Vapor-assisted self-conversion of basic carbonates in metal–organic frameworks

Nanoscale ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 5069-5076
Author(s):  
Miaomiao Jia ◽  
Jingyi Su ◽  
Pengcheng Su ◽  
Wanbin Li

Basic carbonates with high alkalinity are incorporated into metal–organic frameworks by solvent vapor-assisted self-conversion of partial metal centers to improve carbon capture performance.

2019 ◽  
Author(s):  
Andrew Rosen ◽  
M. Rasel Mian ◽  
Timur Islamoglu ◽  
Haoyuan Chen ◽  
Omar Farha ◽  
...  

<p>Metal−organic frameworks (MOFs) with coordinatively unsaturated metal sites are appealing as adsorbent materials due to their tunable functionality and ability to selectively bind small molecules. Through the use of computational screening methods based on periodic density functional theory, we investigate O<sub>2</sub> and N<sub>2</sub> adsorption at the coordinatively unsaturated metal sites of several MOF families. A variety of design handles are identified that can be used to modify the redox activity of the metal centers, including changing the functionalization of the linkers (replacing oxido donors with sulfido donors), anion exchange of bridging ligands (considering μ-Br<sup>-</sup>, μ-Cl<sup>-</sup>, μ-F<sup>-</sup>, μ-SH<sup>-</sup>, or μ-OH<sup>-</sup> groups), and altering the formal oxidation state of the metal. As a result, we show that it is possible to tune the O<sub>2</sub> affinity at the open metal sites of MOFs for applications involving the strong and/or selective binding of O<sub>2</sub>. In contrast with O<sub>2</sub> adsorption, N<sub>2</sub> adsorption at open metal sites is predicted to be relatively weak across the MOF dataset, with the exception of MOFs containing synthetically elusive V<sup>2+</sup> open metal sites. As one example from the screening study, we predict that exchanging the μ-Cl<sup>-</sup> ligands of M<sub>2</sub>Cl<sub>2</sub>(BBTA) (H<sub>2</sub>BBTA = 1<i>H</i>,5<i>H</i>-benzo(1,2-d:4,5-d′)bistriazole) with μ-OH<sup>-</sup> groups would significantly enhance the strength of O<sub>2</sub> adsorption at the open metal sites without a corresponding increase in the N<sub>2</sub> affinity. Experimental investigation of Co<sub>2</sub>Cl<sub>2</sub>(BBTA) and Co<sub>2</sub>(OH)<sub>2</sub>(BBTA) confirms that the former exhibits only weak physisorption, whereas the latter is capable of chemisorbing O<sub>2</sub> at room temperature. The chemisorption behavior is attributed to the greater electron-donating character of the μ-OH<sup>-</sup><sub> </sub>ligands and the presence of H-bonding interactions between the μ-OH<sup>-</sup> bridging ligands and the O<sub>2</sub> adsorbate.</p>


JACS Au ◽  
2021 ◽  
Author(s):  
Young Hun Lee ◽  
YongSung Kwon ◽  
Chaehoon Kim ◽  
Young-Eun Hwang ◽  
Minkee Choi ◽  
...  

2020 ◽  
Vol 40 ◽  
pp. 156-170 ◽  
Author(s):  
Ping Shao ◽  
Luocai Yi ◽  
Shumei Chen ◽  
Tianhua Zhou ◽  
Jian Zhang

Author(s):  
Kendric Roberts ◽  
Yen-Lin Han

Abstract In combatting human induced climate change, carbon capture provides the potential to more slowly ease away from the dependence on hydrocarbon fuel sources, while mitigating the amount of CO2 released into the atmosphere. One promising material to use is metal-organic frameworks (MOF’s). MOF’s offer an immense variety in potential exceptionally porous structures, a property important in separation. As a result of practical experimental measurements being expensive and time consuming, interest in accomplishing the same goal through modeling has also increased. Using density functional theory to optimize the approximate experimentally measured atomic geometries has been shown to have sufficient accuracy. A previous study by Nazarian et al. was performed to optimize structures on the CoRE MOF Database using a supercomputer. The purpose of this study was to attempt to replicate their work done with a single MOF using computational resources more commonly available. Furthermore, as time tends to be the limiting factor in conducting these studies, the use of a smearing function was adjusted for two optimizations to see if any considerable improvement on the efficiency of the optimizations could be made. Our results show both optimizations improved the bond length accuracy relative to the raw data compared with the optimization from Nazarian, et al. The optimization with a more present smearing effect was able to converge the electron field in roughly half the time, while still showing nearly the same results, except for slightly more variability in the bond lengths involving transition metals. Unfortunately, the improvement in bond length, did not correspond in consistent improvement of the larger cell defining metrics. This shows that either a different energy minimum was found or the relationship between the larger cell parameters, with the more local parameters such as bond length is too complex for the method to effectively solve.


