Title Page
Contents
ABSTRACT IN KOREAN 11
Part Ⅰ. General Introduction 13
Ⅰ. WATER ELECTROLYSIS 13
1. Basics of Electrolysis 13
2. Mechanism of Hydrogen Evolution Reaction(HER) 16
3. Electrocatalytic parameters 17
Ⅱ. REFERENCES 19
Part Ⅱ. Experiment 21
Ⅰ. INTRODUCTION 21
Ⅱ. EXPERIMENTAL DETAILS 24
1. Reagents Information 24
2. Synthesis Methods 25
3. Structural characterization 28
4. Electrochemical Characterization 28
Ⅲ. RESULTS AND DISCUSSION 29
1. Surface Structure Modification via CoP Growth Control 29
2. Interface Modification via MoS₂ Phase Control 36
3. Stability test of Optimal conditon 45
Ⅳ. CONCLUSION 50
Ⅴ. REFERENCE 51
ABSTRACT 57
Table 1. Overpotential and tafel slope table of MoS₂(200)-CoP according to Co concentration in hydrothermal synthesis of Co(OH)F. 35
Table 2. HER performance of MoS₂-CoP according to growth temperature in hydrothermal synthesis of MoS₂. 41
Table 3. The comparison of the HER performance of MoS₂(200)-CoP and various reported electrocatalysts (at 10mA cm⁻²) in 1M KOH. 43
Figure 1. Illustration of electrochemical water splitting reaction in acidic and alkaline condition. 15
Figure 2. Synthesis scheme. 27
Figure 3. Illustration of furnace arrangement at Phophorization process. 27
Figure 4. (a-f) SEM images of CoP according to time in hydrothermal synthesis of Co(OH)F. Scale bar is 5μm. 30
Figure 5. (a-d) SEM images of MoS₂(200)-CoP according to Co concentration in hydrothermal synthesis of Co(OH)F. Scale... 32
Figure 6. XRD graph of MoS₂(200)-CoP according to Co concentration in hydrothermal synthesis of Co(OH)F. 33
Figure 7. LSV curve of MoS₂(200)-CoP according to Co concentration in hydrothermal synthesis of Co(OH)F. 35
Figure 8. (a-f) SEM images of MoS₂ according to growth temperature in hydrothermal synthesis of MoS₂. Temperature(℃): 160, 170, 180, 200, 220, 240. 37
Figure 9. Raman graph of MoS₂ according to growth temperature in hydrothermal synthesis of MoS₂. Temperature(℃): 160, 180, 200, 220, 240. 38
Figure 10. XPS graph of Mo 3d of MoS₂ according to growth temperature in hydrothermal synthesis of... 39
Figure 11. LSV curves of MoS₂-CoP in 1M KOH according to growth temperature in hydrothermal synthesis of MoS₂. 41
Figure 12. Overpotential of MoS₂-CoP(at 1M KOH, 10mA cm⁻²) and 1T ratio according to growth temperature in hydrothermal synthesis of MoS₂. 42
Figure 13. Full water splitting at H-type cell of MoS₂(200)-CoP. 44
Figure 14. Illustration of full water splitting at H-type cell. 44
Figure 15. LSV curve graph of CoP and MoS₂(200)-CoP stability test in 1M KOH(Before and After CV 10000 cycle). 46
Figure 16. Raman graph of CoP and MoS₂(200)-CoP stability test in 1M KOH(Before and After CV 10000 cycle). 47
Figure 17. SEM image of MoS₂(200)-CoP and CoP before and after stability test in 1M KOH(Scale bar is 2μm). 48
Figure 18. Chronoamperometry(CA) graph at-1.25V for 24 hours of MoS₂(200)-CoP in 6M 60℃ KOH. 49