CO<sub>2</sub> Adsorption in a Robust Iron(III) Pyrazolate-Based MOF: Molecular-Level Details and Frameworks Dynamics From Powder X-ray Diffraction Adsorption Isotherms.

Vismara, Rebecca; Terruzzi, Stephanie; Maspero, Angelo; Grell, Toni; Bossola, Filippo; Sironi, Angelo; Galli, Simona; Navarro, Jorge A R et al. · Adv Mater · 2024

basic_science · Level V

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Abstract

Understanding adsorption processes at the molecular level, with multi-technique approaches, is nowadays at the frontier of porous materials research. In this work it is shown that with a proper data treatment, in situ high-resolution powder X-ray diffraction (HR-PXRD) at variable temperature and gas pressure can reveal atomic details of the accommodation sites, the framework dynamics as well as thermodynamic information (isosteric heat of adsorption) of the CO<sub>2</sub> adsorption process in the robust iron(III) pyrazolate-based MOF Fe<sub>2</sub>(BDP)<sub>3</sub> [H<sub>2</sub>BDP = 1,4-bis(1H-pyrazol-4-yl)benzene]. Highly reliable "HR-PXRD adsorption isotherms" can be constructed from occupancy values of CO<sub>2</sub> molecules. The "HR-PXRD adsorption isotherms" accurately match the results of conventional static and dynamic gas sorption experiments and Monte Carlo simulations. These results are indicative of the impact of the molecular-level behavior on the bulk properties of the system under study and of the potential of the presented multi-technique approach to understand adsorption processes in metal-organic frameworks.