In comparison with the fast development of binary mixture separations, ternary mixture separations are significantly more difficult and have rarely been realized by a single material. Herein, a new strategy of tuning the gate‐opening pressure of flexible MOFs is developed to tackle such a challenge. As demonstrated by a flexible framework NTU‐65, the gate‐opening pressure of ethylene (C2H4), acetylene (C2H2), and carbon dioxide (CO2) can be regulated by temperature. Therefore, efficient sieving separation of this ternary mixture was realized. Under optimized temperature, NTU‐65 adsorbed a large amount of C2H2 and CO2 through gate‐opening and only negligible amount of C2H4. Breakthrough experiments demonstrated that this material can simultaneously capture C2H2 and CO2, yielding polymer‐grade (>99.99 %) C2H4 from single breakthrough separation.

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.

Energy-efficient separation of propylene (C 3 H 6 )/ propane (C 3 H 8 ) is in high demand for the chemical industry. However, this process is challenging due to the imperceptible difference in molecular sizes of these gases. Here, we report a continuous water nanotube dedicatedly confined in a Cu 10 O 13based metal−organic framework (MOF) that can exclusively adsorb C 3 H 6 over C 3 H 8 with a record-high selectivity of 1570 (at 1 bar and 298 K) among all the porous materials. Such a high selectivity originates from a new mechanism of initial expansion and subsequent contraction of confined water nanotubes (∼4.5 Å) caused by C 3 H 6 adsorption rather than C 3 H 8 . Such unique response was further confirmed by breakthrough measurements, in which one adsorption/desorption cycle yields each component of the binary mixture high purity (C 3 H 6 : 98.8%; C 3 H 8 : >99.5%) and good C 3 H 6 productivity (1.6 mL mL −1 ). Additionally, benefiting from the high robustness of the framework, the water nanotubes can be facilely recovered by soaking the MOF in water, ensuring long-term use. The molecular insight here demonstrates that the confining strategy opens a new route for expanding the function of MOFs, particularly for the sole recognition from challenging mixtures.

High-quality pure acetylene (C2H2) is a kind of crucial starting material for various value-added products. However, selective capture of C2H2 from the main impurity of CO2 via porous absorbents is a great challenge, as they possess extremely similar kinetic diameters and boiling points, as well as the explosive and reactive properties of C2H2. Herein, we report a porous coordination polymer (PCP), (NTU-55), which assembled from the coordination between a Cu dimer and a newly designed ligand with a nonmetal selenium (Se) site. Static single-component adsorption and dynamic breakthrough experiments reveal that desolvated NTU-55 can completely adsorb C2H2 from the C2H2/CO2 mixture (1/4, v/v) at 298 K, along with higher C2H2 capacity and much lower binding energy. The origin of this separation, as comprehensively revealed by density functional theory (DFT) calculations, is derived from the interaction discriminatory of C2H2 and CO2 toward accessible Se and Cu adsorption sites. To the best of our knowledge, this is the first time to find the positive effect of nonmetal Se sites for selective C2H2 capture.

Safely and highly selective acetylene (C 2 H 2 ) capture is a great challenge, because of its highly explosive nature, as well as its nearly similar molecule size and boiling point toward the main impurity of carbon dioxide (CO 2 ). Adsorption separation has shown a promising future. Herein, a new nanoporous coordination polymer (PCP) adsorbent with fixed and free Cu ions (termed NTU-66-Cu) was prepared through post-synthetic approach via cation exchanging from the pristine NTU-66, an anionic framework with new 3, 4, 6-c topology and two kinds of cages. The NTU-66-Cu shows significantly improved C 2 H 2 /CO 2 selectivity from 6 to 32 (v/v: 1/1) or 4 to 42 (v/v: 1/4) at low pressure under 298 K, along with enhanced C 2 H 2 capacity (from 89.22 to 111.53 cm 3 •g −1 ). More importantly, this observation was further validated by density functional theory (DFT) calculations and breakthrough experiments under continuous and dynamic conditions. Further, the excellent chemical stability enables this adsorbent to achieve recycle C 2 H 2 /CO 2 separation without loss of C 2 H 2 capacity.