Co-based Metal-organic Framework Research Articles

Highly efficient Hg2+ removal via a competitive strategy using a Co-based metal organic framework ZIF-67

The stronger coordination ability of mercury ions with organic ligands than the metal ions in metal organic framework (MOFs) provides an accessible way to separate mercury ions from solution using specific MOFs. In this study, a Co-based MOF (ZIF-67, Co(mIM)2) was synthesized. It did not introduce specific functional groups, such as -SH and -NH2, into its structure through complicated steps. It separate Hg2+ from wastewater with a new strategy, which utilized the stronger coordination ability of Hg2+ with the nitrogen atom on the imidazole ring of the organic ligand than the Co2+ ions. Hg2+ replaced Co2+ nodes from ZIF-67 and formed a more stable precipitate with mIM. The experimental results showed that this new strategy was efficient. ZIF-67 exhibited Hg2+ adsorption capacity of 1740 mg/g, much higher than the known MOFs sorbents. mIMs is the reaction center and ZIF-67 can improve its utilization. The sample color faded from purple to white due to the loss of cobalt ion. It is a great feature of ZIF-67 that allows users to judge whether the sorbent is deactivated intuitively. ZIF-67 can be sustainable recycled by adding organic ligands to the solution after treatment due to its simple synthesis method at room temperature. It's a high-efficient and sustainable sorbent for Hg2+ separation from wastewater.

Direct growth and post-treatment of zeolitic imidazolate framework-67 on carbon paper: an effective and stable electrode system for electrocatalytic reactions

Co-based MOFs are directly grown using an electrodeposited layer of Co(OH)2 on carbon paper and converted to cobalt sulfide (CoxSy) through a post-treatment process. The final electrode system exhibits remarkable oxygen evolution reaction performance.

MOF sensors for food safety: ultralow detection of putrescine and cadaverine in protein rich foods

Two Co-based fluorescent MOFs are reported to detect biogenic amines in protein rich foods like fish and cheese.

Conductive Co-based metal organic framework nanostructures for excellent potassium- and lithium-ion storage: kinetics and mechanism studies

Nanostructured Co-CAT metal–organic frameworks show excellent potassium storage performance in terms of high specific capacity, fast charge/discharge and long term storage stability.

Iron-doped novel Co-based metal-organic frameworks for preparation of bifunctional catalysts with an amorphous structure for OER/HER in alkaline solution.

A novel two-dimensional Co-MOF material {[Co(dptz)2(oba)2]·(DMF)2}n is prepared using mixed organic ligands, which exhibits both OER (oxygen evolution reaction) and HER (hydrogen evolution reaction) catalytic performance. The integration of an Fe dopant and amorphous interface into Co-MOF to improving the electrocatalytic performance of pristine MOFs (metal-organic frameworks) is demonstrated and the origin of the remarkable electrocatalytic performance of the catalyst is elucidated. The comprehensive characterization data of Fe@Co-MOFs illustrate that there is a crystallinity transition during the doping of Co-MOF, which increases the electron transfer rate of the material and ensures increased exposure of the ligand unsaturated active site on the surface, and modulates the electronic structure of the Co center in a synergistic manner. As a result, the optimized catalytic Fe@Co-MOF-3 with an amorphous structure exhibits outstanding electrocatalytic performance for the OER, with only 248 mV at a current density of 50 mA cm-2 and excellent stability after 11 h of testing in alkaline solution. Not only that, the HER was achieved with a low overpotential of 150 mV at 10 mA cm-2. The present work indicates that the as-synthesized Co-MOF and Fe@Co-MOFs offer prospects in developing electrocatalysts for water splitting.

“One-for-Two” Strategy: The Consturction of High Performance Positive and Negative Electrode Materials Via One Co-Based Metal Organic Framework Precursor for Boosted Hybrid Supercapacitor Energy Density

“One-for-Two” Strategy: The Consturction of High Performance Positive and Negative Electrode Materials Via One Co-Based Metal Organic Framework Precursor for Boosted Hybrid Supercapacitor Energy Density

Co-based metal-organic framework for photocatalytic hydrogen generation.

Hydrogen production through an artificial photocatalytic process in the solar light region using a water-stable Co-Tz (Tz = 1,2,4-triazolate) framework was demonstrated. Possessing such a high photostability and highly reactive sites at the tetrahedral cobalt centers, Co-Tz exhibits a great photocatalytic performance converting water into hydrogen of 9.32 mmol g-1 at 4 h in the presence of fluorescein (FI) and triethylamine (TEA) as a photosensitizer and sacrificial agent, respectively. In addition, the framework is reusable without losing its catalytical integrity.

