Nanoporous Metal-organic Framework Research Articles

Nanoporous Metal–Organic Framework Based on Furan-2,5-Dicarboxylic Acid with High Potential in Selective Adsorption and Separation of Gas Mixtures

Nanoporous Metal–Organic Framework Based on Furan-2,5-Dicarboxylic Acid with High Potential in Selective Adsorption and Separation of Gas Mixtures

Structure optimization of ceramic-based metal−organic framework membrane for efficient desalination

To address global water pollution and crisis issue, wastewater recycling, seawater and brackish water desalination have been increasingly utilized to produce clean water. Ceramic membranes have been gaining widespread interest due to their unique physicochemical properties and high stability. Integrating nanoporous MOF (metal organic framework) with ceramic membranes could enable a rational design of ceramic-based MOF membranes with enhance sieving performance. Herein, we report an in-situ method to construct an inter-crystalline defect-free MOF layer on ZrO2 ceramic membranes for efficient desalination application. After optimizing synthesis parameters, an inter-crystalline defect-free and well-intergrown ceramic-based MOF membrane was obtained. The ceramic-based MOF membranes not only demonstrated a near-complete salt rejection, but also exhibited high water flux, which are superior to most of the reported zeolite and MOF membranes. In addition, the MOF membranes exhibited promising performance and structure stability even when exposed to harsh water environments. Our work introduces a protocol for the design of high-performance ceramic-based MOF membrane as a promising candidate for challenging desalination applications under different environments.

Iron-Based nanoporous Metal-Organic frameworks with Side-Chain amino substituents for Efficiency-Regulated oxygen evolution reaction

Nanoporous iron-based MOFs, possessing notable attributes such as adjustable structure, considerable porosity, and large surface area, exhibit considerable promise for various applications in the field of photocatalysis. However, the effect of the ligand substitution ratio on the photocatalytic reaction process is currently unknown. In the current investigation, a series of iron-based MOFs MIL-101(Fe)-X with various ratios of amino substituents (X = H: NH2 = 1:0, 1:0.5, 1:1, 1:2, 1:4, 0:1) were synthesized using the solvothermal method. The morphology and structure were characterized using SEM, TEM, XRD, XPS, BET, FT-IR, etc. Their efficacy as water oxidation catalysts under AM1.5G (solar light) irradiation was investigated. The findings of the study indicated that MIL-101(Fe) with an X value of 1:2 exhibited the highest surface area of 380.4 m2/g. This resulted in the exposure of a greater number of active sites, leading to enhanced charge separation efficiency and exceptional oxygen evolution activity when illuminated by simulated sunlight. The oxygen evolution rate under solar light was measured to be 11.7 mmol·h−1·g−1. This research confirmed the effect of substituent variation on the oxygen evolution rate by modulating the substitution ratio of side-chain ligands on MOFs, thereby altering their microstructure and charge distribution. The incorporation of a suitable quantity of amino groups, that act as strong electron-donating groups, facilitated the effective separation of electron-hole pairs generated during the photocatalytic process. However, an excessive introduction of amino groups can result in a reduction in both pore structure and surface area, thereby impeding the efficiency of the photocatalytic oxygen evolution reaction.

Cerium-Based Nanoporous Metal–Organic Frameworks Incorporated with Different Metals for the Remediation of Fluoride Ions from Water

Cerium-Based Nanoporous Metal–Organic Frameworks Incorporated with Different Metals for the Remediation of Fluoride Ions from Water

Photoswitchable Radical State in Nanoporous Metal-Organic Framework Films with Embedded Hexaarylbiimidazole.

