Cobalt-based Metal-organic Framework Research Articles

Ammonia Decomposition via MOF-derived Photothermal Catalysts.

Three cobalt-based metal-organic framework (MOF)-derived catalysts were developed for photothermal hydrogen production via ammonia decomposition. The selected MOFs were from distinct families, featuring carboxylate and imidazole linkers, and diverse in terms of porosity. The resulting catalysts consisted of uniform and homogeneously dispersed cobalt nanoparticles embedded within a carbon matrix. The carboxylate-based MOF-74 derived catalyst showed the highest initial activity, but gradually deactivated. ZIF-67 derived catalyst, however, demonstrated stable performance. The synergy between photo and thermal effects was confirmed. Additionally, this catalyst was found to be also effective in ammonia synthesis, potentially closing the loop for sustainable ammonia utilization.

Research Progress of Cobalt-Based Metal Organic Frameworks and Their Derivatives in Energy Storage and Conversion

Research Progress of Cobalt-Based Metal Organic Frameworks and Their Derivatives in Energy Storage and Conversion

Enhanced electrochemical activity by NiCo-P nano-particles modified Co-MOF nanorods

The design and preparation of high-performance electrode materials are among the most extensively researched topics in supercapacitor studies. By combining the three-dimensional structure and compatibility of cobalt-based metal-organic framework (Co-MOF) with the high redox activity of metal phosphates, a green, efficient, and safe co-precipitation and electro-deposition strategy was employed to fabricate the Co-MOF@NiCo-P heterostructure composite electrode material, with NiCo-P nanoparticles uniformly decorated on the surface of Co-MOF, addressing the issues of limited conductivity of Co-MOF and the tendency of NiCo-P to aggregate when grown in situ on foam nickel. In a three-electrode system, the Co-MOF@NiCo-P electrode exhibits specific capacities of 1389.8 F g−1 at 1 A g−1 and 964.3 F g−1 at 20 A g−1. The assembled Co-MOF@NiCo-P//AC hybrid supercapacitor device demonstrates energy densities of 54.08 Wh kg−1 (22.92 Wh kg−1) and power densities of 825 W kg−1 (8250 W kg−1), showing promising application prospects. This research offers a novel method for developing high-performance electrode materials.

One-dimensional rare-earth La-MOFs coordinated with hexamethylenetetramine-Co MOFs derived highly efficient catalyst for cascade reaction of nitroarenes with alcohols☆

A composite metal-organic frameworks (MOFs) structure, designated as Co-hmta@La-salen, was synthesized through coordination interactions between a one-dimensional lanthanum MOFs (La-salen) with high density of uncoordinated imine (–CH=N–) groups and a cobalt-based MOFs (Co-hmta) structure prepared using hydrogen bonding stacking with hexamethylenetetramine (hmta) as the organic ligand. Subsequently, the Co-hmta@La-salen composite was chosen as a template for the pyrolysis process to synthesize a La(OH)3 supported metallic Co catalyst incorporating carbon-nitrogen (Co/La(OH)3-CN-hmta) catalyst. The catalytic results show that Co/La(OH)3-CN-hmta (54% and 46% selectivity for aniline and N-phenylbenzylamine, respectively) displays superior cascade performance compared to classic Co/La(OH)3-CN-nit catalyst (69% and 31% selectivity for aniline and N-phenylbenzylamine, respectively). Moreover, the kinetic test results indicate that N-alkylation is the rate-limiting step of the overall cascade reaction. The Co/La(OH)3-CN-hmta catalyst can be separated from the reaction system using a magnet, and it also exhibits good cyclic stability. All of these suggest that the “MOFs plus MOFs via coordination” templating method can be employed as an efficient strategy for the preparation of supported catalysts.

