Metal–organic frameworks (MOFs) as photocatalysts and photocatalyst supports combine several advantages of homogeneous and heterogeneous catalyses, including stability, post-reaction separation, catalyst reusability,...Metal–organic frameworks (MOFs) as photocatalysts and photocatalyst supports combine several advantages of homogeneous and heterogeneous catalyses, including stability, post-reaction separation, catalyst reusability,and tunability, and they have been intensively studied for photocatalytic applications. There are several reviews that focus mainly or even entirely on experimental work. The present review is intended to complement those reviews by focusing on computational work that can provide a further understanding of the photocatalytic properties of MOF photocatalysts. We first present a summary of computational methods, including density functional theory, combined quantum mechanical and molecular mechanical methods, and force fields for MOFs. Then, computational investigations on MOF-based photocatalysis are briefly discussed. The discussions focus on the electronic structure, photoexcitation, charge mobility, and photoredox catalysis of MOFs, especially the widely studied Ui O-66-based MOFs.展开更多
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 fu...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.展开更多
基金supported as part of the Nanoporous Materials Genome Center by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences, under Award No. DE-FG0217ER16362
文摘Metal–organic frameworks (MOFs) as photocatalysts and photocatalyst supports combine several advantages of homogeneous and heterogeneous catalyses, including stability, post-reaction separation, catalyst reusability,and tunability, and they have been intensively studied for photocatalytic applications. There are several reviews that focus mainly or even entirely on experimental work. The present review is intended to complement those reviews by focusing on computational work that can provide a further understanding of the photocatalytic properties of MOF photocatalysts. We first present a summary of computational methods, including density functional theory, combined quantum mechanical and molecular mechanical methods, and force fields for MOFs. Then, computational investigations on MOF-based photocatalysis are briefly discussed. The discussions focus on the electronic structure, photoexcitation, charge mobility, and photoredox catalysis of MOFs, especially the widely studied Ui O-66-based MOFs.
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)+2 种基金Shanghai Sailing Program(No.20YF1410000)Shanghai Municipal Science and Technology Major Project(No.2018SHZDZX03)Shanghai Science and Technology Committee(No.17520750100).
文摘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.
