•A deep analysis on low concentration CO2 removal using physical adsorbents is proposed.•In-depth understanding of what are the crucial criteria for materials to be used in CO2 capture.•MOFs have ...valuable assets vs. benchmark materials such as zeolites.•High porosity is not necessarily important for traces and low CO2 concentration capture.•The uniformity of energetic adsorption sites is not a critical parameter for traces CO2 capture.
The capture and separation of traces and concentrated CO2 from important commodities such as CH4, H2, O2 and N2, is becoming important in many areas related to energy security and environmental sustainability. While trace CO2 concentration removal applications have been modestly studied for decades, the spike in interest in the capture of concentrated CO2 was motivated by the need for new energy vectors to replace highly concentrated carbon fuels and the necessity to reduce emissions from fossil fuel-fired power plants. CO2 capture from various gas streams, at different concentrations, using physical adsorbents, such as activated carbon, zeolites, and metal–organic frameworks (MOFs), is attractive. However, the adsorbents must be designed with consideration of many parameters including CO2 affinity, kinetics, energetics, stability, capture mechanism, in addition to cost. Here, we perform a systematic analysis regarding the key technical parameters that are required for the best CO2 capture performance using physical adsorbents. We also experimentally demonstrate a suitable material model of metal organic framework as advanced adsorbents with unprecedented properties for CO2 capture in a wide range of CO2 concentration. These recently developed class of MOF adsorbents represent a breakthrough finding in the removal of traces CO2 using physical adsorption. This platform shows colossal tuning potential for more efficient separation agents and guide researchers on the crucial criteria to be considered in the development of adsorbents for traces and low concentration CO2 capture.
Direct air capture is regarded as a plausible alternate approach that, if economically practical, can mitigate the increasing carbon dioxide emissions associated with two of the main carbon polluting ...sources, namely stationary power plants and transportation. Here we show that metal-organic framework crystal chemistry permits the construction of an isostructural metal-organic framework (SIFSIX-3-Cu) based on pyrazine/copper(II) two-dimensional periodic 4(4) square grids pillared by silicon hexafluoride anions and thus allows further contraction of the pore system to 3.5 versus 3.84 Å for the parent zinc(II) derivative. This enhances the adsorption energetics and subsequently displays carbon dioxide uptake and selectivity at very low partial pressures relevant to air capture and trace carbon dioxide removal. The resultant SIFSIX-3-Cu exhibits uniformly distributed adsorption energetics and offers enhanced carbon dioxide physical adsorption properties, uptake and selectivity in highly diluted gas streams, a performance, to the best of our knowledge, unachievable with other classes of porous materials.
This review highlights various design and synthesis approaches toward the construction of ZMOFs, which are metal-organic frameworks (MOFs) with topologies and, in some cases, features akin to ...traditional inorganic zeolites. The interest in this unique subset of MOFs is correlated with their exceptional characteristics arising from the periodic pore systems and distinctive cage-like cavities, in conjunction with modular intra- and/or extra-framework components, which ultimately allow for tailoring of the pore size, pore shape, and/or properties towards specific applications.
Illustration of various strategies for the construction of zeolite-like metal-organic frameworks (ZMOFs) based on vertex decoration and/or edge-expansion.
For the first time, functionality has been covalently introduced into the Cr-MIL-101 network by post-synthetic modification of the terephthalate linker molecule through nitration. The nitro group was ...reduced and the amino group was reacted with ethyl isocyanate to yield the corresponding urea derivative.
In this review, we describe two recently implemented conceptual approaches facilitating the design and deliberate construction of metal-organic frameworks (MOFs), namely supermolecular building block ...(SBB) and supermolecular building layer (SBL) approaches. Our main objective is to offer an appropriate means to assist/aid chemists and material designers alike to rationally construct desired functional MOF materials, made-to-order MOFs. We introduce the concept of
net
-coded building units (
net
-cBUs), where precise embedded geometrical information codes uniquely and matchlessly a selected net, as a compelling route for the rational design of MOFs. This concept is based on employing pre-selected 0-periodic metal-organic polyhedra or 2-periodic metal-organic layers, SBBs or SBLs respectively, as a pathway to access the requisite
net
-cBUs. In this review, inspired by our success with the original
rht
-MOF, we extrapolated our strategy to other known MOFs
via
their deconstruction into more elaborate building units (namely polyhedra or layers) to (i) elucidate the unique relationship between edge-transitive polyhedra or layers and minimal edge-transitive 3-periodic nets, and (ii) illustrate the potential of the SBB and SBL approaches as a rational pathway for the design and construction of 3-periodic MOFs. Using this design strategy, we have also identified several new hypothetical MOFs which are synthetically targetable.
