Search

Developing an OER electrocatalyst that combines high performance with low cost represents a crucial challenge to address for the widespread adoption and implementation of PEM water electrolyzers. The Ru-based catalyst has garnered significant interest owing to its cost-effectiveness and high activity, positioning it as one of the prime contenders to replace Ir-based catalysts. Nevertheless, Ru-based catalysts are easily corrupted by oxidation at high potential, leading to poor catalyst durability. In this work, we used a simple method to synthesize an electrode material which was a carbon framework-supported coralline RuCo alloy catalyst on the CC surface. The porous and highly conductive carbon framework in RuCo@C/CC effectively anchors the RuCo alloy, preventing its aggregation and detachment from the CC. And the carbon framework also facilitates enhanced mass and charge transfer processes, thereby greatly improving catalytic performance. Additionally, charge transfer and redistribution occur within the RuCo alloy, thereby efficiently reducing the activation energy barrier (via the AEM mechanism) of the OER, consequently enhancing OER performance. Therefore, RuCo@C/CC exhibits outstanding performance in acidic OER, achieving a current density of 10 mA/cm2 at a remarkably low overpotential of 200 mV, significantly surpassing commercial RuO 2 (which requires 280 mV), owing to its exceptional OER kinetics, while also demonstrating exceptional stability in practical PEMWE test. This research introduces a convenient route for creating a highly efficient and durable alloy electrocatalyst, showcasing its promise for Proton Exchange Membrane Water Electrolysis. • Charge transfer and redistribution within RuCo reduce the OER energy barrier. • Role of C skeleton in preventing RuCo shedding and enhancing mass and charge transfer. • RuCo@C/CC shows a low overpotential of 200 mV at η 10 , surpassing commercial RuO 2. [ABSTRACT FROM AUTHOR]

Developing highly active and stable non-noble metal bifunctional electrocatalysts are urgently demanded in overall water splitting. Herein, tunable precursor ratio synthesis of cobalt-based ZIFs as a template derived active cobalt embedded N-doped carbon (Co@NC) catalyst. The rational synthesis of ZIF templates significantly impacts the complex nanostructure and properties of the catalyst (Co@NC). Consequently, the different nanostructures on Co@NC exhibit significance for the electrocatalyst of hydrogen and oxygen evolution reactions. The optimized Co@NC-20 provides excellent electrocatalytic activity with the lowest overpotential of 172 and 301 mV for HER and OER, respectively, at the current density of 10 mA cm−2. The bifunctional Co@NC-20 reveals a potential for overall water splitting as low as 1.68 V of 10 mA cm−2. After continuously working for 24h, the exceptional stability activity maintains 75% of the catalytic performance on Co@NC-20. The beneficial character in the synergistic effects between high-active Co species with well-protection of the metal core by carbon shell promotes their excellent performance. This study provides an essential reference for the rational design of ZIF templates for electrocatalysts with more complex structures in the future. [Display omitted] • Rational fabrication Co-ZIF template for sacrificial into Co@NC. • Ratio precursors (M:L) impact in structure/morphologies Co-ZIF template. • High efficient Co@NC electrocatalysts of OER/HER for water splitting reaction. • High active Co/N species for superior bifunctional electrocatalytic performance. • The carbon shell's well-protected core active site indicates good long-time stability features. [ABSTRACT FROM AUTHOR]

Mixed matrix membranes (MMMs) combine the high separation performance of porous materials with the processibility of polymers and so possess potential for carbon capture from CO 2 -containing gas streams. Zeolitic imidazolate frameworks (ZIFs) are promising candidates as molecular-sieve fillers in MMMs due to their tunability and ease of synthesis. We have compared four ZIFs, all as nanoparticles of similar sizes (ca. 400 nm), as MMM fillers, to investigate the effects of ZIF structure and chemistry on MMM performance of pure gas (CO 2 , N 2) permeation under the same conditions. The chosen ZIFs include two that exhibit strong CO 2 adsorption (hybrid ZIF-7/COK-17 and ZIF-94) and two that have higher pore volumes but weaker CO 2 interactions (ZIF-8 and a hybrid ZIF-11/ZIF-71). The hybrid ZIF-7/COK-17 and ZIF-94 are structurally related to ZIF-7 (rhombohedral sod topology) and ZIF-8 (cubic sod), respectively, via partial or complete substitution of benzimidazole or 2-methylimidazole by 4,5-dichloroimidazole or 4-methyl-5-imidazolecarboxaldehyde, while the hybrid ZIF-11/ZIF-71 has the rho topology but the same composition as the ZIF-7/COK-17 hybrid. In the first part of the comparative study, MMMs based on two types of commercial polymers, Matrimid®5218 and PEBAX-MH1657, were prepared containing the ZIF-7/COK-17 hybrid and also with ZIF-94. ZIF-94 shows much better compatibility with the polymers, forming homogeneous dispersions at all loadings attempted (≤35 % wt%) whereas the hybrid shows inhomogeneity above 12 wt% in each case. At 12 wt% loading, both fillers show an increase in CO 2 permeability at 1.2 bar and 293 K compared to the pure membrane (in PEBAX, this increases from 49.5 to 60 and 68 Barrer) which is the result of increased solubility compensating for decreased diffusivity, and this improvement in permeability continues to increase at the higher levels of loading possible with ZIF-94. ZIF-7/COK-17 in PEBAX show higher selectivity, achieving a calculated CO 2 /N 2 selectivity up to 70. Further investigation of CO 2 and N 2 permeation on MMMs with the four ZIFs at 12 wt% in PEBAX-MH1657 showed a clear distinction between the ZIF-94 and ZIF-7/COK-17 MMMs (which show higher membrane solubilities but lower diffusivities) compared to ZIF-8 and ZIF-11/ZIF-71 MMMs. At the loading chosen, the CO 2 permeability increase achieved by the four ZIFs over PEBAX-MH1657 increases in the order ZIF-11/-71, ZIF-7-COK-17 (ca. 60 Barrer) < ZIF-94 (68) < ZIF-8 (81), reflecting the complex interplay between CO 2 solubility (increasing with interaction strength) and diffusivity (increasing with available cage and window size). The calculated CO 2 /N 2 selectivity is highest for the hybrid ZIF-7/COK-17 membrane (70), which is attributed to molecular sieving effects in the rhombohedral sod structure. [ABSTRACT FROM AUTHOR]

Co@hollow carbon nanofibers (Co@HCNFs) catalysts with multi-level pore structures were fabricated by coaxial electrospinning, in-situ growth of ZIF-67 and subsequent high temperature pyrolysis. The as-prepared Co@HCNFs-0.6–0.1 catalyst exhibits superior catalytic performance in the CO 2 cycloaddition with epichlorohydrin in the absence of a co-catalyst, achieving super high specific activity of 838 mmol⋅min−1⋅g−1. [Display omitted] • Co@hollow carbon nanofibers with multi-level pore structures were fabricated. • Many Co@CN nanoparticles are uniformly distributed within the carbon nanofibers. • The multi-level pore structures provide more paths for the mass transfer. • Many well-distributed Co@CN nanoparticles provide more catalytic sites. • Co@HCNFs-0.6–0.1 has superior catalytic performance for the CO 2 cycloaddition. In pursuit of carbon neutrality, the development of highly efficient catalysts for the CO 2 cycloaddition with epoxides represents a prominent approach of utilizing CO 2 to produce valuable cyclic carbonates. Herein, Co@hollow carbon nanofibers (Co@HCNFs) catalysts with multi-level pore structures were fabricated by coaxial electrospinning, in-situ growth of zeolitic imidazolate framework-67 (ZIF-67) and subsequent high temperature pyrolysis. The hollow structure and the formation of the active sites of Co@N-doped carbon (Co@CN) were regulated by changing the feeding ratio of core to shell and the Co(NO 3) 2 ·6H 2 O concentration during the ZIF-67 growth, thereby fine-tuning the catalyst structures and its catalytic performance. The as-prepared Co@HCNFs-0.6–0.1 catalyst exhibits superior catalytic performance in the CO 2 cycloaddition and epichlorohydrin without a co-catalyst, achieving superior specific activity of 838 mmol⋅min−1⋅g−1. The outstanding catalytic performance is attributed to its multi-level pore structures with rich N content and well-distributed Co@CN nanoparticles. Moreover, Co@HCNFs-0.6–0.1 exhibits good stability over ten reaction cycles. [ABSTRACT FROM AUTHOR]

