Exquisitely Constructing a Robust MOF with Dual Pore Sizes for Efficient CO(2) Capture

Developing metal–organic framework (MOF) adsorbents with excellent performance and robust stability is of critical importance to reduce CO(2) emissions yet challenging. Herein, a robust ultra-microporous MOF, Cu(bpfb)(bdc), with mixed ligands of N, N′-(1,4-phenylene)diisonicotinamide (bpfb), and 1,4-dicarboxybenzene (bdc) was delicately constructed. Structurally, this material possesses double-interpenetrated frameworks formed by two staggered, independent frameworks, resulting in two types of narrow ultra-micropores of 3.4 × 5.0 and 4.2 × 12.8 Å(2), respectively. The above structural properties make its highly selective separation at 273~298 K with a CO(2) capacity of 71.0~86.2 mg/g. Its adsorption heat over CO(2) and IAST selectivity were calculated to be 27 kJ/mol and 52.2, respectively. Remarkably, cyclic breakthrough experiments corroborate its impressive performance in CO(2)/N(2) separation in not only dry but also 75% RH humid conditions. Molecular simulation reveals that C-H···O(CO2) in the pores plays a pivotal role in the high selectivity of CO(2) adsorption. These results point out the huge potential application of this material for CO(2)/N(2) separation.