Emerging porous nanosheets: From fundamental synthesis to promising applications

Abstract

Metal-organic framework (MOF) nanosheets and covalent organic framework (COF) nanosheets as emerging porous materials nanosheets have captured increasing attention owing to their attractive properties originating from the advantages of large lateral size, ultrathin thickness, tailorable physiochemical environment, flexibility and highly accessible active sites on surface, and the applications of them have been explored in a wide range of fields. Although MOF and COF nanosheets own many similar properties, their applications in various fields show significant differences, probably due to their different compositions and bonding modes. Hence, we summarize the recent progress of MOF and COF nanosheets by comparative analysis on their advantages and limitations in synthesis and applications, providing a more profound and full-scale perspective for researchers or beginners to understand this field. Herein, the categories of preparation methods of MOF and COF nanosheets are firstly discussed, including top-down and bottom-up methods. Secondly, the applications of MOF and COF nanosheets for separation, catalysis, sensing and energy storage are summarized. Finally, based on current achievements, we put forward our personal insights into the challenges and outlooks on the synthesis, characterizations, and promising applications for future research of MOF and COF nanosheets. KEYWORDS metal-organic framework (MOF) nanosheets, covalent organic framework (COF) nanosheets, top-down methods, bottom-up methods, two-dimensional (2D) nanomaterials

Two-dimensional metal-organic frameworks: from synthesis to bioapplications

“…Advancements in 2D MOFs for biomedical applications have occurred at a relatively slow pace compared with other 2D nanomaterials. With the diversity in the structural phases and the unique properties, the atomic-layered 2D MOFs have extraordinary advantages when exploited for various bioapplications [ 63 , 64 ]. This section focused on the bioapplications of 2D MOFs for biocatalysis and biosensor, biological imaging, and theranostics.…”

Chirality communications between inorganic and organic compounds

“…[15][16][17] More recently, chiral porous materials, such as metal-organic frameworks (MOFs), covalent organic frameworks (COFs), and so forth, have been developed to recognize and separate enantiomers. 18,19 The chiral MOFs and COFs can also serve as asymmetric catalysts due to their different binding strength with substrates or intermediates. 20,21 The chirality communications mainly include transfer and recognition.…”

“…Or a trace amount of chiral molecules induces the homochiral assembling of another type of molecules 15–17 . More recently, chiral porous materials, such as metal‐organic frameworks (MOFs), covalent organic frameworks (COFs), and so forth, have been developed to recognize and separate enantiomers 18,19 . The chiral MOFs and COFs can also serve as asymmetric catalysts due to their different binding strength with substrates or intermediates 20,21 …”

Combining metal-organic frameworks (MOFs) and covalent-organic frameworks (COFs): Emerging opportunities for new materials and applications

“…Emerging as two types of novel crystalline porous materials, metalorganic frameworks (MOFs) [1][2][3] and covalent-organic frameworks (COFs) [4][5][6] have drawn huge attentions thanks but not limited to their ultrahigh surface area, well-ordered and uniform pore structure and easy modification and functionalization. Typically, under the guidance of reticular chemistry [7][8][9][10], MOFs are constructed via the coordination bond between metal ions/secondary metal nodes and organic ligands [11][12][13][14]; while COFs are linked via the covalent bond between different organic building blocks [15][16][17][18].…”