Metal-organic Framework Composites Research Articles

Recent research progress of MOFs-based heterostructures for photocatalytic hydrogen evolution

The growing serious energy crisis and environmental pollution expedite the development of green hydrogen energy. Photocatalytic water splitting technology, converting solar energy into chemical energy directly, provides a clean and economical way for hydrogen evolution. For the past few years, metal–organic frameworks (MOFs) semiconductor materials have become a research hotspot in the field of photocatalytic hydrogen evolution (PHE) due to their multiple advantages, including adjustable structure, high porosity, large specific surface area, abundant active sites, and so forth. Besides this, the construction of heterogeneous structures based on MOFs materials can further improve PHE performance through the effective internal electric field directional transfer of photogenerated electrons and the superior utilization rate of sunlight in comparison to the single MOFs photocatalyst. Herein, in this minireview, we summed up the varieties of synthesis methods of diverse types of MOFs heterojunction complex materials, discussed the H2 evolution efficiency based on this heterostructure photocatalyst in detail, and lastly proposed the advantages, limitations, and outlook of MOFs composites in the PHE field. We sincerely hope this review can provide a reference for future research based on MOFs materials for alleviating the current energy crisis.

Development of a Multiparticulate Metal-Organic Framework/Textile Fiber Swatch.

The versatility of metal-organic frameworks (MOFs) has led to groundbreaking applications in a wide variety of fields, especially in the areas of energy, environment, and sustainability. For example, MOFs can be designed for high uptake of toxic gases and pollutants, such as CO2, NH3, and SO2, but designing a single MOF that shows tangible uptake for all of these gases is challenging due to the differences in the chemical and physical properties of these molecules. To this end, integrating multiple MOFs onto textile fibers and crafting various structures have emerged as pivotal developments, enhancing framework durability and usability. MOF composites prepared on readily available textile fibers offer the flexibility essential for critical applications, including heterogeneous catalysis, chemical sensing, toxic gas adsorption, and drug delivery, while preserving the unique characteristics of MOFs. This study introduces a scalable and adaptable method for seamlessly embedding multiple high-performing MOFs onto a single textile fiber using a dip-coating method. We explored the uptake capacity of these multi-MOF composites for CO2, NH3, and SO2 and observed a performance similar to that of traditional powdered materials. Along with harmful gas adsorption, we also have evaluated the permeation and reactivity of these MOF/textile composites toward chemical warfare agents (CWAs) like GD (soman), HD (mustard gas), and VX. In combination, these results demonstrate a fundamental advancement toward establishing a consistent strategy for the hydrolysis of nerve agents in real-world scenarios. This approach can substantially increase the protection toward CWAs and enhance the effectiveness of protective equipment such as fabrics for protective garments. This dip-coating method for the integration of multiple MOFs on a single textile fiber unlocks a wealth of possibilities and paves the way for future innovations in the deployment of MOF-based composites.

An ultrasound assisted dispersive micro solid-phase extraction and a composite ionic liquid-metal organic framework for sixteen polycyclic aromatic hydrocarbons analysis in fruit juice and environmental water samples

Aluminum-based metal organic framework composite containing ionic liquid was prepared and used as sorbent for extraction of sixteen polycyclic aromatic hydrocarbons in list of priority pollutants of United States Environmental Protection Agency before their analysis by gas chromatography/mass spectrometry. The dispersive micro solid-phase extraction method, known as a simple and fast method, was preferred as the extraction method. The optimized parameter conditions were 5 mL of sample solution, 10 min sonication by ultrasonic bath, 30 mg of sorbent, 30 °C extraction temperature, 0.1 mL of hexane as elution solvent with 5 min elution time. The suggested method presented that limit of detection and limit of quantification were in the range of 0.01–0.10 μg l-1, and 0.04–0.33 μg L-1, respectively. The intra-day and inter-day repeatability were within the ranges of 1.18–4.88 % and 1.02–5.06 %, respectively. The recoveries for polycyclic aromatic hydrocarbons in peach juice, cherry juice, tap water and rain water samples were obtained in the range of 84.9–99.9 % for spiked 5, 50 and 100 μg l-1 standard polycyclic aromatic hydrocarbons solution.