Author(s):  
Ahmed I. Osman ◽  
Mahmoud Hefny ◽  
M. I. A. Abdel Maksoud ◽  
Ahmed M. Elgarahy ◽  
David W. Rooney

AbstractHuman activities have led to a massive increase in $$\hbox {CO}_{2}$$ CO 2 emissions as a primary greenhouse gas that is contributing to climate change with higher than $$1\,^{\circ }\hbox {C}$$ 1 ∘ C global warming than that of the pre-industrial level. We evaluate the three major technologies that are utilised for carbon capture: pre-combustion, post-combustion and oxyfuel combustion. We review the advances in carbon capture, storage and utilisation. We compare carbon uptake technologies with techniques of carbon dioxide separation. Monoethanolamine is the most common carbon sorbent; yet it requires a high regeneration energy of 3.5 GJ per tonne of $$\hbox {CO}_{2}$$ CO 2 . Alternatively, recent advances in sorbent technology reveal novel solvents such as a modulated amine blend with lower regeneration energy of 2.17 GJ per tonne of $$\hbox {CO}_{2}$$ CO 2 . Graphene-type materials show $$\hbox {CO}_{2}$$ CO 2 adsorption capacity of 0.07 mol/g, which is 10 times higher than that of specific types of activated carbon, zeolites and metal–organic frameworks. $$\hbox {CO}_{2}$$ CO 2 geosequestration provides an efficient and long-term strategy for storing the captured $$\hbox {CO}_{2}$$ CO 2 in geological formations with a global storage capacity factor at a Gt-scale within operational timescales. Regarding the utilisation route, currently, the gross global utilisation of $$\hbox {CO}_{2}$$ CO 2 is lower than 200 million tonnes per year, which is roughly negligible compared with the extent of global anthropogenic $$\hbox {CO}_{2}$$ CO 2 emissions, which is higher than 32,000 million tonnes per year. Herein, we review different $$\hbox {CO}_{2}$$ CO 2 utilisation methods such as direct routes, i.e. beverage carbonation, food packaging and oil recovery, chemical industries and fuels. Moreover, we investigated additional $$\hbox {CO}_{2}$$ CO 2 utilisation for base-load power generation, seasonal energy storage, and district cooling and cryogenic direct air $$\hbox {CO}_{2}$$ CO 2 capture using geothermal energy. Through bibliometric mapping, we identified the research gap in the literature within this field which requires future investigations, for instance, designing new and stable ionic liquids, pore size and selectivity of metal–organic frameworks and enhancing the adsorption capacity of novel solvents. Moreover, areas such as techno-economic evaluation of novel solvents, process design and dynamic simulation require further effort as well as research and development before pilot- and commercial-scale trials.


2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Mathieu Bosch ◽  
Muwei Zhang ◽  
Hong-Cai Zhou

Metal-organic frameworks (MOFs) are a new category of advanced porous materials undergoing study by many researchers for their vast variety of both novel structures and potentially useful properties arising from them. Their high porosities, tunable structures, and convenient process of introducing both customizable functional groups and unsaturated metal centers have afforded excellent gas sorption and separation ability, catalytic activity, luminescent properties, and more. However, the robustness and reactivity of a given framework are largely dependent on its metal-ligand interactions, where the metal-containing clusters are often vulnerable to ligand substitution by water or other nucleophiles, meaning that the frameworks may collapse upon exposure even to moist air. Other frameworks may collapse upon thermal or vacuum treatment or simply over time. This instability limits the practical uses of many MOFs. In order to further enhance the stability of the framework, many different approaches, such as the utilization of high-valence metal ions or nitrogen-donor ligands, were recently investigated. This review details the efforts of both our research group and others to synthesize MOFs possessing drastically increased chemical and thermal stability, in addition to exemplary performance for catalysis, gas sorption, and separation.


2016 ◽  
Vol 18 (11) ◽  
pp. 8075-8080 ◽  
Author(s):  
Sebastian Schwalbe ◽  
Kai Trepte ◽  
Gotthard Seifert ◽  
Jens Kortus

We present a first principles study of low-spin (LS)/high-spin (HS) screening for 3d metal centers in the metal organic framework (MOF) DUT-8(Ni).


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