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The rapid and sensitive detection of 2,6-pyridinedicarboxylic acid (DPA), one of the main biomarkers of Bacillus anthracis, is of great significance for the screening and diagnosing of anthrax. Herein, a ratiometric fluorescent nanoprobe based on zeolite imidazolate framework-8 (ZIF-8)@AuNCs-Tb was constructed by embedding both gold nanoclusters (AuNCs) and terbium ions (Tb3+) into ZIF-8 for high-resolution visual detection of DPA. Due to the aggregation induced emission enhancement (AIE) effect, AuNCs embedded in ZIF-8 emit a strong orange fluorescence. When Tb3+ is coordinated with DPA added to the nanoprobe, it will emit a strong green fluorescence owing to the antenna effect. The results reveal that ZIF-8@AuNCs-Tb nanoprobe can detect DPA effectively with a good linear relationship in the range of 40–200 and 200–1000 μmol/L, the limit of detection (LOD) is estimated at 1.8 μmol/L (3σ/k). The proposed nanoprobe shows a remarkable selectivity for DPA and is quite easy to realize visualization based on the fluorescent color changing from orange to green, which has potential application in clinical diagnosis. The feasibility of this method was verified by standard addition recovery experiments simulating the release of DPA from spores.

Nitrous oxide (N2O) is a greenhouse gas (GHG) mainly issued from agriculture and waste management activities. Since N2O has a global warming potential 298 times higher than CO2 and an annual emission equivalent to 5.1 % v/v of total GHG emissions, the control of its emissions becomes essential. One of the main challenges to control N2O emissions is to capture them under the main sources’ conditions, i.e. atmospheric pressure and ambient temperature. The available technologies to control N2O emissions operate presently at medium/high pressure, being high energy consuming. The development of new and specific adsorbents for capturing N2O is important. Molecular modeling is a helpful tool to develop engineered adsorbents, generating virtual molecular interactions as a prior adsorbate-adsorbent system before experimental studies. Zeolitic Imidazolate Framework-8 (ZIF-8) has been selected in this study as an adsorbent because of its easy and reproducible synthesis, thermal stability, flexible structure, hydrophobicity and high adsorption capacity of gases, including GHGs. In the present study, the interactions between N2O and ZIF-8 were studied by molecular modeling methods, PM6 and DFT. Optimized geometries of N2O and ZIF-8, adsorption energy and ligand point length parameters were analyzed as part of a physical adsorption process. Three adsorption sites were identified on the four-membered and six-membered windows of ZIF-8. The two possible N2O interaction configurations (–ONN and –NNO) were simulated and compared in order to determine the most probable behavior of N2O. The study showed that the –ONN configuration produces more stable interactions with ZIF-8 than –NNO configuration. The six-membered window of ZIF-8 seems to be the pore where the most stable interactions occur based on the adsorption energy and the approach distance. The present study was concentrated on the interactions of one N2O molecule and a fragment of the ZIF-8, and it will be the basis for molecular dynamics simulations of adsorption with a control volume, containing several N2O molecules and a representative surface of ZIF-8 under different pressures and temperatures.

The development of non-precious based oxygen reduction reaction (ORR) catalysts with outstanding catalytic performance is desirable but still a grand challenge for practical Al-air battery. Herein, we report a vulcanization-assisted pyrolysis strategy for creating zeolitic imidazolate framework-derived catalysts with a N, S co-doped carbon support and highly exposed ZnS and Zn-Nx sites. The trithiocyanuric acid (TCA) is found not only to introduce S into the carbon derived from ZIF-8 and ZnS to adjust the electronic structure of carbon matrix during the pyrolysis, but also result in a shrinkage of carbon framework with a hierarchical porous structure. Such an architecture boosts abundant active sites exposed and accelerates remote mass transportation. As a result, the optimized 3.5ZnS/NSC-NaCl-900 delivers an impressive enhanced performance toward ORR in alkaline medium with a high half-wave potential of 0.905 V (vs. reversible hydrogen electrode), which is superior to most of non-precious metal-based catalysts. Density functional theory calculations unveil that the ZnS in 3.5ZnS/NSC-NaCl-900 can effectively lower the Gibbs energy barrier of crucial steps and therefore promotes the reaction kinetics. Furthermore, 3.5ZnS/NSC-NaCl-900 also displays greater power density and specific capacity than Pt/C in Al-air batteries.

Metal–organic frameworks (MOFs), with large specific surface area and tunable porosity, have gained lots of attention for immobilizing enzymes. However, the intrinsic open channels of most reported MOFs are generally smaller than 2 nm, which significantly prevents the passage of enzymes, and the diffusion efficiency of substrates and products. Here we report a new hierarchical micro-mesoporous zeolitic imidazolate framework-8 (ZIF-8) with core-shell superstructure (HZIF-8) using colloidal hydrated zinc sulfate (ZnSO4•7H2O) as a soft template for enzyme immobilization. The ZnSO4•7H2O forms an aggregation of colloids due to the self-conglobation effect in methanol, which affords a soft template for the formation of HZIF-8. Cytochrome C (Cyt C) was immobilized in interior of HZIF-8 through entrapment during the formation of HZIF-8. The resultant immobilized Cyt C (Cyt C@HZIF-8) exhibited 4-fold and 3-fold higher activity than free Cyt C and Cyt C encapsulated in conventional microporous ZIF-8 (Cyt C@ZIF-8), respectively. Meanwhile, the Km value of Cyt C@HZIF-8 significantly decreased due to the presence of mesopores compared with Cyt C@ZIF-8, indicating enhanced substrate affinity. After 7 cycles, Cyt C@HZIF-8 still maintained 70% of its initial activity whereas Cyt C@ZIF-8 only retained 10% of its initial activity. Moreover, the obtained HZIF-8 showed outstanding performance in co-immobilization of multi-enzyme for the detection of glucose.

Carbon materials hold the great promise for application in energy storage devices owing to their low cost, high thermal/chemical stability, and high electrical conductivity. However, it remains challenging to synthesize high-performance carbon electrodes in a simple, scalable and sustainable way. Here, we report a facile method for scalable synthesis of porous carbon anode by using cheap and easily accessible zeolitic imidazolate framework-8 as a template and polyvinylpyrrolidone as an additional carbon source. The obtained porous carbon shows the macroscopic sheet-like morphology, which has the highly disordered structure, expanded interlayer spacing, abundant pore structure, and nitrogen doping properties. This porous carbon anode is demonstrated to have the excellent K+ charge storage properties in specific capacity, rate capability, and cycling stability. A potassium-ion capacitor assembled by using this porous carbon as the anode, delivers a maximum energy density of 85.12 Wh/kg and power density of 11860 W/kg as well as long cycle life exceeding 3000 cycles. This represents a critical advance in the design of low cost and scalable carbon material for applications in energy storage devices.