Efficient Metal-Oriented Electrodeposition of Co-Based Metal-Organic Framework with Superior Capacitive Performance

Efficient Metal-Oriented Electrodeposition of Co-Based Metal-Organic Framework with Superior Capacitive Performance

Recent progress in Co–based metal–organic framework derivatives for advanced batteries

• This review summarizes Co-based MOF derivatives for battery applications. • The relationship between synthetic strategies and performances has been discussed. • Main challenges and reasonable solutions for commercialization are proposed. To date, Co–based metal–organic frameworks (Co–MOFs) have drawn much attention owing to their advantages of easy preparation, high porosity and adjustable structure. Because of these enticing properties, numerous efforts have been devoted to their applications in energy storage and conversion. However, poor conductivity has become one of the biggest obstacles for large–scale use of pristine Co–MOFs. Subsequently, many attempts have been carried out to develop various Co–MOF derived materials as electrodes for rechargeable batteries in order to address the above–mentioned shortcoming and to enhance the electrical conductivity with improved stability during cycling. Moreover, in addition to improvement of Li–ion batteries in practical utilization, seeking for other rechargeable batteries is another urgent task due to the high cost and limited sources of metallic Li. Herein, by following the recent research progress, this review provides an overview of applications of Co–MOF derived materials in various rechargeable batteries including lithium–ion batteries, sodium–ion batteries, lithium–sulfur batteries, zinc air batteries and other rechargeable batteries, where they have been utilized as cathodes, anodes, separators and electrocatalysts. Accordingly, we categorize and compare the morphology driven electrochemical performance of various Co–MOF derivatives including porous carbon, cobalt oxides, cobalt chalcogenides, cobalt phosphides and corresponding composites. Finally, current challenges for large–scale production and commercialization of Co–MOF derived materials as well as some reasonable solutions have been discussed at the end.

The role of supramolecular interactions and pyridine groups in the (photo)electrocatalytic properties of a non-precious Co-based MOF

The coordination of the functional groups is a useful parameter to control the electronic density of linkers, thus decreasing the HOMO orbital energy and generating lower energetic bandgaps.

Preparation of CoNi@CN composites based on metal-organic framework materials as high efficiency counter electrode materials for dye-sensitized solar cells

In this paper, Co-based metal organic framework mixtures (MOFs) stuff are used as self-sustain templates to prepare CoNi alloys and N-codop porous carbon composites (CoNi@CN) by one-step calcination and ion exchange methods and apply to the study of the counter electrode (CE) of dye-sensitized solar cells (DSSCs). CoNi@CN retains a large specific surface area, high porosity and abundant unsaturated sites of MOFs, and the conductivity and catalytic activity of porous carbon are improved by the introduction of CoNi alloy and N. At the same time, the nitrogen-doped porous carbon protects the CoNi alloy from corrosion of the electrolyte and ensures the stability of the material. CoNi@CN is used in DSSCs for catalytic reduction of I3- exhibits the photoelectric conversion efficiency of 8.85%, that is overtop the exhibited by Pt CE under the equal conditions. Therefore, CoNi@CN composites are prepared based on MOFs are expected to instead of Pt as DSSCs CE materials because of their excellent optoelectronic properties and inexpensive.

Metal-organic frameworks-derived Mn-doped Co3O4 porous nanosheets and enhanced CO sensing performance

Improving the gas-sensing performances of p-type oxide semiconductors is an important research issue. Here, we reported the simple fabrication of bare Co3O4 and Mn-doped Co3O4 porous nanosheets by annealing the Co-based metal-organic frameworks (MOFs) nanosheets precursors synthesized from the ion-assisted solvothermal treatment. Different characterization techniques were adopted to verify the physical and chemical morphologies of the as-prepared samples. The results demonstrate that Mn cations have been successfully doped into the lattice of Co3O4. Besides, these prepared samples were used for detection of carbon monoxide (CO). Results show that 3 mol% Mn-doped Co3O4 nanosheets present enhanced CO-sensing properties [(Rg − Ra)/Ra = 280% to 40 ppm at 125 °C] compared with bare Co3O4 nanosheets. The response reported here for the detection of CO even exceeds those of some n-type oxides under the same conditions. We speculate that the enhanced CO-sensing properties are probably due to the high specific surface area, abundant oxygen vacancies generated by Mn doping, and the relatively high Co3+/Co2+ ratio. The Mn-doped Co3O4 sensor has a huge potential advantage in detecting low concentrations of CO.

