Guan Xinyu, Qian Yunyang, Zhang Xiyuan, Jiang Hai-Long
Hefei National Research Center for Physical Sciences at the Microscale, Department of Chemistry, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), University of Science and Technology of China, Hefei, Anhui, 230026, P.R. China.
Angew Chem Int Ed Engl. 2023 Aug 1;62(31):e202306135. doi: 10.1002/anie.202306135. Epub 2023 Jun 23.
Covalent organic frameworks (COFs), possessing pre-designable structures and tailorable functionalities, are promising candidates for photocatalysis. Nevertheless, the most studied imine-linked COFs (Im-COFs) usually suffer from unsatisfactory stability and photocatalytic performance. To meet this challenge, a series of highly stable enaminone-linked COFs (En-COFs) have been synthesized and afford much improved visible-light-driven hydrogen production activities, ranging from 44 to 1078 times that of isoreticular Im-COFs, with the only difference being the linkages (enaminone vs. imine) in their structures. The enhanced light-harvesting ability, facilitated exciton dissociation and improved chemical stability account for the superior activity. Furthermore, quinoline-linked COFs (Qu-COFs) have been further obtained via the post-modification of Im-COFs. Compared with Im-COFs, the photocatalytic activities of Qu-COFs are significantly improved after modification, but still below those of the corresponding En-COFs (3-107 times). The facile synthesis, excellent activity, and high chemical stability demonstrate that En-COFs are a promising platform for photocatalysis.
共价有机框架（COFs）具有可预先设计的结构和可定制的功能，是光催化领域颇具潜力的候选材料。然而，目前研究最多的亚胺连接的COFs（Im-COFs）通常稳定性和光催化性能不尽人意。为应对这一挑战，一系列高度稳定的烯胺酮连接的COFs（En-COFs）已被合成出来，并展现出显著提高的可见光驱动产氢活性，是同构Im-COFs的44至1078倍，两者结构上唯一的区别在于连接方式（烯胺酮与亚胺）。光捕获能力的增强、激子解离的促进以及化学稳定性的提高是其优异活性的原因。此外，通过Im-COFs的后修饰进一步获得了喹啉连接的COFs（Qu-COFs）。与Im-COFs相比，修饰后的Qu-COFs光催化活性显著提高，但仍低于相应的En-COFs（3至107倍）。其简便的合成方法、优异的活性和高化学稳定性表明En-COFs是一个很有前景的光催化平台。
