted in fulfillment of requirements for the award of degree of
Doctor of Philosophy
Faculty of Chemical & Natural Resources Engineering UNIVERSITI MALAYSIA PAHANG
JULY 2016
ii
DEDICATION
I dedicate this dissertation to my family and many friends. My deep feeling of gratitude is to my loving parents, Haji Husin and Hajah Zainab, whose words of encouragement always motivate me to work harder. Al-fatihah to my late wife, Rozieyati, without whose caring supports it would not have been possible for me to complete this work during her life. To my loving children, Fathin, Hakim, Arief, and Hafiz thank you for your patience and understanding. I also dedicate this dissertation to all my many friends and members of the Faculty of Mechanical Engineering, Universiti Teknikal Malaysia Melaka who have encouraged me throughout the process. I will always appreciate all that they have done in helping me.
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ACKNOWLEDGEMENT
I thank all who have been generous with their expertise and valuable time in assisting me in this work. A special thanks to Prof. Mohd Ridzuan Nordin and Associate Professor Chin Sim Yee, my supervisors for their countless hours of reflecting, reading, encouraging, and for their patience throughout the entire process. Thank you too to Prof. Liew Kong Yong and Prof. Jinli Li from South-Central University for Nationality, Wuhan, People Republic of China for facilitating my research. I would also like to acknowledge and thank all technical staff of Faculty of Industrial Sciences & Technology, Universiti Malaysia Pahang for providing all assistances requested. Special thanks go to the members of staff from Institute of Postgraduate Studies UMP for their continued support in my prolonged candidature. Finally I would like to record my special appreciation to Universiti Teknikal Malaysia Melaka for the scholarship and study leave granted on me in relation to this work.
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ABSTRACT
Nitrous oxide (N2O) is an environmental pollutant because it is a relatively strong greenhouse effect gas and contributes towards the destruction of ozone in the stratosphere. Direct decomposition of N2O by catalysts represents one of the potential solutions to minimize N2O emissions. This research focuses on Cu incorporation into SBA-15 mesoporous silica by pH modification method using hexamethylenetetramine (HMTA) as an internal pH-modifier and its potential use as a catalyst for N2O decomposition. The effect of acidity on SBA-15 preparation through different initial HCl concentration and the addition of HMTA as pH modifier were investigated. The SBA-15 formed well-ordered hexagonal mesoporous structure at high acidity (2.0 M) and poor ordered hexagonal pore structure at low acidity condition (0.005 M). It was found that under moderate acidic condition (0.1 M HCl) with addition of HMTA (HMTA:Si molar ratio 1:10), well-ordered hexagonal mesoporous SBA-15 could be produced. Meanwhile, copper was chosen for further studies on metal incorporation of SBA-15 (M/SBA-15) because Cu-containing SBA-15 has the highest catalytic activity for N2O decomposition compared to that of other first row transition metals impregnated on SBA-15. Copper incorporated mesoporous silica (Cu-SBA-15) has been successfully prepared by direct synthesis under medium acidic condition with addition of HMTA as a pH modifier. The Cu/SBA-15 produced were characterised using XRD, N2 adsorption-desorption, TEM, SEM, FTIR, UV-vis, XPS and TPR. The results indicate that Cu was mainly incorporated into the framework of SBA-15. The unit-cell, surface area, pore volume and wall thickness increased after the incorporation of the copper ions in SBA-15. HMTA plays a very important role to increase internal pH in order to introduce copper into the framework of SBA-15 silica. Cu loading on Cu/SBA-15 determined using AAS is almost the same to the initial Cu amount, when the pH value is above isoelectronic of silica (pH=2) due to addition of HMTA. Higher amount of HMTA, however, lead to the destruction of SBA-15 structure. Compared with Cu/SBA-15 impregnation method, Cu/SBA-15 prepared through pH modification method shows much higher activity for N2O catalytic decomposition due to 80% N2O conversion at 550 C and reached 100% at 600 °C. The activation energy for the reaction catalysed by Cu/SBA-15 prepared through pH modification method is 91.9 – 121.6 kJ/mol. This is much lower compared to that catalysed by Cu/SBA-15 prepared though impregnation, that is in the range between 148.5 – 173.9 kJ/mol. Cu/SBA-15 incorporated sample also has higher activity due catalytic activity started at 300 °C and reaches more 80% conversion at 500 °C for catalytic reduction of N2O by CH4.
