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 they are generally made of is not suitable, mainly because of the low packing density. Powder compaction is therefore necessary, but also challenging because of its typical mechanical fragility. Indeed, generally, MOF powders undergo irreversibly damages upon densification processes, for example partially or totally loosing microporosity and catalytic activity. In this work, we have deeply studied 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, by contrast, STAM-17-OEt is extremely suitable for mechanical compaction processes with pressures up to 200 MPa, which increase its packing density and its catalytic activity, and then also preserve the characteristic porosity, flexibility and water stability of STAM-17-OEt. The results are supported by many experimental techniques including EPR spectroscopy, PXRD diffraction, CO2 isotherms studies and catalytic tests.