Metal-organic Frameworks Structures Research Articles

Rational Design and Reticulation of Infinite qbe Rod Secondary Building Units into Metal–Organic Frameworks through a Global Desymmetrization Approach for Inverse C3H8/C3H6 Separation

AbstractThe development of reticular chemistry has enabled the construction of a large array of metal–organic frameworks (MOFs) with diverse net topologies and functions. However, dominating this class of materials are those built from discrete/finite secondary building units (SBUs), yet the designed synthesis of frameworks involving infinite rod‐shaped SBUs remain underdeveloped. Here, by virtue of a global linker desymmetrization approach, we successfully targeted a novel Cu‐MOF (Cu‐ASY) incorporating infinite Cu‐carboxylate rod SBUs with its structure determined by micro electron diffraction (MicroED) crystallography. Interestingly, the rod SBU can be simplified as a unique cylindric sphere packing qbe tubule made of [43.62] tiles, which further connect the tritopic linkers to give a newly discovered 3,5‐connected gfc net. Cu‐ASY is a permanent ultramicroporous material featuring 1D channels with highly inert surfaces and shows a preferential adsorption of propane (C3H8) over propene (C3H6). The efficiency of C3H8 selective Cu‐ASY is validated by multicycle breakthrough experiments, giving C3H6 productivity of 2.2 L/kg. Density functional theory (DFT) calculations reveal that C3H8 molecules form multiple C−H⋅⋅⋅π and atypical C−H⋅⋅⋅ H−C van der Waals interactions with the inner nonpolar surfaces. This work therefore highlights the linker desymmetrization as an encouraging and intriguing strategy for achieving unique MOF structures and properties.

Rational Design and Reticulation of Infinite qbe Rod Secondary Building Units into Metal-Organic Frameworks through a Global Desymmetrization Approach for Inverse C3 H8 /C3 H6 Separation.

The development of reticular chemistry has enabled the construction of a large array of metal-organic frameworks (MOFs) with diverse net topologies and functions. However, dominating this class of materials are those built from discrete/finite secondary building units (SBUs), yet the designed synthesis of frameworks involving infinite rod-shaped SBUs remain underdeveloped. Here, by virtue of a global linker desymmetrization approach, we successfully targeted a novel Cu-MOF (Cu-ASY) incorporating infinite Cu-carboxylate rod SBUs with its structure determined by micro electron diffraction (MicroED) crystallography. Interestingly, the rod SBU can be simplified as a unique cylindric sphere packing qbe tubule made of [43 .62 ] tiles, which further connect the tritopic linkers to give a newly discovered 3,5-connected gfc net. Cu-ASY is a permanent ultramicroporous material featuring 1D channels with highly inert surfaces and shows a preferential adsorption of propane (C3 H8 ) over propene (C3 H6 ). The efficiency of C3 H8 selective Cu-ASY is validated by multicycle breakthrough experiments, giving C3 H6 productivity of 2.2 L/kg. Density functional theory (DFT) calculations reveal that C3 H8 molecules form multiple C-H⋅⋅⋅π and atypical C-H⋅⋅⋅ H-C van der Waals interactions with the inner nonpolar surfaces. This work therefore highlights the linker desymmetrization as an encouraging and intriguing strategy for achieving unique MOF structures and properties.

Multi-Enzyme Activity of MIL-101 (Fe)-Derived Cascade Nano-Enzymes for Antitumor and Antimicrobial Therapy.

The clinical application of oncology therapy is hampered by high glutathione concentrations, hypoxia, and inefficient activation of cell death mechanisms in cancer cells. In this study, Fe and Mo bimetallic sulfide nanomaterial (FeS2@MoS2) based on metal-organic framework structure is rationally prepared with peroxidase (POD)-, catalase (CAT)-, superoxide dismutase (SOD)-like activities and glutathione depletion ability, which can confer versatility for treating tumors and mending wounds. In the lesion area, FeS2@MoS2 with SOD-like activity can facilitate the transformation of superoxide anions (O2 -) to hydrogen peroxide (H2O2), and then the resulting H2O2 serves as a substrate for the Fenton reaction with FMS to produce highly toxic hydroxyl radicals (∙OH). Simultaneously, FeS2@MoS2 has an ability to deplete glutathione (GSH) and catalyze the decomposition of nicotinamide adenine dinucleotide phosphate (NADPH) to curb the regeneration of GSH from the source. Thus it can realize effective tumor elimination through synergistic apoptosis-ferroptosis strategy. Based on the alteration of the H2O2 system, free radical production, glutathione depletion and the alleviation of hypoxia in the tumor microenvironment, FeS2@MoS2 NPS can not only significantly inhibit tumors in vivo and in vitro, but also inhibit multidrug-resistant bacteria and hasten wound healing. It may open the door to the development of cascade nanoplatforms for effective tumor treatment and overcoming wound infection.

