Investigating H 2 Adsorption in Isostructural Metal-Organic Frameworks M-CUK-1 (M = Co and Mg) through Experimental and Theoretical Studies.

Autor: Suepaul S; Department of Chemistry, University of South Florida, 4202 East Fowler Avenue, CHE205, Tampa, Florida 33620-5250, United States., Forrest KA; Department of Chemistry, University of South Florida, 4202 East Fowler Avenue, CHE205, Tampa, Florida 33620-5250, United States., Georgiev PA; Department for Solid State Physics and Microelectronics, Faculty of Physics, University of Sofia, 5 James Bourchier Boulevard, Sofia 1164, Bulgaria., Forster PM; Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Nevada 89154, United States., Lohstroh W; Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München, Lichtenbergstraße 1, D-85748 Garching, Germany., Grzimek V; Helmholtz-Zentrum Berlin, für Materialien und Energie, Lise-Meitner Campus, Hahn-Meitner-Platz 1, 14109 Berlin, Germany., Dunning SG; Department of Chemistry, The University of Texas at Austin, Welch Hall 4.428, 105 East 24th Street, Stop A5300, Austin, Texas 78712-1224, United States., Reynolds JE 3rd; Department of Chemistry, The University of Texas at Austin, Welch Hall 4.428, 105 East 24th Street, Stop A5300, Austin, Texas 78712-1224, United States., Humphrey SM; Department of Chemistry, The University of Texas at Austin, Welch Hall 4.428, 105 East 24th Street, Stop A5300, Austin, Texas 78712-1224, United States., Eckert J; Department of Chemistry, University of South Florida, 4202 East Fowler Avenue, CHE205, Tampa, Florida 33620-5250, United States.; Department of Chemistry and Biochemistry, Texas Tech University, 2500 Broadway, Box 41 061, Lubbock, Texas 79409-1061, United States., Space B; Department of Chemistry, University of South Florida, 4202 East Fowler Avenue, CHE205, Tampa, Florida 33620-5250, United States.; Department of Chemistry, North Carolina State University, 2700 Stinson Drive, Cox Hall 506, Raleigh, North Carolina 27607, United States., Pham T; Department of Chemistry, University of South Florida, 4202 East Fowler Avenue, CHE205, Tampa, Florida 33620-5250, United States.
Jazyk: angličtina
Zdroj: ACS applied materials & interfaces [ACS Appl Mater Interfaces] 2022 Feb 16; Vol. 14 (6), pp. 8126-8136. Date of Electronic Publication: 2022 Feb 04.
DOI: 10.1021/acsami.1c20312
Abstrakt: A combined experimental and theoretical study of H 2 adsorption was carried out in Co-CUK-1 and Mg-CUK-1, two isostructural metal-organic frameworks (MOFs) that consist of M 2+ ions (M = Co and Mg) coordinated to pyridine-2,4-dicarboxylate (pdc 2- ) and OH - ligands. These MOFs possess saturated metal centers in distorted octahedral environments and narrow pore sizes and display high chemical and thermal stability. Previous experimental studies revealed that Co-CUK-1 exhibits a H 2 uptake of 183 cm 3 g -1 at 77 K/1.0 atm [ Angew. Chem., Int. Ed. 2007, 46, 272-275, DOI: 10.1002/anie.200601627], while that for Mg-CUK-1 under the same conditions is 240 cm 3 g -1 on the basis of the experimental measurements carried out herein. The theoretical H 2 adsorption isotherms are in close agreement with the corresponding experimental measurements for simulations using electrostatic and polarizable potentials of the adsorbate. Through simulated annealing calculations, it was found that the primary binding site for H 2 in both isostructural analogues is localized proximal to the center of the aromatic rings belonging to the pdc 2- linkers. Inelastic neutron scattering (INS) spectroscopic studies of H 2 adsorbed in both MOFs revealed a rotational tunnelling transition occurring at around 8 meV in the corresponding spectra; this peak represents H 2 adsorbed at the primary binding site. Two-dimensional quantum rotation calculations for H 2 localized at the primary and secondary binding sites in both MOFs yielded rotational energy levels that are in agreement with the transitions observed in the INS spectra. Even though both M-CUK-1 analogues possess different metal ions, they exhibit similar electrostatic environments, modeled structures at H 2 saturation, and rotational potentials for H 2 adsorbed at the most favorable adsorption site. Overall, this study demonstrates how important molecular-level details of the H 2 adsorption mechanism inside MOF micropores can be derived from a combination of experimental measurements and theoretical calculations using two stable and isostructural MOFs with saturated metal centers and small pore windows as model systems.
Databáze: MEDLINE