Sun Ruixue, Yang Xiaoju, Hu Xunliang, Guo Yantong, Zhang Yaqin, Shu Chang, Yang Xuan, Gao Hui, Wang Xiaoyan, Hussain Irshad, Tan Bien
Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education, Hubei Key Laboratory of Material Chemistry and Service Failure, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Luoyu Road No. 1037, 430074, Wuhan, P. R. China.
Department of Chemistry and Chemical Engineering, SBA School of Science and Engineering (SSE), Lahore University of Management Sciences (LUMS), 54792, Lahore Cantt, Pakistan.
Angew Chem Int Ed Engl. 2025 Jan 21;64(4):e202416350. doi: 10.1002/anie.202416350. Epub 2024 Oct 30.
Covalent organic frameworks (COFs) have garnered attention for their potential in photocatalytic hydrogen peroxide (HO) production. However, their photocatalytic efficiency is impeded by insufficient exciton dissociation and charge carrier transport. Constructing COFs with superior planarity is an effective way to enhance the π-conjugation degree and facilitate electron-hole separation. Nonetheless, the conventional linear linkers of COFs inevitably introduce torsional strain that disrupts coplanarity. Herein, we address this issue by introducing inherently coplanar triazine rings as linkers and fused building blocks as monomers to create covalent triazine frameworks (CTFs) with superior coplanarity. Both experimental and theoretical calculations confirm that CTFs constructed from fused building blocks significantly enhance the electron-hole separation efficiency and improve the photocatalytic performance, compared to the CTFs constructed with non-fused building blocks. The frontier molecular orbitals and electrostatic potentials (ESP) revealed that the oxygen reduction reaction (ORR) is preferentially facilitated by the triazine rings, with the water oxidation reaction (WOR) likely occurring at the thiophene-containing moiety. Remarkably, CTF-BTT achieved an exceptional HO production rate of 74956 μmol g h when employing 10 % benzyl alcohol (V/V) as a sacrificial agent in an O-saturated atmosphere, surpassing existing photocatalysts by nearly an order of magnitude. Our findings provide valuable insights for designing highly coplanar polymer-based photocatalysts that enhance the solar-to-chemical energy conversion process.
共价有机框架（COFs）因其在光催化生产过氧化氢（HO）方面的潜力而受到关注。然而，其光催化效率受到激子解离不足和电荷载流子传输的阻碍。构建具有优异平面性的COFs是提高π共轭程度和促进电子-空穴分离的有效方法。尽管如此，COFs的传统线性连接体不可避免地会引入扭转应变，从而破坏共平面性。在此，我们通过引入固有共平面的三嗪环作为连接体和稠合结构单元作为单体来解决这一问题，以创建具有优异共平面性的共价三嗪框架（CTFs）。实验和理论计算均证实，与由非稠合结构单元构建的CTFs相比，由稠合结构单元构建的CTFs显著提高了电子-空穴分离效率并改善了光催化性能。前沿分子轨道和静电势（ESP）表明，三嗪环优先促进氧还原反应（ORR），而水氧化反应（WOR）可能发生在含噻吩部分。值得注意的是，当在O2饱和气氛中使用10%（V/V）的苯甲醇作为牺牲剂时，CTF-BTT实现了74956 μmol g-1 h-1的优异HO生成速率，比现有光催化剂高出近一个数量级。我们的研究结果为设计增强太阳能到化学能转换过程的高度共平面聚合物基光催化剂提供了有价值的见解。
