Customizing Pore System in a Microporous Metal-Organic Framework for Efficient CH Separation from CO and CH.

Selective-adsorption separation is an energy-efficient technology for the capture of acetylene (CH) from carbon dioxide (CO) and ethylene (CH). However, it remains a critical challenge to effectively recognize CH among CO and CH, owing to their analogous molecule sizes and physical properties. Herein, we report a new microporous metal-organic framework () possessing a carefully tailored pore system containing moderate pore size and nitro-functionalized channel surface for efficient separation of CH from CO and CH. The activated (namely ) exhibits sufficient pore space to acquire excellent CH loading capacity (4.44 mmol g) under ambient conditions. In addition, it possesses dense nitro groups, acting as hydrogen bond acceptors, to selectively identify CH molecules rather than CO and CH. The breakthrough experiments demonstrate the good actual separation ability of for CH/CO and CH/CH mixtures. Furthermore, Grand Canonical Monte Carlo simulations indicate that the pore surface of the has a stronger affinity to preferentially bind CH over CO and CH via stronger C-H···O hydrogen bond interactions. This article provides some insights into customizing pore systems with desirable pore sizes and modifying groups in terms of MOF materials toward the capture of CH from CO and CH to promote the development of more MOF materials with excellent properties for gas adsorption and separation.