Tuning the exciton binding energy of covalent organic frameworks for efficient photocatalysis  

作　　者：Zhangjie Gu Zhen Shan Yulan Wang Jinjian Wang Tongtong Liu Xiaoming Li Zhiyang Yu Jian Su Gen Zhang 

机构地区：[1]Key Laboratory for Soft Chemistry and Functional Materials of Ministry of Education,School of Chemistry and Chemical Engineering,Nanjing University of Science and Technology,Nanjing 210094,China [2]State Key Laboratory of Photocatalysis on Energy and Environment,College of Chemistry,Fuzhou University,Fuzhou 350002,China [3]MIIT Key Laboratory of Advanced Display Material and Devices,School of Materials Science and Engineering,Nanjing University of Science and Technology,Nanjing 210094,China [4]Key Laboratory of Preclinical Study for New Drugs of Gansu Province,School of Basic Medical Sciences,Lanzhou University,Lanzhou 730000,China

出　　处：《Chinese Chemical Letters》2024年第2期577-583,共7页中国化学快报（英文版）

基　　金：financially supported by the National Natural Science Foundation of China(No.22171136);the Natural Science Foundation of Jiangsu Province(Nos.BK20220928,BK20220079);the Fundamental Research Funds for the Central Universities(Nos.30921011102,30922010902);the Medical Innovation and Development Project of Lanzhou University(No.lzuyxcx-2022-156);CAMS Innovation Fund for Medical Sciences(CIFMS,Nos.2019-I2M-5-074,2021-I2M-1-026,2021-I2M-3-001);the Startup Funding from Nanjing University of Science and Technology(Nos.AE89990,AE89991/376);G.Zhang acknowledges the support of the Thousand Young Talent Plan.

摘　　要：Owing to the large exciton binding energy(>100 meV)of most organic materials,the process of exciton dissociation into free electrons and holes is seriously hindered,which plays a key role in the photocatalytic system.In this study,a series of chalcogen(S,Se)-substituted mesoporous covalent organic frameworks(COFs)have been synthesized for enhanced photocatalytic organic transformations.Photoelectrochemical measurements indicate that the introduction of semi-metallic Se atom and the enlargement of conjugation degree can not only reduce the exciton binding energy accelerating the charge separation,but also reduce the band gap of COFs.As a result,the COF-NUST-36 with the lowest exciton binding energy(39.5 meV)shows the highest photocatalytic performance for selective oxidation of amines(up to 98%Conv.and 97.5%Sel.).This work provides a feasible method for designing COFs with high photocatalytic activity by adjusting exciton binding energy.

关 键 词：Covalent organic frameworks Exciton binding energy Atom substitution Extended conjugation PHOTOCATALYSIS 

分 类 号：O643.36[理学—物理化学] O644.1[理学—化学]