Title Page
ABSTRACT
Contents
LIST OF ABBREVIATIONS 11
CHAPTER 1. INTRODUCTION 12
1.1. Introduction to Electrocatalysis 12
1.2. Oxygen Evolution Reaction (OER) 13
1.3. Previous & Recent Trends of Electrocatalysts 14
1.4. Strategies to improve electrocatalytic activity. 15
1.5. Transition Metal-Based Materials & Heterostructure 17
1.6. Techniques for thin film fabrication 19
1.7. Objectives of this Research 20
CHAPTER 2. METHODOLOGY 22
2.1. Materials selection 22
2.2. Experimental setup 22
2.3. Summary of process parameters 24
2.4. Characterization of thin films 24
2.5. Electrocatalytic activity analysis 26
CHAPTER 3. ELECTROCATALYTIC RESULTS 28
3.1. Electrochemical active surface area 28
3.2. Electrocatalytic Activity of Heterostructure Electrode 29
CHAPTER 4. THIN FILM CHARACTERIZATION 34
4.1. Images of thin films 34
4.2. XRD ANALYSIS 34
4.3. SEM ANALYSIS 36
4.4. RAMAN ANALYSIS 40
4.5. XPS ANALYSIS 44
CHAPTER 5. CONCLUSION 50
REFERENCES 51
Table 1. Process parameters for Ni(OH)₂ & MoS₂ on NF substrate. 24
Table 2. Values of h, Tafel slope, Rct, and ECSA of the modified electrode with Ni(OH)₂ -MoS₂ NCs at various MoS₂ contents.[이미지참조] 33
Table 3. Identification of active Raman modes in the nanostructured Ni(OH)₂-MoS₂ heterostructure electrodes at various MoS₂ Content. 44
Table 4. XPS peaks positions estimated from the deconvolution of XPS scans 49
Figure 1. schematic presentation of Electrocatalysis 14
Figure 2. Techniques to improve electrocatalytic activity. 16
Figure 3. Objectives of this research. 21
Figure 4. Schematic for the vacuum kinetic spray method (NPDS) 23
Figure 5. OER LSV curve (a), Tafel plots (b), Nyquist Plot(c), current density vs scan rate in non-faradic region 29
Figure 6. Stability test for 50 hours(a), LSV curve after the stability test (b) 32
Figure 7. Deposited thin films. 34
Figure 8. XRD patterns of Ni(OH)₂-MoS₂ composites in powder form (a) and thin film deposited on nickel foam (b) 35
Figure 9. SEM images of Ni(OH)₂ Powder (a, b), MoS₂ Powder (c, d),75% MoS₂ (e, f) 38
Figure 10. SEM images of Ni(OH)₂/NF (a, b), MoS₂/NF (c, d),75% MoS₂/NF (e, f) 39
Figure 11. Raman Spectra of powder and thin film respectively. Ni(OH)₂ (a, b), MoS₂ (c, d),75% MoS₂ (e, f) 41
Figure 12. Deconvoluted Mo 3d XPS scan of pure MoS₂ (a), 75 % MoS₂ heterostructure 45
Figure 13. Deconvoluted Ni 2p XPS scan of Pure Ni(OH)₂(a), 75% MoS₂ heterostructure(b) 46
Figure 14. Deconvoluted O 1s XPS scan of pure Ni(OH)₂ (a), 75%MoS₂ (b) 47
Figure 15. Deconvoluted S 2p XPS scan of pure MoS₂ (a), 75 % MoS₂ heterostructure thin film (b) 48