H‐Bond Modulation Mechanism for Moisture‐driven Bacteriostat Evolved from Phytochemical Formulation

AbstractThe development of environment‐friendly bacteriostats in humid atmosphere is designated as a crucial step pointing to sustainable antibiotic‐free alterative. Thanks to the excellent biosafety and intrinsic bacteriostatic attributes, bioactive phytochemical formulations become a fascinating substitute for traditional antibiotics; yet, it remains a challenge to deliver them toward moisture‐activated bacteriostatic application due to the unclear release mechanism and bacteriostatic behavior. Benefitting from “green” metal–organic frameworks (MOFs) evolved from natural γ‐cyclodextrin (γ‐CD) and potassium ion (K+), an intelligent moisture‐activated phytochemical formulation is developed, which is featured by grafting bacteriostatic vanillin (a specific phytochemical extracted from Rutaceae vanilla bean) into microporous structure of MOFs via ligand implantation mechanism. According to the molecular simulation docking, the dominant pattern of host–guest structure is characteristic for H‐bond with a length of 1.9 Å, beneficial for the sterling adsorption capacity. Nevertheless, under moisture exposure, the intermolecular H‐bond is disrupted for vanillin release to destroy bacterial membrane structure, accelerate protein decomposition, and especially inhibit virulence gene transcription of cfa gene in Escherichia coli and sea gene in Staphylococcus aureus, directing to upgrade the insights into the bacteriostatic potency of phytochemicals in high‐humidity circumstance.

Metal-Organic Framework Based on Pyrazinoquinoxaline Tetracarboxylic Acid for Fluorescence Sensing for Nitro Explosives.

The rapid and selective detection of nitro explosives has become one of the current urgent environmental and safety issues. Fluorescent metal-organic frameworks (MOFs) provide strong support for the development of photoactive materials with excellent sensing performances. In this work, Zn2+ and pyrazinoquinoxaline tetracarboxylic acid with high nitrogen content were selected to construct a MOF structure termed Zn-MOF, which had excellent optical properties. The fluorescence sensing performance of Zn-MOF for nitro explosives was also investigated. The structural advantages of Zn-MOF, such as its porous structure, abundant host-guest interaction sites, and stable framework, ensure the prerequisites for various applications. Zn-MOF is not only capable of responding to a wide range of substrates, such as Fe3+, Cr2O72-, and MnO4-, to achieve fluorescence quenching detection but also able to achieve sensitive fluorescence sensing behavior for nitro explosives. In particular, for trinitrotoluene, the Ksv value can reach 8.72 × 103 M-1. The results show that the introduction of pyrazinoquinoxaline groups into MOFs can be an effective strategy for the preparation of highly efficient fluorescent sensing materials for nitro explosives.

Development of packaging films based on UiO-66 MOF loaded melatonin with antioxidation functions for spinach preservation

Spinach tends to deteriorate after harvest due to physiological metabolic activities. As a natural, pollution-free, and environmentally friendly preservative, melatonin (MT) can effectively maintain the quality of fruits and vegetables after harvest and delay senescence. To enhance the preservation effect of MT, this study developed antioxidant films using MT-loaded UiO-66 metal–organic framework (MOF) nanoparticles. This approach effectively extends the shelf life of spinach while preserving its quality. The underlying mechanism involves leveraging the microporous structure and stability of UiO-66 MOF. Experimental results obtained from the packaging films demonstrated significant improvements in both mechanical strength and antioxidant properties when UiO-66 was loaded with MT at a concentration of 0.20 mg/mL and combined with sodium alginate. Freshness preservation experiments also indicated the effective preservation effect of these films on spinach. In conclusion, the results of this study suggest that MT-loaded UiO-66 MOF is a promising active packaging material for spinach preservation.