Progress in non-noble metal oxygen reduction electrocatalysts based on MOFs

<p indent=0mm>Proton exchange membrane fuel cells (PEMFCs) are favored in the field of new energy vehicles because of their cleanliness, high efficiency, quietness, high power density, low operating temperature, fast start-up and power matching. With the realization of mass production of fuel cell vehicles in many countries in the world in recent years, its large-scale promotion is imperative. However, the PEMFC cathode uses a high-load platinum (Pt)-based catalyst, which has greatly hindered the commercialization of fuel cell vehicles because of high cost. Pt is the most effective electrocatalyst for the low-temperature fuel cell cathode oxygen reduction reaction (ORR). On one hand, it can greatly reduce the amount of Pt through alloying and single-atom layer design. On the other hand, it can develop alternative high-activity and high-stability non-noble metals. The catalyst process is considered the ultimate solution. Among the many types of non-noble metal catalysts, the ORR activity and lifetime of the carbon-nitrogen-transition metal series non-noble metal catalysts are particularly worthy of attention. Non-precious metal ORR electrocatalysts based on metal organic framework materials (MOFs) have been extensively studied for their excellent properties. This paper introduces the characteristics and advantages of MOFs materials in detail and reviews the research status of carbon-nitrogen-transition metal ORR electrocatalysts based on MOFs materials at home and abroad in recent years, including Fe-based MOFs catalysts, Co-based MOFs catalysts, and bimetal MOFs catalysts. It also analyzes and forecasts the bottlenecks and challenges encountered in the research. In the future, we need to conduct in-depth research on the activity and stability of membrane electrodes.

Co-based metal-organic framework with phosphonate and triazole structures for enhancing fire retardancy of epoxy resin

A phosphonate and triazole containing binary carboxylic acid ligand was synthesized via azide-alkyne “click” reaction, which was further coordinated with cobalt nodes to form metal-organic framework (MOF) containing two important fire retardant elements, phosphorus and nitrogen (PN-MOF). With the loading of 6 wt% PN-MOF in epoxy resin (EP), the peak heat release rate, average heat release rate, total heat release, and total smoke production of EP/PN-MOF composites dramatically decreased by 44.6%, 52.9%, 44.0% and 36.2%, respectively. Meanwhile, the limiting oxygen index increased from 24.3% to 29.8%. Thanks to the excellent catalytic activity of PN-MOF in carbonation and oxidation, the release of toxic gasses from the composites was significantly reduced, particularly, the production of CO was decreased by 48% in comparison with neat EP. In addition, the glass transition temperature and modulus of EP/PN-MOF composites were increased, suggesting a strong interfacial interaction between PN-MOF and EP matrix. Overall, this research provides an efficient strategy for the preparation of MOF-type flame retardant to simultaneously enhance the flame retardancy and physical properties of polymeric materials.

Hydroxyapatite Coated with Co-Based Metal Organic Framework Nanoparticles as Heterojunctions for Catalytic Degradation of Organics

Hydroxyapatite Coated with Co-Based Metal Organic Framework Nanoparticles as Heterojunctions for Catalytic Degradation of Organics

Bioinspired nanozyme enabling glucometer readout for portable monitoring of pesticide under resource-scarce environments

Pesticide residual has always been a severe environmental issue due to its adverse effects on ecosystems. The development of user-friendly program is imperative for efficient monitoring and control of pesticides with respect to environmental protection. To this end, we herein report a bioinspired nanozyme enabling portable glucometer readout for assessing pesticide residual, based on an aptamer-switching approach. Notably, Co-based metal–organic framework (Co-MOF) decorated by aptamer is built, as a signal probe, for identifying acetamiprid (as a model analyte). Comparing with the enzyme-based methods, which works in pH 6 ∼ 7, our system has high stability and DNA hybridization efficiency beyond pH 8. By introducing completive binding between acetamiprid and MOF-aptamer into glucose consumption, this method exhibits a wide linear range (1 ∼ 200 nM) with a low limit of detection (0.42 nM, corresponding to 0.093 μg kg−1 by weight), well qualified for the regular monitoring of acetamiprid residue specified by World Health Organization. With virtues of portability, sensitivity and anti-interference, the glucometer-based protocol enables us to innovatively carry out pesticide monitoring in agricultural soil, water source and foodstuffs, thereby holding promise for environmental monitoring in home-style and in-field scenarios.

