The Atomic Structure and Mechanical Properties of ZIF-4 under High Pressure: Ab Initio Calculations

The effects of pressure on the structural and electronic properties and the ionic configuration of ZIF-4 were investigated through the first-principles method based on the density functional theory. The elastic properties, including the isotropic bulk modulus K, shear modulus G, Young's modulus E, and Poisson's ratio ν of the orthorhombic-type structure ZIF-4 were determined using the Voigt-Reuss-Hill averaging scheme. The results show that the ZIF-4 phase is ductile according to the analysis of K/G and Cauchy pressure. The Debye temperatures obtained from the elastic stiffness constants increase with increasing pressure. Finally, the pressure-dependent behaviors of the density of states and ionic configuration are successfully calculated and discussed.

Solvent-Free Hydrogenation of 5-Hydroxymethylfurfural and Furfural to Furanyl Alcohols and their Self-Condensation Polymers

2,5-Bis(hydroxymethyl)furan (BHMF) as well as furfuryl alcohol (FFA) are considered as highly valuable biomass-derived alcohols resembling aromatic monomers in polymer synthesis. Herein, a series of cobaltic nitrogen-doped carbon (Co-NC) catalysts calcinated at different temperatures were synthesized and tested for the solvent-free hydrogenation of 5-hydroxymethylfurfural (HMF) to prepare BHMF. It was found that the Co-NC catalyst calcinated at 600 °C (Co-NC-600) exhibited a superior catalytic activity in the hydrogenation reaction mainly due to the doping of graphitic N, which probably facilitated the polarization of H₂ to afford H⁺ and H^- . Consequently, Co-NC-600 offered a high BHMF/FFA yield greater than 90 % with a nearly complete conversion of HMF/furfural (FF) at the optimal conditions (80 °C, 4 h, and 5 MPa H₂ ). After the hydrogenation reaction, Co-NC catalyst was facilely recycled by magnetic separation, and the obtained BHMF/FFA was then successfully transformed into hypercrosslinked polymers with an excellent CO₂ /H₂ storage capacity comparable to aromatic hydroxymethyl polymers. Therefore, this is a novel and facile two-step pathway for the conversion of biomass-derived HMF/FF towards functional polymers from both industrial and environmental perspectives.

Electrochemical immunosensor based on AuNPs/Zn/Ni-ZIF-8-800@graphene for rapid detection of aflatoxin B1 in peanut oil

Peanut oil is a basic food raw material in life. However, aflatoxin contamination in peanut oil is considered to be one of the most serious food safety problems in the world. Based on AuNPs/Zn/Ni-ZIF-8-800@graphene composite, a simple, efficient and sensitive electrochemical immunosensor was developed to detect aflatoxin B1 (AFB1) in peanut oil. The bare glassy carbon electrode was modified by graphene, bimetallic organic framework material (Zn/Ni-ZIF-8-800), chitosan and gold nanoparticles. The electrochemical immunosensor was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FT-IR) and cyclic voltammetry (CV), and the electrochemical signal changes after antibody and AFB1 binding were investigated in detail. Under the optimal conditions, the linear range of the electrochemical immunosensor was 0.18-100 ng/mL, and the detection limit was 0.18 ng/mL. In addition, the prepared sensor has high selectivity and long-term stability, which lays a foundation for the simple, rapid and sensitive detection of AFB1 in peanut oil.