Ratiometric fluorescence sensor based on europium-organic frameworks for selective and quantitative detection of cerium ions

BackgroundDue to the unavoidable use of cerium in daily life, the accumulation of cerium in the environment increases health risks for humans. Therefore, it is crucial to develop a chemical sensing technology for the rapid, sensitive, and selective detection of cerium ions. ResultsIn this research work, a novel two-dimensional chain structure of a europium-based metal organic framework (Eu-MOF) [Eu2(tcpa)(Htcpa)2] was synthesized by using 3,4,5,6-tetrachloro-1,2-benzenedicarboxylic acid (H2TCPA) as the ligand and europium nitrate as the metal source. The results of powder X-ray diffraction and thermogravimetric analysis show that the synthesized Eu-MOF has excellent chemical and thermal stability. When the Eu-MOF suspension was excited by ultraviolet light at 292 nm, four fluorescence emissions were observed at 420, 595, 620 and 705 nm. It was particularly interesting that when cerium ions (Ce3+/Ce4+) were added to the Eu-MOF suspension, the fluorescence intensity at 420 nm was enhanced, while the fluorescence at 620 nm was quenched. On this basis, a ratiometric fluorescent sensor for detecting cerium ions was constructed, which has a good linear relationship in the range of 0.05–15 μM and a detection limit of 16 nM. The plausible mechanism of the change in the fluorescence characteristics of Eu-MOF caused by cerium ions was discussed in detail. Through the study of fluorescence lifetime and ultraviolet absorption, it was proven that the mechanism of Ce3+-quenching Eu-MOF fluorescence is the inner filter effect. Photoinduced electron transfer and internal filtering effects lead to fluorescence quenching at 620 nm, while redox reactions lead to fluorescence enhancement of the ligand at 420 nm. SignificanceThe proposed ratiometric fluorescence sensor was successfully employed for the detection of cerium ions in real water samples, confirming that it can be used as an alternative method for the detection of Ce3+ and Ce4+ in environmental samples.

BIMMOF-derived ZnS/Co9S8 heterojunctions decorated hollow carbon nanospheres as advanced anode materials for lithium-ion batteries

Metal-organic frameworks (MOFs) offer significant advantages for constructing bimetallic sulfides as anode materials for lithium-ion batteries. However, the crystal structure of pure MOFs tends to collapse during ion insertion and detachment, resulting in somewhat limited electrochemical performance. Here, the crystal size of the bimetallic organic framework (BIMMOF) is reduced by in situ growth on hollow carbon spheres (HCS) by the solvothermal method. As a result, the well-dispersed BIMMOF-derived ZnS/Co9S8 heterojunction anode material was obtained with hollow carbon spheres as support. Due to the unique structure of ZnS/Co9S8@N-HCS with ultrafine size and the synergistic effect of Zn2+ and Co2+, this anode material has excellent electrochemical performance. Especially, it exhibits a capacity of 1595 mAh g−1 after 100 cycles at 100 mA g−1 and maintains a capacity of 1109 mAh g−1 after 1800 cycles at 2500 mA g−1. The remarkable lithium storage properties demonstrated by the ZnS/Co9S8 heterostructure provide inspiration for the wide adoption of this structural design strategy to improve the electrochemical performance of bimetallic sulfide anodes.

Highly effective quantum sieving of hydrogen isotopes on flexible metal-organic frameworks with mobile ligands

The separation of hydrogen isotopes is crucial in nuclear energy and biomedicine, but current techniques have limited separation coefficients. Utilizing flexible metal-organic frameworks (MOFs) with quantum sieving capabilities offers a promising solution. However, achieving high hydrogen isotope adsorption capacity while maintaining a high separation factor remains a challenge. This study presents a novel approach for the quantum sieving of hydrogen isotopes using MOFs with mobile ligands. The stable crystal structure of the microporous MOFs enables large hydrogen isotope adsorption capacity. The presence of mobile ligands acts as the gate in the dynamic adsorption and separation process, enhancing the performance of hydrogen isotope separation. The smaller quantum radius and larger molecular weight of deuterium facilitate its easier entry into the micropores, resulting in a maximum selectivity for D2 over H2 of 36.7 and a D2 uptake of 17.3 mmol g−1. Furthermore, the kinetic quantum sieving of hydrogen isotopes necessitates MOFs with mobile ligands that maintain their flexibility from 20 K to 70 K, as demonstrated by ultralow-frequency Raman spectra.

