Metal-organic Framework Materials Research Articles

Multivariate mesoporous MOFs with regulatable hydrophilic/hydrophobic surfaces as a versatile platform for enzyme immobilization

Zeolitic imidazole frameworks materials-8 (ZIF-8), a member of the metal-organic framework (MOFs) series, have been extensively used as a host matrix for enzyme immobilization. However, the microporous structure and hydrophobicity, as well as the protonation of the precursor 2-methylimidazole (2-MeIm) of ZIF-8, remain considerable challenges in maintaining the activity of immobilized enzymes. Here, novel multivariate mesoporous MOFs (mMOFs) with regulatable hydrophilic/hydrophobic surfaces were designed by the multivariate competitive strategy and pore modification engineering. 3-Methyl-1H-1,2,4-triazole (3-MTZ) and 5-methyltetrazole (5-MTA) were employed to partially replace 2-MeIm. These were then combined with zinc sulfate heptahydrate (soft templates) to yield mMOFs in a methanol solution. As a proof-of-concept application, we used mMOFs as carriers for enzyme immobilization and investigated the properties of the immobilized enzymes. Benefiting from their mesoporous structure, hydrophilic surface, and improved microenvironment, multivariate mMOFs exhibit a strong ability to stabilize enzyme conformation and increase enzyme activity compared with traditional ZIF-8. Our study offers an avenue for the controllable preparation of well-designed MOF structures, which will further broaden the application opportunities of MOF materials for enzyme immobilization.

Optimization of cobalt-based MOFs for super-capacitor electrode materials of new energy vehicle

Super-capacitors (SCs), as new energy conversion storage elements, have attracted much attention, but there is still a research gap in the design of electrode materials. In this study, the optimization scheme of Metal-Organic Frameworks (MOFs) and cobalt-based MOF composites as electrode materials for SCs in new energy vehicles is explored, and a series of experiments are conducted to evaluate their performance. Scanning Electron Microscope (SEM) images reveal that the cobalt-based MOF composites have a surface morphology of particles with uniform distribution. The electrochemical performance test results show that the specific capacitance of the cobalt-based MOF composites is much higher than the sum of the two individual electrode materials and presents a remarkable increase with the scanning rate. Additionally, in the constant current charge-discharge test, cobalt-based MOF composites exhibit the longest charge-discharge time and good symmetry. Electrolyte particle contact tests for samples at different preparation temperatures display that high-temperature samples have better structural stability and electrolyte ion contact. In Cyclic Voltammetry (CV) and Galvanostatic Charge Discharge (GCD) tests, the 250 °C sample demonstrates the best electrochemical properties and the highest specific capacitance (269 F/g). Moreover, as the current density increases, the specific capacitance of the 600 °C sample decreases at a lower rate, showing stronger stability. However, the use of cobalt-based MOF materials may pose environmental and safety risks, such as the environmental impact of cobalt resource mining, instability under high-temperature conditions, and the possible production of hazardous substances. Therefore, these factors need to be fully considered when designing and using SCs to ensure the environmental friendliness and safety of cobalt-based MOFs. These results provide an important reference for selecting and optimizing electrode materials for SCs in new energy vehicles. Furthermore, this study offers research suggestions for improving new energy materials, filling the research gaps in related fields, and supporting the further development of SC technology.

Comparing The Catalytic Activity of Mg-BTC Metal Organic Framework and Post Synthetically Modified (TiO2 @ Mg-BTC) Metal Organic Framework for Cyanosilylation of Aldehydes

