Zeolitic Imidazolate Framework Research Articles

Coordination-Driven Templated Synthesis of Hierarchically Porous Zeolitic Imidazolate Frameworks for Cascade Enzyme Cycle Amplification Coupled Immunoassay.

Although hierarchically porous zeolitic imidazolate frameworks (HPZIFs) not only inherit the intrinsic architectural and chemical stabilities of their microporous counterparts but also afford open space for the efficient mass diffusion of the macromolecules involved, their rational design and construction are still challenging. Herein, HPZIFs with tailorable pore sizes ranging from 18 to 54 nm were successfully fabricated by using a newly developed soft-template-directed strategy. Our success rooted in the fact that the screened PS81-PVP44-PEO113 triblock copolymer could effectively coordinate with the metal precursor for the directed crystallization of ZIFs along surfactant assemblies. The advantages of continuous large pores and open structures in such HPZIFs were fully taken into account to serve as a bioreactor for the efficient immunoassay. The expanded large pores provided not only a significantly vast surface area to enhance the density of capture antibodies but also enough space for accommodating multiple conjugated biomolecules in one pore channel. In combination with a cascade enzyme cycle amplification strategy, a model biomarker of prostate-specific antigen (PSA) at the femtomolar level was checked with a limit of detection of 92 fM using the developed immunosensor. Specific screening on patients with prostate cancer or even benign prostatic hyperplasia was exemplified through accurately quantifying small changes of PSA concentration in clinical serum samples, prefiguring the great potential of the developed HPZIF-8 immunosensor platform for the early monitoring and diagnostics of diseases.

Strategic Fabrication of Au4Cu2 NC/ZIF‐8 Composite Via In Situ Integration Technique for Enhanced Energy Storage Applications

AbstractMetal–organic frameworks (MOFs), known for their extensive porosity and versatile crystallinity, play a crucial role in the development of advanced energy storage materials. However, their application is limited by stability and conductivity issues. This study addresses these challenges by integrating ultrasmall metal nanoclusters, specifically Au4Cu2 NC, synthesized using a mixed ligand strategy combining 2, 4‐Dimethyl benzene thiol (2,4‐DMBTH) and 1,2‐bis(diphenylphosphino)ethane (dppe). The bimetallic Au4Cu2 NC, characterized by Single Crystal X‐Ray Diffraction (SCXRD), is applied to zeolitic imidazolate framework‐8 (ZIF‐8) using both in situ and ex situ methods to explore their electrochemical and physicochemical properties in energy storage. The in situ Au4Cu2 NC/ZIF‐8 composite demonstrated a specific capacitance that is almost two times higher than its ex situ counterpart, attributed to homogeneous dispersion and hence enhanced conductivity. This in situ integration of atomically precise bimetallic nanoclusters on MOFs significantly boosts supercapacitor performance, offering a more effective and reliable solution for energy storage. Further, in practical applications, this device demonstrated an energy density of 87.2 Wh kg−1 at a power density of 1474 W kg−1, highlighting its robustness and potential for high‐performance energy storage applications. This approach effectively combats the issue of nanocluster aggregation on substrates, marking a significant progression in supercapacitor technology.

Facile metal-oriented in-situ growth of zeolitic imidazole framework membranes on carbon fiber cloth with superior capacitive performance

Facile metal-oriented in-situ growth of zeolitic imidazole framework membranes on carbon fiber cloth with superior capacitive performance

Zeolitic Imidazolate Framework-8 enhanced with tungsten carbide for high-performance hybrid supercapacitors and hydrogen evolution

A promising metal-organic framework (MOF) called Zeolitic Imidazolate Framework-8 (ZIF-8) stands out for its electrochemical applications. Its versatility in physicochemical properties makes it a strong candidate for breakthroughs in energy storage and electrochemical water splitting. The electrode nanomaterials lower specific capacity, small charging/discharging rate, and low conductivity limit its supercapacitor and hydrogen evaluation reaction (HER) applications. The ZIF-8 zeolite structure was decorated with tungsten carbide (WC) to overcome these issues. These modifications result in improved porosity, surface area, density, and pore size, shape, and structure. These characteristics contribute significantly to enhanced electrochemical activity. ZIF-8 MOF/WC nanocomposites have excellent dispersion and stability due to their porosity and strong connection between embedded WC nanoclusters and the framework. The prepared electrode showed a 118.11 mV overpotential and 36.45 mV/dec Tafel slope throughout HER activity. ZIF-8 MOF/WC was used for electrochemical studies and to make a hybrid energy storage device using activated carbon (AC). The hybrid supercapacitor had higher energy and power densities (87 W h/kg and 850 W/kg). The theoretical technique (Dunn model) was also employed to analyze experimental results more thoroughly.

