The MIL-88A-Derived Fe3O4-Carbon Hierarchical Nanocomposites for Electrochemical Sensing

Zwitterionic MOF-embedded alginate beads with polydopamine surface functionalization for efficient doxycycline removal: Optimization and mechanistic study

The adsorptive removal of amphoteric antibiotics like doxycycline (DOX) is a difficult task because of the electrostatic repulsion between these amphoteric molecules and adsorbents. For this purpose, a zwitter adsorbent was fabricated by incorporating zwitter ZIF-67/MIL-88A binary MOF into the matrix of alginate (Alg); in addition, the surface of the beads was modified by polydopamine (PDA). The batch experiments implied the super-high adsorption efficacy of ZIF-67/MIL-88A@Alg@PDA toward DOX attained 384.61 ± 5.08 mg/g at a neutral pH medium, 25 °C, and using 0.02 g. The isotherm analysis implied the physisorption of DOX onto ZIF-67/MIL-88A@Alg@PDA, while the kinetic analysis denoted the chemisorption of DOX. The results of XPS, Zeta potential, and Lab experiments identified the types of physical and chemical interactions between ZIF-67/MIL-88A@Alg@PDA and DOX. The durability of the ZIF-67/MIL-88A@Alg@PDA beads was inspected by the recycling test, clarifying that the DOX adsorption aptitude declined by 12.22 mg/g. In addition, the measured leaching concentrations of cobalt and iron from the leaching test were 0.008 and 0.098 mg/L. The ionic strength of ZIF-67/MIL-88A@Alg@PDA, implying an enhancement in the DOX removal (%) from 83.51 to 93.50 % by raising the NaCl concentration from 0.2 to 1.0 mol/L. Therefore, our study could provide a simple procedure to overcome the electrostatic repulsion that retard the adsorption process of the amphoteric drugs onto charged adsorbents with positive or negative charges. Additionally, this procedure could also generate an electrostatic interaction between the zwitter adsorbents and the amphoteric drugs at specific pH media when they are in a zwitterionic nature.

Ir-Doped Core-Shell Hollow Heterogeneous Nanospindles for Electrocatalytic Oxygen Evolution Reaction

By utilizing Metal-organic framework (MOF) materials as a base, constructing electrocatalysts with heterogeneous structures offers advantages for catalyzing water splitting. In this study, a hollow heterogeneous nanocatalyst, Ir-MIL-88A@NiFe-LDHs, was prepared by growing a layered double hydroxides (LDHs) shell on MIL-88A substrate. The catalyst shows excellent oxygen evolution reaction (OER) performance in a 1.0 M KOH solution, requiring only 217 mV overpotential to achieve a current density of 10 mA cm-2 with a Tafel slope of 62.18 mV dec-1, indicating significant electrocatalytic performance and reaction kinetics characteristics. Furthermore, long-term OER testing also demonstrates the catalyst's outstanding stability. Emphasizing the interfacial interaction between MOF and LDHs, as well as the synergistic effect among Ni, Fe, and Ir elements, the study highlights how these factors collaboratively control the local electronic structure of the hollow Ir-MIL-88A@NiFe-LDHs, resulting in an efficient MOF-derived electrocatalyst.

Simple synthesis of peanut shell-like MoCoFe-HO@CoMo-LDH for efficient alkaline oxygen evolution reaction

Due to the depletion of fossil energy on earth, it is crucial to develop resource rich and efficient non-precious metal electrocatalysts for oxygen evolution reaction (OER). Herein, we synthesized an efficient and economical electrocatalyst using a simple self-assembly strategy. Firstly, rod-shaped MIL-88A was synthesized by hydrothermal method. Then, the surface of MIL-88A was functionalized and encapsulated in zeolitic imidazolate framework-67 (ZIF-67) by hydrothermal method. The combination of MIL-88A and ZIF-67 resulted in a slight ion-exchange reaction between Co2+ and the surface of MIL-88A to generate CoFe-LDH@ZIF-67 core-shell structure. Afterwards, in the presence of Mo6+, ZIF-67 was converted into CoMo-nanocages through ion-exchange reactions, forming a core-shell structure of MoCoFe hydr (oxy) oxide@CoMo-LDH (MoCoFe-HO@CoMo-LDH). Due to the advantages of core-shell structure and composition, this material exhibits excellent OER characteristics, with a small Tafel slope (45.11 mV dec-1) and low overpotential (324 mV) at 10 mA cm-2. It exhibits good stability in alkaline media. This research work provides a novel approach for the development of efficient and economical non-precious metal electrocatalysts.