Metal organic frameworks (MOFs) are an emerging class of porous crystalline hybrid materials synthesised by the coordination of inorganic connectors and organic linkers, which has numerous potential applications in various fields. Here we report a comparative study on Mg-BTC MOF and TiO @Mg-BTC MOF as a heterogeneous catalyst. Mg-BTC MOF was synthesised by solvothermal method and subjected to comparative study with its post synthetically modified (PSM) counterpart to understand their catalytic behaviour for cyanosilylation of aldehydes. The synthesised Mg-BTC MOF and TiO @Mg-BTC MOF were characterised by powder XRD, BET surface area, SEM, FT-IR, TGA techniques. A detailed characterization study was performed to understand the correlation between catalytic activity and morphology of the assynthesized MOF and PSM-MOF. The catalytic activity of the hybrid materials were evaluated by GC-MS analysis. The results of the catalytic reactions revealed that post synthetically modified (TiO @Mg-BTC) MOF exhibited significantly higher catalytic activity compared to Mg-BTC MOF. The enhanced catalytic efficiency is due to the incorporation of TiO nanoparticles, which provides active sites for catalytic reactions under heterogeneous conditions. Even after repeated recycling and reuse, the catalytic ability of the catalyst retains. The impact of TiO on the framework shows variation in texture, surface area, thermal stability and catalytic behaviour on the MOF materials. Thus, our study emphasizes

Facile preparation of ZIF-67 on TiO2 and enhancement photocathodic protection for 316L stainless steel

Photocathodic protection (PCP) anticorrosion using sunlight is a green and sustainable technology. However, the ease of carriers compounding and the low light utilization are still the main restraints to its development. To develop an effective photoanode, a metal-organic framework (MOF, i.e., ZIF-67) material is electrodeposited and grown in-situ on TiO2 nanorods. The morphological structure, light absorption properties, photoelectrochemical properties and cathodic protection principle of ZIF-67/TiO2 photoanode are analysed by SEM, PL, I-V and EIS. The material characterization and light absorption characteristics show that the photoanode has good light absorption performance and higher electron hole separation efficiency. Photoelectrochemical test shows that ZIF-67/TiO2 photoanode has excellent photocathodic protection for 316L stainless steel (316L SS). ZTRs-60 has the optimal protection effect. Under simulated sunlight, the OCP of 316L SS coupled ZTRs-60 is -0.41 V vs. Ag/AgCl, and the current density of the I-t curve can reach 20 μA/cm2. EIS and Tafel tests show that the photogenerated electrons transfer to the stainless steel surface, which promotes the cathode polarization process and alleviates the metal corrosion.

Enhanced asymmetric supercapacitor performance via facile construction of Cu-MOF@Co(OH)2 heterostructure

Integrating metal-organic frameworks (MOFs) with transition hydroxides has the potential to enhance the inadequate electronic conductivity and address the slow diffusion of MOF materials in electrochemical applications. Herein, we synthesized a 2D Cu-MOF and successfully prepared a Cu-MOF@Co(OH)2 heterostructure using a one-step hydrothermal method on a Co(OH)2/NF (nickel foam) substrate. The hybrid Cu-MOF@Co(OH)2 material exhibits high electrochemical reactivity, resulting in enhanced pseudocapacitor performance, with a specific capacitance of 2039.8 mF cm−2 at a current density of 1.0 mA cm−2. In addition, an asymmetric two-electrode cell was constructed using Cu-MOF@Co(OH)2/NF and activated carbon (AC)/NF, exhibiting a specific capacitance of 444.5 mF cm−2 at a current density of 1.0 mA cm−2, and demonstrating decent cycling durability with 90.1 % retention after 2000 cycles.

Efficient Proton-exchange Membrane Fuel Cell Performance of Atomic Fe Sites via p-d Hybridization with Al Dopants.

Orbital hybridization to regulate the electronic structures and surface chemisorption properties of transition metals is of great importance for boosting the oxygen reduction reaction (ORR) in proton-exchange membrane fuel cells (PEMFCs). Herein, we developed a core-shell rambutan-like nanocarbon catalyst (FeAl-RNC) with atomically dispersed Fe-Al atom pairs from metal-organic framework (MOF) material. Experimental and theoretical results demonstrate that the strong p-d orbital hybridization between Al and Fe results in an asymmetric electron distribution with moderate adsorption strength of oxygen intermediates, rendering enhanced intrinsic ORR activity. Additionally, the core-shell rambutan-like structure of FeAl-RNC with abundant micropores and macropores can enhance the density of active sites, stability, and transport pathways in PEMFC. The FeAl-RNC-based PEMFC achieves excellent activity (68.4 mA cm-2 at 0.9 V), high peak power (1.05 W cm-2), and good stability with only 7% current loss after 100 h at 0.7 V under H2-O2 condition.

