•Zeolitic imidazolate frameworks (ZIFs) with different dimensions were synthesized.•The electrochemical performance of ZIFs is dimensional-dependent.•One-dimensional ZIF performs best owing to the ...morphological and textural merits.
So far, direct utilization of zeolitic imidazolate frameworks (ZIFs) as the electrode materials for high-performance supercapacitors (SCs) is challenging owing to their poor electrochemical performance. However, for the first time, the electrochemical activities of ZIFs are found to be dimensional dependent in this study, and can be greatly boosted by reducing the dimension from three-dimension (3D) or two-dimension (2D) to one-dimension (1D). The unique 1D architecture endows 1D ZIF with improved conductivity as well as a high surface-to-volume ratio to facilitate the accessibility of electrolyte ions. Additionally, 1D ZIF is highly defective with abundant linker-missing defects, leading to the favorable exposure of cobalt ions as the redox active sites responsible for pseudocapacitance. Benefiting from these structural and textural merits, 1D ZIF exhibits a much higher charge storage capacity, rate capability and cycling stability than 2D and 3D ZIF. When assembled with activated carbon (AC), the asymmetric supercapacitor device (1D ZIF//AC) can deliver an impressive energy density of 76 Wh kg−1 at a power density of 800 W kg−1, superior to many other ZIFs, ZIF-based composites, ZIF-derived carbon, and even some advanced metal compounds reported in literature.
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Metal organic frameworks (MOFs) are regarded as the promising potential photocatalytic materials because of its high specific surface area, regular morphology and highly adjustable structure. Herein, ...introducing different addition percentage of 1-vinylimidazole to two-dimensional zeolite imidazole framework (ZIF-L) with leaf-shaped morphology was successfully prepared via water-assisted strategy and applied in the photocatalytic hydrogen evolution experiments. The results indicate that VZ-12 shows the highest photocatalytic activity with hydrogen production rate of 162.7 μmol g−1 h−1, which is 3 times than that in VZ-0 (pure ZIF-L, 56.33 μmol g−1 h−1) under simulated sunlight. The enhanced performance is ascribed to the increased specific surface area observed via BET, narrow band gap (Eg) explored through UV–vis DRS and decreased recombination of photo-generated charge carriers measured by photoluminescence (PL). In a word, the effort of our study provides a new idea for developing and fabricating efficient hydrogen production photocatalyst via water splitting.
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•Introducing 1-vinylimidazole to ZIF-L lattice realizes the transformation from ZIF-L phase to ZIF-8 phase.•Suitable addition of 1-vinylimidazole acquires the higher specific surface area and provides the more active sites for photocatalysis.•Different organic ligands complexing with Zn2+ narrow the band gap and reduce the recombination of photo-generated charge carriers.•1-vinylimidazole modified ZIF-L exhibits strong hydrogen evolution performance.
The conversion of crystalline metal–organic frameworks (MOFs) into metal compounds/carbon hybrid nanocomposites via pyrolysis provides a promising solution to design electrocatalysts for ...electrochemical water splitting. However, pyrolyzing MOFs generally involves a complex high‐temperature treatment, which can destroy the coordinated surroundings within MOFs, and as a result not taking their full advantage of their electrolysis properties. Herein, a simple and room‐temperature boronization strategy is developed to convert nickel zeolite imidazolate framework (Ni‐ZIF) nanorods into ultrathin Ni‐ZIF/NiB nanosheets with abundant crystalline–amorphous phase boundaries. The combined experiment, and theoretical calculation results disclose that the ultrathin thickness allows fast electron transfer and ensures increased exposure of surface coordinatively unsaturated active sites while the crystalline–amorphous interface elaborately changes the potential‐determining step to energetically favorable intermediates. As a result, Ni‐ZIF/NiB nanosheets supported on nickel foam (NF) require overpotentials of 67 mV for the hydrogen evolution reaction and 234 mV for the oxygen evolution reaction to achieve a current density of 10 mA cm−2. Remarkably, Ni‐ZIF/NiB@NF as a bifunctional electrocatalyst for overall water splitting enables an alkaline electrolyzer with 10 mA cm−2 at an ultralow cell voltage of 1.54 V. The present work may open a new avenue to the design of MOF‐derived composites for electrocatalysis.
A simple and room‐temperature boronization strategy has been developed to convert nickel zeolite imidazolate frameworks into ultrathin nanosheets with abundant crystalline–amorphous phase boundaries. Benefiting from more exposure of active sites, accelerated charge transfer ability and an optimal adsorption energy change of intermediates, the nanosheets supported on nickel foam exhibit an exceptional electrocatalytic activity towards overall water splitting.
Derived from a ZIF-L-Co nanoflake array, porous Ni-Co layered double hydroxide nanoflake array was successfully synthesized at room temperature. Due to the specific structure, such Ni-Co LDH-NFA ...exhibits outstanding electrochemical property as a battery-type electrode. In addition, the assembled asymmetric supercapacitor device shows high power density and energy density.
