A Water-Stable Ultramicroporous Metal-Organic Framework with Aromatic Pore Walls for Coal-Mine Methane Capture

Selective separation of methane (CH₄) from nitrogen-rich coal-mine methane remains challenging owing to their similar physicochemical properties. Here we report a water-stable ultramicroporous metal-organic framework, Ni(Hbzza)₂, featuring densely packed aromatic pore walls that create a π-enriched confined environment for CH₄ adsorption. The 3-fold interpenetrated architecture generates narrow channels that may strengthen London dispersion interactions with CH₄, affording an uptake of 40 cm³ g^-1 at 298 K and a CH₄/N₂ selectivity of 5.6 (IAST). Breakthrough experiments demonstrate efficient dynamic separation under both dilute and humid conditions.