Porous Metal-organic Frameworks Research Articles

Pore design of POM@MOF hybrids for enhanced methylene blue capture

Abstract Adsorption of methylene blue from aqueous effluents is a key technique to treat wastewater discharge from chemical industries. Toward methylene blue adsorption, porous metal–organic frameworks have been promising owing to their high surface areas and tunable porosity. The incorporation of polyoxometalates (POMs) into metal–organic frameworks has been found to facilitate methylene blue adsorption due to electrostatic interactions between the anionic polyoxometalate and the cationic methylene blue. However, it remains unclear how the customizable pore of POM@MOF hybrids affects the capture of methylene blue. In this work, we study the effect of the size and environment of metal–organic frameworks on the property of methylene blue capture for [Zr6O4(OH)4(1,4-benzenedicarboxylate)6] (UiO-66) embedding an α-Keggin-type polyoxometalate [α-SiW12O40]4− (SiW12). Tuning pore size and environment based on ligand engineering of the metal–organic frameworks suggests that (i) lengthening the organic linkers and (ii) functionalization of the linker with −NO2 groups could enhance the methylene blue uptakes. Notably, an increase in the loading amounts of SiW12 on UiO-66 functionalized with −NO2 groups led to outstanding methylene blue capture, comparable to that of representative zeolites such as ZSM-5 and zeolite Y.

Highly plasticization-resistant Tröger’s base polymer–MOF mixed-matrix membranes for stable gas separation

The plasticization phenomenon, characterized by polymer chain swelling when exposed to highly soluble gas at high feed pressure, has been a major problem for polymer membranes. To address this, we prepared Tröger’s base (TB) polymer-based metal–organic framework (MOF) mixed-matrix membranes (MMMs), which are highly plasticization-resistant membranes. Three different highly porous MOF nanoparticles (ZIF-8, UiO-66-NH2, and MIL-101(Cr)) were prepared in small particle sizes. The corresponding MMMs were formed with a 30 wt% MOF loading to study the effects of MOF species, particle size, chemical functionality, and MOF–polymer interfacial interaction on gas-transport properties and plasticization behavior. The TB polymer-based MOF MMMs exhibited significantly higher H2 and CO2 permeabilities (fourfold to eightfold) than the TB polymer membrane owing to the porous nature and high gas adsorption capacity of the MOF. Additionally, the TB-based MOF MMMs, particularly the UiO-66-NH2 MMM, displayed exceptional CO2 plasticization resistance. This is attributed to the interfacial interaction of the strong hydrogen bonding between the amine group of the TB polymer and the amino group of UiO-66-NH2, as confirmed by small-angle X-ray scattering characterization. This TB polymer-based MOF MMM approach provides a feasible and effective route for enhancing gas-transport properties and CO2 plasticization resistance to achieve energy-efficient and stable gas separation.

The Central Role of Oxo Clusters in Zirconium‐Based Esterification Catalysis

Oxo clusters are a unique link between oxide nanocrystals and Metal‐Organic Frameworks (MOFs), representing the limit of downscaling each of the respective crystals. Herein, the superior catalytic activity of clusters, compared to zirconium MOF UiO‐66 and nanocrystals is shown. Focus is on esterification reactions given their general importance in consumer products and the challenge of converting large substrates. Oxo clusters have a higher surface‐to‐volume ratio than nanocrystals, rendering them more active. For large substrates, for example, oleic acid, MOF UiO‐66 has negligible catalytic activity while clusters provide almost quantitative conversion, a fact we ascribe to limited diffusion of large substrates through the MOF pores. Clusters do not suffer from limited mass transfer and we also obtain high conversion in solvent‐free reactions with sterically hindered alcohols (hexanol, 2‐ethyl hexanol, benzyl alcohol, and neopentyl alcohol). The cluster catalyst can be recovered and shows identical activity when reused. The structural integrity of the cluster is confirmed using X‐ray total scattering and pair distribution function analysis. Moreover, when homogeneous zirconium alkoxides are used as catalysts, the same oxo cluster is retrieved, showing that oxo clusters are the active catalytic species, even in previously assumed homogeneously catalyzed reactions.