Copper/cobalt metal-organic framework composites for advanced anode material of lithium-ion battery

In this paper, two new types of metal-organic frameworks (MOFs) materials, namely Cu-IM and Co-MOF, have been successfully applied to the anode of lithium-ion batteries with LiPF6 (EC: DMC = 1:1, volume) electrolyte additive. Cu-IM and Co-MOF employed imidazole (IM) and 2-methylimidazole (2-MeIM) as organic ligands, respectively. The results revealed the synthesized MOFs exhibited high initial discharge specific capacities (Cu-IM: 1964.5 mAh g−1, Co-MOF: 1423.3 mAh g−1) as well as low internal resistances (Cu-IM: 146 Ω; Co-MOF: 236 Ω). To alleviate the issue of capacity decay in single MOFs, we attempted the dual-MOFs materials through the rational design of interfacial/surface properties and microstructure. Compared to Cu-IM, the prepared Cu-IM/Co-MOF composites have a higher specific surface area and pore volume. Furthermore, the charge transfer resistance of Cu-IM/Co-MOF composites (141 Ω) was lower than that of Cu-IM and Co-MOF respectively. After a heat treatment to Cu-IM/Co-MOF composites, the electrochemical performance of obtained Cu-IM/Co-MOF 250 dual-MOFs composites have been significantly improved. The Cu-IM/Co-MOF 250 dual-MOFs composites demonstrated excellent cycling stability and high discharge specific capacities at various current densities. The composites displayed stable discharge specific capacity retention of 834 mAh g−1 (50 mA g−1, 75 cycles), 710.5 mAh g−1 (200 mA g−1, 50 cycles), and 392.5 mAh g−1 (500 mA g−1, 50 cycles), highlighting their promising performance for energy storage applications. The synthesized Cu-IM/Co-MOF 250 dual-MOFs composites demonstrates exceptional cycling performance and rate capability, implying that it has the promising prospects as anode material for lithium-ion batteries.

Recent advances in small-angle scattering techniques for MOF colloidal materials

This paper reviews the recent progress of small angle scattering (SAS) techniques, mainly including X-ray small angle scattering technique (SAXS) and neutron small angle scattering (SANS) technique, in the study of metal-organic framework (MOF) colloidal materials (CMOFs). First, we introduce the application research of SAXS technique in pristine MOFs materials, and review the studies on synthesis mechanism of MOF materials, the pore structures and fractal characteristics, as well as the spatial distribution and morphological evolution of foreign molecules in MOF composites and MOF-derived materials. Then, the applications of SANS technique in MOFs are summarized, with emphasis on SANS data processing method, structure modeling and quantitative structural information extraction. Finally, the characteristics and developments of SAS techniques are commented and prospected. It can be found that most studies on MOF materials with SAS techniques focus mainly on nanoporous structure characterization and the evolution of pore structures, or the spatial distribution of other foreign molecules loaded in MOFs. Indeed, SAS techniques take an irreplaceable role in revealing the structure and evolution of nanopores in CMOFs. We expect that this paper will help to understand the research status of SAS techniques on MOF materials and better to apply SAS techniques to conduct further research on MOF and related materials.

Bimetal-Organic Frameworks Incorporating Both Hard and Soft Base Active Sites for Heavy Metal Ion Capture.

The design and synthesis of stable porous materials capable of removing both hard and soft metal ions pose a significant challenge. In this study, a novel metal-organic framework (MOF) adsorbent named CdK-m-COTTTB was developed. This MOF material was constructed using sulfur-rich m-cyclooctatetrathiophene-tetrabenzoate (m-H4COTTTB) as the organic ligand and oxygen-rich bimetallic clusters as the inorganic nodes. The incorporation of both soft and hard base units within the MOF structure enables effective removal of various heavy metal ions, including both soft and hard acid species. In single-component experiments, the adsorption capacity of CdK-m-COTTTB for Pb2+, Tb3+, and Zr4+ ions reached levels of 636.94, 432.90, and 357.14 mg·g-1, respectively, which is comparable to specific MOF absorbents. The rapid adsorption process was found to be chemisorption. Furthermore, CdK-m-COTTTB exhibited the capability to remove at least 12 different metal ions in both separate and multicomponent solutions. The material demonstrated excellent acid-base stability and renewability, which are advantageous for practical applications. CdK-m-COTTTB represents the first reported pristine MOF material for the removal of both hard and soft acid metal ions. This work serves as inspiration for the design and synthesis of porous crystalline materials that can efficiently remove diverse heavy metal pollutants.

