Shaping of Flexible Metal‐Organic Frameworks: Combining Macroscopic Stability and Framework Flexibility

Abstract

A facile extrusion approach that can fully retain the breathing behavior of flexible metal‐organic frameworks (MOF) like MIL‐53 and MIL‐53‐NH 2 employing methyl cellulose as binder is reported. Shaped MOF extrudates were extensively characterized by nitrogen sorption, X‐ray diffraction, thermogravimetric analysis and scanning electron microscopy. A detailed study on the mechanical stability of MIL‐53 extrudates with different amounts of binder reveals an increase in stability at low binder fractions while the maximum in attainable stability is reached at 5 wt.‐% binder. In‐situ XRD studies in CO 2 atmosphere and under humid conditions, respectively, demonstrate the reversibility in breathing behavior of the MIL‐53 extrudates without affecting the phase transition kinetics. High‐pressure methane and carbon dioxide isotherms on MIL‐53 and MIL‐53‐NH 2 extrudates exhibit loadings that are comparable to the uptake of the pristine powder. The shaping approach reported herein paves the way for using flexible MOF structures in technical applications.