Synergistic effect of Gemcitabin-loaded metal organic frameworks nanoparticles with particle therapy

Combination of nanoagents with radiations has opened up new perspectives in cancer treatment, improving both tumor diagnosis and therapeutic index. This work presents the first investigation of an innovative strategy that combines porous metal–organic frameworks (nanoMOFs) loaded with the anti-cancer drug Gemcitabine monophosphate (GemMP) and particle therapy-a globally emerging technique that offers more precise radiation targeting and enhanced biological efficacy compared to conventional radiotherapy. This radiochemotherapy has been confronted with two major obstacles limiting the efficacy of therapeutics when tested in vivo: (i) the presence of hypoxia, one of the most important causes for radiotherapy failure and (ii) the presence of a microenvironment, main biological barrier to the direct penetration of nanoparticles into cancer cells.On the one hand, this study explore the effects of hypoxia on drug delivery systems in combination with radiation, demonstrating that GemMP-loaded nanoMOFs significantly enhance the anticancer efficacy of particle therapy under both normoxic (pO2 = 20 %) and hypoxic (pO2 = 0.5 %) conditions. Notably, the presence of GemMP-loaded nanoMOFs allows the irradiation dose to be reduced by 1.4-fold in normoxia and at least 1.6-fold in hypoxia, achieving the same cytotoxic effect (SF=10 %) as carbon or helium ions alone. Synergistic effects between GemMP-loaded nanoMOFs and radiations have been observed and quantified. On the other hand, we also highlighted the ability of the nanoMOFs to diffuse through an extracellular matrix and accumulate in cells. An higher effect of the encapsulated GemMP than the free drug was observed, confirming the key role of the nanoMOFs in transporting the active substance to the cancer cells as a Trojan horse. This paves the way to the design of “all-in-one” nanodrugs where each component plays a role in the optimization of cancer therapy to maximize cytotoxic effects on hypoxic tumor cells while minimizing toxicity on healthy tissue.

Aromatic pore engineering in microporous metal–organic frameworks for high-production one-step methane purification from ternary alkanes mixtures

The exploitation of competent isolation and purification technology of methane (CH4) is an imperative and challenging task for full utilization of clean natural gas in petrochemical industry. Compared to traditional energy-intensive low-temperature distillation, adsorptive separation using porous metal–organic framework (MOF) materials provides an alternative technique with low energy consumption and high efficiency. In this situation, an aromatic pore engineering strategy in a series of pillar-layered Zn-based MOFs by introducing organic linkers with different degrees of aromatic units was investigated to tune pore size and pore environment for simultaneously removing propane (C3H8) and ethane (C2H6) from C3H8/C2H6/CH4 mixtures. Compared to the other two analogues, i.e. Zn(BDC)(TED)0.5 and Zn(ADC)(TED)0.5, obtained Zn(NDC)(TED)0.5 showed high adsorption capacity for C3H8 (5.18 mmol/g) and C2H6 (5.04 mmol/g) and selectivity for C3H8/CH4 and C2H6/CH4 at 298 K and 1.0 bar. Breakthrough tests proved the three MOFs can effectively separate ternary C3H8/C2H6/CH4 mixtures, and Zn(NDC)(TED)0.5 especially exhibited excellent high-purity CH4 yield of 10.07 mmol/g. Computational simulations showed that suitable pore space and surface aromatic environment in Zn(NDC)(TED)0.5 created beneficial interactions with C3H8 and C2H6 molecules, which ultimately contributed to its favourable adsorption and separation property. This system work provides insights for the development of pore control method in MOF materials for natural gas purification.

Preparation of NH2-MIL-101(Fe) Metal Organic Framework and Its Performance in Adsorbing and Removing Tetracycline.

