Cobalt-based Metal-organic Framework Research Articles

MOF-derived yolk-shell CoN/Co-NC@SiO2 nanozyme with oxidase mimetic activities for colorimetric detection of glutathione

The development of nanozymes has garnered significant attention in biosensing applications owing to their exceptional catalytic properties and structural tunability. Herein, we present a yolk-shell nanozyme derived from metal-organic frameworks (MOFs) featuring CoN/Co-NC@SiO2 architecture, exhibiting remarkable oxidase mimetic activities for colorimetric glutathione (GSH) detection. The synthesis involves a facile pyrolysis process of cobalt-based MOFs encapsulated within a silica shell, resulting in a unique yolk-shell nanostructure with CoN/Co-NC active sites. Yolk-shell CoN/Co-NC@SiO2 has been studied in detail as an oxidase and catalase-like nanozyme. In consideration of structural and composition modulation, including hydrophilic SiO2 shell, the unique cavity, a high specific surface area and dispersed active sites, the CoN/Co-NC@SiO2 was proposed for colorimetric detection of glutathione with its oxidase-like activities. Based on the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) by CoN/Co-NC@SiO2, a wide linear detection range of 0.5–60 μM as well as a lower detection limit of 0.054 μM were obtained. Our research shows that optimizing structure and composition plays an important role in the construction of multiple-enzyme activity and offers bright potential applications of MOF-derived yolk-shell nanozymes in biosensing and medical diagnostics.

Optimization of Cobalt-Based MOFs for Super-Capacitor Electrode Materials of New Energy Vehicle

Super-capacitors (SCs), as new energy conversion storage elements, have attracted much attention, but there is still a research gap in the design of electrode materials. In this study, the optimization scheme of Metal-Organic Frameworks (MOFs) and cobalt-based MOF composites as electrode materials for SCs in new energy vehicles is explored, and a series of experiments are conducted to evaluate their performance. Scanning Electron Microscope (SEM) images reveal that the cobalt-based MOF composites have a surface morphology of particles with uniform distribution. The electrochemical performance test results show that the specific capacitance of the cobalt-based MOF composites is much higher than the sum of the two individual electrode materials and presents a remarkable increase with the scanning rate. Additionally, in the constant current charge-discharge test, cobalt-based MOF composites exhibit the longest charge-discharge time and good symmetry. Electrolyte particle contact tests for samples at different preparation temperatures display that high-temperature samples have better structural stability and electrolyte ion contact. In Cyclic Voltammetry (CV) and Galvanostatic Charge Discharge (GCD) tests, the 250°C sample demonstrates the best electrochemical properties and the highest specific capacitance (269 F/g). Moreover, as the current density increases, the specific capacitance of the 600°C sample decreases at a lower rate, showing stronger stability. However, the use of cobalt-based MOF materials may pose environmental and safety risks, such as the environmental impact of cobalt resource mining, instability under high-temperature conditions, and the possible production of hazardous substances. Therefore, these factors need to be fully considered when designing and using SCs to ensure the environmental friendliness and safety of cobalt-based MOFs. These results provide an important reference for selecting and optimizing electrode materials for SCs in new energy vehicles. Furthermore, this study offers research suggestions for improving new energy materials, filling the research gaps in related fields, and supporting the further development of SC technology.

From Co-MOF to Co@carbon–comparison of needle-like catalysts in photo-driven hydrogen evolution

In response to the rising demand for catalytic hydrogen production, more attention is focused on noble-metal-free catalysts such as cobalt-based metal–organic frameworks (MOFs) and their derivatives. Due to the varying activity of cobalt forms in photocatalytic processes, the present study explores the performance of photo-driven hydrogen generation of cobalt nitrilotriacetate (Co-NTA) with metal ions and MOF-derived carbons containing Co/CoOx/CoNx. The needle-like morphology of the obtained Co-NTA template was preserved in carbon materials prepared through carbonization with and without furfuryl alcohol. Carbons featured nitrogen-containing graphitic structures and oxygen functional groups. They were also characterized by a more developed specific surface area and larger pore volume compared to their parent MOF. All materials evolved hydrogen under visible light in a photosensitized system. Owing to the high content of metallic cobalt on the surface of non-impregnated carbon, it produced three times more hydrogen (14.2 mmol g−1) than Co-NTA.

