(724b) First Principles Study of CO2 Adsorption in MOF-74

Carbon dioxide capture and sequestration is one important route to tackle the adverse environmental effects associated with the extensive human greenhouse gas emissions. Metal-organic framework (MOF) materials, a new class of nanoporous crystalline solids, are promising candidates as adsorbent materials for CO2 capture. The growing interest in MOFs as adsorbents is largely due to their high internal surface area, large pore volume, and the possibility to tailor the pores with a variety of functionalities. In this talk, we will present our first principles study of CO2 adsorption in a group of MOF materials called MOF-74. These materials consist of one-dimensional channels with a high concentration of open metal sites and have been identified as one of the most promising MOFs for CO2 capture. Our study shows that CO2 adsorption is largely due to the strong interaction between CO2 molecules with the open metals sites of MOF-74. The binding energies of CO2 calculated for Mg-MOF-74, Ni-MOF-74, and Co-MOF-74 are in the same order as obtained from experiments. By examining the detailed electronic interactions using natural bond orbital analysis, we are able to explain the order of heat of adsorption among this group of MOF-74 materials and the specific CO2 adsorption configurations observed in experiments.