ResponZIF Structures: Zeolitic Imidazolate Frameworks as Stimuli-Responsive Materials

ACS Applied Materials & Interfaces, Journal Year: 2021, Volume and Issue: 13(43), P. 50602 - 50642

Published: Oct. 20, 2021

Zeolitic imidazolate frameworks (ZIFs) have long been recognized as a prominent subset of the metal-organic framework (MOF) family, in part because their ease synthesis and good thermal chemical stability, alongside attractive properties for diverse potential applications. Prototypical ZIFs like ZIF-8 become embodiments significant promise held by porous coordination polymers next-generation designer materials. At same time, intriguing property experiencing structural changes upon application external stimuli such temperature, mechanical pressure, guest adsorption, or electromagnetic fields, among others, has placed this family MOFs squarely under umbrella stimuli-responsive In review, we provide an overview current understanding triggered electronic responses observed (linker bond dynamics, crystalline amorphous phase changes, luminescence, etc.). We then describe state-of-the-art experimental computational methodology capable shedding light on these complex phenomena, followed comprehensive summary nature four prototypical ZIFs: ZIF-8, ZIF-7, ZIF-4, ZIF-zni. further expose relevant challenges characterization fundamental responsive ZIFs, including how to take advantage flexible new avenues.

Language: Английский

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Insights into Mass Transfer Barriers in Metal–Organic Frameworks

Chemistry of Materials, Journal Year: 2022, Volume and Issue: 34(9), P. 4134 - 4141

Published: April 29, 2022

Identifying mass transfer limitations is imperative for the practical application of nanoporous solids in adsorptive separations and catalysis. In particular, metal–organic frameworks (MOFs) with a staggering assortment unique pore architectures chemical binding sites are one class materials where understanding structure–property relationships can facilitate material design. Here, we performed volumetric physisorption measurements collected n-hexane adsorption isotherms nine Zr-MOFs architectures, textural properties, crystal sizes. We on commercially available instrument used generalized model that includes intracrystalline diffusion as well possible resistance at boundary. The results indicate uptake rates all MOFs considered here limited by through crystallite surfaces. Moreover, severity guest concentration dependence these surface resistances differ each MOF. identification permeability rate-limiting process within will aid design next-generation adsorbents catalysts.

Language: Английский

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Prediction of the Diffusion Coefficient through Machine Learning Based on Transition-State Theory Descriptors

The Journal of Physical Chemistry C, Journal Year: 2024, Volume and Issue: 128(16), P. 6917 - 6926

Published: April 10, 2024

Nanoporous materials serve as very effective media for storing and separating small molecules. To design the best a given application based on adsorption, one usually assesses equilibrium performance by using key thermodynamic quantities such Henry constants or adsorption loading values. go beyond standard methodologies, we probe here transport effects occurring in material studying self-diffusion coefficients of xenon inside nanopores framework materials. We find good correlations between diffusion pore aperture size well other geometrical energetic descriptors. used extensive molecular dynamics simulations to calculate coefficient 4873 MOFs from CoRE MOF 2019 database, first large-scale database properties published at this scale. Based these data, present tool quickly evaluate energy barrier that proved be correlated rate. This descriptor, alongside characterizations, was then build machine learning model can predict MOFs. The final trained is quite accurate shows root-mean-square error log10 equal 0.25.

Language: Английский

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Mind the Gap: The Role of Mass Transfer in Shaped Nanoporous Adsorbents for Carbon Dioxide Capture

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(34), P. 23633 - 23648

Published: Aug. 20, 2024

Adsorptive separations by nanoporous materials are major industrial processes. The importance of solid adsorbents is only expected to grow due the increased focus on carbon dioxide capture technology and energy-efficient separations. To evaluate performance an adsorbent design a separation process, adsorption thermodynamics kinetics must be known. However, although diffusion determine maximum production rate in any adsorption-based separation, this aspect has received less attention challenges associated with conducting measurements. These exacerbated study shaped presence porosity at different length scales. As result, selection typically relies mainly properties equilibrium, i.e., uptake capacity, selectivity enthalpy. In Perspective, based extensive literature review mass transfer CO2 adsorbents, we discuss limitations measuring materials, from powder form bed, considering nature equilibrium-based or kinetic-based By highlighting lack discrepancies between published diffusivity data context capture, future opportunities studying across scales

Language: Английский

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Free volume theory of self-diffusion in zeolites: Molecular simulation and experiment

Microporous and Mesoporous Materials, Journal Year: 2024, Volume and Issue: 381, P. 113305 - 113305

Published: Aug. 23, 2024

Language: Английский

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Diffusion in nanoporous materials with special consideration of the measurement of determining parameters (IUPAC Technical Report)

