Hybrid Metal Organic Frameworks Research Articles

Sunlight assisted highly efficient desorption of ammonia by redox graphene hybrid metal–organic framework photothermal conversion adsorbents

The capture, storage and release of NH3 play a pivotal role in sustainable energy applications. However, to simultaneously achieve high adsorption capacity and low energy desorption remains a challenge. In this work, a novel class of hybrid materials with photothermal conversion performance have been developed by doping redox graphene and metal–organic framework of MOF-303(Al). It is found that the optimized rGO@MOF-303(Al)-8% exhibits high NH3 uptake (17.0 mmol g−1) at 25.0 °C and 1.0 bar and exceptional photothermal conversion performance. Under the irradiation of simulated sunlight, its temperature can be raised to about 75 °C in 10 min. Even under direct natural sunlight irradiation, a stable equilibrium temperature of 53 °C may be achieved. Based on this excellent photothermal conversion performance, we investigated the desorption behavior of ammonia under visible light irradiation for the first time. We found that due to the breakdown of hydrogen bonds of NH3 and N-N, N–H sites of rGO@MOF-303(Al)-8% caused by the rapid rise of temperature, approximately 68% of NH3 could be effectively desorbed in 2-hour irradiation under ambient conditions. In addition, the optimized adsorbent demonstrated remarkable cycling stability. After undergoing 10 cycles, high adsorption capacity and efficient light-induced desorption of NH3 were still maintained Thus, the present study provides a novel concept for high-capacity adsorption and low-energy desorption of NH3 and other industrial gases.

A sustainable lecithin-based ligand for the bio-functionalization of iron and hybrid Metal Organic Framework nanoparticles with mannose

The functionalization of nanoparticles with specific ligands, such as antibodies, peptides, and small molecules, plays a critical role in achieving targeted delivery, enhancing biocompatibility, and controlling drug release. However, to...

A polymer deposition-mediated surface-charge reformation strategy: reversing the MOF biomineralization behavior.

Biomineralization of a porous metal-organic framework (MOF) shell onto biomacromolecule templates is a burgeoning strategy to construct robust biocatalysts. However, it strongly relies on the interfacial interaction between MOF precursors and enzyme surface, significantly limiting the generalization of this nanotechnology. Herein, we identify polymers that are well-suited for deposition onto target biomacromolecules via supramolecular interactions and introduce a polymer deposition-mediated surface-charge reformation strategy to facilitate the biomineralization of porous MOFs, including ZIF-8, ZIF-90, and ZIF-zni onto enzymes. We investigate nine commercially available polymers to find that those with dense -SO3H and -COOH groups effectively regulate the surface-charge properties of the enzymes that are unfavorable for biomineralization. The polymer-enzyme complex thus formed retains its original bioactivity and offers significantly elevated sites to accumulate metal precursors, triggering the in-place MOF biomineralization. We demonstrate that this approach allows access to diverse MOF biocatalysts independent of the enzyme surface chemistry, which are difficult to be synthesized by previous biomineralization methods. Given the highly specific bioactivity and structural stability of the MOF biocatalysts, a chemiluminiscence sensor platform is developed for the sensitive detection of hydrogen sulfide (H2S) biomarkers, with a low limit of detection of 0.09 nM that is superior to most of the reported methods. This study provides an effective and universal strategy for MOF biomineralization using fragile enzymes as biotemplates and offers new insights into accessing multifunctional MOF hybrid biocatalysts.

Graphene and metal-organic framework hybrids for high-performance sensors for lung cancer biomarker detection supported by machine learning augmentation.

