Metal-organic frameworks (MOFs), also known as porous coordination polymers (PCPs), synthesized by assembling metal ions with organic ligands have recently emerged as a new class of crystalline ...porous materials. The amenability to design as well as fine-tunable and uniform pore structures makes them promising materials for a variety of applications. Controllable integration of MOFs and functional materials is leading to the creation of new multifunctional composites/hybrids, which exhibit new properties that are superior to those of the individual components through the collective behavior of the functional units. This is a rapidly developing interdisciplinary research area. This review provides an overview of the significant advances in the development of diverse MOF composites reported till now with special emphases on the synergistic effects and applications of the composites. The most widely used and successful strategies for composite synthesis are also presented.
This review focuses on the recent progress in designing and fabricating metal-organic framework (MOF) composites for diverse functional applications.
The search for hydrogen storage materials capable of efficiently storing hydrogen in a compact and lightweight package is one of the most difficult challenges for the upcoming hydrogen economy. ...Liquid chemical hydrides with high gravimetric and volumetric hydrogen densities have the potential to overcome the challenges associated with hydrogen storage. Moreover, the liquid-phase nature of these hydrogen storage systems provides significant advantages of easy recharging, and the availability of the current liquid fuel infrastructure for recharging. In this review, we briefly survey the research progress in the development of diverse liquid-phase chemical hydrogen storage materials, including organic and inorganic chemical hydrides, with emphases on the syntheses of active catalysts for catalytic hydrogen generation and storage. Moreover, the advantages and drawbacks of each storage system are discussed.
In this review, we survey the research progress in catalytic hydrogen generation from, and the regeneration of, diverse liquid-phase chemical hydrogen storage materials, including both organic and inorganic chemical hydrides.
Herein, the authors report, for the first time, the semisacrificial template growth of a self‐supporting metal–organic framework (MOF) nanocomposite electrode composed of ultrasmall iron‐rich ...Fe(Ni)‐MOF cluster‐decorated ultrathin Ni‐rich Ni(Fe)‐MOF nanosheets from the NiFe alloy foam, in which the Fe(Ni)‐MOF clusters are uniform with a particle size of 2–5 nm, while the thickness of the Ni(Fe)‐MOF nanosheets is only about 1.56 nm. When directly used as a self‐supported working electrode for the oxygen evolution reaction (OER), it can afford an impressive electrocatalytic performance with required overpotentials of 227 and 253 mV to achieve current densities of 10 and 100 mA cm−2, respectively, much outperforming the benchmark of RuO2 and most state‐of‐the‐art noble‐metal‐free catalysts. Characterizations demonstrated that the combination of the unique nanostructure of the catalyst and the strong coupling effect between Ni and Fe active sites should be responsible for its excellent OER performance. Remarkably, when coupled with a Pt electrode in an overall water splitting system, they only needed 1.537 V to achieve a current density of 10 mA cm−2. The facile and economical methodology represents a new way to design and prepare high‐performance self‐supporting MOF electrocatalysts for highly efficient electrochemical processes.
A self‐supporting MOF nanocomposite electrode composed of ultrasmall iron‐rich Fe(Ni)‐MOF cluster‐decorated ultrathin Ni‐rich Ni(Fe)‐MOF nanosheets is prepared by a semisacrificial template growth method. The combination of the unique nanostructure and the strong coupling effect between Ni and Fe active sites endow the composite electrode with excellent electrocatalytic oxygen evolution reaction performance.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
The electrochemical hydrogen evolution reaction (HER) is an attractive technology for the mass production of hydrogen. Ru‐based materials are promising electrocatalysts owing to the similar bonding ...strength with hydrogen but much lower cost than Pt catalysts. Herein, an ordered macroporous superstructure of N‐doped nanoporous carbon anchored with the ultrafine Ru nanoclusters as electrocatalytic micro/nanoreactors is developed via the thermal pyrolysis of ordered macroporous single crystals of ZIF‐8 accommodating Ru(III) ions. Benefiting from the highly interconnected reticular macro–nanospaces, this superstrucure affords unparalleled performance for pH‐universal HER, with order of magnitude higher mass activity compared to the benchmark Pt/C. Notably, an exceptionally low overpotential of only 13 mV@10 mA cm−2 is required for HER in alkaline solution, with a low Tafel slope of 40.41 mV dec−1 and an ultrahigh turnover frequency value of 1.6 H2 s−1 at 25 mV, greatly outperforming Pt/C. Furthermore, the hydrogen generation rates are almost twice those of Pt/C during practical overall alkaline water splitting. A solar‐to‐hydrogen system is also demonstrated to further promote the application. This research may open a new avenue for the development of advanced electrocatalytic micro/nanoreactors with controlled morphology and excellent performance for future energy applications.