[Display omitted] • CF/ZIF-7-NH 2 is acquired through an in-site self-assemble strategy. • CF/ZIF-7-NH 2 enables ultrarapid adsorption for Hg(II) with h of 38.26 mg g−1 min−1. • CF/ZIF-7-NH 2 exhibits outstanding adsorption capacity of 909.09 mg g−1 for Hg(II). • The active and abundant O − and N − sites are responsible for Hg(II) adsorption. Adsorptive removal of mercury ion from wastewater has become a hot topic due to the toxicity and persistence; acquiring adsorbent materials with high-capacity, rapid-kinetic, super-selective while low-cost features are highly demanded. Herein, based on the full functionality of collagen fiber (CF) from the leather waste, we proposed an innovative synthetic approach through exploiting amino-functionalized ZIF-7 (ZIF-7-NH 2) as functional groups to facilely in-situ incorporate with CF, affording low-cost but effective adsorbent materials of CF/ZIF-7-NH 2 composite maximizing both functions of CF and ZIF-7-NH 2 in the Hg(II) capture. Remarkably, it exhibits an ultra-high capacity as high as 909.09 mg g-1, fast kinetics that could remove 99.01 % of 200 mg·L-1 within 20 min, and significant selectivity of S Hg/M (K d Hg / K d M) as large as 522–1017 over Mg2+, K+, Ca2+, Cd2+, and Mn2+. We understand such an impressive adsorption is contributed by the synergistic action between functional groups including on the CF and ZIF-7-NH 2. This study offers an effective method for removing heavy metal ions, achieving efficient removal of Hg(II) ions for pollution control, and promoting the reuse of waste CF to reduce waste accumulation in various aspects. [ABSTRACT FROM AUTHOR]

• The optimized Fe, Cu co-doped ZIF-derived N -doped carbon (FeCu 0.28 -NC) are prepared. • FeCu 0.28 -NC shows a half-wave potential of 0.925 V in 0.1 M KOH for oxygen reduction. • FeCu 0.28 -NC shows good oxygen evolution performance. • Zinc-air batteries show a high-power density of 85 mW cm−2 at 140 mA cm−2. Zinc-air batteries (ZABs) have attracted attention for their environmental friendliness, durability, safety and high energy density. The superior performance of rechargeable ZABs hinges on the activity of oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Here, we successfully develop a Fe, Cu co-doped ZIF-derived N-doped carbon (FeCu x -NC) catalyst, featuring a lamellar "red blood cell" structure. In the ORR process, the optimized FeCu x -NC catalyst achieves a half-wave potential of 0.925 V under alkaline conditions, 70 mV higher than commercial Pt/C catalysts, and exhibits good stability. In the OER process, at 10 mA cm−2, the overpotential is measured at 510 mV and the Tafel slope value is 55.2 mV dec−1. When utilizing optimized FeCu x -NC catalyst without RuO 2 at a catalyst loading of 2 mg cm−1, the assembled ZABs demonstrate a power density of 85 mW cm−2 at 140 mA cm−2, while maintaining excellent cycling stability (with only a 0.11 V increase in the voltage interval between charging and discharging over 300 cycles), thereby realizing the dual function of ORR/OER. [ABSTRACT FROM AUTHOR]

ZIF-8 and ZIF-67 are two highly similar Zeolite iminazolate frameworks (ZIFs) materials. In the field of adsorption, ZIF-8 is more suitable than ZIF-67 in most cases. In the field of catalysis involving electron transfer, ZIF-67 is more reliable. Using these two materials for modification and activation of peroxymonosulfate (PMS), ZIF-67 is a cobalt based metal catalyst, while ZIF-8 volatilizes the zinc node at a calcination temperature above 800 ℃, thereby transforming into a non-metallic catalyst. Generally speaking, ZIF-67 derivatives have better activation effects, while ZIF-8 derivatives have less metal leaching and no concerns about secondary pollution. In addition, some researchers have combined ZIF-8 with ZIF-67 in the hope of combining their advantages. These three types of materials can generate a large number of free radicals and non - radicals by activating PMS, achieving the effect of degrading pollutants. [Display omitted] • Different performances of ZIF-8 and ZIF-67 were illustrated. • The latest progress in improving PMS activation by ZIF-8 and ZIF-67 derivatives. • The advantages and disadvantages of metal catalysts and non-metal catalysts. • Prospects for future research on zinc-cobalt synergistic activation of PMS in AOPs. Zeolite imidazolate frameworks materials (ZIFs, especially ZIF-8 and ZIF-67) used as catalysts for peroxymonosulfate (PMS) activation to generate reactive oxidative species (ROS), such as free radicals and singlet oxygen radicals, for the degradation of organic pollutants in the advanced oxidation processes (AOPs) have received much attention recently. The synthesis and modification methods of ZIF-8 and ZIF-67 were introduced in detail, particularly based on the specificity generated by the differences in the characteristics of the material itself. In additional, the modification of ZIF-8/ZIF-67 composites for activating PMS was systematically discussed for the first time. The feasibility and possible development directions of zinc-cobalt co-catalysis were proposed. Finally, the potential active sites of modified materials in the catalytic process were summarized, the degradation mechanism were elucidated, and the difficulties and challenges that ZIFs still need to face in activating PMS in the future were explained. [ABSTRACT FROM AUTHOR]

The heterometal functionalization on zeolitic-imidazole frameworks (ZIFs) is a strategy to modify properties over the homometal ZIFs. A green strategy for simultaneously functionalized iron atoms during the crystal formation of ZIF-67 (Fe@ZIF-67) through the solid-solid thermal (SST) method is newly developed. The single-step process and absent solvent conditions are beneficial advantages of this SST method over the early reported synthetic methods. The results show that the iron is well-dispersed and homogeneously coordinated in the structure of Fe@ZIF-67. Moreover, the optimal iron-functionalized ZIF-67 (20Fe@ZIF-67) significantly enhances the catalytic performance of CO 2 cycloaddition epoxide by 2.3 times compared to pristine ZIF-67 under mild reaction conditions. The DFT calculation reveals that the iron atom induces the unsaturated sites or defect structure on the Fe@ZIF-67 catalyst, providing more reactive sites for the catalytic activity of the reaction. [Display omitted] • The green strategy of solid-state thermal (SST) method functionalizes iron atoms into ZIF-67 (Fe@ZIF-67). • Single-step under solvent-free and mild conditions are advantages of the SST method. • Iron atoms are randomly dispersed and homogeneously distributed on the obtained Fe@ZIF-67. • Distinctive contributions of hetero-iron in Fe@ZIF-67 play a pivotal role in the catalytic performance. • The Fe atom reveals high binding energy and plays a role in excellent catalytic activity on Fe@ZIF-67. [ABSTRACT FROM AUTHOR]

Oxygen reduction reaction (ORR) has slow reaction rate that decrease the chemical conversion productivity in proton exchange membrane fuel cells (PEMFCs) which has to be improved. Noble metals such as Pt nanoparticles supported on carbon (Pt/C) was considered the most essential catalyst in ORR despite their limitations including being rare and expensive, CO poisoning etc. In the past few years, nitrogen doped carbons (N–C) or zeolitic imidazole framework (ZIFs) derived (M-N-C) including single or bimetallic metals take attention due to their outstanding properties such as high surface area, excellent electrical conductivity, cost effectiveness, thermal and chemical stability which were used either as catalyst or supports for noble metal nanoparticles to improve the sluggish ORR in PEMFC cathode. This review briefly outlines conventional crystal preparation and activation of porous carbons derived from ZIFs and their green synthesis methods, followed by modern synthesis methods of nanostructured MNP/MOF composites and recently their ORR activity evaluation in PEMFC. Particular attention was given to the porous carbon supports derived from two kind of frameworks such as ZIF-8 and ZIF-67 which are the most frequently reported ORR electrocatalysts and/or supports in the literature. [Display omitted] • Synthesis methods for zeolitic imidazolate frameworks (ZIFs) were summarized. • Utilization of ZIFs either catalyst or support were summarized. • ZIFs based porous carbon materials were evaluated in terms of ORR activity. [ABSTRACT FROM AUTHOR]

Zeolite imidazolate frameworks (ZIFs) are a class of highly concerned metal organic frameworks (MOFs) with zeolite like structures. In this study, a convenient, economical and excellent-yield method for ZIFs preparation was built under the chemical principle exploration of ZIFs formation. By loading stoichiometric metal salts and ligands, four ZIF samples were obtained and characterized by XRD, FTIR, BET, SEM and TG. The porous ZIF-8 and ZIF-67 got high S BET of >1700 m2 g−1 and high yields of 98.3% and 91.7%, respectively. Comparatively, the dense ZIF-zni (Zn) and ZIF-zni (Co) got high yields of 98.6% and 92.0% but very low S BET. ZIF-8 and ZIF-67 were utilized in environmental purification to exhibit good performances in dealing with heavy metals, radionuclides and organic pollutants through adsorption or photocatalysis. The scale-up reaction for ZIF-8 showed that the yield and key performance parameters were almost unchanged, which should be beneficial for mass production. [Display omitted] • A novel method for ZIFs preparation with high yields was built. • The scope of the method was investigated and four ZIF samples were obtained. • ZIF-8 and ZIF-67 got high S BET , while ZIF-zni (Zn) and ZIF-zni (Co) got low S BET. • ZIF-8 and ZIF-67 were proved to be efficient in adsorption and photodegradation. • Scale-up of the reaction showed a good application prospect for industrialization. [ABSTRACT FROM AUTHOR]