Conventional diagnostic methods for lung cancer, based on breath analysis using gas chromatography and mass spectrometry, have limitations for fast screening due to their limited availability, operational complexity, and high cost. As potential replacement, among several low-cost and portable methods, chemoresistive sensors for the detection of volatile organic compounds (VOCs) that represent biomarkers of lung cancer were explored as promising solutions, which unfortunately still face challenges. To address the key problems of these sensors, such as low sensitivity, high response time, and poor selectivity, this study presents the design of new chemoresistive sensors based on hybridised porous zeolitic imidazolate (ZIF-8) based metal-organic frameworks (MOFs) and laser-scribed graphene (LSG) structures, inspired by the architecture of the human lung. The sensing performance of the fabricated ZIF-8@LSG hybrid sensors was characterised using four dominant VOC biomarkers, including acetone, ethanol, methanol, and formaldehyde, which are identified as metabolomic signatures in lung cancer patients' exhaled breath. The results using simulated breath samples showed that the sensors exhibited excellent performance for a set of these biomarkers, including fast response (2-3 seconds), a wide detection range (0.8 ppm to 50 ppm), a low detection limit (0.8 ppm), and high selectivity, all obtained at room temperature. Intelligent machine learning (ML) recognition using the multilayer perceptron (MLP)-based classification algorithm was further employed to enhance the capability of these sensors, achieving an exceptional accuracy (approximately 96.5%) for the four targeted VOCs over the tested range (0.8-10 ppm). The developed hybridised nanomaterials, combined with the ML methodology, showcase robust identification of lung cancer biomarkers in simulated breath samples containing multiple biomarkers and a promising solution for their further improvements toward practical applications.

Modification sub-nano Zn-Co Metal-Organic framework for electrochemical detection of neurotransmitter

We developed a novel platform that was constructed using an in-situ technique to simultaneously synthesize sub-nano Zn-Co on the metal–organic framework (MOF) with a dodecahedron size of 150 nm. The hybridization structure of sub-nano Zn-Co MOF has been demonstrated through shifts of diffraction peaks (XRD patterns) and shake-up satellite peaks, shifting negativity of metallic Co (XPS spectra). The electrochemical dopamine (DA) sensing mechanism was thoroughly analyzed. The sub-nano Zn-Co MOF hybrid material has shown excellent electrochemical results in detecting DA detection at extremely low concentrations. Results from DPV showed that the Zn-Co MOF/GCE has a linear range of 0.01–300 µM of DA and a limit of detection of 6.72 nM. The interference experiments of neurotransmitters (UA, GABA, AA, Gly, Ser) demonstrated not much effect on amperometry changes of DA. Especially, sub-nano Zn-Co MOF/GCE electrode indicated good results in the serum samples, high reproducibility, and can practical application. With advantages including a simple, environmentally friendly, non-enzymatic production process, high selectivity, and reproducible outcomes, DA-detecting sub-nano Zn-Co MOF that has been developed can be used for the initial diagnosis of neurological disorders, the functional evaluation of dopaminergic neurons, chemicals or drugs on human neuronal cells.

Synthesis of metal-organic framework hybrid nanocomposites based on MOFs@C3N4 with high selective separation ability for luteolin

Complex substrates found in certain extracts-particularly those containing high phenolic compounds with significant medicinal value-pose considerable challenges to developing molecularly imprinted membranes (MIMs) with specific recognition abilities. In this study, UiO-66-NH2, a metal–organic structure (MOF), was chosen as an optimizer to enhance the basic support material C3N4. A composite imprinted membrane based on MOFs was then prepared for the targeted adsorption of luteolin (LTL). This not only increases the surface area and pore capacity of the composite membranes, but also ensures unprecedented control over the membranes structure and good stability. To maximize the proportion of imprinted sites, we utilize an advanced boron affinity sol–gel imprinting technique that capitalizes on the exceptional response of the bifunctional monomer. By finely manipulating the imprinting process, controlled distribution of imprinted sites was achieved. Furthermore, the incorporation of Ag nanoparticles into the composite matrix of MIMs enhances selectivity and efficiency due to their plasmonic properties and high affinity for phenolic compounds, providing increased adsorption surface area and additional binding sites. The results showed satisfactory rebinding ability (56.25 mg g−1) and superselective (βAG/LTL = 4.43 and βCT/LTL = 8.49). It was worth noting that incorporating Ag nanoparticles into composite MIMs for the selective adsorption of LTL demonstrates significant potential. This includes enhanced selectivity, efficiency, and hydrophilicity of the membrane surface. Thus, enhanced hydrophilicity can establish stronger non-covalent interactions, namely hydrogen bonding and van der waals forces, with the target molecules, thereby significantly improving the adsorption capacity of the MIMs. The feasibility of this method was demonstrated via in-situ infrared analysis of the chemical structure changes before and after adsorption.

