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Hydrogen Adsorption in Metal–Organic Framework MIL-101(Cr)—Adsorbate Densities and Enthalpies from Sorption, Neutron Scattering, In Situ X-ray Diffraction, Calorimetry, and Molecular Simulations: ACS Applied Energy Materials

Hydrogen Adsorption in Metal–Organic Framework MIL-101(Cr)—Adsorbate Densities and Enthalpies from Sorption, Neutron Scattering, In Situ X-ray Diffraction, Calorimetry, and Molecular Simulations: ACS Applied Energy Materials
Hydrogen Adsorption in Metal–Organic Framework MIL-101(Cr)—Adsorbate Densities and Enthalpies from Sorption, Neutron Scattering, In Situ X-ray Diffraction, Calorimetry, and Molecular Simulations: ACS Applied Energy Materials

In this paper, hydrogen adsorption in metal-organic framework MIL-101(Cr) is investigated through a combination of sorption experiments, modeling of experimental isotherms, differential scanning calorimetry (DSC), neutron scattering, in situ synchrotron powder X-ray diffraction, and molecular simulations. The molecular simulations at 77 K for H2 adsorption in the material show excellent correspondence with excess uptakes determined from experimental isotherms. The simulations also indicate that H2 adsorption at a low pressure is mainly located in the 0.7 nm supertetrahedron and that, with increasing pressure, H2 starts to accumulate in the small (2.9 nm) and large (3.4 nm) cages. The inelastic neutron scattering results show that, in contrast to reports for hydrogen adsorption under the same conditions for microporous carbons, there is no solid-like H2 or any higher density H2 phases adsorbed in the pores of MIL-101(Cr). This indicates that, with increasing pressures, the adsorbed density of the MIL-101(Cr) remains constant but the volume of adsorbate increases and that higher densities for adsorbed hydrogen require pore sizes smaller than 0.7 nm, which is the size of the smallest pore in MIL-101(Cr). The enthalpies of adsorption are also investigated for this material using simulations, the Clapeyron equation applied to the isosteres and DSC, with the direct calorimetric method showing good agreement at zero coverage with the other two methods. The simulations and the Clapeyron equation are also in good agreement up to 6 wt % coverage.

MIL-101(Cr), adsorbed density, enthalpies of adsorption, hydrogen storage, inelastic neutron scattering, metal-organic frameworks
7839-7847
Bimbo, Nuno
53d9fc24-e2c1-4e2d-8d75-8dc640d8adda
Zhang, Kang
54807fa5-c3d2-442f-8cc4-95b4a00760cd
Aggarwal, Himanshu
595f81b1-034e-4412-b632-b957b6b932e0
Mays, Timothy J.
d02351c7-1d8f-4a9e-8d16-675c1f7b3635
Jiang, Jianwen
66b095d6-8144-4f09-8d57-58309eaf1e6e
Barbour, Leonard J.
7f70bafd-ac1d-4be9-abdf-35d0a871f757
Ting, Valeska P.
d4381878-2aad-4a3f-a7cc-021a7f7075eb
Bimbo, Nuno
53d9fc24-e2c1-4e2d-8d75-8dc640d8adda
Zhang, Kang
54807fa5-c3d2-442f-8cc4-95b4a00760cd
Aggarwal, Himanshu
595f81b1-034e-4412-b632-b957b6b932e0
Mays, Timothy J.
d02351c7-1d8f-4a9e-8d16-675c1f7b3635
Jiang, Jianwen
66b095d6-8144-4f09-8d57-58309eaf1e6e
Barbour, Leonard J.
7f70bafd-ac1d-4be9-abdf-35d0a871f757
Ting, Valeska P.
d4381878-2aad-4a3f-a7cc-021a7f7075eb

Bimbo, Nuno, Zhang, Kang, Aggarwal, Himanshu, Mays, Timothy J., Jiang, Jianwen, Barbour, Leonard J. and Ting, Valeska P. (2021) Hydrogen Adsorption in Metal–Organic Framework MIL-101(Cr)—Adsorbate Densities and Enthalpies from Sorption, Neutron Scattering, In Situ X-ray Diffraction, Calorimetry, and Molecular Simulations: ACS Applied Energy Materials. ACS Applied Energy Materials, 4 (8), 7839-7847. (doi:10.1021/acsaem.1c01196).

Record type: Article

Abstract

In this paper, hydrogen adsorption in metal-organic framework MIL-101(Cr) is investigated through a combination of sorption experiments, modeling of experimental isotherms, differential scanning calorimetry (DSC), neutron scattering, in situ synchrotron powder X-ray diffraction, and molecular simulations. The molecular simulations at 77 K for H2 adsorption in the material show excellent correspondence with excess uptakes determined from experimental isotherms. The simulations also indicate that H2 adsorption at a low pressure is mainly located in the 0.7 nm supertetrahedron and that, with increasing pressure, H2 starts to accumulate in the small (2.9 nm) and large (3.4 nm) cages. The inelastic neutron scattering results show that, in contrast to reports for hydrogen adsorption under the same conditions for microporous carbons, there is no solid-like H2 or any higher density H2 phases adsorbed in the pores of MIL-101(Cr). This indicates that, with increasing pressures, the adsorbed density of the MIL-101(Cr) remains constant but the volume of adsorbate increases and that higher densities for adsorbed hydrogen require pore sizes smaller than 0.7 nm, which is the size of the smallest pore in MIL-101(Cr). The enthalpies of adsorption are also investigated for this material using simulations, the Clapeyron equation applied to the isosteres and DSC, with the direct calorimetric method showing good agreement at zero coverage with the other two methods. The simulations and the Clapeyron equation are also in good agreement up to 6 wt % coverage.

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Accepted/In Press date: 28 July 2021
Published date: 23 August 2021
Additional Information: Funding Information: The authors would like to thank the Engineering and Physical Sciences Research Council (EPSRC) for a Fellowship (EP/R01660X/1) and for Hydrogen and Fuel Cells SUPERGEN Hub projects (EP/E040071/1, EP/K021109/1, EP/L018365/1, and EP/J016454/1), STFC for the allocation of ISIS beamtime (proposal number RB1320122), ESRF for allocation of time for in situ X-ray diffraction on ID31 (MA-1761), and the University of Bath for International Mobility Funding to visit Stellenbosch University. Publisher Copyright: © 2021 American Chemical Society. All rights reserved.
Keywords: MIL-101(Cr), adsorbed density, enthalpies of adsorption, hydrogen storage, inelastic neutron scattering, metal-organic frameworks

Identifiers

Local EPrints ID: 450930
URI: http://eprints.soton.ac.uk/id/eprint/450930
PURE UUID: 690d60ff-d3c0-4547-b0b1-e3707e0f7e1f
ORCID for Nuno Bimbo: ORCID iD orcid.org/0000-0001-8740-8284

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Date deposited: 24 Aug 2021 17:01
Last modified: 17 Mar 2024 03:59

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Contributors

Author: Nuno Bimbo ORCID iD
Author: Kang Zhang
Author: Himanshu Aggarwal
Author: Timothy J. Mays
Author: Jianwen Jiang
Author: Leonard J. Barbour
Author: Valeska P. Ting

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