Title Page
Contents
요약 11
ABSTRACT 13
CHAPTER 1. INTRODUCTION 15
1.1. Introduction of BiVO₄ 15
1.2. Introduction of antibiotics 19
1.3. Scope of the research 22
1.4. Organization of the Dissertation 23
CHAPTER 2. MATERIALS AND EXPERIMENTS 24
2.1. Materials 24
2.2. Synthesis of photocatalyst 25
2.2.1. Synthesis of BiVO₄ pine architectures 25
2.2.2. Synthesis of Pd decorated BiVO₄ 25
2.2.3. Synthesis of Pt/PtOₓ selectively decorated BiVO₄ 26
2.2.4. Synthesis of Pt/PtOₓ randomly decorated BiVO₄ 26
2.3. Characterization 26
2.4. Photocatalytic activity measurement 28
CHAPTER 3. RESULTS AND DISCUSSION 31
3.1. Characterization 31
3.1.1. Pd nanoparticles decorated BiVO₄ pine architectures 31
3.1.2. Pt/PtOₓ nanoparticles decorated BiVO₄ pine architectures 40
3.2. Photocatalytic activity 49
3.2.1. Pd nanoparticles decorated BiVO₄ pine architectures for degradation of SMX under visible light 49
3.2.2. Pt/PtOₓ nanoparticles decorated BiVO₄ pine architectures for degradation of SMX under visible light 72
CHAPTER 4. CONCLUSIONS 80
LIST OF PUBLICATION 82
LIST OF POSTERS 83
REFERENCES 84
Table 1.1. Comparison of photocatalytic degradation of MB for BiVO₄ pine and other BiVO₄ architectures. 18
Table 2.1. List of chemicals. 24
Table 2.2. The gradient elution. 29
Table 3.1. Pd content, bandgap energy, and rate constant of BiVO₄ and Pd-BiVO₄ composites. 33
Table 3.2. Results of TRPL data of Pd-BiVO₄ and BiVO₄. 38
Table 3.3. The values of the elements in equivalent circuit fitted in the Nyquist plots of Figure 3.10 A 39
Table 3.4. Properties of Pt 4f in the BiVO₄ and Pt/PtOₓ/BiVO₄ composites. 44
Table 3.5. Conduction band (CB) energy, valance band (VB) energy, bandgap energy (Eg), and rate constant of BiVO₄ and Pt/PtOₓ/BiVO₄ composites.[이미지참조] 45
Table 3.6. Results of TRPL data of BiVO₄ and Pt/PtOₓ/BiVO₄ composites. 47
Table 3.7. Photocatalytic degradation of sulfamethoxazole under visible light irradiation (300 W Xenon lamp and 420 UV cut-off filter) as a function of irradiation... 50
Table 3.8. Control experiments for stability test of 2.4% Pd-BiVO₄. Conditions: [2.4%Pd-BiVO₄]=50 mg, [Sulfamethoxazole]=10 ppm, V=100 mL. 53
Table 3.9. Comparison of photocatalytic degradation of SMX for Pd-BiVO₄ and other photocatalysts reported in the literature. 60
Table 3.10. Mass spectrometry pieces information and proposed structure for SMX. 71
Table 3.11. Rate constant Pt/PtOₓ/BiVO₄-PD composite over 5 times of reaction. 76
Figure 1.1. Band structure of photocatalyst and photoactivation process with the energy hν. 15
Figure 2.1. Images of BiVO4/ITO and 2.4% Pd-BiVO₄/ITO working electrodes. 28
Figure 3.1. A schematic diagram of the synthesis of Pd-BiVO₄ catalyst (A); SEM images of BiVO₄ (B1-3) and 2.4Pd%Pd-BiVO₄ (C1-3) catalysts; TEM image (D),... 31
Figure 3.2. SEM images of 1.2% Pd-BiVO₄ sample. 32
Figure 3.3. SEM images of 1.8% Pd-BiVO₄ sample. 32
Figure 3.4. SEM images of 3.0% Pd-BiVO₄ sample. 32
