Design of polyhedral cage-engineered MOFs for efficient methane purification from natural gas

Scientists in China have developed two isostructural cage-type metal-organic frameworks (Co-TPT-TATBA and Ni-TPT-TATBA) by using tripodal carboxylic acid and pyridine ligands combined with cubane-type tetranuclear metal clusters, aiming at efficient methane purification from natural gas.

These MOFs feature a 3D pyr-topology framework with well-defined polyhedral cages of tunable sizes and pore surfaces functionalized with nitrogen-containing groups and sulfate anions, which synergistically enhance the adsorption affinity toward C₃H₈ and C₂H₆ over CH₄.

Benefiting from such structural advantages, both MOFs exhibit remarkably high adsorption capacities for C₃H₈ and C₂H₆ but extremely low CH₄ uptake at 298 K and 100 kPa. Dynamic breakthrough experiments further confirm that Co-TPT-TATBA and Ni-TPT-TATBA enable efficient separation of ternary C₃H₈/C₂H₆/CH₄ mixtures with high CH₄ productivity, while displaying excellent chemical stability over a wide pH range, showing great potential for industrial natural gas upgrading.

"Our cage-divided structural design effectively addresses the long-standing trade-off between adsorption capacity and selectivity in porous materials—achieving both high uptake and precise molecular sieving," says senior and co-corresponding author of the study, Yifan Gu. "This strategy opens new avenues for developing next-generation MOF adsorbents tailored for efficient natural gas upgrading."

The team also demonstrated the practical potential of the material by achieving a methane purity exceeding 99.9% in dynamic breakthrough tests, highlighting its suitability for industrial pressure swing adsorption (PSA) applications.

The complete findings of the study are published in the KeAi journal Green Chemical Engineering.

Contact author:

Ming-Shui Yao, University of Chinese Academy of Sciences, msyao@ipe.ac.cn;

Fengting Li, Tongji University, fengting@tongji.edu.cn;

Yifan Gu, Tongji University, 159219yifan_gu@tongji.edu.cn.

Funder:

National Key Research and Development Program of China (2022YFE0110500), the National Natural Science Foundation of China (22376161, 52373216, 22494633, and 22571304), the research fund of State Key Laboratory of Mycology and Engineering (MESO-25-E04), Fujian Provincial Natural Science Foundation of China (2024N0059), and the Fundamental Research Funds for the Central Universities in China

Conflict of interest:

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

See the article:

Qin, N. Q. et al., Design of polyhedral cage-engineered MOFs for efficient methane purification from natural gas, Green Chemical Engineering (2025). DOI: 10.1016/j.gce.2025.12.008.