Key Laboratory for Advanced Materials and Joint International Research Laboratory for Precision Chemistry and Molecular Engineering, School of Chemistry and Molecular Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, China.
Key Laboratory for Advanced Materials and Joint International Research Laboratory for Precision Chemistry and Molecular Engineering, School of Chemistry and Molecular Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, China; State Key Laboratory of Chemical Engineering and Department of Chemistry, East China University of Science and Technology, Shanghai, 200237, China.
Chemosphere. 2024 May;356:141947. doi: 10.1016/j.chemosphere.2024.141947. Epub 2024 Apr 8.
Covalent organic frameworks (COFs) have recently emerged as a kind of promising photocatalytic platform in addressing the growing threat of trace pollutants in aquatic environments. Along this, we propose a strategy of constructing internal electric field (IEF) in COFs through the dipole moment regulation, which intrinsically facilitates the separation and transfer of photogenerated excitons. Two COFs of BTT-TZ-COF and BTT-TB-COF are developed by linking the electron-donor of benzotrithiophene (BTT) block and the electron-acceptor of triazine (TZ) or tribenzene (TB) block, respectively. DFT calculations demonstrate TZ block with larger dipole moment can achieve more efficient IEF due to the stronger electron-attractive force and hence narrower bandgap. Moreover, featuring the highly-order crystalline structure for accelerating photo-excitons transfer and rich porosity for facilitating the adsorption, BTT-TZ-COF exhibited an excellent universal performance of photocatalytic degradations of various dyes. Specifically, a superior photodegradation efficiency of 99% Rhodamine B (RhB) is achieved within 20 min under the simulated sunlight. Therefore, this convenient construction approach of enhanced IEF in COFs through rational regulation of the dipole moment can be a promising way to realize high photocatalytic activity.
共价有机框架（COFs）作为一种有前途的光催化平台，近年来在解决水生环境中痕量污染物日益增长的威胁方面崭露头角。在此基础上，我们提出了一种通过偶极矩调节在 COFs 中构建内电场（IEF）的策略，这从本质上促进了光生激子的分离和转移。通过连接电子给体苯并三噻吩（BTT）和电子受体三嗪（TZ）或三联苯（TB），分别合成了两种 COFs：BTT-TZ-COF 和 BTT-TB-COF。DFT 计算表明，由于更强的电子吸引力，具有更大偶极矩的 TZ 部分可以实现更有效的 IEF，从而导致更窄的带隙。此外，BTT-TZ-COF 具有高度有序的结晶结构，可加速光生激子的转移，丰富的孔隙率可促进吸附，因此对各种染料的光催化降解表现出优异的通用性能。具体而言，在模拟阳光下，BTT-TZ-COF 在 20 分钟内实现了 99%的 Rhodamine B（RhB）的高效光降解。因此，通过合理调节偶极矩来增强 COFs 中的内电场的这种简便构建方法，可能是实现高光催化活性的一种有前途的途径。
