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Start Over Descriptor "metal−organic framework" Journal acs applied materials & interfaces
8 results on '"metal−organic framework"'

1. Flexible Zn-MOF with Rare Underlying scu Topology for Effective Separation of C6 Alkane Isomers

Author

Velasco, Ever, Xian, Shikai, Wang, Hao, Teat, Simon J, Olson, David H, Tan, Kui, Ullah, Saif, Popp, Thomas M Osborn, Bernstein, Ashley D, Oyekan, Kolade A, Nieuwkoop, Andrew J, Thonhauser, Timo, and Li, Jing

Subjects
Chemical Sciences, Physical Chemistry, Affordable and Clean Energy, metal-organic framework, kinetic separation, molecular sieving, hydrocarbon, flexible structure, alkane isomers, metal−organic framework, Engineering, Nanoscience & Nanotechnology, Chemical sciences, Physical sciences
Abstract

Adsorptive separation by porous solids provides an energy-efficient alternative for the purification of important chemical species compared to energy-intensive distillations. Particularly, the separation of linear hexane isomers from its branched counterparts is crucial to produce premium grade gasoline with high research octane number (RON). Herein, we report the synthesis of a new, flexible zinc-based metal-organic framework, [Zn5(μ3-OH)2(adtb)2(H2O)5·5 DMA] (Zn-adtb), constructed from a butterfly shaped carboxylate linker with underlying (4,8)-connected scu topology capable of separating the C6 isomers nHEX, 3MP, and 23DMB. The sorbate-sorbent interactions and separation mechanisms were investigated and analyzed through in situ FTIR, solid state NMR measurements and computational modeling. These studies reveal that Zn-adtb discriminates the nHEX/3MP isomer pair through a kinetic separation mechanism and the nHEX/23DMB isomer pair through a molecular sieving mechanism. Column breakthrough measurements further demonstrate the efficient separation of linear nHEX from the mono- and dibranched isomers.

Published
2021

2. Enhanced Thermal Conductivity in a Diamine-Appended Metal–Organic Framework as a Result of Cooperative CO2 Adsorption

Author

Babaei, Hasan, Lee, Jung-Hoon, Dods, Matthew N, Wilmer, Christopher E, and Long, Jeffrey R

Subjects
Macromolecular and Materials Chemistry, Chemical Sciences, Climate Action, metal-organic framework, diamine-M-2(dobpdc), heat transfer, CO2, capture, phonon scattering, CO2 capture, diamine−M2(dobpdc), metal−organic framework, Engineering, Nanoscience & Nanotechnology, Chemical sciences, Physical sciences
Abstract

Diamine-appended variants of the metal-organic framework M2(dobpdc) (M = Mg, Mn, Fe, Co, Zn; dobpdc4- = 4,4'-dioxidobiphenyl-3,3'-dicarboxylate) exhibit exceptional CO2 capture properties owing to a unique cooperative adsorption mechanism, and thus hold promise for use in the development of energy- and cost-efficient CO2 separations. Understanding the nature of thermal transport in these materials is essential for such practical applications, however, as temperature rises resulting from exothermic CO2 uptake could potentially offset the energy savings offered by such cooperative adsorbents. Here, molecular dynamics (MD) simulations are employed in investigating thermal transport in bare and e-2-appended Zn2(dobpdc) (e-2 = N-ethylethylenediamine), both with and without CO2 as a guest. In the absence of CO2, the appended diamines function to enhance thermal conductivity in the ab-plane of e-2-Zn2(dobpdc) relative to the bare framework, as a result of noncovalent interactions between adjacent diamines that provide additional heat transfer pathways across the pore channel. Upon introduction of CO2, the thermal conductivity along the pore channel (the c-axis) increases due to the cooperative formation of metal-bound ammonium carbamates, which serve to create additional heat transfer pathways. In contrast, the thermal conductivity of the bare framework remains unchanged in the presence of zinc-bound CO2 but decreases in the presence of additional adsorbed CO2.