Heterostructured Bimetallic MOF-on-MOF Architectures for Efficient Oxygen Evolution Reaction.

Electron modulation presents a captivating approach to fabricate efficient electrocatalysts for the oxygen evolution reaction (OER), yet it remains a challenging undertaking. In this study, an effective strategy is proposed to regulate the electronic structure of metal-organic frameworks (MOFs) by the construction of MOF-on-MOF heterogeneous architectures. As a representative heterogeneous architectures, MOF-74 on MOF-274 hybrids are in situ prepared on 3D metal substrates (NiFe alloy foam (NFF)) via a two-step self-assembly method, resulting in MOF-(74 + 274)@NFF. Through a combination of spectroscopic and theory calculation, the successful modulation of the electronic property of MOF-(74 + 274)@NFF is unveiled. This modulation arises from the phase conjugation of the two MOFs and the synergistic effect of the multimetallic centers (Ni and Fe). Consequently, MOF-(74 + 274)@NFF exhibits excellent OER activity, displaying ultralow overpotentials of 198 and 223mV at a current density of 10mA cm-2 in the 1.0 and 0.1M KOH solutions, respectively. This work paves the way for manipulating the electronic structure of electrocatalysts to enhance their catalytic activity.

Utilizing a defective MgO layer for engineering multifunctional Co-MOF hybrid materials with tailored leaf-like and polyhedral structures for optimal electrochemical and photocatalytic activities

The hybridization of metal-organic framework (MOF) with inorganic layers would lead to the discovery of novel hybrid materials that can provide a compelling strategy for enhancing its photocatalytic and electrochemical response. In the present study, a highly efficient multifunctional hybrid material was developed by exploiting the defective layer formed on AZ31 Mg alloy through plasma electrolytic oxidation (PEO) as a nucleation and growth site for Co-MOF. The concentrations of the organic linker 2-Methylimidazole (2,MIm) and cobalt nitrate as a source of Co2+ ions were varied to control the growth of the obtained Co-MOF. Lower concentrations of the 2, MIm ligand favored the formation of leaf-like MOF structures through an anisotropic, two-dimensional growth, while higher concentrations led to rapid, isotropic nucleation and the creation of polyhedral Co-MOF structures. The sample characterized by polyhedral Co-MOF structures exhibited superior electrochemical stability, with the lowest corrosion current density (3.11 ​× ​10−9 A/cm2) and the highest top layer resistance (2.34 ​× ​106 ​Ω ​cm2), and demonstrated outstanding photocatalytic efficiency, achieving a remarkable 99.98 ​% degradation of methylene blue, an organic pollutant, in model wastewater. To assess the active adsorption sites of the Co-MOF, density functional theory (DFT) was utilized. This study explores the changes in morphologies of the coatings of Co-MOF with the change of solution concentration to form coatings with enhanced properties on the metallic substrate, which could establish the groundwork for the development of next-generation multifunctional frameworks with diverse applications.

Applications and Outlooks for MOFs in Food Engineering

Food detection and food packaging play critical roles in the realm of food engineering in maintaining food safety and quality. Because of the specific large surface area (SSA) and customizable topologies, metal-organic frameworks (MOFs) have become recognized as promising materials with distinctive features. Examples of MOFs employed as photochemical and electrochemical sensors for food detection are provided in this research. These MOF-based sensors have great selectivity and sensitivity, making it possible to quickly and accurately identify pollutants or signs of food rotting in samples. Additionally, the use of MOFs in food packaging has advantages including a longer shelf life and antibacterial qualities. Food is protected from outside influences by being enclosed within MOF structures, which delays deterioration and rotting. Additionally, MOFs with antibacterial qualities can successfully stop the growth of microbes, ensuring the safety of food. MOFs have the potential to be used in new application areas, such as the controlled release of dietary supplements and flavor enhancers, in addition to food detection and packaging. To guarantee the stability and effectiveness of MOFs in various applications, additional study is necessary. The relevance of food detection and packaging in food engineering is highlighted in this paper's conclusion, which also explores the potential of MOFs as adaptable tools in both fields. The examples shown show how important MOFs are as sensors and packaging materials, but further study is needed to fully utilize their potential and address any issues that might arise.

