Advances in Shaping of Metal-Organic Frameworks for CO2 Capture: Understanding the Effect of Rubbery and Glassy Polymeric Binders

Abstract

Development of advanced CO2 capture physical adsorbents in powdered form is a key step, nevertheless their transformation into particulates is a process of paramount importance for their deployment and implementation in the real-world applications. Herein we report a facile and quick shaping process of one of the best solid-state materials from the class of metal-organic frameworks (MOFs) for CO2 capture at a concentration below 15%, that is, NbOFFIVE-1-Ni driven mainly by strong but purely physical based adsorption. Purposely, NbOFFIVE-1-Ni powders were transformed into shaped bodies using select polymers as binders and their associated CO2 capture properties were thoroughly evaluated before and after shaping. Markedly, we have selected two distinct polymers, namely a rubbery polymer (polyethelyneglycol = PEG) and a glassy polymer (poly(methyl methacrylate) = PMMA). To corroborate the universality of our shaping strategy, we indeed successfully made MOF beads with high mechanical stability based on well-known MOFs like UiO-66, ZIF-8, and HKUST-1. Prominently, the results show that the glassy polymer is a better binder than the rubbery polymer, offering the requisite high mechanical stability with comparatively minimal alteration in gas adsorption upon loading of 10% polymer.