Metal–organic frameworks and their catalytic applications

Metal-organic frameworks (MOFs), as a novel categories of porous and well crystalline materials, were gained significant interest in the current years. These materials offer practical implementations in different sectors, like hydrogen and carbon dioxide storage, catalysis and separation due to their superior porosity, great surface area and versatile framework. The current review outlines the existing state of the art in using MOFs as catalysts in various organic transformation processes and photocatalysis depending on the site form, with particular confirmation on the most recent techniques for increasing the active centers and modifying their performance, by deposition of metallic nanoparticles on its surface or within the pores. In addition, the substantial progress made in the production of various composites containing MOF with particular focus on preparation and catalytic applications was provided.     

Metal–organic frameworks in diagnostics,therapeutics, and other biomedical applications

Metal–organic frameworks (MOFs) are emerging porous coordination polymers constructed by metal ions and organic linkers that have attracted numerous interests in recent years. The large surface area, high porosity, tunable size, and versatile functionality make them promising materials for cargo delivery (i.e., drugs, mRNA, dyes) and sensing (i.e., nucleic acids, small molecules, ions). In addition, the metal ions released from MOFs offer antibacterial and antifungal utility. This review presents a snapshot of current MOF-related research, highlighting the synthesis approaches, and the various bioapplications of MOFs in terms of biosensing platforms, drug delivery, and antimicrobial agents, exposing potential for future research in the MOF field.     

Metal/covalent organic frameworks for aqueous rechargeable zinc-ion batteries

Lithium-ion batteries(LIBs) have become one of the most successful energy storage systems due to their high operating voltage,high energy density, and long cycle life. However, with the widespread use of LIBs in recent decades, lithium resources are at risk of being exhausted. Therefore, it is necessary to find a substitute for LIBs to meet the needs of future large-scale energy storage systems. Because of their competitiveness, low cost, and high safety, aqueous rechargeable zinc-ion batteries(...     

Luminescent nanoscale metal–organic frameworks for chemical sensing

Metal–organic frameworks(MOFs) are a fascinating class of crystalline materials constructed from selfassembly of metal cations/clusters and organic ligands. Both metal and organic components can be used to generate luminescence, and can further interact via antenna effect to increase the quantum yield,providing a versatile platform for chemical sensing based on luminescence emission. Moreover, MOFs can be miniaturized to nanometer scale to form nano-MOF(NMOF) materials, which exhibit many advantages over conventional bulk MOFs in terms of the facile tailorability of compositions, sizes and morphologies, the high dispersity in a wide variety of medium, and the intrinsic biocompatibility. This review will detail the development of NMOF materials as chemical sensors, including the synthetic methodologies for designing NMOF sensory materials, their luminescent properties and potential sensing applications.     

Extended investigation of LiOH–LiBr binary system for high-temperature thermal energy storage applications

Journal of Thermal Analysis and Calorimetry - LiOH–LiBr binary system is thoroughly investigated by means of DSC and XRD experimental analysis. Observed discrepancies compared to previous...     

Advanced metal–organic frameworks for aqueous sodium-ion rechargeable batteries

Inexpensive and abundant sodium resources make energy storage systems using sodium chemistry promising replacements for typical lithium-ion rechargeable batteries(LIBs).Fortuitously,aqueous sodium-ion rechargeable batteries(ASIBs),which operate in aqueous electrolytes,are cheaper,safer,and more ionically conductive than batteries that operate in conventional organic electrolytes;furthermore,they are suitable for grid-scale energy storage applications.As electrode materials for storing Na~+ ions in ASIBs,a variety of multifunctional metal-organic frameworks(MOFs) have demonstrated great potential in terms of having porous 3 D crystal structures,compatibility with aqueous solutions,long cycle lives(≥1000 cycles),and ease of synthesis.The present review describes MOF-derived technologies for the successful application of MOFs to ASIBs and suggests future challenges in this area of research based on the current understanding.     

