Porous liquids based on UiO-66@SiO₂ through the strategy of growing an ultrathin silica layer for CO₂ selective separation

Porous liquids, a new type of materials that combine the permanent cavities of porous solids with the fluidity of liquids, have demonstrated broad applications in gas sorption and separation. However, their gas capture and separation performance often falls short compared with their corresponding advanced porous materials (APMs), primarily due to the direct interaction between the pore generators and the sterically hindered solvents. To address this issue, we here proposed a new strategy to transform the direct non-covalent interfacial interaction into an indirect non-covalent interfacial interaction by growing an ultrathin SiO₂ shell on the surface of UiO-66, thereby protecting its cavities. Experimental results confirm that the SiO₂ shell effectively preserves the porous cavities, leading to a higher CO₂ sorption ability for the resultant porous liquids compared to pristine sterically hindered solvent, and demonstrating potential for CO₂/N₂ selective separation. This innovative strategy not only offers a new approach for preparing porous liquids based on other advanced porous materials (e.g., MOFs, zeolites) but also provides a new horizon to enhance the gas sorption and separation efficiency of porous liquids.