A series of mixed-ligand [1,4-benzenedicarboxylic acid (BDC)/2-amino-1,4-benzenedicarboxylic acid (ABDC)] UiO-66 metal-organic frameworks (MOFs) synthesized through two different methods (low (LT) and high temperature (HT)) have been investigated for their carbon dioxide adsorption properties from 0 to 1 bar to clarify the role of amino loading on carbon dioxide uptake. Volumetric CO2 isotherms show that the CO2 capacity (normalized to the Langmuir surface area) increases with a degree of functionalization of about 46 %; for similar NH2 contents, the same values are found for both synthetic procedures. Microcalorimetric isotherms reveal that aminofunctionalized materials have a larger differential heat of adsorption (qdiff) towards CO2; reaching 27(25) and 20(22) kJmol-1 on HT(LT)-UiO-66-NH2 and UiO-66, respectively, at the lowest equilibrium pressures used in this study. All experimental results are supported by values obtained through quantum mechanical calculations.
Bibliographical notePublisher Copyright:
© 2014 Wiley-VCH Verlag GmbH & Co. KGaA.
- Ab initio calculations
- Carbon dioxide capture
- IR spectroscopy
- Metal-organic frameworks