Zeolitic imidazolate framework-8 as a high-affinity adsorbent for dispersive solid-phase extraction in the analysis of plant growth regulators in fruits.

Facile and sensitive determination of plant growth regulators (PGRs) in food samples is crucial but still poses a significant challenge. In this study, to enhance the sensitivity of the HPLC-DAD method for PGR detection, a dispersive solid phase extraction (d-SPE) method using zeolitic imidazolate framework-8 (ZIF-8) as the highly effective adsorbent is developed. ZIF-8 nanoparticles are formed through the coordination of Zn2+ with 2-methylimidazole. Due to its high porosity, large surface area, abundant π electronics and nitrogen electronics, ZIF-8 exhibits a strong affinity to PGRs due to the synergistic effects of π-π interaction, van der Waals force, H-bond, and surface effect. Under the optimal d-SPE conditions, the sensitivity of the method is significantly enhanced with outstanding performances, including a wide range of linearity (2.0-200 ng g-1) with high correlation coefficients (R ≥ 0.9989), low limits of detection (LODs, 0.9-8.0 ng g-1 for all PGRs), satisfactory precision (intra-day RSDs ≤ 3.3%, inter-day RSDs ≤ 4.2%), and high accuracy (recovery: 86.6-101.5%). The developed method was successfully applied to quantitatively detect 9 PGRs in fruit samples, yielding satisfactory results. This d-SPE-HPLC-DAD method, characterized by high sensitivity, simplicity, efficiency, ease of practice and cost-effectiveness for PGR detection, shows potential for detecting PGRs in other complex samples and provides a strategy for designing target-affinity adsorbents.

Smart Bandage Based on a ZIF-8 Triboelectric Nanogenerator for In Situ Real-Time Monitoring of Drug Concentration.

For chronic wounds, frequent replacement of bandages not only increases the likelihood of secondary damage and the risk of cross infection but also wastes medication. Therefore, in situ real-time monitoring of the concentrations of residual drugs in bandages is crucial. Here, we propose a novel strategy that combines a triboelectric nanogenerator (TENG) with medical bandages to develop a smart bandage based on zeolite imidazolate framework TENG. During the process of wound healing, the electrical output of TENG changes with the continuous release of drugs. Based on the correlation between the electrical signal of TENG and drug concentration, the concentration of residual drugs in the bandage can be monitored in real-time in situ, guiding medical staff to replace the bandage at the most appropriate time. The smart bandage based on TENG provides a new strategy for in situ real-time monitoring of drug concentration and also provides an ideal and feasible solution for the field of biomedical drug sensing.

Pore-Specific Anisotropic Etching of Zeolitic Imidazolate Frameworks by Carboxylic Acid Vapors.

Anisotropic etching is a powerful way to customize metal-organic frameworks with advanced nanostructures, but it is still in its infancy. Herein, we proposed an unprecedented etching strategy that created anisotropic hollow structures in various zeolitic imidazolate framework (ZIF) nano/single crystals via pore-specific carving. The etching occurred through a newly discovered gas-solid reaction where carboxylic acid vapors bind with ligands in ZIFs at room temperature to form ionic liquid (IL). A series of experiments were conducted to decode the origin of anisotropy and the "hollowing out" effect. We found that large pore openings on {111} facets provide access for the entry of carboxylic acid vapors and the outflow of the IL, resulting in pore-dependent anisotropy features. The unique "etching after adsorption" mechanism and the adsorption capacity of the IL enable acid vapors to hollow out nanocrystals and even single crystals. By altering carboxylic acids and ligands in ZIFs, the etching process can be precisely tuned from the inside out or the outside in. This new method demonstrates broad universality and brings unprecedented morphologies and complexities. It may offer great opportunities for achieving purposeful modification of ZIFs and the rational construction of intricate architectures.

