•The removal of organic pollutants using ZIF-based materials from have been reviewed.•The performance of ZIF-based materials has been extensively evaluated.•The mechanisms and the impact of key ...operational factors have been highlighted.•The key limitations and obstacles still faced by the process have been discussed.•Proposals for future research to address the unresolved challenges are included.
Zeolitic imidazolate frameworks (ZIFs) and their composites have emerged recently as attractive tools for several applications including wastewater decontamination. The interest in ZIF-based materials stems from their attractive structural, morphological, and multifunctional characteristics. Despite the good number of published research articles on the synthesis and utilization of ZIF-based materials for water decontamination, comprehensive reviews dedicated to the applications of ZIFs and their composites for the adsorptive removal of organic pollutants are still greatly lacking. Therefore, the key aim of the current article is to comprehensively review recent studies (mostly published in the past five years) on the adsorptive removal of organic pollutants from wastewater using ZIF-based materials. Synthesis approaches of ZIFs and their composites are reviewed first in order to provide insights into the progress in the synthetic protocols. Then, the adsorption performance of ZIF-based materials towards organic pollutants, their adsorption isotherms and kinetics, the effects of process parameters, and adsorption mechanisms are critically and thoroughly analyzed. Remaining knowledge gaps, limitations, and obstacles are highlighted and future work to tackle them has been proposed. Accordingly, this article provides a comprehensive state-of-the-art review of the different aspects of the application of ZIF-based materials for the adsorptive removal of organic pollutants from wastewater.
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•CoNi-LDH with a hierarchical hollow cage structure has been synthesized.•Two-step water-assisted coprecipitation method is utilized at room temperature.•The synergic effect of nickel ...nitrate adsorption on bimetallic CoNi-ZIF is optimized.•The assembled ASC supercapacitor device delivers excellent energy density, power density and cyclic stability.
Single imidazolate framework-67 (ZIF-67) is commonly used as a template to prepare layered double hydroxides (LDHs) with specific morphology to improve the performance of materials. Herein, the Co2+ ion in ZIF-67 is partially substituted by Ni2+ to obtain the dodecahedron bimetallic imidazolate framework (CoNi-ZIF). Subsequently, using bimetallic CoNi-ZIF as the sacrificial template, CoNi-LDH hierarchical hollow cage structures with wrinkled nanosheet arrays are synthesized at room temperature and in aqueous solution by an inexpensive and environment friendly surfactant-free approach. The optimized etched CoNi-LDH4 has a maximum specific capacitance of 1877 F g−1 at a current density of 1 A g−1, and cycling stability of 99.89% after 5000 cycles, which is significantly better than that of ZIF-67 derived CoNi-LDH67 (1357 F g−1 at 1 A g−1, cycling stability of 73.35%). The asymmetric supercapacitor with CoNi-LDH4 as a cathode and activated carbon (AC) as anode has an energy density of 49.3 Wh kg−1 at 750 W kg−1 power output and stable cycling performance (capacity retention of 92.13% after 5000 cycles). This study shows the prospect of bimetallic CoNi-ZIF derived LDHs nanostructures prepared at room temperature and in aqueous solution to improve the performance and stability of supercapacitors.
•Fe-ZIF-derived hollow porous carbon nanofibers were successfully fabricated.•Fe-HPCNFs achieved a maximum RL of −46.9 dB at 2.0 GHz, an effective absorption bandwidth of 3 GHz with thickness of ...2.0 mm.•Fe-HPCNFs were hierarchical porous and self-supported, with uniformly dispersed Fe single atoms.
The nanomaterials with multiple components and various heterogeneous interfaces have been considered as preferred efficient electromagnetic wave (EMW) absorbers. In this paper, Fe atoms were bonded to a zeolitic imidazole framework (Fe-ZIF) and Fe-ZIF-derived hollow porous carbon nanofibers (Fe-HPCNFs) were prepared by the microfluid electrospinning method. The EMW absorption properties of carbon nanofibers (CNFs), Fe-ZIF-derived carbon nanofibers (Fe-CNFs), and Fe-ZIF-derived hollow porous carbon nanofibers (Fe-HPCNFs) were systematically studied. The results showed that Fe-HPCNFs has the best performance, when the thickness was only 2.0 mm, the Fe-HPCNFs achieved a minimum RL loss of −46.9 dB at 17.38 GHz, with an effective absorption bandwidth of 3 GHz. The Fe-HPCNF is a flexible, ultralightweight, self-supported material as a potential high-efficiency EMW absorber.