A Short Review of Advances in MOF Glass Membranes for Gas Adsorption and Separation.

The phenomenon of melting in metal-organic frameworks (MOFs) has recently garnered attention. Crystalline MOF materials can be transformed into an amorphous glassy state through melt-quenching treatment. The resulting MOF glass structure eliminates grain boundaries and retains short-range order while exhibiting long-range disorder. Based on these properties, it emerges as a promising candidate for high-performance separation membranes. MOF glass membranes exhibit permanent and accessible porosity, allowing for selective adsorption of different gas species. This review summarizes the melting mechanism of MOFs and explores the impact of ligands and metal ions on glassy MOFs. Additionally, it presents an analysis of the diverse classes of MOF glass composites, outlining their structures and properties, which are conducive to gas adsorption and separation. The absence of inter-crystalline defects in the structures, coupled with their distinctive mechanical properties, renders them highly promising for industrial gas separation applications. Furthermore, this review provides a summary of recent research on MOF glass composite membranes for gas adsorption and separation. It also addresses the challenges associated with membrane production and suggests future research directions.

A (3,12)-connected metal-organic framework based on hexanuclear zinc cluster for iodine capture

The adsorption of discharged radioactive iodine is considered an important method to address this environmental problem. Metal-organic framework (MOF) materials are expected to be potential materials for capturing iodine. In this work, a new zinc-based MOF, namely [Zn6(OH)6(DMTDC)3(TPB)]·0.5DMF (JOU-31), was successfully prepared under solvothermal condition (H2DMTDC = 3,4-dimethylthieno [2,3-b]thiophene-2,5-dicarboxylic acid, TPB = 1,3,5-tris(4-pyridyl)benzene, DMF = N,N-Dimethylformamide). Structural analyses revealed that JOU-31 was a three-dimensional porous structure based on hexanuclear zinc-oxide clusters. Topologically, the framework of JOU-31 can be simplified to a (3,12)-connected net with new Schläfli symbol of {43·630}{43}2. Due to its large specific surface area, abundant electron-rich N/S sites, and high stability, JOU-31 was applied to capture iodine. The saturated iodine adsorption capacity of JOU-31 in n-hexane solution was 822 mg g−1. In addition, the interaction mechanism between JOU-31 and the adsorbed iodine was further explored in detail. This work provides a valuable clue for the preparation of new MOFs for iodine adsorption.

Synthesis and characterization of a β-cyclodextrin-MOF-based porous hydrogel for efficient adsorption of Au3+, Ag+, and Pb2+ ions

Wastewater containing heavy metal ions produced by electroplating, smelting and other industries poses a threat to human safety. Recently, metal–organic frameworks (MOFs) have emerged as porous crystalline adsorbents for the removal of heavy metal ions. Starch-derived cyclodextrins (CDs), a series of cyclic oligosaccharides, have been explored for fabrication of cost-efficient MOF materials. However, the coordination bonds in CD-based MOFs can be destroyed by water, which limits their application as absorbent materials for the removal of heavy metal ions from wastewater. In this work, a β-CD-MOF-based porous hydrogel was developed by incorporating a crosslinked hydrogel network based on acrylic acid (AA) and N,N’-methylenebis(acrylamide) (MBA) monomers into a β-CD-based MOF structure. The synthesized porous hydrogel, denoted A/M−CDMOF−gel, not only showed enhanced structural stability but also exhibited excellent properties for simultaneous adsorption of Au3+, Ag+, and Pb2+ ions. A kinetic study revealed that the A/M−CDMOF−gel had a satisfactory binding rate within 60 min of contact, and the higher fit coefficient from the pseudo-second-order model indicated its chemical adsorption property. Moreover, according to the Langmuir isotherm model fitting results, the maximum capacity of the A/M−CDMOF−gel reached 316.4, 60.9, and 414.2 mg/g for Au3+, Ag+, and Pb2+, respectively. Therefore, the regenerable A/M−CDMOF−gel adsorbent is expected to provide ideas for the development of renewable absorbent materials in the field of wastewater treatment and remediation.

