Immobilization of H <sub>2</sub> O in Diffusion Channel of Metal–Organic Frameworks for Long‐Term CO <sub>2</sub> Capture from Humid Flue Gas
Yang Chen, Kaihua Wang, Jing‐Hong Li, Jing‐Hong Li, Yi Wang, Rui‐Biao Lin, Xiao‐Ming Chen, Jinping Li, Jinping Li, Libo Li
Abstract
Abstract Utilizing physisorption for CO 2 capture in humid flue gas presents challenges, with H 2 O molecules either damaging the adsorbent or competing with CO 2 for adsorption, compromising long‐term stability. Herein, a counter‐intuitive strategy is proposed to address this issue by immobilizing H 2 O into metal–organic framework (TYUT‐ATZ, TYUT = Taiyuan University of Technology, ATZ = 3‐amino‐1,2,4‐triazole) as binding sites for CO 2 capture from humid airflow. Through tailoring the ‐NH 2 group numbers and pore sizes creates ingenious H 2 O sites, preserving CO 2 adsorption space and enhancing CO 2 adsorption interactions in 1D channels. The well‐constructed TYUT‐ATZ‐β demonstrates a high CO 2 adsorption capacity (62.7 cm 3 cm −3 ) at 0.15 bar and outstanding CO 2 /N 2 (15/85) selectivity (2031) at 298 K, while also exhibits the highest CO 2 /H 2 O uptake ratio in humid flue gas due to its excellent water stability and unique H 2 O site. Consequently, it shows top‐performing CO 2 enrichment ability with easy regeneration in long‐term separation experiments (over 100 cycles) under high‐humidity (75% RH). Gas adsorption isotherms, single‐crystal analysis, selectivity calculations, and contrastive breakthrough experiments comprehensively validate this artful H 2 O immobilization strategy in MOFs for efficient CO 2 capture in humid flue gas, satisfying the application requirements of high selectivity, rapid regeneration, and long‐term stability.