Accelerating Uranium Extraction from Water via Synergy of Adsorption and Filtration by MOF Hybrid Membrane

AbstractIn this paper, novel UiO‐66‐AO‐based adsorption‐filtration hybrid membranes (UAMs) are prepared via an irradiation‐mediated growth strategy to simultaneously improve water flux and accelerate uranium extraction from water resources. The UAM shows an equilibrium adsorption that is four times faster than UiO‐66‐AO powder and an adsorption capacity that is over two times higher. UAM also achieves a record synergy of high flux and high uranium removal ratio from simulated seawater (1358.8 L m−2 h−1, 84.5%) by one‐time filtration under ambient temperature and pressure (the adsorption is 1.83 mg g−1 in 90 min). The excellent uranium extraction performance is attributed to the unique UAM structure, in which water flows through the channels of thin metal‐organic framework (MOF) film without blocking by substrate leading to the high flux during filtration, and the full contact of uranium with abundant exposed active sites promotes the adsorption. This work will be conducive to overcoming the bottleneck problems of uranium extraction from water resources.

Block Copolymer‐Stabilized Metal–Organic Framework Hybrids Loading Pd Nanoparticles Enable Tumor Remission Through Near‐Infrared Photothermal Therapy

Metal–organic frameworks (MOFs), such as the magnetic resonance imaging‐fit MIL‐100 based on Fe, are gaining significant attention as versatile theranostics with high‐loading capability. Moreover, as MOFs can be engineered to target tumors, there is much interest in applying them for precise pin‐point treatment of cancer. Herein, Pd nanoparticles within MIL‐100(Fe) are generated to create MOFs with remarkable photothermal conversion properties for cancer therapy. The Pd‐loaded MIL‐100(Fe) (Pd@MIL‐100(Fe)) are stabilized with biocompatible block copolymers to generate MOFs with PEGylated surfaces. This is achieved by directly mixing poly(ethylene glycol)‐poly(L‐aspartic acid) (PEG‐p(Asp)) or dopamine‐modified PEG‐p(Asp) (PEG‐p(Asp‐Dopa)) block copolymers with the MOFs in aqueous conditions. The resulting block copolymer‐stabilized MOF hybrids are stable in physiological conditions. Particularly, the Pd@MIL‐100(Fe)/PEG‐p(Asp‐Dopa) hybrids show enhanced blood circulation and increased accumulation in B16F10 melanoma. Furthermore, when irradiated with 808 nm light, the Pd@MIL‐100(Fe)/PEG‐p(Asp‐Dopa) hybrids rapidly increase the temperature to 50 °C, enabling tumor remission. The surface‐stabilized Pd@MIL‐100(Fe)/polymer hybrids open viable opportunities for innovating MOF/polymer hybrid‐based approaches for drug delivery.

Semiconductive (Cu–S)n Metal–Organic Frameworks Hybrid Polyaniline Nanocomposites as Hydrogen Sulfide Gas Sensor

A semiconductive (Cu–S)n metal–organic framework (MOF) incorporated polyaniline (PANI) nanocomposite was applied for hydrogen sulfide (H2S) gas sensing. The (Cu–S)n MOF nanosheets were successfully synthesized using a one-pot reflux method. First, fiber-like (Cu–S)n MOF/ PANI nanocomposites were prepared through an in situ oxidative polymerization. As evaluated by field-emission transmission electron microscopy (FE-TEM), the nanosized spherical (Cu–S)n MOF particles were well-distributed in the fiber matrix. Then, the nanocomposite was spin-coated onto an interdigitated electrode (IDE) for H2S gas sensing, displaying high sensitivity, selectivity, repeatability, and stability similar to pure PANI. As a result, 3wt% (Cu–S)n MOF/ PANI nanocomposite showed the best performance for H2S detection. The mechanism for improving H2S sensing performance might be attributed to the conductive composite networks' significantly enhanced conductivity and increased doping sites of the (Cu–S)n MOF. In addition, the energy band gaps of PANI-based nanocomposites were optimized by the incorporated (Cu–S)n MOF, indicating the successful hybridization of energy levels between inorganic MOF and organic PANI. This study first demonstrates semiconductive MOF-PANI-based nanocomposites for H2S gas sensing.

