Applications Of Metal-organic Frameworks Research Articles

Application of metal organic frameworks ZIF-8-based solid catalyst with hierarchical porous structure and Brønsted-Lewis dual acid sites ionic liquids for sustainable biodiesel production from acidic soybean oil

In order to alleviate the mass transfer limitation of triglyceride macromolecules on the solid catalyst surface during the catalytic oil transformation process, the utilization of hierarchical porous solid catalyst is a feasible method. For reaching this goal, the hierarchical porous support of H-ZIF-8 was initially prepared by incorporating the three-dimensional ordered macro and mesoporous into the ZIF-8 using polystyrene spheres (PS) as a hard template. Subsequently, the phosphotungstate anion PW12O403- (PW) decorated sulfonated 4,4'-dipyridinium ionic liquid with Keggin structure, namely [DPySO3H]1.5PW, was encapsulated in the H-ZIF-8 support, with the formation of the novel [DPySO3H]1.5PW@H-ZIF-8 catalyst. The so-synthesized solid catalysts featured with ordered hierarchical porous structure and dual Lewis and Brønsted acidic properties, with large BET surface area of 267.38 m2/g. This catalyst had high catalytic performances for the concurrent transformation of triglycerides and free fatty acids to biodiesel in a heterogeneous manner. Under the optimal reaction parameters (methanol/oil molar ratio: 30:1; catalyst dosage: 4 wt%; reaction time: 8 h; reaction temperature: 130 °C), the oil conversion level of 91.2% and entire conversion of free fatty acids could be attained by applying this [DPySO3H]1.5PW@H-ZIF-8 catalyst. The high catalytic activity of this catalyst was due primarily to the increased mass transfer efficiency and synergism of Lewis and Brønsted acid sites. Moreover, the good FFA and moisture-resistance capacity was also shown for this catalyst even in the case of moisture content of 5 % and FFA content of 40 % in the oil feedstock. This solid catalyst could be reused by simple filtration and displayed good reusability, still attaining over 80% oil conversion at the fourth reuse cycles thanks to the robust interactions between the acidic active centers and the hierarchical porous support. The kinetic analysis indicated that the activation energy Ea and Arrhenius constant A for this solid acid-catalyzed transesterification process were 56.0 kJ/mol and 7.8×104 min-1, respectively. This research would provide a new approach for the development of hierarchical porous solid catalysts, enabling the one-step transformation of low-grade acidic oils into biodiesel in a more sustainable and environmentally friendly way.

Deep-Eutectic-Solvent-Decorated Metal–Organic Framework for Food and Environmental Sample Preparation

Deep eutectic solvent (DES) is distinguished by its unique solvent properties, chemical stability, and eco-friendly nature, which are pivotal in a spectrum of chemical processes. It enhances the sample preparation process by increasing efficiency and minimizing the environmental impact. Metal–organic frameworks (MOFs), which are porous structures formed through coordination bonds between metal ions and organic ligands, are defined by their adjustable pore dimensions, extensive surface areas, and customizable architectures. The integration of DES within MOF to create DES@MOF capitalizes on the beneficial attributes of both materials, augmenting MOFs’ stability and versatility while providing a multifunctional carrier for DES. This composite material is both highly stable and readily tunable, establishing it as a leading contender for applications in sample preparation for food and environmental samples. This comprehensive review explores the application of DES-decorated MOF in food and environmental sample preparation and highlights the expansive potential of DES@MOF in diverse fields. We provide a detailed analysis of the characteristics of DES@MOF and its individual components, methods for decorating MOFs with DES, the advantages of these composite materials in sample pretreatment, and their specific applications in food safety and environmental monitoring. DESs are employed to modify MOFs, offering a multitude of benefits that can substantially improve the overall performance and applicability of MOFs. The review also discusses current challenges and future directions in this field, offering valuable insights for further research and development. The synergistic effects of DES and MOFs offer new opportunities for applications in food safety and other areas, leading to the development of more efficient, sensitive, and environmentally friendly analytical methods. This collaboration paves the way for sustainable technologies and innovative solutions to complex challenges.