Effect of Guest Solvents on the Ionic Conductivity and Electrochemical Performance of Metal-Organic Framework-Based Magnesium Semi-Solid Electrolytes.

Developing suitable electrolytes is crucial for the advancement of rechargeable magnesium batteries. Recently, metal-organic frameworks (MOFs) have shown a great interest in the field of solid electrolytes for metal ion batteries. However, the ionic conductivity as well as the electrolyte stability in the presence of Mg electrodes are shown to be strongly dependent on the guest solvent used to solvate Mg salts in MOFsSEs. Our measurements showed that full evacuation of the MOF structure before semi-solid electrolytes (sSEs) preparation is crucial for achieving relatively low Mg overpotentials regardless of the ionic conductivity values. Moreover, the behavior of the anode/MOFsSEs interfaces (MOF: α-Mg3 [HCOO]6 ; Mg salt : MgCl2 -Mg[TFSI]2 (1 : 1 wt %); guest solvent: acetone, DMF, DEG, DME and tetraglyme) was investigated by EIS, CV and galvanostatic measurements. The current comparative study of the electrochemical deposition processes of magnesium from MOFsSEs revealed that magnesium deposition/dissolution reactions vary depending on the MOF structure, the guest anion species as well as the nature of the guest solvents.

Orange peel-derived carbon dots/Cu-MOF nanohybrid for fluorescence determination of l-ascorbic acid and Fe3+

Recycling and reuse of biomass waste in synthesis of nanomaterials have recently received much attention as an effective solution for environmental protection and sustainable development. Herein, nitrogen-doped carbon dots (N-CDs) with blue emission were synthesized from the orange peels as a precursor through a simple hydrothermal method and then, modified with ethylenediamine tetraacetic acid (N-CD@EDTA). The N-CD@EDTA was embedded as a fluorophore in Cu-based metal-organic framework (MOF-199) structure (N-CD@EDTA/MOF-199) to construct fluorescence sensor toward l-ascorbic acid (L-AA) determination. The N-CD@EDTA/MOF-199 nanohybrid significantly and selectively turned on toward L-AA determination during the fluorimetric experiments. Under optimal conditions, the probe showed a suitable linear response in the concentration range of 10 nM–100 μM with a low limit of detection (LOD) of 8.6 nM and high sensitivity of 0.201 μM−1. The possible mechanism of recognition and adsorption, including the reduction of Cu 2+ nodes in the MOF-199 structure in the presence of L-AA and the release of trapped N-CD@EDTA into the solution, was explored. Moreover, the N-CD@EDTA/MOF-199/L-AA (100 μM) system was further applied as a fluorescent “on–off” sensor for Fe3+ determination with a LOD of 1.15 μM. The proposed probe was successfully used in orange juice and water samples to determine L-AA and Fe3+ with satisfactory recovery, which displays the promising capability of sensor in real samples. The recoveries obtained by suggested method are consistent with that obtained from high performance liquid chromatography (HPLC) and atomic absorption spectroscopy which confirm the favorable characteristic of the sensor for accurate determination of L-AA and Fe3+ in practical applications.

Bienzyme co-immobilized on Zr-Based MOF with hierarchical porous structure for visual detection of glucose

Metal-organic frameworks (MOFs) are considered as promising carriers for immobilized enzymes. Whereas, some interrelated and restrictive problems exist in the construction of MOFs immobilized enzymes with excellent catalytic performance, resulting in reduced catalytic activity of the enzymes. In this work, a novel hierarchical porous structure of Zr-based metal-organic frameworks (Zr-MOF, HPU) was accurately constructed for co-immobilizing horseradish peroxidase (HRP) and glucose oxidase (GOx). The prepared HPU carrier can enrich the substrate by using the abundant micropore structure around the mesopore, thus reducing the mass transfer resistance and making up for the loss of enzyme activity during enzyme immobilization. Notably, GOx-HRP@HPU demonstrated outstanding catalytic efficiency and excellent stability, as well as ideal reusability, maintaining nearly 95% initial activity at 60 ℃ after 1 h incubation and above 65% initial activity after 10 reuses. Both the immobilization process and interaction of substrates with co-immobilized bienzyme reactor were investigated by means of microcalorimetry, which demonstrated HPU was an excellent platform for co-immobilized HRP and GOx. Furthermore, GOx-HRP@HPU was used for the detection of glucose with excellent detection performance.

