Title Page
ABSTRACT
Contents
NOMENCLATURES 12
Chapter 1. INTRODUCTION 13
1.1. Graphitic Carbon Nitride - based photocatalysis 13
1.2. Hydrothermal method 14
1.3. Doping method 14
1.4. Photodegradation of tetracycline hydrochloride antibiotic 15
1.5. Water splitting photocatalyst for H₂ evolution reaction 16
1.6. Research objectives 18
Chapter 2. MATERIALS AND METHOD 19
2.1. Catalyst preparation 19
2.2. Characterization 21
2.3. Photocatalytic activity 22
2.3.1. Photodegradation test 22
2.3.2. H₂ evolution reaction test 23
Chapter 3. RESULTS AND DISCUSSION 24
3.1. The growth of extended melem units 24
3.1.1. Physicochemical properties 24
3.1.2. Optical properties of modified g-C₃N₄ 31
3.1.3. Photodegradation performance 34
3.1.4. Conclusion 39
3.2. The O and P co-doped effect on the H₂ evolution reaction 40
3.2.1. Physicochemical and morphological properties 40
3.2.2. Optical properties of modified OyPCNUPt[이미지참조] 49
3.2.3. H₂ evolution performance 53
3.2.4. Conclusion 55
Chapter 4. CONCLUSION 56
References 57
Table 1. Specific surface area, pore volume, and average pore size of photocatalysts were determined via N₂ adsorption-desorption isotherm measurements. 25
Table 2. C/N and O/N atomic ratios of all prepared samples were obtained from elemental analysis. 30
Table 3. Kinetic rate constants (k) and correlation coefficients (r²) of TC photodegradation. 36
Table 4. Specific surface area, pore volume, and average pore diameter of all synthesized samples were determined via N₂ adsorption-desorption isotherm measurements. 41
Table 5. N, C, O, and Pt content, and the atomic ratio of photocatalysts. 47
Table 6. Fitted parameters of CNUPt, O₁.₅PCNUPt, O₂.₅PCNUPt, and O₃.₅PCNUPt for the Nyquist plots.[이미지참조] 52
Figure 1. Tetracycline Hydrochloride structure. 16
Figure 2. The Global total consumption by source and CO₂ emissions from fuel combustion in 2019 17
Figure 3. The synthesis of CN, CN-180-x, and CN-200-6. 19
Figure 4. The synthesis of OyPCNUPt catalysts.[이미지참조] 20
Figure 5. N₂ adsorption/desorption isotherms of as-prepared photocatalysts. 25
Figure 6. TEM images of CN-180-3 (a), CN-180-6 (b,e), CN-180-9 (c), and CN-200-6 (d). 26
Figure 7. (A) XRD patterns and (B) FT-IR spectra of CN-180-x and CN-200-6 samples. 28
Figure 8. XPS data of C 1s, N 1s, and O 1s for all the photocatalysts. 30
Figure 9. (A) UV-Vis DRS absorption spectra, (B) Tauc plots for the band gap, (C) the EIS Nyquist plots, and (D) time-resolved fluorescence decay spectra in the ns time scale with excitation... 32
Figure 10. Band diagrams of the CN-180-x and CN-200-x photocatalysts. 33
Figure 11. Photodegradation efficiency of TC by CN-180-x and CN-200-6 under visible light irradiation (140W xenon lamp, λ〉 420nm) (A) C/C₀ vs. t (Initial condition: 20 mg L⁻¹ TC, 0.2 g... 35
Figure 12. (A) The pseudo-first-order reaction kinetics and (B) rate constants (k) of as-prepared photocatalysts for TC photodegradation. 37
Figure 13. Recycling ability evaluation of CN-180-6. 38
Figure 14. The influence of reactive species on TC removal efficiency. 39
Figure 15. The N₂ adsorption-desorption isotherm and the corresponding pore diameter distribution (insert) of photocatalysts. 41
Figure 16. (A) FT-IR spectra and (B) XRD patterns of photocaalysts. 43
Figure 17. FE-SEM images of CNUPt (a,b), O₁.₅PCNUPt (c,d), O₂.₅PCNUPt (e,f), and O₃.₅PCNUPt (g,h).[이미지참조] 45
Figure 18. STEM images and Pt diameter (nm) of CNUPt (a), O₁.₅PCNUPt (b), O₂.₅PCNUPt (c), and O₃.₅PCNUPt (d).[이미지참조] 46
Figure 19. XPS data of C 1s, N 1s, O 1s, P 2p, and Pt 4f for all the photocatalysts. 48
Figure 20. Atomic percentage of (A) O-containing functional groups and (B) Pt valence state. 49
Figure 21. (A) UV-Vis DRS absorption spectra, (B) Tauc plots for the band gap, (C) the PL spectra, and (D) the EIS Nyquist plots of OyPCNUPt photocatalysts.[이미지참조] 51
Figure 22. (A) XPS-VB spectra and (B) band structure diagram of the synthesized samples. 52
Figure 23. (A) Hydrogen evolution performance (µmol. g⁻¹), (B) Hydrogen evolution rate (µmol. g⁻¹ .h⁻¹) of OyPCNUPt, and (C) recycle test of O₂.₅PCNUPt.[이미지참조] 54
Figure 24. A schematic formation of CNuPt, O₂.₅PCNUPt, and O₃.₅PCNUPt (before and after Pt loading).[이미지참조] 55