Chemical Research in Chinese Universities ›› 2025, Vol. 41 ›› Issue (4): 831-838.doi: 10.1007/s40242-025-5093-x

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Modulating the Host-guest Interactions in a Microporous Methyl-functionalized Pillar-layered Framework for Natural Gas Valorization

REN Qiao, FANG Yijie, ZHANG Yuke, DI Zhiping, DONG Longzhang YAN Yong   

  1. School of Chemistry, South China Normal University, Guangzhou 510006, P. R. China
  • Received:2025-05-13 Accepted:2025-06-28 Online:2025-08-01 Published:2025-07-24
  • Supported by:
    This work was supported by the National Natural Science Foundation of China (No. 22271103) and the Guangdong Provincial Basic and Applied Basic Research Foundation, China (No. 2024A1515012322).

Abstract: Methane (CH4), the primary constituent of natural gas (ca. 95%, volume fraction), serves as a pivotal clean energy resource. Effective CH4 purification remains a formidable challenge due to its co-existence with CO2 and higher hydrocarbons (C2H₆/C3H₈). Metal-organic frameworks (MOFs) have emerged as energy-efficient alternatives to cryogenic distillation by leveraging their tunable host-guest chemistry. Herein, we present a methyl-functionalized pillar-layered MOF, Ni-MPC-BPy, synthesized via hydrothermal assembly of the methyl-decorated pyrazole carboxylate ligand and bipyridine with Ni2+. This material shows high adsorption capacities of CO2/C3H8/C2H6 and preferential capture of CO2 and C2+ hydrocarbons over CH4[ideal adsorbed solution theory (IAST) selectivity:CO2/CH4=6.2; C3H₈/CH4=288.6; C2H₆/CH4=20], validated by dynamic breakthrough experiments achieving enrichment capacities of 29.6 and 79.9 mL/g of CH4 with 99.9% purity for mixtures of CO2/CH4 and C3H8/C2H6/CH4, respectively. Grand Canonical Monte Carlo simulations unveil that the engineered methyl motifs strengthen C2H₆/C3H₈ binding through cooperative C-H···O/C interactions and van der Waals contacts. This work establishes ligand functionalization as a potent strategy to tailor MOF pore chemistry for modulating the host-guest interactions, advancing the design of separation materials for sustainable natural gas valorization toward carbon-neutral energy systems.

Key words: Metal-organic framework, Microporous material, Host-guest interaction, Natural gas, Separation