Insights into Amorphous Metal‐Organic Framework as Carbonic Anhydrase Mimic

AbstractCarbonic anhydrase (CA) is an important enzyme which breaks the C−O bond and catalyzes the hydration of CO2 and developing artificial enzyme to mimic the function of CA is important for the related applications. Zeolitic imidazolate frameworks (ZIFs) with typical tetrahedral Zn−N coordination units which were similar to the catalytically active site of natural CA have been reported to displayed CA‐like activities. However, the activity of crystalline ZIFs remains unsatisfactory. Herein, amorphous zeolitic imidazolate framework (aZIF) was fabricated through a facile self‐assembly process and exhibited 2.2‐fold higher CA‐like hydrolytic activity than the corresponding crystalline ZIF‐8.This phenomenon can be ascribed to the unsaturated Zn−N coordination structure and mesopores inside aZIF. This work affords a new avenue for the rational design of nanozymes.

Ratiometric fluorescent determination of sulfadimethoxine in foods based on a dual-emission metal-organic framework.

Ratiometric fluorescence detection is endowed with higher accuracy than single fluorescence signal assay. In this work, we construct a ratiometric fluorescence probe for the facile quantification of sulfadimethoxine (SDM) in foods. By wrapping N-doped carbon dots (N-CDs) and gold nanoclusters (AuNCs) into zeolitic imidazolate framework-8 (ZIF-8), the nanocomposite of N-CDs/AuNCs@ZIF-8 is facilely prepared and emits two fluorescence including 475nm from N-CDs and 650nm from AuNCs. Since bovine serum albumin (BSA) is the stabilizer of AuNCs, SDM can form a complex with BSA, resulting in the fluorescence quenching of AuNCs at 650nm by a static quenching mechanism. In contrast, SDM has a rare influence on the fluorescence of N-CDs (475nm). As a result, the use of the probe of N-CDs/AuNCs@ZIF-8 for SDM detection enables simultaneous measurement of response signal and reference signal. Under the optimal condition, the SDM assay based on the probe has a good linear relationship within 10 to 2 × 106ng/mL and the limit of detection (LOD) is low to 1.064ng/mL. In addition, the fluorescent probe shows good reliability for the detection of SDM in practical food samples.

Rational Construction of a 3D Self-Supported Electrode Based on ZIF-67 and Amorphous NiCoP for an Enhanced Oxygen Evolution Reaction.

The development of efficient and Earth-abundant electrocatalysts for the oxygen evolution reaction (OER) is an urgent requirement in the field of electrochemical water splitting. The electrocatalytic performance of the OER can be greatly enhanced by the synergistic combination of zeolite imidazolate frameworks (ZIFs) and transition-metal phosphides, both of which individually exhibit promising capabilities in this regard. In this study, a novel amorphous NiCoP deposited on ZIF-67 sheets supported on Ni foam (labeled as NiCoP/ZIF-67/NF) as an OER electrocatalytic material was successfully synthesized using a simple, secure, and time-efficient two-step strategy. The experimental results demonstrate that NiCoP/ZIF-67/NF possesses a large active surface area with abundant active sites. Also, the synergistic effect and interaction between NiCoP and ZIF-67, as well as between Ni and Co within NiCoP, effectively enhance its electrochemical performance under alkaline conditions. Consequently, NiCoP/ZIF-67/NF exhibits outstanding catalytic activity for OER with an overpotential (η) of 175 mV at a current density of 10 mA cm-2 and a long-term stability over 40 h at 20 mA cm-2 in a 1.0 M KOH electrolyte. The corresponding analyses suggest that the real active sites responsible for the OER are identified as NiOOH and CoOOH species within the structure of NiCoP/ZIF-67/NF. Additionally, the catalytic function and stability of ZIF-67 toward the OER under alkaline conditions were also briefly discussed. This work provides a novel catalytic material for the OER along with a facile strategy to fabricate superior, efficient, and noble metal-free catalysts suitable for energy-related applications.

