One‐Step C₂H₄ Purification from Ternary C₂H₆/C₂H₄/C₂H₂ Mixtures by a Robust Metal–Organic Framework with Customized Pore Environment

One‐step C 2 H 4 purification from ternary C 2 H 6 /C 2 H 4 /C 2 H 2 mixtures by a single adsorbent is of great industrial significance, but few adsorbents achieve this separation. Herein, we report a robust metal–organic framework (MOF) that possesses methyl‐decorated nonpolar pores and shows one‐step C 2 H 4 purification (purity >99.9 %) from binary C 2 H 6 /C 2 H 4 mixtures and ternary C 2 H 6 /C 2 H 4 /C 2 H 2 mixtures. The methyl groups in pores provide a suitable pore environment to simultaneously enhance the adsorption capacity for C 2 H 2 and C 2 H 6 compared to C 2 H 4 . Simulations revealed the multiple interactions between C 2 H 6 or C 2 H 2 molecules and the pore wall, while the interactions with C 2 H 4 molecules are weak and also unfavorable due to the repulsion from methyl groups in pores. The MOF displays high C 2 H 6 and C 2 H 2 uptakes and benchmark C 2 H 6 /C 2 H 4 selectivity (2.2), surpassing all of the reported MOFs for one‐step C 2 H 4 purification from ternary C 2 H 6 /C 2 H 4 /C 2 H 2 mixtures.