Quasi-Discrete Channels of Porous Coordination Polymers for Selective Multiscenario CO₂ Recognition

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Selective carbon dioxide (CO2) separation from industrial gas streams is challenging due to the presence of similar gas molecules.
• Existing materials often lack the required selectivity, efficiency, or stability for practical CO2 capture applications.

Purpose of the Study:

• To develop a novel material for highly selective CO2 recognition and separation from diverse gas mixtures.
• To investigate the mechanism behind the selective CO2 binding and transport within the material.

Main Methods:

• Synthesis and characterization of an interdigitated coordination polymer (CID-PNA) with quasi-discrete channels.
• Gas adsorption/desorption isotherms, breakthrough experiments, in situ crystallography, spectroscopy, and theoretical calculations were employed.
• Performance evaluation against benchmark materials like CALF-20, ALF, and Zeolite-13X.

Main Results:

• CID-PNA exhibited excellent selectivity for CO2 over C2H2, CH4, and N2 (5.1, 14.8, and 117.7, respectively).
• The material demonstrated rapid adsorption-desorption kinetics, moderate CO2 adsorption enthalpy (33.2 kJ mol-1), and high CO2/H2O uptake ratio (3.24).
• One-step purification of high-purity C2H2, CH4, and N2 from CO2-containing mixtures was achieved, even under challenging wet-hot flue gas conditions.

Conclusions:

• The CID-PNA material effectively separates CO2 from various gas mixtures due to cooperative C═O···H and π···π interactions within its confined aromatic pockets.
• The quasi-discrete aromatic channels provide a versatile design for efficient CO2 capture, transport, and energy-saving regeneration.
• This study presents a promising general strategy for developing advanced materials for selective CO2 separation in industrial settings.