Modulating N‐Heterocyclic Microenvironment in β ‐Ketoenamine Covalent Organic Frameworks to Boost Overall Photosynthesis of H 2 O 2

作者：Yangpeng Zhang, Youting Wu, Hailing Ma, Yue Gao, Xiaoli Fan, Yuehan Zhao, Fangyuan Kang, Zhonghua Li, Yang Liu, Qichun Zhang · 发表于：Small · 年份：2025 · DOI：10.1002/smll.202500674 · 被引用次数：52 · 研究领域：Covalent Organic Framework Applications、Metal-Organic Frameworks: Synthesis and Applications、Advanced Photocatalysis Techniques

Abstract Covalent Organic Frameworks (COFs) have emerged as promising platforms for photocatalytic synthesis of hydrogen peroxide (H 2 O 2 ) due to their tunable chemical compositions and efficient catalytic functionalities. Inspired by the role of the microenvironment in enzyme catalysis, this study introduces various N‐heterocyclic species into β ‐ketoenamine COFs (N x ‐COFs, where N x represents the number of nitrogen atoms in the N‐heterocycle) to regulate the microenvironment around catalytic sites on acceptor‐donor‐acceptor (A‐D‐A) COFs foroverall H 2 O 2 photosynthesis in pure water. The N x ‐COFs exhibit distinct H 2 O 2 photosynthetic rates following the number of nitrogen atoms sequence of N 3 ‐COF > N 2 ‐COF > N 1 ‐COF > N 0 ‐COF, with N 3 ‐COF with triazine structure showing the highest H 2 O 2 generation rate (4881 µmol h −1 g −1 ) and the decent solar‐to‐chemical conversion (SCC) efficiency (0.413%), surpassing many existing COF‐based catalysts. In situ characterization and theoretical calculations support the experimental results, revealing that N‐heterocyclic species promote the photosynthesis of H 2 O 2 through both an indirect stepwise single‐electron oxygen reduction reaction (1e − ORR) mechanism and a direct two‐electron water oxidation (2e − WOR) pathway. This study advances the design paradigm of photocatalysts by modulating the microenvironment within A‐D‐A COFs, paving the way for the development of more efficient and robust photocatalytic sys...