Adsorption-based
capture of CO2from flue gas and from
air requires materials that have a high affinity for CO2and can resist water molecules that competitively bind to adsorption
sites. Here, we present a core–shell metal–organic framework
(MOF) design strategy where the core MOF is designed to selectively
adsorb CO2, and the shell MOF is designed to block H2O diffusion into the core. To implement and test this strategy,
we used the zirconium (Zr)-based UiO MOF platform because of its relative
structural rigidity and chemical stability. Previously reported computational
screening results were used to select optimal core and shell MOF compositions
from a basis set of possible building blocks, and the target core–shell
MOFs were prepared. Their compositions and structures were characterized
using scanning electron microscopy, transmission electron microscopy,
and powder X-ray diffraction. Multigas (CO2, N2, and H2O) sorption data were collected both for the core–shell
MOFs and for the core and shell MOFs individually. These data were
compared to determine whether the core–shell MOF architecture
improved the CO2capture performance under humid conditions.
The combination of experimental and computational results demonstrated
that adding a shell layer with high CO2/H2O
diffusion selectivity can significantly reduce the effect of water
on CO2uptake.