Zeolitic Imidazolate Framework Membranes: Novel Synthesis Methods and Progress Toward Industrial Use

In the last decade, zeolitic imidazolate frameworks (ZIFs) have been studied extensively for their potential as selective separation membranes. In this review, we highlight unique structural properties of ZIFs that allow them to achieve certain important separations, like that of propylene from propane, and summarize the state of the art in ZIF thin-film deposition on porous substrates and their modification by postsynthesis treatments. We also review the reported membrane performance for representative membrane synthesis approaches and attempt to rank the synthesis methods with respect to potential for scalability. To compare the dependence of membrane performance on membrane synthesis methods and operating conditions, we map out fluxes and separation factors of selected ZIF-8 membranes for propylene/propane separation. Finally, we provide future directions considering the importance of further improvements in scalability, cost effectiveness, and stable performance under industrially relevant conditions. Expected final online publication date for the Annual Review of Chemical and Biomolecular Engineering, Volume 13 is October 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Co3ZnC@NC Material Derived from ZIF-8 for Lithium-Ion Capacitors

Metal-organic framework (MOF)-derived carbon materials were widely reported as the anodes of lithium-ion capacitors (LICs). However, tunning the structure and electrochemical performance of the MOF-derived carbon materials is still challenging. Herein, metal carbide materials of Co3ZnC@NC-8:2 were obtained by the pyrolysis of the MOF materials of Co0.2Zn0.8ZIF-8 (Zn/Co ratio of 8:2). A half-cell assembled with the Co3ZnC@NC-8:2 electrode exhibits a discharge capacity of the electrode material of 598 mAh g-1 at a current density of 0.1 A g-1. After 100 cycles, the retention rate of discharge specific capacity is about 90%. The high performance of Co3ZnC@NC-8:2 is ascribed to its high crystalline degree and well-defined structure, which facilitates the intercalation/deintercalation of lithium ions and buffers the volume change during the charge/discharge process. The high capacitance contribution ratio calculated by cyclic voltammetry (CV) curves at different scanning rates indicates the pseudocapacitance storage mechanism. LICs constructed from the Co3ZnC@NC-8:2 material have a rectangular CV curve, while the charge-discharge curve has a symmetrical triangular shape. This study indicates that MOF-derived carbon is one of the promising materials for high-performance LICs.

A simple strategy for the detection of Pb(II) and Cu(II) by an electrochemical sensor based on Zn/Ni-ZIF-8/XC-72/Nafion hybrid materials

In this study, a novel electrochemical sensor for simultaneous detection of Pb(II) and Cu(II) was constructed by using Zn/Ni-ZIF-8/XC-72/Nafion hybrid material as electrode surface modifier. XRD, FT-IR, XPS and SEM were used to study the crystal structure, functional groups, element types and morphologies of the prepared materials. The electrochemical performance of the Zn/Ni-ZIF-8/XC-72/Nafion/GCE sensor were investigated by CV, EIS and DPV. In addition, the effects of various conditions including pH, the type of buffer and the ratio of Zn/Ni-ZIF-8 to XC-72 were also explored for the determination of Pb(II) and Cu(II). Under the optimum conditions, the constructed sensor exhibited outstanding linear response of Pb(II) (0.794-39.6 ppm) and Cu(II) (0.397-19.9 ppm) with detection limits of 0.0150 and 0.0096 ppm, respectively. Finally, the fabricated sensor was further used to detect Pb(II) and Cu(II) in real samples, and the satisfactory recovery was obtained.

High-performance Fe-doped ZIF-8 adsorbent for capturing tetracycline from aqueous solution

Efficient removal of antibiotics from aqueous solution is of fundamental importance due to the increasingly severe antibiotic-related pollution. Herein, a high-performance Fe-ZIF-8-500 adsorbent was synthesized by Fe-doping strategy and subsequent activation with high-temperature. In order to evaluate the feasibility of Fe-ZIF-8-500 as an adsorbent for tetracycline (TC) removal, the adsorption properties of Fe-ZIF-8-500 were systematically explored. The results showed that the Fe-ZIF-8-500 exhibited ultrahigh adsorption capacity for TC with a record-high value of 867 mg g^-1. Additionally, the adsorption kinetics and isotherms for TC onto the Fe-ZIF-8-500 can be well-fitted by the pseudo-second-order kinetics model and the Freundlich model, respectively. The ultrahigh adsorption capacity of Fe-ZIF-8-500 can be explained by the synergistic effect of multi-affinities, i.e., surface complexation, electrostatic attraction, π-π interaction and hydrogen bonding. After being used for four cycles the adsorption capacity of Fe-ZIF-8-500 remains a high level, demonstrating its outstanding reusability. The ultrahigh adsorption capacity, excellent reusability, satisfactory water stability and easy-preparation nature of Fe-ZIF-8-500 highlight its bright prospect for removing tetracycline pollutant from wastewater.

