Applications of Metal-Organic-Framework-Derived Carbon Materials

Carbon/copper oxide electrode materials with high atomic utilization constructed by in-situ induced growth strategy of nano metal-organic frameworks

Carbon/metal composites derived from metal-organic frameworks (MOFs) have attracted widespread attention due to their excellent electronic conductivity, adjustable porosity, and outstanding stability. However, traditional synthesis methods are limited by the dense stereo geometry and large crystal grain size of MOFs, resulting in many metals active sites are buried in the carbon matrix. While the common strategy involves incorporating additional dispersed media into material, this leads to a decrease in practical metal content. In this study, nanosized copper-metal-organic frameworks (Cu-MOFs) are in-situ grown on surface of carbon spheres by pre-anchoring copper ions, and the hybrid composite of porous carbon/copper oxide with high copper atom utilization rate is prepared through activation and pyrolysis methods. This strategy effectively addresses the issue of insufficient exposure of metal sites, and the obtained composite material exhibits high effective copper atom utilization rate, large specific surface area (2052.3 m2·g-1), diverse pore structure, outstanding specific capacity (1076.5F·g-1 at 0.5 A·g-1), and excellent cycle stability. Furthermore, this highly atom-economical universal method has positive significance in application fields of catalysis, energy storage, and adsorption.

Multi-layered carbon accommodation of MnO2 enabling fast kinetics for highly stable zinc ion batteries

Large-scale durable aqueous zinc ion batteries for stationary storage are realized by spray-coating conductive PEDOT(Poly(3,4-ethylenedioxythiophene)) wrapping MnO2/carbon microspheres hybrid cathode in this work. The porous carbon microspheres with multiple layers deriving from sucrose provide suitable accommodation for MnO2 active materials, exposing more redox active sites and enhancing the contact surface between electrolyte and active materials. As a result, MnO2/microspheres are adhered to the current collector by a conductive PEDOT coating without any binder. The ternary design retards the structural degradation during cycling and shortens the electron and ion transport path, rendering the full batteries high capacity and long cycle stability. The resulting batteries perform the capacity of 277, 227, 110, 85 and 50 mAh/g at 0.2, 0.5, 1, 2 and 5 A/g, respectively. After 3000 cycles the initial capacity retains 86%, and 80% after 5000 cycles. GITT indicates PEDOT wrapping MnO2/microspheres cathode enables better ion intercalating kinetics than conventional MnO2. The work could represent a novel and significant step forward in the studies on the large-scale application of zinc ion batteries.

Facile synthesis of a carbon supported lithium iron phosphate nanocomposite cathode material from metal-organic framework for lithium-ion batteries

Lithium iron phosphate (LiFePO4, LFP) has become one of the most widely used cathode materials for lithium-ion batteries. The inferior lithium-ion diffusion rate of LFP crystals always incurs poor rate capability and unsatisfactory low-temperature performances. To meet with the requirements from the ever-growing market, it is of great significance to synthesize carbon supported LFP nanocomposite (LFP/C) cathode materials using cost effective and environmentally friendly methods. In this work, an LFP/C cathode material is straightforwardly prepared from a metal-organic framework (MOF) precursor ferric gallate (Fe-GA) using its self-template effect. The Fe-GA precursor is firstly fabricated from the redox coprecipitation reaction between Fe foils and gallic acid (GA) molecules in mild aqueous phase. Then the Fe-GA is directly converted to the LFP/C sample after a following solid-state reaction. In half-cells, the LFP/C composite exhibits a reversible capacity of 109.7 mAh·g-1 after 500 cycles under the current rate of 100 mA·g-1 at 25 °C as well as good rate capabilities. In the LFP/C//graphite full-cells, the LFP/C composite can deliver a reversible capacity of 71.4 mAh·g-1 after 50 cycles in the same condition as the half-cells. The electrochemical performances of the LFP/C cathode in half-cells at lower temperature of -10 °C are also examined. Particularly, the evolution of samples has been explored and the lithium-ion storage mechanism of the LFP/C cathode has been unveiled. The sample synthesis protocol is straightforward, eco-friendly and atomic efficient, which can be considered to have good potential for scaling-up.

Tadpole-Like Carbon Nanotube with Fe Nanoparticle Encapsulated at the Head and Zn Single-Atom Anchored on the Body: One-Pot Carbonization for Tetramodal Synergistic Cancer Therapy

Precise integration of diverse therapeutic approaches into nanomaterials is the key to the development of multimodal synergistic cancer therapy. In this work, tadpole-like carbon nanotubes with Fe nanoparticle encapsulated at the head and Zn single-atom anchored on the body (Fe@CNT-Zn) is precisely designed and facilely prepared via one-pot carbonization. In vitro studies revealed the integration of chemotherapy (CT), chemodynamic therapy (CDT), photothermal therapy (PTT), and photodynamic therapy (PDT) in Fe@CNT-Zn as well as the near-infrared light (NIR)-responsive cascade therapeutic efficacy. Furthermore, in vivo studies demonstrated the NIR-triggered cascade-amplifying synergistic cancer therapy in a B16 tumor-bearing mouse model. The results not only showcased the Fe@CNT-Zn as a potential tetramodal therapeutic platform, but also demonstrated a proof-of-concept on metal-organic framework-based "one stone for multiple birds" strategy for in situ functionalization of carbon materials.

Unveiling the scope and perspectives of MOF-derived materials for cutting-edge applications

Although synthesis and design of MOFs are crucial factors to the successful implementation of targeted applications, there is still lack of knowledge among researchers about the synthesis of MOFs and their derived composites for practical applications. For example, many researchers manipulate study results, and it has become quite difficult to quit this habit specifically among the young researchers Undoubtedly, MOFs have become an excellent class of compounds but there are many challenges associated with their improvement to attain diverse applications. It has been noted that MOF-derived materials have gained considerable interest owing to their unique chemical properties. These compounds have exhibited excellent potential in various sectors such as energy, catalysis, sensing and environmental applications. It is worth mentioning that most of the researchers rely on commercially available MOFs for use as precursor supports, but it is an unethical and wrong practice because it prevents the exploration of the hidden diversity of similar materials. The reported studies have significant gaps and flaws, they do not have enough details about the exact parameters used for the synthesis of MOFs and their derived materials. For example, many young researchers claim that MOF-based materials cannot be synthesized as per the reported instructions for large-scale implementation. In this regard, current article provides a comprehensive review of the most recent advancements in the design of MOF-derived materials. The methodologies and applications have been evaluated together with their advantages and drawbacks. Additionally, this review suggests important precautions and solutions to overcome the drawbacks associated with their preparation. Applications of MOF-derived materials in the fields of energy, catalysis, sensing and environment have been discussed. No doubt, these materials have become excellent class but there are still many challenges ahead to specify it for the targeted applications.

Structure-dependent magnetoelectric and magnetothermal effects of MOF-derived zero-valence cobalt and iron oxide nanoparticles on a carbonaceous matrix

For the first time, the dominant magnetoelectric activity of ZIF-67-derived carbonaceous microparticles embedded with Co nanoparticles and distinctive magnetothermal effect of MIL-88B-derived Fe3O4 nanocubes decorated on carbonaceous microrods, respectively, were explored to be controlled by the structure of the MOF-derived electrically conductive carbonaceous matrix and metal nanoparticles.

