Metal-organic Framework-based Materials Research Articles

Metal-organic framework-based materials for solar-driven interfacial evaporation

As a sustainable and green approach, solar-driven interfacial water evaporation (SIE) can recover clean water from diverse water resources such as seawater and wastewater by converting solar energy into heat energy, paving the way to addressing the increasingly severe water shortage. In recent years, metal–organic frameworks (MOFs) have been applied for constructing the evaporator for SIE, considering their merits such as large specific surface area, tunable component and structure, and high porosity. More importantly, MOFs materials have expanded their application in the synthesis of porous carbon, metal oxides/sulfides/carbides, and MOFs composites, which not only may preserve the merits of MOFs but also possess other functions. In this review, the latest developments regarding the solar evaporators designed by MOFs-based materials (including MOFs, MOFs-derivatives, and MOFs composites) is summarized and systematically discussed. The roles of MOFs-based materials in evaporation systems and the emerging applications of the evaporation systems are also highlighted. Ultimately, the challenges and perspectives of the MOFs-based materials used for designing of SIE systems are also presented.

Hierarchically Ordered Pore Engineering of Carbon Supports with High-Density Edge-Type Single-Atom Sites to Boost Electrochemical CO2 Reduction.

Metal sites at the edge of the carbon matrix possess unique geometric and electronic structures, exhibiting higher intrinsic activity than in-plane sites. However, creating single-atom catalysts with high-density edge sites remains challenging. Herein, the hierarchically ordered pore engineering of metal-organic framework-based materials to construct high-density edge-type single-atomic Ni sites for electrochemical CO2 reduction reaction (CO2RR) is reported. The created ordered macroporous structure can expose enriched edges, further increased by hollowing the pore walls, which overcomes the low edge percentage in the traditional microporous substrates. The prepared single-atomic Ni sites on the ordered macroporous carbon with ultra-thin hollow walls (Ni/H-OMC) exhibit Faraday efficiencies of CO above 90% in an ultra-wide potential window of 600mV and a turnover frequency of 3.4×104h-1, much superior than that of the microporous material with dominant plane-type sites. Theory calculations reveal that NiN4 sites at the edges have a significantly disrupted charge distribution, forming electron-rich Ni centers with enhanced adsorption ability with *COOH, thereby boosting CO2RR efficiency. Furthermore, a Zn-CO2 battery using the Ni/H-OMC cathode shows an unprecedentedly high power density of 15.9mW cm-2 and maintains an exceptionally stable charge-discharge performance over 100h.

Separable Metal-Organic Framework-Based Materials for the Adsorption of Emerging Contaminants.

Thousands of chemicals have been released into the environment in recent decades. The presence of emerging contaminants (ECs) in water has emerged as a pressing concern. Adsorption is a viable solution for the removal of ECs. Metal-organic frameworks (MOFs) have shown great potential as efficient adsorbents, but their dispersed powder form limits their practical applications. Recently, researchers have developed various separable MOF-based adsorbents to improve their recyclability. The purpose of this review is to summarize the latest developments in the construction of separable MOF-based adsorbents and their applications in adsorbing ECs. The construction strategies for separable MOFs are classified into four categories: magnetic MOFs, MOF-fiber composites, MOF gels, and binder-assisted shaping. Typical emerging contaminants include pesticides, pharmaceuticals and personal care products, and endocrine-disrupting compounds. The adsorption performance of different materials is evaluated based on the results of static and dynamic adsorption experiments. Additionally, the regeneration methods of MOF-based adsorbents are discussed in detail to facilitate effective recycling and reuse. Finally, challenges and potential future research opportunities are proposed, including reducing performance losses during the shaping process, developing assessment systems based on dynamic purification and real polluted water, optimizing regeneration methods, designing multifunctional MOFs, and low-cost, large-scale synthesis of MOFs.

Synergistic Effect of In2O3/NC-Co3O4 Interface on Enhancing the Redox Conversion of Polysulfides for High-Performance Li-S Cathode Materials at Low Temperatures.