Zeolitic imidazolate frameworks (ZIFs) are a subclass of metal-organic frameworks (MOFs). In this work, the nickel titanate (NiTiO3) nanoparticles and ZIF based nickel titanate (ZIF@NiTiO3) were ...prepared by sol-gel method and were characterized by powder X-Ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), Scanning Electron Microscopy (SEM) and BET(Brunauer-Emmett-Teller) methods. The NiTiO3 had rhombohedral crystal structure and crystallite size of 40−50 nm. FTIR confirmed of composite and metal-oxide NiO and TiO bands. BET analysis showed ZIF@NiTiO3 nanocomposite had higher surface area (345 m2 g−1) than NiTiO3 (31 m2 g−1). The adsorption studies of Pb(II) by NiTiO3 and ZIF@NiTiO3 nanocomposite were carried out by batch method. The effects of varying parameters like contact time; pH and mass of sorbent on Pb(II) were investigated. The ZIF@NiTiO3 was found to follow by pseudo second order kinetic model better than the pseudo-first order (k2 = 1.3 × 10 -2), since the adsorption isotherm experimental data was fitted better by Langmuir model than Freundlich and Temkin models. The maximum adsorption capacity of Pb(II) for NiTiO3 and ZIF@NiTiO3 was observed 72 and 155 mg g−1, respectively at pH 5. ZIF@NiTiO3 acts as sufficient reusable sorbent for Pb(II).
Zeolitic imidazolate frameworks (ZIFs) possess inherent advantages such as high specific surface area, abundant pore structures, tunable morphologies, and remarkable versatility, making them a ...popular choice as precursors for the synthesis of advanced electrocatalysts. Recent efforts to identify cost-effective oxygen electrocatalysts for rechargeable Zn-air batteries have propelled ZIF derivatives to the forefront, owing to their flexible electronic structures and chemical versatility. In this review, we systematically summarize the recent advancements in ZIF-derived oxygen electrocatalysts specifically designed for rechargeable Zn-air batteries. We focus on the potential applications of these derived materials, particularly ZIF-based composites, supported metal materials, metallic compound/carbon materials, and single-atom catalysts. Furthermore, we explore enhancements in catalytic performance through strategies aimed at improving the intrinsic activity of individual active sites, increasing the number of active sites, enhancing electrical conductivity, and boosting electron transport. Additionally, we summarize the roles of composites in oxygen electrocatalytic reactions, along with the corresponding reaction pathways and mechanisms.
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•ZIF-derived materials show great advantages when used as electrocatalysts.•Recent progress about the ZIF-derived catalysts for ZABs is summarized.•Various ZIF derivates as advanced catalysts for ORR and OER is discussed.•The perspective of the further deployment of ZIF-derived catalysts is highlighted.
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Fossil fuel has empowered a remarkable era of prosperity and development of the welfare of human society. However, the resulting large anthropogenic CO2 emissions had an adverse ...impact on global temperature. Furthermore, the scarcity of limited fossil fuel resources will eventually force them to look for alternative carbon sources to sustain a sustainable economy. Chemical fixation of CO2 into fuels and valuable chemicals via renewable energy sources has been attracting human society for not only alleviating CO2 emissions but also reducing reliance on non-renewable energy sources and minimizing the impact on the environment from displaced fossil fuel fractions. Cyclic carbonate is a valuable CO2 product that can be used as aprotic solvent, the electrolytic solvent in lithium batteries, degreasing solvents, and intermediates for the synthesis of polycarbonates, drugs, and cosmetics. It can be synthesized via cycloaddition of CO2 with epoxide under the catalytic condition due to the low reactivity of CO2 (thermodynamic as well as kinetic inert). An ideal catalyst for this conversion is composed of a Lewis acid to activate the epoxide ring and a Lewis base to open the epoxide ring. Efforts have been done to synthesize various catalytic systems for cyclic carbonate formation. The review is focused on metal-catalyzed cyclic carbonate formation. It begins with carbon capturing, storage, and utilization (CCSU) along with the importance of cyclic carbonate. The mechanism for cyclic carbonate formation was classified into two categories including binary and bifunctional systems based on the presence of nucleophilic moiety either as a separate entity or attached to a catalyst. Various metal catalysts such as metal salen, metal porphyrin, metal salts, metal–organic framework, and zeolitic imidazolate framework are discussed with recent progress in the development. It was believed that homogeneous catalysts showed high catalytic activity but difficult product separation whereas heterogeneous catalysts can be easily separated by simple filtration. Finally, the conclusion and the future outlook in the development of catalysts for cyclic carbonate formation are mentioned.