Defect Engineering Strategy for Superior Integration of Metal-Organic Framework and Halide Perovskite as a Fluorescence Sensing Material.

Combining halide perovskite quantum dots (QDs) and metal-organic frameworks (MOFs) material is challenging when the QDs' size is larger than the MOFs' nanopores. Here, we adopted a simple defect engineering approach to increase the size of zeolitic imidazolate framework 90 (ZIF-90)'s pores size to better load CH3NH3PbBr3 perovskite QDs. This defect structure effect can be easily achieved by adjusting the metal-to-ligand ratio throughout the ZIF-90 synthesis process. The QDs are then grown in the defective structure, resulting in a hybrid ZIF-90-perovskite (ZP) composite. The QDs in ZP composites occupied the gap of 10-18 nm defective ZIF-90 crystal and interestingly isolated the QDs with high stability in aqueous solution. We also investigated the relationship between defect engineering and fluorescence sensing, finding that the aqueous Cu2+ ion concentration was directly correlated to defective ZIF-90 and ZP composites. We also found that the role of the O-Cu coordination bonds and CH3NHCu+ species formation in the materials when they reacted with Cu2+ was responsible for this relationship. Finally, this strategy was successful in developing Cu2+ ion fluorescence sensing in water with better selectivity and sensitivity.

Assembly of Amorphizing Porous Bimetallic Metal‐Organic Frameworks Spheres with Zn─O─Fe Cluster and Coordination Deficiency via Ligand Competition for Efficient Electro‐Fenton Catalysis

AbstractElectro‐Fenton process stands out as a highly promising approach for generating reactive oxygen‐containing radicals to address the escalating issue of environmental pollution. However, the long‐term goal of application necessitates ongoing pursuit of high‐quality catalysts with both sufficient activity and stability. Herein, a general route is reported for large‐scale synthesis of amorphizing porous bimetallic metal‐organic framework (MOF) spheres with Zn─O─Fe structure and coordination deficiency through facile and low‐cost synthesis of ligand competition. Assisted by a coordination modulator, deprotonation of terephthalic acid is accelerated and rapid synthesis of amorphous bimetallic MOF spheres is successfully achieved at room temperature. As inactive metal Zn is introduced into metal clusters of MOFs, the cycling efficiency of Fe3+/Fe2+ is improved and a secondary building unit of Zn─O─Fe is constructed, greatly accelerating electron conduction rate. Compared to crystalline spindle cMIL‐88B(Fe2Zn) by traditional solvothermal route, amorphous aMIL‐88B(Fe2Zn) has a unique spherical porous structure with larger surface area, higher conductivity, and more exposed active sites. Endowed with unique textural and surface chemistry, aMIL‐88B(Fe2Zn) exhibits superior catalytic activity in the degradation of refractory organic pollutants. The progress offers a feasible way to rational design of iron‐based hybrid MOF materials with tunable structures and enhance properties for various applications.

ZIF-8 based bifunctional coatings with anticorrosive and antibacterial properties: A new design strategy for more efficiency