Lithium-sulfur (Li-S) batteries are considered as a promising energy storage technology due to their high energy density; however, the shuttling effect and sluggish redox kinetics of lithium polysulfides (LiPSs) severely deteriorate the electrochemical performance of Li-S batteries. Herein, we report a novel configuration wherein In2O3 and Co3O4 are incorporated into N-doped porous carbon as a sulfur host material (In2O3@NC-Co3O4) using metal-organic framework-based materials to synergistically tune the catalytic abilities of different metal oxides for different reaction stages of LiPSs, achieving a rapid redox conversion of LiPSs. In particular, the introduction of N-doped carbon improved the electron transport of the materials. The polar interface of In2O3 and Co3O4 anchors both long- and short-chain LiPSs and catalyzes long-chain and short-chain LiPSs, respectively, even at low temperatures. Consequently, the Li-S battery with In2O3@NC-Co3O4 cathode materials delivered an excellent discharge capacity of 1042.4 mAh g-1 at 1 C and a high capacity retention of 85.1% after 500 cycles. Impressively, the In2O3@NC-Co3O4 cathode displays superior performances at high current density and low temperature due to the enhanced redox kinetics, delivering 756 mAh g-1 at 2 C (room temperature) and 755 mAh g-1 at 0.1 C (-20 °C).

Hierarchically Ordered Pore Engineering of Metal-Organic Framework-Based Materials for Electrocatalysis.

Ordered pore engineering that embeds uniform pores with periodic alignment in electrocatalysts opens up a new avenue for achieving further performance promotion. Hierarchically ordered porous metal-organic frameworks (HOP-MOFs) possessing multilevel pores with ordered distribution are the promising precursors for the exploration of ordered porous electrocatalysts, while the scalable acquisition of HOP-MOFs with editable components and adjustable pore size regimes is critical. This review presents recent progress on hierarchically ordered pore engineering of MOF-based materials for enhanced electrocatalysis. The synthetic strategies of HOP-MOFs with different pore size regimes, including the self-assembly guided by reticular chemistry, surfactant, nanoemulsion, and nanocasting, are first introduced. Then the applications of HOP-MOFs as the precursors for exploring hierarchically ordered porous electrocatalysts are summarized, selecting representatives to highlight the boosted performance. Especially, the intensification of molecule and ion transport integrated with optimized electron transfer and site exposure over the hierarchically ordered porous derivatives are emphasized to clarify the directional transfer and integration effect endowed by ordered pore engineering. Finally, the remaining scientific challenges and an outlook of this field are proposed. It is hoped that this review will guide the hierarchically ordered pore engineering of nanocatalysts for boosting the catalytic performance and promoting the practical applications.

Metal organic framework-based materials for metal-ion batteries

The next-generation energy storage systems based on metal-ion batteries are essential for implementing renewable energy sources and the high-quality development of electric vehicles. Efficient metal-ion batteries require both high energy density and high power density. However, there are challenges in the current battery systems due to poor reaction kinetics, making them difficult to fully meet these requirements. Metal-organic frameworks (MOFs), with their high porosity, multifunctionality, structural diversity, and controllable chemical composition, can serve as catalysts in electrode materials, regulate interface interactions, and improve electrochemical redox kinetics, providing new ideas and possibilities for energy storage materials. Despite these advantages, MOF-based materials are still at their early stages for their applications in the field of electrochemical energy storage and face many challenges. This article reviews the research and development of MOF-based materials in various metal-ion batteries, especially for cathodes, anodes, separators, and electrolytes due to their distinctive structure and properties. It also discusses the mechanisms for improving the electrochemical performance of metal-ion batteries. Finally, the main challenges and prospects for MOF-based materials in metal-ion batteries are provided.

Trends in the energy and environmental applications of metal–organic framework-based materials

Over the past 20 years, metal–organic framework (MOF) nanosheets have garnered a great deal of interest in the fields of energy and environmental management because of their inherent extraordinary qualities.

Molecular Engineering of a Metal-Organic Polymer for Enhanced Electrochemical Nitrate-to-Ammonia Conversion and Zinc Nitrate Batteries.

