No abstract

The development of metal−organic framework (MOF) adsorbents with a potential molecule sieving effect for CO 2 capture and separation from flue gas is of critical importance for reducing the CO 2 emissions to the atmosphere yet challenging. Herein, a cagelike MOF with a suitable cage window size falling between CO 2 and N 2 and the cavity has been constructed to evaluate its CO 2 /N 2 separation performance. It is noteworthy that the introduction of coordinated dimethylamine (DMA) and N,N′-dimethylformamide (DMF) molecules not only significantly reduces the cage window size but also enhances the framework− CO 2 interaction via C−H•••O hydrogen bonds, as proven by molecular modeling, thus leading to an improved CO 2 separation performance. Moreover, transient breakthrough experiments corroborate the efficient CO 2 /N 2 separation, revealing that the introduction of DMA and DMF molecules plays a vital role in the separation of a CO 2 /N 2 gas mixture.

The separation of CO2 from the industrial post-combustion flue gas is of great importance to reduce the increasingly serious greenhouse effect, yet highly challenging due to the extremely high stability, low cost, and high separation performance requirements for adsorbents under the practical operating conditions. Herein, we report a robust squarate-cobalt metal–organic framework (MOF), FJUT-3, featuring an ultra-small 1D square channel decorated with −OH groups, for CO2/N2 separation. Remarkably, FJUT-3 not only has excellent stability under harsh chemical conditions but also presents low-cost property for scale-up synthesis. Moreover, FJUT-3 shows excellent CO2 separation performance under various humid and temperature conditions confirmed by the transient breakthrough experiments, thus enabling FJUT-3 with adequate potentials for industrial CO2 capture and removal. The distinct CO2 adsorption mechanism is well elucidated by theoretical calculations, in which the hierarchical C···OCO2 , C–O···CCO2 , and O–H···OCO2 interactions play a vital synergistic role in the selective CO2 adsorption process.