Photoresponsive materials enable dynamic remote control of their fundamental properties. The incorporation of photochromic molecules in nanoporous metal-organic frameworks (MOFs) provides a unique opportunity to tailor the material properties, including the interaction between the MOF host and guest molecules in the pores. Here, a MOF film of type HKUST-1 with embedded hexaarylbiimidazole (HABI), undergoing reversible light-induced reactions between the stable dimer state and the metastable radical state, is presented. The switching between the dimer and radical form is shown by infrared, UV-vis, and electron paramagnetic resonance (EPR) spectroscopy. By transient uptake experiments with ethanol and methanol as probe molecules, we show that the dimer-radical switching impacts the host-guest interaction and, in particular, modifies the uptake amount and diffusion coefficient of the guest molecules. For ethanol, the diffusion slows down by 75%. This research presents the first MOF material with photoswitchable (meta)stable dimer and radical molecules, and it contributes to the advancement of photoresponsive nanoporous materials.

Solvent-Directed Construction of a Nanoporous Metal-Organic Framework with Potential in Selective Adsorption and Separation of Gas Mixtures Studied by Grand Canonical Monte Carlo Simulations.

In this report, a microporous metal-organic framework of [Ca(TDC)(DMA)]n (1) and a two-dimensional coordination polymer of [Ca(TDC)(DMF)2 ]n (2), (TDC2- =Thiophene-2,5-dicarboxylate, DMA=N, N'-dimethylacetamide and DMF=N, N'-dimethylformamide) based on Ca(II) were designed by the effect of solvent, and X-ray analysis was performed for the single crystals of 1 and 2. Then, compound 1 was synthesized in three different methods and identified with a set of analyses. Compared to other adsorbents, MOFs are widely used in the field of adsorption and separation of various gases due to a series of distinctive features such as diverse and adjustable structures pores with different dimensions, high porosity and surface area with regular distribution of active sites. Therefore, the ability of 1 to uptake single gases (CH4 , CO2 , C2 H2 , H2, and N2 ) and separation of several binary mixtures of gases (CO2 /CH4 , CO2 /N2 , CO2 /H2 and CO2 /C2 H2 ), were investigated using Grand Canonical Monte Carlo simulations. Volumetric and gravimetric adsorption isotherms in various operating conditions, the isosteric heat of adsorption (qst ), the chemical potential for each thermodynamic state, and snapshots during the simulation process were reported in all cases. The results obtained from the adsorption simulation indicate that compound 1 has a high capacity for uptake of H2 (16 mmol g-1 ) and N2 (12.5 mmol g-1 ), CO2 (6.6 mmol g-1 ), C2 H2 (5 mmol g-1 ) and CH4 (1.5 mmol g-1 ) gases at 1 bar. It also performs well in separating CO2 in binary mixtures, which can be attributed to the presence of open metal sites in nodes of 1 and their electrostatic tendency to interact with CO2 containing the higher quadrupole dipole moment compared to other components of the mixture.

Surface-Degenerate Semiconductor Photocatalysis for Efficient Water Splitting without Sacrificial Agents via a Reticular Chemistry Approach.

The production of green hydrogen through photocatalytic water splitting is crucial for a sustainable hydrogen economy and chemical manufacturing. However, current approaches suffer from slow hydrogen production (<70 µmol·gcat-1·h-1) due to the sluggish four-electrons oxygen evolution reaction (OER) and limited catalyst activity. Herein, we achieve efficient photocatalytic water splitting by exploiting a multifunctional interface between a nano-photocatalyst and metal-organic framework (MOF) layer. The functional interface plays two critical roles: (1) enriching electron density directly on photocatalyst surface to promote catalytic activity, and (2) delocalizing photogenerated holes into MOF to enhance OER. Our photocatalytic ensemble boosts hydrogen evolution by ~100-fold over pristine photocatalyst and concurrently produces oxygen at ideal stoichiometric ratio, even without using sacrificial agents. Notably, this unique design attains superior hydrogen production (519 µmol·gcat-1·h-1) and apparent quantum efficiency up to 13-fold and 8-fold better than emerging photocatalytic designs utilizing hole scavengers. Comprehensive investigations underscore the vital role of the interfacial design in generating high-energy photoelectrons on surface-degenerate photocatalyst to thermodynamically drive hydrogen evolution, while leveraging the nanoporous MOF scaffold as an effective photohole sink to enhance OER. Our interfacial approach creates vast opportunities for designing next-generation, multifunctional photocatalytic ensembles using reticular chemistry with diverse energy and environmental applications.

