Custom‐Design of Strong Electron/Proton Extractor on COFs for Efficient Photocatalytic H2O2 Production

• Published in: Angewandte Chemie International Edition Vol. 63; no. 15; pp. e202320218 - n/a
• Main Authors: Li, Liyao, Lv, Ximeng, Xue, Yuanyuan, Shao, Huibo, Zheng, Gengfeng, Han, Qing
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 08.04.2024
• Edition: International ed. in English
• Subjects: covalent organic frameworks; Electric fields; Electron transfer; electron/proton extractor; Electrons; Extractors; Functional groups; Hydrogen peroxide; Irradiation; Light irradiation; oxygen functional groups; Photocatalysis; Photocatalysts; Photosynthesis; Protons; Sulfonic acid; Topology; Triazine; electron/proton extractor; oxygen functional groups; Photocatalysis; Covalent Organic Frameworks; hydrogen peroxide
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.202320218

The development of photocatalysts with continuous electron extraction and rapid proton transfer could kinetically accelerate the artificial photosynthesis, but remains a challenge. Herein, we report the topology‐guided synthesis of a high‐crystalline triazine covalent organic framework (COF) decorated by uniformly distributed polar oxygen functional groups (sulfonic group or carboxyl) as the strong electron/proton extractor for efficient photocatalytic H2O2 production. It was found that the polarity‐based proton transfer as well as electron enrichment in as‐obtained COFs played a crucial role in improving the H2O2 photosynthesis efficiency (i.e., with an activity order of sulfonic acid‐ (SO3H‐COF)>carboxyl‐ (COOH‐COF)>hydrogen‐ (H‐COF) functionalized COFs). The strong polar sulfonic acid group in the high‐crystalline SO3H‐COF triggered a well‐oriented built‐in electric field and more hydrophilic surface, which serves as an efficient carrier extractor enabling a continuous transportation of the photogenerated electrons and interfacial proton to the active sites (i.e., C atoms linked to −SO3H group). As‐accelerated proton‐coupled electron transfer (PCET), together with the stabilized O2 adsorption finally leads to the highest H2O2 production rate of 4971 μmol g−1 h−1 under visible light irradiation. Meanwhile, a quantum yield of 15 % at 400 nm is obtained, superior to most reported COF‐based photocatalysts. We custom‐designed a strong electron/proton extractor on COFs by introducing oxygen functional groups (−COOH and −SO3H) in high‐crystalline triazine‐containing COFs, which induces well‐oriented build‐in electron field and enhances the hydrophilicity, leading to fast proton‐coupled electron transfer process and enhanced O2 adsorption, and therefore boosted photocatalytic O2‐to‐H2O2 conversion.