Design and construction of low‐cost electrocatalysts with high catalytic activity and long‐term stability is a challenging task in the field of catalysis. Metal‐organic frameworks (MOF) are promising ...candidates as precursor materials in the development of highly efficient electrocatalysts for energy conversion and storage applications. This review starts with a summary of basic concepts and key evaluation parameters involved in the electrochemical water‐splitting reaction. Then, different synthesis approaches reported for the cobalt‐based Zeolitic imidazolate framework (ZIF‐67) and its derivatives are critically reviewed. Additionally, several strategies employed to enhance the electrocatalytic activity and stability of ZIF‐67‐based electrocatalysts are discussed in detail. The present review provides a succinct insight into the ZIF‐67 and its derivatives (oxides, hydroxides, sulfides, selenides, phosphide, nitrides, telluride, heteroatom/metal‐doped carbon, noble metal‐supported ZIF‐67 derivatives) reported for oxygen evolution reaction (OER), hydrogen evolution reaction (HER), and overall water splitting applications. Finally, this review concludes with the associated challenges and the perspectives on developing the best economic, durable electrocatalytic materials.
MOF‐derived electrocatalysts/electrodes have excellent prospects in energy storage and conversion systems. This paper presents an in‐depth review of the application of ZIF‐67‐derived electrocatalysts for OER, HER, and overall water splitting, highlighting experimental and computational results demonstrated in the literature. Recent progress in synthesis routes and strategies used to enhance the electrocatalytic activity of ZIF‐67 derived electrocatalysts is explicitly discussed.
Heterostructure nanorods are constructed by interconnected NiSe2 and CoSe2 nanoparticles based on cone-like ZIF-L. Due to the design of the granular nanorod arrays structure, the hierarchical ...flexible nanoarrays reflect rich redox active sites, outstanding capacitance performance and excellent structural stability.
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•The one-dimensional (Ni, Co)Se2 nanoarrays based on cone-like ZIF-L were successfully designed.•A single nanorod is composed of interconnected NiSe2 and CoSe2 nanoparticles.•Due to the design of granular heterostructure, the hierarchical flexible nanoarrays reflect rich redox active sites.•The hybrid supercapacitor of CF@(Ni,Co)Se2//AC achieves an excellent electrochemical property.
The construction of heterostructure could enhance the electron transfer efficiency and increase the number of active sites, which can further develop high-performance electrode materials of supercapacitors. Herein, (Ni, Co)Se2 nanorod arrays were prepared based on the NiCo-LDH derived from a conical ZIF-L. Significantly, the single nanorod is composed of interconnected NiSe2 and CoSe2 nanoparticles, the heterostructure can expose higher conductivity, more sufficient redox reaction active sites and larger specific surface area. The as-obtained CF@(Ni, Co)Se2 achieved a high specific capacity of 188.8 mAh g−1 at the current density of 1.0 A g−1 and an outstanding cycling stability with a high capacity retention of 90% after 8000 cycles. Finally, an hybrid supercapacitor device composed of activated carbon (AC) as negative electrode and CF@(Ni, Co)Se2 as positive electrode was designed, which revealed an ideal voltage window of 0–1.6 V and exhibited a great energy density of 36.02 Wh kg−1 at the power density of 800 W kg−1, such surpassing energy storage characteristics evidently testify that (Ni, Co)Se2 nanorod arrays can be as the potential electrode material to promote the development of high-performance supercapacitors.