Surface‐Degenerate Semiconductor Photocatalysis for Efficient Water Splitting without Sacrificial Agents via a Reticular Chemistry Approach

AbstractThe production of green hydrogen through photocatalytic water splitting is crucial for a sustainable hydrogen economy and chemical manufacturing. However, current approaches suffer from slow hydrogen production (&lt;70 μmol ⋅ gcat−1 ⋅ h−1) due to the sluggish four‐electrons oxygen evolution reaction (OER) and limited catalyst activity. Herein, we achieve efficient photocatalytic water splitting by exploiting a multifunctional interface between a nano‐photocatalyst and metal–organic framework (MOF) layer. The functional interface plays two critical roles: (1) enriching electron density directly on photocatalyst surface to promote catalytic activity, and (2) delocalizing photogenerated holes into MOF to enhance OER. Our photocatalytic ensemble boosts hydrogen evolution by ≈100‐fold over pristine photocatalyst and concurrently produces oxygen at ideal stoichiometric ratio, even without using sacrificial agents. Notably, this unique design attains superior hydrogen production (519 μmol ⋅ gcat−1 ⋅ h−1) and apparent quantum efficiency up to 13‐fold and 8‐fold better than emerging photocatalytic designs utilizing hole scavengers. Comprehensive investigations underscore the vital role of the interfacial design in generating high‐energy photoelectrons on surface‐degenerate photocatalyst to thermodynamically drive hydrogen evolution, while leveraging the nanoporous MOF scaffold as an effective photohole sink to enhance OER. Our interfacial approach creates vast opportunities for designing next‐generation, multifunctional photocatalytic ensembles using reticular chemistry with diverse energy and environmental applications.

Self‐Assembled Nanoporous Metal–Organic Framework Monolayer Film for Osmotic Energy Harvesting

AbstractOsmotic energy represents a promising energy resource because it is sustainable and environmentally benign. Subnanoscale channels are considered as a competitive platform for generating this blue energy due to their highly selective and ultrafast ion transport. However, fabricating functional subnanochannels capable of high energy output remains challenging. Here, a heterogeneous subnanochannel membrane formed by coating a functionalized self‐assembled metal−organic framework (MOF) monolayer (SAMM) film on a porous anodic aluminum oxide membrane, is reported. The SAMM film, with a thickness of ≈160 nm, is fabricated by self‐assembly of poly(methyl methacrylate‐co‐vinylimidazole)‐modified UiO‐66‐NH2 nanoparticles at the water−air interface. In the SAMM, imidazole and NH2 groups provide abundant positive charges, while the angstrom‐scale windows act as ionic filters for selective screening of anions with different hydration diameters. As a result, the heterogeneous membrane exhibits excellent capacity for anion‐selective transport, which contributes to an optimal osmotic power of 6.76 W m−2 under a 100‐fold NaCl gradient, as well as a high Cl−/SO42− selectivity of ≈42.2. Further, the output power is increased to 10.5 W m−2 by methylating imidazole moieties on the MOF surface. This work provides a facile and modular approach to fabricate subnanochannels for enabling highly selective and efficient osmotic energy conversion.

Spiropyran-Decorated Nanoporous Metal–Organic Frameworks for Reversible Light-Controlled Adsorption of Multiple Salts from Water: Implications for Water Purification

Spiropyran-Decorated Nanoporous Metal–Organic Frameworks for Reversible Light-Controlled Adsorption of Multiple Salts from Water: Implications for Water Purification

MOF@Polydopamine-incorporated membrane with high permeability and mechanical property for efficient fouling-resistant and oil/water separation