A novel metal‐organic framework encapsulated iridium oxide nanozyme enhanced antisense oligonucleotide combo for osteoarthritis synergistic therapy

AbstractOsteoarthritis (OA) is associated with metabolic imbalance of articular cartilage and an increase of intracellular reactive oxygen species (ROS). Synergistic therapy based on the codelivery of ROS scavengers and antisense oligonucleotides (ASO) into chondrocytes has the potential to effectively treat OA. Here, we developed a novel biocompatible metal‐organic framework (MOF)‐encapsulated nanozyme/ASO delivery platform (miR/IrO2@ZIF‐8) for OA treatment. IrO2 nanoparticles with the catalytic activities of superoxide dismutase/catalase were synthesized using a hydrothermal method, resulting in excellent ROS scavenging performance. IrO2 was further loaded into zeolitic imidazolate framework‐8 (ZIF‐8) to maintain its catalytic efficacy and regulate its size, surface charge, and biocompatibility to enhance the therapeutic effect of the platform. As an effective ASO delivery carrier, the synthesized IrO2@ZIF‐8 exhibited high antagomiR‐181a loading and lysosomal escape capacity, enabling it to rebalance cartilage metabolism. In vitro experiments showed that miR/IrO2@ZIF‐8 could restore ROS levels, mitochondrial membrane potential, and lipid peroxidation in chondrocytes. At the same time, the expression levels of proinflammatory markers (IL‐1β, IL‐6, and COX‐2) as well as the extracellular matrix degrading enzymes (ADAMTS‐5 and MMP13) were downregulated, indicating effective antioxidant, anti‐inflammatory, and anticartilage degradation effects. Notably, miR/IrO2@ZIF‐8 was able to deliver IrO2 nanoparticles and antagomiR‐181a to the cartilage tissue at a depth of up to 1.5 mm, thus solving the problems of poor permeability and difficult retention of drugs in cartilage tissue. This further improves the synergistic therapeutic effect on OA by inhibiting cartilage degradation. The combination of MOF‐encapsulated IrO2 nanozymes with antagomiR‐181a has an excellent therapeutic effect on OA, offering a promising translational medicine paradigm.

Aggregation and Sedimentation Stability of Nanoscale Zeolitic Imidazolate Framework (ZIF‐8) Nanocomposites for Antimicrobial Agent Delivery Applications

ABSTRACTThe applications of nanoscale zeolitic imidazolate frameworks (ZIF‐8) for antimicrobial drug delivery depend on the aqueous suspension stability of the ZIF‐8 which is influenced by their crystallinity, size, shape, aggregation, and surface chemistry. This study evaluated the stability of ZIF‐8 nanoparticles in terms of their aggregation and sedimentation characteristics. ZIF‐8 nanocomposites were synthesized with methanol via sonication at 30°C for 1 h. The effect of drying methods (oven drying at 80°C, and vacuum drying at 35°C), number of washing steps (0 = no wash, 1, 2, 3), and washing medium (washing with water and ethanol instead of methanol, and redispersion in water and ethanol) on the suspension stability was evaluated. The impact of added xanthan gum (XG) and poly‐L‐lysine (PL) as suspension media was also evaluated. ZIF‐8 nanoparticles were also synthesized using ethanol and suspended in PL. % transmittance and zeta potential were measured for freshly prepared ZIF‐8 suspensions in PL and after freeze‐drying and resuspending in water. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and x‐ray diffraction (XRD) analysis were utilized for the assessment of the crystallinity, structure, and morphology of the samples. Antibacterial activity was evaluated by disc diffusion test against Escherichia coli. Dried methanol‐synthesized ZIF‐8 nanoparticles did not suspend in water; only the ZIF‐8 nanoparticles synthesized with reduced washing times and no drying treatment were resuspended in the water, XG and PL solutions. Instead, the ethanol‐synthesized ZIF‐8 nanoparticles were resuspended in water even after being washed three times and dried in a vacuum oven. SEM and TEM images and XRD patterns showed that alcohol can form well‐defined ZIF‐8 nanoparticles. FTIR spectra showed that ZIF‐8 had typical peaks of ZIF‐8 reported by others. Although particle size increased, the PL coating provided a 32.22% increase in zeta potential of ZIF‐8 nanoparticles from 36.25 to 47.93 mV (p < 0.05) and prevented aggregation and sedimentation of the nanoparticles without changing their morphology. All the tested ZIF‐8 nanoparticles showed antibacterial activity with the PL‐coated ZIF‐8 having the highest effect followed by the ZIF‐8 nanoparticles synthesized in ethanol.

