Development of z scheme heterojunction type II photocatalysts for efficient degradation of pollutants under solar light irradiation

Ph.D Thesis Development of Z-scheme heterojunction Type II photocatalysts for efficient degradation of pollutants under solar light irradiation Graduate School of Yeungnam University Department of Chemical Engineering Major in Chemical Engineering NGUYEN VAN QUANG Advisor: Prof Jae-Jin Shim August 2021 Ph.D Thesis Development of Z-scheme heterojunction Type II photocatalysts for efficient degradation of pollutants under solar light irradiation Advisor: Prof Jae-Jin Shim Presented as Ph.D Thesis August 2021 Graduate School of Yeungnam University Department of Chemical Engineering Major in Chemical Engineering NGUYEN VAN QUANG Nguyen Van Quang’s Ph.D Dissertation is approved Committee member Prof Moonyong Lee, Ph.D _ _ Committee member Prof Jae-Jin Shim, Ph.D _ Committee member Prof Taeho Yoon, Ph.D Committee member Prof Jinwoo Lee, Ph.D _ Committee member Prof Dohyung Kang, Ph.D _ August 2021 Graduate School of Yeungnam University THƯ VIỆN TRƯỜNG ĐẠI HỌC BÁCH KHOA – ĐẠI HỌC ĐÀ NẴNG Lưu hành nội Acknowledgments Firstly, I would like to express gratitude from the bottom of my heart to my supervisor Prof Jae-Jin Shim for his guidance, sincere advice, and supports during my stay for combined Master and Ph.D program at Nano Energy Materials and Processing lab (formerly, Supercritical Fluids and Nano Processing Lab) I would also like to thank the committee members: Prof Moonyong Lee, Prof Taeho Yoon, Prof Jinwoo Lee (KAIST), and Prof Dohyung Kang for useful and valuable recommendation on my dissertation and final defense Secondly, I would like to give my gratitude to postdocs and research professors in NanoEMAP lab: Dr Hoa, Dr Ranjith, Dr Amr, Dr Rabie, Dr Manjiri, Dr Shafi, Dr Darshna, Dr Kathik, and Dr Debananda for their sharing of knowledge and research experience I would like to express my thanks to the past and present lab members: Dr Marjorie, Dr Toan, Mr Mostafa, Mr Ganesh, Ms Tensangmu, Mr Abebaw, Mr Chinh, Mr Tue, Ms Lamiel, Mr Sarmad, Mr Olvianas, Mr Umer, Mr Jinho, who shared their study experience and helped me in the life in Korea I am also grateful to the Graduate School of Yeungnam University, which provided me with full scholarship for my combined Master and Ph.D course, and the BK21+ Program for the financial support during my stay in Yeungnam University Further, I would like to thank my senior staff from Building Material Division, Faculty of Bridge and Road engineering, and close friends (Mr Quang Hung, Mr Minh Hoang, Ms Minh Tri, Mr Van Thanh, Ms Thi Phuong, Mr Manh Hung ) from Vietnam and (Mr Van Dung, Mr Van Nam, Ms Vinh Quy) in Korea for their company and encouragement during my stay in Korea Special thanks as well to Prof Doan Quang Vinh (Rector of University of Science and Technology-The University of Danang), Dr Huynh Phuong Nam (Head of Department of Personal Management-The University of Danang), Dr Cao Van Lam (Dean of Faculty of Bridge and Road Engineering, University of Science and Technology-The University of Danang) for their unwavering support