Zeolitic Imidazolate Framework Research Articles

Insights into the post-combustion CO2 capture performance of zinc-based zeolitic imidazolate framework (ZIF8)-derived nanocomposites

We report carbon-zinc oxide (C/ZnO) nanocomposites obtained by a simple, scalable, and cost-effective one-step pyrolysis of a zinc-based zeolitic imidazolate framework (ZIF8) for post-combustion carbon dioxide (CO2) capture. The prepared nanocomposites are thoroughly analyzed by different characterization techniques. The CO2 adsorption–desorption studies performed using thermogravimetric analyzer (TGA) reveal remarkable CO2 adsorption capacity (∼10 wt% at 30 °C, 1 bar) and excellent CO2/N2 selectivity. The low-pressure CO2 uptake capacities measured using Brunauer-Emmett-Teller (BET) analyzer corroborate the TGA results. The best sample exhibits an uptake of 3.13 mmol/g at 30 °C, 1 bar. The experimental isotherms obtained using TGA and BET are fitted using suitable kinetic and adsorption models, respectively, to obtain insights into the underlying adsorption mechanisms. The isosteric enthalpy of adsorption calculated from the Virial analysis of the isotherms confirms the physisorption nature. Excellent CO2 uptake values are also observed in simulated flue gas environments. Additionally, the factors influencing the CO2 adsorption in these nanocomposites are identified by correlating the physical characterization results with the CO2 uptake studies. It is inferred that the amorphous carbon in the nanocomposite determines the adsorption capacity and selectivity, whereas the residual ZnO in it controls the adsorption capacity at 0.15 bar and kinetics.

Characterization of zeolitic imidazole framework (ZIF-8) catalyst for potential biodiesel production from waste cooking oil (WCO)

Heteropoly acids (HPAs) catalysts prove effective in waste cooking oil biodiesel production, considering their high density of Brønsted acidic sites, exhibit significant resilience to elevated levels of free fatty acid (FFA) and moisture content. However, the separation of HPA catalysts after biodiesel production is challenging due to their homogeneous catalytic nature. This study aims to develop magnetic vanadium-substituted HPAbased ZIF-8 composites to create a catalyst for biodiesel production from WCO that is more efficient and easier to separate. In this work, a range of analytical methods was utilized to characterize the catalyst, such as Fouriertransform infrared spectroscopy (FTIR), scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDX), highresolution transmission electron microscopy (HRTEM), and a vibrating sample magnetometer (VSM). The successful incorporation of HPA acid into the magnetite ZIF-8 nanocomposite was indicated by prominent bands in the FTIR analysis, and this formation was further validated by EDX analysis. The VSM results also revealed that the nanocomposite has good magnetic responsiveness, facilitating catalyst separation and recycling. The magnetic ZIF-8 composites functionalized with H6PV3MoW8O40 demonstrated significant potential for sustainable biodiesel production from WCO.

Zeolitic imidazolate framework improved vanadium ferrite: toxicological profile and its utility in the photodegradation of some selected antibiotics in aqueous solution

Zeolitic imidazolate framework improved vanadium ferrite (VFe2O4@monoZIF-8) was prepared to purify a ciprofloxacin (CP), ampicillin (AP), and erythromycin (EY) contaminated water system via a visible light driven photocatalytic process.

Increasing the dual-enzyme cascade biocatalysis efficiency and stability of metal-organic frameworks via one-step coimmobilization for visual detection of glucose.

In biosensing analysis, the activity of enzyme systems is limited by their fragility, and substrates catalyzed by monoenzymes tend to undergo spontaneous decomposition during ineffective mass transfer processes. In this study, we propose a novel strategy to encapsulate the glucose oxidase and horseradish peroxidase (GOx&HRP) cascade catalytic system within the hydrophilic zeolite imidazole framework ZIF-90. By leveraging the specific pore structure of ZIF-90, we effectively immobilized GOx and HRP molecules in their three-dimensional conformations, which improved the catalytic activity of the encapsulated enzymes compared with that of free GOx and HRP in various harsh environments. Additionally, our strategy reduced the occurrence of ineffective mass transfer and enhanced the sensitivity of the biosensor through an enzyme cascade system. When this biosensor was applied to serum samples containing complex biological matrices, the degradation of GOx&HRP by various proteases and the surface adsorption of diverse biomolecules were effectively prevented, thereby generating stable and reliable signals of glucose levels. The sensor shows remarkable sensitivity and selectivity for determining glucose concentrations ranging from 0 to 2.5 μg ml-1, with a detection limit as low as 0.034 μg ml-1. Furthermore, we developed a paper-based colorimetric sensor utilizing GOx&HRP@ZIF-90 integrated with a smartphone platform for the visual detection of blood glucose.

