A Microporous Titanium Metal-Organic Framework with Double Nanotraps for Record CH₄/N₂ Separation

Reining in global warming has been an international priority, and mitigation targets post-2020 set at the 21st Conference of the Parties (COP21) urge that measures be taken. To significantly increase the utilization efficiency of unconventional natural gas and curtail its effect on global warming, we herein report a titanium metal-organic framework adsorbent with double nanotraps featuring superior CH₄ uptake (1.37 mmol/g) and a high CH₄/N₂ selectivity (21.6-12.0) at 298 K up to 1 bar. The strong CH₄ confinement of the nanotraps is observed and unveiled using neutron powder diffraction studies and density functional theory calculations. Breakthrough experiments on equimolar CH₄/N₂ mixtures confirm that CH₄ could be efficiently enriched with a record productivity (13.1 L/kg) through a single separation operation, demonstrating the promising application potential of this microporous material for unconventional natural gas enrichment in industry.