• Recent efforts concerning electrochemical CO 2 reduction reactions (CO 2 -ECR) were reviewed. • Enhanced catalytic activity through ZIF nanostructuring. • Machine learning for catalyst design and prediction. • Understanding reaction mechanisms at the atomic scale. • Tailoring catalysts for specific products. The socio-economic advancements have led to the emergence of anthropogenic carbon dioxide (CO 2) emissions, which have had a profound influence on ecosystems and climate change. This review focuses on CO 2 Electrochemical Reduction (CO 2 -ECR), a new technology with significant potential for reducing CO 2 emissions through the optimal use of renewable resources. In recent years, there has been a concerted effort to develop catalysts that are both effective and efficient in order to improve the efficiency of CO 2 -ECR for the production of desired products. Zeolitic imidazolidine frameworks (ZIFs) have gained significant attention in the field of CO 2 -ECR due to their significant surface area and presence of active sites. ZIFs, which consist of imidazole organic linkers and a variety of metals, are tunable with respect to their electrochemical activity and properties, thereby affecting the selectivity of CO 2 -ECR. This review elucidates ZIFs as CO 2 -ECR electrocatalysts, encompassing ligand modifications, metal variations, and different reaction conditions, contributing to the quest for efficient solutions in mitigating CO 2 concentration and achieving carbon neutrality. Researchers have extensively studied operational conditions impacting these materials. Technology utilization further aids in explaining experimental observations. This review has significant potential for application in studying and fabrication of electrocatalytic ZIFs-based materials that are effective for academic and industrial research and development. [ABSTRACT FROM AUTHOR]

The potential electromagnetic interference in rapid emerging of smart and wearable electronics has significantly stimulated the exploration of microwave absorption (MA) materials. Nevertheless, the fabrication of flexible and broadband microwave absorbers remains a great challenge. Herein, the flexible MA films have been fabricated through constructing bimetallic ZIFs derived hierarchical superstructures onto carbon-fiber cloth and subsequent polymer encapsulation. By controlling the synthesis condition, three types of hierarchical CoZn-ZIF superstructures with different morphology of building block on cotton-fiber (CC/ZIFs) have been successfully yielded. After subsequently two-step morphology-preserved thermal transformation process, the derived superstructures are comprised of hollow Co 3 O 4 nanosphere embedded in carbon frameworks on flexible carbon-fiber cloth (CC/ZIFs-300). The superstructures coupled with carbon-fiber cloth have effectively promoted electron transportation, conductive loss, polarization loss, multi-scattering, and impedance matching. As expected, the flexible MA films exhibit ideal MA performances, and the largest effective absorption bandwidth can reach as 11.6 GHz. This work provides a novel concept for further design of flexible MA materials. [Display omitted] • The flexible microwave absorption films have been fabricated from bimetallic ZIFs on cotton-fiber cloth. • The superstructures coupled with carbon-fiber cloth have effectively promoted dielectric loss capacity. • Hollow Co 3 O 4 particles and carbon framework could improve the dipole polarization loss and impedance matching. • The largest effective absorption bandwidth can reach as 11.6 GHz. [ABSTRACT FROM AUTHOR]

• Genetic algorithm boosts the synthesis of high-quality MOFs via a microdroplet route. • ZIF-8 with highest surface area (1748 m2/g) is achieved with least trial and error. • General guidance is derived and demonstrated with the synthesis of ZIF-67. As an emerging strategy for the synthesis of metal-organic frameworks (MOFs), a microdroplet-based spray method holds merits of improved heat and mass transfer rates, which allows the formation of MOF crystals in a much faster manner. To optimize the spray route for the MOF synthesis, further exploration is needed to understand the dominant variables controlling the quality of the products. With a series of experiments and advanced computational analysis, we present here general guidance for the synthesis of representative zeolitic imidazolate frameworks (i.e., ZIF-8 and ZIF-67) using the spray route. [ABSTRACT FROM AUTHOR]

Nickel sulfide-based materials have shown great potential for electrode fabrication owing to their high theoretical specific capacitance but poor conductivity and morphological aggregation. A feasible strategy is to design hybrid structure by introducing highly-conductive porous carbon as the supporting matrix. Herein, we synthesized hybrid composites consisting of interconnected NiS-nanosheets and porous carbon (NiS@C) derived from Zeolitic-imidazolate frameworks (ZIFs) using a facile low-temperature water-bath method. When employed as electrode materials, the as-prepared NiS@C nanocomposites present remarkable electrochemical performance owing to the complex effect that is the combined advantages of double-layer capacitor-type porous carbon and pseudocapacitor-type interconnected-NiS nanosheets. Specifically, the NiS@C nanocomposites exhibit a high specific capacitance of 1827 F g−1 at 1 A g−1, and excellent cyclic stability with a capacity retention of 72% at a very high current density of 20 A g−1 after 5000 cycles. Moreover, the fabricated hybrid supercapacitor delivers 21.6 Wh kg−1 at 400 W kg−1 with coulombic efficiency of 93.9%, and reaches 10.8 Wh kg−1 at a high power density of 8000 W kg−1, along with excellent cyclic stability of 84% at 5 A g−1 after 5000 cycles. All results suggest that NiS@C nanocomposites are applicable to high-performance electrodes in hybrid supercapacitors and other energy-storage device applications. • The interconnected NiS@C with hybrid structure was synthesized. • The NiS@C delivers a high specific capacitance of 1827 F g−1 at 1 A g−1. • The NiS@C shows excellent cyclic stability of 72% at 20 A g−1 after 5000 cycles. • The hybrid device exhibits a high energy density of 21.6 Wh kg−1 at 400 W kg−1. [ABSTRACT FROM AUTHOR]

N-doped carbons (NCs) have attracted considerable attention for their outstanding physicochemical properties, including tunable porosity, electronic features and modified surface. Here, we report the preparation of hierarchically porous NCs derived from the direct pyrolysis of ZIFs (ZIF-7 and ZIF-8) and poly– m –phenylenediamine-covered carbon black (P m PDA-C) for the stabilization of Cu nanoparticles (NPs). The configuration of N species can be effectively regulated by changing the ligand of ZIFs and pyrolysis atmosphere. A remarkable N configuration synergistic effect is observed in the oxy-carbonylation of methanol to dimethyl carbonate with molecular oxygen. The results indicate that the Cu NPs on pristine carbon have a turn over frequency (TOF) of 4.4 h−1 for the reaction, while those on NCs from ZIF-8 and ZIF-7 present TOF values as high as 17.9 h−1 and 28.5 h−1, respectively. The extensive characterizations reveal that NCs with a nitrogen content of 2–5 wt% and a pyrrolic-/pyridinic-N molar ratio of 2–3 are vital for the performance enhancement of Cu NPs. This work shows that the stabilization and enhanced performance of active Cu NPs on NCs are realized by the rational design of precursors to generate the proper N configurations. Image 1 • A series of NCs are prepared from ZIFs with N content in the range of 0–20 wt%. • The N configuration is regulated by ligand of ZIFs and varying pyrolysis conditions. • The performance of supported Cu catalysts is correlated with N configurations. • NCs with 2–5 wt% N and pyrrolic-/pyridinic-N ratio at 2–3 are vital for Cu catalysis. [ABSTRACT FROM AUTHOR]

With the intensification of ecological environment problems and the improvement of public awareness of ecological civilization construction, as well as the global warming and climate change caused by excess CO 2 in the atmosphere, the problem of excessive CO 2 emission has received extensive attention globally in recent years and researchers have focused their attention on the technology of CO 2 capture, utilization and storage (CCUS). CO 2 cycloaddition with epoxide, as an efficient approach to fix and convert CO 2 , can solve the environmental concerns and reduce the dependence on fossil fuels simultaneously, is a promising way for CO 2 utilization. The CO 2 cycloaddition process usually requires catalysts, and zeolite-like imidazolate frameworks (ZIFs) have received extensive attention as a novel and effective catalyst due to its unique physical and chemical properties. Many ZIFs based or derived catalysts with different structures and functions have been developed to achieve efficient catalysis of CO 2 cycloaddition with epoxide. In addition, effects have been made to design suitable catalytic materials and reveal the process mechanism, thus promote the industrialization of the process. In this paper, the recent research progress in the use of ZIFs based or derived catalysts to catalyze this reaction is reviewed, with emphasis on the design, mechanism for the catalysis, as well as the challenges and future prospect for the catalytic system. • ZIFs and ZIFs-based materials for catalytic CO 2 cycloaddition are reviewed. • Design concept of ZIFs and ZIFs-based catalysts and reaction mechanism are summarized. • The challenges and future prospect are concluded for the catalytic system. [ABSTRACT FROM AUTHOR]

• A porous magnetic material (Fe 3 O 4 @3DGA@ZIF-8) is synthesized which is easy to recycle. • The isothermal and kinetic curves were fitted to illustrate the adsorption mechanism a certain extent. • Fe 3 O 4 @3DGA@ZIF-8 have a high specific surface area, fast adsorption rate, and fairly repeating utilization factor. • Fe 3 O 4 @3DGA@ZIF-8 is very effective in removing caffeine, especially in adsorbing in tea soup - all over 98%. As more and more adverse health effects of caffeine are being discovered, decaffeinated drinks are receiving increasing attention. In this work, a magnetic imidazole zeolite backbone compounded with three-dimensional graphene was successfully synthesized as a solid adsorbent using a layer-by-layer self-assembly technique, which can rapidly and effectively adsorb caffeine from tea. Meanwhile, the structure and properties of caffeine in tea were investigated by various physicochemical characterization tools. The analytical data showed that Fe 3 O 4 @3DGA@ZIF-8 had a specific surface area of 162.9754 m2/g and an adsorption capacity of up to 19.57 mg/g with a maximum adsorption rate of 96.55%, which could be maintained with good adsorption repeated utilization three times. The adsorption isotherm and the adsorption kinetic better fit with the Langmuir model and the preudo-second order kinetic model, respectively. Therefore, Fe 3 O 4 @3DGA@ZIF-8 is a good magnetic adsorbent for the separation and the effective removal of caffeine from tea sample. [ABSTRACT FROM AUTHOR]