Heterostructured Ag@MOF-801/MIL-88A(Fe) Nanocomposite as a Biocompatible Photocatalyst for Degradation of Reactive Black 5 under Visible Light

Heterostructured Ag@MOF-801/MIL-88A(Fe) nanocomposite was synthesized through template effects in metal-organic frameworks (MOFs). MIL-88A(Fe) was fabricated on a MOF-801 template using the internal extended growth method (IEGM) via polyvinylpyrrolidone (PVP) as the structure-director agent to create the MIL-88A(Fe)-on-MOF-801 heterostructure. The MOF-801/MIL-88A(Fe) heterostructure was used as a template for the formation of Ag nanoparticles (NPs) inside it via a double solvents method (DSM) combined with a photoreduction route (PR). To characterize synthesized samples to a high level of detail, PXRD, FT-IR, EDX, N2 adsorption-desorption isotherms, TEM, DRS, PL, EIS, and Mott-Sckottky measurements were used. The resulting Ag@MOF-801/MIL-88A(Fe) nanocomposite demonstrated the highest photocatalytic activity of 91.72% for the degradation of Reactive Black 5, after 30 min under visible light irradiation.

Application and Development Prospect of Nanoscale Iron Based Metal-Organic Frameworks in Biomedicine

Metal-organic frameworks (MOFs) are coordination polymers that comprise metal ions/clusters and organic ligands. MOFs have been extensively employed in different fields (eg, gas adsorption, energy storage, chemical separation, catalysis, and sensing) for their versatility, high porosity, and adjustable geometry. To be specific, Fe2+/Fe3+ exhibits unique redox chemistry, photochemical and electrical properties, as well as catalytic activity. Fe-based MOFs have been widely investigated in numerous biomedical fields over the past few years. In this study, the key index requirements of Fe-MOF materials in the biomedical field are summarized, and a conclusion is drawn in terms of the latest application progress, development prospects, and future challenges of Fe-based MOFs as drug delivery systems, antibacterial therapeutics, biocatalysts, imaging agents, and biosensors in the biomedical field.

One-step-one-pot hydrothermally derived metal-organic-framework-nanohybrids for integrated point-of-care diagnostics of SARS-CoV-2 viral antigen/pseudovirus utilizing electrochemical biosensor chip

The COVID-19 pandemic has become a global catastrophe, affecting the health and economy of the human community. It is required to mitigate the impact of pandemics by developing rapid molecular diagnostics for SARS-CoV-2 virus detection. In this context, developing a rapid point-of-care (POC) diagnostic test is a holistic approach to the prevention of COVID-19. In this context, this study aims at presenting a real-time, biosensor chip for improved molecular diagnostics including recombinant SARS-CoV-2 spike glycoprotein and SARS-CoV-2 pseudovirus detection based on one-step-one-pot hydrothermally derived CoFeBDCNH₂-CoFe₂O₄ MOF-nanohybrids. This study was tested on a PalmSens-EmStat Go POC device, showing a limit of detection (LOD) for recombinant SARS-CoV-2 spike glycoprotein of 6.68 fg/mL and 6.20 fg/mL in buffer and 10% serum-containing media, respectively. To validate virus detection in the POC platform, an electrochemical instrument (CHI6116E) was used to perform dose dependent studies under similar experimental conditions to the handheld device. The results obtained from these studies were comparable indicating the capability and high detection electrochemical performance of MOF nanocomposite derived from one-step-one-pot hydrothermal synthesis for SARS-CoV-2 detection for the first time. Further, the performance of the sensor was tested in the presence of Omicron BA.2 and wild-type D614G pseudoviruses.

