Rational Design of Vinylene‐Linked Covalent Organic Frameworks for Modulating Photocatalytic H<sub>2</sub> Evolution
Na Qin, Aojie Mao, Linqiang Li, Chao Lin, Lipeng Zhai, Jing Liu, Junhua Zou, Cheng‐Xing Cui, Liwei Mi
Abstract
Abstract Vinylene‐linked covalent organic frameworks (COFs) have attracted enormous attention for photocatalytic H 2 evolution from water because of their fully conjugated structures, high chemical stabilities, and enhanced charge‐carrier mobilities. In this work, two novel vinylene‐linked COFs with tuned cyano contents were successfully synthesized and then employed as photocatalysts for H 2 generation. Notably, the photocatalytic H 2 production rate of the COF with the higher cyano content reached 73 μmol h −1 under visible light irradiation, which is 2.4 times higher than that with the lower content (30 μmol h −1 ). Both the experimental and computational results demonstrated that the rational design incorporating cyano groups into COF skeletons could precisely tune the corresponding energy levels, expand the visible‐light absorption, and improve the photoinduced charge separation. This work not only provides a simple method for modulating the photocatalytic activities of COFs at the molecular level, but also affords interesting insights into the relationship between their structures and photocatalytic performance.