• The bonding energy between linkers and benzene/vinyl acetate are obtained by DFT calculation. • Binary mixtures benzene/vinyl acetate separation in ZIFs are examined for the first time. • Monte Carlo simulations effectively reproduce adsorption isotherm in ZIFs and selectivity has been calculated. • ZIF-68 is potentially a good material to separate trace benzene from vinyl acetate. The removal of trace benzene from vinyl acetate with zeolitic imidazolate frameworks (ZIFs), a kind of metal-organic frameworks (MOFs) with formula unit M(IM) 2 is studied. ZIF-2, ZIF-3, ZIF-6, ZIF-8, ZIF-10, and ZIF-68 are selected to study the adsorption of benzene and vinyl acetate. Density functional theory (DFT) method is used to study the interaction of the adsorbed molecules with the metal and organic linkers of ZIFs. Various adsorption positions are examined and the preferred configurations are obtained. The adsorption isotherms of benzene and vinyl acetate in pure components and benzene/vinyl acetate mixtures (0.01%/99.99%) in ZIFs at 373 K are obtained by molecular simulation. The calculation results showed that ZIF-68 has the highest selectivity for benzene. [ABSTRACT FROM AUTHOR]

[Display omitted] • One-pot synthesis of ZIF-67@FePc effectively enhances the crystallinity of the material. • Iron and cobalt bimetallic synergies effectively improve GA sensor response. • Co/FeO X @NC-800/GCE has an ultra-sensitive electrochemical response to gallic acid. • Co/FeO X @NC-800/GCE successfully used for GA detection in various food products. Gallic acid is widely used as an antioxidant in food because of its good antioxidant function, but excessive intake induces side effects in humans, so it is essential to devise a highly responsive technique for detecting gallic acid. In this work, we synthesized ZIF-67@FePc by the one-pot method. The synthesized material is more stable at high temperatures compared to ZIF-67 and maintains its original morphology during pyrolysis, when iron was introduced as a second metal active site during the synthesis process. Subsequently, Co/FeO X @NC-800 was employed to fabricate a GA sensor on a GCE. The developed sensor exhibited remarkable sensitivity towards GA, featuring a low LOD of 1.30 nM and a linear range spanning from 5 to 4500 nM. The electrochemical sensors we have prepared also showed good selectivity, stability, and reproducibility. It has been successfully employed for detecting GA in actual samples such as apples, grapes, tomatoes, and red wine. [ABSTRACT FROM AUTHOR]

To address the global energy crisis and widespread environmental deterioration issues, semiconductor photocatalysts have been widely recognized and studied. In this direction, new-age materials as zeolitic imidazolate frameworks (ZIFs), belonging to a sub-class of metal-organic frameworks (MOFs) have piqued the interest of researchers as prospective photocatalyst candidates. With huge specific surface area, tuneable porosity, diverse structure, ease of designing and controllable properties, ZIFs are highly sought-after material for pollutant degradation and clean energy generation. Additionally, ZIFs may undergo thermal processing to produce functional substances with similar structural characteristics but improved light responsiveness and electron transfer abilities. Numerous functional materials and better photocatalysts can be prepared by thermal treatment of ZIFs, formation of composites, heterostructures with other semiconductors or electron mediators which may have similar structural characteristics but better light capture abilities, charge transfer capabilities and strong redox properties. This paper carefully summarizes and analyses the applications of ZIFs based photocatalysts for photocatalytic organic pollutant degradation, hydrogen generation and CO 2 conversion. A sincere attempt has been made to lay down mechanistic insights into synergism of the structural and electronic properties of ZIFs with other catalyst counterparts for superior photocatalytic performance with focus on band structure analysis, charge transfer mechanisms and performance. Finally, the achievements, novelties and bottlenecks have been discussed and future research directions have been proposed. [Display omitted] • ZIFs as photocatalytic materials-Special structure and properties. • Synthetic routes to ZIFs based composites and heterojunctions. • Applications for CO 2 reduction, H 2 evolution and water treatment. • Detailed discussion on synergism with semiconductors and mechanisms. • Challenges, opportunities and future prospects were fully debated. [ABSTRACT FROM AUTHOR]

In situ generation of H 2 O 2 by photocatalyst with sterilization is an environmentally friendly method. In this work, we prepared three kinds of Zn-based ZIFs materials, i.e., MAF-6, ZIF-11 and ZIF-71, and systematically investigated their application in the area of photocatalytic H 2 O 2 production, and antibacterial efficiency. It is found that MAF-6 had the best ability of generate H 2 O 2 (1005 μmol h-1g-1), 1.6 times more than ZIF-11, while ZIF-71 produced almost no H 2 O 2. The sterilization rate of MAF-6 against Staphylococcus aureus and Escherichia coli can reach 97% and 91% in 3 h, respectively. It is worth noting that the more photo-generated reactive oxygen species (∙OH and ∙O 2 -) are produced, the better sterilization effect. This work provides new material and insights into photocatalytic sterilization by in situ H 2 O 2 generation. [Display omitted] • Three Zn-based ZIFs are successfully fabricated at room conditions. • The photocatalytic performance has the order of MAF-6 >ZIF-11 >ZIF-71. • The main ROS is∙O 2 - and ∙OH. • The mechanism is proved by experiment and DFT calculation. [ABSTRACT FROM AUTHOR]

Abstract Due to the importance of food safety, natural edible pigments attract more and more attention. Because of the application of adsorption technology in the extraction and purification of natural edible pigments, it is necessary to develop a highly efficient adsorbent. In this paper, we prepared a series of core shell spherical adsorbents (CSS-ZIFs) having different types of zeolitic imidazolate frameworks (ZIF-67, ZIF-7, ZIF-8 and ZIF-9) nanoparticles as the shell on the resin microsphere as the core. The XRD、BET and SEM characterizations proved the core-shell structure of the CSS-ZIFs, and the adsorption performance of the CSS-ZIFs were further studied for removing a natural edible pigment (Roselle red) from water. The CSS-7 (ZIF-7 as the shell) showed the best removal rates of 95.3–97.7% mainly due to the strong π-π attraction and weak cation-cation repulsion between ZIFs and Roselle red molecules. This study demonstrates that novel CSS-ZIFs can be used as a kind of feasible adsorbents for Roselle red extraction and separation, and further applied to the adsorption separation of other natural active substances. Graphical abstract A series of new adsorbents with core-shell structure, CSS-ZIFs were successfully prepared and the adsorption properties for Roselle red were investigated. The π-π attraction and cation-cation repulsion between different ZIF shells and Roselle red molecules affects the adsorption performance. Unlabelled Image Highlights • Preparation of core-shell resin microspheres with ZIF-7, ZIF-8, ZIF-9 and ZIF-67 shells • The effect of ZIFs shells of adsorption of Roselle red dye from water • CSS-7 microspheres with ZIF-7 shells showing the best adsorption performance • Adsorption mechanism including strong π-π attraction and weak cation-cation repulsion [ABSTRACT FROM AUTHOR]

Through simply adjusting the water proportion in the synthesis solvent, a series of ZIF materials were prepared and applied in the CO 2 cycloaddition without solvent and co-catalyst. The water proportion significantly affects the morphology, crystal structure, yield, pore structure, CO 2 adsorption capacity, and acidic/alkaline sites of ZIFs, and their catalytic performance for the CO 2 cycloaddition with epoxides. [Display omitted] • ZIFs were prepared by adjusting the water proportion in the synthesis solvent. • The water proportion affects the morphology, crystal structure and yield. • The water proportion influences the pore structure and CO 2 adsorption capacity. • The water proportion affects the acidic/alkaline sites and catalytic properties. • ZIF-(80)-Co shows excellent catalytic capacity for the CO 2 cycloaddition. The cycloaddition of CO 2 with epoxides is an important strategy to reach the goal of carbon neutral, at the same time high-value-added products can be obtained. The integration of Lewis acidic and alkaline sites makes ZIFs potential catalysts for the CO 2 cycloaddition. Herein, through simply adjusting the water proportion in the synthesis solvent, a series of ZIF materials were prepared and applied in the CO 2 cycloaddition. The transitional ZIF-(80)-Co combines the advantages of two-dimensional and three-dimensional ZIFs, namely the two-dimensional morphology, well-developed porous structures, higher CO 2 adsorption capacity, and rich acidic/alkaline sites. The outstanding microstructures and surface properties of ZIF-(80)-Co contribute to its superior catalytic performance for the CO 2 cycloaddition, and an epichlorohydrin (ECH) conversion of 96.9 % and a cyclic carbonate selectivity of 98 % are achieved without solvent and co-catalyst. Importantly, the cycloaddition of CO 2 with ECH over ZIF-(80)-Co is faster than most of the reported ZIFs in literature. Furthermore, ZIF-(80)-Co also exhibits excellent catalytic performance in the CO 2 cycloaddition with epoxy butane, allyl glycidyl ether, cyclohexene oxide and styrene oxide. [ABSTRACT FROM AUTHOR]

