Tailoring the separation properties of flexible metal-organic frameworks using mechanical pressure

N. Chanut (1) , Aziz Ghoufi (2) , M.-V. Coulet (1) , S. Bourrelly (1) , B. Kuchta (1) , Guillaume Maurin (3) , P.L. Llewellyn (1)

1 MADIREL - Matériaux divisés, interfaces, réactivité, électrochimie
2 IPR - Institut de Physique de Rennes
3 ICGM - Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier

Metal-organic frameworks are widely considered for the separation of chemical mixtures due to their adjustable physical and chemical properties. However, while much effort is currently devoted to developing new adsorbents for a given separation, an ideal scenario would involve a single adsorbent for multiple separations. Porous materials exhibiting framework flexibility offer unique opportunities to tune these properties since the pore size and shape can be controlled by the application of external stimuli. Here, we establish a proof-of-concept for the molecular sieving separation of species with similar sizes (CO2/N2 and CO2/CH4), via precise mechanical control of the pore size aperture in a flexible metal-organic framework. Besides its infinite selectivity for the considered gas mixtures, this material shows excellent regeneration capability when releasing the external mechanical constraint. This strategy, combining an external stimulus applied to a structurally compliant adsorbent, offers a promising avenue for addressing some of the most challenging gas separations. © 2020, The Author(s).

Keywords: adsorption; mechanical control; molecular analysis; physicochemical property; pore space; regeneration; separation; sieving

Domains: Physics [physics]

N. Chanut, Aziz Ghoufi, M.-V. Coulet, S. Bourrelly, B. Kuchta, et al.. Tailoring the separation properties of flexible metal-organic frameworks using mechanical pressure. Nature Communications, 2020, 11 (1), pp.1216. ⟨10.1038/s41467-020-15036-y⟩. ⟨hal-02535641⟩