Synthesis and structure of anhydrous Zn2EDTA metal-organic framework

Metal-organic frameworks (MOFs) have gained significant attention in materials science due to their unique properties such as high surface area, porosity, and tunable electrochemical characteristics. Among various MOFs, Zn-EDTA compounds have shown potential for electrochemical applications. This paper presents the accident discovery and investigation of a new anhydrous Zn2(EDTA) MOF and its electrochemical performance as an electrode material for aqueous sodium-ion batteries. The study systematically explores the influence of pH and stoichiometric ratio on the formation of Zn2(EDTA) and Zn2(EDTA)(H2O) MOFs using X-ray diffraction analysis. The single-phase anhydrous Zn2(EDTA) compound is synthesized, offering advantages over the hydrated form regarding stability and electrochemical activity. Zn2(EDTA) structure is characterized, revealing a 3D network of channels suitable for interstitial ionic mobility. Thermogravimetric analysis (TGA) is used to study the thermal behavior of Zn2(EDTA), showing two weight loss steps attributed to water and carbon dioxide elimination during decomposition. Electrochemical measurements using cyclic voltammetry in alkaline and neutral electrolytes demonstrate the electrochemical activity of Zn2(EDTA) as an anode material for aqueous sodium-ion batteries. The results suggest that the electrochemical process in both electrolytes involves the reversible stripping/deposition of zinc ions. The anhydrous Zn2(EDTA) MOF exhibits higher peak current intensities and more positive potentials than the hydrated form. The study provides valuable insights for synthesizing and controlling Zn2(EDTA) MOF formation, opening the prospects for searching for new structures in considered-to-be-studied phase regions.

Microwave-assisted rapid controllable synthesis of hexagonal prismatic CoNi-MOF-74 and its derivative for efficient oxygen evolution reaction

Optimizing the composition and structure of metal-organic framework (MOF) materials has been proven effective in enhancing the performance of the oxygen evolution reaction (OER). However, rapid and controllable synthesis of MOF materials still faces challenges. In this work, we employed microwave assistance and surfactant soft templating to achieve rapidly synthesize CoNi-MOF-74 with controllable morphology. By incorporating 4% polyvinyl pyrrolidone (PVP), we successfully synthesized uniform hexagonal PVP4%-CoNi-MOF-74 within a remarkably short time of only 20 min. The PVP4%-CoNi-MOF-74 exhibited a mesoporous structure, displaying an impressive BET surface area of 1321.8 m2/g. PVP4%-CoNi-C alloy was obtained through a direct high-temperature treatment of PVP4%-CoNi-MOF-74 in an N2 environment. The PVP4%-CoNi-C alloy successfully preserved their initial morphology and pore structure, and exhibited excellent OER performance. At a current density of 10 mA/cm2 in a 1.0 M KOH solution, it demonstrated an overpotential of 310 mV, outperforming the commercial precious metal catalyst RuO2 (overpotential of 394 mV). Impressively, even after 3000 cycles, the overpotential of PVP4%-CoNi-C alloy only experienced a minimal positive shift of 0.02 V, showcasing its excellent stability. Through a combination of experimental findings and DFT calculations, it is believed that the superior OER performance of the PVP4%-CoNi-C alloy can be attributed to its morphological dependence induced by the hexagonal prism structure, its large specific surface area facilitating more active sites, as well as the enhanced coordination interactions and faster electron transfer capabilities provided by the unique CoNi active site module.