Tracking the role of compressive strain in bowl-Like Co-MOFs structural evolution in water oxidation reaction

Dynamic structural evolution of catalyst active sites is crucial to for transition metal-catalyzed oxygen evolution reaction (OER). Yet, the elucidation of their mechanism behind the compressive-strain-induced reconstruction during OER process remains enigmatic. Here, we construct a bowl-like cobalt-based metal-organic frameworks (BL-Co-MOFs) catalyst with compressive strain to investigate the effect of strain on the structural evolution process and the OER mechanism. In situ techniques directly observe that compressive strain exists in the reconstruction of the potential-driven CoOOH-like active phase with contractile interatomic CoCo distance, promoting a direct OO radical coupling over the Co sites (Co−O−O−Co) during the OER process. This disrupts the constrains of the inherent linear scaling relationship and achieves the kinetic-faster oxide path mechanism (OPM) during OER process. Consequently, the BL-Co-MOFs exhibit a huge mass activity of 12516 A gmetal−1 and a large turnover frequency of 6888 h−1 at a low overpotential of 275 mV (300 mA cm−2).

Novel Tannic Acid-Modified Cobalt-Based Metal-Organic Framework: Synthesis, Characterization, and Antimicrobial Activity.

Metal-organic frameworks (MOFs) are a class of hybrid inorganic-organic materials with typical porous structures and a unique morphology. Due to their diversity, they are extensively used in a wide range of applications such as environmental, catalysis, biomedicine, etc. In this study, a novel cobalt-based MOF modified with tannic acid (Co-TPA/TA) (TPA: terephthalic acid; TA: tannic acid) as a promising material for antimicrobial agents was synthesized and characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy with energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, inductively coupled plasma-optical emission spectrometry, and thermogravimetric analysis and compared with an as-synthesized cobalt-based framework. Co-TPA/TA demonstrated good antimicrobial efficiency under optimum conditions against yeast Candida albicans ATCC 10231, Gram-negative Escherichia coli ATCC 8739, and Gram-positive Staphylococcus aureus ATCC 6538 with an inhibition zone ranging from 14 to 20 mm. Reduced ATP levels, generation of reactive oxygen species, membrane damage from cobalt ion release, and development of an alkaline microenvironment could all be contributing factors to the possible antimicrobial pathways. The novel framework can be obtained using simple, affordable, and easily accessible commercial ligands and is considered to have the potential to be used as an antimicrobial material in the future.

Cobalt MOF-Based Porous Carbonaceous Spheres for Multimodal Soft Actuator Exhibiting Intricate Biomimetic Motions.

The advancement ofactive electrodematerialsisessentialtomeetthe demand for multifaceted soft robotic interactions.Inthisstudy, a new type of porous carbonaceous sphere (PCS) for a multimodal soft actuator capable of both magnetoactive and electro-ionic responses is reported. The PCS, derived from the simultaneous oxidative and reductive breakdown of specially designed cobalt-based metal-organic frameworks (Co-MOFs) with varying metal-to-ligand ratios, exhibits a high specific surface area of 529 m2 g-1 and a saturated magnetization of 142.7 Am2 kg-1. The size of the PCS can be controlled through the Ostwald ripening mechanism, while the porous structure can be regulated by adjusting the metal-to-ligand mol ratio. Its exceptional compatibility with poly(3,4-ethylene-dioxythiophene)-poly(styrenesulfonate)enables the creation of uniform electrode, crucial for producing soft actuators that work in both magnetic and electrical fields. Operated at an ultralow voltage of 1V, the PCS-based actuator generates a blocking force of 47.5 mN and exhibits significant bending deflection even at an oscillation frequency of 10Hz. Employing this simultaneous multimodal actuation ensures the dynamic and complex motions of a balancing bird robot and a dynamic eagle robot. This advancement marks a significant step toward the realization of more dynamic and versatile soft robotic systems.