v
ABSTRAK
Nitrus oksida (N2O) adalah bahan pencemar alam sekitar kerana ia merupakan gas kesan rumah hijau yang agak kuat dan boleh menyebabkan kemusnahan ozon dalam stratosfera. Penguraian langsung N2O menggunakan kaedah pemangkin merupakan salah satu penyelesaian yang berpotensi meminimumkan pelepasan N2O. Kajian ini menumpu kepada penyediaan mangkin Cu yang digabungkan dengan SBA-15 silika berliang meso melalui sintesis langsung secara pengubahsuaian pH dengan menggunakan heksametiltetramin (HMTA) sebagai pengubah pH dalaman dan potensi penggunaan bahan ini sebagai mangkin bagi tindak balas penguraian N2O. Kajian kesan keasidan dalam penyediaan SBA-15 berdasarkan perbezaan kepekatan awalan larutan HCl dan penambahan HMTA sebagai pH diubahsuai telah dilakukan. Bahan SBA-15 yang terhasil menunjukkan struktur heksagon berliang meso yang teratur pada keasidan yang tinggi (2.0 M HCl) manakala struktur liang heksagon yang tidak teratur terbentuk pada keadaan keasidan yang rendah (0.005 M HCl). Hasil kajian menunjukkan keadaan berasid sederhana (0.1 M HCl) dengan penambahan HMTA (HMTA: Si nisbah molar 1:10) mampu menghasilkan struktur heksagon berliang meso yang teratur. Sementara itu, kuprum telah dipilih untuk kajian lanjutan terhadap logam digabungkan dengan SBA-15 (M/SBA-15). Ini kerana sampel SBA-15 yang mengandungi Cu (Cu-SBA-15) menunjukkan aktiviti paling aktif dalam tindak balas penguraian N2O berbanding sampel yang mengandungi logam peralihan baris pertama yang lain yang telah disediakan melalui kaedah pengisitepuan. Kuprum yang bergabung dengan silika berliang meso (Cu/SBA-15) telah dihasilkan menggunakan keadaan berasid sederhana berserta dengan penambahan HMTA sebagai agen pengubah pH. Sampel Cu/SBA-15 yang terhasil dicirikan menggunakan XRD, N2 penjerapan-penyahjerapan, TEM, SEM, FTIR, UV-vis, XPS dan TPR. Dapatan analisa menunjukkan bahawa atom Cu telah bergabung ke dalam kerangka silika SBA-15. Unit-sel, luas permukaan, isi padu liang dan ketebalan dinding meningkat selepas penggabungan ion kuprum dalam SBA-15. HMTA memainkan peranan yang amat penting untuk meningkatkan pH dalaman larutan supaya dapat memasukkan kuprum ke dalam rangka silika SBA-15. Muatan Cu yang diukur menggunakan AAS menunjukkan kuantiti Cu yang hampir sama dengan kuantiti awal, apabila nilai pH melebihi titik isoelektronik silika (pH = 2) melalui penambahan HMTA. Namun begitu penambahan berlebihan HMTA membawa kepada kemusnahan struktur SBA-15. Dalam perbandingan, dengan sampel Cu-SBA-15 yang disediakan melalui kaedah pengisitepuan, sampel Cu/SBA-15 yang disediakan melalui pengubahan pH adalah lebih aktif bagi aktiviti penguraian bermangkin N2O berdasarkan 80% penukaran N2O pada suhu 550 C dan mencapai 100% pada suhu 600 °C. Tenaga pengaktifan bagi tindak balas yang dimangkinkan Cu/SBA-15 kaedah penggabungan adalah 91.9 - 121.6 kJ/mol iaitu lebih rendah berbanding dengan nilai bagi Cu/SBA-15 kaedah pengisitepuan iaitu di antara 148.5 - 173.9 kJ/mol. Dengan kehadiran CH4, Cu/SBA-15 disediakan dengan menggunakan kaedah pengubahsuaian pH telah menunjukkan aktiviti pemangkinan yang lebih tinggi. Penguraian lebih daripada 80% penukaran dicapai pada 500 C bagi tindak balas penurunan N2O dengan CH4.
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TABLE OF CONTENTS
Page
DECLARATION
TITLE PAGE
DEDICATION
ACKNOWLEDGMENT
ABSTRACT
ABSTRAK
TABLE OF CONTANTS
LIST OF TABLES
LIST OF FIGURES
LIST OF ABBREVIATIONS
i
ii
iii
iv
v
vi
x
xii
xxi
CHAPTER 1 GENERAL INTRODUCTION
1.1 Introduction
1.2 N2O Emission
1.3 Catalytic Removal of N2O Emissions
1.4 Mesoporous Silicate Types SBA-15
1.5 Problem Statement
1.6 Purpose of the Research
1.6.1 Objectives of the Research 1.6.2 Scopes of the Research
1.7 Outline of the Thesis
1
2
3
4
5
8
8 9
9
CHAPTER 2 LITERATURE REVIEW
2.1 Introduction
2.2 Background of Greenhouse Gases Emission
2.3 Background of N2O Emission
2.3.1 Chemistry of Nitrous Oxide 2.3.2 Nitrous Oxide as a Greenhouses Gases 2.3.3 N2O Emissions in the Industrial Processes 2.3.4 N2O emission control
11
13
15
15 16 18 20
vii
2.4 Catalytic Removal of N2O Emissions
2.4.1 Catalytic Decomposition of N2O 2.4.2 Mechanism of N2O Decomposition
2.4.3 Catalytic Reduction of N2O
2.5 Porous Materials
2.6 Mesoporous Molecular Sieves
2.7 Mesoporous Silicate Types SBA-15.
2.7.1 The Synthesis of SBA-15 2.7.2 Mechanism for the Formation of SBA-15 2.7.3 The Characterisation of SBA-15 2.7.4 The Application of SBA-15.