Low-cost, stable, and highly active electrocatalysts for oxygen reduction reaction (ORR), especially for pH-universal ORR, are vital for developing numerous renewable energy devices. Herein, a hierarchical N, S-codoped porous carbon-based catalyst (ZFP-800) coupled with abundant FeS/ZnS heterojunctions was facilely prepared via direct pyrolysis of a Ferrocene-crosslinked pyrrole hydrogel composited with zeolitic imidazolate framework-8 (ZIF-8) templates. Compared with the heterojunction-free catalytic activity, the ZFP-800 catalytic activity was significantly higher in pH-universal ranges. Moreover, the ZFP-800 exhibited competitive ORR performance to commercial Pt/C (20%) in various electrolytes, in terms of onset (Eonset), half-wave potentials (E1/2), limiting current density (JL), durability, and methanol immunity. For instance, it exhibited super ORR catalytic activity on Eonset and E1/2, and exceeded that of the benchmark Pt/C in both the alkaline and neutral media. Furthermore, the application of ZFP-800 as a cathode catalyst in a home-made Zn–air battery demonstrated its operation capability in ambient conditions with a competitive performance on the specific energy density (828 mA·h·gZn–1), maximum discharge power density (205.6 mW·cm−2), rate performance, and the long-term stability (188 h at 5 mA·cm−2). This study can facilitate the development of advanced heterojunction-based materials for renewable energy applications.

Colorimetric biosensors, based on enzyme-like nanomaterials, have come into the spotlight in virtue of their visual detection. Herein, a daisy-like zeolitic imidazolate framework-67/reduced grapheme oxide (ZIF-67/rGO) nanozyme with unique 3D hierarchical structures has been designed to realize visual detection of hydrogen peroxide (H2O2) that is recognized as a strong oxidizing agent or reactive oxygen species associated with oxidative stress in biological systems. The daisy-like ZIF-67/rGO is prepared by a facile one-step liquid-phase method conducted under room temperature. The successful introduction of rGO endows the daisy-like ZIF-67/rGO nanozyme with abundant porous structure, high specific surface area, and good charge transfer capability, which significantly accelerates the adsorbability and recognition towards the substrates and the oxidation rate of TMB-H2O2 reaction, and thus improving the nanozyme activity observably. It is conductive to nanozyme-modulated H2O2 determination. The established colorimetric biosensor platform based on ZIF-67/rGO nanozyme exhibits remarkable sensitivity and high specificity for the application in visual detection of H2O2. The detection limit of ZIF-67/rGO-based biosensor platform is as low as 3.81 μM, which is nearly 8 times lower than that of ZIF-67-based biosensor platform. Moreover, its potential applicability as an ideal platform for colorimetric biosensors is demonstrated by testing the concentration of H2O2 in milk samples, which sheds light on the promising application of the proposed biosensing system in point-of-care detection.

Designing and constructing advanced heterojunction architectures are desirable for boosting CO2 photoreduction performance of semiconductor photocatalysts. Herein, we have prepared hierarchical ZnS@ZnIn2S4 core-shell cages with controlled particle sizes using sequential synthesis of Zeolitic imidazolate (ZIF-8) polyhedrons, ZnS cages, and ZnIn2S4 nanosheets on the ZnS polyhedron cages. ZIF-8 polyhedrons are firstly synthesized by a liquid-phase approach. The subsequent sulfidation of the ZIF-8 polyhedrons results in the formation of ZnS polyhedron cages, which act as substrates for fabricating ZnS@ZnIn2S4 core-shell cages by growing ZnIn2S4 nanosheets. The size of ZnS cages can be tuned to optimize CO2 photoreduction performance of hierarchical ZnS@ZnIn2S4 core-shell cages. The synergy of the unique hierarchical core-shell cage-like structure and heterojunction composition endows the hybrid catalyst high incident light utilization, abundant active sites, and effective separation of photoexcited charge carriers. Benefiting from these advantages, the optimized hierarchical ZnS@ZnIn2S4 core-shell cages exhibit enhanced performance for CO2 photoreduction with the CO yield of 87.43 μmol h−1g−1 and 84.3% selectivity, which are much superior to those of single ZnIn2S4 or ZnS. Upon Au decoration, the CO2 photoreduction performance of ZnS@ZnIn2S4 core-shell cages is further enhanced because of the Schottky junctions and surface plasmon resonance effect.

In this study, we are the first to observe the alignment behaviors of various assembling molecules with different feature sizes and shapes, including rod-, disc-, and column-shaped molecules, on zeolitic imidazolate framework-8 (ZIF-8) surfaces. Among the various rod-shaped 4-alkyl-4′-cyanobiphenyls (nCBs), those with short alkyl chains with less than nine hydrocarbons (e.g., 5CB, 6CB, 8CB, and 9CB) were vertically aligned on the ZIF-8 surface, while nCBs with long alkyl chains with more than 10 hydrocarbons (e.g., 10CB and 11CB) were randomly oriented on the surface. Unlike rod-shaped small molecules, the disc- and column-shaped molecules were randomly oriented on the ZIF-8 surface. A molecular dynamic simulation revealed that the vertical alignment of rod-shaped molecules on the ZIF-8 surface can be attributed to physical anchoring by the ZIF-8 micropores. Most portions of the alkyl chain of nCB with shorter alkyl chain lengths (n ≤ 9) can be inserted into the ZIF-8 aperture, while nCBs with longer alkyl chain lengths (n > 9) cannot be adequately anchored in the ZIF-8 aperture. According to these results, we believe that MOF materials with micropores can offer an effective tool for controlling the orientation of various functional small molecules.

Porous ionic liquids (PILs), with permanent porosity and fluidity, have been drawing great attention in theoretical research and application. Herein, a novel PIL (HPMo@ZIF-8-PIL) was fabricated by dispersing a phosphomolybdic acid-modified zeolitic imidazolate framework-8 (ZIF-8) into an ionic liquid for deep reactive extraction desulfurization. Size calculation results show that 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonylimide) ([Emim][NTf2]) with larger ion sizes cannot occupy pores of ZIF-8. In detail, the structure along with permanent porosity was well characterized by gas absorption and molecule displacement experiments, and it was found that HPMo@ZIF-8-PIL can not only promote the dispersion of the catalytically active sites but also retain the good liquidity and excellent extraction ability of ionic liquids. At room temperature, 100% removal of dibenzothiophene sulfur in a model oil could be achieved within 2 h using HPMo@ZIF-8-PIL and hydrogen peroxide as the catalyst and oxidant, respectively. Besides, the successful preservation of porosity increases the probability of contact between the oxidant and active sites, which is also in favor of the promotion of desulfurization performance. This work offers a new method for the modification of porous frameworks to construct PIL catalysts, which will provide a new insight into the application of PILs.

