Polymer-aided microstructuring of moisture-stable GO-hybridized MOFs for carbon dioxide capture

Abstract

MOF-based hybrid adsorbents for carbon capture are gaining increased attention as they can enhance key performance properties and scalability of MOFs. Yet, structuring these complex materials into mm-sized shaped particles to be used in actual process while maintaining the performance characteristics of the original powdered hybrids is challenging. In this work, a water-stable MOF (MIL-101(Cr)) was hybridized with graphene oxide (GO) yielding a hybrid adsorbent with enhanced CO2 capture performance, and the hybrid was then structured into mechanically robust spherical polyacrylonitrile-based beads of ∼ 2–3 mm in size exhibiting hierarchical porosity and high MOF loading (up to 80%) using a novel, simple, and scalable strategy. The powdered hybrid adsorbent with an optimum GO loading of 6 wt.% exhibited a 55% higher CO2 adsorption capacity and a 48% higher CO2/N2 selectivity than those of the parent MOF at 298 K and 1 bar, while the structured analogue provided high dispersion of the MOF@GO powder and preserved the CO2 adsorption performance and porosity characteristics of the original MOF@GO, making the resulting beads suitable and ready-to-use for practical CO2 capture application.