An efficient and simple in-situ/mechanical two-step strategy has been discovered for the fabrication of nanocontainers based on zeolite imidazole framework-8 (ZIF-8) with corrosion inhibitors (benzotriazole, BTA). The nanocontainers were applied in anticorrosive coatings with anticorrosion and antibacterial bifunctions for aluminum alloys AA2024. The effects of ZIF-8 modified with the corrosion inhibitor via different methods (in-situ, mechanical, and two-step strategies) on its morphology, composition, structure, loading/release behavior were studied and discussed. Results showed that the amount of loaded BTA was positively correlated with the crystal size of the final ZIF-8, impacting sustained release. Compared with the conventional primary load (in-situ and mechanical loading way), the two-step loading method (in-situ followed by mechanical treatment) achieved a higher BTA loading without evident ZIF-8 morphology and structure changes. The two-step modified (2-BTA@ZIF-8) powders exhibited good corrosion inhibition and remarkable antibacterial properties against Escherichia coli and Staphylococcus aureus. Additionally, the 1-BTA@ZIF-8 (in-situ strategy), 1-BTA/ZIF-8 (mechanical strategy) and 2-BTA@ZIF-8 composites were dispersed in acrylic resin to prepare anticorrosive and antibacterial bifunctional coatings. Results showed that the 2-BTA@ZIF-8 incorporated acrylic coatings exhibited superior anticorrosion performance and antimicrobial activity compared to the unmodified coating due to the controlled release of BTA. Thus, elaborated strategy represents a feasible and effective way to construct high-performance anticorrosive and antimicrobial coatings with metal-organic framework materials.

Phase Engineering of Zirconium MOFs Enables Efficient Osmotic Energy Conversion: Structural Evolution Unveiled by Direct Imaging.

Creating structural defects in a controlled manner within metal-organic frameworks (MOFs) poses a significant challenge for synthesis, and concurrently, identifying the types and distributions of these defects is also a formidable task for characterization. In this study, we demonstrate that by employing 2-sulfonylterephthalic acid as the ligand for synthesizing Zr (or Hf)-based MOFs, a crystal phase transformation from the common fcu topology to the rare jmt topology can be easily facilitated using a straightforward mixed-solvent strategy. The jmt phase, characterized by an extensively open framework, can be considered a derivative of the fcu phase, generated through the introduction of missing-cluster defects. We have explicitly identified both MOF phases, their intermediate states, and the novel core-shell structures they form using ultralow-dose high-resolution transmission electron microscopy. In addition to facilitating phase engineering, the incorporation of sulfonic groups in MOFs imparts ionic selectivity, making them applicable for osmotic energy harvesting through mixed matrix membrane fabrication. The membrane containing the jmt-phase MOF exhibits an exceptionally high peak power density of 10.08 W m-2 under a 50-fold salinity gradient (NaCl: 0.5 M|0.01 M), which surpasses the threshold of 5 W m-2 for commercial applications and can be attributed to the combination of large pore size, extensive porosity, and abundant sulfonic groups in this novel MOF material.

Metal-organic framework (MOF) dispersion based fluids for solar-thermal energy conversion

This paper discusses the potential use of metal–organic framework (MOF) dispersion based fluids for solar-to-thermal energy conversion (STEC). For this, the optical and thermal characteristics of MOF dispersion were investigated, with MOFs dispersed in ethylene glycol (EG). This study is focused on three different MOF dispersions, namely ZIF8/EG, CuBTC/EG, and FeBTC/EG, each with varying concentrations of MOF particles. The results showed that FeBTC/EG at a concentration of 0.3 wt% is the optimal fluid for STEC, exhibiting the highest absorption and STEC efficiency compared to the other two fluids. The study also highlights the trade-off between STEC efficiency and cost, as increasing the concentration of MOF particles decreases the specific absorption rate (SAR). Additionally, the paper evaluates the dispersion stability of FeBTC/EG over time, which is critical for practical STEC applications. The novelty of the paper lies in the use of MOF dispersion based fluids for STEC application, which has not been extensively studied before. This study provides valuable insights into the potential use of MOF/EG for STEC and highlights the importance of optimizing the concentration of MOF particles for efficient and cost-effective performance. This study also introduces the novel application of MOF dispersion based fluids for enhanced STEC performance, showcasing FeBTC/EG as a standout for its high efficiency and stability. It marks a significant stride in utilizing MOF materials for sustainable energy, emphasizing practical considerations of dispersion stability and cost-effectiveness in STEC systems.

