High-throughput gas separation by flexible metal–organic frameworks with fast gating and thermal management capabilities
Shotaro Hiraide, Yuta Sakanaka, Hiroshi Kajiro, Shogo Kawaguchi, Minoru T. Miyahara, Hideki Tanaka
Abstract
Abstract Establishing new energy-saving systems for gas separation using porous materials is indispensable for ensuring a sustainable future. Herein, we show that ELM-11 ([Cu(BF 4 ) 2 (4,4′-bipyridine) 2 ] n ), a member of flexible metal–organic frameworks (MOFs), exhibits rapid responsiveness to a gas feed and an ‘intrinsic thermal management’ capability originating from a structural deformation upon gas adsorption (gate-opening). These two characteristics are suitable for developing a pressure vacuum swing adsorption (PVSA) system with rapid operations. A combined experimental and theoretical study reveals that ELM-11 enables the high-throughput separation of CO 2 from a CO 2 /CH 4 gas mixture through adiabatic operations, which are extreme conditions in rapid pressure vacuum swing adsorption. We also propose an operational solution to the ‘slipping-off’ problem, which is that the flexible MOFs cannot adsorb target molecules when the partial pressure of the target gas decreases below the gate-opening pressure. Furthermore, the superiority of our proposed system over conventional systems is demonstrated.