Tetracycline's accumulation in the environment poses threats to human health and the ecological balance, necessitating efficient and rapid removal methods. Novel porous metal-organic framework (MOF) materials have garnered significant attention in academia due to their distinctive characteristics. This paper focuses on studying the adsorption and removal performance of amino-modified MIL-101(Fe) materials towards tetracycline, along with their adsorption mechanisms. The main research objectives and conclusions are as follows: (1) NH2-MIL-101(Fe) MOF materials were successfully synthesized via the solvothermal method, confirmed through various characterization techniques including XRD, FT-IR, SEM, EDS, XPS, BET, and TGA. (2) NH2-MIL-101(Fe) exhibited a 40% enhancement in tetracycline adsorption performance compared to MIL-101(Fe), primarily through chemical adsorption following pseudo-second-order kinetics. The adsorption process conformed well to Freundlich isotherm models, indicating multilayer and heterogeneous adsorption characteristics. Thermodynamic analysis revealed the adsorption process as a spontaneous endothermic reaction. (3) An increased adsorbent dosage and temperature correspondingly improved NH2-MIL-101(Fe)'s adsorption efficiency, with optimal performance observed under neutral pH conditions. These findings provide new strategies for the effective removal of tetracycline from the environment, thus holding significant implications for environmental protection.

Multimaterial Digital-Light Processing of Metal-Organic Framework (MOF) Composites: A Versatile Tool for the Rapid Microfabrication of MOF-Based Devices.

Patterning Metal-Organic Frameworks (MOFs) is essential for their use in sensing, electronics, photonics, and encryption technologies. However, current lithography methods are limited in their ability to pattern more than two MOFs, hindering the potential for creating advanced multifunctional surfaces. Additionally, balancing design flexibility, simplicity, and cost often results in compromises. This study addresses these challenges by combining Digital-Light Processing (DLP) with a capillary-assisted stop-flow system to enable multimaterial MOF patterning. It demonstrates the desktop fabrication of multiplexed arbitrary micropatterns across cm-scale areas while preserving the MOF's pore accessibility. The ink, consisting of a MOF crystal suspension in a low volatile solvent, a mixture of high molecular weight oligomers, and a photoinitiator, is confined by capillarity in the DLP projection area and quickly exchanged using syringe pumps. The versatility of this method is demonstrated by the direct printing of a ZIF-8-based luminescent oxygen sensor, a 5-component dynamic information concealment method, and a PCN-224-based colorimetric sensor for amines, covering disparate pore and analyte sizes. The multi-MOF capabilities, simplicity, and accessibility of this strategy pave the way for the facile exploration of MOF materials across a wide range of applications, with the potential to significantly accelerate the design-to-application cycle of MOF-based devices.

Synergistic ionic liquid encapsulated MIL-101 (Cr) metal-organic frameworks for an innovative adsorption desalination system

The transformations of brackish water into freshwater employing porous materials such as metal-organic frameworks (MOFs) show a great potential for a green environment. But the adsorption-based desalination slows down due to slow water adsorption/desorption rates and inadequate water storage capacity in conventional adsorbents. Therefore, the restructuring of porous MOFs increases water storage and transfer rates. This paper presents a comprehensive investigation on the fabrication of ionic liquid encapsulated MIL-101 (Cr) MOFs (metal-organic frameworks), and its interactions with water for desalination applications. Firstly, the pristine MIL-101 (Cr) is encapsulated with various types/amounts of ionic liquids. Next, these MOFs are characterized via SEM (Scanning electron microscope), FTIR (Fourier transform infrared), XRD (X-ray diffraction), TGA (Thermal gravimetric analysis), N2 adsorption techniques. The water adsorption on these MOFs is performed experimentally for a wide temperature (30–80 °C) and pressure (0 < P/Ps < 0.95) ranges. The effects of the size (or type) as well as the encapsulation ratio of ionic liquids on water adsorption behaviors are conducted. Based on the experimentally proven water adsorption (isotherms and kinetics) data, an AD (adsorption desalination) system is modelled and simulated. Finally, the AD performances in terms of the specific daily water production (SDWP) and performance ratio (PR) are parametrically studied with respect to various regeneration temperature (50–80 °C) and cycle times (100 s–1000 s). It is found that by ionic liquid encapsulation, the water uptakes/offtake rates are expedited up to 48% (for adsorption)/55% (for desorption), respectively. In addition, the water transfer (Δq) improves up to 45% more than the parent MIL-101(Cr) MOFs. Furthermore, the SDWP increases from 38 to 56 m3 of water per tonne of MOFs per day at the regeneration temperature of 70 °C. The simulation results also show that the ionic-liquid-encapsulated MIL-101 (Cr) MOFs generates water (>25 m3 water per tonne of IL-MOFs) at the regeneration temperature of 50 °C and is potential for the next generation desalination applications.

