Metal-organic Frameworks Research Articles

Nanoconfined heterogeneous catalysis triggered by copper oxide supported metal–organic framework UiO-66-NH2/peroxymonosulfate for rapidly removing bisphenol A in water

Nanoconfined heterogeneous catalysis triggered by copper oxide supported metal–organic framework UiO-66-NH2/peroxymonosulfate for rapidly removing bisphenol A in water

Synthesis and utilization of mixed-metal (Zn/Cd) metal–organic frameworks for ultra-trace determination of diazinon and ethion via ion mobility spectrometry

Synthesis and utilization of mixed-metal (Zn/Cd) metal–organic frameworks for ultra-trace determination of diazinon and ethion via ion mobility spectrometry

Fluorescence sensor array for highly sensitive pattern recognition of biothiols in food based on tricolor upconversion luminescence metal-organic frameworks

Fluorescence sensor array for highly sensitive pattern recognition of biothiols in food based on tricolor upconversion luminescence metal-organic frameworks

3D‐Printed In Situ Growth of Bilayer MOF Hydrogels for Accelerated Osteochondral Defect Repair

AbstractRepairing osteochondral (OC) defect presents a significant challenge due to the intricate structural requirements and the unpredictable differentiation pathways of bone marrow mesenchymal stem cells (BMSCs). To address this challenge, a novel biomimetic OC hydrogel scaffold is developed that features a structure of soft and hard components. This scaffold incorporates bilayer metal–organic frameworks (MOFs), specifically ZIF‐67 in the upper layer and ZIF‐8 in the lower layer, achieved through an in situ printing process. This configuration enables the spatial and temporal modulation of BMSC differentiation by controlling the release of Co2⁺ and Zn2⁺. The results demonstrate that the bilayer MOF hydrogels significantly outperform hydrogels that either lack MOFs or contain a single type of MOF in enhancing repair outcomes in rabbit models of knee OC defects. The improved regenerative efficacy is attributed to the distinct chondrogenic and osteogenic differentiation cues provided by the bilayer MOFs, effectively guiding BMSCs toward enhanced tissue regeneration. This customizable biomimetic OC hydrogel scaffold not only opens new avenues for innovative therapeutic strategies but also holds great promise for widespread clinical applications.

Non‐selective Defect Minimization towards Highly Efficient Metal‐Organic Framework Membranes for Gas Separation

The persistence of defects in polycrystalline membranes poses a substantial obstacle to reaching the theoretical molecular sieving separation and scaling up production. The low membrane selectivity in most reported literature is largely due to the unavoidable non‐selective defects during synthesis, leading to a mismatch between the well‐defined pore structure of polycrystalline molecular sieve materials. This paper presents a novel approach for minimizing non‐selective defects in metal‐organic framework (MOF) membranes by a constricted crystal growth strategy in a confined environment. The in‐situ ZIF formation using the densely packed seeding array between the substrate and the pre‐grown top ZIF layer yields a confined membrane interlayer, which is highly uniform with a tightly packed crystalline structure. Unlike uncontrolled crystal growth, we purposely regulate the interlayer membrane growth in the direction parallel to the substrate. A notable 99% decrease in defects in the confined interlayer was achieved compared to the random‐grown top layer, leading to a ~353% increment in H2/N2 selectivity over the non‐confined reference MOF membrane. The performance of this new membrane sits in the optimal range above the Robeson upper bound. The membrane boasts a balanced high H2 permeability (>5000 Barrer) and selectivity (>50), significantly surpassing peer ZIF membranes.

