Search

US-20260124599-A1 - METAL-ORGANIC FRAMEWORK WITH 3-DIMENSIONAL POROUS NETWORK STRUCTURE, ADSORBENT INCLUDING THE SAME, AND METHOD OF PREPARING THE METAL-ORGANIC FRAMEWORK WITH 3-DIMENSIONAL POROUS NETWORK STRUCTURE

US20260124599A1US 20260124599 A1US20260124599 A1US 20260124599A1US-20260124599-A1

Abstract

Provided are a metal-organic framework with a three-dimensional porous network structure, an adsorbent including the same, and a method of preparing the metal-organic framework with a three-dimensional porous network structure. The metal-organic framework with a three-dimensional porous network structure includes: a Zn 4 O cluster; and two or more types of carboxyl group-based aromatic ligands having different degrees of bulkiness, wherein one of the carboxyl group-based aromatic ligands includes a carboxyl group-based aromatic ligand including a C4-C8 alkoxy group, an opening is defined by the carboxyl group-based aromatic ligand, and the opening has a multivariated size due to vibration of a pendant chain of the C4-C8 alkoxy group.

Inventors

  • Hoi Ri Moon
  • Junsu HA
  • Youn-Sang Bae
  • Kwang Hyun OH
  • Jihyun Park
  • Seungjin LEE
  • Kyu-Min RYOUM

Assignees

  • EWHA UNIVERSITY - INDUSTRY COLLABORATION FOUNDATION
  • UIF (UNIVERSITY INDUSTRY FOUNDATION), YONSEI UNIVERSITY

Dates

Publication Date
20260507
Application Date
20251107
Priority Date
20241107

Claims (20)

  1. 1 . A metal-organic framework with a three-dimensional porous network structure, comprising: a Zn 4 O cluster; and two or more types of carboxyl group-based aromatic ligands having different degrees of bulkiness, wherein one of the carboxyl group-based aromatic ligands comprises a carboxyl group-based aromatic ligand including a C4-C8 alkoxy group, an opening is defined by the carboxyl group-based aromatic ligands, and the opening has a multivariated size due to vibration of a pendant chain of the C4-C8 alkoxy group.
  2. 2 . The metal-organic framework of claim 1 , wherein the carboxyl group-based aromatic ligand comprises an unsubstituted carboxyl group-based aromatic ligand and a carboxyl group-based aromatic ligand including a C4-C8 alkoxy group.
  3. 3 . The metal-organic framework of claim 1 , wherein the carboxyl group-based aromatic ligand comprises 1,4-benzenedicarboxylate and 2,5-bis(alkoxy)benzenecarboxylate represented by Formula 2 below: wherein in Formula 2, R 1 and R 2 are each independently an unsubstituted C4-C8 alkoxy group.
  4. 4 . The metal-organic framework of claim 1 , wherein a major axis diameter of the opening is 1.5 Å to 4.2 Å.
  5. 5 . The metal-organic framework of claim 1 , wherein the pendant chain of the C4-C8 alkoxy group of the carboxyl group-based aromatic ligand including a C4-C8 alkoxy group is densely distributed in the opening.
  6. 6 . The metal-organic framework of claim 5 , wherein an opening smaller than the opening is additionally defined in the opening by the pendant chain of the C4-C8 alkoxy group.
  7. 7 . The metal-organic framework of claim 6 , wherein the pendant chain of the C4-C8 alkoxy group narrows a distance between a target molecule and the Zn 4 O cluster in the smaller opening to enhance interactions therebetween.
  8. 8 . The metal-organic framework of claim 1 , wherein the metal-organic framework has a core-shell structure, and a ligand located in the shell is bulkier than a ligand located in the core.
  9. 9 . The metal-organic framework of claim 8 , wherein an opening of the shell is a space for capturing the target molecule, and an opening of the core is a space for storing the target molecule.
  10. 10 . The metal-organic framework of claim 9 , wherein the target molecule is ethane (C 2 H 6 ) or xenon (Xe).
  11. 11 . The metal-organic framework of claim 1 , wherein a proportion of the bulkier ligand among the two or more types of carboxyl group-based aromatic ligands increases from a center of the metal-organic framework to the surface of the metal-organic framework, according to a crystallization rate.
  12. 12 . The metal-organic framework of claim 11 , wherein a proportion of the bulkier ligand present on the surface is 80 wt % or more based on a total weight of the metal-organic framework.
  13. 13 . The metal-organic framework of claim 1 , wherein a total volume of the opening is 0.50 cm 3 /g or more based on a total volume of the metal-organic framework.
  14. 14 . The metal-organic framework of claim 1 , wherein the metal-organic framework selectively separates ethylene (C 2 H 4 ) gas from a mixed gas of ethylene (C 2 H 4 ) and ethane (C 2 H 6 ).
  15. 15 . The metal-organic framework of claim 1 , wherein the metal-organic framework selectively separates krypton (Kr) gas from a mixed gas of xenon (Xe) and krypton (Kr).
  16. 16 . An adsorbent comprising the metal-organic framework of claim 1 .
  17. 17 . A method of preparing a metal-organic framework with a three-dimensional porous network structure, the method comprising: preparing a solution including a first carboxyl group-based aromatic ligand; and adding a Zn 4 O cluster precursor solution, and a first metal-organic framework including a Zn 4 O cluster and a second carboxyl group-based aromatic ligand to the solution including the first carboxyl group-based aromatic ligand, followed by heat-setting at a temperature of 70° C. to 95° C. and then leaving to stand to obtain a second metal-organic framework crystal having a core-shell structure, wherein the first carboxyl group-based aromatic ligand is a carboxyl group-based aromatic ligand including a C4-C8 alkoxy group, the second carboxyl group-based aromatic ligand is less bulky than the first carboxyl group-based aromatic ligand, an opening is defined by the first carboxyl group-based aromatic ligand and the second carboxyl group-based aromatic ligand, and in the second metal-organic framework crystal, the first carboxyl group-based aromatic ligand is located in the shell, and the second carboxyl group-based aromatic ligand is located in the core.
  18. 18 . (canceled)
  19. 19 . The method of claim 17 , wherein the opening has a multivariated size due to vibration of a pendant chain of the C4-C8 alkoxy group.
  20. 20 . (canceled)