As an emerging class of nanoporous materials, Metal Organic Framework (MOFs) are distinguished for environmental remediation. ZIFs and Ni-MOF chosen as fluoride (F-) scavengers due to their robust structures and straightforward synthesis routes. F- adsorption was studied as a function of the ZIFs geometry and structural properties. The efficacy of MOFs for F- abatement was in the order of ZIF-67-NO3 (70.1%) > ZIF-8-Cube (64.7%) > ZIF-67-OAc (62.4%) > ZIF-8-Cuboid (59.2) > Ni-MOF (58.5%) > ZIF-8-Octahedron (57.1%) > ZIF-8-Leaf (55.3%) > ZIF-67-SO4 (55.1%) > and ZIF-67-Cl (52.3%). The key operating variables i.e. pH, mixing time, F- concentration, and ZIF-67-NO3 dose were modeled using the Box-Behnken design (BBD). The model revealed the process mainly influenced by solution pH. The model optimized the operating condition and obtained a maximum 85.9% F- removal by mixing time = 41.1 min, ZIF-67-NO3 dose = 0.9 g/L, solution pH = 4.86, and F- = 6.5 mg/L. Non-linear form of isotherm and kinetic models disclosed the multilayers F- adsorption onto ZIF-67-NO3 with an qmax =25.9 mg/g, and chemisorption as the rate-controlling step. F- sorption decreased slightly by temperature in the range of 303 to 323 K. The structure of ZIF-67-NO3 remained stable under three consecutive use-reuse cycles with an about 10% loss in removal efficiency. [ABSTRACT FROM AUTHOR]

Interest towards metal organic frameworks has experienced an exceedingly fascinating growth in the past decade due to the unique features that these materials exhibit, such as tunable structure and pore size, which made them attractive for many different fields of chemistry. Great potential has been shown during the years for the applications of metal nanoparticles in different fields, especially in catalysis. The deeper understanding of the physicochemical properties of ZIFs along with the possibility of fine tuning the crystalline network provided the researchers with an attracting new support material that can furnish a beneficial environment for the encapsulation of metal nanoparticles. Especially, the pore system resembling those of the zeolites provides a confinement for the growth of the metal species, in which the distribution of pore size is usually in the micropore range and is extremely important for catalytic applications. The synthetic modifications that can be carried out prior- or post-synthetically on the ZIF support offer a wide range of different functionalities that can be introduced into the structure to be finally exploited. These moieties are generally very important in the stabilization of the metal nanoparticles of which control of the dimensions is critical to obtain high catalytically active materials. Hitherto, this review is highlighting the role of ZIFs in different catalytic reactions, especially as support of metal nanoparticles, overlooking the MOFs which have been already extensively discussed. [ABSTRACT FROM AUTHOR]

To explore efficient non-noble metal-based electrocatalysts for oxygen reduction reaction (ORR), herein we developed a facile bottom-up approach for the fabrication of a hollow porous carbon sphere codoped with ultra-small Co nanoparticles and uniform nitrogen distribution (Co-HNCS) via one-step pyrolysis of a core-shell type precursor composing of polystyrene (PS) core and bimetallic ZIF (zeolite imidazolate framework) shell. The bimetallic Co-Zn-ZIFs (BMZIFs) was selected as the sacrifice template due to not only its high nitrogen content and regular porosity but also the superiority that Zn species in BMZIFs can both spatially separate Co species to suppress the aggregation of ultra-small Co NPs and be evaporated to afford extra pores during high-temperature pyrolysis. As expected, by adjusting the starting molar ratio of Zn to Co, we were able to prepare Co-HNCS- x ( x represent the molar ratio of Co to total starting metal feeding) that exhibited unique hollow structure with large surface areas, enhanced mass transport, high porosities, tunable particle sizes and graphitization degrees, abundant highly active CoN x sites, and thus significantly improved ORR performance. Particularly, the optimal Co-HNCS-0.2 exhibited the remarkable ORR activity (the onset and half-wave potentials were 0.94 and 0.82 V vs. RHE, respectively) via an efficient four-electron-dominant ORR process in alkaline medium, which outperformed that of commercial Pt/C (20 wt%, the onset and half-wave potentials were 0.93 and 0.80 V vs. RHE, respectively) and most of previously reported Co-based catalysts. Moreover, it also displayed much superior stability and tolerance to methanol as compared to Pt/C, further highlighting the merit of this facile synthesis approach. Our findings might inspire new thoughts on the development of precious-metal-free, highly-efficient and cost-effective ORR electrocatalysts derived from MOF. [ABSTRACT FROM AUTHOR]

The water vapor and trace gas impurities play important roles on CO 2 capture performance using porous materials. We investigated the effects of H 2 O, SO 2 , and O 2 on CO 2 capture in a series of ZIFs with same SOD topology but different functional groups, such as ZIF-8, ZIF-90, ZIF-Cl, ZIF-NO 2 , and SALEM-2 by grand canonical Monte Carlo simulations. The results show that H 2 O and SO 2 show a cooperative effect on CO 2 adsorption in ZIF-NO 2 and ZIF-90 containing polar functional groups, which results in enhanced CO 2 /N 2 selectivity in presence of H 2 O or SO 2 . Especially, the presence of H 2 O or SO 2 can enhance the CO 2 uptake amounts and the CO 2 /N 2 selectivity in ZIF-NO 2 at all H 2 O or SO 2 concentration. On the other hand, the presence of H 2 O, SO 2 has negligible effect on CO 2 adsorption and CO 2 /N 2 separation in ZIF-8, ZIF-Cl, and SALEM-2. The presence of O 2 has no effect on CO 2 capture in all of the materials investigated. Our results indicate that, by changing the functionalities of ZIF materials, H 2 O and SO 2 may play a positive role during CO 2 adsorption and separation process. [ABSTRACT FROM AUTHOR]

One-dimensional Co@CNFs catalysts were synthesized by one-step pyrolysis of electrospinning ZIF-67-mixed nanofibers. Higher specific surface area and abundant hierarchical pores, enhanced surface defects and acidic/alkaline sites, and more Co nanoparticles with small particle size can be obtained by adjusting the pyrolysis temperature and ZIF-67 amount, thereby superior catalytic performance for the CO 2 cycloaddition with epoxides. [Display omitted] • Novel Co@CNFs catalysts were synthesized by in-situ pyrolysis of ZIF-67@NFs. • The pyrolysis temperature significantly affects the microstructures of Co@CNFs. • The ZIF-67 amount obviously affects the microstructures of Co@CNFs. • Co@CNFs-700–0.45 has superior catalytic performance for the CO 2 cycloaddition. • Co@CNFs-700–0.45 can be easily recovered due to its magnetic property. CO 2 cycloaddition with epoxides to produce cyclic carbonates is a promising method for the resourceful use of CO 2 , but it remains a great challenge. Herein, one-dimensional Co@carbon nanofibers (Co@CNFs) catalysts were synthesized for the first time by one-step pyrolysis of electrospinning ZIF-67-mixed nanofibers, and their microstructures and catalytic performance for the CO 2 cycloaddition with epichlorohydrin were controlled by adjusting the pyrolysis temperature and ZIF-67 amount. The as-prepared Co@CNFs-700–0.45 catalyst shows the highest catalytic activity, which is 1.9 times higher than Co@CNFs-450–0.45 and 1.3 times higher than Co@CNFs-900–0.45. Higher specific surface area and abundant hierarchical pores, enhanced both surface defects and acidic/alkaline sites, and more Co nanoparticles with small particle size are the key reasons for the superior activity of Co@CNFs-700–0.45. Furthermore, good recoverability of Co@CNFs-700–0.45 is due to its one-dimensional and magnetic properties, which is approved by the excellent stability during six reaction cycles. [ABSTRACT FROM AUTHOR]