Cobalt-based metal–organic framework (Co-MOF) thin films with high capacitance for supercapacitor electrode

Cobalt-based metal–organic framework (Co-MOF) thin films with high capacitance for supercapacitor electrode

Crystal engineering of bimetallic cobalt-based metal–organic framework nanosheets for high-performance aqueous rechargeable cobalt-zinc batteries

Aqueous rechargeable Zn-based batteries (ARZBs) have attracted increasing attention as favorable candidates for energy storage systems due to their high security, environmental friendliness, and abundance of electrode materials. At present, the most widely reported materials used in cobalt-zinc (Co-Zn) batteries are cobalt-based oxides and their derivatives, however, they still exhibit low actual capacities and unsatisfactory cycle lives. Metal-organic frameworks (MOFs), as a new class of porous materials with high specific surface area and adjustable pore size, have attracted considerable attention in the field of energy storage. Currently, pristine MOFs have currently few applications in Co-Zn batteries, and their performance is not ideal. Herein, we report a series of two-dimensional (2D) bimetallic CoM-MOF (M = Ni, Mn, Mg and Cu) nanosheets based on trimesic acid (H3BTC) ligand as cathodes for alkaline Co-Zn batteries via a simple one-pot hydrothermal synthesis. Among the synthesized MOFs, the CoNi-MOF nanosheets have the best performance, exhibiting a high reversible capacity of 344 mA h g−1 and demonstrating a good cycling life with 90 % capacity retention at 20 A g−1 after 1500 cycles. The energy storage mechanism is studied through a series of ex-situ characterizations. This study is of great importance in advancing the application of 2D pristine MOFs for high-performance Co-Zn batteries.

Effect of synthesis temperature on the structural morphology of a metal–organic framework and the capacitor performance of derived cobalt–nickel layered double hydroxides

Three-dimensional interconnected nickel–cobalt layered double hydroxides (NiCo-LDHs) were prepared on nickel foam by ion exchange using a cobalt-based metal–organic framework (Co-MOF) as a template at different temperatures. The effects of the Co-MOF preparation temperature on the growth, mass, morphology, and electrochemical properties of the Co-MOF and derived NiCo-LDH samples were studied. The synthesis temperature from 30 to 50 °C gradually increased the mass of the active material and the thickness of the Co-MOF sheets grown on the nickel foam. The higher the temperature is, the larger the proportion of Co3+. β-Cobalt hydroxide (β-Co(OH)2) sheets were generated above 60 °C. The morphology and mass loading pattern of the derived flocculent layer clusters of NiCo-LDH were inherited from metal-organic frameworks (MOFs). The areal capacitance of NiCo-LDH shows an inverted U-shaped curve trend with increasing temperature. The electrode material synthesized at 50 °C had a tremendous specific capacitance of 7631 mF·cm−2 at a current density of 2 mA·cm−2. The asymmetric supercapacitor assembled with the sample and active carbon (AC) achieved an energy density of 55.0 Wh·kg−1 at a power density of 800.0 W·kg−1, demonstrating the great potential of the NiCo-LDH material for energy storage. This work presents a new strategy for designing and fabricating advanced green supercapacitor materials with large power and energy densities.