Facile construction of copper-doped metal organic framework as a novel visible light-responsive photocatalyst for contaminant degradation

ABSTRACT Metal–organic frameworks (MOFs) with photocatalytic activity have garnered significant attentions in environmental remediation. Herein, copper-doped zeolitic imidazolate framework-7 (Cu-doped ZIF-7) was synthesized rapidly and easily using a microwave-assisted technique. Various analytical and spectroscopic methods were employed to access the framework, morphology, light absorption, photo-electrochemical and photocatalytic performance of the synthesized materials. Compared to ZIF-7, Cu/ZIF-7 (molar ratio of Cu2+ to Zn2+ is 1:1) demonstrates superior visible light absorption ability, narrower band gap, enhanced charge separation capability, and reduced electron–hole recombination performance. Under visible light irradiation, Cu/ZIF-7 serves as a Fenton-like catalyst and demonstrates exceptional activity for contaminant degradation, while virgin ZIF-7 remains inactive. With the addition of 9.8 mmol H2O2 and exposure to visible light for 30 min, 10 mg of Cu/ZIF-7 can completely decompose RhB solution (10 mg/L, 50 mL). The synergistic effect of the Cu/ZIF-7/H2O2/visible light system is attributed to visible light photocatalysis and Fenton-like reactions. Cu/ZIF-7 demonstrates excellent catalytic performance stability, with only a slight decrease in degradation efficiency from an initial 97.0% to 95.4% over four cycles. Additionally, spin-trapping ESR measurements and active species trapping experiments revealed that h+ and ·OH occupied a significant position for Rhodamine B (RhB) degradation. Degradation intermediate products of Rhodamine B have been identified using UPLC-MS, and the degradation pathways have been proposed and discussed. This work offers a facile and efficient technique for developing MOF-based visible light photocatalysts for water purification.

Bovine serum albumin-coated ZIF-8 nanoparticles to enhance antitumor and antimetastatic activity of methotrexate: in vitro and in vivo study

In this study, a bovine serum albumin-decorated zeolitic imidazolate framework (ZIF-8@BSA) was used to enhance the anticancer and antimetastatic properties of methotrexate. SEM, DLS, FT-IR, and XRD confirmed the physicochemical suitability of the developed nanoparticles. According to the SEM analysis, the mean size of ZIF-8 nanoparticles was 68.5 ± 13.31 nm. The loading capacity and encapsulation efficiency of MTX@ZIF-8@BSA were 28.77 ± 2.54% and 96.3 ± 0.67%, respectively. According to the in vitro hemolysis test, MTX@ZIF-8@BSA showed excellent blood compatibility. MTX@ZIF-8@BSA exhibited pH sensitivity, releasing more MTX at pH 5.4 (1.73 times) than at pH 7.4. The IC50 value of MTX@ZIF-8@BSA on 4T1 cells was 32.7 ± 7.3 µg/mL after 48 h of treatment, outperforming compared to free MTX with an IC50 value of 53.3 ± 3.7 µg/mL. Treatment with MTX@ZIF-8@BSA resulted in superior tumor growth suppression in tumor-bearing mice than free MTX. Furthermore, based on histopathology tests, MTX@ZIF-8@BSA reduced the metastasis in lung and liver tissues. While there was not any noticeable toxicity in the vital organs of MTX@ZIF-8@BSA-receiving mice, free methotrexate resulted in severe toxicity in the kidneys and liver. According to the preliminary in vitro and in vivo findings, MTX@ZIF-8@BSA presents an attractive drug delivery system candidate for breast cancer due to its enhanced antitumor efficacy and lower toxicity.

Silk Fibroin Microneedles Loaded with Lipopolysaccharide-Pretreated Bone Marrow Mesenchymal Stem Cell-Derived Exosomes for Oral Ulcer Treatment.

