Viable Metal–Organic Framework Adsorbents for Thermodynamics-Driven Methane/Hydrogen Separation

Abstract Hydrogen is a clean energy carrier that supports low-carbon mobility and power generation and is widely used in oil refining and methanol production. Efficient separation of methane (CH4) from hydrogen (H2) is critical in the hydrogen supply chain, particularly for H2 purification after steam methane reforming and H2 recovery from natural gas pipelines. In this work, atomistic simulations were employed to systematically evaluate a diverse set of existing metal–organic frameworks (MOFs) for physisorption-based CH4/H2 separation under realistic pressure swing adsorption (PSA) conditions. The selected MOFs combine favorable chemical and geometrical features with practical advantages including synthetic feasibility, stability, environmental sustainability, and scalability. Force field Monte Carlo simulations were deployed to predict single-component and mixture adsorption isotherms of CH4 and H2, as well as their adsorption enthalpies at zero coverage, with the approach validated against experimental adsorption and breakthrough data for selected materials. Several MOFs were predicted to outperform the commercial adsorbent Zeolite 13X, exhibiting superior separation performance in terms of CH4/H2 selectivity and CH4 working capacity. Structure–property analysis revealed key relationships between pore architecture, chemical functionality, and separation performance. Furthermore, molecular dynamics simulations of CH4 diffusion in the MOF pores confirmed the kinetic suitability of top-performing materials for PSA operation. Overall, this study identifies a set of viable MOFs as promising candidates for efficient CH4/H2 separation and provides molecular-level insights to guide the development of hydrogen purification technologies.