Optimizing the pore space of a robust nickel–organic framework for efficient C2H2/C2H4 separation

Abstract

The separation of acetylene (C₂H₂) from ethylene (C₂H₄) is an important but challenging process in industry because of their similar physical properties and kinetic molecular sizes. Here, we presented a robust nickel–organic framework (UPC-22) with intrinsic hydrogen bonds and one-dimensional functionalized channels, offering efficient purification of C₂H₄. UPC-22 exhibits excellent chemical stability at various pH values from 1 to 11 and a high C₂H₂/C₂H₄ selectivity of 4.8 at 273 K. Actual breakthrough experiments further demonstrate that UPC-22 is a promising potential adsorbent for C₂H₂/C₂H₄ separation with a C₂H₄ productivity of 1.07 mmol g⁻¹. Grand canonical Monte Carlo simulation and density functional theory indicate that the unsaturated Ni^II sites and uncoordinated carboxylate groups with an additional contribution from π⋯π packing between aromatic rings provide stronger multipoint interactions with C₂H₂ over C₂H₄. This study offers practical guidance to fabricate durable materials for C₂H₂/C₂H₄ separation in real industrial scenarios.