Coordination effect-adjusted Co in bimetallic zeolite imidazolate framework for efficient oxygen electrocatalysts

Fuel cells require low-cost, efficient, durable oxygen reduction catalysts. The utilization of metal-nitrogen-carbon (M-N-C) catalysts stemmed from zeolite imidazolium frameworks (ZIFs) holds immense promise in the realm of catalysis. In...

Investigation of hexanal removal through adsorption and photocatalysis on ZIF-7 modified with ZnO, TiO\(_2\), and ZnO/TiO\(_2\) using ATR-FTIR

Zeolitic imidazolate framework (ZIF) is renowned for its high adsorption capacity and frequently adsorbs organic pollutants. However, its high band gap energy has limited its photocatalytic activity, thus necessitating a modification for enhance performance enhancement. This study focuses on developing a ZIF-7 composite material that integrates adsorption and photocatalysis to remove volatile organic compounds (VOCs), particularly hexanal. Modifications were made by incorporating ZnO, TiO2, and ZnO/TiO2 via a solvothermal method using dimethylformamide (DMF). ATR-FTIR analysis was employed to monitor any changes in peak intensity related to the C=O vibrations of hexanal around 1700 cm-1. The results showed that all samples effectively adsorbed hexanal, reducing peak intensity after UV irradiation, and confirming successful photocatalysis. Notably, TiO2@ZIF-7 exhibited the highest photocatalytic performance with 88.06% degradation efficiency. This study confirms that the ATR-FTIR method can be used to monitor the success of adsorption and photocatalysis and shows the potential for developing composite materials to remove VOCs such as hexanal.

2D Mesoporous Carbon with Hollow Turtle Shell‐Like Morphology for Resolving Restacking Effect

AbstractIn this work, a unique 2D hollow turtle shell‐like mesoporous carbon (HTMC) synthesized via a ternary heterostructuring strategy to alleviate the restacking tendency of 2D materials is presented. The ternary 2D heterostructuring is achieved via an in situ growth of zeolitic imidazolate framework‐8 (ZIF‐8) on graphene oxide (GO) and a subsequent mesostructured polydopamine (mPDA) coating to obtain ternary heterostructured GO@ZIF‐8@mPDA, which is then converted to the hierarchically porous HTMC having macro‐, meso‐, and micropores via direct carbonization. Additionally, 2D turtle shell‐like microporous carbon (TMC) and 2D mesoporous carbon (MPC) derived from binary heterostructured GO@ZIF‐8 and GO@mPDA, respectively, are synthesized to investigate the porosity effect on alleviating the loss of accessible surface area of restacked 2D carbons. Among them, HTMC demonstrates superior structural advantages for alleviating the negative effects of restacking in 2D materials, exhibiting by far the highest specific capacitance (Csp) across all scan rates (93.7 F g−1 at 500 mV s−1 to 334.47 F g−1 at 1 mV s−1) in 1 M H2SO4. Furthermore, HTMC demonstrates outstanding rate capability while maintaining the greatest charge storage capacity over all scan rates.

Dual‐Loading Strategy Constructing Smart Coatings With Novel Hydroxyapatite/ZIF‐8 Composites

ABSTRACTThe marine environment with high humidity and salinity poses higher requests on the service life of traditional polymer coatings therefore, various fillers have been developed for modification. Smart coatings built by fillers that possesses passive barrier and active self‐healing properties show considerable prospects in metal protection. Herein, we applied a novel dual‐loading strategy to design tannic acid (TA) decorating hydroxyapatite (HAp)/zeolite imidazole framework (ZIF‐8) loading 2‐amino benzothiazole (2‐ABT) composite fillers. The epoxy coating (EP) doped with ABT@ZIF8‐HAp@TA (AZHT/EP) presented hydrophobicity and improved mechanical performance on Q215 steel. Moreover, the |Z|f=0.01Hz of AZHT/EP after immersion in saline water for 28 days (6.24 × 1010 Ω•cm2) is higher than pure EPs with two magnitudes. The anticorrosion mechanism of the AZHT/EP was proposed based on the analysis of corrosion products. To conclude, the dual‐loading strategy has considerable potential in designing smart coatings for corrosion protection in harsh environments.