Gelothermal Synthesis of Monodisperse MIL-88A Nanoparticles with Tunable Sizes and Metal Centers for Potential Bioapplications

Developing novel synthetic strategies to downsize metal-organic frameworks (MOFs) from polydisperse crystals to monodisperse nanoparticles is of great importance for their potential bioapplications. In this work, a novel synthetic strategy termed gelothermal synthesis is proposed, in which coordination polymer gel is first prepared and followed by a thermal reaction to give the monodisperse MOF nanoparticles. This novel synthetic strategy successfully leads to the isolation of Materials of Institute Lavoisier (MIL-88), Cu(II)-fumarate MOFs (CufumDMF), and Zeolitic Imidazolate Frameworks (ZIF-8) nanoparticles. Focused on MIL-88A, the studies reveal that the size can be well-tuned from nanoscale to microscale without significant changes in polydispersity index (PDI) even in the case of in situ metal substitution. A possible mechanism is consequently proposed based on extensive studies on the gelothermal condition including sol-gel chemistry, thermal condition, kinds of solvents, and so on. The unique advantages of monodisperse MIL-88A nanoparticles over polydisperse ones are further demonstrated in terms of in vitro magnetic resonance imaging (MRI), cellular uptake, and drug-carrying properties.

Facile synthesis of Co-Ni layered double hydroxides nanosheets wrapped on a prism-like metal-organic framework for efficient oxygen evolution reaction

The construction of low-cost oxygen evolution reaction (OER) electrocatalysts with high activity and good durability is a considerable challenge for facilitating the efficient utilization of green energy. Herein, the prism-like materials of institute lavoisier frameworks-88 (MIL-88) was first synthesized by a hydrothermal method. Then, Co-Ni layered double hydroxides (CoNi-LDHs) nanosheets were directly wrapped on the MIL-88 surface by electrodeposition to form core-shell MIL-88@CoNi-LDHs composites. Due to the distinct structure and synergistic effect between the MIL-88 core and CoNi-LDHs shell, it was found that MIL-88@CoNi-LDHs had outstanding OER activity with a small Tafel slope (45.55 mV dec^-1), low overpotential (314 mV) at 10 mA cm^-2, and superior durability. This study provides a prospective pathway to exploit highly efficient low-cost electrocatalysts for OER.

In Situ Electrospun Porous MIL-88A/PAN Nanofibrous Membranes for Efficient Removal of Organic Dyes

In recent years, metal-organic framework (MOF)-based nanofibrous membranes (NFMs) have received extensive attention in the application of water treatment. Hence, it is of great significance to realize a simple and efficient preparation strategy of MOF-based porous NFMs. Herein, we developed a direct in situ formation of MOF/polymer NFMs using an electrospinning method. The porous MOF/polymer NFMs were constructed by interconnecting mesopores in electrospun composite nanofibers using poly(vinylpolypyrrolidone) (PVP) as the sacrificial pore-forming agent. MOF (MIL-88A) particles were formed inside the polyacrylonitrile (PAN)/PVP nanofibers in situ during electrospinning, and the porous MIL-88A/PAN (pMIL-88A/PAN) NFM was obtained after removing PVP by ethanol and water washing. The MOF particles were uniformly distributed throughout the pMIL-88A/PAN NFM, showing a good porous micro-nano morphological structure of the NFM with a surface area of 143.21 m² g^-1, which is conducive to its efficient application in dye adsorption and removal. Specifically, the dye removal efficiencies of the pMIL-88A/PAN NFM for amaranth red, rhodamine B, and acid blue were as high as 99.2, 94.4, and 99.8%, respectively. In addition, the NFM still showed over 80% dye removal efficiencies after five adsorption cycles. The pMIL-88A/PAN NFM also presented high adsorption capacities, fast adsorption kinetics, and high cycling stabilities during the processes of dye adsorption and removal. Overall, this work demonstrates that the in situ electrospun porous MOF/polymer NFMs present promising application potential in water treatment for organic dyestuff removal.