In recent years, Co, N co-doped carbon (Co–N–C) materials as oxygen reduction reaction (ORR) catalysts have attracted great attention because of their good ORR stability as well as decent activity. Co-doped zeolitic imidazolate framework-8 (Co@ZIF-8) as the precursor for synthesizing Co–N–C has attracted great interest recently. Co@ZIF-8 synthesis method may affect the properties of the as-synthesized Co@ZIF-8 precursors, which will surely affect the properties and ORR performance of Co@ZIF-8-derived Co–N–C catalysts. Herein, three methods, viz. room-temperature stirring method, reflux method, and hydrothermal method, were used to synthesize Co@ZIF-8 precursors. Physical characterization shows that the synthesis method has a great influence on the textural properties, composition, and graphitization degree of the as-synthesized Co–N–C catalysts. Electrochemical characterization shows that Co–N–C-R synthesized with reflux method exhibits an onset potential (Eonset) of 0.905 V, a half-wave potential (E1/2) of 0.792 V and a limiting current density (JL) of 5.85 mA cm−2 in acidic media, which are higher than those of Co–N–C–S (Eonset = 0.870 V, E1/2 = 0.770 V, JL = 4.71 mA cm−2) and Co–N–C–H (Eonset = 0.892 V, E1/2 = 0.785 V, JL = 4.68 mA cm−2) synthesized with room-temperature stirring method and hydrothermal method, respectively. The better ORR activity observed on Co–N–C-R can be attributed to its larger graphitization degree and larger mesopore volume. Catalytic stability test shows that Co–N–C-R has negligible activity loss after 5000 potential cycles. This work demonstrates that reflux method is a more suitable method for synthesizing Co–N–C catalysts for ORR.

Developing electrocatalysts with excellent catalytic performance and superior durability for hydrogen evolution reaction (HER) remains a challenge. Herein, metal-nitrogen sites (M–Nx, M = Ni and Cu) are successfully implanted into zeolitic imidazolate zinc framework (ZIF-8)-derived nitrogen-doped porous carbon (ZIF/NC) to prepare Ni-ZIF/NC and Cu-ZIF/NC electrocatalysts for the HER. These M–Nx active sites significantly enhanced the electrocatalytic activities of Ni-ZIF/NC and Cu-ZIF/NC. Metal Ni acted as a catalyst for catalysis of Ni-ZIF/NC to form carbon nanotubes-like structures, which provided convenient ion transmission pathways. Owing to its special morphology and an increased number of defects, Ni-ZIF/NC displayed superior electrocatalytic activity in the HER compared to those of Cu-ZIF/NC and ZIF/NC. In an alkaline environment, Ni-ZIF/NC exhibited an overpotential at the current density of 10 mA cm−2 (η10) of 163.0 mV and Tafel slope of 85.0 mV dec−1, demonstrating an electrocatalytic property equivalent to that of Pt/C. In an acidic environment, Ni-ZIF/NC yielded a η10 of 177.4 mV and Tafel slope of 83.9 mV dec−1, which were comparable to those of 20 wt.% Pt/C. Moreover, Ni-ZIF/NC and Cu-ZIF/NC also exhibited superior stabilities in alkaline environments. This work offers a valuable strategy for controlling the morphology and implanting M–Nx active sites into carbon for designing novel catalysts for use in alternative new energy applications.

Due to the serious recombination of electron-hole and weak photoresponse ability, achieving highly efficient photoelectrochemical (PEC) water splitting activity for TiO2 photoelectrode has become a key issue. In this paper, we reported a new method for preparing ZnO/TiO2 photoelectrodes by electrostatic adsorption from zeolitic imidazolate framework-8 (ZIF-8) as the precursor. ZIF-8 was combined with TiO2 nanorods (NRs) through electrostatic interaction and then calcined to obtain ZnO/TiO2 heterojunction photoelectrodes with abundant oxygen vacancies (Ovac). The introduced ZnO with Ovac provides a large number of active sites which enhanced the electrical conductivity and charges separation of ZnO/TiO2 photoelectrode. The optimal photocurrent density of ZnO/TiO2 photoelectrodes at 1.23 V versus (vs.) reversible hydrogen electrode (RHE) under illumination (100 mW/cm2) has reached 1.76 mA/cm2, almost 2.75 times that of the pure TiO2. Meanwhile, the incident photon-to-electron conversion efficiency (IPCE) of the best photoelectrode has increased to 58.2% at 390 nm, the charge injection (ηinjection) and separation (ηseparation) efficiency have reached to 93.53% and 51.62% (1.23 V vs. RHE), respectively.

Excessive use of pesticides in modern agriculture results in large amounts of pesticide residues in agricultural production, greatly threatening human health. Herein, novel two-dimensional leaf-like zeolitic imidazolate framework-L decorated with multi-walled carbon nanotubes (MWCNTs/ZIF-L) was prepared by a facile solvent way and exploited as electrode material for sensitive electrochemical sensing of thiabendazole (TBZ). Two-dimensional ZIF-L presents high surface area, large pore volume, and abundant active sites, which exhibits high enrichment ability towards TBZ molecules, while the MWCNTs interspersed on ZIF-L can prominently enhance the electron transport capability and improve the electrocatalytic activity for TBZ oxidation. Due to the intriguing synergy between the components, the MWCNTs/ZIF-L-based electrochemical sensor reveals a limit of detection (LOD) of 6.0 nmol·L−1, which is lower than that reported in most literatures. Additionally, satisfactory reproducibility and repeatability, long-term stability, and excellent selectivity are acquired. The proposed method was also applied for the detection of TBZ in apple and orange samples with acceptable recoveries.

