• Title/Summary/Keyword: Metal-organic frameworks (MOFs)

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Understanding the Mechanism of Hydrogen Adsorption into Metal Organic Frameworks (Metal-Organic Framework의 수소 흡착 메커니즘의 이해)

  • Lee, Tae-Bum;Kim, Dae-Jin;Yoon, Ji-Hye;Choi, Sang-Beom;Kim, Ja-Heon;Choi, Seung-Hoon
    • 한국신재생에너지학회:학술대회논문집
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    • 2005.11a
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    • pp.634-637
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    • 2005
  • Hydrogen adsorption mechanism onto the porous metal-organic frameworks (MOFs) has been studied by density functional theory calculation. The selected functionals for the predict ion of interact ion energies between hydrogen and potential adsorption sites of MOF was utilized after the evaluation with the various functionals for interaction energy of $H_2C_6H_6$ model system the adsorption energy of hydrogen molecule into MOF was investigated with the consideration of the favorable adsorption sites and the orientations. We also calculated the second favorable adsorption sites by geometry optimization using every combination of two first absorbed hydrogen molecules. Based on the calculation of first and second adsorption sites and energies, the hydrogen adsorption into MOF follows a cooperative mechanism in which the initial metal sites initiate the propagation of the hydrogen adsorption on the whole frameworks. In addition, it was found that the interaction strength between the simple benzene ring with hydrogen is significantly reinforced when the benzene ring has been incorporated into the framework of MOFs.

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CO2/CH4 Separation in Metal-organic Frameworks: Flexibility or Open Metal Sites? (금속-유기 골격체를 이용한 CO2/CH4 분리: 플렉서블 효과와 강한 흡착 사이트 비교 연구)

  • Jung, Minji;Oh, Hyunchul
    • Membrane Journal
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    • v.28 no.2
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    • pp.136-141
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    • 2018
  • Carbon dioxide ($CO_2$) exists not only as a component of natural gas, biogas, and landfill gas, but also as a major combustion product of fossil fuels which leads to a major contributor to greenhouse gases. Hence it is essential to reduce or eliminate carbon dioxide ($CO_2$) in order to obtain high fuel efficiency of internal combustion engine, to prevent corrosion of gas transportation system, and to cope with climate change preemptively. In recent years, there has been a growing interest in not only conventional membrane-based separation but also new adsorbent-based separation technology. Particularly, in the case of metal-organic frameworks (MOFs), it has been received tremendous attentions due to its unique properties (eg : flexibility, gate effect or strong binding site such as open metal sites) which are different from those of typical porous adsorbents. Therefore, in this study, stereotype of two MOFs have been selected as its flexible MOFs (MIL-53) representative and numerous open metal sites MOFs (MOF-74) representative, and compared each other for $CO_2/CH_4$ separation performance. Furthermore, varying and changeable separation performance conditions depending on the temperature, pressure or samples' unique properties are discussed.

Catalytic Application of Metal-Organic Frameworks for Chemical Fixation of CO2 into Cyclic Carbonate (CO2로부터 5원환 탄산염의 화학적 고정화 반응을 위한 Metal-Organic Frameworks의 촉매적 응용)

  • Ji, Hoon;Naveen, Kanagaraj;Kim, Dongwoo;Cho, Deug-Hee
    • Applied Chemistry for Engineering
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    • v.31 no.3
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    • pp.258-266
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    • 2020
  • The chemical fixation of CO2 into cyclic carbonates is considered to be one of the most promising way to alleviate global warming and produce fine chemicals. In this work, the catalytic applicability of metal-organic frameworks (MOFs) as porous crystalline materials for the synthesis of five-membered cyclic carbonate from CO2 and epoxides was reviewed. In addition, we have briefly classified the materials based on their different structural features and compositions. The studies revealed that MOFs exhibited good catalytic performance towards cyclic carbonate synthesis because of the synergistic effect between the acid sites of MOFs and nucleophile. Moreover, the effect of structure of designed MOFs and mechanism for the cycloaddition of CO2 were suggested.

MOFs for the Detection of High Explosives (MOF를 이용한 극미량의 고폭화약 탐지)

  • LEE, Junwung
    • Journal of the Korea Institute of Military Science and Technology
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    • v.18 no.4
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    • pp.376-386
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    • 2015
  • MOFs(Metal-Organic Frameworks) are new kinds of materials comprised of metal ions and functional organic ligands, and have large pores in its rigid structures which give the materials various functionalities, including gas absorption, separation, drug delivery etc. Recently photoluminescence properties of MOFs and possibilities of its application to high explosive sensing technologies are drawing attentions from scientists and engineers, because these methods are simple, cheap and easy to perform detection operations. In this article the author reviews the mechanisms of photoluminescence of MOFs, the detection methods of high explosives using MOFs and recent research progresses based on the papers published mainly during last 10 years.

MOF-based Sensing Materials for Non-enzymatic Glucose Sensors

  • Jingjing Liu;Xiaoting Zha;Yajie Yang
    • Journal of Electrochemical Science and Technology
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    • v.15 no.1
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    • pp.32-50
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    • 2024
  • Diabetes mellitus is one of the common chronic diseases, seriously threating to human health. The continuous monitoring of blood glucose concentration can effectively prevent diabetic diseases. The sensing performance of glucose non-enzymatic sensors is mainly determined by working electrode materials. Metal-organic frameworks (MOFs) are recognized as promising candidate for glucose sensor application, due to its large surface areas, ordered porous structure and nearly infinite designability. In this review, the sensing performance, research progress and future challenge of non-enzymatic glucose sensors based on MOF-based materials in recent years are presented. We hope that this review would provide valuable technology guidance for high performance non-enzymatic glucose sensors based on MOFs.