A tremella-like in situ synthesis of ZIF-67Co(OH)F@Co3O4 on carbon cloth as an electrode material for supercapacitors

In this study, a simple in situ technique followed by hydrothermal method is used to synthesize a novel tremella-like structure of ZIF-67Co(OH)F@Co3O4/CC metal-organic framework (MOF) derived from zeolite imidazole. The in situ synthesis of metal-organic frameworks (MOFs) increases their conductivity and produces more active sites for ion insertion. Their unique, scalable design not only provides more space to accommodate volume change but also facilitates electrolyte penetration into the electrode resulting in more active materials being utilized and ion-electron transfer occurring faster during the cycle. As a result, the binder-free ZIF-67Co(OH)F@Co3O4/CC supercapacitor electrode exhibits typical pseudo-capacitance behaviour, with a specific capacitance of 442 F g-1 and excellent long-term cycling stability of 90% after 5000 cycles at 10 A g-1.

A review on synthesis of MOF-derived carbon composites: innovations in electrochemical, environmental and electrocatalytic technologies

Carbon composites derived from Metal-Organic Frameworks (MOFs) have shown great promise as multipurpose materials for a range of electrochemical and environmental applications. Since carbon-based nanomaterials exhibit intriguing features, they have been widely exploited as catalysts or catalysts supports in the chemical industry or for energy or environmental applications. To improve the catalytic performance of carbon-based materials, high surface areas, variable porosity, and functionalization are thought to be essential. This study offers a thorough summary of the most recent developments in MOF-derived carbon composite synthesis techniques, emphasizing innovative approaches that improve the structural and functional characteristics of the materials. Their uses in electrochemical technologies, such as energy conversion and storage, and their function in environmental electrocatalysis for water splitting and pollutant degradation are also included in the debate. This review seeks to clarify the revolutionary effect of carbon composites formed from MOFs on sustainable technology solutions by analyzing current research trends and innovations, opening the door for further advancements in this rapidly evolving sector.

The N-anchoring effect in NH2-functionalized MOF-derived iron-carbon nanomaterials for oxygen reduction

The incorporation of an iron source into NH2-MOF-5, followed by thermal decomposition, yields a porous metal-carbon catalyst (MOF5A-Fe@NC). This catalyst possesses significant N content, a high degree of graphitization, and abundant Fe-Nx sites, which contribute to enhanced oxygen reduction. Specifically, the obtained MOF5A-Fe@NC demonstrates a positive onset potential (0.972 V), a substantial limiting current density (4.815 mA cm-2), and a small Tafel slope (58.7 mV dec-1), and maintains a high current retention of 96.3% after 10 hours.

Transitioning metal-organic frameworks from the laboratory to market through applied research

Metal-organic frameworks (MOFs) have captivated researchers for over 25 years, yet few have successfully transitioned to commercial markets. This Perspective elucidates the progress, challenges and opportunities in moving MOFs to market, focusing on applied research. The five applied research steps that enable technology development and demonstration are reviewed: synthesis, forming, processing (washing and activation), prototyping and compliance. Furthermore, the importance of a comprehensive techno-economic analysis incorporating a complete picture of costs and revenues is discussed. Readers can use the understanding of applied research presented herein to tackle their MOF commercialization challenges.

Cobalt and zinc nanoparticles from pyrolysis of their MOF precursors exhibiting potent organophosphorus hydrolase-mimicking activities

Cobalt and zinc nanoparticles from pyrolysis of cobalt-containing ZIF-67 and zinc-containing ZIF-90 exhibited potent organophosphorus hydrolase-mimicking activities for the hydrolysis of organophosphorus compounds within minutes at pH 9.0 and 25-40 °C. The resulting nanozymes could find potential applications in many areas such as chemical decontamination, environmental protection and defense of chemical weapons.

Computational Simulations of Metal-Organic Frameworks to Enhance Adsorption Applications

Metal-organic frameworks (MOFs), renowned for their exceptional porosity and crystalline structure, stand at the forefront of gas adsorption and separation applications. Shortly after their discovery through experimental synthesis, computational simulations quickly become an important method in broadening the use of MOFs by offering deep insights into their structural, functional, and performance properties. This review specifically addresses the pivotal role of molecular simulations in enlarging the molecular understanding of MOFs and enhancing their applications, particularly for gas adsorption. After reviewing the historical development and implementation of molecular simulation methods in the field of MOFs, high-throughput computational screening (HTCS) studies used to unlock the potential of MOFs in CO2 capture, CH4 storage, H2 storage, and water harvesting are visited and recent advancements in these adsorption applications are highlighted. The transformative impact of integrating artificial intelligence with HTCS on the prediction of MOFs' performance and directing the experimental efforts on promising materials is addressed. An outlook on current opportunities and challenges in the field to accelerate the adsorption applications of MOFs is finally provided.

Metal-organic framework based self-powered devices for human body energy harvesting

The shift from traditional bulky electronics to smart wearable devices represents a crucial trend in technological advancement. In recent years, the focus has intensified on harnessing thermal and mechanical energy from human activities to power small wearable electronics. This vision has attracted considerable attention from researchers, with an emphasis on the development of suitable materials that can efficiently convert human body energy into usable electrical form. Metal-organic frameworks (MOFs), with their unique tunable structures, large surface areas, and high porosity, emerge as a promising material category for human body energy harvesting due to their ability to be precisely engineered at the molecular level, which allows for the optimization of their properties to suit specific energy harvesting needs. This article explores the progressive development of MOF materials, highlighting their potential in the realm of self-power devices for wearable applications. It first introduces the typical energy harvesting routes that are particularly suitable for harvesting human body energy, including thermoelectric, triboelectric, and piezoelectric techniques. Then, it delves into various research advances that have demonstrated the efficacy of MOFs in capturing and converting body-generated energy into electrical energy, emphasizing on the conceptual design, device fabrication, and applications in medical health monitoring, human-computer interaction, and motion monitoring. Furthermore, it discusses potential future directions for research in MOF-based self-powered devices and outlines perspectives that could drive breakthroughs in the efficiency and practicality of these devices.

Recent Functionalized Strategies of Metal-Organic Frameworks for Anode Protection of Aqueous Zinc-Ion Battery

The inherent benefits of aqueous Zn-ion batteries (ZIBs), such as environmental friendliness, affordability, and high theoretical capacity, render them promising candidates for energy storage systems. Nevertheless, the Zn anodes of ZIBs encounter severe challenges, including dendrite formation, hydrogen evolution reaction, corrosion, and surface passivation. These would result in the infeasibility of ZIBs in practical situations. To this end, artificial interfaces with functionalized materials are crafted to protect the Zn anode. They have the capability to modulate the zinc ion flux in proximity to the electrode surface and shield it from aqueous electrolytes by leveraging either size effects or charge effects. Considering metal-organic frameworks (MOFs) with tunable pore size, chemical composition, and stable framework structures, they have emerged as effective materials for building artificial interfaces, prolonging the lifespan, and improving the unitization of Zn anode. In this review, the contributions of MOFs for protecting Zn anode, which mainly involves facilitating homogeneous nucleation, manipulating selective deposition, regulating ion and charge flux, accelerating Zn desolvation, and shielding against free water and anions are comprehensively summarized. Importantly, the future research trajectories of MOFs for the protection of the Zn anode are underscored, which may propose new perspectives on the practical Zn anode and endow the MOFs with high-value applications.