2.8 Metal Incorporated SBA-15.
20
20 24 25
26
27
28
29 30 31 32
33
CHAPTER 3 EXPERIMENTAL METHODS
3.1 Introduction
3.2 Catalyst Preparation
3.2.1 Preparation of SBA-15 3.2.2 Preparation of M/SBA-15 materials by impregnation
method 3.2.3 Preparation of Selected Transition Metal incorporated
SBA-15 3.2.3.1 Different acidity condition 3.2.3.2 pH modified condition by addition of HMTA
3.2.3 Preparation of Metal Oxide in the SBA-15 by Physical Mixture Method
3.3 Characterisation
3.3.1 X-ray Diffraction 3.3.2 N2 adsorption-desorption Analysis 3.3.3 Transmission Electron Microscopy 3.3.4 Scanning Electron Microscopy 3.3.5 Elemental Analysis
3.2.5.1 Atomic absorption spectroscopy 3.3.5.2 Energy-dispersive X-ray spectroscopy
3.3.6 Fourier Transform Infrared Spectroscopy 3.3.7 Diffuse Reflectance UV-visible Spectroscopy 3.3.8 Thermogravimetric Analysis
3.3.9 X-ray photoelectron spectroscopy 3.3.10 Temperature Programmed Reduction
3.4 Catalytic Activities Studies
3.4.1 N2O decomposition 3.4.2 N2O reduction by CH4
37
39
39 40
40
40 40 41
42
42 45 46 46 47 47 47 48 49 50 50 51
52
52 53
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3.4.3 Kinetic studies 3.4.4 Stability Testing
53 53
CHAPTER 4 RESULTS AND DISCUSSION
4.1 Introduction
4.2 Synthesis of SBA-15 under different acidity
4.2.1 Results and Discussion 4.2.1.1 pH value 4.2.1.2 X-Ray Diffraction (XRD) 4.2.1.3 N2 adsorption-desorption analysis 4.2.1.4 Transmission Electron Microscopy (TEM) 4.2.1.5 Fourier Transform Infrared Spectroscopy (FTIR) 4.2.1.6 Thermogravimetric analysis (TGA)
4.2.2 Summary
4.3 Screening Study of Transition Metals on SBA-15
4.3.1 Results and Discussion 4.3.1.1 Elemental analysis 4.3.1.2 X-Ray Diffraction (XRD) 4.3.1.3 N2 adsorption-desorption analysis 4.3.1.4 Scanning Electron Microscope (SEM) 4.3.1.5 Catalytic activities for N2O decomposition 4.3.1.6 Kinetics Study on N2O decomposition
4.3.2 Summary
4.4 Copper Incorporated SBA-15 and Their Catalytic Activity
4.4.1 Effect of HCl concentration on Cu/SBA-15 4.4.2 Effect of addition HMTA on Cu/SBA-15 at different
Cu:Si molar ratio. 4.4.3 Effect of HMTA on Cu/SBA-15 prepared in different
acidic environment. 4.4.4 Effect of different HMTA:Si molar ratio on Cu/SBA-15 4.4.5 Summary
4.5 Comparative Study on Cu/SBA-15 Prepared Through Different Methods
4.5.1 Results and discussion 4.5.1.1 Element analysis 4.5.1.2 XRD analysis 4.5.1.3 Textural properties 4.5.1.4 TEM image 4.5.1.5 FT-IR analysis 4.5.1.6 UV-Vis analysis 4.5.1.7 TPR analysis 4.5.1.8 XPS analysis 4.5.1.9 Catalytic Activity for N2O decomposition
54
55
55 55 58 62 68 72 75 81
82
82 83 85 87 89 91 94 96
97
97 107
118
128 139
141
141 141 142 146 149 151 152 154 156 158
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4.5.1.10 Kinetic study of N2O decomposition for Cu-SBA-15
4.5.2 Summary
4.6 Catalytic Decomposition of N2O
4.6.1 Catalytic Decomposition versus Homogenous Decomposition
4.6.1.1 Homogenous N2O decomposition 4.6.1.2 Effect of pre-treatment on activity
4.6.2 N2O decomposition activity various Cu -SBA-15 4.6.3 Catalytic Activity of various Cu-SBA-15 catalysts for N2O reduction by CH4