Hierarchical Amino-Functionalized Ionic Liquids@MOF Composite Gel for Catalytic Conversion of CO2.

Hybridization of metal-organic frameworks (MOFs) and homogeneous ionic liquids (ILs) endows the heterogeneous composite with high porosity and accessible multiple active sites (e.g., acidic or basic sites), which exhibits great potential in CO2 capture and conversion. Nevertheless, the majority of MOF composites are synthesized as powders, significantly restricting their practical applications due to inherent problems such as poor handling properties, high pressure drops, and mechanical instability. Thus, it is crucial to shape MOF composites into various monoliths that allow efficient processing, especially for industrial purposes. In this work, a hierarchical ILs@nanoMOF composite gel (H-IL@UiO-66-gel) featuring both intraparticle micropores and interparticle mesopores and multiple active sites was successfully fabricated by a two-step approach. Benefiting from the integrated advantages of the hierarchically porous MOF for enhanced mass transfer and affinity of ILs for activating CO2 molecules, the resultant H-IL@UiO-66-gel exhibits excellent uptake of macromolecules and catalytic activity toward CO2 cycloaddition with epoxides under moderate conditions, far beyond the traditional microporous IL@UiO-66-gel and unfunctionalized H-UiO-66-gel. Furthermore, the H-IL@UiO-66 composite monolith can be effortlessly separated and reused at least three times without depletion of catalytic activity. It is believed that this fabrication method for the shaping of MOF composites is highly versatile and can be extended to other types of MOFs for various application fields.

A series of formic acid MOFs/polylactic acid blending composites with the improved dielectric performance in Co(II) systems

In order to improve the limited compatibility of existing polymer/ceramic dielectric composites and further enhance the energy storage density, MOF/polymer composite dielectrics have been explored, which exhibit good compatibility to the polymer matrix from abundant organic groups of the inorganic–organic hybrid metal-organic framework (MOF) fillers. However, they still lack a clear composition–structure–property rule, and the precise design of MOF fillers and polymer matrix becomes a prominent problem in these composites due to the diversity of the metal ions and the organic groups. Thus, in this paper, we present a series of formic acid MOFs/polylactic acid dielectric composites in which ferroelectric formic acid MOFs, namely PDLLA/[NH[Formula: see text](CH[Formula: see text])[Formula: see text]NH[Formula: see text]][M[Formula: see text](HCOO)[Formula: see text]][Formula: see text] and PDLLA/[CH[Formula: see text]NH[Formula: see text]][M[Formula: see text](HCOO)[Formula: see text]][Formula: see text], in which the formic acid MOFs are with different structures and different metal ions as fillers, including [NH3(CH[Formula: see text]NH3][MII(HCOO)3]2 (namely MOF– Co (M [Formula: see text] Co), MOF– Mg(M [Formula: see text] Mg), MOF– Mn (M [Formula: see text] Mn), with 1, 4-butanediamine ion as guest) and [CH3NH3][M[Formula: see text](HCOO)3]2 (namely MOF– Co[Formula: see text] (M = Co), MOF– Ni[Formula: see text] (Ni), with methylamine ion as guest). The composition and morphology of composite films were characterized by XRD, IR, SEM, DSC and UV, respectively, while the dielectric characterizations of the composites including the dielectric permittivity, the dielectric loss, the breakdown field strength and the energy density were also performed. The composition–structure–property relationships were also investigated including the influence of MOF content and MOF category. With the introduction of MOFs, the dielectric constant of the polylactic acid substrate was improved slightly while the breakdown field strength can be improved in some systems. Interestingly, the Co(II)-containing formic acid MOF has advantages over other formic acid MOFs with similar structure for the enhancement of the dielectric constant and breakdown field strength. Also, in some composite films with methylamine ion guest MOF fillers and low-MOF content ( MOF– Co[Formula: see text] (1 vol.%) and MOF– Ni[Formula: see text] (1 vol.%)), the breakdown electric field enhanced significantly and further led to improved energy storage density which was about 43% higher than that of the polylactic acid matrix. The possible reason is that in these composites, the orientation of C–H bonds of MOFs seems more beneficial to the formation of hydrogen bonds between the carboxyl group of formic acid and the polylactic acid matrix. These relationships obtained from formic acid MOFs/polylactic acid composites are valuable to the design of high-performance polymer/MOF energy storage composites and may be a new perspective to the practical use of ferroelectric MOFs.