A review on production of metal organic frameworks (MOF) for CO2 adsorption

The environment sustenance and preservation of global climate are known as the crucial issues of the world today. Currently, the crisis of global warming due to CO₂ emission has turned into a paramount concern. To address such a concern, diverse CO₂ capture and sequestration techniques (CCS) have been introduced so far. In line with this, Metal Organic Frameworks (MOFs) have been considered as the newest and most promising material for CO₂ adsorption and separation. Due to their outstanding properties, this new class of porous materials a have exhibited a conspicuous potential for gas separation technologies especially for CO₂ storage and separation. Thus, the present review paper is aimed to discuss the adsorption properties of CO₂ on the MOFs based on the adsorption mechanisms and the design of the MOF structures. In addition, the main challenge associated with using this prominent porous material has been mentioned.

Mechano-chemical stability and water effect on gas selectivity in mixed-metal zeolitic imidazolate frameworks: a systematic investigation from van der Waals corrected density functional theory

A series of Zn/Cu Zeolitic Imidazolate Frameworks (ZIFs) ZIF-202, -203, and -204 are systematically investigated by Density Functional Theory (DFT) with and without van der Waals (vdW) corrections.

Coexistence of Cu(ii) and Cu(i) in Cu ion-doped zeolitic imidazolate frameworks (ZIF-8) for the dehydrogenative coupling of silanes with alcohols

Recently, metal-ion-doped zeolitic imidazolate frameworks have gained considerable attention for their structure tailorability and potential catalytic applications. Herein, Cu ion-doped ZIF-8 nanocrystals were successfully prepared by the mechanical grinding of Cu(NO₃)₂, ZnO and 2-methylimidazole (HMeIM) using ethanol as an additive. In contrast to the general view that only Cu(ii) is present in Cu-doped ZIF-8, we found the coexistence of Cu(ii) and Cu(i) in this material, which was supported by XPS and X-ray induced Auger electron spectroscopy (XAES) characterizations. Moreover, ethanol might have acted as a reducer to induce the reduction of Cu(ii) during synthesis. Due to the mixed valency of Cu ions, the Cu ion-doped ZIF-8 nanocrystals showed excellent catalytic performance in the dehydrogenative coupling of silanes with alcohols.

Metal–organic framework assisted synthesis of nitrogen-doped hollow carbon materials for enhanced supercapacitor performance

N-Doped hollow carbon materials have been fabricated via the carbonization process by using ZIF-8 coated with PDA.

Waste wool derived nitrogen-doped hierarchical porous carbon for selective CO2 capture

In this work, N-doped hierarchical porous carbon has been successfully fabricated by KOH activation of waste wool. The optimal sample exhibits good CO₂ adsorption capacity under atmospheric pressure (1 bar), as well as excellent CO₂/N₂ selectivity.

Assembly of [Cu2(COO)4] and [M3(μ3-O)(COO)6] (M = Sc, Fe, Ga, and In) building blocks into porous frameworks towards ultra-high C2H2/CO2 and C2H2/CH4 separation performance

Porous MOFs built from paddle-wheel-like [Cu₂(COO)₄] and trigonal prismatic [M₃(μ₃-O)(COO)₆] SBUs exhibit ultra-high C₂H₂ storage as well as C₂H₂/CO₂ and C₂H₂/CH₄ separations at room temperature.

Photoinduced interfacial charge separation dynamics in zeolitic imidazolate framework

We report the ultrafast charge separation dynamics in ZIF-67 through electron transfer to methylene blue.