4.6.3.1 Effect of different N2O:CH4 ratio 4.6.3.2 Effect of various copper-SBA-15 catalysts
4.6.4 The stability of various copper on SBA-15 for N2O decomposition reaction 4.6.5 Summary
160
162
163
163
163 164 167 169
169 171 175
177
CHAPTER 5 CONCLUSION AND RECOMMENDATION
5.1 Conclusion
5.2 Recommendation
178
180
REFERENCES
APPENDICES
181
191
A N2O, N2 and O2 analysis by Gas Chromatography 191
x
LIST OF TABLES
Table
Title Page
2.1 The Greenhouse Gases Atmospheric Lifetime and Global Warming Potential (GWP) and Radiative forcing
15
2.2 Metal incorporated SBA-15 preparation condition and catalytic activity.
34
4.1 The effect of preparation conditions of SBA-15 on pH values of reaction mixtures
56
4.2 Textural properties of SBA-15 samples prepared without and with addition of HMTA at different HCl concentration
63
4.3 Elemental analysis by AAS and EDX of SBA-15 and M/SBA-15 samples
83
4.4 2 of dominant peaks in of XRD patterns for M/SBA-15 samples
87
4.5 Unit cell parameter and texture properties of M/SBA-15 samples
88
4.6 Turnover frequency at different reaction temperature for decomposition of N2O over M/SBA-15
94
4.7 Activation energy (Ea) and pre-exponential factor (A) for the decomposition of N2O over M/SBA-15
95
4.8 pH values of Cu/SBA-15 samples prepared under different acidity without addition of HMTA.
97
4.9 Element analysis by AAS and EDX of Cu/SBA-15 samples prepared under different acidity without addition of HMTA
98
4.10 XRD analysis for Cu/SBA-15 samples prepared without addition HMTA in different acidity
100
4.11 Texture properties of Cu/SBA-15 (1:30) molar ratio sample prepared without addition HMTA in different acidity
101
4.12 pH values of Cu/SBA-15 sample preparation under different Cu:Si molar ratio with addition of HMTA in 0.10 M HCl
107
4.13 Elemental analyses by AAS and EDX of Cu/SBA-15 samples in 0.1 M HCL prepared under different Cu:Si molar ratio with addition of HMTA.
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4.14 XRD analysis for Cu/SBA-15 sample prepared with addition HMTA on different Cu/Si molar
110
4.15 Texture properties of Cu/SBA-15 samples prepared with addition HMTA under different Cu/Si molar ratio
112
4.16 pH values of Cu/SBA-15 sample preparation under different acidity with addition of HMTA