Published
2020

3. Photocatalytic Hydrogen Generation from a Visible-Light-Responsive Metal–Organic Framework System: Stability versus Activity of Molybdenum Sulfide Cocatalysts

Author

Nguyen, Tu N, Kampouri, Stavroula, Valizadeh, Bardiya, Luo, Wen, Ongari, Daniele, Planes, Ophélie Marie, Züttel, Andreas, Smit, Berend, and Stylianou, Kyriakos C

Subjects
Affordable and Clean Energy, metal-organic framework, hydrogen, molybdenum sulfide, photocatalysis, visible light, metal−organic framework, Chemical Sciences, Engineering, Nanoscience & Nanotechnology
Abstract

We report the use of two earth abundant molybdenum sulfide-based cocatalysts, Mo3S132- clusters and 1T-MoS2 nanoparticles (NPs), in combination with the visible-light active metal-organic framework (MOF) MIL-125-NH2 for the photocatalytic generation of hydrogen (H2) from water splitting. Upon irradiation (λ ≥ 420 nm), the best-performing mixtures of Mo3S132-/MIL-125-NH2 and 1T-MoS2/MIL-125-NH2 exhibit high catalytic activity, producing H2 with evolution rates of 2094 and 1454 μmol h-1 gMOF-1 and apparent quantum yields of 11.0 and 5.8% at 450 nm, respectively, which are among the highest values reported to date for visible-light-driven photocatalysis with MOFs. The high performance of Mo3S132- can be attributed to the good contact between these clusters and the MOF and the large number of catalytically active sites, while the high activity of 1T-MoS2 NPs is due to their high electrical conductivity leading to fast electron transfer processes. Recycling experiments revealed that although the Mo3S132-/MIL-125-NH2 slowly loses its activity, the 1T-MoS2/MIL-125-NH2 retains its activity for at least 72 h. This work indicates that earth-abundant compounds can be stable and highly catalytically active for photocatalytic water splitting, and should be considered as promising cocatalysts with new MOFs besides the traditional noble metal NPs.

Published
2018

4. Combining In Situ Techniques (XRD, IR, and 13C NMR) and Gas Adsorption Measurements Reveals CO2-Induced Structural Transitions and High CO2/CH4 Selectivity for a Flexible Metal–Organic Framework JUK-8

Author

Roztocki, Kornel, Rauche, Marcus, Bon, Volodymyr, Kaskel, Stefan, Brunner, Eike, and Matoga, Dariusz

Subjects
flexibility, separation, metal−organic framework, adsorption, in situ techniques, Research Article
Abstract

Flexible metal–organic frameworks (MOFs) are promising materials in gas-related technologies. Adjusting the material to processes requires understanding of the flexibility mechanism and its influence on the adsorption properties. Herein, we present the mechanistic understanding of CO2-induced pore-opening transitions of the water-stable MOF JUK-8 ([Zn(oba)(pip)]n, oba2– = 4,4′-oxybis(benzenedicarboxylate), pip = 4-pyridyl-functionalized benzene-1,3-dicarbohydrazide) as well as its potential applicability in gas purification. Detailed insights into the global structural transformation and subtle local MOF–adsorbate interactions are obtained by three in situ techniques (XRD, IR, and 13CO2-NMR). These results are further supported by single-crystal X-ray diffraction (SC-XRD) analysis of the solvated and guest-free phases. High selectivity toward carbon dioxide derived from the single-gas adsorption experiments of CO2 (195 and 298 K), Ar (84 K), O2 (90 K), N2 (77 K), and CH4 (298 K) is confirmed by high-pressure coadsorption experiments of the CO2/CH4 (75:25 v/v) mixture at different temperatures (288, 293, and 298 K) and in situ NMR studies of the coadsorption of 13CO2/13CH4 (50:50 v/v; 195 K).

Published
2021

5. Natural wood-based catalytic membrane microreactors for continuous hydrogen generation

Author

Tu, Kunkun, Büchele, Simon, Mitchell, Sharon, Stricker, Laura, Liu, Chun, Goldhahn, Christian, Allaz, Julien, Ding, Yong, Günther, Roman, Zhang, Zhidong, Sun, Jianguo, Stucki, Sandro, Panzarasa, Guido, Zeeman, Samuel C, Burgert, Ingo, Pérez-Ramírez, Javier, Keplinger, Tobias, Tu, Kunkun, Büchele, Simon, Mitchell, Sharon, Stricker, Laura, Liu, Chun, Goldhahn, Christian, Allaz, Julien, Ding, Yong, Günther, Roman, Zhang, Zhidong, Sun, Jianguo, Stucki, Sandro, Panzarasa, Guido, Zeeman, Samuel C, Burgert, Ingo, Pérez-Ramírez, Javier, and Keplinger, Tobias

