Water molecules in boron nitride interlayer space: ice and hydrolysis in super confinement

Area of Science:

• Materials Science
• Physical Chemistry
• Nanotechnology

Background:

• Nano-sized channels and filters are increasingly important.
• Water molecule behavior significantly impacts the performance and durability of nanomaterials.
• Understanding water confinement effects is crucial for advancing nanotechnology.

Purpose of the Study:

• To investigate the behavior of water molecules confined between hexagonal boron nitride (HBN) sheets.
• To explore the effects of varying interlayer spacing on water-HBN interactions.
• To elucidate the mechanisms of water molecule transformation under extreme confinement.

Main Methods:

• Utilized molecular dynamics (MD) and density functional theory (DFT) simulations.
• Analyzed charge transfer and molecular interactions at different interlayer spaces (3.0 to 6.5 Å).
• Investigated the functionalization of HBN sheets and proton transport mechanisms.

Main Results:

• Lower interlayer spaces resulted in increased charge transfer between water and HBN.
• Extreme confinement led to the disintegration of water molecules.
• Observed functionalization of HBN with hydroxyl groups and proton transport via the Grotthuss mechanism.

Conclusions:

• Demonstrated a novel mechanical hydrolysis of water under extreme confinement.
• Identified a nucleophilic attack on boron atoms as a key process.
• Revealed previously unknown water behavior in confined environments, with implications for nanofilter and nanochannel design.