Fabrication of highly CO2/N2 selective polycrystalline UiO-66 membrane with two-dimensional transition metal dichalcogenides as zirconium source via tertiary solvothermal growth

Zirconium-based MOF (Zr-MOF) membranes have attracted widespread attention due to their highly tailorable pore aperture and adsorption behavior achieved by functional group decoration and ligand/cluster-missing defect regulation as well as extraordinary chemical/thermal stability. Nevertheless, it has remained a great challenge to further improve the separation performance of Zr-MOF membranes due to very limited available zirconium sources and heating modes. In this study, we prepared polycrystalline UiO-66 membranes exhibiting unprecedented CO 2 /N 2 selectivity (31.3). The use of layered ZrS 2 , a representative of transition-metal dichalcogenides (TMDCs), as zirconium source during tertiary solvothermal growth was found to be indispensable for improving the separation performance of UiO-66 membranes. As far as we know, the CO 2 /N 2 selectivity reported in this study was the highest among all pristine polycrystalline MOF membranes measured under ambient conditions. More importantly, our study highlighted the importance of concurrent metal source and fabrication process innovation in performance enhancement of polycrystalline MOF membranes.