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

Abstract

ABSTRACT Deep removal of trace hexafluoropropylene (C 3 F 6 ) impurity from octafluoropropane (C 3 F 8 ) 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 C 3 F 6 , realizes the optimal accommodation of C 3 F 6 and complete exclusion of C 3 F 8 . Ni‐pca‐pyz exhibits a record‐high C 3 F 6 /C 3 F 8 uptake ratio (137.6), coupled with exceptional C 3 F 6 adsorption capacity (55.02 cm 3 g −1 ) at 298 K and 1.0 bar. Kinetic analysis further confirms negligible adsorption of C 3 F 8 (0.36 cm 3 g −1 ) in Ni‐pca‐pyz, and effective diffusion coefficient for C 3 F 6 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 C 3 F 6 through multiple hydrogen bonding interactions. The column breakthrough experiments validate the efficient removal of trace C 3 F 6 from C 3 F 8 , affording an excellent C 3 F 8 productivity of 2.06 × 10 3 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.