Zeolitic Imidazolate Framework Research Articles

Improving energy storage ability of nickel and cobalt hydroxides coupled with reduced graphene oxide via incorporating novel structure-directing agents for supercapacitors

Zeolitic imidazolate framework 67 (ZIF67) derivatives are regarded as potential active materials for energy storage, owing to the possible enhancement on electrical conductivity and maintenance of high surface area and tunable pore structure. However, current improvements on electrical and physical properties of ZIF67 derivatives are still insufficient to achieve excellent energy storage abilities. In this study, new types of carbon material and structure-directing agents (SDA) are incorporated into the synthesis of ZIF67 derivatives to enhance electrical conductivity and modulate morphology. Commercial reduced graphene oxide (rGO), NH4BF4 and NH4HF2 are applied as the carbon material and SDAs, respectively. With the optimal rGO ratio, the rGO/ZIF67 derivative electrode exhibits a higher specific capacitance (CF) of 1304.7 F/g (913.0C/g) at 20 mV/s, while the ZIF67 derivative electrode without rGO shows a CF value of 786.9 F/g (550.8C/g). The supercapacitor composed of the optimal rGO/ZIF67 derivative and rGO electrodes presents a maximum energy density of 30.2 Wh/kg at 350 W/kg. The Coulombic efficiency of 93.0 % and CF retention of 86.5 % are achieved for the device after 10,000 cycles. The novel carbon material and SDAs are expected to be applicable in more electrochemical systems to achieve better energy storage ability.

Construction of a N-CDs/AuNCs@ZIF-8-assisted ratiometric fluorescent nanosensor for glyphosate detection in edible and medicinal malt

Glyphosate (Gly) is a widely-used herbicide in food production, while, the residue of which due to the long-term and excessive overspray poses serious threats to public health. The development of reliable methods for its sensitive detection is of great urgency. In this study, a novel ratiometric fluorescent nanosensor by encapsulating N-doped carbon dots (N-CDs) and gold nanoclusters (AuNCs) in zeolitic imidazole framework-8 (ZIF-8) as the dual-emissive fluorescence probes at 410 and 650 nm, respectively, was constructed for Gly detection. Due to the adsorption property of ZIF-8, the N-CDs/AuNCs@ZIF-8 nanoprobes accumulated Cu2+ to quench the red fluorescence of AuNCs, and the blue fluorescence of N-CDs was stable. While thiocholine, a product of acetylthiocholine, hydrolyzed by acetylcholinesterase could coordinate with Cu2+, resulting in significant fluorescence recovery of AuNCs. This phenomenon was utilized for the quantitation of Gly, due to its inhibitory effect on acetylcholinesterase activity. By calculating the fluorescence intensity ratio (I650/I410), Gly in real sample could be accurately determined in a concentration range of 2–100 ng/mL with a limit of detection of 1.92 ng/mL because of the anti-interference and the self-correction ability of the two fluorescence signals. The N-CDs/AuNCs@ZIF-8 nanoprobes-assisted ratiometric fluorescent nanosensor exhibited unique merits of rapid construction, simple operation, high specificity, and good accuracy for Gly in edible and medicinal malt samples with recoveries of 93.7–108.2 %. This study presents a multiple tool for the versatile sensing of trace pesticides in more food matrices, which can be extended to a full range of environmental and food safety applications.

Metal organic framework derived composite as a new sorbent for micro-solid phase extraction of parabens from breast milk samples

In an attempt to enhance the adsorptive properties while addressing the limitations associated with powdered nature, zeolitic imidazolate framework (ZIF-67)-derived cobalt-doped nanoporous carbon (Co-NPC) was incorporated into chitosan and then shaped like hollow fiber by a simple casting method. Further modification with polyaniline (PANI) was also performed to improve extraction efficacy. The applicability of the modified hollow fibers was then investigated by packing them into a cartridge and utilizing them for conducting hollow fibers-packed in-cartridge micro solid-phase extraction (HF-IC µ-SPE) of parabens including methylparaben (MP), ethylparaben (EP), and propylparaben (PP) from human breast milk samples. Factors affecting extraction performance were studied using central composite design (CCD). Under the optimal conditions, good linearity was achieved within the range of 0.5-500 μg L−1 with the determination coefficient (R2) higher than 0.9901. All analytical parameters were obtained by liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. In this regard, the limits of detection values (LODs) were 0.5 to 1.0 μg L−1. Intra- and inter-assay precision RSDs % were lower than 7.9% and 8.4%, respectively. Relative recoveries of breast milk samples were found in the range of 88.0-109.5%. Accordingly, the novel nanocomposite sorbent based on PANI@Co-NPC/Chitosan hollow fiber was found to be an efficient, simple, and cost-effective packing material for HF-IC µ-SPE. It can also be offered as a promising alternative adsorbent to coated conventional hollow fiber.