Metal-organic framework-based materials are promising single-site catalysts for electrocatalytic nitrate (NO3 - ) reduction to value-added ammonia (NH3 ) on account of well-defined structures and functional tunability but still lack a molecular-level understanding for designing the high-efficient catalysts. Here, we proposed a molecular engineering strategy to enhance electrochemical NO3 - -to-NH3 conversion by introducing the carbonyl groups into 1,2,4,5-tetraaminobenzene (BTA) based metal-organic polymer to precisely modulate the electronic state of metal centers. Due to the electron-withdrawing properties of the carbonyl group, metal centers can be converted to an electron-deficient state, fascinating the NO3 - adsorption and promoting continuous hydrogenation reactions to produce NH3 . Compared to CuBTA with a low NO3 - -to-NH3 conversion efficiency of 85.1 %, quinone group functionalization endows the resulting copper tetraminobenzoquinone (CuTABQ) distinguished performance with a much higher NH3 FE of 97.7 %. This molecular engineering strategy is also universal, as verified by the improved NO3 - -to-NH3 conversion performance on different metal centers, including Co and Ni. Furthermore, the assembled rechargeable Zn-NO3 - battery based on CuTABQ cathode can deliver a high power density of 12.3 mW cm-2 . This work provides advanced insights into the rational design of metal complex catalysts through the molecular-level regulation for NO3 - electroreduction to value-added NH3 .

Metal–organic framework-based materials for photocatalytic overall water splitting: Status and prospects

Metal–organic framework-based materials for photocatalytic overall water splitting: Status and prospects

Adsorption performance study of bismuth-doped ZIF-8 composites on radioactive iodine in the vapor and liquid phases

Radioactive iodine generated from nuclear waste and nuclear accidents can cause serious hazards to the environment and human body. In this study, bismuth-doped ZIF-8 composites (Bi2O3@ZIF-8) were synthesized by in situ synthesis at room temperature to study their adsorption of iodine in gaseous state and in solution. The Bi2O3@ZIF-8 composites were characterized and analyzed by means of tests. Bi2O3@ZIF-8 exhibited high specific surface area and contained abundant microporous structures. However, when the bismuth doping amount reached 10%, 10%-Bi2O3@ZIF-8 appeared mesoporous. The specific surface area of 1%-Bi2O3@ZIF-8, 5%-Bi2O3@ZIF-8 and 10%-Bi2O3@ZIF-8 could reach 1110.6 m2/g, 973.21 m2/g and 927.82 m2/g, respectively. The adsorption of gaseous iodine by 5%-Bi2O3@ZIF-8 reached equilibrium after 3.5 h with the maximum adsorption capacity of 298 wt%. And the maximum adsorption capacity of iodine in solution was 751.4 mg/g. The effects of the initial concentration of the solution, reaction temperature and contact time on the adsorption process were investigated. The adsorption of Bi2O3@ZIF-8 on iodine was consistent with the pseudo-second-order kinetics and the Langmuir model. The results of thermodynamic studies indicated that the adsorption of iodine by Bi2O3@ZIF-8 was spontaneous and exothermic. This study provides a reference for the synthesis of metal organic framework-based materials and provides theoretical guidance for the removal of practical radioactive iodine.

Metal-Organic Framework-Based Materials for Wastewater Treatment: Superior Adsorbent Materials for the Removal of Hazardous Pollutants.

In previous years, different pollutants, for example, organic dyes, antibiotics, heavy metals, pharmaceuticals, and agricultural pollutants, have been of note to the water enterprise due to their insufficient reduction during standard water and wastewater processing methods. MOFs have been found to have potential toward wastewater management. This Review focused on the synthesis process (such as traditional, electrochemical, microwave, sonochemical, mechanochemical, and continuous-flow spray-drying method) of MOF materials. Moreover, the properties of the MOF materials have been discussed in detail. Further, MOF materials' applications for wastewater treatment (such as the removal of antibiotics, organic dyes, heavy metal ions, and agricultural waste) have been discussed. Additionally, we have compared the performances of some typical MOFs-based materials with those of other commonly used materials. Finally, the study's current challenges, future prospects, and outlook have been highlighted.

Metal–organic framework-based materials: emerging high-efficiency catalysts for the heterogeneous photocatalytic degradation of pollutants in water

Water pollution has become one of the most important global environmental pollution problems, wherein various toxic and persistent organic pollutants in water pose a major threat to the environment.

Soft Spray: An Emerging Technique for Metal-Organic Framework-Based Materials.