Tailoring Cu-Based Electrocatalysts for Enhanced Electrochemical CO2 Reduction to Alcohols: Structure-Selectivity Relationship

The use of CO2 as a feedstock for the production of carbon-based fuels and value-added chemicals offers a promising route toward carbon neutrality. In this study, two Cu-based electrocatalysts, namely, Cu24/N-C and Cu2/N-C, are successfully prepared by thermal treatment of Cu24 metal-organic polyhedron-loaded zeolitic imidazolate framework-8 (ZIF-8) nanocrystals (Cu24/ZIF-8) and Cu2 dinuclear compound-loaded ZIF-8 nanocrystals (Cu2/ZIF-8), respectively. Extensive structural and compositional analyses were conducted to confirm the formation of Cu nanocluster-loaded N-doped porous carbon supports in both Cu24/N-C and Cu2/N-C and Cu nanoparticles encapsulated by graphitic carbons in Cu2/N-C as well. These two Cu-based electrocatalysts exhibited different behaviors in the electrochemical CO2 reduction reaction (CO2RR). The Cu24/N-C electrocatalyst showed high selectivity for CO production, while Cu2/N-C showed a preference for alcohol generation. The excellent stability of Cu2/N-C over a 30 h continuous electrochemical reduction further highlights its potential for practical applications. The difference in electrocatalytic performance observed in the two catalysts for CO2RR was attributed to distinct catalytic sites associated with Cu nanoclusters and nanoparticles. This research reveals the significance of their structures and compositions for the development of highly selective electrocatalysts for CO2 reduction.

Synthesis and Characterization of Sodium Lignosulfonate-Based Phosphorus-Containing Intermediates and Its Composite Si-P-C Silicone-Acrylic Emulsion Coating for Flame-Retardant Plywood

Through the substitution reaction between 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and sodium lignosulfonate (LS), a novel phosphorus-containing sodium lignosulfonate (DAL) was successfully synthesized via the solvothermal method and used as a multifunctional flame retardant to prepare a novel silicone-acrylic emulsion (SAE) composite Si-P-C coating. The structure of DAL was determined by X-ray diffraction (XRD), attenuated total reflection infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), and nuclear magnetic resonance (solid-state 13C NMR and 31P NMR). The results demonstrated that incorporating an appropriate dosage of DAL (0.9 g, 1.5 wt %) into SAE-based composite coatings enhances flame retardancy and reduces heat release and smoke production during burning. The peak heat release rate (p-HRR) decreases from 236.7 to 120.3 kW·m-2, total smoke production (TSP) decreases by 71.1%, and the flame-retardant index increases from 1.00 to 4.58. Meanwhile, the coating is transformed into a dense and nonflammable vitreous polyphosphate barrier layer during the firing process to prevent heat or mass transfer. Furthermore, the pyrolysis kinetics identify that the 3D Z-L-T model governs the coatings' pyrolysis, and the appropriate DAL makes the pyrolysis Eα climb from 300.98 to 331.30 kJ·mol-1 at 358-439 °C. Hence, this study presents a new synthesis method of multifunctional flame retardant DAL, studies the excellent properties and cross-linking mechanism of DAL-doped SAE-composite Si-P-C coatings, and explores a halogen-free, low-carbon, and clean eco-technology strategy.

Conductive Metal-Organic Framework Grown on the Nickel-Based Hydroxide to Realize High-Performance Electrochemical Glucose Sensing

Glucose holds significant importance in disease diagnosis as well as beverage quality monitoring. The high-efficiency electrochemical sensor plays a crucial role in the electrochemical conversion technology. Ni(OH)2 nanosheets are provided with high specific surface area and redox activity that are widely used in electrochemistry. Conductive metal-organic frameworks (cMOFs) perfectly combine the structural controllability of organic materials with the long-range ordering of inorganic materials that possess the characteristic of high electron mobility. Based on the above considerations, the combination of Ni(OH)2 and Ni-HHTP (HHTP=2,3,6,7,10,11-hexahydroxytriphenylene) as an electrode modification material is designed to enhance electrochemical performance. In this work, to improve glucose detection, a sequence of Ni(OH)2@NiCo-HHTP and NiM-LDH@Ni-HHTP (M=Co2+, Mn2+, Cu2+, LDH=layered double hydroxide) are successfully synthesised by doping metals into Ni-HHTP and Ni(OH)2, respectively. As a result, NiCu-LDH@Ni-HHTP showed the best excellent glucose detection sensitivity.

Carbon-dots encapsulated luminescent metal-organic frameworks@surface molecularly imprinted polymer: A facile fluorescent probe for the determination of chloramphenicol

In this study, carbon dots (CDs)-encapsulated luminescent metal-organic frameworks@surface molecularly imprinted polymer (CDs@MOF@SMIP) was facilely prepared and applied as fluorescent probe for specific identification and sensitive detection of chloramphenicol (CAP) in food. Fluorescent CDs, serving as signal tags, were encapsulated within metal-organic backbones (ZIF-8), yielding luminescent MOF materials (CDs@ZIF-8). The synthesized CDs, CDs@ZIF-8 and CDs@ZIF-8@SMIP were investigated by morphological and structural characterizations (UV-Vis, XRD, FT-IR, BET, TEM). The CDs@ZIF-8@SMIP probe was demonstrated to have remarkable selectivity and sensitivity towards CAP. Its fluorescence decreased linearly with CAP concentration from 0.323 μg L-1 (0.001 μM) to 8075.0 μg L-1 (25.0 μM), featuring a low detection limit of 0.08 μg L-1. The CDs@ZIF-8@SMIP-based fluorescence strategy achieved satisfactory recoveries (95.5 % - 101.0 %) in CAP-spiked commercial foods with RSD < 4.4 % (n = 3). These results indicate that this method can effectively detect trace CAP in food matrices and has broad application prospects.

Recent advances and potential applications for metal-organic framework (MOFs) and MOFs-derived materials: Characterizations and antimicrobial activities

Microbial infections, particularly those caused by antibiotic-resistant pathogens, pose a critical global health threat. Metal-Organic Frameworks (MOFs), porous crystalline structures built from metal ions and organic linkers, initially developed for gas adsorption, have emerged as promising alternatives to traditional antibiotics. This review, covering research up to 2023, explores the potential of MOFs and MOF-based materials as broad-spectrum antimicrobial agents against bacteria, viruses, fungi, and even parasites. It delves into the historical context of antimicrobial agents, recent advancements in MOF research, and the diverse synthesis techniques employed for their production. Furthermore, the review comprehensively analyzes the mechanisms of action by which MOFs combat various microbial threats. By highlighting the vast potential of MOFs, their diverse synthesis methods, and their effectiveness against various pathogens, this study underscores their potential as a novel solution to the growing challenge of antibiotic resistance.

