Hydration Structures on γ-Alumina Surfaces With and Without Electrolytes Probed by Atomistic Molecular Dynamics...

Area of Science:

• Surface Science
• Physical Chemistry
• Computational Materials Science

Background:

• Aqueous electrolyte solutions at interfaces are crucial in many engineered and natural systems.
• Understanding surface-water and ion-surface interactions is vital for applications like catalysis and water treatment.

Purpose of the Study:

• To investigate water structure and dynamics at gamma-alumina [110] and [100] terminations.
• To examine the influence of various salts (NaCl, NH4OAc, Ba(OAc)2, Ba(NO3)2) on these interfacial properties.

Main Methods:

• Equilibrium molecular dynamics simulations were employed.
• Interfacial phenomena were quantified using atomic density profiles, angle distributions, residence times, and hydrogen bond analysis.
• Simulation snapshots aided result interpretation.

Main Results:

• Water shows stronger interaction and closer association with the [110] surface compared to the [100] surface.
• Ion-induced disruption of interfacial water structure was more pronounced at the [100] surface.
• Cation adsorption (Na+, NH4+) at the [100] surface was stronger and appeared size-dependent.

Conclusions:

• Surface characteristics, such as atomistic roughness of the [110] surface, dictate surface-water interactions.
• Differences in surface features influence ion-surface and ion-water interactions.
• Findings offer insights for catalyst design and adsorption-based water treatment.