Synergistic effects of gadolinium oxide into the matrix of zeolitic imidazolate frameworks (ZIFs) for supercapacitor applications

In this study, we synthesized ZIF-8, ZIF-67, Gd₀.₀₁/ZIF-8, & Gd₀.₀₁/ZIF-67 electrodes using the direct combination technique. Both electrodes are being used for energy storage devices. We extensively evaluated these nanocomposites using a variety of electrochemical methods, including retention analysis, galvanostatic charge-discharge (GCD), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). ZIF-8 exhibits a wide band gap of approximately 2.58 eV, suggesting its main absorption is of UV light. The peaks in the absorbance spectrum vary slightly in wavelength due to the presence of different metal centers. Peaks between 1400-1600 cm⁻1 indicate C–N stretching vibrations from the imidazolate linkers. Peaks between 1600-1700 cm⁻1 are associated with C=C stretching vibrations. ZIF-8 exhibits well-defined peaks in its XRD pattern, indicating a high level of crystallinity. Peaks can be observed at specific 2θ values, typically at 22.09°, 26.62°, 38.49°, and 47.27°, which correspond to the (110), (200), (211), and (220) planes. The calculated specific capacitances for ZIF-8 and ZIF-67 are 223.95 and 255.20 F/g. For Gd0.01/ZIF-8, & Gd0.01/ZIF-67 specific capacitances are 575.00 and 587.50 F/g. The ZIF-8, ZIF-67, Gd0.01/ZIF-8, & Gd0.01/ZIF-67 electrodes exhibited specific capacitances of (78.30, 192.59, 342.57, and 1164) F/g at current densities of 1 A/g from the GCD calculation. The retention plot of ZIF-8, ZIF-67, Gd0.01/ZIF-8, & Gd0.01/ZIF-67 electrode shows efficiency of 71%, 71%, 105% and 75%, respectively, indicating their suitability for supercapacitor applications.

An electrostatically spun cellulose-based self-powered mask with high efficiency air filtration and ammonia sensing

On construction sites impacted by particulate matter and hazardous gases, portable integrated air filtration equipment with high efficiency, minimal pressure drops and ammonia (NH3) alarms is critical. Triboelectric nanogenerators (TENG) present a sustainable solution by generating self-powered electricity to fulfill these requirements. In this study, we synthesized zeolitic imidazolate framework-8 (ZIF-8) in situ on the surface of titanium carbide (Ti3C2Tx) to create Ti3C2Tx/ZIF-8, grafted it onto cellulose diacetate via tetraethyl orthosilicate, and ultimately developed a cellulose-based nanofibrous membrane through electrospinning, combining it with a negative triboelectric material to construct a self-powered TENG-based mask. The device achieved a balance between a low pressure drop (61 Pa) and high filtration efficiency (99.21 %, 99.71 %, and 99.98 % for PM0.3, PM0.5, and PM1, respectively). Furthermore, the device responds swiftly to NH3; at a concentration of 100 ppm NH3, it achieves a rapid response rate of 83 %, with a response/recovery time as low as 12/14 s. Notably, the device retains its rapid sterilization capability within a short duration (20 min) and demonstrates remarkable stability across its various performance metrics, even after multiple washes. This study presents a novel approach to the development of multi-use, self-powered wearable devices featuring excellent air filtration performance and NH3 detection capabilities.