Description

TECHNICAL FIELD The present disclosure relates to a metal-organic framework with a three-dimensional porous network structure, an adsorbent including the same, and a method of preparing the metal-organic framework with a three-dimensional porous network structure. BACKGROUND ART Extensive studies have been conducted on metal-organic frameworks (MOFs) for various gas-separation applications because MOFs may be designed as structures with high specific surface area, porosity, and flexibility. However, in some cases, it is difficult to selectively separate a desired gas with high purity due to a small difference between kinetic diameters of mixed gas molecules, or significant cost and energy are required depending on separation conditions of mixed gases. For example, in order to selectively separate a desired gas with high purity, additional processes such as adsorption and desorption may be required or processes need to be carried out in an environment under cryogenic conditions. To solve these problems, hydrogen-bonded organic frameworks (HOFs), which rely on characteristics of weak hydrogen bonds, have been used, or MOFs with reduced pore sizes under humid conditions have been utilized. However, these approaches have not achieved the levels required to selectively and efficiently separate gases with high purity. Meanwhile, among characteristics of metal-organic frameworks (MOFs), arrangement of openings, i.e., pores, plays an important role in determining gas separation and adsorption performance. However, it is difficult to obtain precise arrangement and adjustment of MOFs under dry conditions. Therefore, there is a need to develop a metal-organic framework (MOF) having a novel structure, which, by adjusting the sizes of fine pores and arranging the pores without changing the shape of the MOF, exhibits improved selectivity, separation stability, separation efficiency, and capacity for a gas to be separated under dry conditions, an adsorbent including the MOF, and a method of preparing the MOF. DISCLOSURE OF INVENTION Technical Problem Provided is a metal-organic framework with a 3-dimensional porous network structure having improved selectivity, separation stability, separation efficiency, and capacity for a gas to be separated under dry conditions. Provided is an adsorbent including the metal-organic framework. Provided is a method of preparing the metal-organic framework with a 3-dimensional porous network structure, capable of efficiently, selectively separating a gas to be separated under dry conditions. Solution to Problem According to an aspect of the present disclosure, a metal-organic framework with a 3-dimensional porous network structure includes: a Zn4O cluster; andtwo or more types of carboxyl group-based aromatic ligands having different bulkiness,wherein one of the carboxyl group-based aromatic ligands includes a carboxyl group-based aromatic ligand including a C4-C8 alkoxy group,an opening is defined by the carboxyl group-based aromatic ligands, andthe opening has a multivariated size due to vibration of a pendant chain of the C4-C8 alkoxy group. The carboxyl group-based aromatic ligand may include an unsubstituted carboxyl group-based aromatic ligand and a carboxyl group-based aromatic ligand including a C4-C8 alkoxy group. The carboxyl group-based aromatic ligand may include 1,4-benzenedicarboxylate and 2,5-bis(alkoxy)benzenecarboxylate represented by Formula 2 below: in Formula 2,R1, and R2 are each independently an unsubstituted C4-C8 alkoxy group. A major axis diameter of the opening is 1.5 Å to 4.2 Å. The pendant chain of the C4-C8 alkoxy group of the carboxyl group-based aromatic ligand including a C4-C8 alkoxy group may be densely distributed in the opening. An opening smaller than the opening may be additionally defined in the opening by the pendant chain of the C4-C8 alkoxy group. The pendant chain of the C4-C8 alkoxy group may narrow a distance between a target molecule and the Zn4O cluster in the smaller opening to enhance interactions therebetween. The metal-organic framework has a core-shell, wherein a ligand located in the shell has a bulkier structure than a ligand located in the core. The opening of the shell may be a space for capturing the target molecule, and the opening of the core may be a space for storing the target molecule. The target molecule may be ethane (C2H6) or xenon (Xe). The metal-organic framework may have a structure in which a proportion of the bulkier ligand gradually increases from the center to the surface among the two or more carboxyl group-based aromatic ligands. A proportion of the bulkier ligand present on the surface is 80 vt % or more based on a total volume of the metal-organic framework. A total volume of the openings may be 0.50 cm3/g or more based on a total volume of the metal-organic framework. The metal-organic framework may selectively separate ethylene (C2H4) from a mixed gas of ethylene (C2H4) and ethane (C2H6). The metal-organic frame