Application of electrospun composite nanofibers as an efficient sorbent for extraction of pesticides from food samples

Herein, the composite of polylactic acid (PLA)/ Iron-based metal-organic framework (r-MIL-88A)/ Cellulose electrospun nanofibers was fabricated; and then, applied as a novel sorbent for thin-film micro-extraction (TFME) of four selected pesticides followed by GC-FID analysis. From the evaluation of scanning electron microscopy, Fourier transform infrared spectroscopy energy dispersive X-ray spectroscopy and X-ray diffraction, the successful fabrication of composite nanaofibers was approved. The presence of r-MIL-88A/Cellulose with large surface area and plenty of OH-functional groups results in improving PLA extraction efficiency. The effect of various main parameters on extraction efficiency was evaluated. The LODs (based on S/N = 3) were in the range of 1.0 to 1.5 ng mL^-1. Intra-day and inter-day relative standard deviations (RSDs) were in the range of 4.8% - 5.6% and 5.2%-6.4%, respectively. In addition, the fiber to fiber relative standard deviations were observed in the range of 5.2%-12.3%. By using the optimized factors, acceptable linearity ranges were obtained in the range of 3.0-1900.0 ng mL^-1 for metribuzin and ethofumasate, and 5.0-2000.0 for atrazine and ametryn (R² = 0.9913-0.9967). The developed method was investigated in fruit juice, vegetables, milk and honey samples, and recoveries (79.3-95.6%) indicate that the PLA/r-MIL-88A/Cellulose can be a prominent composite film for the extraction of the target analytes in various samples.

Efficient Removal of Inorganic and Organic Pollutants over a NiCo2O4@MOF-801@MIL88A Photocatalyst: The Significance of Ternary Heterojunction Engineering

Energy problems are a substantial concern in a global society that can be solved by replacing with sustainable energies. In recent years, designing nanomaterials as photocatalysts that can produce chemical energy with the utilization of infinite visible light energy became a new solution for water treatment. In the present study, NiCo₂O₄@MOF-801 has been synthesized with multiple properties, and then, a novel three-layer NiCo₂O₄@MOF-801@MIL88A photocatalyst has been successfully synthesized to improve meropenem degradation and Cr(VI) reduction. The prepared photocatalyst was characterized by XRD, IR, XPS, TEM, SEM, TGA, BET, EIS, PL, and UV-vis. According to the structural and optical analysis performed, the interaction between the components formed a heterojunction structure that prevented the recombination of charge carriers and increased the photocatalytic performance. Photocatalytic simulation tests also proved the reduction of chromium and degradation of antibiotics to find the optimal heterogeneous performance. As a result, the NiCo₂O₄@MOF-801@MIL88A composite can completely reduce Cr(VI) in 45 min, which is strongly preferable to any pure component's performance. Overall, this work offers a low-cost but high-efficiency material that can remove organic and inorganic contaminants from water.

Sustainable Ketalization of Glycerol with Ethyl Levulinate Catalyzed by the Iron(III)-Based Metal-Organic Framework MIL-88A

The catalytic properties of a simple iron-containing MOF based on fumaric acid, MIL-88A, were investigated in the ketalization of ethyl levulinate with glycerol. The corresponding product is a component of current interest as a renewable building block for many uses. Under the following conditions (solventless, 120 °C, stoichiometric ratio, 1% cat.), the reaction proceeds with good yields (85%), and the catalyst can be recovered and recycled without loss of activity, despite some changes in the crystalline lattice and morphology. Moreover, the residual iron content in the product is in the order of units of ppm (≤2), which demonstrates the robustness of the MOF under the reaction conditions.

Conductive substrates-based component tailoring via thermal conversion of metal organic framework for enhanced microwave absorption performances

Component tailoring, especially for the conductive substrates-based composites, acts as a significant role in optimizing the electromagnetic (EM) parameters and improving the EM response capability. Here, Fe-based metal oxides modified rGO microwave absorbers with component evolution were fabricated through hydrothermal treatment and subsequent pyrolysis process. The synergistic effects of the dielectric loss (multi-relaxations) and the magnetic loss (resonance and eddy current) are found to be effective in promoting the microwave absorption property of Fe_x-1O_x/C/rGO absorbers. As the thermal treatment temperature reaches 500 °C, the as-prepared composite sample shows ideal microwave absorption performance, where the reflection loss value is -25.94 dB, and the effective bandwidth reaches 5.84 GHz at 1.9 mm. In addition, CST simulation was employed to analyze the microwave absorption capability in the actual far field. When the scattering angle is 0° and 20°, the radar cross section (RCS) reduction of S-500/PEC layers is 8.11 dB m² and 8.80 dB m², respectively. This study exhibits the importance of component tailoring in enhancing the performances of substrates-based microwave absorption materials.

