Design and Preparation of a Core–Shell Metal–Organic Framework for Selective CO2 Capture

The design of a core-shell metal-organic framework comprising a porous bio-MOF-11/14 mixed core and a less porous bio-MOF-14 shell is reported. The growth of the MOF shell was directly observed and supported by SEM and PXRD. The resulting core-shell material exhibits 30% higher CO2 uptake than bio-MOF-14 and low N2 uptake in comparison to the core. When the core-shell architecture is destroyed by fracturing the crystallites via grinding, the amount of N2 adsorbed doubles but the CO2 adsorption capacity remains the same. Finally, the more water stable bio-MOF-14 shell serves to prevent degradation of the water-sensitive core in aqueous environments, as evidenced by SEM and PXRD.