Metal organic frameworks (MOFs) have demonstrated great potential for their favorable impacts on the performance of water treatment membranes. Herein, the novel nanoparticles based on both nanoporous MOFs and organic PDA layer was exploited as a novel dopant for the fabrication of PES ultrafiltration (UF) membranes. The PDA was synthesized via oxidative self-polymerization under alkaline conditions and formed adhesive coatings on dispersed MOF. The properties of resulting membranes on the porosity, membrane morphology, hydrophilicity, permeability and anti-fouling performance were adequately investigated. The membranes incorporated with MOF@PDA exhibited exceptionally high permeability (209.02 L m−2·h−1), which is approximately 6 times higher than that of the pure PES membrane, and high BSA rejection (99.12%). Notably, the mechanical property and hydrophilicity of the PES membrane were both enhanced by MOF@PDA, and it has been demonstrated that greater hydrophilicity prevents fouling under practical conditions, which results in significant improvements in flux recovery ratio (FRR) (82%). In addition, the modified PES membranes were used to purify the oil/water emulsion, and the results indicates that the membranes have high permeability and rejection of oil/water emulsion, showing its great promise in practical oily sewage remediation.

Sorption Thermal Energy Storage Performance of Nanoporous Metal–Organic Frameworks and Covalent Organic Frameworks by Grand Canonical Monte Carlo Simulations

Sorption Thermal Energy Storage Performance of Nanoporous Metal–Organic Frameworks and Covalent Organic Frameworks by Grand Canonical Monte Carlo Simulations

End-to-end AI framework for interpretable prediction of molecular and crystal properties

We introduce an end-to-end computational framework that allows for hyperparameter optimization using the DeepHyper library, accelerated model training, and interpretable AI inference. The framework is based on state-of-the-art AI models including CGCNN, PhysNet, SchNet, MPNN, MPNN-transformer, and TorchMD-NET. We employ these AI models along with the benchmark QM9, hMOF, and MD17 datasets to showcase how the models can predict user-specified material properties within modern computing environments. We demonstrate transferable applications in the modeling of small molecules, inorganic crystals and nanoporous metal organic frameworks with a unified, standalone framework. We have deployed and tested this framework in the ThetaGPU supercomputer at the Argonne Leadership Computing Facility, and in the Delta supercomputer at the National Center for Supercomputing Applications to provide researchers with modern tools to conduct accelerated AI-driven discovery in leadership-class computing environments. We release these digital assets as open source scientific software in GitLab, and ready-to-use Jupyter notebooks in Google Colab.

Polypyrrole‐boosted photothermal energy storage in MOF‐based phase change materials

AbstractInfiltrating phase change materials (PCMs) into nanoporous metal–organic frameworks (MOFs) is accepted as a cutting‐edge thermal energy storage concept. However, weak photon capture capability of pristine MOF‐based composite PCMs is a stumbling block in solar energy utilization. Towards this goal, we prepared advanced high‐performance pristine MOF‐based photothermal composite PCMs by simultaneously integrating photon absorber guest (polypyrrole [PPy]) and thermal storage guest (1‐octadecanol [ODA]) into an MOF host (Cr‐MIL‐101‐NH2). The coated PPy layer on the surface of ODA@MOF not only serves as a photon harvester, but also serves as a phonon enhancer. Resultantly, ODA@MOF/PPy composite PCMs exhibit intense and broadband light absorption characteristic in the ultraviolet–visible–near‐infrared region, and higher heat transfer ability than ODA@MOF. Importantly, the photothermal conversion and storage efficiency of ODA@MOF/PPy‐6% is up to 88.3%. Additionally, our developed MOF‐based photothermal composite PCMs also exhibit long‐standing antileakage stability, energy storage stability, and photothermal conversion stability. The proposed coating strategy and in‐depth understanding mechanism are expected to facilitate the development of high‐efficiency MOF‐based photothermal composite PCMs in solar energy utilization.