Gas adsorption and separation applications of MOF materials

Abstract. Low-carbon hydrocarbons (C1-C4) are really important raw materials used in making different kinds of big molecules and stuff in industries. Before, people mostly used super cold cooling and a method where stuff gets soaked up. But these ways need big machines and use a lot of energy. So, scientists are trying to make new ways to separate things that don't use as much energy. One great idea is using how different gases stick to things to separate them. This idea could be a brilliant way to replace the old methods. The most important part of this idea is making things that can stick to the gases. There's this special material called metal-organic frameworks (MOFs) that's a mix of things from nature and chemicals. It has tiny holes and places that can do special things, and it's being studied a lot for separating gases. Traditional porous materials like activated carbon, silica gel, and molecular sieves have been widely used in industries, which has greatly contributed to industrial growth and people's living standards. MOFs have changeable structures and spots that can do special things. By changing the metal bits or the organic parts, we can control the size of the holes in MOFs, the special spots, and how much surface they have. These things make MOFs useful for storing gases, separating stuff by sticking and making reactions happen in fields like chemistry [1-3]. This paper explores the categories of MOF applications.

High-Valence Co Stabilized by In-Situ Growth of ZIF-67 on NiCo-LDH for Enhanced Performance in Oxygen Evolution Reaction.

The application of metal-organic frameworks (MOFs) in the electro-catalysis of heterogeneous structures is limited by the problems of low electrical conductivity and poor mechanical strength due to the complex synthesis process, although their high specific surface area and controllable structure. In this study, a method involving metal precipitation and ligand reaction is used during the electrochemical corrosion of hydroxides/oxy-hydroxides to obtain ZIF-67 in situ. The in situ growth technology not only effectively addresses the bonding strength and material conductivity challenges in the heterostructure between MOFs and the substrate but also enhances the catalyst's surface area and activity. Additionally, the exposure and protection of Co4+ by ZIF-67 contribute to the electrocatalyst's performance, demonstrating a low overpotential (η100) of 293mV, a Tafel slope of 25.8mV dec-1, and a charge transfer resistance of 3.9 Ω, with long-term robustness proven in continuous stability test exceeding 75000 s under the superhigh current density of 500mA cm-2. This work on binder-free in situ growth of MOFs not only provides relevant theoretical insights and experimental experience for cost-effective and controllable production of MOF-based catalysts but also offers ideas for the development of future electrocatalysts by exploring the exposure and protection of active site using MOFs materials.

Determination of seven phenoxy carboxylic acid herbicides in water using dispersive solid phase extraction coupled with ultra-high performance liquid chromatography-tandem mass spectrometry based on metal-organic framework composite aerogel