As an emerging type of microporous inorganic-organic hybrid material, metal-organic frameworks (MOFs) have become more and more universal in various application fields. Preparing high-performance MOF materials by a simple method has always been the pursuit of synthetic chemists and materials scientists. Recently, a new technique of so-called "soft spray", where the atomized droplets of one reactant solution are sprayed onto the surface of the other reactant solution at a slow speed, has been developed to fabricate MOF-based materials, such as nanoparticles, thin films, and hybrids. This Perspective aims at summarizing the latest research progress of the preparation of MOF-based materials by the soft spray technique, discussing the possible mechanism, highlighting its powerful controllability in the morphological structure, and exhibiting great promise as a simple, efficient, and scalable technique.

Achievements and Perspectives in Metal–Organic Framework-Based Materials for Photocatalytic Nitrogen Reduction

Metal–organic frameworks (MOFs) are coordination polymers with high porosity that are constructed from molecular engineering. Constructing MOFs as photocatalysts for the reduction of nitrogen to ammonia is a newly emerging but fast-growing field, owing to MOFs’ large pore volumes, adjustable pore sizes, controllable structures, wide light harvesting ranges, and high densities of exposed catalytic sites. They are also growing in popularity because of the pristine MOFs that can easily be transformed into advanced composites and derivatives, with enhanced catalytic performance. In this review, we firstly summarized and compared the ammonia detection methods and the synthetic methods of MOF-based materials. Then we highlighted the recent achievements in state-of-the-art MOF-based materials for photocatalytic nitrogen fixation. Finally, the summary and perspectives of MOF-based materials for photocatalytic nitrogen fixation were presented. This review aims to provide up-to-date developments in MOF-based materials for nitrogen fixation that are beneficial to researchers who are interested or involved in this field.

Metal-organic framework-based materials for the abatement of air pollution and decontamination of wastewater.

Developing new and efficient technologies for environmental remediation is becoming significant due to the increase in global concerns such as climate change, severe epidemics, and energy crises. Air pollution, primarily due to increased levels of H2S, SOx, NH3, NOx, CO, volatile organic compounds (VOC), and particulate matter (PM) in the atmosphere, has a significant impact on public health, and exhaust gases harm the natural sulfur, nitrogen, and carbon cycles. Similarly, wastewater discharged to the environment with metal ions, herbicides, pharmaceuticals, personal care products, dyes, and aromatics/organic compounds is a risk for health since it may lead to an outbreak of waterborne pathogens and increase the exposure to endocrine-disrupting agents. Therefore, developing new and efficient air and water quality management systems is critical. Metal-organic frameworks (MOFs) are novel materials for which the main application areas include gas storage and separation, water harvesting from the atmosphere, chemical sensing, power storage, drug delivery, and food preservation. Due to their versatile structural motifs that can be modified during synthesis, MOFs also have a great promise for green applications including air and water pollution remediation. The motivation to use MOFs for environmental applications prompted the modification of their structures via the addition of metal and functional groups, as well as the creation of heterostructures by mixing MOFs with other nanomaterials, to effectively remove hazardous contaminants from wastewater and the atmosphere. In this review, we focus on the state-of-the-art environmental applications of MOFs, particularly for water treatment and air pollution, by highlighting the groundbreaking studies in which MOFs have been used as adsorbents, membranes, and photocatalysts for the abatement of air and water pollution. We finally address the opportunities and challenges for the environmental applications of MOFs.

Recent advances in metal–organic framework-based materials for removal of fluoride in water: Performance, mechanism, and potential practical application

Clean water is necessary in all areas of life, especially for our body. Fluoride in water has serious negative effects on human health and the environment. Effectively repairing fluoride-polluted water remains a critical mission. Among the numerous technologies for removing fluoride from water, metal–organic framework (MOF) materials are regarded as promising adsorption materials. In this study, the synthesis of MOFs and their application progress in aquatic defluoridation in recent years, which are classified according to the central metal ions, are reviewed. In particular, an understanding of the effect factors for water remediation is provided, and the potential environmental application is analyzed. The adsorption mechanism and the evaluation on potential practical applications for fluoride removal by different MOFs are elucidated. Finally, future research opportunities and prospects of MOF-based materials for fluoride removal are proposed.