Three-Dimensional Zeolitic Imidazolate Framework-8 as Sorbent Integrated with Active Capillary Plasma Mass Spectrometry for Rapid Assessment of Low-Level Wine and Grape Quality-Related Volatiles.

The most commonly used methods to chemically assess grape and wine quality with high sensitivity and selectivity require lengthy analysis time and can be resource intensive. Here, we developed a rapid and non-destructive method that would help in grading and decision support. In this work, we demonstrate that integrating a three-dimensional (3D) material for volatile sampling with mass spectrometry detection can be used to sample grapes for phytosanitary, quality or smoke-taint assessments at low levels of marker compounds. An efficient zeolitic imidazolate framework-8 (ZIF-8) material was synthesised in situ on nickel foam (NF), taking advantage of its ultrahigh surface area, structural diversity, and functionality as an emerging nanostructured material for preconcentrating low-level wine and grape quality-related volatiles. When used as a sorbent in thermal desorption tubes and coupled directly to active capillary mass spectrometry, the average signal across the selected analytes increased by ~50% as compared to Tenax TA, a commercially available polymer, in a measurement that takes less than two minutes. The first integration of 3D materials into mass spectrometry opens new possibilities for developing new material architecture with enhanced selectivity of next-generation multifunctional instrumentation for volatile analysis and product quality assessment.

A Bone‐Targeting Hydrogen Sulfide Delivery System for Treatment of Osteoporotic Fracture via Macrophage Reprogramming and Osteoblast‐Osteoclast Coupling

AbstractThe demand for systemic treatment of osteoporotic fractures to reduce recurrence is increasing, but current anti‐osteoporosis medications exhibit unsatisfactory efficacy due to adverse events and limited effects on fracture healing. Herein, a bone‐targeting zeolitic imidazolate framework‐8 (ZIF)‐based hydrogen sulfide (H2S) delivery system (ZIF‐H2S‐SDSSD) is designed to simultaneously promote fracture healing and alleviate osteoporosis. With bone‐targeting peptide SDSSD grafted on the surface, ZIF‐H2S‐SDSSD nanoparticles release H2S in bone tissues without affecting the serum H2S level, thereby mitigating potential risks of systematic H2S delivery. Upon cellular uptake, the acidic environment in lysosomes drives the release of H2S from the encapsulated zinc sulfide in conjunction with the degradation of ZIF. The synergistic effects of released Zn2+ and H2S promote macrophage metabolic reprogramming by suppressing succinate accumulation and mitochondrial reactive oxygen species (mtROS) production, and further regulate osteoblast‐osteoclast coupling. Overall, this strategy holds great promise in the clinical treatment of osteoporotic fractures and broadens the application of nanomedicine therapy for orthopedic diseases.

Bioactive zeolitic imidazolate framework nanoconjugates as synergistic drug delivery agents for cancer nanotherapeutics.

The increasing effective, detectable, and targeted anticancer systems are driven by the growing cancer incidence and the side effects of current drugs. Natural products like saponin and apigenin have emerged as valuable compounds for precise treatment. Recent advancements in bioactive metal-organic frameworks (MOFs) have introduced multifunctional particles suitable for cellular imaging, targeted drug delivery, and early cancer treatment. In this study, bioactive ZIF-67 and ZIF-8 materials were synthesized, incorporating zinc nitrate and natural bioactive compounds such as saponin and apigenin to sensitize and deliver the material to damaged cancer tissue. The characterization of these bioactive nanostructures involved FT-IR, TEM, EDX, FESEM, and BET analysis. The study quantified the loading and release of natural products within the ZIF structure. Cytotoxicity assessments of drug-loaded MOFs were conducted on human oral cavity carcinoma cell lines OSCC, Hep-G2, Raji, MCF-7, and PDL under in vitro conditions. Flow cytometry analysis identified the combination of bioactive ZIF-67 and saponins as the most effective in inducing apoptosis. Finally, a novel synthesis of bioactive MOF compounds was developed with dual applications: drug delivery and cancer imaging, featuring a unique attribute that minimizes side effects on normal cells.

