华中科技大学谭必恩团队报道了通过由熔融构建块构建的共价三嗪框架实现前所未有的光催化过氧化氢生产。相关研究成果发表在2024年9月9日出版的《德国应用化学》。

共价有机框架（COFs）因其在光催化过氧化氢（H₂O₂）生产中的潜力而受到关注。然而，它们的光催化效率受到激子解离和载流子输运不足的阻碍。构建具有优良平面度的COFs是提高π共轭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，破坏共面性。

该文中，研究人员通过引入固有共面的三嗪环作为连接体和熔融构建块作为单体来解决这个问题，以创建具有优异共面性的共价三嗪框架（熔融CTFs）。实验和理论计算都证实，与用非熔融构建块构建的CTFs相比，由熔融构建块构造的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，ORR优先由三嗪环促进，WOR可能发生在含噻吩的部分。值得注意的是，CTF-BTT在O₂饱和气氛中使用10%苯甲醇（V/V）作为牺牲剂时，实现了74956μmol g^-1 h^-1的H₂O₂生产率，比现有的光催化剂高出近一个数量级。

附：英文原文

Title: Unprecedented Photocatalytic Hydrogen Peroxide Production via Covalent Triazine Frameworks Constructed from Fused Building Blocks

Author: Ruixue Sun, Xiaoju Yang, Xunliang Hu, Yatong Guo, Yaqing Zhang, Chang Shu, Xuan Yang, Hui Gao, Xiaoyan Wang, Irshad Hussain, Bien Tan

Issue&Volume: 2024-09-09

Abstract: Covalent organic frameworks (COFs) have garnered attention for their potential in photocatalytic hydrogen peroxide (H2O2) 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 (fused 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 ORR is preferentially facilitated by the triazine rings, with the WOR likely occurring at the thiophene-containing moiety. Remarkably, CTF-BTT achieved an exceptional H2O2 production rate of 74956 μmol g1 h1 when employing 10% benzyl alcohol (V/V) as a sacrificial agent in an O2-saturated atmosphere, surpassing existing photocatalysts by nearly an order of magnitude.

DOI: 10.1002/anie.202416350

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202416350