Metal-Organic Framework-Based Materials for Heavy Metal Sensing in Aqueous Media

Industrial development leads to an increasing amount of pollutants including heavy metal ions in surface and subsurface waters. For instance, wastewater from battery manufacturing, paint manufacturing or metal plating, contain heavy metals in high concentrations. The heavy metals are typically non-biodegradable and not-easy to excrete. Their presence within the organisms causes damage and failure of different organs. Consequently, the permissible concentrations of heavy metal ions in drinking water set by the World Health Organization are on a ppb level.In this work, electrode materials based on metal-organic frameworks (MOFs) are prepared and studied for sensing of heavy metals in aqueous media. These involved MOFs in their pristine form, composites of pristine MOFs and conducting polymer polyaniline as well as their carbonized derivatives. Cadmium and lead ions were used as model pollutants. Thorough physico-chemical characterization of the prepared materials was done using scanning electron microscopy, Raman spectroscopy, and dynamic light scattering. Electroanalytical performance was scrutinized using anodic stripping voltammetry and correlated with materials’ structural, morphology and textural properties. Limits of detection and sensitivity were determined upon optimization of the experimental conditions to identify the best material. Moreover, materials proved to be suitable for two heavy metal ions sensing in real river samples. Acknowledgments This work was supported by the Science Fund of the Republic of Serbia, grant number 7750219, Advanced Conducting Polymer-Based Materials for Electrochemical Energy Conversion and Storage, Sensors and Environmental Protection-AdConPolyMat (IDEAS programme).

Crystalline Metal-Organic Framework Coatings Engineered via Metal-Phenolic Network Interfaces.

Crystalline metal-organic frameworks (MOFs) have garnered extensive attention owing to their highly ordered porous structure and physicochemical properties. However, their practical application often requires their integration with various substrates, which is challenging because of their weakly adhesive nature and the diversity of substrates that exhibit different properties. Herein, we report the use of amorphous metal-phenolic network coatings to facilitate the growth of crystalline MOF coatings on various particle and planar substrates. Crystalline MOFs with different metal ions and morphologies were successfully deposited on substrates (13 types) of varying sizes, shapes, and surface chemistries. Furthermore, the physicochemical properties of the coated crystalline MOFs (e.g., composition, thickness) could be tuned using different synthesis conditions. The engineered MOF-coated membranes demonstrated excellent liquid and gas separation performance, exhibiting a high H2 permeance of 63200 GPU and a H2/CH4 selectivity of 10.19, likely attributable to the thin nature of the coating (~180 nm). Considering the vast array of MOFs available (>90,000) and the diversity of substrates, this work is expected to pave the way for creating a wide range of MOF composites and coatings with potential applications in diverse fields.

Crystalline Metal–Organic Framework Coatings Engineered via Metal–Phenolic Network Interfaces

AbstractCrystalline metal–organic frameworks (MOFs) have garnered extensive attention owing to their highly ordered porous structure and physicochemical properties. However, their practical application often requires their integration with various substrates, which is challenging because of their weakly adhesive nature and the diversity of substrates that exhibit different properties. Herein, we report the use of amorphous metal–phenolic network coatings to facilitate the growth of crystalline MOF coatings on various particle and planar substrates. Crystalline MOFs with different metal ions and morphologies were successfully deposited on substrates (13 types) of varying sizes, shapes, and surface chemistries. Furthermore, the physicochemical properties of the coated crystalline MOFs (e.g., composition, thickness) could be tuned using different synthesis conditions. The engineered MOF‐coated membranes demonstrated excellent liquid and gas separation performance, exhibiting a high H2 permeance of 63200 GPU and a H2/CH4 selectivity of 10.19, likely attributable to the thin nature of the coating (~180 nm). Considering the vast array of MOFs available (>90,000) and the diversity of substrates, this work is expected to pave the way for creating a wide range of MOF composites and coatings with potential applications in diverse fields.

Advancing Anode Performance in Aqueous Zinc-Ion Batteries: A Review of Metal-Organic Framework-Based Strategies.