Non‐selective Defect Minimization towards Highly Efficient Metal‐Organic Framework Membranes for Gas Separation

The persistence of defects in polycrystalline membranes poses a substantial obstacle to reaching the theoretical molecular sieving separation and scaling up production. The low membrane selectivity in most reported literature is largely due to the unavoidable non‐selective defects during synthesis, leading to a mismatch between the well‐defined pore structure of polycrystalline molecular sieve materials. This paper presents a novel approach for minimizing non‐selective defects in metal‐organic framework (MOF) membranes by a constricted crystal growth strategy in a confined environment. The in‐situ ZIF formation using the densely packed seeding array between the substrate and the pre‐grown top ZIF layer yields a confined membrane interlayer, which is highly uniform with a tightly packed crystalline structure. Unlike uncontrolled crystal growth, we purposely regulate the interlayer membrane growth in the direction parallel to the substrate. A notable 99% decrease in defects in the confined interlayer was achieved compared to the random‐grown top layer, leading to a ~353% increment in H2/N2 selectivity over the non‐confined reference MOF membrane. The performance of this new membrane sits in the optimal range above the Robeson upper bound. The membrane boasts a balanced high H2 permeability (>5000 Barrer) and selectivity (>50), significantly surpassing peer ZIF membranes.

Morphological Evolution of Metal‐Organic Frameworks into Hedrite, Sheaf and Spherulite Superstructures with Localized Different Coloration

The branched metal‐organic frameworks (MOFs) are the first superstructures of this kind, and the growth mechanism may explain crystal shapes of other materials. The mechanism of the formation of fascinating structures having a hedrite, sheaf or spherulite appearance are detailed. The branching can be controlled, resulting in crystals that either exhibit multiple generations of branching or a single generation. These structures might result from an increasing number of defects on fast‐grown rods. As the basal facets become less reactive, material is added to the prism facets, leading to secondary nucleation and triangular branches. These triangular structures are connected to the rod surface, growing longer than the central rod. Electron diffraction analyses show that the sheafs are polycrystalline structures with their fantails consisting of single‐crystalline nanorods deviating gradually from each‐other in their orientation. The crystallographic structure formed from achiral components consists of helical channels with opposite handedness. The accessibility of the nanochannels and the porosity of the superstructures are demonstrated by chromophore diffusion into the channels. The confinement and alignment of the chromophores inside the channels resulted in polarized‐light dependent coloration of the crystals; the polycrystallinity generated areas having different optical properties.

Synthesis and Characterization of Cobalt–Organic Framework as an Electrocatalyst for Water Splitting Application

ABSTRACTClimate change is seen as a crucial environmental dilemma that humanity will confront in the upcoming decade. For this purpose, the solvothermal‐assisted technique is used to create metal–organic frameworks (MOFs), which are porous materials characterized by strong connections between organic ligands and metal ions. The MOF discussed here contains cobalt as the metal node and a linker derived from 2‐aminobenzoic acid and terephthalaldehyde. The prepared powder underwent analysis using various techniques including Fourier‐transform infrared spectroscopy (FT‐IR), powder X‐ray diffraction (PXRD), scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET) surface area measurement, and thermal analysis. BET analysis revealed a surface area of 1587.06 m2/g, a total pore volume of 0.86394 cc/g, and an average pore size of 1.088 nm. The RGO@Co‐MOF prepared was utilized to evaluate water splitting efficiency, demonstrating favorable catalytic activity like most reported modified MOF catalysts under low current density conditions of 10 mA/cm2.

Optimizing Hygroscopic Metal–Organic Frameworks via EDTA‐Mediated Structural Reinforcement and Photothermal Modification

AbstractHygroscopic metal–organic frameworks (MOFs) are considered as superior moisture sorbents due to their highly adjustable and desired water adsorption/release performance, enabling effective atmospheric water harvesting (AWH) in arid regions. However, the water adsorption capacity, recycling stability, and functionality of current MOFs should be further improved to meet the requirements of practical AWH systems. Here the hydrophilicity at low relative humidity (RH) and cycling stability of MOF‐808 are simultaneously enhanced through the ethylenediaminetetraacetic acid (EDTA)‐mediated post‐modification. Based on the structural reinforcement, EDTA‐modified MOF‐808 (E‐MOF‐808) delivers a stable water uptake capacity of 0.39 g g−1 at 25% RH even after 50 water adsorption–desorption cycles, more than five times that of pristine MOF‐808. In addition, bridging by EDTA with the strong chelating ability, the E‐MOF‐808 can spontaneously capture Cu2+ for further functional improvement. Accordingly, light‐absorbing CuS nanoparticles can be in situ decorated on E‐MOF‐808 for facilitating solar‐driven water release. It is envisioned that this EDTA‐mediated function enhancement should provide valuable insights into the all‐in‐one design of versatile MOFs sorbents.