The electronic structures and, particularly, the nature of the HOMO in a series of PcFeL2, PcFeL'L″, and [PcFeX2]2- complexes (Pc = phthalocyaninato(2-) ligand; L = NH3, n-BuNH2, imidazole (Im), pyridine (Py), PMe3, PBu3, t-BuNC, P(OBu)3, and DMSO; L' = CO; L″ = NH3 or n-BuNH2; X = NCO-, NCS-, CN-, imidazolate (Im-), or 1,2,4-triazolate(Tz-)) were probed by electrochemical, spectroelectrochemical, and chemical oxidation as well as theoretical (density functional theory, DFT) studies. In general, energies of the metal-centered occupied orbitals in various six-coordinate iron phthalocyanine complexes correlate well with Lever Electrochemical Parameter EL and intercross the phthalocyanine-centered a1u orbital in several compounds with moderate-to-strong π-accepting axial ligands. In these cases, an oxidation of the phthalocyanine macrocycle (Pc(2-)/Pc(1-)) rather than the central metal ion (Fe(II)/Fe(III)) was theoretically predicted and experimentally confirmed.

Nucleophilic substitution of [(η5‐cyclopentadienyl)(η6‐chlorobenzene)iron(II)] hexafluorophosphate with sodium imidazolate resulted in the formation of [(η5‐cyclopentadienyl)(η6‐phenyl)iron(II)]imidazole hexafluorophosphate. The corresponding dicationic imidazolium salt, which was obtained by treating this imidazole precursor with methyl iodide, underwent cyclometallation with bis[dichlorido(η5‐1,2,3,4,5‐pentamethylcyclopentadienyl]iridium(III) in the presence of triethyl amine. The resulting bimetallic iridium(III) complex is the first example of an NHC complex bearing a cationic and cyclometallated [(η5‐cyclopentadienyl)(η6‐phenyl)iron(II)]+ substituent. As its iron(II) precursors, the bimetallic iridium(III) complex was fully characterized by means of spectroscopy, elemental analysis and single crystal X‐ray diffraction. In addition, it was investigated in a catalytic study, wherein it showed high activity in transfer hydrogenation compared to its neutral analogue having a simple phenyl instead of a cationic [(η5‐cyclopentadienyl)(η6‐phenyl)iron(II)]+ unit at the NHC ligand., Iron power: A cyclometalated Fe(II) and Ir(III) complex based on the cationic (η5‐cyclopentadienyl)(η6‐phenyl)iron(II)]imidazole skeleton is reported. Compared to its neutral analogue without the [CpFe]+ fragment, it is surprisingly active in the transfer hydrogenation of ketones. Mechanistic investigation on the reaction paths performed by DFT calculations provided a better understanding of the reaction mechanism, possible intermediates and the active species.

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.

Herein, we report a nanocellulose hydrogel that has a packaging structure for on-demand drug release. Zeolitic imidazolate frameworks-8 (ZIF-8) were grown on the surface of polydopamine (PDA) to produce PDA@ZIF-8 nanoparticles. The obtained PDA@ZIF-8 nanoparticles were then incorporated into a network of cellulose nanofibrils (CNFs) to fabricate a PDA@ZIF-8/CNFs composite hydrogel. The loading ratio of the drug tetracycline hydrochloride (TH) was 58%. A slight burst release behavior was observed at the beginning, and the composite hydrogel presented a significant pH-dependent release behavior. The drug delivery time of the PDA@ZIF-8/CNFs composite hydrogel was 3.5 times longer than that of the PDA/CNFs composite hydrogel. Furthermore, NIR light radiation accelerated the drug delivery rate. The drug release mechanism was mainly driven by anomalous transport. Importantly, the novel PDA@ZIF-8/CNFs composite hydrogel was found to be biocompatible according to in vitro cytotoxicity test. Because of its unique multiple drug release responses, the PDA@ZIF-8/CNFs composite hydrogel may be used in future clinical applications as a promising drug delivery carrier.

Proton exchange membranes from crosslinked poly(vinyl alcohol) using sulfosuccinic acid (SSA) and glutaraldehyde as double crosslinking agents were reported. The effect of SSA content on water uptake and proton conductivity was investigated. The most promising membrane was then formed into composites with zeolitic imidazolate framework-8 (ZIF-8). ZIF-8 was synthesized, and confirmed by Fourier transform infrared spectroscopy, X-ray diffraction analysis, and transmission electron microscopy. The effect of ZIF-8 loading (0–10%) on membrane properties was firstly reported. Relatively good dispersion of ZIF-8 nanoparticles was observed for composites with %loadings up to 5%. The enhancements in proton conductivity and mechanical strength were observed upon ZIF-8 addition, and the optimum loading was 5%. In an attempt to improve proton conductivity at low relative humidity, the composite was further doped with imidazole. Proton conductivity increased with increasing imidazole content and temperature, and reached a maximum of 2.3 × 10−4 S/cm at 80 °C under non-humidified condition.

ZnSe has got extensive attention for high-performance LIBs anode due to its remarkable theoretical capacity and environmental friendliness. Nevertheless, the large volume variation for the ZnSe in the discharge/charge processes brings about rapid capacity fading and poor rate performance. Herein, ZnSe/C hollow polyhedrons are successfully synthesized through selenization of zeolitic imidazolate framework-8 (ZIF-8) with resorcinol-formaldehyde (RF) coating. The protection of C layer derived from RF coating layer and Ostwald ripening during the process of selenization play important roles in promoting formation of ZnSe/C hollow polyhedrons. The ZnSe/C hollow polyhedrons exhibit good rate behavior and long-term cycle stability (345 mAh g -1 up to 1000 cycles at 1 A g -1 ) for lithium ion batteries (LIBs) anode. The improved electrochemical performance is benefit from the unique ZnSe/C hollow architecture, in which the hollow structure can effectively avoid terrible volume expansion, and the thin ZnSe/C shell can not only provide adequate diffusion paths of lithium ions and but also enhance the electronic conductivity.

Metal-organic cages, a class of supramolecular containers constructed by the self-assembly of metal ions and organic ligands, show great promise as catalytic agents. In this work, we designed and synthesized a series of rhombic dodecahedral Ni-Cu heterometal imidazolate cages (Ni8Cu6L24) that can act as highly active photo-Fenton-like catalysts. These cages possess a high ability to generate hydroxyl radicals (•OH) under visible light in the presence of H2O2, which can rapidly degrade organic pollutants (e.g., rhodamine B, methylene blue, and methyl orange) into CO2 and H2O. Besides, they are robust catalysts, with high catalytic activity and reusability under conditions in high H2O2 concentration, providing potentially advanced materials for degrading persistent organic pollutants.