An Ultramicroporous Zinc‐Based Zeolitic Imidazolate Framework‐8 for the Adsorption of CO2, CH4, CO, N2 and H2: A Combined Experimental and Theoretical Study

AbstractAn alternative synthesis route to obtain ultramicroporous zeolitic imidazolate framework‐8 (ZIF‐8) is reported that is rapid and does not require organic solvent or heating. The polyethylene glycol‐templated ZIF‐8 nanoparticles (&lt;50 nm size) exhibited a high BET (Brunauer, Emmett and Teller) surface area of 1853 m2/g, a total pore volume of 0.73 cm3/g, and 0.54 nm ultramicropores. A new approach is introduced here to better understand gas adsorption in porous metal organic frameworks (MOFs) that combines theoretical and experimental isotherm data obtained for five gases with statistical physics modelling. The multiscale analytical model reveals that the gas molecules, irrespective of their structure, adsorb in a mixed orientation at low temperature, and a parallel multi‐molecular orientation at higher temperature. The number of gas molecules adsorbed per site ranged from 0.83–2.2 while the number of adsorbent layers ranged between 1.4–5.6, depending on the gas and the temperature. The multilayer adsorption processes involved adsorption energies from 2.85 kJ/mol–9.77 kJ/mol for all gases, consistent with physisorption via van der Waals and London dispersion forces. The initial adsorption energies were higher and therefore stronger. A particularly high capacity for CO2 of 1088 mg(CO2)/g at 298 K was observed while H2 adsorption was only 9 mg(H2)/g. The other gases adsorbed at 145 mg/g–245 mg/g at 298 K. Thermodynamic functions that governed the adsorption process such as the internal energy, the enthalpy, and Gibbs free energy, are also reported, as well as the adsorption entropies, for the 5 gases.

Eco-friendly and cost-effective synthesis of hierarchical porous HKUST-1 from thin waste electric cables for enhanced cationic dye removal

HKUST-1, as a type of metal-organic framework (MOF), has attracted significant interest for various applications. However, its use for adsorption applications is hindered by its microporous structure, which negatively impacts the diffusion and mass transfer of large particles (> 2 nm). Concurrently, waste electric cables from discarded vehicles and electronic equipment pose significant environmental challenges. To address these issues, we developed a novel recycling method using copper hydroxide recovered from waste-thin electric cables as the metal source for synthesizing hierarchical porous HKUST-1 (W) using a green approach at a low temperature. The resulting HKUST-1 (W) exhibited interesting properties compared to the typical HKUST-1 (C) synthesized from commercial precursors, showing a microporous-mesoporous structure with enhanced molecular mass transport, while HKUST-1 (C) exhibited only micropores. Moreover, the waste-derived HKUST-1 (W) formed interconnected small particles with enhanced methylene blue (MB) removal properties compared to HKUST-1 (C), mainly due to its hierarchical porous structure facilitating easy mass transfer of MB. To evaluate the industrial potential of our adsorbent, we conducted a fixed-bed adsorption column (FBAC) experiment, which showed that HKUST-1 (W) achieved a high removal efficiency of 99 %, confirming its effectiveness as a dye adsorbent in both batch experiments and a FBAC. This approach opens new perspectives in applying upcycled waste-based materials in synthesizing hierarchical porous MOFs.