Solvent-Induced Cadmium(II) Metal-Organic Frameworks with Adjustable Guest-Evacuated Porosity: Application in the Controllable Assembly of MOF-Derived Porous Carbon Materials for Supercapacitors

In this work, five new cadmium metal-organic frameworks (Cd-MOFs 1-5) have been synthesized from solvothermal reactions of Cd(NO₃ )₂ ⋅4 H₂ O with isophthalic acid and 1,4-bis(imidazol-1-yl)-benzene under different solvent systems of CH₃ OH, C₂ H₅ OH, (CH₃ )₂ CHOH, DMF, and N-methyl-2-pyrrolidone (NMP), respectively. Cd-MOF 1 shows a 3D diamondoid framework with 1D rhombic and hexagonal channels, and the porosity is 12.9 %. Cd-MOF 2 exhibits a 2D (4,4) layer with a 1D parallelogram channel and porosity of 23.6 %. Cd-MOF 3 has an 8-connected dense network with the Schäfli symbol of [4²⁴ ⋅6⁴ ] based on the Cd₆ cluster. Cd-MOFs 4-5 are isomorphous, and display an absolutely double-bridging 2D (4,4) layer with 1D tetragonal channels and porosities of 29.2 and 28.2 %, which are occupied by DMF and NMP molecules, respectively. Followed by the calcination-thermolysis procedure, Cd-MOFs 1-5 are employed as precursors to prepare MOF-derived porous carbon materials (labeled as PC-me, PC-eth, PC-ipr, PC-dmf and PC-nmp), which have the BET specific surface area of 23, 51, 10, 122, and 96 m²  g^-1 , respectively. The results demonstrate that the specific surface area of PCs is tuned by the porosity of Cd-MOFs, where the later is highly dependent on the solvent. Thereby, the specific surface area of PCs could be adjusted by the solvent used in the synthese of MOF precusors. Significantly, PCs have been further activated by KOH to obtain activated carbon materials (APCs), which possess even higher specific surface area and larger porosity. After a series of characterization and electrochemical investigations, the APC-dmf electrode exhibits the best porous properties and largest specific capacitances (153 F g^-1 at 5 mV s^-1 and 156 F g^-1 at 0.5 Ag^-1 ). Meanwhile, the APC-dmf electrode shows excellent cycling stability (ca. 84.2 % after 5000 cycles at 1 Ag^-1 ), which can be applied as a suitable electrode material for supercapacitors.

Single Ni sites distributed on N-doped carbon for selective hydrogenation of acetylene

We prepared single Ni atoms embedded in an N-doped carbon catalyst with the assistance of metal organic frameworks.

Beyond pristine MOFs: carbon dioxide capture by metal–organic frameworks (MOFs)-derived porous carbon materials

Porous carbon materials were synthesized by pyrolysis of zinc-based MOFs. These materials exhibited superior CO₂ capacities and better CO₂ separation ability under humid conditions compared to those of the pristine MOFs.

Water-based synthesis of zeolitic imidazolate framework-8 for CO2 capture

ZIF-8 synthesized in aqueous solution has a large surface area and high CO₂ adsorption capacity.

Polymer–metal–organic framework core–shell framework nanofibers via electrospinning and their gas adsorption activities

In this study, we have fabricated of PAN@ZIF-8 core–shell nanofibers by combining electrospinning techniques and the MOF synthesis method.

Nanostructured Co(ii)-based MOFs as promising anodes for advanced lithium storage

A novel kind of Co-containing metal–organic frameworks (Co-BTC MOFs) are firstly developed as anodes for LIBs with excellent electrochemical performance.

