Metal–organic structures have great potential for practical applications in many areas. However, their widespread use is often hindered by time-consuming and expensive synthesis procedures that often ...involve hazardous solvents and, therefore, generate wastes that need to be remediated and/or recycled. The development of cleaner, safer, and more sustainable synthesis methods is extremely important and is needed in the context of green chemistry. In this work, a facile mechanochemical method involving water-assisted ball milling was used for the synthesis of MOF-303. The obtained MOF-303 exhibited a high specific surface area of 1180 m2/g and showed an excellent CO2 adsorption capacity of 9.5 mmol/g at 0 °C and under 1 bar.
In this feature article we focus on the main developments in the area of ordered mesoporous materials (OMMs) since their discovery in 1992, which is considered one of the milestones in the history of ...porous materials. Nowadays, there are almost unlimited opportunities in the synthesis of composite- or modified OMMs by using soft- and hard-templating strategies and related methods. Nevertheless, there is still a great challenge to obtain diverse OMMs with well-developed porosity and desired morphology, crystallinity and surface properties. The evolution of the leading OMM members: silicas, organosilicas, metal oxides, carbons, metal-organic frameworks and zeolites, including the main factors affecting their development, is briefly summarized with special emphasis on the authors' accomplishments in this area. Additionally, recent advancements, challenges and prospects in the field of OMMs are presented.
This feature article presents the main developments in the area of ordered mesoporous materials (OMMs) since their discovery in 1992, which is considered one of the milestones in the history of porous materials.
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Metal–organic frameworks (MOFs) have attracted a special attention due to outstanding porosity, adjustable pore sizes, and huge opportunities in varying organic–inorganic ...compositions. Enormous studies conducted so far on MOFs indicate their high potential in catalysis, gas adsorption, drug delivery, water treatment, energy storage, among others. However, mass production of MOFs is still limited mainly due to the non-economic, non-green and complex synthesis methods. Mechanochemistry is an alternative solution for efficient and environmentally friendly syntheses of various MOFs. Fast and solvent-free or solvent-less mechanosynthesis seems to be a very powerful versatile method for obtaining these advanced porous materials. The mechanochemical concept was used for the preparation of various MOFs including the most popular structures: MOF-5, ZIF-8, HKUST-1, MIL-101, UiO-66. These MOFs feature high specific surface areas, comparable to those prepared by conventional solvent-based methods. Furthermore, mechanochemistry was successfully used for the synthesis of non-conventional multimetallic MOFs and previously unreported solid phases. This review shows the recent developments, challenges and perspectives of green synthesis of diverse MOF structures using mechanochemistry. Besides describing the mechanochemical synthesis of MOFs, some achievements in green applications are also summarized. Importantly, current trends in research suggests for further development of these fields i.e., harmful gas adsorption, water treatment, and energy storage.
Clean energy sources and global warming are among the major challenges of the 21st century. One of the possible actions toward finding alternative energy sources and reducing global warming are ...storage of H2 and CH4, and capture of CO2 by using highly efficient and low-cost adsorbents. Graphene and graphene-based materials attracted a great attention around the world because of their potential for a variety applications ranging from electronics, gas sensing, energy storage and CO2 capture. Large specific surface area of these materials up to ~3000m2/g and versatile modification make them excellent adsorbents for diverse applications. Here, graphene-based adsorbents are reviewed with special emphasis on their adsorption affinity toward CO2, H2 and CH4. This review shows that graphene derivatives obtained mainly via “chemical exfoliation” of graphite and further modification with polymers and/or metal species can be very effective sorbents for CO2 and other gases and can compete with the currently used carbonaceous or non-carbonaceous adsorbents. The high adsorption capacities of graphene-based materials are mainly determined by their unique nanostructures, high specific surface areas and tailorable surface properties, which make them suitable for storage or capture of various molecules relevant for environmental and energy-related applications.