Ultrasensitive detection of hazardous gas at room temperature enabled by MOF@MXene 0D-2D heterostructure

Achieving high sensitivity in detecting trace concentrations of toxic gases, particularly under room temperature (RT) conditions, remains a significant challenge. Herein, a 0D-2D heterostructure that can detect ppb-level H2S at RT is proposed by self-assembling cobalt-based metal–organic framework (Co-MOF) on Ti3C2Tx MXene. Co-MOFs with high specific surface areas can capture and concentrate target gas molecules, enhancing host-guest interactions and thereby boosting the selectivity and sensitivity. MXene nanosheets with high conductivity enable rapid electron transport at heterointerface, hence efficiently accelerating the reaction kinetics. Thereby, the as-prepared chemiresistive gas sensor based on Co-MOF@MXene 0D–2D heterostructure possessed excellent sensitivity against interfering gases and delivered an excellent response value of 11.1 to 400 ppb H2S at RT. The judicious design of MOF@MXene heterostructure may spur advanced hybrid material systems for superior sensing applications.

Different FeS Concentrations for Encapsulating ZIF-67 Nanomaterials toward the Enhanced Oxidation Evolution Reaction.

Due to the slow kinetic nature of the oxygen evolution reaction (OER), the development of electrocatalysts with high efficiency, stability, and economy for oxygen production using metal-organic framework (MOF) materials is still a challenging research topic. In this work, we chose the different concentrations of FeS adsorption to encapsulate metal cobalt-based ZIF-67 MOF for preparing a series of electrocatalysts (ZIF1FeSx, x = 0.2, 0.5, 0.75, and 1), which were mainly explored for the electrocatalytic OER. Among them, ZIF1FeS0.5 has excellent electrocatalytic activity for OER, which can be driven by low overpotentials of 276 and 349 mV at 10 and 50 mA cm-2 current densities, and more than 92% of the initial overpotential can be maintained after 100 h of continuous OER at 10 mA cm-2 current density. This is mainly due to the electronic interactions between the cobalt-based MOF and the FeS, which shift the electronic state of the active metal center to a higher valence state for increasing the number of active sites and enhancing the efficiency of electron transfer to facilitate the OER course. This work may contribute to the design of effective catalysts for the OER during the electrolysis of alkaline solutions.

Synergistic effect of Co-MOF/epoxy modified tannic acid/ammonium polyphosphate on flame retardancy, anti-melt dripping and mechanical properties of polylactic acid

Achieving flame retardancy and anti-dripping properties in polylactic acid (PLA) while preserving its mechanical integrity remains a significant challenge. In this study, a novel organic ligand rich in phosphorus (P) and nitrogen (N) was synthesized and coordinated with Co2+ions to form a cobalt-based metal–organic framework (Co-MOF) with a multilayer mesoporous structure, acting as an effective carbonization agent. This Co-MOF was then compounded with epoxy-modified tannic acid (eTA) and ammonium polyphosphate (APP) to create a synergistic flame-retardant system for PLA (PLA/MAT). The Co-MOF provides numerous active sites for catalytic oxidation, promoting the formation of a uniform, hill-like expanded carbon layer. During pyrolysis, the Co-MOF and APP yield cobalt oxides and polyphosphates, which catalyze the dehydration of PLA and eTA, facilitating carbonization and forming a continuous, dense protective layer. Consequently, the PLA/MAT system exhibits both robust mechanical properties and excellent flame retardancy, as demonstrated by a limiting oxygen index (LOI) of 27.0 % and a UL-94 V-0 rating, with no melt dripping observed during combustion tests. This work offers a novel approach for enhancing the flame retardancy and anti-dripping performance of PLA, with potential applications in engineering, electronics, and the automotive industry.

Co-doped Ni-PBA anchored on optimized ZIF-67-derived Co/N-doped hollow carbon framework for high-performance hybrid capacitive deionization