from Vietnam towards the completion of my doctoral degree To 사모님, Prof Shim’s wife, for her best regards to me and great Korean meals Lastly, I am very grateful to my lovely family for special care, love, encouragement, and supports I would like to thank my parents (Dieu Nguyen, Thi Be Nguyen), my siblings (Hung i THƯ VIỆN TRƯỜNG ĐẠI HỌC BÁCH KHOA – ĐẠI HỌC ĐÀ NẴNG Lưu hành nội Nguyen, Thi Nguyet Nguyen, Thi Nga Nguyen, Son Nguyen), my brothers and sisters-in-law (Phu Trong Nguyen, Day Pham, Thi Nga Hoang, Thi Hang Vo) and all my nephews and nieces Thank you for beautiful memories with all of you in Korea Nguyen Van Quang Yeungnam University Republic of Korea August 2021 THƯ VIỆN TRƯỜNG ĐẠI HỌC BÁCH KHOA – ĐẠI HỌC ĐÀ NẴNG Lưu hành nội ii THƯ VIỆN TRƯỜNG ĐẠI HỌC BÁCH KHOA – ĐẠI HỌC ĐÀ NẴNG Lưu hành nội Abstract Recently, the Z-scheme photocatalytic system has attracted more attention in the photocatalyst designs for environmental remediation applications Compared with conventional designs of the photocatalysts, the Z-scheme-based design has been selected as an ideal solution to improve the photocatalytic activity and stability of the catalysts This Z-scheme photocatalytic system not only reduces the recombination of photoinduced electrons and holes but also maintains a prominent redox ability This dissertation builds up the story of various photocatalytic systems from the simple construction of ZnO/graphene to the Zscheme-based construction among semiconductors (TiO2, C-MoS2, BiPO4, BiOCl, Ag/AgBr, BiOBr, and Bi2O3) For each photocatalytic system, the synthesis method, characterization, and photocatalytic activities of the photocatalysts in the degradation of organic pollutants, such as methylene blue (MB), rhodamine B (RhB), and methyl orange (MO), tetracycline hydrochloride (TCH), hydroxychloroquine (HCQ) in water are presented In addition, the mechanism of pollutant degradation at each photocatalytic system was also discussed iii In Chapter 2, the nanospherical ZnO/rGO composite synthesized by a twostep method showed the high MB and RhB removal efficiencies and good stability under UV light In Chapter 3, a Z-scheme heterojunction photocatalyst of C-MoS2/TiO2 nanocomposite was prepared by a two-step hydrothermal method (high temperature and high pressure) The Z-scheme photocatalyst exhibited the improvement of photocatalytic activity in the degradation of MB, RhB, and TCH under solar light In Chapter 4, a facile and rapid microwave-assisted one-step method was used to synthesize the Z-scheme ternary photocatalyst of silk cocoon-like BiPO4 on BiOBr/Bi2O3 nanosheets The Z-scheme charge transfer mechanism among three bismuth-based components resulted in a stronger enhancement of RhB degradation under solar light The photocatalyst also performed good photocatalytic activity towards the TCH, HCQ, and MO pollutants under solar light Following the same synthesis method as in Chapter 4, the Z-scheme ternary photocatalyst of layer-structured BiOCl/BiOBr/Bi2O3 nanocomposite was prepared and the excellent photocatalytic activity and good stability of the catalyst were demonstrated in the degradation of