One‐Dimensional Channel with Side Pockets for Rapid Diffusion and Efficient C ₂ H ₂ Purification

Abstract Efficiently separating acetylene (C 2 H 2 ) from carbon dioxide (CO 2 ) has been a long‐standing challenge due to their similar molecular dimensions and physical properties. Herein, we report a series of isostructural pillar‐layered metal–organic frameworks (MOFs), named JNU‐13, JNU‐13‐CH 3 , and JNU‐13‐(CH 3 ) 2 . These MOFs feature one‐dimensional (1D) channels integrated with orthogonally arrayed side pockets, enabling dense packing of C 2 H 2 molecules while maintaining rapid diffusion pathways. Specifically, JNU‐13‐CH 3 achieves a high C 2 H 2 packing density of 360 g L −1 , a low adsorption enthalpy of 31.61 kJ mol −1 , and adsorption/desorption coefficients one to two orders of magnitude higher than other benchmark MOFs. Breakthrough experiments reveal a high C 2 H 2 capture capacity of 3.46 mmol g −1 from an equimolar C 2 H 2 /CO 2 mixture at 298 K and 1 bar, even under humid conditions. Moreover, we demonstrate the scale‐up synthesis of JNU‐13‐CH 3 and gas‐cylinder collection of high‐purity C 2 H 2 , achieving >99.9% from a C 2 H 2 /CO 2 (95/5) mixture and >99.7% from a C 2 H 2 /CO 2 /CH 4 (95/2.5/2.5) mixture. Overall, this study highlights the effectiveness of orthogonal‐arrayed side pockets for balancing dense packing and mass transport, offering a promising strategy for energy‐efficient C 2 H 2 purification.