Spacial regulation of precise aperture in metal–organic frameworks towards ultrahigh-selective mixed matrix membranes for low-energy-consumption C3H6/C3H8 separation

Membrane technology based on metal–organic framework (MOF) with molecular sieving properties is a promising alternative to energy-intensive conventional distillation for C3H6/C3H8 separation. However, precisely regulating the aperture of MOF materials for industrial separation processes with low energy consumption remains a significant challenge. Herein, we introduce a post-synthetic defect exchange, using ortho-trifluoromethylbenzoic acid (o-TBA) in defective UiO-66, resulting in a mixed matrix membrane (MMM) with a C3H6/C3H8 ideal selectivity of ∼ 104 and C3H6 permeability of ∼ 293 Barrer, and exhibiting a C3H6/C3H8 selectivity ∼ 36 with C3H6 permeability of ∼ 188 Barrer for a C3H6/C3H8 (50:50) mixture. Computational simulations confirm impact of o-TBA-UiO on reducing pore sizes and providing moderate propylene affinity. Static adsorption and solution-diffusion experimental results show that the o-TBA-UiO/6FDA-DAM membrane provides fast C3H6 diffusion rates but retards C3H8 diffusion, leading to ultrahigh C3H6/C3H8 selectivity. A large-area membrane of 2400 cm2 was prepared to promote practical applications, mainly because of the considerably enhanced affinity between o-TBA-UiO and 6FDA-DAM. At a feed pressure of 1 bar, the 1812-type membrane module exhibited a modest decline in single gas separation performance with a C3H6 permeability of ∼ 175 Barrer and a C3H6/C3H8 ideal selectivity of ∼ 96. Finally, a potential two-stage membrane process with low energy consumption was designed. This study provides a robust design for MOF-based MMMs with molecular sieving for energy-efficient gas separation.

Polyaniline modified bimetallic hydroxide/ZIF composites as electrode materials for supercapacitors with high capacity and high stability

Metal-organic framework materials (MOFs) are widely used in electrochemical energy storage due to their abundant active sites and high redox activity. Especially in the field of supercapacitors, the porous structure of MOFs makes them the most promising candidates for composite electrode materials due to their vast specific surface area. However, the poor chemical stability of MOFs in alkaline electrolytes limits their application. Constructing and improving the stability of metal-organic backbone materials through rational structural design is the key to enhancing the electrochemical performance of capacitors. In this paper, the stability of ZIF-67 was enhanced by the complexing with bimetallic hydroxide (CoMn-LDH), and the conductivity is further enhanced by the mixing of polyaniline (PANI) to form a ``network structure'' morphology. As a result, the composite electrode material has a specific capacity of 1048 F g−1 at 1 A g−1 with a good cycle life (80.5 % capacity retention for 5000 cycles). The specific capacity of the CoMn-LDH/ZIF-67/PANI//AC asymmetric supercapacitor (ASC) was 164 F g−1 at 1 A g−1 in the voltage range of 0–1.5 V. The maximum energy density of the ASC was 51.25 Wh kg−1 at a power density of 2250 W kg−1. In addition, excellent cycling stability (71.2 % capacitance retention after 5000 cycles) was delivered.

Microwave hydrothermal in situ synthesis of highly dispersed metal-organic framework@SiC as a promising structured catalyst

Metal-organic framework (MOF) materials with loaded catalysts have recently garnered substantial interest in the catalysis field. However, the catalytic performance of MOF catalysts is hindered by particle aggregation. This study introduces a microwave-assisted anchoring strategy to improve the dispersion of UIO-66-NH2 on SiC surfaces. The dispersion can be effectively controlled by varying the SiC carrier content. Scanning electron microscopy and transmission electron microscopy analyses show that as the SiC content increases from 2% to 10%, MOFs exhibit a more dispersed distribution on the surface. This is exemplified in the esterification reaction between acetic acid and cyclohexene, where a higher MOF dispersion leads to a conversion rate boost from 70% to 75%. Numerical simulations reveal that microwave's selective heating property plays a crucial role in achieving this enhanced dispersion. This work contributes a systematic approach to enhance MOF dispersion and advances the development of structured catalysts based on MOFs.