Aqueous zinc-ion batteries (AZIBs) are garnering substantial research interest in electric vehicles, energy storage systems, and portable electronics, primarily for the reason that the inexpensive cost, high theoretical specific capacity, and environmental sustainability of zinc metal anodes, which are an essential component to their design. Nonetheless, the progress of AZIBs is hindered by significant obstacles, such as the occurrence of anodic side reactions (SR) and the formation of zinc dendrites. Metal-organic framework (MOF)-based materials are being explored as promising alternatives owing to homogeneous porous structure and large specific surface areas. There has been a rare overview and discussion on strategies for protecting anodes using MOF-based materials. This review specifically aims to investigate cutting-edge strategies for the design of highly stable MOF-based anodes in AZIBs. Firstly, the mechanisms of dendrites and SR are summarized. Secondly, the recent advances in MOF-based anodic protection including those of pristine MOFs, MOF composites, and MOF derivatives are reviewed. Furthermore, the strategies involving MOF-based materials for zinc anode stabilization are presented, including the engineering of surface coatings, three-dimensional zinc structures, artificial solid electrolyte interfaces, separators, and electrolytes. Finally, the ongoing challenges and prospective directions for further enhancement of MOF-based anodic protection technologies in AZIBs are highlighted.

Interconversion and functional composites of metal-organic frameworks and hydrogen-bonded organic frameworks.

Metal-organic frameworks (MOFs), an emerging class of highly ordered crystalline porous materials, possess structural tunability, high specific surface area, well-defined pores, and diverse pore environments and morphologies, making them suitable for various potential applications. Moreover, hydrogen-bonded organic frameworks (HOFs), constructed from organic molecules with complementary hydrogen-bonding patterns, are rapidly evolving into a novel category of porous materials due to their facile mild preparation conditions, solution processability, easy regeneration capability, and excellent biocompatibility. These distinctive advantages have garnered significant attention across diverse fields. Considering the inherent binding affinity between MOFs and HOFs along with the fact that many MOF linkers can serve as building blocks for constructing HOFs, their combination holds promise in creating functional materials with enhanced performance. This feature paper provides an introduction to the interconversion between MOFs and HOFs followed by highlighting the emerging applications of MOF-HOF composites. Finally, we briefly discuss the current challenges associated with future perspectives on MOF-HOF composites.

Binary metal–organic framework composites as environmentally friendly photocatalysts: Green synthesis and visible light-assisted pollutant degradation

Green synthesis of MOF-on-MOF is an effective method to prepare the environmentally friendly photocatalyst using metal–organic frameworks (MOFs). Herein, ZIF-8 was synthesized on MIL-100 (Fe) (ZM composites) with different weight percent ratios of ZIF-8 and denoted as ZM21, ZM11 and ZM12. They were investigated as environmentally friendly photocatalysts for the degradation of Methylene Blue (MB) using visible light. XRD, FT-IR, SEM, EDX, and DRS were used to characterize the synthesized materials (ZIF-8, MIL-100, ZM21, ZM11, and ZM12). The ZM11 composite had the highest dye degradation ability. The MB photocatalytic degradation for the ZIF-8, MIL-100, ZM21, ZM11, and ZM12 were 12.59%, 31.27%, 29.45%, 86.3, and 31.51%, respectively. MB degradation by ZM11 composite followed the first-order kinetic model. The effective radical for the MB photocatalytic degradation was the superoxide radical (•O2–). The ZM11 composite had the ability of 76% dye removal from water after 3 cycles of MB degradation.