Prussian blue analogues (PBAs) are considered to be a promising electrode material for hybrid capacitive deionization (HCDI) due to their open lattice structure, adjustable composition and high theoretical capacity. Nevertheless, the performance of PBAs in practical applications is limited by their low intrinsic conductivity and structural degradation. Herein, we demonstrate an advanced heterostructure CoNi-PBA@Co/N-HC by anchoring cobalt-doped nickel hexacyanoferrate (CoNi-PBA) on cobalt/nitrogen-doped hollow porous carbon (Co/N-HC) derived from cobalt-based metal–organic frameworks (ZIF-67). Co/N-HC as the conductive growth framework of CoNi-PBA can not only promote the rapid charge transfer and efficient ion diffusion, but also mitigate the structural degradation of CoNi-PBA crystals during ion intercalation/deintercalation. Moreover, the doped Co in CoNi-PBA is derived from Co/N-HC, allowing the heterostructures to form more stable and tighter interconnections. Therefore, the optimal PBA@Co/N-HC300 electrode exhibits reduced equivalent series resistance (Rs 1.10 Ω < Rs (PBA) 1.41 Ω), enhanced ion diffusion rate (DNa+ 2.86 × 10−16 > DNa+(PBA) 4.65 × 10−18) and exceptional electrochemical stability (99 % capacitance retention, 500 times CV tests). Correspondingly, the HCDI cell PBA@Co/N-HC300//Co/N-HC demonstrates good Na+ removal capacity (33.37 mg·g−1), excellent charge efficiency (83.65 %), diminished energy consumption (0.657 kWh kg−1-NaCl) and improved cycle stability (90.8 % capacity retention, 40 cycles).

Perovskite/cobalt-based metal-organic framework hybrid promotes hydrogen production from oilfield wastewater electrolysis

Hydrogen has been recognized as a new green energy source. However, in regions where fresh water is scarce, research on the use of complex water systems, such as seawater and oilfield wastewater, to produce hydrogen by electrolysis instead of fresh water has become a pressing issue. In this paper, a low-cost and easy-to-synthesized hybrid catalyst composed of perovskite oxide SrCo0.7Fe0.3O3-δ (SCF) and cobalt-based metal-organic framework (Co-MOF) were synthesized using a simple and feasible in-situ coprecipitation method and exhibited excellent hydrogen evolution reaction (HER) activity in oilfield wastewater. The improvement of activity can be attributed to the synergistic effect between the two materials, which have more concentration of oxygen vacancies and more HER active sites due to Co ion migration. This work provides a practical approach to enhance HER activity in complex water systems by constructing spatial composite structures.

Formation of interior hollow nanocubes derived from cobalt-based metal-organic frameworks via one-step etching for efficient battery desalination

Battery desalination (BD) offers a sustainable solution for simultaneous energy storage and desalination, addressing the global need for clean water access. However, current BD technologies require improvements in salt removal capacity, charge efficiency and energy consumption to become practical. In this study, we present a BD system utilizing interior hollow nanocubes derived from a cobalt-based zeolitic imidazolate framework (Co-TA HC) as the cathode and silver nanoparticle on reduced graphene oxide (Ag@rGO) as the anode. The regular and hollow nanocubes, with enhanced specific surface area and abundant redox active sites, are prepared via a simple one-step mild tannic acid (TA) etching process, holding great promise for scalable manufacturing. The unique structure of the Co-TA HC significantly shortens the diffusion length of the Na+ and enhances the sodium intercalation kinetics, as indicated by the galvanostatic intermittent titration technique. The optimal pairing of the Co-TA HC and Ag@rGO enables the full discharge with voltage window of 0–1.4 V in the BD system, achieving high volumetric salt adsorption capacity (SAC) of 102.3 mg cm−3 and gravimetric SAC of 143.2 mg g−1 with a current density of 100 mA g−1. This suggests that the practical application of BD systems is a tangible possibility and paves the way for scaling-up emerging desalination technologies.

Construction of black phosphorus/metal-organic framework composites for electrochemical detection of uric acid

The detection of uric acid (UA) concentration is of great significance for the prevention and treatment of related diseases. In this work, we used a static precipitation strategy to prepare a surface carbonized cobalt-based metal-organic frameworks (MOFs) composite black phosphorus nanosheets (BPNS) electrode material for electrochemical detection of UA. The results showed that the sensor had a linear detection range of UA concentration from 1 to 2000 μM in acetate buffer with pH=5.6. In addition, the sensor still maintains a peak current response of 91.9 % after one month, indicating its good stability and anti-interference performance. The enhancement of sensing performance is attributed to the fact that the composite material retains the excellent electronic transport properties of BPNS. At the same time, the composite of MOFs makes the specific surface area and porosity of the material increase, so that the stability of BPNS is significantly improved. This work will provide new ideas for the construction of stable and efficient UA electrochemical sensors.

