Electrochemical performance and synthesis of graphene composite electrode materials decorated by metal organic frameworks

김석,홍지화,최미영 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.1

The recently developed mixed metal approach to metal organic frameworks (MOF) allows the integration of two different metals into the same framework. The mixed-metal approach to MOF offers exciting opportunities to get a MOF with specific features and structural complexity. In this study, we designed a simple one-step procedure for simultaneously forming graphene and adhering a mixed metal organic framework containing nickel. The structure and morphology of the composite are characterized by Fourier transform infrared spectrometer (FTIR), scanning electron microscopy (SEM). Electrochemical properties were characterized by cyclic voltammetry (CV) and charge-discharge (CD) in 6M KOH electrolyte.

Weak Coordination Bond of Chloromethane: A Unique Way to Activate Metal Node Within an Unstable Metal–Organic Framework DUT-34

Bae Jinhee,Lee Chang Yeon,Jeong Nak Cheon 대한화학회 2021 Bulletin of the Korean Chemical Society Vol.42 No.4

Activation of metal nodes in metal–organic frameworks (MOFs) has been viewed as an essential step prior to their use for various potential applications. So far, a thermal method has been most commonly employed for the activation despite its negative influence on the structural integrity of MOFs. Meanwhile, DUT-34 has been considered as an ideal platform for the above applications due to its open-metal sites (OMSs) at the Cu node. However, the activation of DUT-34 has not been successful because of its fragile characteristics. In this article, we report the coordination-chemistry-controlled activation, namely chemical route activation, using chloromethanes. By monitoring the coordination exchangeability of chloromethanes, we demonstrate that the chloromethanes can weakly coordinate at the OMSs. Further, we demonstrate that this coordination exchange is a safe activation method to retain the framework structure of DUT-34, based on the observation that the DUT-34 placed in TCM remained intact over 2 months.

금속-유기 골격체(Metal-organic Frameworks)를 활용한 물로부터의 유해 유기물의 흡착 제거

서필원 ( Pill Won Seo ),송지윤 ( Ji Yoon Song ),정성화 ( Sung Hwa Jhung ) 한국공업화학회 2016 공업화학 Vol.27 No.4

수자원의 효과적 활용을 위해 유해물질을 제거하는 기술이 중요하며 흡착이 하나의 경쟁력 있는 기술로 검토/개발되고 있다. 흡착공정이 경쟁력을 가지기 위해서는 뛰어난 성능의 흡착제 개발이 중요하다. 유기물과 무기물 모두를 함유한 금속-유기 골격체(metal-organic frameworks, MOFs)는 큰 표면적, 세공부피, 잘 정의된 세공 구조 및 용이한 기능화등으로 인해 다양한 흡착에 활용되고 있다. 본 고에서는 MOFs를 이용하여 물로부터 유해한 유기물을 흡착제거하는 기술을 요약, 정리하였다. 단순히 흡착량이나 속도를 증가하는 연구 대신에 흡착질과 흡착제 간의 상호작용의 메커니즘을 요약하였고 이를 위해 MOFs를 수정/기능화한 연구를 정리하였다. 이러한 요약으로부터 독자들은 유해물질의 흡착제거를 위한 흡착제의 필요 물성 및 수정에 대해 이해를 하게 될 것이며 흡착 외에 유기물들의 저장 및 전달에 대한 새로운 아이디어를 얻을 수 있을 것으로 기대된다. Removing hazardous materials from water resources is very important for efficient utilization of the resources, and adsorptive removal is regarded as a competitive technology when good adsorbents with high capacity/selectivity are available. Metal-organic framework (MOF), composed of both organic and inorganic (metallic) species, have been tried for various adsorptions because of huge surface area/pore volume, well-defined pore structure, and facile functionalization. In this review, we summarized technologies on adsorptive removal of hazardous organics from water mainly using MOFs as adsorbents. Instead of reporting high adsorption capacity or rate, we summarized mechanisms of interaction between adsorbates (organics) and adsorbents (MOFs) and methods to modify or functionalize MOFs for effective adsorptions. We expect for readers of this review to understand needed characteristics of adsorbents for the adsorptive removal, functionalization of MOFs for effective adsorption and so on. Moreover, they might have an idea on storage and delivery of organics via understanding of the mechanism of adsorption and interaction.