Synthesis, characterization and sensing applications of TiO2 doped MOF composites for selective detection of ammonia at room temperature

Herein, we have developed a highly sensitive chemiresistive TiO2 doped metal–organic framework(MOF) composite-based sensor for ammonia detection at room temperature. Two novel Ti-MOFs@TiO2 composites are developed employing terephthalic acid and 2-amino terephthalic acid as organic linkers with Titanium tetra isopropoxide (TTIP) as a metal source by solvothermal technique. The morphology and crystallinity of synthesized compounds were characterized by using Field-emission scanning electron microscopy (FE-SEM) with EDX analysis, X-ray diffraction (PXRD), XPS and Brunauer–Emmett–Teller (BET) analysis techniques. MIL-125@TiO2 sensors exhibited a more specific surface area (374.74 m2 g−1) than the other three compounds. For gas-sensing applications, all composite materials were exposed to different gas vapours like ammonia, formaldehyde, acetic acid, ethyl alcohol, acetone, xylene, toluene and benzene at room temperature. The sensing results indicate that the sensors exhibit excellent response at low concentrations of ammonia, formaldehyde and acetic acid gases (1 ppm level). The enhanced sensor response was attributed to MIL-125@TiO2 (85 response at 50 ppm) and NH2-MIL-125@TiO2 (71 response at 50 ppm) towards ammonia gas and shows a better selectivity, sensitivity and repeatability to ammonia gas. All the materials exhibited less response times (between 8 and 45 sec) and more recovery times (between 13 and 125 sec).

Enhanced Ni(II) Removal from Wastewater Using Novel Molecular Sieve-Based Composites.

This study focuses on the efficient removal of Ni(II) from spent lithium-ion batteries (LIBs) to support environmental conservation and sustainable resource management. A composite material, known as molecular sieve (MS)-based metal-organic framework (MOF) composites (MMCs), consisting of a synthesized MS matrix with integrated MOFs, was developed for the adsorption of Ni(II). The structural and performance characteristics of the MMCs were evaluated using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and N2 adsorption-desorption isotherms (BET). Batch adsorption experiments were conducted to assess the Ni(II) adsorption performance of the MMCs. The results revealed that, under conditions of pH 8 and a temperature of 298 K, the MMCs achieved near-equilibrium Ni(II) adsorption within 6 h, with a maximum theoretical adsorption capacity of 204.1 mg/g. Further analysis of the adsorption data confirmed that the adsorption process followed a pseudo-second-order kinetic model and Langmuir isotherm model, indicating a spontaneous, endothermic chemical adsorption mechanism. Importantly, the MMCs exhibited superior Ni(II) adsorption compared to the MS. This study provides valuable insights into the effective recovery and recycling of Ni(II) from spent LIBs, emphasizing its significance for environmental sustainability and resource circularity.

Advanced supercapacitor electrodes: Synthesis and electrochemical characterization of graphene oxide-bismuth metal-organic framework composites for superior performance

The primary requirements for a viable supercapacitor electrode material are increased energy density, high specific capacitance, and excellent cycle stability. The desired outcome may be attained by combining diverse active materials. In this research, two Bi-MOFs with 1,4-benzenetdicarboxylic (H2BDC) and 1,3,5-benzenetricarboxylic (H3BTC) organic linkers were synthesized by facile solvothermal method and bonded on the surface of graphene oxide to produce FGO-Bi(BTC) and FGO-Bi(BDC) composites. The electrochemical characteristics of the two electroactive compounds were evaluated by GCD, CV, and EIS tests in a three-electrode setup. Comparative electrochemical analyses demonstrated that the composites exhibit remarkable performance with reduced charge transfer resistance. In the three-electrode configuration, FGO-Bi(BDC) and FGO-Bi(BTC) exhibited specific capacitances of 559 and 422 F g-1 at 1 A g-1, respectively. After conducting 10,000 cycles of charge and discharge at 8 A g-1, the FGO-Bi(BDC) and FGO-Bi(BTC) electrodes exhibited impressive retention rates of 97.6% and 95.64% for their initial specific capacitance (Cs). Notably, the three-electrode system's results indicated superior electrochemical performance of the FGO-Bi(BDC) electrode over the FGO-Bi(BTC) electrode. This superiority is attributed to the FGO-Bi(BDC)'s larger specific surface area (SSA) and reduced oxygen concentration. For a more practical assessment, the FGO-Bi(BDC) composite was selected for evaluation in the two-electrode system. The FGO-Bi(BDC)//FGO-Bi(BDC) two-electrode system demonstrated a cyclic stability of 94.2% over 10,000 cycles, attaining a substantial Cs of 295 F g-1 at 1 A g-1. Moreover, it accomplished a power density of 750 W kg-1 and an energy density of 34.61 Wh kg-1, emphasizing the exceptional electrochemical attributes that position the FGO-Bi(BDC) composite as a promising electrode material for supercapacitors.