Synchronous wrapping and inward-etching strategy on constructing yolk-shell MIL-88A@NiFe-PB heterostructures for electrochemical non-enzymatic glucose detection

Construction of heterocompositional hybrid metal–organic frameworks (MOFs) by integration of more than two MOFs is a smart strategy for fine-tuning MOF properties. In this work, a novel yolk-shell MIL-88A@NiFe-PB heterostructure, in which MIL stands for Materials from Institute Lavoisier, and PB represents the coordination network of Prussian Blue, was fabricated through a fast wrapping and then inward-etching growth synthetic strategy under mild stirring condition. The thickness of the outmost layer of NiFe-PB and the internal core structure of MIL-88A can be controlled by tuning the concentration of K4[Fe(CN)6]·3H2O in the assembly system. A rational growth mechanism for the yolk-shell MIL-88A@NiFe-PB heterostructure was proposed. The as-prepared yolk-shell MIL-88A@Ni10Fe PB-50 architectures were then explored for non-enzymatic glucose sensing. The results show that the designed glucose sensor exhibits a high sensitivity of 1963.2 μA mM−1 cm−2 over a wide linear range of 0.005–1.0 mM, a low detection limit (0.12 μM), as well as a fast reaction time (<2 s) and long-term stability for non-enzymatic glucose detection. Also, it shows good applicability in real serum samples. This work provides a “wrapping-inward-etching” synthetic strategy for construction of hybrid MOFs with exceptional outstanding non-enzymatic glucose sensing performance, providing a reasonable guide for construction of other MOF on MOF intriguing structures for electrochemical sensing applications.

Azo-Linkage Redox Metal-Organic Framework Incorporating Carbon Nanotubes for High-Performance Aqueous Energy Storage.

The design of well-defined hierarchical free-standing electrodes for robust high-performance energy storage is challenging. We report herein that azo-linkage redox metal-organic frameworks (MOFs) incorporate single-walled carbon nanotubes (CNTs) as flexible electrodes. The in situ-guided growth, crystallinity and morphology of UiO-66-NO2 MOFs were finely controlled in the presence of CNTs. The MOFs' covalent anchoring to CNTs and solvothermal grafting anthraquinone (AQ) pendants endow the hybrid (denoted as CNT@UiO-66-AQ) with greatly improved conductivity, charge storage pathways and electrochemical dynamics. The flexible CNT@UiO-66-AQ displays a highest areal specific capacitance of 302.3 mF cm-2 (at 1 mA cm-2) in -0.4~0.9 V potential window, together with 100% capacitance retention over 5000 cycles at 5 mA cm-2. Its assembled symmetrical supercapacitor (SSC) achieves a maximum energy density of 0.037 mWh cm-2 and a maximum power density of 10.4 mW cm-2, outperforming many MOFs-hybrids-based SSCs in the literature. Our work may open a new avenue for preparing azo-coupled redox MOFs hybrids with carbaneous substrates for high-performance robust aqueous energy storage.

Incorporated ferrocene-derivatives endow Ni-based MOF with high-performance for electrochemical detection

