Flexibility in Metal–Organic Frameworks: A fundamental understanding

Elsaidi, Sameh K.; Mohamed, Mona H.; Banerjee, Debasis; Thallapally, Praveen K.

doi:10.1016/j.ccr.2017.11.022

Cited by 191 publications

(113 citation statements)

References 190 publications

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“…Metal–organic frameworks (MOFs) are one of the most highly porous materials and since their discovery, have been thoroughly investigated as a result of their specific properties that are exceptional among known materials . They combine two disciplines, namely organic and inorganic chemistry and possess many favorable characteristics, for example high surface area, high porosity, tenability, reproducibility, high sorption capacities, facile syntheses, and good possibilities for scale up .…”

Section: Introductionmentioning

confidence: 99%

Evaluation of the BET Theory for the Characterization of Meso and Microporous MOFs

et al. 2018

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Surface area determination with the Brunauer–Emmett–Teller (BET) method is a widely used characterization technique for metal–organic frameworks (MOFs). Since these materials are highly porous, the use of the BET theory can be problematic. Several researchers have evaluated the BET method to gain insights into the usefulness of the obtained results and interestingly, their findings are not always consistent. In this review, the suitability of the BET method is discussed for MOFs that have a diverse range of pore widths below the diameters of N2 or Ar and above 20 Å. In addition, the surface area of MOFs that are obtained by implementing different approaches, such as grand canonical Monte Carlo simulations, calculations from the crystal structures or based on experimental N2, Ar, or CO2 adsorption isotherms, are compared and evaluated. Inconsistencies in the state‐of‐the‐art are also noted. Based on the current literature, an overview is provided of how the BET method can give useful estimations of the surface areas for the majority of MOFs, but there are some crucial and specific exceptions which are highlighted in this review.

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Section: Introductionmentioning

confidence: 99%

Evaluation of the BET Theory for the Characterization of Meso and Microporous MOFs

et al. 2018

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“…As novel organic–inorganic hybrid crystalline porous materials, metal–organic frameworks (MOFs) are composed of metal ions or metal clusters bridged by multifarious organic ligands. The outstanding features of MOFs are that, through the wide design latitude of frameworks, they can offer unique structural diversity, porosity, and functionality . Based on the above advantages, MOFs have been explored for a wide variety of popular applications such as gas sorption and separation, catalysis, drug delivery, etc .…”

Section: Introductionmentioning

confidence: 99%

A Highly Stable Two‐Dimensional Copper(II) Organic Framework for Proton Conduction and Ammonia Impedance Sensing

Sun

Zhao

et al. 2018

Chemistry A European J

104

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This work reports the design and fabrication of a proton conductive 2D metal-organic framework (MOF), [Cu(p-IPhHIDC)] (1) (p-IPhH IDC=2-(p-N-imidazol-1-yl)-phenyl-1 H-imidazole-4,5-dicarboxylic acid) as an advanced ammonia impedance sensor at room temperature and 68-98 % relative humidity (RH). MOF 1 shows the optimized proton conductivity value of 1.51×10 S cm at 100 °C and 98 % RH. Its temperature-dependent and humidity-dependent proton conduction properties have been explored. The large amount of uncoordinated carboxylate groups between the layers plays a vital role in the resultant conductivity. Distinctly, the fabricated MOF-based sensor displays the required stability toward NH , enhanced sensitivity, and notable selectivity for NH gas. At room temperature and 68 % RH, it gives a remarkable gas response of 8620 % to 130 ppm NH gas and lower detection limit of 2 ppm towards NH gas. It is also found that the gas response of the ammonia sensor increases linearly with the increase of NH gas concentration under 68-98 % RH and room temperature. Moreover, the sensor indicates excellent reversibility and selectivity toward NH versus N , H , O , CO, CO , benzene, and MeOH. Based on structural analyses, activation energy calculations, water and NH vapor absorptions, and PXRD determinations, proton conduction and NH sensing mechanisms are suggested.

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“…A distinct feature of MOFs distinguishing them from other porous materials is the commonly‐encountered framework dynamics . The structures of some MOFs can expand or contract in the presence of external stimuli such as hydrolytic pressure, guest molecules in the frameworks, temperature, and light.…”

Section: Metal–organic Framework For Adsorptive Light Olefin/paraffimentioning

confidence: 53%

“…This is because the framework topologies, pore sizes, and functionalities of MOFs can be readily adjusted by crystal engineering to cater to various separation processes compared to other adsorbents such as carbon molecular sieves (CMS) and zeolites. The mechanisms behind olefin/paraffin separations in MOFs are basically the same as those in zeolites, except that adsorbent‐induced gate‐opening effects are more commonly encountered and utilized in MOF‐based gas separation . In addition, some MOFs can selectively adsorb alkanes over alkenes with decent gas selectivity and uptakes, contrasting zeolites which are predominantly olefin‐selective.…”

Section: Metal–organic Framework For Adsorptive Light Olefin/paraffimentioning

confidence: 99%

Alternatives to Cryogenic Distillation: Advanced Porous Materials in Adsorptive Light Olefin/Paraffin Separations

Wang

Peh

Zhao

2019

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As primary feedstocks in the petrochemical industry, light olefins such as ethylene and propylene are mainly obtained from steam cracking of naphtha and short chain alkanes (ethane and propane). Due to their similar physical properties, the separations of olefins and paraffins—pivotal processes to meet the olefin purity requirement of downstream processing—are typically performed by highly energy‐intensive cryogenic distillation at low temperatures and high pressures. To reduce the energy input and save costs, adsorptive olefin/paraffin separations have been proposed as promising techniques to complement or even replace cryogenic distillation, and growing efforts have been devoted to developing advanced adsorbents to fulfill this challenging task. In this Review, a holistic view of olefin/paraffin separations is first provided by summarizing how different processes have been established to leverage the differences between olefins and paraffins for effective separations. Subsequently, recent advances in the development of porous materials for adsorptive olefin/paraffin separations are highlighted with an emphasis on different separation mechanisms. Last, a perspective on possible directions to push the limit of the research in this field is presented.

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Flexibility in Metal–Organic Frameworks: A fundamental understanding

Cited by 191 publications

References 190 publications

Evaluation of the BET Theory for the Characterization of Meso and Microporous MOFs

Evaluation of the BET Theory for the Characterization of Meso and Microporous MOFs

A Highly Stable Two‐Dimensional Copper(II) Organic Framework for Proton Conduction and Ammonia Impedance Sensing

Alternatives to Cryogenic Distillation: Advanced Porous Materials in Adsorptive Light Olefin/Paraffin Separations

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