Metal Organic Framework‐Derived Anionic P‐Substitution toward CoNiSe‐P with Excellent Electrochemical Stability for Supercapacitor

AbstractThe regulation of nanostructures and composition can significantly enhance the electrochemical activity and accelerate electrochemical reaction kinetics of electrode material. Herein, metal organic framework(MOF) is used as self‐sacrificing templates to prepare CoNiSe‐P by hydrothermal with following selenylation and phosphorization treatment. Due to the hollow porous structure, rich electrochemical active sites and elements synergistic influence, the obtained CoNiSe‐P electrode shows a high capacity of 838 C g−1, which is much higher than CoNiSe (322 C g−1) and CoNiP (616 C g−1). Furthermore, CoNiSe‐P electrode shows excellent rate characteristic (685 C g−1 at 20 A g−1) and ultrahigh electrochemical stability with capacity retention of 99.6% after 10 000 cycles. More importantly, an asymmetric supercapacitor is assembled with CoNiSe‐P as the positive electrode and nitrogen‐doped porous carbon as the negative electrode delivers an energy density of 42.4 Wh kg−1 at 266.6 W kg−1 and maintains a specific capacitance of 96.8% after 10 000 cycles. Significantly, the asymmetric supercapacitor shows a high energy density up to 21.3 Wh kg−1 at a very high power density of 21.3 kW kg−1, higher than those of previously reported asymmetric supercapacitors.

Constructing Angstrom‐Level Ion Pocket Array in 1D Channel Wall for Efficient Lithium Ion Sieving

AbstractThe rapid development of new energy industry is leading to the scarcity of lithium (Li) metal. Rational design of adsorbents for efficient separation of Li+ ion from aqueous media is pivotal to solve the recovery of this valuable resource. Current adsorbents generally suffer from the drawbacks in adsorption capacity, kinetics, and selectivity. Herein, a novel and ultra‐stable metal–organic framework is designed for Li+ separation. The dense oxygen atoms on the cambered wall of its 1D channel encircle to form angstrom‐level tetrahedral ion pockets array, acting as the dominant adsorption sites. This rational distribution of the array avoids the pore blockage caused by the pre‐adsorbed ions, thereby accelerating the diffusion of subsequent ions into the interior pore. Meanwhile, this tetrahedral pocket shows distinct electronegativity and strong chelation effect for Li+. Benefiting from these specifics, this adsorbent exhibits a record‐breaking adsorption capacity for Li+ (76.1 mg g−1) and short equilibrium time (30 min). Moreover, the selective adsorption of Li+ over Na+, K+, Ca2+, and Mg2+ is achieved due to the matched Li+ ion diameter with the pocket/channel sizes and lower energy barrier for dehydration. Thus, this work proposes a feasible strategy for the construction of novel MOFs for ions adsorption.

Hydrogen-Bonded Organic Framework and Metal-Organic Framework Assembly of Waterwheel PgC-Noria Molecule: Regulating Microstructure Enables Iodine Transfer.

Hydrogen-bonded organic frameworks (HOFs) are a type of crystalline porous materials self-assembled from organic or metal-organic building blocks via intermolecular hydrogen bonding, which have received increasing attention due to their reversible and flexible hydrogen bonding properties. Currently, it remains a challenge to construct HOFs based on complex or porous organic cages as molecular building blocks. Herein, a 3D HOF (PgC-HOF) featuring honeycomb-shaped channels is crafted utilizing a sizable waterwheel-like PgC-noria organic molecule cage. The pivotal role of intermolecular multipoint hydrogen bonding interactions in upholding structural integrity and stability is underscored by the possession of 36 phenolic hydroxyl groups in PgC-HOF. Interestingly, the introduction of calcium ions into the reaction system results in the formation of the metal-organic framework (PgC-MOF), with the channel dimensions increasing from 6.8 to 9.1Å. Furthermore, I2 sorption/release experiments are conducted on PgC-HOF and PgC-MOF, achieving an increase in the optimal adsorption amount from 1.45 to 2.19gg-1 and a transition from an irreversible adsorbent to a reversible adsorbent.