Oral ulcers, superficial lesions on the surface of the oral mucosa, have a high incidence rate, and their main symptoms include local pain and erosion. Lipopolysaccharide (LPS)-preconditioned bone marrow mesenchymal stem cells and their secreted exosomes (LPS-pre-Exos) have been shown to promote recovery in various inflammatory conditions and wounds. However, studies documenting LPS-pre-Exos as a therapeutic intervention for oral mucosal-like diseases are lacking. In this study, we prepared a silk fibroin microneedle (MN) patch consisting of LPS-pre-Exos and zeolitic imidazolate framework-8 (ZIF-8) that localized at the tip and base, respectively, and used this MN patch for oral ulcer treatment. Upon insertion into the oral mucosa, continuous LPS-pre-Exos release was observed, which promoted macrophage polarization and tissue healing. Additionally, the ZIF-8 framework in the MN patch facilitated the controlled release of Zn2+, which demonstrated potent antimicrobial properties via synergistic effects. The in vitro experimental results showed that the silk fibroin MN patch can continuously release LPS-pre-Exos and Zn2+ for more than 7 days. Thus, the LPS-pre-Exos and ZIF-8-loaded silk fibroin MN patch exhibited good anti-inflammatory and antibacterial properties, promoting oral ulcer healing, and showed good histocompatibility. Hence, it may represent a potentially valuable strategy for facilitating oral ulcer healing.

Fabrication of a Stable and Highly Effective Anode Material for Li-Ion/Na-Ion Batteries Utilizing ZIF-12.

Transition metal selenides (TMSs) are receiving considerable interest as improved anode materials for sodium-ion batteries (SIBs) and lithium-ion batteries (LIBs) due to their considerable theoretical capacity and excellent redox reversibility. Herein, ZIF-12 (zeolitic imidazolate framework) structure is used for the synthesis of Cu2Se/Co3Se4@NPC anode material by pyrolysis of ZIF-12/Se mixture. When Cu2Se/Co3Se4@NPC composite is utilized as an anode electrode material in LIB and SIB half cells, the material demonstrates excellent electrochemical performance and remarkable cycle stability with retaining high capacities. In LIB and SIB half cells, the Cu2Se/Co3Se4@NPC anode material shows the ultralong lifespan at 2000 mAg-1, retaining a capacity of 543 mAhg-1 after 750 cycles, and retaining a capacity of 251 mAhg-1 after 200 cycles at 100 mAg-1, respectively. The porous structure of the Cu2Se/Co3Se4@NPC anode material can not only effectively tolerate the volume expansion of the electrode during discharging and charging, but also facilitate the penetration of electrolyte and efficiently prevents the clustering of active particles. In situ X-ray difraction (XRD) analysis results reveal the high potential of Cu2Se/Co3Se4@NPC composite in building efficient LIBs and SIBs due to reversible conversion reactions of Cu2Se/Co3Se4@NPC for lithium-ion and sodium-ion storage.

ZIF-67-derived Co-N-C supported nickel cobalt sulfide as a bifunctional electrocatalyst for sustainable hydrogen production via alkaline electrolysis.

As non-renewable resources are finite and cannot be utilized indefinitely, hydrogen (H2) has emerged as a promising alternative for clean and sustainable energy. The cost-effective hydrogen production to meet large-scale commercial demand poses a significant challenge. Water electrolysis, powered by electricity derived from renewable resources, stands out as a viable route towards sustainable hydrogen production, with electrocatalysis playing a pivotal role in this process. Notably, materials derived from metal-organic frameworks (MOFs) exhibit excellent physicochemical properties, making them promising candidates for electrocatalysis. In this study, we synthesized zeolitic imidazolate framework-67 (ZIF-67) and its derived Co-N-doped carbon (Co-N-C) supported NiCo2S4 on nickel foam (NF), namely NF@ZIF-67@NiCo2S4 and NF@Co-N-C@NiCo2S4, using a hydrothermal method. The electrocatalytic activity of these synthesized materials for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) was systematically evaluated using various electrochemical techniques. The NF@ZIF-67@NiCo2S4 material demonstrates overpotentials of 248 and 359 mV for OER and HER at the current density of 50 mA cm-2, whereas, NF@Co-N-C@NiCo2S4 exhibits overpotentials of 239 and 351 mV, respectively. Furthermore, the catalysts exhibit excellent stability in both OER and HER even under high applied potentials. Moreover, to assess their catalytic performance in a full-cell configuration, two alkaline electrolyzer cells were assembled: NF@ZIF-67@NiCo2S4(+)∥NF@ZIF-67@NiCo2S4(-) and NF@Co-N-C@NiCo2S4(+)∥NF@Co-N-C@NiCo2S4(-). These two electrolyzers demonstrated cell potentials of 1.62 V and 1.59 V at 10 mA cm-2, respectively, showcasing their efficacy in overall water-splitting.

