Shape‐ and Size‐Dependent Kinetic Ethylene Sieving from a Ternary Mixture by a Trap‐and‐Flow Channel Crystal

Ethylene (C2H4) purification from multicomponent mixtures by physical adsorption presents a great challenge in the chemical industry. This work successfully uses the postsynthetic method of crystal transformation in boiling alkaline solution to synthesize a trap‐and‐flow channel crystal (namely NTU‐67), the flow channel of which provides an effective shape‐ and size‐dependent sieving path for linear molecules such as acetylene (C2H2) and carbon dioxide (CO2), while the adjacent channel possesses customized space for efficient molecular trapping. The three‐bladed array of the nanospace enables the crystal to afford a record productivity of C2H4 (121.5 mL g−1, >99.95%) from C2H2/CO2/C2H4 (1/9/90, v/v/v) mixtures in a single adsorption–desorption cycle under humid and dynamic conditions, even at a high temperature of 343 K and wide gas ratio. The molecular‐level insight and mechanism of the cooperative role of the trap‐and‐flow channel, found computationally and observed experimentally, demonstrates a new design philosophy toward extending the application boundaries of porous coordination polymers to further challenging tasks. A robust trap‐and‐flow channel crystal, conversed from boiling alkaline solution, is prepared, of which the flow channel provides an effective shape‐ and size‐dependent sieving path for linear acetylene (C2H2) and carbon dioxide (CO2), while the adjacent channel possesses customized space of efficient molecular trapping, yielding a record productivity of poly‐grade C2H4 from C2H2/CO2/C2H4 mixtures.