Post‐synthetic modifications in metal–organic frameworks for high proton conductivity

Sharma Amitosh,이성환,임재웅,나명수 대한화학회 2024 Bulletin of the Korean Chemical Society Vol.45 No.2

A myriad of metal ions and organic linkers can be used to produce metal–organic frameworks (MOFs) with varied functionalities, porosities, and dimensionalities. Such diversity has garnered significant research interest, particularly in leveraging MOFs as proton conductors for fuel cells. One effective approach involves introducing guest molecules into MOF pores. These molecules serve either as proton carriers or as proton‐conducting media through potential hydrogen bonding networks. This review offers an organized overview of key methodologies historically employed to achieve superprotonic conductivity in MOFs. The article systematically categorizes these tactics into three primary groups: guest molecule encapsulation, modulation at metal‐coordination sites, and ligand functionalization. We succinctly discuss the roles of proton carriers, conducting media, and the overall MOF framework, emphasizing the significance of each strategy's application. In conclusion, we provide insights into the future development of MOFs as proton conductors, rooted in the categorization and conceptual understanding of these strategies. A myriad of metal ions and organic linkers can be used to produce metal– organic frameworks (MOFs) with varied functionalities, porosities, and dimensionalities. Such diversity has garnered significant research interest, particularly in leveraging MOFs as proton conductors for fuel cells. One effective approach involves introducing guest molecules into MOF pores. These molecules serve either as proton carriers or as proton-conducting media through potential hydrogen bonding networks. This review offers an organized overview of key methodologies historically employed to achieve superprotonic conductivity in MOFs. The article systematically categorizes these tactics into three primary groups: guest molecule encapsulation, modulation at metal-coordination sites, and ligand functionalization. We succinctly discuss the roles of proton carriers, conducting media, and the overall MOF framework, emphasizing the significance of each strategy’s application. In conclusion, we provide insights into the future development of MOFs as proton conductors, rooted in the categorization and conceptual understanding of these strategies.

플래시라이트를 이용한 금속나노입자 기반 전극 및 금속유기골격체 합성 전략

임창용 ( Changyong Yim ),백새연 ( Saeyeon Baek ),박소연 ( Soyeon Park ),김하민 ( Hamin Kim ) 한국공업화학회 2020 공업화학 Vol.31 No.6

Intensive pulsed light (IPL) 기술은 빛을 millisecond 단위의 짧은 시간에 상온, 상압 환경에서 대상 물질에 조사하여 에너지를 전달한다. 이렇게 단시간에 조사되는 특징을 가진 플래시라이트(flashlight)에 대한 관심의 증대로 IPL을 이용한 금속입자의 광소결 연구가 대표적으로 이루어져 왔으며, 최근에는 IPL을 다양한 물질 합성에 적용한 사례가 발표되고 있다. 본 총설 논문은 지금까지 연구되어 밝혀진 IPL을 활용한 다양한 물질 합성 전략들에 대한 것으로 IPL 기술을 이용한 물질 합성에 대한 이해를 증진시키고자 한다. 특히, 금속나노입자의 소결을 이용한 유연 전극제작 및 금속유기골격체(metal-organic framework, MOF) 합성을 다루었다. 전극제작의 핵심 요소인 전극의 산화 저항성과 전기전도도 향상을 위한 과정을 다루었고, 금속기판으로부터 금속유기골격체를 합성하는 과정을 설명하였다. 이를 향후 IPL을 이용한 전극 제작 및 물질 합성 응용에 관한 연구를 하는 연구자에게 이해하기 쉽게 설명하고자 하였다. Intensive pulsed light (IPL) technique enables energy to be transferred to a target substance in a short time per millisecond at room temperature under an ambient atmosphere. Due to the growing interest in flashlights with excellent functionality among various technologies, light-sintering research on metal particles using IPL has been carried out representatively. Recently, examples of the application of IPL to various material synthesis have been reported. In the present article, various strategies using IPL including the manufacture of flexible electrodes and the synthesis of metal-organic frameworks were discussed. In particular, the process of improving oxidation resistance and electrical conductivity of electrodes, and also the metal-organic framework synthesis from metal surface were explained in detail. We envision that the review article can be of great help to researchers who investigate electrode manufacturing and material synthesis using IPL.