Phenoxy carboxylic acid herbicides (PCAs) are difficult to degrade and, thus, pose significant threats to the environment and human health. The limit for 2,4-dichlorophenoxyacetic acid is 30 μg/L in China's standards for drinking water quality, 70 μg/L in the United States' drinking water standards, and 30 μg/L in the World Health Organization's guidelines for drinking water quality. Therefore, the development of an effective detection method for trace PCAs in water is a crucial endeavor. Metal-organic frameworks (MOFs) are novel porous materials that possess advantages such as a large specific surface area, adjustable pore size, and abundant active sites. They exhibit excellent adsorption capability for various compounds. However, the applications of MOFs as adsorbents are limited. For example, the process of isolating powdered MOFs from aqueous solutions is laborious, and microporous MOFs exhibit limited surface affinity, which decreases their mass transfer efficiency in the liquid phase. MOF crystals can be embedded in a substrate to overcome these limitations. Aerogels are obtained by drying hydrogels, which are hydrophilic polymers with a three-dimensional crosslinked network structure. Spongy aerogel materials exhibit unique structural properties such as high porosity, large pore volume, ultralow density, and easy tailorability. When MOFs are combined with an aerogel, their efficient and selective adsorption properties are preserved. In addition, MOF aerogels exhibit a hierarchical porous structure, which enhances the affinity and mass transfer efficiency of the MOF for target molecules. At present, MOF aerogels are primarily prepared by freeze-drying or using supercritical carbon dioxide. These drying processes require significant amounts of energy and time. Hence, the development of greener and more efficient methods to prepare skeleton aerogels is urgently needed. In this study, we prepared an environment-friendly aerogel at ambient temperature and pressure without the use of specialized drying equipment. This ambient-dried MOF composite aerogel was then used for the dispersive solid phase extraction (DSPE) of seven PCAs from environmental water, followed by ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). The key parameters affecting the efficiency of DSPE, including the extraction conditions, ratio of MIL-101(Fe)-NH2 to sodium alginate, pH of the aqueous samples, extraction time, ionic strength (salinity), and elution conditions, such as the elution solvent ratio, elution time, and elution volume, were investigated to obtain optimal extraction efficiency. The adsorbent could adsorb the target contaminants within 12 min, and the analytes could be completely desorbed within 30 s by elution with 4 mL of 1.5% (v/v) formic acid in methanol solution. The water samples could be analyzed without pH adjustment. The main adsorption mechanisms were electrostatic interactions and π-π conjugation. Thus, a new method based on MOF aerogels coupled with UHPLC-MS/MS was developed for the determination of the seven PCA residues in water. The calibration curves for the seven PCAs showed good linearity (r2≥0.9986), with limits of detection (LODs) and quantification (LOQs) ranging from 0.30 to 1.52 ng/L and from 1.00 to 5.00 ng/L, respectively. Good intra- and inter-day precision values of 6.5%-17.1% and 7.4%-19.4%, respectively, were achieved under low (8 ng/L), medium (80 ng/L), and high (800 ng/L) spiking levels. The developed method was applied to the detection of PCAs in surface water, seawater, and waste leachate, and the detected mass concentrations ranged from 0.6 to 19.3 ng/L. Spiked recovery experiments were conducted at mass concentrations of 8, 80, and 800 ng/L, and the recoveries ranged from 61.7% to 120.3%. The proposed method demonstrates good sensitivity, precision, and accuracy, and has potential applications in the detection of trace PCAs in environmental water.

A general flame aerosol route to kinetically stabilized metal-organic frameworks

Metal-organic frameworks (MOFs) are highly attractive porous materials with applications spanning the fields of chemistry, physics, biology, and engineering. Their exceptional porosity and structural flexibility have led to widespread use in catalysis, separation, biomedicine, and electrochemistry. Currently, most MOFs are synthesized under equilibrium liquid-phase reaction conditions. Here we show a general and versatile non-equilibrium flame aerosol synthesis of MOFs, in which rapid kinetics of MOF formation yields two distinct classes of MOFs, nano-crystalline MOFs and amorphous MOFs. A key advantage of this far-from-equilibrium synthesis is integration of different metal cations within a single MOF phase, even when this is thermodynamically unfavorable. This can, for example, produce single-atom catalysts and bimetallic MOFs of arbitrary metal pairs. Moreover, we demonstrate that dopant metals (e.g., Pt, Pd) can be exsolved from the MOF framework by reduction, forming nanoclusters anchored on the MOF. A prototypical example of such a material exhibited outstanding performance as a CO oxidation catalyst. This general synthesis route opens new opportunities in MOF design and applications across diverse fields and is inherently scalable for continuous production at industrial scales.

Metal‐Organic Frameworks (MOFs) for Glucose Sensing: Advancing Non‐Invasive Detection Strategies in Diabetes Management