Metal-Organic Framework-Based Materials for Advanced Sodium Storage: Development and Anticipation

As a pioneering battery technology, even though sodium-ion batteries (SIBs) are safe, non-flammable, and capable of exhibiting better temperature endurance performance than lithium-ion batteries (LIBs), because of lower energy density and larger ionic size, they are not amicable for large-scale applications. Generally, the electrochemical storage performance of a secondary battery can be improved by monitoring the composition and morphology of electrode materials. Because more is the intricacy of a nanostructured composite electrode material, more electrochemical storage applications would be expected. Despite the conventional methods suitable for practical production, the synthesis of metal-organic frameworks (MOFs) would offer enormous opportunities for next-generation battery applications by delicately systematizing the structure and composition at the molecular level to store sodium ions with larger sizes compared with lithium ions. Here, the review comprehensively discusses the progress of nanostructured MOFs and their derivatives applied as negative and positive electrode materials for effective sodium storage in SIBs. The commercialization goal has prompted the development of MOFs and their derivatives as electrode materials, before which the synthesis and mechanism for MOF-based SIB electrodes with improved sodium storage performance are systematically discussed. Finally, the existing challenges, possible perspectives, and future opportunities will be anticipated.

In situ growth of Zr-based metal-organic frameworks on cellulose sponges for Hg2+ and methylene blue removal

Metal-organic frameworks (MOFs) are characterised by high porosity levels and controllable structures, making them ideal adsorbents for wastewater. However, obtaining substrate materials with mechanical stability, excellent pore accessibility, and good processability for compositing MOF crystal powders to adsorb multiple pollutants in complex aqueous environments is challenging. In this study, porous MOFs@ modified cellulose sponge (MCS) composites were fabricated using MCS as a scaffold to provide anchoring sites for the coordination of Zr4+ ions and further in situ synthesis of MOFs, namely UiO-66@MCS and UiO-66-NH2@MCS, which effectively removed heavy metal ions and organic dyes. MOFs@MCS composites exhibit excellent water and dimensional stability, maintaining the pore structure by ambient drying during reuse. Compared with UiO-66@MCS composite, UiO-66-NH2@MCS composite exhibited a higher adsorption capacity of 224.5 mg·g-1 for Hg2+ and 400.9 mg·g-1 for methylene blue (MB). The adsorption of Hg2+ onto the MOFs@MCS composites followed the Langmuir and pseudo-second-order models, whereas the Freundlich and pseudo-second-order models were more suitable for MB adsorption. Moreover, the MOFs@MCS composites exhibited excellent reusability and were selective for the removal of Hg2+. Overall, this approach effectively combines Zr-based MOFs with mechanically and dimensionally stable porous cellulose sponges, rendering the approach suitable for purifying complex wastewater.

Exquisitely constructing hierarchical carbon nanoarchitectures decorated with sulfides for high-performance Li-S batteries

The sluggish reaction kinetics and notorious shuttle effect of polysulfides significantly hinder the practical application of lithium-sulfur batteries (LSBs). Therefore, polysulfides are anchored and their conversion reactions are catalyzed to enhance the performance of LSBs. Herein, an exquisite hierarchical carbon nanoarchitecture decorated with sulfides is designed and introduced into LSBs. Systematic experiments show that the nanoarchitecture not only enables rapid electron/ion migration but also functions as an active catalyst to increase polysulfide conversion, thus effectively reducing the shuttle effect. As a result, LSBs with the nanoarchitecture modified separator exhibited outstanding rate capacity (724.9 mA h g-1 at 5C), low self-discharge capacity loss (4.1% capacity loss after 72 h), and exceptional reversible capacity (1518.3 mA h g-1 at 0.1C and 25.6% capacity loss after 100 cycles). Through the design of a multifunctional separator, this study offers an effective way to minimize the shuttle effect and speed up redox conversion. The strategy of constructing nanoarchitectures provides an innovative route for hierarchical heterocatalyst design for LSBs.

Recent Advances in Hierarchical Porous Engineering of MOFs and Their Derived Materials for Catalytic and Battery: Methods and Application

Hierarchical porous materials have attracted the attention of researchers due to their enormous specific surface area, maximized active site utilization efficiency, and unique structure and properties. In this context, metal-organic frameworks (MOFs) offer a unique mix of properties that make them particularly appealing as tunable porous substrates containing highly active sites. This review focuses on recent advances in the types and synthetic strategies of hierarchical porous MOFs and their derived materials. Furthermore, it highlights the relationship between the mass diffusion and transport of hierarchical porous structures and the pore size with examples and simulations, while identifying their potential and limitations. On this basis, how the synthesis conditions affect the structure and electrochemical properties of MOFs based hierarchical porous materials with different structures is discussed, highlighting the prospects and challenges for the synthetization, as well as further scientific research and practical applications. Finally, some insights into current research and future design ideas for advanced MOFs based hierarchical porous materials are presented.

Preparation and extraction property study of corn cob-like magnetic mosaic carbon materials derived from MOF-on-MOF composites

BACKGROUND

Large accumulations of pesticide residues in the environment eventually enter the human body with food. Based on magnetic solid-phase extraction (MSPE) technology, it is possible to achieve efficient extraction of trace pesticide residues in foodstuffs, and the construction of MSPE adsorbents with excellent magnetic properties and many active sites is still one of the main research topics. Based on this, we developed a new strategy for the preparation of "MOF-on-MOF" composites, which were carbonized and used as adsorbents for the extraction of pesticide residues in cereals.

RESULTS

A novel corn cob core-shell composite Fe2O3@C@ZIF-8 was created by embedding ZIF-8 onto the surface of Fe2O3@C derived from MIL-88A(Fe), and used for the extraction of benzoylurea insecticides(BUs) from cereals. The adsorption behaviour between Fe2O3@C@ZIF-8 and BUs was investigated by static and kinetic experiments and the adsorption mechanism was elaborated. For the trace analysis of BUs, a magnetic solid-phase extraction combined with high performance liquid chromatography-ultraviolet detector (HPLC-UV) approach was also developed. Under the optimized experimental conditions, the limits of detection and quantification were 0.015-0.03 μg L-1 and 0.05-0.1 μg L-1, and the relative standard deviations for the intra-day and inter-day ranges were 1.82%-2.13 % and 3.85%-4.59 %, respectively. The spiked recoveries of the four cereals ranged from 82.72% to 104.45 %. After 10 cycles of use of Fe2O3@C@ZIF-8, the recoveries of BUs ranged from 77.90% to 96.74 %.

SIGNIFICANCE

The analytical method based on Fe2O3@C@ZIF-8 as adsorbent has a low limit of detection, a wide linear range and is highly applicable to the analysis of real samples. In addition, the strategy developed in this study for the preparation of thermoplastic polymer-assisted "MOF-on-MOF" composites has promising applications.

3D nitrogen-doped carbon frameworks with hierarchical pores and graphitic carbon channels for high-performance hybrid energy storages

In principle, hybrid energy storages can utilize the advantages of capacitor-type cathodes and battery-type anodes, but their cathode and anode materials still cannot realize a high energy density, fast rechargeable capability, and long-cycle stability. Herein, we report a strategy to synthesize cathode and anode materials as a solution to overcome this challenge. Firstly, 3D nitrogen-doped hierarchical porous graphitic carbon (NHPGC) frameworks were synthesized as cathode materials using Co-Zn mixed metal-organic frameworks (MOFs). A high capacity is achieved due to the abundant nitrogen and micropores produced by the MOF nanocages and evaporation of Zn. Also, fast ion/electron transport channels were derived through the Co-catalyzed hierarchical porosity control and graphitization. Moreover, tin oxide precursors were introduced in NHPGC to form the SnO2@NHPGC anode. Operando X-ray diffraction revealed that the rescaled subnanoparticles as anodic units facilitated the high capacity during ion insertion-induced rescaling. Besides, the Sn-N bonds endowed the anode with a cycling stability. Furthermore, the NHPGC cathode and SnO2@NHPGC achieved an ultrahigh energy density (up to 244.5 W h kg-1 for Li and 146.1 W h kg-1 for Na), fast rechargeable capability (up to 93C-rate for Li and 147C-rate for Na) as exhibited by photovoltaic recharge within a minute and a long-cycle stability with ∼100% coulombic efficiency over 10 000 cycles.