A novel CoCuNi-sulfide nanocatalyst derived from trimetallic zeolitic imidazolate framework for boosting oxygen evolution reaction performance: comparison study of sulfides and oxides

The investigation of multi-component transition metals has been undertaken as a means to enhance the oxygen evolution reaction (OER) performance contrasted with single-component transition metals. In this study, we prepare a series of monometallic (ZIF-67), bimetallic (ZIF-CoCu), and novel trimetallic zeolitic imidazolate frameworks (ZIF-CoCuNi) via a facile one-step room-temperature solution precipitation method. The optimized CoCuNi-sulfide nanoparticles with amorphous structure and rough surface exhibit superior catalytic activity for OER in 1 mol L-1 KOH with a low overpotential of 210 mV at a current density of 10 mA.cm−2 and negligible reduction in operational capabilities following a stability test lasting 24 hours. This study showcases that both the sulfidation process and the synergy of multiple components yield favorable outcomes in terms of enhancing the activity and stability of OER. These findings present a new approach to fabricating and developing high-efficiency and low-cost electrocatalysts, which have an essential part in the conversion of energy.

Enhancing CO2 adsorption with modified zeolite imidazolate frameworks (ZIF-8) functionalized with amine groups

Enhancing CO2 adsorption with modified zeolite imidazolate frameworks (ZIF-8) functionalized with amine groups

Designing Artificial Laccase Catalysts by Introducing Substrate Oxidation Metals into Oxygen-Reducing Metal-Organic Frameworks: Cu-Doped ZIF-67.

Laccase, a multi-copper oxidase, is limited by its optimal temperature range and isolation costs. To overcome these challenges, we synthesized copper-doped zeolitic imidazolate framework-67 (Cu-doped ZIF-67) with 16 mol % Cu as an artificial laccase catalyst. The introduced Cu site acts as the phenol oxidation site, and Co-based ZIF-67 is the four-electron oxygen reduction site. Laccase also employs this division of oxidation and reduction sites. Cu-doped ZIF-67 demonstrated significant catalytic activity, superior to natural laccase, especially at elevated temperatures, and maintained stability across multiple reaction cycles. These findings suggest that Cu-doped ZIF-67 is a robust, reusable alternative for industrial applications requiring high thermal stability and efficient catalysis.

Nanobiohybrid Extracellular Vesicle Nanoreactor with Improving Metabolical Activity for Biocatalytic Therapy.

Extracellular vesicles (EVs) hosting enzymatic activities that function as independent metabolic units are attractive natural biocatalytic platforms. However, directly using these metabolically active nanoreactors for effective biocatalytic applications remains challenging, mainly due to their constrained catalytic capabilities. Here, we construct an EV-templated nanobiohybrid system by engineering an EV surface with a photoresponsive zeolitic imidazolate framework (ZIF). The deposition of ZIF nanostructures on EVs not only contributes to improved biocatalytic stability but also enables interfacial coupling between photoexcited electrons from the ZIF and the enzymatic reaction of metabolically active EVs. Nearly 300% of biomass conversion efficiency increment could be achieved by EVs derived from macrophages. This enhanced biocatalysis, high catalytic stability, and low cytotoxicity endowed the EV@ZIF nanosystem with robust biosynthesis and antimicrobial activity. When evaluated in a mouse periodontitis model, we show that the autologous biocatalytic EV@ZIF demonstrated efficient therapeutic capability by killing bacteria and inhibiting inflammation. This nanoengineering strategy will benefit the future optimization of metabolically active EV nanoreactors as biocatalysts for a broad range of therapeutics.

Atomically Tailored Zn-ZIF-8 via RuNi Nanoalloy Replacement for Improved Photocatalytic H2 Evolution.

