Interfacial Hydrogen-Bond Dynamics in Transition Metal Compounds

Area of Science:

• Materials Science
• Physical Chemistry
• Surface Science

Background:

• Understanding water behavior in confined atomic layers is crucial for engineering solid-liquid interfaces.
• Lattice element chemistry and surface termination groups' roles in regulating interlayer water dynamics are not well understood.

Purpose of the Study:

• To investigate interlayer water dynamics in layered transition-metal nitride, carbide, and carbonitride systems.
• To understand how lattice composition and surface chemistry collectively control water structure and mobility.

Main Methods:

• Quasi-elastic neutron scattering (QENS) for experimental dynamics.
• Ab initio molecular dynamics (AIMD) simulations for atomic-level insights.
• Density functional theory (DFT) calculations for electronic structure and bonding.

Main Results:

• Nitride-rich systems exhibit mobile, translationally diffusing water (D ~ 10^-10 m^2 s^-1).
• Mixed C/N lattices confine water to localized, temperature-insensitive motion.
• Lattice and surface chemistry modulate electronic structure and hydrogen-bond networks, affecting water ordering and resilience.

Conclusions:

• Water mobility is controlled by the interplay of lattice composition and surface chemistry, not just hydration level.
• A mechanistic framework is established for designing transition-metal layered materials with tunable interfacial transport.