An eco-friendly self-assembled catalyst preparation and study of tetracycline degradation: Performance, mechanism to application

Chloromethyl styrene resin can undergo specific chemical modifications and is an excellent adsorbent material for treating difficult-to-degrade substances in wastewater. In this study, chloromethyl styrene resin will be used as a carrier, and polystyrene chloromethyl resin (PS-Cl) was converted into PS-NH2 by amino modification. The self-assembly of cobalt-based metal–organic framework (CoMOF) was induced on the surface of PS-NH2 by using a novel preparation technique. The performance of the prepared PS-NH2@CoMOF self-assembled catalysts with core–shell-like structures in degrading the target pollutant, tetracycline (TC), was evaluated. The catalysts effectively induced rapid OH radical production from H2O2, had a degradation rate of as high as 88.3 % for 20 mg/L TC solution, and were highly stable and adaptable to aqueous environments. Free radicals and intermediates in the catalytic degradation process were detected by electron paramagnetic resonance and high-performance liquid chromatography mass spectrometry, and possible catalytic degradation pathways were analyzed. The catalytic dissociation behavior of H2O2 in the presence of different catalysts was studied in depth and compared with that of similar metal–organic framework materials through density-functional theory calculations. Results demonstrated the excellent performance of the PS-NH2@CoMOF catalysts. Finally, the catalysts' potential for use in practical engineering applications was evaluated with a flow column experimental model, and the results were more than satisfactory. Therefore, the use of the catalysts to degrade TC has great potential.

Sulfonated Cobalt Metal-Organic Framework Embedded Mixed Matrix Membrane towards Fuel-Cell Applications.

New strategies for enhancement of the fuel-cell performance of a poly(2,5-benzimidazole) (ABPBI) membrane loaded with a functionalized cobalt-based metal-organic framework (MOF) for H2-O2 fuel cells. ABPBI was prepared using the polycondensation method, and various proportions of sulfonated cobalt MOF (sCo-MOF) were incorporated into ABPBI to fabricate a proton-exchange membrane (PEM). Later, the fabricated membranes were soaked in 1 M sulfuric acid to produce sulfonated PEMs. The developed composite membranes had increased proton conductivity, tensile strength, physicochemical properties, and fuel-cell performance compared to the sulfonated ABPBI (sABPBI) membrane. A membrane embedded with 4 wt % sCo-MOF shows higher water uptake and ion-exchange capacity values of 23.25% and 2.89 mequiv g-1, respectively. The membrane electrode assemblies were fabricated to perform unit-cell tests for both sABPBI and 4 wt % sCo-MOF/sABPBI membranes. The 4 wt % sCo-MOF-loaded sABPBI membrane demonstrated good unit-cell performance in the fuel-cell test, with a power density of 415.8 mW cm-2 at 80 °C, superior to the pristine sABPBI membrane's power density of 178.6 mW cm-2.

Enhanced charge separation and hole injection of Ti–Fe2O3 photoanode by ultrathin CoCu-MOFs for efficient photoelectrochemical water oxidation

Cobalt-based metal-organic frameworks (Co-MOFs) are considered excellent cocatalysts for improving the photoelectrochemical performance of photoanodes. Considering the boundedness of monometallic MOFs, introducing a second metal is an efficient method to enhance the activity and stability of Co-MOFs. In this work, Cu doped Co-MOFs was successfully decorated on Ti–Fe2O3 to prepare Ti–Fe2O3/CoCu-MOF. The photocurrent density of composite photoanode at 1.23 V vs. RHE reaches 2.06 mA/cm2, 5.5 times higher than that of Ti–Fe2O3, and the onset potential shifts 170 mV negatively. The results showed that CoCu-MOFs thin layer not only provided abundant active sites, but also effectively passivated the acceptor surface states of Ti–Fe2O3, thus inhibiting surface charge recombination. In addition, the introduction of Cu2+ can induce the generation of higher valence Co species, which significantly promotes the transfer of holes from Ti–Fe2O3 to the electrolyte. Our work demonstrates a new and promising photoelectrochemical cocatalyst, and provides a convenient method for the construction of other bimetallic MOFs materials.