Deciphering the Antimicrobial and Antibiofilm Efficiency of Thyme Essential Oil Encapsulated Zeolitic Imidazole Framework-8 Against Foodborne Pathogens.

Food Packaging using antibacterial substances plays a vital role in food industry in controlling contamination caused by food borne pathogens. Stability and pH dependent degradation characteristics of zeolitic imidazole framework-8 (ZIF-8) makes its suitable candidate for biomedical applications. The present study focuses on thyme essential oil (TEO) encapsulated in ZIF-8 to achieve a synergistic antibacterial effect and prolonged drug release, aiming to extend the shelf life of food products. Optical, structural and surface characterizations of TEO encapsulated within ZIF-8 (ZIF-8@TEO) reveals successful incorporation of TEO into ZIF-8 nanoparticles. High drug loading and pH dependent release rate with higher release rate at acidic condition (75%) makes ZIF-8 a promising drug delivery system. ZIF-8@TEO exhibited potent antimicrobial against Staphylococcus aureus, Bacillus subtilius and Pseudomonas aeruginosa, also attenuated the biofilm forming ability of these food borne pathogens. In vitro and in vivo toxicity studies reveal the non-hemolytic and non-toxic nature indicating its biocompatible nature. The results of the study reveal that ZIF-8@TEO nanoconjugate can be used for the development of novel antibacterial nanocomposite-based films for food packaging applications.

Carbon Nanostructures Derived from In Situ Grown ZIF Nanocages within Bacterial Cellulose for AC-Filtering Electrochemical Capacitors.

Electrochemical capacitors (ECs) offer superior specific capacitance for energy storage compared to traditional electrolytic capacitors but face limitations in alternating current (AC) filtering due to the need for balancing fast response and high capacitance. This study addresses these challenges by developing a freestanding nanostructured carbon electrode, derived from the rapid carbonization of bacterial cellulose (BC) embedded with zeolitic imidazolate framework 8 (ZIF-8) and in situ formed carbon nanotubes (CNTs). The electrode exhibits an exceptionally low area resistance of 9.8 mΩ cm2 and a high specific capacitance of 2.1 mF cm-2 at 120Hz, maintaining performance even at high frequencies. Stacking these electrodes enhances the capacitance to 5.3 mF cm-2, with the phase angle degrading to -74.4° at 120Hz; however, they retain a phase angle below -45° up to ≈50kHz, demonstrating excellent high-frequency performance. Furthermore, connecting three aqueous units in series as an integrated cell or utilizing organic electrolytes extends the voltage window to 2.4V, enhancing their suitability for high-voltage applications. Ripple voltage analysis under various loads and frequencies indicates effective filtering capabilities, highlighting the potential of these nanostructured ECs for next-generation electronic applications.

Structurally Stable Hollow-Fiber-Based Porous Graphene Oxide Membranes with Improved Rejection Performance by Selective Patching of Framework Defects with Metal-Organic Framework Crystals.

Graphene oxide (GO)-based membranes have demonstrated great potential in water treatment. However, microdefects in the framework of GO membranes induced by the imperfect stacking of GO nanosheets undermine their size-sieving ability and structural stability in aqueous systems. This study proposes a targeted growth approach by growing zeolitic imidazolate framework-8 (ZIF-8) nanocrystals precisely to patch microdefects as well as to cross-link the porous graphene oxide (PGO) flakes coated on the outer surface of the hollow fiber (HF) alumina substrate (named the hybrid PGO/ZIF-8 membrane). This method simultaneously improves their structural stability and size-sieving performance without compromising their water permeance. Various structural and elemental analyses were used to elucidate the targeted growth of the ZIF-8 crystals. The X-ray photoelectron spectroscopy (XPS) analysis confirmed the targeted coordination interaction of oxygen moieties on the edges of PGO nanosheets with metal ions of ZIF-8 crystals, allowing for the precise growth of the ZIF-8 nanocrystals in the PGO membranes. The XPS depth profile analysis revealed the uniform distribution of the ZIF-8 precursor throughout the PGO/ZIF-8 membrane. The resultant membrane showed a water permeance of 4 L m-2 h-1 bar-1 and maintained a very stable performance under pressure and prolonged cross-flow operation. Notably, the molecular weight cutoff (MWCO) improved considerably from 570 to 320 g/mol without sacrificing any water permeance after the targeted growth of ZIF-8. This research paves the way for the preparation of highly selective and stable PGO-based membranes for applications in industrial wastewater treatment.

