Regulating Layer Organization to Engage Amino Groups for Efficient CH 4 /N 2 Separation in a Pillar-Layer Metal–Organic Framework

Selective capture of methane (CH 4 ) from nitrogen (N 2 ) in coal-bed methane using a physisorbent represents a promising strategy due to its potential for low energy consumption and cost-efficiency. Microporous metal–organic frameworks (MOFs) offer considerable potential for this application through tunable pore design, yet they face unresolved challenges including stability, low-cost synthesis, and adsorption durability. Herein, we demonstrate the effective capture of CH 4 from N 2 via a microporous zinc-aminotriazolate-acetate (Zn-Atz-Ac) framework. Employing zinc, acetate, and 3-amino-1,2,4-triazole, Zn-Atz-Ac is synthesized through an atom-economical route. Owing to a tortuous pore structure with numerous pockets containing abundant accessible nitrogen and oxygen sites, this material exhibits a CH 4 uptake of 25.18 cm 3 g –1 (298 K and 100 kPa) with a high CH 4 /N 2 selectivity of 7.8. Notably, Zn-Atz-Ac maintains robust structural integrity and adsorption performance over five consecutive adsorption–desorption cycles. In contrast, an oxalate-pillared analogue Zn-Atz-OX exhibits a much lower CH 4 uptake of 18.2 cm 3 g –1 and a lower selectivity of 3.3 due to a less functionalized pore environment. Theoretical calculations reveal that the amino-rich pore environment in Zn-Atz-Ac contributes to its stronger preference for CH 4 . Finally, breakthrough experiments confirm the effectiveness of Zn-Atz-Ac for CH 4 /N 2 separation under dynamic conditions, demonstrating practical utility.