Controllable Heterojunctions with a Semicoherent Phase Boundary Boosting the Potassium Storage of CoSe2 /FeSe2

Heterostructure construction is an efficient method for reinforcing K⁺ storage of transition metal selenides. The spontaneously developed internal electric fields give a strong boost to charge transport and significantly reduce the activation energy. Nevertheless, perfection of the interfacial region based on the energy level gradient and lattice matching degree is still a great challenge. Herein, rich vacancies and ultrafine CoSe₂ -FeSe₂ heterojunctions with semicoherent phase boundary are simultaneously obtained, which possess unique electronic structures and abundant active sites. When employed as anodes for potassium-ion batteries (PIBs), CoSe₂ -FeSe₂ @C composites display a reversible potassium storage of 401.1 mAh g^-1 at 100 mA g^-1 and even 275 mAh g^-1 at 2 A g^-1 . Theoretical calculation also reveals that the potassium-ion diffusion can be dramatically promoted by the controllable CoSe₂ -FeSe₂ heterojunction.

Construction of Fe3O4-Loaded Mesoporous Carbon Systems for Controlled Drug Delivery

Magnetite (Fe₃O₄) nanoparticles as drug carriers can achieve precise drug target due to their magnetic property. However, they are easy to aggregate in the physiological environment, which obviously limits their application in drug delivery. The development of the Fe-MIL-88B-derived method to construct the Fe₃O₄-loaded mesoporous carbon (Fe₃O₄/carbon) system is a feasible strategy to solve the issue. First, iron atoms evenly distribute in the organic links through coordination bonds in Fe-MIL-88B. After the carbonization of Fe-MIL-88B, mesoporous carbon acts as a barrier to prevent the aggregation of Fe₃O₄ nanoparticles. Herein, Fe-MIL-88B particles were fabricated by the hydrothermal method and then pyrolyzed to construct Fe₃O₄/carbon systems. Results showed that Fe₃O₄ nanoparticles uniformly in situ grew on mesoporous carbon generated by the carbonization of organic components. More encouragingly, the Fe₃O₄/carbon system loaded with DOX demonstrated pH-responsive DOX release, efficient delivery of DOX into cancer cells, and significant cancer cell killing ability. Therefore, the Fe₃O₄/carbon systems prepared by the Fe-MIL-88B-derived method might open up a way for targeted and controlled drug delivery.

Phase transformation of iron oxide to carbide and Fe3C as an active center for the RWGS reaction

Fe3C was produced from iron oxide and identified as active and stable in the reverse water gas shift reaction.

A carbon-coated shuttle-like Fe2O3/Fe1-x S heterostructure derived from metal-organic frameworks with high pseudocapacitance for ultrafast lithium storage

Pursuing active, low-cost, and stable electrode materials with superior rate capability and long-life cycling performances for lithium-ion batteries remains a big challenge. In this study, a carbon-coated shuttle-like Fe2O3/Fe1-x S heterostructure is synthesized by simply annealing Fe-based metal-organic frameworks (MIL-88(Fe)) as precursors and sublimed sulfur. Carbon-coated Fe2O3/Fe1-x S displays a unique structure with ultrafine Fe2O3/Fe1-x S nanoparticles distributed in the hollow and porous carbon matrix, which offers a large specific surface area and fast charge transfer ability, and alleviates the volume change upon cycling. When evaluated as an anode material for lithium-ion batteries, it exhibits an ultra-high specific capacity of 1200 mA h g-1 at 0.1 A g-1, and superior high rate capability with a capacity of 345 mA h g-1 at a very high current density of 5.0 A g-1 owing to its high electrical conductivity and enhanced pseudocapacitive contribution from surface effects. The current strategy is promising to synthesize the carbon-coated porous structure from metal-organic frameworks for next-generation energy-storage applications.