Effective glucose monitoring is critical for managing diabetes and preventing its associated complications. While commercial glucose monitoring devices predominantly rely on blood samples, emerging research focuses on detecting glucose in alternative biofluids, harnessing advanced nanomaterials. Among these, Metal‐Organic Frameworks (MOFs), composed of metal ions and organic ligands, have garnered significant attention due to their unique properties, including tunable porosity, high surface area, and abundant active sites conducive to glucose interaction. MOFs present a versatile platform for glucose sensing, offering potential in both enzymatic and non‐enzymatic detection methods. This review delves into the recent advancements in MOFs‐based electrochemical glucose sensors, providing a comprehensive analysis of various MOFs and their composites as electrode materials. The discussion highlights the structural attributes, functionalization strategies, and electrochemical performance of MOFs in glucose sensing, emphasizing their role in the development of next‐generation, non‐invasive glucose monitoring technologies. The review provides a comprehensive overview on the application of MOFs and MOFs‐based composites in both enzymatic and non‐enzymatic electrochemical‐based glucose sensing and highlights the synthesis, mechanism, functionalization and development in the detection strategy of MOFs in glucose sensing.

Metal‐organic frameworks‐based nanomedicines to promote cancer immunotherapy: Recent advances and future directions

AbstractCancer immunotherapy uses the body's immune system to fight tumors by restoring natural antitumor responses. Metal‐organic frameworks (MOFs), characterized by their unique crystalline porous structures formed from metal ions linked by organic ligands, offer a promising solution. Recent studies have unveiled the potential of MOFs in cancer immunotherapy. The exceptional porosity and surface area, coupled with their extraordinary thermal and chemical stability, bring significant advantages for efficient drug loading and delivery of immunotherapeutic agents. The adaptability of MOFs further enhances the controlled release of immunotherapeutic drugs within target cells and increases tumor sensitivity to other therapies such as photodynamic, photothermal, and radiotherapy. This multifunctional carrier contributes to modulating the tumor microenvironment and reactivating antitumor immunity, providing a comprehensive strategy for cancer treatment. In this review, we summarize the applications of MOFs in immune checkpoint blockade, immunomodulator delivery, and cancer vaccine delivery, and discuss existing challenges in their use for immunotherapy. This discussion aims to offer insights for developing better treatments and enhancing the efficacy of immunotherapy.

Applications of Metal-Organic Frameworks (MOFs) in Drug Delivery, Biosensing, and Therapy: A Comprehensive Review.

The porous materials known as metal-organic frameworks (MOFs) stand out for their enormous surface area, adaptable pore size and shape, and structural variety. These characteristics make them well-suited for various applications, especially in healthcare. This review thoroughly summarizes recent studies on the use of MOFs in drug delivery, biosensing, and therapeutics. MOFs may encapsulate medications, target certain cells or tissues, and regulate their release over time. Additionally, MOFs have the potential to be used in biosensing applications, allowing for the selective detection of chemical and biological substances. MOFs' optical or electrical characteristics may be modified to make biosensors that track physiological data. MOFs show potential for targeted drug delivery and the regulated release of therapeutic substances in cancer treatment. In addition, they may work as potent antibacterial agents, providing a less dangerous option than traditional antibiotics that increase antibiotic resistance. For practical applications, further research is required as well as more consideration for the problems with toxicity and biocompatibility. In addition to addressing the difficulties and promising possibilities in this area, this study intends to provide insights into the potential of MOFs in healthcare for drug delivery, biosensing, and treatment. Despite several essential reviews in this area, it was necessary to look into the most recent research on drug delivery, biosensing, and therapy as a combined concept.

An efficient peroxymonosulfate activator derived from metal-organic frameworks: The application of Cu, Mg co-doping strategy