Recent advances in metal-organic framework-based materials for anti-staphylococcus aureus infection.

The rapid spread of staphylococcus aureus (S. aureus) causes an increased morbidity and mortality, as well as great economic losses in the world. Anti-S. aureus infection becomes a major challenge for clinicians and nursing professionals to address drug resistance. Hence, it is urgent to explore high efficiency, low toxicity, and environmental-friendly methods against S. aureus. Metal-organic frameworks (MOFs) represent great potential in treating S. aureus infection due to the unique features of MOFs including tunable chemical constitute, open crystalline structure, and high specific surface area. Especially, these properties endow MOF-based materials outstanding antibacterial effect, which can be mainly attributed to the continuously released active components and the exerted catalytic activity to fight bacterial infection. Herein, the structural characteristics of MOFs and evaluation method of antimicrobial activity are briefly summarized. Then we systematically give an overview on their recent progress on antibacterial mechanisms, metal ion sustained-release system, controlled delivery system, catalytic system, and energy conversion system based on MOF materials. Finally, suggestions and direction for future research to develop and mechanism understand MOF-based materials are discussed in antibacterial application.

Metal-Organic Framework-Based Materials for Adsorption and Detection of Uranium(VI) from Aqueous Solution.

The steady supply of uranium resources and the reduction or elimination of the ecological and human health hazards of wastewater containing uranium make the recovery and detection of uranium in water greatly important. Thus, the development of effective adsorbents and sensors has received growing attention. Metal–organic frameworks (MOFs) possessing fascinating characteristics such as high surface area, high porosity, adjustable pore size, and luminescence have been widely used for either uranium adsorption or sensing. Now pertinent research has transited slowly into simultaneous uranium adsorption and detection. In this review, the progress on the research of MOF-based materials used for both adsorption and detection of uranium in water is first summarized. The adsorption mechanisms between uranium species in aqueous solution and MOF-based materials are elaborated by macroscopic batch experiments combined with microscopic spectral technology. Moreover, the application of MOF-based materials as uranium sensors is focused on their typical structures, sensing mechanisms, and the representative examples. Furthermore, the bifunctional MOF-based materials used for simultaneous detection and adsorption of U(VI) from aqueous solution are introduced. Finally, we also discuss the challenges and perspectives of MOF-based materials for uranium adsorption and detection to provide a useful inspiration and significant reference for further developing better adsorbents and sensors for uranium containment and detection.

Use of Modularity as a Principle of Design of Metal-organic Framework-based Materials with Specified Properties for Creating Modern Protective Equipment

An earlier analysis of approaches to the creation and improvement of protective materials and tissues made it possible to assume that the development of personal protective equipment (PPE) against various damaging factors of chemical, biological and physical nature can in future go towards the creation of modular organometallic frame structures (MOF-materials) with specific properties (from toxic chemicals and pathogenic microorganisms). The aim of this article is to develop and disclose the principle of modularity of construction of protective materials based on MOF-structures with specific properties. The principle of modularity of construction of protective materials with specific properties, proposed by us, is based on the use of single unified platform, on the surface of which special modules or combinations of modules are applied, which ensure the protection from various factors of chemical, biological and physical nature. The universal structure of MOF, called «MOF-universal», has been substantiated. The composition and properties of individual modules, possible and optimal combinations of modules of MOF-structures, the importance and significance of individual modules and their combinations for imparting universal protective properties to MOF-material are determined. The use of this principle will make it possible to impart protective properties to almost any clothing, while maintaining its physiological and hygienic characteristics and providing the required level of protection for personnel, without using specialized personal protective equipment.

Contribution of hydrogen bonding to liquid-phase adsorptive removal of hazardous organics with metal-organic framework-based materials

Removing hazardous organics from water or fuel is important for our clean environment; adsorption over porous materials has been a competitive means to eliminate such organics. Here, the adsorption or removal of hazardous organics with metal–organic framework-based adsorbents was explained, especially adsorption that relies on hydrogen bonding (H-bonding). The bonding details (direction, quantitative contribution, importance of 6-membered rings, and characterizations to support H-bonding) and improved performance via H-bonding were investigated. Finally, prospects for further development or research in the relevant fields were suggested.