Metal−Organic Frameworks with Exceptionally High Capacity for Storage of Carbon Dioxide at Room Temperature

Abstract

Metal−organic frameworks (MOFs) show high CO₂ storage capacity at room temperature. Gravimetric CO₂ isotherms for MOF-2, MOF-505, Cu₃(BTC)₂, MOF-74, IRMOFs-11, -3, -6, and -1, and MOF-177 are reported up to 42 bar. Type I isotherms are found in all cases except for MOFs based on Zn₄O(O₂C)₆ clusters, which reveal a sigmoidal isotherm (having a step). The various pressures of the isotherm steps correlate with increasing pore size, which indicates potential for gas separations. The amine functionality of the IRMOF-3 pore shows evidence of relatively increased affinity for CO₂. Capacities qualitatively scale with surface area and range from 3.2 mmol/g for MOF-2 to 33.5 mmol/g (320 cm³(STP)/cm³, 147 wt %) for MOF-177, the highest CO₂ capacity of any porous material reported.