Sensing of KCl, NaCl, and Pyocyanin with a MOF-Decorated Electrospun Nitrocellulose Matrix

Wearable sensors can provide important insight into a patient’s health status by monitoring the concentration of specific biomarkers in body fluids. Compared to biofluids such as blood or cerebrospinal fluid, which require an invasive acquisition process, other body fluids such as sweat or exhaled air can be easily collected using patches or masks, sufficient for the detection of metabolic and pathological changes. However, the successful integration of an efficient biosensor into textiles or polymer substrates is a challenge if flexibility and functionality are not to be compromised. Here, we demonstrate the integration of nanoporous metal–organic framework (MOF) particles with nitrocellulose (NC) fibrous layers using an electrospinning approach and validate the efficiency of our MOF@NC structure as biosensors. The chemical response of this hybrid nanomaterial upon exposure to different ionic sweat biomarkers such as NaCl and KCl as well as pyocyanin, a biomarker for the nosocomial pathogen Pseudomonas aeruginosa, was investigated using Raman spectroscopy. A change of the Raman intensity at distinct peaks of our MOF-containing architecture occurs after treatment of the material with the analyte solutions. Furthermore, we observed the sensitivities for pyocyanin at the normalized Raman intensity change to be up to −1120 au μm–1, about 4 orders of magnitude larger than for NaCl and KCl. The independence of our architecture from the type of MOF and the possibility of using different MOFs with individual chemistry make this approach a promising platform for versatile and adaptable sensing of biomarkers with high sensitivity and selectivity.

Nanoporous Metal-Organic Framework Thin Films Prepared Directly from Gaseous Precursors by Atomic and Molecular Layer Deposition: Implications for Microelectronics.

Atomic/molecular layer deposition (ALD/MLD) allows for the direct gas-phase synthesis of crystalline metal-organic framework (MOF) thin films. Here, we show for the first time using krypton and methanol physisorption measurements that ALD/MLD-fabricated copper 1,4-benzenedicarboxylate (Cu-BDC) ultrathin films possess accessible porosity matching that of the corresponding bulk MOF.

A Two-Way Rod-Packing Indium-Based Nanoporous Metal–Organic Framework for Effective C2/C1 and C2/CO2 Separation

The exploration of reticular chemistry pertaining to rod-packing metal–organic frameworks and the development of solid adsorbents for multitask hydrocarbon separations are two active topics of current research. In this study, an In-organic coordination framework compound denoted ZJNU-121 was assembled from a custom-designed bithiophene-functionalized tetracarboxylate ligand. The title compound not only exhibited a rare two-way rod-packing pattern but also displayed the impressive capability of capturing C2 hydrocarbons from CH4 and CO2 to achieve C2/C1 and C2/CO2 separations. Under ambient conditions, the ideal adsorbed solution theory-predicted adsorption selectivities for equimolar mixtures fall in the range of 8.4–13.8 (C2Hn/CH4) and 2.3–3.4 (C2Hn/CO2). Such separation potentials were also ascertained by the column breakthrough experiments. Furthermore, the in-depth theoretical insight unveiled the crucial role of active sites such as thiophene sulfur, carboxylate oxygen, and the bridging μ2-OH group in capturing C2 hydrocarbons in preference to CO2 and CH4. Additionally, the structural integrity of ZJNU-121 can be retained in aqueous solutions with pH values varying from 3 to 11 for 24 h at ambient temperature, as verified by the preservation of PXRD patterns, textural characteristics, and static/dynamic adsorption behaviors. This research not only enriched the architectural diversity of rod MOFs but also reported a robust adsorbent with good application prospects for diversified hydrocarbon separations.

Polydopamine-coated metal-organic framework-based composite phase change materials for photothermal conversion and storage

The liquid leakage and weak solar absorption capacity of organic phase change materials (PCMs) seriously hinder the efficient utilization of solar energy and thermal energy storage. To address these issues, we prepared nanoporous metal organic framework (Ni-MOF) for the vacuum infiltration of paraffin wax (PW), followed by the coating of solar-absorbing functional polydopamine (PDA) on the surface of PW@MOF for photothermal conversion and storage. As an efficient photon harvester, PDA coating endows PW@MOF/PDA composite PCMs with excellent photothermal conversion and storage properties due to the robust broadband solar absorption capability in the UV–vis region. Resultantly, our prepared PW@MOF/PDA composite PCMs exhibit a high photothermal conversion and storage efficiency of 91.2%, while that of PW@MOF composite PCMs is only zero. In addition, PW@MOF/PDA composite PCMs also exhibit excellent thermal stability, shape stability, energy storage stability, and photothermal conversion stability. More importantly, this coating strategy is universal by integrating different MOFs and solar absorbers, showing the potential to accelerate the major breakthroughs of high-efficiency MOF-based photothermal composite PCMs in solar energy utilization.