Preparation of a Cobalt-Based Metal–Organic Framework and Its Application as a Synergistic Flame Retardant in Epoxy Resins

Preparation of a Cobalt-Based Metal–Organic Framework and Its Application as a Synergistic Flame Retardant in Epoxy Resins

Singlet oxygen dominant-activation by hollow structural cobalt-based MOF/peroxymonosulfate system for micropollutant removal

Despite the keen interest in potentially using the metal-organic framework (MOF) in advanced oxidation processes (AOPs), their application for environmental abatement and the corresponding degradation mechanisms have remained largely elusive. This study explores the use of cobalt-based MOF (CoMOF) for peroxymonosulfate (PMS) activation to remove tetracycline (TC) from water resources. Under optimal conditions, the given catalytic system could achieve a TC removal of 83.3%. Radical quenching tests and EPR analysis revealed that SO4•–, HO•, •O2−, and 1O2 could participate in the catalytic degradation, but the discernible removal mechanism was mainly ascribed to the nonradical pathway induced by 1O2. At only 5 mg/L of CoMOF, the performance of the catalytic system was superior to that of PMS alone for different types of micropollutants. The CoMOF/PMS system could also reliably deal with typical anions in water, such as Cl−, SO42−, HCO3−, and PO43−. The MOF catalyst could last for four cycles with a minor decrease in reactivity of ∼30%. However, the removal performance decreased markedly when aromatic natural organic matter (NOM) were present in the water bodies, and the effectiveness was lower in alkaline or acidic environments. Our work offers insights into the catalytic degradation of CoMOF/PMS applied in contaminated water remediation and serves as a baseline for fabricating an efficient MOF with enhanced catalytic performance and stability.

A two-dimensional cobalt-based metal–organic framework efficiently adsorbs Cr(VI) from wastewater

Metal-organic frameworks (MOFs) display multi-level pores and abundant adsorption sites, which can effectively adsorb Cr(VI) from wastewater. In this paper, x-ray single crystal diffraction analysis showed that both the N atom and two carboxyl groups in L2− of [Co(L)(H2O)2]n (1) (H2L = 3, 5-pyridinedicarboxylic acid) underwent coordination reactions with Co(II) in μ3-η1:η1:η1 fashion, giving rise to the formation of a two-dimensional structure. The nano adsorbent of 1 (2D-Co-MOF-N) with a particle diameter about 100 nm was successfully prepared by cell disruption method. The optimal conditions for 2D-Co-MOF-N to adsorb Cr(VI) from wastewater were observed at pH 6.5, T = 30 °C, and a dosage of 0.10 g/L, achieving a maximum adsorption capacity of 207.93 mg/g which was better than most MOFs adsorbents. The present of Cl−, NO3–, SO42−, and PO43− in wastewater inhibited the adsorption of Cr(VI) by 2D-Co-MOF-N due to competitive adsorption. Cycling experiments showed that 2D-Co-MOF-N exhibited admirable structural and performance stability, which could be deemed as a potential candidate for the removal toxic ions from actual wastewater.