An ordered macroporous superstructure of nitrogen‐doped nanoporous carbon implanted with ultrafine Ru nanoclusters is developed via thermal pyrolysis of the ordered macroporous single crystals of ZIF‐8 accommodating Ru(III) ions, which affords unparalleled performance for the pH‐universal hydrogen evolution reaction, with order of magnitude higher mass activity compared to the benchmark Pt/C.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
AuNi alloy nanoparticles were successfully immobilized to MIL-101 with size and location control for the first time by double solvents method (DSM) combined with a liquid-phase ...concentration-controlled reduction strategy. When an overwhelming reduction approach was employed, the uniform 3D distribution of the ultrafine AuNi nanoparticles (NPs) encapsulated in the pores of MIL-101 was achieved, as demonstrated by TEM and electron tomographic measurements, which brings light to new opportunities in the fabrication of ultrafine non-noble metal-based NPs throughout the interior pores of MOFs. The ultrafine AuNi alloy NPs inside the mesoporous MIL-101 exerted exceedingly high activity for hydrogen generation from the catalytic hydrolysis of ammonia borane.
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IJS, KILJ, NUK, PNG, UL, UM
Recently, a new class of 2D materials, i.e., transition metal carbides, nitrides, and carbonitrides known as MXenes, is unveiled with more than 20 types reported one after another. Since they are ...flexible and conductive, MXenes are expected to compete with graphene and other 2D materials in many applications. Here, a general route is reported to simple self‐assembly of transition metal oxide (TMO) nanostructures, including TiO2 nanorods and SnO2 nanowires, on MXene (Ti3C2) nanosheets through van der Waals interactions. The MXene nanosheets, acting as the underlying substrate, not only enable reversible electron and ion transport at the interface but also prevent the TMO nanostructures from aggregation during lithiation/delithiation. The TMO nanostructures, in turn, serve as the spacer to prevent the MXene nanosheets from restacking, thus preserving the active areas from being lost. More importantly, they can contribute extraordinary electrochemical properties, offering short lithium diffusion pathways and additional active sites. The resulting TiO2/MXene and SnO2/MXene heterostructures exhibit superior high‐rate performance, making them promising high‐power and high‐energy anode materials for lithium‐ion batteries.
Transition metal oxide (TMO) nanostructures are self‐assembled on MXene nanosheets in tetrahydrofuran through van der Waals interactions, resulting in novel TMO/MXene heterostructures. Due to remarkable morphological and functional synergy, the TMO/MXene heterostructures exhibit superior high‐rate performance, which rank them as promising anode materials for fast and stable lithium storage.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
The thermal transformation of metal–organic frameworks (MOFs) generates a variety of nanostructured materials, including carbon-based materials, metal oxides, metal chalcogenides, metal phosphides ...and metal carbides. These derivatives of MOFs have characteristics such as high surface areas, permanent porosities and controllable functionalities that enable their good performance in sensing, gas storage, catalysis and energy-related applications. Although progress has been made to tune the morphologies of MOF-derived structures at the nanometre scale, it remains crucial to further our knowledge of the relationship between morphology and performance. In this Review, we summarize the synthetic strategies and optimized methods that enable control over the size, morphology, composition and structure of the derived nanomaterials. In addition, we compare the performance of materials prepared by the MOF-templated strategy and other synthetic methods. Our aim is to reveal the relationship between the morphology and the physico-chemical properties of MOF-derived nanostructures to optimize their performance for applications such as sensing, catalysis, and energy storage and conversion.Nanomaterials derived from metal–organic frameworks (MOFs) show good performance in sensing, gas storage, catalysis and energy-related applications. In this Review, the influence of the morphology of MOF-derived nanostructures on their performance is elucidated, and the opportunities in this field are discussed.
