Hydrophobic Nanoconfinement Enhances CO₂ Conversion to H₂CO₃

Area of Science:

• Environmental Chemistry
• Physical Chemistry
• Materials Science

Background:

• The conversion of carbon dioxide (CO2) to carbonic acid (H2CO3) is crucial for environmental and industrial applications.
• Previous studies have focused on bulk water, leaving the behavior in nanoconfined environments poorly understood.

Purpose of the Study:

• To investigate the differences in CO2 to H2CO3 conversion between bulk and nanoconfined aqueous systems.
• To elucidate the impact of nanoconfinement on the reaction's thermodynamics and kinetics.

Main Methods:

• Utilized ReaxFF metadynamics molecular simulations.
• Analyzed free energy changes, energy barriers, and intermediate formation.

Main Results:

• Nanoconfinement dramatically alters the free energy landscape of CO2 conversion.
• The reaction energy barrier is reduced, and the reaction shifts from endothermic in bulk water to exothermic in nanoconfined water.
• Charged intermediates are observed more frequently under nanoconfinement, with enhanced solvation and proton transfer.

Conclusions:

• Nanoconfinement significantly enhances both the thermodynamics and kinetics of CO2 to H2CO3 formation.
• The reaction's behavior is highly sensitive to confinement, surface chemistry, and CO2 concentration.
• Provides a detailed mechanistic understanding of carbonation processes in confined spaces.