Hydrogen Adsorption on Fe-based Metal Organic Frameworks: DFT Study

Agusta, Mohammad Kemal; Saputro, Adhitya Gandaryus; Tanuwijaya, Viny Veronika; Hidayat, Novianto Nur; Dipojono, Hermawan Kresno

doi:10.1016/j.proeng.2017.03.030

Cited by 16 publications

(9 citation statements)

References 6 publications

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“…In many chemisorption cases, normally, the trend of molecular adsorption can be properly explained by relating the trend of adsorption energy with the amount of charge transfer to/from the adsorbed molecule (Agusta, Saputro, Tanuwijaya, Hidayat, & Dipojono, 2017;Nugraha et al, 2016Nugraha et al, , 2017Rusydi, Agusta, Saputro, & Kasai, 2012;Adhitya G. Saputro & Kasai, 2014;Adhitya G. Saputro, Kasai, Asazawa, Kishi, & Tanaka, 2013;Adhitya G. Saputro et al, 2019). However, this procedure cannot be directly used in the current case since the amount of charge transfer in all BTEX adsorption cases are almost equivalent, and yet their adsorption energies are quite different.…”

Section: Resultsmentioning

confidence: 99%

Density Functional Study on Benzene, Toluene, Ethylbenzene and Xylene Adsorptions on ZnO(100) Surface

Nugraha

Saputro

Agusta

et al. 2019

Molekul

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We study the interaction between benzene, toluene, ethylbenzene and xylene (BTEX) molecules with ZnO(100) surface by means of density functional theory-based calculations. We find that these interactions result in the physical adsorptions of BTEX gases with adsorption distances larger than 2 Å. These adsorptions are governed by the van der Waals interaction instead of the covalent interaction. We also find that the trend of the strength of BTX adsorptions on ZnO(100) surface is in line with the experimental trend of sensitivity of ZnO material towards BTX gases (benzene < tolune < xylene). We explain this relation by using one of the sensing mechanism within the ionosorption model. By using this relation, we also predict that the response of ZnO towards ethylbenzene will be similar to the response towards toluene since these two molecules have similar adsorption energies on ZnO(100) surface.

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Section: Resultsmentioning

confidence: 99%

Density Functional Study on Benzene, Toluene, Ethylbenzene and Xylene Adsorptions on ZnO(100) Surface

Nugraha

Saputro

Agusta

et al. 2019

Molekul

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“…Further calculations such as NBO (Natural Bond Orbital) and estimation of the energy of the small model system were performed using G09 software, and AIM (Atoms in Molecules) analysis was performed using Multiwfn software [93] . Several DFT, coupled‐cluster and symmetry‐adapted perturbation theory‐based studies [65,66] are available in the literature exploring various aspects related to H 2 binding and uptake in MOFs [67–69] . The research frontier for hydrogen storage currently is how to store hydrogen at room temperature with a pressure swing.…”

Section: Computational Detailsmentioning

confidence: 99%

“…[93] Several DFT, coupled-cluster and symmetry-adapted perturbation theory-based studies [65,66] are available in the literature exploring various aspects related to H 2 binding and uptake in MOFs. [67][68][69] The research frontier for hydrogen storage currently is how to store hydrogen at room temperature with a pressure swing. As some of the binding site estimated here are purely dispersive type interactions, we have checked the corresponding binding energy for a possible basis set superposition errors, and the counterpoise correction performed for one of the sites reveal a minimum deviation (~0.7 kJ/mol, see ESI for further details).…”

Section: Computational Detailsmentioning

confidence: 99%

A Theoretical Perspective to Decipher the Origin of High Hydrogen Storage Capacity in Mn(II) Metal‐Organic Framework

