Hierarchical porous metal organic framework aerogel for highly efficient CO2 adsorption

Sustainable low-carbon economy has attracted global attention, and the development of advanced CO2 capture technology has become an important undertaking. Metal organic frameworks (MOFs) featured with high specific surface area and large porosity have held the promise for CO2 adsorption, but the micron scale make them difficult to handle, leading to easily be blown away, pipeline blockage, and the decline of adsorption capacity. Here, we demonstrate a novel strategy to develop a nanoporous HKUST-1 aerogel with hierarchical pore structure by combining HKUST-1 and aramid nanofiber for promoting CO2 adsorption. The resultant HKUST-1 aerogel has a low density of 5.86 mg/cm3, high specific surface area of 636.62 m2g−1, and hierarchical porosity of 99.33 %. The meso-/macropores of HKUST-1 aerogel can act as gas transfer channels to facilitate the transport CO2 into the HKUST-1, and the micropores of HKUST-1 provide active sites for CO2 adsorption. Benefitting from the synergistic effect of the hierarchical pore structure, the HKUST-1 aerogel demonstrates high CO2 adsorption capacity of 7.29 mmol/g, and high adsorption selectivity of 39 for CO2/N2 and 42 for CO2/O2. This novel design may provide a reliable theoretical and experimental basis for the development of MOF aerogel as CO2 adsorbent candidate for environmental purification.