Metal–organic framework-templated hollow Co₃O₄ nanosphere aggregate/N-doped graphitic carbon composite powders showing excellent lithium-ion storage performances

Park, Seung-Keun,Kim, Jin Koo,Kim, Jong Hwa,Kang, Yun Chan Elsevier 2017 Materials characterization Vol.132 No.-

<P><B>Abstract</B></P> <P>Hollow Co<SUB>3</SUB>O<SUB>4</SUB> nanosphere aggregate/N-doped graphitic carbon (HCO/NGC) composite powders, exhibiting excellent Li-ion storage performances, were prepared by applying metal–organic frameworks (MOFs). Zeolitic imidazolate framework (ZIF)-67 cubes were reduced to produce Co/NGC composite powders. The Co/NGC composite powders were oxidized to produce cubic HCO/NGC composite powders, in which the hollow Co<SUB>3</SUB>O<SUB>4</SUB> nanospheres were uniformly covered with a NGC layer. The Co nanocrystals transformed into hollow nanospheres during oxidation via the nanoscale Kirkendall diffusion process. The unique composite structure accommodates mechanical stress owing to the void spaces within the Co<SUB>3</SUB>O<SUB>4</SUB> nanospheres; it also prevents structure collapse during cycling owing to the presence of the NGC matrix. Thus, the cubic hollow powders exhibited excellent electrochemical performances when used as an anode material in Li-ion batteries (LIBs). Following 250cycles, the HCO/NGC composite powders with 11wt% NGC delivered a discharge capacity of 1030mAhg<SUP>−1</SUP> at a current density of 1Ag<SUP>−1</SUP>. In addition, the composite powders delivered a discharge capacity of 738mAhg<SUP>−1</SUP> even at a high current density of 10Ag<SUP>−1</SUP>.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Aggregate of Co<SUB>3</SUB>O<SUB>4</SUB> hollow nanospheres was prepared by applying metal–organic frameworks. </LI> <LI> Kirkendall diffusion resulted in the formation of empty nanovoids within the Co<SUB>3</SUB>O<SUB>4</SUB> nanospheres. </LI> <LI> Aggregate of Co<SUB>3</SUB>O<SUB>4</SUB> hollow nanospheres exhibited excellent Li-ion storage performances. </LI> </UL> </P> <P><B>Graphical Abstract</B></P> <P>[DISPLAY OMISSION]</P>

Chemisorption of hydrogen sulfide by metal-organic frameworks and covalent-organic polymers based on experimental/theoretical evaluation

Lee, Min-Hee,Vikrant, Kumar,Younis, Sherif A.,Szulejko, Jan E.,Kim, Ki-Hyun Elsevier 2020 JOURNAL OF CLEANER PRODUCTION Vol.250 No.-

<P><B>Abstract</B></P> <P>The rapid expansion of modern industrial productivity has led to the ever-increasing emissions of various hazardous gaseous pollutants. In order to efficiently treat gaseous odorants like hydrogen sulfide (H<SUB>2</SUB>S), it is important to accurately assess the sorptive performance under near ambient conditions [<1 Pa at 298 K]. To this end, the performance of H<SUB>2</SUB>S sorption was investigated at 1 Pa (∼10 ppm at 298 K) inlet stream partial pressure of H<SUB>2</SUB>S in 1 bar of N<SUB>2</SUB> using three metal-organic frameworks (MOFs: MOF-199, MOF-5, and UiO-66-NH<SUB>2</SUB>), two covalent-organic polymers (COPs: CBAP-1 (EDA) and CBAP-1 (DETA)), and two commercial sorbents (Carbopack-X and activated carbon [AC]). The 10% breakthrough volume (BTV10: L g<SUP>−1</SUP>)/corresponding adsorption capacity (mg g<SUP>−1</SUP>) confirmed a noticeable advantage of MOF-199 (3040/42) over all other tested materials (i.e., MOF-5 (94/1.3) >AC (3.5/0.049) > UiO-66-NH<SUB>2</SUB> (3.1/0.043) > CBAP-1 (EDA) (2.5/0.035) > CBAP-1 (DETA) (2/0.028) > Carbopack-X (1.9/0.026)). The overall results clearly confirm that MOF-199 is an excellent chemisorbent to effectively capture gaseous H<SUB>2</SUB>S via the formation of irreversible chemical bonds with Cu–Cu site bridge (i.e., Cu–S). However, a comparison between previous (theoretical) and present (experimental) data indicates substantial divergence in the partition coefficient (PC: mol kg<SUP>−1</SUP> Pa<SUP>−1</SUP>) data of MOF-199 (e.g., PC (at BTV5) = 16.0 (experiment) vs. PC = 7.5E-05 (simulation)). These divergences with the computed PC values are attributed to the fact that the crystal lattice of MOF-199 relaxes to a more thermodynamically stable structure under real-experimental conditions. In contrast, the assumption of frozen geometry of MOF-199 crystal lattice used for the theoretical simulation (by density functional theory) unrealistically underestimated the H<SUB>2</SUB>S adsorption capacity.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Functional group effects on a metal-organic framework catalyst for CO₂ cycloaddition