Controlled pyrolysis of MIL-88A to prepare iron/carbon composites for synergistic persulfate oxidation of phenol: Catalytic performance and mechanism

In this study, based on the extensive discussion of the phase transformation process of metal-organic frameworks (MOFs)--MIL-88A(Fe) under thermal treatment, the catalytic performance of MIL-88A-derived iron/carbon (FexC) composites on persulfate (PS) activation for phenol degradation was investigated. FexC-600 (γ-Fe₂O₃/C) exhibited a superior catalytic activity on PS activation for phenol degradation due to higher carbon content, more sp²-hybridized structure, carbonyl group and defective sites in composites, in which 98.23% of phenol (20 mg/L) was degraded after 60 min with 0.3 g/L catalyst and 0.3 g/L PS at ambient pH (6.1). The phenol degradation experiments and mechanism studies revealed that there was a catalytic synergism between iron oxides and carbon component in FexC 400-600 composites. Moreover, sulfate radicals (SO₄^-), hydroxyl radical (•OH), singlet oxygen (¹O₂) and interfacial electron transfer process all involved in the degradation of phenol by FexC 400-600 composites, but the ¹O₂-mediated non-radical oxidation was the dominant pathway rather than reactive radicals. Finally, the possible mechanism of PS activation on FexC 400-600 composites was proposed. This work discusses the synergistic catalytic mechanism of FexC composites on PS activation, and favors to provide a better understanding of the metal species and carbon component interaction in iron/carbon-based materials.

Enhanced sodium storage kinetics by volume regulation and surface engineering via rationally designed hierarchical porous FeP@C/rGO

Transition metal phosphides, such as iron phosphide (FeP), have been considered as promising anode candidates for high-performance sodium ion batteries (SIBs) owing to their high theoretical capacity. However, the development of FeP is limited by large volume change, low electrical conductivity and sluggish kinetics with sodium ions. Moreover, the sodium storage kinetics and dynamics behavior in FeP are still unclear. Herein, improved sodium storage ability of FeP is achieved by volume regulation and surface engineering via a rationally designed hierarchical porous FeP@C/rGO nanocomposite. This FeP@C/rGO nanocomposite exhibits excellent rate capability and long cycle life as the anode of SIBs. Specifically, the FeP@C/rGO nanocomposite delivers high specific capacities of 635.7 and 343.1 mA h g-1 at 20 and 2000 mA g-1, respectively, and stable cycling with 88.2% capacity retention after 1000 cycles. The kinetics and dynamics studies demonstrate that the superior performance is attributed to the rationally designed hierarchical porous FeP@C/rGO with a high capacitive contribution of 93.9% (at 2 mV s-1) and a small volume expansion of only 54.9% by in situ transmission electron microscopy (TEM) measurement. This work provides valuable insights into understanding the phase evolution of FeP during the sodiation/desodiation process for designing high-performance SIBs.

Synergistically boosting the oxygen evolution reaction of an Fe-MOF via Ni doping and fluorination

An efficient approach to boost the oxygen evolution activity of Fe-MOF nanorods was demonstrated by a synergistic strategy of Ni doping and fluorination.

MOF-derived 1D hollow bimetallic iron(iii) oxide nanorods: effects of metal-addition on phase transition, morphology and magnetic properties

It is demonstrated that 1D hollow bimetallic iron oxide nanorods containing Mn, Ru, Ni, La and Ag ions can be obtained regardless of the different values of ionic radius and hardness of metal dopants from NH₄OH-etched MIL-88A MOF particles.

Simple Purification and Immobilization of His-Tagged Organophosphohydrolase from Cell Culture Supernatant by Metal Organic Frameworks for Degradation of Organophosphorus Pesticides

Coordinating unsaturated metal sites (CUS) on the surface of metal-organic frameworks (MOFs) could be used to adsorb His-tagged proteins. The specific adsorption between CUS and His-tagged proteins could reduce preparation steps, shorten preparation time, and could also avoid the binding between the metal ion of metalloenzyme active center and the chelating agent to ensure the enzyme activity. In this study, MIL-88A was synthesized by hydrothermal method and used to purify and immobilize His-tagged organophosphohydrolase (OpdA) in one step for organophosphate bioremediation. Under optimized conditions, OpdA@MIL-88A had a maximal activity of 1554 U/g_protein, which was nearly 5 times higher than free OpdA. Compared with free OpdA, OpdA@MIL-88A exhibited improved organic solvent tolerance, SDS tolerance, thermal stability, and storage stability. OpdA@MIL-88A was used to degrade organophosphorus pesticides on grapes and cucumbers. After reuse 6 times, OpdA@MIL-88A retained more than 66% and 61% of the initial activity, respectively. Therefore, this proposed strategy provided a facile and effective method for degradation of organophosphorus pesticides.