Atomically dispersed metals stabilized by nitrogen elements in carbon skeleton hold great promise as alternatives for Pt-based catalysts towards oxygen reduction reaction in proton exchange membrane fuel cells. However, their widespread commercial applications are limited by complicated synthetic procedures for mass production. Herein, we are proposing a simple, green mechanochemical approach to synthesize zeolitic imidazolate frameworks precursors for the production of atomically dispersed “Fe-N4” sites in holey carbon nanosheets on a large scale. The thin porous carbon nanosheets (PCNs) with atomically dispersed “Fe-N4” moieties can be prepared in hectogram scale by directly pyrolysis of salt-sealed Fe-based zeolitic imidazolate framework-8 (Fe-ZIF-8@NaCl) precursors. The PCNs possess large specific surface area, abundant lamellar edges and rich “Fe-N4” active sites, and show superior catalytic activity towards oxygen reduction reaction in an acid electrolyte. This work provides a promising approach to cost-effective production of atomically dispersed transition metal catalysts on large scale for practical applications.

Zn/ZSM-5 was prepared by using a combinative method of steam-assisted crystallization (SAC) and hard templating. Zn-based MOFs, including coordination polymer of Oslo number 1-Zn (CPO-1-Zn) and zeolitic imidazolate framework-8 (ZIF-8), were used as the sacrificial agents. These MOFs-derived catalysts were compared with Zn/ZSM-5 made by impregnation. Physicochemical characterization revealed that all Zn/ZSM-5 catalysts had finely dispersed Zn2+ species, i.e., ZnO and Zn(OH)+. However, the concentration of Lewis acidic Zn2+ species and the compositions of Zn(OH)+ and ZnO were different. Applying ZIF-8 as the sacrificial agent generated a higher concentration of Lewis acidic Zn2+ species and a higher ratio of Zn(OH)+-to-ZnO in Zn/ZSM-5, which showed a better performance in the aromatization of methanol.

Wood is a state-of-art, renewable, and sustainable building material with excellent mechanical properties but negligible triboelectric polarizability. Strategies to improve and rationally tune the triboelectric properties of wood are needed to further its application for mechanical energy harvesting in smart buildings. We found that wood becomes more triboelectrically positive when modified by in situ-grown zeolitic imidazolate framework-8 (ZIF-8), a metal-organic framework (MOF), and more triboelectrically negative when coated with poly(dimethylsiloxane) (PDMS). A triboelectric nanogenerator (TENG) made with two radial-cut wood samples (L x R x T: 35 x 20 x 1 mm(3)), respectively functionalized with ZIF-8 and PDMS, can generate an open-circuit voltage (Voc) of 24.3 V and a short-circuit current (Isc) of 0.32 mu A upon 50 N, 80 times higher compared with that of native wood. We demonstrate the applicability of our functionalized wood TENG (FW-TENG) in smart buildings by using it to power household lamps, calculators, and electrochromic windows. ISSN:2590-2385

The more apparent specific heat release at a lower high-temperature decomposition (HTD) temperature of ammonium perchlorate (AP) poses a challenge for the development of highly active catalysts. In this work, a well-designed cobalt-embedded N-doped porous graphitized carbon (Co@NC) catalyst is obtained by high-temperature calcination of a zeolite imidazolate frameworks-67 precursor, in which the cobalt catalytic active center realizes effective nanoscale dispersion; meanwhile, the cobalt and N-doped porous graphitized carbon can release considerable heat after oxidation, and the cobalt oxides have an excellent catalytic effect on reducing the HTD temperature of AP. The catalytic activity of Co@NC was tested by a differential thermal analytical method. The results indicated that the HTD peak of AP was significantly decreased by 100.5 °C, the apparent activation energy of the HTD reaction of AP was reduced by 82.0 kJ mol-1, and the heat release compared with pure AP increased 2.9 times. On teh basis of these findings, Co@NC is expected to be one of the best candidate materials for AP thermal decomposition.

The unlimited consumption of traditional fossil fuels prompted an urgent need for the new H2 production strategies to provide green and sustainable energy resources. In this context, Co9S8 has emerged as a potent photocatalyst due to its narrow bandgap. Herein, we describe the synthesis of a recyclable lollipop-shaped Co9S8/CdS nanocomposite via direct annealing of zeolitic imidazolate framework-67 (ZIF-67) and CdS, as the template and sulfur source, respectively. The close contact of these two materials promotes the electron transfer and enhances the number of active sites toward the desired redox reaction. The special structure of Co9S8/CdS results in a high photocatalytic H2 production rate of 1852 μmol h−1 g−1 under visible-light illumination, which is ~200 times higher than that of pure ZIF-67 and Co9S8. Therefore, this study provides a new method for the preparation of Co9S8 that concomitantly improves the photocatalytic performance of pure ZIF-67 in the H2 production technology.

Hierarchically porous materials are promising as catalyst supports in fuel cells and batteries as they increase overall mass transfer and active site density. In this work, a hierarchically porous catalyst support for oxygen reduction reaction (ORR) in acidic media has been developed by a bottom-up approach. Graphene oxide (GO) was introduced during synthesis conditions of zeolitic imidazolate framework-8 (ZIF-8) to produce hybrid material of ZIF-8/GO. Successful nanocomposite formation was realized by preserved crystallinity and chemical interaction between species as revealed by X-ray diffraction and Fourier transform infrared spectroscopy. Introduction of GO and pyrolysis of resulting hybrid structure causes emergence of disordered meso/macropores with an accompanying increase in pore volume as revealed by N2 sorption experiments. Pt nanoparticle deposition on pyrolyzed hybrid material by polyol method results in electrocatalyst Pt/NC-1, which shows greatly improved mass activity (182 vs 86 A g−1Pt) and specific activity (467 vs 186 μA g−1Pt) at 0.8 V for ORR against reference electrocatalyst Pt/r-GO and improved specific activity against Pt/C.

This work focuses on an interdisciplinary issue in energy management and biosensing techniques. Aiming at enhancing the biosensing detection of dopamine at high ambient temperatures, we developed an innovative integration of phase-change microcapsules with a metal-organic framework (MOF) based on zeolitic imidazolate framework-8 to develop an intelligent electrochemical biosensing system with a thermal self-regulation function. We first fabricated a type of electroactive microcapsules containing a MOF-anchored polypyrrole/SiO2 double-layered shell and a phase-change material (PCM) core. The resultant microcapsules not only exhibit a regular spherical morphology with a layer-by-layer core-shell microstructure but also display an effective temperature-regulation capability to enhance enzymatic bioactivity under phase-change enthalpies of around 124.0 J·g-1 along with good thermal impact resistance and excellent thermal cycling stability for long-term use in thermal energy management. These electroactive microcapsules were then used to modify a working electrode together with laccase as a biocatalyst to construct a thermal self-regulatory biosensor. With a high sensitivity of 3.541 μA·L·μmol-1·cm-2 and a low detection limit of 0.0069 μmol·L-1 at 50 °C, this biosensor exhibits much better determination effectiveness toward dopamine at higher temperatures than conventional biosensors thanks to in situ thermal management derived from its PCM core in the electroactive microcapsules. This study offers a promising approach for development of intelligent thermal self-regulatory biosensors with an enhanced detection capability to identify various chemicals accurately in a wide range of applicable temperatures.

