Substituent Effects on the Photocatalytic Properties of a Symmetric Covalent Organic Framework  

取代基效应对对称共价有机框架光催化性质的影响

作　　者：Ting-Ting Liu Xin-Ping Wu Xue-Qing Gong 刘婷婷;吴新平;龚学庆(华东理工大学化学与分子工程学院,上海200237)

机构地区：[1]Key Laboratory for Advanced Materials and Joint International Research Laboratory for Precision Chemistry and Molecular Engineering,Feringa Nobel Prize Scientist Joint Research Center,Centre for Computational Chemistry and Research Institute of Industrial Catalysis,School of Chemistry and Molecular Engineering,East China University of Science and Technology,Shanghai 200237,China

出　　处：《Chinese Journal of Chemical Physics》2022年第4期647-654,I0062-I0085,I0150,共33页化学物理学报（英文）

基　　金：This work was supported by the National Key R&D Program of China(No.2018YFA0208602);the National Natural Science Foundation of China(No.21825301 and No.22003016);Shanghai Sailing Program(No.20YF1410000);Shanghai Municipal Science and Technology Major Project(No.2018SHZDZX03);Shanghai Science and Technology Committee(No.17520750100).

摘　　要：Symmetric covalent organic framework(COF)photocatalysts generally suffer from inefficient charge separation and short-lived photoexcited states.By performing density functional theory(DFT)and time-dependent density functional theory(TDDFT)calculations,we find that partial substitution with one or two substituents(N or NH_(2))in the linkage of the representative symmetric COF(N_(0)-COF)gives rise to the separation of charge carriers in the resulting COFs(i.e.,N_(1)-COF,N_(2)-COF,(NH_(2))1-N_(0)-COF,and(NH_(2))2-N_(0)-COF).Moreover,we also find that the energy levels of the highest occupied crystal orbital(HOCO)and the lowest unoccupied crystal orbital(LUCO)of the N_(0)-COF can shift away from or toward the vacuum level,depending on the electron-withdrawing or electron-donating characters of the substituent.Therefore,we propose that partial substitution with carefully chosen electron-withdrawing or electron-donating substituents in the linkages of symmetric COFs can lead to efficient charge separation as well as appropriate HOCO and LUCO positions of the generated COFs for specific photocatalytic reactions.The proposed rule can be utilized to further boost the photocatalytic performance of many symmetric COFs.

关 键 词：Covalent organic framework PHOTOCATALYSIS Electronic structure Charge separation Density functional theory calculation 

分 类 号：O643.36[理学—物理化学] O644.1[理学—化学] O641.1