Cytotoxic effects of bee venom-loaded ZIF-8 nanoparticles on thyroid cancer cells: a promising strategy for targeted therapy.

Thyroid cancer continues to be a notable health issue, requiring the creation of novel treatment methods to enhance patient results. The objective of this study is to investigate the potential of utilizing bee venom (BV)-loaded zeolitic imidazolate framework-8 (ZIF-8) nanoparticles as a novel strategy for specifically targeting and treating medullary thyroid cancer cells. Due to their wide surface area and configurable pore size, ZIF-8 nanoparticles are ideal for drug delivery. Bee venom's cytotoxic capabilities are used in ZIF-8 nanoparticles to target thyroid cancer cells more effectively. ZIF-8 nanoparticles containing bee venom were tested on TT medullary thyroid cancer cell lines. The effects of these nanoparticles on cell viability, proliferation, and apoptosis were investigated. IC50 value at 24h for BV-ZIF-8 nanoparticles in TT medullary thyroid carcinoma cells was determined to be 17.19µg/mL, while the IC50 value at 48h was determined to be 16.39µg/mL. It has been demonstrated that nanoparticle treatment upregulates the Bax and caspase-3 genes while downregulating the Bcl-2, CCND1, and CDK4 genes. Additionally, it was observed that oxidative stress was triggered in the nanoparticle-treated group. Furthermore, an examination of its mechanisms was conducted, with a specific emphasis on the modulation of critical signaling pathways that are implicated in the progression of cancer. In thyroid cancer cells, ZIF-8 nanoparticles infused with bee venom promote programmed cell death and impair key biological processes.

Recent Advances in Single‐Atom Catalyst for Solar Energy Conversion: A Comprehensive Review and Future Outlook

AbstractSingle‐atom catalysts (SACs) are becoming increasingly recognized as highly promising catalytic materials, distinguished by their exceptional atomic efficiency, superior selectivity, and elevated activity levels. This review offers a detailed and comprehensive overview of the recent advancements in SACs, focusing on synthesis strategies, photocatalytic energy conversion applications, and advanced characterization techniques. Various synthetic approaches for fabricating atomically dispersed catalysts are elaborated concisely, emphasizing the importance of achieving precise atomic regulation on compatible supports to ensure strong metal–support interactions. Furthermore, the advanced characterization techniques by analytical tools are illustrated for a deep exploration of catalytic activity and mechanistic insights into uniformly dispersed SACs. Specifically, different kinds of support materials such as metal–organic frameworks (MOFs), their subset zeolitic imidazolate frameworks, and graphitic carbon nitride (g‐C3N4) with diverse coordination and electronic environments are examined. Further, advances in computational techniques and machine learning are transforming SACs development by improving predictive accuracy and reducing trial‐and‐error methods, thereby accelerating the discovery of stable and active catalysts. Finally, current challenges and prospects of SACs based on MOFs, and g‐C3N4 are addressed, providing valuable insights for the continued development and application of these catalysts in various industrial processes and environmental remediation efforts.

Engineering of HO-Zn-N2 Active Sites in Zeolitic Imidazolate Frameworks for Enhanced (Photo)Electrocatalytic Hydrogen Evolution.

Currently, lack of ways to engineer specific and well-defined active sites in zeolitic imidazolate frameworks (ZIFs) limits our fundamental knowledge with respect to the mechanistic details for (photo)electrocatalytic hydrogen evolution reaction (HER). Here, we introduce the open metal sites into ZIFs through the selective ligand removal (SeLiRe) strategy, comprehensively characterize the altered structural and electronic features, and evaluate their role in HER. In-situ electrochemical analysis and X-ray absorption spectroscopy reveal the formation of high-valence HO-Zn-N2 sites through the binding of Zn-N2 with electrolyte hydroxide. The optimal OMS-ZIF exhibits a low overpotential of 0.41 V to achieve an ampere-level 1.0 A cm-2 with 120-hour stability. Theoretical simulations indicate that these active sites accelerate the water molecules activation kinetics, consequently enhancing the efficiency of the Volmer step. This work demonstrates a versatile strategy to introduce highly active catalytic sites in ZIFs, providing new insights into the electrocatalytic mechanism in alkaline media.