RhB dye with high dye iv concentration under visible and solar light Moreover, this Z-scheme photocatalyst also showed good photocatalytic activity for TCH and MO pollutants Chapter presents the synthesis of Z-scheme quaternary photocatalyst of Ag/AgBr@BiOBr/Bi2O3 nanocomposite using the same method as described in Chapters and This quaternary photocatalyst is highly efficient in degrading the MO dye with high removal efficiency and excellent stability under visible light The photocatalyst also showed the good photocatalytic activity for RhB and TCH under different light sources: Light-emitting diode (LED), halogen lamp (from an overhead projector), and simulated solar light In addition, the rapid microwave-assisted one-step method could be used in the large-scale processes for synthesizing the good Z-scheme photocatalysts for the field of environmental remediation because the method is facile, fast, and controllable Table of Contents Acknowledgments i Abstract iii Table of Contents vi List of Figures v viii List of Schemes xvi List of Tables xviii Chapter Introduction 1.1 Research Objectives 1.2 Dissertation Outline Chapter Solvent-driven morphology-controlled synthesis of highly efficient long-life ZnO/graphene nanocomposite photocatalysts for the practical degradation of organic wastewater under solar light 2.1 Introduction 2.2 Experimental 10 2.3 Results and Discussions 16 2.4 Conclusions 51 Chapter Synthesis of (101)-faceted octahedral TiO2 wrapped with MoS2/C as visible light driven Z-scheme photocatalyst for the degradation of organic pollutants 54 3.1 Introduction 54 3.2 Experimental 57 3.3 Results and Discussions 63 3.4 Conclusions 91 Chapter Facile microwave-assisted synthesis of Z-scheme of silk cocoon-like BiPO4 on BiOBr/Bi2O3 nanosheets for degradation of organic pollutants under solar light 92 4.1 Introduction 92 4.2 Experimental 95 4.3 Results and Discussions 99 4.4 Conclusions 117 vi Figure A2.7 SEM images of ZnO particles synthesized in the absence of GO at three ethanol-to-water solvent ratios (a) R = 1:1, (b) R = 1:0.25, and (c) R = 1:0 Figure A2.8 TEM images of (a) GO, (b) ZnO seed/RGO, and (c,d) asprepared ZnO/RGO (sZG) samples at different magnifications 201 THƯ VIỆN TRƯỜNG ĐẠI HỌC BÁCH KHOA – ĐẠI HỌC ĐÀ NẴNG Lưu hành nội Figure A2.9 Tauc plots of the ZnO/RGO nanocomposites (sZG, rZG, and dZG) and the pure ZnO Figure A2.10 Adsorption of the MB solution (10 mg L-1) on the sZG and asprepared ZnO catalyst for h under dark condition 202 THƯ VIỆN TRƯỜNG ĐẠI HỌC BÁCH KHOA – ĐẠI HỌC ĐÀ NẴNG Lưu hành nội Figure A2.11 Comparison of the photocatalytic degradations of a 10 mg L1 MB solution in the presence of sZG, sZG*, dZG*, and rZG* nanocomposites after 60 under UV irradiation Figure A2.12 MB degradation efficiency after 60 of UV irradiation using sZG nanocomposite (0.1 g L-1) synthesized without HMTA for 24 h (S0) and with HMTA at various reaction times: 12 h (S1), 18 h (S2), 24 h (S3), and 36 h (S4) 203 THƯ VIỆN TRƯỜNG ĐẠI HỌC BÁCH KHOA – ĐẠI HỌC ĐÀ NẴNG Lưu hành nội Figure A2.13 SEM images of the rZG, dZG, and sZG nanocomposites prepared at different reaction times (12 h and 24 