Nanoleaf-derived carbon materials as a sensitivity coating for solid‑phase microextraction of polycyclic aromatic hydrocarbons

Metal-organic framework-derived carbon materials have shown extensive application in the sensitive extraction of polycyclic aromatic hydrocarbons (PAHs), but more active sites for its adsorption were still a tireless pursuit. In this study, ZIF-nanoleaf-derived carbon (NLCs) was synthesized and developed as a solid-phase microextraction (SPME) fiber (NLCs-F). The extraction performance was compared with ZIF-dodecahedron-derived carbon (DHCs) coated fiber (DHCs-F), which was prepared by only changing the ratio of the reactants. The unique morphology of NLCs provided abundant adsorption active sites for the selected PAHs, while the large average aperture facilitated selective extraction of high molecular weight analytes. Additionally, the high carbon content enhanced the strong enrichment capability for hydrophobic PAHs. Hence, the prepared NLCs-F coupled with GC-MS showed a good correlation coefficient (0.9975) in a wide linear range, low limits of detection (0.3-1.8 ng L-1), satisfactory repeatability, and reproducibility, which made it apply in the enrichment of PAHs in actual tea and coffee samples.

Recent progress of MOF-functionalized nanocomposites: From structure to properties

Metal-organic frameworks (MOFs) are novel crystalline porous materials assembled from metal ions and organic ligands. The adaptability of their design and the fine-tuning of the pore structures make them stand out in porous materials. Furthermore, by integrating MOF guest functional materials with other hosts, the novel composites have synergistic benefits in numerous fields such as batteries, supercapacitors, catalysis, gas storage and separation, sensors, and drug delivery. This article starts by examining the structural relationship between the host and guest materials, providing a comprehensive overview of the research advancements in various types of MOF-functionalized composites reported to date. The review focuses specifically on four types of spatial structures, including MOFs being (1) embedded in nanopores, (2) immobilized on surface, (3) coated as shells and (4) assembled into hybrids. In addition, specific design ideas for these four MOF-based composites are presented. Some of them involve in situ synthesis method, solvothermal method, etc. The specific properties and applications of these materials are also mentioned. Finally, a brief summary of the advantages of these four types of MOF composites is given. Hopefully, this article will help researchers in the design of MOF composite structures.

Cation-doped sea-urchin-like MnO2 for electrocatalytic overall water splitting

It is necessary to take full account of the activity, selectivity, dynamic performance, economic benefits, and environmental impact of the catalysts in the overall water splitting of electrocatalysis for the reasonable design of electrocatalysts. Designing nanostructures of catalysts and optimizing defect engineering are considered environmentally friendly and cost-effective electrocatalyst synthesis strategies. Herein, we report that metal cations regulate the microstructure of sea-urchin-like MnO2 and act as dopants to cause the lattice expansion of MnO2, resulting in crystal surface defects. The valence unsaturated Mn4+/Mn3+ greatly promotes the electrocatalytic oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). The optimal Al-MnO2 showed that the overpotential is 390 and 170 mV in the process of catalyzing OER and HER, respectively, at a current density of 10 mA cm-2. It is exciting to note that after 5000 cycles of Al-MnO2 within the kinetic potential range of OER and HER, its performance remained almost unchanged. This work provides a simple, efficient, and environmentally friendly route for the design of efficient integrated water-splitting electrocatalysts.

Carbon Nitrides from Supramolecular Crystals: From Single Atoms to Heterojunctions and Advanced Photoelectrodes

Carbon nitride materials (CN) have become one of the most studied photocatalysts within the last 15 years. While CN absorbs visible light, its low porosity and fast electron-hole recombination hinder its photoelectric performance and have motivated the research in the modification of its physical and chemical properties (such as energy band structure, porosity, or chemical composition) by different means. In this Concept we review the utilization of supramolecular crystals as CN precursors to tailor its properties. We elaborate on the features needed in a supramolecular crystal to serve as CN precursor, we delve on the influence of metal-free crystals in the morphology and porosity of the resulting materials and then discuss the formation of single atoms and heterojunctions when employing a metal-organic crystal. We finally discuss the performance of CN photoanodes derived from crystals and highlight the current standing challenges in the field.

Carbon-Based Nanomaterials Electrodes of Ionic Soft Actuators: From Initial 1D Structure to 3D Composite Structure for Flexible Intelligent Devices

With the rapid development of autonomous and intelligent devices driven by soft actuators, ion soft actuators in flexible intelligent devices have several advantages over other actuators, including their light weight, low voltage drive, large strain, good flexibility, fast response, etc. Traditional ionic polymer metal composites have received a lot of attention over the past decades, but they suffer from poor driving performance and short service lives since the precious metal electrodes are not only expensive, heavy, and labor-intensive, but also prone to cracking with repeated actuation. As excellent candidates for the electrode materials of ionic soft actuators, carbon-based nanomaterials have received a lot of interest because of their plentiful reserves, low cost, and excellent mechanical, electrical, and electrochemical properties. This research reviewed carbon-based nanomaterial electrodes of ion soft actuators for flexible smart devices from a fresh perspective from 1D to 3D combinations. The design of the electrode structure is introduced after the driving mechanism of ionic soft actuators. The details of ionic soft actuator electrodes made of carbon-based nanomaterials are then provided. Additionally, a summary of applications for flexible intelligent devices is provided. Finally, suggestions for challenges and prospects are made to offer direction and inspiration for further development.

Metal-organic framework derived inverse opal type 3D graphitic carbon for highly stable lithium-ion batteries

Graphitic carbon-based anodes for lithium-ion batteries have seen remarkable development and commercial acceptance during the past three decades. Still, the performance of these materials is limited due to the low surface area, stacking of layers, poor porosity, and meager conductivity. To overcome these limitations, we propose using polystyrene as a core and small-sized zeolitic imidazolate framework-67 (ZIF-67) particles as decorators to develop a highly porous three-dimensional graphitic carbon material. The developed material is optimized with the carbonization temperature for the best anodic performance of LIBs. The pyridinic nitrogen content in the material carbonized at 700 °C makes it high performing and more stable than the samples treated at 600, 800, and 900 °C. The packed coin cell exhibited an initial discharge capacity of 775 mA h g-1 at a current density of 50 mA g-1, which increases to 806 mA h g-1 after testing the material at different current densities for 55 cycles. The packed half-cell exhibited a highly stable performance of about 96% even after testing for 2000 cycles at 1 A g-1.