The application of metal-organic frameworks (MOFs)-based catalysts in Fenton-like reactions attracts increasing attention, however, improving the efficiency of these catalysts remains a challenge. Herein, a highly efficient peroxymonosulfate (PMS) activator (CuMg@Fe-MOFs-500) derived from MOFs was successfully synthesized. The results indicated that the Cu and Mg co-doping strategy employed in the fabrication of CuMg@Fe-MOFs-500 significantly enhanced the PMS activation performance, achieving a tetracycline (TC) degradation efficiency of 96.8 % within 60 min. The incorporation of the doped Mg and Cu significantly increased the contents of the oxygen vacancy (OV) and low-valent copper (Cu0 and Cu+), respectively. The interaction between the OV and Cu0/Cu+ became a key factor during the PMS decomposition process. Furthermore, for the first time, the OV content was observed to be positively and negatively linearly correlated with the reaction rate constant (k) and the charge transfer resistance (Rct) of the prepared PMS activators, respectively. Quenching experiments and electron paramagnetic resonance (EPR) tests demonstrated that the predominant reactive species generated during the PMS activation process were SO4•-, •OH, O2•-, and 1O2. It was also shown that the 1O2 primarily originated from O2•- disproportionation, and a self-quenching process between SO4•- and •OH was also observed. The intermediates produced during pollutant degradation induced by PMS-based Fenton-Like reaction exhibited reduced toxicity, as demonstrated by ecotoxicity analysis. This study presented a novel approach for the fabrication of catalyst derived from bimetallic doped MOFs, characterized by a high OV content, for the application in PMS-based Fenton-like reactions.

A smartphone-assisted test paper fluorescence sensing platform for visual detection of α-Ketoglutaric acid based on Metal-Organic frameworks

Developing an accurate, sensitive and visual strategy for quickly identifying biomarkers α-ketoglutaric acid (α-KA) is crucial for early disease diagnosis. Herein, we introduce a new fluorescence material, Eu3+@COMOC-4, synthesized by post-synthesis modification of a lanthanide-functionalized metal–organic frameworks (MOFs). This material serves as a visual fluorescence sensor to detect α-KA, with a distinct fluorescence response. Particularly, the sensor exhibits many advantages, such as good selectivity, high sensitivity and quick response. The quenching mechanism between the sensor and α-KA was also illustrated in detail. More significantly, a smartphone-integrated test paper fluorescence sensing platform was further developed for α-KA detection, which enables sensitive, real-time, and visual detection of α-KA. This work provides a sensitive and real-time biomarker detection strategy, which is expected to expand the application of MOFs in significant fields.

Optimizing ligand-to-metal charge transfer in metal–organic frameworks to enhance photocatalytic performance

Metal-organic frameworks (MOFs) have been widely investigated as active photocatalytic material for energy conversion and environmental purification. This review meticulously examines the charge transfer mechanisms within MOFs upon photoexcitation, with a particular emphasis on ligand-to-metal charge transfer (LMCT) and metal-to-ligand charge transfer (MLCT). These processes are essential for the generation and maintenance of effective charge separation, wherein LMCT is especially critical for the photocatalytic applications of MOFs. The analysis begins with an exploration of the charge transfer mechanisms within the MOFs’ structure, assessing the impact of various factors on LMCT, including the metal center, ligand structure, overall spatial configuration and reaction environment. Furthermore, the review provides an in-depth exploration of the advantages and applications of LMCT in photocatalysis. It concludes with an outlook on the future development of LMCT in the field of photocatalysis, underscoring its transformative potential with ongoing research and innovation.

Overview of Liquid Sample Preparation Techniques for Analysis, Using Metal-Organic Frameworks as Sorbents.

The preparation of samples for instrumental analysis is the most essential and time-consuming stage of the entire analytical process; it also has the greatest impact on the analysis results. Concentrating the sample, changing its matrix, and removing interferents are often necessary. Techniques for preparing samples for analysis are constantly being developed and modified to meet new challenges, facilitate work, and enable the determination of analytes in the most comprehensive concentration range possible. This paper focuses on using metal-organic frameworks (MOFs) as sorbents in the most popular techniques for preparing liquid samples for analysis, based on liquid-solid extraction. An increase in interest in MOFs-type materials has been observed for about 20 years, mainly due to their sorption properties, resulting, among others, from the high specific surface area, tunable pore size, and the theoretically wide possibility of their modification. This paper presents certain advantages and disadvantages of the most popular sample preparation techniques based on liquid-solid extraction, the newest trends in the application of MOFs as sorbents in those techniques, and, most importantly, presents the reader with a summary, which a specific technique and MOF for the desired application. To make a tailor-made and well-informed choice as to the extraction technique.

Metal-Organic Frameworks for Sustainable Crop Disease Management: Current Applications, Mechanistic Insights, and Future Challenges.

