Structure effects induced by high mechanical compaction of STAM-17-OEt MOF powders

Abstract

Metal-organic frameworks (MOFs) are promising materials for many potential applications, spacing from gas storage to catalysis. However, the powder form of which they are generally made is not suitable, mainly because of the low packing density. Powder compaction is therefore necessary, but also challenging because of their typical mechanical fragility. Indeed, generally, they undergo irreversibly damages upon densification processes, for example partially or totally loosing microporosity and catalytic activity. In this work, we deeply study the compaction effects on the flexible Cu(II)-based MOF STAM-17-OEt (Cu(C10O5H8)1.6 H2O), whose chemical composition is close to that of HKUST-1, obtaining that it is, by contrast, extremely suitable for mechanical compaction processes with pressures up to 200 MPa, which increase its packing density, its catalytic activity, and preserve porosity, flexibility and water stability, characteristics of STAM-17-OEt. The results are supported by many experimental techniques including EPR spectroscopy, PXRD diffraction, CO2 isotherms studies and catalytic tests.