Enaminone‐Linked Covalent Organic Frameworks for Boosting Photocatalytic Hydrogen Production

Abstract 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.