h) Figure A2.14 Dye degradation efficiency of the rZG, dZG, sZG nanocomposites after 60 under UV irradiation (10 mg L–1 dye solution, 0.1 g L–1 catalyst loading, and 40-W UV lamp power) 204 THƯ VIỆN TRƯỜNG ĐẠI HỌC BÁCH KHOA – ĐẠI HỌC ĐÀ NẴNG Lưu hành nội Figure A3.1 SEM image of K2Ti6O13 nanowires (a) and TEM image of MST sample (b) Figure A3.2 TGA of the C-MoS2/TiO2 sample (CMST) (a) and MoS2 sample (b) Figure A3.3 UV-vis diffuse reflectance spectra of TiO2 and CMS samples 205 THƯ VIỆN TRƯỜNG ĐẠI HỌC BÁCH KHOA – ĐẠI HỌC ĐÀ NẴNG Lưu hành nội Figure A3.4 Tauc plots (a and b) and valence band-XPS spectra (c and d) of the TiO2 and CMS samples Figure A3.5 Point of zero charge of C-MoS2/TiO2 (CMST) 206 THƯ VIỆN TRƯỜNG ĐẠI HỌC BÁCH KHOA – ĐẠI HỌC ĐÀ NẴNG Lưu hành nội Figure A4.1 XRD patterns of BiPO4 and Bi2O3 samples Figure A4.2 XRD patterns of BiOBr sample 207 THƯ VIỆN TRƯỜNG ĐẠI HỌC BÁCH KHOA – ĐẠI HỌC ĐÀ NẴNG Lưu hành nội Figure A4.3 VB-XPS of BiPO4 sample Figure A5.1 XRD patterns of BiOCl/Bi2O3 sample 208 THƯ VIỆN TRƯỜNG ĐẠI HỌC BÁCH KHOA – ĐẠI HỌC ĐÀ NẴNG Lưu hành nội Figure A5.2 Tauc plot (a) and VB-XPS (b) of BiOCl sample Figure A6.1 Photodegradation curves of 10 mg L–1 TCH in the presence of Ag/AgBr@BiOBr/Bi2O3 catalysts (samples S1, S3, S5, S7, and S10 synthesized using 100, 300, 500, 700, and 1000 l of 0.1 M AgNO3 solution, respectively Photodegradation conditions: catalyst loading of 0.5 g L−1, 10 mg L−1 TCH, 150 W Xe lamp-solar simulator) 209 THƯ VIỆN TRƯỜNG ĐẠI HỌC BÁCH KHOA – ĐẠI HỌC ĐÀ NẴNG Lưu hành nội Figure A6.2 Adsorption kinetics of Ag/AgBr@BiOBr/Bi2O3 sample with three different pollutants in the dark (Catalyst loading of 0.3 g L−1, initial pollutant concentrations of 10 mg L−1) Figure A6.3 Comparison of the photocatalytic performance (a) and reusability (degradation efficiency after reuse cycles) (b) in the MO degradation of Ag- and Bi-containing photocatalysts reported in the literature and this work [1] B Xu, Y Li, Y Gao, S Liu, D Lv, S Zhao, H Gao, G.Yang, N Li, L Ge, Appl Catal B Environ 2019, 246, 140–148 DOI: 10.1016/j.apcatb.2019.01.060 210 THƯ VIỆN TRƯỜNG ĐẠI HỌC BÁCH KHOA – ĐẠI HỌC ĐÀ NẴNG Lưu hành nội [2] S.Yang, C Chen, L Liu, L Zhu, X Xu, Mater Res Bull 2017, 92, 29– 38 DOI: 10.1016/j.materresbull.2017.03.055 [3] Y Dong, C Feng, J Zhang, P Jiang, G Wang, X Wu, H Miao, Chem Asian J 2014, 00, – DOI: 10.1002/asia.201403217 [4] Y Li, Z Zhang, Y Zhang, X Sun, J Zhang, C Wang, Z Peng, H Si, Ceram Int 2014, 40, 13275–13280 DOI: 10.1016/j.ceramint.2014.05.037 Table A1.1 C 1s binding energies and their relative area percentages from the deconvoluted XPS spectrum of ZnO/RGO (sZG) and GO ZnO/RGO (sZG) Bonds C–C/ C=C C–O O–C=O GO C–C/ - * C=C C–O Binding 284.5 285.4 288.3 290.3 284.4 285.3 energy (eV) Relative 31.2 52.5 8.1 8.2 10.2 29.4 area (%) a This appears at the same wavelength as C=O O–C=O O–C–Oa 288.7 287.2 12.0 48.4 Table A3.1 Composition of CMST obtained from ICP and TGA Catalysts %TiO2 (from ICP) %MoS2 (from ICP) Carbon (from TGA) CMST 84.6% 10.7% 4.7% Table A3.2 Comparison of the photocatalytic activities (degradation efficiency and reaction rate constant) of five different