Authors: Junning Kou, Dongxu Cui, Jianzhu Jiang, Wenliang Li, Guogang Shan, Hao Wang, Xinlong Wang, Zhongmin Su, Chunyi Sun
Published: 2025-03-12
Source: Full article
AbstractConstructing a metal‐free adsorbent for one‐step separation of C2H4 from mixture gas of C2, is of great significance and challenging. Here, a porous aromatic cage (PAC‐1) based on aldehyde‐amine condensation is reported with diamond‐like interconnected aromatic cavity‐channel pores for one‐step purification of ethylene. PAC‐1 exhibits superior C2H2 (52.6 cm3 g−1) and C2H6 (46.7 cm3 g−1) uptakes as well as impressive C2H2/C2H4 selectivity (1.5) and C2H6/C2H4 selectivity (1.4), remaining at the forefront of the advanced C2H4‐selective adsorbents of porous non‐metallic materials. The C2H4 adsorption enthalpy (Qst) of PAC‐1 is of 23.6 kJ mol−1, which requires less energy to regenerate than conventional MOF materials. Breakthrough experiments demonstrate that PAC‐1 can reduce the penetration rate of C2H6 or C2H2 through the adsorbent, and present quite valuable one‐step separation of C2H4 from C2H2/C2H6/C2H4 mixture gas. Molecular simulations and DFT studies have shown that oxygen sites and C─H sites in the channels are more favorable for C2H2 anchor with interaction energy over C2H4 by 1.48 kcal mol−1, and the C─H…π interaction point in cage cavity is preferred to C2H6 with the interaction energy over C2H4 by 1.16 kcal mol−1, which in turn results in the separation of C2H4 from C2H2 and C2H6.