Figure 3.5. XRD patterns spectra of BiVO₄ and Pd-BiVO₄ catalysts. 34
Figure 3.6. XP spectra of BiVO₄ and 2.4% Pd-BiVO₄ samples. 34
Figure 3.7. A high-resolution XP spectra of Bi 4f (A), V 2p (B) and O 1s (C), and Pd 3d (D) of BiVO₄ and 2.4% Pd-BiVO₄ samples. 35
Figure 3.8. UV-vis DR spectra (A) and the corresponding Tauc's plots of BiVO₄ and Pd-BiVO₄ samples (B); Steady-state PL spectra (C), TRPL decay curves (D). 37
Figure 3.9. TRPL emission decay curves recorded for Pd-BiVO₄ and BiVO₄. τ is the lifetime calculated by fitting to a bi-exponential decay function. 38
Figure 3.10. EIS Nyquist plots (A) and EIS Mott-Schottky plots (B) of BiVO₄ and 2.4%Pd-BiVO₄ photoelectrodes; Schematic energy band diagram of BiVO₄ and... 39
Figure 3.11. Schematic of the synthesis of the BiVO₄ pine-like and Pt/PtOₓ/BiVO₄ composites. 40
Figure 3.12. SEM images of BiVO₄, Pt/PtOₓ/BiVO₄-R, Pt/PtOₓ/BiVO₄-PD catalysts. 41
Figure 3.13. XRD patterns of BiVO₄ and Pt/PtOₓ/BiVO₄ composites. 42
Figure 3.14. XPS survey of BiVO₄ and Pt/PtOₓ/BiVO₄ photocatalysts. 42
Figure 3.15. The high-resolution XP spectra of Bi 4f (A), V 2p (B), O 1s (C), and Pt 4f (D) of BiVO₄ and Pt/PtOₓ/BiVO₄ photocatalysts. 43
Figure 3.16. UV-Vis absorbance (A) and plot of photon energy (hν) and (αhν)¹/² (B) of BiVO₄ and Pt/PtOₓ/BiVO₄ composites.[이미지참조] 45
Figure 3.17. PL spectra (A) and TRPL (B) of BiVO₄ and Pt/PtOₓ/BiVO₄ composites. 46
Figure 3.18. TRPL decay curves and the TRPL emission decay curves recorded for BiVO₄ (A), Pt/PtOₓ/BiVO₄-R (B), and Pt/PtOₓ/BiVO₄-PD (C). 47
Figure 3.19. EIS-Nyquist plot (A) and Mott-Schottky (B) of BiVO₄ and Pt/PtOₓ/BiVO₄ photocatalysts. 48
Figure 3.20. Band diagram of BiVO₄, Pt/PtOₓ/BiVO₄-R, and Pt/PtOₓ/BiVO₄-PD samples. 49
Figure 3.21. Photocatalytic degradation of SMX and (A) and the first-order kinetics of SMX elimination (B) as a function of visible light irradiation time over BiVO₄... 50
Figure 3.22. The cycle test of SMZ photodegradation for 2.4% Pd-BiVO₄ sample. 53
Figure 3.23. XRD spectra of 2.4% Pd-BiVO₄ sample before and after the cycle test. 54
Figure 3.24. TEM image (A), STEM (B), and EDS elemental mapping images (C-F) of 2.4%Pd-BiVO₄ catalyst after photocatalytic test. 54
Figure 3.25. Leaching test (after adsorption for 60 min and photocatalysis for 30 min, the 2.4% Pd-BiVO₄ was filtered out). 55
Figure 3.26. TOC report for 2.4%Pd-BiVO₄ during photocatalytic degradation reaction at irradiation time 0 min. 56
Figure 3.27. TOC report for 2.4Pd%-BiVO₄ during photocatalytic degradation reaction at irradiation time 210 min. 57
Figure 3.28. TOC report for BiVO₄ during photocatalytic degradation reaction at irradiation time 0 min. 57
Figure 3.29. TOC report BiVO₄ during photocatalytic degradation reaction at irradiation time 210 min. 58
Figure 3.30. TOC removal of BiVO₄ and 2.4%Pd-BiVO₄ during photocatalytic degradation reaction. 58