Two New Coordination Polymers: Crystal Structures and Fluorescence Properties.

A new Ni (II) metal-organic frameworks with the formula [Ni2(HL)2(H2O)4]∙3H2O (1) and a novel phenoxo-O bridged rare-earth dinuclear Schiff base complex with the formula [La2(dbm)4L·CH3OH] (2), where the HL2- is the partial deprotonated of the organic ligand H3L, and H2L is a bis-Schiff foundation ligand (H3L = 4,6-dioxo-1,4,5,6-tetrahydro-1,3,5-triazine-2-carboxylic acid, H2L = N, N'-bis (2-hydroxy-3-methoxybenzylidene) -propane-1,2-diamine, Hdbm = dibenzoylmethane), have been successfully generated under the solvothermal condition. The targeted product sample of 1 and 2 has been fully characterized by single-crystal X-ray data, elemental analysis, FT-IR, powder X-ray diffraction, and thermogravimetric analysis. Furthermore, fluorescence performance testing of the complexes revealed that in complex 1, H3L forms a rigid chain through coordination with Ni2+ ions and further forms a highly rigid three-dimensional framework within the hydrogen bond network, resulting in fluorescence enhancement of up to 13.7-fold, displaying deep blue fluorescence with CIE coordinates of (0.1626, 0.1375). In contrast, complex 2 forms only discrete zero-dimensional molecules and exhibits light blue fluorescence with CIE coordinates of (0.1744, 0.2306). This demonstrates their potential as fluorescent materials.

Construction of NiFe2O4/Fe2O3@Ni(OH)2 hollow core–shell nanotubes based on metal–organic frameworks for efficient oxygen evolution electrocatalysis

Construction of NiFe2O4/Fe2O3@Ni(OH)2 hollow core–shell nanotubes based on metal–organic frameworks for efficient oxygen evolution electrocatalysis

Precision management of Fusarium fujikuroi in rice through seed coating with an enhanced nanopesticide using a tannic acid-ZnIIformulation.

Seed coating with fungicides is a common practice in controlling seed-borne diseases, but conventional methods often result in high toxicity to plants and soil. In this study, a nanoparticle formulation was successfully developed using the metal-organic framework UiO-66 as a carrier of the fungicide ipconazole (IPC), with a tannic acid (TA)-ZnII coating serving as a protective layer. The IPC@UiO-66-TA-ZnII nanoparticles provided a controlled release, triggered and regulated by environmental factors such as pH and temperature. This formulation efficiently controlled the proliferation of Fusarium fujikuroi spores, with high penetration into both rice roots and fungal mycelia. The product exhibited high antifungal activity, achieving control efficacy rates of 84.09% to 93.10%, low biotoxicity, and promoted rice growth. Compared to the IPC flowable suspension formula, IPC@UiO-66-TA-ZnII improved the physicochemical properties and enzymatic activities in soil. Importantly, it showed potential for mitigating damage to beneficial soil bacteria. This study provides a promising approach for managing plant diseases using nanoscale fungicides in seed treatment.

Two-Dimensional π-d Conjugated Conductive Metal-Organic Framework with Triple Active Centers as High-Performance Cathodes for Flexible Zinc Batteries.