Nano ZIF-67/PBA derived core-shell sulfides or phosphides for enhanced electrochemical performance of supercapacitors

Metal-organic frameworks (MOFs) possess large specific surface area, high porosity, and adjustable pore size, exhibiting a broad prospect in the field of supercapacitors. However, the poor stability and conductivity of MOFs limited their application in energy storage. The structure of MOF composites and their derivatives are beneficial for storing electric charge and boosting the diffusion of electrolyte ions. In this study, we prepared heterostructured ZIF-67/Prussian blue analogues (PBA) derived sulfides and phosphides using the hydrothermal and solid-phase phosphating method, respectively. The ZIF-67/PBA composites with an average particle size of approximately 1100 nm, retained the rhombic dodecahedral shape of ZIF-67. Compared with MOF-derived phosphides, MOF-derived sulfides more completely retained the rhombic dodecahedron morphology of ZIF-67/PBA and demonstrated good electrochemical performance, especially ZPS-3. The unique core-shell nanostructure provides more active sites and suitable ion transport paths for reversible oxidation-reduction reactions. In three-electrode system, the ZPS-3 electrode exhibited a specific capacity of 603.9 F g−1 at a current density of 0.5 A g−1, superior rate performance, and excellent cycle stability. This study established a new synthesis paradigm for the development of MOF derivatives as a potential class of electrode materials for supercapacitors.

Central Metal-Triggered Structural Transformation of a 2D Layered MOF: Mechanistic Studies and Applications.

The structural transformation of metal-organic frameworks (MOFs) has attracted increasing interests, which has not only produced various new structures but also served as a fantastic platform for MOF-based kinetic analysis. Multiple reaction conditions have been documented to cause structural transformation; nevertheless, central metal-induced topological alteration of MOFs is rare. Herein, we reported a structural transformation of a 2D layered Cd-MOF driven by Cd(II) ions. After being submerged in the aqueous solution of cadmium nitrate, the twofold interpenetrated 2D network of [Cd(hsb-2)(bdc)·5H2O]n [HSB-W10; bdc: 1,4-benzenedicarboxylate; hsb-2:1,2-bis(4'-pyridylmethylamino)-ethane] was converted into a novel noninterpenetrated 2D network [Cd1.5(hsb-2)(bdc)1.5(H2O)2·H2O]n (HSB-W16). This partial dissolution-recrystallization process was investigated by integrating controlled experiments, 1H NMR spectra, and photographic tracking analysis. Furthermore, a novel strategy combining in situ multicomponent dye encapsulation and central metal-triggered structural transformation was developed for the fabrication of MOF materials with white-light emission. By adopting this strategy, different dye guest molecules were concurrently introduced into the HSB-W16 host matrix, leading to a range of white-light-emitting MOF composites. This work will enable detailed studies of solid-state transformations and demonstrate a promising application prospect for structural transformation.

Probing the capability of the MOF-74(Ni)@GrO composite for CO2 adsorption and CO2/N2 separation: A combination of experimental and molecular dynamic simulation studies