Biobutanol is one of the promising biofuels, which is produced by fermentation. The concentration of butanol in the fermentation broth does not usually reach 2% (by wt). To use biobutanol as fuel, it is necessary to purify this mixture. In this study, chitosan and sodium alginate hybrid membranes filled with zeolitic imidazolate framework-90 (ZIF-90) were synthesized and utilized for butanol dehydration by the pervaporation process. The synthesized pristine and hybrid membranes were characterized by SEM, FTIR, TGA and contact angle. The swelling resistance of the membrane was determined by sorption tests. Hybrid membranes display higher thermal and mechanical stability and swelling resistance compared to pristine membranes. The separation performance of membranes was determined through pervaporation process. The effects of ZIF loading ratio, process temperature and feed concentration on separation performance were investigated. Compared to pristine membranes, hybrid membranes were found to be more effective for dehydration of butanol by pervaporation. Among hybrid membranes, sodium alginate hybrid membranes filled with ZIF-90 displayed the best separation performance. While the highest flux and separation factor values of 0.987 kg/m2h and 1978 were obtained using sodium alginate hybrid membrane, the flux value of 0.325 kg/m2h and the separation factor value of 1124 were achieved in chitosan hybrid membrane.

Zeolitic Imidazolate Frameworks containing imidazolate-based linkers were successfully prepared into three different molar ratios 3:10, 1:1, and 10:3 mmol. The effect of 2-methylimidazole (HmIM)/ Cobalt (II) nitrate hexahydrate (Co(NO3)2·6H2O) molar ratio on the physicochemical characteristics of Co-based ZIF-67 showed that Co-ZIF-R3 has achieved the highest specific capacity of 86 C g−1 at 0.25 A g−1 in 1 M KOH. An asymmetric supercapacitor (ASC) utilising Co-ZIF-R3 as fabricated cell exhibited 32 C g−1 at current density of 0.25 A g−1 within a large working potential of 1.70 V. Furthermore, 87% of its capacity was kept after 2500 cycles at the reversible current density of 0.50 A g−1 until 1.0 A g−1 revealed its high potential as electrode material for supercapacitor. This work not only amplified the information of direct use of MOF as cathode material in supercapacitors, but also the relation of the role of Co/HmIM molar ratio on the electrode materials with good electrochemical performance.

Conforming to sustainable development trend, natural material cellulose has been extensively studied in the field of energy storage. However, its low conductivity is a huge obstacle to its application in supercapacitors. Integrating nanocellulose as a green binder with conductive materials achieves the efficient use of natural resources. Here, carbon nanotubes (CNTs) were embedded in porous Co3O4 (PCO) dodecahedrons in situ derived from zeolitic imidazolate framework-67 (ZIF-67), for which the morphologies of the composites were considerably remained at the dodecahedron. The main pseudo-capacitive materials are regulated by different amounts of CNTs to modify the morphology and enhance the conductivity. For electrode materials, the charming structure of PCO-CNTs (PCC) with multichannels allows efficient electron transfer, which brings about a competent utilization of redox active sites in PCO. What is more worth mentioning is that the nanocellulose-PCC nanocomposites with good processing properties were used to form binder-free electrodes. Given the fine designed structure and good electrochemical performance, the electrodes were assembled into symmetric supercapacitors, showing high areal capacitance, energy, and power density. The preparation of composites based on PCC and nanocellulose provides a new way to develop sustainable energy storage devices.

Designing reasonable MOFs-derived carbon materials to further effectively improve the catalytic activity toward ORR in the practical application of fuel cells is very necessary but remains a great challenge. Herein, a new facile yet robust strategy, self-sacrifice template approach combined with a variety of MOFs, to achieve core–shell ZnO@zeolitic imidazolate frameworks precursor (ZnO@ZIF-8@ZIF-67) is developed. Subsequently, the porous hybrid hollow carbon shell (Zn/Co-NC) can be obtained by calcinating the precursor. Impressively, the Zn/Co-NC-800 prepared by pyrolysis at 800 °C manifests excellent ORR performances with a positive onset potential of 1.03 V (vs. reversible hydrogen electrode) (vs. RHE), a more positive half-wave potential at 0.856 V (vs. RHE, a positive shift of 28 mV compared with the Pt/C) and 4-electron pathway (n = 3.80). Also, it performs higher long-term stability (only a 7.9% decay of initial current density after 20000 s) and better methanol tolerance in comparison with the traditional Pt/C in alkaline media. In our current work, the synthesis strategy of the self-sacrificing template combined with ZIFs opens up a new route for the preparation of highly efficient non-precious metal electrocatalysts for ORR.

Because of the importance of large-scale metal-organic framework (MOF) production and processing, the development of practical solutions to obtain commercially relevant MOF-based products is essential. Herein, we demonstrate a feasible pathway to construct functional zeolitic imidazolate framework-8 (ZIF-8)-coated fabric composite from commercially available precursors, through a scalable synthetic protocol to produce a large quantity of nanoscale ZIF-8, followed by a facile mean to drop-cast the powdered nanoparticles onto the fabric substrate. The ZIF-8/fabric composite shows enhanced organic dye adsorption capability and superior antibacterial property. This simple yet effective preparation process might be readily adopted for the large-scale production of useful MOF-based composite materials. Ministry of Education (MOE) Nanyang Technological University National Research Foundation (NRF) This research is supported by the Singapore National Research Foundation Investigatorship (Grant NRF-NRFI2018-03) and the Ministry of Education Singapore under the Academic Research Funds (Grants RT12/19 and MOE-MOET2EP10120-0003). W.L.T. is thankful for a Nanyang President’s Graduate Scholarship supporting his doctoral study.