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•Tuning adsorption properties of graphene by coupling with nanoparticles•Appraisal of properties of graphene materials for CO2, H2 and CH4 adsorption•Comparison of gas adsorption affinity for graphene, activated carbons and MOFs
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Nowadays, hybrid porous materials consisting of metal-organic frameworks (MOFs) and graphene nanosheets become more and more attractive because of their growing applications in ...adsorption, catalysis and related areas. Incorporation of graphene oxide into MOFs can provide benefits such as increased water resistance and thermal stability as well as enhanced surface area and adsorption properties. Graphene oxide is one of the best additives to other materials owing to its two main virtues: high atomic density and large amount of surface functional groups. Due to its dense array of atoms, graphene oxide can significantly increase dispersion forces in graphene-MOF materials, which is beneficial for adsorption of small molecules.
This work presents a concise appraisal of adsorption properties of MOFs and graphene-MOF hybrids toward CO2, volatile organic compounds, hydrogen and methane. It shows that the graphene-MOF materials represent an important class of materials with potential applications in adsorption and catalysis. A special emphasis of this article is placed on their adsorption applications for gas capture and storage. A large number of graphene-MOF adsorbents has been so far explored and their appraisal could be beneficial for researchers interested in the development of hybrid adsorbents for adsorption-based applications.
Activated carbons obtained from polymers, Cu-containing metal-organic framework (MOF) and their composites with graphene oxide were synthesized using facile methods and tested for the selective ...adsorption of CO2 over N2 at ambient conditions. The prepared materials have been characterized by scanning electron microscopy, X-ray diffraction analysis and N2 adsorption. The Cu-containing metal-organic framework showed high CO2 uptakes up to 9.59 mmol g−1 and 5.33 mmol g−1 under 1 bar at 0 °C and 25 °C, respectively. The MOF composite with ~10 wt % of graphene oxide exhibited the best CO2 adsorption selectivity over N2 among all samples studied. Although, most graphene-containing composites feature lower CO2 adsorption capacities, they show an enhanced CO2/N2 selectivity in comparison to the bare samples. This paper contains a comparative study of the CO2/N2 selectivity calculated by using different methods. Additionally, CH4 adsorption, CO2/CH4 selectivity and isosteric heat of CO2 adsorption were evaluated for the selected sorbents. This study indicates that graphene-containing composites are potential materials for large-scale selective CO2 capture at ambient conditions.
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•Enhancement of CO2/N2 selectivity of activated carbons and MOFs by adding GO.•A comparison of the CO2/N2 selectivity calculated by different methods.•CO2 adsorption and CO2/CH4 selectivity for GO-containing composites.
Conventional synthesis methods of functional materials are usually time- and energy consuming and contribute to the accumulation of waste solvents. An alternative solution is the use of ...environmentally friendly recipes such as mechanochemical synthesis, which may be employed for large-scale production of materials. Mechanochemistry has been applied in various areas, such as metallurgy, mineral processing, construction and synthesis of organic compounds, and currently it is experiencing a renaissance because of its successful implementation for the synthesis of diverse organic, inorganic and organic-inorganic hybrid nanomaterials. Here mechanochemical synthesis of highly porous materials is reviewed with special emphasis on novel sorbents. Mechanochemically-assisted methods are well suited for the preparation of highly porous carbons (such as lignin- or tannin-derived carbons), metal-organic frameworks (
e.g.
, MOF-5, MIL-101 and U-67) or covalent organic frameworks with specific surface areas up to 3500 m
2
g
−1
. Recently, ball milling was also utilized for the synthesis of ordered coordination polymers and perfectly ordered mesoporous carbons. Nowadays, mechanochemistry has become a powerful and quite universal method for the preparation of various materials. Hence, there is a need for a review summarizing the current accomplishments in this field. Most of the mechanochemically obtained porous materials reported so far have been designed for adsorption, catalysis and energy storage related applications.
Mechanochemistry became a powerful and popular method for the preparation of various porous materials.
