Formulation of Metal–Organic Framework Inks for the 3D Printing of Robust Microporous Solids toward High-Pressure Gas Storage and Separation

Abstract : Shaping of metal-organic frameworks (MOFs) has become increasingly studied over the past few years because it represents a major bottleneck toward their further applications at larger scale. MOF-based macroscale solids should present similar performances to their powder counterparts along with adequate mechanical resistance. 3D printing is one of the promising technologies as it allows the fast prototyping of materials at the macroscale; however, the large amounts of added binders have a detrimental effect on the porous properties of the solids. Herein, a 3D printer was modified to prepare a variety of MOF-based solids with controlled morphology from shear-thinning inks containing 2-hydroxyethyl cellulose. Four benchmark MOFs were tested for this purpose: HKUST-1, CPL-1, ZIF-8 and UiO-66-NH2. All solids are mechanically stable up to 0.6 MPa of uniaxial compression and highly porous with BET specific surface areas lowered by 0 to -25%. Furthermore, these solids were applied to high pressure hydrocarbon sorption (CH4, C2H4 and C2H6) and presented consequent gravimetric uptake and highly preferential adsorption.