118
4.17 Element analysis by AAS and EDX Cu/SBA-15 sample preparation under different acidity with addition of HMTA
119
4.18 XRD analysis for sample prepared with HMTA addition on different acidity condition
121
4.19 Texture properties of Cu/SBA-15 samples prepared by addition of HMTA on different acidic environment
123
4.20 pH values of Cu/SBA-15 sample prepared under different HMTA:Si molar ratios
129
4.21 Element analysis by AAS and EDX of Cu/SBA-15 sample prepared under different HMTA:Si molar ratios
130
4.22 XRD analysis for Cu/SBA-15 sample prepared with addition HMTA on different HMTA:Si molar ratio
131
4.23 Texture properties of Cu/SBA-15 samples prepared with addition of HMTA on different HMTA:Si molar ratio
134
4.24 Element analysis of Cu/SBA-15 samples different method preparation
141
4.25 XRD analysis for Cu/SBA-15 samples different method preparation
145
4.26 Texture properties of Cu/SBA-15 samples different method preparation
146
4.27 Kinetic data for catalytic decomposition of N2O over Cu/SBA-15 samples prepared through different methods.
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LIST OF FIGURES
Figure
Title Page
2.1 The schematic of greenhouse effect
11
2.2 Concentrations of greenhouse gases over the last 2,000 years
12
2.3 The resonance structures of nitrous oxide
15
2.4 Human-related sources of N2O production
18
2.5 Schematic of the mesoporous silica SBA-15 synthesis
29
2.6 Interaction between hydrophilic ethylenede of polymeric templating agent Pluronic-123 and silicate source.
30
2.7 Basic characteristic of SBA-15
31
3.1 Flow chart representing overall experimental approach
38
3.2 Schematic drawing of the principle of X-ray diffraction
43
3.3 XRD pattern (a) Wide angles (b): Low angles XRD for SBA-15 samples
43
3.4 Instrumentation of Panalytical XPERT-PRO for XRD analysis
44
3.5 Instrumentation of of Micromeritics ASAP 2020 for N2 adsorption-desorption Analysis.
45
3.6 Instrumentation of FEI Tecnai G2 for TEM analysis.
46
3.7 Instrumentation of ZEISS EVO 50 for SEM analysis.
47
3.8 Instrumentation of PerkinElmer Spectrum One for FTIR analysis.
49
3.9 Instrumentation of Evolution 300 UV-Visible spectrophotometer for Diffuse reflectance.
49
3.10 Instrumentation of TA Instruments- TGA Q 500 for thermogravimetric analysis.
50
3.11 Instrumentation of Micromeritics AutoChem II 2920 for H2-TPR.
51
3.12 Schematic diagram of reaction test rig
52
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4.1 Small-angle XRD pattern of SBA-15 samples prepared under different acidity
59
4.2 Small-angle XRD pattern of SBA-15 samples prepared under different acidity with HMTA added after 6 hours hydrolysis
60
4.3 The small-angle XRD pattern of SBA-15 (0.1M)y prepared with addition of HMTA samples after 6 hours hydrolysis under different ratio of HMTA:Si
61
4.4 Small-angle XRD pattern of SBA-15 (0.1 M) samples prepared with HMTA added after under different duration time of hydrolysis
62
4.5 N2 adsorption–desorption isotherm (A) and pore size distribution (B) of SBA-15 samples prepared under different acidity
64
4.6 N2 adsorption–desorption isotherm (A) and pore size distribution (B) of SBA-15 samples prepared under different acidity with HMTA added after 6 hours of hydrolysis
65
4.7 N2 adsorption–desorption isotherm (A) and pore size distribution (B) of SBA-15 (0.1M)y samples prepared with HMTA addition after 6 hours hydrolysis under different ratio of HMTA:Si
66
4.8 N2 adsorption–desorption isotherm (A) and pore size distribution (B) of SBA-15 (0.1 M) samples prepared with HMTA added after under different duration time of hydrolysis
68
4.9 TEM image and histogram profile of samples SBA-15 samples under different acidity
69
4.10 TEM image and histogram profile SBA-15 samples prepared under different acidity with HMTA added after 6 hours of hydrolysis
70
4.11 TEM image and histogram profile of SBA-15 (0.1M)y samples prepared with addition of HMTA samples after 6 hours of hydrolysis under different ratio of HMTA:Si
71
4.12 The TEM image and histogram profile of SBA-15 (0.1 M) samples prepared with HMTA added after under different duration time of hydrolysis
72
4.13 The FT-IR spectra of SBA-15 samples preprared (A) different acidity, (B) different acidity with HMTA added, (C) SBA-15 (0.1M)y addition of HMTA in different ratio HMTA/Si (D) addition of HMTA after certain duration time of hydrolysis
73
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4.14 The FT-IR spectra of (a) HMTA (b) P123 (c) SBA-15 unwashed (d) SBA-15 washed and (e) SBA-15 calcined
74
4.15 TGA thermogram of (a) calcined SBA-15 (b) SBA-15 washed and (c) SBA-15 unwashed
76
4.16 DTG thermogram of (a) SBA-15 (b) SBA-15 washed and (c) SBA-15 unwashed
77
4.17 TEM image of samples SBA-15 prepared under different acidity condition
80
4.18 Plot of Surface Area and Pore Size of SBA-15 samples prepared under different pH value
81
4.19 Plot of Unit cell and Wall thickness of SBA-15 samples prepared under different pH value
81
4.20 EDX profiles of M/SBA-15 samples
84
4.21 Small-angle XRD pattern of M/SBA-15 samples
85
4.22 Wide-angle XRD pattern of M/SBA-15 samples
86
4.23 N2 adsorption–desorption isotherm of M/SBA-15 samples
88
4.24 The pore size distribution of M/SBA-15 samples
89
4.25 SEM images of M/SBA-15 samples
90
4.26 N2O conversion by SBA-15 and M/SBA-15 samples at different reaction temperatures
92
4.27 Arrhenius plot of ln K verses 1/T for N2O decomposition on various M/SBA-15 samples
95
4.28 The small-angle XRD pattern of Cu/SBA-15 (1:30) molar ratio without addition HMTA in different acidity
99
4.29 The wide-angle XRD pattern of Cu/SBA-15 (1:30) molar ratio without addition HMTA in different acidity.
100
4.30 N2 adsorption–desorption isotherm (A) and pore size distribution (B) Cu/SBA-15 (1:30) molar ratio sample prepared without addition HMTA in different acidity (a) SBA-15, (b) 2.0 M, (c) 1.0 M, (d) 0.10 M, (e) 0.01 M, and (f) 0.005M.