In this study, we developed a solid-state atomic replacement method for metal catalysts, enabling the exchange of metal atoms between single atoms and nanoalloys to create new combinations of nanoalloys and single atoms. We observed that partial metal interchange occurred between the RuNi nanoalloy and Zn from the zeolitic imidazolate framework-8 (ZIF-8) on a carbon-nitrogen framework (CNF) at a high temperature of 900 °C, leading to the creation of RuZn nanoparticles and single nickel atoms (Ni-CN). Extended X-ray absorption fine structure (EXAFS) and X-ray absorption near edge structure (XANES) analyses revealed that Ni is atomically dispersed within (RuZn)/Ni-CN. This finding confirms the migration of Zn and Ni during the pyrolysis of the RuNi@ZIF-8 precursor, providing definitive evidence of atomic replacement. Due to the synergistic influence of RuZn nanocrystals and Ni-CN, the resulting (RuZn)/Ni-CN multisite catalyst exhibited superior hydrogen evolution reaction (HER) ability compared to the conventional nanoalloy-based catalysts. Density functional theory calculations revealed that the integration of the (RuZn)n cluster on Ni surrounded with different N-coordinated carbon structures enhanced HER activity with the optimized (RuZn)n/NiN2C2 catalyst exhibiting a low ΔGH and improved electron charge redistribution, thereby promoting favorable hydrogen adsorption. Our findings provide valuable insights into the design and optimization of photocatalysts through atomic-level engineering, opening new avenues for efficient and sustainable energy conversion technologies.

PH-Responsive Metal–Organic Framework for Targeted Delivery of Fungicide, Release Behavior, and Sustainable Plant Protection

A smart and environmentally friendly pesticide system was developed that could respond to environmental stimuli while mitigating environmental risks. In this study, thiabendazole (Thi), an effective fungicide, was loaded onto zeolitic imidazolate framework-8 (ZIF-8) using the impregnation method to fabricate a pH-responsive nano hybrid delivery system (Thi@ZIF-8). The results demonstrated that Thi@ZIF-8 had a rhombic dodecahedral morphology and a loading capacity of approximately 25%. Notably, the amount of Thi released from Thi@ZIF-8 at a pH of 5.0 reached 79.54%, which was higher than that at pH 7.0 and 9.0, for 251 h. Such pH-responsive release characteristics of Thi@ZIF-8 were probably related to the pH-dependent structure stability of ZIF-8. The release mechanism of Thi@ZIF-8 conformed to non-Fickian diffusion. Additionally, Thi@ZIF-8 showed a higher control efficacy against B. cinerea compared with Thi alone. Importantly, the ZIF-8 carrier could effectively reduce the leaching loss of Thi in soil and showed no negative effects on the three varieties of tomato seedlings, implying good biocompatibility. This work provides a novel and eco-friendly approach to control B. cinerea effectively that has great potential in modern sustainable agriculture.

Modulating Fibrotic Mechanical Microenvironment for Idiopathic Pulmonary Fibrosis Therapy.

Idiopathic pulmonary fibrosis (IPF) is exacerbated by injurious mechanical forces that destabilize the pulmonary mechanical microenvironment homeostasis, leading to alveolar dysfunction and exacerbating disease severity. However, given the inherent mechanosensitivity of fibrotic lungs, where type II alveolar epithelial cells (AEC IIs) are subjected to persistent stretching and overactivated myofibroblasts experience malignant interactions during mechanotransduction, it becomes imperative to develop effective strategies to modulate the pulmonary mechanical microenvironment. Herein, cyclo (RGDfC) peptide-decorated zeolitic imidazolate framework-8 nanoparticles (named ZDFPR NPs) are constructed to target and repair the aberrant mechanical force levels in pathological lungs. Specifically, reduces mechanical tension in AEC IIs by pH-responsive ZDFPR NPs that release zinc ions and 7, 8-dihydroxyflavone to promote alveolar repair and differentiation. Meanwhile, malignant interactions between myofibroblast contractility and extracellular matrix stiffness during mechanotransduction are disrupted by the fasudil inhibition ROCK signaling pathway. The results show that ZDFPR NPs successfully restored pulmonary mechanical homeostasis and terminated the fibrosis process in bleomycin-induced fibrotic mice. This study not only presents a promising strategy for modulating pulmonary mechanical microenvironment but also pioneers a novel avenue for IPF treatment.

FeN4S1 Single-Atom Sites Anchored on Three-Dimensional Porous Carbon for Highly Efficient and Durable Oxygen Electrocatalysis.