Three-dimensional linker-promoted hierarchical porous metal–organic framework for natural gas purification

The purification of methane from natural gas is extremely important for industrial applications. In this study, hierarchical porous material LIFM-Z1 with microporous cages and mesoporous hexagonal one-dimensional channels was successfully synthesized and evaluated. The results show that LIFM-Z1 can effectively separate CH4 from the mixed gas containing CH4, C2H6, C3H8 and n-C4H10. Single-component adsorption experiments revealed the selective adsorption ability of LIFM-Z1 for C2H6, C3H8, and n-C4H10, enabling a clear distinction between these components and CH4. This selectivity was further verified by dynamic breakthrough experiments. Theoretical analysis shows that the interaction between LIFM-Z1 and gas molecules mainly depends on the synergistic effect of C–H⋯O hydrogen bond and C–H⋯C van der Waals force. The results highlight the potential of utilizing 3D linkers to enhance the inner wall interaction with CH4 and its related gases in MOF construction. These characteristics of LIFM-Z1 not only successfully demonstrate the potential of separation and purification of natural gas with high efficiency, but also show its broad application prospects in the actual natural gas processing.

Planar Group Functionalization of Quasi-Discrete Pores in Metal-Organic Frameworks for Enhanced Isomeric Separation in Simulated Moving Bed Processes.

The efficient separation of 4-methyl-1-pentene (4MP1) from its structural isomers is crucial for industrial applications but remains challenging due to the similar physicochemical properties of these compounds. This study introduces a novel strategy using metal-organic frameworks (MOFs), specifically an engineered variant of ZIF-108, which demonstrates remarkable improvements in the thermodynamic and kinetic properties for 4MP1 separation. By substituting the methyl groups in ZIF-8 with planar nitro groups, we achieved a strategic resizing of the pore windows and cavity dimensions in ZIF-108. This adjustment not only enhanced the molecular affinity and selectivity toward 4MP1 but also facilitated a diffusion rate that is 164 times faster than that observed in ZIF-8. These properties significantly elevated the performance of ZIF-108 in simulated moving bed (SMB) processes, achieving up to 96.5% recovery of high-purity 4MP1, outperforming traditional adsorbents. Comprehensive characterization, including density functional theory (DFT) calculations and molecular dynamics (MD) simulations, provided insights into the interactions and the stability of the adsorption process. The findings suggest that the strategic modification of the pore architecture in MOFs holds significant potential for optimizing the separation processes of industrially relevant mixtures.

Porous Metal Organic Framework (MOF) derived dimorphic (n-ZnO/p-NiO) Z-scheme heterojunction anchored with MWCNTs (ternary nano-architecture): A novel approach for optimization of photodegradation mechanism and kinetics of Congo red (CR) dye

Global efforts to combat water pollution, especially from organic dyes like Congo red, emphasize the use of advanced nanomaterials for sewage purification. Metal-Organic Frameworks (MOFs), known for their crystalline structures and versatile properties, have become pivotal in wastewater treatment research. Integrating MWCNTs into MOF derived composite nanostructures is a strategic advancement, boosting the efficiency of photocatalytic systems and addressing environmental concerns. This study details the synthesis of a novel Z-scheme heterojunction nanocomposite (n-ZnO/p-NiO) incorporating multi-walled carbon nanotubes (MWCNTs), achieved via a solvothermal method using metal-organic framework (MOF) as a template. The study uses XRD, FTIR, FESEM, BET, UV, and PL for comprehensive nanocomposite characterization, offering insights into its structural, morphological, and optical properties. The resultant nanocomposite displays high surface area, sturdy pore arrangement, and consistent morphology. MWCNTs influence crystal growth and optical absorption, enhancing surface hydroxyl group concentration and acting as electron acceptors. This results in decreased photo oxidation and improved overall stability under light exposure in the composite. The composite achieves 92 % Congo red degradation in 60 min under UV light, showcasing superior dye adsorption capacity. This underscores its potential as an efficient photocatalyst for environmental remediation and wastewater treatment.

Porous Frustrated Lewis Pairs Catalyst Constructed on Defective Zirconium-Based Metal-Organic Frameworks for Hydrogenation Reactions with H2.

A porous metal-organic framework (MOF)-based frustrated Lewis pairs (FLPs) were prepared via a ligand replacement strategy to generate organic linker defects in zirconium-based MOF (MOF-808), thereby exposing Zr sites as Lewis acid. Due to the rigid features of the MOF skeleton, the unsaturated metal cluster and the adjacent lattice oxygen (Lewis bases) are in sterically hindered positions, which formed FLP sites with efficient H2 activation ability. This porous heterogeneous FLP catalyst [MOF-808-OH (15%)] exhibits high performance styrene hydrogenation to ethylbenzene with 99% yield. The high structural stability and reusability enabled the catalyst to maintain an over 98% activity after five cycles. This work provides a defect modulation strategy to prepare MOF-based solid FLP catalysts.