102
4.31 The SEM image of Cu/SBA-15 samples with (1:30) molar ratio sample prepared without addition HMTA in different
103
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acidity
4.32 The TEM image of Cu/SBA-15 samples with (1:30) molar ratio sample prepared without addition HMTA in differences acidity
104
4.33 The FTIR spectrum of Cu/SBA-15 samples with (1:30) molar ratio without addition HMTA in different acidity (a) SBA-15, (b) 2.0 M (c) 1.0 M, (d) 0.10 M, (e) 0.01 M, and (f) 0.005M.
105
4.34 The UV-vis spectrum of Cu/SBA-15 samples with (1:30) molar ratio in different acidity (a) SBA-15, (b) 2.0 M, (c) 1.0 M, (d) 0.10M, (e) 0.01 M, and (f) 0.005M.
106
4.35 The catalytic activity of N2O decomposition on Cu/SBA-15 sample with (1:30) molar ratio without addition of HMTA in different acidity
106
4.36 The small-angle XRD pattern of Cu/SBA-15 in 0.1M HCl with addition of HMTA in HMTA:Cu molar ratio 1:1 at different Cu/Si molar ratio
109
4.37 The wide-angle XRD pattern of Cu/SBA-15 samples in 0.1M HCl with addition of HMTA in HMTA:Cu molar ratio 1:1 at different Cu/Si molar ratio
111
4.38 The isotherm (A) and pore size distribution (B) of Cu/SBA-15 samples in 0.1M HCl with addition of HMTA in HMTA:Cu molar ratio 1:1 at different Cu/Si molar ratio ; (a) SBA-15, (b) 1:40, (c) 1:30, (d) 1:20, (e) 1:10, and (f) 1:5
112
4.39 The TEM image of Cu/SBA-15 samples in 0.1M HCl with addition of HMTA in HMTA:Cu molar ratio 1:1 at different Cu/Si molar ratio
113
4.40 The SEM image of Cu/SBA-15 samples in 0.1M HCl with addition of HMTA in HMTA:Cu molar ratio 1:1 at different Cu/Si molar ratio
114
4.41 The FTIR spectrum of Cu/SBA-15 samples in 0.1M HCl with addition of HMTA in HMTA:Cu molar ratio 1:1 at different Cu/Si molar ratio (a) SBA-15, (b) 1:40, (c) 1:30, (d) 1:20, (e) 1:10, and (f) 1:5
115
4.42 The UV-vis spectrum of Cu/SBA-15 samples in 0.1M HCl with addition of HMTA in HMTA:Cu molar ratio 1:1 at different Cu/Si molar ratio: (a) SBA-15, (b) 1:40, (c) 1:30, (d) 1:20, (e) 1:10, and (f) 1:5
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4.43 The catalytic activity of N2O decomposition on Cu/SBA-15 samples in 0.1M HCl with addition HMTA in HMTA:Cu molar ratio 1:1 at differences Cu/Si molar ratio: (a) SBA-15, (b) 1:40, (c) 1:30, (d) 1:20, (e) 1:10, and (f) 1:5
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4.44 The small-angle XRD pattern of Cu/SBA-15 molar ratio (1:30) samples with addition of HMTA (HMTA:Si molar ratio 1:10 ) in different acidity.
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4.45 The wide-angle XRD pattern of Cu/SBA-15 molar ratio (1:30) samples with addition HMTA (HMTA:Si molar ratio 1:10) in differences acidity.
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4.46 The isotherm (A) and pore size distribution (B) of Cu/SBA-15 molar ratio (1:30) samples with addition of HMTA (HMTA:Si molar ratio 1:10) in different acidity (a) SBA-15, (b) 2.0 M, (c) 1.0 M, (d) 0.10 M, (e) 0.01 M, and (f) 0.005 M.
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4.47 The TEM image of Cu/SBA-15 molar ratio (1:30) samples with addition of HMTA (HMTA:Si molar ratio 1:10 ) in different acidity
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4.48 The SEM image of Cu/SBA-15 molar ratio (1:30) samples with addition of HMTA (HMTA:Si molar ratio 1:10 ) in different acidity.
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4.49 The FTIR spectrum of Cu/SBA-15 molar ratio (1:30) samples with addition of HMTA (HMTA:Si molar ratio 1:10 ) in different acidity (a) SBA-15, (b) 2.0 M, (c) 1.0 M, (d) 0.10 M, (e) 0.01 M, and (f) 0.005 M.
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4.50 The UV-vis spectrum of Cu/SBA-15 molar ratio (1:30) samples with addition HMTA (HMTA:Si molar ratio 1:10 ) in different acidity (a) SBA-15, (b) 2.0 M, (c) 1.0 M, (d) 0.10 M, (e) 0.01 M, and (f) 0.005 M.