Versatile Synthesis of Carbon Materials using Protic Ionic Liquids and Salts as Precursors

Carbon materials (CMs) hold immense potential for applications across a wide range of fields. However, current precursors often confront limitations such as low heteroatom content, poor solubility, or complicated preparation and post-treatment procedures. Our research has unveiled that protic ionic liquids and salts (PILs/PSs), generated from the neutralization of organic bases with protonic acids, can function as economical and versatile small-molecule carbon precursors. The resultant CMs display attractive features, including elevated carbon yield, heightened nitrogen content, improved graphitic structure, robust thermal stability against oxidation, and superior conductivity, even surpassing that of graphite. These properties can be elaborate modulated by varying the molecular structure of PILs/PSs. In this Personal Account, we summarize recent developments in PILs/PSs-derived CMs, with a particular focus on the correlations between precursor structure and the physicochemical properties of CMs. We aim to impart insights into the foreseeable controlled synthesis of advanced CMs.

Amino-Functionalized Hierarchical Porous Carbon Derived from Zeolitic Imidazolate Frameworks for Ultrasensitive Electrochemical Sensing of Heavy Metals in Water

Electrochemical sensing provides a feasible avenue to monitor heavy metal ions (HMIs) in water, whereas the construction of highly sensitive and selective sensors remains challenging. Herein, we fabricated a novel amino-functionalized hierarchical porous carbon by the template-engaged method using ZIF-8 as the precursor and polystyrene sphere as the template, followed by carbonization and controllable chemical grafting of amino groups for efficient electrochemical detection of HMIs in water. The amino-functionalized hierarchical porous carbon features an ultrathin carbon framework with a high graphitization degree, excellent conductivity, unique macro-, meso-, and microporous architecture, and rich amino groups. As a result, the sensor exhibits prominent electrochemical performance with significantly low limits of detection for individual HMIs (i.e., 0.93 nM for Pb²⁺, 2.9 nM for Cu²⁺, and 1.2 nM for Hg²⁺) and simultaneous detection of HMIs (i.e., 0.62 nM for Pb²⁺, 1.8 nM for Cu²⁺, and 0.85 nM for Hg²⁺), which are superior to most reported sensors in the literature. Moreover, the sensor displays excellent anti-interference ability, repeatability, and stability for HMI detection in actual water samples.

Metal organic framework-derived recyclable magnetic coral Co@Co3O4/C for adsorptive removal of antibiotics from wastewater

The menace posed by antibiotic contamination to humanity has increased due to the absence of efficient antibiotic removal processes in the conventional waste water treatment methods from the hospitals, households, animal husbandry, and pharma industry. Importantly, only a few commercially available adsorbents are magnetic, porous, and have the ability to selectively bind and separate various classes of antibiotics from the slurries. Herein, we report the synthesis of a coral-like Co@Co3O4/C nanohybrid for the remediation of three different classes of antibiotics - quinolone, tetracycline, and sulphonamide. The coral like Co@Co3O4/C materials are synthesized via a facile room temperature wet chemical method followed by annealing in a controlled atmosphere. The materials demonstrate an attractive porous structure with an excellent surface-to-mass ratio of 554.8 m2 g-1 alongside superior magnetic responses. A time-varying adsorption study of aqueous nalidixic acid solution on Co@Co3O4/C nanohybrids indicates that these coral-like Co@Co3O4/C nanohybrids could achieve a high removal efficiency of 99.98% at pH 6 in 120 min. The adsorption kinetics data of Co@Co3O4/C nanohybrids follow a pseudo-second-order reaction kinetics suggesting a chemisorption effect. The adsorbent has also shown its merit in reusability for four adsorption-desorption cycles without showing significant change in the removal efficiency. More in-depth studies validate that the excellent adsorption capability of Co@Co3O4/C adsorbent attributing to the electrostatic and π-π interaction between adsorbent and various antibiotics. Concisely, the adsorbent manifests the potential for the removal of a wide range of antibiotics from the water alongside showing their utility in the hassle-free magnetic separation.

Phase Change Thermal Storage Materials for Interdisciplinary Applications

Functional phase change materials (PCMs) capable of reversibly storing and releasing tremendous thermal energy during the isothermal phase change process have recently received tremendous attention in interdisciplinary applications. The smart integration of PCMs with functional supporting materials enables multiple cutting-edge interdisciplinary applications, including optical, electrical, magnetic, acoustic, medical, mechanical, and catalytic disciplines etc. Herein, we systematically discuss thermal storage mechanism, thermal transfer mechanism, and energy conversion mechanism, and summarize the state-of-the-art advances in interdisciplinary applications of PCMs. In particular, the applications of PCMs in acoustic, mechanical, and catalytic disciplines are still in their infancy. Simultaneously, in-depth insights into the correlations between microscopic structures and thermophysical properties of composite PCMs are revealed. Finally, current challenges and future prospects are also highlighted according to the up-to-date interdisciplinary applications of PCMs. This review aims to arouse broad research interest in the interdisciplinary community and provide constructive references for exploring next generation advanced multifunctional PCMs for interdisciplinary applications, thereby facilitating their major breakthroughs in both fundamental researches and commercial applications.

Facet Engineering of Advanced Electrocatalysts Toward Hydrogen/Oxygen Evolution Reactions

The crystal facets featured with facet-dependent physical and chemical properties can exhibit varied electrocatalytic activity toward hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) attributed to their anisotropy. The highly active exposed crystal facets enable increased mass activity of active sites, lower reaction energy barriers, and enhanced catalytic reaction rates for HER and OER. The formation mechanism and control strategy of the crystal facet, significant contributions as well as challenges and perspectives of facet-engineered catalysts for HER and OER are provided.

The electrocatalytic water splitting technology can generate high-purity hydrogen without emitting carbon dioxide, which is in favor of relieving environmental pollution and energy crisis and achieving carbon neutrality. Electrocatalysts can effectively reduce the reaction energy barrier and increase the reaction efficiency. Facet engineering is considered as a promising strategy in controlling the ratio of desired crystal planes on the surface. Owing to the anisotropy, crystal planes with different orientations usually feature facet-dependent physical and chemical properties, leading to differences in the adsorption energies of oxygen or hydrogen intermediates, and thus exhibit varied electrocatalytic activity toward hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). In this review, a brief introduction of the basic concepts, fundamental understanding of the reaction mechanisms as well as key evaluating parameters for both HER and OER are provided. The formation mechanisms of the crystal facets are comprehensively overviewed aiming to give scientific theory guides to realize dominant crystal planes. Subsequently, three strategies of selective capping agent, selective etching agent, and coordination modulation to tune crystal planes are comprehensively summarized. Then, we present an overview of significant contributions of facet-engineered catalysts toward HER, OER, and overall water splitting. In particular, we highlight that density functional theory calculations play an indispensable role in unveiling the structure–activity correlation between the crystal plane and catalytic activity. Finally, the remaining challenges in facet-engineered catalysts for HER and OER are provided and future prospects for designing advanced facet-engineered electrocatalysts are discussed.

