Carbon capture in metal–organic frameworks—a comparative study

Metal–organic frameworks (MOFs) have been shown to be excellent materials for storage of carbon dioxide, implying that they could be useful for removal of carbon dioxide from flue gas stacks, however their performance in industrially relevant swing adsorption processes for carbon capture has not been studied. Here we show that the efficacy of MOFs for carbon capture depends dramatically on the process and that some MOFs can provide significant carbon capture under typical pressure and vacuum swing processes. In particular, MOFs that possess coordinatively unsaturated metal centers offer as much as 9 mmol g−1 swing capacity under certain conditions. The results herein clearly show that there is no single ideal compound for carbon capture applications and that different materials can perform better or worse depending on the specific process conditions. In addition to their capture performances, we have also investigated their selectivity to carbon dioxide over that of nitrogen and methane. The analysis provided clearly demonstrates that the performance of a given MOF cannot be determined without also considering the detailed industrial process in which the MOF is to be applied.