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 THƯ VIỆN TRƯỜNG ĐẠI HỌC BÁCH KHOA – ĐẠI HỌC ĐÀ NẴNG Lưu hành nội 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 THƯ VIỆN TRƯỜNG ĐẠI HỌC BÁCH KHOA – ĐẠI HỌC ĐÀ NẴNG Lưu hành nội 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 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 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 ii 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 THƯ VIỆN TRƯỜNG ĐẠI HỌC BÁCH KHOA – ĐẠI HỌC ĐÀ NẴNG Lưu hành nội 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 THƯ VIỆN TRƯỜNG ĐẠI HỌC BÁCH KHOA – ĐẠI HỌC ĐÀ NẴNG Lưu hành nội 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 v THƯ VIỆN TRƯỜNG ĐẠI HỌC BÁCH KHOA – ĐẠI HỌC ĐÀ NẴNG Lưu hành nội .. .Development of Z-scheme heterojunction Type II photocatalysts for efficient degradation of pollutants under solar light irradiation Advisor: Prof Jae-Jin Shim Presented... 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... 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