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•Unusual role of graphene oxide on the 2D ZIF-Co-L morphology was demonstrated.•Shape transition from leaf-like to hexagon-like ZIF-Co-L variant, by tweaking GO content.•Graphene ...oxide serves as a water regulator in the ZIF-Co-L reaction mixture.•ZIF@GO-derived Co-NC@rGO catalyst exhibited superior HER activity.•RGO content influences the HER activity despite the shape benefits of ZIF@GO precursor.
Designing unique metal–organic framework (MOF) precursors is crucial for the development of efficient metal-supported carbon-based electrocatalysts for the hydrogen evolution reaction (HER). Herein, the atypical role of graphene oxide (GO) in the morphology of 2D Co-based leaf-like zeolitic imidazolate framework (ZIF-Co-L) is reported. We demonstrated that GO regulated water accessibility in the ZIF reaction medium. The shape of GO-modified ZIF transformed from typical leaf-like (at GO contents of less than 40 wt%) to elongated hexagonal-shape (at GO contents of ≥ 40 wt%). This was attributed to the trapping of water molecules into the interlayers of GO. The water-deficient medium restricted crystal growth along the a direction of ZIF-Co-L and caused the formation of hexagonal shapes by distorting the water-driven hydrogen-bonding interactions between monodentate methylimidazole (mIm) in the ab direction and free mIm in the c direction. Furthermore, the leaf-like ZIF-Co-L@10%GO and hexagonal-shaped ZIF-Co-L@40%GO precursors were carbonized to Co-embedded N-doped-carbon/reduced GO (rGO) electrocatalysts, denoted as Co-NC@10rGO-leaf and Co-NC@40rGO-Hex, respectively. The Co-NC@10rGO-leaf catalyst (~3% rGO) presented fast kinetics and high durability (~10 h) in KOH electrolyte. Moreover, the overpotential of Co-NC@10rGO-leaf at 10 mA cm−2 in the KOH electrolyte (220 mV) was lower than that of Co-NC@40rGO-Hex. (230 mV). This was ascribed to the lower ratio of Co-to-rGO contents in the Co-NC@40rGO-Hex. (~13% rGO) inhibiting its HER activity despite their excellent shape benefits of the ZIF precursor. The superior performance of Co-NC@rGO electrocatalysts was attributed to the unique shape features of ZIF precursor; abundant active sites; and synergistic effect of Co nanoparticles, N doping, and conducting carbon. The proposed synthesis approach offers promising prospects for the development of transition-metal-supported carbon-based catalysts from shape-variant MOF precursors for efficient electrochemical water splitting.
•Material concentrations of UiO-66, MIL-88B and ZIF-8 have similar impact on cytotoxicity with respect to gene delivery.•ZIF-8 possessed the highest gene loading (nearly 90%) capacity; UiO-66 and ...MIL-88B did not demonstrate gene loading under physiologically favourable conditions.•Gene loading with ZIF-8 fully retained gene functional activity.•ZIF-8 is a biologically neutral gene delivery material with minimal changes to basal cellular metabolism.•Lack of apparent immunotoxicity of gene@ZIF-8 – no overexpression of cytokines; suppression of inflammation promoting cytokine IL8, along with normal expression of anti-inflammatory cytokine IL10.
Metal-organic frameworks (MOFs) are an emerging group of nanomaterials for successful biomedical applications in gene therapy. The most commonly biocompatible MOFs are zinc-based ZIFs, zirconium-based UiOs, and iron-based MILs. However, despite increasing applications, a comparative study to underscore the critical factors for determining effective gene delivery by such MOFs is lacking. Herein, we evaluate the potential of UiO-66 and MIL-88B and ZIF-8 for gene therapeutics delivery; revealing the comparative importance of ZIF-8. Cytotoxicity assays proved insufficient for selecting the ideal gene delivery MOF vehicle. Synthesis conditions such as ability of the MOF scaffold to envelop the gene during in-situ synthesis, post-treatment such as washing, and gene loading efficiency proved to be the critical factors in determining the favourable MOF from the material selection perspective. Rapid in-situ synthesis under physiological conditions, successful gene loading, and low concentration requirements favour ZIF MOFs as gene delivery vehicles. Impact on cellular physiology, metabolism, and architecture revealed neutrality of the delivery system; and relative effects on pro-inflammatory and anti-inflammatory cytokines suggest immunomodulatory impact.