Fabrication of PA-PEI-MOF303(Al) by Stepwise Impregnation Layer-by-Layer Growth for Highly Efficient Removal of Ammonia

NH₃ is a typical alkaline gaseous pollutant widely derived from industrial production and poses great risks to humans and other biota. Metal-organic frameworks (MOFs) have excellent adsorption capacities relative to materials traditionally used to adsorb NH₃. However, in practice, applications of MOFs as adsorbents are restricted because of its powder form. We prepared a polyamide (PA) macroporous polyester substrate using an emulsion template method and modified the surface with polyethylenimine (PEI) to improve the MOF growth efficiency on the substrate. The difficulty of loading the MOF because of the fast nucleation rate inside the PA macroporous polyester substrate was solved using a stepwise impregnation layer-by-layer (LBL) growth method, and a PA-PEI-MOF303(Al) hierarchical pore composite that very efficiently adsorbed NH₃ was successfully prepared. The PA-PEI-MOF303(Al) adsorption capacity for NH₃ was 16.07 mmol·g^-1 at 298 K and 100 kPa, and the PA-PEI-MOF303(Al) could be regenerated repeatedly under vacuum at 423 K. The NH₃ adsorption mechanism was investigated by in situ Fourier transform infrared spectroscopy and by performing two-dimensional correlation analysis. Unlike for the MOF303(Al) powder, the formation of multi-site hydrogen bonds between Al-O-Al/C-OH, N-H, -OH, C=O, and NH₃ in PA-PEI-MOF303(Al) was found to be an important reason for efficient NH₃ adsorption. This study will provide a reference for the preparation of other MOF-polymer composites.

Graphene-Based Metal-Organic Framework Hybrids for Applications in Catalysis, Environmental, and Energy Technologies

Current energy and environmental challenges demand the development and design of multifunctional porous materials with tunable properties for catalysis, water purification, and energy conversion and storage. Because of their amenability to de novo reticular chemistry, metal-organic frameworks (MOFs) have become key materials in this area. However, their usefulness is often limited by low chemical stability, conductivity and inappropriate pore sizes. Conductive two-dimensional (2D) materials with robust structural skeletons and/or functionalized surfaces can form stabilizing interactions with MOF components, enabling the fabrication of MOF nanocomposites with tunable pore characteristics. Graphene and its functional derivatives are the largest class of 2D materials and possess remarkable compositional versatility, structural diversity, and controllable surface chemistry. Here, we critically review current knowledge concerning the growth, structure, and properties of graphene derivatives, MOFs, and their graphene@MOF composites as well as the associated structure-property-performance relationships. Synthetic strategies for preparing graphene@MOF composites and tuning their properties are also comprehensively reviewed together with their applications in gas storage/separation, water purification, catalysis (organo-, electro-, and photocatalysis), and electrochemical energy storage and conversion. Current challenges in the development of graphene@MOF hybrids and their practical applications are addressed, revealing areas for future investigation. We hope that this review will inspire further exploration of new graphene@MOF hybrids for energy, electronic, biomedical, and photocatalysis applications as well as studies on previously unreported properties of known hybrids to reveal potential "diamonds in the rough".

Metal-Organic Frameworks and Their Composites for Environmental Applications

From the point of view of the ecological environment, contaminants such as heavy metal ions or toxic gases have caused harmful impacts on the environment and human health, and overcoming these adverse effects remains a serious and important task. Very recent, highly crystalline porous metal-organic frameworks (MOFs), with tailorable chemistry and excellent chemical stability, have shown promising properties in the field of removing various hazardous pollutants. This review concentrates on the recent progress of MOFs and MOF-based materials and their exploit in environmental applications, mainly including water treatment and gas storage and separation. Finally, challenges and trends of MOFs and MOF-based materials for future developments are discussed and explored.

Cu-functionalised porous boron nitride derived from a metal-organic framework

Porous boron nitride (BN) displays promising properties for interfacial and bulk processes, e.g. molecular separation and storage, or (photo)catalysis. To maximise porous BN's potential in such applications, tuning and controlling its chemical and structural features is key. Functionalisation of porous BN with metal nanoparticle represents one possible route, albeit a hardly explored one. Metal-organic frameworks (MOFs) have been widely used as precursors to synthesise metal functionalised porous carbon-based materials, yet MOF-derived metal functionalised inorganic porous materials remain unexplored. Here, we hypothesise that MOFs could also serve as a platform to produce metal-functionalised porous BN. We have used a Cu-containing MOF, i.e. Cu/ZIF-8, as a precursor and successfully obtained porous BN functionalised with Cu nanoparticles (i.e. Cu/BN). While we have shown control of the Cu content, we have not yet demonstrated it for the nanoparticle size. The functionalisation has led to improved light harvesting and enhanced electron-hole separation, which have had a direct positive impact on the CO2 photoreduction activity (production formation rate 1.5 times higher than pristine BN and 12.5 times higher than g-C3N4). In addition, we have found that the metal in the MOF precursor impacts porous BN's purity. Unlike Cu/ZIF-8, a Co-containing ZIF-8 precursor led to porous C-BN (i.e. BN with a large amount of C in the structure). Overall, given the diversity of metals in MOFs, one could envision our approach as a method to produce a library of different metal functionalised porous BN samples.

Photocatalytic Reduction of Hexavalent Chromium Using Cu3.21Bi4.79S9/g-C3N4 Nanocomposite

The photocatalytic reduction of hexavalent chromium, Cr(VI), to the trivalent species, Cr(III), has continued to inspire the synthesis of novel photocatalysts that are capable of achieving the task of converting Cr(VI) to the less toxic and more useful species. In this study, a novel functionalized graphitic carbon nitride (Cu3.21Bi4.79S9/gC3N4) was synthesized and characterized by using X-ray diffraction (XRD), thermogravimetry analysis (TGA), energy-dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), transmission electron microscope (TEM), and scanning electron microscope (SEM). The composite was used for the photocatalytic reduction of hexavalent chromium, Cr(VI), under visible light irradiation. A 92.77% efficiency of the reduction was achieved at pH 2, using about 10 mg of the photocatalyst and 10 mg/L of the Cr(VI) solution. A pseudo-first-order kinetic study indicated 0.0076 min−1, 0.0286 min−1, and 0.0393 min−1 rate constants for the nanoparticles, pristine gC3N4, and the nanocomposite, respectively. This indicated an enhancement in the rate of reduction by the functionalized gC3N4 by 1.37- and 5.17-fold compared to the pristine gC3N4 and Cu3.21Bi4.79S9, respectively. A study of how the presence of other contaminants including dye (bisphenol A) and heavy-metal ions (Ag(I) and Pb(II)) in the system affects the photocatalytic process showed a reduction in the rate from 0.0393 min−1 to 0.0019 min−1 and 0.0039 min−1, respectively. Finally, the radical scavenging experiments showed that the main active species for the photocatalytic reduction of Cr(VI) are electrons (e−), hydroxyl radicals (·OH−), and superoxide (·O2−). This study shows the potential of functionalized gC3N4 as sustainable materials in the removal of hexavalent Cr from an aqueous solution.