Phosphate ions functionalized metal-organic framework-derived cobalt oxide with improved redox reactivity for high-performance alkaline aqueous Zn-ion batteries

Alkaline aqueous Zn/Co3O4 batteries (AZCBs) have captured significant attention within the field of scalable grid energy storage due to their high output voltage (>1.8 V), superior safety profile, and low manufacturing cost. Nevertheless, the intrinsic Co3O4 material experiences limitations in terms of low electronic conductivity and insufficient active sites, consequently constraining its electrochemical performance in AZCBs. To address this challenge, this investigation focuses on the use of phosphate ions functionalized Co3O4 (referred to as PCO) material derived from cobalt-based metal-organic frameworks (Co-MOFs) as a cathode electrode in AZCBs. Both theory calculations and experimental verification illustrate that the functionalization with phosphate ion enhances the active sites for electrochemical redox reactions and increases the electrical conductivity of intrinsic Co3O4. Consequently, a pouch cell configuration of PCO-2||Zn with the optimized PCO-2 sample as cathode exhibits a high capacity of 162.0 mAh g−1, a maximum energy density of 265.7 Wh kg−1, a maximum power density of 16.39 kW kg−1. Furthermore, excellent long-term stability is observed, with the capacity retention rate reaching 92.3 % over 5000 cycles at a high current density of 5 A g−1. Additionally, the constructed fibrous flexible solid-state device also demonstrates notable long-term stability, with a capacity retention of 96 % after 2000 cycles under a high current density of 10 mA cm−2, and performs well under different deformation statuses. This successful approach may hold potential for the exploration of other cathode materials, such as Mn or V-based compounds, which may exhibit high performance in aqueous zinc-based batteries.

Hierarchical mesoporous Co3O4@C-N nanostructure rods derived from a metal-organic framework as high-performance anode for lithium-ion battery

A uniform hierarchical mesoporous Co3O4@C-N nanostructure rods were in situ fabricated successfully by developing a facile one-step strategy. Cobalt-based metal organic framework [Co3(ndc)(HCOO)3(μ-OH)(H2O)]n with special Co chine constructed framework structure treated as a precursor directly pyrolyzed in a mixed atmosphere of argon and oxygen (95:5) at 500 °C for 2 h. According to the XRD pattern, SEM, TEM, EDS mapping images and XPS spectrum analysis, the well-defined hierarchical mesoporous Co3O4@C-N nanostructure rods showed pure Co3O4 phase, are assembled from a large number of core–shell structured Co3O4@C-N spherical particles with an ultrasmall and uniform size (∼8 nm) which were further connected by N doped carbon net to form nanostructure rods. Using as anode material for lithium-ion batteries, these hierarchical mesoporous Co3O4@C-N nanostructure rods exhibit excellent electrochemical performance with high reversible capacity, rate capability and good cycling stability. They maintained a reversible specific capacity of more than 1000 mAh/g at 100 mA/g, and the discharge specific capacities at the 5 current density of 0.1, 0.2, 0.5, 1, 2, and 5 A/g reached 1123, 1094, 1044, 979, 879 and 688 mAh/g, respectively.

Development and Characterization of a Tunable Metal-Organic Framework (MOF) for the Synthesis of a Rare Sugar D-Tagatose.

D-tagatose is a valuable rare sugar with potential health benefits such as antiobesity, low-calorie, prebiotic, and anticancer. However, its production is mainly depending on chemical or enzymatic catalysis. Herein, a cobalt-based metal-organic framework (MOF) was developed at room temperature in an aqueous system using a self-assembly method. The L-arabinose isomerase (L-AI) was immobilized into this unique MOF by an in situ encapsulation process. The morphology and structural aspects of the MOF preparations were characterized by different analytical techniques such as scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), confocal laser scanning microscopy (CLSM), Fourier transform infrared spectroscopy (FT-IR), and X-Ray diffraction (XRD). Moreover, thermogravimetric analysis (TGA) suggested the high thermal stability of the L-AI@MOF. Significantly, the immobilized catalyst exhibited enhanced catalytic efficiency (kcat/Km) of 3.22mM-1s-1 and improved turnover number (kcat) of 57.32s-1. The L-AI@MOF efficiently catalyzes the synthesis of D-tagatose from D-galactose up to the equilibrium level (~ 50%) of isomerization in heterogeneous catalysis. Interestingly, L-AI@MOF was found stable and reusable for more than five cycles without the requirement of additional metal ions during catalysis. Thus, L-AI stabilized in the MOF system demonstrated a higher catalytic activity and potential guidance for the sustainable synthesis of rare sugar D-tagatose.