[Display omitted] • DBU can overcome the slow kinetics of nucleation and crystallization of zeolitic imidazolate framework. • In the rapid crystallization process, DBU functions as a template and inducer, and remains in the framework. • The DBU-PO@ZIF-8 composite show a high catalytic activity for synthesizing EMC by transesterification. • The catalytic mechanism of DBU-PO@ZIF-8 in the transesterification was explored and revealed. Methyl ethyl carbonate (EMC) is the primary raw material for the electrolyte of lithium-ion batteries. It is mainly prepared by the transesterification reaction of dimethyl carbonate (DMC) and EtOH. However, homogeneous alkaline catalysts such as sodium alcohol commonly used in industry are easy to deactivate and challenging to separate and recover. Therefore, the alkaline ionic liquid decorated zeolitic imidazolate frameworks (IL@ZIFs) heterogeneous catalysts were prepared using a simple method with DBU as an inducer. In the synthetic route of IL@ZIFs, the ligand of ZIFs can form an ionic liquid with DBU, and deprotonated ligands will rapidly coordinate with metal ions at room temperature. The DBU can also play the structural guidance and stabilizer, which is conducive to the rapid and effective preparation of ZIFs materials. Meanwhile, the DBU, which has a large molecular diameter, will be trapped in the pore cage and can combine with other protic materials (imidazole, triazole, 2-methylimidazole, phenol, etc.) to form alkaline ionic liquids. The prepared DBU-IL@ZIFs were used as heterogeneous catalysts for synthesizing EMC by transesterification reaction. The DBU-PO@ZIF-8 composite with phenol as anion has better catalytic activity. Under the appropriate reaction conditions, the yield of EMC can reach 55.7% with high selectivity of 94.7%. The catalytic mechanism of DBU-PO@ZIF-8 in the transesterification reaction was also explored and revealed. [ABSTRACT FROM AUTHOR]

[Display omitted] • The oxygen evolution reaction (OER) is a crucial electrochemical reaction of water-splitting system. • Cobalt-based bimetallic zeolitic imidazole frameworks (ZIFs) and their derivatives are extensively utilized. • Only cobalt-based bimetallic ZIFs used as electrocatalysts during OER are discussed. • Future prospects for bimetallic ZIF-derived carbon-based materials for OER electrocatalysis are discussed. Oxygen evolution reaction (OER) is a crucial electrochemical reaction in metal-air batteries and water-splitting system. It is of utmost importance for these devices to achieve highly efficient clean energy production and storage. The zeolitic imidazolate frameworks (ZIFs) have received a lot of attention as a new type of crystalline porous materials due to their large surface area, high porosity, large pore volume, and easy functionalization as well as promising precursors to produce carbon-based electrocatalysts with high electrical conductivity. Cobalt-based bimetallic ZIFs with two distinct metal ions hold specific synergistic effects that demonstrate water oxidation performance and stability better than those of individual monometallic ZIFs. This review focuses on cobalt based bimetallic ZIFs; their advantages, synthesis and modification methods, derived compounds, synergistic effects, and activity of electrocatalysts during OER. We have summed up the application of bimetallic ZIFs and their derivatives in oxygen evolution reaction for the first time, that has sparked a lot of interest in this field. Finally, the future prospective of bimetallic ZIF-derived carbon-based materials for OER electrocatalysis is briefly discussed. [ABSTRACT FROM AUTHOR]

Metal–Organic Frameworks (MOFs) offer considerable potential for applications in adsorption due to their large pore volumes and surface areas. Studies on mechanical stability of MOFs are scarce. Seminal experimental work has shed a new light on the role that elastic constants play in establishing the structural stability of the prototypical ZIF-8 MOF, with its elastic deformation mechanism being linked to the pliant ZnN 4 tetrahedra (Tan et al., 2012). Over the past decade several classical flexible force fields have been proposed to study the physical properties of the system using simulations (Zheng et al., 2012; Hu et al., 2012; Zhang et al., 2013, Wu et al., 2014; Krokidas et al., 2015; Weng and Schmidt, 2019; Dürholt et al. 2019). In this work, we evaluated the majority of them for reproducing structural and mechanical properties (unit cell sizes as a function of temperature and pressure, and elastic constants as a function of pressure), compared them to existing DFT calculations (Tan et al., 2012; Maul et al., 2019) and found that they provide different results under the same testing conditions. The obtained results provide insight into the relationship between fundamental elastic properties and the chosen force field parametrization, allowing us to characterize the applicability of each of the force fields. Furthermore, the employed two-code approach allowed us to find significant discrepancies in elastic constant values for the same force field between methodologies that employ different energy minimization algorithms, suggesting that eigenmode-following approaches might be needed to guarantee true minimum energy configurations for ZIFs. • Classical ZIF-8 force fields (FFs) evaluated for reproducing mechanical properties. • Evaluated FFs unable to reproduce DFT non-linear behaviour of ECs for P > 0.2 GPa. • Estimation of 0 K structures and elastic constants depend on minimization procedure. • Eigenmode-following technique provides consistent results for elastic constants. [ABSTRACT FROM AUTHOR]

Wearable electrochemical biosensors for perspiration analysis offer a promising non-invasive biomarker monitoring method. Herein, a functionalized hybridized nanoporous carbon (H-NPC)-encapsulated flexible 3D porous graphene-based epidermal patch was firstly fabricated for monitoring sweat glucose, lactate, pH, and temperature using simple, cost-effective, laser-engraved, and spray-coating techniques. The fabricated H-NPC-modified electrode significantly increased electrochemical surface area and electrocatalytic activity. Within the physiological sweat range (0–1.5 mM), the second-generation glucose sensor exhibited an excellent sensitivity of 82.7 μAmM−1cm−2 with 0.025 μM LOD. Moreover, the lactate biosensor exhibited an extraordinary linear range (0–56 mM) response owing to the incorporation of an outer diffusion limiting layer (DLL) that controls the lactate flux reaching the enzyme with comparable sensitivity (204 nAmM−1cm−2) and LOD (4 μM). Finally, we employed an analytical correction approach incorporating pH and temperature adjustments during on-body tests. In addition to connecting various carbon-based materials to limitless metal-organic frameworks as a transduction material, our research also paves the way for enabling these sensors to operate on pH and T correction independently while delivering accurate results. [ABSTRACT FROM AUTHOR]

In this contribution, zeolitic imidazolate framework (ZIF-7)/polydimethylsiloxane (PDMS) mixed matrix membranes (MMMs) with uniformly dispersed ZIF-7 were fabricated. The homogeneous dispersion of ZIF-7 nanoparticles in PDMS matrix and better interface compatibility were characterized by SEM and EDS. PV performance reveals that the MMMs display increased total flux and the highest separation factor occurs at 20 wt% ZIF-7 loading, which were 1689 g m −2 h −1 and 66 respectively as compared to 1080 g m −2 h −1 and 51 for pure PDMS membrane when separating 1 wt% butanol aqueous solution at 60 °C. The total flux reaches 3496 g m −2 h −1 with 80 wt% butanol in permeate for the enrichment of 5 wt% butanol solution at 60 °C. The enhanced flux may result from enlarged free volume in the polymer matrix caused by the incorporation of ZIF-7 nanoparticles. Moreover, the super-hydrophobic ZIF-7 pore channels and butanol preferential permeation may contribute to the improvement of separation factor. The result also shows that there is a 21.1% reduction of energy barrier for penetrant transportation for 20 wt% ZIF-7 filled PDMS membrane as compared to pristine PDMS membrane. A long period of pervaporation experiment was also carried out to investigate the structure stability of the ZIF-7/PDMS membrane, and the MMM remains intact during the 240 h continuous operation, which is the key to industrial application for membrane-based separation process. All above indicated that ZIF-7 is a good filler to fabricate butanol permselective pervaporation membranes for butanol separation and enrichment. [ABSTRACT FROM AUTHOR]

Pancreatic cancer is a lethal malignancy and only around 4% of patients will live 5 years post-diagnosis. Photodynamic therapy (PDT) is a promising strategy for treating malignant tumors because of its high selectivity. Through the colocalization of light, oxygen and photosensitizer, a large number of reactive oxygen species (ROS) are generated under excitation at a specific wavelength of a laser, which can induce DNA damage and destroy cancer cells. However, the repair mechanism of cell will repair part of the damaged DNA, which could reduce the efficiency of PDT. The poly (ADP-Ribose) polymerase (PARP) plays a wide and multifaceted role in the cellular response to DNA damage, with growing evidence for participation in multiple pathways of DNA damage repair and genome maintenance. Cells require PARP to resolve single-strand DNA breaks (SSBs) induced by chemotherapy agents. Its inhibition is thought to result in the accumulation of damage in DNA, which may eventually lead to cell death. The combination therapy of PDT and PARP inhibitors may benefit patients. In this study, we design and synthesize a zeolitic imidazolate framework-8 (ZIF-8) to co-deliver DNA damaging agent Chlorin e6 (Ce6) and PARP inhibitor Olaparib (Ola). Ce6 and Ola demonstrate strong synergistic actions, providing a novel approach for the treatment of pancreatic cancer. [ABSTRACT FROM AUTHOR]

[Display omitted] • Guest@host LPOM@ZIFs were acquired through an in-site self-assemble strategy. • LPOM@ZIFs enable ultrarapid adsorption for Pb(II) with h of 412.5 mg g−1 min−1. • LPOM@ZIFs exhibit outstanding adsorption capacity of 764 mg g−1 for Pb(II). • LPOM@ZIFs allow to demetallize 71770 ppb of Pb(II) to 1.84 ppb within 15 min. • The active and abundant O and N sites were responsible for Pb(II) adsorption. Lacunary polyoxometalates (LPOMs), showing merits of designable coordination sites, may offer tremendous potential in toxic Pb(II) capture. However, their utilization is limited by their solubility in water and difficulty in reuse. Here, we report a self-assemble strategy to encapsulate LPOMs in customized cavities of ZIFs to afford reusable LPOM@ZIF adsorbents, with vacant oxygen sites tuned to afford efficient Pb(II) adsorption. It exhibited outstanding capture capacity of 764 mg g−1, extraordinary affinity with K d of 2.87 × 107 mg L−1, and ultrarapid efficiency with h of 412.5 mg g−1 min−1 that could enable ultradeep water purification from 71770 ppb to 1.84 ppb within 15 min. Density functional theory calculation and experiments validated the contribution of oxygen in LPOMs on this impressive Pb(II) adsorption followed μ 1 O > μ 2 O > μ 3 O, and NH on ZIFs was another site. Outcomes thus reveal LPOM@ZIF is an appealing platform for ultradeep Pb(II) removal that could address the most urgent global health challenges. [ABSTRACT FROM AUTHOR]