catalysts with a catalyst loading of 0.2 g L‒1 and concentration dye (MB): 10 mg L‒1 using 150 W solar simulator 211 THƯ VIỆN TRƯỜNG ĐẠI HỌC BÁCH KHOA – ĐẠI HỌC ĐÀ NẴNG Lưu hành nội Degradation efficiency [%] Apparent rate constant [k, min‒1] Regression coefficients R2 P25 90 0.037 0.997 Spindle TiO2 40 0.008 0.994 CMS 20 0.002 0.980 MST 17 0.0015 0.949 CMST 99 0.067 0.989 Catalysts Table A6.1 Photocatalytic activity of the Ag/AgBr@BiOBr/Bi2O3 catalyst (catlyst loading of 0.3 g L‒1, RhB concentration of 10 mg L‒1, degradation time of 60 min, visible light) Degradation Regression Apparent rate Temperature efficiency constant coefficients [%] [°C] [k, min‒1] R2 25 0.073 91.4 0.99 35 0.116 95.0 0.99 45 0.146 99.3 0.97 태양광 하에서 효과적인 오염물질 분해를 위한 Zscheme 혼성접점을 가지는 Type II 광촉매 개발 웬 반 쿠앙 212 THƯ VIỆN TRƯỜNG ĐẠI HỌC BÁCH KHOA – ĐẠI HỌC ĐÀ NẴNG Lưu hành nội 영남대학교 대학원 화학공학과 화학공학전공 (지도교수: 심재진 교수) 요 약 최근 Z-scheme 광촉매시스템은 환경개선에의 응용을 위한 광촉매 설계에서 더 많은 관심을 끌고 있다 기존의 광촉매 설계와 비교할 때 Z-scheme 에 기반한 설계는 광촉매활성 및 촉매의 안정성을 향상시키는 이상적인 해법으로 선택되었다 이 Z-scheme 광촉매 시스템은 광유도전자와 정공의 재결합을 감소시킬뿐만 아니라 탁월한 산화환원 능력을 가지고 있다 이 논문은 ZnO/그래핀의 단순한 구조에서 반도체 (TiO2, C-MoS2, BiPO4, BiOCl, Ag/AgBr, BiOBr, Bi2O3) 사이의 Z-scheme 기반 구조에 이르기까지 다양한 광촉매 시스템에 대해서 다루었다 각 광촉매 시스템에 대해 메틸렌블루(MB), 로다민 B(RhB), 메틸오렌지 (MO), 테트라사이클린 하이드로 클로라이드 (TCH), 하이드록시 클로로퀸 (HCQ)과 같은 유기 오염물질의 분해에서 광촉매 합성방법, 특성화, 광촉매 활성, 광촉매시스템의 오염물질 분해메커니즘에 대해서 논의하였다 장에서는 단계 방법으로 합성된 나노 구형 ZnO/rGO 복합재가 높은 MB 및 RhB 제거효율과 자외선 하에서 우수한 안정성을 가짐을 보여주었다 213 THƯ VIỆN TRƯỜNG ĐẠI HỌC BÁCH KHOA – ĐẠI HỌC ĐÀ NẴNG Lưu hành nội 장에서는 C-MoS2/TiO2 나노복합체의 Z-scheme 이종 접합 광촉매를 단계 수열합성법 (고온 및 고압)으로 제조했다 Z-scheme 광촉매는 태양광 하에서 MB, RhB, TCH 의 분해에서 광촉매활성이 개선됨을 보여주었다 장에서는 BiOBr/Bi2O3 나노 종이에서 누에고치 같은 BiPO4 의 Z-scheme 삼원광촉매를 합성하기 위해 간편하고 빠른 마이크로파 보조 단일단계 합성방법이 사용되었다 세 가지 비스무트 기반 구성 요소들 사이의 Z-scheme 전하전달메커니즘은 태양광 아래에서 RhB 열화를 촉진시켰다 또한 광촉매는 태양광 아래에서 TCH, HCQ 및 MO 공해물질에 대해 우수한 광촉매활성을 보여주었다 장에서는 장에서와 같은 합성방법에 따라 층구조 BiOCl/BiOBr/Bi2O3 나노복합체의 Z-scheme 삼원광촉매를 제조하였으며, 가시광선과 태양광 하에서 고농도의 RhB 염료 분해에서 우수한 광촉매활성과 안정성을 가짐을 입증했다 이 Zscheme 광촉매는 TCH 및 MO 오염물질에 대해서도 우수한 광촉매 활성을 나타냈다 장에서는 장과 장에서 설명한 것과 동일한 방법을 사용하여 Ag/AgBr@BiOBr/Bi2O3 나노복합체의 Z-scheme 사원광촉매를 합성하였다 이 사원광촉매는 가시광선 하에서 MO 염료분해에 높은 제거효율과 탁월한 안정성을 보여주었다 이 광촉매는 또한 발광 다이오드 (LED), 할로겐 램프 (오버헤드 프로젝터) 및 인공 태양광 등 다양한 광원 하에서 RhB 및 TCH 에 대해 우수한 광촉매 활성을 나타 냈다 214 THƯ VIỆN TRƯỜNG ĐẠI HỌC BÁCH KHOA – ĐẠI HỌC ĐÀ NẴNG Lưu hành nội 마이크로웨이브 보조 단일단계 합성법은 비교적 낮은 온도에서 빠르고 제어가능하게 촉매를 합성할 수 있으므로 Z-scheme 광촉매를 대규모로 합성하기 위한 공정으로서 선호될 수 있다 215 THƯ VIỆN TRƯỜNG ĐẠI HỌC BÁCH KHOA – ĐẠI HỌC ĐÀ NẴNG Lưu hành nội ...Ph.D Thesis Development of Z-scheme heterojunction Type II photocatalysts for efficient degradation of pollutants under solar light irradiation Advisor: Prof Jae-Jin Shim Presented... method and their use as photocatalysts for the degradation of MB and RhB dyes under UV light and solar light irradiation Chapter presents the synthesis of Z-scheme photocatalyst of CMoS2/TiO2 octahedra... activity of the photocatalyst under solar or visible illumination such as semiconductor/carbon materials (graphene) [11], semiconductor/ semiconductor heterojunction (type I, type II, and type III heterojunction)