The local electric field favours more than exposed nitrogen atoms on CO2 capture: a case study on the rht-type MOF platform

Abstract

Two rht-type metal–organic frameworks (MOFs) based upon the tetrazolate moiety and pyrazolate moiety, respectively, have been investigated for carbon dioxide (CO₂) adsorption and selective adsorption of CO₂ over CH₄, which shows that the rht-MOF featuring the pyrazolate moiety demonstrates superior performances compared to the rht-MOF based on the tetrazolate moiety. In spite of more exposed nitrogen atoms in the tetrazolate-based rht-MOF, the counter-intuitive observations of CO₂ capture in the two rht-MOFs were interpreted by computational studies, which reveal that the local electric field favours more than the richness of exposed nitrogen atoms for the interactions with CO₂ molecules.