Influence of Anion Composition on Gas Sorption Features of Cr-MIL-101 Metal–Organic Framework

Abstract

A series of chromium(III) terephthalates MIL-101 with different anion composition of the porous matrix have been synthesized and characterized in adsorption reactions with nitrogen, hydrogen, and methane by volumetric and calorimetric measurements at pressures up to 3.2 MPa. A peculiar local maximum of H2 adsorption heat at concentrations of 0.7–0.9 mmol/g corresponding to the filling of nanosized supertetrahedra was found. It has been shown that the substitution of the fluorine anions by Cl– strongly affected accessibility of these micropores toward gas molecules.