One-step synthesis of g-C3N4 nanosheets with improved photocatalytic performance for organic dye degradation under visible light irradiation
- Abstract
- Graphitic carbon nitrides (g-C3N4) have received much attention as a visible-light respond photocatalyst due to a wide range of possible applications. However, its activity could not meet expectations due to the fast recombination of photogenerated electron-hole pairs and low specific surface area. Many studies have developed to solve these issues, such as doping with a noble metal, constructing nanocomposites with heterostructures based on g-C3N4, and controlling its morphologies. In these methods, morphology control has been considered a valuable approach for enhancing the efficiency of g-C3N4 photocatalyst because its specific surface area can be increased. For example, researchers used g-C3N4 bulk to prepare g-C3N4 nanosheets using several methods, such as thermal etching and ultrasonic-assisted, using hard or soft templates or chemical etching. Compared to bulk g-C3N4, g -C3N4 nanosheets have more incredible photocatalytic performance. In our study, g-C3N4 nanosheets were synthesized by a one-step thermal treatment of melamine in the presence of ammonium salts such as NH4Cl, (NH4)2SO4, CH3COONH4. The characterizations of surface morphology and optical properties of all g-C3N4 samples were investigated by X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR), transmission electron microscopy (TEM), UV-visible diffuse reflectance spectroscopy. The as-synthesized g-C3N4 nanosheets exhibited excellent photocatalytic performance under visible light irradiation with about 98% RhB removal after 210 min compared to bulk g-C3N4. The effect of catalyst dosage, pH, and concentration of RhB on the degradation efficiency using g-C3N4 nanosheets was also investigated. According to the scavenging experiment, h+ and •O2− species were demonstrated as the critical reactive species for the RhB. Therefore, our investigation may provide a facile and efficient way to synthesize the g-C3N4 nanosheets with a high specific surface area for environmental decontamination.
- Issued Date
- 2022
- Awarded Date
- 2022. 8
- Type
- Dissertation
- Publisher
- 부경대학교
- Affiliation
- Pukyong National University, Graduate School
- Department
- 대학원 지구환경시스템과학부환경공학전공
- Advisor
- Tae Yoon Lee
- Table Of Contents
- CHAPTER 1: INTRODUCTION 1
1.1 Introduction of photocatalyst 1
1.2 Introduction of graphitic g-C3N4 5
1.3 Scope of the research 9
1.4 Organization of the Thesis 9
CHAPTER 2: MATERIALS AND EXPERIMENTS 10
2.1 Materials 10
2.2 Synthesis of catalysts 10
2.2.1 Synthesis of bulk g-C3N4 10
2.2.2 Synthesis of CN-nanosheets using melamine and ammonium chloride 11
2.2.3 Synthesis of g-C3N4 modified with different ammonium salts. 12
2.3 Characterization 12
2.4 Photocatalytic activity test for rhodamine B 13
2.5 Active species trapping experiments 13
CHAPTER 3: RESULTS AND DISCUSSION 14
3.1 Characterization 14
3.1.1 CN-Nanosheets 14
3.1.2 g-C3N4 modified using different ammonium salts 22
3.2 Photocatalytic activity test 29
3.2.1 CN-nanosheets for degradation of Rhodamine B under visible light 29
3.2.2 g-C3N4 modified using different ammonium salts 42
CHAPTER 4: CONCLUSION 56
REFERENCES 59
- Degree
- Master
- Appears in Collections:
- 대학원 > 지구환경시스템과학부-환경공학전공
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