Precisely designing asymmetric active centers and exploring their electronic regulation effects to prepare efficient bifunctional single-atom catalysts (SACs) is important for boosting the practical applications of zinc-air batteries (ZABs). Herein, an effective strategy has been developed by introducing an axial S atom to the FeN4 active center, simultaneously assisted by pyrolyzing the graphene oxide (GO) sheathed zeolitic-imidazolate framework-8 (ZIF8) composite and constructing a three-dimensional (3D) porous framework with abundant FeN4S1 moieties. This structure can accelerate the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) kinetics owing to the modulated electronic redistribution and d-band center with a reduced energy barrier. The optimal S-Fe-NC/rGO showcases a lower voltage gap (ΔE) of 0.64 V between both the ORR and OER half-wave potentials at 10 mA cm-2, highlighting the excellent bifunctional activities. The assembled S-Fe-NC/rGO rechargeable liquid ZABs deliver a power density of 154.05 mW·cm-2 and a desirable durability of >900 h. More importantly, the corresponding flexible solid-state ZABs exhibit considerable foldability.

Injectable Photocrosslinked Hydrogel Dressing Encapsulating Quercetin-Loaded Zeolitic Imidazolate Framework-8 for Skin Wound Healing

Background: Wound management is a critical component of clinical practice. Promoting timely healing of wounds is essential for patient recovery. Traditional treatments have limited efficacy due to prolonged healing times, excessive inflammatory responses, and susceptibility to infection. Methods: In this research, we created an injectable hydrogel wound dressing formulated from gelatin methacryloyl (GelMA) that encapsulates quercetin-loaded zeolitic imidazolate framework-8 (Qu@ZIF-8) nanoparticles. Next, its ability to promote skin wound healing was validated through in vitro experiments and animal studies. Results: Research conducted both in vitro and in vivo indicated that this hydrogel dressing effectively mitigates inflammation, inhibits bacterial growth, and promotes angiogenesis and collagen synthesis, thus facilitating a safe and efficient healing process for wounds. Conclusions: This cutting-edge scaffold system provides a novel strategy for wound repair and demonstrates significant potential for clinical applications.

Twinned Metal-Organic Framework Nanoplates for Hydrocarbon Separation Membranes.

Filler morphology control is critical for enhancing the gas separation performance of mixed matrix membranes (MMMs). A vertical transport channel using the crystal twinning phenomenon is designed on the zeolitic imidazolate framework (ZIF) nanoplate. Twinned ZIF-8 (TZIF-8) nanoplate is prepared by controlling the shape of ZIF-L from nanosheet to twinned flake, followed by conversion into the ZIF-8 phase. With the addition of TZIF-8 in 6FDA-DAM polymer, propylene/propane selectivity is dramatically enhanced, showing propylene permeability of 40 Barrer and propylene/propane selectivity of 82. The separation performance surpasses the performance of MMMs reported so far, and the selectivity is comparable to that of polycrystalline ZIF-8 membranes. A transport mechanism study using mathematical models implies that the percolated twin fillers create rapid and selective gas channels for desired molecules and substantial tortuous pathways for undesired molecules.

Engineering pH and Temperature-Triggered Drug Release with Metal-Organic Frameworks and Fatty Acids

This study reports the successful synthesis of core-shell microparticles utilizing coaxial electrospray techniques, with zeolitic imidazolate framework-8 (ZIF-8) encapsulating rhodamine B (RhB) in the core and a phase change material (PCM) shell composed of a eutectic mixture of lauric acid (LA) and stearic acid (SA). ZIF-8 is well-recognized for its pH-responsive degradation and biocompatibility, making it an ideal candidate for targeted drug delivery. The LA-SA PCM mixture, with a melting point near physiological temperature (39 °C), enables temperature-triggered drug release, enhancing therapeutic precision. The structural properties of the microparticles were extensively characterized through scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). Drug release studies revealed a dual-stimuli response, where the release of RhB was significantly influenced by both temperature and pH. Under mildly acidic conditions (pH 4.0) at 40 °C, a rapid and complete release of RhB was observed within 120 h, while at 37 °C, the release rate was notably slower. Specifically, the release at 40 °C was 79% higher than at 37 °C, confirming the temperature sensitivity of the system. Moreover, at physiological pH (7.4), minimal drug release occurred, demonstrating the system’s potential for minimizing premature drug release under neutral conditions. This dual-stimuli approach holds promise for improving therapeutic outcomes in cancer treatment by enabling precise control over drug release in response to both pH and localized hyperthermia, reducing off-target effects and improving patient compliance.