Figure 3.31. Fluorescence EEM spectra of photocatalysts suspension after filtration treated with visible light irradiation for 0 (A), 15 (B), 30 (C), 60 (D), 90 (E), 150... 59
Figure 3.32. Effects of different scavengers on the photocatalytic degradation of sulfamethoxazole over 2.4%Pd-BiVO₄ and BiVO₄ catalysts under visible light irradiation. 62
Figure 3.33. Valence band spectra of BiVO₄ and 2.4% Pd-BiVO₄ samples. 63
Figure 3.34. Illustration of the photoexcited charge transfer with a Schottky barrier (A); Schematic illustration of the mechanism of photogenerated electron-hole... 64
Figure 3.35. Total ion chromatogram of SMX and extracted ion chromatograms for intermediates during photocatalytic degradation reaction at different time intervals (0 min). 65
Figure 3.36. Total ion chromatogram of SMX and extracted ion chromatograms for intermediates during photocatalytic degradation reaction at different time intervals (15 min). 66
Figure 3.37. Total ion chromatogram of SMX and extracted ion chromatograms for intermediates during photocatalytic degradation reaction at different time intervals (30 min). 67
Figure 3.38. Total ion chromatogram of SMX and extracted ion chromatograms for intermediates during photocatalytic degradation reaction at different time intervals (60 min). 67
Figure 3.39. Total ion chromatogram of SMX and extracted ion chromatograms for intermediates during photocatalytic degradation reaction at different time intervals (90 min). 68
Figure 3.40. Total ion chromatogram of SMX and extracted ion chromatograms for intermediates during photocatalytic degradation reaction at different time intervals (150 min). 69
Figure 3.41. Total ion chromatogram of SMX and extracted ion chromatograms for intermediates during photocatalytic degradation reaction at different time intervals (210 min). 70
Figure 3.42. Area evolution of SMX and intermediates (in positive mode). 70
Figure 3.43. Photodegradation of SMX (A), TOC removal efficiency and kobs (B) over BiVO₄ and Pt/PtOₓ/BiVO₄ composites. Condition: [catalyst dosage]=500 mg... 73
Figure 3.44. 3D EEMs spectra of SMX solution after treatment with Pt/PtOₓ/BiVO₄-PD photocatalyst for 0 (A), 15 (B), 30 (C), 60 (D), 90 (E), and 150 (F) min. 75
Figure 3.45. Cycling of SMX degradation over Pt/PtOₓ/BiVO₄-PD within 5 times of reaction. Condition: [catalyst dosage]=500 mg L⁻¹, [SMX]=10 ppm, V=0.1 L. 76
Figure 3.46. XRD patterns of Pt/PtOₓ/BiVO₄-PD before and after photocatalytic degradation of SMX (A). SEM image of Pt/PtOₓ/BiVO₄-PD sample after... 77
Figure 3.47. XPS spectra survey (A) and high-resolution XPS spectra of Pt 4f (B) of Pt/PtOₓ/BiVO₄-PD sample before and after photodegradation degradation of SMX. 77
Figure 3.48. Efficiency of SMX removal (A) and kobs of Pt/PtOₓ/BiVO₄-PD (B) in the presence of scavengers. Condition: [catalyst dosage]=500 mg L⁻¹, [SMX]=10...[이미지참조] 78
Figure 3.49. Mechanism of the photocatalytic of SMX degradation with Pt/PtOₓ/BiVO₄-PD composite. 79