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.