The construction of functional three-dimensional covalent organic frameworks (3D COFs) for gas separation, specifically for the efficient removal of ethane (C₂H₆) from ethylene (C₂H₄), is significant but challenging due to their similar physicochemical properties. In this study, we demonstrate fine-tuning the pore environment of ultramicroporous 3D COFs to achieve efficient one-step C₂H₄ purification. By choosing our previously reported 3D-TPB-COF-H as a reference material, we rationally design and synthesize an isostructural 3D COF (3D-TPP-COF) containing pyridine units. Impressively, compared with 3D-TPB-COF-H, 3D-TPP-COF exhibits both high C₂H₆ adsorption capacity (110.4 cm³ g⁻¹ at 293 K and 1 bar) and good C₂H₆/C₂H₄ selectivity (1.8), due to the formation of additional C-H···N interactions between pyridine groups and C₂H₆. To our knowledge, this performance surpasses all other reported COFs and is even comparable to some benchmark porous materials. In addition, dynamic breakthrough experiments reveal that 3D-TPP-COF can be used as a robust absorbent to produce high-purity C₂H₄ directly from a C₂H₆/C₂H₄ mixture. This study provides important guidance for the rational design of 3D COFs for efficient gas separation.

用于气体分离的功能性三维共价有机框架（3D COF）的构建，特别是用于从乙烯（C ₂ H ₄ ）中有效去除乙烷（C ₂ H ₆ ），具有重要意义，但由于其相似的物理化学性质而具有挑战性。在这项研究中，我们展示了对超微孔3D COF 的孔隙环境进行微调，以实现高效的一步式C ₂ H ₄纯化。通过选择我们之前报道的3D-TPB-COF-H作为参考材料，我们合理设计并合成了含有吡啶单元的同构3D COF（3D-TPP-COF）。令人印象深刻的是，与3D-TPB-COF-H相比，3D-TPP-COF同时表现出高C ₂ H ₆吸附容量（在293 K和1 bar下为110.4 cm ³ g ^-1 ）和良好的C ₂ H ₆ /C ₂ H ₄选择性(1.8)，由于吡啶基团和C ₂ H ₆之间形成额外的CH·N相互作用。据我们所知，这种性能超越了所有其他报道的 COF，甚至可以与一些基准多孔材料相媲美。此外，动态突破性实验表明，3D-TPP-COF可用作强大的吸收剂，直接从C ₂ H ₆ /C ₂ H ₄混合物生产高纯度C ₂ H ₄ 。该研究为合理设计3D COF以实现高效气体分离提供了重要指导。