Fine-tuning the pore environment of ultramicroporous three-dimensional covalent organic frameworks for efficient one-step ethylene purification.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 38589420.
- Also identified by DOI 10.1038/s41467-024-47377-3 and PMC identifier 11001888.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The construction of functional three-dimensional covalent organic frameworks (3D COFs) for gas separation, specifically for the efficient removal of ethane (C<sub>2</sub>H<sub>6</sub>) from ethylene (C<sub>2</sub>H<sub>4</sub>), 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 C<sub>2</sub>H<sub>4</sub> 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 C<sub>2</sub>H<sub>6</sub> adsorption capacity (110.4 cm<sup>3</sup> g<sup>-1</sup> at 293 K and 1 bar) and good C<sub>2</sub>H<sub>6</sub>/C<sub>2</sub>H<sub>4</sub> selectivity (1.8), due to the formation of additional C-H···N interactions between pyridine groups and C<sub>2</sub>H<sub>6</sub>. 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 C<sub>2</sub>H<sub>4</sub> directly from a C<sub>2</sub>H<sub>6</sub>/C<sub>2</sub>H<sub>4</sub> mixture. This study provides important guidance for the rational design of 3D COFs for efficient gas separation.