Progresses on electrospun metal–organic frameworks nanofibers and their wastewater treatment applications

Metal–organic frameworks (MOFs) have been proven to be outstanding adsorbent materials which possess excellent pollutant removal performances in wastewater treatment. However, MOFs consumption, loss, or blockage in reactor pipelines as well as the long and complicated recycling process severely limit their practical applications. Therefore, construction of novel MOFs composites with extremely high ease-of-use property has become a research hotspot, such as two-dimensional (2D) MOFs fibrous membranes. In this review, the exploitation of MOFs nanofibrous membranes via electrospinning and their applications in wastewater treatment are summarized. The MOFs nanofibers (NFs) architectures are established systematically by five routes: (1) direct electrospinning of MOFs-polymer; (2) induced growth of MOFs on electrospun NFs containing seeds; (3) growth of MOFs on electrospun organic NFs’ (4) growth of MOFs on electrospun inorganic NFs; and (5) simultaneous electrospinning and electrospraying. Furthermore, the applications of different types of MOFs nanofibrous membranes and their derivatives in water treatment and purification are discussed, including oil-water separation, the removal of heavy metal ions, organic dyes, personal care products, non-steroidal anti-inflammatory drugs (NSAIDs) and so on. The adsorption properties and mechanisms of electrospun MOFs nanofibrous membranes towards various environmental pollutants are discussed. Finally, the challenges of electrospun MOFs NFs, the limitations of their applications, and future development trends are prospected.     

Hybrid organic–inorganic materials: from child’s play to energy applications

The field of hybrids has boomed since its initial conception with silicones as structural materials to the wealth of different types of hybrid materials studied nowadays as functional materials. Hybrids based on conducting polymers and a great variety of inorganic species constitute a growing area of this field. We present a brief review of the intersection between conducting polymer hybrids and electrochemical applications to energy storage and conversion. But beyond examples of hybrids active in batteries, supercapacitors, solar or fuel cells, we have tried to convey the standing challenges concerning the design of chemically (and electrochemically) complex hybrid systems with components and building blocks ranging from extended oxides or nanoparticles to carbon or oxide nanotubes, to clusters and to molecules and the opportunities arising from their integration with conducting polymers.     

Ionic liquid–solid interface and applications in lubrication and energy storage

Room-temperature ionic liquids (ILs) exhibit many attractive properties in proximity to solid surfaces. Primarily, they form well-defined interfacial layers that are tunable — electrically and thermally — as well as being stable — mechanically, electrically, and thermally — over a wide range. Recent investigations have aimed at understanding the molecular structuring of ILs at their interface with solids and in confinement, while in tandem, ILs are used as next-generation lubricants and energy storage materials. The result is a large volume of work that has appeared over the last decade. In this review, the recent literature is presented and future research directions are discussed.     

Metal–organic framework-based mixed-matrix membranes for gas separation: An overview

Mixed-matrix membranes (MMMs) have been studied widely in the field of gas separation due to their potential to overcome performance barriers found in traditional polymeric membranes. Most polymeric membranes exhibit a trade-off between permeation and selectivity, which has limited their development in many challenging separation applications. One solution to this issue utilizes the introduction of fillers into the polymer matrix to produce MMMs. Out of the many different fillers, metal–organic frameworks stand out as a promising candidate due to their highly tunable structure, molecular sieving effect, and superior compatibility with the polymer matrix. This review will provide an in-depth look into the basic mechanisms of MMMs for gas separation and different approaches to model the permeation of gases through the membrane. In addition, challenges facing the field and recent research trends for MMMs will be discussed as well as their many applications for different gas separations. Finally, some insight on the future direction for MMMs will be covered, focusing on many intriguing opportunities and challenges that must be further explored to advance this technology.     

Recent advances in starch–clay nanocomposites

Biological nanocomposites are a valuable addition to the existing nanocomposite materials and eventually can substitute petroleum-based composite materials in numerous applications due to their inherent advantages such as biodegradability, eco-friendliness, low cost, and easy availability to name a few. Recently, polymer–clay nanocomposites have achieved much more attention due to their enhanced properties such as size dispersion and significant enhancement in physicochemical and mechanical properties in comparison to the pure polymer systems. Among various biopolymers, starch is one of the most abundant natural polymers on the earth and is highly valuable due to its chemical and physical properties. Starch polymer has highly increased potential as an alternative to petroleum-based materials. However, starch cannot be used alone and starch–clay nanocomposite has emerged as a new potential green sustainable material. This article focuses on recent progress in starch-based nanocomposites with particular emphasis on starch–clay nanocomposite preparation, properties, and applications.     