Fluorinated metal-organic framework aerogels with enhanced moisture resistance and efficient gas diffusion for CO2 capture

Escalating CO2 levels in confined spaces threatens human well-being and safety, underscoring the urgent need for effective CO2 mitigation strategies. Metal-organic frameworks (MOFs), with their large surface areas and capacious pores, represent a promising avenue for CO2 capture. However, their application is often limited by susceptibility to moisture and lack of uniformity in mesopore distribution. Here, we present a novel approach involving ligand fluorination modification and pore reconstruction to fabricate ultralight, highly moisture resistant, and hierarchically porous UiO-66-NH2-F4 aerogels. This design ingenuity promotes the formation of an efficient gas transport network and generates an abundance of micropores decorated with hydrophobic units, effectively shielding CO2 adsorption from the interference of water molecules. The UiO-66-NH2-F4 aerogels exhibit an impressive CO2 adsorption capacity of 5.18 mmol/g (dry) and 4.48 mmol/g (70 % RH) at 298 K, a remarkable CO2/N2 selectivity of 29, and exceptional cyclability. Density functional theory (DFT) calculations further elucidate the robust binding interactions of these CO2-selective UiO-66-NH2-F4 aerogels, attributing them to the tailed pore environment created by fluorinated hydrophobic groups and the accessibility of adsorption sites. This work charts a promising course for developing moisture-resistant and hierarchically porous MOF aerogels, which are poised to revolutionize CO2 adsorption practices in confined environments.

Combined Effect of Hydrophilic Pore and the Type of Protons on Proton Conductivity in Porous Metal-Organic Frameworks: A Feasible Approach to Achieve a Super Proton Conductor under Hydrated Conditions.

There has been a steady growth of interest in proton-conductive metal-organic frameworks (MOFs) due to their potential utility in proton-exchange membrane fuel cells. To attain a super proton conductivity (>1 × 10-2 S cm-1) in a MOF-based proton conductor is a key step toward practical application. Currently, most studies are focused on enhancing the proton conductivity of porous MOFs by controlling a single factor, such as the type of protons or hydrophilic pore or hydrogen bond. However, a limited contribution from a single factor cannot afford to remarkably increase the proton conductivity of the MOF and form a super proton conductor. Herein, we constructed two distinct porous MOFs, {(H3O+)4[Cu12(ci)12(OH)4(H2O)12]·3H2O·9DMF} (Cu-ci-3D, H2ci = 1H-indazole-5-carboxylic acid, DMF = N,N'-dimethylformamide) and {[Co(Hppca)2]·2HN(CH3)2·CH3OH·2H2O} (Co-ppca-2D, H2ppca = 5-(pyridin-3-yl)-1H-pyrazole-3-carboxylic acid), to tune their proton conductivities at high relative humidity (RH) using the combined effect of hydrophilic pore and the type of protons, ultimately achieving super proton conduction. Excitingly, Cu-ci-3D indeed harvests a super proton conductivity of 1.37 × 10-2 S cm-1 at 353 K and ∼97% RH, superior to some previously reported MOF-based proton conductors. The results present a unique perspective for developing high-performance MOF-based proton conductors and understanding their structure-performance relationships.

A One-Nano MOF-Two-Functions Strategy Toward Self-healing, Anti-inflammatory, and Antibacterial Hydrogels for Infected Wound Repair