Abstract

The development of controlled processes for continuous hydrogen generation from solid-state storage chemicals such as ammonia borane is central to integrating renewable hydrogen into a clean energy mix. However, to date, most reported platforms operate in batch mode, posing a challenge for controllable hydrogen release, catalyst reusability, and large-scale operation. To address these issues, we developed flow-through wood-based catalytic microreactors, characterized by inherent natural oriented microchannels. The prepared structured catalysts utilize silver-promoted palladium nanoparticles supported on metal-organic framework (MOF)-coated wood microreactors as the active phase. Catalytic tests demonstrate their highly controllable hydrogen production in continuous mode, and by adjusting the ammonia borane flow and wood species, we reach stable productivities of up to 10.4 cmH23 min-1 cmcat-3. The modular design of the structured catalysts proves readily scalable. Our versatile approach is applicable for other metals and MOF combinations, thus comprising a sustainable and scalable platform for catalytic dehydrogenations and applications in the energy-water nexus.

Published
2022

6. Support Effect of Metal-Organic Frameworks on Ethanol Production through Acetic Acid Hydrogenation

Author

Miho Yamauchi, Nobutaka Maeda, Masaaki Sadakiyo, Shotaro Yoshimaru, Jenny Pirillo, Yuh Hijikata, and Kenichi Kato

Subjects
Materials science, metal−organic framework, Ethyl acetate, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, Catalysis, chemistry.chemical_compound, Acetic acid, Adsorption, ethanol production, General Materials Science, catalysis, nanoparticle, fungi, Substrate (chemistry), metal-organic framework, 021001 nanoscience & nanotechnology, 0104 chemical sciences, support effect, chemistry, Yield (chemistry), Metal-organic framework, hydrogenation, 0210 nano-technology, Selectivity, Nuclear chemistry, Research Article
Abstract

We present a systematic study on the support effect of metal-organic frameworks (MOFs), regarding substrate adsorption. A remarkable enhancement of both catalytic activity and selectivity for the ethanol (EtOH) production reaction through acetic acid (AcOH) hydrogenation (AH) was observed on Pt nanoparticles supported on MOFs. The systematic study on catalysis using homogeneously loaded Pt catalysts, in direct contact with seven different MOF supports (MIL-125-NH2, UiO-66-NH2, HKUST-1, MIL-101, Zn-MOF-74, Mg-MOF-74, and MIL-121) (abbreviated as Pt/MOFs), found that MOFs having a high affinity for the AcOH substrate (UiO-66-NH2 and MIL-125-NH2) showed high catalytic activity for AH. This is the first demonstration indicating that the adsorption ability of MOFs directly accelerates catalytic performance using the direct contact between the metal and the MOF. In addition, Pt/MIL-125-NH2 showed a remarkably high EtOH yield (31% at 200 degrees C) in a fixed-bed flow reactor, which was higher by a factor of more than 8 over that observed for Pt/TiO2, which was the best Pt-based catalyst for this reaction. Infrared spectroscopy and a theoretical study suggested that the MIL-125-NH2 support plays an important role in high EtOH selectivity by suppressing the formation of the byproduct, ethyl acetate (AcOEt), due to its relatively weak adsorption behavior for EtOH rather than AcOH.

Published
2021

7. Reversible MOF-Based Sensors for the Electrical Detection of Iodine Gas

Author

Karena W. Chapman, Martin Schröder, Ryan C. Hill, James L. Krumhansl, Xinran Zhang, Zhihengyu Chen, Mara E. Schindelholz, Tina M. Nenoff, Sihai Yang, and Leo J. Small

Subjects
impedance spectroscopy, Materials science, metal−organic framework, Nanoporous, iodine, Radioactive waste, chemistry.chemical_element, Nanotechnology, 02 engineering and technology, nanoporous, 010402 general chemistry, 021001 nanoscience & nanotechnology, Iodine, 01 natural sciences, Durability, 0104 chemical sciences, Dielectric spectroscopy, First responder, chemistry, sensor, General Materials Science, Metal-organic framework, 0210 nano-technology, Research Article, MOF
Abstract

