Regulating the Photoisomerization of Covalent Organic Framework for Enhanced Photocatalytic Hydrogen Evolution  

作　　者：Xingye Huang Jia Guo 

机构地区：[1]State Key Laboratory of Molecular Engineering of Polymers,Department of Macromolecular Science,Fudan University,Shanghai,200438 China

出　　处：《Chinese Journal of Chemistry》2024年第21期2621-2626,共6页中国化学（英文版）

基　　金：financially supported by the NSFC(Nos.52173197 and 52373202).

摘　　要：Covalent organic framework(COF)is a desirable platform to tailor electronic properties for improving photocatalytic performances.However,the study on excited-state configurations that determine photogenerated carrier dynamics has long been neglected.Herein,we concentrate on the molecular design ofβ-ketoenamine-linked COFs to drive their photoisomerization via the excited-state intra-molecular proton transfer(ESIPT),which can induce the partial keto-to-enol tautomerization and accordingly rearrange the photoinduced charge distribution.We demonstrate that the push-pull electronic effect of functional side groups attached on the framework linkers is directly correlated with the ESIPT process.The phenylene linkers modified with electron-withdrawing cyano-groups reinforce the ESIPT-induced tautomerization,leading to the in situ partial enolization for extendedπ-conjugation and rearranged electron-hole distribution.In contrast,the electron-rich linkers limit the photoisomerization of COF and suppress the photoinduced electron accumulation.Thus,the maximum hydrogen evolution rate is achieved by the cyano-modified COF,reaching as high as 162.72 mmol·g^(-1)·h^(-1) with an apparent quantum efficiency of 13.44%at 475 nm,which is almost 11.5-fold higher than those of analogous COFs with electron-rich linkers.Our work opens up an avenue to control over the excited-state structure transformation for enhanced photochemical applications.

关 键 词：Covalent organic framework Hydrogen evolution reaction PHOTOISOMERIZATION PHOTOCATALYSIS Charge separation Water splitting 

分 类 号：O64[理学—物理化学]