A Tailor-Made Interpenetrated MOF with Exceptional Carbon-Capture Performance from Flue Gas

Metal-organic frameworks (MOFs) have attracted significant attention as sorbents for low-energy separation of CO2 from flue gas. Herein, we report the use of an interpenetration approach to developing a fluorinated MOF with the appropriate pore system to enable the efficient capture of CO2 from flue gas at 298 K. The MOF, dptz-CuTiF6, exhibits excellent volumetric and gravimetric CO2 uptakes at 10% CO2 and 298 K, which are superior to those of the reference aqueous amine technique, with significantly lower energy input for regeneration (38 kJ mol−1 versus 105 kJ mol−1). In cyclic breakthrough experiments, dptz-CuTiF6 achieves complete CO2 desorption at 298 K under inert gas purging. Single-crystal X-ray diffraction studies demonstrate that the exceptional CO2 adsorption capacity, moderate CO2 heat of adsorption, and high CO2-N2 selectivity are due to the optimal packing of the CO2 molecules within the MOF as well as the favorable thermodynamics and kinetics from cooperative host-guest interactions. Increasing amounts of atmospheric CO2 by the combustion of fossil fuels prompt a notable temperature change along with other environmental issues. In parallel with the development of renewable energy technologies, new processes and materials for effective and energy-efficient CO2 capture are urgently coveted. By applying the interpenetration strategy, a newly developed microporous fluorinated metal-organic framework, dptz-CuTiF6, achieves superior CO2 uptake capacity and significantly lower regeneration energy than the reference aqueous amine technology. The exceptional CO2 adsorption performance can be rationalized by the optimal CO2 packing within the framework and the cooperative host-guest interactions. The MOF dptz-CuTiF6 offers excellent volumetric and gravimetric CO2 uptake at 10% CO2 and 298 K, superior to the reference, aqueous amine, with a significantly lower energy input for regeneration. The fluorinated MOF can be regarded as a potential candidate for energy-efficient CO2 capture from flue gas. Single-crystal X-ray diffraction studies provided valuable molecular insights on the excellent CO2 adsorption performance of the MOF adsorbent.