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the rational design of the basic building units, it is possible to incorporate MOF catalysts with high-density active sites and adjustable chemical/physical microenvironments, expanding MOFs' application prospects from the heterogeneous catalysis to more types of catalytic reactions, such as photocatalysis and electrocatalysis. [4] Over the past 20 years, over 88 000 structures have been recorded in Cambridge Structural Database (CSD), and the structural tunability allows us to tailormake MOF materials with different properties. [5] In the early stage, researchers mainly focused on pristine MOFs where active sites came from either the coordination unsaturated metal centers or organic ligands. [6] Additionally, considerable efforts have been made to regulate the porosity and pore shapes/sizes through optimizing the components and structures, which is conducive to not only the diffusion of molecules, but also the realization of size-selective catalysis. [7] Furthermore, some researchers added modifiers into the precursors which can control the sizes/morphologies and defects of MOF catalysts. Deliberately introducing defects into ordered frameworks is useful to expand the active sites species of MOF catalysts. [8] However, due to the limitation of the catalytic reaction types, the development of MOF catalysts has reached a bottleneck to some extent. Under this context, MOF composites emerged. The porous property of MOFs can be served as support to encapsulate different functional materials, such as metal nanoparticles (MNPs), organic molecules, biomolecules, and polymers into pores or cavities, which is an effective way to enrich active sites species and reaction types as well as to realize efficient catalysis. [4a,9] Further, the desire for energy related catalysis promoted the development of MOFbased catalysts. Specifically, the post-treatment methods for MOFs has rapidly advanced, which can modify the compositions, structures, and morphologies of as-synthesized MOFs. [10] This is best exemplified by the thermal treatment of MOFs to porous carbons, metal compounds, and single-atom catalysts (SACs), which show highly dispersed active centers, excellent stability, and adjustable components. [11] From a scientific point of view, MOF materials are interesting catalysts as their structural/component tunability allows us to tailor-make materials with various methods. However, it is quite complicated to construct specific MOF catalysts based on the numerous structures Metal-organic frameworks (MOFs) have emerged as one of the most widely investigated materials in catalysis mainly due to their excellent component tunability, high surface area, adjustable pore size, and uniform active sites. However, the overwhelming number of MOF materials and complex structures has brought difficulties for researchers to select and construct suitable MOF-based catalysts. Herein, a programmable design strategy is presented based on metal ions/clusters, organic ligands, modifiers, functional materials, and post-treatment modules, which c...

The electrochemical nitrogen reduction reaction (NRR), a contributor for producing ammonia under mild conditions sustainably, has recently attracted global research attention. Thus far, the design of highly efficient electrocatalysts to enhance NRR efficiency is a specific focus of the research. Among them, defect engineering of electrocatalysts is considered a significant way to improve electrocatalytic efficiency by regulating the electronic state and providing more active sites that can give electrocatalysts better physicochemical properties. Recently, metal–organic frameworks (MOFs), along with their derivatives, have captured immense interest in electrocatalytic reactions owing to not only their large surface area and high porosity but also the ability to create rich defects in their structures. Hence, they can provide plenty of exposed active sites for electron transfer, NN cleavage, and N2 adsorption to enhance NRR performance. Herein, the concept, the in situ characterizations techniques for defects, and the most common ways to create defects into MOFs have been summarized. Furthermore, the recent advances of MOF‐based electrocatalysts towards NRR have been recapitulated. Ultimately, the major challenges and outlook of defects in MOFs for NRR are proposed. This paper is anticipated to provide critical guidelines for optimizing NRR electrocatalysts.

Although there are plenty of merits for lithium–sulfur (Li–S) batteries, their undesired shuttle effect and insulated nature are hindering the practical applications. Here, a conductive metal–organic framework (MOF)-modified separator has been designed and fabricated through a facile filtration method to address the issues. Specifically, its intrinsic microporous structure, hydrophilic polar property, and conductive feature could make it easy to contact with and trap polysulfides and boost the kinetics of electrochemical reactions. Both the physical and chemical properties of the as-prepared separator are beneficial to alleviating the shuttle effect and enhancing the rate capability. Accordingly, the electrochemical performance of the battery with a MOF-modified separator was significantly improved.

The development of advanced anode materials is crucial to enhance the performance of sodium-ion batteries (SIBs). In this study, SnSe 2 nanoparticles chemically embedded in a carbon shell (SnSe 2 @C) were fabricated from Sn−organic frameworks and evaluated as an anode material for SIBs. The structural characterization demonstrated that there existed C−Sn chemical bonds between the SnSe 2 nanoparticles and carbon shell, which could strongly anchor SnSe 2 nanoparticles to the carbon shell. Such a structure can not only facilitate charge transfer but also ensure the structural stability of the SnSe 2 @C electrode. In addition, the carbon shell also helped in the dispersion of SnSe 2 nanoparticles, thus offering more redox-active sites for Na + storage. The as-prepared SnSe 2 @C nanocomposite could deliver good cycling stability and a superior rate capability of 324 mA h g −1 at 2 A g −1 for SIBs.