Metal-Organic Framework-Derived CoOx/Carbon Composite Array for High-Performance Supercapacitors.

Metal-organic frameworks (MOFs) and their derivatives are promising materials for energy conversion and storage. This study demonstrates a solvent-free method to fabricate a CoOx/carbon composite array derived from ZIF-67 for asymmetric supercapacitors. Tree-like Co metal arrays are electrodeposited on a surface and then directly converted into composite ZIF-67/Co-based MOF arrays via a chemical vapor deposition method (MOF-CVD). Finally, the CoOx/carbon composite array is obtained by regulated calcination of the ZIF-67/Co composite array. The as-prepared CoOx/carbon composite arrays provide a less tortuous pathway for ion diffusion, high pseudocapacitance from transition-metal oxides, and good electrical conductivity from carbon. Moreover, the absence of adhesives in array electrodes is also beneficial to the promotion of the electrochemical performance. The as-fabricated CoOx/carbon composite array electrode shows excellent electrochemical performance with high energy density, high power density, superior rate capability, and long cycle life in an asymmetric supercapacitor. These MOF-derived composite arrays are promising candidate materials for power sources because of their good electrochemical performance.

Influence of Co-MOF morphological modulation on its electrochemical performance

The direct use of the original metal-organic framework (MOF) as an electrode material can reduce energy consumption and save costs during the commercialization of MOF-based energy storage materials. In this work, three kinds of ammonium solutions with different anions are introduced in the synthesis process and three forms of Co-based MOFs with different appearances are obtained: Co-BTC block, where BTC is trimesic acid; Co-BTC block microspheres; and Co-BTC nanoblock microspheres (CTNBMs). The CTNBMs have the highest specific capacitance among the three, which reveals that the nanonization of MOFs can effectively improve their energy storage performance. The CTNBMs exhibit a specific capacitance of 427.8 F g−1 at 0.5 A g−1 with a capacitance retention of 73.5% at 10 A g−1. The energy storage mechanism shows that CTNBMs are affected mainly by diffusion control during the electrochemical process. Cyclic stability measurements demonstrate that the capacitance retention of CTNBMs after 3000 cycles at 8 A g−1 is 85.9%, which is the best of the three as-prepared materials. In addition, the assembled CTNBM//activated carbon asymmetric supercapacitor device has a maximum energy density of 30.6 W h kg−1 at a power density of 349.7 W kg−1.

Electrochemical Reduction of CO2: A Review of Cobalt Based Catalysts for Carbon Dioxide Conversion to Fuels.

Electrochemical CO2 reduction reaction (CO2RR) provides a promising approach to curbing harmful emissions contributing to global warming. However, several challenges hinder the commercialization of this technology, including high overpotentials, electrode instability, and low Faradic efficiencies of desirable products. Several materials have been developed to overcome these challenges. This mini-review discusses the recent performance of various cobalt (Co) electrocatalysts, including Co-single atom, Co-multi metals, Co-complexes, Co-based metal–organic frameworks (MOFs), Co-based covalent organic frameworks (COFs), Co-nitrides, and Co-oxides. These materials are reviewed with respect to their stability of facilitating CO2 conversion to valuable products, and a summary of the current literature is highlighted, along with future perspectives for the development of efficient CO2RR.

Metal-organic frameworks derived porous hollow Co/C microcubes with improved synergistic effect for high-efficiency microwave absorption

High-performance microwave absorption materials with strong absorption and thin thickness have increasingly become a reach hotspot. Here, we successfully prepared a novel porous hollow Co/C microcube by controlling the pyrolysis of the Co-based metal-organic frameworks (MOFs) precursor. The phase composition, microstructure, porosity, and magnetic properties were well modified by controlling the pyrolysis temperature. The multiple components (Co and C) and novel porous structure endowed Co/C microcubes with efficient microwave absorption. As expected, the porous hollow Co/C microcubes achieved enhanced microwave absorption with a strong reflection loss of −52.8 dB, a wide effective absorbing bandwidth of 4.5 GHz, and an ultra-thin thickness of 1.4 mm. It was found that the underlying microwave absorption mechanism was the dielectric loss stemmed from the interfacial polarization, magnetic loss caused by the magnetic resonance, and multiple reflections and scattering in the porous structure. Thus, this work can provide a facile method to develop the MOFs-derived porous hollow composites with high-efficiency microwave absorption performance.