Elaboration of a green and highly dispersible Co-MOFs induced Co-doped C3N5 photocatalyst: Applications and mechanistic insights into activated perxymonosulfate degradation of antibiotics

In recent years, metal-organic frameworks (MOFs) as metal-based carbon materials have been widely concerned with the application of activated perxymonosulfate(PMS) to degrade antibiotics. However, constructing MOFs-derived materials with excellent dispersion, highly exposed metal active sites, and environmental friendliness remains a challenge. This paper reports for the first time the in-situ formation of nitrogen-rich Co-doped C3N5 (Co-C3N5) materials using a cobalt-based metal-organic framework (Co-MOFs), which has highly dispersed metal sites that are conducive to the activation of PMS. The forbidden bandwidth value of Co-C3N5 photocatalyst is as low as ∼1.20 eV, which could completely degrade chlortetracycline hydrochloride (CTC) with the initial concentration of 30 mg/L within 6 min under a light source of 50 W LED lamp. The results indicate that efficient photoelectron separation and transport are key factors in the activation and degradation of CTC by PMS, involving both free radical and non-free radical degradation processes. Meanwhile, the skeletal structure of MOFs and the triazine ring of C3N5 were retained, enhancing the stability of the photocatalyst and reducing the leaching of cobalt Finally, the seed germination experiment of Chinese cabbage showed that the treated CTC could increase the root length of Chinese cabbage seedlings by 10.1∼42.9%, which proved that the materials had no toxic effect on environment and could provide carbon and nitrogen source for plant growth. Based on this, this study proposes a novel approach for the development of MOFs-derived carbon photocatalysts that exhibit excellent dispersion and highly exposed metal active sites.

Sulfide-based MOF material modification of separators: enhancing performance of lithium-sulfur batteries by suppressing shuttle effect

ABSTRACT Lithium-sulfur batteries (LSBs) are extensively studied owing to their high theoretical capacity and low cost. However, the shuttle effect of lithium-sulfur batteries hinders their development. In this study, we obtained a modified separator to inhibit the shuttle effect through physical and chemical adsorption. The CoS2 nanosheets (CSNS) derived from a cobalt-based metal-organic framework (Co-MOF) were synthesized by a simple two-step method involving hydrothermal sulfurization and thermal decomposition. The material was then coated onto a Polypropylene (PP) separator using vacuum filtration and assembled into a LSB for systematic testing and research of its electrochemical performance and mechanism. Thanks to the intrinsic polarity of the CSNs and more active sites brought by the Co-MOF material, the modified separator has strong chemical adsorption and catalytic effects on polysulfides, anchoring and accelerating their conversion. When using the CSNs-PP separator, the LSB achieved a high initial capacity of 1002.4 mAh g−1 at 1 C, with only a 0.099% decay per cycle after 500 cycles. The modified separator effectively alleviating the shuttle effect, reducing internal resistance, weakening reaction polarization, and improving the specific capacity, stability, and reversibility of the battery.

Ultrafine Iridium Nanoparticles Anchored on Co-Based Metal-Organic Framework Nanosheets for Robust Hydrogen Evolution in Alkaline Media.

A highly promising electrocatalyst has been designed and prepared for the hydrogen evolution reaction (HER). This involves incorporating well-dispersed Ir nanoparticles into a cobalt-based metal-organic framework known as Co-BPDC [Co(bpdc)(H2O)2, BPDC: 4,4'-biphenyldicarboxylic acid]. Ir@Co-BPDC demonstrates exceptional HER activity in alkaline media, surpassing both commercial Pt/C and recent noble-metal catalysts. Theoretical results indicate that electron redistribution, induced by interfacial bonds, optimizes the adsorption energy of water and hydrogen, thereby enhancing our understanding of the superior properties of Ir@Co-BPDC for HER.