Hydrothermal Synthesize of HF-Free MIL-100(Fe) for Isoniazid-Drug Delivery

Sustainable development of drug delivery materials with good biocompatibility and controlled-release is a popular topic among researchers. In this research study, we demonstrated the potential of the metal-organic framework, that is MIL-100(Fe), as a drug delivery platform for isoniazid (INH). The MIL-100(Fe) was prepared by using the hydrofluoric acid-free hydrothermal method. Several physical measurements were conducted to characterize the MIL-100(Fe), including x-ray diffraction (XRD), scanning electron microscopy (SEM), nitrogen sorption, and thermal-gravimetric (TG). The synthesized MIL-100(Fe) has octahedron-shaped particles with superior properties, that is large surface area (1456.10 m2/g) and pore volume (1.25 cm3/g). The drug loading rate and capacity were determined by means of adsorption kinetic and isotherm. The studied INH@MIL-100(Fe) adsorption system kinetics follow the pseudo-first-order model, while the isotherm system follows the Langmuir model with the maximum adsorption capacity of 128.5 mg/g at 30 °C. MIL-100(Fe) shows adequate biocompatibility, also exhibits a reasonable and controlled drug release kinetics. The results obtained show that MIL-100 (Fe) can be a good choice of drug delivery platform among other available platforms.

Green synthesis of nitrogen-doped self-assembled porous carbon-metal oxide composite towards energy and environmental applications

Increasing environmental pollution, shortage of efficient energy conversion and storage devices and the depletion of fossil fuels have triggered the research community to look for advanced multifunctional materials suitable for different energy-related applications. Herein, we have discussed a novel and facile synthesis mechanism of such a carbon-based nanocomposite along with its energy and environmental applications. In this present work, nitrogen-doped carbon self-assembled into ordered mesoporous structure has been synthesized via an economical and environment-friendly route and its pore generating mechanism depending on the hydrogen bonding interaction has been highlighted. Incorporation of metal oxide nanoparticles in the porous carbon network has significantly improved CO₂ adsorption and lithium storage capacity along with an improvement in the catalytic activity towards Oxygen Reduction Reaction (ORR). Thus our present study unveils a multifunctional material that can be used in three different fields without further modifications.

Highly crystalline Ni-doped FeP/carbon hollow nanorods as all-pH efficient and durable hydrogen evolving electrocatalysts

Herein, we report the synthesis of uniform hollow nanorods of Ni-doped FeP nanocrystals hybridized with carbon as electrocataysts for the electrocatalytic hydrogen evolution reaction (HER). These hollow nanorods are prepared based on the etching and coordination reaction between metal-organic frameworks and phytic acid, followed by a pyrolysis process. Benefiting from the abundant active sites, the improved mass and charge transport capability, the optimized Ni-doped FeP/C hollow nanorods exhibit excellent HER activities for achieving a current density of 10 mA cm^-2 at an overpotential of 72, 117, and 95 mV in acidic, neutral, and alkaline media, respectively, as well as superior stability. X-ray photoelectron spectroscopy and basic density functional theory calculations suggest that the improved HER activity originates from the synergistic modulation of the active components, structural and electronic properties. This protocol provides a general and friendly strategy to construct hollow phosphides for energy-related applications.

Preparation, optimization and evolution of the kinetic mechanism of an Fe-MIL-88A metal–organic framework

Investigating the kinetics of crystallization, growth behavior and morphological changes through statistical studies of Fe-MIL-88A suggested an autocatalytic nucleation mechanism.

Immobilization of ssDNA on a metal–organic framework derived magnetic porous carbon (MPC) composite as a fluorescent sensing platform for the detection of arsenate ions

In this work, we fabricated a metal–organic framework derived magnetic porous carbon (MPC) and with ssDNA achieved specific and efficient recognition of harmful arsenate ions. The detection limit was achieved at 630 pM.

