Metal–Organic Frameworks with Precisely Designed Interior for Carbon Dioxide Capture in the Presence of Water

The selective capture of carbon dioxide
in the presence of water
is an outstanding challenge. Here, we show that the interior of IRMOF-74-III
can be covalently functionalized with primary amine (IRMOF-74-III-CH2NH2) and used for the selective capture of CO2 in 65% relative humidity. This study encompasses the synthesis,
structural characterization, gas adsorption, and CO2 capture
properties of variously functionalized IRMOF-74-III compounds (IRMOF-74-III-CH3, -NH2, -CH2NHBoc, -CH2NMeBoc,
-CH2NH2, and -CH2NHMe). Cross-polarization
magic angle spinning 13C NMR spectra showed that CO2 binds chemically to IRMOF-74-III-CH2NH2 and -CH2NHMe to make carbamic species. Carbon dioxide
isotherms and breakthrough experiments show that IRMOF-74-III-CH2NH2 is especially efficient at taking up CO2 (3.2 mmol of CO2 per gram at 800 Torr) and, more
significantly, removing CO2 from wet nitrogen gas streams
with breakthrough time of 610 ± 10 s g–1 and
full preservation of the IRMOF structure.