Nanoarchitectonics of Methyl and Aldehyde Group-Decorated SOD-Type Metal-Azolate Framework for SF6 Capture and Recovery

Sulfur hexafluoride (SF6) is widely used as an insulating gas, being an etchant and contrast agent in the electrical, semiconductor, and medical industries. However, due to its long lifetime and high global warming potential in the atmosphere, SF6 must be carefully handled to prevent leakage during production and usage. Herein, we report a sod-net metal-azolate framework (MAF) named MAF-stu-111, which decorates methyl and aldehyde groups in the porous windows, showing high adsorption affinity for SF6 at low pressure. Stability tests, gas adsorption, and breakthrough experiments demonstrated that MAF-stu-111 possesses excellent water and chemical stability, fully reversible SF6 uptake, high SF6/N2 separation selectivity (10:90, 285.2), good reusability, and high SF6 recovery purity (99.03%). Theoretical calculations revealed that hydrogen atoms of methyl and aldehyde groups can form multiple hydrogen bonds with SF6 molecules, which ensure that SF6 molecules are firmly held within the MAF-stu-111 framework, playing a key role in the selective separation of SF6/N2.