Impact of Imine Bond Orientations and Acceptor Groups on Photocatalytic Hydrogen Generation of Donor-Acceptor Covalent Organic Frameworks

• Published in: Small (Weinheim an der Bergstrasse, Germany) p. e2405887
• Main Authors: Han, Chao-Qin, Guo, Jia-Xin, Sun, Shuai, Wang, Ze-Yang, Wang, Lei, Liu, Xiao-Yuan
• Format: Journal Article
• Language: English
• Published: Germany 09.09.2024
• Subjects: imine bond orientation; covalent organic frameworks; donor‐acceptor; hydrogen generation
• ISSN: 1613-6810; 1613-6829; 1613-6829
• DOI: 10.1002/smll.202405887

Covalent organic frameworks (COFs) have emerged as one of the most studied photocatalysts owing to their adjustable structure and bandgaps. However, there is limited research on regulating the light-harvesting capabilities of acceptor building blocks in donor-acceptor (D-A) isomer COFs with different bond orientations. This investigation is crucial for elucidating the structure-property-performance relationship of COF photocatalysts. Herein, a series of D-A isostructural COFs are synthesized with different imine bond orientations using benzothiadiazole and its derivatives-based organic building units. Extended light absorption is achieved in COFs with acceptor groups that have strong electron-withdrawing capacities, although this resulted a decreased hydrogen generation efficiency. Photocatalytic experiments indicated that dialdehyde benzothiadiazole-based COFs, HIAM-0015, exhibit the highest hydrogen generation rate (17.99 mmol g h ), which is 15 times higher than its isomer. The excellent photocatalytic performance of HIAM-0015 can be attributed to its fast charge separation and migration. This work provides insights into the rational design and synthesis of D-A COFs to achieve efficient photocatalytic activity.