Environmentally friendly synthesis of 2D Co-MOF for transformation of isochromans to isochromanones by activating O2

From the perspective of green chemistry and sustainable development, it is highly desirable to produce catalysts in an environmentally friendly manner and utilize them to activate O2 for converting cheap chemicals into value-added chemicals. In this work, we have synthesized two cobalt-based metal-organic frameworks (Co-MOFs) in ethanol, a non-toxic reaction medium, and used them to convert isochromans to isochromanones with O2 as an oxidant and needing no additives. The experimental results indicate that the two Co-MOFs exhibit a favorable catalytic performance, in which the 2D Co-MOF (1) possesses a higher catalytic activity than the 3D Co-MOF (2). This may be due to the enhanced catalytic site exposure and rapid substance, electron, and proton transfer within the 2D Co-MOF. Furthermore, the reaction mechanism analysis indicates that the catalytic process may involve a radical reaction pathway. This work serves as an invaluable interpretation for advancing alternative 2D Co-MOF for activating O2 in organic catalytic transformation.

Synthesis of nitrogen-doped amorphous carbon nanotubes from novel cobalt-based MOF precursors for improving potassium-ion storage capability

Amorphous carbon materials with sophisticated morphologies, variable carbon layer structures, abundant defects, and tunable porosities are favorable as anodes for potassium-ion batteries (PIBs). Synthesizing amorphous carbon materials typically involves the pyrolysis of carbonaceous precursors. Nonetheless, there is still a lack of studies focused on achieving multifaceted structural optimizations of amorphous carbon through precursor formulation. Herein, nitrogen-doped amorphous carbon nanotubes (NACNTs) are derived from a novel composite precursor of cobalt-based metal–organic framework (CMOF) and graphitic carbon nitride (g-CN). The addition of g-CN in the precursor optimizes the structure of amorphous carbon such as morphology, interlayer spacing, nitrogen doping, and porosity. As a result, NACNTs demonstrate significantly improved electrochemical performance. The specific capacities of NACNTs after cycling at current densities of 100 mA/g and 1000 mA/g increased by 194 % and 230 %, reaching 346.6 mAh/g and 211.8 mAh/g, respectively. Furthermore, the NACNTs anode is matched with an organic cathode for full-cell evaluation. The full-cell attains a high specific capacity of 106 mAh/gcathode at a current density of 100 mA/g, retaining 90.5 % of the specific capacity of the cathode half-cell. This study provides a valuable reference for multifaceted structural optimization of amorphous carbon to improve potassium-ion storage capability.

Constructing local nanomolecular trap in a scalable, low-cost, and ultramicroporous metal–organic framework for efficient capture of greenhouse gases SF6 and CO2

The capture of sulfur hexafluoride (SF6) and carbon dioxide (CO2) is an important but challenging task for reducing greenhouse gas emission and thereby diminishing negative impacts of global climate change. Herein, we integrated local nanomolecular traps into an inexpensive cobalt-based metal–organic framework (MOF, namely GNU-3) with suitable pore sizes and functional pore surfaces for capturing greenhouse gases. Activated GNU-3a showed good adsorption and separation properties for SF6 and CO2. Especially for SF6, GNU-3a displayed the high SF6/N2 (10:90, v/v) selectivity of 317.6 and SF6 uptake capacity of 2.63mmol/g at 298 K and 1.0 bar. Grand canonical Monte Carlo simulations and first-principles dispersion-corrected density functional theory calculations identified that gas molecules were favorably trapped in polyaromatic ring functionalized channel centers and nanomolecular traps of pore walls by the strong hydrogen bond interactions. Excellent breakthrough results recommend practical separating properties of GNU-3a for binary SF6/N2 and CO2/N2 mixtures, and ternary SF6/CO2/N2 mixtures. Moreover, benefitting from superior features of cheap raw materials and large-scale synthesis, GNU-3 is expected to be applied to practical industrial scenarios. This work may provide insights into constructing prospectively industrial porous MOF adsorbents with optimal pore structures for greenhouse gas capture.