Efficient management of crop diseases and yield enhancement are essential for addressing the increasing food demands due to global population growth. Metal-organic frameworks (MOFs), which have rapidly evolved throughout the 21st century, are notable for their vast surface area, porosity, and adaptability, establishing them as highly effective vehicles for controlled drug delivery. This review methodically categorizes common MOFs employed in crop disease management and details their effectiveness against various pathogens. Additionally, by critically evaluating existing research, it outlines strategic approaches for the design of drug-delivery MOFs and explains the mechanisms through which MOFs enhance disease resistance. Finally, this paper identifies the current challenges in MOF research for crop disease management and suggests directions for future research. Through this in-depth review, the paper seeks to enrich the understanding of MOFs applications in crop disease management and offers valuable insights for researchers and practitioners.

Tribological application of oleylamine incorporated flexible metal-organic frameworks MIL-88A based self-lubricating composite

To expand the application of MOFs in self-lubricating composites, we synthesized metal organic frameworks (MOFs) MIL-88A tailored for oleylamine (Ole) adsorption, resulting in the Ole@MIL-88A composite with oleylamine adsorbed. This material was incorporated into epoxy resin (EP) to form EP/Ole@MIL-88A composites. The composites were firstly applied to axle sleeves for tribological evaluations. The tests revealed that the EP/10 wt% Ole@MIL-88A composite had the lowest COF (0.137), with a 65.9 % decrease compared to pure EP. The EP/8 wt% Ole@MIL-88A displayed the lowest wear depth, with a 68.4 % reduction compared to pure EP. This research signifies the initial application of MOF-based self-lubricating composites to mechanical components and engineering evaluations, laying the groundwork for their design in future industrial settings.

Exploring Synthesis Strategies and Interactions between MOFs and Drugs for Controlled Drug Loading and Release, Characterizing Interactions through Advanced Techniques.

This study explores various aspects of Metal-Organic Frameworks (MOFs), focusing on synthesis techniques to adjust pore size and key ligands and metals for crafting carrier MOFs. It investigates MOF-drug interactions, including hydrogen bonding, van der Waals, and electrostatic interactions, along with kinetic studies. The multifaceted applications of MOFs in drug delivery systems are elucidated. The morphology and structure of MOFs are intricately linked to synthesis methodology, impacting attributes like crystallinity, porosity, and surface area. Hydrothermal synthesis yields MOFs with high crystallinity, suitable for catalytic applications, while solvothermal synthesis generates MOFs with increased porosity, ideal for gas and liquid adsorption. Understanding MOF-drug interactions is crucial for optimizing drug delivery, affecting charge capacity, stability, and therapeutic efficacy. Kinetic studies determine drug release rates and uniformity, vital for controlled drug delivery. Overall, comprehending drug-MOF interactions and kinetics is essential for developing effective and controllable drug delivery systems.

Customized Nano‐Confinement Effects of Metal‐Organic Frameworks for High‐Performance Lithium‐Sulfur Batteries

Lithium‐sulfur batteries (LSBs) are considered one of the most promising next‐generation energy storage devices due to their significant theoretical energy density and high specific capacity of sulfur cathode. However, several critical challenges still must be addressed for practical application. The shuttle effect and sluggish redox kinetics severely impact their performance. Metal‐organic frameworks (MOFs) have garnered significant interest attributed to their high structural tunability. Their ability to nano‐confine lithium polysulfides (LiPSs) can be precisely controlled at the molecular level by regulating metal centers and organic ligands, thereby suppressing the shuttle effect and improving the electrochemical performance of LSBs. This review summarizes the nano‐confinement effects of MOFs in LSBs, and the discussion is divided into the selective confinement and nano‐confined adsorption by inert MOFs, as well as nano‐confined catalysis facilitated by catalytically active MOFs. Furthermore, the existing challenges and future prospects for application of MOFs in LSBs are proposed.

