Biomimetic Liquid-Solid Interfaces for Selective and Moisture-Tolerant CO₂ Chemisorption.

Area of Science:

• Materials Science
• Chemical Engineering
• Nanotechnology

Background:

• Porous liquids (PLs) offer liquid-like flow and accessible porosity, surpassing solid adsorbents' mass-transfer limits.
• Enhancing chemical selectivity in PLs while maintaining fluidity and stability is a key challenge.

Purpose of the Study:

• To develop a biomimetic porous liquid with enhanced chemical selectivity for CO2 capture.
• To integrate metal-organic active sites within a fluidic system for selective adsorption.

Main Methods:

• Synthesized a Type III porous liquid by combining Zn2+-coordinated covalent organic framework (COF) scaffolds with a hydroxyl-functionalized ionic liquid (IL).
• Utilized in situ IR spectroscopy and atomistic simulations to characterize the CO2 adsorption mechanism and active site stability.

Main Results:

• Achieved high CO2 chemisorption uptake (106 cm3 g-1) and exceptional CO2/N2 selectivity (1273) under ambient conditions.
• Demonstrated selective CO2 admission and H2O exclusion via an IL-induced polarity gradient at the liquid-solid interface.
• Observed a reversible Zn-OH/Zn-OCO2H chemisorption cycle, confirming enzyme-like activity.

Conclusions:

• Established a molecular design principle for creating chemically specific, moisture-tolerant active sites in fluidic porous media.
• Opened new possibilities for selective chemisorption in liquid-phase materials for applications like carbon capture.