Iodine detection is crucial for nuclear waste clean-up and first responder activities. For ease of use and durability of response, robust active materials that enable the direct electrical detection of I2 are needed. Herein, a large reversible electrical response is demonstrated as I2 is controllably and repeatedly adsorbed and desorbed from a series of metal–organic frameworks (MOFs) MFM-300(X), each possessing a different metal center (X = Al, Fe, In, or Sc) bridged by biphenyl-3,3′,5,5′-tetracarboxylate linkers. Impedance spectroscopy is used to evaluate how the different metal centers influence the electrical response upon cycling of I2 gas, ranging from 10× to 106× decrease in resistance upon I2 adsorption in air. This large variation in electrical response is attributed not only to the differing structural characteristics of the MOFs but also to the differing MOF morphologies and how this influences the degree of reversibility of I2 adsorption. Interestingly, MFM-300(Al) and MFM-300(In) displayed the largest changes in resistance (up to 106×) yet lost much of their adsorption capacity after five I2 adsorption cycles in air. On the other hand, MFM-300(Fe) and MFM-300(Sc) revealed more moderate changes in resistance (10–100×), maintaining most of their original adsorption capacity after five cycles. This work demonstrates how changes in MOFs can profoundly affect the magnitude and reversibility of the electrical response of sensor materials. Tuning both the intrinsic (resistivity and adsorption capacity) and extrinsic (surface area and particle morphology) properties is necessary to develop highly reversible, large signal-generating MOF materials for direct electrical readout for I2 sensing.

Published
2019

8. Photocatalytic Hydrogen Generation from a Visible-Light-Responsive Metal–Organic Framework System: Stability versus Activity of Molybdenum Sulfide Cocatalysts

Author

Bardiya Valizadeh, Ophélie Marie Planes, Stavroula Kampouri, Kyriakos C. Stylianou, Andreas Züttel, Tu N. Nguyen, Daniele Ongari, Berend Smit, and Wen Luo

Subjects
Materials science, metal−organic framework, Hydrogen, chemistry.chemical_element, Nanoparticle, 02 engineering and technology, 010402 general chemistry, Photochemistry, 01 natural sciences, 7. Clean energy, Catalysis, Electron transfer, Engineering, Affordable and Clean Energy, molybdenum sulfide, General Materials Science, Nanoscience & Nanotechnology, visible light, Hydrogen production, metal-organic framework, 021001 nanoscience & nanotechnology, 0104 chemical sciences, chemistry, hydrogen, Chemical Sciences, Photocatalysis, Water splitting, Metal-organic framework, 0210 nano-technology, photocatalysis
Abstract

We report the use of two earth abundant molybdenum sulfide-based cocatalysts, Mo3S132- clusters and 1T-MoS2 nanoparticles (NPs), in combination with the visible-light active metal-organic framework (MOF) MIL-125-NH2 for the photocatalytic generation of hydrogen (H2) from water splitting. Upon irradiation (λ ≥ 420 nm), the best-performing mixtures of Mo3S132-/MIL-125-NH2 and 1T-MoS2/MIL-125-NH2 exhibit high catalytic activity, producing H2 with evolution rates of 2094 and 1454 μmol h-1 gMOF-1 and apparent quantum yields of 11.0 and 5.8% at 450 nm, respectively, which are among the highest values reported to date for visible-light-driven photocatalysis with MOFs. The high performance of Mo3S132- can be attributed to the good contact between these clusters and the MOF and the large number of catalytically active sites, while the high activity of 1T-MoS2 NPs is due to their high electrical conductivity leading to fast electron transfer processes. Recycling experiments revealed that although the Mo3S132-/MIL-125-NH2 slowly loses its activity, the 1T-MoS2/MIL-125-NH2 retains its activity for at least 72 h. This work indicates that earth-abundant compounds can be stable and highly catalytically active for photocatalytic water splitting, and should be considered as promising cocatalysts with new MOFs besides the traditional noble metal NPs.

Published
2018
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