Facile and Clean Synthetic Route to Non-Layered Two-Dimensional ZIF-67 Nanosheets

  • Choi, Chang-Ho
    • Clean Technology
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    • v.26 no.4
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    • pp.257-262
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    • 2020
  • Two-dimensional (2D) metal organic framework (MOF) nanosheets (NSs) have recently gained considerable interest owing to their structural advantages, such as large surface area and exposed active sites. Two different types of 2D MOF NSs have been reported, including inherently layered MOFs and non-layered ones. Although several studies on inherently layered 2D MOFs have been reported, non-layered 2D MOFs have been rarely studied. This may be because the non-layered MOFs have a strong preference to form three-dimensionality intrinsically. Furthermore, the non-layered MOFs are typically synthesized in the presence of the surfactant or modulator, and thus developing facile and clean synthetic routes is highly pursued. In this study, a facile and clean synthetic methodology to grow non-layered 2D cobalt-based zeolitic imidazolate framework (ZIF-67) NSs is suggested, without using any surfactant and modulator at room temperature. This is achieved by directly converting ultrathin α-Co(OH)2 layered hydroxide salt (LHS) NSs into non-layered 2D ZIF-67 NSs. The comprehensive characterizations were conducted to elucidate the conversion mechanism, structural information, thermal stability, and chemical composition of the non-layered 2D ZIF-67. This facile and clean approach could produce a variety of non-layered 2D MOF NS families to extend potential applications of MOF materials.

Molecular Dynamics Simulation on Hydrogen Adsorption into Catenated Metal Organic Frameworks (분자 동역학을 이용한 상호 관통된 Metal Organic Framework의 수소 흡착에 관한 연구)

  • Lee, Tae-Bum;Kim, Dae-Jin;Jung, Dong-Hyun;Kim, Ja-Heon;Choi, Seung-Hoon
    • 한국신재생에너지학회:학술대회논문집
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    • 2006.06a
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    • pp.9-12
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    • 2006
  • We performed molecular dynamics simulations on the conventional MOF, IRMOF-14 and the catenated MOF with two MOF chains, IRMOF13, to find out rational design and synthetic strategies toward efficient hydrogen storage materials. The molecular dynamics calculations were done using Universal force fields and the analysis of result was performed during the NVE dynamics after preliminary NVT dynamics at 77K. The results showed the density of adsorbed hydrogen molecules was increased in the various pores created by catenation of MOFs while the large amount of volume in conventional MOF was not effectively utilized to store hydrogen. Those calculation results commonly showed the proper control of pore si Be for hydrogen storage into MOF by catenation would be one of the efficient ways to increase hydrogen capacity of MOFs.

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Improving the DIMP Sorption Capacity Durability of Zirconium Based Metal-Organic Frameworks Coated with Polydimethylsiloxane at High Humidity (PDMS 코팅을 통한 지르코늄 기반 금속유기골격체의 고습 환경에서 DIMP 흡착 성능 지속성 개선)

  • Jang, Wonhyeong;Jeong, Sangjo
    • Applied Chemistry for Engineering
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    • v.33 no.3
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    • pp.296-301
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    • 2022
  • Due to the fact that zirconium based metal-organic frameworks (Zr-MOFs), such as UiO-66, have a large specific surface area and excellent selective adsorption capacity, Zr-MOFs are gaining attention as materials that can provide protection from the attack of chemical warfare agents in battleground. However, most of the metal-organic frameworks have an issue of selective adsorption capacity degraded by water molecules when exposed to the atmosphere, because of the weak metal-organic ligand bonds and the presence of voids. Therefore, polydimethylsiloxane (PDMS), a representative hydrophobic polymer material, was coated on the surface of UiO-66 to enhance the sustainability of the diisopropyl methylphosphonate (DIMP) sorption capacity in the battleground condition. Through the analysis of surface structure and organic functional group distribution of PDMS coated UiO-66, silicon was confirmed to be evenly coated. The contact angle increased by over 30° for the PDMS coated UiO-66, indicating that the hydrophobicity was improved. In addition, both the UiO-66 and PDMS coated UiO-66 were used as adsorbents for DIMP, a similar chemical warfare agent, to investigate the durability of adsorption capacity in a high humidity environment. The PDMS coated UiO-66 showed higher durability of adsorption capacity for 20 days than that of pristine UiO-66.

Recent Advances on MOF-assisted Atmospheric Water Harvesting at Dry Regions (수분 수착 MOF를 이용한 건조한 지역의 대기 중 워터하베스팅 기술의 최근 동향)

  • Geunho Lee;Woochul Song
    • Membrane Journal
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    • v.34 no.1
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    • pp.30-37
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    • 2024
  • As a promising method to address global water scarcity, sorbent-assisted water harvesting from air has shown great potential to deliver drinking water for inlands lacking traditional water sources. In this article, the recent studies of using metal-organic frameworks (MOFs) as sorbents to harvest atmospheric water will be introduced. Compared to the other sorbent materials such as zeolites or silica-based materials, MOFs have shown prospective properties such as the water isotherm inflection points as low as ~10%, which are suitable for harvesting water at dry regions. Due to this property, recently, MOFs have been extensively adopted to develop practical water harvesting devices that can harvest water. Since atmospheric water is accessible anywhere and anytime in the world, this technology is expected to open a new avenue in terms of securing safe water for the future.