Zeolite Imidazolate Frameworks (ZIFs) Derived Nanomaterials and their Hybrids for Advanced Secondary Batteries and Electrocatalysis

Zeolite imidazolate frameworks (ZIFs), as a typical class of metal-organic frameworks (MOFs), have attracted a great deal of attention in the field of energy storage and conversation due to their chemical structure stability, facile synthesis and environmental friendliness. Among of ZIFs family, the zinc-based imidazolate framework (ZIF-8) and cobalt-based imidazolate framework (ZIF-67) have considered as promising ZIFs materials, which attributed to their tunable porosity, stable structure, and desirable electrical conductivity. To date, various ZIF-8 and ZIF67 derived materials, including carbon materials, metal oxides, sulfides, selenides, carbides and phosphides, have been successfully synthesized using ZIFs as templates and evaluated as promising electrode materials for secondary batteries and electrocatalysis. This review provides an effective guide for the comprehension of the performance optimization and application prospects of ZIFs derivatives, specifically focusing on the optimization of structure and their application in secondary batteries and electrocatalysis. In detail, we present recent advances in the improvement of electrochemical performance of ZIF-8, ZIF-67 and ZIF-8@ZIF-67 derived nanomaterials and their hybrids, including carbon materials, metal oxides, carbides, oxides, sulfides, selenides, and phosphides for high-performance secondary batteries and electrocatalysis.

Metal-Thiolate Framework for Electrochemical and Photoelectrochemical Hydrogen Generation

Hydrogen has evolved as the cleanest and most sustainable fuel, produced directly from naturally abundant water resources. Generation of hydrogen by electrochemical or photoelectrochemical splitting of water has been conceived as the most effective method for hydrogen production. Herein, a robust solid metal-thiolate framework (MTF-1) was obtained by hydrothermal crystallization of the reaction mixture consisting of 1,3,5-triazine-2,4,6-trithioltrisodium salt and Cu^II under mild synthesis conditions. The material was thoroughly characterized and explored as efficient catalyst for electrochemical and photoelectrochemical hydrogen evolution reaction (HER) via water splitting reactions. MTF-1 showed onset potential 0.045 V_RHE and overpotential η(@10 mA cm^-2 ) at 0.096 V_RHE . The electrochemical surface area of MTF-1 was found to be 509 m²  g^-1 . The photo current density at pH 5.0 was found to be 0.487 mA cm^-2 at 0.6 V_RHE . The feasibility of the reaction pathway was correlated from the density function theory study, which suggested the complete downhill energetics indicating spontaneous electrochemical hydrogen generation in the acidic medium.

Modulating the Electronic Structure of FeCo Nanoparticles in N-Doped Mesoporous Carbon for Efficient Oxygen Reduction Reaction

The development of highly efficient and stable oxygen reduction electrocatalysts and revealing their underlying catalytic mechanism are crucial in expanding the applications of metal-air batteries. Herein, an excellent FeCo alloy nanoparticles (NPs)-decorated N-doped mesoporous carbon electrocatalyst (FeCo/NC) for oxygen reduction reaction, prepared through the pyrolysis of a dual metal containing metal-organic framework composite scaffold is reported. Benefiting from the highly exposed bimetal active sites and the carefully designed structure, the Fe_0.25 Co_0.75 /NC-800 catalyst exhibits a promising electrocatalytic activity and a superior durability, better than those of the state-of-the-art catalysts. Suggested by both the X-ray absorption fine structures and the density functional theoretical calculation, the outstanding catalytic performance is originated from the synergistic effects of the bimetallic loading in NC catalysts, where the electronic modulation of the Co active sites from the nearby Fe species leads to an optimized binding strength for reaction intermediates. This work demonstrates a class of highly active nonprecious metals electrocatalysts and provides valuable insights into investigating the structure-performance relationship of transition metal-based alloy catalysts.

Introduction of a Zn-based metal-organic framework @ biomass porous activated carbon as a high-sensitive coating for a stainless steel SPME fiber: application to the simultaneous analysis of nonsteroidal anti-inflammatory drugs

The present study introduces a high-efficiency nanocomposite material featuring a zinc-based metal-organic framework and a novel porous activated carbon derived from bread waste. The prepared nanocomposite, namely Zn-MOF-5@BHPAC, has been synthesized by a low-temperature hydrothermal process and coated onto the surface of a stainless steel wire with epoxy glue. The fabricated fiber has been employed as an SPME fiber applied in the extraction and pre-concentration of some nonsteroidal anti-inflammatory drugs (NSAIDs) before their high-performance liquid chromatography-ultraviolet (HPLC-UV) studies. The characterization studies were performed utilizing field emission scanning electron microscopy, elemental mapping, energy-dispersive X-ray spectroscopy, elemental analyzer, Fourier-transform infrared spectroscopy, and Brunauer-Emmett-Teller surface area analysis. Under the optimal conditions, the method demonstrated low detection limits (LODs, 0.06-0.15 µg L-1), wide linear ranges (LRs, 0.20-380 µg L-1) with good linearity (R2 > 0.991), good precisions (RSDs < 6.95%), and acceptable relative recoveries (RR > 85%). Using the green and affordable biomass of bread as a novel carbon-rich source is an innovative idea provided in this study. In addition, the hybridization of the obtained carbon-based material with the MOF compound to create a new high-capacity sorbent is another strength of the proposed method. Long service lifetime, economic efficiency, environmental friendliness, and high extraction capability were some of the other advantages of the suggested procedure. Therefore, the method can utilize successfully for the simultaneous determination of NSAIDs (as model analytes) in different matrixes.

Solvent-Mediated Synthesis of Hierarchical MOFs and Derived Urchin-Like Pd@SC/HfO2 with High Catalytic Activity and Stability

Carbon materials with hierarchical morphologies, pores, and compositions have attracted extraordinary attention due to their unique structural advantages and widespread applications. However, their controllable synthesis remains a grand challenge. Herein, a solvent-mediated strategy was demonstrated for the preparation of an urchin-like superstructure via modulating the hydrothermal condition (acetic acid/water ratio) of metal-organic frameworks (MOFs). The direct pyrolysis of a hierarchical NUS-6 precursor produced a well-defined carbon-based composite consisting of sulfur-doped carbon (SC) and HfO₂ with an urchin-like morphology and micro-/mesoporosity, while the doped S sites and oxygen vacancies of HfO₂ can help to anchor and activate Pd nanoparticles (NPs) through the strong host-guest interaction, which was further confirmed by the calculated results of the binding energy and differential charge density through density functional theory (DFT). The synthesized Pd@SC/HfO₂ composite exhibited extremely high catalytic activity and stability toward the water-phase hydrodeoxygenation of vanillin (conversion >99%, selectivity >99%), as well as good universality for the hydrogenation of a series of unsaturated hydrocarbons in an aqueous system. Remarkably, the catalytic activity and structural stability of Pd@SC/HfO₂ were largely maintained even after successive 10 cycles.

Hybrid Organic–Inorganic Membranes for Photocatalytic Water Remediation

Mismanagement, pollution and excessive use have depleted the world’s water resources, producing a shortage that in some territories is extreme. In this context, the need for potable water prompts the development of new and more efficient wastewater treatment systems to overcome shortages by recovering and reusing contaminated water. Among the water treatment methods, membrane technology is considered one of the most promising. Besides, photocatalytic degradation has become an attractive and efficient technology for water and wastewater treatment. However, the use of unsupported catalysts has as its main impediment their separation from the water once treated. With this, providing the membranes with this photocatalyzed degradation capacity can improve the application of photocatalysts, since in many cases their application improves their recovery and reuse. This review describes the general photocatalytic processes of the main inorganic nanoparticles used as fillers in hybrid polymeric membranes. In addition, the most recent hybrid organic–inorganic membranes are reviewed. Finally, the membranes formed by metal–organic frameworks that can be considered one of the newest and most versatile developments are described.