Pure and Applied Chemistry, Journal Year: 2024, Volume and Issue: 97(1), P. 1 - 89

Published: Nov. 19, 2024

Abstract The random motion (the diffusion) of guest molecules in nanoporous host materials is key to their manifold technological applications and, simultaneously, a ubiquitous phenomenon nature quite general. Based on specification the different conditions under which molecular diffusion may occur and thus resulting relevant parameters, survey various ways measurement determining parameters given. Starting with condensed introduction respective measuring principles, notably includes summary accessible by each individual technique, jointly an overview strengths weaknesses as well ranges observation. presentation complemented basic relations theory modeling materials, illustrating significance for enhancing informative value technique added attainable combination. By providing guidelines reporting properties chemical compounds nanopores, document aims contribute clarification standardization presentation, nomenclature, methodology associated documentation phenomena serving catalytic, mass separation, other purposes.

Language: Английский

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Enhanced Adsorption and Mass Transfer of Hierarchically Porous Zr-MOF Nanoarchitectures toward Toxic Chemical Removal

ACS Applied Materials & Interfaces, Journal Year: 2021, Volume and Issue: 13(49), P. 58848 - 58861

Published: Dec. 2, 2021

Zirconium-based metal-organic frameworks (Zr-MOFs) have shown tremendous prospects as highly efficient adsorbents against toxic chemicals under ambient conditions. Here, we report for the first time enhanced chemical adsorption and mass transfer properties of hierarchically porous Zr-MOF nanoarchitectures. A general scalable sol-gel-based strategy combined with facile pressure drying (APD) was utilized to construct MOF-808, MOF-808-NH2, UiO-66-NH2 xerogel monoliths, denoted G808, G808-NH2, G66-NH2, respectively. The resulting xerogels demonstrated 3D networks assembled by nanocrystal aggregates, substantially higher mesoporosities than precipitate analogues. Microbreakthrough tests on powders tube breakthrough experiments engineered granules were conducted at different relative humidities comprehensively evaluate NO2 capabilities. showed considerably better removal abilities precipitates, whether intrinsically or simulated respirator canister/protection filter environment Multiple physicochemical characterizations illuminate filtration mechanisms. Analysis kinetics patterns in further performed visualize underlying structure-activity relationship using gravimetric uptake zero length column methods cyclohexane acetaldehyde probes. results revealed that synergy hierarchical porosities nanosized crystals could effectively expedite intracrystalline diffusion G66-NH2 well alleviate surface resistance G808-NH2 xerogel, which led accelerated overall thus performance toward removal.

Language: Английский

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Effects of MOF linker rotation and functionalization on methane uptake and diffusion

Molecular Systems Design & Engineering, Journal Year: 2023, Volume and Issue: 8(4), P. 527 - 537

Published: Jan. 1, 2023

Neglecting linker rotation in molecular simulations of methane UiO-66 can have a significant impact on diffusion and moderate uptake.

Language: Английский

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Multiphase modeling of pressure-dependent hydrogen diffusivity in fractal porous structures of acrylonitrile butadiene rubber-carbon black composites with different fillers

Polymer, Journal Year: 2024, Volume and Issue: 311, P. 127552 - 127552

Published: Aug. 28, 2024

Language: Английский

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On De Gennes narrowing of fluids confined at the molecular scale in nanoporous materials

The Journal of Chemical Physics, Journal Year: 2024, Volume and Issue: 160(2)

Published: Jan. 9, 2024

Beyond well-documented confinement and surface effects arising from the large internal severely confining porosity of nanoporous hosts, transport nanoconfined fluids remains puzzling in many aspects. With striking examples such as memory, i.e., non-viscous effects, intermittent dynamics, barriers, dynamics nanoconfinement challenge classical formalisms (e.g., random walk, viscous/advective transport)—especially for molecular pore sizes. In this context, while frameworks Brownian motion, free volume theory, diffusion are available to describe self-diffusion a molecularly confined fluid, microscopic theory collective (i.e., permeability), which characterizes flow induced by thermodynamic gradient, is lacking. Here, fill knowledge gap, we invoke concept “De Gennes narrowing,” relates wavevector-dependent diffusivity D0(q) fluid structure factor S(q). First, using simulation simple yet representative prototypical solid (zeolite), unravel an essential coupling between structural ordering imposed on crystalline host. Second, despite complex interplay with marked Bragg peaks structure, shown be accurately described through De narrowing. Moreover, contrast bulk departure narrowing macroscopic limit small fluid/solid interactions severe screen and, hence, weaken wavevector dependence transport.

Language: Английский

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