Drastic enhancement of the CO2 adsorption properties in sulfone-functionalized Zr- and Hf-UiO-67 MOFs with hierarchical mesopores.

The sulfone-functionalized Zr- and Hf-UiO-67 metal-organic frameworks with hierarchical mesopores were successfully synthesized using the ligand 4,4'-dibenzoic acid-2,2'-sulfone, with acetic acid or HCl as the modulator. Compared to UiO-67, the zirconium solid shows a remarkable 122% increase in CO2 uptake, reaching 4.8 mmol g(-1) (17.4 wt %) at 1 bar and 273 K (145% at 298 K) and more than 100% increase in CO2/CH4 selectivity.

A straight forward route for the development of metal-organic frameworks functionalized with aromatic -OH groups: synthesis, characterization, and gas (N2, Ar, H2, CO2, CH4, NH3) sorption properties.

A facile and general methodology for the development of metal-organic frameworks (MOFs) functionalized with pendant, aromatic hydroxyl (-OH) groups is presented. Extensive gas-sorption studies in representative and important MOFs functionalized with free aromatic -OH groups such as the IRMOF-8 and DUT-6 (or MOF-205), denoted here as 1 and 2, revealed a high CO(2)/CH(4) selectivity for 1 (13.6 at 273 K and 1 bar) and a high NH(3) uptake of 16.4 mol kg(-1) at 298 K and 1 bar for 2.