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4.51 The catalytic activity of N2O decomposition of Cu/SBA-15 molar ratio (1:30) samples with addition of HMTA (HMTA:Si molar ratio 1:10) in different acidity: (a) SBA-15, (b) 2.0 M, (c) 1.0 M, (d) 0.10 M, (e) 0.01 M, and (f) 0.005 M.
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4.52 The small-angle XRD pattern of Cu/SBA-15 molar ratio (1:30) samples in 0.1 M HCl with addition HMTA in different HMTA:Si molar ratio
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4.53 The wide-angle XRD pattern of Cu/SBA-15 molar ratio (1:30) samples in 0.1M HCl with addition HMTA in different HMTA:Si molar ratio.
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4.54 The isotherm (A) and pore size distribution (B) of Cu/SBA-15 molar ratio (1:30) samples in 0.1M HCl with addition of HMTA in different HMTA:Si molar ratio: (a) SBA-15, (b) 1:30, (c) 1:20, (d) 1:10 and (e) 1:5.
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4.55 The TEM image of Cu/SBA-15 molar ratio (1:30) samples in 0.1M HCl with addition of HMTA in different HMTA:Si molar ratio: (a) 1:30,(b) 1:20, (c) 1:10 and (d) 1:5.
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4.56 The SEM image of Cu/SBA-15 molar ratio (1:30) samples in 0.1M HCl with addition of HMTA in different HMTA:Si molar ratio:
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4.57 The FTIR spectrum of Cu/SBA-15 molar ratio (1:30) samples in 0.1M HCl with addition of HMTA in different HMTA:Si molar ratio: (a) SBA-15, (b) 1:30, (c) 1:20, (d) 1:10 and (e) 1:5.
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4.58 The UV-vis spectrum of Cu/SBA-15 molar ratio (1:30) samples in 0.1M HCl with addition HMTA in different HMTA:Si molar ratio: (a) SBA-15, (b) 1:30, (c) 1:20, (d) 1:10 and (e) 1:5.
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4.59 The catalytic activity for N2O decomposition on Cu/SBA-15 (1:30) molar ratio in 0.1M HCl with addition HMTA in different HMTA:Si molar ratio
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4.60 The small-angle XRD pattern of Cu/SBA-15 samples prepared by impregnation method at different Cu:Si molar ratio
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4.61 The small-angle XRD pattern of Cu/SBA-15samples prepared by pH modification method at different Cu:Si molar ratio
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4.62 The wide-angle XRD pattern of Cu/SBA-15 samples prepared by impregnation method at different Cu:Si molar ratio
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4.63 The wide-angle XRD patterns of Cu/SBA-15 samples prepared by pH modification method at different Cu:Si molar ratio.
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4.64 The isotherm (A) and pore size distribution (B) of Cu/SBA-15 samples prepared by impregnation method at different Cu:Si molar ratio: (a) SBA-15, (b) 1:70, (c) 1:50, (d) 1:30 and (e) 1:10.
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4.65 The isotherm (A) and pore size distribution (B) of Cu/SBA-15 samples prepared by pH modification method at different Cu:Si molar ratio: (a) SBA-15, (b) 1:70, (c) 1:50, (d) 1:30 and (e) 1:10.
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4.66 The TEM image of Cu/SBA-15samples prepared by impregnation method at different Cu:Si molar ratio.
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4.67 The TEM image of Cu/SBA-15 samples prepared by pH modification method at different Cu:Si molar ratio
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4.68 The FTIR spectrum of Cu/SBA-15 samples prepared by impregnation method at different Cu:Si molar ratio: (a) SBA-15, (b) 1:70, (c) 1:50, (d) 1:30 and (e) 1:10.
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4.69 The FTIR spectrum of Cu/SBA-15 samples prepared by pH modification method at different Cu:Si molar ratio: (a) SBA-15, (b) 1:70, (c) 1:50, (d) 1:30 and (e) 1:10.
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4.70 The UV-vis spectrum of Cu/SBA-15 samples prepared by impregnation method at different Cu:Si molar ratio: (a) SBA-15, (b) 1:70, (c) 1:50, (d) 1:30 and (e) 1:10.
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4.71 The UV-vis spectrum of Cu/SBA-15 samples prepared by pH modification method at different Cu:Si molar ratio: (a) SBA-15, (b) 1:70, (c) 1:50, (d) 1:30 and (e) 1:10.
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4.72 The TPR profile of Cu/SBA-15 samples prepared by impregnation method at different Cu:Si molar ratio: (a) 1:70, (b) 1:50, (c) 1:30 and (d) 1:10.
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4.73 The TPR profile of Cu/SBA-15 samples prepared by pH modification method at different Cu:Si molar ratio: (a) 1:70, (b) 1:50, (c) 1:30 and (d) 1:10.
