Yang Xiubei, Pan Zi-Xian, Yue Jie-Yu, Li Xuewen, Liu Guojuan, Xu Qing, Zeng Gaofeng
CAS Key Laboratory of Low-Carbon Conversion Science and Engineering, Shanghai Advanced Research Institute (SARI), Chinese Academy of Sciences (CAS), Shanghai, 201210, P. R. China.
University of Chinese Academy of Sciences, Beijing, 100049, P. R. China.
Small. 2024 Nov;20(47):e2405907. doi: 10.1002/smll.202405907. Epub 2024 Aug 15.
Photocatalytic HO production is a green and sustainable route, but far from meeting the increasing demands of industrialization due to the rapid recombination of the photogenerated charge carriers and the sluggish reaction kinetics. Effective strategies for precisely regulating the photogenerated carrier behavior and catalytic activity to construct high-performance photocatalysts are urgently needed. Herein, a nitrogen-site engineering strategy, implying elaborately tuning the species and densities of nitrogen atoms, is applied for HO photogeneration performance regulation. Different nitrogen heterocycles, such as pyridine, pyrimidine, and triazine units, are polymerized with trithiophene units, and five covalent organic frameworks (COFs) with distinct nitrogen species and densities on the skeletons are obtained. Fascinatingly, they photocatalyzed HO production via dominated two-electron O reduction processes, including O-O -HO and O-O -O -HO dual pathways. Just in the air and pure water, the multicomponent TTA-TF-COF with the maximum nitrogen densities triazine nitrogen densities exhibited the highest HO production rate of 3343 µmol g h, higher than most of other reported COFs. The theoretical calculation revealed the higher activity is due to the easy formation of O and O in different catalytic process. This study gives a new insight into designing photocatalysis at atomic level.
光催化产生羟基自由基是一条绿色且可持续的途径，但由于光生载流子的快速复合和缓慢的反应动力学，远远不能满足工业化日益增长的需求。迫切需要有效的策略来精确调控光生载流子行为和催化活性，以构建高性能光催化剂。在此，一种氮位点工程策略，即精心调整氮原子的种类和密度，被应用于调控羟基自由基的光生成性能。不同的氮杂环，如吡啶、嘧啶和三嗪单元，与三噻吩单元聚合，得到了五种骨架上具有不同氮种类和密度的共价有机框架（COF）。令人着迷的是，它们通过主导的双电子氧还原过程光催化产生羟基自由基，包括O - O→HO和O - O→O→HO双途径。仅在空气和纯水中，具有最大氮密度（三嗪氮密度）的多组分TTA - TF - COF表现出最高的羟基自由基产生速率，为3343 μmol g⁻¹ h⁻¹，高于大多数其他报道的COF。理论计算表明，较高的活性是由于在不同催化过程中易于形成O₂⁻和O⁻。这项研究为在原子水平设计光催化提供了新见解。