Usually, porous materials are synthesized by using conventional electric heating, which can be energy‐ and time‐consuming. Microwave heating is commonly used in many households to quickly heat food. ...Microwave ovens can also be used as powerful devices in the synthesis of various porous materials. The microwave‐assisted synthesis offers a simple, fast, efficient, and economic way to obtain many of the advanced nanomaterials. This review summarizes the recent achievements in the microwave‐assisted synthesis of diverse groups of nanoporous materials including silicas, carbons, metal–organic frameworks, and metal oxides. Microwave‐assisted methods afford highly porous materials with high specific surface areas (SSAs), e.g., activated carbons with SSA ≈3100 m2 g−1, metal–organic frameworks with SSA ≈4200 m2 g−1, covalent organic frameworks with SSA ≈2900 m2 g−1, and metal oxides with relatively small SSA ≈300 m2 g−1. These methods are also successfully implemented for the preparation of ordered mesoporous silicas and carbons as well as spherically shaped nanomaterials. Most of the nanoporous materials obtained under microwave irradiation show potential applications in gas adsorption, water treatment, catalysis, energy storage, and drug delivery, among others.
Microwave ovens can be used as powerful devices in the synthesis of various porous materials including silicas, carbons, metal–organic frameworks, and metal oxides. Microwave‐assisted synthesis offers a simple, fast, efficient, and economic way to obtain nanoporous materials. The recent achievements in the microwave‐assisted synthesis of these diverse nanoporous materials and their potential applications are summarized.
Ultrasounds are commonly used in medical imaging, solution homogenization, navigation, and ranging, but they are also a great energy source for chemical reactions. Sonochemistry uses ultrasounds and ...thus realizes one of the basic concepts of green chemistry, i.e., energy savings. Moreover, reduced reaction time, mostly using water as a solvent, and better product yields are among the many factors that make ultrasound-induced reactions greener than those performed under conventional conditions. Sonochemistry has been successfully implemented for the preparation of various materials; this review covers sonochemically synthesized nanoporous materials. For instance, sonochemical-assisted methods afforded ordered mesoporous silicas, spherical mesoporous silicas, periodic mesoporous organosilicas, various metal oxides, biomass-derived activated carbons, carbon nanotubes, diverse metal-organic frameworks, and covalent organic frameworks. Among these materials, highly porous samples have also been prepared, such as garlic peel-derived activated carbon with an apparent specific surface area of 3887 m
/g and MOF-177 with an SSA of 4898 m
/g. Additionally, many of them have been examined for practical usage in gas adsorption, water treatment, catalysis, and energy storage-related applications, yielding satisfactory results.
Highly porous composites were synthesized via facile crystallization of a metal-organic framework (MOF) in mesopores of a three-dimensional (3D) graphene (MG). First, MG was prepared via facile ...thermal exfoliation of graphite oxide in air, which enabled sufficient separation of graphene sheets in the form of an interconnected 3D structure. Next, aluminum-based MOF MOF520: Al8(OH)8(BTB)4(HCOO)4, BTB = 4,4′,4”-benzene-1,3,5-tryil-tribenzoate was predominantly crystallized in mesopores of 3D structure having a large pore volume. The resulting MG-MOF composites possessed specific surface areas and pore volumes between those of MG (640 m2/g and 3.0 cm3/g) and MOF (3160 m2/g and 1.3 cm3/g). The composite consisting of MG and MOF with a weight ratio of 1:2 showed almost twice-larger benzene adsorption capacity, i.e., 24.5 mmol/g at 20 °C and relative pressure close to unity, in comparison to that of pure MOF. Although at the same conditions the pure MG captured an ultrahigh amount of benzene, i.e., 33.6 mmol/g, adsorption of this adsorbate at low and moderate relative pressures was much lower than that on pure MOF. Thus, the MG-MOF composites featured much better benzene adsorption performance in a wide range of relative pressures as compared to pure MG and MOF, respectively. Additionally, the composites featured better thermal stability in comparison to the pristine MOF. The use of MG in this synthesis method afforded the well-dispersed, small crystals of MOF, which is essential for the design of MOF-based composites.
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•Crystallization of MOF in mesopores of a three-dimensional graphene.•Enhancement of C6H6 adsorption by adding mesoporous graphene to MOF.•Ultrahigh C6H6 adsorption of 24.5 mmol/g on graphene-MOF composite at 20 °C.