Epoxy coating containing CoMOF@MBT metal-organic framework for active protection of aluminum alloy

A new cobalt-based metal-organic framework (CoMOF) was synthesized and subjected to comprehensive characterization employing a range of established techniques including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and thermal analyses. CoMOF was functionalized by loading mercaptobenzothiazole (MBT) onto CoMOF to fabricate CoMOF@MBT with anticorrosion properties. Polarization and immersion tests were employed to estimate the corrosion inhibition ability of CoMOF@MBT in NaCl medium. The results show that it inhibits corrosion of AA2024-T3 aluminum alloy when it is submerged in a NaCl solution with a pH of 3, yielding an inhibition efficiency of 87 %. Protective anticorrosion coatings were prepared by incorporating CoMOF@MBT particles into epoxy resin and coated on AA 2024-T3 substrate. Corrosion resistance of the protective coatings was assessed through the utilization of EIS and salt spray tests and the results show that scratched panels with coating containing CoMOF@MBT exhibit a slow decline in Rct values. It shows an Rct value of 1.45 × 104 Ω cm2 after 48 h of immersion in NaCl medium. The results demonstrated that incorporating CoMOF@MBT improves the capacity of epoxy coatings to withstand corrosion of AA2024-T3 panels in NaCl through the smart release of MBT molecules upon exposure to corrosive agents.

A Co and Fe bimetallic MOF with enhanced electrocatalytic oxygen evolution performance: exploring the electronic environment modifications upon Fe incorporation

The incorporation of iron into the cobalt-based metal–organic framework modifies the electronic environment and the resulting bimetallic MOF exhibits enhanced oxygen evolution reaction performance.

Elucidating the redox activity of cobalt-1,2,3,4-cyclopentane-tetracarboxylic acid and 1,2,4,5-benzene-tetracarboxylic acid-based metal-organic frameworks for a hybrid supercapacitor.

The development of electrode materials with extraordinary energy densities or high power densities has experienced a spectacular upsurge because of significant advances in energy storage technology. In recent years, the family of metal-organic frameworks (MOFs) has become an essential contender for electrode materials. Herein, two cobalt-based MOFs are synthesized with distinct linkers named 1,2,4,5-benzene-tetra-carboxylic acid (BTCA) and 1,2,3,4-cyclopentane-tetracarboxylic acid (CPTC). Investigations have been rigorously conducted to fully understand the effect of linkers on the electrochemical properties of Co-based MOFs. The best sample among the MOFs was used with activated carbon to create a battery-supercapacitor hybrid device. Due to its noteworthy results, specific capacity (100.3 C g-1), energy density (23 W h kg-1), power density (3400 W kg-1) and with the lowest ESR value of 0.4 Ω as well as its 95.4% capacity retention, the fabricated hybrid device was discovered to be very appealing for applications demanding energy storage. An approach for evaluating battery-supercapacitors was employed by quantifying the capacitive and diffusive contributions using Dunn's model to reflect the bulk and surface processes occurring during charge storage. This study fills the gap between supercapacitors and batteries, as well as providing a roadmap for creating a new generation of energy storage technologies with improved features.

Cobalt-based metal–organic framework for desulfurization of thiophene as a model fuel

Increased energy consumption from continued economic expansion generates environmental challenges and health hazards from burning fuel containing sulfur compounds. We explore the effectiveness of a cobalt-based MOF, BITSH-1, as an adsorbent to remove thiophene from model fuel.

A stable paddle-wheel Co-MOF (FNU-2) for the efficient separation of light hydrocarbons

The separation of methane from higher hydrocarbons (C2–C3) in natural gas processing is a crucial and energy-intensive operation. This work presents a comprehensive study on the separation of propane and ethane from methane using cobalt-based metal-organic frameworks (FNU-2), which exhibit exceptional stability and selectivity and preferential adsorption towards C2–C3 hydrocarbons. The selectivity values of C2H6/CH4 and C3H8/CH4 calculated by IAST are 43.9 and 638.9, respectively. According to theoretical calculations, the Van der Waals interactions of guest molecules play crucial roles in influencing the separation performance. Moreover, dynamic breakthrough experiments have revealed the promising potential of this adsorbent in industrial separations. These experiments indicate that the adsorbent is highly suitable for effectively separating and purifying natural gas. This study overall presents a novel and efficient adsorbent that can be employed to separate and purify natural gas in various industrial applications.