A toolbox for the design of made-to-order MOFs: Pinpointing the rationale and benefits of the Supermolecular Building Block (SBB) and Supermolecular Building Layer (SBL) approaches.
25 Years of Reticular Chemistry Freund, Ralph; Canossa, Stefano; Cohen, Seth M. ...
Angewandte Chemie International Edition,
November 2, 2021, Letnik:
60, Številka:
45
Journal Article
Recenzirano
Odprti dostop
At its core, reticular chemistry has translated the precision and expertise of organic and inorganic synthesis to the solid state. While initial excitement over metal–organic frameworks (MOFs) and ...covalent organic frameworks (COFs) was undoubtedly fueled by their unprecedented porosity and surface areas, the most profound scientific innovation of the field has been the elaboration of design strategies for the synthesis of extended crystalline solids through strong directional bonds. In this contribution we highlight the different classes of reticular materials that have been developed, how these frameworks can be functionalized, and how complexity can be introduced into their backbones. Finally, we show how the structural control over these materials is being extended from the molecular scale to their crystal morphology and shape on the nanoscale, all the way to their shaping on the bulk scale.
Reticular chemistry translates the precision and expertise of organic and inorganic synthesis to the solid state. The most profound innovation of the field has been the elaboration of design strategies for the synthesis of extended crystalline solids through strong directional bonds. This Review highlights the classes of reticular materials, their functionalization, and the introduction of complexity into their backbones.
Controlling the shape of metal–organic framework (MOF) crystals is important for understanding their crystallization and useful for myriad applications. However, despite the many advances in shaping ...of inorganic nanoparticles, post‐synthetic shape control of MOFs and, in general, molecular crystals remains embryonic. Herein, we report using a simple wet‐chemistry process at room temperature to control the anisotropic etching of colloidal ZIF‐8 and ZIF‐67 crystals. Our work enables uniform reshaping of these porous materials into unprecedented morphologies, including cubic and tetrahedral crystals, and even hollow boxes, by an acid–base reaction and subsequent sequestration of leached metal ions. Etching tests on these ZIFs reveal that etching occurs preferentially in the crystallographic directions richer in metal–ligand bonds; that, along these directions, the etching rate tends to be faster on the crystal surfaces of higher dimensionality; and that the etching can be modulated by adjusting the pH of the etchant solution.
Post‐synthetic wet‐chemical anisotropic etching of colloidal ZIF‐8 and ZIF‐67 crystals enables uniform reshaping of them into unprecedented shapes, including cubic and tetrahedral crystals, and even hollow boxes, by an acid–base reaction and subsequent sequestration of leached metal ions.
Metal-organic frameworks (MOFs) are a promising class of porous materials because it is possible to mutually control their porous structure, composition and functionality. However, it is still a ...challenge to predict the network topology of such framework materials prior to their synthesis. Here we use a new rare earth (RE) nonanuclear carboxylate-based cluster as an 18-connected molecular building block to form a gea-MOF (gea-MOF-1) based on a (3,18)-connected net. We then utilized this gea net as a blueprint to design and assemble another MOF (gea-MOF-2). In gea-MOF-2, the 18-connected RE clusters are replaced by metal-organic polyhedra, peripherally functionalized so as to have the same connectivity as the RE clusters. These metal-organic polyhedra act as supermolecular building blocks when they form gea-MOF-2. The discovery of a (3,18)-connected MOF followed by deliberate transposition of its topology to a predesigned second MOF with a different chemical system validates the prospective rational design of MOFs.
The exchange of the monocarboxylate ligand of the zirconium methacrylate oxocluster Zr(6)O(4)(OH)(4)(OMc)(12) (OMc = CH(2)=CH(CH(3))COO) with dicarboxylic acids (trans,trans muconic acid and ...terephthalic acid) leads to porous zirconium dicarboxylates exhibiting the UiO-66 architecture; the mild reaction conditions allow the control of their particle size.
A series of porous Zr oxoclusters-based MOFs was computationally explored for their gas storage/capture performances. The highly porous UiO-67(Zr) and UiO-68(Zr) solids show exceptionally high CH(4) ...and CO(2) adsorption capacities under operating conditions that make these thermal, water and mechanical resistant materials very promising for physisorption-based processes.
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