Materials Science

Towards General Network Architecture Design Criteria for Negative Gas Adsorption Transitions in Ultraporous Frameworks

Abstract

Critical design criteria for negative gas adsorption (NGA), a counterintuitive feature of pressure amplifying materials, hitherto uniquely observed in a highly porous framework compound (DUT-49), are derived by analysing the physical effects of micromechanics, pore size, interpenetration, adsorption enthalpies, and the pore filling mechanism using advanced in situ X-ray and neutron diffraction, NMR spectroscopy, and calorimetric techniques parallelized to adsorption for a series of six isoreticular networks. Aided by computational modelling, we identify DUT-50 as a new pressure amplifying material featuring distinct NGA transitions upon methane and argon adsorption. In situ neutron diffraction analysis of the methane (CD4) adsorption sites at 111 K supported by grand canonical Monte Carlo simulations reveals a sudden population of the largest mesopore to be the critical filling step initiating structural contraction and NGA. In contrast, interpenetration leads to framework stiffening and specific pore volume reduction, both factors effectively suppressing NGA transitions.

Content

Thumbnail image of Krause et al - Towards NGA design - manuscript.pdf

Supplementary material

Thumbnail image of Krause et al. Supplementary video.gif
Krause et al. Supplementary video
Thumbnail image of MOF-FF optimized simulated structures.zip
MOF-FF optimized simulated structures
Thumbnail image of SCXRD-cif.zip
SCXRD-cif
Thumbnail image of Krause et al - Towards NGA design - ESI.pdf
Krause et al - Towards NGA design - ESI

Supplementary weblinks