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In view of the complicated synthesis procedures of metallic layered double hydroxides (LDHs) in general preparation, we here report a facile route for synthesizing porous nickel-cobalt layered double hydroxide nanoflake array (Ni-Co LDH-NFA) on nickel foam on the base of our previously reported leaf-like Co-containing zeolitic imidazolate framworks (ZIF-L-Co). The ZIF-L-Co nanoflake array (ZIF-NFA) is first grown on nickel foam, which serves as a sacrificial template to synthesize Ni-Co LDH-NFA when it reacts with nickel nitrate at room temperature. The as-prepared Ni-Co LDH-NFA could be directly used as battery-type electrodes without polymer binder. Due to the highly ordered layered crystal structure of LDH and the well-defined porous nanostructure of nanoflake array, such Ni-Co LDH-NFA electrode exhibits outstanding specific capacity of 894Cg−1 at a current density of 2Ag−1. In addition, an assembled asymmetric supercapacitor device also exhibits excellent specific energy density of 48.6Whkg−1 at a specific power density of 1700Wkg−1. Even at a high power density of 17kWkg−1, the device could still remain an energy density of 18.5Whkg−1.
In this study, highly efficient and low-cost oxygen reduction reaction (ORR) catalyst is essential to improve the cost competitiveness of the proton-exchange membrane fuel cells (PEMFCs). One ...potential approach of cost reduction is to apply low loading Pt over a catalytically active support made of platinum metal group free (PGM-free) material to compensate the overall ORR activity through synergistic catalysis between Pt and PGM-free support. In this report, we investigated a series of catalysts prepared by adding low-loading Pt over ORR active support prepared through thermally activated Co/Zn methyl-imidazolate framework (Co/Zn-ZIF) at various Co/Zn ratios. Catalytic activity measurement and structural characterization were performed in an attempt to gain better understanding of certain structural factors that could influence the catalytic performance.
Because the pollutants produced by human activities have destroyed the ecological balance of natural water environment, and caused severe impact on human life safety and environmental security. Hence ...the task of water environment restoration is imminent. Metal-organic frameworks (MOFs), structured from organic ligands and inorganic metal ions, are notable for their outstanding crystallinity, diverse structures, large surface areas, adsorption performance, and excellent component tunability. The water stability of MOFs is a key requisite for their possible actual applications in separation, catalysis, adsorption, and other water environment remediation areas because it is necessary to safeguard the integrity of the material structure during utilization. In this article, we comprehensively review state-of-the-art research progress on the promising potential of MOFs as excellent nanomaterials to remove contaminants from the water environment. Firstly, the fundamental characteristics and preparation methods of several typical water-stable MOFs include UiO, MIL, and ZIF are introduced. Then, the removal property and mechanism of heavy metal ions, radionuclide contaminants, drugs, and organic dyes by different MOFs were compared. Finally, the application prospect of MOFs in pollutant remediation prospected. In this review, the synthesis methods and application in water pollutant removal are explored, which provide ways toward the effective use of water-stable MOFs in materials design and environmental remediation.
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•The synthesis strategies of water-stable MOFs are briefly introduced.•The mechanisms mainly ascribe to coordination and electrostatic interaction.•Sufficient functional groups endow MOFs excellent performance.•Multi-factor influences demonstrate the practical application potential of MOFs.
Currently, antibiotics and heavy metal contaminants have posed a great threat for ecological security and human health. Herein, the lanthanide functionalized ZIF (named ZIF-90-PABA-Eu) is constructed ...by coordinating with Eu3+ via p-aminobenzoic acid intermediate. Due to the excellent fluorescence properties, the novel fluorescent probe can selectively monitor flumequine based on “turn on” mode. Furthermore, the obtained new material (named ZIF-90-PABA-Eu-Flu) can be used as “turn off” sensor for selective detection of both radioactive and nonradioactive heavy metal ions (UO22+, Ni2+ and Cu2+) which are the main component of nuclear industrial wastewater. ZIF-90-PABA-Eu-Flu shows ultra-short fluorescence response time (3 s) and ultra-low limit of detection (9.0 × 10−3, 1.3 × 10−2 and 6.1 × 10−4 ppm) for three metal ions, which may be attributed to its good affinity with UO22+, Ni2+ and Cu2+. Moreover, principal component analysis (PCA) is applied to distinguish the three metal ions. Additionally, the possible sensing mechanism is investigated by the UV–vis spectra, luminescence lifetimes and theoretical calculation analysis. Based on these results, ZIF-90-PABA-Eu possesses promising potential in practical application and provides insight for the design of novel probes to continuously monitor flumequine, radioactive and nonradioactive heavy metal ions.