Emerging insights into the application of metal-organic framework (MOF)-based materials for electrochemical heavy metal ion detection

Heavy metal ions are one of the main sources of water pollution, which has become a major global problem. Given the growing need for heavy metal ion detection, electrochemical sensor stands out for its high sensitivity and efficiency. Metal-organic frameworks (MOFs) have garnered much interest as electrode modifiers for electrochemical detection of heavy metal ions owing to their significant specific surface area, tailored pore size, and catalytic activity. This review summarizes the progress of MOF-based materials, including pristine MOFs and MOF composites, in the electrochemical detection of various heavy metal ions. The synthetic methods of pristine MOFs, the detection mechanisms of heavy metal ions and the modification strategies of MOFs are introduced. Besides, the diverse applications of MOF-based materials in detecting both single and multiple heavy metal ions are presented. Furthermore, we present the current challenges and prospects for MOF-based materials in electrochemical heavy metal ion detection.

Stability-enhanced (Cu-, Zn-)MOFs via (Cu, Zn)S composite strategy: A promising approach for oil-water separation

The application of metal-organic frameworks (MOFs) in the field of oil-water separation is developing rapidly, but the challenges of poor water stability, poor scalability and durability still limit its practical application. In this study, two environmentally friendly and non-toxic superhydrophobic (Cu, Zn)S/(Cu-, Zn-)MOFs@stearic acid (CuS/Cu-MOFs@SA and ZnS/Zn-MOFs@SA) coatings were successfully prepared by hydrothermal method combined with dip coating method, with a water contact angle (WCA) of >165°. Through the synergistic effect with stearic acid (SA), the (Cu-, Zn-)MOFs coating composited with CuS and ZnS exhibits excellent durability in extreme environments. This synergistic effect significantly improves the mechanical stability and durability of the coating, allowing it to maintain a WCA of >155° after friction, kneading, tape stripping and ultrasonic treatment. However, CuS/Cu-MOFs@SA coating is significantly superior to ZnS/Zn-MOFs@SA coating in terms of chemical stability (acid-base-salt environment) and self-cleaning ability due to the different ligands used in the preparation process and the formation of particle structure. Significantly improved its durability and reliability in oil-water separation. The separation efficiency of the coating is as high as 98.7 %, and it remains above 97.8 % after 12 times of repeated use. This study provides a new strategy and important reference for the development of superhydrophobic MOFs coatings and oil-water separation materials with high stability, wear resistance and corrosion resistance.

The utility of MOF-based materials in direct air capture (DAC) application to ppm-level CO2

Metal-organic frameworks (MOFs) are well-suited materials for CO2 removal and have robust capture capacity and selectivity. Although the adsorption of CO2 in MOFs has been studied, the implementation of ppm-level CO2 uptake in MOFs and the effects of the pore size and charge have not been fully explored. We performed grand canonical Monte Carlo (GCMC) simulations combined with the Density Functional Theory plus U (DFT + U) charge method to investigate MOF screening for ppm-level CO2 uptake and its application in a direct air capture (DAC) system. Three types of MOFs containing eight members were studied: i.e., ZIF-68, 69, 70; UiO-66, 67, 68; CAU-10; and MIL-125. The pore landscape characterization, electrostatic field-induced enhancement, and preferential binding sites of these MOFs were examined for CO2 capture. MOFs with pore limited diameters (PLD) 1.5 times the size of CO2 molecules and with large cavity diameters (LCD) smaller than 10 Å exhibit robust confinement capacity. Polar functional groups and metal ions dominate the electrostatic contributions and subsequently enhance the surface adhesion of CO2 molecules. For a given framework, favorable CO2 binding occurs in the following order: small pores/cages > polar functional group/metal ions > larger pores/cages. ZIF-69 which comprises smaller pores (7.5 Å) and robust polar functional groups (–Cl) collectively enhances CO2 capture; thus, ZIF-69 outperforms other MOFs; the performance of ZIF-69 is followed by that of CAU-10 which has an optimal pore size of 6 Å. These findings are of fundamental and practical importance for the application of MOFs in DAC technologies for CO2 removal.