Conductive metal-organic frameworks (C-MOFs) have received extensive interest in high-performance zinc-ion batteries (ZIBs) owing to multi-redox sites and high electrical conductivity. Here, we present a π-d C-MOF by coordinating 2,3,5,6-tetraaminobenzoquinone (TABQ) ligands with Cu2+ ions (2D Cu-TABQ) acting as cathodes for ZIBs. Benefiting from a triple active center (Cu2+, C=O, and C=N), 2D Cu-TABQ shows an ultra-high reversible capacity of 297.7 mAh g-1at 0.2 A g-1. Meanwhile, 2D Cu-TABQ also has superior cycle stability with a capacity of up to 98.2 mAh g-1 after 1000 times at 2.0 A g-1. Considering the instability of the ligand bonds of C-MOFs in aqueous electrolytes,this work uses gel electrolytes to reduce the dissolution of organic ligands into the electrolyte, thus suppressing the shuttle effect, significantly improving the cycling stability of 2D Cu-TABQ. The flexible battery assembled by 2D Cu-TABQ shows excellent capacity retention (64.4%) after 50 times at 0.2 A g-1, which is significantly better than 36.4% in the common electrolyte, as well as outstanding bending resistance and electrochemical properties at different folding angles. This investigation will highlight the electrochemical application of C-MOFs in flexible zinc ion batteries and offer novel ideas for the structural design of cathodes with multiple active centers.

Designing Artificial Laccase Catalysts by Introducing Substrate Oxidation Metals into Oxygen-Reducing Metal-Organic Frameworks: Cu-Doped ZIF-67.

Laccase, a multi-copper oxidase, is limited by its optimal temperature range and isolation costs. To overcome these challenges, we synthesized copper-doped zeolitic imidazolate framework-67 (Cu-doped ZIF-67) with 16 mol % Cu as an artificial laccase catalyst. The introduced Cu site acts as the phenol oxidation site, and Co-based ZIF-67 is the four-electron oxygen reduction site. Laccase also employs this division of oxidation and reduction sites. Cu-doped ZIF-67 demonstrated significant catalytic activity, superior to natural laccase, especially at elevated temperatures, and maintained stability across multiple reaction cycles. These findings suggest that Cu-doped ZIF-67 is a robust, reusable alternative for industrial applications requiring high thermal stability and efficient catalysis.

Heat up to catch carbon.

A metal-organic framework is activated to capture carbon dioxide at high temperatures.

High-temperature carbon dioxide capture in a porous material with terminal zinc hydride sites.

Carbon capture can mitigate point-source carbon dioxide (CO2) emissions, but hurdles remain that impede the widespread adoption of amine-based technologies. Capturing CO2 at temperatures closer to those of many industrial exhaust streams (>200°C) is of interest, although metal oxide absorbents that operate at these temperatures typically exhibit sluggish CO2 absorption kinetics and instability to cycling. Here, we report a porous metal-organic framework featuring terminal zinc hydride sites that reversibly bind CO2 at temperatures above 200°C-conditions that are unprecedented for intrinsically porous materials. Gas adsorption, structural, spectroscopic, and computational analyses elucidate the rapid, reversible nature of this transformation. Extended cycling and breakthrough analyses reveal that the material is capable of deep carbon capture at low CO2 concentrations and high temperatures relevant to postcombustion capture.

Isoreticular Squaraine-Linked Titanium-Organic Frameworks for Photocatalytic Water Splitting to Hydrogen Under Visible Light.

Inspired by the excellent photocatalytic activity of TiO2, titanium metal-organic frameworks (Ti-MOFs) with broad absorption of visible light are regarded as promising photocatalysts, but carboxylate-linkers used in them are mainly limited to the large extended π-electron systems. Developing Ti-MOFs using organic linkers with a donor-acceptor-donor (D-A-D) structure is expected to improve their charge separation but is still challenging. Herein the design of two new isoreticular Ti-MOFs, Ti6-SQ1 and Ti6-SQ2 are reported, by using squaraines bearing different electron donors as organic linkers. Discrete fourier transform (DFT) calculations demonstrate that ligand-to-metal charge transfer (LMCT) from the acceptor units of squaraines to the Ti6-oxo secondary building units (SBUs) drives the photocatalytic water splitting to hydrogen reaction. Compared with Ti6-SQ2, the shorter distance between the squaraine centers and the Ti6-oxo SBUs in Ti6-SQ1 makes stronger LMCT, showing higher photocatalytic hydrogen evolution efficiency of 11.5mmol g-1h-1 under visible light (λ > 420nm), which is ≈8 times that of Ti-based MOF photocatalysts reported so far. This work provides a new strategy to design Ti-MOF photocatalysts and understand their structure-property relationship.