2065232-74-6Relevant articles and documents
Embedding Ultrasmall Au Clusters into the Pores of a Covalent Organic Framework for Enhanced Photostability and Photocatalytic Performance
Deng, Yang,Du, Peiyao,Liu, Jia,Lu, Xiaoquan,Ning, Xingming,Wang, Yue,Zhang, Dongxu,Zhang, Shouting,Zhang, Zhen
, p. 6082 - 6089 (2020)
Gold clusters loaded on various supports have been widely used in the fields of energy and biology. However, the poor photostability of Au clusters on support interfaces under prolonged illumination usually results in loss of catalytic performance. Covalent organic frameworks (COFs) with periodic and ultrasmall pore structures are ideal supports for dispersing and stabilizing Au clusters, although it is difficult to encapsulate Au clusters in the ultrasmall pores. In this study, a two-dimensional (2D) COF modified with thiol chains in its pores was prepared. With ?SH groups as nucleation sites, Au nanoclusters (NCs) could grow in situ within the COF. The ultrasmall pores of the COF and the strong S?Au binding energy combine to improve the dispersibility of Au NCs under prolonged light illumination. Interestingly, Au–S–COF bridging as observed in this artificial Z-scheme photocatalytic system is deemed to be an ideal means to increase charge-separation efficiency.
Confining perovskite quantum dots in the pores of a covalent-organic framework: quantum confinement- And passivation-enhanced light-harvesting and photocatalysis
Hai, Jun,Liu, Qiang,Meng, Genping,Sun, Dina,Sun, Shihao,Wang, Baodui,Zhang, Zefan,Zhen, Liping
, p. 24365 - 24373 (2021/11/17)
All-inorganic lead halide perovskites have attracted significant attention in artificial light-harvesting systems (ALHSs) due to their superior emission tunability and high light-absorption coefficients. However, their relatively low photoluminescence quantum yield (PLQY), surface defects, and poor thermal and air stability severely hinder their actual applications. Here, we demonstrate a simple and versatile method to grow monodisperse CsPbX3(X = Cl, Br, I) perovskite quantum dots (QDs) into the ordered mesopores of a thiol-functionalized covalent-organic framework (COF-SH) as emission-tunable antennas. Intriguingly, benefiting from the quantum confinement and defect-passivation, the resulting CsPbX3@COF-SH not only presents dramatically improved environmental and thermal stability, but also exhibits enhanced PLQY (30.2%), significantly higher than that of pristine CsPbX3perovskite bulk crystals (less than 1.0%). Importantly, the emission spectra of antennas could be precisely tuned by tailoring the halogen component to achieve the well-matched intersections between the emission peak of the antennas and the absorption peak of eosin Y (ESY) or rose bengal (RB) acceptor in ALHSs. As a result, the efficiency of energy transfer achieved from CsPbBr3@COF-SH to ESY and from CsPbBr2I@COF-SH to RB reached up to 94.4% and 93.6%, respectively. To better imitate natural photosynthesis, ESY-CsPbBr3@COF-SH and RB-CsPbBr2I@COF-SH systems were employed as photochemical catalysts for C-H selenation and cross-coupling/annulation reactions, respectively, and both systems showed elevated catalytic activity with excellent yields of up to 99.3% and 95.5% and far surpassing that of ESY or RB alone. This work clearly demonstrates the great advantages of COFs in the fabrication of embedded perovskite QDs with enhanced photoluminescence, thereby facilitating light-harvesting and promoting light-converting applications.
Pore Environment Control and Enhanced Performance of Enzymes Infiltrated in Covalent Organic Frameworks
Sun, Qi,Fu, Chung-Wei,Aguila, Briana,Perman, Jason,Wang, Sai,Huang, Hsi-Ya,Xiao, Feng-Shou,Ma, Shengqian
, p. 984 - 992 (2018/02/07)
In the drive toward green and sustainable methodologies for chemicals manufacturing, biocatalysts are predicted to have much to offer in the years to come. That being said, their practical applications are often hampered by a lack of long-term operational stability, limited operating range, and a low recyclability for the enzymes utilized. Herein, we show how covalent organic frameworks (COFs) possess all the necessary requirements needed to serve as ideal host materials for enzymes. The resultant biocomposites of this study have shown the ability boost the stability and robustness of the enzyme in question, namely lipase PS, while also displaying activities far outperforming the free enzyme and biocomposites made from other types of porous materials, such as mesoporous silica and metal-organic frameworks, exemplified in the kinetic resolution of the alcohol assays performed. The ability to easily tune the pore environment of a COF using monomers bearing specific functional groups can improve its compatibility with a given enzyme. As a result, the orientation of the enzyme active site can be modulated through designed interactions between both components, thus improving the enzymatic activity of the biocomposites. Moreover, in comparison with their amorphous analogues, the well-defined COF pore channels not only make the accommodated enzymes more accessible to the reagents but also serve as stronger shields to safeguard the enzymes from deactivation, as evidenced by superior activities and tolerance to harsh environments. The amenability of COFs, along with our increasing understanding of the design rules for stabilizing enzymes in an accessible fashion, gives great promise for providing "off the shelf" biocatalysts for synthetic transformations.
Postsynthetically Modified Covalent Organic Frameworks for Efficient and Effective Mercury Removal
Sun, Qi,Aguila, Briana,Perman, Jason,Earl, Lyndsey D.,Abney, Carter W.,Cheng, Yuchuan,Wei, Hao,Nguyen, Nicholas,Wojtas, Lukasz,Ma, Shengqian
, p. 2786 - 2793 (2017/03/01)
A key challenge in environmental remediation is the design of adsorbents bearing an abundance of accessible chelating sites with high affinity, to achieve both rapid uptake and high capacity for the contaminants. Herein, we demonstrate how two-dimensional covalent organic frameworks (COFs) with well-defined mesopore structures display the right combination of properties to serve as a scaffold for decorating coordination sites to create ideal adsorbents. The proof-of-concept design is illustrated by modifying sulfur derivatives on a newly designed vinyl-functionalized mesoporous COF (COF-V) via thiol-ene "click" reaction. Representatively, the material (COF-S-SH) synthesized by treating COF-V with 1,2-ethanedithiol exhibits high efficiency in removing mercury from aqueous solutions and the air, affording Hg2+ and Hg0 capacities of 1350 and 863 mg g-1, respectively, surpassing all those of thiol and thioether functionalized materials reported thus far. More significantly, COF-S-SH demonstrates an ultrahigh distribution coefficient value (Kd) of 2.3 × 109 mL g-1, which allows it to rapidly reduce the Hg2+ concentration from 5 ppm to less than 0.1 ppb, well below the acceptable limit in drinking water (2 ppb). We attribute the impressive performance to the synergistic effects arising from densely populated chelating groups with a strong binding ability within ordered mesopores that allow rapid diffusion of mercury species throughout the material. X-ray absorption fine structure (XAFS) spectroscopic studies revealed that each Hg is bound exclusively by two S via intramolecular cooperativity in COF-S-SH, further interpreting its excellent affinity. The results presented here thus reveal the exceptional potential of COFs for high-performance environmental remediation.