Given the significant impact of carbon dioxide emissions on current and future human life, the imperative for CO2 reduction becomes evident. Metal-organic frameworks (MOFs) composites stand out as highly effective adsorbents for CO2 capture and separation. In this study, MOF-74(Ni)@graphene oxide (GrO) composites were successfully generated through a hydrothermal synthesis route. The thermal, pore, and textural properties of the new MOF composites were experimentally tested through TGA, N2 adsorption–desorption, XRD, and FTIR. The adsorption and separation characteristics of the new MOF composites were evaluated through experimental and molecular dynamic (MD) simulation studies at ambient conditions. Interestingly, the BET surface area of all composites significantly increased compared to the pristine MOF. Among all composites, MOF-74(Ni)@GrO-10 demonstrated the highest value, surpassing others by 1060 cm2/g. MOF-74(Ni)@GrO-10 composite demonstrates the maximum amount of CO2 uptake capacity of 5.76 mmol/g experimentally and 6.65 mmol/g numerically, evidencing a substantial enhancement of 25 % and 28 % in comparison to the pristine MOF-74(Ni). The determination of CO2/N2 selectivity for all samples was carried out through a single-component isotherm under post-combustion conditions (PCO2/PN2: 0.15 bar/ 0.75 bar). Concerning CO2/N2 selectivity, the MOF-74(Ni)@GrO-10 composite also displayed the highest selective adsorption values of 44 and 45 experimentally and numerically, respectively. This marks a significant 7 % enhancement compared with the bare MOF. MOF-74(Ni)@GrO-10 exhibited a significantly higher heat of CO2 adsorption compared to bare MOF-74.As evidenced by both experimental and numerical results, MOF-74(Ni)@GrO-10 indicated 37 kJ/mol and 39 kJ/mol, and MOF-74(Ni) showed 34.5 kJ/mol and 36.5 kJ/mol heat of CO2 adsorption, implying that CO2 molecules have a stronger interaction with the composite adsorbent than the bare MOF. MOF-74(Ni)@GrO-10 also exhibited high stability, preserving 95 % of its structure after five consecutive adsorption–desorption cycles in both studies. The research finding implies that MOF-74(Ni)@GrO-10 is a promising adsorbent that can be widely used in adsorption and separation technology.

Ethylene Polymerization over Metal-Organic Framework-Supported Zirconocene Complexes.

Metallocene immobilization onto a solid support helps to overcome the drawbacks of homogeneous metallocene complexes in the catalytic olefin polymerization. In this study, valuable insights have been obtained into the effects of pore size, linker composition, and surface groups of metal-organic frameworks (MOFs) on their role as support materials for metallocene-based ethylene polymerization catalysis. Three distinct Zn-based metal-organic frameworks (MOFs), namely, MOF-5, IRMOF-3, and ZIF-8, with different linkers have been activated with methylaluminoxane (MAO) and zirconocene complexes, followed by materials characterization and testing for ethylene polymerization. Characterization has been performed by multiple analytical tools, including X-ray diffraction (XRD), scanning electron microscopy (SEM), gel permeation chromatography (GPC), differential scanning calorimetry (DSC), and CO Fourier transform infrared (FT-IR) spectroscopy. It was found that the interactions between MOFs, MAO, and the zirconocene complex not only lead to both catalyst activation and deactivation but also result in the creation of multiple active sites. By alteration of the MOF support, it is possible to obtain polyethylene with different properties. Notably, ultrahigh molecular weight polyethylene (UHMWPE, M W = 5.34 × 106) was obtained using IRMOF-3 as support. This study reveals the potential of MOF materials as tunable porous supports for metallocene catalysts active in ethylene polymerization.

A novel solid-phase extraction device for the pneumatic cycle pharmaceuticals residues adsorption: A proof of concept study

In this study, a pneumatic cycle device, herein called the air-operated solid-phase extraction (AO-SPE), was designed for the enrichment of pharmaceutical residues. The device consisted of two parts: an air circulation system and an adsorption system. The continuous air flow ensured that the water sample flowed past the adsorbent, completing the adsorption process. One significant advantage of this device is that the air circulation system can generate pneumatic cycle adsorption with the continuous air flow, increasing the interaction between the adsorbent and the target analytes. Additionally, the entire device is easy to install and dismantle, and the adsorbent can be easily replaced, making the AO-SPE suitable for various types of adsorbents materials tailored to specific target analytes. The smart design is aimed at extracting trace analytes in the large-volume water samples. As a proof-of-concept, the AO-SPE was applied to enrich non-steroidal anti-inflammatory drugs in soil. A Ce-based metal organic framework composite was prepared and applied to verify the applicability of AO-SPE, exhibiting the enrichment factor of up to 538. The results showed that AO-SPE exhibited a maneuverable approach with high efficiency and sensitivity for analyzing large-volume samples, indicating a great potential for extracting of trace analytes.

Recent Advances in Metal-Organic Framework (MOF)-Based Composites for Organic Effluent Remediation.