The application of Bimetallic metal–organic frameworks for antibiotics adsorption

Fe/Zr-base metal–organic frameworks(Fe/Zr-MOFs) were prepared using a solvothermal method from 1,3,5-phthalic acid (H₃BTC, 98 %) as the organic chain and ferrous heptahydrate (FeSO₄·7H₂O) and zirconium acetate Zr(CH₃COO)₄] as the metal ions. The resulting material was used to remove Doxycycline hydrochloride (DC). The experimental results showed that when the concentration of DC was 10 ppm and the mass of Zr/Fe-MOFs was 100 mg, the maximum removal rate after 5 h was 87.5 %. The results showed that the correlation coefficients (R²) of the pseudo-second-order kinetics model and Freundlich isotherm model of Zr/Fe-MOFs adsorption of DC were greater than 0.99, indicating good consistency. The results showed that the adsorption process of DC by Zr/Fe-MOFs was endothermic and spontaneous. Fe/Zr-MOFs had a high adsorption capacity for DC removal and good application prospects.     

Adsorption-based characterization of hierarchical metal–organic frameworks

Nitrogen adsorption at 77 K on metal–organic framework (MOF) is investigated by means of molecular simulations. We consider both regular Cu–BTC crystal and a MOF-based hierarchical porous solid consisting of a mesopore carved out of a Cu–BTC crystal. The t-plot method is applied to these solids by using a non-porous Cu–BTC surface as the reference sample. The values of the mesoporous and external surface areas are determined from the t-plot, and the validity of the method for this type of hierarchical solid is discussed.     

Recent advances on flexible electrodes for Na-ion batteries and Li–S batteries

Flexible energy storage devices are essential for emerging flexible electronics. The existing state-of-the-art Li-ion batteries are slowly reaching their limitation in terms of cost and energy density. Hence, flexible Na-ion batteries(SIBs) with abundance Na resources and Li–S batteries with high energy density become the alternative for the Li-ion batteries in future. This review summarizes the recent advances in the development of flexible electrode materials for SIBs with metallic matrix and carbonaceous matrix such as carbon nano-tubes, carbon nano-fiber, graphene, carbon cloth, carbon fiber cloth, and cotton textiles.Then, the potential prototype flexible full SIBs are discussed. Further, the recent progress in the development of flexible electrode materials for Li–S batteries based on carbon nano-fiber, carbon nano-tubes,graphene, and cotton textiles is reviewed. Moreover, the design strategies of suitable interlayer, separator,electrolyte, and electrodes to prevent the dissolution and shuttle effect of polysulfides in flexible Li–S batteries are provided. Finally some prospective investigation trends towards future research of flexible SIBs and Li–S batteries are also proposed and discussed. The scientific and engineering knowledge gained on flexible SIBs and Li–S batteries provides conceivable development for practical application in near future.     

Metal–organic frameworks as efficient materials for drug delivery: Synthesis,characterization, antioxidant,anticancer, antibacterial and molecular docking investigation

Metal–organic framework (MOF) nano particles are a class of promising porous nano materials for biomedical applications. Owing to its high loading potential and pH-sensitive degradation, most promising of the MOFs is the zeolitic imidazolate crystal framework (ZIF-8), a progressive useful material for small molecule distribution. Doxorubicin (DOX), designated as a classical drug, was jobwise entrapped in ZIF-8 nano particles. ZIF-8 nano particles, as a novel carrier, were used to monitor the release of the anticancer drug DOX and prevent it from dissipating before reaching its goal. ZIF-8 nano particles with encapsulated DOX (DOX@ZIF-8) can be synthesized in a single pot by incorporation of DOX into the reaction mixture. MOFs and the designed drug delivery (DOX@ZIF-8) system were characterized by Fourier transfer infrared, scanning electron microscopy, N₂ sorption isotherm and X-ray diffraction. The impact of MOFs and the engineered drug delivery system on the viability of human breast and liver cancer cell lines was evaluated. The loaded drug was released at pH 5 faster than at pH 7.4. The nano particles of ZIF-8 showed low cytotoxicity, while DOX@ZIF-8 showed high cytotoxicity to HepG-2 and MCF-7 cells compared with free DOX at the equivalent concentration of DOX of >12.5 μg/ml. These findings indicate that DOX@ZIF-8 nano particles are a promising method for the delivery of cancer cells to drugs. Furthermore, ZIF-8, DOX and encapsulated DOX@ZIF-8 compounds were screened for their potential antibacterial activities against pathogenic bacteria compared with standard antibiotics by the agar well diffusion technique. The results demonstrate that the DOX@ZIF-8 exhibits a strong inhibition zone against Gram-negative strains (Escherichia coli) in comparison with the reference drug gentamycin. The docking active site interactions were evaluated to predict the binding between DOX with the receptor of breast cancer 3hb5-oxidoreductase and liver cancer 2h80-lipid binding protein for anticancer activity.