Trace Capture Hexafluoropropylene From Octafluoropropane via Complete Molecular Sieving Mechanism in a Highly Robust Metal-Organic Framework.

Deep removal of trace hexafluoropropylene (C3F6) impurity from octafluoropropane (C3F8) using porous adsorbents is highly promising, but the field still suffers from the lack of benchmark adsorbents capable of overcoming the inherent trade-off between adsorption capacity and uptake ratio. Herein, we report a highly robust metal-organic framework, Ni-pca-pyz, which features an electrostatic-potential complementary surface and molecular-sieving channel tailored for C3F6, realizes the optimal accommodation of C3F6 and complete exclusion of C3F8. Ni-pca-pyz exhibits a record-high C3F6/C3F8 uptake ratio (137.6), coupled with exceptional C3F6 adsorption capacity (55.02 cm3 g-1) at 298 K and 1.0 bar. Kinetic analysis further confirms negligible adsorption of C3F8 (0.36 cm3 g-1) in Ni-pca-pyz, and effective diffusion coefficient for C3F6 is 9.29 × 10-5 s-1 at 298 K. Molecular simulations and in situ Fourier transform infrared spectroscopy (FTIR) elucidate the synergetic effect of pore confinement, and surface electrostatic complementarity confers high recognition of C3F6 through multiple hydrogen bonding interactions. The column breakthrough experiments validate the efficient removal of trace C3F6 from C3F8, affording an excellent C3F8 productivity of 2.06 × 103 L kg-1 (purity exceeding 99.999%). With its outstanding stability, recyclability, and low-cost precursors, Ni-pca-pyz provides an ideal platform for industrial perfluorinated electronic specialty gases (ESGs) purification.