Environmental pollution caused by organic effluents emitted by industry has become a worldwide issue and poses a serious threat to the public and the ecosystem. Metal-organic frameworks (MOFs), comprising metal-containing clusters and organic bridging ligands, are porous and crystalline materials, possessing fascinating shape and size-dependent properties such as high surface area, abundant active sites, well-defined crystal morphologies, and huge potential for surface functionalization. To date, numerous well designated MOFs have emerged as critical functional materials to solve the growing challenges associated with water environmental issues. Here we present the recent progress of MOF-based materials and their applications in the treatment of organic effluents. Firstly, several traditional and emerging synthesis strategies for MOF composites are introduced. Then, the structural and functional regulations of MOF composites are presented and analyzed. Finally, typical applications of MOF-based materials in treating organic effluents, including chemical, pharmaceutical, textile, and agricultural wastewaters are summarized. Overall, this review is anticipated to tailor design and regulation of MOF-based functional materials for boosting the performance of organic effluent remediation.

Enhanced Antimicrobial Activity of Laser‐induced Graphene Wrapped Tri‐Metal Organic Framework Nanocomposites

Crystalline and porous metal‐organic frameworks (MOFs) are potential candidates for different antibacterial, photocatalytic, and adsorption applications. Moreover, multi‐principal element nanoparticles are effective against multidrug‐resistant bacteria, and combining metals with carbon nanomaterials can enhance activity. In this study, a Tri‐MOF comprised of iron, zinc, and cobalt and 2‐methyl imidazole was grown together with laser‐induced graphene (LIG) powder. Electron microscopy imaging showed the successful preparation and the crystalline nature of the LIG/Tri‐MOF composite. Fourier‐transform infrared and X‐ray photoelectron spectroscopy confirmed a non‐covalent mixture of LIG and Tri‐MOF. Compared with the negligible activity of LIG alone, low doses (0.91‐4.54 mg/mL) of the prepared LIG/Tri‐MOF composite showed excellent antibacterial activity (≥ 95% bacterial removal) and a MIC of 0.6 mg/mL, for Gram‐negative bacteria via the gradual leaching of metal ions and organic linker from the material enhanced by bacterial aggregation near the LIG/Tri‐MOF. Compared to a mixture of separately synthesized Tri‐MOF and LIG, the LIG/Tri‐MOF composite showed improved antibacterial effects. All materials showed cytotoxicity for L929 mouse cell lines, the solids showing a disrupting effect on cells grown in vitro. Performance‐enhancing combinations of various materials leading to synergistic or additive antimicrobial effects is an essential strategy for minimizing the possible emergence of antibiotic‐resistant strains.This article is protected by copyright. All rights reserved.

Enzyme_Metal-Organic Framework Composites as Novel Approach for Microplastic Degradation.

Plastic pollution is one of the main worldwide environmental concerns. Our lifestyle involves persistent plastic consumption, aggravating the low efficiency of wastewater treatment plants in its removal. Nano/microplastics are accumulated in living beings, pushing to identify new water remediation strategies to avoid their harmful effects. Enzymes (e. g., Candida rugosa-CrL) are known natural plastic degraders as catalysts in depolymerization reactions. However, their practical use is limited by their stability, recyclability, and economical concerns. Here, enzyme immobilization in metal-organic frameworks (CrL_MOFs) is originally presented as a new plastic degradation approach to achieve a boosted plastic decomposition in aqueous systems while allowing the catalyst cyclability. Bis-(hydroxyethyl)terephthalate (BHET) was selected as model substrate for decontamination experiments for being the main polyethylene terephthalate (PET) degradation product. Once in contaminated water, CrL_MOFs can eliminate BHET (37 %, 24 h), following two complementary mechanisms: enzymatic degradation (CrL action) and byproducts adsorption (MOF effect). As a proof-of-concept, the capacity of a selected CrL_MOF composite to eliminate the BHET degradation products and its reusability are also investigated. The potential of these systems is envisioned in terms of improving enzyme cyclability, reducing costs along with feasible co-adsorption of plastic byproducts and other harmful contaminants, to successfully remove them in a single step.