Mesoporous Metal-Organic Frameworks: Synthetic Strategies and Emerging Applications

Metal-organic frameworks (MOFs) have attracted much attention over the past two decades due to their highly promising applications not only in the fields of gas storage, separation, catalysis, drug delivery, and sensors, but also in relatively new fields such as electric, magnetic, and optical materials resulting from their extremely high surface areas, open channels and large pore cavities compared with traditional porous materials like carbon and inorganic zeolites. Particularly, MOFs involving pores within the mesoscopic scale possess unique textural properties, leading to a series of research in the design and applications of mesoporous MOFs. Unlike previous Reviews, apart from focusing on recent advances in the synthetic routes, unique characteristics and applications of mesoporous MOFs, this Review also mentions the derivatives, composites, and hierarchical MOF-based systems that contain mesoporosity, and technical boundaries and challenges brought by the drawbacks of mesoporosity. Moreover, this Review subsequently reveals promising perspectives of how recently discovered approaches to different morphologies of MOFs (not necessarily entirely mesoporous) and their corresponding performances can be extended to minimize the shortcomings of mesoporosity, thus providing a wider and brighter scope of future research into mesoporous MOFs, but not just limited to the finite progress in the target substances alone.

Thermal Instability Induced Oriented 2D Pores for Enhanced Sodium Storage

Hierarchical porous structures are highly desired for various applications. However, it is still challenging to obtain such materials with tunable architectures. Here, this paper reports hierarchical nanomaterials with oriented 2D pores by taking advantages of thermally instable bonds in vanadium-based metal-organic frameworks (MOFs). High-temperature calcination of these MOFs accompanied by the loss of coordinated water molecules and other components enables the formation of orderly slit-like 2D pores in vanadium oxide/porous carbon nanorods (VO_x /PCs). This unique combination leads to an increase of the reactive surface area. In addition, optimized VO_x /PCs demonstrate high-rate capability and ultralong cycling life for sodium storage. The assembled full cells also show high capacity and cycling stability. This report provides an effective strategy for producing MOFs-derived composites with hierarchical porous architectures for energy storage.

Nanoarchitectured Design of Porous Materials and Nanocomposites from Metal-Organic Frameworks

The emergence of metal-organic frameworks (MOFs) as a new class of crystalline porous materials is attracting considerable attention in many fields such as catalysis, energy storage and conversion, sensors, and environmental remediation due to their controllable composition, structure and pore size. MOFs are versatile precursors for the preparation of various forms of nanomaterials as well as new multifunctional nanocomposites/hybrids, which exhibit superior functional properties compared to the individual components assembling the composites. This review provides an overview of recent developments achieved in the fabrication of porous MOF-derived nanostructures including carbons, metal oxides, metal chalcogenides (metal sulfides and selenides), metal carbides, metal phosphides and their composites. Finally, the challenges and future trends and prospects associated with the development of MOF-derived nanomaterials are also examined.

Nano Metal-Organic Framework-Derived Inorganic Hybrid Nanomaterials: Synthetic Strategies and Applications

Nano- (or micro-scale) metal-organic frameworks (NMOFs), also known as coordination polymer particles (CPPs), have received much attention because of their structural diversities and tunable properties. Besides the direct use, NMOFs can be alternatively used as sacrificial templates/precursors for the preparation of a wide range of hybrid inorganic nanomaterials in straightforward and controllable manners. Distinct advantages of using NMOF templates are correlated to their structural and functional tailorability at molecular levels that is rarely acquired in any other conventional template/precursor. In addition, NMOF-derived inorganic nanomaterials with distinct chemical and physical properties are inferred to dramatically expand the scope of their utilization in many fields. In this review, we aim to provide readers with a comprehensive summary of recent progress in terms of synthetic approaches for the production of diverse inorganic hybrid nanostructures from as-synthesized NMOFs and their promising applications.

Heterogeneous Fenton-like catalysis of Fe-MOF derived magnetic carbon nanocomposites for degradation of 4-nitrophenol

Magnetic Fe–C_x as heterogeneous Fenton-like catalysts were synthesized by the pyrolysis of Fe-MOF, and the catalytic activity of Fe–C_x for removal of 4-NP was significantly affected by pyrolysis temperature.