In this work, hybrid nanocomposites rice husk derived graphene (GRHA) and zeolitic imidazolate framework-8 (ZIF-8) were prepared for hydrogen adsorption. The main contribution of this study is the simplification of the synthesized GRHA/ZIF-8 hybrid nanocomposites. Besides that, the use of synthesized graphene from rice husk (RH) could help in overcoming environmental issue since disposal of RH is rather challenging. GRHA was obtained through calcining rice husk ash (RHA) at 900 °C for 2 h in a muffle furnace at atmospheric condition while the nanocomposite of GRHA/ZIF-8 was produced in free solvent condition using deionized water at room temperature for only 1 h. The N2 adsorption-desorption indicated a type I isotherm. Interestingly, it was found that the BET specific surface area (BETSSA) of GRHA/ZIF-8 showed enhancement up to 3 times higher as compared to pristine GRHA with the addition of 0.2 g of GRHA. From the experimental data, the adsorption of H2 by nanocomposite GRHA/ZIF-8 obeyed the pseudo-second order kinetic model and intraparticle diffusion model with R2 value up to 0.9890 and 0.8087 respectively at 12 bar. Moreover, the GRHA/ZIF-8 possessed highest hydrogen adsorption of 31.84 mmol/g at 12 bar. These impressive results are justified by the combination of ZIF-8's microporosity and GRHA's mesoporosity.

A porous graphitic carbon was obtained via the pyrolysis of a zeolite imidazolate framework (ZIF-8) under Ar atmosphere. Then, the carbon was functionalized with carboxylic groups and applied for separation of neodymium ions (Nd3+) from water. The adsorbent (denoted as C-ZDC) was characterized by X-ray diffraction, N2 adsorption–desorption isotherms, infrared spectroscopy, X-ray photoelectron spectroscopy, scanning and transition electron microscopies, thermogravimetric analysis, and Boehm titration. A practical adsorption equilibrium was attained within 4 h, and the adsorption isotherm at 25 °C revealed a maximum adsorption capacity of 175 mg/g, which is one of the highest values reported for different kinds of adsorbents. The adsorption kinetics and equilibrium isotherms were modeled, and the selectivity for Nd3+ over other metal ions was examined. From the effect of solution pH on the adsorption and material characterization results before and after adsorption, the high adsorption capacity of C-ZDC was ascribed to the formation of coordination bonds between Nd3+ ions and the –COOH groups. Further, the material was reusable for at least four adsorption–desorption cycles after a simple step of acid washing.

In this work, the synthesis route and evaluation of two poly(ionic liquids) (PolyILs) derived from alkylimidazolium imidazolate to be used as corrosion inhibitors (CIs) of API 5L X52 steel exposed ...

Fundamental understanding of the dependence between the structure and composition on the electrochemical CO2 reduction reaction (CO2 RR) would guide the rational design of highly efficient and selective electrocatalysts. A major impediment to the deep reduction CO2 to multi-carbon products is the complexity of carbon-carbon bond coupling. The chemically well-defined catalysts with atomically dispersed dual-metal sites are required for these C-C coupling involved processes. Here, we developed a catalyst (BIF-102NSs) that features Cl- bridged dimer copper (Cu2 ) units, which delivers high catalytic activity and selectivity for C2 H4 . Mechanistic investigation verifies that neighboring Cu monomers not only perform as regulator for varying the reaction barrier, but also afford distinct reaction paths compared with isolated monomers, resulting in greatly improved electroreduction performance for CO2 .

A series of CdS-modified zeolitic imidazolate framework-8 (ZIF-8)-derived porous carbons (marked as CZCs) were fabricated via a facile method in the study. And, the preparation samples were further analyzed by employing some characterization technologies. Also, the introducing amounts of porous carbons were systematically investigated. The results indicated that the composite CZC600-30 presented an optimum photocatalytic activity for organic pollutant methylene blue (MB, 150 mL, 10 mg/L) or tetracycline (TC, 100 mL, 30 mg/L) degradations under visible-light irradiation and the pollutants were all able to be completely removed within 60 min. The adding amount of CZC used to degrade MB and TC was 30 and 5 mg, respectively. The occurrences of good performances were originated from the formation of type (II) heterojunction, which can efficiently separate photoinduced carriers. In addition, the introduction of the CZC increases surface area (53.3 m2 g−1) and pore volume (0.171 cm3 g−1) compared to those (27.2 m2 g−1 and 0.062 cm3 g−1) of CdS. Radical trapping measurements illustrated that radical O2− was a main active species during the photodegradation process. Analyzing results demonstrated that the material is a promising catalyst for the removals of organic pollutants.

In CO2 transformation catalysis, the synthesis of cyclic carbonates using two classes of MOF catalysts viz., zeolitic imidazolate frameworks (ZIF) and MOFs with carboxylate-capped SBUs have gained large attention. Herein we propose the strategy of employing a unified multifunctional framework formed in the metal-centered assembly of imidazole and amino-carboxylates for CO2 transformation, such as propylene carbonate (PC) by the cycloaddition of CO2 with propylene oxide. The framework {[Cu(L-asp)(1,4-bix)0.5]·3H2O}n (CuAspBix) comprises of the amino acid building units, L-aspartic acid (L-Asp) and the flexible ligand, 1,4-bis(imidazole-1-yl methyl)benzene [1,4-Bix]. The 1,4-Bix ligand with imidazole terminals renders elongated M-M distances and flexibility in comparison with pristine ZIF materials. The cumbersome synthesis procedure poor phase purity of the bulk catalyst in solvothermal conditions were improved by a microwave-assisted synthesis, preserving the structural and physicochemical properties. Minimal energy input or room temperatures for the catalysis occurred via the synergistic participation of CuAspBix and quaternary ammonium bromide salt, demonstrated by density-functional theory computational studies to propose mechanistic pathway of the reaction. Reaction conditions were optimized by altering the parameters. The heterogeneous catalyst was reused four times without a significant change in activity.

The 1,3‐bis(tricyanoborane)imidazolate anion 1 was obtained in high yield from lithium imidazolate and B(CN)3−pyridine adduct. Anion 1 is chemically very robust and thus allowed the isolation of the corresponding H5O2 + salt. Furthermore, monoanion 1 served as starting species for the novel dianionic N‐heterocyclic carbene (NHC), 1,3‐bis(tricyanoborane)imidazoline‐2‐ylidenate anion 3 that acts as ditopic ligand via the carbene center and the cyano groups at boron. First reactions of this new NHC 3 with methyl iodide, elemental selenium, and [Ni(CO)4] led to the methylated imidazolate ion 4, the dianionic selenium adduct 5, and the dianionic nickel tricarbonyl complex 6. These NHC derivatives provide a first insight into the electronic and steric properties of the dianionic NHC 3. Especially the combination of properties, such as double negative charge, different coordination sites, large buried volume and good σ‐donor and π‐acceptor ability, make NHC 3 a unique and promising ligand and building block., Unprecedentedly stable salts of the 1,3‐bis(tricyanoborane)imidazolate ion with different types of counterions were obtained on large scale. Deprotonation of the imidazolate ion provided access to the corresponding dianionic NHC that acts as ditopic ligand.