Metal-organic frameworks (MOFs) exhibit structural diversity and functional tunability, rendering them a versatile platform for a wide range of applications. Specifically, defects or function groups induced by exotic ligands is an efficient strategy to adjust the catalytic performance. In this study, we explore the impact of incorporating ferrocene derivatives into two Ni-based MOFs and examine their suitability as potential glucose sensors. One strategy involves introducing bidentate 1,1′-ferrocenedicarboxylic acid (1,1′-Fc) into the 3D Ni-1,4-benzenedicarboxylic acid MOF (Fc-Ni-BDC) using a simple single-step hydrothermal method. Another approach involves encapsulating ferrocenemethylamine (Fc-NH2) inside the cavity of 2D conductive Ni-HHTP MOF (HHTP=2,3,6,7,10,11-hexahydroxytriphenylene) driven by electrostatic attraction to form Fc-Ni-HHTP. On account of the synergy between ferrocene derivatives and MOFs, the hybrid MOFs demonstrated remarkable electrochemical performance, characterized by pronounced electrocatalytic reactivity towards glucose oxidation. It is showed that the doped ferrocene derivatives act as electron donors to the MOF active sites, modifying the electronic structure and facilitating the kinetics of the reactions, then an augmentation in the catalytic efficiency has been achieved. This work demonstrates a simple strategy to improve MOF-based electrochemical sensors by incorporating metallocene ligands.

Synthesis and Evaluation of Pristine Co and Hybrid Ni-Co Metal-Organic Frameworks (MOFs) as Potential Electrodes for Electrochemical Energy Storage Applications

Hybrid metal-organic frameworks (MOFs) have many positive features like high porosity, surface area, and conductivity as compared to other materials. They have better potential than pristine ones due to the reason that hybrid materials have good faradic responses due to variable metal oxidation states. These all-favorable factors make hybrid MOFs more potential electrodes for energy storage. In this study, hybrid Ni-Co MOFs presented good specific capacitance of 745 F g-1 (447 C g-1 @ 1 A g-1) in comparison with pristine Co MOFs of 109 F g-1 (65.5 C g-1 @ 1 A g-1). Also, the hybrid MOFs showed superior electrical conductivity of 1353.3 S cm-1 as compared to pristine MOFs. The charge transfer resistance (Rct) of hybrid MOFs was 2.271 Ω pretty much greater than pristine MOF and other closely related studies. The best electrochemical performance was attributed to the synergic effect of Ni, Co, and organic ligand.

Labeled free electrochemiluminescence aptamer platform based on one-step cathodic electrochemical growth of 2D/3D Ru-BTC-MOFs nanoparticles to detect carcinoembryonic antigen

[Ru(dcbpy)3]2+ functionalized 2D/3D hybrid metal–organic frameworks (Ru-BTC-MOFs), which performed good ECL performance, were synthesized by on one-step cathodic electrodeposition with Zn(NO3)2 as metal ion source, Ru(dcbpy)3Cl2) (tri(4,4-dicarboxybipyridine) ruthenium chloride) and H3BTC (1,3,5-phenyl tricarboxylic acid) as organic ligand. The effect of electrodeposition voltage, electrodeposition time, H3BTC and [Ru(dcbpy)3]Cl2 concentration on the morphology and ECL performance of Ru-BTC-MOFs were investigated in detail. An ECL biosensor platform for sensitive detection of carcinoembryonic antigen (CEA) was constructed by further modified AuNPs and aptamer on the Ru-BTC-MOFs/GCE. The specifically recognition and adsorption of CEA would hinder the electron transfer between Ru-BTC-MOFs and trinpropylamine (TPA) as the co-reactive agent, resulting in decreasing the ECL intensity. Under the optimal experimental conditions, the ECL intensity and logarithm of CEA concentration showed a good linear relationship in the concentration range of 10.0 fg/mL to 10.0 ng/mL, and the detection limit was 5.56 fg/mL. The proposed sensor performed acceptable reproducibility, repeatability, anti-interference ability and stability, and it would be expected to have broad application prospects in clinical trials.

A ROS reservoir based on a polyoxometalate and metal-organic framework hybrid for efficient bacteria eradication and wound healing

Infections by bacteria always post significant challenges to global human health. Recent developed non-antibiotic treatment, such as using metal–organic frameworks (MOFs) to kill bacteria by generating reactive oxygen species (ROS) represents a promising strategy. However, drawbacks including low efficiencies of ROS generation and high concentrations of toxic metal ions released always exist. We have creatively designed a robust polyoxometalate (POM) and MOF hybrid (denoted as CuPOM-MOF@S) that functions as an efficient catalytic reservoir for cascaded generation of ROS (mainly ·OH) from H2O2 thus eradicating bacteria and enhancing wound healing at an administration dosage as low as 5 μg∙mL−1. The remarkable antibacterial capability surpasses those for most MOF-based materials reported thus far, which is mainly attributed to the reservation of massive catalytic copper ions, the synergistic effect regarding catalytic activity between MOFs and Keggin-type POMs as well as its bacteria-capturing ability by the coated surfactants. Its biological safety is investigated and confirmed by cell cytotoxicity and body weight assessment. This work presents a prospective strategy towards cascaded ROS generation by combining inorganic catalytic POMs with MOFs thus for multiple biomedical applications including treating bacterial infections and cancer as well as inducing biological signal responses.