Fabrication of Highly Efficient ZIF-8@PEI Monoliths for CO2 Capture Using Phosphorylated Cellulose Nanofiber as a Binder.

This study involves the synthesis and comparison of zeolitic imidazolate frameworks (ZIFs), specifically ZIF-8 and ZIF-67 pristine with a commercial zeolite, emphasizing their CO2 affinity and sorption capability. To overcome challenges persisting in the handling and integration of these materials into industrial adsorption processes, particularly when limited to microcrystalline fine powders, we present herein an innovative manufacturing method to produce standalone monolithic supports. This process involves pseudoplastic paste formulations utilizing polyethylenimine (PEI) as a coagulant and locally fabricated phosphorylated cellulose nanofiber (PCNF) as a binding agent. Rheological investigation was conducted to anticipate the required shaping and design by means of paste flowability, consistency, and stiffness. XRD and FTIR results confirm the preservation of crystalline structure and the occurrence of amine functionalization associated with the presence of PEI, respectively. The proposed method significantly enhances the CO2 adsorption performance of the produced ZIF-8 monolith in comparison with that reached when using the pristine material, achieving a capacity of 1.25-2 mmol·g-1 at 30 °C under dry conditions in a pressure range of 1-13 bar, respectively. In other words, this work clearly highlights an effective applicability of the ZIF-8 monolith as an innovative sorbent for further designing CO2 capture industrial setups.

Confinement-Induced Biocatalytic Activity Enhancement of Light- and Thermoresponsive Polymer@Enzyme@MOF Composites.

Metal-organic frameworks (MOFs) are favorable hosting materials for fixing enzymes to construct enzyme@MOF composites and to expand the applications of biocatalysts. However, the rigid structure of MOFs without tunable hollow voids and a confinement effect often limits their catalytic activities. Taking advantage of the smart soft polymers to overcome the limitation, herein, a protection protocol to encapsulate the enzyme in zeolitic imidazolate framework-8 (ZIF-8) was developed using a glutathione-sensitive liposome (L) as a soft template. Glucose oxidase (GOx) and horseradish peroxidase (HRP) were first anchored on a light- and thermoresponsive porous poly(styrene-maleic anhydride-N,N-dimethylaminoethyl methacrylate-spiropyran) membrane (PSMDSP) to produce PSMDSP@GOx-HRP, which could provide a confinement effect by switching the UV irradiation or varying the temperature. Afterward, embedding PSMDSP@GOx-HRP in L and encapsulating PSMDSP@GOx-HRP@L into hollow ZIF-8 (HZIF-8) to form PSMDSP@GOx-HRP@HZIF-8 composites were performed, which proceeded during the crystallization of the framework following the removal of L by adding glutathione. Impressively, the biocatalytic activity of the composites was 4.45-fold higher than that of the free enzyme under UV irradiation at 47 °C, which could benefit from the confinement effect of PSMDSP and the conformational freedom of the enzyme in HZIF-8. The proposed composites contributed to the protection of the enzyme against harsh conditions and exhibited superior stability. Furthermore, a colorimetric assay based on the composites for the detection of serum glucose was established with a linearity range of 0.05-5.0 mM, and the calculated LOD value was 0.001 mM in a cascade reaction system. This work provides a universal design idea and a versatile technique to immobilize enzymes on soft polymer membranes that can be encapsulated in porous rigid MOF-hosts. It also holds potential for the development of smart polymer@enzyme@HMOFs biocatalysts with a tunable confinement effect and high catalytic performance.

A Structural Mimic of Carbonic Anhydrase in Zeolitic Imidazolate Frameworks via Trans-functionalization for Enhancing Hydrolytic Activity

A Structural Mimic of Carbonic Anhydrase in Zeolitic Imidazolate Frameworks via Trans-functionalization for Enhancing Hydrolytic Activity