Electrochemical reduction of CO2 to valuable fuels is appealing for CO2 fixation and energy storage. However, the development of electrocatalysts with high activity and selectivity in a wide ...potential window is challenging. Herein, atomically thin bismuthene (Bi‐ene) is pioneeringly obtained by an in situ electrochemical transformation from ultrathin bismuth‐based metal–organic layers. The few‐layer Bi‐ene, which possesses a great mass of exposed active sites with high intrinsic activity, has a high selectivity (ca. 100 %), large partial current density, and quite good stability in a potential window exceeding 0.35 V toward formate production. It even deliver current densities that exceed 300.0 mA cm−2 without compromising selectivity in a flow‐cell reactor. Using in situ ATR‐IR spectra and DFT analysis, a reaction mechanism involving HCO3− for formate generation was unveiled, which brings new fundamental understanding of CO2 reduction.
Atomically thin bismuthene with excellent electrocatalytic CO2 reduction performance is obtained from ultrathin metal–organic layers by an in situ electrochemical transformation process. A reaction route involving HCO3− for formate production is revealed.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
•Characteristics of MOF-based materials for catalytic CO2 reduction are summarized.•The origins of the active sites in MOF-based materials are summarized.•Recent progress in the MOF-based CO2 ...reduction has been reviewed.•Challenges and perspectives of MOF-based materials for CO2 reduction are discussed.
Metal–organic frameworks (MOFs) have attracted much attention in photo- and electrocatalytic CO2 reduction into value-added chemicals. In this review, we specially focus on the active sites of MOF-based materials to achieve visible-light absorption and efficient charge separation for photocatalytic CO2 reduction, and conductivity for electrocatalytic CO2 reduction, respectively. Firstly, the unique characteristics of MOF-based materials for catalytic CO2 reduction are introduced. Subsequently, an overview on the recent progress and development of MOF-based materials for catalytic CO2 reduction are summarized by categorizing the types of the MOF-based materials and the origin of the active sites. The active metal nodes/clusters and organic ligands can be assembled in pristine MOFs for catalytic CO2 reduction. Diverse active species are also popular to integrate with MOFs to form MOF composites for catalytic CO2 reduction. Besides, MOFs and their composites are intensively explored as templates and/or precursors to synthesize MOF derivatives for catalytic CO2 reduction. Finally, the challenges and perspectives for further development towards MOF-based materials for CO2 reduction are proposed. We have tried our best to summarize the MOF-based materials for photo- and electrocatalytic CO2 reduction, aiming to inspire further ideas and exploration in this research field.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The unique features of the metal–organic frameworks (MOFs), including ultrahigh porosities and surface areas, tunable pores, endow the MOFs with special utilizations as host matrices. In this work, ...various neutral and ionic guest dye molecules, such as fluorescent brighteners, coumarin derivatives, 4‐(dicyanomethylene)‐2‐methyl‐6‐(p‐dimethylaminostyryl)‐4H‐pyran (DCM), and 4‐(p‐dimethylaminostyryl)‐1‐methylpyridinium (DSM), are encapsulated in a neutral MOF, yielding novel blue‐, green‐, and red‐phosphors, respectively. Furthermore, this study introduces the red‐, green‐, and blue‐emitting dyes into a MOF together for the first time, producing white‐light materials with nearly ideal Commission International ed'Eclairage (CIE) coordinates, high color‐rendering index values (up to 92%) and quantum yields (up to 26%), and moderate correlated color temperature values. The white light is tunable by changing the content or type of the three dye guests, or the excitation wavelength. Significantly, the introduction of blue‐emitting guests in the methodology makes the available MOF host more extensive, and the final white‐light output more tunable and high‐quality. Such strategy can be widely adopted to design and prepare white‐light‐emitting materials.
Three red‐green‐blue fluorescent dyes are encapsulated simultaneously into a metal–organic framework (MOF) for the first time, producing a series of efficient white‐light‐emitting composites. Significantly, the introduction of the blue‐emitting guest makes the final white light more tunable and higher quality, which can also broaden the available MOF matrices. This strategy will be widely adopted to design and prepare single‐phase white‐light materials.
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