Covalent Organic Frameworks Containing Dual O2 Reduction Centers for Overall Photosynthetic Hydrogen Peroxide Production

• Published in: Angewandte Chemie International Edition Vol. 62; no. 9; pp. e202217479 - n/a
• Main Authors: Chen, Dan, Chen, Weiben, Wu, Yuting, Wang, Lei, Wu, Xiaojun, Xu, Hangxun, Chen, Long
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 20-02-2023
• Edition: International ed. in English
• Subjects: Catalytic Sites; Charge Transfer; Chemical energy; Covalent Organic Frameworks; Energy efficiency; Hydrogen Peroxide; Photocatalysis; Photosynthesis; Quantum efficiency; Reduction; Solar energy; Triazine
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.202217479

Covalent organic frameworks (COFs) are highly desirable for achieving high‐efficiency overall photosynthesis of hydrogen peroxide (H2O2) via molecular design. However, precise construction of COFs toward overall photosynthetic H2O2 remains a great challenge. Herein, we report the crystalline s‐heptazine‐based COFs (HEP‐TAPT‐COF and HEP‐TAPB‐COF) with separated redox centers for efficient H2O2 production from O2 and pure water. The spatially and orderly separated active sites in HEP‐COFs can efficiently promote charge separation and enhance photocatalytic H2O2 production. Compared with HEP‐TAPB‐COF, HEP‐TAPT‐COF exhibits higher H2O2 production efficiency for integrating dual O2 reduction active centers of s‐heptazine and triazine moieties. Accordingly, HEP‐TAPT‐COF bearing dual O2 reduction centers exhibits a remarkable solar‐to‐chemical energy efficiency of 0.65 % with a high apparent quantum efficiency of 15.35 % at 420 nm, surpassing previously reported COF‐based photocatalysts.
Two crystalline heptazine‐based covalent organic frameworks (HEP‐COFs) with spatially separated redox centers are designed for efficient visible‐light‐driven H2O2 production from O2 and water without using any sacrificial agents. HEP‐COFs with dual O2 reduction centers aid charge separation to give improved photocatalytic performance. The rational design of metal‐free polymeric photocatalysts boosts the efficiency of artificial photosynthesis.