Adsorption and separation behaviors of ethane/ethylene on ZIF-3, -6, -8 and -10 with different topologies were studied combining Grand canonical Monte Carlo (GCMC) simulations and the ideal adsorbed solution theory (IAST). The simulated single component isotherms indicate that ZIF-3 with the smallest pore size (8.02 Å) has the highest adsorption capacity for pure ethane (4.15 mmol/g) and ethylene (2.74 mmol/g) at a low pressure of 30 kPa because of the strongest adsorption affinity. While the capacity of ZIF-6 and ZIF-10 exceed that of ZIF-3 as the pressure increased due to their large volume and accessible surface, suggesting the adsorption behaviors of ZIFs are strongly affected by ZIF topology. In the case of ethane/ethylene separation, ZIF-3 has the highest ethane selectivity of 4.79 at 1 kPa because of its greatest adsorption affinity with ethane, while ZIF-10 possesses the highest ethane selectivity of 1.75 at 8000 kPa resulted from its largest pore volume, showing cooperative and competitive effects of adsorption on ethane selectivity in low and high pressure ranges, respectively. Moreover, although ethane selectivity shows dependence on total gas pressure and ethane concentration, the ZIF topology is still the key factor dominating ethane selectivity over ZIFs. This work can be beneficial to the selection of topological structures of ZIFs in the separation of industrial paraffin/olefin mixtures. [ABSTRACT FROM AUTHOR]

Due to various characteristics properties lead(II) metal is utilized in many applications like lead ion batteries, water pipes, ammunition and paints. For this reason, concentration of lead(II) ions in water is increasing days by days which is alarming for water pollution. Water pollution is a major problem worldwide which affects biosphere badly, and causes continuous reduction of accessible sources of fresh water and ground water, available for drinking purpose. From these pollutants lead is highly toxic metal which badly affects humans as well as aquatic organisms. Due to its toxic and non-degradable nature, it is listed in top ten hazardous metals. Various adsorbents are applied for removal of lead from water. Recently, Zeolitic Imidazolate Frameworks a subclass of Metal Organic Frameworks introduced by Yaghi group having outstanding stability and porosity are applied for removal of lead from water using adsorption method as reported in many studies. In this review recent progresses for removal of lead from water by adsorption method using ZIF-8 and ZIF-67 MOFs are discussed in detail. Adsorption mechanism includes electrostatic/coordination interactions, π-π-stacking and ion exchange method for lead removal from aqueous medium are discussed in detail. Pseudo 2nd order-equation and Langmuir model are well fitted for elucidation of adsorption mechanism for lead removal. [Display omitted] • We discuss the sources, chemistry and toxicity of lead species in water systems. • Adsorption method for the removal of lead are presented with improved and enhanced efficiency. • The need and potential of ZIFs as adsorbent have been indicated for the said purpose. • ZIFs are sustainable in terms of economics, reusability and ecofriendly environment. • Thereby, some key areas have also been highlighted for further research in this domain. [ABSTRACT FROM AUTHOR]

[Display omitted] • Multi-layered Co 3 O 4 /ZnO catalysts were designed and used for CO 2 hydrogenation. • CO 2 conversion of ZnO@Co 3 O 4 was 30 times higher than that of the Co 3 O 4 @ZnO. • CO 2 conversion of ZnO@Co 3 O 4 @ZnO was higher than that of ZnO@Co 3 O 4 (35% vs 25%). • Spatial position and interfacial area of Co 3 O 4 /ZnO are key to catalytic activity. • DRIFTS showed that formate and methoxy species were the crucial intermediates. Controlled fabrication of spatial positions of different active sites on catalyst structures is critical to exploring the reaction mechanisms for CO 2 hydrogenation. Herein, two isomorphous zeolitic imidazolate frameworks (ZIF-67 and ZIF-8) were used as sacrificial templates to synthesize multi-layered Co 3 O 4 /ZnO catalysts with tunable core-shell structures and well-controlled spatial positions. The multi-layered catalysts were then evaluated for the catalytic performance for CO 2 hydrogenation. A series of characterization techniques were applied to investigate the morphology and structure of the Co 3 O 4 /ZnO composites with different spatial locations. Due to the unique multi-layered structure, the distinct interfacial structures, and the synergistic effects, the resultant core-shell structured Co 3 O 4 /ZnO nanocatalysts exhibited significantly enhanced activity as compared to their monometallic counterparts (pure Co 3 O 4 and ZnO). In addition, the ZnO@Co 3 O 4 with Co 3 O 4 as shell showed significantly higher CO 2 conversion (25%) than that of Co 3 O 4 @ZnO with ZnO as shell (0.82%). Furthermore, in-situ Diffuse Reflection Fourier Transform Infrared Spectroscopy (DRIFTS) analysis suggested that formate (HCOO*) and methoxy (CH 3 O*) species were the crucial intermediates in the CO 2 hydrogenation over the Co 3 O 4 /ZnO composite nanocatalysts. However, pure ZnO could not activate the CO 2 ; consequently, the use of the Co 3 O 4 /ZnO nanocatalysts derived from multiple-layered ZIFs structures provides new insights into improving the catalytic efficiency of CO 2 hydrogenation. [ABSTRACT FROM AUTHOR]

Abstract: Zeolitic imidazolate frameworks (ZIFs) are promising materials for advanced membrane applications due to their desirable properties, which enable them to recognize specific target molecules based on the molecular sieving mechanism and/or adsorption affinity. However, their large scale commercial applications still remain a challenge because of the absence of a synthesis method that offers reproducibility, scalability, and cost-effectiveness. To this end, here we report our work of synthesizing supported zeolitic imidazolate framework ZIF-7 films and membranes in a facile and time-efficient manner at ambient pressure using a simple electrospray deposition technique. A governing parameter which dominantly affected the microstructures and crystal integrity of the membranes was deposition temperature while precursor flow rate and applied voltage to the precursor solution were important variables to obtain a stable spraying mode which is essential to have a uniform coating. Our method, which is an electrostatic force-assisted coating approach, has the following attractive advantages over conventional synthetic routes such as in situ and secondary growth methods: (1) dramatic reduction in synthesis time and precursor consumption, (2) simplification in the activation process, and (3) potential scalability. Furthermore, the membranes obtained under optimized conditions outperformed previously reported ZIF-7 membranes for H2/CO2 separation while showing rather noticeable improvement in H2 permeance which is roughly 4–10 times higher than the previous counterparts. [Copyright &y& Elsevier]

Global warming leading to adverse climate changes has become a serious concern worldwide. Carbon capture through various technologies like adsorption has been found to be the most potential tool to address this phenomenon. In this work, novel, cost effective and green adsorbents like Zeolitic Imidazolate Frameworks (ZIFs) have been developed through simple protocols to give higher capture capacity and cyclic stability. Addressing global warming and mitigating climate change would provide the most conducive environment and ecosystem to promote efficiency, sustainability, and cleaner production in various processes. Also, carbon dioxide captured may be converted to clean fuels like Hydrogen through methanation. In this study, two bimetallic ZIFs, ((Ce,Zn)ZIF-8 and (Ce,Co)ZIF-67), were synthesized and chosen to compare with each other in terms of CC (Carbon Capture) performance. Response Surface Methodology (RSM), specifically Central Composite Design (CCD), was employed to aid in designing the carbon capture (CC) experiments. Four process parameters that influenced the CC performance were temperature, amount of adsorbent loaded, time of carbonation and effect of diethanolamine (DEA) loading. Both adsorbents showed good initial CC values with (Ce,Zn)ZIF-8 showing the better uptake value of 3.77 mmol/g than the uptake value of 3.55 mmol/g of (Ce,Co)ZIF-67. The highest absolute CC value of 4.55 mmol/g was given by 15% DEA loaded (Ce,Zn)ZIF-8 adsorbent. Temperature and DEA loading were the two most influential factors in CC uptake values, while the time of carbonation and amount of adsorbent had minimal effect individually. The pseudo-second-order and Avrami models best explained the CO 2 uptake of (Ce,Zn)ZIF-8 and (Ce,Co)ZIF-67, respectively. Langmuir adsorption isotherm suited the experimental data well indicating a monolayer adsorption process. Both the adsorbents performed decently well when subjected to the cyclic adsorption process retaining up to 94% of their initial CO 2 uptake over 15 cycles. • RSM CCD model was employed to optimize the CC experimental design. • Temperature and DEA loading were found to be most influencing on the CC uptake. • (Ce,Zn)ZIF-8 performed well giving an uptake value of 3.71 mmol/g. • Pseudo second order and Avrami models effectively fit the adsorption behaviour. • Both adsorbents showed around 95% cyclic retention. [ABSTRACT FROM AUTHOR]