Tuning of ZIF-Derived Carbon with High Activity, Nitrogen Functionality, and Yield - A Case for Superior CO2 Capture

A highly effective and facile synthesis route is developed to create and tailor metal-decorated and nitrogen-functionalized active microporous carbon materials from ZIF-8. Clear metal- and pyrrolic-N-induced enhancements of the cyclic CO2 uptake capacities and binding energies are achieved, particularly at a much lower carbonization temperature of 700 °C than those often reported (1000 °C). The high-temperature carbonization can enhance the porosity but only at the expense of considerable losses of sample yield and metal and N functional sites. The findings are comparatively discussed with carbons derived from metal-organic frameworks (MOFs) reported previously. Furthermore, the porosity of the MOF-derived carbon is critically dependent on the structure of the precursor MOF and the crystal growth. The current strategy offers a new and effective route for the creation and tuning of highly active and functionalized carbon structures in high yields and with low energy consumption.

Synthesis of polybenzoxazine based nitrogen-rich porous carbons for carbon dioxide capture

Nitrogen-rich porous carbons (NPCs) were synthesized from 1,5-dihydroxynaphthalene, urea, and formaldehyde based on benzoxazine chemistry by a soft-templating method with KOH chemical activation. They possess high surface areas of 856.8-1257.8 m(2) g(-1), a large pore volume of 0.15-0.65 cm(3) g(-1), tunable pore structure, high nitrogen content (5.21-5.32 wt%), and high char yields. The amount of the soft-templating agent F127 has multiple influences on the textural and chemical properties of the carbons, affecting the surface area and pore structure, impacting the compositions of nitrogen species and resulting in an improvement of the CO2 capture performance. At 1 bar, high CO2 uptake of 4.02 and 6.35 mmol g(-1) at 25 and 0 °C was achieved for the sample NPC-2 with a molar ratio of F127:urea = 0.010:1. This can be attributed to its well-developed micropore structure and abundant pyridinic nitrogen, pyrrolic nitrogen and pyridonic nitrogen functionalities. The sample NPC-2 also exhibits a remarkable selectivity for CO2/N2 separation and a fast adsorption/desorption rate and can be easily regenerated. This suggests that the polybenzoxazine-based NPCs are desirable for CO2 capture because of possessing a high micropore surface area, a large micropore volume, appropriate pore size distribution, and a large number of basic nitrogen functionalities.

Synthesis of FeCo nanocrystals encapsulated in nitrogen-doped graphene layers for use as highly efficient catalysts for reduction reactions

A facile strategy to fabricate FeCo nanocrystals with nitrogen-doped graphene shells has been designed, which involves one-step thermal decomposition of Prussian blue analogue (PBA) Fe3[Co(CN)6]2 spheres. The as-prepared product can be used as a non-precious-metal catalyst with a highly efficient catalytic activity and a magnetically separable capability in the reduction of 4-nitrophenol.

In situ interfacial growth of zeolitic imidazolate framework (ZIF-8) nanoparticles induced by a graphene oxide Pickering emulsion

A novel method of an in situ interfacial growth of nanoparticles induced by a Pickering emulsion was proposed for the fabrication of hollow composites.

Mannitol-based acetal-linked porous organic polymers for selective capture of carbon dioxide over methane

Synthesis of mannitol-based acetal-linked porous organic polymers with considerable CO₂/CH₄ selectivity is reported.

Multi-hydroxyl-containing porous organic polymers based on phenol formaldehyde resin chemistry with high carbon dioxide capture capacity

Synthesis of multi-hydroxyl-containing porous organic polymers with considerable CO₂ capture capability and CO₂/N₂ selectivity is reported.

Cu2+-doped zeolitic imidazolate frameworks (ZIF-8): efficient and stable catalysts for cycloadditions and condensation reactions

Condensations and cycloadditions can be catalyzed by newly synthesized Cu-doped zeolitic imidazolate frameworks (ZIFs). The catalysts were well characterized and reusable.

A novel anode material derived from organic-coated ZIF-8 nanocomposites with high performance in lithium ion batteries

A general method of preparing nanocomposites from carbon-coated ZIF-8 is introduced. Pyrolysis of these nanocomposites gives anode materials with high capacity (750 mA h g⁻¹) and improved cyclability.