The Throttle Effect in Metal-Organic Frameworks for Distinguishing Water Isotopes.

Metal-organic frameworks (MOFs) have been widely used for separation, but amplifying subtle differences between similar molecules to achieve effective separation remains a great challenge. In this study, we utilize the fluorescent molecule uranine (Ura) to modulate the pores of zeolitic-imidazolate framework 8 (ZIF8), creating an unusual throttle effect. By monitoring fluorescence intensity changes in Ura, the transport diffusion process could be quantified to reveal the diffusion constant of solvents. When we pushed the Ura occupancy to its limit (from 59% to 76% and 98%), the diffusion rate decreases by 2 orders of magnitude. Most importantly, there is a significant dissymmetry between the two-way exchange rates of solvents, and the rates of H2O and D2O became distinguishable. Such unusual throttle effects disappear at low Ura occupancy of 59% and 76%. We believe that the throttle effect with small-molecule loading could provide a universal design principle for MOF-based applications, especially for isotope separation.

Layer-by-Layer Ligands Engineered Gold Nanoclusters on Zeolitic Imidazolate Framework-8 for Efficient Sensing of Lead Ions

Layer-by-Layer Ligands Engineered Gold Nanoclusters on Zeolitic Imidazolate Framework-8 for Efficient Sensing of Lead Ions

Stem Cell Membrane-Camouflaged Biomimetic Nanoparticles Inhibiting Leptin Pathway for Intervertebral Disc Degeneration Therapy.

Leptin, a kind of adipokine, with its receptor in which the long isoform plays a crucial role in signal transduction, has been identified in intervertebral disc (IVD) tissues, especially showing an increased expression in degenerated discs. Initially identified as a metabolic sensor, leptin has recently been found able to regulate inflammation into imbalance, which favors catabolic degradative processes, thus contributing to progressive intervertebral disc degeneration (IDD). Therefore, efficiently inhibiting the leptin pathway may provide a new strategy to treat IDD. In this study, we introduced an innovative drug delivery system (DDS) that employs stem cell membranes (SCM) to encapsulate (Zeolitic imidazolate frameworks-8) ZIF-8 nanoparticles. These nanoparticles are used to transport a plasmid containing shRNA targeting the leptin receptor (LEPR), with the aim of facilitating repair in IDD. The regenerative performances of this DDS in IDD were verified through a combination of the in vitro western blot and immunofluorescence with the in vivo radiologic examination and histological staining. The DDS demonstrated excellent cell adhesion properties and gene transfection efficiency in vitro, along with impressive treatment outcomes in vivo. Both in vitro and in vivo studies revealed that the DDS effectively reduced leptin receptor expression and alleviated the inflammatory environment, thereby promoting regeneration in degenerated IVDs. We propose that the DDS represents a promising novel approach for treating IDD and may also be beneficial for other degenerative diseases linked to leptin pathway dysfunction.

Tailoring-Orientated Deposition of Li2S for Extreme Fast-Charging Lithium-Sulfur Batteries.

Precipitation/dissolution of insulating Li2S has long been recognized as the rate-determining step in lithium-sulfur (Li-S) batteries, which dramatically undermines sulfur utilization at elevated charging rates. Herein, we present an orientated Li2S deposition strategy to achieve extreme fast charging (XFC, ≤15 min) through synergistic control of porosity, electronic conductivity, and anchoring sites of electrode substrate. Via magnesiothermic reduction of a zeolitic imidazolate framework, a nitrogen-doped and hierarchical porous carbon with highly graphitic phase was developed. This design effectively reduces interfacial resistance and ensures efficient sequestration of polysulfides during deposition, leading to (110)-preferred growth of Li2S nanocrystalline between (002)-dominated graphitic layers. Our approach directs an alternative Li2S deposition pathway to the commonly reported lateral growth and 3D thickening growth mode, ameliorating the electrode passivation. Therefore, a Li-S cell capable of charging/discharging at 5C (12 min) while maintaining excellent cycling stability (82% capacity retention) for 1000 cycles is demonstrated. Even under high S loading (8.3 mg cm-2) and low electrolyte/sulfur ratio (3.8 mL mg-1), the sulfur cathode still delivers a high areal capacity of >7 mAh cm-2 for 80 cycles.