Highlights SiO2-mediated ZIF-L is developed to prepare Co–N4@2D/3D carbon.Co–N4@2D/3D integrates the advantages of 0D Co single atom and 2D/3D carbon support.Co–N4@2D/3D carbon-based sulfur cathode enables a high reversible specific capacity and low capacity fading rate. Supplementary Information The online version contains supplementary material available at 10.1007/s40820-021-00676-6., The practical application of lithium–sulfur batteries is severely hampered by the poor conductivity, polysulfide shuttle effect and sluggish reaction kinetics of sulfur cathodes. Herein, a hierarchically porous three-dimension (3D) carbon architecture assembled by cross-linked carbon leaves with implanted atomic Co–N4 has been delicately developed as an advanced sulfur host through a SiO2-mediated zeolitic imidazolate framework-L (ZIF-L) strategy. The unique 3D architectures not only provide a highly conductive network for fast electron transfer and buffer the volume change upon lithiation–delithiation process but also endow rich interface with full exposure of Co–N4 active sites to boost the lithium polysulfides adsorption and conversion. Owing to the accelerated kinetics and suppressed shuttle effect, the as-prepared sulfur cathode exhibits a superior electrochemical performance with a high reversible specific capacity of 695 mAh g−1 at 5 C and a low capacity fading rate of 0.053% per cycle over 500 cycles at 1 C. This work may provide a promising solution for the design of an advanced sulfur-based cathode toward high-performance Li–S batteries. Supplementary Information The online version contains supplementary material available at 10.1007/s40820-021-00676-6.

Metal-organic frameworks (MOF) are an emerging class of microporous materials with promising applications. MOF nanocrystals, and their assembled super-structures, can display unique properties and reactivities when compared with their bulk analogues. MOF nanostructures of 0-D, 2-D, and 3-D dimensions can be routinely obtained by controlling reaction conditions and ligand additives, while formation of 1-D MOF nanocrystals (nanowires and nanorods) and super-structures has been relatively rare. We report here a facile templated interfacial synthesis methodology for the preparation of a series of 1-D MOF nano- and micro-structures with precisely controlled shapes and sizes. Specifically, by applying track-etched polycarbonate (PCTE) membranes as the templates and at the oil/water interface, we rapidly and reproducibly synthesize zeolitic imidazolate framework-8 (ZIF-8) and ZIF-67 nano- and micro structures of sizes ranging from 10 nm to 20 μm. We also identify a size confinement effect on MOF crystal growth, which leads to single crystals under the most restricted conditions and inter-grown polycrystals at larger template pore sizes, as well as surface directing effects that influence the crystallographic preferred orientation. Our findings provide a potentially generalizable method for controlling the size, morphology, and crystal orientations of MOF nanomaterials, as well as offering fundamental understanding into MOF crystal growth mechanisms. Control over the morphology of porous materials is key for many applications, but can be challenging when targeting small particle sizes. Here one dimensional nano- and microstructures of zeolitic imidazolate frameworks are prepared using track-etched polycarbonate membranes as templates for interfacial synthesis.

The bifunctional efficient electrocatalysts for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are in urgent need for the advanced overall water splitting (OWS) device. Restricted by the thermodynamic limitations of the catalytic active center for OER and the reaction kinetics limitations induced by the structure of the electrocatalysts, the development of OWS catalysts requires more effort. Herein, a porous carbon-based bimetal electrocatalyst of Mo0.84Ni0.16-Mo2C@NC nanosphere is prepared by hydrothermal treatment of PMo12@PVP@Zn/Ni-ZIF which is synthesized via one-pot self-assembled hydrothermal method. Our study confirms that the Mo-Ni alloy and Mo2C nanoparticles homogeneously distribute in nitrogen-rich carbon-based materials. Furthermore, the porous structure exposes rich active sites and increases the effective specific area for redox reactions. The obtained Mo0.84Ni0.16-Mo2C@NC catalyst requires low overpotentials of 151 and 285 mV to reach a current density of 10 mA cm−2 towards the water reduction and oxidation in 1 M KOH solution, respectively, and possesses good catalytic stability for one day. This work introduces an advanced method for the synthesis of the bimetal electrocatalyst.

Aldol condensation of formaldehyde with dihydroxyacetone (DHA) in an aqueous medium (pH 7.54–8.71) was studied at 65–80 °C in the presence of zeolite-like zinc imidazolate frameworks based on 2-methylimidazole (ZIF-8) and 2-ethylimidazole (MAF-5 and MAF-6). Selectivity of the process was shown to depend on the pH of the reaction solution, which is controlled by the amount of catalyst in the reaction mixture, and on the reaction temperature. The reaction carried out at pH 8.36 and 80 °C leads to a high yield of С6-sugars. Erythrulose is formed with a high yield (39–60 %) at a temperature of 65 °C and pH 7.54-8.71. It was found that the yield of erythrulose in the presence of the catalytic systems under consideration depends on the pore radius and increases in the series MAF-6 > MAF-5 > ZIF-8. Advantages of the studied systems in comparison with the homogeneous and heterogeneous phosphate systems proposed in the literature were revealed.

In the present article, the synthesis of zeolite imidazole framework-11 (ZIF-11) by ultrasonic-assisted hydrothermal process and its application as an electrode modifier for electrochemical determination of uric acid in urine are demonstrated. The obtained materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and nitrogen adsorption/desorption isotherms. It was found that the ZIF-11 with rhombic dodecahedron topology and high surface area (1066 m2.g-1) was synthesized in a certain temperature and found in around 25–40°C, and other crystalline phases of zinc benzimidazolate deferring from ZIF-11 phase were found in less 25°C or higher than 40°C. The ZIF-11 is stable in the pH range 6-10. The modification of glassy carbon electrode was performed with ZIF-67 using the drop-casting procedure. The present ZIF-11 modified electrode was employed to study the electrochemical behavior of uric acid (UA). UA oxidation is catalyzed by this electrode in aqueous buffer solution (pH 7) with a decrease of 70 mV in overpotential compared to glassy carbon electrode. With the differential pulse–anodic stripping voltammetry (DP-ASV) method, the oxidation current of UA versus its concentration shows good linearity in the range 20–540μM ( R = 0.998 ) with a detection limit of 0.48 μM ( S / N = 3 ). The obtained ZIF-11 modified electrode was applied in the detection of UA content in urine samples, and satisfied results were obtained.