Multivariate Flexible Framework with High Usable Hydrogen Capacity in a Reduced Pressure Swing Process

Published

April 12, 2023

Author(s)

Arijit Halder, Ryan Klein, Sarah Shulda, Gavin McCarver, Philip Parilla, Hiroyasu Furukawa, Craig Brown, C. Michael McGuirk

Abstract

Step-shaped adsorption¬–desorption of gaseous payloads by a flexible metal–organic framework can facilitate the delivery of large usable capaci-ties with significantly reduced energetic penalties. This is desirable for the storage, transport, and delivery of H2, as prototypical adsorbents require large swings in both pressure and temperature to achieve usable capacities approaching their total capacities. However, the weak physisorption of H2 typically necessitates undesirably high pressures to induce the framework phase change. As de no-vo design of flexible frameworks is exceedingly challenging, the ability to intuitively adapt known frameworks is desiredrequired. We demonstrate that the multivariate linker approach is a power-ful tool for tuning the phase change behavior of a flexible framework. In this work, 2–methyl–5,6–difluorobenzimidazolate was solvothermally in-corporated into the known framework CdIF-13 (sod–Cd(benzimidazolate)2), resulting in the mul-tivariate framework sod–Cd(benzimidazolate)1.87(2–methyl–5,6–difluorobenzimidazolate)0.13 (ratio = 14:1) which exhibited a considerably reduced stepped adsorp-tion threshold pressure while maintaining the de-sirable adsorption–desorption profile and capacity of CdIF-13. At 77 K, the multivariate framework exhibits stepped H2 adsorption with saturation below 50 bar, and minimal desorption hysteresis at 5 bar. At 87 K, saturation of step-shaped ad-sorption occurs by 90 bar, with hysteresis closing at 30 bar. These adsorption–desorption profiles enable usable capacities in a mild pressure swing process above 1 wt%, representing 85–92% of the total capacities. This work demonstrates that the desirable performance of flexible frameworks can be readily adapted through the multivariate ap-proach to enable efficient storage and delivery of weakly physisorbing species.

Citation

Journal of the American Chemical Society

Volume

145

Issue

14

Pub Type

Journals

Download Paper

https://doi.org/10.1021/jacs.3c00344

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Keywords

Flexible MOF, hydrogen storage, synchrotron powder X-ray diffraction, isotherms, density functional theory calculations

Citation

Halder, A. , Klein, R. , Shulda, S. , McCarver, G. , Parilla, P. , Furukawa, H. , Brown, C. and McGuirk, C. (2023), Multivariate Flexible Framework with High Usable Hydrogen Capacity in a Reduced Pressure Swing Process, Journal of the American Chemical Society, [online], https://doi.org/10.1021/jacs.3c00344, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=936034 (Accessed April 27, 2024)