An effective strategy was developed to control molecular space configurations and ZIFs' growth on PAN nanofibers precisely. ZIFs' size was controlled by regulating pH and N elemens' coordination environment. Molecular space configurations were controlled by N elemens' coordination environment. And the well-designed catalyst was applied on the oxidation of toluene. [Display omitted] • A new strategy was proposed to control ZIFs' growth on PAN precisely. • N elements coordination microenvironment could effectively control the molecular space configurations of Co complexes. • The TEA-induced Co 3 O 4 generated more octahedral structure, which is beneficial for the catalytic oxidation of VOCs. Selective exposure of dominant molecular space configurations and controllable synthesis of nanocomposites microstructure are full of challenge in improving the catalyst activity and designing materials. Herein, we precisely designed the size of ZIFs growing on nanofibers by changing the distribution of surface N elements. N elements microenvironment of nanofibers surface influenced not only ZIFs' growth mechanism, but also its derivatives' molecular space configurations (octahedral and tetrahedral structure of Co 3 O 4). To verify the influence of N element on space configurations, DFT were used to investigate structure preference energy (SPE). The result showed that the TEA (triethylamine)-induced method showed a big difference between octahedral and tetrahedral structure, indicating that this method was easier to generate octahedral complexes. Its derived Co 3 O 4 catalysts with more Co3+ spieces showed the best catalytic performance (T 90 only 220 °C). Based on this, exposure of molecular space configurations will no longer be random but manipulable. The establishment of this new strategy will play an important role in the future catalyst design and realize the adjustable and controllable catalyst. [ABSTRACT FROM AUTHOR]

Abstract: A multiscale approach is used to investigate the hydrogen adsorption in nanoporous Zeolite Imidazolate Frameworks (ZIFs) on varying geometries and organic linkers. Ab initio calculations are performed at the MP2 level to obtain correct interaction energies between hydrogen molecules and the ZIF structures. Subsequently, classical grand canonical Monte-Carlo (GCMC) simulations are carried out to obtain the hydrogen uptake of ZIFs at different thermodynamic conditions of pressure and temperature. [Copyright &y& Elsevier]

• Co nanoparticles embedded N -doped hierarchical porous carbon matrix (Co@h-ZIF) were prepared. • Co@h-ZIF-800 exhibited more excellent oxygen reduction (ORR) performance than commercial Pt/C. • Maintained channels for O 2 transport and efficient utilization of active sites facilitated ORR. Co based catalysts are the promising substitutes for Pt/C catalysts in oxygen reduction reaction (ORR). However, designing efficient Co based catalysts still remains a challenge due to many restrictions including charge transfer, mass transport and utilization of active sites, etc. Herein, Co nanoparticles embedded 3D-interconnected hierarchical porous (macro/meso/microporous) carbon matrixes with carbon nanotubes as building blocks (marked as Co@h-ZIF-800) were prepared. The prepared Co@h-ZIF-800 showed fast charge transfer and maintained the channels for continuous O 2 transport. High surface area and efficient utilization of active sites also made Co@h-ZIF-800 exhibited excellent ORR performance with half-wave potential of 0.906 V (vs. RHE), 26 mV positive than commercial Pt/C. Our work can provide an effective strategy to explore efficient Co based electrocatalysts with hierarchical structure. [ABSTRACT FROM AUTHOR]

• The adsorption/separation of various gases on ZIF-68 and −69 are identified. • ZIF-68 can store more gas than ZIF-69 due to its large pore and high surface area. • The –Cl functionalization in the ZIF-69 make it superior for gas separation. • The electrostatic behaviour of –Cl induces the gas separation in ZIF-69. • ZIF-69 selectively adsorbs CH 4 and thus can be applied in natural gas purification. Zeolitic Imidazolate Frameworks (ZIFs), which is a sub-class of MOF has been evolving as a potential candidate in adsorption, storage and separation of environmental hazardous gases. In this work, ZIF-68 and ZIF-69 structures were analyzed using Grand Canonical Monte Carlo (GCMC) simulations for their selective gas uptake for the natural gas purification and industrial separation. A suitable force field is selected in order to predict the exact experimental outcomes. It is found that the single –Cl functionalization in the organic linker of ZIF-69 has greater inductive effect, which dictates the interactions of gas molecules at the confinement. The predicted interactions directly correlate with the heat of adsorption and selectivity. This study infers that ZIF-68 will work as a gas storage material whereas ZIF-69 works as an excellent candidate for selective capture of methane from natural gas and industrial pollutants. [ABSTRACT FROM AUTHOR]

[Display omitted] 3D polyhedral Fe-doped Co 3 O 4 nanoparticles derived from FeCo-based ZIF-67 are synthesized using a facile co-precipitation method followed by two-step heat treatment and exhibit excellent OER performance with a comparably low overpotential and outstanding long-term stability in alkaline media. • Defect-rich Fe-doped Co 3 O 4 nanoparticles were synthesized using bimetallic-organic framework. • The synergistic effect of Fe doping and oxygen vacancy led to excellent OER activity. • Defect-rich Fe-doped Co 3 O 4 indicated low overpotential and outstanding durability. Herein, oxygen-deficient Fe-doped Co 3 O 4 polyhedral nanoparticles derived from FeCo‐based bimetal–organic frameworks are prepared for the electrocatalytic oxygen evolution reaction (OER) via a facile self‐templating strategy. A well-defined rhombic dodecahedral structure with abundant oxygen vacancies was constructed based on the coprecipitation, carbonization, oxidation, and partial reduction process. The proposed synthetic method is effective for fabricating a bimetallic hierarchical structure with a rough surface and a moderately controlled electronic structure, which significantly facilitates charge and mass transfer and appropriately exposes the active sites for efficient electrocatalysis. Subsequently, the as-obtained defect-rich Fe-doped Co 3 O 4 nanoparticles was found to be a superior OER electrocatalyst, with a small overpotential of 318 mV required for a current density of 10 mA cm−2, a low Tafel slope of 76.8 mV dec−1, a turnover frequency of 0.1553 s−1 at an overpotential of 370 mV, and outstanding long-term durability in 1.0 M KOH. The proposed strategy will offer a new approach in the design and development of electrochemically active non-noble materials as advanced catalysts for various energy storage and conversion applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • The bonding energy between linkers and hexane isomers are obtained by DFT calculation. • Binary mixtures hexane isomers separation in ZIFs and UiO-66-R are examined for the first time. • Monte Carlo simulations effectively reproduce adsorption isotherm in ZIFs and UiO-66-R. • ZIF-78 and ZIF-81 can separate n -alkanes from hexane isomers mixtures. • UiO-66-NH 2 and UiO-66-OH can separate double-branched alkanes efficiently. Density functional theory (DFT) calculations and molecular simulation methods were combined to investigate the adsorption behaviors of two kinds of MOF materials: ZIFs and UiO-66-R. The factors affecting the adsorption performance were analyzed and the MOF materials with excellent adsorption performance were screened out. It is found that the differences of organic ligands affect the electronic properties and steric hindrance of the materials, thus significantly affecting the adsorption selectivity and adsorption capacity. The calculation results show that ZIF-78 and ZIF-81 have the ability to preferentially separate n -hexane from a mixture of C6 isomers, and the selectivity factor of 3MP over nHEX is 6; UiO-66-NH 2 and UiO-66-OH have the ability to preferentially separate the di-branched alkanes in the adsorption separation of the mixed components, and the selectivity factor of 22DMB over nHEX is 15. [ABSTRACT FROM AUTHOR]

• The synthesis strategies of ZIFs are briefly introduced and summarized. • Batch experiment, spectral analysis and DFT are used to explore mechanisms. • The mechanisms mainly ascribe to coordination and electrostatic interaction. • Large SSA and sufficient functional groups endow ZIFs excellent performance. • Multi-factor influences demonstrate the practical application potential of ZIFs. With the rapid economic globalization and energy development, heavy metal ions/radionuclides are inevitably discharged into aqueous system and cause pollution, which seriously endanger human health and environmental sustainability. In recent years, zeolitic imidazolate frameworks (ZIFs) with huge specific surface area, excellent pore structure and abundant surface functional groups show great potential in the elimination of heavy metal ions/radionuclides. This review systematically summarizes the research progress of ZIFs and ZIF-based materials for capturing heavy metal ions/radionuclides. Firstly, the preparation and modification of ZIF-based materials are briefly introduced. Then, the removal behaviors and possible interaction mechanisms between ZIF-based materials and pollutants are explored through macro-batch experiments, micro-spectroscopy analyses and theoretical calculations. In addition, the partition coefficient as evaluation indicator was employed to objectively compare the removal performance of ZIFs and other commonly used traditional adsorbents for heavy metal ions/radionuclides. Finally, the challenges and prospects of ZIF materials in environmental governance are briefly discussed so as to provide references for future research and practical applications. [ABSTRACT FROM AUTHOR]