Publications by authors named "Moonhyun Oh"

The components and structures of metal-organic frameworks (MOFs) are critical two factors that influence their properties and prospective applications. Moreover, the construction of complex MOFs integrating multiple components holds promise to achieve MOFs with unique properties. However, constructing complex MOFs with an intended 3D spatial arrangement of the multiple components remains underdeveloped.

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ConspectusOverflowing metal-organic frameworks (MOFs) have been synthesized from a wide range of metal and organic components for specific purposes and intellectual curiosity. Each MOF has unique chemical and structural characteristics directed by the incorporated components, metal ions (or clusters), organic linkers, and their intrinsic coordination interactions. These incorporated components and structural characteristics are two pivotal factors influencing MOFs' fundamental properties and subsequent applications.

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The fabrication of flexible composites by integrating metal-organic frameworks (MOFs) with flexible substrates is a critical strategy for developing advanced materials with excellent feasibility and processability. These flexible MOF-based composites play a particularly important role in the separation and purification processes. However, several drawbacks remain challenge to overcome such as long processing time, high-cost, complicated processes, or harsh reaction conditions.

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Here, we report the synthesis of three-dimensional plasmonic nanolenses for strong near-field focusing. The nanolens exhibits a distinctive structural arrangement composed of nanoporous sponge-like networks within their interior. We denote these novel nanoparticles as "Au octahedral nanosponges" (Au Oh NSs).

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Efficient adsorption of hazardous substances from the environment is crucial owing to the considerable risks they pose to both humans and ecosystems. Consequently, the development of porous materials with strong adsorption capabilities for hazardous substances, such as chemical warfare agents (CWAs), is pivotal for safeguarding human lives. Specifically, the early-stage adsorption proficiency of the adsorbents plays a vital role in determining their effectiveness as ideal adsorbents.

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The development of effective porous adsorbents plays a vital role in eliminating hazardous substances from the environment. Toxic chemicals, including chemical warfare agents (CWAs), pose significant risks to both humans and ecosystems, highlighting the urgency to create efficient porous adsorbents. Therefore, substantial attention has been directed towards advancing adsorption techniques for the successful eradication of CWAs from the environment.

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Article Synopsis
  • * Four different morphologies of ZIF-8 were prepared, each displaying unique surface charges that influenced their ability to adsorb CWA simulants like CEES and DMMP.
  • * The cubic ZIF-8 variant, which had the most positive surface charge, showed the highest adsorption capacity and maintained excellent recyclability without significant structural changes.
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The structures of metal-organic frameworks (MOFs) are typically determined by the building blocks that compose them and the conditions under which they are formed. MOFs tend to adopt a thermodynamically and/or kinetically stable structure (naturally preferred form). Thus, constructing MOFs with naturally nonpreferred structures is a challenging task, as it requires avoiding the easier pathway toward a naturally preferred MOF.

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Numerous open metal sites and well-developed micropores are the two most significant characteristics that should be imparted to design metal-organic frameworks (MOFs) as effective catalysts. However, the construction of the best MOF catalyst with both these characteristics is challenging because the creation of numerous open metal sites generally triggers some structural collapse of the MOF. Herein, we report the construction of well-structured but defected MOFs through the growth of defected MOFs, where some of the original organic linkers were replaced with analog organic linkers, on the surface of a crystalline MOF template (MOF-on-MOF growth).

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The structural control of metal-organic frameworks (MOFs) is essential for the development of superlative MOFs because the structural features of MOFs and their components play a critical role in determining their properties, and ultimately, their applications. The best components to endow the desired properties for MOFs are available via the appropriate choice from many existing chemicals or synthesizing new ones. However, to date, considerably less information exists regarding fine-tuning the MOF structures.

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Precisely constructed porous composites containing catalytically active nanoparticles can stabilize unstable nanoparticles, thus improving catalytic activity and longevity while preventing agglomeration of active nanoparticles. Herein, we report the confined incorporation of highly active metal nanoparticles within a metal-organic framework support and efficient catalytic performances in the reduction of organic pollutants, such as methylene blue (MB) and 4-nitrophenol (4-NP). UiO-66-based porous composites (M@UiO-66, M = Pt or Ag) containing well-dispersed metal nanoparticles are constructed via the one-step thermal treatment of UiO-66 implanted with metal ions (UiO-66/M, M = Pt or Ag).

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The preparation of metal-organic frameworks (MOFs) having many open metal sites is an excellent approach for the development of highly active MOF-based catalysts. Herein, well-defined rice-shaped MOF-74 microparticles having structural defects are prepared by incorporating two analogous organic linkers [2,5-dihydroxy-1,4-bezenedicarboxylic acid (DHBDC) and 2-hydroxy-1,4-benzenedicarboxylic acid (HBDC)] within the MOF-74 structure. The replacement of some of DHBDC in MOF-74 by HBDC causes the structural defects (excluding some of the bridged hydroxyl groups), and these structural defects provide the additional open metal sites within MOF-74.

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Constructing metal-organic frameworks (MOFs) to have a desired structure from the given components is critical to achieve ideal MOFs with optimal properties. However, thermodynamics and/or kinetics typically impose a restriction on MOF structures. Here, we report the MOF farming concept to produce a naturally nonpreferred structure from the given components.

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Incorporation of metal nanocatalysts within a well-defined porous support is of great importance for stabilizing unstable metal nanocatalysts, so that they display an effective and long-lasting catalytic activity. In particular, metal-organic frameworks (MOFs) with a wide range of structures serve as excellent porous supports for stabilizing unstable nanocatalysts. In addition, the development of inexpensive metal nanocatalysts is necessary to replace expensive noble metal nanocatalysts.