Porous metal–organic frameworks (MOF)-based hydrogels have recently attracted wide attention in sensing, catalysis, water treatment, and biomedicine. Yet, limited by challenges of insufficient stability, inordinate metal-ion leakage, and weak wound healing efficacy, the design of MOF-based hydrogel dressings for infected wounds has been rarely explored. Here, we propose a “one-nano MOF-two-functions” strategy to demonstrate the molecular engineering of a chemically stable nano MOF, which acts as both a carrier and a dynamic cross-linker, to fabricate functional composite hydrogels. The active amino groups of the MOF are employed to create dynamic networks with aldehyde-bearing alginate, ensuring excellent compatibility of the MOF with the polymer matrix and imparting effective self-healing properties to the resulting hydrogels. Simultaneously, two active ingredients, Cu nanoparticles (NPs) and curcumin, can be loaded into the nano MOF, achieving synergistic anti-inflammatory and antibacterial effects. Assisted by the mechanical stability and drug co-delivery in an infected full-thickness skin model, the MOF-based hydrogel can reduce the bacterial load on the wound by ∼103 times, and promote collagen deposition and angiogenesis by ∼1.5 and ∼3 times, compared with the control group. The “one-nano MOF-two-functions” design exhibits significant potential for high-performance infected wound dressings.

Chelated Metal-Organic Frameworks for Improved the Performance of High-Nickel Cathodes in Lithium-Ion Batteries.

Lithium-ion batteries have gained widespread use in various applications, including portable devices, electric vehicles, and energy storage systems. High Ni cathode, LiNixCoyMnzO2 (NCM, x ≥ 0.8, x + y + z = 1), have garnered significant attention owing to their high energy density. However, the limited lithium-ion transfer rate and transition metal cross-talk to anode pose obstacles to further improvement of electrochemical performance. To tackle these challenges, metal-organic frameworks (MOFs) with chelating agents are employed as additive materials for electrode. MOFs with chelating agents offer three key attributes: (1) Effective mitigation of transition metal cross-talk to the anode, (2) Partial desolvation of Li+ ions through MOF pores, and (3) Immobilization of anions via metal sites in the MOF. Leveraging these advantages, the chelating MOF-modified NCM cathode demonstrates reduced charge transfer resistance, both in their pristine and cycled states. In addition, they exhibit significantly improved lithium-ion diffusion coefficients after 100 cycles. These findings underscore the potential of MOFs with chelating agents as promising additive materials for enhancing the performance of LIBs.

Integrating Biocatalysts into Metal-Organic Frameworks: Disentangling the Roles of Affinity, Molecular Weight, and Size.

The integration of biocatalysts within metal-organic frameworks (MOFs) is attracting growing interest due to its potential to both enhance biocatalyst stability and sustain biocatalyst activity in organic solvents. However, the factors that facilitate the post-synthetic infiltration of such large molecules into MOF pores remain unclear. This systematic study enabled the identification of the influence of biocatalyst molecular size, molecular weight and affinity on the uptake by an archetypal MOF, NU-1000. We analyzed a range of six biocatalysts with molecular weights from 1.9 kDa to 44.4 kDa, respectively. By employing a combination of fluorescence tagging and 3D-STED confocal laser scanning microscopy, we distinguished between biocatalysts that were internalized within the MOF pores and those sterically excluded. The catalytic functions of the biocatalysts hosted within the MOF were investigated and found to show strong variations relative to the solvated case, ranging from a two-fold increase to a strong decrease.

Exploring Biliverdin's Molecular Interactions with Cu- and Fe-Based MOFs: A Unified In Vitro Study with Photoacoustic Analysis.

Metal-organic frameworks (MOFs) have shown promise in enhancing the stability of biomolecules. Herein, biliverdin (BVD), a photoacoustic (PA) and fluorescent agent, was immobilized within the pores of NH2-MIL-101 (Fe) (FeMOFs) and on the surface of CuBTC crystallites (CuMOFs). MOFs were found to enhance the fluorescence emission and quench the PA intensity of biliverdin. Fluorescence and PA studies, in tandem with DFT simulations, demonstrated that the spectral interactions between MOFs and BVD resulted from interactions between biliverdin and the MOF pores and surfaces in addition to alterations in the HOMO-LUMO energy gap. The MOF internal structure of the MOF played a role in BVD loading, with the FeMOFs enabling greater BVD encapsulation, while CuMOF interactions with BVD primarily took place on the MOF surface. The role of these surface vs pore interactions in the release of biliverdin was explored. This study demonstrates that the effects of the MOF internal structure, surface interactions, and energy interactions should be taken into consideration for biomolecule loading in MOFs.