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4.74 The XPS spectra of Cu/SBA-15 samples prepared by impregnation method at different Cu:Si molar ratio: (a) 1:70, (b) 1:50, (c) 1:30 and (d) 1:10.
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4.75 The XPS spectra of of Cu/SBA-15 samples prepared by pH modification method at different Cu:Si molar ratio: (a) 1:70, (b) 1:50, (c) 1:30 and (d) 1:10.
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4.76 The catalytic activity for N2O decomposition on Cu/SBA-15 samples prepared by impregnation method at different Cu:Si molar ratio.
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4.77 The catalytic activity for N2O decomposition on Cu/SBA-15 samples prepared by pH modification method at different Cu:Si molar ratio.
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4.78 Arrhenius plot of ln K verses 1/T for N2O decomposition on (A) Cu/SBA-15 prepared through impregnation method and (B) Cu/SBA-15 prepared through pH modification method at different Cu:Si molar ratio: (a) SBA-15, (b) 1:70, (c) (1:50),
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(d) (1:30) and (e) (1:10).
4.79 The catalytic activity for N2O decomposition on (a) blank samples, (b) SBA-15 and (c) Cu/SBA-15(1:30).
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4.80 Arrhenius plot of ln K verses 1/T for N2O decomposition in (a) homogeneous reaction, (b) catalysed by SBA-15 and (c) catalysed by Cu/SBA-15 (1:30).
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4.81 The catalytic activity for N2O decomposition on Cu/SBA-15 (1:30) at different pretreatment condition (a) without pre-treatment (b) pre-treatment with O2 (c) pre-treatment with He, and (d) pre-treatment with H2
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4.82 The catalytic activity of N2O decomposition on Cu/SBA-15 (1:30) at different catalysts loading (a) 0.100g (b) 0.200g, (c) 0.300g, and (d) 0.500g.
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4.83 The catalytic activity for N2O decomposition on Cu/SBA-15 (1:30) at different N2O mixture (a) 1% of N2O, (b) 3% of N2O, (c) 5% of N2O, and (d) 10 % of N2O.
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4.84 The catalytic activity of N2O decomposition on (a) SBA-15, (b) CuO-SBA-15 (1:30) physical mixture, (c) Cu-SBA-15 (1:30) impregnated, and (d) Cu/SBA-15(1:30) substituted
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4.85 N2O conversion, N2 and O2 formation against temperature on (a) Cu/SBA-15(1:30) substituted, (b) Cu-SBA-15 (1:30) impregnated, and (c) CuO-SBA-15 (1:30) physical mixtures
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4.86 Plotting graph of N2 and O2 formation verses N2O conversion of (a) Cu/SBA-15(1:30) substituted, (b) Cu-SBA-15 (1:30) impregnated, and (c) CuO-SBA-15 (1:30) physical mixtures
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4.87 The catalytic activity of N2O reduction by CH4 on Cu/SBA-15 (1:30) at different N2O:CH4 ratio (a) 1:0, (b) 1:1, (c) 4:1 and (d) 10:1.
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4.88 (a) CH4 conversion against Temperature and (b) Plotting N2O conversion verses CH4 conversion on Cu/SBA-15 (1:30) substituted at different N2O:CH4 ratio (a) 1:1, (b) 4:1 and (c) 10:1.
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4.89 The catalytic activity of N2O reduction by CH4 at N2O:CH4 (1:1) volume ratio on various copper condition of (a) SBA-15, (b) Cu/SBA-15 substituted, (c) Cu-SBA-15 impregnated, and (d) CuO-SBA-15 physical mixture
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4.90 The catalytic activity of N2O decomposition (- - -) and N2O reduction by CH4 (___) on various copper on SBA-15 (1:30) at N2O:CH4 (1:1) ratio for (a) Cu/SBA-15 substituted, (b) Cu-SBA-15 impregnated, (c) CuO-SBA-15 physical mixture and (d) SBA-15
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4.91 Arrhenius plot of ln K verses 1/T for N2O decomposition of (a) SBA-15 (b) Cu/SBA-15(1:30) substituted, (c) Cu-SBA-15 (1:30) impregnated, and (d) CuO-SBA-15 (1:30) physical mixtures.
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4.92 Arrhenius plot of ln K verses 1/T for N2O reduction by CH4 at N2O:CH4 (1:1) ratio on various copper condition of (a) SBA-15, (b) Cu/SBA-15 substituted, (c) Cu-SBA-15 impregnated and (d) CuO-SBA-15 physical mixture
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4.93 Stability test of N2O decomposition for (a) Cu/SBA-15 substituted, (b) Cu-SBA-15 impregnated, and (c) CuO-SBA-15 physical mixture
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4.94 Stability test of N2O reduction by CH4 for (a) Cu/SBA-15 substituted, (b) Cu-SBA-15 impregnated, and (c) CuO-SBA-15 physical mixture
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