Construction of silver-doped graphitic carbon nitride integrated zeolitic imidazolate framework as an ultra-sensitive probe for colorimetric detection application

Abstract Malachite green, and phloxine B are highly effective antifungal, and antibacterial agents utilized primarily in aquaculture. It is classified within the Triarylmethane dye. Numerous studies have indicated that malachite green, and phloxine B are significantly toxic to both terrestrial and aquatic organisms. More critically, it poses substantial risks to human health and safety. As a result, several governments have prohibited its application in aquaculture and food production. There is a pressing need to develop a novel colorimetric probe for the detection of malachite green, and phloxine B. In response, a composite material was synthesized, combining Zeolitic Imidazolate Framework (ZIF-8) with silver-doped graphitic carbon nitride (Ag-g-C3N4), to serve as a colorimetric probe for the sensitive and selective identification of malachite green, and phloxine B. The Ag-g-C3N4/ZIF-8 composite demonstrated exceptional colorimetric sensing capabilities, attributed to the synergistic interactions between ZIF-8 and Ag-g-C3N4, achieving a detection limit as low as 1.073 nM, and 1.214 nM, for malachite green, and phloxine B, respectively. This composite represents a significant advancement in environmental sensing technology, providing a versatile and effective approach for detecting and addressing contamination in water resources.

Cobalt-Based ZIF Composite Membranes: In Situ Defect Engineering for Enhanced Water Stability and Gas Separation.

Porous coordination polymers with excellent molecular sieving ability, high dispersibility, and good compatibility with engineered polymer matrices hold promise for various industrial applications, such as gas separation and battery separators. Here, an in situ defect engineering approach is proposed for highly processable cobalt (Co)-based zeolitic imidazolate frameworks (ZIFs) with enhanced molecular sieving ability and water stability. By varying alkylamine (AA)modulators, the pore structures and textural properties of ZIFs can be fine-tuned. The resulting high-loading composite membrane exhibits excellent C3H6/C3H8 separation performance and mechanical properties. This in situ defect engineering approach enables efficient interfacial engineering for high-performance composite membranes.

Bioinspired Spatial Compartment of Substrate Molecules and Catalytic Counting Entities in Hierarchical MOFs Initiated for a Dual-Mode Glycoprotein Assay.

Living cell systems possess multiple isolated compartments that can spatially confine complex substances and shield them from each other to allow for feedback reactions. In this work, a bioinspired design of metal-organic frameworks (MOFs) with well-defined multishelled matrices was fabricated as a hierarchical host for multiple guest substances including fluorogenic molecules and catalytic nanoparticles (NPs) at the separated locations for the development of a dual-mode glycoprotein assay. The multispatial-compartmental zeolitic imidazolate framework-8 (ZIF-8) constituents were synthesized via epitaxial shell-by-shell overgrowth to guide the integration and spatial organization of host guests. The specific property toward glycoprotein recognition was guaranteed by both the antibody-antigen recognition and covalent bonding through boronate-glycan affinity, and the immediate signal responses were initiated by textural collapse of the ZIF-8 integrity. In addition, the inner micropore and the enclosed space of ZIF-8 can avoid the surpassed contact between molecular substances and catalytic entities, inherently. Furthermore, multishelled ZIF-8 can function as a hierarchical matrix for hosting abundant fluorogenic substrates and a large number of catalytic Pt-shelled Au (AuPt) NPs, which can signify its signal amplification means, while upon the stimuli-responsive framework collapse, the signal generators can be harvested in the on-demand manner. Besides, endowing Pt shells on inert plasmonic NPs can not only mimic peroxidase-like catalytic behavior involved in a fluorogenic catalytic reaction to generate fluorescence signals but also function as scattering signal reporters, which can also signify the dynamic light scattering output signals. Collectively, our proposed method may provide a new thought in combining the well-defined multishelled MOF matrices for dual-signal generators in a stimuli-responsive manner, which can also reinforce the accurate detection capability for the glycoprotein assay.