2022

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Herein, we report a detailed periodic DFT investigation of Mn(II)-based [(Mn 4 Cl) 3 (BTT) 8 ] 3À (BTT 3À = 1,3,5-benzenetristetrazolate) metal-organic framework (MOF) to explore various hydrogen binding pockets, nature of MOF…H 2 interactions, magnetic coupling and, H 2 uptake capacity. Earlier experiments found an uptake capacity of 6.9 wt % of H 2, with the heat of adsorption estimated to be ~10 kJ/mol, which is one among the highest for any MOFs reported. Our calculations unveil different binding sites with computed binding energy varying from À 6 to À 15 kJ/mol. The binding of H 2 at the Mn 2 + site is found to be the strongest (site I), with H 2 found to bind Mn 2 + ion in a η 2 fashion with a distance of 2.27 Å and binding energy of À 15.4 kJ/mol. The bonding analysis performed using NBO and AIM reveal a strong donation of σ (H 2 ) to the d z 2 orbital of the Mn 2 + ion responsible for such large binding energy. The other binding pockets, such as À Cl (site II) and BTT ligands (site III and IV) were found to be weaker, with the binding energy decreasing in the order I > II > III > IV. The average binding energy computed for these four sites put together is 9.6 kJ/mol, which is in excellent agreement with the experimental value of ~10 kJ/mol. We have expanded our calculations to compute binding energy for multiple sites simultaneously, and in this model, the binding energy per site was found to decrease as we increased the number of H 2 molecules suggesting electronic and steric factors controlling the overall uptake capacity. The calculated adsorption isotherm using the GCMC method reproduces the experimental observations. Further, the magnetic coupling computed for the unbound MOF reveals moderate ferromagnetic and strong antiferromagnetic coupling within the tetrameric {Mn 4 } unit leading to a three-up-onedown spin configuration as the ground state. These were then coupled ferromagnetically to other tetrameric units in the MOF network. The magnetic coupling was found to alter only marginally upon gas binding, suggesting that both exchange interaction and the spin-states are unlikely to play a role in the H 2 uptake. This is contrary to the O 2 uptake studied lately, where strong dependence on exchange-coupling/spin state was witnessed, suggesting exchange-coupling/magnetic field dependent binding as a viable route for gas separation.

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“…[42][43][44] Or, the MOF properties can be approximated from just the SBU and simulated with a higher-level method. Such approximation of a MOF as a molecule has been widely adopted in previous studies for adsorption of gas molecules, [45][46][47][48][49][50][51] excited states, 52,53 and magnetic properties. 54 Nevertheless, a quantitative but also visually informative approach to determine when these approximations are valid would guide when this approximation is most valid.…”

Section: Spatial Distribution Of Mr Charactermentioning

confidence: 99%

DFT-based Multireference Diagnostics in the Solid State: Focusing on Metal-organic Frameworks

Cho

Nandy

Duan

et al. 2022

Preprint

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When a many-body wave function of a system deviates far from a single reference determinant, high-level multireference methods are required to properly explain the system. Multireference diagnostics to estimate the magnitude of such static correlation have been primarily developed for molecular systems, with a range of computational costs from low to as costly as the full multi-reference calculation itself. We report the first application of low-cost multireference diagnostics on the solid state based on the fractional occupation number calculated with finite-temperature density functional theory (DFT). In order to compare the behavior of the diagnostics on solids and molecules, we select metal-organic frameworks (MOFs) as model materials, since their reticular nature provides an intuitive way of identifying molecular derivatives. Two possible molecular fragmentations are considered: 1) breaking it down into its substituent secondary building unit and linker components and 2) extracting it in a finite cluster with a single metal atom. We demonstrate that the DFT-based multireference diagnostics are equally applicable to solids as to molecules. The magnitude and spatial distribution of the multireference character of a MOF are found to have a good correlation with those of the molecular derivatives, which can be calculated much more affordably in comparison to the full MOF. The additivity feature of the multireference character discussed here suggests molecular derivatives as a good representation of a MOF, facilitating accurate and efficient high throughput screening of MOFs and other porous solids.

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Hydrogen Adsorption on Fe-based Metal Organic Frameworks: DFT Study

Cited by 16 publications

References 6 publications

Density Functional Study on Benzene, Toluene, Ethylbenzene and Xylene Adsorptions on ZnO(100) Surface

Density Functional Study on Benzene, Toluene, Ethylbenzene and Xylene Adsorptions on ZnO(100) Surface

A Theoretical Perspective to Decipher the Origin of High Hydrogen Storage Capacity in Mn(II) Metal‐Organic Framework

DFT-based Multireference Diagnostics in the Solid State: Focusing on Metal-organic Frameworks

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