A Microporous Hydrogen Bonded Organic Framework for Highly Selective Separation of Carbon Dioxide over Acetylene

Abstract The separation of acetylene (C 2 H 2 ) from carbon dioxide (CO 2 ) is a very important but challenging task due to their similar molecular dimensions and physical properties. In terms of porous adsorbents for this separation, the CO 2 ‐selective porous materials are superior to the C 2 H 2 ‐selective ones because of the cost‐ and energy‐efficiency but have been rarely achieved. Herein we report our unexpected discovery of the first hydrogen bonded organic framework (HOF) constructed from a simple organic linker 2,4,6‐tri(1 H ‐pyrazol‐4‐yl)pyridine (PYTPZ) (termed as HOF‐FJU‐88) as the highly CO 2 ‐selective porous material. HOF‐FJU‐88 is a two‐dimensional HOFs with a pore pocket of about 7.6 Å. The activated HOF‐FJU‐88 takes up a high amount of CO 2 (59.6 cm 3 g −1 ) at ambient conditions with the record IAST selectivity of 1894. Its high performance for the CO 2 /C 2 H 2 separation has been further confirmed through breakthrough experiments, in situ diffuse reflectance infrared spectroscopy and molecular simulations.