Ligand-engineered Ni-based metal–organic frameworks for electrochemical oxygen evolution reaction

Regulating morphology and crystal structure of metal–organic frameworks (MOFs), as well as fabricating bimetallic MOFs have been widely proposed to optimize the electronic structure of MOFs and thus enhance electrochemical oxygen evolution reaction (OER) activity. Distinguish from these conventional and complex strategies, this work mainly focuses on the convenient ligand-engineering strategy to optimize the electronic structure of Ni-MOFs. Specifically, the electron-rich ferrocene (Fc) unit is linked into the ligand of Ni-MIL-53-NH2 by the stable covalent bond on the basis of Schiff-base reaction. Noticeably, the resulting Ni-MIL-53-Fc exhibits significantly enhanced OER activity compared to parent Ni-MIL-53-NH2, achieving 6.6-times improvement of TOF value from 0.19 to 1.25 s−1 at the overpotential of 350 mV. Further characterizations confirm that the incorporation of Fc unit can enhance the charge transfer, which induces more electrons aggregated in the Ni active sites and thus improves the intrinsic activity of Ni sites toward OER activity. This ligand-engineering strategy can be extended to fabricate highly active and stable catalysts toward other electrocatalytic reactions.

Cobalt carbonate hydroxide-embedded in multi-layered holey nanoflower cross-linked with carbon nanotube for highly efficient supercapacitors with ultrahigh rate performance

In this work, bimetallic nickel-cobalt based metal organic framework (MOF) is in-situ grown on 2D laminar Co2(OH)2CO3 with multi-walled carbon nanotubes (MWCNTs) aid to form nanoflower-like hierarchical porous heterogeneous structure for advanced supercapacitor application. Benefitting from the low crystal surface energy of Co2(OH)2CO3, its intersection and connection with MOF generate convenient electron path and open channel for ionic transmission, and large contact area. The high aromaticity of MWCNTs slows down destruction for MOF structure from water molecule through providing hydrophobic environment, guaranteeing stable presence of the resulting composite in aqueous electrolyte. The synergistic effect of Ni/Co with high redox activity in bimetallic NiCo-MOF provides rapid and multiple redox reactions for enhanced capacitance. Taking full advantage of promising merits of individual components, the optimized NiCo MOF-Co2(OH)2CO3 nanosheet-MWCNT30 (NCM-NS-CNT30) composite under MWCNT dosage of 30 mg delivers greatly enhanced specific capacitance (1773 F g−1 at 1 A g−1) and obviously improved rate performance (96.5 % retention at 10 A g−1). Based on it, the fabricated hybrid supercapacitor (HSC) NCM-NS-CNT30//AC presents comparatively good energy density (30.625 Wh Kg−1), superior to most recently reported Ni, Co-based supercapacitors.

Metal-organic frameworks functionalized cellulosic fabrics as multifunctional smart textiles

Metal-organic frameworks (MOFs) have recently garnered significant attention in fabricating functional textiles due to their remarkable adsorption capacities and open metal sites. This study presents a rapid and straightforward method for the in-situ surface functionalization of cellulosic textiles with different MOF structures, including MOF-5, MOF-199, ZIF-8, and ZIF-67. The resulting fabrics exhibit substantially increased surface areas compared to the pristine fabric. A comprehensive comparative analysis of these multifunctional fabrics has been conducted, considering factors such as ease of growth, surface area, wash durability, malodor adsorption capacity, UV-blocking attributes, antimicrobial efficacy, and commercial viability. Our results demonstrate that all MOF-treated textiles effectively capture a variety of malodors, including isovaleric acid, nonenal, and indole, at concentrations up to 1000 ppm. Further, these textiles also show the high adsorption capacity of aniline, a model air pollutant, with levels ranging from 15.5 to 22.87 mg/g. Notably, all MOF-treated samples exhibit impressive antimicrobial performance, with nearly 99.9 % effectiveness against both E. coli and S. aureus. MOF-199@CMC and ZIF-67@CMC fabrics also display exceptional UPF (Ultraviolet Protection Factor) values, reaching 238 and 149, respectively. Considering variables such as solvents employed during synthesis, the visual aesthetics imparted by the finish, and the wash durability of the different MOF-functionalized fabrics, ZIF-8@CMC stands out as the superior choice, surpassing MOF-5@CMC, MOF-199@CMC, and ZIF-67@CMC fabrics. These MOF functionalized textiles can potentially be used as highly effective protective textiles.