Nanochannel-Based Heterometallic {CoIITbIII}-Organic Framework for Fluorescence Recognition of Tryptophan and Catalytic Cycloaddition of Epoxides with CO2

To pave the way for the salient application of metal–organic frameworks (MOFs) as realistic sensors, it is critical to screen or design the customized functional structure with specified prominent synergistic effects provided by its constituents, voids, specific surfaces, functional sites, etc. This prompts us to study the sensing performance of a honeycomb nanochannel of heterometallic MOFs previously invented. This structure has excellent physical and chemical properties of high specific surface area, good chemical stability, and highly open coexistence of Lewis acid–base sites. In this work, the highly robust sky-blue [CoTb(CO2)6(OH2)]-based heterometallic framework of {[(CH3)2NH2][CoTb(TDP)(H2O)]·3H2O·4DMF}n (NUC-31; H6TDP = 2,4,6-tri(2′,4′-dicarboxyphenyl)pyridine) was synthesized. The results of the fluorescence recognition experiment show that, compared with other amino acids, NUC-31 has an ultrastrong fluorescence quenching for tryptophan with a detection limit as low as 0.11 mM, which means that NUC-31 can be used as a potential fluorescence probe for the targeted detection of tryptophan of ecosystems. In addition, the catalytic experiment results indicated that NUC-31 has high activity for catalyzing the cycloaddition reaction of epoxides with CO2 under 75 °C and 1 atm. It is precisely due to NUC-31 having extremely unsaturated tetracoordinated Co(II) and hepta-coordinated Tb(III) metal ions as well as a high pore volume (65.1%), which makes the catalytic reaction conditions relatively mild. Therefore, this work certificated that nanoporous MOFs assembled from a multifunctional ligand with the highly open coexistent Lewis acid–base sites had a potential application not only in monitoring tryptophan in clinical scenarios but also as an effective heterogeneous catalyst.

Three-Dimensional Lanthanide-Based Nanoporous Metal–Organic Frameworks for High-Performance Supercapacitors

Lanthanides have been proved to be unprecedented when it comes to organized nanoporous materials with high coordination environment. In the quest to enhance the applications for energy-storage materials, three lanthanide-based metal–organic frameworks (MOFs) have been synthesized by facile hydrothermal conditions using 5-nitroisophthalic acid (H2L) as a ligand, namely, Ce–H2L, Sm–H2L, and Eu–H2L. These nanoporous MOFs consist of nine coordination sites around the lanthanide metal ion giving rise to distorted monocapped square antiprism geometry and 3D crystal structures. The electrochemical measurements demonstrate that charge storage in these MOFs occurs through faradaic redox reactions. The charge–discharge studies show that these nanoporous MOF materials deliver high specific capacity. Ce–H2L, Sm–H2L, and Eu–H2L deliver specific capacities of 625, 356, and 252 C g–1 (1389, 791, and 560 F g–1), respectively, at a current density of 1 A g–1. A symmetric supercapacitor Swagelok device has been fabricated using Ce–H2L as an electrode to further demonstrate the advantage of as-synthesized MOF. The developed symmetric supercapacitor gives a maximum specific energy of 13.6 Wh kg–1 and a maximum specific power of 7110 W kg–1 in the voltage window of 1.425 V. The energy storage trend in these nanoporous materials is Ce–H2L > Sm–H2L > Eu–H2L, which is further supported by the DFT calculations.