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Well-organized construction of hybrid metal-organic frameworks (MOFs) with complicated structures or components is a great importance because of their potential usefulness. In this regard, the conjugation of more than two MOFs, which have dissimilar components and/or structures, is a smart strategy for the production of hybrid MOFs. MOF-on-MOF growth is fundamental for the conjugation of two MOFs and should be deeply understood for the finely controlled conjugation and for the formation of well-organized hybrid MOFs.

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The structural, compositional, and morphological features of metal-organic frameworks (MOFs) govern their properties and applications. Construction of hybrid MOFs with complicated structures, components, or morphologies is significant for the development of well-organized MOFs. An advanced route is reported for construction of atypical hybrid MOFs with unique morphologies and complicated components: 1) MOF-on-MOF growth of a 3D zeolitic imidazolate framework (ZIF) on a ZIF-L template, 2) etching of a part of the 2D ZIF-L template, and 3) structural transformation of 2D ZIF-L into 3D ZIF.

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The structural dimension of metal-organic frameworks (MOFs) is of great importance in defining their properties and thus applications. In particular, 2D layered MOFs are of considerable interest because of their useful applications, which are facilitated by unique structural features of 2D materials, such as a large number of open active sites and high surface areas. Herein, this work demonstrates a methodology for the selective synthesis of a 2D layered MOF in the presence of the competitive formation of a 3D MOF.

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The development of new electrocatalysts for electrochemical oxygen reduction to replace expensive and rare platinum-based catalysts is an important issue in energy storage and conversion research. In this context, conductive and porous metal-organic frameworks (MOFs) are considered promising materials for the oxygen reduction reaction (ORR) due to not only their high surface area and well-developed pores but also versatile structural features and chemical compositions. Herein, the preparation of bimetallic conductive 2D MOFs (Co Ni -CATs) are reported for use as catalysts in the ORR.

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The unbalanced MOF-on-MOF growth of MIL-88A on the MIL-88B template, where both MOFs have a similar three-dimensional hexagonal structure but with mismatched cell parameters, results in the formation of an atypical lopsided core-shell of MIL-88B@MIL-88A with an off-centered core. The formation mechanism of the lopsided core-shell of MIL-88B@MIL-88A is verified via monitoring the growth process.

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A convenient method for the confined incorporation of highly active bimetallic PdCo nanocatalysts within a hollow and porous metal-organic framework (MOF) support is presented. Several chemical conversions occur simultaneously during the one-step low temperature pyrolysis of well-designed polystyrene@ZIF-67/Pd core-shell microspheres, where ZIF (zeolitic imidazolate framework) is a subclass of MOF: the polystyrene core is removed, resulting in a beneficial hollow and porous ZIF support; the ZIF-67 shell acts as a well-defined porous support and as a felicitous Co supplier for metal nanoparticle formation; and Pd and Co are reduced to form catalytically active bimetallic PdCo nanoparticles in the well-defined micropores, inducing the confined growth of PdCo nanoparticles with excellent dispersity.

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Porous metal-organic frameworks (MOFs) are interesting materials owing to their interesting structural features and their many useful properties and applications. In particular, the structural features are greatly important to optimize the MOFs' porosities and so properties. Indeed, the MOFs' well-developed micropore and high surface area are the most important structural features, and as such, many practical applications of MOFs originate from these structural features.

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The conjugation of metal-organic frameworks (MOFs) with other materials is an excellent strategy for the production of advanced materials having desired properties and so appropriate applicability. In particular, the integration of MOFs with a flexible paper is expected to form valuable materials in separation technology. Here we report a simple method for the generation of MOF papers through the compact and uniform growth of MOF nanoparticles on the cellulose surface of a carboxymethylated filter paper.

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The growth of one metal-organic framework (MOF) on another MOF for constructing a heterocompositional hybrid MOF is an interesting research topic because of the curiosity regarding the occurrence of this phenomenon and the value of hybrid MOFs as multifunctional materials or routes for fine-tuning MOF properties. In particular, the anisotropic growth of MOF on MOF is fascinating for the development of MOFs possessing atypical shapes and heterostructures or abnormal properties. Herein, we clarify the understanding of growth behavior of a secondary MOF on an initial MOF template, such as isotropic or anisotropic ways associated with their cell parameters.

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The controlled formation of metal-organic frameworks (MOFs) or coordination polymers (CPs) with suitable components and structural features is one of the most important themes in MOF research. In particular, the reliable preparation of hybrid MOFs containing more than two different kinds of metal ions or organic linkers and a comprehensive understanding of the structural flexibility of MOFs are the central issues for the production of MOFs with the desired properties. We report the synthesis of micro-sized hybrid MOF particles [also known as coordination polymer particles (CPPs)] containing two or three kinds of metal ions in each particle: {FeMM'}-MIL-88B (MIL stands for Materials of Institut Lavoisier, M and M' = Ga, Co, or Mn).

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Au or Ag nanoparticles-embedded hollow carbon spheres, which display outstanding catalytic activity and excellent recyclability, are prepared by a one-step pyrolysis of metal-organic framework (MOF) hybrids consisting of polystyrene cores and MOF shells loaded with noble metal ions (polystyrene@ZIF-8/M(n+) ; M(n+) = Au(3+) or Ag(+) ).

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