Metal-Organic Gel Material Based on UiO-66-NH2 Nanoparticles for Improved Adsorption and Conversion of Carbon Dioxide.

Metal-organic frameworks (MOFs) including the UiO-66 series show potential application in the adsorption and conversion of CO2 . Herein, we report the first tetravalent metal-based metal-organic gels constructed from Zr(IV) and 2-aminoterephthalic acid (H2 BDC-NH2 ). The ZrBDC-NH2 gel materials are based on UiO-66-NH2 nanoparticles and were easily prepared under mild conditions (80 °C for 4.5 h). The ZrBDC-NH2 -1:1-0.2 gel material has a high surface area (up to 1040 m(2)  g(-1) ) and showed outstanding performance in CO2 adsorption (by using the dried material) and conversion (by using the wet gel) arising from the combined advantages of the gel and the UiO-66-NH2 MOF. The ZrBDC-NH2 -1:1-0.2 dried material showed 38 % higher capture capacity for CO2 at 298 K than microcrystalline UiO-66-NH2 . It showed high ideal adsorbed solution theory selectivity (71.6 at 298 K) for a CO2 /N2 gas mixture (molar ratio 15:85). Furthermore, the ZrBDC-NH2 -1:1-0.2 gel showed activity as a heterogeneous catalyst in the chemical fixation of CO2 and an excellent catalytic performance was achieved for the cycloaddition of atmospheric pressure of CO2 to epoxides at 373 K. In addition, the gel catalyst could be reused over multiple cycles with no considerable loss of catalytic activity.