Pd on composite chitosan bead containing a star-like hybrid metal-organic framework: A promising catalyst for hydrogenation of lubricants

A star-like hybrid composite of metal-organic framework with amino-functionalized Fe-based metal-organic framework and zeolitic imidazolate framework components was synthesized, characterized and then embedded in chitosan beads. The beads were cross-linked with glutaraldehyde to furnish robust beads, which were then utilized as supporting materials for stabilizing Pd nanoparticles. The obtained catalytic composite was characterized via XRD, FTIR, TGA, ICP, SEM, EDS, elemental mapping and utilized for the hydrogenation of polyalphaolefin oil. The effects of temperature, catalyst loading and hydrogen pressure were investigated to find the best reaction conditions. According to the results, the present catalyst promoted hydrogenation reaction under relatively mild conditions (P = 8 bar, T = 130 °C and 5 wt% catalyst loading) to give the product in 98% yield and bromine index of 50 mg-Br/100 g. Besides, the catalyst exhibited acceptable recyclability and insignificant Pd leaching, which is very promising for large-scale applications. Hot filtration test also affirmed heterogeneous catalysis.

High performance Hetero-Shelled hollow structure Metal-Organic framework hybrid material for the efficient electrochemical determination of lead ions

Electrochemical sensing has unique advantages in developing on-site and online detection technologies for heavy metal ions (HMIs) due to its fast response, simple operation, high sensitivity, and portable instruments. The vigorous development of modern micro/nanomaterial preparation technology has provided greater space for improving the performance of electrochemical sensing platforms. In this work, a novel hetero-shelled hollow structure metal–organic framework (MOF) hybrid material (denoted as HCZ@UN) was prepared by adopting the hollow carbonized ZIF-8 (HCZ) as the substrate for growing UiO-66(Zr)–NH2 (UN), and subsequently used for efficient electrochemical detection of lead ions (Pb2+). The grown UN crystal particles were anchored on the HCZ hollow cages and showed nanometer size. The unique shell structure and nanometer size of UN created large specific surface area and rich accessible adsorption sites, which promoted the preconcentration of Pb2+. While the hollow carbon polyhedron structure of HCZ improved the dispersibility of UN and electron transfer ability of the material. These factors synergistically improved the detection sensitivity and sensing performance for Pb2+ determination with a wide linear range of 0.100–500 nM, a low detection limit of 0.0492 ± 0.00523 nM as well as good selectivity, repeatability and long-term stability. This paper provides a simple and effective method for the preparation of electroactive MOF functional materials, which is expected to inspire more interest in building other MOF-based materials with unique structure, high-performance and extensive application value.

MOF-derived Co-C composites with 3D star structure for enhanced microwave absorption

The demand of microwave absorption materials (MAMs) with unique morphologies and electromagnetic (EM) balance has become necessary in recent years. Due to the ease of synthesis and tunable structure, metal–organic frameworks (MOFs) are widely used for this special MAMs. In this study, a new three-dimensional hybrid MOF is proposed that is co-doped with six equally branched star morphologies. The Co-C composite has the same six-branched morphology as that of the precursor. When the EM wave is incident, this special structure makes it easier for the EM wave to enter the material vertically due to the expansion of the incident surface, which is effective in adjusting the transmission path of the electron and the reflection and distribution of the EM wave. Because of the special morphology and magneto-dielectric synergy, the Co-C composite shows a minimum reflection loss (RLmin) of −48.5 dB at 11.0 GHz at an absorption thickness of 3.0 mm, with a microwave absorption bandwidth (EAB) of 6.1 GHz. This research provides a practical guidance for preparing the MAMs of special star structure.