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•The lanthanide functionalized ZIF (named ZIF-90-PABA-Eu) by post-modification.•The novel fluorescent probe selectively monitor flumequine based on “turn on” mode.•Simultaneously monitor radioactive metal ions (UO22+) and nonradioactive metal ions (Ni2+ and Cu2+).•Ultra-short fluorescence response time and ultra-low limit of detection for three metal ions.•Principal component analysis (PCA) applied to distinguish various quinolones and three metal ions.
The structure design and atomic modulation of catalysts are two sides of the same coin, both of which are deemed critical factors to regulate the intrinsic electrocatalytic activity. Herein, cobalt ...single‐atom anchored on nitrogen‐doped graphene‐sheet@tube (CoSAs‐NGST) is derived from a novel Co, Zn‐coordinated zeolitic imidazolate framework (CoZn‐ZIF) in the presence of dicyandiamide. CoSAs‐NGST exhibited a hybrid structure with a bamboo‐like graphene tube and sheet. The atomic configuration of intrinsic defects is characterized by electron energy loss spectroscopy. The morphology differentiation from cake‐shape structure to low‐dimension hybrid not only enhances the dispersity of single atoms but also induces defect state evolution, which results in the formation of a CoN4‐rich graphene tube. Density functional theory (DFT) modeling revealed that the coupling effect on oxygen reduction reaction and oxygen evolution reaction (ORR/OER) pathways of Co‐N4‐tube and Co‐N4‐sheet is responsible for the enhanced activity of CoSAs‐NGST. In addition to the superb ORR/OER bifunctional catalytic performance, CoSAs‐NGST also demonstrates a notably small charge–discharge voltage drop of 0.93 V when applied in the rechargeable zinc–air battery outperforming Pt/C + RuO2 catalyst. The present study provides an insight into the relationship between the structure design and atomic modulation of the carbon based catalysts.
CoSAs‐NGST is derived from a novel edge‐rich CoZn‐ZIF. The continuous structure differentiation from bulk to low‐dimension hybrid induces electric structure evolution simultaneously. A coupling effect on the reaction pathway of oxygen reduction reaction and oxygen evolution reaction is confirmed. A CoSAs‐NGST based zinc–air battery demonstrates superior performance compared with that of Pt/C + RuO2 catalyst.
Potassium ion batteries (KIB) have become a compelling energy‐storage system owing to their cost effectiveness and the high abundance of potassium in comparison with lithium. However, its practical ...applications have been thwarted by a series of challenges, including marked volume expansion and sluggish reaction kinetics caused by the large radius of potassium ions. In line with this, the exploration of reliable anode materials affording high electrical conductivity, sufficient active sites, and structural robustness is the key. The synthesis of ZIF‐8@ZIF‐67 derived nitrogen‐doped porous carbon confined CoP polyhedron architectures (NC@CoP/NC) to function as innovative KIB anode materials is reported. Such composites enable an outstanding rate performance to harvest a capacity of ≈200 mAh g−1 at 2000 mA g−1. Additionally, a high cycling stability can be gained by maintaining a high capacity retention of 93% after 100 cycles at 100 mA g−1. Furthermore, the potassium ion storage mechanism of the NC@CoP/NC anode is systematically probed through theoretical simulations and experimental characterization. This contribution may offer an innovative and feasible route of emerging anode design toward high performance KIBs.
ZIF‐8@ZIF‐67 derived nitrogen‐doped carbon confined CoP polyhedrons (NC@CoP/NC) are employed as an innovative potassium ion battery (KIB) anode material. Batteries fabricated using this material exhibit a high cycling stability (capacity retention of 93% after 100 cycles at 100 mA g−1) and an outstanding rate performance (≈200 mAh g−1 at 2000 mA g−1).
•The ZIF derivative is prepared via a facile pyrolysis approach.•The attenuation mechanism of the enhanced EMW absorption performance is revealed.•The polarization behavior is analyzed by simulating ...the electric field.•The composite nanotubes exhibit high-efficiency EMW absorption performance.
Developing materials with a rational design of constituent and microstructure for excellent electromagnetic wave (EMW) absorption performance has been a puzzle for researchers. Herein, a type of zeolitic-imidazolate framework (ZIF-67) derivative embedded boron carbonitride (BCN) nanocomposites with a tubular microstructure are prepared via a simple, facile, scalable pyrolysis approach. The presence of BCN nanotube not only optimizes the impedance matching, but also promotes the dispersion of the Co nanoparticles, contributing to a high-efficiency utilization of conductive and magnetic losses of the ZIF derivative. Furthermore, the nanocomposites contain abundant heterogeneous interfaces, resulting in a high interfacial polarization capability, which is further confirmed by theoretical simulations. Consequently, BCN/C/Co composite nanotubes display superior EMW absorption properties. BCN/C/Co nanocomposites show a minimum reflection loss of − 56.7 dB at 12.4 GHz and an effective absorption bandwidth of 5.5 GHz at a thickness of 2.6 mm. This work thus provides a reliable reference for preparing lightweight, high-performance EMW absorbers.