Noh, Jinmi,Kim, Youngik,Park, Hyojin,Lee, Jihyun,Yoon, Minyoung,Park, Myung Hwan,Kim, Youngjo,Kim, Min THE KOREAN SOCIETY OF INDUSTRIAL AND ENGINEERING 2018 JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY -S Vol.64 No.-

<P><B>Abstract</B></P> <P>A variety of metal-organic frameworks (MOFs) have been reported as efficient catalysts for CO<SUB>2</SUB> fixation reactions, such as cycloaddition to cyclic carbonates. The permanent porosity of the frameworks and the Lewis acidity of the MOF metal sites have been considered as the major contributors to the catalytic activity in the cycloaddition of CO<SUB>2</SUB>. In this study, we have, instead, focused on the effects of the organic functional groups for effective catalytic ability. A total of eight different functionalized Zr-based MOFs were tested. It was revealed that the non-functionalized pristine UiO-66 MOF (UiO=University of Oslo) showed the best conversion at low temperature (77% at 50°C), whereas the hydroxy-functionalized UiO-66-OH MOF displayed the best conversion at high temperature (91% at 140°C). The Zr-MOF could be recycled up to four times without a significant decrease in the reactivity.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The organic functional group effects on MOF-catalyzed CO<SUB>2</SUB> cycloaddition have been examined. </LI> <LI> Non-functionalized Zr-based MOF, UiO-66 showed the best catalytic activity at 50°C. </LI> <LI> The hydroxy-functionalized UiO-66-OH performed cyclic organic carbonate synthesis efficiently at 140°C. </LI> <LI> Various epoxides were successfully converted to cyclic organic carbonates, and the Zr-MOF catalyst could be recycled by simple centrifugation. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Functional group effects on a metal-organic framework catalyst for CO2 cycloaddition

노진미,김영익,박효진,이지현,윤민영,박명환,김영조,김민 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.64 No.-

A variety of metal-organic frameworks (MOFs) have been reported as efficient catalysts for CO2 fixation reactions, such as cycloaddition to cyclic carbonates. The permanent porosity of the frameworks and the Lewis acidity of the MOF metal sites have been considered as the major contributors to the catalytic activity in the cycloaddition of CO2. In this study, we have, instead, focused on the effects of the organic functional groups for effective catalytic ability. A total of eight different functionalized Zr-based MOFs were tested. It was revealed that the non-functionalized pristine UiO-66 MOF (UiO = University of Oslo) showed the best conversion at low temperature (77% at 50 °C), whereas the hydroxy-functionalized UiO-66-OH MOF displayed the best conversion at high temperature (91% at 140 °C). The Zr-MOF could be recycled up to four times without a significant decrease in the reactivity.

ZIF-67을 이용한 이기능성 촉매의 최신연구 동향

김상준,조승근,박길령,이은빈,이재민,이정우 한국재료학회 2022 한국재료학회지 Vol.32 No.2

Metal-organic frameworks (MOFs) are widely used in various fields because they make it easy to control porous structures according to combinations of metal ions and organic linkers. In addition, ZIF (zeolitic imidazolate framework), a type of MOF, is made up of transition metal ions such as Co2+ or Zn2+ and linkers such as imidazole or imidazole derivatives. ZIF- 67, composed of Co2+ and 2-methyl imidazole, exhibits both chemical stability and catalytic activity. Recently, due to increasing need for energy technology and carbon-neutral policies, catalysis applications have attracted tremendous research attention. Moreover, demand is increasing for material development in the electrocatalytic water splitting and metal-air battery fields; there is also a need for bifunctional catalysts capable of both oxidation/reduction reactions. This review summarizes recent progress of bifunctional catalysts for electrocatalytic water splitting and metal-air batteries using ZIF-67. In particular, the field is classified into areas of thermal decomposition, introduction of heterogeneous elements, and complex formation with carbonbased materials or polyacrylonitrile. This review also focuses on synthetic methods and performance evaluation.