Synthesis of [Mg2(DOBDC)(DMF)2]@polystyrene composite and its carbon dioxide adsorption

Abstract

[Mg2(DOBDC)] (Mg-MOF-74 or CPO-27-Mg) with open metal sites showed an exceptionally high CO2 uptake at low partial pressure and room temperature. The single-crystal structure of [Mg2(DOBDC)], however, has not been reported so far. In this work, we synthesized the crystalline product of [Mg2(DOBDC)(DMF)2] (1) and determined its single-crystal structure by synchrotron X-ray diffraction analysis. To improve the chemical stability and fabrication of the adsorbent, the composite of 1 and polystyrene (PS) was prepared by a simply solution-mixing method. Powder X-ray diffraction pattern of 1@PS revealed that the crystallinity of 1 is intact after incorporating PS. TGA of the composite revealed that 2.2 wt% of PS are incorporated to 1. CO2 sorption isotherms of activated 1@PS were measured in the temperature range between 283 and 303 K. The enthalpy of CO2 adsorption for activated 1@PS estimated by the virial equation at zero coverage is 43.9 kJmol-1, which is comparable to the reported value (47 kJmol-1) of activated 1. Interestingly, this composite showed high moisture stability after 90% humidity exposure for 1 day. © 2016 Elsevier Inc